]>
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 | 25 | #define MESG_STR(x) x, sizeof(x) |
4e2d19e4 CS |
26 | #define DM_PG_INIT_DELAY_MSECS 2000 |
27 | #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1) | |
1da177e4 LT |
28 | |
29 | /* Path properties */ | |
30 | struct pgpath { | |
31 | struct list_head list; | |
32 | ||
33 | struct priority_group *pg; /* Owning PG */ | |
6680073d | 34 | unsigned is_active; /* Path status */ |
1da177e4 LT |
35 | unsigned fail_count; /* Cumulative failure count */ |
36 | ||
c922d5f7 | 37 | struct dm_path path; |
4e2d19e4 | 38 | struct delayed_work activate_path; |
1da177e4 LT |
39 | }; |
40 | ||
41 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
42 | ||
43 | /* | |
44 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
45 | * Each has a path selector which controls which path gets used. | |
46 | */ | |
47 | struct priority_group { | |
48 | struct list_head list; | |
49 | ||
50 | struct multipath *m; /* Owning multipath instance */ | |
51 | struct path_selector ps; | |
52 | ||
53 | unsigned pg_num; /* Reference number */ | |
54 | unsigned bypassed; /* Temporarily bypass this PG? */ | |
55 | ||
56 | unsigned nr_pgpaths; /* Number of paths in PG */ | |
57 | struct list_head pgpaths; | |
58 | }; | |
59 | ||
60 | /* Multipath context */ | |
61 | struct multipath { | |
62 | struct list_head list; | |
63 | struct dm_target *ti; | |
64 | ||
65 | spinlock_t lock; | |
66 | ||
cfae5c9b | 67 | const char *hw_handler_name; |
2bfd2e13 | 68 | char *hw_handler_params; |
4e2d19e4 | 69 | |
1da177e4 LT |
70 | unsigned nr_priority_groups; |
71 | struct list_head priority_groups; | |
4e2d19e4 CS |
72 | |
73 | wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ | |
74 | ||
1da177e4 | 75 | unsigned pg_init_required; /* pg_init needs calling? */ |
c3cd4f6b | 76 | unsigned pg_init_in_progress; /* Only one pg_init allowed at once */ |
4e2d19e4 | 77 | unsigned pg_init_delay_retry; /* Delay pg_init retry? */ |
1da177e4 LT |
78 | |
79 | unsigned nr_valid_paths; /* Total number of usable paths */ | |
80 | struct pgpath *current_pgpath; | |
81 | struct priority_group *current_pg; | |
82 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
83 | unsigned repeat_count; /* I/Os left before calling PS again */ | |
84 | ||
85 | unsigned queue_io; /* Must we queue all I/O? */ | |
86 | unsigned queue_if_no_path; /* Queue I/O if last path fails? */ | |
436d4108 | 87 | unsigned saved_queue_if_no_path;/* Saved state during suspension */ |
c9e45581 DW |
88 | unsigned pg_init_retries; /* Number of times to retry pg_init */ |
89 | unsigned pg_init_count; /* Number of times pg_init called */ | |
4e2d19e4 | 90 | unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */ |
1da177e4 LT |
91 | |
92 | struct work_struct process_queued_ios; | |
f40c67f0 | 93 | struct list_head queued_ios; |
1da177e4 LT |
94 | unsigned queue_size; |
95 | ||
96 | struct work_struct trigger_event; | |
97 | ||
98 | /* | |
028867ac | 99 | * We must use a mempool of dm_mpath_io structs so that we |
1da177e4 LT |
100 | * can resubmit bios on error. |
101 | */ | |
102 | mempool_t *mpio_pool; | |
6380f26f MA |
103 | |
104 | struct mutex work_mutex; | |
1da177e4 LT |
105 | }; |
106 | ||
107 | /* | |
108 | * Context information attached to each bio we process. | |
109 | */ | |
028867ac | 110 | struct dm_mpath_io { |
1da177e4 | 111 | struct pgpath *pgpath; |
02ab823f | 112 | size_t nr_bytes; |
1da177e4 LT |
113 | }; |
114 | ||
115 | typedef int (*action_fn) (struct pgpath *pgpath); | |
116 | ||
117 | #define MIN_IOS 256 /* Mempool size */ | |
118 | ||
e18b890b | 119 | static struct kmem_cache *_mpio_cache; |
1da177e4 | 120 | |
bab7cfc7 | 121 | static struct workqueue_struct *kmultipathd, *kmpath_handlerd; |
c4028958 DH |
122 | static void process_queued_ios(struct work_struct *work); |
123 | static void trigger_event(struct work_struct *work); | |
bab7cfc7 | 124 | static void activate_path(struct work_struct *work); |
1da177e4 LT |
125 | |
126 | ||
127 | /*----------------------------------------------- | |
128 | * Allocation routines | |
129 | *-----------------------------------------------*/ | |
130 | ||
131 | static struct pgpath *alloc_pgpath(void) | |
132 | { | |
e69fae56 | 133 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); |
1da177e4 | 134 | |
224cb3e9 | 135 | if (pgpath) { |
6680073d | 136 | pgpath->is_active = 1; |
4e2d19e4 | 137 | INIT_DELAYED_WORK(&pgpath->activate_path, activate_path); |
224cb3e9 | 138 | } |
1da177e4 LT |
139 | |
140 | return pgpath; | |
141 | } | |
142 | ||
028867ac | 143 | static void free_pgpath(struct pgpath *pgpath) |
1da177e4 LT |
144 | { |
145 | kfree(pgpath); | |
146 | } | |
147 | ||
148 | static struct priority_group *alloc_priority_group(void) | |
149 | { | |
150 | struct priority_group *pg; | |
151 | ||
e69fae56 | 152 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); |
1da177e4 | 153 | |
e69fae56 MM |
154 | if (pg) |
155 | INIT_LIST_HEAD(&pg->pgpaths); | |
1da177e4 LT |
156 | |
157 | return pg; | |
158 | } | |
159 | ||
160 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
161 | { | |
162 | struct pgpath *pgpath, *tmp; | |
ae11b1b3 | 163 | struct multipath *m = ti->private; |
1da177e4 LT |
164 | |
165 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
166 | list_del(&pgpath->list); | |
ae11b1b3 HR |
167 | if (m->hw_handler_name) |
168 | scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev)); | |
1da177e4 LT |
169 | dm_put_device(ti, pgpath->path.dev); |
170 | free_pgpath(pgpath); | |
171 | } | |
172 | } | |
173 | ||
174 | static void free_priority_group(struct priority_group *pg, | |
175 | struct dm_target *ti) | |
176 | { | |
177 | struct path_selector *ps = &pg->ps; | |
178 | ||
179 | if (ps->type) { | |
180 | ps->type->destroy(ps); | |
181 | dm_put_path_selector(ps->type); | |
182 | } | |
183 | ||
184 | free_pgpaths(&pg->pgpaths, ti); | |
185 | kfree(pg); | |
186 | } | |
187 | ||
28f16c20 | 188 | static struct multipath *alloc_multipath(struct dm_target *ti) |
1da177e4 LT |
189 | { |
190 | struct multipath *m; | |
191 | ||
e69fae56 | 192 | m = kzalloc(sizeof(*m), GFP_KERNEL); |
1da177e4 | 193 | if (m) { |
1da177e4 | 194 | INIT_LIST_HEAD(&m->priority_groups); |
f40c67f0 | 195 | INIT_LIST_HEAD(&m->queued_ios); |
1da177e4 LT |
196 | spin_lock_init(&m->lock); |
197 | m->queue_io = 1; | |
4e2d19e4 | 198 | m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; |
c4028958 DH |
199 | INIT_WORK(&m->process_queued_ios, process_queued_ios); |
200 | INIT_WORK(&m->trigger_event, trigger_event); | |
2bded7bd | 201 | init_waitqueue_head(&m->pg_init_wait); |
6380f26f | 202 | mutex_init(&m->work_mutex); |
93d2341c | 203 | m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache); |
1da177e4 LT |
204 | if (!m->mpio_pool) { |
205 | kfree(m); | |
206 | return NULL; | |
207 | } | |
28f16c20 MM |
208 | m->ti = ti; |
209 | ti->private = m; | |
1da177e4 LT |
210 | } |
211 | ||
212 | return m; | |
213 | } | |
214 | ||
215 | static void free_multipath(struct multipath *m) | |
216 | { | |
217 | struct priority_group *pg, *tmp; | |
1da177e4 LT |
218 | |
219 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
220 | list_del(&pg->list); | |
221 | free_priority_group(pg, m->ti); | |
222 | } | |
223 | ||
cfae5c9b | 224 | kfree(m->hw_handler_name); |
2bfd2e13 | 225 | kfree(m->hw_handler_params); |
1da177e4 LT |
