drivers/target/target_core_user.c

   1 /*
   2  * Copyright (C) 2013 Shaohua Li <shli@kernel.org>
   3  * Copyright (C) 2014 Red Hat, Inc.
   4  * Copyright (C) 2015 Arrikto, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <linux/spinlock.h>
  21 #include <linux/module.h>
  22 #include <linux/idr.h>
  23 #include <linux/kernel.h>
  24 #include <linux/timer.h>
  25 #include <linux/parser.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/uio_driver.h>
  28 #include <linux/stringify.h>
  29 #include <linux/bitops.h>
  30 #include <linux/highmem.h>
  31 #include <net/genetlink.h>
  32 #include <scsi/scsi_common.h>
  33 #include <scsi/scsi_proto.h>
  34 #include <target/target_core_base.h>
  35 #include <target/target_core_fabric.h>
  36 #include <target/target_core_backend.h>
  37
  38 #include <linux/target_core_user.h>
  39
  40 /*
  41  * Define a shared-memory interface for LIO to pass SCSI commands and
  42  * data to userspace for processing. This is to allow backends that
  43  * are too complex for in-kernel support to be possible.
  44  *
  45  * It uses the UIO framework to do a lot of the device-creation and
  46  * introspection work for us.
  47  *
  48  * See the .h file for how the ring is laid out. Note that while the
  49  * command ring is defined, the particulars of the data area are
  50  * not. Offset values in the command entry point to other locations
  51  * internal to the mmap()ed area. There is separate space outside the
  52  * command ring for data buffers. This leaves maximum flexibility for
  53  * moving buffer allocations, or even page flipping or other
  54  * allocation techniques, without altering the command ring layout.
  55  *
  56  * SECURITY:
  57  * The user process must be assumed to be malicious. There's no way to
  58  * prevent it breaking the command ring protocol if it wants, but in
  59  * order to prevent other issues we must only ever read *data* from
  60  * the shared memory area, not offsets or sizes. This applies to
  61  * command ring entries as well as the mailbox. Extra code needed for
  62  * this may have a 'UAM' comment.
  63  */
  64
  65
  66 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
  67
  68 #define DATA_BLOCK_BITS 256
  69 #define DATA_BLOCK_SIZE 4096
  70
  71 #define CMDR_SIZE (16 * 4096)
  72 #define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
  73
  74 #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
  75
  76 static struct device *tcmu_root_device;
  77
  78 struct tcmu_hba {
  79         u32 host_id;
  80 };
  81
  82 #define TCMU_CONFIG_LEN 256
  83
  84 struct tcmu_dev {
  85         struct se_device se_dev;
  86
  87         char *name;
  88         struct se_hba *hba;
  89
  90 #define TCMU_DEV_BIT_OPEN 0
  91 #define TCMU_DEV_BIT_BROKEN 1
  92         unsigned long flags;
  93
  94         struct uio_info uio_info;
  95
  96         struct tcmu_mailbox *mb_addr;
  97         size_t dev_size;
  98         u32 cmdr_size;
  99         u32 cmdr_last_cleaned;
 100         /* Offset of data area from start of mb */
 101         /* Must add data_off and mb_addr to get the address */
 102         size_t data_off;
 103         size_t data_size;
 104
 105         DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
 106
 107         wait_queue_head_t wait_cmdr;
 108         /* TODO should this be a mutex? */
 109         spinlock_t cmdr_lock;
 110
 111         struct idr commands;
 112         spinlock_t commands_lock;
 113
 114         struct timer_list timeout;
 115         unsigned int cmd_time_out;
 116
 117         char dev_config[TCMU_CONFIG_LEN];
 118 };
 119
 120 #define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
 121
 122 #define CMDR_OFF sizeof(struct tcmu_mailbox)
 123
 124 struct tcmu_cmd {
 125         struct se_cmd *se_cmd;
 126         struct tcmu_dev *tcmu_dev;
 127
 128         uint16_t cmd_id;
 129
 130         /* Can't use se_cmd when cleaning up expired cmds, because if
 131            cmd has been completed then accessing se_cmd is off limits */
 132         DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
 133
 134         unsigned long deadline;
 135
 136 #define TCMU_CMD_BIT_EXPIRED 0
 137         unsigned long flags;
 138 };
 139
 140 static struct kmem_cache *tcmu_cmd_cache;
 141
 142 /* multicast group */
 143 enum tcmu_multicast_groups {
 144         TCMU_MCGRP_CONFIG,
 145 };
 146
 147 static const struct genl_multicast_group tcmu_mcgrps[] = {
 148         [TCMU_MCGRP_CONFIG] = { .name = "config", },
 149 };
 150
 151 /* Our generic netlink family */
 152 static struct genl_family tcmu_genl_family __ro_after_init = {
 153         .module = THIS_MODULE,
 154         .hdrsize = 0,
 155         .name = "TCM-USER",
 156         .version = 1,
 157         .maxattr = TCMU_ATTR_MAX,
 158         .mcgrps = tcmu_mcgrps,
 159         .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
 160         .netnsok = true,
 161 };
 162
 163 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
 164 {
 165         struct se_device *se_dev = se_cmd->se_dev;
 166         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 167         struct tcmu_cmd *tcmu_cmd;
 168         int cmd_id;
 169
 170         tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
 171         if (!tcmu_cmd)
 172                 return NULL;
 173
 174         tcmu_cmd->se_cmd = se_cmd;
 175         tcmu_cmd->tcmu_dev = udev;
 176         if (udev->cmd_time_out)
 177                 tcmu_cmd->deadline = jiffies +
 178                                         msecs_to_jiffies(udev->cmd_time_out);
 179
 180         idr_preload(GFP_KERNEL);
 181         spin_lock_irq(&udev->commands_lock);
 182         cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0,
 183                 USHRT_MAX, GFP_NOWAIT);
 184         spin_unlock_irq(&udev->commands_lock);
 185         idr_preload_end();
 186
 187         if (cmd_id < 0) {
 188                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 189                 return NULL;
 190         }
 191         tcmu_cmd->cmd_id = cmd_id;
 192
 193         return tcmu_cmd;
 194 }
 195
 196 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
 197 {
 198         unsigned long offset = offset_in_page(vaddr);
 199
 200         size = round_up(size+offset, PAGE_SIZE);
 201         vaddr -= offset;
 202
 203         while (size) {
 204                 flush_dcache_page(virt_to_page(vaddr));
 205                 size -= PAGE_SIZE;
 206         }
 207 }
 208
 209 /*
 210  * Some ring helper functions. We don't assume size is a power of 2 so
 211  * we can't use circ_buf.h.
