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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2003 Sistina Software Limited. | |
3 | * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved. | |
4 | * | |
5 | * This file is released under the GPL. | |
6 | */ | |
7 | ||
8 | #include "dm.h" | |
9 | #include "dm-path-selector.h" | |
10 | #include "dm-hw-handler.h" | |
11 | #include "dm-bio-list.h" | |
12 | #include "dm-bio-record.h" | |
13 | ||
14 | #include <linux/ctype.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/mempool.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/pagemap.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/time.h> | |
21 | #include <linux/workqueue.h> | |
22 | #include <asm/atomic.h> | |
23 | ||
24 | #define MESG_STR(x) x, sizeof(x) | |
25 | ||
26 | /* Path properties */ | |
27 | struct pgpath { | |
28 | struct list_head list; | |
29 | ||
30 | struct priority_group *pg; /* Owning PG */ | |
31 | unsigned fail_count; /* Cumulative failure count */ | |
32 | ||
33 | struct path path; | |
34 | }; | |
35 | ||
36 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
37 | ||
38 | /* | |
39 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
40 | * Each has a path selector which controls which path gets used. | |
41 | */ | |
42 | struct priority_group { | |
43 | struct list_head list; | |
44 | ||
45 | struct multipath *m; /* Owning multipath instance */ | |
46 | struct path_selector ps; | |
47 | ||
48 | unsigned pg_num; /* Reference number */ | |
49 | unsigned bypassed; /* Temporarily bypass this PG? */ | |
50 | ||
51 | unsigned nr_pgpaths; /* Number of paths in PG */ | |
52 | struct list_head pgpaths; | |
53 | }; | |
54 | ||
55 | /* Multipath context */ | |
56 | struct multipath { | |
57 | struct list_head list; | |
58 | struct dm_target *ti; | |
59 | ||
60 | spinlock_t lock; | |
61 | ||
62 | struct hw_handler hw_handler; | |
63 | unsigned nr_priority_groups; | |
64 | struct list_head priority_groups; | |
65 | unsigned pg_init_required; /* pg_init needs calling? */ | |
66 | ||
67 | unsigned nr_valid_paths; /* Total number of usable paths */ | |
68 | struct pgpath *current_pgpath; | |
69 | struct priority_group *current_pg; | |
70 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
71 | unsigned repeat_count; /* I/Os left before calling PS again */ | |
72 | ||
73 | unsigned queue_io; /* Must we queue all I/O? */ | |
74 | unsigned queue_if_no_path; /* Queue I/O if last path fails? */ | |
75 | unsigned suspended; /* Has dm core suspended our I/O? */ | |
76 | ||
77 | struct work_struct process_queued_ios; | |
78 | struct bio_list queued_ios; | |
79 | unsigned queue_size; | |
80 | ||
81 | struct work_struct trigger_event; | |
82 | ||
83 | /* | |
84 | * We must use a mempool of mpath_io structs so that we | |
85 | * can resubmit bios on error. | |
86 | */ | |
87 | mempool_t *mpio_pool; | |
88 | }; | |
89 | ||
90 | /* | |
91 | * Context information attached to each bio we process. | |
92 | */ | |
93 | struct mpath_io { | |
94 | struct pgpath *pgpath; | |
95 | struct dm_bio_details details; | |
96 | }; | |
97 | ||
98 | typedef int (*action_fn) (struct pgpath *pgpath); | |
99 | ||
100 | #define MIN_IOS 256 /* Mempool size */ | |
101 | ||
102 | static kmem_cache_t *_mpio_cache; | |
103 | ||
c557308e | 104 | struct workqueue_struct *kmultipathd; |
1da177e4 LT |
105 | static void process_queued_ios(void *data); |
106 | static void trigger_event(void *data); | |
107 | ||
108 | ||
109 | /*----------------------------------------------- | |
110 | * Allocation routines | |
111 | *-----------------------------------------------*/ | |
112 | ||
113 | static struct pgpath *alloc_pgpath(void) | |
114 | { | |
115 | struct pgpath *pgpath = kmalloc(sizeof(*pgpath), GFP_KERNEL); | |
116 | ||
117 | if (pgpath) { | |
118 | memset(pgpath, 0, sizeof(*pgpath)); | |
119 | pgpath->path.is_active = 1; | |
120 | } | |
121 | ||
122 | return pgpath; | |
123 | } | |
124 | ||
125 | static inline void free_pgpath(struct pgpath *pgpath) | |
126 | { | |
127 | kfree(pgpath); | |
128 | } | |
129 | ||
130 | static struct priority_group *alloc_priority_group(void) | |
131 | { | |
132 | struct priority_group *pg; | |
133 | ||
134 | pg = kmalloc(sizeof(*pg), GFP_KERNEL); | |
135 | if (!pg) | |
136 | return NULL; | |
137 | ||
138 | memset(pg, 0, sizeof(*pg)); | |
139 | INIT_LIST_HEAD(&pg->pgpaths); | |
140 | ||
141 | return pg; | |
142 | } | |
143 | ||
144 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
145 | { | |
146 | struct pgpath *pgpath, *tmp; | |
147 | ||
148 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
149 | list_del(&pgpath->list); | |
150 | dm_put_device(ti, pgpath->path.dev); | |
151 | free_pgpath(pgpath); | |
152 | } | |
153 | } | |
154 | ||
155 | static void free_priority_group(struct priority_group *pg, | |
156 | struct dm_target *ti) | |
157 | { | |
158 | struct path_selector *ps = &pg->ps; | |
159 | ||
160 | if (ps->type) { | |
161 | ps->type->destroy(ps); | |
