Commit | Line | Data |
---|---|---|
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 | ||
586e80e6 MP |
8 | #include <linux/device-mapper.h> |
9 | ||
1da177e4 | 10 | #include "dm-path-selector.h" |
b15546f9 | 11 | #include "dm-uevent.h" |
1da177e4 LT |
12 | |
13 | #include <linux/ctype.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/pagemap.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/time.h> | |
20 | #include <linux/workqueue.h> | |
cfae5c9b | 21 | #include <scsi/scsi_dh.h> |
1da177e4 LT |
22 | #include <asm/atomic.h> |
23 | ||
72d94861 | 24 | #define DM_MSG_PREFIX "multipath" |
1da177e4 LT |
25 | #define MESG_STR(x) x, sizeof(x) |
26 | ||
27 | /* Path properties */ | |
28 | struct pgpath { | |
29 | struct list_head list; | |
30 | ||
31 | struct priority_group *pg; /* Owning PG */ | |
6680073d | 32 | unsigned is_active; /* Path status */ |
1da177e4 LT |
33 | unsigned fail_count; /* Cumulative failure count */ |
34 | ||
c922d5f7 | 35 | struct dm_path path; |
224cb3e9 | 36 | struct work_struct deactivate_path; |
e54f77dd | 37 | struct work_struct activate_path; |
1da177e4 LT |
38 | }; |
39 | ||
40 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
41 | ||
42 | /* | |
43 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
44 | * Each has a path selector which controls which path gets used. | |
45 | */ | |
46 | struct priority_group { | |
47 | struct list_head list; | |
48 | ||
49 | struct multipath *m; /* Owning multipath instance */ | |
50 | struct path_selector ps; | |
51 | ||
52 | unsigned pg_num; /* Reference number */ | |
53 | unsigned bypassed; /* Temporarily bypass this PG? */ | |
54 | ||
55 | unsigned nr_pgpaths; /* Number of paths in PG */ | |
56 | struct list_head pgpaths; | |
57 | }; | |
58 | ||
59 | /* Multipath context */ | |
60 | struct multipath { | |
61 | struct list_head list; | |
62 | struct dm_target *ti; | |
63 | ||
64 | spinlock_t lock; | |
65 | ||
cfae5c9b | 66 | const char *hw_handler_name; |
2bfd2e13 | 67 | char *hw_handler_params; |
1da177e4 LT |
68 | unsigned nr_priority_groups; |
69 | struct list_head priority_groups; | |
70 | unsigned pg_init_required; /* pg_init needs calling? */ | |
c3cd4f6b | 71 | unsigned pg_init_in_progress; /* Only one pg_init allowed at once */ |
2bded7bd | 72 | wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ |
1da177e4 LT |
73 | |
74 | unsigned nr_valid_paths; /* Total number of usable paths */ | |
75 | struct pgpath *current_pgpath; | |
76 | struct priority_group *current_pg; | |
77 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
78 | unsigned repeat_count; /* I/Os left before calling PS again */ | |
79 | ||
80 | unsigned queue_io; /* Must we queue all I/O? */ | |
81 | unsigned queue_if_no_path; /* Queue I/O if last path fails? */ | |
436d4108 | 82 | unsigned saved_queue_if_no_path;/* Saved state during suspension */ |
c9e45581 DW |
83 | unsigned pg_init_retries; /* Number of times to retry pg_init */ |
84 | unsigned pg_init_count; /* Number of times pg_init called */ | |
1da177e4 LT |
85 | |
86 | struct work_struct process_queued_ios; | |
f40c67f0 | 87 | struct list_head queued_ios; |
1da177e4 LT |
88 | unsigned queue_size; |
89 | ||
90 | struct work_struct trigger_event; | |
91 | ||
92 | /* | |
028867ac | 93 | * We must use a mempool of dm_mpath_io structs so that we |
1da177e4 LT |
94 | * can resubmit bios on error. |
95 | */ | |
96 | mempool_t *mpio_pool; | |
6380f26f MA |
97 | |
98 | struct mutex work_mutex; | |
1da177e4 LT |
99 | }; |
100 | ||
101 | /* | |
102 | * Context information attached to each bio we process. | |
103 | */ | |
028867ac | 104 | struct dm_mpath_io { |
1da177e4 | 105 | struct pgpath *pgpath; |
02ab823f | 106 | size_t nr_bytes; |
1da177e4 LT |
107 | }; |
108 | ||
109 | typedef int (*action_fn) (struct pgpath *pgpath); | |
110 | ||
111 | #define MIN_IOS 256 /* Mempool size */ | |
112 | ||
e18b890b | 113 | static struct kmem_cache *_mpio_cache; |
1da177e4 | 114 | |
bab7cfc7 | 115 | static struct workqueue_struct *kmultipathd, *kmpath_handlerd; |
c4028958 DH |
116 | static void process_queued_ios(struct work_struct *work); |
117 | static void trigger_event(struct work_struct *work); | |
bab7cfc7 | 118 | static void activate_path(struct work_struct *work); |
224cb3e9 | 119 | static void deactivate_path(struct work_struct *work); |
1da177e4 LT |
120 | |
121 | ||
122 | /*----------------------------------------------- | |
123 | * Allocation routines | |
124 | *-----------------------------------------------*/ | |
125 | ||
126 | static struct pgpath *alloc_pgpath(void) | |
127 | { | |
e69fae56 | 128 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); |
1da177e4 | 129 | |
224cb3e9 | 130 | if (pgpath) { |
6680073d | 131 | pgpath->is_active = 1; |
224cb3e9 | 132 | INIT_WORK(&pgpath->deactivate_path, deactivate_path); |
e54f77dd | 133 | INIT_WORK(&pgpath->activate_path, activate_path); |
224cb3e9 | 134 | } |
1da177e4 LT |
135 | |
136 | return pgpath; | |
137 | } | |
138 | ||
028867ac | 139 | static void free_pgpath(struct pgpath *pgpath) |
1da177e4 LT |
140 | { |
141 | kfree(pgpath); | |
142 | } | |
143 | ||
224cb3e9 MA |
144 | static void deactivate_path(struct work_struct *work) |
145 | { | |
146 | struct pgpath *pgpath = | |
147 | container_of(work, struct pgpath, deactivate_path); | |
148 | ||
149 | blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue); | |
150 | } | |
151 | ||
1da177e4 LT |
152 | static struct priority_group *alloc_priority_group(void) |
153 | { | |
154 | struct priority_group *pg; | |
155 | ||
e69fae56 | 156 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); |
1da177e4 | 157 | |
e69fae56 MM |
158 | if (pg) |
159 | INIT_LIST_HEAD(&pg->pgpaths); | |
1da177e4 LT |
160 | |
161 | return pg; | |
162 | } | |
163 | ||
164 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
165 | { | |
166 | struct pgpath *pgpath, *tmp; | |
ae11b1b3 | 167 | struct multipath *m = ti->private; |
1da177e4 LT |
168 | |
169 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
170 | list_del(&pgpath->list); | |
ae11b1b3 HR |
171 | if (m->hw_handler_name) |
172 | scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev)); | |
1da177e4 LT |
173 | dm_put_device(ti, pgpath->path.dev); |
174 | free_pgpath(pgpath); | |
175 | } | |
176 | } | |
177 | ||
178 | static void free_priority_group(struct priority_group *pg, | |
179 | struct dm_target *ti) | |
180 | { | |
181 | struct path_selector *ps = &pg->ps; | |
182 | ||
183 | if (ps->type) { | |
184 | ps->type->destroy(ps); | |
185 | dm_put_path_selector(ps->type); | |
186 | } | |
187 | ||
188 | free_pgpaths(&pg->pgpaths, ti); | |
189 | kfree(pg); | |
190 | } | |
191 | ||
28f16c20 | 192 | static struct multipath *alloc_multipath(struct dm_target *ti) |
1da177e4 LT |
193 | { |
194 | struct multipath *m; | |
195 | ||
e69fae56 | 196 | m = kzalloc(sizeof(*m), GFP_KERNEL); |
1da177e4 | 197 | if (m) { |
1da177e4 | 198 | INIT_LIST_HEAD(&m->priority_groups); |
f40c67f0 | 199 | INIT_LIST_HEAD(&m->queued_ios); |
1da177e4 LT |
200 | spin_lock_init(&m->lock); |
201 | m->queue_io = 1; | |
c4028958 DH |
202 | INIT_WORK(&m->process_queued_ios, process_queued_ios); |
203 | INIT_WORK(&m->trigger_event, trigger_event); | |
2bded7bd | 204 | init_waitqueue_head(&m->pg_init_wait); |
6380f26f | 205 | mutex_init(&m->work_mutex); |
