drivers/target/target_core_user.c

   1 /*
   2  * Copyright (C) 2013 Shaohua Li <shli@kernel.org>
   3  * Copyright (C) 2014 Red Hat, Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #include <linux/spinlock.h>
  20 #include <linux/module.h>
  21 #include <linux/idr.h>
  22 #include <linux/timer.h>
  23 #include <linux/parser.h>
  24 #include <scsi/scsi.h>
  25 #include <scsi/scsi_host.h>
  26 #include <linux/uio_driver.h>
  27 #include <net/genetlink.h>
  28 #include <target/target_core_base.h>
  29 #include <target/target_core_fabric.h>
  30 #include <target/target_core_backend.h>
  31 #include <target/target_core_backend_configfs.h>
  32
  33 #include <linux/target_core_user.h>
  34
  35 /*
  36  * Define a shared-memory interface for LIO to pass SCSI commands and
  37  * data to userspace for processing. This is to allow backends that
  38  * are too complex for in-kernel support to be possible.
  39  *
  40  * It uses the UIO framework to do a lot of the device-creation and
  41  * introspection work for us.
  42  *
  43  * See the .h file for how the ring is laid out. Note that while the
  44  * command ring is defined, the particulars of the data area are
  45  * not. Offset values in the command entry point to other locations
  46  * internal to the mmap()ed area. There is separate space outside the
  47  * command ring for data buffers. This leaves maximum flexibility for
  48  * moving buffer allocations, or even page flipping or other
  49  * allocation techniques, without altering the command ring layout.
  50  *
  51  * SECURITY:
  52  * The user process must be assumed to be malicious. There's no way to
  53  * prevent it breaking the command ring protocol if it wants, but in
  54  * order to prevent other issues we must only ever read *data* from
  55  * the shared memory area, not offsets or sizes. This applies to
  56  * command ring entries as well as the mailbox. Extra code needed for
  57  * this may have a 'UAM' comment.
  58  */
  59
  60
  61 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
  62
  63 #define CMDR_SIZE (16 * 4096)
  64 #define DATA_SIZE (257 * 4096)
  65
  66 #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
  67
  68 static struct device *tcmu_root_device;
  69
  70 struct tcmu_hba {
  71         u32 host_id;
  72 };
  73
  74 /* User wants all cmds or just some */
  75 enum passthru_level {
  76         TCMU_PASS_ALL = 0,
  77         TCMU_PASS_IO,
  78         TCMU_PASS_INVALID,
  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         enum passthru_level pass_level;
  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 ring from start of mb */
 101         size_t data_off;
 102         size_t data_size;
 103         /* Ring head + tail values. */
 104         /* Must add data_off and mb_addr to get the address */
 105         size_t data_head;
 106         size_t data_tail;
 107
 108         wait_queue_head_t wait_cmdr;
 109         /* TODO should this be a mutex? */
 110         spinlock_t cmdr_lock;
 111
 112         struct idr commands;
 113         spinlock_t commands_lock;
 114
 115         struct timer_list timeout;
 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->data_length when cleaning up expired cmds, because if
 131            cmd has been completed then accessing se_cmd is off limits */
 132         size_t data_length;
 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 = {
 153         .id = GENL_ID_GENERATE,
 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 };
 161
 162 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
 163 {
 164         struct se_device *se_dev = se_cmd->se_dev;
 165         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 166         struct tcmu_cmd *tcmu_cmd;
 167         int cmd_id;
 168
 169         tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
 170         if (!tcmu_cmd)
 171                 return NULL;
 172
 173         tcmu_cmd->se_cmd = se_cmd;
 174         tcmu_cmd->tcmu_dev = udev;
 175         tcmu_cmd->data_length = se_cmd->data_length;
 176
 177         tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT);
 178
 179         idr_preload(GFP_KERNEL);
 180         spin_lock_irq(&udev->commands_lock);
 181         cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0,
 182                 USHRT_MAX, GFP_NOWAIT);
 183         spin_unlock_irq(&udev->commands_lock);
 184         idr_preload_end();
 185
 186         if (cmd_id < 0) {
 187                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 188                 return NULL;
 189         }
 190         tcmu_cmd->cmd_id = cmd_id;
 191
 192         return tcmu_cmd;
 193 }
 194
 195 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
 196 {
 197         unsigned long offset = (unsigned long) vaddr & ~PAGE_MASK;
 198
 199         size = round_up(size+offset, PAGE_SIZE);
 200         vaddr -= offset;
 201
 202         while (size) {
 203                 flush_dcache_page(virt_to_page(vaddr));
 204                 size -= PAGE_SIZE;
 205         }
 206 }
 207
 208 /*
 209  * Some ring helper functions. We don't assume size is a power of 2 so
 210  * we can't use circ_buf.h.
