drivers/scsi/hosts.c

   1 /*
   2  *  hosts.c Copyright (C) 1992 Drew Eckhardt
   3  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
   4  *          Copyright (C) 2002-2003 Christoph Hellwig
   5  *
   6  *  mid to lowlevel SCSI driver interface
   7  *      Initial versions: Drew Eckhardt
   8  *      Subsequent revisions: Eric Youngdale
   9  *
  10  *  <drew@colorado.edu>
  11  *
  12  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
  13  *  Added QLOGIC QLA1280 SCSI controller kernel host support.
  14  *     August 4, 1999 Fred Lewis, Intel DuPont
  15  *
  16  *  Updated to reflect the new initialization scheme for the higher
  17  *  level of scsi drivers (sd/sr/st)
  18  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
  19  *
  20  *  Restructured scsi_host lists and associated functions.
  21  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/kernel.h>
  27 #include <linux/slab.h>
  28 #include <linux/kthread.h>
  29 #include <linux/string.h>
  30 #include <linux/mm.h>
  31 #include <linux/init.h>
  32 #include <linux/completion.h>
  33 #include <linux/transport_class.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/pm_runtime.h>
  36 #include <linux/idr.h>
  37 #include <scsi/scsi_device.h>
  38 #include <scsi/scsi_host.h>
  39 #include <scsi/scsi_transport.h>
  40
  41 #include "scsi_priv.h"
  42 #include "scsi_logging.h"
  43
  44
  45 static DEFINE_IDA(host_index_ida);
  46
  47
  48 static void scsi_host_cls_release(struct device *dev)
  49 {
  50         put_device(&class_to_shost(dev)->shost_gendev);
  51 }
  52
  53 static struct class shost_class = {
  54         .name           = "scsi_host",
  55         .dev_release    = scsi_host_cls_release,
  56 };
  57
  58 /**
  59  *      scsi_host_set_state - Take the given host through the host state model.
  60  *      @shost: scsi host to change the state of.
  61  *      @state: state to change to.
  62  *
  63  *      Returns zero if unsuccessful or an error if the requested
  64  *      transition is illegal.
  65  **/
  66 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  67 {
  68         enum scsi_host_state oldstate = shost->shost_state;
  69
  70         if (state == oldstate)
  71                 return 0;
  72
  73         switch (state) {
  74         case SHOST_CREATED:
  75                 /* There are no legal states that come back to
  76                  * created.  This is the manually initialised start
  77                  * state */
  78                 goto illegal;
  79
  80         case SHOST_RUNNING:
  81                 switch (oldstate) {
  82                 case SHOST_CREATED:
  83                 case SHOST_RECOVERY:
  84                         break;
  85                 default:
  86                         goto illegal;
  87                 }
  88                 break;
  89
  90         case SHOST_RECOVERY:
  91                 switch (oldstate) {
  92                 case SHOST_RUNNING:
  93                         break;
  94                 default:
  95                         goto illegal;
  96                 }
  97                 break;
  98
  99         case SHOST_CANCEL:
 100                 switch (oldstate) {
 101                 case SHOST_CREATED:
 102                 case SHOST_RUNNING:
 103                 case SHOST_CANCEL_RECOVERY:
 104                         break;
 105                 default:
 106                         goto illegal;
 107                 }
 108                 break;
 109
 110         case SHOST_DEL:
 111                 switch (oldstate) {
 112                 case SHOST_CANCEL:
 113                 case SHOST_DEL_RECOVERY:
 114                         break;
 115                 default:
 116                         goto illegal;
 117                 }
 118                 break;
 119
 120         case SHOST_CANCEL_RECOVERY:
 121                 switch (oldstate) {
 122                 case SHOST_CANCEL:
 123                 case SHOST_RECOVERY:
 124                         break;
 125                 default:
 126                         goto illegal;
 127                 }
 128                 break;
 129
 130         case SHOST_DEL_RECOVERY:
 131                 switch (oldstate) {
 132                 case SHOST_CANCEL_RECOVERY:
