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"; | |
6bbf79a1 | 709 | r = -EINVAL; |
1da177e4 | 710 | goto bad; |
148acff6 | 711 | } |
1da177e4 LT |
712 | |
713 | path_args.argc = nr_params; | |
714 | path_args.argv = as->argv; | |
715 | ||
716 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
717 | if (IS_ERR(pgpath)) { |
718 | r = PTR_ERR(pgpath); | |
1da177e4 | 719 | goto bad; |
01460f35 | 720 | } |
1da177e4 LT |
721 | |
722 | pgpath->pg = pg; | |
723 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
724 | consume(as, nr_params); | |
725 | } | |
726 | ||
727 | return pg; | |
728 | ||
729 | bad: | |
730 | free_priority_group(pg, ti); | |
01460f35 | 731 | return ERR_PTR(r); |
1da177e4 LT |
732 | } |
733 | ||
28f16c20 | 734 | static int parse_hw_handler(struct arg_set *as, struct multipath *m) |
1da177e4 | 735 | { |
1da177e4 | 736 | unsigned hw_argc; |
2bfd2e13 | 737 | int ret; |
28f16c20 | 738 | struct dm_target *ti = m->ti; |
1da177e4 LT |
739 | |
740 | static struct param _params[] = { | |
72d94861 | 741 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
742 | }; |
743 | ||
cfae5c9b | 744 | if (read_param(_params, shift(as), &hw_argc, &ti->error)) |
1da177e4 LT |
745 | return -EINVAL; |
746 | ||
747 | if (!hw_argc) | |
748 | return 0; | |
749 | ||
e094f4f1 MP |
750 | if (hw_argc > as->argc) { |
751 | ti->error = "not enough arguments for hardware handler"; | |
752 | return -EINVAL; | |
753 | } | |
754 | ||
cfae5c9b CS |
755 | m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL); |
756 | request_module("scsi_dh_%s", m->hw_handler_name); | |
757 | if (scsi_dh_handler_exist(m->hw_handler_name) == 0) { | |
72d94861 | 758 | ti->error = "unknown hardware handler type"; |
2bfd2e13 CS |
759 | ret = -EINVAL; |
760 | goto fail; | |
1da177e4 | 761 | } |
14e98c5c | 762 | |
2bfd2e13 CS |
763 | if (hw_argc > 1) { |
764 | char *p; | |
765 | int i, j, len = 4; | |
766 | ||
767 | for (i = 0; i <= hw_argc - 2; i++) | |
768 | len += strlen(as->argv[i]) + 1; | |
769 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
770 | if (!p) { | |
771 | ti->error = "memory allocation failed"; | |
772 | ret = -ENOMEM; | |
773 | goto fail; | |
774 | } | |
775 | j = sprintf(p, "%d", hw_argc - 1); | |
776 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
777 | j = sprintf(p, "%s", as->argv[i]); | |
778 | } | |
1da177e4 LT |
779 | consume(as, hw_argc - 1); |
780 | ||
781 | return 0; | |
2bfd2e13 CS |
782 | fail: |
783 | kfree(m->hw_handler_name); | |
784 | m->hw_handler_name = NULL; | |
785 | return ret; | |
1da177e4 LT |
786 | } |
787 | ||
28f16c20 | 788 | static int parse_features(struct arg_set *as, struct multipath *m) |
1da177e4 LT |
789 | { |
790 | int r; | |
791 | unsigned argc; | |
28f16c20 | 792 | struct dm_target *ti = m->ti; |
c9e45581 | 793 | const char *param_name; |
1da177e4 LT |
794 | |
795 | static struct param _params[] = { | |
c9e45581 DW |
796 | {0, 3, "invalid number of feature args"}, |
797 | {1, 50, "pg_init_retries must be between 1 and 50"}, | |
1da177e4 LT |
798 | }; |
799 | ||
800 | r = read_param(_params, shift(as), &argc, &ti->error); | |
801 | if (r) | |
802 | return -EINVAL; | |
803 | ||
804 | if (!argc) | |
805 | return 0; | |
806 | ||
c9e45581 DW |
807 | do { |
808 | param_name = shift(as); | |
809 | argc--; | |
810 | ||
811 | if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) { | |
812 | r = queue_if_no_path(m, 1, 0); | |
813 | continue; | |
814 | } | |
815 | ||
816 | if (!strnicmp(param_name, MESG_STR("pg_init_retries")) && | |
817 | (argc >= 1)) { | |
818 | r = read_param(_params + 1, shift(as), | |
819 | &m->pg_init_retries, &ti->error); | |
820 | argc--; | |
821 | continue; | |
822 | } | |
823 | ||
1da177e4 | 824 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
825 | r = -EINVAL; |
826 | } while (argc && !r); | |
827 | ||
828 | return r; | |
1da177e4 LT |
829 | } |
830 | ||
831 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
832 | char **argv) | |
833 | { | |
834 | /* target parameters */ | |
835 | static struct param _params[] = { | |
72d94861 AK |
836 | {1, 1024, "invalid number of priority groups"}, |
837 | {1, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
838 | }; |
839 | ||
840 | int r; | |
841 | struct multipath *m; | |
842 | struct arg_set as; | |
843 | unsigned pg_count = 0; | |
844 | unsigned next_pg_num; | |
