drivers/scsi/st.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   4    file Documentation/scsi/st.txt for more information.
   5
   6    History:
   7    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   8    Contribution and ideas from several people including (in alphabetical
   9    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
  10    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  11    Michael Schaefer, J"org Weule, and Eric Youngdale.
  12
  13    Copyright 1992 - 2016 Kai Makisara
  14    email Kai.Makisara@kolumbus.fi
  15
  16    Some small formal changes - aeb, 950809
  17
  18    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  19  */
  20
  21 static const char *verstr = "20160209";
  22
  23 #include <linux/module.h>
  24
  25 #include <linux/fs.h>
  26 #include <linux/kernel.h>
  27 #include <linux/sched/signal.h>
  28 #include <linux/mm.h>
  29 #include <linux/init.h>
  30 #include <linux/string.h>
  31 #include <linux/slab.h>
  32 #include <linux/errno.h>
  33 #include <linux/mtio.h>
  34 #include <linux/cdrom.h>
  35 #include <linux/ioctl.h>
  36 #include <linux/fcntl.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/blkdev.h>
  39 #include <linux/moduleparam.h>
  40 #include <linux/cdev.h>
  41 #include <linux/idr.h>
  42 #include <linux/delay.h>
  43 #include <linux/mutex.h>
  44
  45 #include <linux/uaccess.h>
  46 #include <asm/dma.h>
  47
  48 #include <scsi/scsi.h>
  49 #include <scsi/scsi_dbg.h>
  50 #include <scsi/scsi_device.h>
  51 #include <scsi/scsi_driver.h>
  52 #include <scsi/scsi_eh.h>
  53 #include <scsi/scsi_host.h>
  54 #include <scsi/scsi_ioctl.h>
  55 #include <scsi/sg.h>
  56
  57
  58 /* The driver prints some debugging information on the console if DEBUG
  59    is defined and non-zero. */
  60 #define DEBUG 1
  61 #define NO_DEBUG 0
  62
  63 #define ST_DEB_MSG  KERN_NOTICE
  64 #if DEBUG
  65 /* The message level for the debug messages is currently set to KERN_NOTICE
  66    so that people can easily see the messages. Later when the debugging messages
  67    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  68 #define DEB(a) a
  69 #define DEBC(a) if (debugging) { a ; }
  70 #else
  71 #define DEB(a)
  72 #define DEBC(a)
  73 #endif
  74
  75 #define ST_KILOBYTE 1024
  76
  77 #include "st_options.h"
  78 #include "st.h"
  79
  80 static int buffer_kbs;
  81 static int max_sg_segs;
  82 static int try_direct_io = TRY_DIRECT_IO;
  83 static int try_rdio = 1;
  84 static int try_wdio = 1;
  85 static int debug_flag;
  86
  87 static struct class st_sysfs_class;
  88 static const struct attribute_group *st_dev_groups[];
  89 static const struct attribute_group *st_drv_groups[];
  90
  91 MODULE_AUTHOR("Kai Makisara");
  92 MODULE_DESCRIPTION("SCSI tape (st) driver");
  93 MODULE_LICENSE("GPL");
  94 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  95 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  96
  97 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
  98  * of sysfs parameters (which module_param doesn't yet support).
  99  * Sysfs parameters defined explicitly later.
 100  */
 101 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 102 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 103 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 104 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 105 module_param_named(try_direct_io, try_direct_io, int, 0);
 106 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 107 module_param_named(debug_flag, debug_flag, int, 0);
 108 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 109
 110
 111 /* Extra parameters for testing */
 112 module_param_named(try_rdio, try_rdio, int, 0);
 113 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 114 module_param_named(try_wdio, try_wdio, int, 0);
 115 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 116
 117 #ifndef MODULE
 118 static int write_threshold_kbs;  /* retained for compatibility */
 119 static struct st_dev_parm {
 120         char *name;
 121         int *val;
 122 } parms[] __initdata = {
 123         {
 124                 "buffer_kbs", &buffer_kbs
 125         },
 126         {       /* Retained for compatibility with 2.4 */
 127                 "write_threshold_kbs", &write_threshold_kbs
 128         },
 129         {
 130                 "max_sg_segs", NULL
 131         },
 132         {
 133                 "try_direct_io", &try_direct_io
 134         },
 135         {
 136                 "debug_flag", &debug_flag
 137         }
 138 };
 139 #endif
 140
 141 /* Restrict the number of modes so that names for all are assigned */
 142 #if ST_NBR_MODES > 16
 143 #error "Maximum number of modes is 16"
 144 #endif
 145 /* Bit reversed order to get same names for same minors with all
 146    mode counts */
 147 static const char *st_formats[] = {
 148         "",  "r", "k", "s", "l", "t", "o", "u",
 149         "m", "v", "p", "x", "a", "y", "q", "z"};
 150
 151 /* The default definitions have been moved to st_options.h */
 152
 153 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 154
 155 /* The buffer size should fit into the 24 bits for length in the
 156    6-byte SCSI read and write commands. */
 157 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 158 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 159 #endif
 160
 161 static int debugging = DEBUG;
 162
 163 #define MAX_RETRIES 0
 164 #define MAX_WRITE_RETRIES 0
 165 #define MAX_READY_RETRIES 0
 166 #define NO_TAPE  NOT_READY
 167
 168 #define ST_TIMEOUT (900 * HZ)
 169 #define ST_LONG_TIMEOUT (14000 * HZ)
 170
 171 /* Remove mode bits and auto-rewind bit (7) */
 172 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 173         (iminor(x) & ((1 << ST_MODE_SHIFT)-1)))
 174 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 175
 176 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 177 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 178   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 179
 180 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 181    24 bits) */
 182 #define SET_DENS_AND_BLK 0x10001
 183
 184 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 185 static int st_max_sg_segs = ST_MAX_SG;
 186
 187 static int modes_defined;
 188
 189 static int enlarge_buffer(struct st_buffer *, int, int);
 190 static void clear_buffer(struct st_buffer *);
 191 static void normalize_buffer(struct st_buffer *);
 192 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 193 static int from_buffer(struct st_buffer *, char __user *, int);
 194 static void move_buffer_data(struct st_buffer *, int);
 195
 196 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 197                               unsigned long, size_t, int);
 198 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 199
 200 static int st_probe(struct device *);
 201 static int st_remove(struct device *);
 202
 203 static struct scsi_driver st_template = {
 204         .gendrv = {
 205                 .name           = "st",
 206                 .owner          = THIS_MODULE,
 207                 .probe          = st_probe,
 208                 .remove         = st_remove,
 209                 .groups         = st_drv_groups,
 210         },
 211 };
 212
 213 static int st_compression(struct scsi_tape *, int);
 214
 215 static int find_partition(struct scsi_tape *);
 216 static int switch_partition(struct scsi_tape *);
 217
 218 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 219
 220 static void scsi_tape_release(struct kref *);
 221
 222 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 223
 224 static DEFINE_MUTEX(st_ref_mutex);
 225 static DEFINE_SPINLOCK(st_index_lock);
 226 static DEFINE_SPINLOCK(st_use_lock);
 227 static DEFINE_IDR(st_index_idr);
 228
 229
 230 \f
 231 #include "osst_detect.h"
 232 #ifndef SIGS_FROM_OSST
 233 #define SIGS_FROM_OSST \
 234         {"OnStream", "SC-", "", "osst"}, \
 235         {"OnStream", "DI-", "", "osst"}, \
 236         {"OnStream", "DP-", "", "osst"}, \
 237         {"OnStream", "USB", "", "osst"}, \
 238         {"OnStream", "FW-", "", "osst"}
 239 #endif
 240
 241 static struct scsi_tape *scsi_tape_get(int dev)
 242 {
 243         struct scsi_tape *STp = NULL;
 244
 245         mutex_lock(&st_ref_mutex);
 246         spin_lock(&st_index_lock);
 247
 248         STp = idr_find(&st_index_idr, dev);
 249         if (!STp) goto out;
 250
 251         kref_get(&STp->kref);
 252
 253         if (!STp->device)
 254                 goto out_put;
 255
 256         if (scsi_device_get(STp->device))
 257                 goto out_put;
 258
 259         goto out;
 260
 261 out_put:
 262         kref_put(&STp->kref, scsi_tape_release);
 263         STp = NULL;
 264 out:
 265         spin_unlock(&st_index_lock);
 266         mutex_unlock(&st_ref_mutex);
 267         return STp;
 268 }
 269
 270 static void scsi_tape_put(struct scsi_tape *STp)
 271 {
 272         struct scsi_device *sdev = STp->device;
 273
 274         mutex_lock(&st_ref_mutex);
 275         kref_put(&STp->kref, scsi_tape_release);
 276         scsi_device_put(sdev);
 277         mutex_unlock(&st_ref_mutex);
 278 }
 279
 280 struct st_reject_data {
 281         char *vendor;
 282         char *model;
 283         char *rev;
 284         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 285 };
 286
 287 static struct st_reject_data reject_list[] = {
 288         /* {"XXX", "Yy-", "", NULL},  example */
 289         SIGS_FROM_OSST,
 290         {NULL, }};
 291
 292 /* If the device signature is on the list of incompatible drives, the
 293    function returns a pointer to the name of the correct driver (if known) */
 294 static char * st_incompatible(struct scsi_device* SDp)
 295 {
 296         struct st_reject_data *rp;
 297
 298         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 299                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 300                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 301                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 302                         if (rp->driver_hint)
 303                                 return rp->driver_hint;
 304                         else
 305                                 return "unknown";
 306                 }
 307         return NULL;
 308 }
 309 \f
 310
 311 static inline char *tape_name(struct scsi_tape *tape)
 312 {
 313         return tape->disk->disk_name;
 314 }
 315
 316 #define st_printk(prefix, t, fmt, a...) \
 317         sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 318 #ifdef DEBUG
 319 #define DEBC_printk(t, fmt, a...) \
 320         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 321 #else
 322 #define DEBC_printk(t, fmt, a...)
 323 #endif
 324
 325 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 326 {
 327         const u8 *ucp;
 328         const u8 *sense = SRpnt->sense;
 329
 330         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 331                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 332         s->flags = 0;
 333
 334         if (s->have_sense) {
 335                 s->deferred = 0;
 336                 s->remainder_valid =
 337                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 338                 switch (sense[0] & 0x7f) {
 339                 case 0x71:
 340                         s->deferred = 1;
 341                         /* fall through */
 342                 case 0x70:
 343                         s->fixed_format = 1;
 344                         s->flags = sense[2] & 0xe0;
 345                         break;
 346                 case 0x73:
 347                         s->deferred = 1;
 348                         /* fall through */
 349                 case 0x72:
 350                         s->fixed_format = 0;
 351                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 352                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 353                         break;
 354                 }
 355         }
 356 }
 357
 358
 359 /* Convert the result to success code */
 360 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 361 {
 362         int result = SRpnt->result;
 363         u8 scode;
 364         DEB(const char *stp;)
 365         char *name = tape_name(STp);
 366         struct st_cmdstatus *cmdstatp;
 367
 368         if (!result)
 369                 return 0;
 370
 371         cmdstatp = &STp->buffer->cmdstat;
 372         st_analyze_sense(SRpnt, cmdstatp);
 373
 374         if (cmdstatp->have_sense)
 375                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 376         else
 377                 scode = 0;
 378
 379         DEB(
 380         if (debugging) {
 381                 st_printk(ST_DEB_MSG, STp,
 382                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 383                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 384                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 385                 if (cmdstatp->have_sense)
 386                         __scsi_print_sense(STp->device, name,
 387                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 388         } ) /* end DEB */
 389         if (!debugging) { /* Abnormal conditions for tape */
 390                 if (!cmdstatp->have_sense)
 391                         st_printk(KERN_WARNING, STp,
 392                                "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 393                                result, driver_byte(result), host_byte(result));
 394                 else if (cmdstatp->have_sense &&
 395                          scode != NO_SENSE &&
 396                          scode != RECOVERED_ERROR &&
 397                          /* scode != UNIT_ATTENTION && */
 398                          scode != BLANK_CHECK &&
 399                          scode != VOLUME_OVERFLOW &&
 400                          SRpnt->cmd[0] != MODE_SENSE &&
 401                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 402
 403                         __scsi_print_sense(STp->device, name,
 404                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 405                 }
 406         }
 407
 408         if (cmdstatp->fixed_format &&
 409             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 410                 if (STp->cln_sense_value)
 411                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412                                                STp->cln_sense_mask) == STp->cln_sense_value);
 413                 else
 414                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 415                                                STp->cln_sense_mask) != 0);
 416         }
 417         if (cmdstatp->have_sense &&
 418             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 419                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 420
 421         STp->pos_unknown |= STp->device->was_reset;
 422
 423         if (cmdstatp->have_sense &&
 424             scode == RECOVERED_ERROR
 425 #if ST_RECOVERED_WRITE_FATAL
 426             && SRpnt->cmd[0] != WRITE_6
 427             && SRpnt->cmd[0] != WRITE_FILEMARKS
 428 #endif
 429             ) {
 430                 STp->recover_count++;
 431                 STp->recover_reg++;
 432
 433                 DEB(
 434                 if (debugging) {
 435                         if (SRpnt->cmd[0] == READ_6)
 436                                 stp = "read";
 437                         else if (SRpnt->cmd[0] == WRITE_6)
 438                                 stp = "write";
 439                         else
 440                                 stp = "ioctl";
 441                         st_printk(ST_DEB_MSG, STp,
 442                                   "Recovered %s error (%d).\n",
 443                                   stp, STp->recover_count);
 444                 } ) /* end DEB */
 445
 446                 if (cmdstatp->flags == 0)
 447                         return 0;
 448         }
 449         return (-EIO);
 450 }
 451
 452 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 453 {
 454         struct st_request *streq;
 455
 456         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 457         if (streq)
 458                 streq->stp = stp;
 459         else {
 460                 st_printk(KERN_ERR, stp,
 461                           "Can't get SCSI request.\n");
 462                 if (signal_pending(current))
 463                         stp->buffer->syscall_result = -EINTR;
 464                 else
 465                         stp->buffer->syscall_result = -EBUSY;
 466         }
 467
 468         return streq;
 469 }
 470
 471 static void st_release_request(struct st_request *streq)
 472 {
 473         kfree(streq);
 474 }
 475
 476 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 477 {
 478         ktime_t now;
 479
 480         now = ktime_get();
 481         if (scsi_req(req)->cmd[0] == WRITE_6) {
 482                 now = ktime_sub(now, STp->stats->write_time);
 483                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 484                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 485                 atomic64_inc(&STp->stats->write_cnt);
 486                 if (scsi_req(req)->result) {
 487                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 488                                 - STp->buffer->cmdstat.residual,
 489                                 &STp->stats->write_byte_cnt);
 490                         if (STp->buffer->cmdstat.residual > 0)
 491                                 atomic64_inc(&STp->stats->resid_cnt);
 492                 } else
 493                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 494                                 &STp->stats->write_byte_cnt);
 495         } else if (scsi_req(req)->cmd[0] == READ_6) {
 496                 now = ktime_sub(now, STp->stats->read_time);
 497                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 498                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 499                 atomic64_inc(&STp->stats->read_cnt);
 500                 if (scsi_req(req)->result) {
 501                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 502                                 - STp->buffer->cmdstat.residual,
 503                                 &STp->stats->read_byte_cnt);
 504                         if (STp->buffer->cmdstat.residual > 0)
 505                                 atomic64_inc(&STp->stats->resid_cnt);
 506                 } else
 507                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 508                                 &STp->stats->read_byte_cnt);
 509         } else {
 510                 now = ktime_sub(now, STp->stats->other_time);
 511                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 512                 atomic64_inc(&STp->stats->other_cnt);
 513         }
 514         atomic64_dec(&STp->stats->in_flight);
 515 }
 516
 517 static void st_scsi_execute_end(struct request *req, blk_status_t status)
 518 {
 519         struct st_request *SRpnt = req->end_io_data;
 520         struct scsi_request *rq = scsi_req(req);
 521         struct scsi_tape *STp = SRpnt->stp;
 522         struct bio *tmp;
 523
 524         STp->buffer->cmdstat.midlevel_result = SRpnt->result = rq->result;
 525         STp->buffer->cmdstat.residual = rq->resid_len;
 526
 527         st_do_stats(STp, req);
 528
 529         tmp = SRpnt->bio;
 530         if (rq->sense_len)
 531                 memcpy(SRpnt->sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
 532         if (SRpnt->waiting)
 533                 complete(SRpnt->waiting);
 534
 535         blk_rq_unmap_user(tmp);
 536         blk_put_request(req);
 537 }
 538
 539 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 540                            int data_direction, void *buffer, unsigned bufflen,
 541                            int timeout, int retries)
 542 {
 543         struct request *req;
 544         struct scsi_request *rq;
 545         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 546         int err = 0;
 547         struct scsi_tape *STp = SRpnt->stp;
 548
 549         req = blk_get_request(SRpnt->stp->device->request_queue,
 550                         data_direction == DMA_TO_DEVICE ?
 551                         REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 552         if (IS_ERR(req))
 553                 return DRIVER_ERROR << 24;
 554         rq = scsi_req(req);
 555         req->rq_flags |= RQF_QUIET;
 556
 557         mdata->null_mapped = 1;
 558
 559         if (bufflen) {
 560                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 561                                       GFP_KERNEL);
 562                 if (err) {
 563                         blk_put_request(req);
 564                         return DRIVER_ERROR << 24;
 565                 }
 566         }
 567
 568         atomic64_inc(&STp->stats->in_flight);
 569         if (cmd[0] == WRITE_6) {
 570                 atomic_set(&STp->stats->last_write_size, bufflen);
 571                 STp->stats->write_time = ktime_get();
 572         } else if (cmd[0] == READ_6) {
 573                 atomic_set(&STp->stats->last_read_size, bufflen);
 574                 STp->stats->read_time = ktime_get();
 575         } else {
 576                 STp->stats->other_time = ktime_get();
 577         }
 578
 579         SRpnt->bio = req->bio;
 580         rq->cmd_len = COMMAND_SIZE(cmd[0]);
 581         memset(rq->cmd, 0, BLK_MAX_CDB);
 582         memcpy(rq->cmd, cmd, rq->cmd_len);
 583         req->timeout = timeout;
 584         rq->retries = retries;
 585         req->end_io_data = SRpnt;
 586
 587         blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 588         return 0;
 589 }
 590
 591 /* Do the scsi command. Waits until command performed if do_wait is true.