 211  */
 212 static inline size_t spc_used(size_t head, size_t tail, size_t size)
 213 {
 214         int diff = head - tail;
 215
 216         if (diff >= 0)
 217                 return diff;
 218         else
 219                 return size + diff;
 220 }
 221
 222 static inline size_t spc_free(size_t head, size_t tail, size_t size)
 223 {
 224         /* Keep 1 byte unused or we can't tell full from empty */
 225         return (size - spc_used(head, tail, size) - 1);
 226 }
 227
 228 static inline size_t head_to_end(size_t head, size_t size)
 229 {
 230         return size - head;
 231 }
 232
 233 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
 234
 235 /*
 236  * We can't queue a command until we have space available on the cmd ring *and* space
 237  * space avail on the data ring.
 238  *
 239  * Called with ring lock held.
 240  */
 241 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed)
 242 {
 243         struct tcmu_mailbox *mb = udev->mb_addr;
 244         size_t space;
 245         u32 cmd_head;
 246         size_t cmd_needed;
 247
 248         tcmu_flush_dcache_range(mb, sizeof(*mb));
 249
 250         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 251
 252         /*
 253          * If cmd end-of-ring space is too small then we need space for a NOP plus
 254          * original cmd - cmds are internally contiguous.
 255          */
 256         if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
 257                 cmd_needed = cmd_size;
 258         else
 259                 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
 260
 261         space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
 262         if (space < cmd_needed) {
 263                 pr_debug("no cmd space: %u %u %u\n", cmd_head,
 264                        udev->cmdr_last_cleaned, udev->cmdr_size);
 265                 return false;
 266         }
 267
 268         space = spc_free(udev->data_head, udev->data_tail, udev->data_size);
 269         if (space < data_needed) {
 270                 pr_debug("no data space: %zu %zu %zu\n", udev->data_head,
 271                        udev->data_tail, udev->data_size);
 272                 return false;
 273         }
 274
 275         return true;
 276 }
 277
 278 static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
 279 {
 280         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
 281         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 282         size_t base_command_size, command_size;
 283         struct tcmu_mailbox *mb;
 284         struct tcmu_cmd_entry *entry;
 285         int i;
 286         struct scatterlist *sg;
 287         struct iovec *iov;
 288         int iov_cnt = 0;
 289         uint32_t cmd_head;
 290         uint64_t cdb_off;
 291
 292         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
 293                 return -EINVAL;
 294
 295         /*
 296          * Must be a certain minimum size for response sense info, but
 297          * also may be larger if the iov array is large.
 298          *
 299          * iovs = sgl_nents+1, for end-of-ring case, plus another 1
 300          * b/c size == offsetof one-past-element.
 301         */
 302         base_command_size = max(offsetof(struct tcmu_cmd_entry,
 303                                          req.iov[se_cmd->t_data_nents + 2]),
 304                                 sizeof(struct tcmu_cmd_entry));
 305         command_size = base_command_size
 306                 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
 307
 308         WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
 309
 310         spin_lock_irq(&udev->cmdr_lock);
 311
 312         mb = udev->mb_addr;
 313         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 314         if ((command_size > (udev->cmdr_size / 2))
 315             || tcmu_cmd->data_length > (udev->data_size - 1))
 316                 pr_warn("TCMU: Request of size %zu/%zu may be too big for %u/%zu "
 317                         "cmd/data ring buffers\n", command_size, tcmu_cmd->data_length,
 318                         udev->cmdr_size, udev->data_size);
 319
 320         while (!is_ring_space_avail(udev, command_size, tcmu_cmd->data_length)) {
 321                 int ret;
 322                 DEFINE_WAIT(__wait);
 323
 324                 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
 325
 326                 pr_debug("sleeping for ring space\n");
 327                 spin_unlock_irq(&udev->cmdr_lock);
 328                 ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
 329                 finish_wait(&udev->wait_cmdr, &__wait);
 330                 if (!ret) {
 331                         pr_warn("tcmu: command timed out\n");
 332                         return -ETIMEDOUT;
 333                 }
 334
 335                 spin_lock_irq(&udev->cmdr_lock);
 336
 337                 /* We dropped cmdr_lock, cmd_head is stale */
 338                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 339         }
 340
 341         /* Insert a PAD if end-of-ring space is too small */
 342         if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
 343                 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
 344
 345                 entry = (void *) mb + CMDR_OFF + cmd_head;
 346                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 347                 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
 348                 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
 349                 entry->hdr.cmd_id = 0; /* not used for PAD */
 350                 entry->hdr.kflags = 0;
 351                 entry->hdr.uflags = 0;
 352
 353                 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
 354
 355                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 356                 WARN_ON(cmd_head != 0);
 357         }
 358
 359         entry = (void *) mb + CMDR_OFF + cmd_head;
 360         tcmu_flush_dcache_range(entry, sizeof(*entry));
 361         tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
 362         tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
 363         entry->hdr.cmd_id = tcmu_cmd->cmd_id;
 364         entry->hdr.kflags = 0;
 365         entry->hdr.uflags = 0;
 366
 367         /*
 368          * Fix up iovecs, and handle if allocation in data ring wrapped.
