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1 | /* | |
2 | * Copyright (C) 2002 Sistina Software (UK) Limited. | |
3 | * Copyright (C) 2006 Red Hat GmbH | |
4 | * | |
5 | * This file is released under the GPL. | |
6 | * | |
7 | * Kcopyd provides a simple interface for copying an area of one | |
8 | * block-device to one or more other block-devices, with an asynchronous | |
9 | * completion notification. | |
10 | */ | |
11 | ||
12 | #include <linux/types.h> | |
13 | #include <linux/atomic.h> | |
14 | #include <linux/blkdev.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/list.h> | |
18 | #include <linux/mempool.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/pagemap.h> | |
21 | #include <linux/slab.h> | |
22 | #include <linux/vmalloc.h> | |
23 | #include <linux/workqueue.h> | |
24 | #include <linux/mutex.h> | |
25 | #include <linux/device-mapper.h> | |
26 | #include <linux/dm-kcopyd.h> | |
27 | ||
28 | #include "dm.h" | |
29 | ||
30 | #define SUB_JOB_SIZE 128 | |
31 | #define SPLIT_COUNT 8 | |
32 | #define MIN_JOBS 8 | |
33 | #define RESERVE_PAGES (DIV_ROUND_UP(SUB_JOB_SIZE << SECTOR_SHIFT, PAGE_SIZE)) | |
34 | ||
35 | /*----------------------------------------------------------------- | |
36 | * Each kcopyd client has its own little pool of preallocated | |
37 | * pages for kcopyd io. | |
38 | *---------------------------------------------------------------*/ | |
39 | struct dm_kcopyd_client { | |
40 | struct page_list *pages; | |
41 | unsigned nr_reserved_pages; | |
42 | unsigned nr_free_pages; | |
43 | ||
44 | struct dm_io_client *io_client; | |
45 | ||
46 | wait_queue_head_t destroyq; | |
47 | atomic_t nr_jobs; | |
48 | ||
49 | mempool_t *job_pool; | |
50 | ||
51 | struct workqueue_struct *kcopyd_wq; | |
52 | struct work_struct kcopyd_work; | |
53 | ||
54 | /* | |
55 | * We maintain three lists of jobs: | |
56 | * | |
57 | * i) jobs waiting for pages | |
58 | * ii) jobs that have pages, and are waiting for the io to be issued. | |
59 | * iii) jobs that have completed. | |
60 | * | |
61 | * All three of these are protected by job_lock. | |
62 | */ | |
63 | spinlock_t job_lock; | |
64 | struct list_head complete_jobs; | |
65 | struct list_head io_jobs; | |
66 | struct list_head pages_jobs; | |
67 | }; | |
68 | ||
69 | static struct page_list zero_page_list; | |
70 | ||
71 | static void wake(struct dm_kcopyd_client *kc) | |
72 | { | |
73 | queue_work(kc->kcopyd_wq, &kc->kcopyd_work); | |
74 | } | |
75 | ||
76 | /* | |
77 | * Obtain one page for the use of kcopyd. | |
78 | */ | |
79 | static struct page_list *alloc_pl(gfp_t gfp) | |
80 | { | |
81 | struct page_list *pl; | |
82 | ||
83 | pl = kmalloc(sizeof(*pl), gfp); | |
84 | if (!pl) | |
85 | return NULL; | |
86 | ||
87 | pl->page = alloc_page(gfp); | |
88 | if (!pl->page) { | |
89 | kfree(pl); | |
90 | return NULL; | |
91 | } | |
92 | ||
93 | return pl; | |
94 | } | |
95 | ||
96 | static void free_pl(struct page_list *pl) | |
97 | { | |
98 | __free_page(pl->page); | |
99 | kfree(pl); | |
100 | } | |
101 | ||
102 | /* | |
103 | * Add the provided pages to a client's free page list, releasing | |
104 | * back to the system any beyond the reserved_pages limit. | |
105 | */ | |
106 | static void kcopyd_put_pages(struct dm_kcopyd_client *kc, struct page_list *pl) | |
107 | { | |
108 | struct page_list *next; | |
109 | ||
110 | do { | |
111 | next = pl->next; | |
112 | ||
