drivers/scsi/scsi_tgt_lib.c

   1 /*
   2  * SCSI target lib functions
   3  *
   4  * Copyright (C) 2005 Mike Christie <michaelc@cs.wisc.edu>
   5  * Copyright (C) 2005 FUJITA Tomonori <tomof@acm.org>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  20  * 02110-1301 USA
  21  */
  22 #include <linux/blkdev.h>
  23 #include <linux/hash.h>
  24 #include <linux/module.h>
  25 #include <linux/pagemap.h>
  26 #include <linux/slab.h>
  27 #include <scsi/scsi.h>
  28 #include <scsi/scsi_cmnd.h>
  29 #include <scsi/scsi_device.h>
  30 #include <scsi/scsi_host.h>
  31 #include <scsi/scsi_transport.h>
  32 #include <scsi/scsi_tgt.h>
  33
  34 #include "scsi_tgt_priv.h"
  35
  36 static struct workqueue_struct *scsi_tgtd;
  37 static struct kmem_cache *scsi_tgt_cmd_cache;
  38
  39 /*
  40  * TODO: this struct will be killed when the block layer supports large bios
  41  * and James's work struct code is in
  42  */
  43 struct scsi_tgt_cmd {
  44         /* TODO replace work with James b's code */
  45         struct work_struct work;
  46         /* TODO fix limits of some drivers */
  47         struct bio *bio;
  48
  49         struct list_head hash_list;
  50         struct request *rq;
  51         u64 itn_id;
  52         u64 tag;
  53 };
  54
  55 #define TGT_HASH_ORDER  4
  56 #define cmd_hashfn(tag) hash_long((unsigned long) (tag), TGT_HASH_ORDER)
  57
  58 struct scsi_tgt_queuedata {
  59         struct Scsi_Host *shost;
  60         struct list_head cmd_hash[1 << TGT_HASH_ORDER];
  61         spinlock_t cmd_hash_lock;
  62 };
  63
  64 /*
  65  * Function:    scsi_host_get_command()
  66  *
  67  * Purpose:     Allocate and setup a scsi command block and blk request
  68  *
  69  * Arguments:   shost   - scsi host
  70  *              data_dir - dma data dir
  71  *              gfp_mask- allocator flags
  72  *
  73  * Returns:     The allocated scsi command structure.
  74  *
  75  * This should be called by target LLDs to get a command.
  76  */
  77 struct scsi_cmnd *scsi_host_get_command(struct Scsi_Host *shost,
  78                                         enum dma_data_direction data_dir,
  79                                         gfp_t gfp_mask)
  80 {
  81         int write = (data_dir == DMA_TO_DEVICE);
  82         struct request *rq;
  83         struct scsi_cmnd *cmd;
  84         struct scsi_tgt_cmd *tcmd;
  85
  86         /* Bail if we can't get a reference to the device */
  87         if (!get_device(&shost->shost_gendev))
  88                 return NULL;
  89
  90         tcmd = kmem_cache_alloc(scsi_tgt_cmd_cache, GFP_ATOMIC);
  91         if (!tcmd)
  92                 goto put_dev;
  93
  94         /*
  95          * The blk helpers are used to the READ/WRITE requests
  96          * transferring data from a initiator point of view. Since
  97          * we are in target mode we want the opposite.
  98          */
  99         rq = blk_get_request(shost->uspace_req_q, !write, gfp_mask);
 100         if (!rq)
 101                 goto free_tcmd;
 102
 103         cmd = __scsi_get_command(shost, gfp_mask);
 104         if (!cmd)
 105                 goto release_rq;
 106
 107         cmd->sc_data_direction = data_dir;
 108         cmd->jiffies_at_alloc = jiffies;
 109         cmd->request = rq;
 110
 111         cmd->cmnd = rq->cmd;
 112
 113         rq->special = cmd;
 114         rq->cmd_type = REQ_TYPE_SPECIAL;
 115         rq->cmd_flags |= REQ_TYPE_BLOCK_PC;
 116         rq->end_io_data = tcmd;
 117
 118         tcmd->rq = rq;
 119
 120         return cmd;
 121
 122 release_rq:
 123         blk_put_request(rq);
 124 free_tcmd:
 125         kmem_cache_free(scsi_tgt_cmd_cache, tcmd);
 126 put_dev:
 127         put_device(&shost->shost_gendev);
 128         return NULL;
 129
 130 }
 131 EXPORT_SYMBOL_GPL(scsi_host_get_command);
 132
 133 /*
 134  * Function:    scsi_host_put_command()
 135  *
 136  * Purpose:     Free a scsi command block
 137  *
 138  * Arguments:   shost   - scsi host
 139  *              cmd     - command block to free
 140  *
 141  * Returns:     Nothing.
