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dm table: rework reference counting
[net-next-2.6.git] / drivers / md / dm.c
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1/*
2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"
9#include "dm-bio-list.h"
10#include "dm-uevent.h"
11
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/moduleparam.h>
16#include <linux/blkpg.h>
17#include <linux/bio.h>
18#include <linux/buffer_head.h>
19#include <linux/mempool.h>
20#include <linux/slab.h>
21#include <linux/idr.h>
22#include <linux/hdreg.h>
23#include <linux/blktrace_api.h>
24#include <trace/block.h>
25
26#define DM_MSG_PREFIX "core"
27
28static const char *_name = DM_NAME;
29
30static unsigned int major = 0;
31static unsigned int _major = 0;
32
33static DEFINE_SPINLOCK(_minor_lock);
34/*
35 * For bio-based dm.
36 * One of these is allocated per bio.
37 */
38struct dm_io {
39 struct mapped_device *md;
40 int error;
41 atomic_t io_count;
42 struct bio *bio;
43 unsigned long start_time;
44};
45
46/*
47 * For bio-based dm.
48 * One of these is allocated per target within a bio. Hopefully
49 * this will be simplified out one day.
50 */
51struct dm_target_io {
52 struct dm_io *io;
53 struct dm_target *ti;
54 union map_info info;
55};
56
57DEFINE_TRACE(block_bio_complete);
58
59/*
60 * For request-based dm.
61 * One of these is allocated per request.
62 */
63struct dm_rq_target_io {
64 struct mapped_device *md;
65 struct dm_target *ti;
66 struct request *orig, clone;
67 int error;
68 union map_info info;
69};
70
71/*
72 * For request-based dm.
73 * One of these is allocated per bio.
74 */
75struct dm_rq_clone_bio_info {
76 struct bio *orig;
77 struct request *rq;
78};
79
80union map_info *dm_get_mapinfo(struct bio *bio)
81{
82 if (bio && bio->bi_private)
83 return &((struct dm_target_io *)bio->bi_private)->info;
84 return NULL;
85}
86
87#define MINOR_ALLOCED ((void *)-1)
88
89/*
90 * Bits for the md->flags field.
91 */
92#define DMF_BLOCK_IO 0
93#define DMF_SUSPENDED 1
94#define DMF_FROZEN 2
95#define DMF_FREEING 3
96#define DMF_DELETING 4
97#define DMF_NOFLUSH_SUSPENDING 5
98
99/*
100 * Work processed by per-device workqueue.
101 */
102struct dm_wq_req {
103 enum {
104 DM_WQ_FLUSH_DEFERRED,
105 } type;
106 struct work_struct work;
107 struct mapped_device *md;
108 void *context;
109};
110
111struct mapped_device {
112 struct rw_semaphore io_lock;
113 struct mutex suspend_lock;
114 spinlock_t pushback_lock;
115 rwlock_t map_lock;
116 atomic_t holders;
117 atomic_t open_count;
118
119 unsigned long flags;
120
121 struct request_queue *queue;
122 struct gendisk *disk;
123 char name[16];
124
125 void *interface_ptr;
126
127 /*
128 * A list of ios that arrived while we were suspended.
129 */
130 atomic_t pending;
131 wait_queue_head_t wait;
132 struct bio_list deferred;
133 struct bio_list pushback;
134
135 /*
136 * Processing queue (flush/barriers)
137 */
138 struct workqueue_struct *wq;
139
140 /*
141 * The current mapping.
142 */
143 struct dm_table *map;
144
145 /*
146 * io objects are allocated from here.
147 */
148 mempool_t *io_pool;
149 mempool_t *tio_pool;
150
151 struct bio_set *bs;
152
153 /*
154 * Event handling.
155 */
156 atomic_t event_nr;
157 wait_queue_head_t eventq;
158 atomic_t uevent_seq;
159 struct list_head uevent_list;
160 spinlock_t uevent_lock; /* Protect access to uevent_list */
161
162 /*
163 * freeze/thaw support require holding onto a super block
164 */
165 struct super_block *frozen_sb;
166 struct block_device *suspended_bdev;
167
168 /* forced geometry settings */
169 struct hd_geometry geometry;
170};
171
172#define MIN_IOS 256
173static struct kmem_cache *_io_cache;
174static struct kmem_cache *_tio_cache;
175static struct kmem_cache *_rq_tio_cache;
176static struct kmem_cache *_rq_bio_info_cache;
177
178static int __init local_init(void)
179{
180 int r = -ENOMEM;
181
182 /* allocate a slab for the dm_ios */
183 _io_cache = KMEM_CACHE(dm_io, 0);
184 if (!_io_cache)
185 return r;
186
187 /* allocate a slab for the target ios */
188 _tio_cache = KMEM_CACHE(dm_target_io, 0);
189 if (!_tio_cache)
190 goto out_free_io_cache;
191
192 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
193 if (!_rq_tio_cache)
194 goto out_free_tio_cache;
195
196 _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
197 if (!_rq_bio_info_cache)
198 goto out_free_rq_tio_cache;
199
200 r = dm_uevent_init();
201 if (r)
202 goto out_free_rq_bio_info_cache;
203
204 _major = major;
205 r = register_blkdev(_major, _name);
206 if (r < 0)
207 goto out_uevent_exit;
208
209 if (!_major)
210 _major = r;
211
212 return 0;
213
214out_uevent_exit:
215 dm_uevent_exit();
216out_free_rq_bio_info_cache:
217 kmem_cache_destroy(_rq_bio_info_cache);
218out_free_rq_tio_cache:
219 kmem_cache_destroy(_rq_tio_cache);
220out_free_tio_cache:
221 kmem_cache_destroy(_tio_cache);
222out_free_io_cache:
223 kmem_cache_destroy(_io_cache);
224
225 return r;
226}
227
228static void local_exit(void)
229{
230 kmem_cache_destroy(_rq_bio_info_cache);
231 kmem_cache_destroy(_rq_tio_cache);
232 kmem_cache_destroy(_tio_cache);
233 kmem_cache_destroy(_io_cache);
234 unregister_blkdev(_major, _name);
235 dm_uevent_exit();
236
237 _major = 0;