93d2341c | 206 | m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache); |
1da177e4 LT |
207 | if (!m->mpio_pool) { |
208 | kfree(m); | |
209 | return NULL; | |
210 | } | |
28f16c20 MM |
211 | m->ti = ti; |
212 | ti->private = m; | |
1da177e4 LT |
213 | } |
214 | ||
215 | return m; | |
216 | } | |
217 | ||
218 | static void free_multipath(struct multipath *m) | |
219 | { | |
220 | struct priority_group *pg, *tmp; | |
1da177e4 LT |
221 | |
222 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
223 | list_del(&pg->list); | |
224 | free_priority_group(pg, m->ti); | |
225 | } | |
226 | ||
cfae5c9b | 227 | kfree(m->hw_handler_name); |
2bfd2e13 | 228 | kfree(m->hw_handler_params); |
1da177e4 LT |
229 | mempool_destroy(m->mpio_pool); |
230 | kfree(m); | |
231 | } | |
232 | ||
233 | ||
234 | /*----------------------------------------------- | |
235 | * Path selection | |
236 | *-----------------------------------------------*/ | |
237 | ||
fb612642 KU |
238 | static void __pg_init_all_paths(struct multipath *m) |
239 | { | |
240 | struct pgpath *pgpath; | |
241 | ||
242 | m->pg_init_count++; | |
243 | m->pg_init_required = 0; | |
244 | list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) { | |
245 | /* Skip failed paths */ | |
246 | if (!pgpath->is_active) | |
247 | continue; | |
248 | if (queue_work(kmpath_handlerd, &pgpath->activate_path)) | |
249 | m->pg_init_in_progress++; | |
250 | } | |
251 | } | |
252 | ||
1da177e4 LT |
253 | static void __switch_pg(struct multipath *m, struct pgpath *pgpath) |
254 | { | |
1da177e4 LT |
255 | m->current_pg = pgpath->pg; |
256 | ||
257 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
cfae5c9b | 258 | if (m->hw_handler_name) { |
1da177e4 LT |
259 | m->pg_init_required = 1; |
260 | m->queue_io = 1; | |
261 | } else { | |
262 | m->pg_init_required = 0; | |
263 | m->queue_io = 0; | |
264 | } | |
c9e45581 DW |
265 | |
266 | m->pg_init_count = 0; | |
1da177e4 LT |
267 | } |
268 | ||
02ab823f KU |
269 | static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg, |
270 | size_t nr_bytes) | |
1da177e4 | 271 | { |
c922d5f7 | 272 | struct dm_path *path; |
1da177e4 | 273 | |
02ab823f | 274 | path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes); |
1da177e4 LT |
275 | if (!path) |
276 | return -ENXIO; | |
277 | ||
278 | m->current_pgpath = path_to_pgpath(path); | |
279 | ||
280 | if (m->current_pg != pg) | |
281 | __switch_pg(m, m->current_pgpath); | |
282 | ||
283 | return 0; | |
284 | } | |
285 | ||
02ab823f | 286 | static void __choose_pgpath(struct multipath *m, size_t nr_bytes) |
1da177e4 LT |
287 | { |
288 | struct priority_group *pg; | |
289 | unsigned bypassed = 1; | |
290 | ||
291 | if (!m->nr_valid_paths) | |
292 | goto failed; | |
293 | ||
294 | /* Were we instructed to switch PG? */ | |
295 | if (m->next_pg) { | |
296 | pg = m->next_pg; | |
297 | m->next_pg = NULL; | |
02ab823f | 298 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
299 | return; |
300 | } | |
301 | ||
302 | /* Don't change PG until it has no remaining paths */ | |
02ab823f | 303 | if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes)) |
1da177e4 LT |
304 | return; |
305 | ||
306 | /* | |
307 | * Loop through priority groups until we find a valid path. | |
308 | * First time we skip PGs marked 'bypassed'. | |
309 | * Second time we only try the ones we skipped. | |
310 | */ | |
311 | do { | |
312 | list_for_each_entry(pg, &m->priority_groups, list) { | |
313 | if (pg->bypassed == bypassed) | |
314 | continue; | |
02ab823f | 315 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
316 | return; |
317 | } | |
318 | } while (bypassed--); | |
319 | ||
320 | failed: | |
321 | m->current_pgpath = NULL; | |
322 | m->current_pg = NULL; | |
323 | } | |
324 | ||
45e15720 KU |
325 | /* |
326 | * Check whether bios must be queued in the device-mapper core rather | |
327 | * than here in the target. | |
328 | * | |
329 | * m->lock must be held on entry. | |
330 | * | |
331 | * If m->queue_if_no_path and m->saved_queue_if_no_path hold the | |
332 | * same value then we are not between multipath_presuspend() | |
333 | * and multipath_resume() calls and we have no need to check | |
334 | * for the DMF_NOFLUSH_SUSPENDING flag. | |
335 | */ | |
336 | static int __must_push_back(struct multipath *m) | |
337 | { | |
338 | return (m->queue_if_no_path != m->saved_queue_if_no_path && | |
339 | dm_noflush_suspending(m->ti)); | |
340 | } | |
341 | ||
f40c67f0 | 342 | static int map_io(struct multipath *m, struct request *clone, |
028867ac | 343 | struct dm_mpath_io *mpio, unsigned was_queued) |
1da177e4 | 344 | { |
d2a7ad29 | 345 | int r = DM_MAPIO_REMAPPED; |
f40c67f0 | 346 | size_t nr_bytes = blk_rq_bytes(clone); |
1da177e4 LT |
347 | unsigned long flags; |
348 | struct pgpath *pgpath; | |
f40c67f0 | 349 | struct block_device *bdev; |
1da177e4 LT |
350 | |
351 | spin_lock_irqsave(&m->lock, flags); | |
352 | ||
353 | /* Do we need to select a new pgpath? */ | |
354 | if (!m->current_pgpath || | |
355 | (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) | |
02ab823f | 356 | __choose_pgpath(m, nr_bytes); |
1da177e4 LT |
357 | |
358 | pgpath = m->current_pgpath; | |
359 | ||
360 | if (was_queued) | |
361 | m->queue_size--; | |
362 | ||
363 | if ((pgpath && m->queue_io) || | |
436d4108 | 364 | (!pgpath && m->queue_if_no_path)) { |
1da177e4 | 365 | /* Queue for the daemon to resubmit */ |
f40c67f0 | 366 | list_add_tail(&clone->queuelist, &m->queued_ios); |
1da177e4 | 367 | m->queue_size++; |
c3cd4f6b AK |
368 | if ((m->pg_init_required && !m->pg_init_in_progress) || |
369 | !m->queue_io) | |
c557308e | 370 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 | 371 | pgpath = NULL; |
d2a7ad29 | 372 | r = DM_MAPIO_SUBMITTED; |
f40c67f0 KU |
373 | } else if (pgpath) { |
374 | bdev = pgpath->path.dev->bdev; | |
375 | clone->q = bdev_get_queue(bdev); | |
376 | clone->rq_disk = bdev->bd_disk; | |
377 | } else if (__must_push_back(m)) | |
45e15720 KU |
378 | r = DM_MAPIO_REQUEUE; |
379 | else | |
380 | r = -EIO; /* Failed */ | |
1da177e4 LT |
381 | |
382 | mpio->pgpath = pgpath; | |
02ab823f KU |
383 | mpio->nr_bytes = nr_bytes; |
384 | ||
385 | if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io) | |
386 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path, | |
387 | nr_bytes); | |
1da177e4 LT |
388 | |
389 | spin_unlock_irqrestore(&m->lock, flags); | |
390 | ||
391 | return r; | |
392 | } | |
393 | ||
394 | /* | |
395 | * If we run out of usable paths, should we queue I/O or error it? | |
396 | */ | |
485ef69e AK |
397 | static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path, |
398 | unsigned save_old_value) | |
1da177e4 LT |
399 | { |
400 | unsigned long flags; | |
401 | ||
402 | spin_lock_irqsave(&m->lock, flags); | |
403 | ||
485ef69e AK |
404 | if (save_old_value) |
405 | m->saved_queue_if_no_path = m->queue_if_no_path; | |
406 | else | |
407 | m->saved_queue_if_no_path = queue_if_no_path; | |
1da177e4 | 408 | m->queue_if_no_path = queue_if_no_path; |
c3cd4f6b | 409 | if (!m->queue_if_no_path && m->queue_size) |
c557308e | 410 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
411 | |
412 | spin_unlock_irqrestore(&m->lock, flags); | |
413 | ||
414 | return 0; | |
415 | } | |
416 | ||