 142  *
 143  * Notes:       The command must not belong to any lists.
 144  */
 145 void scsi_host_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 146 {
 147         struct request_queue *q = shost->uspace_req_q;
 148         struct request *rq = cmd->request;
 149         struct scsi_tgt_cmd *tcmd = rq->end_io_data;
 150         unsigned long flags;
 151
 152         kmem_cache_free(scsi_tgt_cmd_cache, tcmd);
 153
 154         spin_lock_irqsave(q->queue_lock, flags);
 155         __blk_put_request(q, rq);
 156         spin_unlock_irqrestore(q->queue_lock, flags);
 157
 158         __scsi_put_command(shost, cmd, &shost->shost_gendev);
 159 }
 160 EXPORT_SYMBOL_GPL(scsi_host_put_command);
 161
 162 static void cmd_hashlist_del(struct scsi_cmnd *cmd)
 163 {
 164         struct request_queue *q = cmd->request->q;
 165         struct scsi_tgt_queuedata *qdata = q->queuedata;
 166         unsigned long flags;
 167         struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;
 168
 169         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
 170         list_del(&tcmd->hash_list);
 171         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 172 }
 173
 174 static void scsi_unmap_user_pages(struct scsi_tgt_cmd *tcmd)
 175 {
 176         blk_rq_unmap_user(tcmd->bio);
 177 }
 178
 179 static void scsi_tgt_cmd_destroy(struct work_struct *work)
 180 {
 181         struct scsi_tgt_cmd *tcmd =
 182                 container_of(work, struct scsi_tgt_cmd, work);
 183         struct scsi_cmnd *cmd = tcmd->rq->special;
 184
 185         dprintk("cmd %p %d %u\n", cmd, cmd->sc_data_direction,
 186                 rq_data_dir(cmd->request));
 187         scsi_unmap_user_pages(tcmd);
 188         tcmd->rq->bio = NULL;
 189         scsi_host_put_command(scsi_tgt_cmd_to_host(cmd), cmd);
 190 }
 191
 192 static void init_scsi_tgt_cmd(struct request *rq, struct scsi_tgt_cmd *tcmd,
 193                               u64 itn_id, u64 tag)
 194 {
 195         struct scsi_tgt_queuedata *qdata = rq->q->queuedata;
 196         unsigned long flags;
 197         struct list_head *head;
 198
 199         tcmd->itn_id = itn_id;
 200         tcmd->tag = tag;
 201         tcmd->bio = NULL;
 202         INIT_WORK(&tcmd->work, scsi_tgt_cmd_destroy);
 203         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
 204         head = &qdata->cmd_hash[cmd_hashfn(tag)];
 205         list_add(&tcmd->hash_list, head);
 206         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 207 }
 208
 209 /*
 210  * scsi_tgt_alloc_queue - setup queue used for message passing
 211  * shost: scsi host
 212  *
 213  * This should be called by the LLD after host allocation.
 214  * And will be released when the host is released.
 215  */
 216 int scsi_tgt_alloc_queue(struct Scsi_Host *shost)
 217 {
 218         struct scsi_tgt_queuedata *queuedata;
 219         struct request_queue *q;
 220         int err, i;
 221
 222         /*
 223          * Do we need to send a netlink event or should uspace
 224          * just respond to the hotplug event?