 212  */
 213 static inline size_t spc_used(size_t head, size_t tail, size_t size)
 214 {
 215         int diff = head - tail;
 216
 217         if (diff >= 0)
 218                 return diff;
 219         else
 220                 return size + diff;
 221 }
 222
 223 static inline size_t spc_free(size_t head, size_t tail, size_t size)
 224 {
 225         /* Keep 1 byte unused or we can't tell full from empty */
 226         return (size - spc_used(head, tail, size) - 1);
 227 }
 228
 229 static inline size_t head_to_end(size_t head, size_t size)
 230 {
 231         return size - head;
 232 }
 233
 234 static inline void new_iov(struct iovec **iov, int *iov_cnt,
 235                            struct tcmu_dev *udev)
 236 {
 237         struct iovec *iovec;
 238
 239         if (*iov_cnt != 0)
 240                 (*iov)++;
 241         (*iov_cnt)++;
 242
 243         iovec = *iov;
 244         memset(iovec, 0, sizeof(struct iovec));
 245 }
 246
 247 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
 248
 249 /* offset is relative to mb_addr */
 250 static inline size_t get_block_offset(struct tcmu_dev *dev,
 251                 int block, int remaining)
 252 {
 253         return dev->data_off + block * DATA_BLOCK_SIZE +
 254                 DATA_BLOCK_SIZE - remaining;
 255 }
 256
 257 static inline size_t iov_tail(struct tcmu_dev *udev, struct iovec *iov)
 258 {
 259         return (size_t)iov->iov_base + iov->iov_len;
 260 }
 261
 262 static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
 263         struct scatterlist *data_sg, unsigned int data_nents,
 264         struct iovec **iov, int *iov_cnt, bool copy_data)
 265 {
 266         int i, block;
 267         int block_remaining = 0;
 268         void *from, *to;
 269         size_t copy_bytes, to_offset;
 270         struct scatterlist *sg;
 271
 272         for_each_sg(data_sg, sg, data_nents, i) {
 273                 int sg_remaining = sg->length;
 274                 from = kmap_atomic(sg_page(sg)) + sg->offset;
 275                 while (sg_remaining > 0) {
 276                         if (block_remaining == 0) {
 277                                 block = find_first_zero_bit(udev->data_bitmap,
 278                                                 DATA_BLOCK_BITS);
 279                                 block_remaining = DATA_BLOCK_SIZE;
 280                                 set_bit(block, udev->data_bitmap);
 281                         }
 282                         copy_bytes = min_t(size_t, sg_remaining,
 283                                         block_remaining);
 284                         to_offset = get_block_offset(udev, block,
 285                                         block_remaining);
 286                         to = (void *)udev->mb_addr + to_offset;
 287                         if (*iov_cnt != 0 &&
 288                             to_offset == iov_tail(udev, *iov)) {
 289                                 (*iov)->iov_len += copy_bytes;
 290                         } else {
 291                                 new_iov(iov, iov_cnt, udev);
 292                                 (*iov)->iov_base = (void __user *) to_offset;
 293                                 (*iov)->iov_len = copy_bytes;
 294                         }
 295                         if (copy_data) {
 296                                 memcpy(to, from + sg->length - sg_remaining,
 297                                         copy_bytes);
 298                                 tcmu_flush_dcache_range(to, copy_bytes);
 299                         }
 300                         sg_remaining -= copy_bytes;
 301                         block_remaining -= copy_bytes;
 302                 }
 303                 kunmap_atomic(from - sg->offset);
 304         }
 305 }
 306
 307 static void free_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd)
 308 {
 309         bitmap_xor(udev->data_bitmap, udev->data_bitmap, cmd->data_bitmap,
 310                    DATA_BLOCK_BITS);
 311 }
 312
 313 static void gather_data_area(struct tcmu_dev *udev, unsigned long *cmd_bitmap,
 314                 struct scatterlist *data_sg, unsigned int data_nents)
 315 {
 316         int i, block;
 317         int block_remaining = 0;
 318         void *from, *to;
 319         size_t copy_bytes, from_offset;
 320         struct scatterlist *sg;
 321
 322         for_each_sg(data_sg, sg, data_nents, i) {
 323                 int sg_remaining = sg->length;
 324                 to = kmap_atomic(sg_page(sg)) + sg->offset;
 325                 while (sg_remaining > 0) {
 326                         if (block_remaining == 0) {
 327                                 block = find_first_bit(cmd_bitmap,
 328                                                 DATA_BLOCK_BITS);
 329                                 block_remaining = DATA_BLOCK_SIZE;
 330                                 clear_bit(block, cmd_bitmap);
 331                         }
 332                         copy_bytes = min_t(size_t, sg_remaining,
 333                                         block_remaining);
 334                         from_offset = get_block_offset(udev, block,
 335                                         block_remaining);
 336                         from = (void *) udev->mb_addr + from_offset;
 337                         tcmu_flush_dcache_range(from, copy_bytes);
 338                         memcpy(to + sg->length - sg_remaining, from,
 339                                         copy_bytes);
 340
 341                         sg_remaining -= copy_bytes;
 342                         block_remaining -= copy_bytes;
 343                 }
 344                 kunmap_atomic(to - sg->offset);
