Commit | Line | Data |
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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? */ | |
c3cd4f6b | 66 | unsigned pg_init_in_progress; /* Only one pg_init allowed at once */ |
1da177e4 LT |
67 | |
68 | unsigned nr_valid_paths; /* Total number of usable paths */ | |
69 | struct pgpath *current_pgpath; | |
70 | struct priority_group *current_pg; | |
71 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
72 | unsigned repeat_count; /* I/Os left before calling PS again */ | |
73 | ||
74 | unsigned queue_io; /* Must we queue all I/O? */ | |
75 | unsigned queue_if_no_path; /* Queue I/O if last path fails? */ | |
436d4108 | 76 | unsigned saved_queue_if_no_path;/* Saved state during suspension */ |
1da177e4 LT |
77 | |
78 | struct work_struct process_queued_ios; | |
79 | struct bio_list queued_ios; | |
80 | unsigned queue_size; | |
81 | ||
82 | struct work_struct trigger_event; | |
83 | ||
84 | /* | |
85 | * We must use a mempool of mpath_io structs so that we | |
86 | * can resubmit bios on error. | |
87 | */ | |
88 | mempool_t *mpio_pool; | |
89 | }; | |
90 | ||
91 | /* | |
92 | * Context information attached to each bio we process. | |
93 | */ | |
94 | struct mpath_io { | |
95 | struct pgpath *pgpath; | |
96 | struct dm_bio_details details; | |
97 | }; | |
98 | ||
99 | typedef int (*action_fn) (struct pgpath *pgpath); | |
100 | ||
101 | #define MIN_IOS 256 /* Mempool size */ | |
102 | ||
103 | static kmem_cache_t *_mpio_cache; | |
104 | ||
c557308e | 105 | struct workqueue_struct *kmultipathd; |
1da177e4 LT |
106 | static void process_queued_ios(void *data); |
107 | static void trigger_event(void *data); | |
108 | ||
109 | ||
110 | /*----------------------------------------------- | |
111 | * Allocation routines | |
112 | *-----------------------------------------------*/ | |
113 | ||
114 | static struct pgpath *alloc_pgpath(void) | |
115 | { | |
116 | struct pgpath *pgpath = kmalloc(sizeof(*pgpath), GFP_KERNEL); | |
117 | ||
118 | if (pgpath) { | |
119 | memset(pgpath, 0, sizeof(*pgpath)); | |
120 | pgpath->path.is_active = 1; | |
121 | } | |
122 | ||
123 | return pgpath; | |
124 | } | |
125 | ||
126 | static inline void free_pgpath(struct pgpath *pgpath) | |
127 | { | |
128 | kfree(pgpath); | |
129 | } | |
130 | ||
131 | static struct priority_group *alloc_priority_group(void) | |
132 | { | |
133 | struct priority_group *pg; | |
134 | ||
135 | pg = kmalloc(sizeof(*pg), GFP_KERNEL); | |
136 | if (!pg) | |
137 | return NULL; | |
138 | ||
139 | memset(pg, 0, sizeof(*pg)); | |
140 | INIT_LIST_HEAD(&pg->pgpaths); | |
141 | ||
142 | return pg; | |
143 | } | |
144 | ||
145 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
146 | { | |
147 | struct pgpath *pgpath, *tmp; | |
148 | ||
149 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
150 | list_del(&pgpath->list); | |
151 | dm_put_device(ti, pgpath->path.dev); | |
152 | free_pgpath(pgpath); | |
153 | } | |
154 | } | |
155 | ||
156 | static void free_priority_group(struct priority_group *pg, | |
157 | struct dm_target *ti) | |
158 | { | |
159 | struct path_selector *ps = &pg->ps; | |
160 | ||
161 | if (ps->type) { | |
162 | ps->type->destroy(ps); | |
163 | dm_put_path_selector(ps->type); | |
164 | } | |
165 | ||
166 | free_pgpaths(&pg->pgpaths, ti); | |
167 | kfree(pg); | |
168 | } | |
169 | ||
170 | static struct multipath *alloc_multipath(void) | |
171 | { | |
172 | struct multipath *m; | |
173 | ||
174 | m = kmalloc(sizeof(*m), GFP_KERNEL); | |
175 | if (m) { | |
176 | memset(m, 0, sizeof(*m)); | |
177 | INIT_LIST_HEAD(&m->priority_groups); | |
178 | spin_lock_init(&m->lock); | |
179 | m->queue_io = 1; | |
180 | INIT_WORK(&m->process_queued_ios, process_queued_ios, m); | |
181 | INIT_WORK(&m->trigger_event, trigger_event, m); | |
182 | m->mpio_pool = mempool_create(MIN_IOS, mempool_alloc_slab, | |
183 | mempool_free_slab, _mpio_cache); | |
184 | if (!m->mpio_pool) { | |
185 | kfree(m); | |
186 | return NULL; | |
187 | } | |
188 | } | |
189 | ||
190 | return m; | |
191 | } | |
192 | ||
193 | static void free_multipath(struct multipath *m) | |
194 | { | |
195 | struct priority_group *pg, *tmp; | |
196 | struct hw_handler *hwh = &m->hw_handler; | |
197 | ||
198 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
199 | list_del(&pg->list); | |
200 | free_priority_group(pg, m->ti); | |
201 | } | |
202 | ||
203 | if (hwh->type) { | |
204 | hwh->type->destroy(hwh); | |
205 | dm_put_hw_handler(hwh->type); | |
206 | } | |
207 | ||
208 | mempool_destroy(m->mpio_pool); | |
209 | kfree(m); | |
210 | } | |
211 | ||
212 | ||
213 | /*----------------------------------------------- | |
214 | * Path selection | |
215 | *-----------------------------------------------*/ | |
216 | ||
217 | static void __switch_pg(struct multipath *m, struct pgpath *pgpath) | |
218 | { | |
219 | struct hw_handler *hwh = &m->hw_handler; | |
