aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/scsi/scsi_tgt_lib.c
blob: 01e03f3f6ffa39ea7240dfe355ddd7edf5a5981c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
/*
 * SCSI target lib functions
 *
 * Copyright (C) 2005 Mike Christie <michaelc@cs.wisc.edu>
 * Copyright (C) 2005 FUJITA Tomonori <tomof@acm.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */
#include <linux/blkdev.h>
#include <linux/hash.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_tgt.h>

#include "scsi_tgt_priv.h"

static struct workqueue_struct *scsi_tgtd;
static struct kmem_cache *scsi_tgt_cmd_cache;

/*
 * TODO: this struct will be killed when the block layer supports large bios
 * and James's work struct code is in
 */
struct scsi_tgt_cmd {
	/* TODO replace work with James b's code */
	struct work_struct work;
	/* TODO fix limits of some drivers */
	struct bio *bio;

	struct list_head hash_list;
	struct request *rq;
	u64 itn_id;
	u64 tag;
};

#define TGT_HASH_ORDER	4
#define cmd_hashfn(tag)	hash_long((unsigned long) (tag), TGT_HASH_ORDER)

struct scsi_tgt_queuedata {
	struct Scsi_Host *shost;
	struct list_head cmd_hash[1 << TGT_HASH_ORDER];
	spinlock_t cmd_hash_lock;
};

/*
 * Function:	scsi_host_get_command()
 *
 * Purpose:	Allocate and setup a scsi command block and blk request
 *
 * Arguments:	shost	- scsi host
 *		data_dir - dma data dir
 *		gfp_mask- allocator flags
 *
 * Returns:	The allocated scsi command structure.
 *
 * This should be called by target LLDs to get a command.
 */
struct scsi_cmnd *scsi_host_get_command(struct Scsi_Host *shost,
					enum dma_data_direction data_dir,
					gfp_t gfp_mask)
{
	int write = (data_dir == DMA_TO_DEVICE);
	struct request *rq;
	struct scsi_cmnd *cmd;
	struct scsi_tgt_cmd *tcmd;

	/* Bail if we can't get a reference to the device */
	if (!get_device(&shost->shost_gendev))
		return NULL;

	tcmd = kmem_cache_alloc(scsi_tgt_cmd_cache, GFP_ATOMIC);
	if (!tcmd)
		goto put_dev;

	/*
	 * The blk helpers are used to the READ/WRITE requests
	 * transfering data from a initiator point of view. Since
	 * we are in target mode we want the opposite.
	 */
	rq = blk_get_request(shost->uspace_req_q, !write, gfp_mask);
	if (!rq)
		goto free_tcmd;

	cmd = __scsi_get_command(shost, gfp_mask);
	if (!cmd)
		goto release_rq;

	memset(cmd, 0, sizeof(*cmd));
	cmd->sc_data_direction = data_dir;
	cmd->jiffies_at_alloc = jiffies;
	cmd->request = rq;

	rq->special = cmd;
	rq->cmd_type = REQ_TYPE_SPECIAL;
	rq->cmd_flags |= REQ_TYPE_BLOCK_PC;
	rq->end_io_data = tcmd;

	tcmd->rq = rq;

	return cmd;

release_rq:
	blk_put_request(rq);
free_tcmd:
	kmem_cache_free(scsi_tgt_cmd_cache, tcmd);
put_dev:
	put_device(&shost->shost_gendev);
	return NULL;

}
EXPORT_SYMBOL_GPL(scsi_host_get_command);

/*
 * Function:	scsi_host_put_command()
 *
 * Purpose:	Free a scsi command block
 *
 * Arguments:	shost	- scsi host
 * 		cmd	- command block to free
 *
 * Returns:	Nothing.
 *
 * Notes:	The command must not belong to any lists.
 */
void scsi_host_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
{
	struct request_queue *q = shost->uspace_req_q;
	struct request *rq = cmd->request;
	struct scsi_tgt_cmd *tcmd = rq->end_io_data;
	unsigned long flags;

	kmem_cache_free(scsi_tgt_cmd_cache, tcmd);

	spin_lock_irqsave(q->queue_lock, flags);
	__blk_put_request(q, rq);
	spin_unlock_irqrestore(q->queue_lock, flags);