 133                         break;
 134                 default:
 135                         goto illegal;
 136                 }
 137                 break;
 138         }
 139         shost->shost_state = state;
 140         return 0;
 141
 142  illegal:
 143         SCSI_LOG_ERROR_RECOVERY(1,
 144                                 shost_printk(KERN_ERR, shost,
 145                                              "Illegal host state transition"
 146                                              "%s->%s\n",
 147                                              scsi_host_state_name(oldstate),
 148                                              scsi_host_state_name(state)));
 149         return -EINVAL;
 150 }
 151 EXPORT_SYMBOL(scsi_host_set_state);
 152
 153 /**
 154  * scsi_remove_host - remove a scsi host
 155  * @shost:      a pointer to a scsi host to remove
 156  **/
 157 void scsi_remove_host(struct Scsi_Host *shost)
 158 {
 159         unsigned long flags;
 160
 161         mutex_lock(&shost->scan_mutex);
 162         spin_lock_irqsave(shost->host_lock, flags);
 163         if (scsi_host_set_state(shost, SHOST_CANCEL))
 164                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 165                         spin_unlock_irqrestore(shost->host_lock, flags);
 166                         mutex_unlock(&shost->scan_mutex);
 167                         return;
 168                 }
 169         spin_unlock_irqrestore(shost->host_lock, flags);
 170
 171         scsi_autopm_get_host(shost);
 172         flush_workqueue(shost->tmf_work_q);
 173         scsi_forget_host(shost);
 174         mutex_unlock(&shost->scan_mutex);
 175         scsi_proc_host_rm(shost);
 176
 177         spin_lock_irqsave(shost->host_lock, flags);
 178         if (scsi_host_set_state(shost, SHOST_DEL))
 179                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 180         spin_unlock_irqrestore(shost->host_lock, flags);
 181
 182         transport_unregister_device(&shost->shost_gendev);
 183         device_unregister(&shost->shost_dev);
 184         device_del(&shost->shost_gendev);
 185 }
 186 EXPORT_SYMBOL(scsi_remove_host);
 187
 188 /**
 189  * scsi_add_host_with_dma - add a scsi host with dma device
 190  * @shost:      scsi host pointer to add
 191  * @dev:        a struct device of type scsi class
 192  * @dma_dev:    dma device for the host
 193  *
 194  * Note: You rarely need to worry about this unless you're in a
 195  * virtualised host environments, so use the simpler scsi_add_host()
 196  * function instead.
 197  *
 198  * Return value:
 199  *      0 on success / != 0 for error
 200  **/
 201 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 202                            struct device *dma_dev)
 203 {
 204         struct scsi_host_template *sht = shost->hostt;
 205         int error = -EINVAL;
 206
 207         shost_printk(KERN_INFO, shost, "%s\n",
 208                         sht->info ? sht->info(shost) : sht->name);
 209
 210         if (!shost->can_queue) {
 211                 shost_printk(KERN_ERR, shost,
 212                              "can_queue = 0 no longer supported\n");
 213                 goto fail;
 214         }
 215
 216         error = scsi_init_sense_cache(shost);
 217         if (error)
 218                 goto fail;
 219
 220         if (shost_use_blk_mq(shost)) {
 221                 error = scsi_mq_setup_tags(shost);
 222                 if (error)
 223                         goto fail;
 224         } else {
 225                 shost->bqt = blk_init_tags(shost->can_queue,
 226                                 shost->hostt->tag_alloc_policy);
 227                 if (!shost->bqt) {
 228                         error = -ENOMEM;
 229                         goto fail;
 230                 }
 231         }
 232
 233         if (!shost->shost_gendev.parent)
 234                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 235         if (!dma_dev)
 236                 dma_dev = shost->shost_gendev.parent;
 237
 238         shost->dma_dev = dma_dev;
 239
 240         /*
 241          * Increase usage count temporarily here so that calling
 242          * scsi_autopm_put_host() will trigger runtime idle if there is
 243          * nothing else preventing suspending the device.