220 | ||
221 | m->current_pg = pgpath->pg; | |
222 | ||
223 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
224 | if (hwh->type && hwh->type->pg_init) { | |
225 | m->pg_init_required = 1; | |
226 | m->queue_io = 1; | |
227 | } else { | |
228 | m->pg_init_required = 0; | |
229 | m->queue_io = 0; | |
230 | } | |
231 | } | |
232 | ||
233 | static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg) | |
234 | { | |
235 | struct path *path; | |
236 | ||
237 | path = pg->ps.type->select_path(&pg->ps, &m->repeat_count); | |
238 | if (!path) | |
239 | return -ENXIO; | |
240 | ||
241 | m->current_pgpath = path_to_pgpath(path); | |
242 | ||
243 | if (m->current_pg != pg) | |
244 | __switch_pg(m, m->current_pgpath); | |
245 | ||
246 | return 0; | |
247 | } | |
248 | ||
249 | static void __choose_pgpath(struct multipath *m) | |
250 | { | |
251 | struct priority_group *pg; | |
252 | unsigned bypassed = 1; | |
253 | ||
254 | if (!m->nr_valid_paths) | |
255 | goto failed; | |
256 | ||
257 | /* Were we instructed to switch PG? */ | |
258 | if (m->next_pg) { | |
259 | pg = m->next_pg; | |
260 | m->next_pg = NULL; | |
261 | if (!__choose_path_in_pg(m, pg)) | |
262 | return; | |
263 | } | |
264 | ||
265 | /* Don't change PG until it has no remaining paths */ | |
266 | if (m->current_pg && !__choose_path_in_pg(m, m->current_pg)) | |
267 | return; | |
268 | ||
269 | /* | |
270 | * Loop through priority groups until we find a valid path. | |
271 | * First time we skip PGs marked 'bypassed'. | |
272 | * Second time we only try the ones we skipped. | |
273 | */ | |
274 | do { | |
275 | list_for_each_entry(pg, &m->priority_groups, list) { | |
276 | if (pg->bypassed == bypassed) | |
277 | continue; | |
278 | if (!__choose_path_in_pg(m, pg)) | |
279 | return; | |
280 | } | |
281 | } while (bypassed--); | |
282 | ||
283 | failed: | |
284 | m->current_pgpath = NULL; | |
285 | m->current_pg = NULL; | |
286 | } | |
287 | ||
288 | static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio, | |
289 | unsigned was_queued) | |
290 | { | |
291 | int r = 1; | |
292 | unsigned long flags; | |
293 | struct pgpath *pgpath; | |
294 | ||
295 | spin_lock_irqsave(&m->lock, flags); | |
296 | ||
297 | /* Do we need to select a new pgpath? */ | |
298 | if (!m->current_pgpath || | |
299 | (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) | |
300 | __choose_pgpath(m); | |
301 | ||
302 | pgpath = m->current_pgpath; | |
303 | ||
304 | if (was_queued) | |
305 | m->queue_size--; | |
306 | ||
307 | if ((pgpath && m->queue_io) || | |
436d4108 | 308 | (!pgpath && m->queue_if_no_path)) { |
1da177e4 LT |
309 | /* Queue for the daemon to resubmit */ |
310 | bio_list_add(&m->queued_ios, bio); | |
311 | m->queue_size++; | |
c3cd4f6b AK |
312 | if ((m->pg_init_required && !m->pg_init_in_progress) || |
313 | !m->queue_io) | |
c557308e | 314 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
315 | pgpath = NULL; |
316 | r = 0; | |
317 | } else if (!pgpath) | |
318 | r = -EIO; /* Failed */ | |
319 | else | |
320 | bio->bi_bdev = pgpath->path.dev->bdev; | |
321 | ||
322 | mpio->pgpath = pgpath; | |
323 | ||
324 | spin_unlock_irqrestore(&m->lock, flags); | |
325 | ||
326 | return r; | |
327 | } | |
328 | ||
329 | /* | |
330 | * If we run out of usable paths, should we queue I/O or error it? | |
331 | */ | |
332 | static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path) | |
333 | { | |
334 | unsigned long flags; | |
335 | ||
336 | spin_lock_irqsave(&m->lock, flags); | |
337 | ||
436d4108 | 338 | m->saved_queue_if_no_path = m->queue_if_no_path; |
1da177e4 | 339 | m->queue_if_no_path = queue_if_no_path; |
c3cd4f6b | 340 | if (!m->queue_if_no_path && m->queue_size) |
c557308e | 341 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
342 | |
343 | spin_unlock_irqrestore(&m->lock, flags); | |
344 | ||
345 | return 0; | |
346 | } | |
347 | ||
348 | /*----------------------------------------------------------------- | |
349 | * The multipath daemon is responsible for resubmitting queued ios. | |
350 | *---------------------------------------------------------------*/ | |
351 | ||
352 | static void dispatch_queued_ios(struct multipath *m) | |
353 | { | |
354 | int r; | |
355 | unsigned long flags; | |
356 | struct bio *bio = NULL, *next; | |
357 | struct mpath_io *mpio; | |
358 | union map_info *info; | |
359 | ||
360 | spin_lock_irqsave(&m->lock, flags); | |
361 | bio = bio_list_get(&m->queued_ios); | |
362 | spin_unlock_irqrestore(&m->lock, flags); | |
363 | ||
364 | while (bio) { | |
365 | next = bio->bi_next; | |
366 | bio->bi_next = NULL; | |
367 | ||
368 | info = dm_get_mapinfo(bio); | |
369 | mpio = info->ptr; | |
370 | ||
371 | r = map_io(m, bio, mpio, 1); | |
372 | if (r < 0) | |
373 | bio_endio(bio, bio->bi_size, r); | |
374 | else if (r == 1) | |
375 | generic_make_request(bio); | |
376 | ||
377 | bio = next; | |
378 | } | |