113 | if (kc->nr_free_pages >= kc->nr_reserved_pages) | |
114 | free_pl(pl); | |
115 | else { | |
116 | pl->next = kc->pages; | |
117 | kc->pages = pl; | |
118 | kc->nr_free_pages++; | |
119 | } | |
120 | ||
121 | pl = next; | |
122 | } while (pl); | |
123 | } | |
124 | ||
125 | static int kcopyd_get_pages(struct dm_kcopyd_client *kc, | |
126 | unsigned int nr, struct page_list **pages) | |
127 | { | |
128 | struct page_list *pl; | |
129 | ||
130 | *pages = NULL; | |
131 | ||
132 | do { | |
133 | pl = alloc_pl(__GFP_NOWARN | __GFP_NORETRY); | |
134 | if (unlikely(!pl)) { | |
135 | /* Use reserved pages */ | |
136 | pl = kc->pages; | |
137 | if (unlikely(!pl)) | |
138 | goto out_of_memory; | |
139 | kc->pages = pl->next; | |
140 | kc->nr_free_pages--; | |
141 | } | |
142 | pl->next = *pages; | |
143 | *pages = pl; | |
144 | } while (--nr); | |
145 | ||
146 | return 0; | |
147 | ||
148 | out_of_memory: | |
149 | if (*pages) | |
150 | kcopyd_put_pages(kc, *pages); | |
151 | return -ENOMEM; | |
152 | } | |
153 | ||
154 | /* | |
155 | * These three functions resize the page pool. | |
156 | */ | |
157 | static void drop_pages(struct page_list *pl) | |
158 | { | |
159 | struct page_list *next; | |
160 | ||
161 | while (pl) { | |
162 | next = pl->next; | |
163 | free_pl(pl); | |
164 | pl = next; | |
165 | } | |
166 | } | |
167 | ||
168 | /* | |
169 | * Allocate and reserve nr_pages for the use of a specific client. | |
170 | */ | |
171 | static int client_reserve_pages(struct dm_kcopyd_client *kc, unsigned nr_pages) | |
172 | { | |
173 | unsigned i; | |
174 | struct page_list *pl = NULL, *next; | |
175 | ||
176 | for (i = 0; i < nr_pages; i++) { | |
177 | next = alloc_pl(GFP_KERNEL); | |
178 | if (!next) { | |
179 | if (pl) | |
180 | drop_pages(pl); | |
181 | return -ENOMEM; | |
182 | } | |
183 | next->next = pl; | |
184 | pl = next; | |
185 | } | |
186 | ||
187 | kc->nr_reserved_pages += nr_pages; | |
188 | kcopyd_put_pages(kc, pl); | |
189 | ||
190 | return 0; | |
191 | } | |
192 | ||
193 | static void client_free_pages(struct dm_kcopyd_client *kc) | |
194 | { | |
195 | BUG_ON(kc->nr_free_pages != kc->nr_reserved_pages); | |
196 | drop_pages(kc->pages); | |
197 | kc->pages = NULL; | |
198 | kc->nr_free_pages = kc->nr_reserved_pages = 0; | |
199 | } | |
200 | ||
201 | /*----------------------------------------------------------------- | |
202 | * kcopyd_jobs need to be allocated by the *clients* of kcopyd, | |
203 | * for this reason we use a mempool to prevent the client from | |
204 | * ever having to do io (which could cause a deadlock). | |
205 | *---------------------------------------------------------------*/ | |
206 | struct kcopyd_job { | |
207 | struct dm_kcopyd_client *kc; | |
208 | struct list_head list; | |
209 | unsigned long flags; | |
210 | ||
211 | /* | |
212 | * Error state of the job. | |
213 | */ | |
214 | int read_err; | |
215 | unsigned long write_err; | |
216 | ||
217 | /* | |
218 | * Either READ or WRITE | |
219 | */ | |
220 | int rw; | |
221 | struct dm_io_region source; | |
222 | ||
223 | /* | |
224 | * The destinations for the transfer. | |
225 | */ | |
226 | unsigned int num_dests; | |
227 | struct dm_io_region dests[DM_KCOPYD_MAX_REGIONS]; | |
228 | ||
229 | struct page_list *pages; | |
230 | ||
231 | /* | |
232 | * Set this to ensure you are notified when the job has | |
233 | * completed. 'context' is for callback to use. | |
234 | */ | |
235 | dm_kcopyd_notify_fn fn; | |
