target/tcm_fc: fix the lockdep warning due to inconsistent lock state
[linux-2.6.git] / drivers / target / target_core_iblock.c
1 /*******************************************************************************
2  * Filename:  target_core_iblock.c
3  *
4  * This file contains the Storage Engine  <-> Linux BlockIO transport
5  * specific functions.
6  *
7  * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
8  * Copyright (c) 2005, 2006, 2007 SBE, Inc.
9  * Copyright (c) 2007-2010 Rising Tide Systems
10  * Copyright (c) 2008-2010 Linux-iSCSI.org
11  *
12  * Nicholas A. Bellinger <nab@kernel.org>
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2 of the License, or
17  * (at your option) any later version.
18  *
19  * This program is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22  * GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with this program; if not, write to the Free Software
26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27  *
28  ******************************************************************************/
29
30 #include <linux/string.h>
31 #include <linux/parser.h>
32 #include <linux/timer.h>
33 #include <linux/fs.h>
34 #include <linux/blkdev.h>
35 #include <linux/slab.h>
36 #include <linux/spinlock.h>
37 #include <linux/bio.h>
38 #include <linux/genhd.h>
39 #include <linux/file.h>
40 #include <linux/module.h>
41 #include <scsi/scsi.h>
42 #include <scsi/scsi_host.h>
43
44 #include <target/target_core_base.h>
45 #include <target/target_core_backend.h>
46
47 #include "target_core_iblock.h"
48
49 #define IBLOCK_MAX_BIO_PER_TASK  32     /* max # of bios to submit at a time */
50 #define IBLOCK_BIO_POOL_SIZE    128
51
52 static struct se_subsystem_api iblock_template;
53
54 static void iblock_bio_done(struct bio *, int);
55
56 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
57  *
58  *
59  */
60 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
61 {
62         pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
63                 " Generic Target Core Stack %s\n", hba->hba_id,
64                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
65         return 0;
66 }
67
68 static void iblock_detach_hba(struct se_hba *hba)
69 {
70 }
71
72 static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
73 {
74         struct iblock_dev *ib_dev = NULL;
75
76         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
77         if (!ib_dev) {
78                 pr_err("Unable to allocate struct iblock_dev\n");
79                 return NULL;
80         }
81
82         pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
83
84         return ib_dev;
85 }
86
87 static struct se_device *iblock_create_virtdevice(
88         struct se_hba *hba,
89         struct se_subsystem_dev *se_dev,
90         void *p)
91 {
92         struct iblock_dev *ib_dev = p;
93         struct se_device *dev;
94         struct se_dev_limits dev_limits;
95         struct block_device *bd = NULL;
96         struct request_queue *q;
97         struct queue_limits *limits;
98         u32 dev_flags = 0;
99         int ret = -EINVAL;
100
101         if (!ib_dev) {
102                 pr_err("Unable to locate struct iblock_dev parameter\n");
103                 return ERR_PTR(ret);
104         }
105         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
106
107         ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
108         if (!ib_dev->ibd_bio_set) {
109                 pr_err("IBLOCK: Unable to create bioset()\n");
110                 return ERR_PTR(-ENOMEM);
111         }
112         pr_debug("IBLOCK: Created bio_set()\n");
113         /*
114          * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
115          * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
116          */
117         pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
118                         ib_dev->ibd_udev_path);
119
120         bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
121                                 FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
122         if (IS_ERR(bd)) {
123                 ret = PTR_ERR(bd);
124                 goto failed;
125         }
126         /*
127          * Setup the local scope queue_limits from struct request_queue->limits
128          * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
129          */
130         q = bdev_get_queue(bd);
131         limits = &dev_limits.limits;
132         limits->logical_block_size = bdev_logical_block_size(bd);
133         limits->max_hw_sectors = UINT_MAX;
134         limits->max_sectors = UINT_MAX;
135         dev_limits.hw_queue_depth = q->nr_requests;
136         dev_limits.queue_depth = q->nr_requests;
137
138         ib_dev->ibd_bd = bd;
139
140         dev = transport_add_device_to_core_hba(hba,
141                         &iblock_template, se_dev, dev_flags, ib_dev,
142                         &dev_limits, "IBLOCK", IBLOCK_VERSION);
143         if (!dev)
144                 goto failed;
145
146         /*
147          * Check if the underlying struct block_device request_queue supports
148          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
149          * in ATA and we need to set TPE=1
150          */
151         if (blk_queue_discard(q)) {
152                 dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count =
153                                 q->limits.max_discard_sectors;
154                 /*
155                  * Currently hardcoded to 1 in Linux/SCSI code..
