Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. | |
3 | * Copyright (C) 2004 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 | ||
11 | #include <linux/init.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/moduleparam.h> | |
14 | #include <linux/blkpg.h> | |
15 | #include <linux/bio.h> | |
16 | #include <linux/buffer_head.h> | |
17 | #include <linux/mempool.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/idr.h> | |
2056a782 | 20 | #include <linux/blktrace_api.h> |
1da177e4 LT |
21 | |
22 | static const char *_name = DM_NAME; | |
23 | ||
24 | static unsigned int major = 0; | |
25 | static unsigned int _major = 0; | |
26 | ||
27 | /* | |
28 | * One of these is allocated per bio. | |
29 | */ | |
30 | struct dm_io { | |
31 | struct mapped_device *md; | |
32 | int error; | |
33 | struct bio *bio; | |
34 | atomic_t io_count; | |
3eaf840e | 35 | unsigned long start_time; |
1da177e4 LT |
36 | }; |
37 | ||
38 | /* | |
39 | * One of these is allocated per target within a bio. Hopefully | |
40 | * this will be simplified out one day. | |
41 | */ | |
42 | struct target_io { | |
43 | struct dm_io *io; | |
44 | struct dm_target *ti; | |
45 | union map_info info; | |
46 | }; | |
47 | ||
48 | union map_info *dm_get_mapinfo(struct bio *bio) | |
49 | { | |
50 | if (bio && bio->bi_private) | |
51 | return &((struct target_io *)bio->bi_private)->info; | |
52 | return NULL; | |
53 | } | |
54 | ||
55 | /* | |
56 | * Bits for the md->flags field. | |
57 | */ | |
58 | #define DMF_BLOCK_IO 0 | |
59 | #define DMF_SUSPENDED 1 | |
aa8d7c2f | 60 | #define DMF_FROZEN 2 |
1da177e4 LT |
61 | |
62 | struct mapped_device { | |
2ca3310e AK |
63 | struct rw_semaphore io_lock; |
64 | struct semaphore suspend_lock; | |
1da177e4 LT |
65 | rwlock_t map_lock; |
66 | atomic_t holders; | |
67 | ||
68 | unsigned long flags; | |
69 | ||
70 | request_queue_t *queue; | |
71 | struct gendisk *disk; | |
7e51f257 | 72 | char name[16]; |
1da177e4 LT |
73 | |
74 | void *interface_ptr; | |
75 | ||
76 | /* | |
77 | * A list of ios that arrived while we were suspended. | |
78 | */ | |
79 | atomic_t pending; | |
80 | wait_queue_head_t wait; | |
81 | struct bio_list deferred; | |
82 | ||
83 | /* | |
84 | * The current mapping. | |
85 | */ | |
86 | struct dm_table *map; | |
87 | ||
88 | /* | |
89 | * io objects are allocated from here. | |
90 | */ | |
91 | mempool_t *io_pool; | |
92 | mempool_t *tio_pool; | |
93 | ||
94 | /* | |
95 | * Event handling. | |
96 | */ | |
97 | atomic_t event_nr; | |
98 | wait_queue_head_t eventq; | |
99 | ||
100 | /* | |
101 | * freeze/thaw support require holding onto a super block | |
102 | */ | |
103 | struct super_block *frozen_sb; | |
e39e2e95 | 104 | struct block_device *suspended_bdev; |
1da177e4 LT |
105 | }; |
106 | ||
107 | #define MIN_IOS 256 | |
108 | static kmem_cache_t *_io_cache; | |
109 | static kmem_cache_t *_tio_cache; | |
110 | ||
111 | static struct bio_set *dm_set; | |
112 | ||
113 | static int __init local_init(void) | |
114 | { | |
115 | int r; | |
116 | ||
117 | dm_set = bioset_create(16, 16, 4); | |
118 | if (!dm_set) | |
119 | return -ENOMEM; | |
120 | ||
121 | /* allocate a slab for the dm_ios */ | |
122 | _io_cache = kmem_cache_create("dm_io", | |
123 | sizeof(struct dm_io), 0, 0, NULL, NULL); | |
124 | if (!_io_cache) | |
125 | return -ENOMEM; | |
126 | ||
127 | /* allocate a slab for the target ios */ | |
128 | _tio_cache = kmem_cache_create("dm_tio", sizeof(struct target_io), | |
129 | 0, 0, NULL, NULL); | |
130 | if (!_tio_cache) { | |
131 | kmem_cache_destroy(_io_cache); | |
132 | return -ENOMEM; | |
133 | } | |
134 | ||
135 | _major = major; | |
136 | r = register_blkdev(_major, _name); | |
137 | if (r < 0) { | |
138 | kmem_cache_destroy(_tio_cache); | |
139 | kmem_cache_destroy(_io_cache); | |
140 | return r; | |
141 | } | |
142 | ||
143 | if (!_major) | |
144 | _major = r; | |
145 | ||
146 | return 0; | |
147 | } | |
148 | ||
149 | static void local_exit(void) | |
150 | { | |
151 | kmem_cache_destroy(_tio_cache); | |
152 | kmem_cache_destroy(_io_cache); | |
153 | ||
154 | bioset_free(dm_set); | |
155 | ||
156 | if (unregister_blkdev(_major, _name) < 0) | |
157 | DMERR("devfs_unregister_blkdev failed"); | |
158 | ||
159 | _major = 0; | |
160 | ||
161 | DMINFO("cleaned up"); | |
162 | } | |
163 | ||
164 | int (*_inits[])(void) __initdata = { | |
165 | local_init, | |
166 | dm_target_init, | |
167 | dm_linear_init, | |
168 | dm_stripe_init, | |
169 | dm_interface_init, | |
170 | }; | |
171 | ||
172 | void (*_exits[])(void) = { | |
173 | local_exit, | |
174 | dm_target_exit, | |
175 | dm_linear_exit, | |
176 | dm_stripe_exit, | |
177 | dm_interface_exit, | |
178 | }; | |
179 | ||
180 | static int __init dm_init(void) | |
181 | { | |
182 | const int count = ARRAY_SIZE(_inits); | |
183 | ||
184 | int r, i; | |
185 | ||
186 | for (i = 0; i < count; i++) { | |