845 | ||
846 | as.argc = argc; | |
847 | as.argv = argv; | |
848 | ||
28f16c20 | 849 | m = alloc_multipath(ti); |
1da177e4 | 850 | if (!m) { |
72d94861 | 851 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
852 | return -EINVAL; |
853 | } | |
854 | ||
28f16c20 | 855 | r = parse_features(&as, m); |
1da177e4 LT |
856 | if (r) |
857 | goto bad; | |
858 | ||
28f16c20 | 859 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
860 | if (r) |
861 | goto bad; | |
862 | ||
863 | r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error); | |
864 | if (r) | |
865 | goto bad; | |
866 | ||
867 | r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error); | |
868 | if (r) | |
869 | goto bad; | |
870 | ||
871 | /* parse the priority groups */ | |
872 | while (as.argc) { | |
873 | struct priority_group *pg; | |
874 | ||
28f16c20 | 875 | pg = parse_priority_group(&as, m); |
01460f35 BM |
876 | if (IS_ERR(pg)) { |
877 | r = PTR_ERR(pg); | |
1da177e4 LT |
878 | goto bad; |
879 | } | |
880 | ||
881 | m->nr_valid_paths += pg->nr_pgpaths; | |
882 | list_add_tail(&pg->list, &m->priority_groups); | |
883 | pg_count++; | |
884 | pg->pg_num = pg_count; | |
885 | if (!--next_pg_num) | |
886 | m->next_pg = pg; | |
887 | } | |
888 | ||
889 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 890 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
891 | r = -EINVAL; |
892 | goto bad; | |
893 | } | |
894 | ||
8627921f | 895 | ti->num_flush_requests = 1; |
959eb4e5 | 896 | ti->num_discard_requests = 1; |
8627921f | 897 | |
1da177e4 LT |
898 | return 0; |
899 | ||
900 | bad: | |
901 | free_multipath(m); | |
902 | return r; | |
903 | } | |
904 | ||
2bded7bd KU |
905 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
906 | { | |
907 | DECLARE_WAITQUEUE(wait, current); | |
908 | unsigned long flags; | |
909 | ||
910 | add_wait_queue(&m->pg_init_wait, &wait); | |
911 | ||
912 | while (1) { | |
913 | set_current_state(TASK_UNINTERRUPTIBLE); | |
914 | ||
915 | spin_lock_irqsave(&m->lock, flags); | |
916 | if (!m->pg_init_in_progress) { | |
917 | spin_unlock_irqrestore(&m->lock, flags); | |
918 | break; | |
919 | } | |
920 | spin_unlock_irqrestore(&m->lock, flags); | |
921 | ||
922 | io_schedule(); | |
923 | } | |
924 | set_current_state(TASK_RUNNING); | |
925 | ||
926 | remove_wait_queue(&m->pg_init_wait, &wait); | |
927 | } | |
928 | ||
929 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 930 | { |
bab7cfc7 | 931 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 932 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 933 | flush_workqueue(kmultipathd); |
53b351f9 | 934 | flush_scheduled_work(); |
6df400ab KU |
935 | } |
936 | ||
937 | static void multipath_dtr(struct dm_target *ti) | |
938 | { | |
939 | struct multipath *m = ti->private; | |
940 | ||
2bded7bd | 941 | flush_multipath_work(m); |
1da177e4 LT |
942 | free_multipath(m); |
943 | } | |
944 | ||
945 | /* | |
f40c67f0 | 946 | * Map cloned requests |
1da177e4 | 947 | */ |
f40c67f0 | 948 | static int multipath_map(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
949 | union map_info *map_context) |
950 | { | |
951 | int r; | |
028867ac | 952 | struct dm_mpath_io *mpio; |
1da177e4 LT |
953 | struct multipath *m = (struct multipath *) ti->private; |
954 | ||
f40c67f0 KU |
955 | mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); |
956 | if (!mpio) | |
957 | /* ENOMEM, requeue */ | |
958 | return DM_MAPIO_REQUEUE; | |
959 | memset(mpio, 0, sizeof(*mpio)); | |
1da177e4 LT |
960 | |
961 | map_context->ptr = mpio; | |
f40c67f0 KU |
962 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; |
963 | r = map_io(m, clone, mpio, 0); | |
45e15720 | 964 | if (r < 0 || r == DM_MAPIO_REQUEUE) |
1da177e4 LT |
965 | mempool_free(mpio, m->mpio_pool); |
966 | ||
967 | return r; | |
968 | } | |
969 | ||
970 | /* | |
971 | * Take a path out of use. | |
972 | */ | |
973 | static int fail_path(struct pgpath *pgpath) | |
974 | { | |
975 | unsigned long flags; | |
976 | struct multipath *m = pgpath->pg->m; | |
977 | ||
978 | spin_lock_irqsave(&m->lock, flags); | |
979 | ||
6680073d | 980 | if (!pgpath->is_active) |
1da177e4 LT |
981 | goto out; |
982 | ||
72d94861 | 983 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
984 | |
985 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
6680073d | 986 | pgpath->is_active = 0; |
1da177e4 LT |