156                  */
157                 dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count = 1;
158                 dev->se_sub_dev->se_dev_attrib.unmap_granularity =
159                                 q->limits.discard_granularity >> 9;
160                 dev->se_sub_dev->se_dev_attrib.unmap_granularity_alignment =
161                                 q->limits.discard_alignment;
162
163                 pr_debug("IBLOCK: BLOCK Discard support available,"
164                                 " disabled by default\n");
165         }
166
167         if (blk_queue_nonrot(q))
168                 dev->se_sub_dev->se_dev_attrib.is_nonrot = 1;
169
170         return dev;
171
172 failed:
173         if (ib_dev->ibd_bio_set) {
174                 bioset_free(ib_dev->ibd_bio_set);
175                 ib_dev->ibd_bio_set = NULL;
176         }
177         ib_dev->ibd_bd = NULL;
178         return ERR_PTR(ret);
179 }
180
181 static void iblock_free_device(void *p)
182 {
183         struct iblock_dev *ib_dev = p;
184
185         if (ib_dev->ibd_bd != NULL)
186                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
187         if (ib_dev->ibd_bio_set != NULL)
188                 bioset_free(ib_dev->ibd_bio_set);
189         kfree(ib_dev);
190 }
191
192 static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
193 {
194         return container_of(task, struct iblock_req, ib_task);
195 }
196
197 static struct se_task *
198 iblock_alloc_task(unsigned char *cdb)
199 {
200         struct iblock_req *ib_req;
201
202         ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
203         if (!ib_req) {
204                 pr_err("Unable to allocate memory for struct iblock_req\n");
205                 return NULL;
206         }
207
208         atomic_set(&ib_req->pending, 1);
209         return &ib_req->ib_task;
210 }
211
212 static unsigned long long iblock_emulate_read_cap_with_block_size(
213         struct se_device *dev,
214         struct block_device *bd,
215         struct request_queue *q)
216 {
217         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
218                                         bdev_logical_block_size(bd)) - 1);
219         u32 block_size = bdev_logical_block_size(bd);
220
221         if (block_size == dev->se_sub_dev->se_dev_attrib.block_size)
222                 return blocks_long;
223
224         switch (block_size) {
225         case 4096:
226                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
227                 case 2048:
228                         blocks_long <<= 1;
229                         break;
230                 case 1024:
231                         blocks_long <<= 2;
232                         break;
233                 case 512:
234                         blocks_long <<= 3;
235                 default:
236                         break;
237                 }
238                 break;
239         case 2048:
240                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
241                 case 4096:
242                         blocks_long >>= 1;
243                         break;
244                 case 1024:
245                         blocks_long <<= 1;
246                         break;
247                 case 512:
248                         blocks_long <<= 2;
249                         break;
250                 default:
251                         break;
252                 }
253                 break;
254         case 1024:
255                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
256                 case 4096:
257                         blocks_long >>= 2;
258                         break;
259                 case 2048:
260                         blocks_long >>= 1;
261                         break;
262                 case 512:
263                         blocks_long <<= 1;
264                         break;
265                 default:
266                         break;
267                 }
268                 break;
269         case 512:
270                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
271                 case 4096:
272                         blocks_long >>= 3;
273                         break;
274                 case 2048:
275                         blocks_long >>= 2;
276                         break;
277                 case 1024:
278                         blocks_long >>= 1;
279                         break;
280                 default:
281                         break;
282                 }
283                 break;
284         default:
285                 break;
286         }
287
288         return blocks_long;
289 }
290
291 static void iblock_end_io_flush(struct bio *bio, int err)
292 {
293         struct se_cmd *cmd = bio->bi_private;
294
295         if (err)
296                 pr_err("IBLOCK: cache flush failed: %d\n", err);
297
298         if (cmd)
299                 transport_complete_sync_cache(cmd, err == 0);
300         bio_put(bio);
301 }
302
303 /*
304  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
305  * always flush the whole cache.