162 | dm_put_path_selector(ps->type); | |
163 | } | |
164 | ||
165 | free_pgpaths(&pg->pgpaths, ti); | |
166 | kfree(pg); | |
167 | } | |
168 | ||
169 | static struct multipath *alloc_multipath(void) | |
170 | { | |
171 | struct multipath *m; | |
172 | ||
173 | m = kmalloc(sizeof(*m), GFP_KERNEL); | |
174 | if (m) { | |
175 | memset(m, 0, sizeof(*m)); | |
176 | INIT_LIST_HEAD(&m->priority_groups); | |
177 | spin_lock_init(&m->lock); | |
178 | m->queue_io = 1; | |
179 | INIT_WORK(&m->process_queued_ios, process_queued_ios, m); | |
180 | INIT_WORK(&m->trigger_event, trigger_event, m); | |
181 | m->mpio_pool = mempool_create(MIN_IOS, mempool_alloc_slab, | |
182 | mempool_free_slab, _mpio_cache); | |
183 | if (!m->mpio_pool) { | |
184 | kfree(m); | |
185 | return NULL; | |
186 | } | |
187 | } | |
188 | ||
189 | return m; | |
190 | } | |
191 | ||
192 | static void free_multipath(struct multipath *m) | |
193 | { | |
194 | struct priority_group *pg, *tmp; | |
195 | struct hw_handler *hwh = &m->hw_handler; | |
196 | ||
197 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
198 | list_del(&pg->list); | |
199 | free_priority_group(pg, m->ti); | |
200 | } | |
201 | ||
202 | if (hwh->type) { | |
203 | hwh->type->destroy(hwh); | |
204 | dm_put_hw_handler(hwh->type); | |
205 | } | |
206 | ||
207 | mempool_destroy(m->mpio_pool); | |
208 | kfree(m); | |
209 | } | |
210 | ||
211 | ||
212 | /*----------------------------------------------- | |
213 | * Path selection | |
214 | *-----------------------------------------------*/ | |
215 | ||
216 | static void __switch_pg(struct multipath *m, struct pgpath *pgpath) | |
217 | { | |
218 | struct hw_handler *hwh = &m->hw_handler; | |
219 | ||
220 | m->current_pg = pgpath->pg; | |
221 | ||
222 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
223 | if (hwh->type && hwh->type->pg_init) { | |
224 | m->pg_init_required = 1; | |
225 | m->queue_io = 1; | |
226 | } else { | |
227 | m->pg_init_required = 0; | |
228 | m->queue_io = 0; | |
229 | } | |
230 | } | |
231 | ||
232 | static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg) | |
233 | { | |
234 | struct path *path; | |
235 | ||
236 | path = pg->ps.type->select_path(&pg->ps, &m->repeat_count); | |
237 | if (!path) | |
238 | return -ENXIO; | |
239 | ||
240 | m->current_pgpath = path_to_pgpath(path); | |
241 | ||
242 | if (m->current_pg != pg) | |
243 | __switch_pg(m, m->current_pgpath); | |
244 | ||
245 | return 0; | |
246 | } | |
247 | ||
248 | static void __choose_pgpath(struct multipath *m) | |
249 | { | |
250 | struct priority_group *pg; | |
251 | unsigned bypassed = 1; | |
252 | ||
253 | if (!m->nr_valid_paths) | |
254 | goto failed; | |
255 | ||
256 | /* Were we instructed to switch PG? */ | |
257 | if (m->next_pg) { | |
258 | pg = m->next_pg; | |
259 | m->next_pg = NULL; | |
260 | if (!__choose_path_in_pg(m, pg)) | |
261 | return; | |
262 | } | |
263 | ||
264 | /* Don't change PG until it has no remaining paths */ | |
265 | if (m->current_pg && !__choose_path_in_pg(m, m->current_pg)) | |
266 | return; | |
267 | ||
268 | /* | |
269 | * Loop through priority groups until we find a valid path. | |
270 | * First time we skip PGs marked 'bypassed'. | |
271 | * Second time we only try the ones we skipped. | |
272 | */ | |
273 | do { | |
274 | list_for_each_entry(pg, &m->priority_groups, list) { | |
275 | if (pg->bypassed == bypassed) | |
276 | continue; | |
277 | if (!__choose_path_in_pg(m, pg)) | |
278 | return; | |
279 | } | |
280 | } while (bypassed--); | |
281 | ||
282 | failed: | |
283 | m->current_pgpath = NULL; | |
284 | m->current_pg = NULL; | |
285 | } | |
286 | ||
287 | static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio, | |
288 | unsigned was_queued) | |
289 | { | |
290 | int r = 1; | |
291 | unsigned long flags; | |
292 | struct pgpath *pgpath; | |
293 | ||
294 | spin_lock_irqsave(&m->lock, flags); | |
295 | ||
296 | /* Do we need to select a new pgpath? */ | |
297 | if (!m->current_pgpath || | |
298 | (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) | |
299 | __choose_pgpath(m); | |
300 | ||
301 | pgpath = m->current_pgpath; | |
302 | ||
303 | if (was_queued) | |
304 | m->queue_size--; | |
305 | ||
306 | if ((pgpath && m->queue_io) || | |
307 | (!pgpath && m->queue_if_no_path && !m->suspended)) { | |
308 | /* Queue for the daemon to resubmit */ | |
309 | bio_list_add(&m->queued_ios, bio); | |
310 | m->queue_size++; | |
311 | if (m->pg_init_required || !m->queue_io) | |
c557308e | 312 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
313 | pgpath = NULL; |
314 | r = 0; | |
315 | } else if (!pgpath) | |
316 | r = -EIO; /* Failed */ | |
317 | else | |
318 | bio->bi_bdev = pgpath->path.dev->bdev; | |
319 | ||
320 | mpio->pgpath = pgpath; | |
321 | ||
322 | spin_unlock_irqrestore(&m->lock, flags); | |
323 | ||
324 | return r; | |
325 | } | |
326 | ||
327 | /* | |
328 | * If we run out of usable paths, should we queue I/O or error it? | |
329 | */ | |