417 | /*----------------------------------------------------------------- | |
418 | * The multipath daemon is responsible for resubmitting queued ios. | |
419 | *---------------------------------------------------------------*/ | |
420 | ||
421 | static void dispatch_queued_ios(struct multipath *m) | |
422 | { | |
423 | int r; | |
424 | unsigned long flags; | |
028867ac | 425 | struct dm_mpath_io *mpio; |
1da177e4 | 426 | union map_info *info; |
f40c67f0 KU |
427 | struct request *clone, *n; |
428 | LIST_HEAD(cl); | |
1da177e4 LT |
429 | |
430 | spin_lock_irqsave(&m->lock, flags); | |
f40c67f0 | 431 | list_splice_init(&m->queued_ios, &cl); |
1da177e4 LT |
432 | spin_unlock_irqrestore(&m->lock, flags); |
433 | ||
f40c67f0 KU |
434 | list_for_each_entry_safe(clone, n, &cl, queuelist) { |
435 | list_del_init(&clone->queuelist); | |
1da177e4 | 436 | |
f40c67f0 | 437 | info = dm_get_rq_mapinfo(clone); |
1da177e4 LT |
438 | mpio = info->ptr; |
439 | ||
f40c67f0 KU |
440 | r = map_io(m, clone, mpio, 1); |
441 | if (r < 0) { | |
442 | mempool_free(mpio, m->mpio_pool); | |
443 | dm_kill_unmapped_request(clone, r); | |
444 | } else if (r == DM_MAPIO_REMAPPED) | |
445 | dm_dispatch_request(clone); | |
446 | else if (r == DM_MAPIO_REQUEUE) { | |
447 | mempool_free(mpio, m->mpio_pool); | |
448 | dm_requeue_unmapped_request(clone); | |
449 | } | |
1da177e4 LT |
450 | } |
451 | } | |
452 | ||
c4028958 | 453 | static void process_queued_ios(struct work_struct *work) |
1da177e4 | 454 | { |
c4028958 DH |
455 | struct multipath *m = |
456 | container_of(work, struct multipath, process_queued_ios); | |
fb612642 | 457 | struct pgpath *pgpath = NULL; |
e54f77dd | 458 | unsigned must_queue = 1; |
1da177e4 LT |
459 | unsigned long flags; |
460 | ||
461 | spin_lock_irqsave(&m->lock, flags); | |
462 | ||
c3cd4f6b AK |
463 | if (!m->queue_size) |
464 | goto out; | |
465 | ||
1da177e4 | 466 | if (!m->current_pgpath) |
02ab823f | 467 | __choose_pgpath(m, 0); |
1da177e4 LT |
468 | |
469 | pgpath = m->current_pgpath; | |
470 | ||
c3cd4f6b AK |
471 | if ((pgpath && !m->queue_io) || |
472 | (!pgpath && !m->queue_if_no_path)) | |
473 | must_queue = 0; | |
1da177e4 | 474 | |
fb612642 KU |
475 | if (m->pg_init_required && !m->pg_init_in_progress && pgpath) |
476 | __pg_init_all_paths(m); | |
477 | ||
c3cd4f6b | 478 | out: |
1da177e4 | 479 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 LT |
480 | if (!must_queue) |
481 | dispatch_queued_ios(m); | |
482 | } | |
483 | ||
484 | /* | |
485 | * An event is triggered whenever a path is taken out of use. | |
486 | * Includes path failure and PG bypass. | |
487 | */ | |
c4028958 | 488 | static void trigger_event(struct work_struct *work) |
1da177e4 | 489 | { |
c4028958 DH |
490 | struct multipath *m = |
491 | container_of(work, struct multipath, trigger_event); | |
1da177e4 LT |
492 | |
493 | dm_table_event(m->ti->table); | |
494 | } | |
495 | ||
496 | /*----------------------------------------------------------------- | |
497 | * Constructor/argument parsing: | |
498 | * <#multipath feature args> [<arg>]* | |
499 | * <#hw_handler args> [hw_handler [<arg>]*] | |
500 | * <#priority groups> | |
501 | * <initial priority group> | |
502 | * [<selector> <#selector args> [<arg>]* | |
503 | * <#paths> <#per-path selector args> | |
504 | * [<path> [<arg>]* ]+ ]+ | |
505 | *---------------------------------------------------------------*/ | |
506 | struct param { | |
507 | unsigned min; | |
508 | unsigned max; | |
509 | char *error; | |
510 | }; | |
511 | ||
1da177e4 LT |
512 | static int read_param(struct param *param, char *str, unsigned *v, char **error) |
513 | { | |
514 | if (!str || | |
515 | (sscanf(str, "%u", v) != 1) || | |
516 | (*v < param->min) || | |
517 | (*v > param->max)) { | |
518 | *error = param->error; | |
519 | return -EINVAL; | |
520 | } | |
521 | ||
522 | return 0; | |
523 | } | |
524 | ||
525 | struct arg_set { | |
526 | unsigned argc; | |
527 | char **argv; | |
528 | }; | |
529 | ||
530 | static char *shift(struct arg_set *as) | |
531 | { | |
532 | char *r; | |
533 | ||
534 | if (as->argc) { | |
535 | as->argc--; | |
536 | r = *as->argv; | |
537 | as->argv++; | |
538 | return r; | |
539 | } | |
540 | ||
541 | return NULL; | |
542 | } | |
543 | ||
544 | static void consume(struct arg_set *as, unsigned n) | |
545 | { | |
546 | BUG_ON (as->argc < n); | |
547 | as->argc -= n; | |
548 | as->argv += n; | |
549 | } | |
550 | ||
551 | static int parse_path_selector(struct arg_set *as, struct priority_group *pg, | |
552 | struct dm_target *ti) | |
553 | { | |
554 | int r; | |
555 | struct path_selector_type *pst; | |
556 | unsigned ps_argc; | |
557 | ||
558 | static struct param _params[] = { | |
72d94861 | 559 | {0, 1024, "invalid number of path selector args"}, |
1da177e4 LT |
560 | }; |
561 | ||
562 | pst = dm_get_path_selector(shift(as)); | |
563 | if (!pst) { | |
72d94861 | 564 | ti->error = "unknown path selector type"; |
1da177e4 LT |
565 | return -EINVAL; |
566 | } | |
567 | ||
568 | r = read_param(_params, shift(as), &ps_argc, &ti->error); | |
371b2e34 MP |
569 | if (r) { |
570 | dm_put_path_selector(pst); | |
1da177e4 | 571 | return -EINVAL; |
371b2e34 | 572 | } |
1da177e4 | 573 | |
0e0497c0 MP |
574 | if (ps_argc > as->argc) { |
575 | dm_put_path_selector(pst); | |
576 | ti->error = "not enough arguments for path selector"; | |
577 | return -EINVAL; | |
578 | } | |
579 | ||
1da177e4 LT |
580 | r = pst->create(&pg->ps, ps_argc, as->argv); |
581 | if (r) { | |
582 | dm_put_path_selector(pst); | |
72d94861 | 583 | ti->error = "path selector constructor failed"; |
1da177e4 LT |
584 | return r; |
585 | } | |
586 | ||
587 | pg->ps.type = pst; | |
588 | consume(as, ps_argc); | |
589 | ||
590 | return 0; | |
591 | } | |
592 | ||
593 | static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps, | |
594 | struct dm_target *ti) | |
595 | { | |
596 | int r; | |
597 | struct pgpath *p; | |
ae11b1b3 | 598 | struct multipath *m = ti->private; |
1da177e4 LT |
599 | |
600 | /* we need at least a path arg */ | |
601 | if (as->argc < 1) { | |
72d94861 | 602 | ti->error = "no device given"; |
01460f35 | 603 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
604 | } |
605 | ||
606 | p = alloc_pgpath(); | |
607 | if (!p) | |
01460f35 | 608 | return ERR_PTR(-ENOMEM); |
1da177e4 | 609 | |
8215d6ec NK |
610 | r = dm_get_device(ti, shift(as), dm_table_get_mode(ti->table), |
611 | &p->path.dev); | |
1da177e4 | 612 | if (r) { |
72d94861 | 613 | ti->error = "error getting device"; |
1da177e4 LT |
614 | goto bad; |
615 | } | |
616 | ||
ae11b1b3 | 617 | if (m->hw_handler_name) { |
a0cf7ea9 HR |
618 | struct request_queue *q = bdev_get_queue(p->path.dev->bdev); |
619 | ||
620 | r = scsi_dh_attach(q, m->hw_handler_name); | |
621 | if (r == -EBUSY) { | |
622 | /* | |
623 | * Already attached to different hw_handler, | |
624 | * try to reattach with correct one. | |
625 | */ | |
626 | scsi_dh_detach(q); | |
627 | r = scsi_dh_attach(q, m->hw_handler_name); | |
628 | } | |
629 | ||
ae11b1b3 | 630 | if (r < 0) { |
a0cf7ea9 | 631 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
632 | dm_put_device(ti, p->path.dev); |
633 | goto bad; | |
634 | } | |
2bfd2e13 CS |
635 | |
636 | if (m->hw_handler_params) { | |
637 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
638 | if (r < 0) { | |