 592    Otherwise write_behind_check() is used to check that the command
 593    has finished. */
 594 static struct st_request *
 595 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 596            int bytes, int direction, int timeout, int retries, int do_wait)
 597 {
 598         struct completion *waiting;
 599         struct rq_map_data *mdata = &STp->buffer->map_data;
 600         int ret;
 601
 602         /* if async, make sure there's no command outstanding */
 603         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 604                 st_printk(KERN_ERR, STp,
 605                           "Async command already active.\n");
 606                 if (signal_pending(current))
 607                         (STp->buffer)->syscall_result = (-EINTR);
 608                 else
 609                         (STp->buffer)->syscall_result = (-EBUSY);
 610                 return NULL;
 611         }
 612
 613         if (!SRpnt) {
 614                 SRpnt = st_allocate_request(STp);
 615                 if (!SRpnt)
 616                         return NULL;
 617         }
 618
 619         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 620            which IO is outstanding. It's nulled out when the IO completes. */
 621         if (!do_wait)
 622                 (STp->buffer)->last_SRpnt = SRpnt;
 623
 624         waiting = &STp->wait;
 625         init_completion(waiting);
 626         SRpnt->waiting = waiting;
 627
 628         if (STp->buffer->do_dio) {
 629                 mdata->page_order = 0;
 630                 mdata->nr_entries = STp->buffer->sg_segs;
 631                 mdata->pages = STp->buffer->mapped_pages;
 632         } else {
 633                 mdata->page_order = STp->buffer->reserved_page_order;
 634                 mdata->nr_entries =
 635                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 636                 mdata->pages = STp->buffer->reserved_pages;
 637                 mdata->offset = 0;
 638         }
 639
 640         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 641         STp->buffer->cmdstat.have_sense = 0;
 642         STp->buffer->syscall_result = 0;
 643
 644         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 645                               retries);
 646         if (ret) {
 647                 /* could not allocate the buffer or request was too large */
 648                 (STp->buffer)->syscall_result = (-EBUSY);
 649                 (STp->buffer)->last_SRpnt = NULL;
 650         } else if (do_wait) {
 651                 wait_for_completion(waiting);
 652                 SRpnt->waiting = NULL;
 653                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 654         }
 655
 656         return SRpnt;
 657 }
 658
 659
 660 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 661    write has been correct but EOM early warning reached, -EIO if write ended in
 662    error or zero if write successful. Asynchronous writes are used only in
 663    variable block mode. */
 664 static int write_behind_check(struct scsi_tape * STp)
 665 {
 666         int retval = 0;
 667         struct st_buffer *STbuffer;
 668         struct st_partstat *STps;
 669         struct st_cmdstatus *cmdstatp;
 670         struct st_request *SRpnt;
 671
 672         STbuffer = STp->buffer;
 673         if (!STbuffer->writing)
 674                 return 0;
 675
 676         DEB(
 677         if (STp->write_pending)
 678                 STp->nbr_waits++;
 679         else
 680                 STp->nbr_finished++;
 681         ) /* end DEB */
 682
 683         wait_for_completion(&(STp->wait));
 684         SRpnt = STbuffer->last_SRpnt;
 685         STbuffer->last_SRpnt = NULL;
 686         SRpnt->waiting = NULL;
 687
 688         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 689         st_release_request(SRpnt);
 690
 691         STbuffer->buffer_bytes -= STbuffer->writing;
 692         STps = &(STp->ps[STp->partition]);
 693         if (STps->drv_block >= 0) {
 694                 if (STp->block_size == 0)
 695                         STps->drv_block++;
 696                 else
 697                         STps->drv_block += STbuffer->writing / STp->block_size;
 698         }
 699
 700         cmdstatp = &STbuffer->cmdstat;
 701         if (STbuffer->syscall_result) {
 702                 retval = -EIO;
 703                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 704                     (cmdstatp->flags & SENSE_EOM) &&
 705                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 706                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 707                         /* EOM at write-behind, has all data been written? */
 708                         if (!cmdstatp->remainder_valid ||
 709                             cmdstatp->uremainder64 == 0)
 710                                 retval = -ENOSPC;
 711                 }
 712                 if (retval == -EIO)
 713                         STps->drv_block = -1;
 714         }
 715         STbuffer->writing = 0;
 716
 717         DEB(if (debugging && retval)
 718                     st_printk(ST_DEB_MSG, STp,
 719                                 "Async write error %x, return value %d.\n",
 720                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 721
 722         return retval;
 723 }
 724
 725
 726 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 727    it messes up the block number). */
 728 static int cross_eof(struct scsi_tape * STp, int forward)
 729 {
 730         struct st_request *SRpnt;
 731         unsigned char cmd[MAX_COMMAND_SIZE];
 732
 733         cmd[0] = SPACE;
 734         cmd[1] = 0x01;          /* Space FileMarks */
 735         if (forward) {
 736                 cmd[2] = cmd[3] = 0;
 737                 cmd[4] = 1;
 738         } else
 739                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 740         cmd[5] = 0;
 741
 742         DEBC_printk(STp, "Stepping over filemark %s.\n",
 743                     forward ? "forward" : "backward");
 744
 745         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 746                            STp->device->request_queue->rq_timeout,
 747                            MAX_RETRIES, 1);
 748         if (!SRpnt)
 749                 return (STp->buffer)->syscall_result;
 750
 751         st_release_request(SRpnt);
 752         SRpnt = NULL;
 753
 754         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 755                 st_printk(KERN_ERR, STp,
 756                           "Stepping over filemark %s failed.\n",
 757                           forward ? "forward" : "backward");
 758
 759         return (STp->buffer)->syscall_result;
 760 }
 761
 762
 763 /* Flush the write buffer (never need to write if variable blocksize). */
 764 static int st_flush_write_buffer(struct scsi_tape * STp)
 765 {
 766         int transfer, blks;
 767         int result;
 768         unsigned char cmd[MAX_COMMAND_SIZE];
 769         struct st_request *SRpnt;
 770         struct st_partstat *STps;
 771
 772         result = write_behind_check(STp);
 773         if (result)
 774                 return result;
 775
 776         result = 0;
 777         if (STp->dirty == 1) {
 778
 779                 transfer = STp->buffer->buffer_bytes;
 780                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 781
 782                 memset(cmd, 0, MAX_COMMAND_SIZE);
 783                 cmd[0] = WRITE_6;
 784                 cmd[1] = 1;
 785                 blks = transfer / STp->block_size;
 786                 cmd[2] = blks >> 16;
 787                 cmd[3] = blks >> 8;
 788                 cmd[4] = blks;
 789
 790                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 791                                    STp->device->request_queue->rq_timeout,
 792                                    MAX_WRITE_RETRIES, 1);
 793                 if (!SRpnt)
 794                         return (STp->buffer)->syscall_result;
 795
 796                 STps = &(STp->ps[STp->partition]);
 797                 if ((STp->buffer)->syscall_result != 0) {
 798                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 799
 800                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 801                             (cmdstatp->flags & SENSE_EOM) &&
 802                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 803                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 804                             (!cmdstatp->remainder_valid ||
 805                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 806                                 STp->dirty = 0;
 807                                 (STp->buffer)->buffer_bytes = 0;
 808                                 if (STps->drv_block >= 0)
 809                                         STps->drv_block += blks;
 810                                 result = (-ENOSPC);
 811                         } else {
 812                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 813                                 STps->drv_block = (-1);
 814                                 result = (-EIO);
 815                         }
 816                 } else {
 817                         if (STps->drv_block >= 0)
 818                                 STps->drv_block += blks;
 819                         STp->dirty = 0;
 820                         (STp->buffer)->buffer_bytes = 0;
 821                 }
 822                 st_release_request(SRpnt);
 823                 SRpnt = NULL;
 824         }
 825         return result;
 826 }
 827
 828
 829 /* Flush the tape buffer. The tape will be positioned correctly unless
 830    seek_next is true. */
 831 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 832 {
 833         int backspace, result;
 834         struct st_partstat *STps;
 835
 836         /*
 837          * If there was a bus reset, block further access
 838          * to this device.
 839          */
 840         if (STp->pos_unknown)
 841                 return (-EIO);
 842
 843         if (STp->ready != ST_READY)
 844                 return 0;
 845         STps = &(STp->ps[STp->partition]);
 846         if (STps->rw == ST_WRITING)     /* Writing */
 847                 return st_flush_write_buffer(STp);
 848
 849         if (STp->block_size == 0)
 850                 return 0;
 851
 852         backspace = ((STp->buffer)->buffer_bytes +
 853                      (STp->buffer)->read_pointer) / STp->block_size -
 854             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 855             STp->block_size;
 856         (STp->buffer)->buffer_bytes = 0;
 857         (STp->buffer)->read_pointer = 0;
 858         result = 0;
 859         if (!seek_next) {
 860                 if (STps->eof == ST_FM_HIT) {
 861                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 862                         if (!result)
 863                                 STps->eof = ST_NOEOF;
 864                         else {
 865                                 if (STps->drv_file >= 0)
 866                                         STps->drv_file++;
 867                                 STps->drv_block = 0;
 868                         }
 869                 }
 870                 if (!result && backspace > 0)
 871                         result = st_int_ioctl(STp, MTBSR, backspace);
 872         } else if (STps->eof == ST_FM_HIT) {
 873                 if (STps->drv_file >= 0)
 874                         STps->drv_file++;
 875                 STps->drv_block = 0;
 876                 STps->eof = ST_NOEOF;
 877         }
 878         return result;
 879
 880 }
 881 \f
 882 /* Set the mode parameters */
 883 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 884 {
 885         int set_it = 0;
 886         unsigned long arg;
 887
 888         if (!STp->density_changed &&
 889             STm->default_density >= 0 &&
 890             STm->default_density != STp->density) {
 891                 arg = STm->default_density;
 892                 set_it = 1;
 893         } else
 894                 arg = STp->density;
 895         arg <<= MT_ST_DENSITY_SHIFT;
 896         if (!STp->blksize_changed &&
 897             STm->default_blksize >= 0 &&
 898             STm->default_blksize != STp->block_size) {
 899                 arg |= STm->default_blksize;
 900                 set_it = 1;
 901         } else
 902                 arg |= STp->block_size;
 903         if (set_it &&
 904             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 905                 st_printk(KERN_WARNING, STp,
 906                           "Can't set default block size to %d bytes "
 907                           "and density %x.\n",
 908                           STm->default_blksize, STm->default_density);
 909                 if (modes_defined)
 910                         return (-EINVAL);
 911         }
 912         return 0;
 913 }
 914
 915
 916 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 917 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 918 {
 919         int retval;
 920
 921         DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 922
 923         retval = scsi_set_medium_removal(STp->device,
 924                         do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 925         if (!retval)
 926                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 927         else
 928                 STp->door_locked = ST_LOCK_FAILS;
 929         return retval;
 930 }
 931
 932
 933 /* Set the internal state after reset */
 934 static void reset_state(struct scsi_tape *STp)
 935 {
 936         int i;
 937         struct st_partstat *STps;
 938
 939         STp->pos_unknown = 0;
 940         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 941                 STps = &(STp->ps[i]);
 942                 STps->rw = ST_IDLE;
 943                 STps->eof = ST_NOEOF;
 944                 STps->at_sm = 0;
 945                 STps->last_block_valid = 0;
 946                 STps->drv_block = -1;
 947                 STps->drv_file = -1;
 948         }
 949         if (STp->can_partitions) {
 950                 STp->partition = find_partition(STp);
 951                 if (STp->partition < 0)
 952                         STp->partition = 0;
 953                 STp->new_partition = STp->partition;
 954         }
 955 }
 956 \f
 957 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 958    error code. */
 959 #define CHKRES_READY       0
 960 #define CHKRES_NEW_SESSION 1
 961 #define CHKRES_NOT_READY   2
 962 #define CHKRES_NO_TAPE     3
 963
 964 #define MAX_ATTENTIONS    10
 965
 966 static int test_ready(struct scsi_tape *STp, int do_wait)
 967 {
 968         int attentions, waits, max_wait, scode;
 969         int retval = CHKRES_READY, new_session = 0;
 970         unsigned char cmd[MAX_COMMAND_SIZE];
 971         struct st_request *SRpnt = NULL;
 972         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 973
 974         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 975
 976         for (attentions=waits=0; ; ) {
 977                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 978                 cmd[0] = TEST_UNIT_READY;
 979                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 980                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 981
 982                 if (!SRpnt) {
 983                         retval = (STp->buffer)->syscall_result;
 984                         break;
 985                 }
 986
 987                 if (cmdstatp->have_sense) {
 988
 989                         scode = cmdstatp->sense_hdr.sense_key;
 990
 991                         if (scode == UNIT_ATTENTION) { /* New media? */
 992                                 new_session = 1;
 993                                 if (attentions < MAX_ATTENTIONS) {
 994                                         attentions++;
 995                                         continue;
 996                                 }
 997                                 else {
 998                                         retval = (-EIO);
 999                                         break;
1000                                 }
1001                         }
1002
1003                         if (scode == NOT_READY) {
1004                                 if (waits < max_wait) {
1005                                         if (msleep_interruptible(1000)) {
1006                                                 retval = (-EINTR);
1007                                                 break;
1008                                         }
1009                                         waits++;
1010                                         continue;
1011                                 }
1012                                 else {
1013                                         if ((STp->device)->scsi_level >= SCSI_2 &&
1014                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
1015                                                 retval = CHKRES_NO_TAPE;
1016                                         else
1017                                                 retval = CHKRES_NOT_READY;
1018                                         break;
1019                                 }
1020                         }
1021                 }
1022
1023                 retval = (STp->buffer)->syscall_result;
1024                 if (!retval)
1025                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1026                 break;
1027         }
1028
1029         if (SRpnt != NULL)
1030                 st_release_request(SRpnt);
1031         return retval;
1032 }
1033
1034
1035 /* See if the drive is ready and gather information about the tape. Return values:
1036    < 0   negative error code from errno.h
1037    0     drive ready
1038    1     drive not ready (possibly no tape)
1039 */
1040 static int check_tape(struct scsi_tape *STp, struct file *filp)
1041 {
1042         int i, retval, new_session = 0, do_wait;
1043         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1044         unsigned short st_flags = filp->f_flags;
1045         struct st_request *SRpnt = NULL;
1046         struct st_modedef *STm;
1047         struct st_partstat *STps;
1048         struct inode *inode = file_inode(filp);
1049         int mode = TAPE_MODE(inode);
1050
1051         STp->ready = ST_READY;
1052
1053         if (mode != STp->current_mode) {
1054                 DEBC_printk(STp, "Mode change from %d to %d.\n",
1055                             STp->current_mode, mode);
1056                 new_session = 1;
1057                 STp->current_mode = mode;
1058         }
1059         STm = &(STp->modes[STp->current_mode]);
1060
1061         saved_cleaning = STp->cleaning_req;
1062         STp->cleaning_req = 0;
1063
1064         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1065         retval = test_ready(STp, do_wait);
1066
1067         if (retval < 0)
1068             goto err_out;
1069
1070         if (retval == CHKRES_NEW_SESSION) {
1071                 STp->pos_unknown = 0;
1072                 STp->partition = STp->new_partition = 0;
1073                 if (STp->can_partitions)
1074                         STp->nbr_partitions = 1; /* This guess will be updated later
1075                                                     if necessary */
1076                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1077                         STps = &(STp->ps[i]);
1078                         STps->rw = ST_IDLE;
1079                         STps->eof = ST_NOEOF;
1080                         STps->at_sm = 0;
1081                         STps->last_block_valid = 0;
1082                         STps->drv_block = 0;
1083                         STps->drv_file = 0;
1084                 }
1085                 new_session = 1;
1086         }
1087         else {
1088                 STp->cleaning_req |= saved_cleaning;
1089
1090                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1091                         if (retval == CHKRES_NO_TAPE)
1092                                 STp->ready = ST_NO_TAPE;
1093                         else
1094                                 STp->ready = ST_NOT_READY;
1095
1096                         STp->density = 0;       /* Clear the erroneous "residue" */
1097                         STp->write_prot = 0;
1098                         STp->block_size = 0;
1099                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1100                         STp->partition = STp->new_partition = 0;
1101                         STp->door_locked = ST_UNLOCKED;
1102                         return CHKRES_NOT_READY;
1103                 }
1104         }
1105
1106         if (STp->omit_blklims)
1107                 STp->min_block = STp->max_block = (-1);
1108         else {
1109                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1110                 cmd[0] = READ_BLOCK_LIMITS;
1111
1112                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1113                                    STp->device->request_queue->rq_timeout,
1114                                    MAX_READY_RETRIES, 1);
1115                 if (!SRpnt) {
1116                         retval = (STp->buffer)->syscall_result;
1117                         goto err_out;
1118                 }
1119
1120                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1121                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1122                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1123                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1124                             (STp->buffer)->b_data[5];
1125                         if ( DEB( debugging || ) !STp->inited)
1126                                 st_printk(KERN_INFO, STp,
1127                                           "Block limits %d - %d bytes.\n",
1128                                           STp->min_block, STp->max_block);
1129                 } else {
1130                         STp->min_block = STp->max_block = (-1);
1131                         DEBC_printk(STp, "Can't read block limits.\n");
1132                 }
1133         }
1134
1135         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1136         cmd[0] = MODE_SENSE;
1137         cmd[4] = 12;
1138
1139         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1140                            STp->device->request_queue->rq_timeout,
1141                            MAX_READY_RETRIES, 1);
1142         if (!SRpnt) {
1143                 retval = (STp->buffer)->syscall_result;
1144                 goto err_out;
1145         }
1146
1147         if ((STp->buffer)->syscall_result != 0) {
1148                 DEBC_printk(STp, "No Mode Sense.\n");
1149                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1150                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1151                 STp->drv_write_prot = 0;
1152         } else {
1153                 DEBC_printk(STp,"Mode sense. Length %d, "
1154                             "medium %x, WBS %x, BLL %d\n",
1155                             (STp->buffer)->b_data[0],
1156                             (STp->buffer)->b_data[1],
1157                             (STp->buffer)->b_data[2],
1158                             (STp->buffer)->b_data[3]);
1159
1160                 if ((STp->buffer)->b_data[3] >= 8) {
1161                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1162                         STp->density = (STp->buffer)->b_data[4];
1163                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1164                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1165                         DEBC_printk(STp, "Density %x, tape length: %x, "
1166                                     "drv buffer: %d\n",
1167                                     STp->density,
1168                                     (STp->buffer)->b_data[5] * 65536 +
1169                                     (STp->buffer)->b_data[6] * 256 +
1170                                     (STp->buffer)->b_data[7],
1171                                     STp->drv_buffer);
1172                 }
1173                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1174                 if (!STp->drv_buffer && STp->immediate_filemark) {
1175                         st_printk(KERN_WARNING, STp,
1176                                   "non-buffered tape: disabling "
1177                                   "writing immediate filemarks\n");
1178                         STp->immediate_filemark = 0;
1179                 }
1180         }
1181         st_release_request(SRpnt);
1182         SRpnt = NULL;
1183         STp->inited = 1;
1184
1185         if (STp->block_size > 0)
1186                 (STp->buffer)->buffer_blocks =
1187                         (STp->buffer)->buffer_size / STp->block_size;
1188         else
1189                 (STp->buffer)->buffer_blocks = 1;
1190         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1191
1192         DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1193                     STp->block_size, (STp->buffer)->buffer_size,
1194                     (STp->buffer)->buffer_blocks);
1195
1196         if (STp->drv_write_prot) {
1197                 STp->write_prot = 1;
1198
1199                 DEBC_printk(STp, "Write protected\n");
1200
1201                 if (do_wait &&
1202                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1203                      (st_flags & O_ACCMODE) == O_RDWR)) {
1204                         retval = (-EROFS);
1205                         goto err_out;
1206                 }
1207         }
1208
1209         if (STp->can_partitions && STp->nbr_partitions < 1) {
1210                 /* This code is reached when the device is opened for the first time
1211                    after the driver has been initialized with tape in the drive and the
1212                    partition support has been enabled. */
1213                 DEBC_printk(STp, "Updating partition number in status.\n");
1214                 if ((STp->partition = find_partition(STp)) < 0) {
1215                         retval = STp->partition;
1216                         goto err_out;
1217                 }
1218                 STp->new_partition = STp->partition;
1219                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1220         }
1221
1222         if (new_session) {      /* Change the drive parameters for the new mode */
1223                 STp->density_changed = STp->blksize_changed = 0;
1224                 STp->compression_changed = 0;
1225                 if (!(STm->defaults_for_writes) &&
1226                     (retval = set_mode_densblk(STp, STm)) < 0)
1227                     goto err_out;
1228
1229                 if (STp->default_drvbuffer != 0xff) {
1230                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1231                                 st_printk(KERN_WARNING, STp,
1232                                           "Can't set default drive "
1233                                           "buffering to %d.\n",
1234                                           STp->default_drvbuffer);
1235                 }
1236         }
1237
1238         return CHKRES_READY;
1239
1240  err_out:
1241         return retval;
1242 }
1243
1244
1245 \f/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1246    module count. */
1247 static int st_open(struct inode *inode, struct file *filp)