	__scsi_put_command(shost, cmd, &shost->shost_gendev);
}
EXPORT_SYMBOL_GPL(scsi_host_put_command);

static void cmd_hashlist_del(struct scsi_cmnd *cmd)
{
	struct request_queue *q = cmd->request->q;
	struct scsi_tgt_queuedata *qdata = q->queuedata;
	unsigned long flags;
	struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;

	spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
	list_del(&tcmd->hash_list);
	spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
}

static void scsi_unmap_user_pages(struct scsi_tgt_cmd *tcmd)
{
	blk_rq_unmap_user(tcmd->bio);
}

static void scsi_tgt_cmd_destroy(struct work_struct *work)
{
	struct scsi_tgt_cmd *tcmd =
		container_of(work, struct scsi_tgt_cmd, work);
	struct scsi_cmnd *cmd = tcmd->rq->special;

	dprintk("cmd %p %d %u\n", cmd, cmd->sc_data_direction,
		rq_data_dir(cmd->request));
	scsi_unmap_user_pages(tcmd);
	scsi_host_put_command(scsi_tgt_cmd_to_host(cmd), cmd);
}

static void init_scsi_tgt_cmd(struct request *rq, struct scsi_tgt_cmd *tcmd,
			      u64 itn_id, u64 tag)
{
	struct scsi_tgt_queuedata *qdata = rq->q->queuedata;
	unsigned long flags;
	struct list_head *head;

	tcmd->itn_id = itn_id;
	tcmd->tag = tag;
	tcmd->bio = NULL;
	INIT_WORK(&tcmd->work, scsi_tgt_cmd_destroy);
	spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
	head = &qdata->cmd_hash[cmd_hashfn(tag)];
	list_add(&tcmd->hash_list, head);
	spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
}

/*
 * scsi_tgt_alloc_queue - setup queue used for message passing
 * shost: scsi host
 *
 * This should be called by the LLD after host allocation.
 * And will be released when the host is released.
 */
int scsi_tgt_alloc_queue(struct Scsi_Host *shost)
{
	struct scsi_tgt_queuedata *queuedata;
	struct request_queue *q;
	int err, i;

	/*
	 * Do we need to send a netlink event or should uspace
	 * just respond to the hotplug event?
	 */
	q = __scsi_alloc_queue(shost, NULL);
	if (!q)
		return -ENOMEM;

	queuedata = kzalloc(sizeof(*queuedata), GFP_KERNEL);
	if (!queuedata) {
		err = -ENOMEM;
		goto cleanup_queue;
	}
	queuedata->shost = shost;
	q->queuedata = queuedata;

	/*
	 * this is a silly hack. We should probably just queue as many
	 * command as is recvd to userspace. uspace can then make
	 * sure we do not overload the HBA
	 */
	q->nr_requests = shost->can_queue;
	/*
	 * We currently only support software LLDs so this does
	 * not matter for now. Do we need this for the cards we support?
	 * If so we should make it a host template value.
	 */
	blk_queue_dma_alignment(q, 0);
	shost->uspace_req_q = q;

	for (i = 0; i < ARRAY_SIZE(queuedata->cmd_hash); i++)
		INIT_LIST_HEAD(&queuedata->cmd_hash[i]);
	spin_lock_init(&queuedata->cmd_hash_lock);

	return 0;

cleanup_queue:
	blk_cleanup_queue(q);
	return err;
}
EXPORT_SYMBOL_GPL(scsi_tgt_alloc_queue);

void scsi_tgt_free_queue(struct Scsi_Host *shost)
{
	int i;
	unsigned long flags;
	struct request_queue *q = shost->uspace_req_q;
	struct scsi_cmnd *cmd;
	struct scsi_tgt_queuedata *qdata = q->queuedata;
	struct scsi_tgt_cmd *tcmd, *n;
	LIST_HEAD(cmds);

	spin_lock_irqsave(&qdata->cmd_hash_lock, flags);

	for (i = 0; i < ARRAY_SIZE(qdata->cmd_hash); i++) {
		list_for_each_entry_safe(tcmd, n, &qdata->cmd_hash[i],
					 hash_list) {
			list_del(&tcmd->hash_list);
			list_add(&tcmd->hash_list, &cmds);
		}
	}

	spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);

	while (!list_empty(&cmds)) {
		tcmd = list_entry(cmds.next, struct scsi_tgt_cmd, hash_list);
		list_del(&tcmd->hash_list);
		cmd = tcmd->rq->special;

		shost->hostt->eh_abort_handler(cmd);
		scsi_tgt_cmd_destroy(&tcmd->work);
	}
}
EXPORT_SYMBOL_GPL(scsi_tgt_free_queue);

struct Scsi_Host *scsi_tgt_cmd_to_host(struct scsi_cmnd *cmd)
{
	struct scsi_tgt_queuedata *queue = cmd->request->q->queuedata;
	return queue->shost;
}
EXPORT_SYMBOL_GPL(scsi_tgt_cmd_to_host);

/*
 * scsi_tgt_queue_command - queue command for userspace processing
 * @cmd:	scsi command
 * @scsilun:	scsi lun
 * @tag:	unique value to identify this command for tmf
 */
int scsi_tgt_queue_command(struct scsi_cmnd *cmd, u64 itn_id,
			   struct scsi_lun *scsilun, u64 tag)
{
	struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;
	int err;

	init_scsi_tgt_cmd(cmd->request, tcmd, itn_id, tag);
	err = scsi_tgt_uspace_send_cmd(cmd, itn_id, scsilun, tag);
	if (err)
		cmd_hashlist_del(cmd);

	return err;
}
EXPORT_SYMBOL_GPL(scsi_tgt_queue_command);

/*
 * This is run from a interrpt handler normally and the unmap
 * needs process context so we must queue
 */
static void scsi_tgt_cmd_done(struct scsi_cmnd *cmd)
{
	struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;

	dprintk("cmd %p %u\n", cmd, rq_data_dir(cmd->request));

	scsi_tgt_uspace_send_status(cmd, tcmd->itn_id, tcmd->tag);

	if (scsi_sglist(cmd))
		scsi_free_sgtable(cmd);

	queue_work(scsi_tgtd, &tcmd->work);
}

static int scsi_tgt_transfer_response(struct scsi_cmnd *cmd)
{
	struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
	int err;

	dprintk("cmd %p %u\n", cmd, rq_data_dir(cmd->request));

	err = shost->hostt->transfer_response(cmd, scsi_tgt_cmd_done);
	switch (err) {
	case SCSI_MLQUEUE_HOST_BUSY:
	case SCSI_MLQUEUE_DEVICE_BUSY:
		return -EAGAIN;
	}
	return 0;
}

static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask)
{
	struct request *rq = cmd->request;
	int count;

	cmd->use_sg = rq->nr_phys_segments;
	if (scsi_alloc_sgtable(cmd, gfp_mask))
		return -ENOMEM;

	cmd->request_bufflen = rq->data_len;

	dprintk("cmd %p cnt %d %lu\n", cmd, scsi_sg_count(cmd),
		rq_data_dir(rq));
	count = blk_rq_map_sg(rq->q, rq, scsi_sglist(cmd));
	BUG_ON(count > cmd->use_sg);
	cmd->use_sg = count;
	return 0;
}

/* TODO: test this crap and replace bio_map_user with new interface maybe */
static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd,
			       unsigned long uaddr, unsigned int len, int rw)
{
	struct request_queue *q = cmd->request->q;
	struct request *rq = cmd->request;
	int err;

	dprintk("%lx %u\n", uaddr, len);
	err = blk_rq_map_user(q, rq, (void *)uaddr, len);
	if (err) {
		/*
		 * TODO: need to fixup sg_tablesize, max_segment_size,
		 * max_sectors, etc for modern HW and software drivers
		 * where this value is bogus.
		 *
		 * TODO2: we can alloc a reserve buffer of max size
		 * we can handle and do the slow copy path for really large
		 * IO.
		 */
		eprintk("Could not handle request of size %u.\n", len);
		return err;
	}

	tcmd->bio = rq->bio;
	err = scsi_tgt_init_cmd(cmd, GFP_KERNEL);
	if (err)
		goto unmap_rq;

	return 0;