379 | } | |
380 | ||
381 | static void process_queued_ios(void *data) | |
382 | { | |
383 | struct multipath *m = (struct multipath *) data; | |
384 | struct hw_handler *hwh = &m->hw_handler; | |
c3cd4f6b AK |
385 | struct pgpath *pgpath = NULL; |
386 | unsigned init_required = 0, must_queue = 1; | |
1da177e4 LT |
387 | unsigned long flags; |
388 | ||
389 | spin_lock_irqsave(&m->lock, flags); | |
390 | ||
c3cd4f6b AK |
391 | if (!m->queue_size) |
392 | goto out; | |
393 | ||
1da177e4 LT |
394 | if (!m->current_pgpath) |
395 | __choose_pgpath(m); | |
396 | ||
397 | pgpath = m->current_pgpath; | |
398 | ||
c3cd4f6b AK |
399 | if ((pgpath && !m->queue_io) || |
400 | (!pgpath && !m->queue_if_no_path)) | |
401 | must_queue = 0; | |
1da177e4 | 402 | |
c3cd4f6b | 403 | if (m->pg_init_required && !m->pg_init_in_progress) { |
1da177e4 | 404 | m->pg_init_required = 0; |
c3cd4f6b AK |
405 | m->pg_init_in_progress = 1; |
406 | init_required = 1; | |
407 | } | |
1da177e4 | 408 | |
c3cd4f6b | 409 | out: |
1da177e4 LT |
410 | spin_unlock_irqrestore(&m->lock, flags); |
411 | ||
412 | if (init_required) | |
413 | hwh->type->pg_init(hwh, pgpath->pg->bypassed, &pgpath->path); | |
414 | ||
415 | if (!must_queue) | |
416 | dispatch_queued_ios(m); | |
417 | } | |
418 | ||
419 | /* | |
420 | * An event is triggered whenever a path is taken out of use. | |
421 | * Includes path failure and PG bypass. | |
422 | */ | |
423 | static void trigger_event(void *data) | |
424 | { | |
425 | struct multipath *m = (struct multipath *) data; | |
426 | ||
427 | dm_table_event(m->ti->table); | |
428 | } | |
429 | ||
430 | /*----------------------------------------------------------------- | |
431 | * Constructor/argument parsing: | |
432 | * <#multipath feature args> [<arg>]* | |
433 | * <#hw_handler args> [hw_handler [<arg>]*] | |
434 | * <#priority groups> | |
435 | * <initial priority group> | |
436 | * [<selector> <#selector args> [<arg>]* | |
437 | * <#paths> <#per-path selector args> | |
438 | * [<path> [<arg>]* ]+ ]+ | |
439 | *---------------------------------------------------------------*/ | |
440 | struct param { | |
441 | unsigned min; | |
442 | unsigned max; | |
443 | char *error; | |
444 | }; | |
445 | ||
446 | #define ESTR(s) ("dm-multipath: " s) | |
447 | ||
448 | static int read_param(struct param *param, char *str, unsigned *v, char **error) | |
449 | { | |
450 | if (!str || | |
451 | (sscanf(str, "%u", v) != 1) || | |
452 | (*v < param->min) || | |
453 | (*v > param->max)) { | |
454 | *error = param->error; | |
455 | return -EINVAL; | |
456 | } | |
457 | ||
458 | return 0; | |
459 | } | |
460 | ||
461 | struct arg_set { | |
462 | unsigned argc; | |
463 | char **argv; | |
464 | }; | |
465 | ||
466 | static char *shift(struct arg_set *as) | |
467 | { | |
468 | char *r; | |
469 | ||
470 | if (as->argc) { | |
471 | as->argc--; | |
472 | r = *as->argv; | |
473 | as->argv++; | |
474 | return r; | |
475 | } | |
476 | ||
477 | return NULL; | |
478 | } | |
479 | ||
480 | static void consume(struct arg_set *as, unsigned n) | |
481 | { | |
482 | BUG_ON (as->argc < n); | |
483 | as->argc -= n; | |
484 | as->argv += n; | |
485 | } | |
486 | ||
487 | static int parse_path_selector(struct arg_set *as, struct priority_group *pg, | |
488 | struct dm_target *ti) | |
489 | { | |
490 | int r; | |
491 | struct path_selector_type *pst; | |
492 | unsigned ps_argc; | |
493 | ||
494 | static struct param _params[] = { | |
495 | {0, 1024, ESTR("invalid number of path selector args")}, | |
496 | }; | |
497 | ||
498 | pst = dm_get_path_selector(shift(as)); | |
499 | if (!pst) { | |
500 | ti->error = ESTR("unknown path selector type"); | |
501 | return -EINVAL; | |
502 | } | |
503 | ||
504 | r = read_param(_params, shift(as), &ps_argc, &ti->error); | |
505 | if (r) | |
506 | return -EINVAL; | |
507 | ||
508 | r = pst->create(&pg->ps, ps_argc, as->argv); | |
509 | if (r) { | |
510 | dm_put_path_selector(pst); | |
511 | ti->error = ESTR("path selector constructor failed"); | |
512 | return r; | |
513 | } | |
514 | ||
515 | pg->ps.type = pst; | |
516 | consume(as, ps_argc); | |
517 | ||
518 | return 0; | |
519 | } | |
520 | ||
521 | static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps, | |
522 | struct dm_target *ti) | |
523 | { | |
524 | int r; | |
525 | struct pgpath *p; | |
526 | ||
527 | /* we need at least a path arg */ | |
528 | if (as->argc < 1) { | |
529 | ti->error = ESTR("no device given"); | |
530 | return NULL; | |
531 | } | |
532 | ||
533 | p = alloc_pgpath(); | |
534 | if (!p) | |
535 | return NULL; | |
536 | ||
537 | r = dm_get_device(ti, shift(as), ti->begin, ti->len, | |
538 | dm_table_get_mode(ti->table), &p->path.dev); | |
539 | if (r) { | |
540 | ti->error = ESTR("error getting device"); | |
541 | goto bad; | |
542 | } | |
543 | ||
544 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); | |
545 | if (r) { | |