306  */
307 static void iblock_emulate_sync_cache(struct se_task *task)
308 {
309         struct se_cmd *cmd = task->task_se_cmd;
310         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
311         int immed = (cmd->t_task_cdb[1] & 0x2);
312         struct bio *bio;
313
314         /*
315          * If the Immediate bit is set, queue up the GOOD response
316          * for this SYNCHRONIZE_CACHE op.
317          */
318         if (immed)
319                 transport_complete_sync_cache(cmd, 1);
320
321         bio = bio_alloc(GFP_KERNEL, 0);
322         bio->bi_end_io = iblock_end_io_flush;
323         bio->bi_bdev = ib_dev->ibd_bd;
324         if (!immed)
325                 bio->bi_private = cmd;
326         submit_bio(WRITE_FLUSH, bio);
327 }
328
329 static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
330 {
331         struct iblock_dev *ibd = dev->dev_ptr;
332         struct block_device *bd = ibd->ibd_bd;
333         int barrier = 0;
334
335         return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
336 }
337
338 static void iblock_free_task(struct se_task *task)
339 {
340         kfree(IBLOCK_REQ(task));
341 }
342
343 enum {
344         Opt_udev_path, Opt_force, Opt_err
345 };
346
347 static match_table_t tokens = {
348         {Opt_udev_path, "udev_path=%s"},
349         {Opt_force, "force=%d"},
350         {Opt_err, NULL}
351 };
352
353 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
354                                                struct se_subsystem_dev *se_dev,
355                                                const char *page, ssize_t count)
356 {
357         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
358         char *orig, *ptr, *arg_p, *opts;
359         substring_t args[MAX_OPT_ARGS];
360         int ret = 0, token;
361
362         opts = kstrdup(page, GFP_KERNEL);
363         if (!opts)
364                 return -ENOMEM;
365
366         orig = opts;
367
368         while ((ptr = strsep(&opts, ",\n")) != NULL) {
369                 if (!*ptr)
370                         continue;
371
372                 token = match_token(ptr, tokens, args);
373                 switch (token) {
374                 case Opt_udev_path:
375                         if (ib_dev->ibd_bd) {
376                                 pr_err("Unable to set udev_path= while"
377                                         " ib_dev->ibd_bd exists\n");
378                                 ret = -EEXIST;
379                                 goto out;
380                         }
381                         arg_p = match_strdup(&args[0]);
382                         if (!arg_p) {
383                                 ret = -ENOMEM;
384                                 break;
385                         }
386                         snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
387                                         "%s", arg_p);
388                         kfree(arg_p);
389                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
390                                         ib_dev->ibd_udev_path);
391                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
392                         break;
393                 case Opt_force:
394                         break;
395                 default:
396                         break;
397                 }
398         }
399
400 out:
401         kfree(orig);
402         return (!ret) ? count : ret;
403 }
404
405 static ssize_t iblock_check_configfs_dev_params(
406         struct se_hba *hba,
407         struct se_subsystem_dev *se_dev)
408 {
409         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
410
411         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
412                 pr_err("Missing udev_path= parameters for IBLOCK\n");
413                 return -EINVAL;
414         }
415
416         return 0;
417 }
418
419 static ssize_t iblock_show_configfs_dev_params(
420         struct se_hba *hba,
421         struct se_subsystem_dev *se_dev,
422         char *b)
423 {
424         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
425         struct block_device *bd = ibd->ibd_bd;
426         char buf[BDEVNAME_SIZE];
427         ssize_t bl = 0;
428
429         if (bd)
430                 bl += sprintf(b + bl, "iBlock device: %s",
431                                 bdevname(bd, buf));
432         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
433                 bl += sprintf(b + bl, "  UDEV PATH: %s\n",
434                                 ibd->ibd_udev_path);
435         } else
436                 bl += sprintf(b + bl, "\n");
437
438         bl += sprintf(b + bl, "        ");
439         if (bd) {
440                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
441                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
442                         "" : (bd->bd_holder == ibd) ?