987 | pgpath->fail_count++; |
988 | ||
989 | m->nr_valid_paths--; | |
990 | ||
991 | if (pgpath == m->current_pgpath) | |
992 | m->current_pgpath = NULL; | |
993 | ||
b15546f9 MA |
994 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
995 | pgpath->path.dev->name, m->nr_valid_paths); | |
996 | ||
fe9cf30e | 997 | schedule_work(&m->trigger_event); |
224cb3e9 | 998 | queue_work(kmultipathd, &pgpath->deactivate_path); |
1da177e4 LT |
999 | |
1000 | out: | |
1001 | spin_unlock_irqrestore(&m->lock, flags); | |
1002 | ||
1003 | return 0; | |
1004 | } | |
1005 | ||
1006 | /* | |
1007 | * Reinstate a previously-failed path | |
1008 | */ | |
1009 | static int reinstate_path(struct pgpath *pgpath) | |
1010 | { | |
1011 | int r = 0; | |
1012 | unsigned long flags; | |
1013 | struct multipath *m = pgpath->pg->m; | |
1014 | ||
1015 | spin_lock_irqsave(&m->lock, flags); | |
1016 | ||
6680073d | 1017 | if (pgpath->is_active) |
1da177e4 LT |
1018 | goto out; |
1019 | ||
def052d2 | 1020 | if (!pgpath->pg->ps.type->reinstate_path) { |
1da177e4 LT |
1021 | DMWARN("Reinstate path not supported by path selector %s", |
1022 | pgpath->pg->ps.type->name); | |
1023 | r = -EINVAL; | |
1024 | goto out; | |
1025 | } | |
1026 | ||
1027 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1028 | if (r) | |
1029 | goto out; | |
1030 | ||
6680073d | 1031 | pgpath->is_active = 1; |
1da177e4 | 1032 | |
e54f77dd CS |
1033 | if (!m->nr_valid_paths++ && m->queue_size) { |
1034 | m->current_pgpath = NULL; | |
c557308e | 1035 | queue_work(kmultipathd, &m->process_queued_ios); |
e54f77dd CS |
1036 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
1037 | if (queue_work(kmpath_handlerd, &pgpath->activate_path)) | |
1038 | m->pg_init_in_progress++; | |
1039 | } | |
1da177e4 | 1040 | |
b15546f9 MA |
1041 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
1042 | pgpath->path.dev->name, m->nr_valid_paths); | |
1043 | ||
fe9cf30e | 1044 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1045 | |
1046 | out: | |
1047 | spin_unlock_irqrestore(&m->lock, flags); | |
1048 | ||
1049 | return r; | |
1050 | } | |
1051 | ||
1052 | /* | |
1053 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1054 | */ | |
1055 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1056 | action_fn action) | |
1057 | { | |
1058 | int r = 0; | |
1059 | struct pgpath *pgpath; | |
1060 | struct priority_group *pg; | |
1061 | ||
1062 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1063 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1064 | if (pgpath->path.dev == dev) | |
1065 | r = action(pgpath); | |
1066 | } | |
1067 | } | |
1068 | ||
1069 | return r; | |
1070 | } | |
1071 | ||
1072 | /* | |
1073 | * Temporarily try to avoid having to use the specified PG | |
1074 | */ | |
1075 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
1076 | int bypassed) | |
1077 | { | |
1078 | unsigned long flags; | |
1079 | ||
1080 | spin_lock_irqsave(&m->lock, flags); | |
1081 | ||
1082 | pg->bypassed = bypassed; | |
1083 | m->current_pgpath = NULL; | |
1084 | m->current_pg = NULL; | |
1085 | ||
1086 | spin_unlock_irqrestore(&m->lock, flags); | |
1087 | ||
fe9cf30e | 1088 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1089 | } |
1090 | ||
1091 | /* | |
1092 | * Switch to using the specified PG from the next I/O that gets mapped | |
1093 | */ | |
1094 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1095 | { | |
1096 | struct priority_group *pg; | |
1097 | unsigned pgnum; | |
1098 | unsigned long flags; | |
1099 | ||
1100 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
1101 | (pgnum > m->nr_priority_groups)) { | |
1102 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1103 | return -EINVAL; | |
1104 | } | |
1105 | ||
1106 | spin_lock_irqsave(&m->lock, flags); | |
1107 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1108 | pg->bypassed = 0; | |
1109 | if (--pgnum) | |
1110 | continue; | |
1111 | ||
1112 | m->current_pgpath = NULL; | |
1113 | m->current_pg = NULL; | |
1114 | m->next_pg = pg; | |
1115 | } | |
1116 | spin_unlock_irqrestore(&m->lock, flags); | |
1117 | ||
fe9cf30e | 1118 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1119 | return 0; |
1120 | } | |
1121 | ||
1122 | /* | |
1123 | * Set/clear bypassed status of a PG. | |
1124 | * PGs are numbered upwards from 1 in the order they were declared. | |