 369          */
 370         iov = &entry->req.iov[0];
 371         for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) {
 372                 size_t copy_bytes = min((size_t)sg->length,
 373                                      head_to_end(udev->data_head, udev->data_size));
 374                 void *from = kmap_atomic(sg_page(sg)) + sg->offset;
 375                 void *to = (void *) mb + udev->data_off + udev->data_head;
 376
 377                 if (tcmu_cmd->se_cmd->data_direction == DMA_TO_DEVICE) {
 378                         memcpy(to, from, copy_bytes);
 379                         tcmu_flush_dcache_range(to, copy_bytes);
 380                 }
 381
 382                 /* Even iov_base is relative to mb_addr */
 383                 iov->iov_len = copy_bytes;
 384                 iov->iov_base = (void __user *) udev->data_off +
 385                                                 udev->data_head;
 386                 iov_cnt++;
 387                 iov++;
 388
 389                 UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
 390
 391                 /* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */
 392                 if (sg->length != copy_bytes) {
 393                         from += copy_bytes;
 394                         copy_bytes = sg->length - copy_bytes;
 395
 396                         iov->iov_len = copy_bytes;
 397                         iov->iov_base = (void __user *) udev->data_off +
 398                                                         udev->data_head;
 399
 400                         if (se_cmd->data_direction == DMA_TO_DEVICE) {
 401                                 to = (void *) mb + udev->data_off + udev->data_head;
 402                                 memcpy(to, from, copy_bytes);
 403                                 tcmu_flush_dcache_range(to, copy_bytes);
 404                         }
 405
 406                         iov_cnt++;
 407                         iov++;
 408
 409                         UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
 410                 }
 411
 412                 kunmap_atomic(from);
 413         }
 414         entry->req.iov_cnt = iov_cnt;
 415         entry->req.iov_bidi_cnt = 0;
 416         entry->req.iov_dif_cnt = 0;
 417
 418         /* All offsets relative to mb_addr, not start of entry! */
 419         cdb_off = CMDR_OFF + cmd_head + base_command_size;
 420         memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
 421         entry->req.cdb_off = cdb_off;
 422         tcmu_flush_dcache_range(entry, sizeof(*entry));
 423
 424         UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
 425         tcmu_flush_dcache_range(mb, sizeof(*mb));
 426
 427         spin_unlock_irq(&udev->cmdr_lock);
 428
 429         /* TODO: only if FLUSH and FUA? */
 430         uio_event_notify(&udev->uio_info);
 431
 432         mod_timer(&udev->timeout,
 433                 round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT)));
 434
 435         return 0;
 436 }
 437
 438 static int tcmu_queue_cmd(struct se_cmd *se_cmd)
 439 {
 440         struct se_device *se_dev = se_cmd->se_dev;
 441         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 442         struct tcmu_cmd *tcmu_cmd;
 443         int ret;
 444
 445         tcmu_cmd = tcmu_alloc_cmd(se_cmd);
 446         if (!tcmu_cmd)
 447                 return -ENOMEM;
 448
 449         ret = tcmu_queue_cmd_ring(tcmu_cmd);
 450         if (ret < 0) {
 451                 pr_err("TCMU: Could not queue command\n");
 452                 spin_lock_irq(&udev->commands_lock);
 453                 idr_remove(&udev->commands, tcmu_cmd->cmd_id);
 454                 spin_unlock_irq(&udev->commands_lock);
 455
 456                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 457         }
 458
 459         return ret;
 460 }
 461
 462 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
 463 {
 464         struct se_cmd *se_cmd = cmd->se_cmd;
 465         struct tcmu_dev *udev = cmd->tcmu_dev;
 466
 467         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
 468                 /* cmd has been completed already from timeout, just reclaim data
 469                    ring space */
 470                 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
 471                 return;
 472         }
 473
 474         if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
 475                 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
 476                 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
 477                         cmd->se_cmd);
 478                 transport_generic_request_failure(cmd->se_cmd,
 479                         TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
 480                 cmd->se_cmd = NULL;
 481                 kmem_cache_free(tcmu_cmd_cache, cmd);
 482                 return;
 483         }
 484
 485         if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
 486                 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
 487                                se_cmd->scsi_sense_length);
 488
 489                 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
 490         }
 491         else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
 492                 struct scatterlist *sg;
 493                 int i;
 494
 495                 /* It'd be easier to look at entry's iovec again, but UAM */
 496                 for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) {
 497                         size_t copy_bytes;
