1 /*******************************************************************************
2 * Filename: target_core_iblock.c
4 * This file contains the Storage Engine <-> Linux BlockIO transport
7 * (c) Copyright 2003-2013 Datera, Inc.
9 * Nicholas A. Bellinger <nab@kernel.org>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
25 ******************************************************************************/
27 #include <linux/string.h>
28 #include <linux/parser.h>
29 #include <linux/timer.h>
31 #include <linux/blkdev.h>
32 #include <linux/slab.h>
33 #include <linux/spinlock.h>
34 #include <linux/bio.h>
35 #include <linux/genhd.h>
36 #include <linux/file.h>
37 #include <linux/module.h>
38 #include <scsi/scsi_proto.h>
39 #include <asm/unaligned.h>
41 #include <target/target_core_base.h>
42 #include <target/target_core_backend.h>
44 #include "target_core_iblock.h"
46 #define IBLOCK_MAX_BIO_PER_TASK 32 /* max # of bios to submit at a time */
47 #define IBLOCK_BIO_POOL_SIZE 128
49 static inline struct iblock_dev
*IBLOCK_DEV(struct se_device
*dev
)
51 return container_of(dev
, struct iblock_dev
, dev
);
55 static int iblock_attach_hba(struct se_hba
*hba
, u32 host_id
)
57 pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
58 " Generic Target Core Stack %s\n", hba
->hba_id
,
59 IBLOCK_VERSION
, TARGET_CORE_VERSION
);
63 static void iblock_detach_hba(struct se_hba
*hba
)
67 static struct se_device
*iblock_alloc_device(struct se_hba
*hba
, const char *name
)
69 struct iblock_dev
*ib_dev
= NULL
;
71 ib_dev
= kzalloc(sizeof(struct iblock_dev
), GFP_KERNEL
);
73 pr_err("Unable to allocate struct iblock_dev\n");
77 pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name
);
82 static int iblock_configure_device(struct se_device
*dev
)
84 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
85 struct request_queue
*q
;
86 struct block_device
*bd
= NULL
;
87 struct blk_integrity
*bi
;
91 if (!(ib_dev
->ibd_flags
& IBDF_HAS_UDEV_PATH
)) {
92 pr_err("Missing udev_path= parameters for IBLOCK\n");
96 ib_dev
->ibd_bio_set
= bioset_create(IBLOCK_BIO_POOL_SIZE
, 0);
97 if (!ib_dev
->ibd_bio_set
) {
98 pr_err("IBLOCK: Unable to create bioset\n");
102 pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
103 ib_dev
->ibd_udev_path
);
105 mode
= FMODE_READ
|FMODE_EXCL
;
106 if (!ib_dev
->ibd_readonly
)
109 dev
->dev_flags
|= DF_READ_ONLY
;
111 bd
= blkdev_get_by_path(ib_dev
->ibd_udev_path
, mode
, ib_dev
);
114 goto out_free_bioset
;
118 q
= bdev_get_queue(bd
);
120 dev
->dev_attrib
.hw_block_size
= bdev_logical_block_size(bd
);
121 dev
->dev_attrib
.hw_max_sectors
= queue_max_hw_sectors(q
);
122 dev
->dev_attrib
.hw_queue_depth
= q
->nr_requests
;
124 if (target_configure_unmap_from_queue(&dev
->dev_attrib
, q
,
125 dev
->dev_attrib
.hw_block_size
))
126 pr_debug("IBLOCK: BLOCK Discard support available,"
127 " disabled by default\n");
130 * Enable write same emulation for IBLOCK and use 0xFFFF as
131 * the smaller WRITE_SAME(10) only has a two-byte block count.