330 | static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path) | |
331 | { | |
332 | unsigned long flags; | |
333 | ||
334 | spin_lock_irqsave(&m->lock, flags); | |
335 | ||
336 | m->queue_if_no_path = queue_if_no_path; | |
337 | if (!m->queue_if_no_path) | |
c557308e | 338 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
339 | |
340 | spin_unlock_irqrestore(&m->lock, flags); | |
341 | ||
342 | return 0; | |
343 | } | |
344 | ||
345 | /*----------------------------------------------------------------- | |
346 | * The multipath daemon is responsible for resubmitting queued ios. | |
347 | *---------------------------------------------------------------*/ | |
348 | ||
349 | static void dispatch_queued_ios(struct multipath *m) | |
350 | { | |
351 | int r; | |
352 | unsigned long flags; | |
353 | struct bio *bio = NULL, *next; | |
354 | struct mpath_io *mpio; | |
355 | union map_info *info; | |
356 | ||
357 | spin_lock_irqsave(&m->lock, flags); | |
358 | bio = bio_list_get(&m->queued_ios); | |
359 | spin_unlock_irqrestore(&m->lock, flags); | |
360 | ||
361 | while (bio) { | |
362 | next = bio->bi_next; | |
363 | bio->bi_next = NULL; | |
364 | ||
365 | info = dm_get_mapinfo(bio); | |
366 | mpio = info->ptr; | |
367 | ||
368 | r = map_io(m, bio, mpio, 1); | |
369 | if (r < 0) | |
370 | bio_endio(bio, bio->bi_size, r); | |
371 | else if (r == 1) | |
372 | generic_make_request(bio); | |
373 | ||
374 | bio = next; | |
375 | } | |
376 | } | |
377 | ||
378 | static void process_queued_ios(void *data) | |
379 | { | |
380 | struct multipath *m = (struct multipath *) data; | |
381 | struct hw_handler *hwh = &m->hw_handler; | |
382 | struct pgpath *pgpath; | |
383 | unsigned init_required, must_queue = 0; | |
384 | unsigned long flags; | |
385 | ||
386 | spin_lock_irqsave(&m->lock, flags); | |
387 | ||
388 | if (!m->current_pgpath) | |
389 | __choose_pgpath(m); | |
390 | ||
391 | pgpath = m->current_pgpath; | |
392 | ||
393 | if ((pgpath && m->queue_io) || | |
394 | (!pgpath && m->queue_if_no_path && !m->suspended)) | |
395 | must_queue = 1; | |
396 | ||
397 | init_required = m->pg_init_required; | |
398 | if (init_required) | |
399 | m->pg_init_required = 0; | |
400 | ||
401 | spin_unlock_irqrestore(&m->lock, flags); | |
402 | ||
403 | if (init_required) | |
404 | hwh->type->pg_init(hwh, pgpath->pg->bypassed, &pgpath->path); | |
405 | ||
406 | if (!must_queue) | |
407 | dispatch_queued_ios(m); | |
408 | } | |
409 | ||
410 | /* | |
411 | * An event is triggered whenever a path is taken out of use. | |
412 | * Includes path failure and PG bypass. | |
413 | */ | |
414 | static void trigger_event(void *data) | |
415 | { | |
416 | struct multipath *m = (struct multipath *) data; | |
417 | ||
418 | dm_table_event(m->ti->table); | |
419 | } | |
420 | ||
421 | /*----------------------------------------------------------------- | |
422 | * Constructor/argument parsing: | |
423 | * <#multipath feature args> [<arg>]* | |
424 | * <#hw_handler args> [hw_handler [<arg>]*] | |
425 | * <#priority groups> | |
426 | * <initial priority group> | |
427 | * [<selector> <#selector args> [<arg>]* | |
428 | * <#paths> <#per-path selector args> | |
429 | * [<path> [<arg>]* ]+ ]+ | |
430 | *---------------------------------------------------------------*/ | |
431 | struct param { | |
432 | unsigned min; | |
433 | unsigned max; | |
434 | char *error; | |
435 | }; | |
436 | ||
437 | #define ESTR(s) ("dm-multipath: " s) | |
438 | ||
439 | static int read_param(struct param *param, char *str, unsigned *v, char **error) | |
440 | { | |
441 | if (!str || | |
442 | (sscanf(str, "%u", v) != 1) || | |
443 | (*v < param->min) || | |
444 | (*v > param->max)) { | |
445 | *error = param->error; | |
446 | return -EINVAL; | |
447 | } | |
448 | ||
449 | return 0; | |
450 | } | |
451 | ||
452 | struct arg_set { | |
453 | unsigned argc; | |
454 | char **argv; | |
455 | }; | |
456 | ||
457 | static char *shift(struct arg_set *as) | |
458 | { | |
459 | char *r; | |
460 | ||
461 | if (as->argc) { | |
462 | as->argc--; | |
463 | r = *as->argv; | |
464 | as->argv++; | |
465 | return r; | |
466 | } | |
467 | ||
468 | return NULL; | |
469 | } | |
470 | ||
471 | static void consume(struct arg_set *as, unsigned n) | |
472 | { | |
473 | BUG_ON (as->argc < n); | |
474 | as->argc -= n; | |
475 | as->argv += n; | |
476 | } | |
477 | ||
478 | static int parse_path_selector(struct arg_set *as, struct priority_group *pg, | |
479 | struct dm_target *ti) | |
480 | { | |
481 | int r; | |
482 | struct path_selector_type *pst; | |
483 | unsigned ps_argc; | |
484 | ||
485 | static struct param _params[] = { | |
486 | {0, 1024, ESTR("invalid number of path selector args")}, | |
487 | }; | |
488 | ||
489 | pst = dm_get_path_selector(shift(as)); | |
490 | if (!pst) { | |
491 | ti->error = ESTR("unknown path selector type"); | |
492 | return -EINVAL; | |
493 | } | |
494 | ||
495 | r = read_param(_params, shift(as), &ps_argc, &ti->error); | |
496 | if (r) | |
497 | return -EINVAL; | |
498 | ||