238
239 DMINFO("cleaned up");
240}
241
242static int (*_inits[])(void) __initdata = {
243 local_init,
244 dm_target_init,
245 dm_linear_init,
246 dm_stripe_init,
247 dm_kcopyd_init,
248 dm_interface_init,
249};
250
251static void (*_exits[])(void) = {
252 local_exit,
253 dm_target_exit,
254 dm_linear_exit,
255 dm_stripe_exit,
256 dm_kcopyd_exit,
257 dm_interface_exit,
258};
259
260static int __init dm_init(void)
261{
262 const int count = ARRAY_SIZE(_inits);
263
264 int r, i;
265
266 for (i = 0; i < count; i++) {
267 r = _inits[i]();
268 if (r)
269 goto bad;
270 }
271
272 return 0;
273
274 bad:
275 while (i--)
276 _exits[i]();
277
278 return r;
279}
280
281static void __exit dm_exit(void)
282{
283 int i = ARRAY_SIZE(_exits);
284
285 while (i--)
286 _exits[i]();
287}
288
289/*
290 * Block device functions
291 */
292static int dm_blk_open(struct block_device *bdev, fmode_t mode)
293{
294 struct mapped_device *md;
295
296 spin_lock(&_minor_lock);
297
298 md = bdev->bd_disk->private_data;
299 if (!md)
300 goto out;
301
302 if (test_bit(DMF_FREEING, &md->flags) ||
303 test_bit(DMF_DELETING, &md->flags)) {
304 md = NULL;
305 goto out;
306 }
307
308 dm_get(md);
309 atomic_inc(&md->open_count);
310
311out:
312 spin_unlock(&_minor_lock);
313
314 return md ? 0 : -ENXIO;
315}
316
317static int dm_blk_close(struct gendisk *disk, fmode_t mode)
318{
319 struct mapped_device *md = disk->private_data;
320 atomic_dec(&md->open_count);
321 dm_put(md);
322 return 0;
323}
324
325int dm_open_count(struct mapped_device *md)
326{
327 return atomic_read(&md->open_count);
328}
329
330/*
331 * Guarantees nothing is using the device before it's deleted.
332 */
333int dm_lock_for_deletion(struct mapped_device *md)
334{
335 int r = 0;
336
337 spin_lock(&_minor_lock);
338
339 if (dm_open_count(md))
340 r = -EBUSY;
341 else
342 set_bit(DMF_DELETING, &md->flags);
343
344 spin_unlock(&_minor_lock);
345
346 return r;
347}
348
349static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
350{
351 struct mapped_device *md = bdev->bd_disk->private_data;
352
353 return dm_get_geometry(md, geo);
354}
355
356static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
357 unsigned int cmd, unsigned long arg)
358{
359 struct mapped_device *md = bdev->bd_disk->private_data;
360 struct dm_table *map = dm_get_table(md);
361 struct dm_target *tgt;
362 int r = -ENOTTY;
363
364 if (!map || !dm_table_get_size(map))
365 goto out;
366
367 /* We only support devices that have a single target */
368 if (dm_table_get_num_targets(map) != 1)
369 goto out;
370
371 tgt = dm_table_get_target(map, 0);
372
373 if (dm_suspended(md)) {
374 r = -EAGAIN;
375 goto out;
376 }
377
378 if (tgt->type->ioctl)
379 r = tgt->type->ioctl(tgt, cmd, arg);
380
381out:
382 dm_table_put(map);
383
384 return r;
385}
386
387static struct dm_io *alloc_io(struct mapped_device *md)
388{
389 return mempool_alloc(md->io_pool, GFP_NOIO);
390}
391
392static void free_io(struct mapped_device *md, struct dm_io *io)
393{
394 mempool_free(io, md->io_pool);
395}
396
397static struct dm_target_io *alloc_tio(struct mapped_device *md)
398{
399 return mempool_alloc(md->tio_pool, GFP_NOIO);
400}
401
402static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
403{
404 mempool_free(tio, md->tio_pool);
405}
406
407static void start_io_acct(struct dm_io *io)
408{
409 struct mapped_device *md = io->md;
410 int cpu;
411
412 io->start_time = jiffies;
413
414 cpu = part_stat_lock();
415 part_round_stats(cpu, &dm_disk(md)->part0);
416 part_stat_unlock();
417 dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending);
418}
419
420static void end_io_acct(struct dm_io *io)
421{
422 struct mapped_device *md = io->md;
423 struct bio *bio = io->bio;
424 unsigned long duration = jiffies - io->start_time;
425 int pending, cpu;
426 int rw = bio_data_dir(bio);
427
428 cpu = part_stat_lock();
429 part_round_stats(cpu, &dm_disk(md)->part0);
430 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
431 part_stat_unlock();
432
433 dm_disk(md)->part0.in_flight = pending =
434 atomic_dec_return(&md->pending);
435
436 /* nudge anyone waiting on suspend queue */
437 if (!pending)
438 wake_up(&md->wait);
439}
440
441/*
442 * Add the bio to the list of deferred io.
443 */
444static int queue_io(struct mapped_device *md, struct bio *bio)
445{
446 down_write(&md->io_lock);
447
448 if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
449 up_write(&md->io_lock);
450 return 1;
451 }
452
453 bio_list_add(&md->deferred, bio);
454
455 up_write(&md->io_lock);
456 return 0; /* deferred successfully */
457}
458
459/*
460 * Everyone (including functions in this file), should use this
461 * function to access the md->map field, and make sure they call
462 * dm_table_put() when finished.
463 */
464struct dm_table *dm_get_table(struct mapped_device *md)
465{
466 struct dm_table *t;
467
468 read_lock(&md->map_lock);
469 t = md->map;
470 if (t)
471 dm_table_get(t);
472 read_unlock(&md->map_lock);
473
474 return t;
475}
476
477/*
478 * Get the geometry associated with a dm device
479 */
480int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
481{
482 *geo = md->geometry;
483
484 return 0;
485}
486
487/*
488 * Set the geometry of a device.