226 | mempool_destroy(m->mpio_pool); |
227 | kfree(m); | |
228 | } | |
229 | ||
230 | ||
231 | /*----------------------------------------------- | |
232 | * Path selection | |
233 | *-----------------------------------------------*/ | |
234 | ||
fb612642 KU |
235 | static void __pg_init_all_paths(struct multipath *m) |
236 | { | |
237 | struct pgpath *pgpath; | |
4e2d19e4 | 238 | unsigned long pg_init_delay = 0; |
fb612642 KU |
239 | |
240 | m->pg_init_count++; | |
241 | m->pg_init_required = 0; | |
4e2d19e4 CS |
242 | if (m->pg_init_delay_retry) |
243 | pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ? | |
244 | m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS); | |
fb612642 KU |
245 | list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) { |
246 | /* Skip failed paths */ | |
247 | if (!pgpath->is_active) | |
248 | continue; | |
4e2d19e4 CS |
249 | if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path, |
250 | pg_init_delay)) | |
fb612642 KU |
251 | m->pg_init_in_progress++; |
252 | } | |
253 | } | |
254 | ||
1da177e4 LT |
255 | static void __switch_pg(struct multipath *m, struct pgpath *pgpath) |
256 | { | |
1da177e4 LT |
257 | m->current_pg = pgpath->pg; |
258 | ||
259 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
cfae5c9b | 260 | if (m->hw_handler_name) { |
1da177e4 LT |
261 | m->pg_init_required = 1; |
262 | m->queue_io = 1; | |
263 | } else { | |
264 | m->pg_init_required = 0; | |
265 | m->queue_io = 0; | |
266 | } | |
c9e45581 DW |
267 | |
268 | m->pg_init_count = 0; | |
1da177e4 LT |
269 | } |
270 | ||
02ab823f KU |
271 | static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg, |
272 | size_t nr_bytes) | |
1da177e4 | 273 | { |
c922d5f7 | 274 | struct dm_path *path; |
1da177e4 | 275 | |
02ab823f | 276 | path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes); |
1da177e4 LT |
277 | if (!path) |
278 | return -ENXIO; | |
279 | ||
280 | m->current_pgpath = path_to_pgpath(path); | |
281 | ||
282 | if (m->current_pg != pg) | |
283 | __switch_pg(m, m->current_pgpath); | |
284 | ||
285 | return 0; | |
286 | } | |
287 | ||
02ab823f | 288 | static void __choose_pgpath(struct multipath *m, size_t nr_bytes) |
1da177e4 LT |
289 | { |
290 | struct priority_group *pg; | |
291 | unsigned bypassed = 1; | |
292 | ||
293 | if (!m->nr_valid_paths) | |
294 | goto failed; | |
295 | ||
296 | /* Were we instructed to switch PG? */ | |
297 | if (m->next_pg) { | |
298 | pg = m->next_pg; | |
299 | m->next_pg = NULL; | |
02ab823f | 300 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
301 | return; |
302 | } | |
303 | ||
304 | /* Don't change PG until it has no remaining paths */ | |
02ab823f | 305 | if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes)) |
1da177e4 LT |
306 | return; |
307 | ||
308 | /* | |
309 | * Loop through priority groups until we find a valid path. | |
310 | * First time we skip PGs marked 'bypassed'. | |
311 | * Second time we only try the ones we skipped. | |
312 | */ | |
313 | do { | |
314 | list_for_each_entry(pg, &m->priority_groups, list) { | |
315 | if (pg->bypassed == bypassed) | |
316 | continue; | |
02ab823f | 317 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
318 | return; |
319 | } | |
320 | } while (bypassed--); | |
321 | ||
322 | failed: | |
323 | m->current_pgpath = NULL; | |
324 | m->current_pg = NULL; | |
325 | } | |
326 | ||
45e15720 KU |
327 | /* |
328 | * Check whether bios must be queued in the device-mapper core rather | |
329 | * than here in the target. | |
330 | * | |
331 | * m->lock must be held on entry. | |
332 | * | |
333 | * If m->queue_if_no_path and m->saved_queue_if_no_path hold the | |
334 | * same value then we are not between multipath_presuspend() | |
335 | * and multipath_resume() calls and we have no need to check | |
336 | * for the DMF_NOFLUSH_SUSPENDING flag. | |
337 | */ | |
338 | static int __must_push_back(struct multipath *m) | |
339 | { | |
340 | return (m->queue_if_no_path != m->saved_queue_if_no_path && | |
341 | dm_noflush_suspending(m->ti)); | |
342 | } | |
343 | ||
f40c67f0 | 344 | static int map_io(struct multipath *m, struct request *clone, |
028867ac | 345 | struct dm_mpath_io *mpio, unsigned was_queued) |
1da177e4 | 346 | { |
d2a7ad29 | 347 | int r = DM_MAPIO_REMAPPED; |
f40c67f0 | 348 | size_t nr_bytes = blk_rq_bytes(clone); |
1da177e4 LT |
349 | unsigned long flags; |
350 | struct pgpath *pgpath; | |
f40c67f0 | 351 | struct block_device *bdev; |
1da177e4 LT |
352 | |
353 | spin_lock_irqsave(&m->lock, flags); | |
354 | ||
355 | /* Do we need to select a new pgpath? */ | |
356 | if (!m->current_pgpath || | |
357 | (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) | |
02ab823f | 358 | __choose_pgpath(m, nr_bytes); |
1da177e4 LT |
359 | |
360 | pgpath = m->current_pgpath; | |
361 | ||
362 | if (was_queued) | |
363 | m->queue_size--; | |
364 | ||
365 | if ((pgpath && m->queue_io) || | |
436d4108 | 366 | (!pgpath && m->queue_if_no_path)) { |
1da177e4 | 367 | /* Queue for the daemon to resubmit */ |
f40c67f0 | 368 | list_add_tail(&clone->queuelist, &m->queued_ios); |
1da177e4 | 369 | m->queue_size++; |
c3cd4f6b AK |
370 | if ((m->pg_init_required && !m->pg_init_in_progress) || |
371 | !m->queue_io) | |
c557308e | 372 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 | 373 | pgpath = NULL; |
d2a7ad29 | 374 | r = DM_MAPIO_SUBMITTED; |
f40c67f0 KU |
375 | } else if (pgpath) { |
376 | bdev = pgpath->path.dev->bdev; | |
377 | clone->q = bdev_get_queue(bdev); | |
378 | clone->rq_disk = bdev->bd_disk; | |
379 | } else if (__must_push_back(m)) | |
45e15720 KU |
380 | r = DM_MAPIO_REQUEUE; |
381 | else | |
382 | r = -EIO; /* Failed */ | |
1da177e4 LT |
383 | |
384 | mpio->pgpath = pgpath; | |
02ab823f KU |
385 | mpio->nr_bytes = nr_bytes; |
386 | ||
387 | if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io) | |
388 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path, | |
389 | nr_bytes); | |
1da177e4 LT |
390 | |
391 | spin_unlock_irqrestore(&m->lock, flags); | |
392 | ||
393 | return r; | |
394 | } | |
395 | ||
396 | /* | |
397 | * If we run out of usable paths, should we queue I/O or error it? | |
398 | */ | |
485ef69e AK |
399 | static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path, |
400 | unsigned save_old_value) | |
1da177e4 LT |
401 | { |
402 | unsigned long flags; | |
403 | ||
404 | spin_lock_irqsave(&m->lock, flags); | |
405 | ||
485ef69e AK |
406 | if (save_old_value) |
407 | m->saved_queue_if_no_path = m->queue_if_no_path; | |
408 | else | |
409 | m->saved_queue_if_no_path = queue_if_no_path; | |
1da177e4 | 410 | m->queue_if_no_path = queue_if_no_path; |
c3cd4f6b | 411 | if (!m->queue_if_no_path && m->queue_size) |
c557308e | 412 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
413 | |
414 | spin_unlock_irqrestore(&m->lock, flags); | |
415 | ||
416 | return 0; | |
417 | } | |
418 | ||
419 | /*----------------------------------------------------------------- | |
420 | * The multipath daemon is responsible for resubmitting queued ios. | |
421 | *---------------------------------------------------------------*/ | |
422 | ||
423 | static void dispatch_queued_ios(struct multipath *m) | |
424 | { | |
425 | int r; | |
426 | unsigned long flags; | |
028867ac | 427 | struct dm_mpath_io *mpio; |
1da177e4 | 428 | union map_info *info; |
f40c67f0 KU |
429 | struct request *clone, *n; |
430 | LIST_HEAD(cl); | |
1da177e4 LT |