187 | r = _inits[i](); | |
188 | if (r) | |
189 | goto bad; | |
190 | } | |
191 | ||
192 | return 0; | |
193 | ||
194 | bad: | |
195 | while (i--) | |
196 | _exits[i](); | |
197 | ||
198 | return r; | |
199 | } | |
200 | ||
201 | static void __exit dm_exit(void) | |
202 | { | |
203 | int i = ARRAY_SIZE(_exits); | |
204 | ||
205 | while (i--) | |
206 | _exits[i](); | |
207 | } | |
208 | ||
209 | /* | |
210 | * Block device functions | |
211 | */ | |
212 | static int dm_blk_open(struct inode *inode, struct file *file) | |
213 | { | |
214 | struct mapped_device *md; | |
215 | ||
216 | md = inode->i_bdev->bd_disk->private_data; | |
217 | dm_get(md); | |
218 | return 0; | |
219 | } | |
220 | ||
221 | static int dm_blk_close(struct inode *inode, struct file *file) | |
222 | { | |
223 | struct mapped_device *md; | |
224 | ||
225 | md = inode->i_bdev->bd_disk->private_data; | |
226 | dm_put(md); | |
227 | return 0; | |
228 | } | |
229 | ||
230 | static inline struct dm_io *alloc_io(struct mapped_device *md) | |
231 | { | |
232 | return mempool_alloc(md->io_pool, GFP_NOIO); | |
233 | } | |
234 | ||
235 | static inline void free_io(struct mapped_device *md, struct dm_io *io) | |
236 | { | |
237 | mempool_free(io, md->io_pool); | |
238 | } | |
239 | ||
240 | static inline struct target_io *alloc_tio(struct mapped_device *md) | |
241 | { | |
242 | return mempool_alloc(md->tio_pool, GFP_NOIO); | |
243 | } | |
244 | ||
245 | static inline void free_tio(struct mapped_device *md, struct target_io *tio) | |
246 | { | |
247 | mempool_free(tio, md->tio_pool); | |
248 | } | |
249 | ||
3eaf840e JNN |
250 | static void start_io_acct(struct dm_io *io) |
251 | { | |
252 | struct mapped_device *md = io->md; | |
253 | ||
254 | io->start_time = jiffies; | |
255 | ||
256 | preempt_disable(); | |
257 | disk_round_stats(dm_disk(md)); | |
258 | preempt_enable(); | |
259 | dm_disk(md)->in_flight = atomic_inc_return(&md->pending); | |
260 | } | |
261 | ||
262 | static int end_io_acct(struct dm_io *io) | |
263 | { | |
264 | struct mapped_device *md = io->md; | |
265 | struct bio *bio = io->bio; | |
266 | unsigned long duration = jiffies - io->start_time; | |
267 | int pending; | |
268 | int rw = bio_data_dir(bio); | |
269 | ||
270 | preempt_disable(); | |
271 | disk_round_stats(dm_disk(md)); | |
272 | preempt_enable(); | |
273 | dm_disk(md)->in_flight = pending = atomic_dec_return(&md->pending); | |
274 | ||
275 | disk_stat_add(dm_disk(md), ticks[rw], duration); | |
276 | ||
277 | return !pending; | |
278 | } | |
279 | ||
1da177e4 LT |
280 | /* |
281 | * Add the bio to the list of deferred io. | |
282 | */ | |
283 | static int queue_io(struct mapped_device *md, struct bio *bio) | |
284 | { | |
2ca3310e | 285 | down_write(&md->io_lock); |
1da177e4 LT |
286 | |
287 | if (!test_bit(DMF_BLOCK_IO, &md->flags)) { | |
2ca3310e | 288 | up_write(&md->io_lock); |
1da177e4 LT |
289 | return 1; |
290 | } | |
291 | ||
292 | bio_list_add(&md->deferred, bio); | |
293 | ||
2ca3310e | 294 | up_write(&md->io_lock); |
1da177e4 LT |
295 | return 0; /* deferred successfully */ |
296 | } | |
297 | ||
298 | /* | |
299 | * Everyone (including functions in this file), should use this | |
300 | * function to access the md->map field, and make sure they call | |
301 | * dm_table_put() when finished. | |
302 | */ | |
303 | struct dm_table *dm_get_table(struct mapped_device *md) | |
304 | { | |
305 | struct dm_table *t; | |
306 | ||
307 | read_lock(&md->map_lock); | |
308 | t = md->map; | |
309 | if (t) | |
310 | dm_table_get(t); | |
311 | read_unlock(&md->map_lock); | |
312 | ||
313 | return t; | |
314 | } | |
315 | ||
316 | /*----------------------------------------------------------------- | |
317 | * CRUD START: | |
318 | * A more elegant soln is in the works that uses the queue | |
319 | * merge fn, unfortunately there are a couple of changes to | |
320 | * the block layer that I want to make for this. So in the | |
321 | * interests of getting something for people to use I give | |
322 | * you this clearly demarcated crap. | |
323 | *---------------------------------------------------------------*/ | |
324 | ||
325 | /* | |
326 | * Decrements the number of outstanding ios that a bio has been | |
327 | * cloned into, completing the original io if necc. | |
328 | */ | |
858119e1 | 329 | static void dec_pending(struct dm_io *io, int error) |
1da177e4 LT |
330 | { |
331 | if (error) | |
332 | io->error = error; | |
333 | ||
334 | if (atomic_dec_and_test(&io->io_count)) { | |
3eaf840e | 335 | if (end_io_acct(io)) |
1da177e4 LT |
336 | /* nudge anyone waiting on suspend queue */ |
337 | wake_up(&io->md->wait); | |
338 | ||
2056a782 JA |
339 | blk_add_trace_bio(io->md->queue, io->bio, BLK_TA_COMPLETE); |
340 | ||
1da177e4 LT |
341 | bio_endio(io->bio, io->bio->bi_size, io->error); |
342 | free_io(io->md, io); | |
343 | } | |
344 | } | |