499 | r = pst->create(&pg->ps, ps_argc, as->argv); | |
500 | if (r) { | |
501 | dm_put_path_selector(pst); | |
502 | ti->error = ESTR("path selector constructor failed"); | |
503 | return r; | |
504 | } | |
505 | ||
506 | pg->ps.type = pst; | |
507 | consume(as, ps_argc); | |
508 | ||
509 | return 0; | |
510 | } | |
511 | ||
512 | static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps, | |
513 | struct dm_target *ti) | |
514 | { | |
515 | int r; | |
516 | struct pgpath *p; | |
517 | ||
518 | /* we need at least a path arg */ | |
519 | if (as->argc < 1) { | |
520 | ti->error = ESTR("no device given"); | |
521 | return NULL; | |
522 | } | |
523 | ||
524 | p = alloc_pgpath(); | |
525 | if (!p) | |
526 | return NULL; | |
527 | ||
528 | r = dm_get_device(ti, shift(as), ti->begin, ti->len, | |
529 | dm_table_get_mode(ti->table), &p->path.dev); | |
530 | if (r) { | |
531 | ti->error = ESTR("error getting device"); | |
532 | goto bad; | |
533 | } | |
534 | ||
535 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); | |
536 | if (r) { | |
537 | dm_put_device(ti, p->path.dev); | |
538 | goto bad; | |
539 | } | |
540 | ||
541 | return p; | |
542 | ||
543 | bad: | |
544 | free_pgpath(p); | |
545 | return NULL; | |
546 | } | |
547 | ||
548 | static struct priority_group *parse_priority_group(struct arg_set *as, | |
549 | struct multipath *m, | |
550 | struct dm_target *ti) | |
551 | { | |
552 | static struct param _params[] = { | |
553 | {1, 1024, ESTR("invalid number of paths")}, | |
554 | {0, 1024, ESTR("invalid number of selector args")} | |
555 | }; | |
556 | ||
557 | int r; | |
558 | unsigned i, nr_selector_args, nr_params; | |
559 | struct priority_group *pg; | |
560 | ||
561 | if (as->argc < 2) { | |
562 | as->argc = 0; | |
563 | ti->error = ESTR("not enough priority group aruments"); | |
564 | return NULL; | |
565 | } | |
566 | ||
567 | pg = alloc_priority_group(); | |
568 | if (!pg) { | |
569 | ti->error = ESTR("couldn't allocate priority group"); | |
570 | return NULL; | |
571 | } | |
572 | pg->m = m; | |
573 | ||
574 | r = parse_path_selector(as, pg, ti); | |
575 | if (r) | |
576 | goto bad; | |
577 | ||
578 | /* | |
579 | * read the paths | |
580 | */ | |
581 | r = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error); | |
582 | if (r) | |
583 | goto bad; | |
584 | ||
585 | r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error); | |
586 | if (r) | |
587 | goto bad; | |
588 | ||
589 | nr_params = 1 + nr_selector_args; | |
590 | for (i = 0; i < pg->nr_pgpaths; i++) { | |
591 | struct pgpath *pgpath; | |
592 | struct arg_set path_args; | |
593 | ||
594 | if (as->argc < nr_params) | |
595 | goto bad; | |
596 | ||
597 | path_args.argc = nr_params; | |
598 | path_args.argv = as->argv; | |
599 | ||
600 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
601 | if (!pgpath) | |
602 | goto bad; | |
603 | ||
604 | pgpath->pg = pg; | |
605 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
606 | consume(as, nr_params); | |
607 | } | |
608 | ||
609 | return pg; | |
610 | ||
611 | bad: | |
612 | free_priority_group(pg, ti); | |
613 | return NULL; | |
614 | } | |
615 | ||
616 | static int parse_hw_handler(struct arg_set *as, struct multipath *m, | |
617 | struct dm_target *ti) | |
618 | { | |
619 | int r; | |
620 | struct hw_handler_type *hwht; | |
621 | unsigned hw_argc; | |
622 | ||
623 | static struct param _params[] = { | |
624 | {0, 1024, ESTR("invalid number of hardware handler args")}, | |
625 | }; | |
626 | ||
627 | r = read_param(_params, shift(as), &hw_argc, &ti->error); | |
628 | if (r) | |
629 | return -EINVAL; | |
630 | ||
631 | if (!hw_argc) | |
632 | return 0; | |
633 | ||
634 | hwht = dm_get_hw_handler(shift(as)); | |
635 | if (!hwht) { | |
636 | ti->error = ESTR("unknown hardware handler type"); | |
637 | return -EINVAL; | |
638 | } | |
639 | ||
640 | r = hwht->create(&m->hw_handler, hw_argc - 1, as->argv); | |
641 | if (r) { | |
642 | dm_put_hw_handler(hwht); | |
643 | ti->error = ESTR("hardware handler constructor failed"); | |
644 | return r; | |
645 | } | |
646 | ||
647 | m->hw_handler.type = hwht; | |
648 | consume(as, hw_argc - 1); | |
649 | ||
650 | return 0; | |
651 | } | |
652 | ||
653 | static int parse_features(struct arg_set *as, struct multipath *m, | |
654 | struct dm_target *ti) | |
655 | { | |
656 | int r; | |
657 | unsigned argc; | |
658 | ||
659 | static struct param _params[] = { | |
660 | {0, 1, ESTR("invalid number of feature args")}, | |
661 | }; | |
662 | ||
663 | r = read_param(_params, shift(as), &argc, &ti->error); | |
664 | if (r) | |
665 | return -EINVAL; | |
666 | ||
667 | if (!argc) | |
668 | return 0; | |
669 | ||
670 | if (!strnicmp(shift(as), MESG_STR("queue_if_no_path"))) | |
671 | return queue_if_no_path(m, 1); | |
672 | else { | |
673 | ti->error = "Unrecognised multipath feature request"; | |
674 | return -EINVAL; | |
675 | } | |
676 | } | |
677 | ||
678 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
679 | char **argv) | |