unmap_rq:
	scsi_unmap_user_pages(tcmd);
	return err;
}

static int scsi_tgt_copy_sense(struct scsi_cmnd *cmd, unsigned long uaddr,
				unsigned len)
{
	char __user *p = (char __user *) uaddr;

	if (copy_from_user(cmd->sense_buffer, p,
			   min_t(unsigned, SCSI_SENSE_BUFFERSIZE, len))) {
		printk(KERN_ERR "Could not copy the sense buffer\n");
		return -EIO;
	}
	return 0;
}

static int scsi_tgt_abort_cmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
{
	struct scsi_tgt_cmd *tcmd;
	int err;

	err = shost->hostt->eh_abort_handler(cmd);
	if (err)
		eprintk("fail to abort %p\n", cmd);

	tcmd = cmd->request->end_io_data;
	scsi_tgt_cmd_destroy(&tcmd->work);
	return err;
}

static struct request *tgt_cmd_hash_lookup(struct request_queue *q, u64 tag)
{
	struct scsi_tgt_queuedata *qdata = q->queuedata;
	struct request *rq = NULL;
	struct list_head *head;
	struct scsi_tgt_cmd *tcmd;
	unsigned long flags;

	head = &qdata->cmd_hash[cmd_hashfn(tag)];
	spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
	list_for_each_entry(tcmd, head, hash_list) {
		if (tcmd->tag == tag) {
			rq = tcmd->rq;
			list_del(&tcmd->hash_list);
			break;
		}
	}
	spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);

	return rq;
}

int scsi_tgt_kspace_exec(int host_no, u64 itn_id, int result, u64 tag,
			 unsigned long uaddr, u32 len, unsigned long sense_uaddr,
			 u32 sense_len, u8 rw)
{
	struct Scsi_Host *shost;
	struct scsi_cmnd *cmd;
	struct request *rq;
	struct scsi_tgt_cmd *tcmd;
	int err = 0;

	dprintk("%d %llu %d %u %lx %u\n", host_no, (unsigned long long) tag,
		result, len, uaddr, rw);

	/* TODO: replace with a O(1) alg */
	shost = scsi_host_lookup(host_no);
	if (IS_ERR(shost)) {
		printk(KERN_ERR "Could not find host no %d\n", host_no);
		return -EINVAL;
	}

	if (!shost->uspace_req_q) {
		printk(KERN_ERR "Not target scsi host %d\n", host_no);
		goto done;
	}

	rq = tgt_cmd_hash_lookup(shost->uspace_req_q, tag);
	if (!rq) {
		printk(KERN_ERR "Could not find tag %llu\n",
		       (unsigned long long) tag);
		err = -EINVAL;
		goto done;
	}
	cmd = rq->special;

	dprintk("cmd %p scb %x result %d len %d bufflen %u %u %x\n",
		cmd, cmd->cmnd[0], result, len, scsi_bufflen(cmd),
		rq_data_dir(rq), cmd->cmnd[0]);

	if (result == TASK_ABORTED) {
		scsi_tgt_abort_cmd(shost, cmd);
		goto done;
	}
	/*
	 * store the userspace values here, the working values are
	 * in the request_* values
	 */
	tcmd = cmd->request->end_io_data;
	cmd->result = result;

	if (cmd->result == SAM_STAT_CHECK_CONDITION)
		scsi_tgt_copy_sense(cmd, sense_uaddr, sense_len);

	if (len) {
		err = scsi_map_user_pages(rq->end_io_data, cmd, uaddr, len, rw);
		if (err) {
			/*
			 * user-space daemon bugs or OOM
			 * TODO: we can do better for OOM.
			 */
			struct scsi_tgt_queuedata *qdata;
			struct list_head *head;
			unsigned long flags;

			eprintk("cmd %p ret %d uaddr %lx len %d rw %d\n",
				cmd, err, uaddr, len, rw);

			qdata = shost->uspace_req_q->queuedata;
			head = &qdata->cmd_hash[cmd_hashfn(tcmd->tag)];

			spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
			list_add(&tcmd->hash_list, head);
			spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);

			goto done;
		}
	}
	err = scsi_tgt_transfer_response(cmd);
done:
	scsi_host_put(shost);
	return err;
}

int scsi_tgt_tsk_mgmt_request(struct Scsi_Host *shost, u64 itn_id,
			      int function, u64 tag, struct scsi_lun *scsilun,
			      void *data)
{
	int err;