431 | |
432 | spin_lock_irqsave(&m->lock, flags); | |
f40c67f0 | 433 | list_splice_init(&m->queued_ios, &cl); |
1da177e4 LT |
434 | spin_unlock_irqrestore(&m->lock, flags); |
435 | ||
f40c67f0 KU |
436 | list_for_each_entry_safe(clone, n, &cl, queuelist) { |
437 | list_del_init(&clone->queuelist); | |
1da177e4 | 438 | |
f40c67f0 | 439 | info = dm_get_rq_mapinfo(clone); |
1da177e4 LT |
440 | mpio = info->ptr; |
441 | ||
f40c67f0 KU |
442 | r = map_io(m, clone, mpio, 1); |
443 | if (r < 0) { | |
444 | mempool_free(mpio, m->mpio_pool); | |
445 | dm_kill_unmapped_request(clone, r); | |
446 | } else if (r == DM_MAPIO_REMAPPED) | |
447 | dm_dispatch_request(clone); | |
448 | else if (r == DM_MAPIO_REQUEUE) { | |
449 | mempool_free(mpio, m->mpio_pool); | |
450 | dm_requeue_unmapped_request(clone); | |
451 | } | |
1da177e4 LT |
452 | } |
453 | } | |
454 | ||
c4028958 | 455 | static void process_queued_ios(struct work_struct *work) |
1da177e4 | 456 | { |
c4028958 DH |
457 | struct multipath *m = |
458 | container_of(work, struct multipath, process_queued_ios); | |
fb612642 | 459 | struct pgpath *pgpath = NULL; |
e54f77dd | 460 | unsigned must_queue = 1; |
1da177e4 LT |
461 | unsigned long flags; |
462 | ||
463 | spin_lock_irqsave(&m->lock, flags); | |
464 | ||
c3cd4f6b AK |
465 | if (!m->queue_size) |
466 | goto out; | |
467 | ||
1da177e4 | 468 | if (!m->current_pgpath) |
02ab823f | 469 | __choose_pgpath(m, 0); |
1da177e4 LT |
470 | |
471 | pgpath = m->current_pgpath; | |
472 | ||
c3cd4f6b AK |
473 | if ((pgpath && !m->queue_io) || |
474 | (!pgpath && !m->queue_if_no_path)) | |
475 | must_queue = 0; | |
1da177e4 | 476 | |
fb612642 KU |
477 | if (m->pg_init_required && !m->pg_init_in_progress && pgpath) |
478 | __pg_init_all_paths(m); | |
479 | ||
c3cd4f6b | 480 | out: |
1da177e4 | 481 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 LT |
482 | if (!must_queue) |
483 | dispatch_queued_ios(m); | |
484 | } | |
485 | ||
486 | /* | |
487 | * An event is triggered whenever a path is taken out of use. | |
488 | * Includes path failure and PG bypass. | |
489 | */ | |
c4028958 | 490 | static void trigger_event(struct work_struct *work) |
1da177e4 | 491 | { |
c4028958 DH |
492 | struct multipath *m = |
493 | container_of(work, struct multipath, trigger_event); | |
1da177e4 LT |
494 | |
495 | dm_table_event(m->ti->table); | |
496 | } | |
497 | ||
498 | /*----------------------------------------------------------------- | |
499 | * Constructor/argument parsing: | |
500 | * <#multipath feature args> [<arg>]* | |
501 | * <#hw_handler args> [hw_handler [<arg>]*] | |
502 | * <#priority groups> | |
503 | * <initial priority group> | |
504 | * [<selector> <#selector args> [<arg>]* | |
505 | * <#paths> <#per-path selector args> | |
506 | * [<path> [<arg>]* ]+ ]+ | |
507 | *---------------------------------------------------------------*/ | |
508 | struct param { | |
509 | unsigned min; | |
510 | unsigned max; | |
511 | char *error; | |
512 | }; | |
513 | ||
1da177e4 LT |
514 | static int read_param(struct param *param, char *str, unsigned *v, char **error) |
515 | { | |
516 | if (!str || | |
517 | (sscanf(str, "%u", v) != 1) || | |
518 | (*v < param->min) || | |
519 | (*v > param->max)) { | |
520 | *error = param->error; | |
521 | return -EINVAL; | |
522 | } | |
523 | ||
524 | return 0; | |
525 | } | |
526 | ||
527 | struct arg_set { | |
528 | unsigned argc; | |
529 | char **argv; | |
530 | }; | |
531 | ||
532 | static char *shift(struct arg_set *as) | |
533 | { | |
534 | char *r; | |
535 | ||
536 | if (as->argc) { | |
537 | as->argc--; | |
538 | r = *as->argv; | |
539 | as->argv++; | |
540 | return r; | |
541 | } | |
542 | ||
543 | return NULL; | |
544 | } | |
545 | ||
546 | static void consume(struct arg_set *as, unsigned n) | |
547 | { | |
548 | BUG_ON (as->argc < n); | |
549 | as->argc -= n; | |
550 | as->argv += n; | |
551 | } | |
552 | ||
553 | static int parse_path_selector(struct arg_set *as, struct priority_group *pg, | |
554 | struct dm_target *ti) | |
555 | { | |
556 | int r; | |
557 | struct path_selector_type *pst; | |
558 | unsigned ps_argc; | |
559 | ||
560 | static struct param _params[] = { | |
72d94861 | 561 | {0, 1024, "invalid number of path selector args"}, |
1da177e4 LT |
562 | }; |
563 | ||
564 | pst = dm_get_path_selector(shift(as)); | |
565 | if (!pst) { | |
72d94861 | 566 | ti->error = "unknown path selector type"; |
1da177e4 LT |
567 | return -EINVAL; |
568 | } | |
569 | ||
570 | r = read_param(_params, shift(as), &ps_argc, &ti->error); | |
371b2e34 MP |
571 | if (r) { |
572 | dm_put_path_selector(pst); | |
1da177e4 | 573 | return -EINVAL; |
371b2e34 | 574 | } |
1da177e4 | 575 | |
0e0497c0 MP |
576 | if (ps_argc > as->argc) { |
577 | dm_put_path_selector(pst); | |
578 | ti->error = "not enough arguments for path selector"; | |
579 | return -EINVAL; | |
580 | } | |
581 | ||
1da177e4 LT |
582 | r = pst->create(&pg->ps, ps_argc, as->argv); |
583 | if (r) { | |
584 | dm_put_path_selector(pst); | |
72d94861 | 585 | ti->error = "path selector constructor failed"; |
1da177e4 LT |
586 | return r; |
587 | } | |
588 | ||
589 | pg->ps.type = pst; | |
590 | consume(as, ps_argc); | |
591 | ||
592 | return 0; | |
593 | } | |
594 | ||
595 | static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps, | |
596 | struct dm_target *ti) | |
597 | { | |
598 | int r; | |
599 | struct pgpath *p; | |
ae11b1b3 | 600 | struct multipath *m = ti->private; |
1da177e4 LT |
601 | |
602 | /* we need at least a path arg */ | |
603 | if (as->argc < 1) { | |
72d94861 | 604 | ti->error = "no device given"; |
01460f35 | 605 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
606 | } |
607 | ||
608 | p = alloc_pgpath(); | |
609 | if (!p) | |
01460f35 | 610 | return ERR_PTR(-ENOMEM); |
1da177e4 | 611 | |
8215d6ec NK |
612 | r = dm_get_device(ti, shift(as), dm_table_get_mode(ti->table), |
613 | &p->path.dev); | |
1da177e4 | 614 | if (r) { |
72d94861 | 615 | ti->error = "error getting device"; |
1da177e4 LT |
616 | goto bad; |
617 | } | |
618 | ||
ae11b1b3 | 619 | if (m->hw_handler_name) { |
a0cf7ea9 HR |
620 | struct request_queue *q = bdev_get_queue(p->path.dev->bdev); |
621 | ||
622 | r = scsi_dh_attach(q, m->hw_handler_name); | |
623 | if (r == -EBUSY) { | |
624 | /* | |
625 | * Already attached to different hw_handler, | |
626 | * try to reattach with correct one. | |
627 | */ | |
628 | scsi_dh_detach(q); | |
629 | r = scsi_dh_attach(q, m->hw_handler_name); | |
630 | } | |
631 | ||
ae11b1b3 | 632 | if (r < 0) { |
a0cf7ea9 | 633 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
634 | dm_put_device(ti, p->path.dev); |
635 | goto bad; | |
636 | } | |
2bfd2e13 CS |
637 | |
638 | if (m->hw_handler_params) { | |
639 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
640 | if (r < 0) { | |
641 | ti->error = "unable to set hardware " | |
642 | "handler parameters"; | |
643 | scsi_dh_detach(q); | |
644 | dm_put_device(ti, p->path.dev); | |
645 | goto bad; | |
646 | } | |
647 | } | |
ae11b1b3 HR |
648 | } |
649 | ||
1da177e4 LT |
650 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
651 | if (r) { | |
652 | dm_put_device(ti, p->path.dev); | |
653 | goto bad; | |
654 | } | |
655 | ||
656 | return p; | |
657 | ||
658 | bad: | |
659 | free_pgpath(p); | |
01460f35 | 660 | return ERR_PTR(r); |
1da177e4 LT |
661 | } |
662 | ||
663 | static struct priority_group *parse_priority_group(struct arg_set *as, | |