236 | void *context; | |
237 | ||
238 | /* | |
239 | * These fields are only used if the job has been split | |
240 | * into more manageable parts. | |
241 | */ | |
242 | struct mutex lock; | |
243 | atomic_t sub_jobs; | |
244 | sector_t progress; | |
245 | ||
246 | struct kcopyd_job *master_job; | |
247 | }; | |
248 | ||
249 | static struct kmem_cache *_job_cache; | |
250 | ||
251 | int __init dm_kcopyd_init(void) | |
252 | { | |
253 | _job_cache = kmem_cache_create("kcopyd_job", | |
254 | sizeof(struct kcopyd_job) * (SPLIT_COUNT + 1), | |
255 | __alignof__(struct kcopyd_job), 0, NULL); | |
256 | if (!_job_cache) | |
257 | return -ENOMEM; | |
258 | ||
259 | zero_page_list.next = &zero_page_list; | |
260 | zero_page_list.page = ZERO_PAGE(0); | |
261 | ||
262 | return 0; | |
263 | } | |
264 | ||
265 | void dm_kcopyd_exit(void) | |
266 | { | |
267 | kmem_cache_destroy(_job_cache); | |
268 | _job_cache = NULL; | |
269 | } | |
270 | ||
271 | /* | |
272 | * Functions to push and pop a job onto the head of a given job | |
273 | * list. | |
274 | */ | |
275 | static struct kcopyd_job *pop(struct list_head *jobs, | |
276 | struct dm_kcopyd_client *kc) | |
277 | { | |
278 | struct kcopyd_job *job = NULL; | |
279 | unsigned long flags; | |
280 | ||
281 | spin_lock_irqsave(&kc->job_lock, flags); | |
282 | ||
283 | if (!list_empty(jobs)) { | |
284 | job = list_entry(jobs->next, struct kcopyd_job, list); | |
285 | list_del(&job->list); | |
286 | } | |
287 | spin_unlock_irqrestore(&kc->job_lock, flags); | |
288 | ||
289 | return job; | |
290 | } | |
291 | ||
292 | static void push(struct list_head *jobs, struct kcopyd_job *job) | |
293 | { | |
294 | unsigned long flags; | |
295 | struct dm_kcopyd_client *kc = job->kc; | |
296 | ||
297 | spin_lock_irqsave(&kc->job_lock, flags); | |
298 | list_add_tail(&job->list, jobs); | |
299 | spin_unlock_irqrestore(&kc->job_lock, flags); | |
300 | } | |
301 | ||
302 | ||
303 | static void push_head(struct list_head *jobs, struct kcopyd_job *job) | |
304 | { | |
305 | unsigned long flags; | |
306 | struct dm_kcopyd_client *kc = job->kc; | |
307 | ||
308 | spin_lock_irqsave(&kc->job_lock, flags); | |
309 | list_add(&job->list, jobs); | |
310 | spin_unlock_irqrestore(&kc->job_lock, flags); | |
311 | } | |
312 | ||
313 | /* | |
314 | * These three functions process 1 item from the corresponding | |
315 | * job list. | |
316 | * | |
317 | * They return: | |
318 | * < 0: error | |
319 | * 0: success | |
320 | * > 0: can't process yet. | |
321 | */ | |
322 | static int run_complete_job(struct kcopyd_job *job) | |
323 | { | |
324 | void *context = job->context; | |
325 | int read_err = job->read_err; | |
326 | unsigned long write_err = job->write_err; | |
327 | dm_kcopyd_notify_fn fn = job->fn; | |
328 | struct dm_kcopyd_client *kc = job->kc; | |
329 | ||
330 | if (job->pages && job->pages != &zero_page_list) | |
331 | kcopyd_put_pages(kc, job->pages); | |
332 | /* | |
333 | * If this is the master job, the sub jobs have already | |
334 | * completed so we can free everything. | |
335 | */ | |
336 | if (job->master_job == job) | |
337 | mempool_free(job, kc->job_pool); | |
338 | fn(read_err, write_err, context); | |
339 | ||
340 | if (atomic_dec_and_test(&kc->nr_jobs)) | |
341 | wake_up(&kc->destroyq); | |
342 | ||
343 | return 0; | |
344 | } | |
345 | ||
346 | static void complete_io(unsigned long error, void *context) | |
347 | { | |