639 | ti->error = "unable to set hardware " | |
640 | "handler parameters"; | |
641 | scsi_dh_detach(q); | |
642 | dm_put_device(ti, p->path.dev); | |
643 | goto bad; | |
644 | } | |
645 | } | |
ae11b1b3 HR |
646 | } |
647 | ||
1da177e4 LT |
648 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
649 | if (r) { | |
650 | dm_put_device(ti, p->path.dev); | |
651 | goto bad; | |
652 | } | |
653 | ||
654 | return p; | |
655 | ||
656 | bad: | |
657 | free_pgpath(p); | |
01460f35 | 658 | return ERR_PTR(r); |
1da177e4 LT |
659 | } |
660 | ||
661 | static struct priority_group *parse_priority_group(struct arg_set *as, | |
28f16c20 | 662 | struct multipath *m) |
1da177e4 LT |
663 | { |
664 | static struct param _params[] = { | |
72d94861 AK |
665 | {1, 1024, "invalid number of paths"}, |
666 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
667 | }; |
668 | ||
669 | int r; | |
670 | unsigned i, nr_selector_args, nr_params; | |
671 | struct priority_group *pg; | |
28f16c20 | 672 | struct dm_target *ti = m->ti; |
1da177e4 LT |
673 | |
674 | if (as->argc < 2) { | |
675 | as->argc = 0; | |
01460f35 BM |
676 | ti->error = "not enough priority group arguments"; |
677 | return ERR_PTR(-EINVAL); | |
1da177e4 LT |
678 | } |
679 | ||
680 | pg = alloc_priority_group(); | |
681 | if (!pg) { | |
72d94861 | 682 | ti->error = "couldn't allocate priority group"; |
01460f35 | 683 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
684 | } |
685 | pg->m = m; | |
686 | ||
687 | r = parse_path_selector(as, pg, ti); | |
688 | if (r) | |
689 | goto bad; | |
690 | ||
691 | /* | |
692 | * read the paths | |
693 | */ | |
694 | r = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error); | |
695 | if (r) | |
696 | goto bad; | |
697 | ||
698 | r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error); | |
699 | if (r) | |
700 | goto bad; | |
701 | ||
702 | nr_params = 1 + nr_selector_args; | |
703 | for (i = 0; i < pg->nr_pgpaths; i++) { | |
704 | struct pgpath *pgpath; | |
705 | struct arg_set path_args; | |
706 | ||
148acff6 MP |
707 | if (as->argc < nr_params) { |
708 | ti->error = "not enough path parameters"; | |
1da177e4 | 709 | goto bad; |
148acff6 | 710 | } |
1da177e4 LT |
711 | |
712 | path_args.argc = nr_params; | |
713 | path_args.argv = as->argv; | |
714 | ||
715 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
716 | if (IS_ERR(pgpath)) { |
717 | r = PTR_ERR(pgpath); | |
1da177e4 | 718 | goto bad; |
01460f35 | 719 | } |
1da177e4 LT |
720 | |
721 | pgpath->pg = pg; | |
722 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
723 | consume(as, nr_params); | |
724 | } | |
725 | ||
726 | return pg; | |
727 | ||
728 | bad: | |
729 | free_priority_group(pg, ti); | |
01460f35 | 730 | return ERR_PTR(r); |
1da177e4 LT |
731 | } |
732 | ||
28f16c20 | 733 | static int parse_hw_handler(struct arg_set *as, struct multipath *m) |
1da177e4 | 734 | { |
1da177e4 | 735 | unsigned hw_argc; |
2bfd2e13 | 736 | int ret; |
28f16c20 | 737 | struct dm_target *ti = m->ti; |
1da177e4 LT |
738 | |
739 | static struct param _params[] = { | |
72d94861 | 740 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
741 | }; |
742 | ||
cfae5c9b | 743 | if (read_param(_params, shift(as), &hw_argc, &ti->error)) |
1da177e4 LT |
744 | return -EINVAL; |
745 | ||
746 | if (!hw_argc) | |
747 | return 0; | |
748 | ||
e094f4f1 MP |
749 | if (hw_argc > as->argc) { |
750 | ti->error = "not enough arguments for hardware handler"; | |
751 | return -EINVAL; | |
752 | } | |
753 | ||
cfae5c9b CS |
754 | m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL); |
755 | request_module("scsi_dh_%s", m->hw_handler_name); | |
756 | if (scsi_dh_handler_exist(m->hw_handler_name) == 0) { | |
72d94861 | 757 | ti->error = "unknown hardware handler type"; |
2bfd2e13 CS |
758 | ret = -EINVAL; |
759 | goto fail; | |
1da177e4 | 760 | } |
14e98c5c | 761 | |
2bfd2e13 CS |
762 | if (hw_argc > 1) { |
763 | char *p; | |
764 | int i, j, len = 4; | |
765 | ||
766 | for (i = 0; i <= hw_argc - 2; i++) | |
767 | len += strlen(as->argv[i]) + 1; | |
768 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
769 | if (!p) { | |
770 | ti->error = "memory allocation failed"; | |
771 | ret = -ENOMEM; | |
772 | goto fail; | |
773 | } | |
774 | j = sprintf(p, "%d", hw_argc - 1); | |
775 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
776 | j = sprintf(p, "%s", as->argv[i]); | |
777 | } | |
1da177e4 LT |
778 | consume(as, hw_argc - 1); |
779 | ||
780 | return 0; | |
2bfd2e13 CS |
781 | fail: |
782 | kfree(m->hw_handler_name); | |
783 | m->hw_handler_name = NULL; | |
784 | return ret; | |
1da177e4 LT |
785 | } |
786 | ||
28f16c20 | 787 | static int parse_features(struct arg_set *as, struct multipath *m) |
1da177e4 LT |
788 | { |
789 | int r; | |
790 | unsigned argc; | |
28f16c20 | 791 | struct dm_target *ti = m->ti; |
c9e45581 | 792 | const char *param_name; |
1da177e4 LT |
793 | |
794 | static struct param _params[] = { | |
c9e45581 DW |
795 | {0, 3, "invalid number of feature args"}, |
796 | {1, 50, "pg_init_retries must be between 1 and 50"}, | |
1da177e4 LT |
797 | }; |
798 | ||
799 | r = read_param(_params, shift(as), &argc, &ti->error); | |
800 | if (r) | |
801 | return -EINVAL; | |
802 | ||
803 | if (!argc) | |
804 | return 0; | |
805 | ||
c9e45581 DW |
806 | do { |
807 | param_name = shift(as); | |
808 | argc--; | |
809 | ||
810 | if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) { | |
811 | r = queue_if_no_path(m, 1, 0); | |
812 | continue; | |
813 | } | |
814 | ||
815 | if (!strnicmp(param_name, MESG_STR("pg_init_retries")) && | |
816 | (argc >= 1)) { | |
817 | r = read_param(_params + 1, shift(as), | |
818 | &m->pg_init_retries, &ti->error); | |
819 | argc--; | |
820 | continue; | |
821 | } | |
822 | ||
1da177e4 | 823 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
824 | r = -EINVAL; |
825 | } while (argc && !r); | |
826 | ||
827 | return r; | |
1da177e4 LT |
828 | } |
829 | ||
830 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
831 | char **argv) | |
832 | { | |
833 | /* target parameters */ | |
834 | static struct param _params[] = { | |
72d94861 AK |
835 | {1, 1024, "invalid number of priority groups"}, |
836 | {1, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
837 | }; |
838 | ||
839 | int r; | |
840 | struct multipath *m; | |
841 | struct arg_set as; | |
842 | unsigned pg_count = 0; | |
843 | unsigned next_pg_num; | |
844 | ||
845 | as.argc = argc; | |
846 | as.argv = argv; | |
847 | ||
28f16c20 | 848 | m = alloc_multipath(ti); |
1da177e4 | 849 | if (!m) { |
72d94861 | 850 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
851 | return -EINVAL; |
852 | } | |
853 | ||
28f16c20 | 854 | r = parse_features(&as, m); |
1da177e4 LT |
855 | if (r) |
856 | goto bad; | |
857 | ||
28f16c20 | 858 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
859 | if (r) |
860 | goto bad; | |
861 | ||
862 | r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error); | |
863 | if (r) | |
864 | goto bad; | |
865 | ||
866 | r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error); | |
867 | if (r) | |
868 | goto bad; | |
869 | ||
870 | /* parse the priority groups */ | |
871 | while (as.argc) { | |
872 | struct priority_group *pg; | |
873 | ||
28f16c20 | 874 | pg = parse_priority_group(&as, m); |
01460f35 BM |