 244          */
 245         pm_runtime_get_noresume(&shost->shost_gendev);
 246         pm_runtime_set_active(&shost->shost_gendev);
 247         pm_runtime_enable(&shost->shost_gendev);
 248         device_enable_async_suspend(&shost->shost_gendev);
 249
 250         error = device_add(&shost->shost_gendev);
 251         if (error)
 252                 goto out_disable_runtime_pm;
 253
 254         scsi_host_set_state(shost, SHOST_RUNNING);
 255         get_device(shost->shost_gendev.parent);
 256
 257         device_enable_async_suspend(&shost->shost_dev);
 258
 259         error = device_add(&shost->shost_dev);
 260         if (error)
 261                 goto out_del_gendev;
 262
 263         get_device(&shost->shost_gendev);
 264
 265         if (shost->transportt->host_size) {
 266                 shost->shost_data = kzalloc(shost->transportt->host_size,
 267                                          GFP_KERNEL);
 268                 if (shost->shost_data == NULL) {
 269                         error = -ENOMEM;
 270                         goto out_del_dev;
 271                 }
 272         }
 273
 274         if (shost->transportt->create_work_queue) {
 275                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 276                          "scsi_wq_%d", shost->host_no);
 277                 shost->work_q = create_singlethread_workqueue(
 278                                         shost->work_q_name);
 279                 if (!shost->work_q) {
 280                         error = -EINVAL;
 281                         goto out_free_shost_data;
 282                 }
 283         }
 284
 285         error = scsi_sysfs_add_host(shost);
 286         if (error)
 287                 goto out_destroy_host;
 288
 289         scsi_proc_host_add(shost);
 290         scsi_autopm_put_host(shost);
 291         return error;
 292
 293  out_destroy_host:
 294         if (shost->work_q)
 295                 destroy_workqueue(shost->work_q);
 296  out_free_shost_data:
 297         kfree(shost->shost_data);
 298  out_del_dev:
 299         device_del(&shost->shost_dev);
 300  out_del_gendev:
 301         device_del(&shost->shost_gendev);
 302  out_disable_runtime_pm:
 303         device_disable_async_suspend(&shost->shost_gendev);
 304         pm_runtime_disable(&shost->shost_gendev);
 305         pm_runtime_set_suspended(&shost->shost_gendev);
 306         pm_runtime_put_noidle(&shost->shost_gendev);
 307         if (shost_use_blk_mq(shost))
 308                 scsi_mq_destroy_tags(shost);
 309  fail:
 310         return error;
 311 }
 312 EXPORT_SYMBOL(scsi_add_host_with_dma);
 313
 314 static void scsi_host_dev_release(struct device *dev)
 315 {
 316         struct Scsi_Host *shost = dev_to_shost(dev);
 317         struct device *parent = dev->parent;
 318
 319         scsi_proc_hostdir_rm(shost->hostt);
 320
 321         /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
 322         rcu_barrier();
 323
 324         if (shost->tmf_work_q)
 325                 destroy_workqueue(shost->tmf_work_q);
 326         if (shost->ehandler)
 327                 kthread_stop(shost->ehandler);
 328         if (shost->work_q)
 329                 destroy_workqueue(shost->work_q);
 330
 331         if (shost->shost_state == SHOST_CREATED) {
 332                 /*
 333                  * Free the shost_dev device name here if scsi_host_alloc()
 334                  * and scsi_host_put() have been called but neither
 335                  * scsi_host_add() nor scsi_host_remove() has been called.
 336                  * This avoids that the memory allocated for the shost_dev
 337                  * name is leaked.
 338                  */
 339                 kfree(dev_name(&shost->shost_dev));
 340         }
 341
 342         if (shost_use_blk_mq(shost)) {
 343                 if (shost->tag_set.tags)
 344                         scsi_mq_destroy_tags(shost);
 345         } else {
 346                 if (shost->bqt)
 347                         blk_free_tags(shost->bqt);
 348         }
 349
 350         kfree(shost->shost_data);
 351
 352         ida_simple_remove(&host_index_ida, shost->host_no);
 353
 354         if (parent)
 355                 put_device(parent);
 356         kfree(shost);
 357 }
 358
 359 static int shost_eh_deadline = -1;
 360
 361 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
 362 MODULE_PARM_DESC(eh_deadline,
 363                  "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
 364
 365 static struct device_type scsi_host_type = {
 366         .name =         "scsi_host",
 367         .release =      scsi_host_dev_release,
 368 };
 369
 370 /**
 371  * scsi_host_alloc - register a scsi host adapter instance.
 372  * @sht:        pointer to scsi host template
 373  * @privsize:   extra bytes to allocate for driver
 374  *
 375  * Note:
 376  *      Allocate a new Scsi_Host and perform basic initialization.
 377  *      The host is not published to the scsi midlayer until scsi_add_host
 378  *      is called.