489 */
490int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
491{
492 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
493
494 if (geo->start > sz) {
495 DMWARN("Start sector is beyond the geometry limits.");
496 return -EINVAL;
497 }
498
499 md->geometry = *geo;
500
501 return 0;
502}
503
504/*-----------------------------------------------------------------
505 * CRUD START:
506 * A more elegant soln is in the works that uses the queue
507 * merge fn, unfortunately there are a couple of changes to
508 * the block layer that I want to make for this. So in the
509 * interests of getting something for people to use I give
510 * you this clearly demarcated crap.
511 *---------------------------------------------------------------*/
512
513static int __noflush_suspending(struct mapped_device *md)
514{
515 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
516}
517
518/*
519 * Decrements the number of outstanding ios that a bio has been
520 * cloned into, completing the original io if necc.
521 */
522static void dec_pending(struct dm_io *io, int error)
523{
524 unsigned long flags;
525
526 /* Push-back supersedes any I/O errors */
527 if (error && !(io->error > 0 && __noflush_suspending(io->md)))
528 io->error = error;
529
530 if (atomic_dec_and_test(&io->io_count)) {
531 if (io->error == DM_ENDIO_REQUEUE) {
532 /*
533 * Target requested pushing back the I/O.
534 * This must be handled before the sleeper on
535 * suspend queue merges the pushback list.
536 */
537 spin_lock_irqsave(&io->md->pushback_lock, flags);
538 if (__noflush_suspending(io->md))
539 bio_list_add(&io->md->pushback, io->bio);
540 else
541 /* noflush suspend was interrupted. */
542 io->error = -EIO;
543 spin_unlock_irqrestore(&io->md->pushback_lock, flags);
544 }
545
546 end_io_acct(io);
547
548 if (io->error != DM_ENDIO_REQUEUE) {
549 trace_block_bio_complete(io->md->queue, io->bio);
550
551 bio_endio(io->bio, io->error);
552 }
553
554 free_io(io->md, io);
555 }
556}
557
558static void clone_endio(struct bio *bio, int error)
559{
560 int r = 0;
561 struct dm_target_io *tio = bio->bi_private;
562 struct mapped_device *md = tio->io->md;
563 dm_endio_fn endio = tio->ti->type->end_io;
564
565 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
566 error = -EIO;
567
568 if (endio) {
569 r = endio(tio->ti, bio, error, &tio->info);
570 if (r < 0 || r == DM_ENDIO_REQUEUE)
571 /*
572 * error and requeue request are handled
573 * in dec_pending().
574 */
575 error = r;
576 else if (r == DM_ENDIO_INCOMPLETE)
577 /* The target will handle the io */
578 return;
579 else if (r) {
580 DMWARN("unimplemented target endio return value: %d", r);
581 BUG();
582 }
583 }
584
585 dec_pending(tio->io, error);
586
587 /*
588 * Store md for cleanup instead of tio which is about to get freed.
589 */
590 bio->bi_private = md->bs;
591
592 bio_put(bio);
593 free_tio(md, tio);
594}
595
596static sector_t max_io_len(struct mapped_device *md,
597 sector_t sector, struct dm_target *ti)
598{
599 sector_t offset = sector - ti->begin;
600 sector_t len = ti->len - offset;
601
602 /*
603 * Does the target need to split even further ?
604 */
605 if (ti->split_io) {
606 sector_t boundary;
607 boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
608 - offset;
609 if (len > boundary)
610 len = boundary;
611 }
612
613 return len;
614}
615
616static void __map_bio(struct dm_target *ti, struct bio *clone,
617 struct dm_target_io *tio)
618{
619 int r;
620 sector_t sector;
621 struct mapped_device *md;
622
623 /*
624 * Sanity checks.
625 */
626 BUG_ON(!clone->bi_size);
627
628 clone->bi_end_io = clone_endio;
629 clone->bi_private = tio;
630
631 /*
632 * Map the clone. If r == 0 we don't need to do
633 * anything, the target has assumed ownership of
634 * this io.
635 */
636 atomic_inc(&tio->io->io_count);
637 sector = clone->bi_sector;
638 r = ti->type->map(ti, clone, &tio->info);
639 if (r == DM_MAPIO_REMAPPED) {
640 /* the bio has been remapped so dispatch it */
641
642 trace_block_remap(bdev_get_queue(clone->bi_bdev), clone,
643 tio->io->bio->bi_bdev->bd_dev,
644 clone->bi_sector, sector);
645
646 generic_make_request(clone);
647 } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
648 /* error the io and bail out, or requeue it if needed */
649 md = tio->io->md;
650 dec_pending(tio->io, r);
651 /*
652 * Store bio_set for cleanup.
653 */
654 clone->bi_private = md->bs;
655 bio_put(clone);
656 free_tio(md, tio);
657 } else if (r) {
658 DMWARN("unimplemented target map return value: %d", r);
659 BUG();
660 }
661}
662
663struct clone_info {
664 struct mapped_device *md;
665 struct dm_table *map;
666 struct bio *bio;
667 struct dm_io *io;
668 sector_t sector;
669 sector_t sector_count;
670 unsigned short idx;
671};
672
673static void dm_bio_destructor(struct bio *bio)
674{
675 struct bio_set *bs = bio->bi_private;
676
677 bio_free(bio, bs);
678}
679
680/*
681 * Creates a little bio that is just does part of a bvec.
682 */
683static struct bio *split_bvec(struct bio *bio, sector_t sector,
684 unsigned short idx, unsigned int offset,
685 unsigned int len, struct bio_set *bs)
686{
687 struct bio *clone;
688 struct bio_vec *bv = bio->bi_io_vec + idx;
689
690 clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
691 clone->bi_destructor = dm_bio_destructor;
692 *clone->bi_io_vec = *bv;
693
694 clone->bi_sector = sector;
695 clone->bi_bdev = bio->bi_bdev;
696 clone->bi_rw = bio->bi_rw;
697 clone->bi_vcnt = 1;
698 clone->bi_size = to_bytes(len);
699 clone->bi_io_vec->bv_offset = offset;
700 clone->bi_io_vec->bv_len = clone->bi_size;
701 clone->bi_flags |= 1 << BIO_CLONED;
702
703 return clone;
704}
705
706/*
707 * Creates a bio that consists of range of complete bvecs.