443                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
444         } else {
445                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
446         }
447
448         return bl;
449 }
450
451 static void iblock_bio_destructor(struct bio *bio)
452 {
453         struct se_task *task = bio->bi_private;
454         struct iblock_dev *ib_dev = task->task_se_cmd->se_dev->dev_ptr;
455
456         bio_free(bio, ib_dev->ibd_bio_set);
457 }
458
459 static struct bio *
460 iblock_get_bio(struct se_task *task, sector_t lba, u32 sg_num)
461 {
462         struct iblock_dev *ib_dev = task->task_se_cmd->se_dev->dev_ptr;
463         struct iblock_req *ib_req = IBLOCK_REQ(task);
464         struct bio *bio;
465
466         /*
467          * Only allocate as many vector entries as the bio code allows us to,
468          * we'll loop later on until we have handled the whole request.
469          */
470         if (sg_num > BIO_MAX_PAGES)
471                 sg_num = BIO_MAX_PAGES;
472
473         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
474         if (!bio) {
475                 pr_err("Unable to allocate memory for bio\n");
476                 return NULL;
477         }
478
479         pr_debug("Allocated bio: %p task_sg_nents: %u using ibd_bio_set:"
480                 " %p\n", bio, task->task_sg_nents, ib_dev->ibd_bio_set);
481         pr_debug("Allocated bio: %p task_size: %u\n", bio, task->task_size);
482
483         bio->bi_bdev = ib_dev->ibd_bd;
484         bio->bi_private = task;
485         bio->bi_destructor = iblock_bio_destructor;
486         bio->bi_end_io = &iblock_bio_done;
487         bio->bi_sector = lba;
488         atomic_inc(&ib_req->pending);
489
490         pr_debug("Set bio->bi_sector: %llu\n", (unsigned long long)bio->bi_sector);
491         pr_debug("Set ib_req->pending: %d\n", atomic_read(&ib_req->pending));
492         return bio;
493 }
494
495 static void iblock_submit_bios(struct bio_list *list, int rw)
496 {
497         struct blk_plug plug;
498         struct bio *bio;
499
500         blk_start_plug(&plug);
501         while ((bio = bio_list_pop(list)))
502                 submit_bio(rw, bio);
503         blk_finish_plug(&plug);
504 }
505
506 static int iblock_do_task(struct se_task *task)
507 {
508         struct se_cmd *cmd = task->task_se_cmd;
509         struct se_device *dev = cmd->se_dev;
510         struct iblock_req *ibr = IBLOCK_REQ(task);
511         struct bio *bio;
512         struct bio_list list;
513         struct scatterlist *sg;
514         u32 i, sg_num = task->task_sg_nents;
515         sector_t block_lba;
516         unsigned bio_cnt;
517         int rw;
518
519         if (task->task_data_direction == DMA_TO_DEVICE) {
520                 /*
521                  * Force data to disk if we pretend to not have a volatile
522                  * write cache, or the initiator set the Force Unit Access bit.
523                  */
524                 if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
525                     (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
526                      (cmd->se_cmd_flags & SCF_FUA)))
527                         rw = WRITE_FUA;
528                 else
529                         rw = WRITE;
530         } else {
531                 rw = READ;
532         }
533
534         /*
535          * Do starting conversion up from non 512-byte blocksize with
536          * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
537          */
538         if (dev->se_sub_dev->se_dev_attrib.block_size == 4096)
539                 block_lba = (task->task_lba << 3);
540         else if (dev->se_sub_dev->se_dev_attrib.block_size == 2048)
541                 block_lba = (task->task_lba << 2);
542         else if (dev->se_sub_dev->se_dev_attrib.block_size == 1024)
543                 block_lba = (task->task_lba << 1);
544         else if (dev->se_sub_dev->se_dev_attrib.block_size == 512)
545                 block_lba = task->task_lba;
546         else {
547                 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
548                                 " %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
549                 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
550                 return -ENOSYS;
551         }
552
553         bio = iblock_get_bio(task, block_lba, sg_num);
554         if (!bio) {
555                 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
556                 return -ENOMEM;
557         }
558
559         bio_list_init(&list);
560         bio_list_add(&list, bio);
561         bio_cnt = 1;
562
563         for_each_sg(task->task_sg, sg, task->task_sg_nents, i) {
564                 /*
565                  * XXX: if the length the device accepts is shorter than the
566                  *      length of the S/G list entry this will cause and
567                  *      endless loop.  Better hope no driver uses huge pages.