28f16c20 | 664 | struct multipath *m) |
1da177e4 LT |
665 | { |
666 | static struct param _params[] = { | |
72d94861 AK |
667 | {1, 1024, "invalid number of paths"}, |
668 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
669 | }; |
670 | ||
671 | int r; | |
672 | unsigned i, nr_selector_args, nr_params; | |
673 | struct priority_group *pg; | |
28f16c20 | 674 | struct dm_target *ti = m->ti; |
1da177e4 LT |
675 | |
676 | if (as->argc < 2) { | |
677 | as->argc = 0; | |
01460f35 BM |
678 | ti->error = "not enough priority group arguments"; |
679 | return ERR_PTR(-EINVAL); | |
1da177e4 LT |
680 | } |
681 | ||
682 | pg = alloc_priority_group(); | |
683 | if (!pg) { | |
72d94861 | 684 | ti->error = "couldn't allocate priority group"; |
01460f35 | 685 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
686 | } |
687 | pg->m = m; | |
688 | ||
689 | r = parse_path_selector(as, pg, ti); | |
690 | if (r) | |
691 | goto bad; | |
692 | ||
693 | /* | |
694 | * read the paths | |
695 | */ | |
696 | r = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error); | |
697 | if (r) | |
698 | goto bad; | |
699 | ||
700 | r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error); | |
701 | if (r) | |
702 | goto bad; | |
703 | ||
704 | nr_params = 1 + nr_selector_args; | |
705 | for (i = 0; i < pg->nr_pgpaths; i++) { | |
706 | struct pgpath *pgpath; | |
707 | struct arg_set path_args; | |
708 | ||
148acff6 MP |
709 | if (as->argc < nr_params) { |
710 | ti->error = "not enough path parameters"; | |
6bbf79a1 | 711 | r = -EINVAL; |
1da177e4 | 712 | goto bad; |
148acff6 | 713 | } |
1da177e4 LT |
714 | |
715 | path_args.argc = nr_params; | |
716 | path_args.argv = as->argv; | |
717 | ||
718 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
719 | if (IS_ERR(pgpath)) { |
720 | r = PTR_ERR(pgpath); | |
1da177e4 | 721 | goto bad; |
01460f35 | 722 | } |
1da177e4 LT |
723 | |
724 | pgpath->pg = pg; | |
725 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
726 | consume(as, nr_params); | |
727 | } | |
728 | ||
729 | return pg; | |
730 | ||
731 | bad: | |
732 | free_priority_group(pg, ti); | |
01460f35 | 733 | return ERR_PTR(r); |
1da177e4 LT |
734 | } |
735 | ||
28f16c20 | 736 | static int parse_hw_handler(struct arg_set *as, struct multipath *m) |
1da177e4 | 737 | { |
1da177e4 | 738 | unsigned hw_argc; |
2bfd2e13 | 739 | int ret; |
28f16c20 | 740 | struct dm_target *ti = m->ti; |
1da177e4 LT |
741 | |
742 | static struct param _params[] = { | |
72d94861 | 743 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
744 | }; |
745 | ||
cfae5c9b | 746 | if (read_param(_params, shift(as), &hw_argc, &ti->error)) |
1da177e4 LT |
747 | return -EINVAL; |
748 | ||
749 | if (!hw_argc) | |
750 | return 0; | |
751 | ||
e094f4f1 MP |
752 | if (hw_argc > as->argc) { |
753 | ti->error = "not enough arguments for hardware handler"; | |
754 | return -EINVAL; | |
755 | } | |
756 | ||
cfae5c9b CS |
757 | m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL); |
758 | request_module("scsi_dh_%s", m->hw_handler_name); | |
759 | if (scsi_dh_handler_exist(m->hw_handler_name) == 0) { | |
72d94861 | 760 | ti->error = "unknown hardware handler type"; |
2bfd2e13 CS |
761 | ret = -EINVAL; |
762 | goto fail; | |
1da177e4 | 763 | } |
14e98c5c | 764 | |
2bfd2e13 CS |
765 | if (hw_argc > 1) { |
766 | char *p; | |
767 | int i, j, len = 4; | |
768 | ||
769 | for (i = 0; i <= hw_argc - 2; i++) | |
770 | len += strlen(as->argv[i]) + 1; | |
771 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
772 | if (!p) { | |
773 | ti->error = "memory allocation failed"; | |
774 | ret = -ENOMEM; | |
775 | goto fail; | |
776 | } | |
777 | j = sprintf(p, "%d", hw_argc - 1); | |
778 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
779 | j = sprintf(p, "%s", as->argv[i]); | |
780 | } | |
1da177e4 LT |
781 | consume(as, hw_argc - 1); |
782 | ||
783 | return 0; | |
2bfd2e13 CS |
784 | fail: |
785 | kfree(m->hw_handler_name); | |
786 | m->hw_handler_name = NULL; | |
787 | return ret; | |
1da177e4 LT |
788 | } |
789 | ||
28f16c20 | 790 | static int parse_features(struct arg_set *as, struct multipath *m) |
1da177e4 LT |
791 | { |
792 | int r; | |
793 | unsigned argc; | |
28f16c20 | 794 | struct dm_target *ti = m->ti; |
c9e45581 | 795 | const char *param_name; |
1da177e4 LT |
796 | |
797 | static struct param _params[] = { | |
4e2d19e4 | 798 | {0, 5, "invalid number of feature args"}, |
c9e45581 | 799 | {1, 50, "pg_init_retries must be between 1 and 50"}, |
4e2d19e4 | 800 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, |
1da177e4 LT |
801 | }; |
802 | ||
803 | r = read_param(_params, shift(as), &argc, &ti->error); | |
804 | if (r) | |
805 | return -EINVAL; | |
806 | ||
807 | if (!argc) | |
808 | return 0; | |
809 | ||
c9e45581 DW |
810 | do { |
811 | param_name = shift(as); | |
812 | argc--; | |
813 | ||
814 | if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) { | |
815 | r = queue_if_no_path(m, 1, 0); | |
816 | continue; | |
817 | } | |
818 | ||
819 | if (!strnicmp(param_name, MESG_STR("pg_init_retries")) && | |
820 | (argc >= 1)) { | |
821 | r = read_param(_params + 1, shift(as), | |
822 | &m->pg_init_retries, &ti->error); | |
823 | argc--; | |
824 | continue; | |
825 | } | |
826 | ||
4e2d19e4 CS |
827 | if (!strnicmp(param_name, MESG_STR("pg_init_delay_msecs")) && |
828 | (argc >= 1)) { | |
829 | r = read_param(_params + 2, shift(as), | |
830 | &m->pg_init_delay_msecs, &ti->error); | |
831 | argc--; | |
832 | continue; | |
833 | } | |
834 | ||
1da177e4 | 835 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
836 | r = -EINVAL; |
837 | } while (argc && !r); | |
838 | ||
839 | return r; | |
1da177e4 LT |
840 | } |
841 | ||
842 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
843 | char **argv) | |
844 | { | |
845 | /* target parameters */ | |
846 | static struct param _params[] = { | |
72d94861 AK |
847 | {1, 1024, "invalid number of priority groups"}, |
848 | {1, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
849 | }; |
850 | ||
851 | int r; | |
852 | struct multipath *m; | |
853 | struct arg_set as; | |
854 | unsigned pg_count = 0; | |
855 | unsigned next_pg_num; | |
856 | ||
857 | as.argc = argc; | |
858 | as.argv = argv; | |
859 | ||
28f16c20 | 860 | m = alloc_multipath(ti); |
1da177e4 | 861 | if (!m) { |
72d94861 | 862 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
863 | return -EINVAL; |
864 | } | |
865 | ||
28f16c20 | 866 | r = parse_features(&as, m); |
1da177e4 LT |
867 | if (r) |
868 | goto bad; | |
869 | ||
28f16c20 | 870 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
871 | if (r) |
872 | goto bad; | |
873 | ||
874 | r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error); | |
875 | if (r) | |
876 | goto bad; | |
877 | ||
878 | r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error); | |
879 | if (r) | |
880 | goto bad; | |
881 | ||
882 | /* parse the priority groups */ | |
883 | while (as.argc) { | |
884 | struct priority_group *pg; | |
885 | ||
28f16c20 | 886 | pg = parse_priority_group(&as, m); |
01460f35 BM |
887 | if (IS_ERR(pg)) { |
888 | r = PTR_ERR(pg); | |
1da177e4 LT |
889 | goto bad; |
890 | } | |
891 | ||
892 | m->nr_valid_paths += pg->nr_pgpaths; | |
893 | list_add_tail(&pg->list, &m->priority_groups); | |
894 | pg_count++; | |
895 | pg->pg_num = pg_count; | |
896 | if (!--next_pg_num) | |