345 | ||
346 | static int clone_endio(struct bio *bio, unsigned int done, int error) | |
347 | { | |
348 | int r = 0; | |
349 | struct target_io *tio = bio->bi_private; | |
350 | struct dm_io *io = tio->io; | |
351 | dm_endio_fn endio = tio->ti->type->end_io; | |
352 | ||
353 | if (bio->bi_size) | |
354 | return 1; | |
355 | ||
356 | if (!bio_flagged(bio, BIO_UPTODATE) && !error) | |
357 | error = -EIO; | |
358 | ||
359 | if (endio) { | |
360 | r = endio(tio->ti, bio, error, &tio->info); | |
361 | if (r < 0) | |
362 | error = r; | |
363 | ||
364 | else if (r > 0) | |
365 | /* the target wants another shot at the io */ | |
366 | return 1; | |
367 | } | |
368 | ||
369 | free_tio(io->md, tio); | |
370 | dec_pending(io, error); | |
371 | bio_put(bio); | |
372 | return r; | |
373 | } | |
374 | ||
375 | static sector_t max_io_len(struct mapped_device *md, | |
376 | sector_t sector, struct dm_target *ti) | |
377 | { | |
378 | sector_t offset = sector - ti->begin; | |
379 | sector_t len = ti->len - offset; | |
380 | ||
381 | /* | |
382 | * Does the target need to split even further ? | |
383 | */ | |
384 | if (ti->split_io) { | |
385 | sector_t boundary; | |
386 | boundary = ((offset + ti->split_io) & ~(ti->split_io - 1)) | |
387 | - offset; | |
388 | if (len > boundary) | |
389 | len = boundary; | |
390 | } | |
391 | ||
392 | return len; | |
393 | } | |
394 | ||
395 | static void __map_bio(struct dm_target *ti, struct bio *clone, | |
396 | struct target_io *tio) | |
397 | { | |
398 | int r; | |
2056a782 | 399 | sector_t sector; |
1da177e4 LT |
400 | |
401 | /* | |
402 | * Sanity checks. | |
403 | */ | |
404 | BUG_ON(!clone->bi_size); | |
405 | ||
406 | clone->bi_end_io = clone_endio; | |
407 | clone->bi_private = tio; | |
408 | ||
409 | /* | |
410 | * Map the clone. If r == 0 we don't need to do | |
411 | * anything, the target has assumed ownership of | |
412 | * this io. | |
413 | */ | |
414 | atomic_inc(&tio->io->io_count); | |
2056a782 | 415 | sector = clone->bi_sector; |
1da177e4 | 416 | r = ti->type->map(ti, clone, &tio->info); |
2056a782 | 417 | if (r > 0) { |
1da177e4 | 418 | /* the bio has been remapped so dispatch it */ |
2056a782 JA |
419 | |
420 | blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone, | |
421 | tio->io->bio->bi_bdev->bd_dev, sector, | |
422 | clone->bi_sector); | |
423 | ||
1da177e4 | 424 | generic_make_request(clone); |
2056a782 | 425 | } |
1da177e4 LT |
426 | |
427 | else if (r < 0) { | |
428 | /* error the io and bail out */ | |
429 | struct dm_io *io = tio->io; | |
430 | free_tio(tio->io->md, tio); | |
f6a80ea8 | 431 | dec_pending(io, r); |
1da177e4 LT |
432 | bio_put(clone); |
433 | } | |
434 | } | |
435 | ||
436 | struct clone_info { | |
437 | struct mapped_device *md; | |
438 | struct dm_table *map; | |
439 | struct bio *bio; | |
440 | struct dm_io *io; | |
441 | sector_t sector; | |
442 | sector_t sector_count; | |
443 | unsigned short idx; | |
444 | }; | |
445 | ||
3676347a PO |
446 | static void dm_bio_destructor(struct bio *bio) |
447 | { | |
448 | bio_free(bio, dm_set); | |
449 | } | |
450 | ||
1da177e4 LT |
451 | /* |
452 | * Creates a little bio that is just does part of a bvec. | |
453 | */ | |
454 | static struct bio *split_bvec(struct bio *bio, sector_t sector, | |
455 | unsigned short idx, unsigned int offset, | |
456 | unsigned int len) | |
457 | { | |
458 | struct bio *clone; | |
459 | struct bio_vec *bv = bio->bi_io_vec + idx; | |
460 | ||
461 | clone = bio_alloc_bioset(GFP_NOIO, 1, dm_set); | |
3676347a | 462 | clone->bi_destructor = dm_bio_destructor; |
1da177e4 LT |
463 | *clone->bi_io_vec = *bv; |
464 | ||
465 | clone->bi_sector = sector; | |
466 | clone->bi_bdev = bio->bi_bdev; | |
467 | clone->bi_rw = bio->bi_rw; | |
468 | clone->bi_vcnt = 1; | |
469 | clone->bi_size = to_bytes(len); | |
470 | clone->bi_io_vec->bv_offset = offset; | |
471 | clone->bi_io_vec->bv_len = clone->bi_size; | |
472 | ||
473 | return clone; | |
474 | } | |
475 | ||
476 | /* | |
477 | * Creates a bio that consists of range of complete bvecs. | |
478 | */ | |
479 | static struct bio *clone_bio(struct bio *bio, sector_t sector, | |
480 | unsigned short idx, unsigned short bv_count, | |
481 | unsigned int len) | |
482 | { | |
483 | struct bio *clone; | |
484 | ||
485 | clone = bio_clone(bio, GFP_NOIO); | |
486 | clone->bi_sector = sector; | |
487 | clone->bi_idx = idx; | |
488 | clone->bi_vcnt = idx + bv_count; | |
489 | clone->bi_size = to_bytes(len); | |
490 | clone->bi_flags &= ~(1 << BIO_SEG_VALID); | |
491 | ||
492 | return clone; | |
493 | } | |
494 | ||
495 | static void __clone_and_map(struct clone_info *ci) | |
496 | { | |
497 | struct bio *clone, *bio = ci->bio; | |
498 | struct dm_target *ti = dm_table_find_target(ci->map, ci->sector); | |
499 | sector_t len = 0, max = max_io_len(ci->md, ci->sector, ti); | |
500 | struct target_io *tio; | |