348 | struct kcopyd_job *job = (struct kcopyd_job *) context; | |
349 | struct dm_kcopyd_client *kc = job->kc; | |
350 | ||
351 | if (error) { | |
352 | if (job->rw & WRITE) | |
353 | job->write_err |= error; | |
354 | else | |
355 | job->read_err = 1; | |
356 | ||
357 | if (!test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { | |
358 | push(&kc->complete_jobs, job); | |
359 | wake(kc); | |
360 | return; | |
361 | } | |
362 | } | |
363 | ||
364 | if (job->rw & WRITE) | |
365 | push(&kc->complete_jobs, job); | |
366 | ||
367 | else { | |
368 | job->rw = WRITE; | |
369 | push(&kc->io_jobs, job); | |
370 | } | |
371 | ||
372 | wake(kc); | |
373 | } | |
374 | ||
375 | /* | |
376 | * Request io on as many buffer heads as we can currently get for | |
377 | * a particular job. | |
378 | */ | |
379 | static int run_io_job(struct kcopyd_job *job) | |
380 | { | |
381 | int r; | |
382 | struct dm_io_request io_req = { | |
383 | .bi_rw = job->rw, | |
384 | .mem.type = DM_IO_PAGE_LIST, | |
385 | .mem.ptr.pl = job->pages, | |
386 | .mem.offset = 0, | |
387 | .notify.fn = complete_io, | |
388 | .notify.context = job, | |
389 | .client = job->kc->io_client, | |
390 | }; | |
391 | ||
392 | if (job->rw == READ) | |
393 | r = dm_io(&io_req, 1, &job->source, NULL); | |
394 | else | |
395 | r = dm_io(&io_req, job->num_dests, job->dests, NULL); | |
396 | ||
397 | return r; | |
398 | } | |
399 | ||
400 | static int run_pages_job(struct kcopyd_job *job) | |
401 | { | |
402 | int r; | |
403 | unsigned nr_pages = dm_div_up(job->dests[0].count, PAGE_SIZE >> 9); | |
404 | ||
405 | r = kcopyd_get_pages(job->kc, nr_pages, &job->pages); | |
406 | if (!r) { | |
407 | /* this job is ready for io */ | |
408 | push(&job->kc->io_jobs, job); | |
409 | return 0; | |
410 | } | |
411 | ||
412 | if (r == -ENOMEM) | |
413 | /* can't complete now */ | |
414 | return 1; | |
415 | ||
416 | return r; | |
417 | } | |
418 | ||
419 | /* | |
420 | * Run through a list for as long as possible. Returns the count | |
421 | * of successful jobs. | |
422 | */ | |
423 | static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc, | |
424 | int (*fn) (struct kcopyd_job *)) | |
425 | { | |
426 | struct kcopyd_job *job; | |
427 | int r, count = 0; | |
428 | ||
429 | while ((job = pop(jobs, kc))) { | |
430 | ||
431 | r = fn(job); | |
432 | ||
433 | if (r < 0) { | |
434 | /* error this rogue job */ | |
435 | if (job->rw & WRITE) | |
436 | job->write_err = (unsigned long) -1L; | |
437 | else | |
438 | job->read_err = 1; | |
439 | push(&kc->complete_jobs, job); | |
440 | break; | |
441 | } | |
442 | ||
443 | if (r > 0) { | |
444 | /* | |
445 | * We couldn't service this job ATM, so | |
446 | * push this job back onto the list. | |
447 | */ | |
448 | push_head(jobs, job); | |
449 | break; | |
450 | } | |
451 | ||
452 | count++; | |
453 | } | |
454 | ||
455 | return count; | |
456 | } | |
457 | ||
458 | /* | |
459 | * kcopyd does this every time it's woken up. | |
460 | */ | |
461 | static void do_work(struct work_struct *work) | |
462 | { | |
463 | struct dm_kcopyd_client *kc = container_of(work, | |
464 | struct dm_kcopyd_client, kcopyd_work); | |
465 | struct blk_plug plug; | |
466 | ||
467 | /* | |
468 | * The order that these are called is *very* important. | |
469 | * complete jobs can free some pages for pages jobs. | |
470 | * Pages jobs when successful will jump onto the io jobs | |
471 | * list. io jobs call wake when they complete and it all | |