 345         }
 346 }
 347
 348 static inline size_t spc_bitmap_free(unsigned long *bitmap)
 349 {
 350         return DATA_BLOCK_SIZE * (DATA_BLOCK_BITS -
 351                         bitmap_weight(bitmap, DATA_BLOCK_BITS));
 352 }
 353
 354 /*
 355  * We can't queue a command until we have space available on the cmd ring *and*
 356  * space available on the data area.
 357  *
 358  * Called with ring lock held.
 359  */
 360 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed)
 361 {
 362         struct tcmu_mailbox *mb = udev->mb_addr;
 363         size_t space, cmd_needed;
 364         u32 cmd_head;
 365
 366         tcmu_flush_dcache_range(mb, sizeof(*mb));
 367
 368         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 369
 370         /*
 371          * If cmd end-of-ring space is too small then we need space for a NOP plus
 372          * original cmd - cmds are internally contiguous.
 373          */
 374         if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
 375                 cmd_needed = cmd_size;
 376         else
 377                 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
 378
 379         space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
 380         if (space < cmd_needed) {
 381                 pr_debug("no cmd space: %u %u %u\n", cmd_head,
 382                        udev->cmdr_last_cleaned, udev->cmdr_size);
 383                 return false;
 384         }
 385
 386         space = spc_bitmap_free(udev->data_bitmap);
 387         if (space < data_needed) {
 388                 pr_debug("no data space: only %zu available, but ask for %zu\n",
 389                                 space, data_needed);
 390                 return false;
 391         }
 392
 393         return true;
 394 }
 395
 396 static sense_reason_t
 397 tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
 398 {
 399         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
 400         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 401         size_t base_command_size, command_size;
 402         struct tcmu_mailbox *mb;
 403         struct tcmu_cmd_entry *entry;
 404         struct iovec *iov;
 405         int iov_cnt;
 406         uint32_t cmd_head;
 407         uint64_t cdb_off;
 408         bool copy_to_data_area;
 409         size_t data_length;
 410         DECLARE_BITMAP(old_bitmap, DATA_BLOCK_BITS);
 411
 412         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
 413                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 414
 415         /*
 416          * Must be a certain minimum size for response sense info, but
 417          * also may be larger if the iov array is large.
 418          *
 419          * We prepare way too many iovs for potential uses here, because it's
 420          * expensive to tell how many regions are freed in the bitmap
 421         */
 422         base_command_size = max(offsetof(struct tcmu_cmd_entry,
 423                                 req.iov[se_cmd->t_bidi_data_nents +
 424                                         se_cmd->t_data_nents]),
 425                                 sizeof(struct tcmu_cmd_entry));
 426         command_size = base_command_size
 427                 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
 428
 429         WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
 430
 431         spin_lock_irq(&udev->cmdr_lock);
 432
 433         mb = udev->mb_addr;
 434         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 435         data_length = se_cmd->data_length;
 436         if (se_cmd->se_cmd_flags & SCF_BIDI) {
 437                 BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
 438                 data_length += se_cmd->t_bidi_data_sg->length;
 439         }
 440         if ((command_size > (udev->cmdr_size / 2)) ||
 441             data_length > udev->data_size) {
 442                 pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu "
 443                         "cmd ring/data area\n", command_size, data_length,
 444                         udev->cmdr_size, udev->data_size);
 445                 spin_unlock_irq(&udev->cmdr_lock);
 446                 return TCM_INVALID_CDB_FIELD;
 447         }
 448
 449         while (!is_ring_space_avail(udev, command_size, data_length)) {
 450                 int ret;
 451                 DEFINE_WAIT(__wait);
 452
 453                 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
 454
 455                 pr_debug("sleeping for ring space\n");
 456                 spin_unlock_irq(&udev->cmdr_lock);
 457                 if (udev->cmd_time_out)
 458                         ret = schedule_timeout(
 459                                         msecs_to_jiffies(udev->cmd_time_out));
 460                 else
 461                         ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
 462                 finish_wait(&udev->wait_cmdr, &__wait);
 463                 if (!ret) {
 464                         pr_warn("tcmu: command timed out\n");
 465                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 466                 }
 467
 468                 spin_lock_irq(&udev->cmdr_lock);
 469
 470                 /* We dropped cmdr_lock, cmd_head is stale */
 471                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 472         }
 473
 474         /* Insert a PAD if end-of-ring space is too small */
 475         if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
 476                 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
 477
 478                 entry = (void *) mb + CMDR_OFF + cmd_head;