 498                         void *to;
 499                         void *from;
 500
 501                         copy_bytes = min((size_t)sg->length,
 502                                          head_to_end(udev->data_tail, udev->data_size));
 503
 504                         to = kmap_atomic(sg_page(sg)) + sg->offset;
 505                         WARN_ON(sg->length + sg->offset > PAGE_SIZE);
 506                         from = (void *) udev->mb_addr + udev->data_off + udev->data_tail;
 507                         tcmu_flush_dcache_range(from, copy_bytes);
 508                         memcpy(to, from, copy_bytes);
 509
 510                         UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size);
 511
 512                         /* Uh oh, wrapped the data buffer for this sg's data */
 513                         if (sg->length != copy_bytes) {
 514                                 from = (void *) udev->mb_addr + udev->data_off + udev->data_tail;
 515                                 WARN_ON(udev->data_tail);
 516                                 to += copy_bytes;
 517                                 copy_bytes = sg->length - copy_bytes;
 518                                 tcmu_flush_dcache_range(from, copy_bytes);
 519                                 memcpy(to, from, copy_bytes);
 520
 521                                 UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size);
 522                         }
 523
 524                         kunmap_atomic(to);
 525                 }
 526
 527         } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
 528                 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
 529         } else {
 530                 pr_warn("TCMU: data direction was %d!\n", se_cmd->data_direction);
 531         }
 532
 533         target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
 534         cmd->se_cmd = NULL;
 535
 536         kmem_cache_free(tcmu_cmd_cache, cmd);
 537 }
 538
 539 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
 540 {
 541         struct tcmu_mailbox *mb;
 542         LIST_HEAD(cpl_cmds);
 543         unsigned long flags;
 544         int handled = 0;
 545
 546         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
 547                 pr_err("ring broken, not handling completions\n");
 548                 return 0;
 549         }
 550
 551         spin_lock_irqsave(&udev->cmdr_lock, flags);
 552
 553         mb = udev->mb_addr;
 554         tcmu_flush_dcache_range(mb, sizeof(*mb));
 555
 556         while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) {
 557
 558                 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
 559                 struct tcmu_cmd *cmd;
 560
 561                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 562
 563                 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
 564                         UPDATE_HEAD(udev->cmdr_last_cleaned,
 565                                     tcmu_hdr_get_len(entry->hdr.len_op),
 566                                     udev->cmdr_size);
 567                         continue;
 568                 }
 569                 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
 570
 571                 spin_lock(&udev->commands_lock);
 572                 cmd = idr_find(&udev->commands, entry->hdr.cmd_id);
 573                 if (cmd)
 574                         idr_remove(&udev->commands, cmd->cmd_id);
 575                 spin_unlock(&udev->commands_lock);
 576
 577                 if (!cmd) {
 578                         pr_err("cmd_id not found, ring is broken\n");
 579                         set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
 580                         break;
 581                 }
 582
 583                 tcmu_handle_completion(cmd, entry);
 584
 585                 UPDATE_HEAD(udev->cmdr_last_cleaned,
 586                             tcmu_hdr_get_len(entry->hdr.len_op),
 587                             udev->cmdr_size);
 588
 589                 handled++;
 590         }
 591
 592         if (mb->cmd_tail == mb->cmd_head)
 593                 del_timer(&udev->timeout); /* no more pending cmds */
 594
 595         spin_unlock_irqrestore(&udev->cmdr_lock, flags);
 596
 597         wake_up(&udev->wait_cmdr);
 598
 599         return handled;
 600 }
 601
 602 static int tcmu_check_expired_cmd(int id, void *p, void *data)
 603 {
 604         struct tcmu_cmd *cmd = p;
 605
 606         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
 607                 return 0;
 608
 609         if (!time_after(cmd->deadline, jiffies))
 610                 return 0;
 611
 612         set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
 613         target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
 614         cmd->se_cmd = NULL;
 615
 616         kmem_cache_free(tcmu_cmd_cache, cmd);
 617
 618         return 0;
 619 }
 620
 621 static void tcmu_device_timedout(unsigned long data)
 622 {
 623         struct tcmu_dev *udev = (struct tcmu_dev *)data;
 624         unsigned long flags;
 625         int handled;
 626
 627         handled = tcmu_handle_completions(udev);
 628
 629         pr_warn("%d completions handled from timeout\n", handled);
 630
 631         spin_lock_irqsave(&udev->commands_lock, flags);
 632         idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
 633         spin_unlock_irqrestore(&udev->commands_lock, flags);
 634
 635         /*
 636          * We don't need to wakeup threads on wait_cmdr since they have their
 637          * own timeout.
