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          * transfering 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         scsi_host_put_command(scsi_tgt_cmd_to_host(cmd), cmd);
 189 }
 190
 191 static void init_scsi_tgt_cmd(struct request *rq, struct scsi_tgt_cmd *tcmd,
 192                               u64 itn_id, u64 tag)
 193 {
 194         struct scsi_tgt_queuedata *qdata = rq->q->queuedata;
 195         unsigned long flags;
 196         struct list_head *head;
 197
 198         tcmd->itn_id = itn_id;
 199         tcmd->tag = tag;
 200         tcmd->bio = NULL;
 201         INIT_WORK(&tcmd->work, scsi_tgt_cmd_destroy);
 202         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
 203         head = &qdata->cmd_hash[cmd_hashfn(tag)];
 204         list_add(&tcmd->hash_list, head);
 205         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 206 }
 207
 208 /*
 209  * scsi_tgt_alloc_queue - setup queue used for message passing
 210  * shost: scsi host
 211  *
 212  * This should be called by the LLD after host allocation.
 213  * And will be released when the host is released.
 214  */
 215 int scsi_tgt_alloc_queue(struct Scsi_Host *shost)
 216 {
 217         struct scsi_tgt_queuedata *queuedata;
 218         struct request_queue *q;
 219         int err, i;
 220
 221         /*
 222          * Do we need to send a netlink event or should uspace
 223          * just respond to the hotplug event?
 224          */
 225         q = __scsi_alloc_queue(shost, NULL);
 226         if (!q)
 227                 return -ENOMEM;
 228
 229         queuedata = kzalloc(sizeof(*queuedata), GFP_KERNEL);
 230         if (!queuedata) {
 231                 err = -ENOMEM;
 232                 goto cleanup_queue;
 233         }
 234         queuedata->shost = shost;
 235         q->queuedata = queuedata;
 236
 237         /*
 238          * this is a silly hack. We should probably just queue as many
 239          * command as is recvd to userspace. uspace can then make
 240          * sure we do not overload the HBA
 241          */
 242         q->nr_requests = shost->can_queue;
 243         /*
 244          * We currently only support software LLDs so this does
 245          * not matter for now. Do we need this for the cards we support?
 246          * If so we should make it a host template value.
 247          */
 248         blk_queue_dma_alignment(q, 0);
 249         shost->uspace_req_q = q;
 250
 251         for (i = 0; i < ARRAY_SIZE(queuedata->cmd_hash); i++)
 252                 INIT_LIST_HEAD(&queuedata->cmd_hash[i]);
 253         spin_lock_init(&queuedata->cmd_hash_lock);
 254
 255         return 0;
 256
 257 cleanup_queue:
 258         blk_cleanup_queue(q);
 259         return err;
 260 }
 261 EXPORT_SYMBOL_GPL(scsi_tgt_alloc_queue);
 262
 263 void scsi_tgt_free_queue(struct Scsi_Host *shost)
 264 {
 265         int i;
 266         unsigned long flags;
 267         struct request_queue *q = shost->uspace_req_q;
 268         struct scsi_cmnd *cmd;
 269         struct scsi_tgt_queuedata *qdata = q->queuedata;
 270         struct scsi_tgt_cmd *tcmd, *n;
 271         LIST_HEAD(cmds);
 272
 273         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
 274
 275         for (i = 0; i < ARRAY_SIZE(qdata->cmd_hash); i++) {
 276                 list_for_each_entry_safe(tcmd, n, &qdata->cmd_hash[i],
 277                                          hash_list) {
 278                         list_del(&tcmd->hash_list);
 279                         list_add(&tcmd->hash_list, &cmds);
 280                 }
 281         }
 282
 283         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 284
 285         while (!list_empty(&cmds)) {
 286                 tcmd = list_entry(cmds.next, struct scsi_tgt_cmd, hash_list);