708 */
709static struct bio *clone_bio(struct bio *bio, sector_t sector,
710 unsigned short idx, unsigned short bv_count,
711 unsigned int len, struct bio_set *bs)
712{
713 struct bio *clone;
714
715 clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
716 __bio_clone(clone, bio);
717 clone->bi_destructor = dm_bio_destructor;
718 clone->bi_sector = sector;
719 clone->bi_idx = idx;
720 clone->bi_vcnt = idx + bv_count;
721 clone->bi_size = to_bytes(len);
722 clone->bi_flags &= ~(1 << BIO_SEG_VALID);
723
724 return clone;
725}
726
727static int __clone_and_map(struct clone_info *ci)
728{
729 struct bio *clone, *bio = ci->bio;
730 struct dm_target *ti;
731 sector_t len = 0, max;
732 struct dm_target_io *tio;
733
734 ti = dm_table_find_target(ci->map, ci->sector);
735 if (!dm_target_is_valid(ti))
736 return -EIO;
737
738 max = max_io_len(ci->md, ci->sector, ti);
739
740 /*
741 * Allocate a target io object.
742 */
743 tio = alloc_tio(ci->md);
744 tio->io = ci->io;
745 tio->ti = ti;
746 memset(&tio->info, 0, sizeof(tio->info));
747
748 if (ci->sector_count <= max) {
749 /*
750 * Optimise for the simple case where we can do all of
751 * the remaining io with a single clone.
752 */
753 clone = clone_bio(bio, ci->sector, ci->idx,
754 bio->bi_vcnt - ci->idx, ci->sector_count,
755 ci->md->bs);
756 __map_bio(ti, clone, tio);
757 ci->sector_count = 0;
758
759 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
760 /*
761 * There are some bvecs that don't span targets.
762 * Do as many of these as possible.
763 */
764 int i;
765 sector_t remaining = max;
766 sector_t bv_len;
767
768 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
769 bv_len = to_sector(bio->bi_io_vec[i].bv_len);
770
771 if (bv_len > remaining)
772 break;
773
774 remaining -= bv_len;
775 len += bv_len;
776 }
777
778 clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
779 ci->md->bs);
780 __map_bio(ti, clone, tio);
781
782 ci->sector += len;
783 ci->sector_count -= len;
784 ci->idx = i;
785
786 } else {
787 /*
788 * Handle a bvec that must be split between two or more targets.
789 */
790 struct bio_vec *bv = bio->bi_io_vec + ci->idx;
791 sector_t remaining = to_sector(bv->bv_len);
792 unsigned int offset = 0;
793
794 do {
795 if (offset) {
796 ti = dm_table_find_target(ci->map, ci->sector);
797 if (!dm_target_is_valid(ti))
798 return -EIO;
799
800 max = max_io_len(ci->md, ci->sector, ti);
801
802 tio = alloc_tio(ci->md);
803 tio->io = ci->io;
804 tio->ti = ti;
805 memset(&tio->info, 0, sizeof(tio->info));
806 }
807
808 len = min(remaining, max);
809
810 clone = split_bvec(bio, ci->sector, ci->idx,
811 bv->bv_offset + offset, len,
812 ci->md->bs);
813
814 __map_bio(ti, clone, tio);
815
816 ci->sector += len;
817 ci->sector_count -= len;
818 offset += to_bytes(len);
819 } while (remaining -= len);
820
821 ci->idx++;
822 }
823
824 return 0;
825}
826
827/*
828 * Split the bio into several clones.
829 */
830static int __split_bio(struct mapped_device *md, struct bio *bio)
831{
832 struct clone_info ci;
833 int error = 0;
834
835 ci.map = dm_get_table(md);
836 if (unlikely(!ci.map))
837 return -EIO;
838 if (unlikely(bio_barrier(bio) && !dm_table_barrier_ok(ci.map))) {
839 dm_table_put(ci.map);
840 bio_endio(bio, -EOPNOTSUPP);
841 return 0;
842 }
843 ci.md = md;
844 ci.bio = bio;
845 ci.io = alloc_io(md);
846 ci.io->error = 0;
847 atomic_set(&ci.io->io_count, 1);
848 ci.io->bio = bio;
849 ci.io->md = md;
850 ci.sector = bio->bi_sector;
851 ci.sector_count = bio_sectors(bio);
852 ci.idx = bio->bi_idx;
853
854 start_io_acct(ci.io);
855 while (ci.sector_count && !error)
856 error = __clone_and_map(&ci);
857
858 /* drop the extra reference count */
859 dec_pending(ci.io, error);
860 dm_table_put(ci.map);
861
862 return 0;
863}
864/*-----------------------------------------------------------------
865 * CRUD END
866 *---------------------------------------------------------------*/
867
868static int dm_merge_bvec(struct request_queue *q,
869 struct bvec_merge_data *bvm,
870 struct bio_vec *biovec)
871{
872 struct mapped_device *md = q->queuedata;
873 struct dm_table *map = dm_get_table(md);
874 struct dm_target *ti;
875 sector_t max_sectors;
876 int max_size = 0;
877
878 if (unlikely(!map))
879 goto out;
880
881 ti = dm_table_find_target(map, bvm->bi_sector);
882 if (!dm_target_is_valid(ti))
883 goto out_table;
884
885 /*
886 * Find maximum amount of I/O that won't need splitting
887 */
888 max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
889 (sector_t) BIO_MAX_SECTORS);
890 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
891 if (max_size < 0)
892 max_size = 0;
893
894 /*
895 * merge_bvec_fn() returns number of bytes
896 * it can accept at this offset
897 * max is precomputed maximal io size
898 */
899 if (max_size && ti->type->merge)
900 max_size = ti->type->merge(ti, bvm, biovec, max_size);
901
902out_table:
903 dm_table_put(map);
904
905out:
906 /*
907 * Always allow an entire first page
908 */
909 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
910 max_size = biovec->bv_len;
911
912 return max_size;
913}
914
915/*
916 * The request function that just remaps the bio built up by
917 * dm_merge_bvec.