1125 | */ | |
1126 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
1127 | { | |
1128 | struct priority_group *pg; | |
1129 | unsigned pgnum; | |
1130 | ||
1131 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
1132 | (pgnum > m->nr_priority_groups)) { | |
1133 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1134 | return -EINVAL; | |
1135 | } | |
1136 | ||
1137 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1138 | if (!--pgnum) | |
1139 | break; | |
1140 | } | |
1141 | ||
1142 | bypass_pg(m, pg, bypassed); | |
1143 | return 0; | |
1144 | } | |
1145 | ||
c9e45581 DW |
1146 | /* |
1147 | * Should we retry pg_init immediately? | |
1148 | */ | |
1149 | static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) | |
1150 | { | |
1151 | unsigned long flags; | |
1152 | int limit_reached = 0; | |
1153 | ||
1154 | spin_lock_irqsave(&m->lock, flags); | |
1155 | ||
1156 | if (m->pg_init_count <= m->pg_init_retries) | |
1157 | m->pg_init_required = 1; | |
1158 | else | |
1159 | limit_reached = 1; | |
1160 | ||
1161 | spin_unlock_irqrestore(&m->lock, flags); | |
1162 | ||
1163 | return limit_reached; | |
1164 | } | |
1165 | ||
3ae31f6a | 1166 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1167 | { |
83c0d5d5 | 1168 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1169 | struct priority_group *pg = pgpath->pg; |
1170 | struct multipath *m = pg->m; | |
1171 | unsigned long flags; | |
1172 | ||
1173 | /* device or driver problems */ | |
1174 | switch (errors) { | |
1175 | case SCSI_DH_OK: | |
1176 | break; | |
1177 | case SCSI_DH_NOSYS: | |
1178 | if (!m->hw_handler_name) { | |
1179 | errors = 0; | |
1180 | break; | |
1181 | } | |
f7b934c8 MB |
1182 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1183 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1184 | /* |
1185 | * Fail path for now, so we do not ping pong | |
1186 | */ | |
1187 | fail_path(pgpath); | |
1188 | break; | |
1189 | case SCSI_DH_DEV_TEMP_BUSY: | |
1190 | /* | |
1191 | * Probably doing something like FW upgrade on the | |
1192 | * controller so try the other pg. | |
1193 | */ | |
1194 | bypass_pg(m, pg, 1); | |
1195 | break; | |
1196 | /* TODO: For SCSI_DH_RETRY we should wait a couple seconds */ | |
1197 | case SCSI_DH_RETRY: | |
1198 | case SCSI_DH_IMM_RETRY: | |
1199 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1200 | if (pg_init_limit_reached(m, pgpath)) | |
1201 | fail_path(pgpath); | |
1202 | errors = 0; | |
1203 | break; | |
1204 | default: | |
1205 | /* | |
1206 | * We probably do not want to fail the path for a device | |
1207 | * error, but this is what the old dm did. In future | |
1208 | * patches we can do more advanced handling. | |
1209 | */ | |
1210 | fail_path(pgpath); | |
1211 | } | |
1212 | ||
1213 | spin_lock_irqsave(&m->lock, flags); | |
1214 | if (errors) { | |
e54f77dd CS |
1215 | if (pgpath == m->current_pgpath) { |
1216 | DMERR("Could not failover device. Error %d.", errors); | |
1217 | m->current_pgpath = NULL; | |
1218 | m->current_pg = NULL; | |
1219 | } | |
d0259bf0 | 1220 | } else if (!m->pg_init_required) |
cfae5c9b | 1221 | pg->bypassed = 0; |
cfae5c9b | 1222 | |
d0259bf0 KU |
1223 | if (--m->pg_init_in_progress) |
1224 | /* Activations of other paths are still on going */ | |
1225 | goto out; | |
1226 | ||
1227 | if (!m->pg_init_required) | |
1228 | m->queue_io = 0; | |
1229 | ||
1230 | queue_work(kmultipathd, &m->process_queued_ios); | |
1231 | ||
2bded7bd KU |
1232 | /* |
1233 | * Wake up any thread waiting to suspend. | |
1234 | */ | |
1235 | wake_up(&m->pg_init_wait); | |
1236 | ||
d0259bf0 | 1237 | out: |
cfae5c9b CS |
1238 | spin_unlock_irqrestore(&m->lock, flags); |
1239 | } | |
1240 | ||
bab7cfc7 CS |
1241 | static void activate_path(struct work_struct *work) |
1242 | { | |
e54f77dd CS |
1243 | struct pgpath *pgpath = |
1244 | container_of(work, struct pgpath, activate_path); | |
bab7cfc7 | 1245 | |
3ae31f6a | 1246 | scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev), |
83c0d5d5 | 1247 | pg_init_done, pgpath); |
bab7cfc7 CS |
1248 | } |
1249 | ||
1da177e4 LT |
1250 | /* |
1251 | * end_io handling | |
1252 | */ | |
f40c67f0 | 1253 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1254 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1255 | { |
f40c67f0 KU |
1256 | /* |
1257 | * We don't queue any clone request inside the multipath target | |