546 | dm_put_device(ti, p->path.dev); | |
547 | goto bad; | |
548 | } | |
549 | ||
550 | return p; | |
551 | ||
552 | bad: | |
553 | free_pgpath(p); | |
554 | return NULL; | |
555 | } | |
556 | ||
557 | static struct priority_group *parse_priority_group(struct arg_set *as, | |
558 | struct multipath *m, | |
559 | struct dm_target *ti) | |
560 | { | |
561 | static struct param _params[] = { | |
562 | {1, 1024, ESTR("invalid number of paths")}, | |
563 | {0, 1024, ESTR("invalid number of selector args")} | |
564 | }; | |
565 | ||
566 | int r; | |
567 | unsigned i, nr_selector_args, nr_params; | |
568 | struct priority_group *pg; | |
569 | ||
570 | if (as->argc < 2) { | |
571 | as->argc = 0; | |
572 | ti->error = ESTR("not enough priority group aruments"); | |
573 | return NULL; | |
574 | } | |
575 | ||
576 | pg = alloc_priority_group(); | |
577 | if (!pg) { | |
578 | ti->error = ESTR("couldn't allocate priority group"); | |
579 | return NULL; | |
580 | } | |
581 | pg->m = m; | |
582 | ||
583 | r = parse_path_selector(as, pg, ti); | |
584 | if (r) | |
585 | goto bad; | |
586 | ||
587 | /* | |
588 | * read the paths | |
589 | */ | |
590 | r = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error); | |
591 | if (r) | |
592 | goto bad; | |
593 | ||
594 | r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error); | |
595 | if (r) | |
596 | goto bad; | |
597 | ||
598 | nr_params = 1 + nr_selector_args; | |
599 | for (i = 0; i < pg->nr_pgpaths; i++) { | |
600 | struct pgpath *pgpath; | |
601 | struct arg_set path_args; | |
602 | ||
603 | if (as->argc < nr_params) | |
604 | goto bad; | |
605 | ||
606 | path_args.argc = nr_params; | |
607 | path_args.argv = as->argv; | |
608 | ||
609 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
610 | if (!pgpath) | |
611 | goto bad; | |
612 | ||
613 | pgpath->pg = pg; | |
614 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
615 | consume(as, nr_params); | |
616 | } | |
617 | ||
618 | return pg; | |
619 | ||
620 | bad: | |
621 | free_priority_group(pg, ti); | |
622 | return NULL; | |
623 | } | |
624 | ||
625 | static int parse_hw_handler(struct arg_set *as, struct multipath *m, | |
626 | struct dm_target *ti) | |
627 | { | |
628 | int r; | |
629 | struct hw_handler_type *hwht; | |
630 | unsigned hw_argc; | |
631 | ||
632 | static struct param _params[] = { | |
633 | {0, 1024, ESTR("invalid number of hardware handler args")}, | |
634 | }; | |
635 | ||
636 | r = read_param(_params, shift(as), &hw_argc, &ti->error); | |
637 | if (r) | |
638 | return -EINVAL; | |
639 | ||
640 | if (!hw_argc) | |
641 | return 0; | |
642 | ||
643 | hwht = dm_get_hw_handler(shift(as)); | |
644 | if (!hwht) { | |
645 | ti->error = ESTR("unknown hardware handler type"); | |
646 | return -EINVAL; | |
647 | } | |
648 | ||
649 | r = hwht->create(&m->hw_handler, hw_argc - 1, as->argv); | |
650 | if (r) { | |
651 | dm_put_hw_handler(hwht); | |
652 | ti->error = ESTR("hardware handler constructor failed"); | |
653 | return r; | |
654 | } | |
655 | ||
656 | m->hw_handler.type = hwht; | |
657 | consume(as, hw_argc - 1); | |
658 | ||
659 | return 0; | |
660 | } | |
661 | ||
662 | static int parse_features(struct arg_set *as, struct multipath *m, | |
663 | struct dm_target *ti) | |
664 | { | |
665 | int r; | |
666 | unsigned argc; | |
667 | ||
668 | static struct param _params[] = { | |
669 | {0, 1, ESTR("invalid number of feature args")}, | |
670 | }; | |
671 | ||
672 | r = read_param(_params, shift(as), &argc, &ti->error); | |
673 | if (r) | |
674 | return -EINVAL; | |
675 | ||
676 | if (!argc) | |
677 | return 0; | |
678 | ||
679 | if (!strnicmp(shift(as), MESG_STR("queue_if_no_path"))) | |
680 | return queue_if_no_path(m, 1); | |
681 | else { | |
682 | ti->error = "Unrecognised multipath feature request"; | |
683 | return -EINVAL; | |
684 | } | |
685 | } | |
686 | ||
687 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
688 | char **argv) | |
689 | { | |
690 | /* target parameters */ | |
691 | static struct param _params[] = { | |
692 | {1, 1024, ESTR("invalid number of priority groups")}, | |
693 | {1, 1024, ESTR("invalid initial priority group number")}, | |
694 | }; | |
695 | ||
696 | int r; | |
697 | struct multipath *m; | |
698 | struct arg_set as; | |
699 | unsigned pg_count = 0; | |
700 | unsigned next_pg_num; | |
701 | ||
702 | as.argc = argc; | |
703 | as.argv = argv; | |
704 | ||
705 | m = alloc_multipath(); | |
706 | if (!m) { | |
707 | ti->error = ESTR("can't allocate multipath"); | |
708 | return -EINVAL; | |
709 | } | |
710 | ||
711 | r = parse_features(&as, m, ti); | |
712 | if (r) | |
713 | goto bad; | |
714 | ||
715 | r = parse_hw_handler(&as, m, ti); | |
716 | if (r) | |
717 | goto bad; | |
718 | ||
719 | r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error); | |
720 | if (r) | |
721 | goto bad; | |
722 | ||
723 | r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error); | |