680 | { | |
681 | /* target parameters */ | |
682 | static struct param _params[] = { | |
683 | {1, 1024, ESTR("invalid number of priority groups")}, | |
684 | {1, 1024, ESTR("invalid initial priority group number")}, | |
685 | }; | |
686 | ||
687 | int r; | |
688 | struct multipath *m; | |
689 | struct arg_set as; | |
690 | unsigned pg_count = 0; | |
691 | unsigned next_pg_num; | |
692 | ||
693 | as.argc = argc; | |
694 | as.argv = argv; | |
695 | ||
696 | m = alloc_multipath(); | |
697 | if (!m) { | |
698 | ti->error = ESTR("can't allocate multipath"); | |
699 | return -EINVAL; | |
700 | } | |
701 | ||
702 | r = parse_features(&as, m, ti); | |
703 | if (r) | |
704 | goto bad; | |
705 | ||
706 | r = parse_hw_handler(&as, m, ti); | |
707 | if (r) | |
708 | goto bad; | |
709 | ||
710 | r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error); | |
711 | if (r) | |
712 | goto bad; | |
713 | ||
714 | r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error); | |
715 | if (r) | |
716 | goto bad; | |
717 | ||
718 | /* parse the priority groups */ | |
719 | while (as.argc) { | |
720 | struct priority_group *pg; | |
721 | ||
722 | pg = parse_priority_group(&as, m, ti); | |
723 | if (!pg) { | |
724 | r = -EINVAL; | |
725 | goto bad; | |
726 | } | |
727 | ||
728 | m->nr_valid_paths += pg->nr_pgpaths; | |
729 | list_add_tail(&pg->list, &m->priority_groups); | |
730 | pg_count++; | |
731 | pg->pg_num = pg_count; | |
732 | if (!--next_pg_num) | |
733 | m->next_pg = pg; | |
734 | } | |
735 | ||
736 | if (pg_count != m->nr_priority_groups) { | |
737 | ti->error = ESTR("priority group count mismatch"); | |
738 | r = -EINVAL; | |
739 | goto bad; | |
740 | } | |
741 | ||
742 | ti->private = m; | |
743 | m->ti = ti; | |
744 | ||
745 | return 0; | |
746 | ||
747 | bad: | |
748 | free_multipath(m); | |
749 | return r; | |
750 | } | |
751 | ||
752 | static void multipath_dtr(struct dm_target *ti) | |
753 | { | |
754 | struct multipath *m = (struct multipath *) ti->private; | |
755 | free_multipath(m); | |
756 | } | |
757 | ||
758 | /* | |
759 | * Map bios, recording original fields for later in case we have to resubmit | |
760 | */ | |
761 | static int multipath_map(struct dm_target *ti, struct bio *bio, | |
762 | union map_info *map_context) | |
763 | { | |
764 | int r; | |
765 | struct mpath_io *mpio; | |
766 | struct multipath *m = (struct multipath *) ti->private; | |
767 | ||
768 | mpio = mempool_alloc(m->mpio_pool, GFP_NOIO); | |
769 | dm_bio_record(&mpio->details, bio); | |
770 | ||
771 | map_context->ptr = mpio; | |
772 | bio->bi_rw |= (1 << BIO_RW_FAILFAST); | |
773 | r = map_io(m, bio, mpio, 0); | |
774 | if (r < 0) | |
775 | mempool_free(mpio, m->mpio_pool); | |
776 | ||
777 | return r; | |
778 | } | |
779 | ||
780 | /* | |
781 | * Take a path out of use. | |
782 | */ | |
783 | static int fail_path(struct pgpath *pgpath) | |
784 | { | |
785 | unsigned long flags; | |
786 | struct multipath *m = pgpath->pg->m; | |
787 | ||
788 | spin_lock_irqsave(&m->lock, flags); | |
789 | ||
790 | if (!pgpath->path.is_active) | |
791 | goto out; | |
792 | ||
793 | DMWARN("dm-multipath: Failing path %s.", pgpath->path.dev->name); | |
794 | ||
795 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
796 | pgpath->path.is_active = 0; | |
797 | pgpath->fail_count++; | |
798 | ||
799 | m->nr_valid_paths--; | |
800 | ||
801 | if (pgpath == m->current_pgpath) | |
802 | m->current_pgpath = NULL; | |
803 | ||
c557308e | 804 | queue_work(kmultipathd, &m->trigger_event); |
1da177e4 LT |
805 | |
806 | out: | |
807 | spin_unlock_irqrestore(&m->lock, flags); | |
808 | ||
809 | return 0; | |
810 | } | |
811 | ||
812 | /* | |
813 | * Reinstate a previously-failed path | |
814 | */ | |
815 | static int reinstate_path(struct pgpath *pgpath) | |
816 | { | |
817 | int r = 0; | |
818 | unsigned long flags; | |
819 | struct multipath *m = pgpath->pg->m; | |
820 | ||
821 | spin_lock_irqsave(&m->lock, flags); | |
822 | ||
823 | if (pgpath->path.is_active) | |
824 | goto out; | |
825 | ||
826 | if (!pgpath->pg->ps.type) { | |
827 | DMWARN("Reinstate path not supported by path selector %s", | |
828 | pgpath->pg->ps.type->name); | |
829 | r = -EINVAL; | |
830 | goto out; | |
831 | } | |
832 | ||
833 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
834 | if (r) | |
835 | goto out; | |
836 | ||
837 | pgpath->path.is_active = 1; | |
838 | ||
839 | m->current_pgpath = NULL; | |
840 | if (!m->nr_valid_paths++) | |
c557308e | 841 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 | 842 | |
c557308e | 843 | queue_work(kmultipathd, &m->trigger_event); |
1da177e4 LT |
844 | |
845 | out: | |
846 | spin_unlock_irqrestore(&m->lock, flags); | |
847 | ||
848 | return r; | |
849 | } | |
850 | ||
851 | /* | |
852 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
853 | */ | |
854 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
855 | action_fn action) | |
856 | { | |
857 | int r = 0; | |
858 | struct pgpath *pgpath; | |