 479                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 480                 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
 481                 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
 482                 entry->hdr.cmd_id = 0; /* not used for PAD */
 483                 entry->hdr.kflags = 0;
 484                 entry->hdr.uflags = 0;
 485
 486                 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
 487
 488                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 489                 WARN_ON(cmd_head != 0);
 490         }
 491
 492         entry = (void *) mb + CMDR_OFF + cmd_head;
 493         tcmu_flush_dcache_range(entry, sizeof(*entry));
 494         tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
 495         tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
 496         entry->hdr.cmd_id = tcmu_cmd->cmd_id;
 497         entry->hdr.kflags = 0;
 498         entry->hdr.uflags = 0;
 499
 500         bitmap_copy(old_bitmap, udev->data_bitmap, DATA_BLOCK_BITS);
 501
 502         /* Handle allocating space from the data area */
 503         iov = &entry->req.iov[0];
 504         iov_cnt = 0;
 505         copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE
 506                 || se_cmd->se_cmd_flags & SCF_BIDI);
 507         alloc_and_scatter_data_area(udev, se_cmd->t_data_sg,
 508                 se_cmd->t_data_nents, &iov, &iov_cnt, copy_to_data_area);
 509         entry->req.iov_cnt = iov_cnt;
 510         entry->req.iov_dif_cnt = 0;
 511
 512         /* Handle BIDI commands */
 513         iov_cnt = 0;
 514         alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg,
 515                 se_cmd->t_bidi_data_nents, &iov, &iov_cnt, false);
 516         entry->req.iov_bidi_cnt = iov_cnt;
 517
 518         /* cmd's data_bitmap is what changed in process */
 519         bitmap_xor(tcmu_cmd->data_bitmap, old_bitmap, udev->data_bitmap,
 520                         DATA_BLOCK_BITS);
 521
 522         /* All offsets relative to mb_addr, not start of entry! */
 523         cdb_off = CMDR_OFF + cmd_head + base_command_size;
 524         memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
 525         entry->req.cdb_off = cdb_off;
 526         tcmu_flush_dcache_range(entry, sizeof(*entry));
 527
 528         UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
 529         tcmu_flush_dcache_range(mb, sizeof(*mb));
 530
 531         spin_unlock_irq(&udev->cmdr_lock);
 532
 533         /* TODO: only if FLUSH and FUA? */
 534         uio_event_notify(&udev->uio_info);
 535
 536         if (udev->cmd_time_out)
 537                 mod_timer(&udev->timeout, round_jiffies_up(jiffies +
 538                           msecs_to_jiffies(udev->cmd_time_out)));
 539
 540         return TCM_NO_SENSE;
 541 }
 542
 543 static sense_reason_t
 544 tcmu_queue_cmd(struct se_cmd *se_cmd)
 545 {
 546         struct se_device *se_dev = se_cmd->se_dev;
 547         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 548         struct tcmu_cmd *tcmu_cmd;
 549         sense_reason_t ret;
 550
 551         tcmu_cmd = tcmu_alloc_cmd(se_cmd);
 552         if (!tcmu_cmd)
 553                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 554
 555         ret = tcmu_queue_cmd_ring(tcmu_cmd);
 556         if (ret != TCM_NO_SENSE) {
 557                 pr_err("TCMU: Could not queue command\n");
 558                 spin_lock_irq(&udev->commands_lock);
 559                 idr_remove(&udev->commands, tcmu_cmd->cmd_id);
 560                 spin_unlock_irq(&udev->commands_lock);
 561
 562                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 563         }
 564
 565         return ret;
 566 }
 567
 568 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
 569 {
 570         struct se_cmd *se_cmd = cmd->se_cmd;
 571         struct tcmu_dev *udev = cmd->tcmu_dev;
 572
 573         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
 574                 /*
 575                  * cmd has been completed already from timeout, just reclaim
 576                  * data area space and free cmd
 577                  */
 578                 free_data_area(udev, cmd);
 579
 580                 kmem_cache_free(tcmu_cmd_cache, cmd);
 581                 return;
 582         }
 583
 584         if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
 585                 free_data_area(udev, cmd);
 586                 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
 587                         cmd->se_cmd);
 588                 entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
 589         } else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
 590                 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
 591                                se_cmd->scsi_sense_length);
 592                 free_data_area(udev, cmd);
 593         } else if (se_cmd->se_cmd_flags & SCF_BIDI) {
 594                 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
 595
 596                 /* Get Data-In buffer before clean up */
 597                 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
 598                 gather_data_area(udev, bitmap,
 599                         se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents);
 600                 free_data_area(udev, cmd);
 601         } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
 602                 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
 603
 604                 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
 605                 gather_data_area(udev, bitmap,
 606                         se_cmd->t_data_sg, se_cmd->t_data_nents);
 607                 free_data_area(udev, cmd);