724 | if (r) | |
725 | goto bad; | |
726 | ||
727 | /* parse the priority groups */ | |
728 | while (as.argc) { | |
729 | struct priority_group *pg; | |
730 | ||
731 | pg = parse_priority_group(&as, m, ti); | |
732 | if (!pg) { | |
733 | r = -EINVAL; | |
734 | goto bad; | |
735 | } | |
736 | ||
737 | m->nr_valid_paths += pg->nr_pgpaths; | |
738 | list_add_tail(&pg->list, &m->priority_groups); | |
739 | pg_count++; | |
740 | pg->pg_num = pg_count; | |
741 | if (!--next_pg_num) | |
742 | m->next_pg = pg; | |
743 | } | |
744 | ||
745 | if (pg_count != m->nr_priority_groups) { | |
746 | ti->error = ESTR("priority group count mismatch"); | |
747 | r = -EINVAL; | |
748 | goto bad; | |
749 | } | |
750 | ||
751 | ti->private = m; | |
752 | m->ti = ti; | |
753 | ||
754 | return 0; | |
755 | ||
756 | bad: | |
757 | free_multipath(m); | |
758 | return r; | |
759 | } | |
760 | ||
761 | static void multipath_dtr(struct dm_target *ti) | |
762 | { | |
763 | struct multipath *m = (struct multipath *) ti->private; | |
a044d016 AK |
764 | |
765 | flush_workqueue(kmultipathd); | |
1da177e4 LT |
766 | free_multipath(m); |
767 | } | |
768 | ||
769 | /* | |
770 | * Map bios, recording original fields for later in case we have to resubmit | |
771 | */ | |
772 | static int multipath_map(struct dm_target *ti, struct bio *bio, | |
773 | union map_info *map_context) | |
774 | { | |
775 | int r; | |
776 | struct mpath_io *mpio; | |
777 | struct multipath *m = (struct multipath *) ti->private; | |
778 | ||
f6a80ea8 AK |
779 | if (bio_barrier(bio)) |
780 | return -EOPNOTSUPP; | |
781 | ||
1da177e4 LT |
782 | mpio = mempool_alloc(m->mpio_pool, GFP_NOIO); |
783 | dm_bio_record(&mpio->details, bio); | |
784 | ||
785 | map_context->ptr = mpio; | |
786 | bio->bi_rw |= (1 << BIO_RW_FAILFAST); | |
787 | r = map_io(m, bio, mpio, 0); | |
788 | if (r < 0) | |
789 | mempool_free(mpio, m->mpio_pool); | |
790 | ||
791 | return r; | |
792 | } | |
793 | ||
794 | /* | |
795 | * Take a path out of use. | |
796 | */ | |
797 | static int fail_path(struct pgpath *pgpath) | |
798 | { | |
799 | unsigned long flags; | |
800 | struct multipath *m = pgpath->pg->m; | |
801 | ||
802 | spin_lock_irqsave(&m->lock, flags); | |
803 | ||
804 | if (!pgpath->path.is_active) | |
805 | goto out; | |
806 | ||
807 | DMWARN("dm-multipath: Failing path %s.", pgpath->path.dev->name); | |
808 | ||
809 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
810 | pgpath->path.is_active = 0; | |
811 | pgpath->fail_count++; | |
812 | ||
813 | m->nr_valid_paths--; | |
814 | ||
815 | if (pgpath == m->current_pgpath) | |
816 | m->current_pgpath = NULL; | |
817 | ||
c557308e | 818 | queue_work(kmultipathd, &m->trigger_event); |
1da177e4 LT |
819 | |
820 | out: | |
821 | spin_unlock_irqrestore(&m->lock, flags); | |
822 | ||
823 | return 0; | |
824 | } | |
825 | ||
826 | /* | |
827 | * Reinstate a previously-failed path | |
828 | */ | |
829 | static int reinstate_path(struct pgpath *pgpath) | |
830 | { | |
831 | int r = 0; | |
832 | unsigned long flags; | |
833 | struct multipath *m = pgpath->pg->m; | |
834 | ||
835 | spin_lock_irqsave(&m->lock, flags); | |
836 | ||
837 | if (pgpath->path.is_active) | |
838 | goto out; | |
839 | ||
840 | if (!pgpath->pg->ps.type) { | |
841 | DMWARN("Reinstate path not supported by path selector %s", | |
842 | pgpath->pg->ps.type->name); | |
843 | r = -EINVAL; | |
844 | goto out; | |
845 | } | |
846 | ||
847 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
848 | if (r) | |
849 | goto out; | |
850 | ||
851 | pgpath->path.is_active = 1; | |
852 | ||
853 | m->current_pgpath = NULL; | |
c3cd4f6b | 854 | if (!m->nr_valid_paths++ && m->queue_size) |
c557308e | 855 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 | 856 | |
c557308e | 857 | queue_work(kmultipathd, &m->trigger_event); |
1da177e4 LT |
858 | |
859 | out: | |
860 | spin_unlock_irqrestore(&m->lock, flags); | |
861 | ||
862 | return r; | |
863 | } | |
864 | ||
865 | /* | |
866 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
867 | */ | |
868 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
869 | action_fn action) | |
870 | { | |
871 | int r = 0; | |
872 | struct pgpath *pgpath; | |
873 | struct priority_group *pg; | |
874 | ||
875 | list_for_each_entry(pg, &m->priority_groups, list) { | |
876 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
877 | if (pgpath->path.dev == dev) | |
878 | r = action(pgpath); | |
879 | } | |
880 | } | |
881 | ||
882 | return r; | |
883 | } | |
884 | ||
885 | /* | |
886 | * Temporarily try to avoid having to use the specified PG | |
887 | */ | |
888 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
889 | int bypassed) | |
890 | { | |
891 | unsigned long flags; | |
892 | ||
893 | spin_lock_irqsave(&m->lock, flags); | |
894 | ||
895 | pg->bypassed = bypassed; | |
896 | m->current_pgpath = NULL; | |
897 | m->current_pg = NULL; | |