859 | struct priority_group *pg; | |
860 | ||
861 | list_for_each_entry(pg, &m->priority_groups, list) { | |
862 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
863 | if (pgpath->path.dev == dev) | |
864 | r = action(pgpath); | |
865 | } | |
866 | } | |
867 | ||
868 | return r; | |
869 | } | |
870 | ||
871 | /* | |
872 | * Temporarily try to avoid having to use the specified PG | |
873 | */ | |
874 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
875 | int bypassed) | |
876 | { | |
877 | unsigned long flags; | |
878 | ||
879 | spin_lock_irqsave(&m->lock, flags); | |
880 | ||
881 | pg->bypassed = bypassed; | |
882 | m->current_pgpath = NULL; | |
883 | m->current_pg = NULL; | |
884 | ||
885 | spin_unlock_irqrestore(&m->lock, flags); | |
886 | ||
c557308e | 887 | queue_work(kmultipathd, &m->trigger_event); |
1da177e4 LT |
888 | } |
889 | ||
890 | /* | |
891 | * Switch to using the specified PG from the next I/O that gets mapped | |
892 | */ | |
893 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
894 | { | |
895 | struct priority_group *pg; | |
896 | unsigned pgnum; | |
897 | unsigned long flags; | |
898 | ||
899 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
900 | (pgnum > m->nr_priority_groups)) { | |
901 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
902 | return -EINVAL; | |
903 | } | |
904 | ||
905 | spin_lock_irqsave(&m->lock, flags); | |
906 | list_for_each_entry(pg, &m->priority_groups, list) { | |
907 | pg->bypassed = 0; | |
908 | if (--pgnum) | |
909 | continue; | |
910 | ||
911 | m->current_pgpath = NULL; | |
912 | m->current_pg = NULL; | |
913 | m->next_pg = pg; | |
914 | } | |
915 | spin_unlock_irqrestore(&m->lock, flags); | |
916 | ||
c557308e | 917 | queue_work(kmultipathd, &m->trigger_event); |
1da177e4 LT |
918 | return 0; |
919 | } | |
920 | ||
921 | /* | |
922 | * Set/clear bypassed status of a PG. | |
923 | * PGs are numbered upwards from 1 in the order they were declared. | |
924 | */ | |
925 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
926 | { | |
927 | struct priority_group *pg; | |
928 | unsigned pgnum; | |
929 | ||
930 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
931 | (pgnum > m->nr_priority_groups)) { | |
932 | DMWARN("invalid PG number supplied to bypass_pg"); | |
933 | return -EINVAL; | |
934 | } | |
935 | ||
936 | list_for_each_entry(pg, &m->priority_groups, list) { | |
937 | if (!--pgnum) | |
938 | break; | |
939 | } | |
940 | ||
941 | bypass_pg(m, pg, bypassed); | |
942 | return 0; | |
943 | } | |
944 | ||
945 | /* | |
946 | * pg_init must call this when it has completed its initialisation | |
947 | */ | |
948 | void dm_pg_init_complete(struct path *path, unsigned err_flags) | |
949 | { | |
950 | struct pgpath *pgpath = path_to_pgpath(path); | |
951 | struct priority_group *pg = pgpath->pg; | |
952 | struct multipath *m = pg->m; | |
953 | unsigned long flags; | |
954 | ||
955 | /* We insist on failing the path if the PG is already bypassed. */ | |
956 | if (err_flags && pg->bypassed) | |
957 | err_flags |= MP_FAIL_PATH; | |
958 | ||
959 | if (err_flags & MP_FAIL_PATH) | |
960 | fail_path(pgpath); | |
961 | ||
962 | if (err_flags & MP_BYPASS_PG) | |
963 | bypass_pg(m, pg, 1); | |
964 | ||
965 | spin_lock_irqsave(&m->lock, flags); | |
966 | if (!err_flags) | |
967 | m->queue_io = 0; | |
968 | else { | |
969 | m->current_pgpath = NULL; | |
970 | m->current_pg = NULL; | |
971 | } | |
c557308e | 972 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
973 | spin_unlock_irqrestore(&m->lock, flags); |
974 | } | |
975 | ||
976 | /* | |
977 | * end_io handling | |
978 | */ | |
979 | static int do_end_io(struct multipath *m, struct bio *bio, | |
980 | int error, struct mpath_io *mpio) | |
981 | { | |
982 | struct hw_handler *hwh = &m->hw_handler; | |
983 | unsigned err_flags = MP_FAIL_PATH; /* Default behavior */ | |
984 | ||
985 | if (!error) | |
986 | return 0; /* I/O complete */ | |
987 | ||
988 | spin_lock(&m->lock); | |
989 | if (!m->nr_valid_paths) { | |
990 | if (!m->queue_if_no_path || m->suspended) { | |
991 | spin_unlock(&m->lock); | |
992 | return -EIO; | |
993 | } else { | |
994 | spin_unlock(&m->lock); | |
995 | goto requeue; | |
996 | } | |
997 | } | |
998 | spin_unlock(&m->lock); | |
999 | ||
1000 | if (hwh->type && hwh->type->error) | |
1001 | err_flags = hwh->type->error(hwh, bio); | |
1002 | ||
1003 | if (mpio->pgpath) { | |
1004 | if (err_flags & MP_FAIL_PATH) | |
1005 | fail_path(mpio->pgpath); | |
1006 | ||
1007 | if (err_flags & MP_BYPASS_PG) | |
1008 | bypass_pg(m, mpio->pgpath->pg, 1); | |
1009 | } | |
1010 | ||
1011 | if (err_flags & MP_ERROR_IO) | |
1012 | return -EIO; | |
1013 | ||
1014 | requeue: | |
1015 | dm_bio_restore(&mpio->details, bio); | |
1016 | ||
1017 | /* queue for the daemon to resubmit or fail */ | |
1018 | spin_lock(&m->lock); | |
1019 | bio_list_add(&m->queued_ios, bio); | |
1020 | m->queue_size++; | |
1021 | if (!m->queue_io) | |
c557308e | 1022 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