 287                 list_del(&tcmd->hash_list);
 288                 cmd = tcmd->rq->special;
 289
 290                 shost->hostt->eh_abort_handler(cmd);
 291                 scsi_tgt_cmd_destroy(&tcmd->work);
 292         }
 293 }
 294 EXPORT_SYMBOL_GPL(scsi_tgt_free_queue);
 295
 296 struct Scsi_Host *scsi_tgt_cmd_to_host(struct scsi_cmnd *cmd)
 297 {
 298         struct scsi_tgt_queuedata *queue = cmd->request->q->queuedata;
 299         return queue->shost;
 300 }
 301 EXPORT_SYMBOL_GPL(scsi_tgt_cmd_to_host);
 302
 303 /*
 304  * scsi_tgt_queue_command - queue command for userspace processing
 305  * @cmd:        scsi command
 306  * @scsilun:    scsi lun
 307  * @tag:        unique value to identify this command for tmf
 308  */
 309 int scsi_tgt_queue_command(struct scsi_cmnd *cmd, u64 itn_id,
 310                            struct scsi_lun *scsilun, u64 tag)
 311 {
 312         struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;
 313         int err;
 314
 315         init_scsi_tgt_cmd(cmd->request, tcmd, itn_id, tag);
 316         err = scsi_tgt_uspace_send_cmd(cmd, itn_id, scsilun, tag);
 317         if (err)
 318                 cmd_hashlist_del(cmd);
 319
 320         return err;
 321 }
 322 EXPORT_SYMBOL_GPL(scsi_tgt_queue_command);
 323
 324 /*
 325  * This is run from a interrupt handler normally and the unmap
 326  * needs process context so we must queue
 327  */
 328 static void scsi_tgt_cmd_done(struct scsi_cmnd *cmd)
 329 {
 330         struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;
 331
 332         dprintk("cmd %p %u\n", cmd, rq_data_dir(cmd->request));
 333
 334         scsi_tgt_uspace_send_status(cmd, tcmd->itn_id, tcmd->tag);
 335
 336         scsi_release_buffers(cmd);
 337
 338         queue_work(scsi_tgtd, &tcmd->work);
 339 }
 340
 341 static int scsi_tgt_transfer_response(struct scsi_cmnd *cmd)
 342 {
 343         struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
 344         int err;
 345
 346         dprintk("cmd %p %u\n", cmd, rq_data_dir(cmd->request));
 347
 348         err = shost->hostt->transfer_response(cmd, scsi_tgt_cmd_done);
 349         switch (err) {
 350         case SCSI_MLQUEUE_HOST_BUSY:
 351         case SCSI_MLQUEUE_DEVICE_BUSY:
 352                 return -EAGAIN;
 353         }
 354         return 0;
 355 }
 356
 357 /* TODO: test this crap and replace bio_map_user with new interface maybe */
 358 static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd,
 359                                unsigned long uaddr, unsigned int len, int rw)
 360 {
 361         struct request_queue *q = cmd->request->q;
 362         struct request *rq = cmd->request;
 363         int err;
 364
 365         dprintk("%lx %u\n", uaddr, len);
 366         err = blk_rq_map_user(q, rq, NULL, (void *)uaddr, len, GFP_KERNEL);
 367         if (err) {
 368                 /*
 369                  * TODO: need to fixup sg_tablesize, max_segment_size,
 370                  * max_sectors, etc for modern HW and software drivers
 371                  * where this value is bogus.
 372                  *
 373                  * TODO2: we can alloc a reserve buffer of max size
 374                  * we can handle and do the slow copy path for really large
 375                  * IO.
 376                  */
 377                 eprintk("Could not handle request of size %u.\n", len);
 378                 return err;
 379         }
 380
 381         tcmd->bio = rq->bio;
 382         err = scsi_init_io(cmd, GFP_KERNEL);
 383         if (err) {
 384                 scsi_release_buffers(cmd);
 385                 goto unmap_rq;
 386         }
 387         /*
 388          * we use REQ_TYPE_BLOCK_PC so scsi_init_io doesn't set the
 389          * length for us.