1248 {
1249         int i, retval = (-EIO);
1250         int resumed = 0;
1251         struct scsi_tape *STp;
1252         struct st_partstat *STps;
1253         int dev = TAPE_NR(inode);
1254
1255         /*
1256          * We really want to do nonseekable_open(inode, filp); here, but some
1257          * versions of tar incorrectly call lseek on tapes and bail out if that
1258          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1259          */
1260         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1261
1262         if (!(STp = scsi_tape_get(dev))) {
1263                 return -ENXIO;
1264         }
1265
1266         filp->private_data = STp;
1267
1268         spin_lock(&st_use_lock);
1269         if (STp->in_use) {
1270                 spin_unlock(&st_use_lock);
1271                 scsi_tape_put(STp);
1272                 DEBC_printk(STp, "Device already in use.\n");
1273                 return (-EBUSY);
1274         }
1275
1276         STp->in_use = 1;
1277         spin_unlock(&st_use_lock);
1278         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1279
1280         if (scsi_autopm_get_device(STp->device) < 0) {
1281                 retval = -EIO;
1282                 goto err_out;
1283         }
1284         resumed = 1;
1285         if (!scsi_block_when_processing_errors(STp->device)) {
1286                 retval = (-ENXIO);
1287                 goto err_out;
1288         }
1289
1290         /* See that we have at least a one page buffer available */
1291         if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1292                 st_printk(KERN_WARNING, STp,
1293                           "Can't allocate one page tape buffer.\n");
1294                 retval = (-EOVERFLOW);
1295                 goto err_out;
1296         }
1297
1298         (STp->buffer)->cleared = 0;
1299         (STp->buffer)->writing = 0;
1300         (STp->buffer)->syscall_result = 0;
1301
1302         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1303
1304         STp->dirty = 0;
1305         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1306                 STps = &(STp->ps[i]);
1307                 STps->rw = ST_IDLE;
1308         }
1309         STp->try_dio_now = STp->try_dio;
1310         STp->recover_count = 0;
1311         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1312              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1313
1314         retval = check_tape(STp, filp);
1315         if (retval < 0)
1316                 goto err_out;
1317         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1318             retval != CHKRES_READY) {
1319                 if (STp->ready == NO_TAPE)
1320                         retval = (-ENOMEDIUM);
1321                 else
1322                         retval = (-EIO);
1323                 goto err_out;
1324         }
1325         return 0;
1326
1327  err_out:
1328         normalize_buffer(STp->buffer);
1329         spin_lock(&st_use_lock);
1330         STp->in_use = 0;
1331         spin_unlock(&st_use_lock);
1332         if (resumed)
1333                 scsi_autopm_put_device(STp->device);
1334         scsi_tape_put(STp);
1335         return retval;
1336
1337 }
1338 \f
1339
1340 /* Flush the tape buffer before close */
1341 static int st_flush(struct file *filp, fl_owner_t id)
1342 {
1343         int result = 0, result2;
1344         unsigned char cmd[MAX_COMMAND_SIZE];
1345         struct st_request *SRpnt;
1346         struct scsi_tape *STp = filp->private_data;
1347         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1348         struct st_partstat *STps = &(STp->ps[STp->partition]);
1349
1350         if (file_count(filp) > 1)
1351                 return 0;
1352
1353         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1354                 result = st_flush_write_buffer(STp);
1355                 if (result != 0 && result != (-ENOSPC))
1356                         goto out;
1357         }
1358
1359         if (STp->can_partitions &&
1360             (result2 = switch_partition(STp)) < 0) {
1361                 DEBC_printk(STp, "switch_partition at close failed.\n");
1362                 if (result == 0)
1363                         result = result2;
1364                 goto out;
1365         }
1366
1367         DEBC( if (STp->nbr_requests)
1368                 st_printk(KERN_DEBUG, STp,
1369                           "Number of r/w requests %d, dio used in %d, "
1370                           "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1371                           STp->nbr_pages));
1372
1373         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1374                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1375
1376 #if DEBUG
1377                 DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1378                             STp->nbr_waits, STp->nbr_finished);
1379 #endif
1380                 memset(cmd, 0, MAX_COMMAND_SIZE);
1381                 cmd[0] = WRITE_FILEMARKS;
1382                 if (STp->immediate_filemark)
1383                         cmd[1] = 1;
1384                 cmd[4] = 1 + STp->two_fm;
1385
1386                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1387                                    STp->device->request_queue->rq_timeout,
1388                                    MAX_WRITE_RETRIES, 1);
1389                 if (!SRpnt) {
1390                         result = (STp->buffer)->syscall_result;
1391                         goto out;
1392                 }
1393
1394                 if (STp->buffer->syscall_result == 0 ||
1395                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1396                      (cmdstatp->flags & SENSE_EOM) &&
1397                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1398                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1399                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1400                         /* Write successful at EOM */
1401                         st_release_request(SRpnt);
1402                         SRpnt = NULL;
1403                         if (STps->drv_file >= 0)
1404                                 STps->drv_file++;
1405                         STps->drv_block = 0;
1406                         if (STp->two_fm)
1407                                 cross_eof(STp, 0);
1408                         STps->eof = ST_FM;
1409                 }
1410                 else { /* Write error */
1411                         st_release_request(SRpnt);
1412                         SRpnt = NULL;
1413                         st_printk(KERN_ERR, STp,
1414                                   "Error on write filemark.\n");
1415                         if (result == 0)
1416                                 result = (-EIO);
1417                 }
1418
1419                 DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1420         } else if (!STp->rew_at_close) {
1421                 STps = &(STp->ps[STp->partition]);
1422                 if (!STm->sysv || STps->rw != ST_READING) {
1423                         if (STp->can_bsr)
1424                                 result = flush_buffer(STp, 0);
1425                         else if (STps->eof == ST_FM_HIT) {
1426                                 result = cross_eof(STp, 0);
1427                                 if (result) {
1428                                         if (STps->drv_file >= 0)
1429                                                 STps->drv_file++;
1430                                         STps->drv_block = 0;
1431                                         STps->eof = ST_FM;
1432                                 } else
1433                                         STps->eof = ST_NOEOF;
1434                         }
1435                 } else if ((STps->eof == ST_NOEOF &&
1436                             !(result = cross_eof(STp, 1))) ||
1437                            STps->eof == ST_FM_HIT) {
1438                         if (STps->drv_file >= 0)
1439                                 STps->drv_file++;
1440                         STps->drv_block = 0;
1441                         STps->eof = ST_FM;
1442                 }
1443         }
1444
1445       out:
1446         if (STp->rew_at_close) {
1447                 result2 = st_int_ioctl(STp, MTREW, 1);
1448                 if (result == 0)
1449                         result = result2;
1450         }
1451         return result;
1452 }
1453
1454
1455 /* Close the device and release it. BKL is not needed: this is the only thread
1456    accessing this tape. */
1457 static int st_release(struct inode *inode, struct file *filp)
1458 {
1459         int result = 0;
1460         struct scsi_tape *STp = filp->private_data;
1461
1462         if (STp->door_locked == ST_LOCKED_AUTO)
1463                 do_door_lock(STp, 0);
1464
1465         normalize_buffer(STp->buffer);
1466         spin_lock(&st_use_lock);
1467         STp->in_use = 0;
1468         spin_unlock(&st_use_lock);
1469         scsi_autopm_put_device(STp->device);
1470         scsi_tape_put(STp);
1471
1472         return result;
1473 }
1474 \f
1475 /* The checks common to both reading and writing */
1476 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1477 {
1478         ssize_t retval = 0;
1479
1480         /*
1481          * If we are in the middle of error recovery, don't let anyone
1482          * else try and use this device.  Also, if error recovery fails, it
1483          * may try and take the device offline, in which case all further
1484          * access to the device is prohibited.
1485          */
1486         if (!scsi_block_when_processing_errors(STp->device)) {
1487                 retval = (-ENXIO);
1488                 goto out;
1489         }
1490
1491         if (STp->ready != ST_READY) {
1492                 if (STp->ready == ST_NO_TAPE)
1493                         retval = (-ENOMEDIUM);
1494                 else
1495                         retval = (-EIO);
1496                 goto out;
1497         }
1498
1499         if (! STp->modes[STp->current_mode].defined) {
1500                 retval = (-ENXIO);
1501                 goto out;
1502         }
1503
1504
1505         /*
1506          * If there was a bus reset, block further access
1507          * to this device.
1508          */
1509         if (STp->pos_unknown) {
1510                 retval = (-EIO);
1511                 goto out;
1512         }
1513
1514         if (count == 0)
1515                 goto out;
1516
1517         DEB(
1518         if (!STp->in_use) {
1519                 st_printk(ST_DEB_MSG, STp,
1520                           "Incorrect device.\n");
1521                 retval = (-EIO);
1522                 goto out;
1523         } ) /* end DEB */
1524
1525         if (STp->can_partitions &&
1526             (retval = switch_partition(STp)) < 0)
1527                 goto out;
1528
1529         if (STp->block_size == 0 && STp->max_block > 0 &&
1530             (count < STp->min_block || count > STp->max_block)) {
1531                 retval = (-EINVAL);
1532                 goto out;
1533         }
1534
1535         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1536             !do_door_lock(STp, 1))
1537                 STp->door_locked = ST_LOCKED_AUTO;
1538
1539  out:
1540         return retval;
1541 }
1542
1543
1544 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1545                            size_t count, int is_read)
1546 {
1547         int i, bufsize, retval = 0;
1548         struct st_buffer *STbp = STp->buffer;
1549
1550         if (is_read)
1551                 i = STp->try_dio_now && try_rdio;
1552         else
1553                 i = STp->try_dio_now && try_wdio;
1554
1555         if (i && ((unsigned long)buf & queue_dma_alignment(
1556                                         STp->device->request_queue)) == 0) {
1557                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1558                                        count, (is_read ? READ : WRITE));
1559                 if (i > 0) {
1560                         STbp->do_dio = i;
1561                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1562                 }
1563                 else
1564                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1565                 STbp->sg_segs = STbp->do_dio;
1566                 DEB(
1567                      if (STbp->do_dio) {
1568                         STp->nbr_dio++;
1569                         STp->nbr_pages += STbp->do_dio;
1570                      }
1571                 )
1572         } else
1573                 STbp->do_dio = 0;
1574         DEB( STp->nbr_requests++; )
1575
1576         if (!STbp->do_dio) {
1577                 if (STp->block_size)
1578                         bufsize = STp->block_size > st_fixed_buffer_size ?
1579                                 STp->block_size : st_fixed_buffer_size;
1580                 else {
1581                         bufsize = count;
1582                         /* Make sure that data from previous user is not leaked even if
1583                            HBA does not return correct residual */
1584                         if (is_read && STp->sili && !STbp->cleared)
1585                                 clear_buffer(STbp);
1586                 }
1587
1588                 if (bufsize > STbp->buffer_size &&
1589                     !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1590                         st_printk(KERN_WARNING, STp,
1591                                   "Can't allocate %d byte tape buffer.\n",
1592                                   bufsize);
1593                         retval = (-EOVERFLOW);
1594                         goto out;
1595                 }
1596                 if (STp->block_size)
1597                         STbp->buffer_blocks = bufsize / STp->block_size;
1598         }
1599
1600  out:
1601         return retval;
1602 }
1603
1604
1605 /* Can be called more than once after each setup_buffer() */
1606 static void release_buffering(struct scsi_tape *STp, int is_read)
1607 {
1608         struct st_buffer *STbp;
1609
1610         STbp = STp->buffer;
1611         if (STbp->do_dio) {
1612                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1613                 STbp->do_dio = 0;
1614                 STbp->sg_segs = 0;
1615         }
1616 }
1617
1618
1619 /* Write command */
1620 static ssize_t
1621 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1622 {
1623         ssize_t total;
1624         ssize_t i, do_count, blks, transfer;
1625         ssize_t retval;
1626         int undone, retry_eot = 0, scode;
1627         int async_write;
1628         unsigned char cmd[MAX_COMMAND_SIZE];
1629         const char __user *b_point;
1630         struct st_request *SRpnt = NULL;
1631         struct scsi_tape *STp = filp->private_data;
1632         struct st_modedef *STm;
1633         struct st_partstat *STps;
1634         struct st_buffer *STbp;
1635
1636         if (mutex_lock_interruptible(&STp->lock))
1637                 return -ERESTARTSYS;
1638
1639         retval = rw_checks(STp, filp, count);
1640         if (retval || count == 0)
1641                 goto out;
1642
1643         /* Write must be integral number of blocks */
1644         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1645                 st_printk(KERN_WARNING, STp,
1646                           "Write not multiple of tape block size.\n");
1647                 retval = (-EINVAL);
1648                 goto out;
1649         }
1650
1651         STm = &(STp->modes[STp->current_mode]);
1652         STps = &(STp->ps[STp->partition]);
1653
1654         if (STp->write_prot) {
1655                 retval = (-EACCES);
1656                 goto out;
1657         }
1658
1659
1660         if (STps->rw == ST_READING) {
1661                 retval = flush_buffer(STp, 0);
1662                 if (retval)
1663                         goto out;
1664                 STps->rw = ST_WRITING;
1665         } else if (STps->rw != ST_WRITING &&
1666                    STps->drv_file == 0 && STps->drv_block == 0) {
1667                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1668                         goto out;
1669                 if (STm->default_compression != ST_DONT_TOUCH &&
1670                     !(STp->compression_changed)) {
1671                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1672                                 st_printk(KERN_WARNING, STp,
1673                                           "Can't set default compression.\n");
1674                                 if (modes_defined) {
1675                                         retval = (-EINVAL);
1676                                         goto out;
1677                                 }
1678                         }
1679                 }
1680         }
1681
1682         STbp = STp->buffer;
1683         i = write_behind_check(STp);
1684         if (i) {
1685                 if (i == -ENOSPC)
1686                         STps->eof = ST_EOM_OK;
1687                 else
1688                         STps->eof = ST_EOM_ERROR;
1689         }
1690
1691         if (STps->eof == ST_EOM_OK) {
1692                 STps->eof = ST_EOD_1;  /* allow next write */
1693                 retval = (-ENOSPC);
1694                 goto out;
1695         }
1696         else if (STps->eof == ST_EOM_ERROR) {
1697                 retval = (-EIO);
1698                 goto out;
1699         }
1700
1701         /* Check the buffer readability in cases where copy_user might catch
1702            the problems after some tape movement. */
1703         if (STp->block_size != 0 &&
1704             !STbp->do_dio &&
1705             (copy_from_user(&i, buf, 1) != 0 ||
1706              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1707                 retval = (-EFAULT);
1708                 goto out;
1709         }
1710
1711         retval = setup_buffering(STp, buf, count, 0);
1712         if (retval)
1713                 goto out;
1714
1715         total = count;
1716
1717         memset(cmd, 0, MAX_COMMAND_SIZE);
1718         cmd[0] = WRITE_6;
1719         cmd[1] = (STp->block_size != 0);
1720
1721         STps->rw = ST_WRITING;
1722
1723         b_point = buf;
1724         while (count > 0 && !retry_eot) {
1725
1726                 if (STbp->do_dio) {
1727                         do_count = count;
1728                 }
1729                 else {
1730                         if (STp->block_size == 0)
1731                                 do_count = count;
1732                         else {
1733                                 do_count = STbp->buffer_blocks * STp->block_size -
1734                                         STbp->buffer_bytes;
1735                                 if (do_count > count)
1736                                         do_count = count;
1737                         }
1738
1739                         i = append_to_buffer(b_point, STbp, do_count);
1740                         if (i) {
1741                                 retval = i;
1742                                 goto out;
1743                         }
1744                 }
1745                 count -= do_count;
1746                 b_point += do_count;
1747
1748                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1749                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1750
1751                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1752                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1753                     STbp->buffer_bytes < STbp->buffer_size) {
1754                         STp->dirty = 1;
1755                         /* Don't write a buffer that is not full enough. */
1756                         if (!async_write && count == 0)
1757                                 break;
1758                 }
1759
1760         retry_write:
1761                 if (STp->block_size == 0)
1762                         blks = transfer = do_count;
1763                 else {
1764                         if (!STbp->do_dio)
1765                                 blks = STbp->buffer_bytes;
1766                         else
1767                                 blks = do_count;
1768                         blks /= STp->block_size;
1769                         transfer = blks * STp->block_size;
1770                 }
1771                 cmd[2] = blks >> 16;
1772                 cmd[3] = blks >> 8;
1773                 cmd[4] = blks;
1774
1775                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1776                                    STp->device->request_queue->rq_timeout,
1777                                    MAX_WRITE_RETRIES, !async_write);
1778                 if (!SRpnt) {
1779                         retval = STbp->syscall_result;
1780                         goto out;
1781                 }
1782                 if (async_write && !STbp->syscall_result) {
1783                         STbp->writing = transfer;
1784                         STp->dirty = !(STbp->writing ==
1785                                        STbp->buffer_bytes);
1786                         SRpnt = NULL;  /* Prevent releasing this request! */
1787                         DEB( STp->write_pending = 1; )
1788                         break;
1789                 }
1790
1791                 if (STbp->syscall_result != 0) {
1792                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1793
1794                         DEBC_printk(STp, "Error on write:\n");
1795                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1796                                 scode = cmdstatp->sense_hdr.sense_key;
1797                                 if (cmdstatp->remainder_valid)
1798                                         undone = (int)cmdstatp->uremainder64;
1799                                 else if (STp->block_size == 0 &&
1800                                          scode == VOLUME_OVERFLOW)
1801                                         undone = transfer;
1802                                 else
1803                                         undone = 0;
1804                                 if (STp->block_size != 0)
1805                                         undone *= STp->block_size;
1806                                 if (undone <= do_count) {
1807                                         /* Only data from this write is not written */
1808                                         count += undone;
1809                                         b_point -= undone;
1810                                         do_count -= undone;
1811                                         if (STp->block_size)
1812                                                 blks = (transfer - undone) / STp->block_size;
1813                                         STps->eof = ST_EOM_OK;
1814                                         /* Continue in fixed block mode if all written
1815                                            in this request but still something left to write
1816                                            (retval left to zero)
1817                                         */
1818                                         if (STp->block_size == 0 ||
1819                                             undone > 0 || count == 0)
1820                                                 retval = (-ENOSPC); /* EOM within current request */
1821                                         DEBC_printk(STp, "EOM with %d "
1822                                                     "bytes unwritten.\n",
1823                                                     (int)count);
1824                                 } else {
1825                                         /* EOT within data buffered earlier (possible only
1826                                            in fixed block mode without direct i/o) */
1827                                         if (!retry_eot && !cmdstatp->deferred &&
1828                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1829                                                 move_buffer_data(STp->buffer, transfer - undone);
1830                                                 retry_eot = 1;
1831                                                 if (STps->drv_block >= 0) {
1832                                                         STps->drv_block += (transfer - undone) /
1833                                                                 STp->block_size;
1834                                                 }
1835                                                 STps->eof = ST_EOM_OK;
1836                                                 DEBC_printk(STp, "Retry "
1837                                                             "write of %d "
1838                                                             "bytes at EOM.\n",
1839                                                             STp->buffer->buffer_bytes);
1840                                                 goto retry_write;
1841                                         }
1842                                         else {
1843                                                 /* Either error within data buffered by driver or
1844                                                    failed retry */
1845                                                 count -= do_count;
1846                                                 blks = do_count = 0;
1847                                                 STps->eof = ST_EOM_ERROR;
1848                                                 STps->drv_block = (-1); /* Too cautious? */
1849                                                 retval = (-EIO);        /* EOM for old data */
1850                                                 DEBC_printk(STp, "EOM with "
1851                                                             "lost data.\n");
1852                                         }
1853                                 }
1854                         } else {
1855                                 count += do_count;
1856                                 STps->drv_block = (-1);         /* Too cautious? */
1857                                 retval = STbp->syscall_result;
1858                         }
1859
1860                 }
1861
1862                 if (STps->drv_block >= 0) {
1863                         if (STp->block_size == 0)
1864                                 STps->drv_block += (do_count > 0);
1865                         else
1866                                 STps->drv_block += blks;
1867                 }
1868
1869                 STbp->buffer_bytes = 0;
1870                 STp->dirty = 0;
1871
1872                 if (retval || retry_eot) {
1873                         if (count < total)
1874                                 retval = total - count;
1875                         goto out;
1876                 }
1877         }
1878
1879         if (STps->eof == ST_EOD_1)
1880                 STps->eof = ST_EOM_OK;
1881         else if (STps->eof != ST_EOM_OK)
1882                 STps->eof = ST_NOEOF;
1883         retval = total - count;
1884
1885  out:
1886         if (SRpnt != NULL)
1887                 st_release_request(SRpnt);
1888         release_buffering(STp, 0);
1889         mutex_unlock(&STp->lock);
1890
1891         return retval;
1892 }
1893 \f
1894 /* Read data from the tape. Returns zero in the normal case, one if the
1895    eof status has changed, and the negative error code in case of a
1896    fatal error. Otherwise updates the buffer and the eof state.