918 */
919static int dm_request(struct request_queue *q, struct bio *bio)
920{
921 int r = -EIO;
922 int rw = bio_data_dir(bio);
923 struct mapped_device *md = q->queuedata;
924 int cpu;
925
926 down_read(&md->io_lock);
927
928 cpu = part_stat_lock();
929 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
930 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
931 part_stat_unlock();
932
933 /*
934 * If we're suspended we have to queue
935 * this io for later.
936 */
937 while (test_bit(DMF_BLOCK_IO, &md->flags)) {
938 up_read(&md->io_lock);
939
940 if (bio_rw(bio) != READA)
941 r = queue_io(md, bio);
942
943 if (r <= 0)
944 goto out_req;
945
946 /*
947 * We're in a while loop, because someone could suspend
948 * before we get to the following read lock.
949 */
950 down_read(&md->io_lock);
951 }
952
953 r = __split_bio(md, bio);
954 up_read(&md->io_lock);
955
956out_req:
957 if (r < 0)
958 bio_io_error(bio);
959
960 return 0;
961}
962
963static void dm_unplug_all(struct request_queue *q)
964{
965 struct mapped_device *md = q->queuedata;
966 struct dm_table *map = dm_get_table(md);
967
968 if (map) {
969 dm_table_unplug_all(map);
970 dm_table_put(map);
971 }
972}
973
974static int dm_any_congested(void *congested_data, int bdi_bits)
975{
976 int r = bdi_bits;
977 struct mapped_device *md = congested_data;
978 struct dm_table *map;
979
980 if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
981 map = dm_get_table(md);
982 if (map) {
983 r = dm_table_any_congested(map, bdi_bits);
984 dm_table_put(map);
985 }
986 }
987
988 return r;
989}
990
991/*-----------------------------------------------------------------
992 * An IDR is used to keep track of allocated minor numbers.
993 *---------------------------------------------------------------*/
994static DEFINE_IDR(_minor_idr);
995
996static void free_minor(int minor)
997{
998 spin_lock(&_minor_lock);
999 idr_remove(&_minor_idr, minor);
1000 spin_unlock(&_minor_lock);
1001}
1002
1003/*
1004 * See if the device with a specific minor # is free.
1005 */
1006static int specific_minor(int minor)
1007{
1008 int r, m;
1009
1010 if (minor >= (1 << MINORBITS))
1011 return -EINVAL;
1012
1013 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1014 if (!r)
1015 return -ENOMEM;
1016
1017 spin_lock(&_minor_lock);
1018
1019 if (idr_find(&_minor_idr, minor)) {
1020 r = -EBUSY;
1021 goto out;
1022 }
1023
1024 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
1025 if (r)
1026 goto out;
1027
1028 if (m != minor) {
1029 idr_remove(&_minor_idr, m);
1030 r = -EBUSY;
1031 goto out;
1032 }
1033
1034out:
1035 spin_unlock(&_minor_lock);
1036 return r;
1037}
1038
1039static int next_free_minor(int *minor)
1040{
1041 int r, m;
1042
1043 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1044 if (!r)
1045 return -ENOMEM;
1046
1047 spin_lock(&_minor_lock);
1048
1049 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
1050 if (r)
1051 goto out;
1052
1053 if (m >= (1 << MINORBITS)) {
1054 idr_remove(&_minor_idr, m);
1055 r = -ENOSPC;
1056 goto out;
1057 }
1058
1059 *minor = m;
1060
1061out:
1062 spin_unlock(&_minor_lock);
1063 return r;
1064}
1065
1066static struct block_device_operations dm_blk_dops;
1067
1068/*
1069 * Allocate and initialise a blank device with a given minor.
1070 */
1071static struct mapped_device *alloc_dev(int minor)
1072{
1073 int r;
1074 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
1075 void *old_md;
1076
1077 if (!md) {
1078 DMWARN("unable to allocate device, out of memory.");
1079 return NULL;
1080 }
1081
1082 if (!try_module_get(THIS_MODULE))
1083 goto bad_module_get;
1084
1085 /* get a minor number for the dev */
1086 if (minor == DM_ANY_MINOR)
1087 r = next_free_minor(&minor);
1088 else
1089 r = specific_minor(minor);
1090 if (r < 0)
1091 goto bad_minor;
1092
1093 init_rwsem(&md->io_lock);
1094 mutex_init(&md->suspend_lock);
1095 spin_lock_init(&md->pushback_lock);
1096 rwlock_init(&md->map_lock);
1097 atomic_set(&md->holders, 1);
1098 atomic_set(&md->open_count, 0);
1099 atomic_set(&md->event_nr, 0);
1100 atomic_set(&md->uevent_seq, 0);
1101 INIT_LIST_HEAD(&md->uevent_list);
1102 spin_lock_init(&md->uevent_lock);
1103
1104 md->queue = blk_alloc_queue(GFP_KERNEL);
1105 if (!md->queue)
1106 goto bad_queue;
1107
1108 md->queue->queuedata = md;
1109 md->queue->backing_dev_info.congested_fn = dm_any_congested;