875 | if (IS_ERR(pg)) { |
876 | r = PTR_ERR(pg); | |
1da177e4 LT |
877 | goto bad; |
878 | } | |
879 | ||
880 | m->nr_valid_paths += pg->nr_pgpaths; | |
881 | list_add_tail(&pg->list, &m->priority_groups); | |
882 | pg_count++; | |
883 | pg->pg_num = pg_count; | |
884 | if (!--next_pg_num) | |
885 | m->next_pg = pg; | |
886 | } | |
887 | ||
888 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 889 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
890 | r = -EINVAL; |
891 | goto bad; | |
892 | } | |
893 | ||
8627921f MP |
894 | ti->num_flush_requests = 1; |
895 | ||
1da177e4 LT |
896 | return 0; |
897 | ||
898 | bad: | |
899 | free_multipath(m); | |
900 | return r; | |
901 | } | |
902 | ||
2bded7bd KU |
903 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
904 | { | |
905 | DECLARE_WAITQUEUE(wait, current); | |
906 | unsigned long flags; | |
907 | ||
908 | add_wait_queue(&m->pg_init_wait, &wait); | |
909 | ||
910 | while (1) { | |
911 | set_current_state(TASK_UNINTERRUPTIBLE); | |
912 | ||
913 | spin_lock_irqsave(&m->lock, flags); | |
914 | if (!m->pg_init_in_progress) { | |
915 | spin_unlock_irqrestore(&m->lock, flags); | |
916 | break; | |
917 | } | |
918 | spin_unlock_irqrestore(&m->lock, flags); | |
919 | ||
920 | io_schedule(); | |
921 | } | |
922 | set_current_state(TASK_RUNNING); | |
923 | ||
924 | remove_wait_queue(&m->pg_init_wait, &wait); | |
925 | } | |
926 | ||
927 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 928 | { |
bab7cfc7 | 929 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 930 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 931 | flush_workqueue(kmultipathd); |
53b351f9 | 932 | flush_scheduled_work(); |
6df400ab KU |
933 | } |
934 | ||
935 | static void multipath_dtr(struct dm_target *ti) | |
936 | { | |
937 | struct multipath *m = ti->private; | |
938 | ||
2bded7bd | 939 | flush_multipath_work(m); |
1da177e4 LT |
940 | free_multipath(m); |
941 | } | |
942 | ||
943 | /* | |
f40c67f0 | 944 | * Map cloned requests |
1da177e4 | 945 | */ |
f40c67f0 | 946 | static int multipath_map(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
947 | union map_info *map_context) |
948 | { | |
949 | int r; | |
028867ac | 950 | struct dm_mpath_io *mpio; |
1da177e4 LT |
951 | struct multipath *m = (struct multipath *) ti->private; |
952 | ||
f40c67f0 KU |
953 | mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); |
954 | if (!mpio) | |
955 | /* ENOMEM, requeue */ | |
956 | return DM_MAPIO_REQUEUE; | |
957 | memset(mpio, 0, sizeof(*mpio)); | |
1da177e4 LT |
958 | |
959 | map_context->ptr = mpio; | |
f40c67f0 KU |
960 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; |
961 | r = map_io(m, clone, mpio, 0); | |
45e15720 | 962 | if (r < 0 || r == DM_MAPIO_REQUEUE) |
1da177e4 LT |
963 | mempool_free(mpio, m->mpio_pool); |
964 | ||
965 | return r; | |
966 | } | |
967 | ||
968 | /* | |
969 | * Take a path out of use. | |
970 | */ | |
971 | static int fail_path(struct pgpath *pgpath) | |
972 | { | |
973 | unsigned long flags; | |
974 | struct multipath *m = pgpath->pg->m; | |
975 | ||
976 | spin_lock_irqsave(&m->lock, flags); | |
977 | ||
6680073d | 978 | if (!pgpath->is_active) |
1da177e4 LT |
979 | goto out; |
980 | ||
72d94861 | 981 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
982 | |
983 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
6680073d | 984 | pgpath->is_active = 0; |
1da177e4 LT |
985 | pgpath->fail_count++; |
986 | ||
987 | m->nr_valid_paths--; | |
988 | ||
989 | if (pgpath == m->current_pgpath) | |
990 | m->current_pgpath = NULL; | |
991 | ||
b15546f9 MA |
992 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
993 | pgpath->path.dev->name, m->nr_valid_paths); | |
994 | ||
fe9cf30e | 995 | schedule_work(&m->trigger_event); |
224cb3e9 | 996 | queue_work(kmultipathd, &pgpath->deactivate_path); |
1da177e4 LT |
997 | |
998 | out: | |
999 | spin_unlock_irqrestore(&m->lock, flags); | |
1000 | ||
1001 | return 0; | |
1002 | } | |
1003 | ||
1004 | /* | |
1005 | * Reinstate a previously-failed path | |
1006 | */ | |
1007 | static int reinstate_path(struct pgpath *pgpath) | |
1008 | { | |
1009 | int r = 0; | |
1010 | unsigned long flags; | |
1011 | struct multipath *m = pgpath->pg->m; | |
1012 | ||
1013 | spin_lock_irqsave(&m->lock, flags); | |
1014 | ||
6680073d | 1015 | if (pgpath->is_active) |
1da177e4 LT |
1016 | goto out; |
1017 | ||
def052d2 | 1018 | if (!pgpath->pg->ps.type->reinstate_path) { |
1da177e4 LT |
1019 | DMWARN("Reinstate path not supported by path selector %s", |
1020 | pgpath->pg->ps.type->name); | |
1021 | r = -EINVAL; | |
1022 | goto out; | |
1023 | } | |
1024 | ||
1025 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1026 | if (r) | |
1027 | goto out; | |
1028 | ||
6680073d | 1029 | pgpath->is_active = 1; |
1da177e4 | 1030 | |
e54f77dd CS |
1031 | if (!m->nr_valid_paths++ && m->queue_size) { |
1032 | m->current_pgpath = NULL; | |
c557308e | 1033 | queue_work(kmultipathd, &m->process_queued_ios); |
e54f77dd CS |
1034 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
1035 | if (queue_work(kmpath_handlerd, &pgpath->activate_path)) | |
1036 | m->pg_init_in_progress++; | |
1037 | } | |
1da177e4 | 1038 | |
b15546f9 MA |
1039 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
1040 | pgpath->path.dev->name, m->nr_valid_paths); | |
1041 | ||
fe9cf30e | 1042 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1043 | |
1044 | out: | |
1045 | spin_unlock_irqrestore(&m->lock, flags); | |
1046 | ||
1047 | return r; | |
1048 | } | |
1049 | ||
1050 | /* | |
1051 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1052 | */ | |
1053 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1054 | action_fn action) | |
1055 | { | |
1056 | int r = 0; | |
1057 | struct pgpath *pgpath; | |
1058 | struct priority_group *pg; | |
1059 | ||
1060 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1061 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1062 | if (pgpath->path.dev == dev) | |
1063 | r = action(pgpath); | |
1064 | } | |
1065 | } | |
1066 | ||
1067 | return r; | |
1068 | } | |
1069 | ||
1070 | /* | |
1071 | * Temporarily try to avoid having to use the specified PG | |
1072 | */ | |
1073 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
1074 | int bypassed) | |
1075 | { | |
1076 | unsigned long flags; | |
1077 | ||
1078 | spin_lock_irqsave(&m->lock, flags); | |
1079 | ||
1080 | pg->bypassed = bypassed; | |
1081 | m->current_pgpath = NULL; | |
1082 | m->current_pg = NULL; | |
1083 | ||
1084 | spin_unlock_irqrestore(&m->lock, flags); | |
1085 | ||
fe9cf30e | 1086 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1087 | } |
1088 | ||
1089 | /* | |
1090 | * Switch to using the specified PG from the next I/O that gets mapped | |
1091 | */ | |
1092 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1093 | { | |
1094 | struct priority_group *pg; | |
1095 | unsigned pgnum; | |
1096 | unsigned long flags; | |
1097 | ||
1098 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
1099 | (pgnum > m->nr_priority_groups)) { | |
1100 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1101 | return -EINVAL; | |
1102 | } | |
1103 | ||
1104 | spin_lock_irqsave(&m->lock, flags); | |
1105 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1106 | pg->bypassed = 0; | |
1107 | if (--pgnum) | |