501 | ||
502 | /* | |
503 | * Allocate a target io object. | |
504 | */ | |
505 | tio = alloc_tio(ci->md); | |
506 | tio->io = ci->io; | |
507 | tio->ti = ti; | |
508 | memset(&tio->info, 0, sizeof(tio->info)); | |
509 | ||
510 | if (ci->sector_count <= max) { | |
511 | /* | |
512 | * Optimise for the simple case where we can do all of | |
513 | * the remaining io with a single clone. | |
514 | */ | |
515 | clone = clone_bio(bio, ci->sector, ci->idx, | |
516 | bio->bi_vcnt - ci->idx, ci->sector_count); | |
517 | __map_bio(ti, clone, tio); | |
518 | ci->sector_count = 0; | |
519 | ||
520 | } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { | |
521 | /* | |
522 | * There are some bvecs that don't span targets. | |
523 | * Do as many of these as possible. | |
524 | */ | |
525 | int i; | |
526 | sector_t remaining = max; | |
527 | sector_t bv_len; | |
528 | ||
529 | for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) { | |
530 | bv_len = to_sector(bio->bi_io_vec[i].bv_len); | |
531 | ||
532 | if (bv_len > remaining) | |
533 | break; | |
534 | ||
535 | remaining -= bv_len; | |
536 | len += bv_len; | |
537 | } | |
538 | ||
539 | clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len); | |
540 | __map_bio(ti, clone, tio); | |
541 | ||
542 | ci->sector += len; | |
543 | ci->sector_count -= len; | |
544 | ci->idx = i; | |
545 | ||
546 | } else { | |
547 | /* | |
d2044a94 | 548 | * Handle a bvec that must be split between two or more targets. |
1da177e4 LT |
549 | */ |
550 | struct bio_vec *bv = bio->bi_io_vec + ci->idx; | |
d2044a94 AK |
551 | sector_t remaining = to_sector(bv->bv_len); |
552 | unsigned int offset = 0; | |
1da177e4 | 553 | |
d2044a94 AK |
554 | do { |
555 | if (offset) { | |
556 | ti = dm_table_find_target(ci->map, ci->sector); | |
557 | max = max_io_len(ci->md, ci->sector, ti); | |
1da177e4 | 558 | |
d2044a94 AK |
559 | tio = alloc_tio(ci->md); |
560 | tio->io = ci->io; | |
561 | tio->ti = ti; | |
562 | memset(&tio->info, 0, sizeof(tio->info)); | |
563 | } | |
564 | ||
565 | len = min(remaining, max); | |
566 | ||
567 | clone = split_bvec(bio, ci->sector, ci->idx, | |
568 | bv->bv_offset + offset, len); | |
569 | ||
570 | __map_bio(ti, clone, tio); | |
571 | ||
572 | ci->sector += len; | |
573 | ci->sector_count -= len; | |
574 | offset += to_bytes(len); | |
575 | } while (remaining -= len); | |
1da177e4 | 576 | |
1da177e4 LT |
577 | ci->idx++; |
578 | } | |
579 | } | |
580 | ||
581 | /* | |
582 | * Split the bio into several clones. | |
583 | */ | |
584 | static void __split_bio(struct mapped_device *md, struct bio *bio) | |
585 | { | |
586 | struct clone_info ci; | |
587 | ||
588 | ci.map = dm_get_table(md); | |
589 | if (!ci.map) { | |
590 | bio_io_error(bio, bio->bi_size); | |
591 | return; | |
592 | } | |
593 | ||
594 | ci.md = md; | |
595 | ci.bio = bio; | |
596 | ci.io = alloc_io(md); | |
597 | ci.io->error = 0; | |
598 | atomic_set(&ci.io->io_count, 1); | |
599 | ci.io->bio = bio; | |
600 | ci.io->md = md; | |
601 | ci.sector = bio->bi_sector; | |
602 | ci.sector_count = bio_sectors(bio); | |
603 | ci.idx = bio->bi_idx; | |
604 | ||
3eaf840e | 605 | start_io_acct(ci.io); |
1da177e4 LT |
606 | while (ci.sector_count) |
607 | __clone_and_map(&ci); | |
608 | ||
609 | /* drop the extra reference count */ | |
610 | dec_pending(ci.io, 0); | |
611 | dm_table_put(ci.map); | |
612 | } | |
613 | /*----------------------------------------------------------------- | |
614 | * CRUD END | |
615 | *---------------------------------------------------------------*/ | |
616 | ||
617 | /* | |
618 | * The request function that just remaps the bio built up by | |
619 | * dm_merge_bvec. | |
620 | */ | |
621 | static int dm_request(request_queue_t *q, struct bio *bio) | |
622 | { | |
623 | int r; | |
12f03a49 | 624 | int rw = bio_data_dir(bio); |
1da177e4 LT |
625 | struct mapped_device *md = q->queuedata; |
626 | ||
2ca3310e | 627 | down_read(&md->io_lock); |
1da177e4 | 628 | |
12f03a49 KC |
629 | disk_stat_inc(dm_disk(md), ios[rw]); |
630 | disk_stat_add(dm_disk(md), sectors[rw], bio_sectors(bio)); | |
631 | ||
1da177e4 LT |
632 | /* |
633 | * If we're suspended we have to queue | |
634 | * this io for later. | |
635 | */ | |
636 | while (test_bit(DMF_BLOCK_IO, &md->flags)) { | |
2ca3310e | 637 | up_read(&md->io_lock); |
1da177e4 LT |
638 | |
639 | if (bio_rw(bio) == READA) { | |
640 | bio_io_error(bio, bio->bi_size); | |
641 | return 0; | |
642 | } | |
643 | ||
644 | r = queue_io(md, bio); | |
645 | if (r < 0) { | |
646 | bio_io_error(bio, bio->bi_size); | |
647 | return 0; | |
648 | ||
649 | } else if (r == 0) | |
650 | return 0; /* deferred successfully */ | |
651 | ||
652 | /* | |
653 | * We're in a while loop, because someone could suspend | |
654 | * before we get to the following read lock. | |
655 | */ | |
2ca3310e | 656 | down_read(&md->io_lock); |