 225          */
 226         q = __scsi_alloc_queue(shost, NULL);
 227         if (!q)
 228                 return -ENOMEM;
 229
 230         queuedata = kzalloc(sizeof(*queuedata), GFP_KERNEL);
 231         if (!queuedata) {
 232                 err = -ENOMEM;
 233                 goto cleanup_queue;
 234         }
 235         queuedata->shost = shost;
 236         q->queuedata = queuedata;
 237
 238         /*
 239          * this is a silly hack. We should probably just queue as many
 240          * command as is recvd to userspace. uspace can then make
 241          * sure we do not overload the HBA
 242          */
 243         q->nr_requests = shost->can_queue;
 244         /*
 245          * We currently only support software LLDs so this does
 246          * not matter for now. Do we need this for the cards we support?
 247          * If so we should make it a host template value.
 248          */
 249         blk_queue_dma_alignment(q, 0);
 250         shost->uspace_req_q = q;
 251
 252         for (i = 0; i < ARRAY_SIZE(queuedata->cmd_hash); i++)
 253                 INIT_LIST_HEAD(&queuedata->cmd_hash[i]);
 254         spin_lock_init(&queuedata->cmd_hash_lock);
 255
 256         return 0;
 257
 258 cleanup_queue:
 259         blk_cleanup_queue(q);
 260         return err;
 261 }
 262 EXPORT_SYMBOL_GPL(scsi_tgt_alloc_queue);
 263
 264 void scsi_tgt_free_queue(struct Scsi_Host *shost)
 265 {
 266         int i;
 267         unsigned long flags;
 268         struct request_queue *q = shost->uspace_req_q;
 269         struct scsi_cmnd *cmd;
 270         struct scsi_tgt_queuedata *qdata = q->queuedata;
 271         struct scsi_tgt_cmd *tcmd, *n;
 272         LIST_HEAD(cmds);
 273
 274         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
 275
 276         for (i = 0; i < ARRAY_SIZE(qdata->cmd_hash); i++) {
 277                 list_for_each_entry_safe(tcmd, n, &qdata->cmd_hash[i],
 278                                          hash_list) {
 279                         list_del(&tcmd->hash_list);
 280                         list_add(&tcmd->hash_list, &cmds);
 281                 }
 282         }
 283
 284         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 285
 286         while (!list_empty(&cmds)) {
 287                 tcmd = list_entry(cmds.next, struct scsi_tgt_cmd, hash_list);
 288                 list_del(&tcmd->hash_list);
 289                 cmd = tcmd->rq->special;
 290
 291                 shost->hostt->eh_abort_handler(cmd);
 292                 scsi_tgt_cmd_destroy(&tcmd->work);
 293         }
 294 }
 295 EXPORT_SYMBOL_GPL(scsi_tgt_free_queue);
 296
 297 struct Scsi_Host *scsi_tgt_cmd_to_host(struct scsi_cmnd *cmd)
 298 {
 299         struct scsi_tgt_queuedata *queue = cmd->request->q->queuedata;
 300         return queue->shost;
 301 }
 302 EXPORT_SYMBOL_GPL(scsi_tgt_cmd_to_host);
 303
 304 /*
 305  * scsi_tgt_queue_command - queue command for userspace processing
 306  * @cmd:        scsi command
 307  * @scsilun:    scsi lun
 308  * @tag:        unique value to identify this command for tmf
 309  */
 310 int scsi_tgt_queue_command(struct scsi_cmnd *cmd, u64 itn_id,
 311                            struct scsi_lun *scsilun, u64 tag)
 312 {
 313         struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;
 314         int err;
 315
 316         init_scsi_tgt_cmd(cmd->request, tcmd, itn_id, tag);
 317         err = scsi_tgt_uspace_send_cmd(cmd, itn_id, scsilun, tag);
 318         if (err)
 319                 cmd_hashlist_del(cmd);
 320
 321         return err;
 322 }
 323 EXPORT_SYMBOL_GPL(scsi_tgt_queue_command);
 324
 325 /*
 326  * This is run from a interrupt handler normally and the unmap
 327  * needs process context so we must queue
 328  */
 329 static void scsi_tgt_cmd_done(struct scsi_cmnd *cmd)
 330 {
 331         struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;
 332