1108 | continue; | |
1109 | ||
1110 | m->current_pgpath = NULL; | |
1111 | m->current_pg = NULL; | |
1112 | m->next_pg = pg; | |
1113 | } | |
1114 | spin_unlock_irqrestore(&m->lock, flags); | |
1115 | ||
fe9cf30e | 1116 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1117 | return 0; |
1118 | } | |
1119 | ||
1120 | /* | |
1121 | * Set/clear bypassed status of a PG. | |
1122 | * PGs are numbered upwards from 1 in the order they were declared. | |
1123 | */ | |
1124 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
1125 | { | |
1126 | struct priority_group *pg; | |
1127 | unsigned pgnum; | |
1128 | ||
1129 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
1130 | (pgnum > m->nr_priority_groups)) { | |
1131 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1132 | return -EINVAL; | |
1133 | } | |
1134 | ||
1135 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1136 | if (!--pgnum) | |
1137 | break; | |
1138 | } | |
1139 | ||
1140 | bypass_pg(m, pg, bypassed); | |
1141 | return 0; | |
1142 | } | |
1143 | ||
c9e45581 DW |
1144 | /* |
1145 | * Should we retry pg_init immediately? | |
1146 | */ | |
1147 | static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) | |
1148 | { | |
1149 | unsigned long flags; | |
1150 | int limit_reached = 0; | |
1151 | ||
1152 | spin_lock_irqsave(&m->lock, flags); | |
1153 | ||
1154 | if (m->pg_init_count <= m->pg_init_retries) | |
1155 | m->pg_init_required = 1; | |
1156 | else | |
1157 | limit_reached = 1; | |
1158 | ||
1159 | spin_unlock_irqrestore(&m->lock, flags); | |
1160 | ||
1161 | return limit_reached; | |
1162 | } | |
1163 | ||
3ae31f6a | 1164 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1165 | { |
83c0d5d5 | 1166 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1167 | struct priority_group *pg = pgpath->pg; |
1168 | struct multipath *m = pg->m; | |
1169 | unsigned long flags; | |
1170 | ||
1171 | /* device or driver problems */ | |
1172 | switch (errors) { | |
1173 | case SCSI_DH_OK: | |
1174 | break; | |
1175 | case SCSI_DH_NOSYS: | |
1176 | if (!m->hw_handler_name) { | |
1177 | errors = 0; | |
1178 | break; | |
1179 | } | |
f7b934c8 MB |
1180 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1181 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1182 | /* |
1183 | * Fail path for now, so we do not ping pong | |
1184 | */ | |
1185 | fail_path(pgpath); | |
1186 | break; | |
1187 | case SCSI_DH_DEV_TEMP_BUSY: | |
1188 | /* | |
1189 | * Probably doing something like FW upgrade on the | |
1190 | * controller so try the other pg. | |
1191 | */ | |
1192 | bypass_pg(m, pg, 1); | |
1193 | break; | |
1194 | /* TODO: For SCSI_DH_RETRY we should wait a couple seconds */ | |
1195 | case SCSI_DH_RETRY: | |
1196 | case SCSI_DH_IMM_RETRY: | |
1197 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1198 | if (pg_init_limit_reached(m, pgpath)) | |
1199 | fail_path(pgpath); | |
1200 | errors = 0; | |
1201 | break; | |
1202 | default: | |
1203 | /* | |
1204 | * We probably do not want to fail the path for a device | |
1205 | * error, but this is what the old dm did. In future | |
1206 | * patches we can do more advanced handling. | |
1207 | */ | |
1208 | fail_path(pgpath); | |
1209 | } | |
1210 | ||
1211 | spin_lock_irqsave(&m->lock, flags); | |
1212 | if (errors) { | |
e54f77dd CS |
1213 | if (pgpath == m->current_pgpath) { |
1214 | DMERR("Could not failover device. Error %d.", errors); | |
1215 | m->current_pgpath = NULL; | |
1216 | m->current_pg = NULL; | |
1217 | } | |
d0259bf0 | 1218 | } else if (!m->pg_init_required) |
cfae5c9b | 1219 | pg->bypassed = 0; |
cfae5c9b | 1220 | |
d0259bf0 KU |
1221 | if (--m->pg_init_in_progress) |
1222 | /* Activations of other paths are still on going */ | |
1223 | goto out; | |
1224 | ||
1225 | if (!m->pg_init_required) | |
1226 | m->queue_io = 0; | |
1227 | ||
1228 | queue_work(kmultipathd, &m->process_queued_ios); | |
1229 | ||
2bded7bd KU |
1230 | /* |
1231 | * Wake up any thread waiting to suspend. | |
1232 | */ | |
1233 | wake_up(&m->pg_init_wait); | |
1234 | ||
d0259bf0 | 1235 | out: |
cfae5c9b CS |
1236 | spin_unlock_irqrestore(&m->lock, flags); |
1237 | } | |
1238 | ||
bab7cfc7 CS |
1239 | static void activate_path(struct work_struct *work) |
1240 | { | |
e54f77dd CS |
1241 | struct pgpath *pgpath = |
1242 | container_of(work, struct pgpath, activate_path); | |
bab7cfc7 | 1243 | |
3ae31f6a | 1244 | scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev), |
83c0d5d5 | 1245 | pg_init_done, pgpath); |
bab7cfc7 CS |
1246 | } |
1247 | ||
1da177e4 LT |
1248 | /* |
1249 | * end_io handling | |
1250 | */ | |
f40c67f0 | 1251 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1252 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1253 | { |
f40c67f0 KU |
1254 | /* |
1255 | * We don't queue any clone request inside the multipath target | |
1256 | * during end I/O handling, since those clone requests don't have | |
1257 | * bio clones. If we queue them inside the multipath target, | |
1258 | * we need to make bio clones, that requires memory allocation. | |
1259 | * (See drivers/md/dm.c:end_clone_bio() about why the clone requests | |
1260 | * don't have bio clones.) | |
1261 | * Instead of queueing the clone request here, we queue the original | |
1262 | * request into dm core, which will remake a clone request and | |
1263 | * clone bios for it and resubmit it later. | |
1264 | */ | |
1265 | int r = DM_ENDIO_REQUEUE; | |
640eb3b0 | 1266 | unsigned long flags; |
1da177e4 | 1267 | |
f40c67f0 | 1268 | if (!error && !clone->errors) |
1da177e4 LT |
1269 | return 0; /* I/O complete */ |
1270 | ||
f6a80ea8 AK |
1271 | if (error == -EOPNOTSUPP) |
1272 | return error; | |
1273 | ||
cfae5c9b CS |
1274 | if (mpio->pgpath) |
1275 | fail_path(mpio->pgpath); | |
1da177e4 | 1276 | |
640eb3b0 | 1277 | spin_lock_irqsave(&m->lock, flags); |
f40c67f0 KU |
1278 | if (!m->nr_valid_paths && !m->queue_if_no_path && !__must_push_back(m)) |
1279 | r = -EIO; | |
640eb3b0 | 1280 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 | 1281 | |
f40c67f0 | 1282 | return r; |
1da177e4 LT |
1283 | } |
1284 | ||
f40c67f0 | 1285 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1286 | int error, union map_info *map_context) |
1287 | { | |
028867ac AK |
1288 | struct multipath *m = ti->private; |
1289 | struct dm_mpath_io *mpio = map_context->ptr; | |
1da177e4 LT |
1290 | struct pgpath *pgpath = mpio->pgpath; |
1291 | struct path_selector *ps; | |
1292 | int r; | |
1293 | ||
f40c67f0 | 1294 | r = do_end_io(m, clone, error, mpio); |
1da177e4 LT |
1295 | if (pgpath) { |
1296 | ps = &pgpath->pg->ps; | |
1297 | if (ps->type->end_io) | |
02ab823f | 1298 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1299 | } |
f40c67f0 | 1300 | mempool_free(mpio, m->mpio_pool); |
1da177e4 LT |
1301 | |
1302 | return r; | |
1303 | } | |
1304 | ||
1305 | /* | |
1306 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1307 | * the last path fails we must error any remaining I/O. |
1308 | * Note that if the freeze_bdev fails while suspending, the | |
1309 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1310 | */ |
1311 | static void multipath_presuspend(struct dm_target *ti) | |
1312 | { | |
1313 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 | 1314 | |
485ef69e | 1315 | queue_if_no_path(m, 0, 1); |