 390          */
 391         cmd->sdb.length = blk_rq_bytes(rq);
 392
 393         return 0;
 394
 395 unmap_rq:
 396         scsi_unmap_user_pages(tcmd);
 397         return err;
 398 }
 399
 400 static int scsi_tgt_copy_sense(struct scsi_cmnd *cmd, unsigned long uaddr,
 401                                 unsigned len)
 402 {
 403         char __user *p = (char __user *) uaddr;
 404
 405         if (copy_from_user(cmd->sense_buffer, p,
 406                            min_t(unsigned, SCSI_SENSE_BUFFERSIZE, len))) {
 407                 printk(KERN_ERR "Could not copy the sense buffer\n");
 408                 return -EIO;
 409         }
 410         return 0;
 411 }
 412
 413 static int scsi_tgt_abort_cmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 414 {
 415         struct scsi_tgt_cmd *tcmd;
 416         int err;
 417
 418         err = shost->hostt->eh_abort_handler(cmd);
 419         if (err)
 420                 eprintk("fail to abort %p\n", cmd);
 421
 422         tcmd = cmd->request->end_io_data;
 423         scsi_tgt_cmd_destroy(&tcmd->work);
 424         return err;
 425 }
 426
 427 static struct request *tgt_cmd_hash_lookup(struct request_queue *q, u64 tag)
 428 {
 429         struct scsi_tgt_queuedata *qdata = q->queuedata;
 430         struct request *rq = NULL;
 431         struct list_head *head;
 432         struct scsi_tgt_cmd *tcmd;
 433         unsigned long flags;
 434
 435         head = &qdata->cmd_hash[cmd_hashfn(tag)];
 436         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
 437         list_for_each_entry(tcmd, head, hash_list) {
 438                 if (tcmd->tag == tag) {
 439                         rq = tcmd->rq;
 440                         list_del(&tcmd->hash_list);
 441                         break;
 442                 }
 443         }
 444         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 445
 446         return rq;
 447 }
 448
 449 int scsi_tgt_kspace_exec(int host_no, u64 itn_id, int result, u64 tag,
 450                          unsigned long uaddr, u32 len, unsigned long sense_uaddr,
 451                          u32 sense_len, u8 rw)
 452 {
 453         struct Scsi_Host *shost;
 454         struct scsi_cmnd *cmd;
 455         struct request *rq;
 456         struct scsi_tgt_cmd *tcmd;
 457         int err = 0;
 458
 459         dprintk("%d %llu %d %u %lx %u\n", host_no, (unsigned long long) tag,
 460                 result, len, uaddr, rw);
 461
 462         /* TODO: replace with a O(1) alg */
 463         shost = scsi_host_lookup(host_no);
 464         if (!shost) {
 465                 printk(KERN_ERR "Could not find host no %d\n", host_no);
 466                 return -EINVAL;
 467         }
 468
 469         if (!shost->uspace_req_q) {
 470                 printk(KERN_ERR "Not target scsi host %d\n", host_no);
 471                 goto done;
 472         }
 473
 474         rq = tgt_cmd_hash_lookup(shost->uspace_req_q, tag);
 475         if (!rq) {
 476                 printk(KERN_ERR "Could not find tag %llu\n",
 477                        (unsigned long long) tag);
 478                 err = -EINVAL;
 479                 goto done;
 480         }
 481         cmd = rq->special;
 482
 483         dprintk("cmd %p scb %x result %d len %d bufflen %u %u %x\n",
 484                 cmd, cmd->cmnd[0], result, len, scsi_bufflen(cmd),
 485                 rq_data_dir(rq), cmd->cmnd[0]);
 486
 487         if (result == TASK_ABORTED) {
 488                 scsi_tgt_abort_cmd(shost, cmd);
 489                 goto done;
 490         }
 491         /*
 492          * store the userspace values here, the working values are
 493          * in the request_* values
 494          */
 495         tcmd = cmd->request->end_io_data;
 496         cmd->result = result;
 497
 498         if (cmd->result == SAM_STAT_CHECK_CONDITION)
 499                 scsi_tgt_copy_sense(cmd, sense_uaddr, sense_len);
 500
 501         if (len) {
 502                 err = scsi_map_user_pages(rq->end_io_data, cmd, uaddr, len, rw);
 503                 if (err) {
 504                         /*
 505                          * user-space daemon bugs or OOM
 506                          * TODO: we can do better for OOM.