 608         } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
 609                 free_data_area(udev, cmd);
 610         } else if (se_cmd->data_direction != DMA_NONE) {
 611                 pr_warn("TCMU: data direction was %d!\n",
 612                         se_cmd->data_direction);
 613         }
 614
 615         target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
 616         cmd->se_cmd = NULL;
 617
 618         kmem_cache_free(tcmu_cmd_cache, cmd);
 619 }
 620
 621 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
 622 {
 623         struct tcmu_mailbox *mb;
 624         unsigned long flags;
 625         int handled = 0;
 626
 627         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
 628                 pr_err("ring broken, not handling completions\n");
 629                 return 0;
 630         }
 631
 632         spin_lock_irqsave(&udev->cmdr_lock, flags);
 633
 634         mb = udev->mb_addr;
 635         tcmu_flush_dcache_range(mb, sizeof(*mb));
 636
 637         while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) {
 638
 639                 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
 640                 struct tcmu_cmd *cmd;
 641
 642                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 643
 644                 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
 645                         UPDATE_HEAD(udev->cmdr_last_cleaned,
 646                                     tcmu_hdr_get_len(entry->hdr.len_op),
 647                                     udev->cmdr_size);
 648                         continue;
 649                 }
 650                 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
 651
 652                 spin_lock(&udev->commands_lock);
 653                 cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
 654                 spin_unlock(&udev->commands_lock);
 655
 656                 if (!cmd) {
 657                         pr_err("cmd_id not found, ring is broken\n");
 658                         set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
 659                         break;
 660                 }
 661
 662                 tcmu_handle_completion(cmd, entry);
 663
 664                 UPDATE_HEAD(udev->cmdr_last_cleaned,
 665                             tcmu_hdr_get_len(entry->hdr.len_op),
 666                             udev->cmdr_size);
 667
 668                 handled++;
 669         }
 670
 671         if (mb->cmd_tail == mb->cmd_head)
 672                 del_timer(&udev->timeout); /* no more pending cmds */
 673
 674         spin_unlock_irqrestore(&udev->cmdr_lock, flags);
 675
 676         wake_up(&udev->wait_cmdr);
 677
 678         return handled;
 679 }
 680
 681 static int tcmu_check_expired_cmd(int id, void *p, void *data)
 682 {
 683         struct tcmu_cmd *cmd = p;
 684
 685         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
 686                 return 0;
 687
 688         if (!time_after(jiffies, cmd->deadline))
 689                 return 0;
 690
 691         set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
 692         target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
 693         cmd->se_cmd = NULL;
 694
 695         return 0;
 696 }
 697
 698 static void tcmu_device_timedout(unsigned long data)
 699 {
 700         struct tcmu_dev *udev = (struct tcmu_dev *)data;
 701         unsigned long flags;
 702         int handled;
 703
 704         handled = tcmu_handle_completions(udev);
 705
 706         pr_warn("%d completions handled from timeout\n", handled);
 707
 708         spin_lock_irqsave(&udev->commands_lock, flags);
 709         idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
 710         spin_unlock_irqrestore(&udev->commands_lock, flags);
 711
 712         /*
 713          * We don't need to wakeup threads on wait_cmdr since they have their
 714          * own timeout.
 715          */
 716 }
 717
 718 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
 719 {
 720         struct tcmu_hba *tcmu_hba;
 721
 722         tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
 723         if (!tcmu_hba)
 724                 return -ENOMEM;
 725
 726         tcmu_hba->host_id = host_id;
 727         hba->hba_ptr = tcmu_hba;
 728
 729         return 0;
 730 }
 731
 732 static void tcmu_detach_hba(struct se_hba *hba)
 733 {
 734         kfree(hba->hba_ptr);
 735         hba->hba_ptr = NULL;
 736 }
 737
 738 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
 739 {
 740         struct tcmu_dev *udev;
 741
 742         udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
 743         if (!udev)
 744                 return NULL;
 745
 746         udev->name = kstrdup(name, GFP_KERNEL);
 747         if (!udev->name) {
 748                 kfree(udev);
 749                 return NULL;
 750         }
 751
 752         udev->hba = hba;
 753         udev->cmd_time_out = TCMU_TIME_OUT;
 754
 755         init_waitqueue_head(&udev->wait_cmdr);
 756         spin_lock_init(&udev->cmdr_lock);
 757
 758         idr_init(&udev->commands);
 759         spin_lock_init(&udev->commands_lock);
 760
 761         setup_timer(&udev->timeout, tcmu_device_timedout,
 762                 (unsigned long)udev);
 763
 764         return &udev->se_dev;
 765 }
 766
 767 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
 768 {
 769         struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
 770
 771         tcmu_handle_completions(tcmu_dev);
 772
 773         return 0;
 774 }
 775
 776 /*
 777  * mmap code from uio.c. Copied here because we want to hook mmap()
 778  * and this stuff must come along.