1da177e4 LT |
1316 | } |
1317 | ||
6df400ab KU |
1318 | static void multipath_postsuspend(struct dm_target *ti) |
1319 | { | |
6380f26f MA |
1320 | struct multipath *m = ti->private; |
1321 | ||
1322 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1323 | flush_multipath_work(m); |
6380f26f | 1324 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1325 | } |
1326 | ||
436d4108 AK |
1327 | /* |
1328 | * Restore the queue_if_no_path setting. | |
1329 | */ | |
1da177e4 LT |
1330 | static void multipath_resume(struct dm_target *ti) |
1331 | { | |
1332 | struct multipath *m = (struct multipath *) ti->private; | |
1333 | unsigned long flags; | |
1334 | ||
1335 | spin_lock_irqsave(&m->lock, flags); | |
436d4108 | 1336 | m->queue_if_no_path = m->saved_queue_if_no_path; |
1da177e4 LT |
1337 | spin_unlock_irqrestore(&m->lock, flags); |
1338 | } | |
1339 | ||
1340 | /* | |
1341 | * Info output has the following format: | |
1342 | * num_multipath_feature_args [multipath_feature_args]* | |
1343 | * num_handler_status_args [handler_status_args]* | |
1344 | * num_groups init_group_number | |
1345 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1346 | * num_paths num_selector_args | |
1347 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1348 | * | |
1349 | * Table output has the following format (identical to the constructor string): | |
1350 | * num_feature_args [features_args]* | |
1351 | * num_handler_args hw_handler [hw_handler_args]* | |
1352 | * num_groups init_group_number | |
1353 | * [priority selector-name num_ps_args [ps_args]* | |
1354 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1355 | */ | |
1356 | static int multipath_status(struct dm_target *ti, status_type_t type, | |
1357 | char *result, unsigned int maxlen) | |
1358 | { | |
1359 | int sz = 0; | |
1360 | unsigned long flags; | |
1361 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 LT |
1362 | struct priority_group *pg; |
1363 | struct pgpath *p; | |
1364 | unsigned pg_num; | |
1365 | char state; | |
1366 | ||
1367 | spin_lock_irqsave(&m->lock, flags); | |
1368 | ||
1369 | /* Features */ | |
1370 | if (type == STATUSTYPE_INFO) | |
c9e45581 DW |
1371 | DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count); |
1372 | else { | |
1373 | DMEMIT("%u ", m->queue_if_no_path + | |
1374 | (m->pg_init_retries > 0) * 2); | |
1375 | if (m->queue_if_no_path) | |
1376 | DMEMIT("queue_if_no_path "); | |
1377 | if (m->pg_init_retries) | |
1378 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
1379 | } | |
1da177e4 | 1380 | |
cfae5c9b | 1381 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1382 | DMEMIT("0 "); |
1383 | else | |
cfae5c9b | 1384 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1385 | |
1386 | DMEMIT("%u ", m->nr_priority_groups); | |
1387 | ||
1388 | if (m->next_pg) | |
1389 | pg_num = m->next_pg->pg_num; | |
1390 | else if (m->current_pg) | |
1391 | pg_num = m->current_pg->pg_num; | |
1392 | else | |
1393 | pg_num = 1; | |
1394 | ||
1395 | DMEMIT("%u ", pg_num); | |
1396 | ||
1397 | switch (type) { | |
1398 | case STATUSTYPE_INFO: | |
1399 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1400 | if (pg->bypassed) | |
1401 | state = 'D'; /* Disabled */ | |
1402 | else if (pg == m->current_pg) | |
1403 | state = 'A'; /* Currently Active */ | |
1404 | else | |
1405 | state = 'E'; /* Enabled */ | |
1406 | ||
1407 | DMEMIT("%c ", state); | |
1408 | ||
1409 | if (pg->ps.type->status) | |
1410 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1411 | result + sz, | |
1412 | maxlen - sz); | |
1413 | else | |
1414 | DMEMIT("0 "); | |
1415 | ||
1416 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1417 | pg->ps.type->info_args); | |
1418 | ||
1419 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1420 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1421 | p->is_active ? "A" : "F", |
1da177e4 LT |
1422 | p->fail_count); |
1423 | if (pg->ps.type->status) | |
1424 | sz += pg->ps.type->status(&pg->ps, | |
1425 | &p->path, type, result + sz, | |
1426 | maxlen - sz); | |
1427 | } | |
1428 | } | |
1429 | break; | |
1430 | ||
1431 | case STATUSTYPE_TABLE: | |
1432 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1433 | DMEMIT("%s ", pg->ps.type->name); | |
1434 | ||
1435 | if (pg->ps.type->status) | |
1436 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1437 | result + sz, | |
1438 | maxlen - sz); | |
1439 | else | |
1440 | DMEMIT("0 "); | |
1441 | ||
1442 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1443 | pg->ps.type->table_args); | |
1444 | ||
1445 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1446 | DMEMIT("%s ", p->path.dev->name); | |
1447 | if (pg->ps.type->status) | |
1448 | sz += pg->ps.type->status(&pg->ps, | |
1449 | &p->path, type, result + sz, | |
1450 | maxlen - sz); | |
1451 | } | |
1452 | } | |
1453 | break; | |
1454 | } | |
1455 | ||
1456 | spin_unlock_irqrestore(&m->lock, flags); | |
1457 | ||
1458 | return 0; | |
1459 | } | |
1460 | ||
1461 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1462 | { | |
6380f26f | 1463 | int r = -EINVAL; |
1da177e4 LT |
1464 | struct dm_dev *dev; |
1465 | struct multipath *m = (struct multipath *) ti->private; | |
1466 | action_fn action; | |
1467 | ||
6380f26f MA |
1468 | mutex_lock(&m->work_mutex); |
1469 | ||
c2f3d24b KU |
1470 | if (dm_suspended(ti)) { |
1471 | r = -EBUSY; | |
1472 | goto out; | |
1473 | } | |
1474 | ||
1da177e4 | 1475 | if (argc == 1) { |
6380f26f MA |
1476 | if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) { |
1477 | r = queue_if_no_path(m, 1, 0); | |
1478 | goto out; | |
1479 | } else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) { | |
1480 | r = queue_if_no_path(m, 0, 0); | |
1481 | goto out; | |
1482 | } | |
1da177e4 LT |
1483 | } |
1484 | ||
6380f26f MA |
1485 | if (argc != 2) { |
1486 | DMWARN("Unrecognised multipath message received."); | |
1487 | goto out; | |
1488 | } | |
1da177e4 | 1489 | |
6380f26f MA |
1490 | if (!strnicmp(argv[0], MESG_STR("disable_group"))) { |
1491 | r = bypass_pg_num(m, argv[1], 1); | |
1492 | goto out; | |
1493 | } else if (!strnicmp(argv[0], MESG_STR("enable_group"))) { | |
1494 | r = bypass_pg_num(m, argv[1], 0); | |
1495 | goto out; | |
1496 | } else if (!strnicmp(argv[0], MESG_STR("switch_group"))) { | |
1497 | r = switch_pg_num(m, argv[1]); | |
1498 | goto out; | |
1499 | } else if (!strnicmp(argv[0], MESG_STR("reinstate_path"))) | |
1da177e4 LT |
1500 | action = reinstate_path; |
1501 | else if (!strnicmp(argv[0], MESG_STR("fail_path"))) | |
1502 | action = fail_path; | |
6380f26f MA |
1503 | else { |
1504 | DMWARN("Unrecognised multipath message received."); | |
1505 | goto out; | |
1506 | } | |
1da177e4 | 1507 | |
8215d6ec | 1508 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1509 | if (r) { |
72d94861 | 1510 | DMWARN("message: error getting device %s", |
1da177e4 | 1511 | argv[1]); |
6380f26f | 1512 | goto out; |
1da177e4 LT |
1513 | } |
1514 | ||
1515 | r = action_dev(m, dev, action); | |
1516 | ||
1517 | dm_put_device(ti, dev); | |
1518 | ||
6380f26f MA |
1519 | out: |
1520 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1521 | return r; |
1da177e4 LT |
1522 | } |
1523 | ||
647b3d00 | 1524 | static int multipath_ioctl(struct dm_target *ti, unsigned int cmd, |
9af4aa30 MB |