568                  */
569                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
570                                 != sg->length) {
571                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
572                                 iblock_submit_bios(&list, rw);
573                                 bio_cnt = 0;
574                         }
575
576                         bio = iblock_get_bio(task, block_lba, sg_num);
577                         if (!bio)
578                                 goto fail;
579                         bio_list_add(&list, bio);
580                         bio_cnt++;
581                 }
582
583                 /* Always in 512 byte units for Linux/Block */
584                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
585                 sg_num--;
586         }
587
588         iblock_submit_bios(&list, rw);
589
590         if (atomic_dec_and_test(&ibr->pending)) {
591                 transport_complete_task(task,
592                                 !atomic_read(&ibr->ib_bio_err_cnt));
593         }
594         return 0;
595
596 fail:
597         while ((bio = bio_list_pop(&list)))
598                 bio_put(bio);
599         cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
600         return -ENOMEM;
601 }
602
603 static u32 iblock_get_device_rev(struct se_device *dev)
604 {
605         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
606 }
607
608 static u32 iblock_get_device_type(struct se_device *dev)
609 {
610         return TYPE_DISK;
611 }
612
613 static sector_t iblock_get_blocks(struct se_device *dev)
614 {
615         struct iblock_dev *ibd = dev->dev_ptr;
616         struct block_device *bd = ibd->ibd_bd;
617         struct request_queue *q = bdev_get_queue(bd);
618
619         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
620 }
621
622 static void iblock_bio_done(struct bio *bio, int err)
623 {
624         struct se_task *task = bio->bi_private;
625         struct iblock_req *ibr = IBLOCK_REQ(task);
626
627         /*
628          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
629          */
630         if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
631                 err = -EIO;
632
633         if (err != 0) {
634                 pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
635                         " err: %d\n", bio, err);
636                 /*
637                  * Bump the ib_bio_err_cnt and release bio.
638                  */
639                 atomic_inc(&ibr->ib_bio_err_cnt);
640                 smp_mb__after_atomic_inc();
641         }
642
643         bio_put(bio);
644
645         if (!atomic_dec_and_test(&ibr->pending))
646                 return;
647
648         pr_debug("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
649                  task, bio, task->task_lba,
650                  (unsigned long long)bio->bi_sector, err);
651
652         transport_complete_task(task, !atomic_read(&ibr->ib_bio_err_cnt));
653 }
654
655 static struct se_subsystem_api iblock_template = {
656         .name                   = "iblock",
657         .owner                  = THIS_MODULE,
658         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
659         .write_cache_emulated   = 1,
660         .fua_write_emulated     = 1,
661         .attach_hba             = iblock_attach_hba,
662         .detach_hba             = iblock_detach_hba,
663         .allocate_virtdevice    = iblock_allocate_virtdevice,
664         .create_virtdevice      = iblock_create_virtdevice,
665         .free_device            = iblock_free_device,
666         .alloc_task             = iblock_alloc_task,
667         .do_task                = iblock_do_task,
668         .do_discard             = iblock_do_discard,
669         .do_sync_cache          = iblock_emulate_sync_cache,
670         .free_task              = iblock_free_task,
671         .check_configfs_dev_params = iblock_check_configfs_dev_params,
672         .set_configfs_dev_params = iblock_set_configfs_dev_params,
673         .show_configfs_dev_params = iblock_show_configfs_dev_params,
674         .get_device_rev         = iblock_get_device_rev,
675         .get_device_type        = iblock_get_device_type,
676         .get_blocks             = iblock_get_blocks,
677 };
678
679 static int __init iblock_module_init(void)
680 {
681         return transport_subsystem_register(&iblock_template);
682 }
683
684 static void iblock_module_exit(void)
685 {
686         transport_subsystem_release(&iblock_template);
687 }
688
689 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
690 MODULE_AUTHOR("nab@Linux-iSCSI.org");
691 MODULE_LICENSE("GPL");
692
693 module_init(iblock_module_init);
694 module_exit(iblock_module_exit);