 379  *
 380  * Return value:
 381  *      Pointer to a new Scsi_Host
 382  **/
 383 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 384 {
 385         struct Scsi_Host *shost;
 386         gfp_t gfp_mask = GFP_KERNEL;
 387         int index;
 388
 389         if (sht->unchecked_isa_dma && privsize)
 390                 gfp_mask |= __GFP_DMA;
 391
 392         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 393         if (!shost)
 394                 return NULL;
 395
 396         shost->host_lock = &shost->default_lock;
 397         spin_lock_init(shost->host_lock);
 398         shost->shost_state = SHOST_CREATED;
 399         INIT_LIST_HEAD(&shost->__devices);
 400         INIT_LIST_HEAD(&shost->__targets);
 401         INIT_LIST_HEAD(&shost->eh_cmd_q);
 402         INIT_LIST_HEAD(&shost->starved_list);
 403         init_waitqueue_head(&shost->host_wait);
 404         mutex_init(&shost->scan_mutex);
 405
 406         index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
 407         if (index < 0)
 408                 goto fail_kfree;
 409         shost->host_no = index;
 410
 411         shost->dma_channel = 0xff;
 412
 413         /* These three are default values which can be overridden */
 414         shost->max_channel = 0;
 415         shost->max_id = 8;
 416         shost->max_lun = 8;
 417
 418         /* Give each shost a default transportt */
 419         shost->transportt = &blank_transport_template;
 420
 421         /*
 422          * All drivers right now should be able to handle 12 byte
 423          * commands.  Every so often there are requests for 16 byte
 424          * commands, but individual low-level drivers need to certify that
 425          * they actually do something sensible with such commands.
 426          */
 427         shost->max_cmd_len = 12;
 428         shost->hostt = sht;
 429         shost->this_id = sht->this_id;
 430         shost->can_queue = sht->can_queue;
 431         shost->sg_tablesize = sht->sg_tablesize;
 432         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 433         shost->cmd_per_lun = sht->cmd_per_lun;
 434         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 435         shost->use_clustering = sht->use_clustering;
 436         shost->no_write_same = sht->no_write_same;
 437
 438         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 439                 shost->eh_deadline = -1;
 440         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 441                 shost_printk(KERN_WARNING, shost,
 442                              "eh_deadline %u too large, setting to %u\n",
 443                              shost_eh_deadline, INT_MAX / HZ);
 444                 shost->eh_deadline = INT_MAX;
 445         } else
 446                 shost->eh_deadline = shost_eh_deadline * HZ;
 447
 448         if (sht->supported_mode == MODE_UNKNOWN)
 449                 /* means we didn't set it ... default to INITIATOR */
 450                 shost->active_mode = MODE_INITIATOR;
 451         else
 452                 shost->active_mode = sht->supported_mode;
 453
 454         if (sht->max_host_blocked)
 455                 shost->max_host_blocked = sht->max_host_blocked;
 456         else
 457                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 458
 459         /*
 460          * If the driver imposes no hard sector transfer limit, start at
 461          * machine infinity initially.
 462          */
 463         if (sht->max_sectors)
 464                 shost->max_sectors = sht->max_sectors;
 465         else
 466                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 467
 468         /*
 469          * assume a 4GB boundary, if not set
 470          */
 471         if (sht->dma_boundary)
 472                 shost->dma_boundary = sht->dma_boundary;
 473         else
 474                 shost->dma_boundary = 0xffffffff;
 475
 476         shost->use_blk_mq = scsi_use_blk_mq;
 477
 478         device_initialize(&shost->shost_gendev);
 479         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 480         shost->shost_gendev.bus = &scsi_bus_type;
 481         shost->shost_gendev.type = &scsi_host_type;
 482
 483         device_initialize(&shost->shost_dev);
 484         shost->shost_dev.parent = &shost->shost_gendev;
 485         shost->shost_dev.class = &shost_class;
 486         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 487         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 488
 489         shost->ehandler = kthread_run(scsi_error_handler, shost,
 490                         "scsi_eh_%d", shost->host_no);
 491         if (IS_ERR(shost->ehandler)) {
 492                 shost_printk(KERN_WARNING, shost,
 493                         "error handler thread failed to spawn, error = %ld\n",
 494                         PTR_ERR(shost->ehandler));
 495                 goto fail_index_remove;
 496         }
 497
 498         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 499                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 500                                            1, shost->host_no);
 501         if (!shost->tmf_work_q) {
 502                 shost_printk(KERN_WARNING, shost,
 503                              "failed to create tmf workq\n");
 504                 goto fail_kthread;
 505         }
 506         scsi_proc_hostdir_add(shost->hostt);
 507         return shost;
 508
 509  fail_kthread:
 510         kthread_stop(shost->ehandler);
 511  fail_index_remove:
 512         ida_simple_remove(&host_index_ida, shost->host_no);
 513  fail_kfree:
 514         kfree(shost);
 515         return NULL;
 516 }
 517 EXPORT_SYMBOL(scsi_host_alloc);
 518
 519 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 520 {
 521         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 522
 523         if (!sht->detect) {
 524                 printk(KERN_WARNING "scsi_register() called on new-style "
 525                                     "template for driver %s\n", sht->name);
 526                 dump_stack();
 527         }
 528
 529         if (shost)
 530                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 531         return shost;
 532 }
 533 EXPORT_SYMBOL(scsi_register);
 534
 535 void scsi_unregister(struct Scsi_Host *shost)
 536 {
 537         list_del(&shost->sht_legacy_list);
 538         scsi_host_put(shost);
 539 }
 540 EXPORT_SYMBOL(scsi_unregister);
 541
 542 static int __scsi_host_match(struct device *dev, const void *data)
 543 {
 544         struct Scsi_Host *p;
 545         const unsigned short *hostnum = data;
 546
 547         p = class_to_shost(dev);
 548         return p->host_no == *hostnum;
 549 }
 550
 551 /**
 552  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 553  * @hostnum:    host number to locate
 554  *
 555  * Return value:
 556  *      A pointer to located Scsi_Host or NULL.