1258 | * during end I/O handling, since those clone requests don't have | |
1259 | * bio clones. If we queue them inside the multipath target, | |
1260 | * we need to make bio clones, that requires memory allocation. | |
1261 | * (See drivers/md/dm.c:end_clone_bio() about why the clone requests | |
1262 | * don't have bio clones.) | |
1263 | * Instead of queueing the clone request here, we queue the original | |
1264 | * request into dm core, which will remake a clone request and | |
1265 | * clone bios for it and resubmit it later. | |
1266 | */ | |
1267 | int r = DM_ENDIO_REQUEUE; | |
640eb3b0 | 1268 | unsigned long flags; |
1da177e4 | 1269 | |
f40c67f0 | 1270 | if (!error && !clone->errors) |
1da177e4 LT |
1271 | return 0; /* I/O complete */ |
1272 | ||
f6a80ea8 AK |
1273 | if (error == -EOPNOTSUPP) |
1274 | return error; | |
1275 | ||
959eb4e5 MS |
1276 | if (clone->cmd_flags & REQ_DISCARD) |
1277 | /* | |
1278 | * Pass all discard request failures up. | |
1279 | * FIXME: only fail_path if the discard failed due to a | |
1280 | * transport problem. This requires precise understanding | |
1281 | * of the underlying failure (e.g. the SCSI sense). | |
1282 | */ | |
1283 | return error; | |
1284 | ||
cfae5c9b CS |
1285 | if (mpio->pgpath) |
1286 | fail_path(mpio->pgpath); | |
1da177e4 | 1287 | |
640eb3b0 | 1288 | spin_lock_irqsave(&m->lock, flags); |
f40c67f0 KU |
1289 | if (!m->nr_valid_paths && !m->queue_if_no_path && !__must_push_back(m)) |
1290 | r = -EIO; | |
640eb3b0 | 1291 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 | 1292 | |
f40c67f0 | 1293 | return r; |
1da177e4 LT |
1294 | } |
1295 | ||
f40c67f0 | 1296 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1297 | int error, union map_info *map_context) |
1298 | { | |
028867ac AK |
1299 | struct multipath *m = ti->private; |
1300 | struct dm_mpath_io *mpio = map_context->ptr; | |
1da177e4 LT |
1301 | struct pgpath *pgpath = mpio->pgpath; |
1302 | struct path_selector *ps; | |
1303 | int r; | |
1304 | ||
f40c67f0 | 1305 | r = do_end_io(m, clone, error, mpio); |
1da177e4 LT |
1306 | if (pgpath) { |
1307 | ps = &pgpath->pg->ps; | |
1308 | if (ps->type->end_io) | |
02ab823f | 1309 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1310 | } |
f40c67f0 | 1311 | mempool_free(mpio, m->mpio_pool); |
1da177e4 LT |
1312 | |
1313 | return r; | |
1314 | } | |
1315 | ||
1316 | /* | |
1317 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1318 | * the last path fails we must error any remaining I/O. |
1319 | * Note that if the freeze_bdev fails while suspending, the | |
1320 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1321 | */ |
1322 | static void multipath_presuspend(struct dm_target *ti) | |
1323 | { | |
1324 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 | 1325 | |
485ef69e | 1326 | queue_if_no_path(m, 0, 1); |
1da177e4 LT |
1327 | } |
1328 | ||
6df400ab KU |
1329 | static void multipath_postsuspend(struct dm_target *ti) |
1330 | { | |
6380f26f MA |
1331 | struct multipath *m = ti->private; |
1332 | ||
1333 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1334 | flush_multipath_work(m); |
6380f26f | 1335 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1336 | } |
1337 | ||
436d4108 AK |
1338 | /* |
1339 | * Restore the queue_if_no_path setting. | |
1340 | */ | |
1da177e4 LT |
1341 | static void multipath_resume(struct dm_target *ti) |
1342 | { | |
1343 | struct multipath *m = (struct multipath *) ti->private; | |
1344 | unsigned long flags; | |
1345 | ||
1346 | spin_lock_irqsave(&m->lock, flags); | |
436d4108 | 1347 | m->queue_if_no_path = m->saved_queue_if_no_path; |
1da177e4 LT |
1348 | spin_unlock_irqrestore(&m->lock, flags); |
1349 | } | |
1350 | ||
1351 | /* | |
1352 | * Info output has the following format: | |
1353 | * num_multipath_feature_args [multipath_feature_args]* | |
1354 | * num_handler_status_args [handler_status_args]* | |
1355 | * num_groups init_group_number | |
1356 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1357 | * num_paths num_selector_args | |
1358 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1359 | * | |
1360 | * Table output has the following format (identical to the constructor string): | |
1361 | * num_feature_args [features_args]* | |
1362 | * num_handler_args hw_handler [hw_handler_args]* | |
1363 | * num_groups init_group_number | |