	/* TODO: need to retry if this fails. */
	err = scsi_tgt_uspace_send_tsk_mgmt(shost->host_no, itn_id,
					    function, tag, scsilun, data);
	if (err < 0)
		eprintk("The task management request lost!\n");
	return err;
}
EXPORT_SYMBOL_GPL(scsi_tgt_tsk_mgmt_request);

int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 itn_id, u64 mid, int result)
{
	struct Scsi_Host *shost;
	int err = -EINVAL;

	dprintk("%d %d %llx\n", host_no, result, (unsigned long long) mid);

	shost = scsi_host_lookup(host_no);
	if (IS_ERR(shost)) {
		printk(KERN_ERR "Could not find host no %d\n", host_no);
		return err;
	}

	if (!shost->uspace_req_q) {
		printk(KERN_ERR "Not target scsi host %d\n", host_no);
		goto done;
	}

	err = shost->transportt->tsk_mgmt_response(shost, itn_id, mid, result);
done:
	scsi_host_put(shost);
	return err;
}

int scsi_tgt_it_nexus_create(struct Scsi_Host *shost, u64 itn_id,
			     char *initiator)
{
	int err;

	/* TODO: need to retry if this fails. */
	err = scsi_tgt_uspace_send_it_nexus_request(shost->host_no, itn_id, 0,
						    initiator);
	if (err < 0)
		eprintk("The i_t_neuxs request lost, %d %llx!\n",
			shost->host_no, (unsigned long long)itn_id);
	return err;
}
EXPORT_SYMBOL_GPL(scsi_tgt_it_nexus_create);

int scsi_tgt_it_nexus_destroy(struct Scsi_Host *shost, u64 itn_id)
{
	int err;

	/* TODO: need to retry if this fails. */
	err = scsi_tgt_uspace_send_it_nexus_request(shost->host_no,
						    itn_id, 1, NULL);
	if (err < 0)
		eprintk("The i_t_neuxs request lost, %d %llx!\n",
			shost->host_no, (unsigned long long)itn_id);
	return err;
}
EXPORT_SYMBOL_GPL(scsi_tgt_it_nexus_destroy);

int scsi_tgt_kspace_it_nexus_rsp(int host_no, u64 itn_id, int result)
{
	struct Scsi_Host *shost;
	int err = -EINVAL;

	dprintk("%d %d%llx\n", host_no, result, (unsigned long long)itn_id);

	shost = scsi_host_lookup(host_no);
	if (IS_ERR(shost)) {
		printk(KERN_ERR "Could not find host no %d\n", host_no);
		return err;
	}

	if (!shost->uspace_req_q) {
		printk(KERN_ERR "Not target scsi host %d\n", host_no);
		goto done;
	}

	err = shost->transportt->it_nexus_response(shost, itn_id, result);
done:
	scsi_host_put(shost);
	return err;
}

static int __init scsi_tgt_init(void)
{
	int err;

	scsi_tgt_cmd_cache = kmem_cache_create("scsi_tgt_cmd",
					       sizeof(struct scsi_tgt_cmd),
					       0, 0, NULL);
	if (!scsi_tgt_cmd_cache)
		return -ENOMEM;

	scsi_tgtd = create_workqueue("scsi_tgtd");
	if (!scsi_tgtd) {
		err = -ENOMEM;
		goto free_kmemcache;
	}

	err = scsi_tgt_if_init();
	if (err)
		goto destroy_wq;

	return 0;

destroy_wq:
	destroy_workqueue(scsi_tgtd);
free_kmemcache:
	kmem_cache_destroy(scsi_tgt_cmd_cache);
	return err;
}

static void __exit scsi_tgt_exit(void)
{
	destroy_workqueue(scsi_tgtd);
	scsi_tgt_if_exit();
	kmem_cache_destroy(scsi_tgt_cmd_cache);
}

module_init(scsi_tgt_init);
module_exit(scsi_tgt_exit);

MODULE_DESCRIPTION("SCSI target core");
MODULE_LICENSE("GPL");