 333         dprintk("cmd %p %u\n", cmd, rq_data_dir(cmd->request));
 334
 335         scsi_tgt_uspace_send_status(cmd, tcmd->itn_id, tcmd->tag);
 336
 337         scsi_release_buffers(cmd);
 338
 339         queue_work(scsi_tgtd, &tcmd->work);
 340 }
 341
 342 static int scsi_tgt_transfer_response(struct scsi_cmnd *cmd)
 343 {
 344         struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
 345         int err;
 346
 347         dprintk("cmd %p %u\n", cmd, rq_data_dir(cmd->request));
 348
 349         err = shost->hostt->transfer_response(cmd, scsi_tgt_cmd_done);
 350         switch (err) {
 351         case SCSI_MLQUEUE_HOST_BUSY:
 352         case SCSI_MLQUEUE_DEVICE_BUSY:
 353                 return -EAGAIN;
 354         }
 355         return 0;
 356 }
 357
 358 /* TODO: test this crap and replace bio_map_user with new interface maybe */
 359 static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd,
 360                                unsigned long uaddr, unsigned int len, int rw)
 361 {
 362         struct request_queue *q = cmd->request->q;
 363         struct request *rq = cmd->request;
 364         int err;
 365
 366         dprintk("%lx %u\n", uaddr, len);
 367         err = blk_rq_map_user(q, rq, NULL, (void *)uaddr, len, GFP_KERNEL);
 368         if (err) {
 369                 /*
 370                  * TODO: need to fixup sg_tablesize, max_segment_size,
 371                  * max_sectors, etc for modern HW and software drivers
 372                  * where this value is bogus.
 373                  *
 374                  * TODO2: we can alloc a reserve buffer of max size
 375                  * we can handle and do the slow copy path for really large
 376                  * IO.
 377                  */
 378                 eprintk("Could not handle request of size %u.\n", len);
 379                 return err;
 380         }
 381
 382         tcmd->bio = rq->bio;
 383         err = scsi_init_io(cmd, GFP_KERNEL);
 384         if (err) {
 385                 scsi_release_buffers(cmd);
 386                 goto unmap_rq;
 387         }
 388         /*
 389          * we use REQ_TYPE_BLOCK_PC so scsi_init_io doesn't set the
 390          * length for us.
 391          */
 392         cmd->sdb.length = blk_rq_bytes(rq);
 393
 394         return 0;
 395
 396 unmap_rq:
 397         scsi_unmap_user_pages(tcmd);
 398         return err;
 399 }
 400
 401 static int scsi_tgt_copy_sense(struct scsi_cmnd *cmd, unsigned long uaddr,
 402                                 unsigned len)
 403 {
 404         char __user *p = (char __user *) uaddr;
 405
 406         if (copy_from_user(cmd->sense_buffer, p,
 407                            min_t(unsigned, SCSI_SENSE_BUFFERSIZE, len))) {
 408                 printk(KERN_ERR "Could not copy the sense buffer\n");
 409                 return -EIO;
 410         }
 411         return 0;
 412 }
 413
 414 static int scsi_tgt_abort_cmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 415 {
 416         struct scsi_tgt_cmd *tcmd;
 417         int err;
 418
 419         err = shost->hostt->eh_abort_handler(cmd);
 420         if (err)
 421                 eprintk("fail to abort %p\n", cmd);
 422
 423         tcmd = cmd->request->end_io_data;
 424         scsi_tgt_cmd_destroy(&tcmd->work);
 425         return err;
 426 }
 427
 428 static struct request *tgt_cmd_hash_lookup(struct request_queue *q, u64 tag)
 429 {
 430         struct scsi_tgt_queuedata *qdata = q->queuedata;
 431         struct request *rq = NULL;
 432         struct list_head *head;
 433         struct scsi_tgt_cmd *tcmd;
 434         unsigned long flags;
 435
 436         head = &qdata->cmd_hash[cmd_hashfn(tag)];
 437         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
 438         list_for_each_entry(tcmd, head, hash_list) {
 439                 if (tcmd->tag == tag) {
 440                         rq = tcmd->rq;
 441                         list_del(&tcmd->hash_list);