133 dev
->dev_attrib
.max_write_same_len
= 0xFFFF;
135 if (blk_queue_nonrot(q
))
136 dev
->dev_attrib
.is_nonrot
= 1;
138 bi
= bdev_get_integrity(bd
);
140 struct bio_set
*bs
= ib_dev
->ibd_bio_set
;
142 if (!strcmp(bi
->profile
->name
, "T10-DIF-TYPE3-IP") ||
143 !strcmp(bi
->profile
->name
, "T10-DIF-TYPE1-IP")) {
144 pr_err("IBLOCK export of blk_integrity: %s not"
145 " supported\n", bi
->profile
->name
);
150 if (!strcmp(bi
->profile
->name
, "T10-DIF-TYPE3-CRC")) {
151 dev
->dev_attrib
.pi_prot_type
= TARGET_DIF_TYPE3_PROT
;
152 } else if (!strcmp(bi
->profile
->name
, "T10-DIF-TYPE1-CRC")) {
153 dev
->dev_attrib
.pi_prot_type
= TARGET_DIF_TYPE1_PROT
;
156 if (dev
->dev_attrib
.pi_prot_type
) {
157 if (bioset_integrity_create(bs
, IBLOCK_BIO_POOL_SIZE
) < 0) {
158 pr_err("Unable to allocate bioset for PI\n");
162 pr_debug("IBLOCK setup BIP bs->bio_integrity_pool: %p\n",
163 bs
->bio_integrity_pool
);
165 dev
->dev_attrib
.hw_pi_prot_type
= dev
->dev_attrib
.pi_prot_type
;
171 blkdev_put(ib_dev
->ibd_bd
, FMODE_WRITE
|FMODE_READ
|FMODE_EXCL
);
173 bioset_free(ib_dev
->ibd_bio_set
);
174 ib_dev
->ibd_bio_set
= NULL
;
179 static void iblock_dev_call_rcu(struct rcu_head
*p
)
181 struct se_device
*dev
= container_of(p
, struct se_device
, rcu_head
);
182 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
187 static void iblock_free_device(struct se_device
*dev
)
189 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
191 if (ib_dev
->ibd_bd
!= NULL
)
192 blkdev_put(ib_dev
->ibd_bd
, FMODE_WRITE
|FMODE_READ
|FMODE_EXCL
);
193 if (ib_dev
->ibd_bio_set
!= NULL
)
194 bioset_free(ib_dev
->ibd_bio_set
);
196 call_rcu(&dev
->rcu_head
, iblock_dev_call_rcu
);
199 static unsigned long long iblock_emulate_read_cap_with_block_size(
200 struct se_device
*dev
,
201 struct block_device
*bd
,
202 struct request_queue
*q
)
204 unsigned long long blocks_long
= (div_u64(i_size_read(bd
->bd_inode
),
205 bdev_logical_block_size(bd
)) - 1);
206 u32 block_size
= bdev_logical_block_size(bd
);
208 if (block_size
== dev
->dev_attrib
.block_size
)
211 switch (block_size
) {
213 switch (dev
->dev_attrib
.block_size
) {
227 switch (dev
->dev_attrib
.block_size
) {
242 switch (dev
->dev_attrib
.block_size
) {
257 switch (dev
->dev_attrib
.block_size
) {
278 static void iblock_complete_cmd(struct se_cmd
*cmd
)
280 struct iblock_req
*ibr
= cmd
->priv
;
283 if (!atomic_dec_and_test(&ibr
->pending
))
286 if (atomic_read(&ibr
->ib_bio_err_cnt
))
287 status
= SAM_STAT_CHECK_CONDITION
;
289 status
= SAM_STAT_GOOD
;
291 target_complete_cmd(cmd
, status
);
295 static void iblock_bio_done(struct bio
*bio
)
297 struct se_cmd
*cmd
= bio
->bi_private
;
298 struct iblock_req
*ibr
= cmd
->priv
;
301 pr_err("bio error: %p, err: %d\n", bio
, bio
->bi_error
);
303 * Bump the ib_bio_err_cnt and release bio.