1525 | unsigned long arg) |
1526 | { | |
1527 | struct multipath *m = (struct multipath *) ti->private; | |
1528 | struct block_device *bdev = NULL; | |
633a08b8 | 1529 | fmode_t mode = 0; |
9af4aa30 MB |
1530 | unsigned long flags; |
1531 | int r = 0; | |
1532 | ||
1533 | spin_lock_irqsave(&m->lock, flags); | |
1534 | ||
1535 | if (!m->current_pgpath) | |
02ab823f | 1536 | __choose_pgpath(m, 0); |
9af4aa30 | 1537 | |
e90dae1f | 1538 | if (m->current_pgpath) { |
9af4aa30 | 1539 | bdev = m->current_pgpath->path.dev->bdev; |
633a08b8 | 1540 | mode = m->current_pgpath->path.dev->mode; |
e90dae1f | 1541 | } |
9af4aa30 MB |
1542 | |
1543 | if (m->queue_io) | |
1544 | r = -EAGAIN; | |
1545 | else if (!bdev) | |
1546 | r = -EIO; | |
1547 | ||
1548 | spin_unlock_irqrestore(&m->lock, flags); | |
1549 | ||
633a08b8 | 1550 | return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg); |
9af4aa30 MB |
1551 | } |
1552 | ||
af4874e0 MS |
1553 | static int multipath_iterate_devices(struct dm_target *ti, |
1554 | iterate_devices_callout_fn fn, void *data) | |
1555 | { | |
1556 | struct multipath *m = ti->private; | |
1557 | struct priority_group *pg; | |
1558 | struct pgpath *p; | |
1559 | int ret = 0; | |
1560 | ||
1561 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1562 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1563 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1564 | if (ret) |
1565 | goto out; | |
1566 | } | |
1567 | } | |
1568 | ||
1569 | out: | |
1570 | return ret; | |
1571 | } | |
1572 | ||
f40c67f0 KU |
1573 | static int __pgpath_busy(struct pgpath *pgpath) |
1574 | { | |
1575 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1576 | ||
1577 | return dm_underlying_device_busy(q); | |
1578 | } | |
1579 | ||
1580 | /* | |
1581 | * We return "busy", only when we can map I/Os but underlying devices | |
1582 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1583 | * the underlying queue). | |
1584 | * In other words, if we want to kill I/Os or queue them inside us | |
1585 | * due to map unavailability, we don't return "busy". Otherwise, | |
1586 | * dm core won't give us the I/Os and we can't do what we want. | |
1587 | */ | |
1588 | static int multipath_busy(struct dm_target *ti) | |
1589 | { | |
1590 | int busy = 0, has_active = 0; | |
1591 | struct multipath *m = ti->private; | |
1592 | struct priority_group *pg; | |
1593 | struct pgpath *pgpath; | |
1594 | unsigned long flags; | |
1595 | ||
1596 | spin_lock_irqsave(&m->lock, flags); | |
1597 | ||
1598 | /* Guess which priority_group will be used at next mapping time */ | |
1599 | if (unlikely(!m->current_pgpath && m->next_pg)) | |
1600 | pg = m->next_pg; | |
1601 | else if (likely(m->current_pg)) | |
1602 | pg = m->current_pg; | |
1603 | else | |
1604 | /* | |
1605 | * We don't know which pg will be used at next mapping time. | |
1606 | * We don't call __choose_pgpath() here to avoid to trigger | |
1607 | * pg_init just by busy checking. | |
1608 | * So we don't know whether underlying devices we will be using | |
1609 | * at next mapping time are busy or not. Just try mapping. | |
1610 | */ | |
1611 | goto out; | |
1612 | ||
1613 | /* | |
1614 | * If there is one non-busy active path at least, the path selector | |
1615 | * will be able to select it. So we consider such a pg as not busy. | |
1616 | */ | |
1617 | busy = 1; | |
1618 | list_for_each_entry(pgpath, &pg->pgpaths, list) | |
1619 | if (pgpath->is_active) { | |
1620 | has_active = 1; | |
1621 | ||
1622 | if (!__pgpath_busy(pgpath)) { | |
1623 | busy = 0; | |
1624 | break; | |
1625 | } | |
1626 | } | |
1627 | ||
1628 | if (!has_active) | |
1629 | /* | |
1630 | * No active path in this pg, so this pg won't be used and | |
1631 | * the current_pg will be changed at next mapping time. | |
1632 | * We need to try mapping to determine it. | |
1633 | */ | |
1634 | busy = 0; | |
1635 | ||
1636 | out: | |
1637 | spin_unlock_irqrestore(&m->lock, flags); | |
1638 | ||
1639 | return busy; | |
1640 | } | |
1641 | ||
1da177e4 LT |
1642 | /*----------------------------------------------------------------- |
1643 | * Module setup | |
1644 | *---------------------------------------------------------------*/ | |
1645 | static struct target_type multipath_target = { | |
1646 | .name = "multipath", | |
6df400ab | 1647 | .version = {1, 1, 1}, |
1da177e4 LT |
1648 | .module = THIS_MODULE, |
1649 | .ctr = multipath_ctr, | |
1650 | .dtr = multipath_dtr, | |
f40c67f0 KU |
1651 | .map_rq = multipath_map, |
1652 | .rq_end_io = multipath_end_io, | |
1da177e4 | 1653 | .presuspend = multipath_presuspend, |
6df400ab | 1654 | .postsuspend = multipath_postsuspend, |
1da177e4 LT |
1655 | .resume = multipath_resume, |
1656 | .status = multipath_status, | |
1657 | .message = multipath_message, | |
9af4aa30 | 1658 | .ioctl = multipath_ioctl, |
af4874e0 | 1659 | .iterate_devices = multipath_iterate_devices, |
f40c67f0 | 1660 | .busy = multipath_busy, |
1da177e4 LT |
1661 | }; |
1662 | ||
1663 | static int __init dm_multipath_init(void) | |
1664 | { | |
1665 | int r; | |
1666 | ||
1667 | /* allocate a slab for the dm_ios */ | |
028867ac | 1668 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
1669 | if (!_mpio_cache) |
1670 | return -ENOMEM; | |
1671 | ||
1672 | r = dm_register_target(&multipath_target); | |
1673 | if (r < 0) { | |
0cd33124 | 1674 | DMERR("register failed %d", r); |
1da177e4 LT |
1675 | kmem_cache_destroy(_mpio_cache); |
1676 | return -EINVAL; | |
1677 | } | |
1678 | ||
c557308e AK |
1679 | kmultipathd = create_workqueue("kmpathd"); |
1680 | if (!kmultipathd) { | |
0cd33124 | 1681 | DMERR("failed to create workqueue kmpathd"); |
c557308e AK |
1682 | dm_unregister_target(&multipath_target); |
1683 | kmem_cache_destroy(_mpio_cache); | |
1684 | return -ENOMEM; | |
1685 | } | |
1686 | ||
bab7cfc7 CS |
1687 | /* |
1688 | * A separate workqueue is used to handle the device handlers | |
1689 | * to avoid overloading existing workqueue. Overloading the | |
1690 | * old workqueue would also create a bottleneck in the | |
1691 | * path of the storage hardware device activation. | |
1692 | */ | |
1693 | kmpath_handlerd = create_singlethread_workqueue("kmpath_handlerd"); | |
1694 | if (!kmpath_handlerd) { | |
1695 | DMERR("failed to create workqueue kmpath_handlerd"); | |
1696 | destroy_workqueue(kmultipathd); | |
1697 | dm_unregister_target(&multipath_target); | |
1698 | kmem_cache_destroy(_mpio_cache); | |
1699 | return -ENOMEM; | |
1700 | } | |
1701 | ||
72d94861 | 1702 | DMINFO("version %u.%u.%u loaded", |
1da177e4 LT |
1703 | multipath_target.version[0], multipath_target.version[1], |
1704 | multipath_target.version[2]); | |
1705 | ||
1706 | return r; | |
1707 | } | |
1708 | ||
1709 | static void __exit dm_multipath_exit(void) | |
1710 | { | |
bab7cfc7 | 1711 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
1712 | destroy_workqueue(kmultipathd); |
1713 | ||
10d3bd09 | 1714 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
1715 | kmem_cache_destroy(_mpio_cache); |
1716 | } | |
1717 | ||
1da177e4 LT |
1718 | module_init(dm_multipath_init); |
1719 | module_exit(dm_multipath_exit); | |
1720 | ||
1721 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1722 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1723 | MODULE_LICENSE("GPL"); |