1023 | spin_unlock(&m->lock); |
1024 | ||
1025 | return 1; /* io not complete */ | |
1026 | } | |
1027 | ||
1028 | static int multipath_end_io(struct dm_target *ti, struct bio *bio, | |
1029 | int error, union map_info *map_context) | |
1030 | { | |
1031 | struct multipath *m = (struct multipath *) ti->private; | |
1032 | struct mpath_io *mpio = (struct mpath_io *) map_context->ptr; | |
1033 | struct pgpath *pgpath = mpio->pgpath; | |
1034 | struct path_selector *ps; | |
1035 | int r; | |
1036 | ||
1037 | r = do_end_io(m, bio, error, mpio); | |
1038 | if (pgpath) { | |
1039 | ps = &pgpath->pg->ps; | |
1040 | if (ps->type->end_io) | |
1041 | ps->type->end_io(ps, &pgpath->path); | |
1042 | } | |
1043 | if (r <= 0) | |
1044 | mempool_free(mpio, m->mpio_pool); | |
1045 | ||
1046 | return r; | |
1047 | } | |
1048 | ||
1049 | /* | |
1050 | * Suspend can't complete until all the I/O is processed so if | |
1051 | * the last path failed we will now error any queued I/O. | |
1052 | */ | |
1053 | static void multipath_presuspend(struct dm_target *ti) | |
1054 | { | |
1055 | struct multipath *m = (struct multipath *) ti->private; | |
1056 | unsigned long flags; | |
1057 | ||
1058 | spin_lock_irqsave(&m->lock, flags); | |
1059 | m->suspended = 1; | |
1060 | if (m->queue_if_no_path) | |
c557308e | 1061 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
1062 | spin_unlock_irqrestore(&m->lock, flags); |
1063 | } | |
1064 | ||
1065 | static void multipath_resume(struct dm_target *ti) | |
1066 | { | |
1067 | struct multipath *m = (struct multipath *) ti->private; | |
1068 | unsigned long flags; | |
1069 | ||
1070 | spin_lock_irqsave(&m->lock, flags); | |
1071 | m->suspended = 0; | |
1072 | spin_unlock_irqrestore(&m->lock, flags); | |
1073 | } | |
1074 | ||
1075 | /* | |
1076 | * Info output has the following format: | |
1077 | * num_multipath_feature_args [multipath_feature_args]* | |
1078 | * num_handler_status_args [handler_status_args]* | |
1079 | * num_groups init_group_number | |
1080 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1081 | * num_paths num_selector_args | |
1082 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1083 | * | |
1084 | * Table output has the following format (identical to the constructor string): | |
1085 | * num_feature_args [features_args]* | |
1086 | * num_handler_args hw_handler [hw_handler_args]* | |
1087 | * num_groups init_group_number | |
1088 | * [priority selector-name num_ps_args [ps_args]* | |
1089 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1090 | */ | |
1091 | static int multipath_status(struct dm_target *ti, status_type_t type, | |
1092 | char *result, unsigned int maxlen) | |
1093 | { | |
1094 | int sz = 0; | |
1095 | unsigned long flags; | |
1096 | struct multipath *m = (struct multipath *) ti->private; | |
1097 | struct hw_handler *hwh = &m->hw_handler; | |
1098 | struct priority_group *pg; | |
1099 | struct pgpath *p; | |
1100 | unsigned pg_num; | |
1101 | char state; | |
1102 | ||
1103 | spin_lock_irqsave(&m->lock, flags); | |
1104 | ||
1105 | /* Features */ | |
1106 | if (type == STATUSTYPE_INFO) | |
1107 | DMEMIT("1 %u ", m->queue_size); | |
1108 | else if (m->queue_if_no_path) | |
1109 | DMEMIT("1 queue_if_no_path "); | |
1110 | else | |
1111 | DMEMIT("0 "); | |
1112 | ||
1113 | if (hwh->type && hwh->type->status) | |
1114 | sz += hwh->type->status(hwh, type, result + sz, maxlen - sz); | |
1115 | else if (!hwh->type || type == STATUSTYPE_INFO) | |
1116 | DMEMIT("0 "); | |
1117 | else | |
1118 | DMEMIT("1 %s ", hwh->type->name); | |
1119 | ||
1120 | DMEMIT("%u ", m->nr_priority_groups); | |
1121 | ||
1122 | if (m->next_pg) | |
1123 | pg_num = m->next_pg->pg_num; | |
1124 | else if (m->current_pg) | |
1125 | pg_num = m->current_pg->pg_num; | |
1126 | else | |
1127 | pg_num = 1; | |
1128 | ||
1129 | DMEMIT("%u ", pg_num); | |
1130 | ||
1131 | switch (type) { | |
1132 | case STATUSTYPE_INFO: | |
1133 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1134 | if (pg->bypassed) | |
1135 | state = 'D'; /* Disabled */ | |
1136 | else if (pg == m->current_pg) | |
1137 | state = 'A'; /* Currently Active */ | |
1138 | else | |
1139 | state = 'E'; /* Enabled */ | |
1140 | ||
1141 | DMEMIT("%c ", state); | |
1142 | ||
1143 | if (pg->ps.type->status) | |
1144 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1145 | result + sz, | |
1146 | maxlen - sz); | |
1147 | else | |
1148 | DMEMIT("0 "); | |
1149 | ||
1150 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1151 | pg->ps.type->info_args); | |
1152 | ||
1153 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1154 | DMEMIT("%s %s %u ", p->path.dev->name, | |
1155 | p->path.is_active ? "A" : "F", | |
1156 | p->fail_count); | |
1157 | if (pg->ps.type->status) | |
1158 | sz += pg->ps.type->status(&pg->ps, | |
1159 | &p->path, type, result + sz, | |
1160 | maxlen - sz); | |
1161 | } | |
1162 | } | |
1163 | break; | |
1164 | ||
1165 | case STATUSTYPE_TABLE: | |