1da177e4 LT |
657 | } |
658 | ||
659 | __split_bio(md, bio); | |
2ca3310e | 660 | up_read(&md->io_lock); |
1da177e4 LT |
661 | return 0; |
662 | } | |
663 | ||
664 | static int dm_flush_all(request_queue_t *q, struct gendisk *disk, | |
665 | sector_t *error_sector) | |
666 | { | |
667 | struct mapped_device *md = q->queuedata; | |
668 | struct dm_table *map = dm_get_table(md); | |
669 | int ret = -ENXIO; | |
670 | ||
671 | if (map) { | |
cf222b37 | 672 | ret = dm_table_flush_all(map); |
1da177e4 LT |
673 | dm_table_put(map); |
674 | } | |
675 | ||
676 | return ret; | |
677 | } | |
678 | ||
679 | static void dm_unplug_all(request_queue_t *q) | |
680 | { | |
681 | struct mapped_device *md = q->queuedata; | |
682 | struct dm_table *map = dm_get_table(md); | |
683 | ||
684 | if (map) { | |
685 | dm_table_unplug_all(map); | |
686 | dm_table_put(map); | |
687 | } | |
688 | } | |
689 | ||
690 | static int dm_any_congested(void *congested_data, int bdi_bits) | |
691 | { | |
692 | int r; | |
693 | struct mapped_device *md = (struct mapped_device *) congested_data; | |
694 | struct dm_table *map = dm_get_table(md); | |
695 | ||
696 | if (!map || test_bit(DMF_BLOCK_IO, &md->flags)) | |
697 | r = bdi_bits; | |
698 | else | |
699 | r = dm_table_any_congested(map, bdi_bits); | |
700 | ||
701 | dm_table_put(map); | |
702 | return r; | |
703 | } | |
704 | ||
705 | /*----------------------------------------------------------------- | |
706 | * An IDR is used to keep track of allocated minor numbers. | |
707 | *---------------------------------------------------------------*/ | |
708 | static DECLARE_MUTEX(_minor_lock); | |
709 | static DEFINE_IDR(_minor_idr); | |
710 | ||
711 | static void free_minor(unsigned int minor) | |
712 | { | |
713 | down(&_minor_lock); | |
714 | idr_remove(&_minor_idr, minor); | |
715 | up(&_minor_lock); | |
716 | } | |
717 | ||
718 | /* | |
719 | * See if the device with a specific minor # is free. | |
720 | */ | |
721 | static int specific_minor(struct mapped_device *md, unsigned int minor) | |
722 | { | |
723 | int r, m; | |
724 | ||
725 | if (minor >= (1 << MINORBITS)) | |
726 | return -EINVAL; | |
727 | ||
728 | down(&_minor_lock); | |
729 | ||
730 | if (idr_find(&_minor_idr, minor)) { | |
731 | r = -EBUSY; | |
732 | goto out; | |
733 | } | |
734 | ||
735 | r = idr_pre_get(&_minor_idr, GFP_KERNEL); | |
736 | if (!r) { | |
737 | r = -ENOMEM; | |
738 | goto out; | |
739 | } | |
740 | ||
741 | r = idr_get_new_above(&_minor_idr, md, minor, &m); | |
742 | if (r) { | |
743 | goto out; | |
744 | } | |
745 | ||
746 | if (m != minor) { | |
747 | idr_remove(&_minor_idr, m); | |
748 | r = -EBUSY; | |
749 | goto out; | |
750 | } | |
751 | ||
752 | out: | |
753 | up(&_minor_lock); | |
754 | return r; | |
755 | } | |
756 | ||
757 | static int next_free_minor(struct mapped_device *md, unsigned int *minor) | |
758 | { | |
759 | int r; | |
760 | unsigned int m; | |
761 | ||
762 | down(&_minor_lock); | |
763 | ||
764 | r = idr_pre_get(&_minor_idr, GFP_KERNEL); | |
765 | if (!r) { | |
766 | r = -ENOMEM; | |
767 | goto out; | |
768 | } | |
769 | ||
770 | r = idr_get_new(&_minor_idr, md, &m); | |
771 | if (r) { | |
772 | goto out; | |
773 | } | |
774 | ||
775 | if (m >= (1 << MINORBITS)) { | |
776 | idr_remove(&_minor_idr, m); | |
777 | r = -ENOSPC; | |
778 | goto out; | |
779 | } | |
780 | ||
781 | *minor = m; | |
782 | ||
783 | out: | |
784 | up(&_minor_lock); | |
785 | return r; | |
786 | } | |
787 | ||
788 | static struct block_device_operations dm_blk_dops; | |
789 | ||
790 | /* | |
791 | * Allocate and initialise a blank device with a given minor. | |
792 | */ | |
793 | static struct mapped_device *alloc_dev(unsigned int minor, int persistent) | |
794 | { | |
795 | int r; | |
796 | struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL); | |
797 | ||
798 | if (!md) { | |
799 | DMWARN("unable to allocate device, out of memory."); | |
800 | return NULL; | |
801 | } | |
802 | ||
803 | /* get a minor number for the dev */ | |
804 | r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor); | |
805 | if (r < 0) | |
806 | goto bad1; | |
807 | ||
808 | memset(md, 0, sizeof(*md)); | |
2ca3310e AK |
809 | init_rwsem(&md->io_lock); |
810 | init_MUTEX(&md->suspend_lock); | |
1da177e4 LT |
811 | rwlock_init(&md->map_lock); |
812 | atomic_set(&md->holders, 1); | |
813 | atomic_set(&md->event_nr, 0); | |
814 | ||
815 | md->queue = blk_alloc_queue(GFP_KERNEL); | |
816 | if (!md->queue) | |
817 | goto bad1; | |
818 | ||
819 | md->queue->queuedata = md; | |
820 | md->queue->backing_dev_info.congested_fn = dm_any_congested; | |
821 | md->queue->backing_dev_info.congested_data = md; | |
822 | blk_queue_make_request(md->queue, dm_request); | |
daef265f | 823 | blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); |
1da177e4 LT |
824 | md->queue->unplug_fn = dm_unplug_all; |