1897
1898    Does release user buffer mapping if it is set.
1899 */
1900 static long read_tape(struct scsi_tape *STp, long count,
1901                       struct st_request ** aSRpnt)
1902 {
1903         int transfer, blks, bytes;
1904         unsigned char cmd[MAX_COMMAND_SIZE];
1905         struct st_request *SRpnt;
1906         struct st_modedef *STm;
1907         struct st_partstat *STps;
1908         struct st_buffer *STbp;
1909         int retval = 0;
1910
1911         if (count == 0)
1912                 return 0;
1913
1914         STm = &(STp->modes[STp->current_mode]);
1915         STps = &(STp->ps[STp->partition]);
1916         if (STps->eof == ST_FM_HIT)
1917                 return 1;
1918         STbp = STp->buffer;
1919
1920         if (STp->block_size == 0)
1921                 blks = bytes = count;
1922         else {
1923                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1924                         blks = (STp->buffer)->buffer_blocks;
1925                         bytes = blks * STp->block_size;
1926                 } else {
1927                         bytes = count;
1928                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1929                                 bytes = (STp->buffer)->buffer_size;
1930                         blks = bytes / STp->block_size;
1931                         bytes = blks * STp->block_size;
1932                 }
1933         }
1934
1935         memset(cmd, 0, MAX_COMMAND_SIZE);
1936         cmd[0] = READ_6;
1937         cmd[1] = (STp->block_size != 0);
1938         if (!cmd[1] && STp->sili)
1939                 cmd[1] |= 2;
1940         cmd[2] = blks >> 16;
1941         cmd[3] = blks >> 8;
1942         cmd[4] = blks;
1943
1944         SRpnt = *aSRpnt;
1945         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1946                            STp->device->request_queue->rq_timeout,
1947                            MAX_RETRIES, 1);
1948         release_buffering(STp, 1);
1949         *aSRpnt = SRpnt;
1950         if (!SRpnt)
1951                 return STbp->syscall_result;
1952
1953         STbp->read_pointer = 0;
1954         STps->at_sm = 0;
1955
1956         /* Something to check */
1957         if (STbp->syscall_result) {
1958                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1959
1960                 retval = 1;
1961                 DEBC_printk(STp,
1962                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1963                             SRpnt->sense[0], SRpnt->sense[1],
1964                             SRpnt->sense[2], SRpnt->sense[3],
1965                             SRpnt->sense[4], SRpnt->sense[5],
1966                             SRpnt->sense[6], SRpnt->sense[7]);
1967                 if (cmdstatp->have_sense) {
1968
1969                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1970                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1971
1972                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1973                                 /* Compute the residual count */
1974                                 if (cmdstatp->remainder_valid)
1975                                         transfer = (int)cmdstatp->uremainder64;
1976                                 else
1977                                         transfer = 0;
1978                                 if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1979                                         if (STp->block_size == 0)
1980                                                 transfer = bytes;
1981                                         /* Some drives set ILI with MEDIUM ERROR */
1982                                         cmdstatp->flags &= ~SENSE_ILI;
1983                                 }
1984
1985                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1986                                         if (STp->block_size == 0 &&
1987                                             transfer < 0) {
1988                                                 st_printk(KERN_NOTICE, STp,
1989                                                           "Failed to read %d "
1990                                                           "byte block with %d "
1991                                                           "byte transfer.\n",
1992                                                           bytes - transfer,
1993                                                           bytes);
1994                                                 if (STps->drv_block >= 0)
1995                                                         STps->drv_block += 1;
1996                                                 STbp->buffer_bytes = 0;
1997                                                 return (-ENOMEM);
1998                                         } else if (STp->block_size == 0) {
1999                                                 STbp->buffer_bytes = bytes - transfer;
2000                                         } else {
2001                                                 st_release_request(SRpnt);
2002                                                 SRpnt = *aSRpnt = NULL;
2003                                                 if (transfer == blks) { /* We did not get anything, error */
2004                                                         st_printk(KERN_NOTICE, STp,
2005                                                                   "Incorrect "
2006                                                                   "block size.\n");
2007                                                         if (STps->drv_block >= 0)
2008                                                                 STps->drv_block += blks - transfer + 1;
2009                                                         st_int_ioctl(STp, MTBSR, 1);
2010                                                         return (-EIO);
2011                                                 }
2012                                                 /* We have some data, deliver it */
2013                                                 STbp->buffer_bytes = (blks - transfer) *
2014                                                     STp->block_size;
2015                                                 DEBC_printk(STp, "ILI but "
2016                                                             "enough data "
2017                                                             "received %ld "
2018                                                             "%d.\n", count,
2019                                                             STbp->buffer_bytes);
2020                                                 if (STps->drv_block >= 0)
2021                                                         STps->drv_block += 1;
2022                                                 if (st_int_ioctl(STp, MTBSR, 1))
2023                                                         return (-EIO);
2024                                         }
2025                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
2026                                         if (STps->eof != ST_FM_HIT)
2027                                                 STps->eof = ST_FM_HIT;
2028                                         else
2029                                                 STps->eof = ST_EOD_2;
2030                                         if (STp->block_size == 0)
2031                                                 STbp->buffer_bytes = 0;
2032                                         else
2033                                                 STbp->buffer_bytes =
2034                                                     bytes - transfer * STp->block_size;
2035                                         DEBC_printk(STp, "EOF detected (%d "
2036                                                     "bytes read).\n",
2037                                                     STbp->buffer_bytes);
2038                                 } else if (cmdstatp->flags & SENSE_EOM) {
2039                                         if (STps->eof == ST_FM)
2040                                                 STps->eof = ST_EOD_1;
2041                                         else
2042                                                 STps->eof = ST_EOM_OK;
2043                                         if (STp->block_size == 0)
2044                                                 STbp->buffer_bytes = bytes - transfer;
2045                                         else
2046                                                 STbp->buffer_bytes =
2047                                                     bytes - transfer * STp->block_size;
2048
2049                                         DEBC_printk(STp, "EOM detected (%d "
2050                                                     "bytes read).\n",
2051                                                     STbp->buffer_bytes);
2052                                 }
2053                         }
2054                         /* end of EOF, EOM, ILI test */
2055                         else {  /* nonzero sense key */
2056                                 DEBC_printk(STp, "Tape error while reading.\n");
2057                                 STps->drv_block = (-1);
2058                                 if (STps->eof == ST_FM &&
2059                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2060                                         DEBC_printk(STp, "Zero returned for "
2061                                                     "first BLANK CHECK "
2062                                                     "after EOF.\n");
2063                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
2064                                 } else  /* Some other extended sense code */
2065                                         retval = (-EIO);
2066                         }
2067
2068                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2069                                 STbp->buffer_bytes = 0;
2070                 }
2071                 /* End of extended sense test */
2072                 else {          /* Non-extended sense */
2073                         retval = STbp->syscall_result;
2074                 }
2075
2076         }
2077         /* End of error handling */
2078         else {                  /* Read successful */
2079                 STbp->buffer_bytes = bytes;
2080                 if (STp->sili) /* In fixed block mode residual is always zero here */
2081                         STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2082         }
2083
2084         if (STps->drv_block >= 0) {
2085                 if (STp->block_size == 0)
2086                         STps->drv_block++;
2087                 else
2088                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
2089         }
2090         return retval;
2091 }
2092 \f
2093
2094 /* Read command */
2095 static ssize_t
2096 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2097 {
2098         ssize_t total;
2099         ssize_t retval = 0;
2100         ssize_t i, transfer;
2101         int special, do_dio = 0;
2102         struct st_request *SRpnt = NULL;
2103         struct scsi_tape *STp = filp->private_data;
2104         struct st_modedef *STm;
2105         struct st_partstat *STps;
2106         struct st_buffer *STbp = STp->buffer;
2107
2108         if (mutex_lock_interruptible(&STp->lock))
2109                 return -ERESTARTSYS;
2110
2111         retval = rw_checks(STp, filp, count);
2112         if (retval || count == 0)
2113                 goto out;
2114
2115         STm = &(STp->modes[STp->current_mode]);
2116         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2117                 if (!STm->do_read_ahead) {
2118                         retval = (-EINVAL);     /* Read must be integral number of blocks */
2119                         goto out;
2120                 }
2121                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2122         }
2123
2124         STps = &(STp->ps[STp->partition]);
2125         if (STps->rw == ST_WRITING) {
2126                 retval = flush_buffer(STp, 0);
2127                 if (retval)
2128                         goto out;
2129                 STps->rw = ST_READING;
2130         }
2131         DEB(
2132         if (debugging && STps->eof != ST_NOEOF)
2133                 st_printk(ST_DEB_MSG, STp,
2134                           "EOF/EOM flag up (%d). Bytes %d\n",
2135                           STps->eof, STbp->buffer_bytes);
2136         ) /* end DEB */
2137
2138         retval = setup_buffering(STp, buf, count, 1);
2139         if (retval)
2140                 goto out;
2141         do_dio = STbp->do_dio;
2142
2143         if (STbp->buffer_bytes == 0 &&
2144             STps->eof >= ST_EOD_1) {
2145                 if (STps->eof < ST_EOD) {
2146                         STps->eof += 1;
2147                         retval = 0;
2148                         goto out;
2149                 }
2150                 retval = (-EIO);        /* EOM or Blank Check */
2151                 goto out;
2152         }
2153
2154         if (do_dio) {
2155                 /* Check the buffer writability before any tape movement. Don't alter
2156                    buffer data. */
2157                 if (copy_from_user(&i, buf, 1) != 0 ||
2158                     copy_to_user(buf, &i, 1) != 0 ||
2159                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
2160                     copy_to_user(buf + count - 1, &i, 1) != 0) {
2161                         retval = (-EFAULT);
2162                         goto out;
2163                 }
2164         }
2165
2166         STps->rw = ST_READING;
2167
2168
2169         /* Loop until enough data in buffer or a special condition found */
2170         for (total = 0, special = 0; total < count && !special;) {
2171
2172                 /* Get new data if the buffer is empty */
2173                 if (STbp->buffer_bytes == 0) {
2174                         special = read_tape(STp, count - total, &SRpnt);
2175                         if (special < 0) {      /* No need to continue read */
2176                                 retval = special;
2177                                 goto out;
2178                         }
2179                 }
2180
2181                 /* Move the data from driver buffer to user buffer */
2182                 if (STbp->buffer_bytes > 0) {
2183                         DEB(
2184                         if (debugging && STps->eof != ST_NOEOF)
2185                                 st_printk(ST_DEB_MSG, STp,
2186                                           "EOF up (%d). Left %d, needed %d.\n",
2187                                           STps->eof, STbp->buffer_bytes,
2188                                           (int)(count - total));
2189                         ) /* end DEB */
2190                         transfer = STbp->buffer_bytes < count - total ?
2191                             STbp->buffer_bytes : count - total;
2192                         if (!do_dio) {
2193                                 i = from_buffer(STbp, buf, transfer);
2194                                 if (i) {
2195                                         retval = i;
2196                                         goto out;
2197                                 }
2198                         }
2199                         buf += transfer;
2200                         total += transfer;
2201                 }
2202
2203                 if (STp->block_size == 0)
2204                         break;  /* Read only one variable length block */
2205
2206         }                       /* for (total = 0, special = 0;
2207                                    total < count && !special; ) */
2208
2209         /* Change the eof state if no data from tape or buffer */
2210         if (total == 0) {
2211                 if (STps->eof == ST_FM_HIT) {
2212                         STps->eof = ST_FM;
2213                         STps->drv_block = 0;
2214                         if (STps->drv_file >= 0)
2215                                 STps->drv_file++;
2216                 } else if (STps->eof == ST_EOD_1) {
2217                         STps->eof = ST_EOD_2;
2218                         STps->drv_block = 0;
2219                         if (STps->drv_file >= 0)
2220                                 STps->drv_file++;
2221                 } else if (STps->eof == ST_EOD_2)
2222                         STps->eof = ST_EOD;
2223         } else if (STps->eof == ST_FM)
2224                 STps->eof = ST_NOEOF;
2225         retval = total;
2226
2227  out:
2228         if (SRpnt != NULL) {
2229                 st_release_request(SRpnt);
2230                 SRpnt = NULL;
2231         }
2232         if (do_dio) {
2233                 release_buffering(STp, 1);
2234                 STbp->buffer_bytes = 0;
2235         }
2236         mutex_unlock(&STp->lock);
2237
2238         return retval;
2239 }
2240 \f
2241
2242
2243 DEB(
2244 /* Set the driver options */
2245 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2246 {
2247         if (debugging) {
2248                 st_printk(KERN_INFO, STp,
2249                           "Mode %d options: buffer writes: %d, "
2250                           "async writes: %d, read ahead: %d\n",
2251                           STp->current_mode, STm->do_buffer_writes,
2252                           STm->do_async_writes, STm->do_read_ahead);
2253                 st_printk(KERN_INFO, STp,
2254                           "    can bsr: %d, two FMs: %d, "
2255                           "fast mteom: %d, auto lock: %d,\n",
2256                           STp->can_bsr, STp->two_fm, STp->fast_mteom,
2257                           STp->do_auto_lock);
2258                 st_printk(KERN_INFO, STp,
2259                           "    defs for wr: %d, no block limits: %d, "
2260                           "partitions: %d, s2 log: %d\n",
2261                           STm->defaults_for_writes, STp->omit_blklims,
2262                           STp->can_partitions, STp->scsi2_logical);
2263                 st_printk(KERN_INFO, STp,
2264                           "    sysv: %d nowait: %d sili: %d "
2265                           "nowait_filemark: %d\n",
2266                           STm->sysv, STp->immediate, STp->sili,
2267                           STp->immediate_filemark);
2268                 st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2269         }
2270 }
2271         )
2272
2273
2274 static int st_set_options(struct scsi_tape *STp, long options)
2275 {
2276         int value;
2277         long code;
2278         struct st_modedef *STm;
2279         struct cdev *cd0, *cd1;
2280         struct device *d0, *d1;
2281
2282         STm = &(STp->modes[STp->current_mode]);
2283         if (!STm->defined) {
2284                 cd0 = STm->cdevs[0];
2285                 cd1 = STm->cdevs[1];
2286                 d0  = STm->devs[0];
2287                 d1  = STm->devs[1];
2288                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2289                 STm->cdevs[0] = cd0;
2290                 STm->cdevs[1] = cd1;
2291                 STm->devs[0]  = d0;
2292                 STm->devs[1]  = d1;
2293                 modes_defined = 1;
2294                 DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2295                             STp->current_mode);
2296         }
2297
2298         code = options & MT_ST_OPTIONS;
2299         if (code == MT_ST_BOOLEANS) {
2300                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2301                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2302                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2303                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2304                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2305                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2306                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2307                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2308                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2309                 if ((STp->device)->scsi_level >= SCSI_2)
2310                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2311                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2312                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2313                 STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2314                 STm->sysv = (options & MT_ST_SYSV) != 0;
2315                 STp->sili = (options & MT_ST_SILI) != 0;
2316                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2317                      st_log_options(STp, STm); )
2318         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2319                 value = (code == MT_ST_SETBOOLEANS);
2320                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2321                         STm->do_buffer_writes = value;
2322                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2323                         STm->do_async_writes = value;
2324                 if ((options & MT_ST_DEF_WRITES) != 0)
2325                         STm->defaults_for_writes = value;
2326                 if ((options & MT_ST_READ_AHEAD) != 0)
2327                         STm->do_read_ahead = value;
2328                 if ((options & MT_ST_TWO_FM) != 0)
2329                         STp->two_fm = value;
2330                 if ((options & MT_ST_FAST_MTEOM) != 0)
2331                         STp->fast_mteom = value;
2332                 if ((options & MT_ST_AUTO_LOCK) != 0)
2333                         STp->do_auto_lock = value;
2334                 if ((options & MT_ST_CAN_BSR) != 0)
2335                         STp->can_bsr = value;
2336                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2337                         STp->omit_blklims = value;
2338                 if ((STp->device)->scsi_level >= SCSI_2 &&
2339                     (options & MT_ST_CAN_PARTITIONS) != 0)
2340                         STp->can_partitions = value;
2341                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2342                         STp->scsi2_logical = value;
2343                 if ((options & MT_ST_NOWAIT) != 0)
2344                         STp->immediate = value;
2345                 if ((options & MT_ST_NOWAIT_EOF) != 0)
2346                         STp->immediate_filemark = value;
2347                 if ((options & MT_ST_SYSV) != 0)
2348                         STm->sysv = value;
2349                 if ((options & MT_ST_SILI) != 0)
2350                         STp->sili = value;
2351                 DEB(
2352                 if ((options & MT_ST_DEBUGGING) != 0)
2353                         debugging = value;
2354                         st_log_options(STp, STm); )
2355         } else if (code == MT_ST_WRITE_THRESHOLD) {
2356                 /* Retained for compatibility */
2357         } else if (code == MT_ST_DEF_BLKSIZE) {
2358                 value = (options & ~MT_ST_OPTIONS);
2359                 if (value == ~MT_ST_OPTIONS) {
2360                         STm->default_blksize = (-1);
2361                         DEBC_printk(STp, "Default block size disabled.\n");
2362                 } else {
2363                         STm->default_blksize = value;
2364                         DEBC_printk(STp,"Default block size set to "
2365                                     "%d bytes.\n", STm->default_blksize);
2366                         if (STp->ready == ST_READY) {
2367                                 STp->blksize_changed = 0;
2368                                 set_mode_densblk(STp, STm);
2369                         }
2370                 }
2371         } else if (code == MT_ST_TIMEOUTS) {
2372                 value = (options & ~MT_ST_OPTIONS);
2373                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2374                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2375                         DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2376                                     (value & ~MT_ST_SET_LONG_TIMEOUT));
2377                 } else {
2378                         blk_queue_rq_timeout(STp->device->request_queue,
2379                                              value * HZ);
2380                         DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2381                                     value);
2382                 }
2383         } else if (code == MT_ST_SET_CLN) {
2384                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2385                 if (value != 0 &&
2386                         (value < EXTENDED_SENSE_START ||
2387                                 value >= SCSI_SENSE_BUFFERSIZE))
2388                         return (-EINVAL);
2389                 STp->cln_mode = value;
2390                 STp->cln_sense_mask = (options >> 8) & 0xff;
2391                 STp->cln_sense_value = (options >> 16) & 0xff;
2392                 st_printk(KERN_INFO, STp,
2393                           "Cleaning request mode %d, mask %02x, value %02x\n",
2394                           value, STp->cln_sense_mask, STp->cln_sense_value);
2395         } else if (code == MT_ST_DEF_OPTIONS) {
2396                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2397                 value = (options & MT_ST_CLEAR_DEFAULT);
2398                 if (code == MT_ST_DEF_DENSITY) {
2399                         if (value == MT_ST_CLEAR_DEFAULT) {
2400                                 STm->default_density = (-1);
2401                                 DEBC_printk(STp,
2402                                             "Density default disabled.\n");
2403                         } else {
2404                                 STm->default_density = value & 0xff;
2405                                 DEBC_printk(STp, "Density default set to %x\n",
2406                                             STm->default_density);
2407                                 if (STp->ready == ST_READY) {
2408                                         STp->density_changed = 0;
2409                                         set_mode_densblk(STp, STm);
2410                                 }
2411                         }
2412                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2413                         if (value == MT_ST_CLEAR_DEFAULT) {
2414                                 STp->default_drvbuffer = 0xff;
2415                                 DEBC_printk(STp,
2416                                             "Drive buffer default disabled.\n");
2417                         } else {
2418                                 STp->default_drvbuffer = value & 7;
2419                                 DEBC_printk(STp,
2420                                             "Drive buffer default set to %x\n",
2421                                             STp->default_drvbuffer);
2422                                 if (STp->ready == ST_READY)
2423                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2424                         }
2425                 } else if (code == MT_ST_DEF_COMPRESSION) {
2426                         if (value == MT_ST_CLEAR_DEFAULT) {
2427                                 STm->default_compression = ST_DONT_TOUCH;
2428                                 DEBC_printk(STp,
2429                                             "Compression default disabled.\n");
2430                         } else {
2431                                 if ((value & 0xff00) != 0) {
2432                                         STp->c_algo = (value & 0xff00) >> 8;
2433                                         DEBC_printk(STp, "Compression "
2434                                                     "algorithm set to 0x%x.\n",
2435                                                     STp->c_algo);
2436                                 }
2437                                 if ((value & 0xff) != 0xff) {
2438                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2439                                         DEBC_printk(STp, "Compression default "
2440                                                     "set to %x\n",
2441                                                     (value & 1));
2442                                         if (STp->ready == ST_READY) {
2443                                                 STp->compression_changed = 0;
2444                                                 st_compression(STp, (STm->default_compression == ST_YES));
2445                                         }
2446                                 }
2447                         }
2448                 }
2449         } else
2450                 return (-EIO);
2451
2452         return 0;
2453 }
2454 \f
2455 #define MODE_HEADER_LENGTH  4
2456
2457 /* Mode header and page byte offsets */
2458 #define MH_OFF_DATA_LENGTH     0
2459 #define MH_OFF_MEDIUM_TYPE     1
2460 #define MH_OFF_DEV_SPECIFIC    2
2461 #define MH_OFF_BDESCS_LENGTH   3
2462 #define MP_OFF_PAGE_NBR        0
2463 #define MP_OFF_PAGE_LENGTH     1
2464
2465 /* Mode header and page bit masks */
2466 #define MH_BIT_WP              0x80
2467 #define MP_MSK_PAGE_NBR        0x3f
2468
2469 /* Don't return block descriptors */
2470 #define MODE_SENSE_OMIT_BDESCS 0x08
2471
2472 #define MODE_SELECT_PAGE_FORMAT 0x10
2473
2474 /* Read a mode page into the tape buffer. The block descriptors are included
2475    if incl_block_descs is true. The page control is ored to the page number
2476    parameter, if necessary. */
2477 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2478 {
2479         unsigned char cmd[MAX_COMMAND_SIZE];
2480         struct st_request *SRpnt;
2481
2482         memset(cmd, 0, MAX_COMMAND_SIZE);
2483         cmd[0] = MODE_SENSE;
2484         if (omit_block_descs)
2485                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2486         cmd[2] = page;
2487         cmd[4] = 255;
2488
2489         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2490                            STp->device->request_queue->rq_timeout, 0, 1);
2491         if (SRpnt == NULL)
2492                 return (STp->buffer)->syscall_result;
2493
2494         st_release_request(SRpnt);
2495
2496         return STp->buffer->syscall_result;
2497 }
2498
2499
2500 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2501    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2502 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2503 {
2504         int pgo;
2505         unsigned char cmd[MAX_COMMAND_SIZE];
2506         struct st_request *SRpnt;
2507         int timeout;
2508
2509         memset(cmd, 0, MAX_COMMAND_SIZE);
2510         cmd[0] = MODE_SELECT;
2511         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2512         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2513         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2514
2515         /* Clear reserved fields */
2516         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2517         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2518         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2519         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2520
2521         timeout = slow ?