 638          */
 639 }
 640
 641 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
 642 {
 643         struct tcmu_hba *tcmu_hba;
 644
 645         tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
 646         if (!tcmu_hba)
 647                 return -ENOMEM;
 648
 649         tcmu_hba->host_id = host_id;
 650         hba->hba_ptr = tcmu_hba;
 651
 652         return 0;
 653 }
 654
 655 static void tcmu_detach_hba(struct se_hba *hba)
 656 {
 657         kfree(hba->hba_ptr);
 658         hba->hba_ptr = NULL;
 659 }
 660
 661 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
 662 {
 663         struct tcmu_dev *udev;
 664
 665         udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
 666         if (!udev)
 667                 return NULL;
 668
 669         udev->name = kstrdup(name, GFP_KERNEL);
 670         if (!udev->name) {
 671                 kfree(udev);
 672                 return NULL;
 673         }
 674
 675         udev->hba = hba;
 676
 677         init_waitqueue_head(&udev->wait_cmdr);
 678         spin_lock_init(&udev->cmdr_lock);
 679
 680         idr_init(&udev->commands);
 681         spin_lock_init(&udev->commands_lock);
 682
 683         setup_timer(&udev->timeout, tcmu_device_timedout,
 684                 (unsigned long)udev);
 685
 686         udev->pass_level = TCMU_PASS_ALL;
 687
 688         return &udev->se_dev;
 689 }
 690
 691 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
 692 {
 693         struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
 694
 695         tcmu_handle_completions(tcmu_dev);
 696
 697         return 0;
 698 }
 699
 700 /*
 701  * mmap code from uio.c. Copied here because we want to hook mmap()
 702  * and this stuff must come along.
 703  */
 704 static int tcmu_find_mem_index(struct vm_area_struct *vma)
 705 {
 706         struct tcmu_dev *udev = vma->vm_private_data;
 707         struct uio_info *info = &udev->uio_info;
 708
 709         if (vma->vm_pgoff < MAX_UIO_MAPS) {
 710                 if (info->mem[vma->vm_pgoff].size == 0)
 711                         return -1;
 712                 return (int)vma->vm_pgoff;
 713         }
 714         return -1;
 715 }
 716
 717 static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 718 {
 719         struct tcmu_dev *udev = vma->vm_private_data;
 720         struct uio_info *info = &udev->uio_info;
 721         struct page *page;
 722         unsigned long offset;
 723         void *addr;
 724
 725         int mi = tcmu_find_mem_index(vma);
 726         if (mi < 0)
 727                 return VM_FAULT_SIGBUS;
 728
 729         /*
 730          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 731          * to use mem[N].
 732          */
 733         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 734
 735         addr = (void *)(unsigned long)info->mem[mi].addr + offset;
 736         if (info->mem[mi].memtype == UIO_MEM_LOGICAL)
 737                 page = virt_to_page(addr);
 738         else
 739                 page = vmalloc_to_page(addr);
 740         get_page(page);
 741         vmf->page = page;
 742         return 0;
 743 }
 744
 745 static const struct vm_operations_struct tcmu_vm_ops = {
 746         .fault = tcmu_vma_fault,
 747 };
 748
 749 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
 750 {
 751         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 752
 753         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 754         vma->vm_ops = &tcmu_vm_ops;
 755
 756         vma->vm_private_data = udev;
 757
 758         /* Ensure the mmap is exactly the right size */
 759         if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
 760                 return -EINVAL;
 761
 762         return 0;
 763 }
 764
 765 static int tcmu_open(struct uio_info *info, struct inode *inode)
 766 {
 767         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 768
 769         /* O_EXCL not supported for char devs, so fake it? */
 770         if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
 771                 return -EBUSY;
 772
 773         pr_debug("open\n");
 774
 775         return 0;
 776 }
 777
 778 static int tcmu_release(struct uio_info *info, struct inode *inode)
 779 {
 780         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 781
 782         clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
 783
 784         pr_debug("close\n");
 785
 786         return 0;
 787 }
 788
 789 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor)
 790 {
 791         struct sk_buff *skb;
 792         void *msg_header;
 793         int ret = -ENOMEM;
 794
 795         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 796         if (!skb)
 797                 return ret;
 798
 799         msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
 800         if (!msg_header)
 801                 goto free_skb;
 802