825 | md->queue->issue_flush_fn = dm_flush_all; | |
826 | ||
93d2341c | 827 | md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache); |
1da177e4 LT |
828 | if (!md->io_pool) |
829 | goto bad2; | |
830 | ||
93d2341c | 831 | md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache); |
1da177e4 LT |
832 | if (!md->tio_pool) |
833 | goto bad3; | |
834 | ||
835 | md->disk = alloc_disk(1); | |
836 | if (!md->disk) | |
837 | goto bad4; | |
838 | ||
839 | md->disk->major = _major; | |
840 | md->disk->first_minor = minor; | |
841 | md->disk->fops = &dm_blk_dops; | |
842 | md->disk->queue = md->queue; | |
843 | md->disk->private_data = md; | |
844 | sprintf(md->disk->disk_name, "dm-%d", minor); | |
845 | add_disk(md->disk); | |
7e51f257 | 846 | format_dev_t(md->name, MKDEV(_major, minor)); |
1da177e4 LT |
847 | |
848 | atomic_set(&md->pending, 0); | |
849 | init_waitqueue_head(&md->wait); | |
850 | init_waitqueue_head(&md->eventq); | |
851 | ||
852 | return md; | |
853 | ||
854 | bad4: | |
855 | mempool_destroy(md->tio_pool); | |
856 | bad3: | |
857 | mempool_destroy(md->io_pool); | |
858 | bad2: | |
1312f40e | 859 | blk_cleanup_queue(md->queue); |
1da177e4 LT |
860 | free_minor(minor); |
861 | bad1: | |
862 | kfree(md); | |
863 | return NULL; | |
864 | } | |
865 | ||
866 | static void free_dev(struct mapped_device *md) | |
867 | { | |
63d94e48 JN |
868 | unsigned int minor = md->disk->first_minor; |
869 | ||
d9dde59b JN |
870 | if (md->suspended_bdev) { |
871 | thaw_bdev(md->suspended_bdev, NULL); | |
872 | bdput(md->suspended_bdev); | |
873 | } | |
1da177e4 LT |
874 | mempool_destroy(md->tio_pool); |
875 | mempool_destroy(md->io_pool); | |
876 | del_gendisk(md->disk); | |
63d94e48 | 877 | free_minor(minor); |
1da177e4 | 878 | put_disk(md->disk); |
1312f40e | 879 | blk_cleanup_queue(md->queue); |
1da177e4 LT |
880 | kfree(md); |
881 | } | |
882 | ||
883 | /* | |
884 | * Bind a table to the device. | |
885 | */ | |
886 | static void event_callback(void *context) | |
887 | { | |
888 | struct mapped_device *md = (struct mapped_device *) context; | |
889 | ||
890 | atomic_inc(&md->event_nr); | |
891 | wake_up(&md->eventq); | |
892 | } | |
893 | ||
4e90188b | 894 | static void __set_size(struct mapped_device *md, sector_t size) |
1da177e4 | 895 | { |
4e90188b | 896 | set_capacity(md->disk, size); |
1da177e4 | 897 | |
1b1dcc1b | 898 | mutex_lock(&md->suspended_bdev->bd_inode->i_mutex); |
e39e2e95 | 899 | i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); |
1b1dcc1b | 900 | mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex); |
1da177e4 LT |
901 | } |
902 | ||
903 | static int __bind(struct mapped_device *md, struct dm_table *t) | |
904 | { | |
905 | request_queue_t *q = md->queue; | |
906 | sector_t size; | |
907 | ||
908 | size = dm_table_get_size(t); | |
4e90188b | 909 | __set_size(md, size); |
1da177e4 LT |
910 | if (size == 0) |
911 | return 0; | |
912 | ||
2ca3310e AK |
913 | dm_table_get(t); |
914 | dm_table_event_callback(t, event_callback, md); | |
915 | ||
1da177e4 LT |
916 | write_lock(&md->map_lock); |
917 | md->map = t; | |
2ca3310e | 918 | dm_table_set_restrictions(t, q); |
1da177e4 LT |
919 | write_unlock(&md->map_lock); |
920 | ||
1da177e4 LT |
921 | return 0; |
922 | } | |
923 | ||
924 | static void __unbind(struct mapped_device *md) | |
925 | { | |
926 | struct dm_table *map = md->map; | |
927 | ||
928 | if (!map) | |
929 | return; | |
930 | ||
931 | dm_table_event_callback(map, NULL, NULL); | |
932 | write_lock(&md->map_lock); | |
933 | md->map = NULL; | |
934 | write_unlock(&md->map_lock); | |
935 | dm_table_put(map); | |
936 | } | |
937 | ||
938 | /* | |
939 | * Constructor for a new device. | |
940 | */ | |
941 | static int create_aux(unsigned int minor, int persistent, | |
942 | struct mapped_device **result) | |
943 | { | |
944 | struct mapped_device *md; | |
945 | ||
946 | md = alloc_dev(minor, persistent); | |
947 | if (!md) | |
948 | return -ENXIO; | |
949 | ||
950 | *result = md; | |
951 | return 0; | |
952 | } | |
953 | ||
954 | int dm_create(struct mapped_device **result) | |
955 | { | |
956 | return create_aux(0, 0, result); | |
957 | } | |
958 | ||
959 | int dm_create_with_minor(unsigned int minor, struct mapped_device **result) | |
960 | { | |
961 | return create_aux(minor, 1, result); | |
962 | } | |
963 | ||
637842cf | 964 | static struct mapped_device *dm_find_md(dev_t dev) |
1da177e4 LT |
965 | { |
966 | struct mapped_device *md; | |
1da177e4 LT |
967 | unsigned minor = MINOR(dev); |
968 | ||
969 | if (MAJOR(dev) != _major || minor >= (1 << MINORBITS)) | |
970 | return NULL; | |
971 | ||
972 | down(&_minor_lock); | |
973 | ||
974 | md = idr_find(&_minor_idr, minor); | |
637842cf DT |
975 | if (!md || (dm_disk(md)->first_minor != minor)) |
976 | md = NULL; | |
1da177e4 LT |
977 | |
978 | up(&_minor_lock); | |
979 | ||
637842cf DT |
980 | return md; |