305 atomic_inc(&ibr
->ib_bio_err_cnt
);
306 smp_mb__after_atomic();
311 iblock_complete_cmd(cmd
);
315 iblock_get_bio(struct se_cmd
*cmd
, sector_t lba
, u32 sg_num
)
317 struct iblock_dev
*ib_dev
= IBLOCK_DEV(cmd
->se_dev
);
321 * Only allocate as many vector entries as the bio code allows us to,
322 * we'll loop later on until we have handled the whole request.
324 if (sg_num
> BIO_MAX_PAGES
)
325 sg_num
= BIO_MAX_PAGES
;
327 bio
= bio_alloc_bioset(GFP_NOIO
, sg_num
, ib_dev
->ibd_bio_set
);
329 pr_err("Unable to allocate memory for bio\n");
333 bio
->bi_bdev
= ib_dev
->ibd_bd
;
334 bio
->bi_private
= cmd
;
335 bio
->bi_end_io
= &iblock_bio_done
;
336 bio
->bi_iter
.bi_sector
= lba
;
341 static void iblock_submit_bios(struct bio_list
*list
, int rw
)
343 struct blk_plug plug
;
346 blk_start_plug(&plug
);
347 while ((bio
= bio_list_pop(list
)))
349 blk_finish_plug(&plug
);
352 static void iblock_end_io_flush(struct bio
*bio
)
354 struct se_cmd
*cmd
= bio
->bi_private
;
357 pr_err("IBLOCK: cache flush failed: %d\n", bio
->bi_error
);
361 target_complete_cmd(cmd
, SAM_STAT_CHECK_CONDITION
);
363 target_complete_cmd(cmd
, SAM_STAT_GOOD
);
370 * Implement SYCHRONIZE CACHE. Note that we can't handle lba ranges and must
371 * always flush the whole cache.
373 static sense_reason_t
374 iblock_execute_sync_cache(struct se_cmd
*cmd
)
376 struct iblock_dev
*ib_dev
= IBLOCK_DEV(cmd
->se_dev
);
377 int immed
= (cmd
->t_task_cdb
[1] & 0x2);
381 * If the Immediate bit is set, queue up the GOOD response
382 * for this SYNCHRONIZE_CACHE op.
385 target_complete_cmd(cmd
, SAM_STAT_GOOD
);
387 bio
= bio_alloc(GFP_KERNEL
, 0);
388 bio
->bi_end_io
= iblock_end_io_flush
;
389 bio
->bi_bdev
= ib_dev
->ibd_bd
;
391 bio
->bi_private
= cmd
;
392 submit_bio(WRITE_FLUSH
, bio
);
396 static sense_reason_t
397 iblock_execute_unmap(struct se_cmd
*cmd
, sector_t lba
, sector_t nolb
)
399 struct block_device
*bdev
= IBLOCK_DEV(cmd
->se_dev
)->ibd_bd
;
400 struct se_device
*dev
= cmd
->se_dev
;
403 ret
= blkdev_issue_discard(bdev
,
404 target_to_linux_sector(dev
, lba
),
405 target_to_linux_sector(dev
, nolb
),
408 pr_err("blkdev_issue_discard() failed: %d\n", ret
);
409 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE
;
415 static sense_reason_t
416 iblock_execute_write_same(struct se_cmd
*cmd
)
418 struct iblock_req
*ibr
;
419 struct scatterlist
*sg
;
421 struct bio_list list
;
422 struct se_device
*dev
= cmd
->se_dev
;
423 sector_t block_lba
= target_to_linux_sector(dev
, cmd
->t_task_lba
);
424 sector_t sectors
= target_to_linux_sector(dev
,
425 sbc_get_write_same_sectors(cmd
));
428 pr_err("WRITE_SAME: Protection information with IBLOCK"
429 " backends not supported\n");
430 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE
;
432 sg
= &cmd
->t_data_sg
[0];