1364 | * [priority selector-name num_ps_args [ps_args]* | |
1365 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1366 | */ | |
1367 | static int multipath_status(struct dm_target *ti, status_type_t type, | |
1368 | char *result, unsigned int maxlen) | |
1369 | { | |
1370 | int sz = 0; | |
1371 | unsigned long flags; | |
1372 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 LT |
1373 | struct priority_group *pg; |
1374 | struct pgpath *p; | |
1375 | unsigned pg_num; | |
1376 | char state; | |
1377 | ||
1378 | spin_lock_irqsave(&m->lock, flags); | |
1379 | ||
1380 | /* Features */ | |
1381 | if (type == STATUSTYPE_INFO) | |
c9e45581 DW |
1382 | DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count); |
1383 | else { | |
1384 | DMEMIT("%u ", m->queue_if_no_path + | |
1385 | (m->pg_init_retries > 0) * 2); | |
1386 | if (m->queue_if_no_path) | |
1387 | DMEMIT("queue_if_no_path "); | |
1388 | if (m->pg_init_retries) | |
1389 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
1390 | } | |
1da177e4 | 1391 | |
cfae5c9b | 1392 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1393 | DMEMIT("0 "); |
1394 | else | |
cfae5c9b | 1395 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1396 | |
1397 | DMEMIT("%u ", m->nr_priority_groups); | |
1398 | ||
1399 | if (m->next_pg) | |
1400 | pg_num = m->next_pg->pg_num; | |
1401 | else if (m->current_pg) | |
1402 | pg_num = m->current_pg->pg_num; | |
1403 | else | |
1404 | pg_num = 1; | |
1405 | ||
1406 | DMEMIT("%u ", pg_num); | |
1407 | ||
1408 | switch (type) { | |
1409 | case STATUSTYPE_INFO: | |
1410 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1411 | if (pg->bypassed) | |
1412 | state = 'D'; /* Disabled */ | |
1413 | else if (pg == m->current_pg) | |
1414 | state = 'A'; /* Currently Active */ | |
1415 | else | |
1416 | state = 'E'; /* Enabled */ | |
1417 | ||
1418 | DMEMIT("%c ", state); | |
1419 | ||
1420 | if (pg->ps.type->status) | |
1421 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1422 | result + sz, | |
1423 | maxlen - sz); | |
1424 | else | |
1425 | DMEMIT("0 "); | |
1426 | ||
1427 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1428 | pg->ps.type->info_args); | |
1429 | ||
1430 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1431 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1432 | p->is_active ? "A" : "F", |
1da177e4 LT |
1433 | p->fail_count); |
1434 | if (pg->ps.type->status) | |
1435 | sz += pg->ps.type->status(&pg->ps, | |
1436 | &p->path, type, result + sz, | |
1437 | maxlen - sz); | |
1438 | } | |
1439 | } | |
1440 | break; | |
1441 | ||
1442 | case STATUSTYPE_TABLE: | |
1443 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1444 | DMEMIT("%s ", pg->ps.type->name); | |
1445 | ||
1446 | if (pg->ps.type->status) | |
1447 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1448 | result + sz, | |
1449 | maxlen - sz); | |
1450 | else | |
1451 | DMEMIT("0 "); | |
1452 | ||
1453 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1454 | pg->ps.type->table_args); | |
1455 | ||
1456 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1457 | DMEMIT("%s ", p->path.dev->name); | |
1458 | if (pg->ps.type->status) | |
1459 | sz += pg->ps.type->status(&pg->ps, | |
1460 | &p->path, type, result + sz, | |
1461 | maxlen - sz); | |
1462 | } | |
1463 | } | |
1464 | break; | |
1465 | } | |
1466 | ||
1467 | spin_unlock_irqrestore(&m->lock, flags); | |
1468 | ||
1469 | return 0; | |
1470 | } | |
1471 | ||
1472 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1473 | { | |
6380f26f | 1474 | int r = -EINVAL; |
1da177e4 LT |
1475 | struct dm_dev *dev; |
1476 | struct multipath *m = (struct multipath *) ti->private; | |
1477 | action_fn action; | |
1478 | ||
6380f26f MA |
1479 | mutex_lock(&m->work_mutex); |
1480 | ||
c2f3d24b KU |
1481 | if (dm_suspended(ti)) { |
1482 | r = -EBUSY; | |
1483 | goto out; | |
1484 | } | |
1485 | ||
1da177e4 | 1486 | if (argc == 1) { |
6380f26f MA |
1487 | if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) { |
1488 | r = queue_if_no_path(m, 1, 0); | |
1489 | goto out; | |
1490 | } else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) { | |
1491 | r = queue_if_no_path(m, 0, 0); | |
1492 | goto out; | |
1493 | } | |
1da177e4 LT |
1494 | } |
1495 | ||
6380f26f MA |
1496 | if (argc != 2) { |
1497 | DMWARN("Unrecognised multipath message received."); | |