2522                 STp->long_timeout : STp->device->request_queue->rq_timeout;
2523         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2524                            timeout, 0, 1);
2525         if (SRpnt == NULL)
2526                 return (STp->buffer)->syscall_result;
2527
2528         st_release_request(SRpnt);
2529
2530         return STp->buffer->syscall_result;
2531 }
2532
2533
2534 #define COMPRESSION_PAGE        0x0f
2535 #define COMPRESSION_PAGE_LENGTH 16
2536
2537 #define CP_OFF_DCE_DCC          2
2538 #define CP_OFF_C_ALGO           7
2539
2540 #define DCE_MASK  0x80
2541 #define DCC_MASK  0x40
2542 #define RED_MASK  0x60
2543
2544
2545 /* Control the compression with mode page 15. Algorithm not changed if zero.
2546
2547    The block descriptors are read and written because Sony SDT-7000 does not
2548    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2549    Including block descriptors should not cause any harm to other drives. */
2550
2551 static int st_compression(struct scsi_tape * STp, int state)
2552 {
2553         int retval;
2554         int mpoffs;  /* Offset to mode page start */
2555         unsigned char *b_data = (STp->buffer)->b_data;
2556
2557         if (STp->ready != ST_READY)
2558                 return (-EIO);
2559
2560         /* Read the current page contents */
2561         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2562         if (retval) {
2563                 DEBC_printk(STp, "Compression mode page not supported.\n");
2564                 return (-EIO);
2565         }
2566
2567         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2568         DEBC_printk(STp, "Compression state is %d.\n",
2569                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2570
2571         /* Check if compression can be changed */
2572         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2573                 DEBC_printk(STp, "Compression not supported.\n");
2574                 return (-EIO);
2575         }
2576
2577         /* Do the change */
2578         if (state) {
2579                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2580                 if (STp->c_algo != 0)
2581                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2582         }
2583         else {
2584                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2585                 if (STp->c_algo != 0)
2586                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2587         }
2588
2589         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2590         if (retval) {
2591                 DEBC_printk(STp, "Compression change failed.\n");
2592                 return (-EIO);
2593         }
2594         DEBC_printk(STp, "Compression state changed to %d.\n", state);
2595
2596         STp->compression_changed = 1;
2597         return 0;
2598 }
2599
2600
2601 /* Process the load and unload commands (does unload if the load code is zero) */
2602 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2603 {
2604         int retval = (-EIO), timeout;
2605         unsigned char cmd[MAX_COMMAND_SIZE];
2606         struct st_partstat *STps;
2607         struct st_request *SRpnt;
2608
2609         if (STp->ready != ST_READY && !load_code) {
2610                 if (STp->ready == ST_NO_TAPE)
2611                         return (-ENOMEDIUM);
2612                 else
2613                         return (-EIO);
2614         }
2615
2616         memset(cmd, 0, MAX_COMMAND_SIZE);
2617         cmd[0] = START_STOP;
2618         if (load_code)
2619                 cmd[4] |= 1;
2620         /*
2621          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2622          */
2623         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2624             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2625                 DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2626                             (cmd[4]) ? "" : "un",
2627                             load_code - MT_ST_HPLOADER_OFFSET);
2628                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2629         }
2630         if (STp->immediate) {
2631                 cmd[1] = 1;     /* Don't wait for completion */
2632                 timeout = STp->device->request_queue->rq_timeout;
2633         }
2634         else
2635                 timeout = STp->long_timeout;
2636
2637         DEBC(
2638                 if (!load_code)
2639                         st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2640                 else
2641                         st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2642                 );
2643
2644         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2645                            timeout, MAX_RETRIES, 1);
2646         if (!SRpnt)
2647                 return (STp->buffer)->syscall_result;
2648
2649         retval = (STp->buffer)->syscall_result;
2650         st_release_request(SRpnt);
2651
2652         if (!retval) {  /* SCSI command successful */
2653
2654                 if (!load_code) {
2655                         STp->rew_at_close = 0;
2656                         STp->ready = ST_NO_TAPE;
2657                 }
2658                 else {
2659                         STp->rew_at_close = STp->autorew_dev;
2660                         retval = check_tape(STp, filp);
2661                         if (retval > 0)
2662                                 retval = 0;
2663                 }
2664         }
2665         else {
2666                 STps = &(STp->ps[STp->partition]);
2667                 STps->drv_file = STps->drv_block = (-1);
2668         }
2669
2670         return retval;
2671 }
2672 \f
2673 #if DEBUG
2674 #define ST_DEB_FORWARD  0
2675 #define ST_DEB_BACKWARD 1
2676 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2677 {
2678         s32 sc;
2679
2680         if (!debugging)
2681                 return;
2682
2683         sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2684         sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2685         if (direction)
2686                 sc = -sc;
2687         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2688                   direction ? "backward" : "forward", sc, units);
2689 }
2690 #else
2691 #define ST_DEB_FORWARD  0
2692 #define ST_DEB_BACKWARD 1
2693 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2694 #endif
2695
2696
2697 /* Internal ioctl function */
2698 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2699 {
2700         int timeout;
2701         long ltmp;
2702         int ioctl_result;
2703         int chg_eof = 1;
2704         unsigned char cmd[MAX_COMMAND_SIZE];
2705         struct st_request *SRpnt;
2706         struct st_partstat *STps;
2707         int fileno, blkno, at_sm, undone;
2708         int datalen = 0, direction = DMA_NONE;
2709
2710         WARN_ON(STp->buffer->do_dio != 0);
2711         if (STp->ready != ST_READY) {
2712                 if (STp->ready == ST_NO_TAPE)
2713                         return (-ENOMEDIUM);
2714                 else
2715                         return (-EIO);
2716         }
2717         timeout = STp->long_timeout;
2718         STps = &(STp->ps[STp->partition]);
2719         fileno = STps->drv_file;
2720         blkno = STps->drv_block;
2721         at_sm = STps->at_sm;
2722
2723         memset(cmd, 0, MAX_COMMAND_SIZE);
2724         switch (cmd_in) {
2725         case MTFSFM:
2726                 chg_eof = 0;    /* Changed from the FSF after this */
2727                 /* fall through */
2728         case MTFSF:
2729                 cmd[0] = SPACE;
2730                 cmd[1] = 0x01;  /* Space FileMarks */
2731                 cmd[2] = (arg >> 16);
2732                 cmd[3] = (arg >> 8);
2733                 cmd[4] = arg;
2734                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2735                 if (fileno >= 0)
2736                         fileno += arg;
2737                 blkno = 0;
2738                 at_sm &= (arg == 0);
2739                 break;
2740         case MTBSFM:
2741                 chg_eof = 0;    /* Changed from the FSF after this */
2742                 /* fall through */
2743         case MTBSF:
2744                 cmd[0] = SPACE;
2745                 cmd[1] = 0x01;  /* Space FileMarks */
2746                 ltmp = (-arg);
2747                 cmd[2] = (ltmp >> 16);
2748                 cmd[3] = (ltmp >> 8);
2749                 cmd[4] = ltmp;
2750                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2751                 if (fileno >= 0)
2752                         fileno -= arg;
2753                 blkno = (-1);   /* We can't know the block number */
2754                 at_sm &= (arg == 0);
2755                 break;
2756         case MTFSR:
2757                 cmd[0] = SPACE;
2758                 cmd[1] = 0x00;  /* Space Blocks */
2759                 cmd[2] = (arg >> 16);
2760                 cmd[3] = (arg >> 8);
2761                 cmd[4] = arg;
2762                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2763                 if (blkno >= 0)
2764                         blkno += arg;
2765                 at_sm &= (arg == 0);
2766                 break;
2767         case MTBSR:
2768                 cmd[0] = SPACE;
2769                 cmd[1] = 0x00;  /* Space Blocks */
2770                 ltmp = (-arg);
2771                 cmd[2] = (ltmp >> 16);
2772                 cmd[3] = (ltmp >> 8);
2773                 cmd[4] = ltmp;
2774                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2775                 if (blkno >= 0)
2776                         blkno -= arg;
2777                 at_sm &= (arg == 0);
2778                 break;
2779         case MTFSS:
2780                 cmd[0] = SPACE;
2781                 cmd[1] = 0x04;  /* Space Setmarks */
2782                 cmd[2] = (arg >> 16);
2783                 cmd[3] = (arg >> 8);
2784                 cmd[4] = arg;
2785                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2786                 if (arg != 0) {
2787                         blkno = fileno = (-1);
2788                         at_sm = 1;
2789                 }
2790                 break;
2791         case MTBSS:
2792                 cmd[0] = SPACE;
2793                 cmd[1] = 0x04;  /* Space Setmarks */
2794                 ltmp = (-arg);
2795                 cmd[2] = (ltmp >> 16);
2796                 cmd[3] = (ltmp >> 8);
2797                 cmd[4] = ltmp;
2798                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2799                 if (arg != 0) {
2800                         blkno = fileno = (-1);
2801                         at_sm = 1;
2802                 }
2803                 break;
2804         case MTWEOF:
2805         case MTWEOFI:
2806         case MTWSM:
2807                 if (STp->write_prot)
2808                         return (-EACCES);
2809                 cmd[0] = WRITE_FILEMARKS;
2810                 if (cmd_in == MTWSM)
2811                         cmd[1] = 2;
2812                 if (cmd_in == MTWEOFI ||
2813                     (cmd_in == MTWEOF && STp->immediate_filemark))
2814                         cmd[1] |= 1;
2815                 cmd[2] = (arg >> 16);
2816                 cmd[3] = (arg >> 8);
2817                 cmd[4] = arg;
2818                 timeout = STp->device->request_queue->rq_timeout;
2819                 DEBC(
2820                         if (cmd_in != MTWSM)
2821                                 st_printk(ST_DEB_MSG, STp,
2822                                           "Writing %d filemarks.\n",
2823                                           cmd[2] * 65536 +
2824                                           cmd[3] * 256 +
2825                                           cmd[4]);
2826                         else
2827                                 st_printk(ST_DEB_MSG, STp,
2828                                           "Writing %d setmarks.\n",
2829                                           cmd[2] * 65536 +
2830                                           cmd[3] * 256 +
2831                                           cmd[4]);
2832                 )
2833                 if (fileno >= 0)
2834                         fileno += arg;
2835                 blkno = 0;
2836                 at_sm = (cmd_in == MTWSM);
2837                 break;
2838         case MTREW:
2839                 cmd[0] = REZERO_UNIT;
2840                 if (STp->immediate) {
2841                         cmd[1] = 1;     /* Don't wait for completion */
2842                         timeout = STp->device->request_queue->rq_timeout;
2843                 }
2844                 DEBC_printk(STp, "Rewinding tape.\n");
2845                 fileno = blkno = at_sm = 0;
2846                 break;
2847         case MTNOP:
2848                 DEBC_printk(STp, "No op on tape.\n");
2849                 return 0;       /* Should do something ? */
2850                 break;
2851         case MTRETEN:
2852                 cmd[0] = START_STOP;
2853                 if (STp->immediate) {
2854                         cmd[1] = 1;     /* Don't wait for completion */
2855                         timeout = STp->device->request_queue->rq_timeout;
2856                 }
2857                 cmd[4] = 3;
2858                 DEBC_printk(STp, "Retensioning tape.\n");
2859                 fileno = blkno = at_sm = 0;
2860                 break;
2861         case MTEOM:
2862                 if (!STp->fast_mteom) {
2863                         /* space to the end of tape */
2864                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2865                         fileno = STps->drv_file;
2866                         if (STps->eof >= ST_EOD_1)
2867                                 return 0;
2868                         /* The next lines would hide the number of spaced FileMarks
2869                            That's why I inserted the previous lines. I had no luck
2870                            with detecting EOM with FSF, so we go now to EOM.
