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