 779  */
 780 static int tcmu_find_mem_index(struct vm_area_struct *vma)
 781 {
 782         struct tcmu_dev *udev = vma->vm_private_data;
 783         struct uio_info *info = &udev->uio_info;
 784
 785         if (vma->vm_pgoff < MAX_UIO_MAPS) {
 786                 if (info->mem[vma->vm_pgoff].size == 0)
 787                         return -1;
 788                 return (int)vma->vm_pgoff;
 789         }
 790         return -1;
 791 }
 792
 793 static int tcmu_vma_fault(struct vm_fault *vmf)
 794 {
 795         struct tcmu_dev *udev = vmf->vma->vm_private_data;
 796         struct uio_info *info = &udev->uio_info;
 797         struct page *page;
 798         unsigned long offset;
 799         void *addr;
 800
 801         int mi = tcmu_find_mem_index(vmf->vma);
 802         if (mi < 0)
 803                 return VM_FAULT_SIGBUS;
 804
 805         /*
 806          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 807          * to use mem[N].
 808          */
 809         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 810
 811         addr = (void *)(unsigned long)info->mem[mi].addr + offset;
 812         if (info->mem[mi].memtype == UIO_MEM_LOGICAL)
 813                 page = virt_to_page(addr);
 814         else
 815                 page = vmalloc_to_page(addr);
 816         get_page(page);
 817         vmf->page = page;
 818         return 0;
 819 }
 820
 821 static const struct vm_operations_struct tcmu_vm_ops = {
 822         .fault = tcmu_vma_fault,
 823 };
 824
 825 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
 826 {
 827         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 828
 829         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 830         vma->vm_ops = &tcmu_vm_ops;
 831
 832         vma->vm_private_data = udev;
 833
 834         /* Ensure the mmap is exactly the right size */
 835         if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
 836                 return -EINVAL;
 837
 838         return 0;
 839 }
 840
 841 static int tcmu_open(struct uio_info *info, struct inode *inode)
 842 {
 843         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 844
 845         /* O_EXCL not supported for char devs, so fake it? */
 846         if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
 847                 return -EBUSY;
 848
 849         pr_debug("open\n");
 850
 851         return 0;
 852 }
 853
 854 static int tcmu_release(struct uio_info *info, struct inode *inode)
 855 {
 856         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 857
 858         clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
 859
 860         pr_debug("close\n");
 861
 862         return 0;
 863 }
 864
 865 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor)
 866 {
 867         struct sk_buff *skb;
 868         void *msg_header;
 869         int ret = -ENOMEM;
 870
 871         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 872         if (!skb)
 873                 return ret;
 874
 875         msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
 876         if (!msg_header)
 877                 goto free_skb;
 878
 879         ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name);
 880         if (ret < 0)
 881                 goto free_skb;
 882
 883         ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor);
 884         if (ret < 0)
 885                 goto free_skb;
 886
 887         genlmsg_end(skb, msg_header);
 888
 889         ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
 890                                 TCMU_MCGRP_CONFIG, GFP_KERNEL);
 891
 892         /* We don't care if no one is listening */
 893         if (ret == -ESRCH)
 894                 ret = 0;
 895
 896         return ret;
 897 free_skb:
 898         nlmsg_free(skb);
 899         return ret;
 900 }
 901
 902 static int tcmu_configure_device(struct se_device *dev)
 903 {
 904         struct tcmu_dev *udev = TCMU_DEV(dev);
 905         struct tcmu_hba *hba = udev->hba->hba_ptr;
 906         struct uio_info *info;
 907         struct tcmu_mailbox *mb;
 908         size_t size;
 909         size_t used;
 910         int ret = 0;
 911         char *str;
 912
 913         info = &udev->uio_info;
 914
 915         size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
 916                         udev->dev_config);
 917         size += 1; /* for \0 */
 918         str = kmalloc(size, GFP_KERNEL);
 919         if (!str)
 920                 return -ENOMEM;
 921
 922         used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
 923
 924         if (udev->dev_config[0])
 925                 snprintf(str + used, size - used, "/%s", udev->dev_config);
 926
 927         info->name = str;
 928
 929         udev->mb_addr = vzalloc(TCMU_RING_SIZE);
 930         if (!udev->mb_addr) {
 931                 ret = -ENOMEM;
 932                 goto err_vzalloc;
 933         }
 934
 935         /* mailbox fits in first part of CMDR space */
 936         udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
 937         udev->data_off = CMDR_SIZE;
 938         udev->data_size = TCMU_RING_SIZE - CMDR_SIZE;
 939
 940         mb = udev->mb_addr;
 941         mb->version = TCMU_MAILBOX_VERSION;
 942         mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC;
 943         mb->cmdr_off = CMDR_OFF;
 944         mb->cmdr_size = udev->cmdr_size;
 945
 946         WARN_ON(!PAGE_ALIGNED(udev->data_off));
 947         WARN_ON(udev->data_size % PAGE_SIZE);
 948         WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
 949
 950         info->version = __stringify(TCMU_MAILBOX_VERSION);
 951
 952         info->mem[0].name = "tcm-user command & data buffer";