897 | m->next_pg = pg; | |
898 | } | |
899 | ||
900 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 901 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
902 | r = -EINVAL; |
903 | goto bad; | |
904 | } | |
905 | ||
8627921f | 906 | ti->num_flush_requests = 1; |
959eb4e5 | 907 | ti->num_discard_requests = 1; |
8627921f | 908 | |
1da177e4 LT |
909 | return 0; |
910 | ||
911 | bad: | |
912 | free_multipath(m); | |
913 | return r; | |
914 | } | |
915 | ||
2bded7bd KU |
916 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
917 | { | |
918 | DECLARE_WAITQUEUE(wait, current); | |
919 | unsigned long flags; | |
920 | ||
921 | add_wait_queue(&m->pg_init_wait, &wait); | |
922 | ||
923 | while (1) { | |
924 | set_current_state(TASK_UNINTERRUPTIBLE); | |
925 | ||
926 | spin_lock_irqsave(&m->lock, flags); | |
927 | if (!m->pg_init_in_progress) { | |
928 | spin_unlock_irqrestore(&m->lock, flags); | |
929 | break; | |
930 | } | |
931 | spin_unlock_irqrestore(&m->lock, flags); | |
932 | ||
933 | io_schedule(); | |
934 | } | |
935 | set_current_state(TASK_RUNNING); | |
936 | ||
937 | remove_wait_queue(&m->pg_init_wait, &wait); | |
938 | } | |
939 | ||
940 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 941 | { |
bab7cfc7 | 942 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 943 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 944 | flush_workqueue(kmultipathd); |
d5ffa387 | 945 | flush_work_sync(&m->trigger_event); |
6df400ab KU |
946 | } |
947 | ||
948 | static void multipath_dtr(struct dm_target *ti) | |
949 | { | |
950 | struct multipath *m = ti->private; | |
951 | ||
2bded7bd | 952 | flush_multipath_work(m); |
1da177e4 LT |
953 | free_multipath(m); |
954 | } | |
955 | ||
956 | /* | |
f40c67f0 | 957 | * Map cloned requests |
1da177e4 | 958 | */ |
f40c67f0 | 959 | static int multipath_map(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
960 | union map_info *map_context) |
961 | { | |
962 | int r; | |
028867ac | 963 | struct dm_mpath_io *mpio; |
1da177e4 LT |
964 | struct multipath *m = (struct multipath *) ti->private; |
965 | ||
f40c67f0 KU |
966 | mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); |
967 | if (!mpio) | |
968 | /* ENOMEM, requeue */ | |
969 | return DM_MAPIO_REQUEUE; | |
970 | memset(mpio, 0, sizeof(*mpio)); | |
1da177e4 LT |
971 | |
972 | map_context->ptr = mpio; | |
f40c67f0 KU |
973 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; |
974 | r = map_io(m, clone, mpio, 0); | |
45e15720 | 975 | if (r < 0 || r == DM_MAPIO_REQUEUE) |
1da177e4 LT |
976 | mempool_free(mpio, m->mpio_pool); |
977 | ||
978 | return r; | |
979 | } | |
980 | ||
981 | /* | |
982 | * Take a path out of use. | |
983 | */ | |
984 | static int fail_path(struct pgpath *pgpath) | |
985 | { | |
986 | unsigned long flags; | |
987 | struct multipath *m = pgpath->pg->m; | |
988 | ||
989 | spin_lock_irqsave(&m->lock, flags); | |
990 | ||
6680073d | 991 | if (!pgpath->is_active) |
1da177e4 LT |
992 | goto out; |
993 | ||
72d94861 | 994 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
995 | |
996 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
6680073d | 997 | pgpath->is_active = 0; |
1da177e4 LT |
998 | pgpath->fail_count++; |
999 | ||
1000 | m->nr_valid_paths--; | |
1001 | ||
1002 | if (pgpath == m->current_pgpath) | |
1003 | m->current_pgpath = NULL; | |
1004 | ||
b15546f9 MA |
1005 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
1006 | pgpath->path.dev->name, m->nr_valid_paths); | |
1007 | ||
fe9cf30e | 1008 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1009 | |
1010 | out: | |
1011 | spin_unlock_irqrestore(&m->lock, flags); | |
1012 | ||
1013 | return 0; | |
1014 | } | |
1015 | ||
1016 | /* | |
1017 | * Reinstate a previously-failed path | |
1018 | */ | |
1019 | static int reinstate_path(struct pgpath *pgpath) | |
1020 | { | |
1021 | int r = 0; | |
1022 | unsigned long flags; | |
1023 | struct multipath *m = pgpath->pg->m; | |
1024 | ||
1025 | spin_lock_irqsave(&m->lock, flags); | |
1026 | ||
6680073d | 1027 | if (pgpath->is_active) |
1da177e4 LT |
1028 | goto out; |
1029 | ||
def052d2 | 1030 | if (!pgpath->pg->ps.type->reinstate_path) { |
1da177e4 LT |
1031 | DMWARN("Reinstate path not supported by path selector %s", |
1032 | pgpath->pg->ps.type->name); | |
1033 | r = -EINVAL; | |
1034 | goto out; | |
1035 | } | |
1036 | ||
1037 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1038 | if (r) | |
1039 | goto out; | |
1040 | ||
6680073d | 1041 | pgpath->is_active = 1; |
1da177e4 | 1042 | |
e54f77dd CS |
1043 | if (!m->nr_valid_paths++ && m->queue_size) { |
1044 | m->current_pgpath = NULL; | |
c557308e | 1045 | queue_work(kmultipathd, &m->process_queued_ios); |
e54f77dd | 1046 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
4e2d19e4 | 1047 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) |
e54f77dd CS |
1048 | m->pg_init_in_progress++; |
1049 | } | |
1da177e4 | 1050 | |
b15546f9 MA |
1051 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
1052 | pgpath->path.dev->name, m->nr_valid_paths); | |
1053 | ||
fe9cf30e | 1054 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1055 | |
1056 | out: | |
1057 | spin_unlock_irqrestore(&m->lock, flags); | |
1058 | ||
1059 | return r; | |
1060 | } | |
1061 | ||
1062 | /* | |
1063 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1064 | */ | |
1065 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1066 | action_fn action) | |
1067 | { | |
19040c0b | 1068 | int r = -EINVAL; |
1da177e4 LT |
1069 | struct pgpath *pgpath; |
1070 | struct priority_group *pg; | |
1071 | ||
1072 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1073 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1074 | if (pgpath->path.dev == dev) | |
1075 | r = action(pgpath); | |
1076 | } | |
1077 | } | |
1078 | ||
1079 | return r; | |
1080 | } | |
1081 | ||
1082 | /* | |
1083 | * Temporarily try to avoid having to use the specified PG | |
1084 | */ | |
1085 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
1086 | int bypassed) | |
1087 | { | |
1088 | unsigned long flags; | |
1089 | ||
1090 | spin_lock_irqsave(&m->lock, flags); | |
1091 | ||
1092 | pg->bypassed = bypassed; | |
1093 | m->current_pgpath = NULL; | |
1094 | m->current_pg = NULL; | |
1095 | ||
1096 | spin_unlock_irqrestore(&m->lock, flags); | |
1097 | ||
fe9cf30e | 1098 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1099 | } |
1100 | ||
1101 | /* | |
1102 | * Switch to using the specified PG from the next I/O that gets mapped | |
1103 | */ | |
1104 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1105 | { | |
1106 | struct priority_group *pg; | |
1107 | unsigned pgnum; | |
1108 | unsigned long flags; | |
1109 | ||
1110 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
1111 | (pgnum > m->nr_priority_groups)) { | |
1112 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1113 | return -EINVAL; | |
1114 | } | |
1115 | ||
1116 | spin_lock_irqsave(&m->lock, flags); | |
1117 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1118 | pg->bypassed = 0; | |
1119 | if (--pgnum) | |
1120 | continue; | |
1121 | ||
1122 | m->current_pgpath = NULL; | |
1123 | m->current_pg = NULL; | |
1124 | m->next_pg = pg; | |
1125 | } | |
1126 | spin_unlock_irqrestore(&m->lock, flags); | |
1127 | ||
fe9cf30e | 1128 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1129 | return 0; |
1130 | } | |
1131 | ||
1132 | /* | |