434 if (cmd
->t_data_nents
> 1 ||
435 sg
->length
!= cmd
->se_dev
->dev_attrib
.block_size
) {
436 pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
437 " block_size: %u\n", cmd
->t_data_nents
, sg
->length
,
438 cmd
->se_dev
->dev_attrib
.block_size
);
439 return TCM_INVALID_CDB_FIELD
;
442 ibr
= kzalloc(sizeof(struct iblock_req
), GFP_KERNEL
);
447 bio
= iblock_get_bio(cmd
, block_lba
, 1);
451 bio_list_init(&list
);
452 bio_list_add(&list
, bio
);
454 atomic_set(&ibr
->pending
, 1);
457 while (bio_add_page(bio
, sg_page(sg
), sg
->length
, sg
->offset
)
460 bio
= iblock_get_bio(cmd
, block_lba
, 1);
464 atomic_inc(&ibr
->pending
);
465 bio_list_add(&list
, bio
);
468 /* Always in 512 byte units for Linux/Block */
469 block_lba
+= sg
->length
>> IBLOCK_LBA_SHIFT
;
473 iblock_submit_bios(&list
, WRITE
);
477 while ((bio
= bio_list_pop(&list
)))
482 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE
;
486 Opt_udev_path
, Opt_readonly
, Opt_force
, Opt_err
489 static match_table_t tokens
= {
490 {Opt_udev_path
, "udev_path=%s"},
491 {Opt_readonly
, "readonly=%d"},
492 {Opt_force
, "force=%d"},
496 static ssize_t
iblock_set_configfs_dev_params(struct se_device
*dev
,
497 const char *page
, ssize_t count
)
499 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
500 char *orig
, *ptr
, *arg_p
, *opts
;
501 substring_t args
[MAX_OPT_ARGS
];
503 unsigned long tmp_readonly
;
505 opts
= kstrdup(page
, GFP_KERNEL
);
511 while ((ptr
= strsep(&opts
, ",\n")) != NULL
) {
515 token
= match_token(ptr
, tokens
, args
);
518 if (ib_dev
->ibd_bd
) {
519 pr_err("Unable to set udev_path= while"
520 " ib_dev->ibd_bd exists\n");
524 if (match_strlcpy(ib_dev
->ibd_udev_path
, &args
[0],
525 SE_UDEV_PATH_LEN
) == 0) {
529 pr_debug("IBLOCK: Referencing UDEV path: %s\n",
530 ib_dev
->ibd_udev_path
);
531 ib_dev
->ibd_flags
|= IBDF_HAS_UDEV_PATH
;
534 arg_p
= match_strdup(&args
[0]);
539 ret
= kstrtoul(arg_p
, 0, &tmp_readonly
);
542 pr_err("kstrtoul() failed for"
546 ib_dev
->ibd_readonly
= tmp_readonly
;
547 pr_debug("IBLOCK: readonly: %d\n", ib_dev
->ibd_readonly
);
558 return (!ret
) ? count
: ret
;
561 static ssize_t
iblock_show_configfs_dev_params(struct se_device
*dev
, char *b
)
563 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
564 struct block_device
*bd
= ib_dev
->ibd_bd
;
565 char buf
[BDEVNAME_SIZE
];
569 bl
+= sprintf(b
+ bl
, "iBlock device: %s",
571 if (ib_dev
->ibd_flags
& IBDF_HAS_UDEV_PATH
)
572 bl
+= sprintf(b
+ bl
, " UDEV PATH: %s",
573 ib_dev
->ibd_udev_path
);
574 bl
+= sprintf(b
+ bl
, " readonly: %d\n", ib_dev
->ibd_readonly
);
576 bl
+= sprintf(b
+ bl
, " ");
578 bl
+= sprintf(b
+ bl
, "Major: %d Minor: %d %s\n",
579 MAJOR(bd
->bd_dev
), MINOR(bd
->bd_dev
), (!bd
->bd_contains
) ?
580 "" : (bd
->bd_holder
== ib_dev
) ?