472 | * starts again. | |
473 | */ | |
474 | blk_start_plug(&plug); | |
475 | process_jobs(&kc->complete_jobs, kc, run_complete_job); | |
476 | process_jobs(&kc->pages_jobs, kc, run_pages_job); | |
477 | process_jobs(&kc->io_jobs, kc, run_io_job); | |
478 | blk_finish_plug(&plug); | |
479 | } | |
480 | ||
481 | /* | |
482 | * If we are copying a small region we just dispatch a single job | |
483 | * to do the copy, otherwise the io has to be split up into many | |
484 | * jobs. | |
485 | */ | |
486 | static void dispatch_job(struct kcopyd_job *job) | |
487 | { | |
488 | struct dm_kcopyd_client *kc = job->kc; | |
489 | atomic_inc(&kc->nr_jobs); | |
490 | if (unlikely(!job->source.count)) | |
491 | push(&kc->complete_jobs, job); | |
492 | else if (job->pages == &zero_page_list) | |
493 | push(&kc->io_jobs, job); | |
494 | else | |
495 | push(&kc->pages_jobs, job); | |
496 | wake(kc); | |
497 | } | |
498 | ||
499 | static void segment_complete(int read_err, unsigned long write_err, | |
500 | void *context) | |
501 | { | |
502 | /* FIXME: tidy this function */ | |
503 | sector_t progress = 0; | |
504 | sector_t count = 0; | |
505 | struct kcopyd_job *sub_job = (struct kcopyd_job *) context; | |
506 | struct kcopyd_job *job = sub_job->master_job; | |
507 | struct dm_kcopyd_client *kc = job->kc; | |
508 | ||
509 | mutex_lock(&job->lock); | |
510 | ||
511 | /* update the error */ | |
512 | if (read_err) | |
513 | job->read_err = 1; | |
514 | ||
515 | if (write_err) | |
516 | job->write_err |= write_err; | |
517 | ||
518 | /* | |
519 | * Only dispatch more work if there hasn't been an error. | |
520 | */ | |
521 | if ((!job->read_err && !job->write_err) || | |
522 | test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { | |
523 | /* get the next chunk of work */ | |
524 | progress = job->progress; | |
525 | count = job->source.count - progress; | |
526 | if (count) { | |
527 | if (count > SUB_JOB_SIZE) | |
528 | count = SUB_JOB_SIZE; | |
529 | ||
530 | job->progress += count; | |
531 | } | |
532 | } | |
533 | mutex_unlock(&job->lock); | |
534 | ||
535 | if (count) { | |
536 | int i; | |
537 | ||
538 | *sub_job = *job; | |
539 | sub_job->source.sector += progress; | |
540 | sub_job->source.count = count; | |
541 | ||
542 | for (i = 0; i < job->num_dests; i++) { | |
543 | sub_job->dests[i].sector += progress; | |
544 | sub_job->dests[i].count = count; | |
545 | } | |
546 | ||
547 | sub_job->fn = segment_complete; | |
548 | sub_job->context = sub_job; | |
549 | dispatch_job(sub_job); | |
550 | ||
551 | } else if (atomic_dec_and_test(&job->sub_jobs)) { | |
552 | ||
553 | /* | |
554 | * Queue the completion callback to the kcopyd thread. | |
555 | * | |
556 | * Some callers assume that all the completions are called | |
557 | * from a single thread and don't race with each other. | |
558 | * | |
559 | * We must not call the callback directly here because this | |
560 | * code may not be executing in the thread. | |
561 | */ | |
562 | push(&kc->complete_jobs, job); | |
563 | wake(kc); | |
564 | } | |
565 | } | |
566 | ||
567 | /* | |
568 | * Create some sub jobs to share the work between them. | |
569 | */ | |
570 | static void split_job(struct kcopyd_job *master_job) | |
571 | { | |
572 | int i; | |
573 | ||
574 | atomic_inc(&master_job->kc->nr_jobs); | |
575 | ||
576 | atomic_set(&master_job->sub_jobs, SPLIT_COUNT); | |
577 | for (i = 0; i < SPLIT_COUNT; i++) { | |