 442                         break;
 443                 }
 444         }
 445         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 446
 447         return rq;
 448 }
 449
 450 int scsi_tgt_kspace_exec(int host_no, u64 itn_id, int result, u64 tag,
 451                          unsigned long uaddr, u32 len, unsigned long sense_uaddr,
 452                          u32 sense_len, u8 rw)
 453 {
 454         struct Scsi_Host *shost;
 455         struct scsi_cmnd *cmd;
 456         struct request *rq;
 457         struct scsi_tgt_cmd *tcmd;
 458         int err = 0;
 459
 460         dprintk("%d %llu %d %u %lx %u\n", host_no, (unsigned long long) tag,
 461                 result, len, uaddr, rw);
 462
 463         /* TODO: replace with a O(1) alg */
 464         shost = scsi_host_lookup(host_no);
 465         if (!shost) {
 466                 printk(KERN_ERR "Could not find host no %d\n", host_no);
 467                 return -EINVAL;
 468         }
 469
 470         if (!shost->uspace_req_q) {
 471                 printk(KERN_ERR "Not target scsi host %d\n", host_no);
 472                 goto done;
 473         }
 474
 475         rq = tgt_cmd_hash_lookup(shost->uspace_req_q, tag);
 476         if (!rq) {
 477                 printk(KERN_ERR "Could not find tag %llu\n",
 478                        (unsigned long long) tag);
 479                 err = -EINVAL;
 480                 goto done;
 481         }
 482         cmd = rq->special;
 483
 484         dprintk("cmd %p scb %x result %d len %d bufflen %u %u %x\n",
 485                 cmd, cmd->cmnd[0], result, len, scsi_bufflen(cmd),
 486                 rq_data_dir(rq), cmd->cmnd[0]);
 487
 488         if (result == TASK_ABORTED) {
 489                 scsi_tgt_abort_cmd(shost, cmd);
 490                 goto done;
 491         }
 492         /*
 493          * store the userspace values here, the working values are
 494          * in the request_* values
 495          */
 496         tcmd = cmd->request->end_io_data;
 497         cmd->result = result;
 498
 499         if (cmd->result == SAM_STAT_CHECK_CONDITION)
 500                 scsi_tgt_copy_sense(cmd, sense_uaddr, sense_len);
 501
 502         if (len) {
 503                 err = scsi_map_user_pages(rq->end_io_data, cmd, uaddr, len, rw);
 504                 if (err) {
 505                         /*
 506                          * user-space daemon bugs or OOM
 507                          * TODO: we can do better for OOM.
 508                          */
 509                         struct scsi_tgt_queuedata *qdata;
 510                         struct list_head *head;
 511                         unsigned long flags;
 512
 513                         eprintk("cmd %p ret %d uaddr %lx len %d rw %d\n",
 514                                 cmd, err, uaddr, len, rw);
 515
 516                         qdata = shost->uspace_req_q->queuedata;
 517                         head = &qdata->cmd_hash[cmd_hashfn(tcmd->tag)];
 518
 519                         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
 520                         list_add(&tcmd->hash_list, head);
 521                         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 522
 523                         goto done;
 524                 }
 525         }
 526         err = scsi_tgt_transfer_response(cmd);
 527 done:
 528         scsi_host_put(shost);
 529         return err;
 530 }
 531
 532 int scsi_tgt_tsk_mgmt_request(struct Scsi_Host *shost, u64 itn_id,
 533                               int function, u64 tag, struct scsi_lun *scsilun,
 534                               void *data)
 535 {
 536         int err;
 537
 538         /* TODO: need to retry if this fails. */
 539         err = scsi_tgt_uspace_send_tsk_mgmt(shost->host_no, itn_id,
 540                                             function, tag, scsilun, data);
 541         if (err < 0)
 542                 eprintk("The task management request lost!\n");