581 "CLAIMED: IBLOCK" : "CLAIMED: OS");
583 bl
+= sprintf(b
+ bl
, "Major: 0 Minor: 0\n");
590 iblock_alloc_bip(struct se_cmd
*cmd
, struct bio
*bio
)
592 struct se_device
*dev
= cmd
->se_dev
;
593 struct blk_integrity
*bi
;
594 struct bio_integrity_payload
*bip
;
595 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
596 struct scatterlist
*sg
;
599 bi
= bdev_get_integrity(ib_dev
->ibd_bd
);
601 pr_err("Unable to locate bio_integrity\n");
605 bip
= bio_integrity_alloc(bio
, GFP_NOIO
, cmd
->t_prot_nents
);
607 pr_err("Unable to allocate bio_integrity_payload\n");
611 bip
->bip_iter
.bi_size
= (cmd
->data_length
/ dev
->dev_attrib
.block_size
) *
613 bip
->bip_iter
.bi_sector
= bio
->bi_iter
.bi_sector
;
615 pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip
->bip_iter
.bi_size
,
616 (unsigned long long)bip
->bip_iter
.bi_sector
);
618 for_each_sg(cmd
->t_prot_sg
, sg
, cmd
->t_prot_nents
, i
) {
620 rc
= bio_integrity_add_page(bio
, sg_page(sg
), sg
->length
,
622 if (rc
!= sg
->length
) {
623 pr_err("bio_integrity_add_page() failed; %d\n", rc
);
627 pr_debug("Added bio integrity page: %p length: %d offset; %d\n",
628 sg_page(sg
), sg
->length
, sg
->offset
);
634 static sense_reason_t
635 iblock_execute_rw(struct se_cmd
*cmd
, struct scatterlist
*sgl
, u32 sgl_nents
,
636 enum dma_data_direction data_direction
)
638 struct se_device
*dev
= cmd
->se_dev
;
639 sector_t block_lba
= target_to_linux_sector(dev
, cmd
->t_task_lba
);
640 struct iblock_req
*ibr
;
641 struct bio
*bio
, *bio_start
;
642 struct bio_list list
;
643 struct scatterlist
*sg
;
644 u32 sg_num
= sgl_nents
;
649 if (data_direction
== DMA_TO_DEVICE
) {
650 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
651 struct request_queue
*q
= bdev_get_queue(ib_dev
->ibd_bd
);
653 * Force writethrough using WRITE_FUA if a volatile write cache
654 * is not enabled, or if initiator set the Force Unit Access bit.
656 if (q
->flush_flags
& REQ_FUA
) {
657 if (cmd
->se_cmd_flags
& SCF_FUA
)
659 else if (!(q
->flush_flags
& REQ_FLUSH
))
670 ibr
= kzalloc(sizeof(struct iblock_req
), GFP_KERNEL
);
676 atomic_set(&ibr
->pending
, 1);
677 iblock_complete_cmd(cmd
);
681 bio
= iblock_get_bio(cmd
, block_lba
, sgl_nents
);
686 bio_list_init(&list
);
687 bio_list_add(&list
, bio
);
689 atomic_set(&ibr
->pending
, 2);
692 for_each_sg(sgl
, sg
, sgl_nents
, i
) {
694 * XXX: if the length the device accepts is shorter than the
695 * length of the S/G list entry this will cause and
696 * endless loop. Better hope no driver uses huge pages.