 557  *
 558  *      The caller must do a scsi_host_put() to drop the reference
 559  *      that scsi_host_get() took. The put_device() below dropped
 560  *      the reference from class_find_device().
 561  **/
 562 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 563 {
 564         struct device *cdev;
 565         struct Scsi_Host *shost = NULL;
 566
 567         cdev = class_find_device(&shost_class, NULL, &hostnum,
 568                                  __scsi_host_match);
 569         if (cdev) {
 570                 shost = scsi_host_get(class_to_shost(cdev));
 571                 put_device(cdev);
 572         }
 573         return shost;
 574 }
 575 EXPORT_SYMBOL(scsi_host_lookup);
 576
 577 /**
 578  * scsi_host_get - inc a Scsi_Host ref count
 579  * @shost:      Pointer to Scsi_Host to inc.
 580  **/
 581 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 582 {
 583         if ((shost->shost_state == SHOST_DEL) ||
 584                 !get_device(&shost->shost_gendev))
 585                 return NULL;
 586         return shost;
 587 }
 588 EXPORT_SYMBOL(scsi_host_get);
 589
 590 /**
 591  * scsi_host_put - dec a Scsi_Host ref count
 592  * @shost:      Pointer to Scsi_Host to dec.
 593  **/
 594 void scsi_host_put(struct Scsi_Host *shost)
 595 {
 596         put_device(&shost->shost_gendev);
 597 }
 598 EXPORT_SYMBOL(scsi_host_put);
 599
 600 int scsi_init_hosts(void)
 601 {
 602         return class_register(&shost_class);
 603 }
 604
 605 void scsi_exit_hosts(void)
 606 {
 607         class_unregister(&shost_class);
 608         ida_destroy(&host_index_ida);
 609 }
 610
 611 int scsi_is_host_device(const struct device *dev)
 612 {
 613         return dev->type == &scsi_host_type;
 614 }
 615 EXPORT_SYMBOL(scsi_is_host_device);
 616
 617 /**
 618  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 619  * @shost:      Pointer to Scsi_Host.
 620  * @work:       Work to queue for execution.
 621  *
 622  * Return value:
 623  *      1 - work queued for execution
 624  *      0 - work is already queued
 625  *      -EINVAL - work queue doesn't exist
 626  **/
 627 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 628 {
 629         if (unlikely(!shost->work_q)) {
 630                 shost_printk(KERN_ERR, shost,
 631                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 632                         "when no workqueue created.\n", shost->hostt->name);
 633                 dump_stack();
 634
 635                 return -EINVAL;
 636         }
 637
 638         return queue_work(shost->work_q, work);
 639 }
 640 EXPORT_SYMBOL_GPL(scsi_queue_work);
 641
 642 /**
 643  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 644  * @shost:      Pointer to Scsi_Host.
 645  **/
 646 void scsi_flush_work(struct Scsi_Host *shost)
 647 {
 648         if (!shost->work_q) {
 649                 shost_printk(KERN_ERR, shost,
 650                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 651                         "when no workqueue created.\n", shost->hostt->name);
 652                 dump_stack();
 653                 return;
 654         }
 655
 656         flush_workqueue(shost->work_q);
 657 }
 658 EXPORT_SYMBOL_GPL(scsi_flush_work);