1133 | * Set/clear bypassed status of a PG. | |
1134 | * PGs are numbered upwards from 1 in the order they were declared. | |
1135 | */ | |
1136 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
1137 | { | |
1138 | struct priority_group *pg; | |
1139 | unsigned pgnum; | |
1140 | ||
1141 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
1142 | (pgnum > m->nr_priority_groups)) { | |
1143 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1144 | return -EINVAL; | |
1145 | } | |
1146 | ||
1147 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1148 | if (!--pgnum) | |
1149 | break; | |
1150 | } | |
1151 | ||
1152 | bypass_pg(m, pg, bypassed); | |
1153 | return 0; | |
1154 | } | |
1155 | ||
c9e45581 DW |
1156 | /* |
1157 | * Should we retry pg_init immediately? | |
1158 | */ | |
1159 | static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) | |
1160 | { | |
1161 | unsigned long flags; | |
1162 | int limit_reached = 0; | |
1163 | ||
1164 | spin_lock_irqsave(&m->lock, flags); | |
1165 | ||
1166 | if (m->pg_init_count <= m->pg_init_retries) | |
1167 | m->pg_init_required = 1; | |
1168 | else | |
1169 | limit_reached = 1; | |
1170 | ||
1171 | spin_unlock_irqrestore(&m->lock, flags); | |
1172 | ||
1173 | return limit_reached; | |
1174 | } | |
1175 | ||
3ae31f6a | 1176 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1177 | { |
83c0d5d5 | 1178 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1179 | struct priority_group *pg = pgpath->pg; |
1180 | struct multipath *m = pg->m; | |
1181 | unsigned long flags; | |
4e2d19e4 | 1182 | unsigned delay_retry = 0; |
cfae5c9b CS |
1183 | |
1184 | /* device or driver problems */ | |
1185 | switch (errors) { | |
1186 | case SCSI_DH_OK: | |
1187 | break; | |
1188 | case SCSI_DH_NOSYS: | |
1189 | if (!m->hw_handler_name) { | |
1190 | errors = 0; | |
1191 | break; | |
1192 | } | |
f7b934c8 MB |
1193 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1194 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1195 | /* |
1196 | * Fail path for now, so we do not ping pong | |
1197 | */ | |
1198 | fail_path(pgpath); | |
1199 | break; | |
1200 | case SCSI_DH_DEV_TEMP_BUSY: | |
1201 | /* | |
1202 | * Probably doing something like FW upgrade on the | |
1203 | * controller so try the other pg. | |
1204 | */ | |
1205 | bypass_pg(m, pg, 1); | |
1206 | break; | |
cfae5c9b | 1207 | case SCSI_DH_RETRY: |
4e2d19e4 CS |
1208 | /* Wait before retrying. */ |
1209 | delay_retry = 1; | |
cfae5c9b CS |
1210 | case SCSI_DH_IMM_RETRY: |
1211 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1212 | if (pg_init_limit_reached(m, pgpath)) | |
1213 | fail_path(pgpath); | |
1214 | errors = 0; | |
1215 | break; | |
1216 | default: | |
1217 | /* | |
1218 | * We probably do not want to fail the path for a device | |
1219 | * error, but this is what the old dm did. In future | |
1220 | * patches we can do more advanced handling. | |
1221 | */ | |
1222 | fail_path(pgpath); | |
1223 | } | |
1224 | ||
1225 | spin_lock_irqsave(&m->lock, flags); | |
1226 | if (errors) { | |
e54f77dd CS |
1227 | if (pgpath == m->current_pgpath) { |
1228 | DMERR("Could not failover device. Error %d.", errors); | |
1229 | m->current_pgpath = NULL; | |
1230 | m->current_pg = NULL; | |
1231 | } | |
d0259bf0 | 1232 | } else if (!m->pg_init_required) |
cfae5c9b | 1233 | pg->bypassed = 0; |
cfae5c9b | 1234 | |
d0259bf0 KU |
1235 | if (--m->pg_init_in_progress) |
1236 | /* Activations of other paths are still on going */ | |
1237 | goto out; | |
1238 | ||
1239 | if (!m->pg_init_required) | |
1240 | m->queue_io = 0; | |
1241 | ||
4e2d19e4 | 1242 | m->pg_init_delay_retry = delay_retry; |
d0259bf0 KU |
1243 | queue_work(kmultipathd, &m->process_queued_ios); |
1244 | ||
2bded7bd KU |
1245 | /* |
1246 | * Wake up any thread waiting to suspend. | |
1247 | */ | |
1248 | wake_up(&m->pg_init_wait); | |
1249 | ||
d0259bf0 | 1250 | out: |
cfae5c9b CS |
1251 | spin_unlock_irqrestore(&m->lock, flags); |
1252 | } | |
1253 | ||
bab7cfc7 CS |
1254 | static void activate_path(struct work_struct *work) |
1255 | { | |
e54f77dd | 1256 | struct pgpath *pgpath = |
4e2d19e4 | 1257 | container_of(work, struct pgpath, activate_path.work); |
bab7cfc7 | 1258 | |
3ae31f6a | 1259 | scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev), |
83c0d5d5 | 1260 | pg_init_done, pgpath); |
bab7cfc7 CS |
1261 | } |
1262 | ||
1da177e4 LT |
1263 | /* |
1264 | * end_io handling | |
1265 | */ | |
f40c67f0 | 1266 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1267 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1268 | { |
f40c67f0 KU |
1269 | /* |
1270 | * We don't queue any clone request inside the multipath target | |
1271 | * during end I/O handling, since those clone requests don't have | |
1272 | * bio clones. If we queue them inside the multipath target, | |
1273 | * we need to make bio clones, that requires memory allocation. | |
1274 | * (See drivers/md/dm.c:end_clone_bio() about why the clone requests | |
1275 | * don't have bio clones.) | |
1276 | * Instead of queueing the clone request here, we queue the original | |
1277 | * request into dm core, which will remake a clone request and | |
1278 | * clone bios for it and resubmit it later. | |
1279 | */ | |
1280 | int r = DM_ENDIO_REQUEUE; | |
640eb3b0 | 1281 | unsigned long flags; |
1da177e4 | 1282 | |
f40c67f0 | 1283 | if (!error && !clone->errors) |
1da177e4 LT |
1284 | return 0; /* I/O complete */ |
1285 | ||
751b2a7d | 1286 | if (error == -EOPNOTSUPP || error == -EREMOTEIO) |
959eb4e5 MS |
1287 | return error; |
1288 | ||
cfae5c9b CS |
1289 | if (mpio->pgpath) |
1290 | fail_path(mpio->pgpath); | |
1da177e4 | 1291 | |
640eb3b0 | 1292 | spin_lock_irqsave(&m->lock, flags); |
751b2a7d HR |
1293 | if (!m->nr_valid_paths) { |
1294 | if (!m->queue_if_no_path) { | |
1295 | if (!__must_push_back(m)) | |
1296 | r = -EIO; | |
1297 | } else { | |
1298 | if (error == -EBADE) | |
1299 | r = error; | |
1300 | } | |
1301 | } | |
640eb3b0 | 1302 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 | 1303 | |
f40c67f0 | 1304 | return r; |
1da177e4 LT |
1305 | } |
1306 | ||
f40c67f0 | 1307 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1308 | int error, union map_info *map_context) |
1309 | { | |
028867ac AK |
1310 | struct multipath *m = ti->private; |
1311 | struct dm_mpath_io *mpio = map_context->ptr; | |
1da177e4 LT |
1312 | struct pgpath *pgpath = mpio->pgpath; |
1313 | struct path_selector *ps; | |
1314 | int r; | |
1315 | ||
f40c67f0 | 1316 | r = do_end_io(m, clone, error, mpio); |
1da177e4 LT |
1317 | if (pgpath) { |
1318 | ps = &pgpath->pg->ps; | |
1319 | if (ps->type->end_io) | |
02ab823f | 1320 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1321 | } |
f40c67f0 | 1322 | mempool_free(mpio, m->mpio_pool); |
1da177e4 LT |
1323 | |
1324 | return r; | |
1325 | } | |
1326 | ||
1327 | /* | |
1328 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1329 | * the last path fails we must error any remaining I/O. |
1330 | * Note that if the freeze_bdev fails while suspending, the | |
1331 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1332 | */ |
1333 | static void multipath_presuspend(struct dm_target *ti) | |
1334 | { | |
1335 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 | 1336 | |
485ef69e | 1337 | queue_if_no_path(m, 0, 1); |
1da177e4 LT |
1338 | } |
1339 | ||
6df400ab KU |
1340 | static void multipath_postsuspend(struct dm_target *ti) |