2871                            Joerg Weule */
2872                 } else
2873                         fileno = (-1);
2874                 cmd[0] = SPACE;
2875                 cmd[1] = 3;
2876                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2877                 blkno = -1;
2878                 at_sm = 0;
2879                 break;
2880         case MTERASE:
2881                 if (STp->write_prot)
2882                         return (-EACCES);
2883                 cmd[0] = ERASE;
2884                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2885                 if (STp->immediate) {
2886                         cmd[1] |= 2;    /* Don't wait for completion */
2887                         timeout = STp->device->request_queue->rq_timeout;
2888                 }
2889                 else
2890                         timeout = STp->long_timeout * 8;
2891
2892                 DEBC_printk(STp, "Erasing tape.\n");
2893                 fileno = blkno = at_sm = 0;
2894                 break;
2895         case MTSETBLK:          /* Set block length */
2896         case MTSETDENSITY:      /* Set tape density */
2897         case MTSETDRVBUFFER:    /* Set drive buffering */
2898         case SET_DENS_AND_BLK:  /* Set density and block size */
2899                 chg_eof = 0;
2900                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2901                         return (-EIO);  /* Not allowed if data in buffer */
2902                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2903                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2904                     STp->max_block > 0 &&
2905                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2906                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2907                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2908                         return (-EINVAL);
2909                 }
2910                 cmd[0] = MODE_SELECT;
2911                 if ((STp->use_pf & USE_PF))
2912                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2913                 cmd[4] = datalen = 12;
2914                 direction = DMA_TO_DEVICE;
2915
2916                 memset((STp->buffer)->b_data, 0, 12);
2917                 if (cmd_in == MTSETDRVBUFFER)
2918                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2919                 else
2920                         (STp->buffer)->b_data[2] =
2921                             STp->drv_buffer << 4;
2922                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2923                 if (cmd_in == MTSETDENSITY) {
2924                         (STp->buffer)->b_data[4] = arg;
2925                         STp->density_changed = 1;       /* At least we tried ;-) */
2926                 } else if (cmd_in == SET_DENS_AND_BLK)
2927                         (STp->buffer)->b_data[4] = arg >> 24;
2928                 else
2929                         (STp->buffer)->b_data[4] = STp->density;
2930                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2931                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2932                         if (cmd_in == MTSETBLK)
2933                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2934                 } else
2935                         ltmp = STp->block_size;
2936                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2937                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2938                 (STp->buffer)->b_data[11] = ltmp;
2939                 timeout = STp->device->request_queue->rq_timeout;
2940                 DEBC(
2941                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2942                                 st_printk(ST_DEB_MSG, STp,
2943                                           "Setting block size to %d bytes.\n",
2944                                           (STp->buffer)->b_data[9] * 65536 +
2945                                           (STp->buffer)->b_data[10] * 256 +
2946                                           (STp->buffer)->b_data[11]);
2947                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2948                                 st_printk(ST_DEB_MSG, STp,
2949                                           "Setting density code to %x.\n",
2950                                           (STp->buffer)->b_data[4]);
2951                         if (cmd_in == MTSETDRVBUFFER)
2952                                 st_printk(ST_DEB_MSG, STp,
2953                                           "Setting drive buffer code to %d.\n",
2954                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2955                 )
2956                 break;
2957         default:
2958                 return (-ENOSYS);
2959         }
2960
2961         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2962                            timeout, MAX_RETRIES, 1);
2963         if (!SRpnt)
2964                 return (STp->buffer)->syscall_result;
2965
2966         ioctl_result = (STp->buffer)->syscall_result;
2967
2968         if (!ioctl_result) {    /* SCSI command successful */
2969                 st_release_request(SRpnt);
2970                 SRpnt = NULL;
2971                 STps->drv_block = blkno;
2972                 STps->drv_file = fileno;
2973                 STps->at_sm = at_sm;
2974
2975                 if (cmd_in == MTBSFM)
2976                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2977                 else if (cmd_in == MTFSFM)
2978                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2979
2980                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2981                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2982                         if (STp->block_size != 0) {
2983                                 (STp->buffer)->buffer_blocks =
2984                                     (STp->buffer)->buffer_size / STp->block_size;
2985                         }
2986                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2987                         if (cmd_in == SET_DENS_AND_BLK)
2988                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2989                 } else if (cmd_in == MTSETDRVBUFFER)
2990                         STp->drv_buffer = (arg & 7);
2991                 else if (cmd_in == MTSETDENSITY)
2992                         STp->density = arg;
2993
2994                 if (cmd_in == MTEOM)
2995                         STps->eof = ST_EOD;
2996                 else if (cmd_in == MTFSF)
2997                         STps->eof = ST_FM;
2998                 else if (chg_eof)
2999                         STps->eof = ST_NOEOF;
3000
3001                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
3002                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3003         } else { /* SCSI command was not completely successful. Don't return
3004                     from this block without releasing the SCSI command block! */
3005                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3006
3007                 if (cmdstatp->flags & SENSE_EOM) {
3008                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3009                             cmd_in != MTBSR && cmd_in != MTBSS)
3010                                 STps->eof = ST_EOM_OK;
3011                         STps->drv_block = 0;
3012                 }
3013
3014                 if (cmdstatp->remainder_valid)
3015                         undone = (int)cmdstatp->uremainder64;
3016                 else
3017                         undone = 0;
3018
3019                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3020                     cmdstatp->have_sense &&
3021                     (cmdstatp->flags & SENSE_EOM)) {
3022                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3023                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3024                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3025                                 STps->eof = ST_NOEOF;
3026                         } else {  /* Writing EOF(s) failed */
3027                                 if (fileno >= 0)
3028                                         fileno -= undone;
3029                                 if (undone < arg)
3030                                         STps->eof = ST_NOEOF;
3031                         }
3032                         STps->drv_file = fileno;
3033                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3034                         if (fileno >= 0)
3035                                 STps->drv_file = fileno - undone;
3036                         else
3037                                 STps->drv_file = fileno;
3038                         STps->drv_block = -1;
3039                         STps->eof = ST_NOEOF;
3040                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3041                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3042                                 undone = (-undone);
3043                         if (STps->drv_file >= 0)
3044                                 STps->drv_file = fileno + undone;
3045                         STps->drv_block = 0;
3046                         STps->eof = ST_NOEOF;
3047                 } else if (cmd_in == MTFSR) {
3048                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3049                                 if (STps->drv_file >= 0)
3050                                         STps->drv_file++;
3051                                 STps->drv_block = 0;
3052                                 STps->eof = ST_FM;
3053                         } else {
3054                                 if (blkno >= undone)
3055                                         STps->drv_block = blkno - undone;
3056                                 else
3057                                         STps->drv_block = (-1);
3058                                 STps->eof = ST_NOEOF;
3059                         }
3060                 } else if (cmd_in == MTBSR) {
3061                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3062                                 STps->drv_file--;
3063                                 STps->drv_block = (-1);
3064                         } else {
3065                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3066                                         undone = (-undone);
3067                                 if (STps->drv_block >= 0)
3068                                         STps->drv_block = blkno + undone;
3069                         }
3070                         STps->eof = ST_NOEOF;
3071                 } else if (cmd_in == MTEOM) {
3072                         STps->drv_file = (-1);
3073                         STps->drv_block = (-1);
3074                         STps->eof = ST_EOD;
3075                 } else if (cmd_in == MTSETBLK ||
3076                            cmd_in == MTSETDENSITY ||
3077                            cmd_in == MTSETDRVBUFFER ||
3078                            cmd_in == SET_DENS_AND_BLK) {
3079                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3080                             !(STp->use_pf & PF_TESTED)) {
3081                                 /* Try the other possible state of Page Format if not
3082                                    already tried */
3083                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3084                                 st_release_request(SRpnt);
3085                                 SRpnt = NULL;
3086                                 return st_int_ioctl(STp, cmd_in, arg);
3087                         }
3088                 } else if (chg_eof)
3089                         STps->eof = ST_NOEOF;
3090
3091                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3092                         STps->eof = ST_EOD;
3093
3094                 st_release_request(SRpnt);
3095                 SRpnt = NULL;
3096         }
3097
3098         return ioctl_result;
3099 }
3100 \f
3101
3102 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3103    structure. */
3104
3105 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3106                         int logical)
3107 {
3108         int result;
3109         unsigned char scmd[MAX_COMMAND_SIZE];
3110         struct st_request *SRpnt;
3111
3112         if (STp->ready != ST_READY)
3113                 return (-EIO);
3114
3115         memset(scmd, 0, MAX_COMMAND_SIZE);
3116         if ((STp->device)->scsi_level < SCSI_2) {
3117                 scmd[0] = QFA_REQUEST_BLOCK;
3118                 scmd[4] = 3;
3119         } else {
3120                 scmd[0] = READ_POSITION;
3121                 if (!logical && !STp->scsi2_logical)
3122                         scmd[1] = 1;
3123         }
3124         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3125                            STp->device->request_queue->rq_timeout,
3126                            MAX_READY_RETRIES, 1);
3127         if (!SRpnt)
3128                 return (STp->buffer)->syscall_result;
3129
3130         if ((STp->buffer)->syscall_result != 0 ||
3131             (STp->device->scsi_level >= SCSI_2 &&
3132              ((STp->buffer)->b_data[0] & 4) != 0)) {
3133                 *block = *partition = 0;
3134                 DEBC_printk(STp, " Can't read tape position.\n");
3135                 result = (-EIO);
3136         } else {
3137                 result = 0;
3138                 if ((STp->device)->scsi_level < SCSI_2) {
3139                         *block = ((STp->buffer)->b_data[0] << 16)
3140                             + ((STp->buffer)->b_data[1] << 8)
3141                             + (STp->buffer)->b_data[2];
3142                         *partition = 0;
3143                 } else {
3144                         *block = ((STp->buffer)->b_data[4] << 24)
3145                             + ((STp->buffer)->b_data[5] << 16)
3146                             + ((STp->buffer)->b_data[6] << 8)
3147                             + (STp->buffer)->b_data[7];
3148                         *partition = (STp->buffer)->b_data[1];
3149                         if (((STp->buffer)->b_data[0] & 0x80) &&
3150                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3151                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3152                 }
3153                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3154                             *block, *partition);
3155         }
3156         st_release_request(SRpnt);
3157         SRpnt = NULL;
3158
3159         return result;
3160 }
3161
3162
3163 /* Set the tape block and partition. Negative partition means that only the
3164    block should be set in vendor specific way. */
3165 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3166                         int logical)
3167 {
3168         struct st_partstat *STps;
3169         int result, p;
3170         unsigned int blk;
3171         int timeout;
3172         unsigned char scmd[MAX_COMMAND_SIZE];
3173         struct st_request *SRpnt;
3174
3175         if (STp->ready != ST_READY)
3176                 return (-EIO);
3177         timeout = STp->long_timeout;
3178         STps = &(STp->ps[STp->partition]);
3179
3180         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3181                     block, partition);
3182         DEB(if (partition < 0)
3183                 return (-EIO); )
3184
3185         /* Update the location at the partition we are leaving */
3186         if ((!STp->can_partitions && partition != 0) ||
3187             partition >= ST_NBR_PARTITIONS)
3188                 return (-EINVAL);
3189         if (partition != STp->partition) {
3190                 if (get_location(STp, &blk, &p, 1))
3191                         STps->last_block_valid = 0;
3192                 else {
3193                         STps->last_block_valid = 1;
3194                         STps->last_block_visited = blk;
3195                         DEBC_printk(STp, "Visited block %d for "
3196                                     "partition %d saved.\n",
3197                                     blk, STp->partition);
3198                 }
3199         }
3200
3201         memset(scmd, 0, MAX_COMMAND_SIZE);
3202         if ((STp->device)->scsi_level < SCSI_2) {
3203                 scmd[0] = QFA_SEEK_BLOCK;
3204                 scmd[2] = (block >> 16);
3205                 scmd[3] = (block >> 8);
3206                 scmd[4] = block;
3207                 scmd[5] = 0;
3208         } else {
3209                 scmd[0] = SEEK_10;
3210                 scmd[3] = (block >> 24);
3211                 scmd[4] = (block >> 16);
3212                 scmd[5] = (block >> 8);
3213                 scmd[6] = block;
3214                 if (!logical && !STp->scsi2_logical)
3215                         scmd[1] = 4;
3216                 if (STp->partition != partition) {
3217                         scmd[1] |= 2;
3218                         scmd[8] = partition;
3219                         DEBC_printk(STp, "Trying to change partition "
3220                                     "from %d to %d\n", STp->partition,
3221                                     partition);
3222                 }
3223         }
3224         if (STp->immediate) {
3225                 scmd[1] |= 1;           /* Don't wait for completion */
3226                 timeout = STp->device->request_queue->rq_timeout;
3227         }
3228
3229         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3230                            timeout, MAX_READY_RETRIES, 1);
3231         if (!SRpnt)
3232                 return (STp->buffer)->syscall_result;
3233
3234         STps->drv_block = STps->drv_file = (-1);
3235         STps->eof = ST_NOEOF;
3236         if ((STp->buffer)->syscall_result != 0) {
3237                 result = (-EIO);
3238                 if (STp->can_partitions &&
3239                     (STp->device)->scsi_level >= SCSI_2 &&
3240                     (p = find_partition(STp)) >= 0)
3241                         STp->partition = p;
3242         } else {
3243                 if (STp->can_partitions) {
3244                         STp->partition = partition;
3245                         STps = &(STp->ps[partition]);
3246                         if (!STps->last_block_valid ||
3247                             STps->last_block_visited != block) {
3248                                 STps->at_sm = 0;
3249                                 STps->rw = ST_IDLE;
3250                         }
3251                 } else
3252                         STps->at_sm = 0;
3253                 if (block == 0)
3254                         STps->drv_block = STps->drv_file = 0;
3255                 result = 0;
3256         }
3257
3258         st_release_request(SRpnt);
3259         SRpnt = NULL;
3260
3261         return result;
3262 }
3263
3264
3265 /* Find the current partition number for the drive status. Called from open and
3266    returns either partition number of negative error code. */
3267 static int find_partition(struct scsi_tape *STp)
3268 {
3269         int i, partition;
3270         unsigned int block;
3271
3272         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3273                 return i;
3274         if (partition >= ST_NBR_PARTITIONS)
3275                 return (-EIO);
3276         return partition;
3277 }
3278
3279
3280 /* Change the partition if necessary */
3281 static int switch_partition(struct scsi_tape *STp)
3282 {
3283         struct st_partstat *STps;
3284
3285         if (STp->partition == STp->new_partition)
3286                 return 0;
3287         STps = &(STp->ps[STp->new_partition]);
3288         if (!STps->last_block_valid)
3289                 STps->last_block_visited = 0;
3290         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3291 }
3292 \f
3293 /* Functions for reading and writing the medium partition mode page. */
3294
3295 #define PART_PAGE   0x11
3296 #define PART_PAGE_FIXED_LENGTH 8
3297
3298 #define PP_OFF_MAX_ADD_PARTS   2
3299 #define PP_OFF_NBR_ADD_PARTS   3
3300 #define PP_OFF_FLAGS           4
3301 #define PP_OFF_PART_UNITS      6
3302 #define PP_OFF_RESERVED        7
3303
3304 #define PP_BIT_IDP             0x20
3305 #define PP_BIT_FDP             0x80
3306 #define PP_MSK_PSUM_MB         0x10
3307 #define PP_MSK_PSUM_UNITS      0x18
3308 #define PP_MSK_POFM            0x04
3309
3310 /* Get the number of partitions on the tape. As a side effect reads the
3311    mode page into the tape buffer. */
3312 static int nbr_partitions(struct scsi_tape *STp)
3313 {
3314         int result;
3315
3316         if (STp->ready != ST_READY)
3317                 return (-EIO);
3318
3319         result = read_mode_page(STp, PART_PAGE, 1);
3320
3321         if (result) {
3322                 DEBC_printk(STp, "Can't read medium partition page.\n");
3323                 result = (-EIO);
3324         } else {
3325                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3326                                               PP_OFF_NBR_ADD_PARTS] + 1;
3327                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3328         }
3329
3330         return result;
3331 }
3332
3333
3334 static int format_medium(struct scsi_tape *STp, int format)
3335 {
3336         int result = 0;
3337         int timeout = STp->long_timeout;
3338         unsigned char scmd[MAX_COMMAND_SIZE];
3339         struct st_request *SRpnt;
3340
3341         memset(scmd, 0, MAX_COMMAND_SIZE);
3342         scmd[0] = FORMAT_UNIT;
3343         scmd[2] = format;
3344         if (STp->immediate) {
3345                 scmd[1] |= 1;           /* Don't wait for completion */
3346                 timeout = STp->device->request_queue->rq_timeout;
3347         }
3348         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3349         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3350                            timeout, MAX_RETRIES, 1);
3351         if (!SRpnt)
3352                 result = STp->buffer->syscall_result;
3353         return result;
3354 }
3355
3356
3357 /* Partition the tape into two partitions if size > 0 or one partition if
3358    size == 0.
3359
3360    The block descriptors are read and written because Sony SDT-7000 does not
3361    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3362
3363    My HP C1533A drive returns only one partition size field. This is used to
3364    set the size of partition 1. There is no size field for the default partition.
3365    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3366    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3367    The following algorithm is used to accommodate both drives: if the number of
3368    partition size fields is greater than the maximum number of additional partitions
3369    in the mode page, the second field is used. Otherwise the first field is used.
3370
3371    For Seagate DDS drives the page length must be 8 when no partitions is defined
3372    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3373    is acceptable also to some other old drives and enforced if the first partition
3374    size field is used for the first additional partition size.
3375
3376    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3377  */
3378 static int partition_tape(struct scsi_tape *STp, int size)
3379 {
3380         int result;
3381         int target_partition;
3382         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3383         int pgo, psd_cnt, psdo;
3384         int psum = PP_MSK_PSUM_MB, units = 0;
3385         unsigned char *bp;
3386
3387         result = read_mode_page(STp, PART_PAGE, 0);
3388         if (result) {
3389                 DEBC_printk(STp, "Can't read partition mode page.\n");
3390                 return result;
3391         }
3392         target_partition = 1;
3393         if (size < 0) {
3394                 target_partition = 0;
3395                 size = -size;
3396         }
3397
3398         /* The mode page is in the buffer. Let's modify it and write it. */
3399         bp = (STp->buffer)->b_data;
3400         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3401         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3402                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3403
3404         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3405
3406         if (scsi3) {
3407                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3408                 if (needs_format && size == 0) {
3409                         /* No need to write the mode page when clearing
3410                          *  partitioning
3411                          */
3412                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3413                         result = format_medium(STp, 0);
3414                         goto out;
3415                 }
3416                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3417                         psd_cnt = 2;
3418                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3419                         /* Use units scaling for large partitions if the device
3420                          * suggests it and no precision lost. Required for IBM
3421                          * TS1140/50 drives that don't support MB units.
3422                          */
3423                         if (size >= 1000 && (size % 1000) == 0) {
3424                                 size /= 1000;
3425                                 psum = PP_MSK_PSUM_UNITS;
3426                                 units = 9; /* GB */
3427                         }
3428                 }
3429                 /* Try it anyway if too large to specify in MB */
3430                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3431                         size /= 1000;
3432                         psum = PP_MSK_PSUM_UNITS;
3433                         units = 9;  /* GB */
3434                 }
3435         }
3436
3437         if (size >= 65535 ||  /* Does not fit into two bytes */
3438             (target_partition == 0 && psd_cnt < 2)) {
3439                 result = -EINVAL;
3440                 goto out;
3441         }
3442
3443         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3444         /* The second condition is for HP DDS which use only one partition size
3445          * descriptor
3446          */
3447         if (target_partition > 0 &&
3448             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3449              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3450                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3451                 psdo += 2;
3452         }
3453         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3454
3455         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3456                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3457                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3458
3459         if (size == 0) {
3460                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3461                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3462                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3463                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3464         } else {
3465                 bp[psdo] = (size >> 8) & 0xff;
3466                 bp[psdo + 1] = size & 0xff;
3467                 if (target_partition == 0)
3468                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3469                 bp[pgo + 3] = 1;
3470                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3471                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3472                 DEBC_printk(STp,
3473                             "Formatting tape with two partitions (%i = %d MB).\n",
3474                             target_partition, units > 0 ? size * 1000 : size);
3475         }
3476         bp[pgo + PP_OFF_PART_UNITS] = 0;
3477         bp[pgo + PP_OFF_RESERVED] = 0;
3478         if (size != 1 || units != 0) {
3479                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3480                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3481                 bp[pgo + PP_OFF_PART_UNITS] = units;
3482         } else
3483                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3484                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3485         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3486
3487         result = write_mode_page(STp, PART_PAGE, 1);
3488
3489         if (!result && needs_format)
3490                 result = format_medium(STp, 1);
3491
3492         if (result) {
3493                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3494                 result = (-EIO);
3495         }
3496
3497 out:
3498         return result;
3499 }
3500 \f
3501
3502
3503 /* The ioctl command */
3504 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3505 {
3506         int i, cmd_nr, cmd_type, bt;
3507         int retval = 0;
3508         unsigned int blk;
3509         struct scsi_tape *STp = file->private_data;
3510         struct st_modedef *STm;
3511         struct st_partstat *STps;
3512         void __user *p = (void __user *)arg;
3513
3514         if (mutex_lock_interruptible(&STp->lock))
3515                 return -ERESTARTSYS;
3516
3517         DEB(
3518         if (debugging && !STp->in_use) {
3519                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3520                 retval = (-EIO);
3521                 goto out;
3522         } ) /* end DEB */
3523
3524         STm = &(STp->modes[STp->current_mode]);
3525         STps = &(STp->ps[STp->partition]);
3526
3527         /*
3528          * If we are in the middle of error recovery, don't let anyone
3529          * else try and use this device.  Also, if error recovery fails, it
3530          * may try and take the device offline, in which case all further
3531          * access to the device is prohibited.
3532          */
3533         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3534                         file->f_flags & O_NDELAY);
3535         if (retval)
3536                 goto out;
3537
3538         cmd_type = _IOC_TYPE(cmd_in);
3539         cmd_nr = _IOC_NR(cmd_in);
3540
3541         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3542                 struct mtop mtc;
3543
3544                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3545                         retval = (-EINVAL);
3546                         goto out;
3547                 }
3548
3549                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3550                 if (i) {
3551                         retval = (-EFAULT);
3552                         goto out;
3553                 }
3554
3555                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3556                         st_printk(KERN_WARNING, STp,
3557                                   "MTSETDRVBUFFER only allowed for root.\n");
3558                         retval = (-EPERM);
3559                         goto out;
3560                 }
3561                 if (!STm->defined &&
3562                     (mtc.mt_op != MTSETDRVBUFFER &&
3563                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3564                         retval = (-ENXIO);
3565                         goto out;
3566                 }
3567
3568                 if (!STp->pos_unknown) {
3569
3570                         if (STps->eof == ST_FM_HIT) {
3571                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3572                                     mtc.mt_op == MTEOM) {
3573                                         mtc.mt_count -= 1;
3574                                         if (STps->drv_file >= 0)
3575                                                 STps->drv_file += 1;
3576                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3577                                         mtc.mt_count += 1;
3578                                         if (STps->drv_file >= 0)
3579                                                 STps->drv_file += 1;
3580                                 }
3581                         }
3582
3583                         if (mtc.mt_op == MTSEEK) {
3584                                 /* Old position must be restored if partition will be
3585                                    changed */
3586                                 i = !STp->can_partitions ||
3587                                     (STp->new_partition != STp->partition);
3588                         } else {
3589                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3590                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3591                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3592                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3593                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3594                                     mtc.mt_op == MTCOMPRESSION;
3595                         }
3596                         i = flush_buffer(STp, i);
3597                         if (i < 0) {
3598                                 retval = i;
3599                                 goto out;
3600                         }
3601                         if (STps->rw == ST_WRITING &&
3602                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3603                              mtc.mt_op == MTSEEK ||
3604                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3605                                 i = st_int_ioctl(STp, MTWEOF, 1);
3606                                 if (i < 0) {
3607                                         retval = i;
3608                                         goto out;
3609                                 }
3610                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3611                                         mtc.mt_count++;
3612                                 STps->rw = ST_IDLE;
3613                              }
3614
3615                 } else {
3616                         /*
3617                          * If there was a bus reset, block further access
3618                          * to this device.  If the user wants to rewind the tape,
3619                          * then reset the flag and allow access again.