 953         info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
 954         info->mem[0].size = TCMU_RING_SIZE;
 955         info->mem[0].memtype = UIO_MEM_VIRTUAL;
 956
 957         info->irqcontrol = tcmu_irqcontrol;
 958         info->irq = UIO_IRQ_CUSTOM;
 959
 960         info->mmap = tcmu_mmap;
 961         info->open = tcmu_open;
 962         info->release = tcmu_release;
 963
 964         ret = uio_register_device(tcmu_root_device, info);
 965         if (ret)
 966                 goto err_register;
 967
 968         /* User can set hw_block_size before enable the device */
 969         if (dev->dev_attrib.hw_block_size == 0)
 970                 dev->dev_attrib.hw_block_size = 512;
 971         /* Other attributes can be configured in userspace */
 972         if (!dev->dev_attrib.hw_max_sectors)
 973                 dev->dev_attrib.hw_max_sectors = 128;
 974         dev->dev_attrib.hw_queue_depth = 128;
 975
 976         ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
 977                                  udev->uio_info.uio_dev->minor);
 978         if (ret)
 979                 goto err_netlink;
 980
 981         return 0;
 982
 983 err_netlink:
 984         uio_unregister_device(&udev->uio_info);
 985 err_register:
 986         vfree(udev->mb_addr);
 987 err_vzalloc:
 988         kfree(info->name);
 989
 990         return ret;
 991 }
 992
 993 static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
 994 {
 995         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
 996                 kmem_cache_free(tcmu_cmd_cache, cmd);
 997                 return 0;
 998         }
 999         return -EINVAL;
1000 }
1001
1002 static void tcmu_dev_call_rcu(struct rcu_head *p)
1003 {
1004         struct se_device *dev = container_of(p, struct se_device, rcu_head);
1005         struct tcmu_dev *udev = TCMU_DEV(dev);
1006
1007         kfree(udev);
1008 }
1009
1010 static bool tcmu_dev_configured(struct tcmu_dev *udev)
1011 {
1012         return udev->uio_info.uio_dev ? true : false;
1013 }
1014
1015 static void tcmu_free_device(struct se_device *dev)
1016 {
1017         struct tcmu_dev *udev = TCMU_DEV(dev);
1018         struct tcmu_cmd *cmd;
1019         bool all_expired = true;
1020         int i;
1021
1022         del_timer_sync(&udev->timeout);
1023
1024         vfree(udev->mb_addr);
1025
1026         /* Upper layer should drain all requests before calling this */
1027         spin_lock_irq(&udev->commands_lock);
1028         idr_for_each_entry(&udev->commands, cmd, i) {
1029                 if (tcmu_check_and_free_pending_cmd(cmd) != 0)
1030                         all_expired = false;
1031         }
1032         idr_destroy(&udev->commands);
1033         spin_unlock_irq(&udev->commands_lock);
1034         WARN_ON(!all_expired);
1035
1036         if (tcmu_dev_configured(udev)) {
1037                 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
1038                                    udev->uio_info.uio_dev->minor);
1039
1040                 uio_unregister_device(&udev->uio_info);
1041                 kfree(udev->uio_info.name);
1042                 kfree(udev->name);
1043         }
1044         call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
1045 }
1046
1047 enum {
1048         Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
1049         Opt_cmd_time_out, Opt_err,
1050 };
1051
1052 static match_table_t tokens = {
1053         {Opt_dev_config, "dev_config=%s"},
1054         {Opt_dev_size, "dev_size=%u"},
1055         {Opt_hw_block_size, "hw_block_size=%u"},
1056         {Opt_hw_max_sectors, "hw_max_sectors=%u"},
1057         {Opt_cmd_time_out, "cmd_time_out=%u"},
1058         {Opt_err, NULL}
1059 };
1060
1061 static int tcmu_set_dev_attrib(substring_t *arg, u32 *dev_attrib)
1062 {
1063         unsigned long tmp_ul;
1064         char *arg_p;
1065         int ret;
1066
1067         arg_p = match_strdup(arg);
1068         if (!arg_p)
1069                 return -ENOMEM;
1070
1071         ret = kstrtoul(arg_p, 0, &tmp_ul);
1072         kfree(arg_p);
1073         if (ret < 0) {
1074                 pr_err("kstrtoul() failed for dev attrib\n");
1075                 return ret;
1076         }
1077         if (!tmp_ul) {
1078                 pr_err("dev attrib must be nonzero\n");
1079                 return -EINVAL;
1080         }
1081         *dev_attrib = tmp_ul;
1082         return 0;
1083 }
1084
1085 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
1086                 const char *page, ssize_t count)
1087 {
1088         struct tcmu_dev *udev = TCMU_DEV(dev);
1089         char *orig, *ptr, *opts, *arg_p;
1090         substring_t args[MAX_OPT_ARGS];
1091         int ret = 0, token;
1092
1093         opts = kstrdup(page, GFP_KERNEL);
1094         if (!opts)
1095                 return -ENOMEM;
1096
1097         orig = opts;
1098
1099         while ((ptr = strsep(&opts, ",\n")) != NULL) {
1100                 if (!*ptr)
1101                         continue;
1102
1103                 token = match_token(ptr, tokens, args);
1104                 switch (token) {
1105                 case Opt_dev_config:
1106                         if (match_strlcpy(udev->dev_config, &args[0],
1107                                           TCMU_CONFIG_LEN) == 0) {
1108                                 ret = -EINVAL;
1109                                 break;
1110                         }
1111                         pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
1112                         break;
1113                 case Opt_dev_size:
1114                         arg_p = match_strdup(&args[0]);
1115                         if (!arg_p) {