1341 | { | |
6380f26f MA |
1342 | struct multipath *m = ti->private; |
1343 | ||
1344 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1345 | flush_multipath_work(m); |
6380f26f | 1346 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1347 | } |
1348 | ||
436d4108 AK |
1349 | /* |
1350 | * Restore the queue_if_no_path setting. | |
1351 | */ | |
1da177e4 LT |
1352 | static void multipath_resume(struct dm_target *ti) |
1353 | { | |
1354 | struct multipath *m = (struct multipath *) ti->private; | |
1355 | unsigned long flags; | |
1356 | ||
1357 | spin_lock_irqsave(&m->lock, flags); | |
436d4108 | 1358 | m->queue_if_no_path = m->saved_queue_if_no_path; |
1da177e4 LT |
1359 | spin_unlock_irqrestore(&m->lock, flags); |
1360 | } | |
1361 | ||
1362 | /* | |
1363 | * Info output has the following format: | |
1364 | * num_multipath_feature_args [multipath_feature_args]* | |
1365 | * num_handler_status_args [handler_status_args]* | |
1366 | * num_groups init_group_number | |
1367 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1368 | * num_paths num_selector_args | |
1369 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1370 | * | |
1371 | * Table output has the following format (identical to the constructor string): | |
1372 | * num_feature_args [features_args]* | |
1373 | * num_handler_args hw_handler [hw_handler_args]* | |
1374 | * num_groups init_group_number | |
1375 | * [priority selector-name num_ps_args [ps_args]* | |
1376 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1377 | */ | |
1378 | static int multipath_status(struct dm_target *ti, status_type_t type, | |
1379 | char *result, unsigned int maxlen) | |
1380 | { | |
1381 | int sz = 0; | |
1382 | unsigned long flags; | |
1383 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 LT |
1384 | struct priority_group *pg; |
1385 | struct pgpath *p; | |
1386 | unsigned pg_num; | |
1387 | char state; | |
1388 | ||
1389 | spin_lock_irqsave(&m->lock, flags); | |
1390 | ||
1391 | /* Features */ | |
1392 | if (type == STATUSTYPE_INFO) | |
c9e45581 DW |
1393 | DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count); |
1394 | else { | |
1395 | DMEMIT("%u ", m->queue_if_no_path + | |
4e2d19e4 CS |
1396 | (m->pg_init_retries > 0) * 2 + |
1397 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2); | |
c9e45581 DW |
1398 | if (m->queue_if_no_path) |
1399 | DMEMIT("queue_if_no_path "); | |
1400 | if (m->pg_init_retries) | |
1401 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
4e2d19e4 CS |
1402 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) |
1403 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); | |
c9e45581 | 1404 | } |
1da177e4 | 1405 | |
cfae5c9b | 1406 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1407 | DMEMIT("0 "); |
1408 | else | |
cfae5c9b | 1409 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1410 | |
1411 | DMEMIT("%u ", m->nr_priority_groups); | |
1412 | ||
1413 | if (m->next_pg) | |
1414 | pg_num = m->next_pg->pg_num; | |
1415 | else if (m->current_pg) | |
1416 | pg_num = m->current_pg->pg_num; | |
1417 | else | |
1418 | pg_num = 1; | |
1419 | ||
1420 | DMEMIT("%u ", pg_num); | |
1421 | ||
1422 | switch (type) { | |
1423 | case STATUSTYPE_INFO: | |
1424 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1425 | if (pg->bypassed) | |
1426 | state = 'D'; /* Disabled */ | |
1427 | else if (pg == m->current_pg) | |
1428 | state = 'A'; /* Currently Active */ | |
1429 | else | |
1430 | state = 'E'; /* Enabled */ | |
1431 | ||
1432 | DMEMIT("%c ", state); | |
1433 | ||
1434 | if (pg->ps.type->status) | |
1435 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1436 | result + sz, | |
1437 | maxlen - sz); | |
1438 | else | |
1439 | DMEMIT("0 "); | |
1440 | ||
1441 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1442 | pg->ps.type->info_args); | |
1443 | ||
1444 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1445 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1446 | p->is_active ? "A" : "F", |
1da177e4 LT |
1447 | p->fail_count); |
1448 | if (pg->ps.type->status) | |
1449 | sz += pg->ps.type->status(&pg->ps, | |
1450 | &p->path, type, result + sz, | |
1451 | maxlen - sz); | |
1452 | } | |
1453 | } | |
1454 | break; | |
1455 | ||
1456 | case STATUSTYPE_TABLE: | |
1457 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1458 | DMEMIT("%s ", pg->ps.type->name); | |
1459 | ||
1460 | if (pg->ps.type->status) | |
1461 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1462 | result + sz, | |
1463 | maxlen - sz); | |
1464 | else | |
1465 | DMEMIT("0 "); | |
1466 | ||
1467 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1468 | pg->ps.type->table_args); | |
1469 | ||
1470 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1471 | DMEMIT("%s ", p->path.dev->name); | |
1472 | if (pg->ps.type->status) | |
1473 | sz += pg->ps.type->status(&pg->ps, | |
1474 | &p->path, type, result + sz, | |
1475 | maxlen - sz); | |
1476 | } | |
1477 | } | |
1478 | break; | |
1479 | } | |
1480 | ||
1481 | spin_unlock_irqrestore(&m->lock, flags); | |
1482 | ||
1483 | return 0; | |
1484 | } | |
1485 | ||
1486 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1487 | { | |
6380f26f | 1488 | int r = -EINVAL; |
1da177e4 LT |
1489 | struct dm_dev *dev; |
1490 | struct multipath *m = (struct multipath *) ti->private; | |
1491 | action_fn action; | |
1492 | ||
6380f26f MA |
1493 | mutex_lock(&m->work_mutex); |
1494 | ||
c2f3d24b KU |
1495 | if (dm_suspended(ti)) { |
1496 | r = -EBUSY; | |
1497 | goto out; | |
1498 | } | |
1499 | ||
1da177e4 | 1500 | if (argc == 1) { |
6380f26f MA |
1501 | if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) { |
1502 | r = queue_if_no_path(m, 1, 0); | |
1503 | goto out; | |
1504 | } else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) { | |
1505 | r = queue_if_no_path(m, 0, 0); | |
1506 | goto out; | |
1507 | } | |
1da177e4 LT |
1508 | } |
1509 | ||
6380f26f MA |
1510 | if (argc != 2) { |
1511 | DMWARN("Unrecognised multipath message received."); | |
1512 | goto out; | |
1513 | } | |
1da177e4 | 1514 | |
6380f26f MA |
1515 | if (!strnicmp(argv[0], MESG_STR("disable_group"))) { |
1516 | r = bypass_pg_num(m, argv[1], 1); | |
1517 | goto out; | |
1518 | } else if (!strnicmp(argv[0], MESG_STR("enable_group"))) { | |
1519 | r = bypass_pg_num(m, argv[1], 0); | |
1520 | goto out; | |
1521 | } else if (!strnicmp(argv[0], MESG_STR("switch_group"))) { | |
1522 | r = switch_pg_num(m, argv[1]); | |
1523 | goto out; | |
1524 | } else if (!strnicmp(argv[0], MESG_STR("reinstate_path"))) | |
1da177e4 LT |
1525 | action = reinstate_path; |
1526 | else if (!strnicmp(argv[0], MESG_STR("fail_path"))) | |
1527 | action = fail_path; | |
6380f26f MA |
1528 | else { |
1529 | DMWARN("Unrecognised multipath message received."); | |
1530 | goto out; | |
1531 | } | |
1da177e4 | 1532 | |
8215d6ec | 1533 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1534 | if (r) { |
72d94861 | 1535 | DMWARN("message: error getting device %s", |
1da177e4 | 1536 | argv[1]); |
6380f26f | 1537 | goto out; |
1da177e4 LT |
1538 | } |
1539 | ||
1540 | r = action_dev(m, dev, action); | |
1541 | ||
1542 | dm_put_device(ti, dev); | |
1543 | ||
6380f26f MA |
1544 | out: |
1545 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1546 | return r; |
1da177e4 LT |
1547 | } |
1548 | ||
647b3d00 | 1549 | static int multipath_ioctl(struct dm_target *ti, unsigned int cmd, |