1166 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1167 | DMEMIT("%s ", pg->ps.type->name); | |
1168 | ||
1169 | if (pg->ps.type->status) | |
1170 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1171 | result + sz, | |
1172 | maxlen - sz); | |
1173 | else | |
1174 | DMEMIT("0 "); | |
1175 | ||
1176 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1177 | pg->ps.type->table_args); | |
1178 | ||
1179 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1180 | DMEMIT("%s ", p->path.dev->name); | |
1181 | if (pg->ps.type->status) | |
1182 | sz += pg->ps.type->status(&pg->ps, | |
1183 | &p->path, type, result + sz, | |
1184 | maxlen - sz); | |
1185 | } | |
1186 | } | |
1187 | break; | |
1188 | } | |
1189 | ||
1190 | spin_unlock_irqrestore(&m->lock, flags); | |
1191 | ||
1192 | return 0; | |
1193 | } | |
1194 | ||
1195 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1196 | { | |
1197 | int r; | |
1198 | struct dm_dev *dev; | |
1199 | struct multipath *m = (struct multipath *) ti->private; | |
1200 | action_fn action; | |
1201 | ||
1202 | if (argc == 1) { | |
1203 | if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) | |
1204 | return queue_if_no_path(m, 1); | |
1205 | else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) | |
1206 | return queue_if_no_path(m, 0); | |
1207 | } | |
1208 | ||
1209 | if (argc != 2) | |
1210 | goto error; | |
1211 | ||
1212 | if (!strnicmp(argv[0], MESG_STR("disable_group"))) | |
1213 | return bypass_pg_num(m, argv[1], 1); | |
1214 | else if (!strnicmp(argv[0], MESG_STR("enable_group"))) | |
1215 | return bypass_pg_num(m, argv[1], 0); | |
1216 | else if (!strnicmp(argv[0], MESG_STR("switch_group"))) | |
1217 | return switch_pg_num(m, argv[1]); | |
1218 | else if (!strnicmp(argv[0], MESG_STR("reinstate_path"))) | |
1219 | action = reinstate_path; | |
1220 | else if (!strnicmp(argv[0], MESG_STR("fail_path"))) | |
1221 | action = fail_path; | |
1222 | else | |
1223 | goto error; | |
1224 | ||
1225 | r = dm_get_device(ti, argv[1], ti->begin, ti->len, | |
1226 | dm_table_get_mode(ti->table), &dev); | |
1227 | if (r) { | |
1228 | DMWARN("dm-multipath message: error getting device %s", | |
1229 | argv[1]); | |
1230 | return -EINVAL; | |
1231 | } | |
1232 | ||
1233 | r = action_dev(m, dev, action); | |
1234 | ||
1235 | dm_put_device(ti, dev); | |
1236 | ||
1237 | return r; | |
1238 | ||
1239 | error: | |
1240 | DMWARN("Unrecognised multipath message received."); | |
1241 | return -EINVAL; | |
1242 | } | |
1243 | ||
1244 | /*----------------------------------------------------------------- | |
1245 | * Module setup | |
1246 | *---------------------------------------------------------------*/ | |
1247 | static struct target_type multipath_target = { | |
1248 | .name = "multipath", | |
1249 | .version = {1, 0, 4}, | |
1250 | .module = THIS_MODULE, | |
1251 | .ctr = multipath_ctr, | |
1252 | .dtr = multipath_dtr, | |
1253 | .map = multipath_map, | |
1254 | .end_io = multipath_end_io, | |
1255 | .presuspend = multipath_presuspend, | |
1256 | .resume = multipath_resume, | |
1257 | .status = multipath_status, | |
1258 | .message = multipath_message, | |
1259 | }; | |
1260 | ||
1261 | static int __init dm_multipath_init(void) | |
1262 | { | |
1263 | int r; | |
1264 | ||
1265 | /* allocate a slab for the dm_ios */ | |
1266 | _mpio_cache = kmem_cache_create("dm_mpath", sizeof(struct mpath_io), | |
1267 | 0, 0, NULL, NULL); | |
1268 | if (!_mpio_cache) | |
1269 | return -ENOMEM; | |
1270 | ||
1271 | r = dm_register_target(&multipath_target); | |
1272 | if (r < 0) { | |
1273 | DMERR("%s: register failed %d", multipath_target.name, r); | |
1274 | kmem_cache_destroy(_mpio_cache); | |
1275 | return -EINVAL; | |
1276 | } | |
1277 | ||
c557308e AK |
1278 | kmultipathd = create_workqueue("kmpathd"); |
1279 | if (!kmultipathd) { | |
1280 | DMERR("%s: failed to create workqueue kmpathd", | |
1281 | multipath_target.name); | |
1282 | dm_unregister_target(&multipath_target); | |
1283 | kmem_cache_destroy(_mpio_cache); | |
1284 | return -ENOMEM; | |
1285 | } | |
1286 | ||
1da177e4 LT |
1287 | DMINFO("dm-multipath version %u.%u.%u loaded", |
1288 | multipath_target.version[0], multipath_target.version[1], | |
1289 | multipath_target.version[2]); | |
1290 | ||
1291 | return r; | |
1292 | } | |
1293 | ||
1294 | static void __exit dm_multipath_exit(void) | |
1295 | { | |
1296 | int r; | |
1297 | ||
c557308e AK |
1298 | destroy_workqueue(kmultipathd); |
1299 | ||
1da177e4 LT |
1300 | r = dm_unregister_target(&multipath_target); |
1301 | if (r < 0) | |
1302 | DMERR("%s: target unregister failed %d", | |
1303 | multipath_target.name, r); | |
1304 | kmem_cache_destroy(_mpio_cache); | |
1305 | } | |
1306 | ||
1307 | EXPORT_SYMBOL_GPL(dm_pg_init_complete); | |
1308 | ||
1309 | module_init(dm_multipath_init); | |
1310 | module_exit(dm_multipath_exit); | |
1311 | ||
1312 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1313 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1314 | MODULE_LICENSE("GPL"); |