1116                                 ret = -ENOMEM;
1117                                 break;
1118                         }
1119                         ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
1120                         kfree(arg_p);
1121                         if (ret < 0)
1122                                 pr_err("kstrtoul() failed for dev_size=\n");
1123                         break;
1124                 case Opt_cmd_time_out:
1125                         if (tcmu_dev_configured(udev)) {
1126                                 pr_err("Can not update cmd_time_out after device has been configured.\n");
1127                                 ret = -EINVAL;
1128                                 break;
1129                         }
1130                         arg_p = match_strdup(&args[0]);
1131                         if (!arg_p) {
1132                                 ret = -ENOMEM;
1133                                 break;
1134                         }
1135                         ret = kstrtouint(arg_p, 0, &udev->cmd_time_out);
1136                         kfree(arg_p);
1137                         if (ret < 0)
1138                                 pr_err("kstrtouint() failed for cmd_time_out=\n");
1139                         udev->cmd_time_out *= MSEC_PER_SEC;
1140                         break;
1141                 case Opt_hw_block_size:
1142                         ret = tcmu_set_dev_attrib(&args[0],
1143                                         &(dev->dev_attrib.hw_block_size));
1144                         break;
1145                 case Opt_hw_max_sectors:
1146                         ret = tcmu_set_dev_attrib(&args[0],
1147                                         &(dev->dev_attrib.hw_max_sectors));
1148                         break;
1149                 default:
1150                         break;
1151                 }
1152
1153                 if (ret)
1154                         break;
1155         }
1156
1157         kfree(orig);
1158         return (!ret) ? count : ret;
1159 }
1160
1161 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
1162 {
1163         struct tcmu_dev *udev = TCMU_DEV(dev);
1164         ssize_t bl = 0;
1165
1166         bl = sprintf(b + bl, "Config: %s ",
1167                      udev->dev_config[0] ? udev->dev_config : "NULL");
1168         bl += sprintf(b + bl, "Size: %zu ", udev->dev_size);
1169         bl += sprintf(b + bl, "Cmd Time Out: %lu\n",
1170                       udev->cmd_time_out / MSEC_PER_SEC);
1171
1172         return bl;
1173 }
1174
1175 static sector_t tcmu_get_blocks(struct se_device *dev)
1176 {
1177         struct tcmu_dev *udev = TCMU_DEV(dev);
1178
1179         return div_u64(udev->dev_size - dev->dev_attrib.block_size,
1180                        dev->dev_attrib.block_size);
1181 }
1182
1183 static sense_reason_t
1184 tcmu_parse_cdb(struct se_cmd *cmd)
1185 {
1186         return passthrough_parse_cdb(cmd, tcmu_queue_cmd);
1187 }
1188
1189 static const struct target_backend_ops tcmu_ops = {
1190         .name                   = "user",
1191         .owner                  = THIS_MODULE,
1192         .transport_flags        = TRANSPORT_FLAG_PASSTHROUGH,
1193         .attach_hba             = tcmu_attach_hba,
1194         .detach_hba             = tcmu_detach_hba,
1195         .alloc_device           = tcmu_alloc_device,
1196         .configure_device       = tcmu_configure_device,
1197         .free_device            = tcmu_free_device,
1198         .parse_cdb              = tcmu_parse_cdb,
1199         .set_configfs_dev_params = tcmu_set_configfs_dev_params,
1200         .show_configfs_dev_params = tcmu_show_configfs_dev_params,
1201         .get_device_type        = sbc_get_device_type,
1202         .get_blocks             = tcmu_get_blocks,
1203         .tb_dev_attrib_attrs    = passthrough_attrib_attrs,
1204 };
1205
1206 static int __init tcmu_module_init(void)
1207 {
1208         int ret;
1209
1210         BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
1211
1212         tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
1213                                 sizeof(struct tcmu_cmd),
1214                                 __alignof__(struct tcmu_cmd),
1215                                 0, NULL);
1216         if (!tcmu_cmd_cache)
1217                 return -ENOMEM;
1218
1219         tcmu_root_device = root_device_register("tcm_user");
1220         if (IS_ERR(tcmu_root_device)) {
1221                 ret = PTR_ERR(tcmu_root_device);
1222                 goto out_free_cache;
1223         }
1224
1225         ret = genl_register_family(&tcmu_genl_family);
1226         if (ret < 0) {
1227                 goto out_unreg_device;
1228         }
1229
1230         ret = transport_backend_register(&tcmu_ops);
1231         if (ret)
1232                 goto out_unreg_genl;
1233
1234         return 0;
1235
1236 out_unreg_genl:
1237         genl_unregister_family(&tcmu_genl_family);
1238 out_unreg_device:
1239         root_device_unregister(tcmu_root_device);
1240 out_free_cache:
1241         kmem_cache_destroy(tcmu_cmd_cache);
1242
1243         return ret;
1244 }
1245
1246 static void __exit tcmu_module_exit(void)
1247 {
1248         target_backend_unregister(&tcmu_ops);
1249         genl_unregister_family(&tcmu_genl_family);
1250         root_device_unregister(tcmu_root_device);
1251         kmem_cache_destroy(tcmu_cmd_cache);
1252 }
1253
1254 MODULE_DESCRIPTION("TCM USER subsystem plugin");
1255 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
1256 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
1257 MODULE_LICENSE("GPL");
1258
1259 module_init(tcmu_module_init);
1260 module_exit(tcmu_module_exit);