1110 md->queue->backing_dev_info.congested_data = md;
1111 blk_queue_make_request(md->queue, dm_request);
1112 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
1113 md->queue->unplug_fn = dm_unplug_all;
1114 blk_queue_merge_bvec(md->queue, dm_merge_bvec);
1115
1116 md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
1117 if (!md->io_pool)
1118 goto bad_io_pool;
1119
1120 md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
1121 if (!md->tio_pool)
1122 goto bad_tio_pool;
1123
1124 md->bs = bioset_create(16, 0);
1125 if (!md->bs)
1126 goto bad_no_bioset;
1127
1128 md->disk = alloc_disk(1);
1129 if (!md->disk)
1130 goto bad_disk;
1131
1132 atomic_set(&md->pending, 0);
1133 init_waitqueue_head(&md->wait);
1134 init_waitqueue_head(&md->eventq);
1135
1136 md->disk->major = _major;
1137 md->disk->first_minor = minor;
1138 md->disk->fops = &dm_blk_dops;
1139 md->disk->queue = md->queue;
1140 md->disk->private_data = md;
1141 sprintf(md->disk->disk_name, "dm-%d", minor);
1142 add_disk(md->disk);
1143 format_dev_t(md->name, MKDEV(_major, minor));
1144
1145 md->wq = create_singlethread_workqueue("kdmflush");
1146 if (!md->wq)
1147 goto bad_thread;
1148
1149 /* Populate the mapping, nobody knows we exist yet */
1150 spin_lock(&_minor_lock);
1151 old_md = idr_replace(&_minor_idr, md, minor);
1152 spin_unlock(&_minor_lock);
1153
1154 BUG_ON(old_md != MINOR_ALLOCED);
1155
1156 return md;
1157
1158bad_thread:
1159 put_disk(md->disk);
1160bad_disk:
1161 bioset_free(md->bs);
1162bad_no_bioset:
1163 mempool_destroy(md->tio_pool);
1164bad_tio_pool:
1165 mempool_destroy(md->io_pool);
1166bad_io_pool:
1167 blk_cleanup_queue(md->queue);
1168bad_queue:
1169 free_minor(minor);
1170bad_minor:
1171 module_put(THIS_MODULE);
1172bad_module_get:
1173 kfree(md);
1174 return NULL;
1175}
1176
1177static void unlock_fs(struct mapped_device *md);
1178
1179static void free_dev(struct mapped_device *md)
1180{
1181 int minor = MINOR(disk_devt(md->disk));
1182
1183 if (md->suspended_bdev) {
1184 unlock_fs(md);
1185 bdput(md->suspended_bdev);
1186 }
1187 destroy_workqueue(md->wq);
1188 mempool_destroy(md->tio_pool);
1189 mempool_destroy(md->io_pool);
1190 bioset_free(md->bs);
1191 del_gendisk(md->disk);
1192 free_minor(minor);
1193
1194 spin_lock(&_minor_lock);
1195 md->disk->private_data = NULL;
1196 spin_unlock(&_minor_lock);
1197
1198 put_disk(md->disk);
1199 blk_cleanup_queue(md->queue);
1200 module_put(THIS_MODULE);
1201 kfree(md);
1202}
1203
1204/*
1205 * Bind a table to the device.
1206 */
1207static void event_callback(void *context)
1208{
1209 unsigned long flags;
1210 LIST_HEAD(uevents);
1211 struct mapped_device *md = (struct mapped_device *) context;
1212
1213 spin_lock_irqsave(&md->uevent_lock, flags);
1214 list_splice_init(&md->uevent_list, &uevents);
1215 spin_unlock_irqrestore(&md->uevent_lock, flags);
1216
1217 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
1218
1219 atomic_inc(&md->event_nr);
1220 wake_up(&md->eventq);
1221}
1222
1223static void __set_size(struct mapped_device *md, sector_t size)
1224{
1225 set_capacity(md->disk, size);
1226
1227 mutex_lock(&md->suspended_bdev->bd_inode->i_mutex);
1228 i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
1229 mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex);
1230}
1231
1232static int __bind(struct mapped_device *md, struct dm_table *t)
1233{
1234 struct request_queue *q = md->queue;
1235 sector_t size;
1236
1237 size = dm_table_get_size(t);
1238
1239 /*
1240 * Wipe any geometry if the size of the table changed.
1241 */
1242 if (size != get_capacity(md->disk))
1243 memset(&md->geometry, 0, sizeof(md->geometry));
1244
1245 if (md->suspended_bdev)
1246 __set_size(md, size);
1247
1248 if (!size) {
1249 dm_table_destroy(t);
1250 return 0;
1251 }
1252
1253 dm_table_event_callback(t, event_callback, md);
1254
1255 write_lock(&md->map_lock);
1256 md->map = t;
1257 dm_table_set_restrictions(t, q);
1258 write_unlock(&md->map_lock);
1259
1260 return 0;
1261}
1262
1263static void __unbind(struct mapped_device *md)
1264{
1265 struct dm_table *map = md->map;
1266
1267 if (!map)
1268 return;
1269
1270 dm_table_event_callback(map, NULL, NULL);
1271 write_lock(&md->map_lock);
1272 md->map = NULL;
1273 write_unlock(&md->map_lock);
1274 dm_table_destroy(map);
1275}
1276
1277/*
1278 * Constructor for a new device.