698 while (bio_add_page(bio
, sg_page(sg
), sg
->length
, sg
->offset
)
700 if (bio_cnt
>= IBLOCK_MAX_BIO_PER_TASK
) {
701 iblock_submit_bios(&list
, rw
);
705 bio
= iblock_get_bio(cmd
, block_lba
, sg_num
);
709 atomic_inc(&ibr
->pending
);
710 bio_list_add(&list
, bio
);
714 /* Always in 512 byte units for Linux/Block */
715 block_lba
+= sg
->length
>> IBLOCK_LBA_SHIFT
;
719 if (cmd
->prot_type
&& dev
->dev_attrib
.pi_prot_type
) {
720 int rc
= iblock_alloc_bip(cmd
, bio_start
);
725 iblock_submit_bios(&list
, rw
);
726 iblock_complete_cmd(cmd
);
730 while ((bio
= bio_list_pop(&list
)))
735 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE
;
738 static sector_t
iblock_get_blocks(struct se_device
*dev
)
740 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
741 struct block_device
*bd
= ib_dev
->ibd_bd
;
742 struct request_queue
*q
= bdev_get_queue(bd
);
744 return iblock_emulate_read_cap_with_block_size(dev
, bd
, q
);
747 static sector_t
iblock_get_alignment_offset_lbas(struct se_device
*dev
)
749 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
750 struct block_device
*bd
= ib_dev
->ibd_bd
;
753 ret
= bdev_alignment_offset(bd
);
757 /* convert offset-bytes to offset-lbas */
758 return ret
/ bdev_logical_block_size(bd
);
761 static unsigned int iblock_get_lbppbe(struct se_device
*dev
)
763 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
764 struct block_device
*bd
= ib_dev
->ibd_bd
;
765 int logs_per_phys
= bdev_physical_block_size(bd
) / bdev_logical_block_size(bd
);
767 return ilog2(logs_per_phys
);
770 static unsigned int iblock_get_io_min(struct se_device
*dev
)
772 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
773 struct block_device
*bd
= ib_dev
->ibd_bd
;
775 return bdev_io_min(bd
);
778 static unsigned int iblock_get_io_opt(struct se_device
*dev
)
780 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
781 struct block_device
*bd
= ib_dev
->ibd_bd
;
783 return bdev_io_opt(bd
);
786 static struct sbc_ops iblock_sbc_ops
= {
787 .execute_rw
= iblock_execute_rw
,
788 .execute_sync_cache
= iblock_execute_sync_cache
,
789 .execute_write_same
= iblock_execute_write_same
,
790 .execute_unmap
= iblock_execute_unmap
,
793 static sense_reason_t
794 iblock_parse_cdb(struct se_cmd
*cmd
)
796 return sbc_parse_cdb(cmd
, &iblock_sbc_ops
);
799 static bool iblock_get_write_cache(struct se_device
*dev
)
801 struct iblock_dev
*ib_dev
= IBLOCK_DEV(dev
);
802 struct block_device
*bd
= ib_dev
->ibd_bd
;
803 struct request_queue
*q
= bdev_get_queue(bd
);
805 return q
->flush_flags
& REQ_FLUSH
;
808 static const struct target_backend_ops iblock_ops
= {
810 .inquiry_prod
= "IBLOCK",
811 .inquiry_rev
= IBLOCK_VERSION
,
812 .owner
= THIS_MODULE
,
813 .attach_hba
= iblock_attach_hba
,
814 .detach_hba
= iblock_detach_hba
,
815 .alloc_device
= iblock_alloc_device
,
816 .configure_device
= iblock_configure_device
,
817 .free_device
= iblock_free_device
,
818 .parse_cdb
= iblock_parse_cdb
,
819 .set_configfs_dev_params
= iblock_set_configfs_dev_params
,
820 .show_configfs_dev_params
= iblock_show_configfs_dev_params
,
821 .get_device_type
= sbc_get_device_type
,
822 .get_blocks
= iblock_get_blocks
,
823 .get_alignment_offset_lbas
= iblock_get_alignment_offset_lbas
,
824 .get_lbppbe
= iblock_get_lbppbe
,
825 .get_io_min
= iblock_get_io_min
,
826 .get_io_opt
= iblock_get_io_opt
,
827 .get_write_cache
= iblock_get_write_cache
,
828 .tb_dev_attrib_attrs
= sbc_attrib_attrs
,
831 static int __init
iblock_module_init(void)
833 return transport_backend_register(&iblock_ops
);
836 static void __exit
iblock_module_exit(void)
838 target_backend_unregister(&iblock_ops
);
841 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
842 MODULE_AUTHOR("nab@Linux-iSCSI.org");
843 MODULE_LICENSE("GPL");
845 module_init(iblock_module_init
);
846 module_exit(iblock_module_exit
);