3620                          */
3621                         if (mtc.mt_op != MTREW &&
3622                             mtc.mt_op != MTOFFL &&
3623                             mtc.mt_op != MTRETEN &&
3624                             mtc.mt_op != MTERASE &&
3625                             mtc.mt_op != MTSEEK &&
3626                             mtc.mt_op != MTEOM) {
3627                                 retval = (-EIO);
3628                                 goto out;
3629                         }
3630                         reset_state(STp);
3631                         /* remove this when the midlevel properly clears was_reset */
3632                         STp->device->was_reset = 0;
3633                 }
3634
3635                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3636                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3637                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3638                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3639
3640                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3641                         do_door_lock(STp, 0);   /* Ignore result! */
3642
3643                 if (mtc.mt_op == MTSETDRVBUFFER &&
3644                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3645                         retval = st_set_options(STp, mtc.mt_count);
3646                         goto out;
3647                 }
3648
3649                 if (mtc.mt_op == MTSETPART) {
3650                         if (!STp->can_partitions ||
3651                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3652                                 retval = (-EINVAL);
3653                                 goto out;
3654                         }
3655                         if (mtc.mt_count >= STp->nbr_partitions &&
3656                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3657                                 retval = (-EIO);
3658                                 goto out;
3659                         }
3660                         if (mtc.mt_count >= STp->nbr_partitions) {
3661                                 retval = (-EINVAL);
3662                                 goto out;
3663                         }
3664                         STp->new_partition = mtc.mt_count;
3665                         retval = 0;
3666                         goto out;
3667                 }
3668
3669                 if (mtc.mt_op == MTMKPART) {
3670                         if (!STp->can_partitions) {
3671                                 retval = (-EINVAL);
3672                                 goto out;
3673                         }
3674                         i = do_load_unload(STp, file, 1);
3675                         if (i < 0) {
3676                                 retval = i;
3677                                 goto out;
3678                         }
3679                         i = partition_tape(STp, mtc.mt_count);
3680                         if (i < 0) {
3681                                 retval = i;
3682                                 goto out;
3683                         }
3684                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3685                                 STp->ps[i].rw = ST_IDLE;
3686                                 STp->ps[i].at_sm = 0;
3687                                 STp->ps[i].last_block_valid = 0;
3688                         }
3689                         STp->partition = STp->new_partition = 0;
3690                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3691                         STps->drv_block = STps->drv_file = 0;
3692                         retval = 0;
3693                         goto out;
3694                 }
3695
3696                 if (mtc.mt_op == MTSEEK) {
3697                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3698                         if (!STp->can_partitions)
3699                                 STp->ps[0].rw = ST_IDLE;
3700                         retval = i;
3701                         goto out;
3702                 }
3703
3704                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3705                         retval = do_load_unload(STp, file, 0);
3706                         goto out;
3707                 }
3708
3709                 if (mtc.mt_op == MTLOAD) {
3710                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3711                         goto out;
3712                 }
3713
3714                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3715                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3716                         goto out;
3717                 }
3718
3719                 if (STp->can_partitions && STp->ready == ST_READY &&
3720                     (i = switch_partition(STp)) < 0) {
3721                         retval = i;
3722                         goto out;
3723                 }
3724
3725                 if (mtc.mt_op == MTCOMPRESSION)
3726                         retval = st_compression(STp, (mtc.mt_count & 1));
3727                 else
3728                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3729                 goto out;
3730         }
3731         if (!STm->defined) {
3732                 retval = (-ENXIO);
3733                 goto out;
3734         }
3735
3736         if ((i = flush_buffer(STp, 0)) < 0) {
3737                 retval = i;
3738                 goto out;
3739         }
3740         if (STp->can_partitions &&
3741             (i = switch_partition(STp)) < 0) {
3742                 retval = i;
3743                 goto out;
3744         }
3745
3746         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3747                 struct mtget mt_status;
3748
3749                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3750                          retval = (-EINVAL);
3751                          goto out;
3752                 }
3753
3754                 mt_status.mt_type = STp->tape_type;
3755                 mt_status.mt_dsreg =
3756                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3757                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3758                 mt_status.mt_blkno = STps->drv_block;
3759                 mt_status.mt_fileno = STps->drv_file;
3760                 if (STp->block_size != 0) {
3761                         if (STps->rw == ST_WRITING)
3762                                 mt_status.mt_blkno +=
3763                                     (STp->buffer)->buffer_bytes / STp->block_size;
3764                         else if (STps->rw == ST_READING)
3765                                 mt_status.mt_blkno -=
3766                                         ((STp->buffer)->buffer_bytes +
3767                                          STp->block_size - 1) / STp->block_size;
3768                 }
3769
3770                 mt_status.mt_gstat = 0;
3771                 if (STp->drv_write_prot)
3772                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3773                 if (mt_status.mt_blkno == 0) {
3774                         if (mt_status.mt_fileno == 0)
3775                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3776                         else
3777                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3778                 }
3779                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3780                 mt_status.mt_resid = STp->partition;
3781                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3782                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3783                 else if (STps->eof >= ST_EOM_OK)
3784                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3785                 if (STp->density == 1)
3786                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3787                 else if (STp->density == 2)
3788                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3789                 else if (STp->density == 3)
3790                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3791                 if (STp->ready == ST_READY)
3792                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3793                 if (STp->ready == ST_NO_TAPE)
3794                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3795                 if (STps->at_sm)
3796                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3797                 if (STm->do_async_writes ||
3798                     (STm->do_buffer_writes && STp->block_size != 0) ||
3799                     STp->drv_buffer != 0)
3800                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3801                 if (STp->cleaning_req)
3802                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3803
3804                 i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3805                 if (i) {
3806                         retval = (-EFAULT);
3807                         goto out;
3808                 }
3809
3810                 STp->recover_reg = 0;           /* Clear after read */
3811                 retval = 0;
3812                 goto out;
3813         }                       /* End of MTIOCGET */
3814         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3815                 struct mtpos mt_pos;
3816                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3817                          retval = (-EINVAL);
3818                          goto out;
3819                 }
3820                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3821                         retval = i;
3822                         goto out;
3823                 }
3824                 mt_pos.mt_blkno = blk;
3825                 i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3826                 if (i)
3827                         retval = (-EFAULT);
3828                 goto out;
3829         }
3830         mutex_unlock(&STp->lock);
3831         switch (cmd_in) {
3832                 case SCSI_IOCTL_GET_IDLUN:
3833                 case SCSI_IOCTL_GET_BUS_NUMBER:
3834                         break;
3835                 default:
3836                         if ((cmd_in == SG_IO ||
3837                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3838                              cmd_in == CDROM_SEND_PACKET) &&
3839                             !capable(CAP_SYS_RAWIO))
3840                                 i = -EPERM;
3841                         else
3842                                 i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3843                                                    file->f_mode, cmd_in, p);
3844                         if (i != -ENOTTY)
3845                                 return i;
3846                         break;
3847         }
3848         retval = scsi_ioctl(STp->device, cmd_in, p);
3849         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3850                 STp->rew_at_close = 0;
3851                 STp->ready = ST_NO_TAPE;
3852         }
3853         return retval;
3854
3855  out:
3856         mutex_unlock(&STp->lock);
3857         return retval;
3858 }
3859
3860 #ifdef CONFIG_COMPAT
3861 static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3862 {
3863         struct scsi_tape *STp = file->private_data;
3864         struct scsi_device *sdev = STp->device;
3865         int ret = -ENOIOCTLCMD;
3866         if (sdev->host->hostt->compat_ioctl) {
3867
3868                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3869
3870         }
3871         return ret;
3872 }
3873 #endif
3874
3875 \f
3876
3877 /* Try to allocate a new tape buffer. Calling function must not hold
3878    dev_arr_lock. */
3879 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3880 {
3881         struct st_buffer *tb;
3882
3883         tb = kzalloc(sizeof(struct st_buffer), GFP_KERNEL);
3884         if (!tb) {
3885                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3886                 return NULL;
3887         }
3888         tb->frp_segs = 0;
3889         tb->use_sg = max_sg;
3890         tb->dma = need_dma;
3891         tb->buffer_size = 0;
3892
3893         tb->reserved_pages = kcalloc(max_sg, sizeof(struct page *),
3894                                      GFP_KERNEL);
3895         if (!tb->reserved_pages) {
3896                 kfree(tb);
3897                 return NULL;
3898         }
3899
3900         return tb;
3901 }
3902
3903
3904 /* Try to allocate enough space in the tape buffer */
3905 #define ST_MAX_ORDER 6
3906
3907 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3908 {
3909         int segs, max_segs, b_size, order, got;
3910         gfp_t priority;
3911
3912         if (new_size <= STbuffer->buffer_size)
3913                 return 1;
3914
3915         if (STbuffer->buffer_size <= PAGE_SIZE)
3916                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3917
3918         max_segs = STbuffer->use_sg;
3919
3920         priority = GFP_KERNEL | __GFP_NOWARN;
3921         if (need_dma)
3922                 priority |= GFP_DMA;
3923
3924         if (STbuffer->cleared)
3925                 priority |= __GFP_ZERO;
3926
3927         if (STbuffer->frp_segs) {
3928                 order = STbuffer->reserved_page_order;
3929                 b_size = PAGE_SIZE << order;
3930         } else {
3931                 for (b_size = PAGE_SIZE, order = 0;
3932                      order < ST_MAX_ORDER &&
3933                              max_segs * (PAGE_SIZE << order) < new_size;
3934                      order++, b_size *= 2)
3935                         ;  /* empty */
3936                 STbuffer->reserved_page_order = order;
3937         }
3938         if (max_segs * (PAGE_SIZE << order) < new_size) {
3939                 if (order == ST_MAX_ORDER)
3940                         return 0;
3941                 normalize_buffer(STbuffer);
3942                 return enlarge_buffer(STbuffer, new_size, need_dma);
3943         }
3944
3945         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3946              segs < max_segs && got < new_size;) {
3947                 struct page *page;
3948
3949                 page = alloc_pages(priority, order);
3950                 if (!page) {
3951                         DEB(STbuffer->buffer_size = got);
3952                         normalize_buffer(STbuffer);
3953                         return 0;
3954                 }
3955
3956                 STbuffer->frp_segs += 1;
3957                 got += b_size;
3958                 STbuffer->buffer_size = got;
3959                 STbuffer->reserved_pages[segs] = page;
3960                 segs++;
3961         }
3962         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3963
3964         return 1;
3965 }
3966
3967
3968 /* Make sure that no data from previous user is in the internal buffer */
3969 static void clear_buffer(struct st_buffer * st_bp)
3970 {
3971         int i;
3972
3973         for (i=0; i < st_bp->frp_segs; i++)
3974                 memset(page_address(st_bp->reserved_pages[i]), 0,
3975                        PAGE_SIZE << st_bp->reserved_page_order);
3976         st_bp->cleared = 1;
3977 }
3978
3979
3980 /* Release the extra buffer */
3981 static void normalize_buffer(struct st_buffer * STbuffer)
3982 {
3983         int i, order = STbuffer->reserved_page_order;
3984
3985         for (i = 0; i < STbuffer->frp_segs; i++) {
3986                 __free_pages(STbuffer->reserved_pages[i], order);
3987                 STbuffer->buffer_size -= (PAGE_SIZE << order);
3988         }
3989         STbuffer->frp_segs = 0;
3990         STbuffer->sg_segs = 0;
3991         STbuffer->reserved_page_order = 0;
3992         STbuffer->map_data.offset = 0;
3993 }
3994
3995
3996 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3997    negative error code. */
3998 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3999 {
4000         int i, cnt, res, offset;
4001         int length = PAGE_SIZE << st_bp->reserved_page_order;
4002
4003         for (i = 0, offset = st_bp->buffer_bytes;
4004              i < st_bp->frp_segs && offset >= length; i++)
4005                 offset -= length;
4006         if (i == st_bp->frp_segs) {     /* Should never happen */
4007                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4008                 return (-EIO);
4009         }
4010         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4011                 struct page *page = st_bp->reserved_pages[i];
4012                 cnt = length - offset < do_count ? length - offset : do_count;
4013                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4014                 if (res)
4015                         return (-EFAULT);
4016                 do_count -= cnt;
4017                 st_bp->buffer_bytes += cnt;
4018                 ubp += cnt;
4019                 offset = 0;
4020         }
4021         if (do_count) /* Should never happen */
4022                 return (-EIO);
4023
4024         return 0;
4025 }
4026
4027
4028 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4029    negative error code. */
4030 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4031 {
4032         int i, cnt, res, offset;
4033         int length = PAGE_SIZE << st_bp->reserved_page_order;
4034
4035         for (i = 0, offset = st_bp->read_pointer;
4036              i < st_bp->frp_segs && offset >= length; i++)
4037                 offset -= length;
4038         if (i == st_bp->frp_segs) {     /* Should never happen */
4039                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4040                 return (-EIO);
4041         }
4042         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4043                 struct page *page = st_bp->reserved_pages[i];
4044                 cnt = length - offset < do_count ? length - offset : do_count;
4045                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4046                 if (res)
4047                         return (-EFAULT);
4048                 do_count -= cnt;
4049                 st_bp->buffer_bytes -= cnt;
4050                 st_bp->read_pointer += cnt;
4051                 ubp += cnt;
4052                 offset = 0;
4053         }
4054         if (do_count) /* Should never happen */
4055                 return (-EIO);
4056
4057         return 0;
4058 }
4059
4060
4061 /* Move data towards start of buffer */
4062 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4063 {
4064         int src_seg, dst_seg, src_offset = 0, dst_offset;
4065         int count, total;
4066         int length = PAGE_SIZE << st_bp->reserved_page_order;
4067
4068         if (offset == 0)
4069                 return;
4070
4071         total=st_bp->buffer_bytes - offset;
4072         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4073                 src_offset = offset;
4074                 if (src_offset < length)
4075                         break;
4076                 offset -= length;
4077         }
4078
4079         st_bp->buffer_bytes = st_bp->read_pointer = total;
4080         for (dst_seg=dst_offset=0; total > 0; ) {
4081                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4082                 struct page *spage = st_bp->reserved_pages[src_seg];
4083
4084                 count = min(length - dst_offset, length - src_offset);
4085                 memmove(page_address(dpage) + dst_offset,
4086                         page_address(spage) + src_offset, count);
4087                 src_offset += count;
4088                 if (src_offset >= length) {
4089                         src_seg++;
4090                         src_offset = 0;
4091                 }
4092                 dst_offset += count;
4093                 if (dst_offset >= length) {
4094                         dst_seg++;
4095                         dst_offset = 0;
4096                 }
4097                 total -= count;
4098         }
4099 }
4100
4101 /* Validate the options from command line or module parameters */
4102 static void validate_options(void)
4103 {
4104         if (buffer_kbs > 0)
4105                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4106         if (max_sg_segs >= ST_FIRST_SG)
4107                 st_max_sg_segs = max_sg_segs;
4108 }
4109
4110 #ifndef MODULE
4111 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4112  */
4113 static int __init st_setup(char *str)
4114 {
4115         int i, len, ints[5];
4116         char *stp;
4117
4118         stp = get_options(str, ARRAY_SIZE(ints), ints);
4119
4120         if (ints[0] > 0) {
4121                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4122                         if (parms[i].val)
4123                                 *parms[i].val = ints[i + 1];
4124         } else {
4125                 while (stp != NULL) {
4126                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4127                                 len = strlen(parms[i].name);
4128                                 if (!strncmp(stp, parms[i].name, len) &&
4129                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4130                                         if (parms[i].val)
4131                                                 *parms[i].val =
4132                                                         simple_strtoul(stp + len + 1, NULL, 0);
4133                                         else
4134                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4135                                                        parms[i].name);
4136                                         break;
4137                                 }
4138                         }
4139                         if (i >= ARRAY_SIZE(parms))
4140                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4141                                         stp);
4142                         stp = strchr(stp, ',');
4143                         if (stp)
4144                                 stp++;
4145                 }
4146         }
4147
4148         validate_options();
4149
4150         return 1;
4151 }
4152
4153 __setup("st=", st_setup);
4154
4155 #endif
4156
4157 static const struct file_operations st_fops =
4158 {
4159         .owner =        THIS_MODULE,
4160         .read =         st_read,
4161         .write =        st_write,
4162         .unlocked_ioctl = st_ioctl,
4163 #ifdef CONFIG_COMPAT
4164         .compat_ioctl = st_compat_ioctl,
4165 #endif
4166         .open =         st_open,
4167         .flush =        st_flush,
4168         .release =      st_release,
4169         .llseek =       noop_llseek,
4170 };
4171
4172 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4173 {
4174         int i, error;
4175         dev_t cdev_devno;
4176         struct cdev *cdev;
4177         struct device *dev;
4178         struct st_modedef *STm = &(tape->modes[mode]);
4179         char name[10];
4180         int dev_num = tape->index;
4181
4182         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4183
4184         cdev = cdev_alloc();
4185         if (!cdev) {
4186                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4187                 error = -ENOMEM;
4188                 goto out;
4189         }
4190         cdev->owner = THIS_MODULE;
4191         cdev->ops = &st_fops;
4192         STm->cdevs[rew] = cdev;
4193
4194         error = cdev_add(cdev, cdev_devno, 1);
4195         if (error) {
4196                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4197                        rew ? "non" : "auto", mode);
4198                 pr_err("st%d: Device not attached.\n", dev_num);
4199                 goto out_free;
4200         }
4201
4202         i = mode << (4 - ST_NBR_MODE_BITS);
4203         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4204                  tape->disk->disk_name, st_formats[i]);
4205
4206         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4207                             cdev_devno, &tape->modes[mode], "%s", name);
4208         if (IS_ERR(dev)) {
4209                 pr_err("st%d: device_create failed\n", dev_num);
4210                 error = PTR_ERR(dev);
4211                 goto out_free;
4212         }
4213
4214         STm->devs[rew] = dev;
4215
4216         return 0;
4217 out_free:
4218         cdev_del(STm->cdevs[rew]);
4219 out:
4220         STm->cdevs[rew] = NULL;
4221         STm->devs[rew] = NULL;
4222         return error;
4223 }
4224
4225 static int create_cdevs(struct scsi_tape *tape)
4226 {
4227         int mode, error;
4228         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4229                 error = create_one_cdev(tape, mode, 0);
4230                 if (error)
4231                         return error;
4232                 error = create_one_cdev(tape, mode, 1);
4233                 if (error)
4234                         return error;
4235         }
4236
4237         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4238                                  &tape->modes[0].devs[0]->kobj, "tape");
4239 }
4240
4241 static void remove_cdevs(struct scsi_tape *tape)
4242 {
4243         int mode, rew;
4244         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4245         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4246                 struct st_modedef *STm = &(tape->modes[mode]);
4247                 for (rew = 0; rew < 2; rew++) {
4248                         if (STm->cdevs[rew])
4249                                 cdev_del(STm->cdevs[rew]);
4250                         if (STm->devs[rew])
4251                                 device_unregister(STm->devs[rew]);
4252                 }
4253         }
4254 }
4255
4256 static int st_probe(struct device *dev)
4257 {
4258         struct scsi_device *SDp = to_scsi_device(dev);
4259         struct gendisk *disk = NULL;
4260         struct scsi_tape *tpnt = NULL;
4261         struct st_modedef *STm;
4262         struct st_partstat *STps;
4263         struct st_buffer *buffer;
4264         int i, error;
4265         char *stp;
4266
4267         if (SDp->type != TYPE_TAPE)
4268                 return -ENODEV;
4269         if ((stp = st_incompatible(SDp))) {
4270                 sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4271                 sdev_printk(KERN_INFO, SDp,
4272                             "st: The suggested driver is %s.\n", stp);
4273                 return -ENODEV;
4274         }
4275
4276         scsi_autopm_get_device(SDp);
4277         i = queue_max_segments(SDp->request_queue);
4278         if (st_max_sg_segs < i)
4279                 i = st_max_sg_segs;
4280         buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4281         if (buffer == NULL) {
4282                 sdev_printk(KERN_ERR, SDp,
4283                             "st: Can't allocate new tape buffer. "
4284                             "Device not attached.\n");
4285                 goto out;
4286         }
4287
4288         disk = alloc_disk(1);
4289         if (!disk) {
4290                 sdev_printk(KERN_ERR, SDp,
4291                             "st: out of memory. Device not attached.\n");
4292                 goto out_buffer_free;
4293         }
4294
4295         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
4296         if (tpnt == NULL) {
4297                 sdev_printk(KERN_ERR, SDp,
4298                             "st: Can't allocate device descriptor.\n");
4299                 goto out_put_disk;
4300         }
4301         kref_init(&tpnt->kref);
4302         tpnt->disk = disk;
4303         disk->private_data = &tpnt->driver;
4304         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4305          * take queue reference that release_disk() expects. */
4306         if (!blk_get_queue(SDp->request_queue))
4307                 goto out_put_disk;
4308         disk->queue = SDp->request_queue;
4309         tpnt->driver = &st_template;
4310
4311         tpnt->device = SDp;
4312         if (SDp->scsi_level <= 2)
4313                 tpnt->tape_type = MT_ISSCSI1;
4314         else
4315                 tpnt->tape_type = MT_ISSCSI2;
4316
4317         tpnt->buffer = buffer;
4318         tpnt->buffer->last_SRpnt = NULL;
4319
4320         tpnt->inited = 0;
4321         tpnt->dirty = 0;
4322         tpnt->in_use = 0;
4323         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4324         tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4325         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4326         tpnt->density = 0;
4327         tpnt->do_auto_lock = ST_AUTO_LOCK;
4328         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4329         tpnt->can_partitions = 0;
4330         tpnt->two_fm = ST_TWO_FM;
4331         tpnt->fast_mteom = ST_FAST_MTEOM;
4332         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4333         tpnt->sili = ST_SILI;
4334         tpnt->immediate = ST_NOWAIT;
4335         tpnt->immediate_filemark = 0;
4336         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4337         tpnt->partition = 0;
4338         tpnt->new_partition = 0;
4339         tpnt->nbr_partitions = 0;
4340         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4341         tpnt->long_timeout = ST_LONG_TIMEOUT;
4342         tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4343
4344         for (i = 0; i < ST_NBR_MODES; i++) {
4345                 STm = &(tpnt->modes[i]);
4346                 STm->defined = 0;
4347                 STm->sysv = ST_SYSV;
4348                 STm->defaults_for_writes = 0;
4349                 STm->do_async_writes = ST_ASYNC_WRITES;
4350                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4351                 STm->do_read_ahead = ST_READ_AHEAD;
4352                 STm->default_compression = ST_DONT_TOUCH;
4353                 STm->default_blksize = (-1);    /* No forced size */
4354                 STm->default_density = (-1);    /* No forced density */
4355                 STm->tape = tpnt;
4356         }
4357
4358         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4359                 STps = &(tpnt->ps[i]);
4360                 STps->rw = ST_IDLE;
4361                 STps->eof = ST_NOEOF;
4362                 STps->at_sm = 0;
4363                 STps->last_block_valid = 0;
4364                 STps->drv_block = (-1);
4365                 STps->drv_file = (-1);
4366         }
4367
4368         tpnt->current_mode = 0;
4369         tpnt->modes[0].defined = 1;
4370
4371         tpnt->density_changed = tpnt->compression_changed =
4372             tpnt->blksize_changed = 0;
4373         mutex_init(&tpnt->lock);
4374
4375         idr_preload(GFP_KERNEL);
4376         spin_lock(&st_index_lock);
4377         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4378         spin_unlock(&st_index_lock);
4379         idr_preload_end();
4380         if (error < 0) {
4381                 pr_warn("st: idr allocation failed: %d\n", error);
4382                 goto out_put_queue;
4383         }
4384         tpnt->index = error;
4385         sprintf(disk->disk_name, "st%d", tpnt->index);
4386         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4387         if (tpnt->stats == NULL) {
4388                 sdev_printk(KERN_ERR, SDp,
4389                             "st: Can't allocate statistics.\n");
4390                 goto out_idr_remove;
4391         }
4392
4393         dev_set_drvdata(dev, tpnt);
4394
4395
4396         error = create_cdevs(tpnt);
4397         if (error)
4398                 goto out_remove_devs;
4399         scsi_autopm_put_device(SDp);
4400
4401         sdev_printk(KERN_NOTICE, SDp,
4402                     "Attached scsi tape %s\n", tape_name(tpnt));
4403         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4404                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4405                     queue_dma_alignment(SDp->request_queue) + 1);
4406
4407         return 0;
4408
4409 out_remove_devs:
4410         remove_cdevs(tpnt);
4411         kfree(tpnt->stats);
4412 out_idr_remove:
4413         spin_lock(&st_index_lock);
4414         idr_remove(&st_index_idr, tpnt->index);
4415         spin_unlock(&st_index_lock);
4416 out_put_queue:
4417         blk_put_queue(disk->queue);
4418 out_put_disk:
4419         put_disk(disk);
4420         kfree(tpnt);
4421 out_buffer_free:
4422         kfree(buffer);
4423 out:
4424         scsi_autopm_put_device(SDp);
4425         return -ENODEV;
4426 };
4427
4428
4429 static int st_remove(struct device *dev)
4430 {
4431         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4432         int index = tpnt->index;
4433
4434         scsi_autopm_get_device(to_scsi_device(dev));
4435         remove_cdevs(tpnt);
4436
4437         mutex_lock(&st_ref_mutex);
4438         kref_put(&tpnt->kref, scsi_tape_release);
4439         mutex_unlock(&st_ref_mutex);
4440         spin_lock(&st_index_lock);
4441         idr_remove(&st_index_idr, index);
4442         spin_unlock(&st_index_lock);
4443         return 0;
4444 }
4445
4446 /**
4447  *      scsi_tape_release - Called to free the Scsi_Tape structure
4448  *      @kref: pointer to embedded kref
4449  *
4450  *      st_ref_mutex must be held entering this routine.  Because it is
4451  *      called on last put, you should always use the scsi_tape_get()
4452  *      scsi_tape_put() helpers which manipulate the semaphore directly
4453  *      and never do a direct kref_put().