 803         ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name);
 804         if (ret < 0)
 805                 goto free_skb;
 806
 807         ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor);
 808         if (ret < 0)
 809                 goto free_skb;
 810
 811         genlmsg_end(skb, msg_header);
 812
 813         ret = genlmsg_multicast(&tcmu_genl_family, skb, 0,
 814                                 TCMU_MCGRP_CONFIG, GFP_KERNEL);
 815
 816         /* We don't care if no one is listening */
 817         if (ret == -ESRCH)
 818                 ret = 0;
 819
 820         return ret;
 821 free_skb:
 822         nlmsg_free(skb);
 823         return ret;
 824 }
 825
 826 static int tcmu_configure_device(struct se_device *dev)
 827 {
 828         struct tcmu_dev *udev = TCMU_DEV(dev);
 829         struct tcmu_hba *hba = udev->hba->hba_ptr;
 830         struct uio_info *info;
 831         struct tcmu_mailbox *mb;
 832         size_t size;
 833         size_t used;
 834         int ret = 0;
 835         char *str;
 836
 837         info = &udev->uio_info;
 838
 839         size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
 840                         udev->dev_config);
 841         size += 1; /* for \0 */
 842         str = kmalloc(size, GFP_KERNEL);
 843         if (!str)
 844                 return -ENOMEM;
 845
 846         used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
 847
 848         if (udev->dev_config[0])
 849                 snprintf(str + used, size - used, "/%s", udev->dev_config);
 850
 851         info->name = str;
 852
 853         udev->mb_addr = vzalloc(TCMU_RING_SIZE);
 854         if (!udev->mb_addr) {
 855                 ret = -ENOMEM;
 856                 goto err_vzalloc;
 857         }
 858
 859         /* mailbox fits in first part of CMDR space */
 860         udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
 861         udev->data_off = CMDR_SIZE;
 862         udev->data_size = TCMU_RING_SIZE - CMDR_SIZE;
 863
 864         mb = udev->mb_addr;
 865         mb->version = TCMU_MAILBOX_VERSION;
 866         mb->cmdr_off = CMDR_OFF;
 867         mb->cmdr_size = udev->cmdr_size;
 868
 869         WARN_ON(!PAGE_ALIGNED(udev->data_off));
 870         WARN_ON(udev->data_size % PAGE_SIZE);
 871
 872         info->version = xstr(TCMU_MAILBOX_VERSION);
 873
 874         info->mem[0].name = "tcm-user command & data buffer";
 875         info->mem[0].addr = (phys_addr_t) udev->mb_addr;
 876         info->mem[0].size = TCMU_RING_SIZE;
 877         info->mem[0].memtype = UIO_MEM_VIRTUAL;
 878
 879         info->irqcontrol = tcmu_irqcontrol;
 880         info->irq = UIO_IRQ_CUSTOM;
 881
 882         info->mmap = tcmu_mmap;
 883         info->open = tcmu_open;
 884         info->release = tcmu_release;
 885
 886         ret = uio_register_device(tcmu_root_device, info);
 887         if (ret)
 888                 goto err_register;
 889
 890         /* Other attributes can be configured in userspace */
 891         dev->dev_attrib.hw_block_size = 512;
 892         dev->dev_attrib.hw_max_sectors = 128;
 893         dev->dev_attrib.hw_queue_depth = 128;
 894
 895         ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
 896                                  udev->uio_info.uio_dev->minor);
 897         if (ret)
 898                 goto err_netlink;
 899
 900         return 0;
 901
 902 err_netlink:
 903         uio_unregister_device(&udev->uio_info);
 904 err_register:
 905         vfree(udev->mb_addr);
 906 err_vzalloc:
 907         kfree(info->name);
 908
 909         return ret;
 910 }
 911
 912 static int tcmu_check_pending_cmd(int id, void *p, void *data)
 913 {
 914         struct tcmu_cmd *cmd = p;
 915
 916         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
 917                 return 0;
 918         return -EINVAL;
 919 }
 920
 921 static void tcmu_free_device(struct se_device *dev)
 922 {
 923         struct tcmu_dev *udev = TCMU_DEV(dev);
 924         int i;
 925
 926         del_timer_sync(&udev->timeout);
 927
 928         vfree(udev->mb_addr);
 929
 930         /* Upper layer should drain all requests before calling this */
 931         spin_lock_irq(&udev->commands_lock);
 932         i = idr_for_each(&udev->commands, tcmu_check_pending_cmd, NULL);
 933         idr_destroy(&udev->commands);
 934         spin_unlock_irq(&udev->commands_lock);
 935         WARN_ON(i);
 936
 937         /* Device was configured */
 938         if (udev->uio_info.uio_dev) {
 939                 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
 940                                    udev->uio_info.uio_dev->minor);
 941
 942                 uio_unregister_device(&udev->uio_info);
 943                 kfree(udev->uio_info.name);
 944                 kfree(udev->name);
 945         }
 946
 947         kfree(udev);
 948 }
 949
 950 enum {
 951         Opt_dev_config, Opt_dev_size, Opt_err, Opt_pass_level,