981 | } | |
982 | ||
d229a958 DT |
983 | struct mapped_device *dm_get_md(dev_t dev) |
984 | { | |
985 | struct mapped_device *md = dm_find_md(dev); | |
986 | ||
987 | if (md) | |
988 | dm_get(md); | |
989 | ||
990 | return md; | |
991 | } | |
992 | ||
637842cf DT |
993 | void *dm_get_mdptr(dev_t dev) |
994 | { | |
995 | struct mapped_device *md; | |
996 | void *mdptr = NULL; | |
997 | ||
998 | md = dm_find_md(dev); | |
999 | if (md) | |
1000 | mdptr = md->interface_ptr; | |
1da177e4 LT |
1001 | return mdptr; |
1002 | } | |
1003 | ||
1004 | void dm_set_mdptr(struct mapped_device *md, void *ptr) | |
1005 | { | |
1006 | md->interface_ptr = ptr; | |
1007 | } | |
1008 | ||
1009 | void dm_get(struct mapped_device *md) | |
1010 | { | |
1011 | atomic_inc(&md->holders); | |
1012 | } | |
1013 | ||
1014 | void dm_put(struct mapped_device *md) | |
1015 | { | |
1016 | struct dm_table *map = dm_get_table(md); | |
1017 | ||
1018 | if (atomic_dec_and_test(&md->holders)) { | |
cf222b37 | 1019 | if (!dm_suspended(md)) { |
1da177e4 LT |
1020 | dm_table_presuspend_targets(map); |
1021 | dm_table_postsuspend_targets(map); | |
1022 | } | |
1023 | __unbind(md); | |
1024 | free_dev(md); | |
1025 | } | |
1026 | ||
1027 | dm_table_put(map); | |
1028 | } | |
1029 | ||
1030 | /* | |
1031 | * Process the deferred bios | |
1032 | */ | |
1033 | static void __flush_deferred_io(struct mapped_device *md, struct bio *c) | |
1034 | { | |
1035 | struct bio *n; | |
1036 | ||
1037 | while (c) { | |
1038 | n = c->bi_next; | |
1039 | c->bi_next = NULL; | |
1040 | __split_bio(md, c); | |
1041 | c = n; | |
1042 | } | |
1043 | } | |
1044 | ||
1045 | /* | |
1046 | * Swap in a new table (destroying old one). | |
1047 | */ | |
1048 | int dm_swap_table(struct mapped_device *md, struct dm_table *table) | |
1049 | { | |
93c534ae | 1050 | int r = -EINVAL; |
1da177e4 | 1051 | |
2ca3310e | 1052 | down(&md->suspend_lock); |
1da177e4 LT |
1053 | |
1054 | /* device must be suspended */ | |
cf222b37 | 1055 | if (!dm_suspended(md)) |
93c534ae | 1056 | goto out; |
1da177e4 LT |
1057 | |
1058 | __unbind(md); | |
1059 | r = __bind(md, table); | |
1da177e4 | 1060 | |
93c534ae | 1061 | out: |
2ca3310e | 1062 | up(&md->suspend_lock); |
93c534ae | 1063 | return r; |
1da177e4 LT |
1064 | } |
1065 | ||
1066 | /* | |
1067 | * Functions to lock and unlock any filesystem running on the | |
1068 | * device. | |
1069 | */ | |
2ca3310e | 1070 | static int lock_fs(struct mapped_device *md) |
1da177e4 | 1071 | { |
e39e2e95 | 1072 | int r; |
1da177e4 LT |
1073 | |
1074 | WARN_ON(md->frozen_sb); | |
dfbe03f6 | 1075 | |
e39e2e95 | 1076 | md->frozen_sb = freeze_bdev(md->suspended_bdev); |
dfbe03f6 | 1077 | if (IS_ERR(md->frozen_sb)) { |
cf222b37 | 1078 | r = PTR_ERR(md->frozen_sb); |
e39e2e95 AK |
1079 | md->frozen_sb = NULL; |
1080 | return r; | |
dfbe03f6 AK |
1081 | } |
1082 | ||
aa8d7c2f AK |
1083 | set_bit(DMF_FROZEN, &md->flags); |
1084 | ||
1da177e4 | 1085 | /* don't bdput right now, we don't want the bdev |
e39e2e95 | 1086 | * to go away while it is locked. |
1da177e4 LT |
1087 | */ |
1088 | return 0; | |
1089 | } | |
1090 | ||
2ca3310e | 1091 | static void unlock_fs(struct mapped_device *md) |
1da177e4 | 1092 | { |
aa8d7c2f AK |
1093 | if (!test_bit(DMF_FROZEN, &md->flags)) |
1094 | return; | |
1095 | ||
e39e2e95 | 1096 | thaw_bdev(md->suspended_bdev, md->frozen_sb); |
1da177e4 | 1097 | md->frozen_sb = NULL; |
aa8d7c2f | 1098 | clear_bit(DMF_FROZEN, &md->flags); |
1da177e4 LT |
1099 | } |
1100 | ||
1101 | /* | |
1102 | * We need to be able to change a mapping table under a mounted | |
1103 | * filesystem. For example we might want to move some data in | |
1104 | * the background. Before the table can be swapped with | |
1105 | * dm_bind_table, dm_suspend must be called to flush any in | |
1106 | * flight bios and ensure that any further io gets deferred. | |
1107 | */ | |
aa8d7c2f | 1108 | int dm_suspend(struct mapped_device *md, int do_lockfs) |
1da177e4 | 1109 | { |
2ca3310e | 1110 | struct dm_table *map = NULL; |
1da177e4 | 1111 | DECLARE_WAITQUEUE(wait, current); |
1ecac7fd | 1112 | struct bio *def; |
cf222b37 | 1113 | int r = -EINVAL; |
1da177e4 | 1114 | |
2ca3310e AK |
1115 | down(&md->suspend_lock); |
1116 | ||
1117 | if (dm_suspended(md)) | |
1118 | goto out; | |
1da177e4 LT |
1119 | |
1120 | map = dm_get_table(md); | |
1da177e4 | 1121 | |
cf222b37 AK |
1122 | /* This does not get reverted if there's an error later. */ |
1123 | dm_table_presuspend_targets(map); | |
1124 | ||
e39e2e95 AK |
1125 | md->suspended_bdev = bdget_disk(md->disk, 0); |
1126 | if (!md->suspended_bdev) { | |
1127 | DMWARN("bdget failed in dm_suspend"); | |
1128 | r = -ENOMEM; | |
1129 | goto out; | |
1130 | } | |
1131 | ||
cf222b37 | 1132 | /* Flush I/O to the device. */ |
aa8d7c2f AK |
1133 | if (do_lockfs) { |
1134 | r = lock_fs(md); | |
1135 | if (r) | |