 507                          */
 508                         struct scsi_tgt_queuedata *qdata;
 509                         struct list_head *head;
 510                         unsigned long flags;
 511
 512                         eprintk("cmd %p ret %d uaddr %lx len %d rw %d\n",
 513                                 cmd, err, uaddr, len, rw);
 514
 515                         qdata = shost->uspace_req_q->queuedata;
 516                         head = &qdata->cmd_hash[cmd_hashfn(tcmd->tag)];
 517
 518                         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
 519                         list_add(&tcmd->hash_list, head);
 520                         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 521
 522                         goto done;
 523                 }
 524         }
 525         err = scsi_tgt_transfer_response(cmd);
 526 done:
 527         scsi_host_put(shost);
 528         return err;
 529 }
 530
 531 int scsi_tgt_tsk_mgmt_request(struct Scsi_Host *shost, u64 itn_id,
 532                               int function, u64 tag, struct scsi_lun *scsilun,
 533                               void *data)
 534 {
 535         int err;
 536
 537         /* TODO: need to retry if this fails. */
 538         err = scsi_tgt_uspace_send_tsk_mgmt(shost->host_no, itn_id,
 539                                             function, tag, scsilun, data);
 540         if (err < 0)
 541                 eprintk("The task management request lost!\n");
 542         return err;
 543 }
 544 EXPORT_SYMBOL_GPL(scsi_tgt_tsk_mgmt_request);
 545
 546 int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 itn_id, u64 mid, int result)
 547 {
 548         struct Scsi_Host *shost;
 549         int err = -EINVAL;
 550
 551         dprintk("%d %d %llx\n", host_no, result, (unsigned long long) mid);
 552
 553         shost = scsi_host_lookup(host_no);
 554         if (!shost) {
 555                 printk(KERN_ERR "Could not find host no %d\n", host_no);
 556                 return err;
 557         }
 558
 559         if (!shost->uspace_req_q) {
 560                 printk(KERN_ERR "Not target scsi host %d\n", host_no);
 561                 goto done;
 562         }
 563
 564         err = shost->transportt->tsk_mgmt_response(shost, itn_id, mid, result);
 565 done:
 566         scsi_host_put(shost);
 567         return err;
 568 }
 569
 570 int scsi_tgt_it_nexus_create(struct Scsi_Host *shost, u64 itn_id,
 571                              char *initiator)
 572 {
 573         int err;
 574
 575         /* TODO: need to retry if this fails. */
 576         err = scsi_tgt_uspace_send_it_nexus_request(shost->host_no, itn_id, 0,
 577                                                     initiator);
 578         if (err < 0)
 579                 eprintk("The i_t_neuxs request lost, %d %llx!\n",
 580                         shost->host_no, (unsigned long long)itn_id);
 581         return err;
 582 }
 583 EXPORT_SYMBOL_GPL(scsi_tgt_it_nexus_create);
 584
 585 int scsi_tgt_it_nexus_destroy(struct Scsi_Host *shost, u64 itn_id)
 586 {
 587         int err;
 588
 589         /* TODO: need to retry if this fails. */
 590         err = scsi_tgt_uspace_send_it_nexus_request(shost->host_no,
 591                                                     itn_id, 1, NULL);
 592         if (err < 0)
 593                 eprintk("The i_t_neuxs request lost, %d %llx!\n",
 594                         shost->host_no, (unsigned long long)itn_id);
 595         return err;
 596 }
 597 EXPORT_SYMBOL_GPL(scsi_tgt_it_nexus_destroy);
 598
 599 int scsi_tgt_kspace_it_nexus_rsp(int host_no, u64 itn_id, int result)
 600 {
 601         struct Scsi_Host *shost;
 602         int err = -EINVAL;
 603
 604         dprintk("%d %d%llx\n", host_no, result, (unsigned long long)itn_id);
 605
 606         shost = scsi_host_lookup(host_no);
 607         if (!shost) {
 608                 printk(KERN_ERR "Could not find host no %d\n", host_no);
 609                 return err;
 610         }
 611
 612         if (!shost->uspace_req_q) {
 613                 printk(KERN_ERR "Not target scsi host %d\n", host_no);
 614                 goto done;
 615         }
 616
 617         err = shost->transportt->it_nexus_response(shost, itn_id, result);
 618 done:
 619         scsi_host_put(shost);
 620         return err;
 621 }
 622
 623 static int __init scsi_tgt_init(void)
 624 {
 625         int err;
 626
 627         scsi_tgt_cmd_cache =  KMEM_CACHE(scsi_tgt_cmd, 0);
 628         if (!scsi_tgt_cmd_cache)
 629                 return -ENOMEM;
 630
 631         scsi_tgtd = create_workqueue("scsi_tgtd");
 632         if (!scsi_tgtd) {
 633                 err = -ENOMEM;
 634                 goto free_kmemcache;
 635         }
 636
 637         err = scsi_tgt_if_init();
 638         if (err)
 639                 goto destroy_wq;
 640
 641         return 0;
 642
 643 destroy_wq:
 644         destroy_workqueue(scsi_tgtd);
 645 free_kmemcache:
 646         kmem_cache_destroy(scsi_tgt_cmd_cache);
 647         return err;
 648 }
 649
 650 static void __exit scsi_tgt_exit(void)
 651 {
 652         destroy_workqueue(scsi_tgtd);
 653         scsi_tgt_if_exit();
 654         kmem_cache_destroy(scsi_tgt_cmd_cache);
 655 }
 656
 657 module_init(scsi_tgt_init);
 658 module_exit(scsi_tgt_exit);
 659
 660 MODULE_DESCRIPTION("SCSI target core");
 661 MODULE_LICENSE("GPL");