1498 | goto out; | |
1499 | } | |
1da177e4 | 1500 | |
6380f26f MA |
1501 | if (!strnicmp(argv[0], MESG_STR("disable_group"))) { |
1502 | r = bypass_pg_num(m, argv[1], 1); | |
1503 | goto out; | |
1504 | } else if (!strnicmp(argv[0], MESG_STR("enable_group"))) { | |
1505 | r = bypass_pg_num(m, argv[1], 0); | |
1506 | goto out; | |
1507 | } else if (!strnicmp(argv[0], MESG_STR("switch_group"))) { | |
1508 | r = switch_pg_num(m, argv[1]); | |
1509 | goto out; | |
1510 | } else if (!strnicmp(argv[0], MESG_STR("reinstate_path"))) | |
1da177e4 LT |
1511 | action = reinstate_path; |
1512 | else if (!strnicmp(argv[0], MESG_STR("fail_path"))) | |
1513 | action = fail_path; | |
6380f26f MA |
1514 | else { |
1515 | DMWARN("Unrecognised multipath message received."); | |
1516 | goto out; | |
1517 | } | |
1da177e4 | 1518 | |
8215d6ec | 1519 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1520 | if (r) { |
72d94861 | 1521 | DMWARN("message: error getting device %s", |
1da177e4 | 1522 | argv[1]); |
6380f26f | 1523 | goto out; |
1da177e4 LT |
1524 | } |
1525 | ||
1526 | r = action_dev(m, dev, action); | |
1527 | ||
1528 | dm_put_device(ti, dev); | |
1529 | ||
6380f26f MA |
1530 | out: |
1531 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1532 | return r; |
1da177e4 LT |
1533 | } |
1534 | ||
647b3d00 | 1535 | static int multipath_ioctl(struct dm_target *ti, unsigned int cmd, |
9af4aa30 MB |
1536 | unsigned long arg) |
1537 | { | |
1538 | struct multipath *m = (struct multipath *) ti->private; | |
1539 | struct block_device *bdev = NULL; | |
633a08b8 | 1540 | fmode_t mode = 0; |
9af4aa30 MB |
1541 | unsigned long flags; |
1542 | int r = 0; | |
1543 | ||
1544 | spin_lock_irqsave(&m->lock, flags); | |
1545 | ||
1546 | if (!m->current_pgpath) | |
02ab823f | 1547 | __choose_pgpath(m, 0); |
9af4aa30 | 1548 | |
e90dae1f | 1549 | if (m->current_pgpath) { |
9af4aa30 | 1550 | bdev = m->current_pgpath->path.dev->bdev; |
633a08b8 | 1551 | mode = m->current_pgpath->path.dev->mode; |
e90dae1f | 1552 | } |
9af4aa30 MB |
1553 | |
1554 | if (m->queue_io) | |
1555 | r = -EAGAIN; | |
1556 | else if (!bdev) | |
1557 | r = -EIO; | |
1558 | ||
1559 | spin_unlock_irqrestore(&m->lock, flags); | |
1560 | ||
633a08b8 | 1561 | return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg); |
9af4aa30 MB |
1562 | } |
1563 | ||
af4874e0 MS |
1564 | static int multipath_iterate_devices(struct dm_target *ti, |
1565 | iterate_devices_callout_fn fn, void *data) | |
1566 | { | |
1567 | struct multipath *m = ti->private; | |
1568 | struct priority_group *pg; | |
1569 | struct pgpath *p; | |
1570 | int ret = 0; | |
1571 | ||
1572 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1573 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1574 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1575 | if (ret) |
1576 | goto out; | |
1577 | } | |
1578 | } | |
1579 | ||
1580 | out: | |
1581 | return ret; | |
1582 | } | |
1583 | ||
f40c67f0 KU |
1584 | static int __pgpath_busy(struct pgpath *pgpath) |
1585 | { | |
1586 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1587 | ||
1588 | return dm_underlying_device_busy(q); | |
1589 | } | |
1590 | ||
1591 | /* | |
1592 | * We return "busy", only when we can map I/Os but underlying devices | |
1593 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1594 | * the underlying queue). | |
1595 | * In other words, if we want to kill I/Os or queue them inside us | |
1596 | * due to map unavailability, we don't return "busy". Otherwise, | |
1597 | * dm core won't give us the I/Os and we can't do what we want. | |
1598 | */ | |
1599 | static int multipath_busy(struct dm_target *ti) | |
1600 | { | |
1601 | int busy = 0, has_active = 0; | |
1602 | struct multipath *m = ti->private; | |
1603 | struct priority_group *pg; | |
1604 | struct pgpath *pgpath; | |
1605 | unsigned long flags; | |
1606 | ||
1607 | spin_lock_irqsave(&m->lock, flags); | |
1608 | ||
1609 | /* Guess which priority_group will be used at next mapping time */ | |
1610 | if (unlikely(!m->current_pgpath && m->next_pg)) | |
1611 | pg = m->next_pg; | |
1612 | else if (likely(m->current_pg)) | |
1613 | pg = m->current_pg; | |
1614 | else | |
1615 | /* | |
1616 | * We don't know which pg will be used at next mapping time. | |
1617 | * We don't call __choose_pgpath() here to avoid to trigger | |