 543         return err;
 544 }
 545 EXPORT_SYMBOL_GPL(scsi_tgt_tsk_mgmt_request);
 546
 547 int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 itn_id, u64 mid, int result)
 548 {
 549         struct Scsi_Host *shost;
 550         int err = -EINVAL;
 551
 552         dprintk("%d %d %llx\n", host_no, result, (unsigned long long) mid);
 553
 554         shost = scsi_host_lookup(host_no);
 555         if (!shost) {
 556                 printk(KERN_ERR "Could not find host no %d\n", host_no);
 557                 return err;
 558         }
 559
 560         if (!shost->uspace_req_q) {
 561                 printk(KERN_ERR "Not target scsi host %d\n", host_no);
 562                 goto done;
 563         }
 564
 565         err = shost->transportt->tsk_mgmt_response(shost, itn_id, mid, result);
 566 done:
 567         scsi_host_put(shost);
 568         return err;
 569 }
 570
 571 int scsi_tgt_it_nexus_create(struct Scsi_Host *shost, u64 itn_id,
 572                              char *initiator)
 573 {
 574         int err;
 575
 576         /* TODO: need to retry if this fails. */
 577         err = scsi_tgt_uspace_send_it_nexus_request(shost->host_no, itn_id, 0,
 578                                                     initiator);
 579         if (err < 0)
 580                 eprintk("The i_t_neuxs request lost, %d %llx!\n",
 581                         shost->host_no, (unsigned long long)itn_id);
 582         return err;
 583 }
 584 EXPORT_SYMBOL_GPL(scsi_tgt_it_nexus_create);
 585
 586 int scsi_tgt_it_nexus_destroy(struct Scsi_Host *shost, u64 itn_id)
 587 {
 588         int err;
 589
 590         /* TODO: need to retry if this fails. */
 591         err = scsi_tgt_uspace_send_it_nexus_request(shost->host_no,
 592                                                     itn_id, 1, NULL);
 593         if (err < 0)
 594                 eprintk("The i_t_neuxs request lost, %d %llx!\n",
 595                         shost->host_no, (unsigned long long)itn_id);
 596         return err;
 597 }
 598 EXPORT_SYMBOL_GPL(scsi_tgt_it_nexus_destroy);
 599
 600 int scsi_tgt_kspace_it_nexus_rsp(int host_no, u64 itn_id, int result)
 601 {
 602         struct Scsi_Host *shost;
 603         int err = -EINVAL;
 604
 605         dprintk("%d %d%llx\n", host_no, result, (unsigned long long)itn_id);
 606
 607         shost = scsi_host_lookup(host_no);
 608         if (!shost) {
 609                 printk(KERN_ERR "Could not find host no %d\n", host_no);
 610                 return err;
 611         }
 612
 613         if (!shost->uspace_req_q) {
 614                 printk(KERN_ERR "Not target scsi host %d\n", host_no);
 615                 goto done;
 616         }
 617
 618         err = shost->transportt->it_nexus_response(shost, itn_id, result);
 619 done:
 620         scsi_host_put(shost);
 621         return err;
 622 }
 623
 624 static int __init scsi_tgt_init(void)
 625 {
 626         int err;
 627
 628         scsi_tgt_cmd_cache =  KMEM_CACHE(scsi_tgt_cmd, 0);
 629         if (!scsi_tgt_cmd_cache)
 630                 return -ENOMEM;
 631
 632         scsi_tgtd = alloc_workqueue("scsi_tgtd", 0, 1);
 633         if (!scsi_tgtd) {
 634                 err = -ENOMEM;
 635                 goto free_kmemcache;
 636         }
 637
 638         err = scsi_tgt_if_init();
 639         if (err)
 640                 goto destroy_wq;
 641
 642         return 0;
 643
 644 destroy_wq:
 645         destroy_workqueue(scsi_tgtd);
 646 free_kmemcache:
 647         kmem_cache_destroy(scsi_tgt_cmd_cache);
 648         return err;
 649 }
 650
 651 static void __exit scsi_tgt_exit(void)
 652 {
 653         destroy_workqueue(scsi_tgtd);
 654         scsi_tgt_if_exit();
 655         kmem_cache_destroy(scsi_tgt_cmd_cache);
 656 }
 657
 658 module_init(scsi_tgt_init);
 659 module_exit(scsi_tgt_exit);
 660
 661 MODULE_DESCRIPTION("SCSI target core");
 662 MODULE_LICENSE("GPL");