4454  **/
4455 static void scsi_tape_release(struct kref *kref)
4456 {
4457         struct scsi_tape *tpnt = to_scsi_tape(kref);
4458         struct gendisk *disk = tpnt->disk;
4459
4460         tpnt->device = NULL;
4461
4462         if (tpnt->buffer) {
4463                 normalize_buffer(tpnt->buffer);
4464                 kfree(tpnt->buffer->reserved_pages);
4465                 kfree(tpnt->buffer);
4466         }
4467
4468         disk->private_data = NULL;
4469         put_disk(disk);
4470         kfree(tpnt->stats);
4471         kfree(tpnt);
4472         return;
4473 }
4474
4475 static struct class st_sysfs_class = {
4476         .name = "scsi_tape",
4477         .dev_groups = st_dev_groups,
4478 };
4479
4480 static int __init init_st(void)
4481 {
4482         int err;
4483
4484         validate_options();
4485
4486         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4487                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4488
4489         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4490         if (debugging) {
4491                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4492                         debugging);
4493         }
4494
4495         err = class_register(&st_sysfs_class);
4496         if (err) {
4497                 pr_err("Unable register sysfs class for SCSI tapes\n");
4498                 return err;
4499         }
4500
4501         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4502                                      ST_MAX_TAPE_ENTRIES, "st");
4503         if (err) {
4504                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4505                        SCSI_TAPE_MAJOR);
4506                 goto err_class;
4507         }
4508
4509         err = scsi_register_driver(&st_template.gendrv);
4510         if (err)
4511                 goto err_chrdev;
4512
4513         return 0;
4514
4515 err_chrdev:
4516         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4517                                  ST_MAX_TAPE_ENTRIES);
4518 err_class:
4519         class_unregister(&st_sysfs_class);
4520         return err;
4521 }
4522
4523 static void __exit exit_st(void)
4524 {
4525         scsi_unregister_driver(&st_template.gendrv);
4526         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4527                                  ST_MAX_TAPE_ENTRIES);
4528         class_unregister(&st_sysfs_class);
4529         idr_destroy(&st_index_idr);
4530         printk(KERN_INFO "st: Unloaded.\n");
4531 }
4532
4533 module_init(init_st);
4534 module_exit(exit_st);
4535
4536
4537 /* The sysfs driver interface. Read-only at the moment */
4538 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4539 {
4540         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4541 }
4542 static DRIVER_ATTR_RO(try_direct_io);
4543
4544 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4545 {
4546         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4547 }
4548 static DRIVER_ATTR_RO(fixed_buffer_size);
4549
4550 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4551 {
4552         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4553 }
4554 static DRIVER_ATTR_RO(max_sg_segs);
4555
4556 static ssize_t version_show(struct device_driver *ddd, char *buf)
4557 {
4558         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4559 }
4560 static DRIVER_ATTR_RO(version);
4561
4562 #if DEBUG
4563 static ssize_t debug_flag_store(struct device_driver *ddp,
4564         const char *buf, size_t count)
4565 {
4566 /* We only care what the first byte of the data is the rest is unused.
4567  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4568  * other values have -EINVAL returned if they are passed in.
4569  */
4570         if (count > 0) {
4571                 if (buf[0] == '0') {
4572                         debugging = NO_DEBUG;
4573                         return count;
4574                 } else if (buf[0] == '1') {
4575                         debugging = 1;
4576                         return count;
4577                 }
4578         }
4579         return -EINVAL;
4580 }
4581
4582 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4583 {
4584         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4585 }
4586 static DRIVER_ATTR_RW(debug_flag);
4587 #endif
4588
4589 static struct attribute *st_drv_attrs[] = {
4590         &driver_attr_try_direct_io.attr,
4591         &driver_attr_fixed_buffer_size.attr,
4592         &driver_attr_max_sg_segs.attr,
4593         &driver_attr_version.attr,
4594 #if DEBUG
4595         &driver_attr_debug_flag.attr,
4596 #endif
4597         NULL,
4598 };
4599 ATTRIBUTE_GROUPS(st_drv);
4600
4601 /* The sysfs simple class interface */
4602 static ssize_t
4603 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4604 {
4605         struct st_modedef *STm = dev_get_drvdata(dev);
4606         ssize_t l = 0;
4607
4608         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4609         return l;
4610 }
4611 static DEVICE_ATTR_RO(defined);
4612
4613 static ssize_t
4614 default_blksize_show(struct device *dev, struct device_attribute *attr,
4615                      char *buf)
4616 {
4617         struct st_modedef *STm = dev_get_drvdata(dev);
4618         ssize_t l = 0;
4619
4620         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4621         return l;
4622 }
4623 static DEVICE_ATTR_RO(default_blksize);
4624
4625 static ssize_t
4626 default_density_show(struct device *dev, struct device_attribute *attr,
4627                      char *buf)
4628 {
4629         struct st_modedef *STm = dev_get_drvdata(dev);
4630         ssize_t l = 0;
4631         char *fmt;
4632
4633         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4634         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4635         return l;
4636 }
4637 static DEVICE_ATTR_RO(default_density);
4638
4639 static ssize_t
4640 default_compression_show(struct device *dev, struct device_attribute *attr,
4641                          char *buf)
4642 {
4643         struct st_modedef *STm = dev_get_drvdata(dev);
4644         ssize_t l = 0;
4645
4646         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4647         return l;
4648 }
4649 static DEVICE_ATTR_RO(default_compression);
4650
4651 static ssize_t
4652 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4653 {
4654         struct st_modedef *STm = dev_get_drvdata(dev);
4655         struct scsi_tape *STp = STm->tape;
4656         int options;
4657         ssize_t l = 0;
4658
4659         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4660         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4661         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4662         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4663         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4664         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4665         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4666         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4667         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4668         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4669         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4670         options |= STm->sysv ? MT_ST_SYSV : 0;
4671         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4672         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4673         options |= STp->sili ? MT_ST_SILI : 0;
4674
4675         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4676         return l;
4677 }
4678 static DEVICE_ATTR_RO(options);
4679
4680 /* Support for tape stats */
4681
4682 /**
4683  * read_cnt_show - return read count - count of reads made from tape drive
4684  * @dev: struct device
4685  * @attr: attribute structure
4686  * @buf: buffer to return formatted data in
4687  */
4688 static ssize_t read_cnt_show(struct device *dev,
4689         struct device_attribute *attr, char *buf)
4690 {
4691         struct st_modedef *STm = dev_get_drvdata(dev);
4692
4693         return sprintf(buf, "%lld",
4694                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4695 }
4696 static DEVICE_ATTR_RO(read_cnt);
4697
4698 /**
4699  * read_byte_cnt_show - return read byte count - tape drives
4700  * may use blocks less than 512 bytes this gives the raw byte count of
4701  * of data read from the tape drive.
4702  * @dev: struct device
4703  * @attr: attribute structure
4704  * @buf: buffer to return formatted data in
4705  */
4706 static ssize_t read_byte_cnt_show(struct device *dev,
4707         struct device_attribute *attr, char *buf)
4708 {
4709         struct st_modedef *STm = dev_get_drvdata(dev);
4710
4711         return sprintf(buf, "%lld",
4712                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4713 }
4714 static DEVICE_ATTR_RO(read_byte_cnt);
4715
4716 /**
4717  * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4718  * @dev: struct device
4719  * @attr: attribute structure
4720  * @buf: buffer to return formatted data in
4721  */
4722 static ssize_t read_ns_show(struct device *dev,
4723         struct device_attribute *attr, char *buf)
4724 {
4725         struct st_modedef *STm = dev_get_drvdata(dev);
4726
4727         return sprintf(buf, "%lld",
4728                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4729 }
4730 static DEVICE_ATTR_RO(read_ns);
4731
4732 /**
4733  * write_cnt_show - write count - number of user calls
4734  * to write(2) that have written data to tape.
4735  * @dev: struct device
4736  * @attr: attribute structure
4737  * @buf: buffer to return formatted data in
4738  */
4739 static ssize_t write_cnt_show(struct device *dev,
4740         struct device_attribute *attr, char *buf)
4741 {
4742         struct st_modedef *STm = dev_get_drvdata(dev);
4743
4744         return sprintf(buf, "%lld",
4745                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4746 }
4747 static DEVICE_ATTR_RO(write_cnt);
4748
4749 /**
4750  * write_byte_cnt_show - write byte count - raw count of
4751  * bytes written to tape.
4752  * @dev: struct device
4753  * @attr: attribute structure
4754  * @buf: buffer to return formatted data in
4755  */
4756 static ssize_t write_byte_cnt_show(struct device *dev,
4757         struct device_attribute *attr, char *buf)
4758 {
4759         struct st_modedef *STm = dev_get_drvdata(dev);
4760
4761         return sprintf(buf, "%lld",
4762                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4763 }
4764 static DEVICE_ATTR_RO(write_byte_cnt);
4765
4766 /**
4767  * write_ns_show - write ns - number of nanoseconds waiting on write
4768  * requests to complete.
4769  * @dev: struct device
4770  * @attr: attribute structure
4771  * @buf: buffer to return formatted data in
4772  */
4773 static ssize_t write_ns_show(struct device *dev,
4774         struct device_attribute *attr, char *buf)
4775 {
4776         struct st_modedef *STm = dev_get_drvdata(dev);
4777
4778         return sprintf(buf, "%lld",
4779                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4780 }
4781 static DEVICE_ATTR_RO(write_ns);
4782
4783 /**
4784  * in_flight_show - number of I/Os currently in flight -
4785  * in most cases this will be either 0 or 1. It may be higher if someone
4786  * has also issued other SCSI commands such as via an ioctl.
4787  * @dev: struct device
4788  * @attr: attribute structure
4789  * @buf: buffer to return formatted data in
4790  */
4791 static ssize_t in_flight_show(struct device *dev,
4792         struct device_attribute *attr, char *buf)
4793 {
4794         struct st_modedef *STm = dev_get_drvdata(dev);
4795
4796         return sprintf(buf, "%lld",
4797                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4798 }
4799 static DEVICE_ATTR_RO(in_flight);
4800
4801 /**
4802  * io_ns_show - io wait ns - this is the number of ns spent
4803  * waiting on all I/O to complete. This includes tape movement commands
4804  * such as rewinding, seeking to end of file or tape, it also includes
4805  * read and write. To determine the time spent on tape movement
4806  * subtract the read and write ns from this value.
4807  * @dev: struct device
4808  * @attr: attribute structure
4809  * @buf: buffer to return formatted data in
4810  */
4811 static ssize_t io_ns_show(struct device *dev,
4812         struct device_attribute *attr, char *buf)
4813 {
4814         struct st_modedef *STm = dev_get_drvdata(dev);
4815
4816         return sprintf(buf, "%lld",
4817                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4818 }
4819 static DEVICE_ATTR_RO(io_ns);
4820
4821 /**
4822  * other_cnt_show - other io count - this is the number of
4823  * I/O requests other than read and write requests.
4824  * Typically these are tape movement requests but will include driver
4825  * tape movement. This includes only requests issued by the st driver.
4826  * @dev: struct device
4827  * @attr: attribute structure
4828  * @buf: buffer to return formatted data in
4829  */
4830 static ssize_t other_cnt_show(struct device *dev,
4831         struct device_attribute *attr, char *buf)
4832 {
4833         struct st_modedef *STm = dev_get_drvdata(dev);
4834
4835         return sprintf(buf, "%lld",
4836                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4837 }
4838 static DEVICE_ATTR_RO(other_cnt);
4839
4840 /**
4841  * resid_cnt_show - A count of the number of times we get a residual
4842  * count - this should indicate someone issuing reads larger than the
4843  * block size on tape.
4844  * @dev: struct device
4845  * @attr: attribute structure
4846  * @buf: buffer to return formatted data in
4847  */
4848 static ssize_t resid_cnt_show(struct device *dev,
4849         struct device_attribute *attr, char *buf)
4850 {
4851         struct st_modedef *STm = dev_get_drvdata(dev);
4852
4853         return sprintf(buf, "%lld",
4854                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4855 }
4856 static DEVICE_ATTR_RO(resid_cnt);
4857
4858 static struct attribute *st_dev_attrs[] = {
4859         &dev_attr_defined.attr,
4860         &dev_attr_default_blksize.attr,
4861         &dev_attr_default_density.attr,
4862         &dev_attr_default_compression.attr,
4863         &dev_attr_options.attr,
4864         NULL,
4865 };
4866
4867 static struct attribute *st_stats_attrs[] = {
4868         &dev_attr_read_cnt.attr,
4869         &dev_attr_read_byte_cnt.attr,
4870         &dev_attr_read_ns.attr,
4871         &dev_attr_write_cnt.attr,
4872         &dev_attr_write_byte_cnt.attr,
4873         &dev_attr_write_ns.attr,
4874         &dev_attr_in_flight.attr,
4875         &dev_attr_io_ns.attr,
4876         &dev_attr_other_cnt.attr,
4877         &dev_attr_resid_cnt.attr,
4878         NULL,
4879 };
4880
4881 static struct attribute_group stats_group = {
4882         .name = "stats",
4883         .attrs = st_stats_attrs,
4884 };
4885
4886 static struct attribute_group st_group = {
4887         .attrs = st_dev_attrs,
4888 };
4889
4890 static const struct attribute_group *st_dev_groups[] = {
4891         &st_group,
4892         &stats_group,
4893         NULL,
4894 };
4895
4896 /* The following functions may be useful for a larger audience. */
4897 static int sgl_map_user_pages(struct st_buffer *STbp,
4898                               const unsigned int max_pages, unsigned long uaddr,
4899                               size_t count, int rw)
4900 {
4901         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4902         unsigned long start = uaddr >> PAGE_SHIFT;
4903         const int nr_pages = end - start;
4904         int res, i, j;
4905         struct page **pages;
4906         struct rq_map_data *mdata = &STbp->map_data;
4907
4908         /* User attempted Overflow! */
4909         if ((uaddr + count) < uaddr)
4910                 return -EINVAL;
4911
4912         /* Too big */
4913         if (nr_pages > max_pages)
4914                 return -ENOMEM;
4915
4916         /* Hmm? */
4917         if (count == 0)
4918                 return 0;
4919
4920         pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
4921         if (pages == NULL)
4922                 return -ENOMEM;
4923
4924         /* Try to fault in all of the necessary pages */
4925         /* rw==READ means read from drive, write into memory area */
4926         res = get_user_pages_fast(uaddr, nr_pages, rw == READ ? FOLL_WRITE : 0,
4927                                   pages);
4928
4929         /* Errors and no page mapped should return here */
4930         if (res < nr_pages)
4931                 goto out_unmap;
4932
4933         for (i=0; i < nr_pages; i++) {
4934                 /* FIXME: flush superflous for rw==READ,
4935                  * probably wrong function for rw==WRITE
4936                  */
4937                 flush_dcache_page(pages[i]);
4938         }
4939
4940         mdata->offset = uaddr & ~PAGE_MASK;
4941         STbp->mapped_pages = pages;
4942
4943         return nr_pages;
4944  out_unmap:
4945         if (res > 0) {
4946                 for (j=0; j < res; j++)
4947                         put_page(pages[j]);
4948                 res = 0;
4949         }
4950         kfree(pages);
4951         return res;
4952 }
4953
4954
4955 /* And unmap them... */
4956 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4957                                 const unsigned int nr_pages, int dirtied)
4958 {
4959         int i;
4960
4961         for (i=0; i < nr_pages; i++) {
4962                 struct page *page = STbp->mapped_pages[i];
4963
4964                 if (dirtied)
4965                         SetPageDirty(page);
4966                 /* FIXME: cache flush missing for rw==READ
4967                  * FIXME: call the correct reference counting function
4968                  */
4969                 put_page(page);
4970         }
4971         kfree(STbp->mapped_pages);
4972         STbp->mapped_pages = NULL;
4973
4974         return 0;
4975 }