 952 };
 953
 954 static match_table_t tokens = {
 955         {Opt_dev_config, "dev_config=%s"},
 956         {Opt_dev_size, "dev_size=%u"},
 957         {Opt_pass_level, "pass_level=%u"},
 958         {Opt_err, NULL}
 959 };
 960
 961 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
 962                 const char *page, ssize_t count)
 963 {
 964         struct tcmu_dev *udev = TCMU_DEV(dev);
 965         char *orig, *ptr, *opts, *arg_p;
 966         substring_t args[MAX_OPT_ARGS];
 967         int ret = 0, token;
 968         int arg;
 969
 970         opts = kstrdup(page, GFP_KERNEL);
 971         if (!opts)
 972                 return -ENOMEM;
 973
 974         orig = opts;
 975
 976         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 977                 if (!*ptr)
 978                         continue;
 979
 980                 token = match_token(ptr, tokens, args);
 981                 switch (token) {
 982                 case Opt_dev_config:
 983                         if (match_strlcpy(udev->dev_config, &args[0],
 984                                           TCMU_CONFIG_LEN) == 0) {
 985                                 ret = -EINVAL;
 986                                 break;
 987                         }
 988                         pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
 989                         break;
 990                 case Opt_dev_size:
 991                         arg_p = match_strdup(&args[0]);
 992                         if (!arg_p) {
 993                                 ret = -ENOMEM;
 994                                 break;
 995                         }
 996                         ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
 997                         kfree(arg_p);
 998                         if (ret < 0)
 999                                 pr_err("kstrtoul() failed for dev_size=\n");
1000                         break;
1001                 case Opt_pass_level:
1002                         match_int(args, &arg);
1003                         if (arg >= TCMU_PASS_INVALID) {
1004                                 pr_warn("TCMU: Invalid pass_level: %d\n", arg);
1005                                 break;
1006                         }
1007
1008                         pr_debug("TCMU: Setting pass_level to %d\n", arg);
1009                         udev->pass_level = arg;
1010                         break;
1011                 default:
1012                         break;
1013                 }
1014         }
1015
1016         kfree(orig);
1017         return (!ret) ? count : ret;
1018 }
1019
1020 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
1021 {
1022         struct tcmu_dev *udev = TCMU_DEV(dev);
1023         ssize_t bl = 0;
1024
1025         bl = sprintf(b + bl, "Config: %s ",
1026                      udev->dev_config[0] ? udev->dev_config : "NULL");
1027         bl += sprintf(b + bl, "Size: %zu PassLevel: %u\n",
1028                       udev->dev_size, udev->pass_level);
1029
1030         return bl;
1031 }
1032
1033 static sector_t tcmu_get_blocks(struct se_device *dev)
1034 {
1035         struct tcmu_dev *udev = TCMU_DEV(dev);
1036
1037         return div_u64(udev->dev_size - dev->dev_attrib.block_size,
1038                        dev->dev_attrib.block_size);
1039 }
1040
1041 static sense_reason_t
1042 tcmu_execute_rw(struct se_cmd *se_cmd, struct scatterlist *sgl, u32 sgl_nents,
1043                 enum dma_data_direction data_direction)
1044 {
1045         int ret;
1046
1047         ret = tcmu_queue_cmd(se_cmd);
1048
1049         if (ret != 0)
1050                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1051         else
1052                 return TCM_NO_SENSE;
1053 }
1054
1055 static sense_reason_t
1056 tcmu_pass_op(struct se_cmd *se_cmd)
1057 {
1058         int ret = tcmu_queue_cmd(se_cmd);
1059
1060         if (ret != 0)
1061                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1062         else
1063                 return TCM_NO_SENSE;
1064 }
1065
1066 static struct sbc_ops tcmu_sbc_ops = {
1067         .execute_rw = tcmu_execute_rw,
1068         .execute_sync_cache     = tcmu_pass_op,
1069         .execute_write_same     = tcmu_pass_op,
1070         .execute_write_same_unmap = tcmu_pass_op,
1071         .execute_unmap          = tcmu_pass_op,
1072 };
1073
1074 static sense_reason_t
1075 tcmu_parse_cdb(struct se_cmd *cmd)
1076 {
1077         unsigned char *cdb = cmd->t_task_cdb;
1078         struct tcmu_dev *udev = TCMU_DEV(cmd->se_dev);
1079         sense_reason_t ret;
1080
1081         switch (udev->pass_level) {
1082         case TCMU_PASS_ALL:
1083                 /* We're just like pscsi, then */
1084                 /*
1085                  * For REPORT LUNS we always need to emulate the response, for everything
1086                  * else, pass it up.