1618 | * pg_init just by busy checking. | |
1619 | * So we don't know whether underlying devices we will be using | |
1620 | * at next mapping time are busy or not. Just try mapping. | |
1621 | */ | |
1622 | goto out; | |
1623 | ||
1624 | /* | |
1625 | * If there is one non-busy active path at least, the path selector | |
1626 | * will be able to select it. So we consider such a pg as not busy. | |
1627 | */ | |
1628 | busy = 1; | |
1629 | list_for_each_entry(pgpath, &pg->pgpaths, list) | |
1630 | if (pgpath->is_active) { | |
1631 | has_active = 1; | |
1632 | ||
1633 | if (!__pgpath_busy(pgpath)) { | |
1634 | busy = 0; | |
1635 | break; | |
1636 | } | |
1637 | } | |
1638 | ||
1639 | if (!has_active) | |
1640 | /* | |
1641 | * No active path in this pg, so this pg won't be used and | |
1642 | * the current_pg will be changed at next mapping time. | |
1643 | * We need to try mapping to determine it. | |
1644 | */ | |
1645 | busy = 0; | |
1646 | ||
1647 | out: | |
1648 | spin_unlock_irqrestore(&m->lock, flags); | |
1649 | ||
1650 | return busy; | |
1651 | } | |
1652 | ||
1da177e4 LT |
1653 | /*----------------------------------------------------------------- |
1654 | * Module setup | |
1655 | *---------------------------------------------------------------*/ | |
1656 | static struct target_type multipath_target = { | |
1657 | .name = "multipath", | |
6df400ab | 1658 | .version = {1, 1, 1}, |
1da177e4 LT |
1659 | .module = THIS_MODULE, |
1660 | .ctr = multipath_ctr, | |
1661 | .dtr = multipath_dtr, | |
f40c67f0 KU |
1662 | .map_rq = multipath_map, |
1663 | .rq_end_io = multipath_end_io, | |
1da177e4 | 1664 | .presuspend = multipath_presuspend, |
6df400ab | 1665 | .postsuspend = multipath_postsuspend, |
1da177e4 LT |
1666 | .resume = multipath_resume, |
1667 | .status = multipath_status, | |
1668 | .message = multipath_message, | |
9af4aa30 | 1669 | .ioctl = multipath_ioctl, |
af4874e0 | 1670 | .iterate_devices = multipath_iterate_devices, |
f40c67f0 | 1671 | .busy = multipath_busy, |
1da177e4 LT |
1672 | }; |
1673 | ||
1674 | static int __init dm_multipath_init(void) | |
1675 | { | |
1676 | int r; | |
1677 | ||
1678 | /* allocate a slab for the dm_ios */ | |
028867ac | 1679 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
1680 | if (!_mpio_cache) |
1681 | return -ENOMEM; | |
1682 | ||
1683 | r = dm_register_target(&multipath_target); | |
1684 | if (r < 0) { | |
0cd33124 | 1685 | DMERR("register failed %d", r); |
1da177e4 LT |
1686 | kmem_cache_destroy(_mpio_cache); |
1687 | return -EINVAL; | |
1688 | } | |
1689 | ||
c557308e AK |
1690 | kmultipathd = create_workqueue("kmpathd"); |
1691 | if (!kmultipathd) { | |
0cd33124 | 1692 | DMERR("failed to create workqueue kmpathd"); |
c557308e AK |
1693 | dm_unregister_target(&multipath_target); |
1694 | kmem_cache_destroy(_mpio_cache); | |
1695 | return -ENOMEM; | |
1696 | } | |
1697 | ||
bab7cfc7 CS |
1698 | /* |
1699 | * A separate workqueue is used to handle the device handlers | |
1700 | * to avoid overloading existing workqueue. Overloading the | |
1701 | * old workqueue would also create a bottleneck in the | |
1702 | * path of the storage hardware device activation. | |
1703 | */ | |
1704 | kmpath_handlerd = create_singlethread_workqueue("kmpath_handlerd"); | |
1705 | if (!kmpath_handlerd) { | |
1706 | DMERR("failed to create workqueue kmpath_handlerd"); | |
1707 | destroy_workqueue(kmultipathd); | |
1708 | dm_unregister_target(&multipath_target); | |
1709 | kmem_cache_destroy(_mpio_cache); | |
1710 | return -ENOMEM; | |
1711 | } | |
1712 | ||
72d94861 | 1713 | DMINFO("version %u.%u.%u loaded", |
1da177e4 LT |
1714 | multipath_target.version[0], multipath_target.version[1], |
1715 | multipath_target.version[2]); | |
1716 | ||
1717 | return r; | |
1718 | } | |
1719 | ||
1720 | static void __exit dm_multipath_exit(void) | |
1721 | { | |
bab7cfc7 | 1722 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
1723 | destroy_workqueue(kmultipathd); |
1724 | ||
10d3bd09 | 1725 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
1726 | kmem_cache_destroy(_mpio_cache); |
1727 | } | |
1728 | ||
1da177e4 LT |
1729 | module_init(dm_multipath_init); |
1730 | module_exit(dm_multipath_exit); | |
1731 | ||
1732 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1733 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1734 | MODULE_LICENSE("GPL"); |