1279 */
1280int dm_create(int minor, struct mapped_device **result)
1281{
1282 struct mapped_device *md;
1283
1284 md = alloc_dev(minor);
1285 if (!md)
1286 return -ENXIO;
1287
1288 *result = md;
1289 return 0;
1290}
1291
1292static struct mapped_device *dm_find_md(dev_t dev)
1293{
1294 struct mapped_device *md;
1295 unsigned minor = MINOR(dev);
1296
1297 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
1298 return NULL;
1299
1300 spin_lock(&_minor_lock);
1301
1302 md = idr_find(&_minor_idr, minor);
1303 if (md && (md == MINOR_ALLOCED ||
1304 (MINOR(disk_devt(dm_disk(md))) != minor) ||
1305 test_bit(DMF_FREEING, &md->flags))) {
1306 md = NULL;
1307 goto out;
1308 }
1309
1310out:
1311 spin_unlock(&_minor_lock);
1312
1313 return md;
1314}
1315
1316struct mapped_device *dm_get_md(dev_t dev)
1317{
1318 struct mapped_device *md = dm_find_md(dev);
1319
1320 if (md)
1321 dm_get(md);
1322
1323 return md;
1324}
1325
1326void *dm_get_mdptr(struct mapped_device *md)
1327{
1328 return md->interface_ptr;
1329}
1330
1331void dm_set_mdptr(struct mapped_device *md, void *ptr)
1332{
1333 md->interface_ptr = ptr;
1334}
1335
1336void dm_get(struct mapped_device *md)
1337{
1338 atomic_inc(&md->holders);
1339}
1340
1341const char *dm_device_name(struct mapped_device *md)
1342{
1343 return md->name;
1344}
1345EXPORT_SYMBOL_GPL(dm_device_name);
1346
1347void dm_put(struct mapped_device *md)
1348{
1349 struct dm_table *map;
1350
1351 BUG_ON(test_bit(DMF_FREEING, &md->flags));
1352
1353 if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
1354 map = dm_get_table(md);
1355 idr_replace(&_minor_idr, MINOR_ALLOCED,
1356 MINOR(disk_devt(dm_disk(md))));
1357 set_bit(DMF_FREEING, &md->flags);
1358 spin_unlock(&_minor_lock);
1359 if (!dm_suspended(md)) {
1360 dm_table_presuspend_targets(map);
1361 dm_table_postsuspend_targets(map);
1362 }
1363 dm_table_put(map);
1364 __unbind(md);
1365 free_dev(md);
1366 }
1367}
1368EXPORT_SYMBOL_GPL(dm_put);
1369
1370static int dm_wait_for_completion(struct mapped_device *md)
1371{
1372 int r = 0;
1373
1374 while (1) {
1375 set_current_state(TASK_INTERRUPTIBLE);
1376
1377 smp_mb();
1378 if (!atomic_read(&md->pending))
1379 break;
1380
1381 if (signal_pending(current)) {
1382 r = -EINTR;
1383 break;
1384 }
1385
1386 io_schedule();
1387 }
1388 set_current_state(TASK_RUNNING);
1389
1390 return r;
1391}
1392
1393/*
1394 * Process the deferred bios
1395 */
1396static void __flush_deferred_io(struct mapped_device *md)
1397{
1398 struct bio *c;
1399
1400 while ((c = bio_list_pop(&md->deferred))) {
1401 if (__split_bio(md, c))
1402 bio_io_error(c);
1403 }
1404
1405 clear_bit(DMF_BLOCK_IO, &md->flags);
1406}
1407
1408static void __merge_pushback_list(struct mapped_device *md)
1409{
1410 unsigned long flags;
1411
1412 spin_lock_irqsave(&md->pushback_lock, flags);
1413 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
1414 bio_list_merge_head(&md->deferred, &md->pushback);
1415 bio_list_init(&md->pushback);
1416 spin_unlock_irqrestore(&md->pushback_lock, flags);
1417}
1418
1419static void dm_wq_work(struct work_struct *work)
1420{
1421 struct dm_wq_req *req = container_of(work, struct dm_wq_req, work);
1422 struct mapped_device *md = req->md;
1423
1424 down_write(&md->io_lock);
1425 switch (req->type) {
1426 case DM_WQ_FLUSH_DEFERRED:
1427 __flush_deferred_io(md);
1428 break;
1429 default:
1430 DMERR("dm_wq_work: unrecognised work type %d", req->type);
1431 BUG();
1432 }
1433 up_write(&md->io_lock);
1434}
1435
1436static void dm_wq_queue(struct mapped_device *md, int type, void *context,
1437 struct dm_wq_req *req)
1438{
1439 req->type = type;
1440 req->md = md;
1441 req->context = context;
1442 INIT_WORK(&req->work, dm_wq_work);
1443 queue_work(md->wq, &req->work);
1444}
1445
1446static void dm_queue_flush(struct mapped_device *md, int type, void *context)
1447{
1448 struct dm_wq_req req;
1449
1450 dm_wq_queue(md, type, context, &req);
1451 flush_workqueue(md->wq);
1452}
1453
1454/*
1455 * Swap in a new table (destroying old one).
1456 */
1457int dm_swap_table(struct mapped_device *md, struct dm_table *table)
1458{
1459 int r = -EINVAL;
1460
1461 mutex_lock(&md->suspend_lock);
1462
1463 /* device must be suspended */
1464 if (!dm_suspended(md))
1465 goto out;
1466
1467 /* without bdev, the device size cannot be changed */
1468 if (!md->suspended_bdev)
1469 if (get_capacity(md->disk) != dm_table_get_size(table))
1470 goto out;
1471
1472 __unbind(md);
1473 r = __bind(md, table);
1474
1475out:
1476 mutex_unlock(&md->suspend_lock);
1477 return r;
1478}
1479
1480/*
1481 * Functions to lock and unlock any filesystem running on the
1482 * device.
1483 */
1484static int lock_fs(struct mapped_device *md)
1485{
1486 int r;
1487
1488 WARN_ON(md->frozen_sb);
1489
1490 md->frozen_sb = freeze_bdev(md->suspended_bdev);
1491 if (IS_ERR(md->frozen_sb)) {
1492 r = PTR_ERR(md->frozen_sb);
1493 md->frozen_sb = NULL;
1494 return r;
1495 }
1496
1497 set_bit(DMF_FROZEN, &md->flags);
1498
1499 /* don't bdput right now, we don't want the bdev
1500 * to go away while it is locked.
1501 */
1502 return 0;
1503}
1504
1505static void unlock_fs(struct mapped_device *md)
1506{
1507 if (!test_bit(DMF_FROZEN, &md->flags))
1508 return;
1509
1510 thaw_bdev(md->suspended_bdev, md->frozen_sb);
1511 md->frozen_sb = NULL;
1512 clear_bit(DMF_FROZEN, &md->flags);
1513}
1514
1515/*
1516 * We need to be able to change a mapping table under a mounted
1517 * filesystem. For example we might want to move some data in
1518 * the background. Before the table can be swapped with
1519 * dm_bind_table, dm_suspend must be called to flush any in
1520 * flight bios and ensure that any further io gets deferred.
1521 */
1522int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
1523{
1524 struct dm_table *map = NULL;
1525 DECLARE_WAITQUEUE(wait, current);
1526 int r = 0;
1527 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
1528 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
1529
1530 mutex_lock(&md->suspend_lock);
1531
1532 if (dm_suspended(md)) {
1533 r = -EINVAL;
1534 goto out_unlock;
1535 }
1536
1537 map = dm_get_table(md);
1538
1539 /*
1540 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
1541 * This flag is cleared before dm_suspend returns.