1087                  */
1088                 switch (cdb[0]) {
1089                 case REPORT_LUNS:
1090                         cmd->execute_cmd = spc_emulate_report_luns;
1091                         break;
1092                 case READ_6:
1093                 case READ_10:
1094                 case READ_12:
1095                 case READ_16:
1096                 case WRITE_6:
1097                 case WRITE_10:
1098                 case WRITE_12:
1099                 case WRITE_16:
1100                 case WRITE_VERIFY:
1101                         cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
1102                         /* FALLTHROUGH */
1103                 default:
1104                         cmd->execute_cmd = tcmu_pass_op;
1105                 }
1106                 ret = TCM_NO_SENSE;
1107                 break;
1108         case TCMU_PASS_IO:
1109                 ret = sbc_parse_cdb(cmd, &tcmu_sbc_ops);
1110                 break;
1111         default:
1112                 pr_err("Unknown tcm-user pass level %d\n", udev->pass_level);
1113                 ret = TCM_CHECK_CONDITION_ABORT_CMD;
1114         }
1115
1116         return ret;
1117 }
1118
1119 DEF_TB_DEFAULT_ATTRIBS(tcmu);
1120
1121 static struct configfs_attribute *tcmu_backend_dev_attrs[] = {
1122         &tcmu_dev_attrib_emulate_model_alias.attr,
1123         &tcmu_dev_attrib_emulate_dpo.attr,
1124         &tcmu_dev_attrib_emulate_fua_write.attr,
1125         &tcmu_dev_attrib_emulate_fua_read.attr,
1126         &tcmu_dev_attrib_emulate_write_cache.attr,
1127         &tcmu_dev_attrib_emulate_ua_intlck_ctrl.attr,
1128         &tcmu_dev_attrib_emulate_tas.attr,
1129         &tcmu_dev_attrib_emulate_tpu.attr,
1130         &tcmu_dev_attrib_emulate_tpws.attr,
1131         &tcmu_dev_attrib_emulate_caw.attr,
1132         &tcmu_dev_attrib_emulate_3pc.attr,
1133         &tcmu_dev_attrib_pi_prot_type.attr,
1134         &tcmu_dev_attrib_hw_pi_prot_type.attr,
1135         &tcmu_dev_attrib_pi_prot_format.attr,
1136         &tcmu_dev_attrib_enforce_pr_isids.attr,
1137         &tcmu_dev_attrib_is_nonrot.attr,
1138         &tcmu_dev_attrib_emulate_rest_reord.attr,
1139         &tcmu_dev_attrib_force_pr_aptpl.attr,
1140         &tcmu_dev_attrib_hw_block_size.attr,
1141         &tcmu_dev_attrib_block_size.attr,
1142         &tcmu_dev_attrib_hw_max_sectors.attr,
1143         &tcmu_dev_attrib_optimal_sectors.attr,
1144         &tcmu_dev_attrib_hw_queue_depth.attr,
1145         &tcmu_dev_attrib_queue_depth.attr,
1146         &tcmu_dev_attrib_max_unmap_lba_count.attr,
1147         &tcmu_dev_attrib_max_unmap_block_desc_count.attr,
1148         &tcmu_dev_attrib_unmap_granularity.attr,
1149         &tcmu_dev_attrib_unmap_granularity_alignment.attr,
1150         &tcmu_dev_attrib_max_write_same_len.attr,
1151         NULL,
1152 };
1153
1154 static struct se_subsystem_api tcmu_template = {
1155         .name                   = "user",
1156         .inquiry_prod           = "USER",
1157         .inquiry_rev            = TCMU_VERSION,
1158         .owner                  = THIS_MODULE,
1159         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
1160         .attach_hba             = tcmu_attach_hba,
1161         .detach_hba             = tcmu_detach_hba,
1162         .alloc_device           = tcmu_alloc_device,
1163         .configure_device       = tcmu_configure_device,
1164         .free_device            = tcmu_free_device,
1165         .parse_cdb              = tcmu_parse_cdb,
1166         .set_configfs_dev_params = tcmu_set_configfs_dev_params,
1167         .show_configfs_dev_params = tcmu_show_configfs_dev_params,
1168         .get_device_type        = sbc_get_device_type,
1169         .get_blocks             = tcmu_get_blocks,
1170 };
1171
1172 static int __init tcmu_module_init(void)
1173 {
1174         struct target_backend_cits *tbc = &tcmu_template.tb_cits;
1175         int ret;
1176
1177         BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
1178
1179         tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
1180                                 sizeof(struct tcmu_cmd),
1181                                 __alignof__(struct tcmu_cmd),
1182                                 0, NULL);
1183         if (!tcmu_cmd_cache)
1184                 return -ENOMEM;
1185
1186         tcmu_root_device = root_device_register("tcm_user");
1187         if (IS_ERR(tcmu_root_device)) {
1188                 ret = PTR_ERR(tcmu_root_device);
1189                 goto out_free_cache;
1190         }
1191
1192         ret = genl_register_family(&tcmu_genl_family);
1193         if (ret < 0) {
1194                 goto out_unreg_device;
1195         }
1196
1197         target_core_setup_sub_cits(&tcmu_template);
1198         tbc->tb_dev_attrib_cit.ct_attrs = tcmu_backend_dev_attrs;
1199
1200         ret = transport_subsystem_register(&tcmu_template);
1201         if (ret)
1202                 goto out_unreg_genl;
1203
1204         return 0;
1205
1206 out_unreg_genl:
1207         genl_unregister_family(&tcmu_genl_family);
1208 out_unreg_device:
1209         root_device_unregister(tcmu_root_device);
1210 out_free_cache:
1211         kmem_cache_destroy(tcmu_cmd_cache);
1212
1213         return ret;
1214 }
1215
1216 static void __exit tcmu_module_exit(void)
1217 {
1218         transport_subsystem_release(&tcmu_template);
1219         genl_unregister_family(&tcmu_genl_family);
1220         root_device_unregister(tcmu_root_device);
1221         kmem_cache_destroy(tcmu_cmd_cache);
1222 }
1223
1224 MODULE_DESCRIPTION("TCM USER subsystem plugin");
1225 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
1226 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
1227 MODULE_LICENSE("GPL");
1228
1229 module_init(tcmu_module_init);
1230 module_exit(tcmu_module_exit);