898 | ||
899 | spin_unlock_irqrestore(&m->lock, flags); | |
900 | ||
c557308e | 901 | queue_work(kmultipathd, &m->trigger_event); |
1da177e4 LT |
902 | } |
903 | ||
904 | /* | |
905 | * Switch to using the specified PG from the next I/O that gets mapped | |
906 | */ | |
907 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
908 | { | |
909 | struct priority_group *pg; | |
910 | unsigned pgnum; | |
911 | unsigned long flags; | |
912 | ||
913 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
914 | (pgnum > m->nr_priority_groups)) { | |
915 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
916 | return -EINVAL; | |
917 | } | |
918 | ||
919 | spin_lock_irqsave(&m->lock, flags); | |
920 | list_for_each_entry(pg, &m->priority_groups, list) { | |
921 | pg->bypassed = 0; | |
922 | if (--pgnum) | |
923 | continue; | |
924 | ||
925 | m->current_pgpath = NULL; | |
926 | m->current_pg = NULL; | |
927 | m->next_pg = pg; | |
928 | } | |
929 | spin_unlock_irqrestore(&m->lock, flags); | |
930 | ||
c557308e | 931 | queue_work(kmultipathd, &m->trigger_event); |
1da177e4 LT |
932 | return 0; |
933 | } | |
934 | ||
935 | /* | |
936 | * Set/clear bypassed status of a PG. | |
937 | * PGs are numbered upwards from 1 in the order they were declared. | |
938 | */ | |
939 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
940 | { | |
941 | struct priority_group *pg; | |
942 | unsigned pgnum; | |
943 | ||
944 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
945 | (pgnum > m->nr_priority_groups)) { | |
946 | DMWARN("invalid PG number supplied to bypass_pg"); | |
947 | return -EINVAL; | |
948 | } | |
949 | ||
950 | list_for_each_entry(pg, &m->priority_groups, list) { | |
951 | if (!--pgnum) | |
952 | break; | |
953 | } | |
954 | ||
955 | bypass_pg(m, pg, bypassed); | |
956 | return 0; | |
957 | } | |
958 | ||
959 | /* | |
960 | * pg_init must call this when it has completed its initialisation | |
961 | */ | |
962 | void dm_pg_init_complete(struct path *path, unsigned err_flags) | |
963 | { | |
964 | struct pgpath *pgpath = path_to_pgpath(path); | |
965 | struct priority_group *pg = pgpath->pg; | |
966 | struct multipath *m = pg->m; | |
967 | unsigned long flags; | |
968 | ||
969 | /* We insist on failing the path if the PG is already bypassed. */ | |
970 | if (err_flags && pg->bypassed) | |
971 | err_flags |= MP_FAIL_PATH; | |
972 | ||
973 | if (err_flags & MP_FAIL_PATH) | |
974 | fail_path(pgpath); | |
975 | ||
976 | if (err_flags & MP_BYPASS_PG) | |
977 | bypass_pg(m, pg, 1); | |
978 | ||
979 | spin_lock_irqsave(&m->lock, flags); | |
c3cd4f6b | 980 | if (err_flags) { |
1da177e4 LT |
981 | m->current_pgpath = NULL; |
982 | m->current_pg = NULL; | |
c3cd4f6b AK |
983 | } else if (!m->pg_init_required) |
984 | m->queue_io = 0; | |
985 | ||
986 | m->pg_init_in_progress = 0; | |
c557308e | 987 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
988 | spin_unlock_irqrestore(&m->lock, flags); |
989 | } | |
990 | ||
991 | /* | |
992 | * end_io handling | |
993 | */ | |
994 | static int do_end_io(struct multipath *m, struct bio *bio, | |
995 | int error, struct mpath_io *mpio) | |
996 | { | |
997 | struct hw_handler *hwh = &m->hw_handler; | |
998 | unsigned err_flags = MP_FAIL_PATH; /* Default behavior */ | |
999 | ||
1000 | if (!error) | |
1001 | return 0; /* I/O complete */ | |
1002 | ||
4f58802f LMB |
1003 | if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio)) |
1004 | return error; | |
1005 | ||
f6a80ea8 AK |
1006 | if (error == -EOPNOTSUPP) |
1007 | return error; | |
1008 | ||
1da177e4 LT |
1009 | spin_lock(&m->lock); |
1010 | if (!m->nr_valid_paths) { | |
436d4108 | 1011 | if (!m->queue_if_no_path) { |
1da177e4 LT |
1012 | spin_unlock(&m->lock); |
1013 | return -EIO; | |
1014 | } else { | |
1015 | spin_unlock(&m->lock); | |
1016 | goto requeue; | |
1017 | } | |
1018 | } | |
1019 | spin_unlock(&m->lock); | |
1020 | ||
1021 | if (hwh->type && hwh->type->error) | |
1022 | err_flags = hwh->type->error(hwh, bio); | |
1023 | ||
1024 | if (mpio->pgpath) { | |
1025 | if (err_flags & MP_FAIL_PATH) | |
1026 | fail_path(mpio->pgpath); | |
1027 | ||
1028 | if (err_flags & MP_BYPASS_PG) | |
1029 | bypass_pg(m, mpio->pgpath->pg, 1); | |
1030 | } | |
1031 | ||
1032 | if (err_flags & MP_ERROR_IO) | |
1033 | return -EIO; | |
1034 | ||
1035 | requeue: | |
1036 | dm_bio_restore(&mpio->details, bio); | |
1037 | ||
1038 | /* queue for the daemon to resubmit or fail */ | |
1039 | spin_lock(&m->lock); | |
1040 | bio_list_add(&m->queued_ios, bio); | |
1041 | m->queue_size++; | |
1042 | if (!m->queue_io) | |
c557308e | 1043 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
1044 | spin_unlock(&m->lock); |
1045 | ||
1046 | return 1; /* io not complete */ | |
1047 | } | |
1048 | ||
1049 | static int multipath_end_io(struct dm_target *ti, struct bio *bio, | |
1050 | int error, union map_info *map_context) | |