9af4aa30 MB |
1550 | unsigned long arg) |
1551 | { | |
1552 | struct multipath *m = (struct multipath *) ti->private; | |
1553 | struct block_device *bdev = NULL; | |
633a08b8 | 1554 | fmode_t mode = 0; |
9af4aa30 MB |
1555 | unsigned long flags; |
1556 | int r = 0; | |
1557 | ||
1558 | spin_lock_irqsave(&m->lock, flags); | |
1559 | ||
1560 | if (!m->current_pgpath) | |
02ab823f | 1561 | __choose_pgpath(m, 0); |
9af4aa30 | 1562 | |
e90dae1f | 1563 | if (m->current_pgpath) { |
9af4aa30 | 1564 | bdev = m->current_pgpath->path.dev->bdev; |
633a08b8 | 1565 | mode = m->current_pgpath->path.dev->mode; |
e90dae1f | 1566 | } |
9af4aa30 MB |
1567 | |
1568 | if (m->queue_io) | |
1569 | r = -EAGAIN; | |
1570 | else if (!bdev) | |
1571 | r = -EIO; | |
1572 | ||
1573 | spin_unlock_irqrestore(&m->lock, flags); | |
1574 | ||
633a08b8 | 1575 | return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg); |
9af4aa30 MB |
1576 | } |
1577 | ||
af4874e0 MS |
1578 | static int multipath_iterate_devices(struct dm_target *ti, |
1579 | iterate_devices_callout_fn fn, void *data) | |
1580 | { | |
1581 | struct multipath *m = ti->private; | |
1582 | struct priority_group *pg; | |
1583 | struct pgpath *p; | |
1584 | int ret = 0; | |
1585 | ||
1586 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1587 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1588 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1589 | if (ret) |
1590 | goto out; | |
1591 | } | |
1592 | } | |
1593 | ||
1594 | out: | |
1595 | return ret; | |
1596 | } | |
1597 | ||
f40c67f0 KU |
1598 | static int __pgpath_busy(struct pgpath *pgpath) |
1599 | { | |
1600 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1601 | ||
1602 | return dm_underlying_device_busy(q); | |
1603 | } | |
1604 | ||
1605 | /* | |
1606 | * We return "busy", only when we can map I/Os but underlying devices | |
1607 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1608 | * the underlying queue). | |
1609 | * In other words, if we want to kill I/Os or queue them inside us | |
1610 | * due to map unavailability, we don't return "busy". Otherwise, | |
1611 | * dm core won't give us the I/Os and we can't do what we want. | |
1612 | */ | |
1613 | static int multipath_busy(struct dm_target *ti) | |
1614 | { | |
1615 | int busy = 0, has_active = 0; | |
1616 | struct multipath *m = ti->private; | |
1617 | struct priority_group *pg; | |
1618 | struct pgpath *pgpath; | |
1619 | unsigned long flags; | |
1620 | ||
1621 | spin_lock_irqsave(&m->lock, flags); | |
1622 | ||
1623 | /* Guess which priority_group will be used at next mapping time */ | |
1624 | if (unlikely(!m->current_pgpath && m->next_pg)) | |
1625 | pg = m->next_pg; | |
1626 | else if (likely(m->current_pg)) | |
1627 | pg = m->current_pg; | |
1628 | else | |
1629 | /* | |
1630 | * We don't know which pg will be used at next mapping time. | |
1631 | * We don't call __choose_pgpath() here to avoid to trigger | |
1632 | * pg_init just by busy checking. | |
1633 | * So we don't know whether underlying devices we will be using | |
1634 | * at next mapping time are busy or not. Just try mapping. | |
1635 | */ | |
1636 | goto out; | |
1637 | ||
1638 | /* | |
1639 | * If there is one non-busy active path at least, the path selector | |
1640 | * will be able to select it. So we consider such a pg as not busy. | |
1641 | */ | |
1642 | busy = 1; | |
1643 | list_for_each_entry(pgpath, &pg->pgpaths, list) | |
1644 | if (pgpath->is_active) { | |
1645 | has_active = 1; | |
1646 | ||
1647 | if (!__pgpath_busy(pgpath)) { | |
1648 | busy = 0; | |
1649 | break; | |
1650 | } | |
1651 | } | |
1652 | ||
1653 | if (!has_active) | |
1654 | /* | |
1655 | * No active path in this pg, so this pg won't be used and | |
1656 | * the current_pg will be changed at next mapping time. | |
1657 | * We need to try mapping to determine it. | |
1658 | */ | |
1659 | busy = 0; | |
1660 | ||
1661 | out: | |
1662 | spin_unlock_irqrestore(&m->lock, flags); | |
1663 | ||
1664 | return busy; | |
1665 | } | |
1666 | ||
1da177e4 LT |
1667 | /*----------------------------------------------------------------- |
1668 | * Module setup | |
1669 | *---------------------------------------------------------------*/ | |
1670 | static struct target_type multipath_target = { | |
1671 | .name = "multipath", | |
19040c0b | 1672 | .version = {1, 3, 0}, |
1da177e4 LT |
1673 | .module = THIS_MODULE, |
1674 | .ctr = multipath_ctr, | |
1675 | .dtr = multipath_dtr, | |
f40c67f0 KU |
1676 | .map_rq = multipath_map, |
1677 | .rq_end_io = multipath_end_io, | |
1da177e4 | 1678 | .presuspend = multipath_presuspend, |
6df400ab | 1679 | .postsuspend = multipath_postsuspend, |
1da177e4 LT |
1680 | .resume = multipath_resume, |
1681 | .status = multipath_status, | |
1682 | .message = multipath_message, | |
9af4aa30 | 1683 | .ioctl = multipath_ioctl, |
af4874e0 | 1684 | .iterate_devices = multipath_iterate_devices, |
f40c67f0 | 1685 | .busy = multipath_busy, |
1da177e4 LT |
1686 | }; |
1687 | ||
1688 | static int __init dm_multipath_init(void) | |
1689 | { | |
1690 | int r; | |
1691 | ||
1692 | /* allocate a slab for the dm_ios */ | |
028867ac | 1693 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
1694 | if (!_mpio_cache) |
1695 | return -ENOMEM; | |
1696 | ||
1697 | r = dm_register_target(&multipath_target); | |
1698 | if (r < 0) { | |
0cd33124 | 1699 | DMERR("register failed %d", r); |
1da177e4 LT |
1700 | kmem_cache_destroy(_mpio_cache); |
1701 | return -EINVAL; | |
1702 | } | |
1703 | ||
4d4d66ab | 1704 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); |
c557308e | 1705 | if (!kmultipathd) { |
0cd33124 | 1706 | DMERR("failed to create workqueue kmpathd"); |
c557308e AK |
1707 | dm_unregister_target(&multipath_target); |
1708 | kmem_cache_destroy(_mpio_cache); | |
1709 | return -ENOMEM; | |
1710 | } | |
1711 | ||
bab7cfc7 CS |
1712 | /* |
1713 | * A separate workqueue is used to handle the device handlers | |
1714 | * to avoid overloading existing workqueue. Overloading the | |
1715 | * old workqueue would also create a bottleneck in the | |
1716 | * path of the storage hardware device activation. | |
1717 | */ | |
4d4d66ab TH |
1718 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", |
1719 | WQ_MEM_RECLAIM); | |
bab7cfc7 CS |
1720 | if (!kmpath_handlerd) { |
1721 | DMERR("failed to create workqueue kmpath_handlerd"); | |
1722 | destroy_workqueue(kmultipathd); | |
1723 | dm_unregister_target(&multipath_target); | |
1724 | kmem_cache_destroy(_mpio_cache); | |
1725 | return -ENOMEM; | |
1726 | } | |
1727 | ||
72d94861 | 1728 | DMINFO("version %u.%u.%u loaded", |
1da177e4 LT |
1729 | multipath_target.version[0], multipath_target.version[1], |
1730 | multipath_target.version[2]); | |
1731 | ||
1732 | return r; | |
1733 | } | |
1734 | ||
1735 | static void __exit dm_multipath_exit(void) | |
1736 | { | |
bab7cfc7 | 1737 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
1738 | destroy_workqueue(kmultipathd); |
1739 | ||
10d3bd09 | 1740 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
1741 | kmem_cache_destroy(_mpio_cache); |
1742 | } | |
1743 | ||
1da177e4 LT |
1744 | module_init(dm_multipath_init); |
1745 | module_exit(dm_multipath_exit); | |
1746 | ||
1747 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1748 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1749 | MODULE_LICENSE("GPL"); |