1136 | goto out; | |
1137 | } | |
1da177e4 LT |
1138 | |
1139 | /* | |
354e0071 | 1140 | * First we set the BLOCK_IO flag so no more ios will be mapped. |
1da177e4 | 1141 | */ |
2ca3310e AK |
1142 | down_write(&md->io_lock); |
1143 | set_bit(DMF_BLOCK_IO, &md->flags); | |
1da177e4 | 1144 | |
1da177e4 | 1145 | add_wait_queue(&md->wait, &wait); |
2ca3310e | 1146 | up_write(&md->io_lock); |
1da177e4 LT |
1147 | |
1148 | /* unplug */ | |
2ca3310e | 1149 | if (map) |
1da177e4 | 1150 | dm_table_unplug_all(map); |
1da177e4 LT |
1151 | |
1152 | /* | |
1153 | * Then we wait for the already mapped ios to | |
1154 | * complete. | |
1155 | */ | |
1156 | while (1) { | |
1157 | set_current_state(TASK_INTERRUPTIBLE); | |
1158 | ||
1159 | if (!atomic_read(&md->pending) || signal_pending(current)) | |
1160 | break; | |
1161 | ||
1162 | io_schedule(); | |
1163 | } | |
1164 | set_current_state(TASK_RUNNING); | |
1165 | ||
2ca3310e | 1166 | down_write(&md->io_lock); |
1da177e4 LT |
1167 | remove_wait_queue(&md->wait, &wait); |
1168 | ||
1169 | /* were we interrupted ? */ | |
cf222b37 | 1170 | r = -EINTR; |
2ca3310e | 1171 | if (atomic_read(&md->pending)) { |
1ecac7fd JN |
1172 | clear_bit(DMF_BLOCK_IO, &md->flags); |
1173 | def = bio_list_get(&md->deferred); | |
1174 | __flush_deferred_io(md, def); | |
2ca3310e AK |
1175 | up_write(&md->io_lock); |
1176 | unlock_fs(md); | |
2ca3310e AK |
1177 | goto out; |
1178 | } | |
1179 | up_write(&md->io_lock); | |
1da177e4 | 1180 | |
cf222b37 | 1181 | dm_table_postsuspend_targets(map); |
1da177e4 | 1182 | |
2ca3310e | 1183 | set_bit(DMF_SUSPENDED, &md->flags); |
b84b0287 | 1184 | |
2ca3310e | 1185 | r = 0; |
b84b0287 | 1186 | |
2ca3310e | 1187 | out: |
e39e2e95 AK |
1188 | if (r && md->suspended_bdev) { |
1189 | bdput(md->suspended_bdev); | |
1190 | md->suspended_bdev = NULL; | |
1191 | } | |
1192 | ||
2ca3310e AK |
1193 | dm_table_put(map); |
1194 | up(&md->suspend_lock); | |
cf222b37 | 1195 | return r; |
1da177e4 LT |
1196 | } |
1197 | ||
1198 | int dm_resume(struct mapped_device *md) | |
1199 | { | |
cf222b37 | 1200 | int r = -EINVAL; |
1da177e4 | 1201 | struct bio *def; |
cf222b37 | 1202 | struct dm_table *map = NULL; |
1da177e4 | 1203 | |
2ca3310e AK |
1204 | down(&md->suspend_lock); |
1205 | if (!dm_suspended(md)) | |
cf222b37 | 1206 | goto out; |
cf222b37 AK |
1207 | |
1208 | map = dm_get_table(md); | |
2ca3310e | 1209 | if (!map || !dm_table_get_size(map)) |
cf222b37 | 1210 | goto out; |
1da177e4 LT |
1211 | |
1212 | dm_table_resume_targets(map); | |
2ca3310e AK |
1213 | |
1214 | down_write(&md->io_lock); | |
1da177e4 LT |
1215 | clear_bit(DMF_BLOCK_IO, &md->flags); |
1216 | ||
1217 | def = bio_list_get(&md->deferred); | |
1218 | __flush_deferred_io(md, def); | |
2ca3310e AK |
1219 | up_write(&md->io_lock); |
1220 | ||
1221 | unlock_fs(md); | |
1222 | ||
e39e2e95 AK |
1223 | bdput(md->suspended_bdev); |
1224 | md->suspended_bdev = NULL; | |
1225 | ||
2ca3310e AK |
1226 | clear_bit(DMF_SUSPENDED, &md->flags); |
1227 | ||
1da177e4 | 1228 | dm_table_unplug_all(map); |
1da177e4 | 1229 | |
cf222b37 | 1230 | r = 0; |
2ca3310e | 1231 | |
cf222b37 AK |
1232 | out: |
1233 | dm_table_put(map); | |
2ca3310e AK |
1234 | up(&md->suspend_lock); |
1235 | ||
cf222b37 | 1236 | return r; |
1da177e4 LT |
1237 | } |
1238 | ||
1239 | /*----------------------------------------------------------------- | |
1240 | * Event notification. | |
1241 | *---------------------------------------------------------------*/ | |
1242 | uint32_t dm_get_event_nr(struct mapped_device *md) | |
1243 | { | |
1244 | return atomic_read(&md->event_nr); | |
1245 | } | |
1246 | ||
1247 | int dm_wait_event(struct mapped_device *md, int event_nr) | |
1248 | { | |
1249 | return wait_event_interruptible(md->eventq, | |
1250 | (event_nr != atomic_read(&md->event_nr))); | |
1251 | } | |
1252 | ||
1253 | /* | |
1254 | * The gendisk is only valid as long as you have a reference | |
1255 | * count on 'md'. | |
1256 | */ | |
1257 | struct gendisk *dm_disk(struct mapped_device *md) | |
1258 | { | |
1259 | return md->disk; | |
1260 | } | |
1261 | ||
1262 | int dm_suspended(struct mapped_device *md) | |
1263 | { | |
1264 | return test_bit(DMF_SUSPENDED, &md->flags); | |
1265 | } | |
1266 | ||
1267 | static struct block_device_operations dm_blk_dops = { | |
1268 | .open = dm_blk_open, | |
1269 | .release = dm_blk_close, | |
1270 | .owner = THIS_MODULE | |
1271 | }; | |
1272 | ||
1273 | EXPORT_SYMBOL(dm_get_mapinfo); | |
1274 | ||
1275 | /* | |
1276 | * module hooks | |
1277 | */ | |
1278 | module_init(dm_init); | |
1279 | module_exit(dm_exit); | |
1280 | ||
1281 | module_param(major, uint, 0); | |
1282 | MODULE_PARM_DESC(major, "The major number of the device mapper"); | |
1283 | MODULE_DESCRIPTION(DM_NAME " driver"); | |
1284 | MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); | |
1285 | MODULE_LICENSE("GPL"); |