1051 | { | |
1052 | struct multipath *m = (struct multipath *) ti->private; | |
1053 | struct mpath_io *mpio = (struct mpath_io *) map_context->ptr; | |
1054 | struct pgpath *pgpath = mpio->pgpath; | |
1055 | struct path_selector *ps; | |
1056 | int r; | |
1057 | ||
1058 | r = do_end_io(m, bio, error, mpio); | |
1059 | if (pgpath) { | |
1060 | ps = &pgpath->pg->ps; | |
1061 | if (ps->type->end_io) | |
1062 | ps->type->end_io(ps, &pgpath->path); | |
1063 | } | |
1064 | if (r <= 0) | |
1065 | mempool_free(mpio, m->mpio_pool); | |
1066 | ||
1067 | return r; | |
1068 | } | |
1069 | ||
1070 | /* | |
1071 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1072 | * the last path fails we must error any remaining I/O. |
1073 | * Note that if the freeze_bdev fails while suspending, the | |
1074 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1075 | */ |
1076 | static void multipath_presuspend(struct dm_target *ti) | |
1077 | { | |
1078 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 | 1079 | |
436d4108 | 1080 | queue_if_no_path(m, 0); |
1da177e4 LT |
1081 | } |
1082 | ||
436d4108 AK |
1083 | /* |
1084 | * Restore the queue_if_no_path setting. | |
1085 | */ | |
1da177e4 LT |
1086 | static void multipath_resume(struct dm_target *ti) |
1087 | { | |
1088 | struct multipath *m = (struct multipath *) ti->private; | |
1089 | unsigned long flags; | |
1090 | ||
1091 | spin_lock_irqsave(&m->lock, flags); | |
436d4108 | 1092 | m->queue_if_no_path = m->saved_queue_if_no_path; |
1da177e4 LT |
1093 | spin_unlock_irqrestore(&m->lock, flags); |
1094 | } | |
1095 | ||
1096 | /* | |
1097 | * Info output has the following format: | |
1098 | * num_multipath_feature_args [multipath_feature_args]* | |
1099 | * num_handler_status_args [handler_status_args]* | |
1100 | * num_groups init_group_number | |
1101 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1102 | * num_paths num_selector_args | |
1103 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1104 | * | |
1105 | * Table output has the following format (identical to the constructor string): | |
1106 | * num_feature_args [features_args]* | |
1107 | * num_handler_args hw_handler [hw_handler_args]* | |
1108 | * num_groups init_group_number | |
1109 | * [priority selector-name num_ps_args [ps_args]* | |
1110 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1111 | */ | |
1112 | static int multipath_status(struct dm_target *ti, status_type_t type, | |
1113 | char *result, unsigned int maxlen) | |
1114 | { | |
1115 | int sz = 0; | |
1116 | unsigned long flags; | |
1117 | struct multipath *m = (struct multipath *) ti->private; | |
1118 | struct hw_handler *hwh = &m->hw_handler; | |
1119 | struct priority_group *pg; | |
1120 | struct pgpath *p; | |
1121 | unsigned pg_num; | |
1122 | char state; | |
1123 | ||
1124 | spin_lock_irqsave(&m->lock, flags); | |
1125 | ||
1126 | /* Features */ | |
1127 | if (type == STATUSTYPE_INFO) | |
1128 | DMEMIT("1 %u ", m->queue_size); | |
1129 | else if (m->queue_if_no_path) | |
1130 | DMEMIT("1 queue_if_no_path "); | |
1131 | else | |
1132 | DMEMIT("0 "); | |
1133 | ||
1134 | if (hwh->type && hwh->type->status) | |
1135 | sz += hwh->type->status(hwh, type, result + sz, maxlen - sz); | |
1136 | else if (!hwh->type || type == STATUSTYPE_INFO) | |
1137 | DMEMIT("0 "); | |
1138 | else | |
1139 | DMEMIT("1 %s ", hwh->type->name); | |
1140 | ||
1141 | DMEMIT("%u ", m->nr_priority_groups); | |
1142 | ||
1143 | if (m->next_pg) | |
1144 | pg_num = m->next_pg->pg_num; | |
1145 | else if (m->current_pg) | |
1146 | pg_num = m->current_pg->pg_num; | |
1147 | else | |
1148 | pg_num = 1; | |
1149 | ||
1150 | DMEMIT("%u ", pg_num); | |
1151 | ||
1152 | switch (type) { | |
1153 | case STATUSTYPE_INFO: | |
1154 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1155 | if (pg->bypassed) | |
1156 | state = 'D'; /* Disabled */ | |
1157 | else if (pg == m->current_pg) | |
1158 | state = 'A'; /* Currently Active */ | |
1159 | else | |
1160 | state = 'E'; /* Enabled */ | |
1161 | ||
1162 | DMEMIT("%c ", state); | |
1163 | ||
1164 | if (pg->ps.type->status) | |
1165 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1166 | result + sz, | |
1167 | maxlen - sz); | |
1168 | else | |
1169 | DMEMIT("0 "); | |
1170 | ||
1171 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1172 | pg->ps.type->info_args); | |
1173 | ||
1174 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1175 | DMEMIT("%s %s %u ", p->path.dev->name, | |
1176 | p->path.is_active ? "A" : "F", | |
1177 | p->fail_count); | |
1178 | if (pg->ps.type->status) | |
1179 | sz += pg->ps.type->status(&pg->ps, | |
1180 | &p->path, type, result + sz, | |
1181 | maxlen - sz); | |
1182 | } | |
1183 | } | |
1184 | break; | |
1185 | ||
1186 | case STATUSTYPE_TABLE: | |
1187 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1188 | DMEMIT("%s ", pg->ps.type->name); | |
1189 | ||