1542 */
1543 if (noflush)
1544 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
1545
1546 /* This does not get reverted if there's an error later. */
1547 dm_table_presuspend_targets(map);
1548
1549 /* bdget() can stall if the pending I/Os are not flushed */
1550 if (!noflush) {
1551 md->suspended_bdev = bdget_disk(md->disk, 0);
1552 if (!md->suspended_bdev) {
1553 DMWARN("bdget failed in dm_suspend");
1554 r = -ENOMEM;
1555 goto out;
1556 }
1557
1558 /*
1559 * Flush I/O to the device. noflush supersedes do_lockfs,
1560 * because lock_fs() needs to flush I/Os.
1561 */
1562 if (do_lockfs) {
1563 r = lock_fs(md);
1564 if (r)
1565 goto out;
1566 }
1567 }
1568
1569 /*
1570 * First we set the BLOCK_IO flag so no more ios will be mapped.
1571 */
1572 down_write(&md->io_lock);
1573 set_bit(DMF_BLOCK_IO, &md->flags);
1574
1575 add_wait_queue(&md->wait, &wait);
1576 up_write(&md->io_lock);
1577
1578 /* unplug */
1579 if (map)
1580 dm_table_unplug_all(map);
1581
1582 /*
1583 * Wait for the already-mapped ios to complete.
1584 */
1585 r = dm_wait_for_completion(md);
1586
1587 down_write(&md->io_lock);
1588 remove_wait_queue(&md->wait, &wait);
1589
1590 if (noflush)
1591 __merge_pushback_list(md);
1592 up_write(&md->io_lock);
1593
1594 /* were we interrupted ? */
1595 if (r < 0) {
1596 dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
1597
1598 unlock_fs(md);
1599 goto out; /* pushback list is already flushed, so skip flush */
1600 }
1601
1602 dm_table_postsuspend_targets(map);
1603
1604 set_bit(DMF_SUSPENDED, &md->flags);
1605
1606out:
1607 if (r && md->suspended_bdev) {
1608 bdput(md->suspended_bdev);
1609 md->suspended_bdev = NULL;
1610 }
1611
1612 dm_table_put(map);
1613
1614out_unlock:
1615 mutex_unlock(&md->suspend_lock);
1616 return r;
1617}
1618
1619int dm_resume(struct mapped_device *md)
1620{
1621 int r = -EINVAL;
1622 struct dm_table *map = NULL;
1623
1624 mutex_lock(&md->suspend_lock);
1625 if (!dm_suspended(md))
1626 goto out;
1627
1628 map = dm_get_table(md);
1629 if (!map || !dm_table_get_size(map))
1630 goto out;
1631
1632 r = dm_table_resume_targets(map);
1633 if (r)
1634 goto out;
1635
1636 dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
1637
1638 unlock_fs(md);
1639
1640 if (md->suspended_bdev) {
1641 bdput(md->suspended_bdev);
1642 md->suspended_bdev = NULL;
1643 }
1644
1645 clear_bit(DMF_SUSPENDED, &md->flags);
1646
1647 dm_table_unplug_all(map);
1648
1649 dm_kobject_uevent(md);
1650
1651 r = 0;
1652
1653out:
1654 dm_table_put(map);
1655 mutex_unlock(&md->suspend_lock);
1656
1657 return r;
1658}
1659
1660/*-----------------------------------------------------------------
1661 * Event notification.
1662 *---------------------------------------------------------------*/
1663void dm_kobject_uevent(struct mapped_device *md)
1664{
1665 kobject_uevent(&disk_to_dev(md->disk)->kobj, KOBJ_CHANGE);
1666}
1667
1668uint32_t dm_next_uevent_seq(struct mapped_device *md)
1669{
1670 return atomic_add_return(1, &md->uevent_seq);
1671}
1672
1673uint32_t dm_get_event_nr(struct mapped_device *md)
1674{
1675 return atomic_read(&md->event_nr);
1676}
1677
1678int dm_wait_event(struct mapped_device *md, int event_nr)
1679{
1680 return wait_event_interruptible(md->eventq,
1681 (event_nr != atomic_read(&md->event_nr)));
1682}
1683
1684void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
1685{
1686 unsigned long flags;
1687
1688 spin_lock_irqsave(&md->uevent_lock, flags);
1689 list_add(elist, &md->uevent_list);
1690 spin_unlock_irqrestore(&md->uevent_lock, flags);
1691}
1692
1693/*
1694 * The gendisk is only valid as long as you have a reference
1695 * count on 'md'.
1696 */
1697struct gendisk *dm_disk(struct mapped_device *md)
1698{
1699 return md->disk;
1700}
1701
1702int dm_suspended(struct mapped_device *md)
1703{
1704 return test_bit(DMF_SUSPENDED, &md->flags);
1705}
1706
1707int dm_noflush_suspending(struct dm_target *ti)
1708{
1709 struct mapped_device *md = dm_table_get_md(ti->table);
1710 int r = __noflush_suspending(md);
1711
1712 dm_put(md);
1713
1714 return r;
1715}
1716EXPORT_SYMBOL_GPL(dm_noflush_suspending);
1717
1718static struct block_device_operations dm_blk_dops = {
1719 .open = dm_blk_open,
1720 .release = dm_blk_close,
1721 .ioctl = dm_blk_ioctl,
1722 .getgeo = dm_blk_getgeo,
1723 .owner = THIS_MODULE
1724};
1725
1726EXPORT_SYMBOL(dm_get_mapinfo);
1727
1728/*
1729 * module hooks
1730 */
1731module_init(dm_init);
1732module_exit(dm_exit);
1733
1734module_param(major, uint, 0);
1735MODULE_PARM_DESC(major, "The major number of the device mapper");
1736MODULE_DESCRIPTION(DM_NAME " driver");
1737MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
1738MODULE_LICENSE("GPL");
Clone of davem's net-next-2.6 tree