1190 | if (pg->ps.type->status) | |
1191 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1192 | result + sz, | |
1193 | maxlen - sz); | |
1194 | else | |
1195 | DMEMIT("0 "); | |
1196 | ||
1197 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1198 | pg->ps.type->table_args); | |
1199 | ||
1200 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1201 | DMEMIT("%s ", p->path.dev->name); | |
1202 | if (pg->ps.type->status) | |
1203 | sz += pg->ps.type->status(&pg->ps, | |
1204 | &p->path, type, result + sz, | |
1205 | maxlen - sz); | |
1206 | } | |
1207 | } | |
1208 | break; | |
1209 | } | |
1210 | ||
1211 | spin_unlock_irqrestore(&m->lock, flags); | |
1212 | ||
1213 | return 0; | |
1214 | } | |
1215 | ||
1216 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1217 | { | |
1218 | int r; | |
1219 | struct dm_dev *dev; | |
1220 | struct multipath *m = (struct multipath *) ti->private; | |
1221 | action_fn action; | |
1222 | ||
1223 | if (argc == 1) { | |
1224 | if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) | |
1225 | return queue_if_no_path(m, 1); | |
1226 | else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) | |
1227 | return queue_if_no_path(m, 0); | |
1228 | } | |
1229 | ||
1230 | if (argc != 2) | |
1231 | goto error; | |
1232 | ||
1233 | if (!strnicmp(argv[0], MESG_STR("disable_group"))) | |
1234 | return bypass_pg_num(m, argv[1], 1); | |
1235 | else if (!strnicmp(argv[0], MESG_STR("enable_group"))) | |
1236 | return bypass_pg_num(m, argv[1], 0); | |
1237 | else if (!strnicmp(argv[0], MESG_STR("switch_group"))) | |
1238 | return switch_pg_num(m, argv[1]); | |
1239 | else if (!strnicmp(argv[0], MESG_STR("reinstate_path"))) | |
1240 | action = reinstate_path; | |
1241 | else if (!strnicmp(argv[0], MESG_STR("fail_path"))) | |
1242 | action = fail_path; | |
1243 | else | |
1244 | goto error; | |
1245 | ||
1246 | r = dm_get_device(ti, argv[1], ti->begin, ti->len, | |
1247 | dm_table_get_mode(ti->table), &dev); | |
1248 | if (r) { | |
1249 | DMWARN("dm-multipath message: error getting device %s", | |
1250 | argv[1]); | |
1251 | return -EINVAL; | |
1252 | } | |
1253 | ||
1254 | r = action_dev(m, dev, action); | |
1255 | ||
1256 | dm_put_device(ti, dev); | |
1257 | ||
1258 | return r; | |
1259 | ||
1260 | error: | |
1261 | DMWARN("Unrecognised multipath message received."); | |
1262 | return -EINVAL; | |
1263 | } | |
1264 | ||
1265 | /*----------------------------------------------------------------- | |
1266 | * Module setup | |
1267 | *---------------------------------------------------------------*/ | |
1268 | static struct target_type multipath_target = { | |
1269 | .name = "multipath", | |
1270 | .version = {1, 0, 4}, | |
1271 | .module = THIS_MODULE, | |
1272 | .ctr = multipath_ctr, | |
1273 | .dtr = multipath_dtr, | |
1274 | .map = multipath_map, | |
1275 | .end_io = multipath_end_io, | |
1276 | .presuspend = multipath_presuspend, | |
1277 | .resume = multipath_resume, | |
1278 | .status = multipath_status, | |
1279 | .message = multipath_message, | |
1280 | }; | |
1281 | ||
1282 | static int __init dm_multipath_init(void) | |
1283 | { | |
1284 | int r; | |
1285 | ||
1286 | /* allocate a slab for the dm_ios */ | |
1287 | _mpio_cache = kmem_cache_create("dm_mpath", sizeof(struct mpath_io), | |
1288 | 0, 0, NULL, NULL); | |
1289 | if (!_mpio_cache) | |
1290 | return -ENOMEM; | |
1291 | ||
1292 | r = dm_register_target(&multipath_target); | |
1293 | if (r < 0) { | |
1294 | DMERR("%s: register failed %d", multipath_target.name, r); | |
1295 | kmem_cache_destroy(_mpio_cache); | |
1296 | return -EINVAL; | |
1297 | } | |
1298 | ||
c557308e AK |
1299 | kmultipathd = create_workqueue("kmpathd"); |
1300 | if (!kmultipathd) { | |
1301 | DMERR("%s: failed to create workqueue kmpathd", | |
1302 | multipath_target.name); | |
1303 | dm_unregister_target(&multipath_target); | |
1304 | kmem_cache_destroy(_mpio_cache); | |
1305 | return -ENOMEM; | |
1306 | } | |
1307 | ||
1da177e4 LT |
1308 | DMINFO("dm-multipath version %u.%u.%u loaded", |
1309 | multipath_target.version[0], multipath_target.version[1], | |
1310 | multipath_target.version[2]); | |
1311 | ||
1312 | return r; | |
1313 | } | |
1314 | ||
1315 | static void __exit dm_multipath_exit(void) | |
1316 | { | |
1317 | int r; | |
1318 | ||
c557308e AK |
1319 | destroy_workqueue(kmultipathd); |
1320 | ||
1da177e4 LT |
1321 | r = dm_unregister_target(&multipath_target); |
1322 | if (r < 0) | |
1323 | DMERR("%s: target unregister failed %d", | |
1324 | multipath_target.name, r); | |
1325 | kmem_cache_destroy(_mpio_cache); | |
1326 | } | |
1327 | ||
1328 | EXPORT_SYMBOL_GPL(dm_pg_init_complete); | |
1329 | ||
1330 | module_init(dm_multipath_init); | |
1331 | module_exit(dm_multipath_exit); | |
1332 | ||
1333 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1334 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1335 | MODULE_LICENSE("GPL"); |