578 | master_job[i + 1].master_job = master_job; | |
579 | segment_complete(0, 0u, &master_job[i + 1]); | |
580 | } | |
581 | } | |
582 | ||
583 | int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, | |
584 | unsigned int num_dests, struct dm_io_region *dests, | |
585 | unsigned int flags, dm_kcopyd_notify_fn fn, void *context) | |
586 | { | |
587 | struct kcopyd_job *job; | |
588 | int i; | |
589 | ||
590 | /* | |
591 | * Allocate an array of jobs consisting of one master job | |
592 | * followed by SPLIT_COUNT sub jobs. | |
593 | */ | |
594 | job = mempool_alloc(kc->job_pool, GFP_NOIO); | |
595 | ||
596 | /* | |
597 | * set up for the read. | |
598 | */ | |
599 | job->kc = kc; | |
600 | job->flags = flags; | |
601 | job->read_err = 0; | |
602 | job->write_err = 0; | |
603 | ||
604 | job->num_dests = num_dests; | |
605 | memcpy(&job->dests, dests, sizeof(*dests) * num_dests); | |
606 | ||
607 | if (from) { | |
608 | job->source = *from; | |
609 | job->pages = NULL; | |
610 | job->rw = READ; | |
611 | } else { | |
612 | memset(&job->source, 0, sizeof job->source); | |
613 | job->source.count = job->dests[0].count; | |
614 | job->pages = &zero_page_list; | |
615 | ||
616 | /* | |
617 | * Use WRITE SAME to optimize zeroing if all dests support it. | |
618 | */ | |
619 | job->rw = WRITE | REQ_WRITE_SAME; | |
620 | for (i = 0; i < job->num_dests; i++) | |
621 | if (!bdev_write_same(job->dests[i].bdev)) { | |
622 | job->rw = WRITE; | |
623 | break; | |
624 | } | |
625 | } | |
626 | ||
627 | job->fn = fn; | |
628 | job->context = context; | |
629 | job->master_job = job; | |
630 | ||
631 | if (job->source.count <= SUB_JOB_SIZE) | |
632 | dispatch_job(job); | |
633 | else { | |
634 | mutex_init(&job->lock); | |
635 | job->progress = 0; | |
636 | split_job(job); | |
637 | } | |
638 | ||
639 | return 0; | |
640 | } | |
641 | EXPORT_SYMBOL(dm_kcopyd_copy); | |
642 | ||
643 | int dm_kcopyd_zero(struct dm_kcopyd_client *kc, | |
644 | unsigned num_dests, struct dm_io_region *dests, | |
645 | unsigned flags, dm_kcopyd_notify_fn fn, void *context) | |
646 | { | |
647 | return dm_kcopyd_copy(kc, NULL, num_dests, dests, flags, fn, context); | |
648 | } | |
649 | EXPORT_SYMBOL(dm_kcopyd_zero); | |
650 | ||
651 | void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc, | |
652 | dm_kcopyd_notify_fn fn, void *context) | |
653 | { | |
654 | struct kcopyd_job *job; | |
655 | ||
656 | job = mempool_alloc(kc->job_pool, GFP_NOIO); | |
657 | ||
658 | memset(job, 0, sizeof(struct kcopyd_job)); | |
659 | job->kc = kc; | |
660 | job->fn = fn; | |
661 | job->context = context; | |
662 | job->master_job = job; | |
663 | ||
664 | atomic_inc(&kc->nr_jobs); | |
665 | ||
666 | return job; | |
667 | } | |
668 | EXPORT_SYMBOL(dm_kcopyd_prepare_callback); | |
669 | ||
670 | void dm_kcopyd_do_callback(void *j, int read_err, unsigned long write_err) | |
671 | { | |
672 | struct kcopyd_job *job = j; | |
673 | struct dm_kcopyd_client *kc = job->kc; | |
674 | ||
675 | job->read_err = read_err; | |
676 | job->write_err = write_err; | |
677 | ||
678 | push(&kc->complete_jobs, job); | |
679 | wake(kc); | |
680 | } | |
681 | EXPORT_SYMBOL(dm_kcopyd_do_callback); | |
682 | ||
683 | /* | |
684 | * Cancels a kcopyd job, eg. someone might be deactivating a | |
685 | * mirror. | |
686 | */ | |
687 | #if 0 | |
688 | int kcopyd_cancel(struct kcopyd_job *job, int block) | |
689 | { | |
690 | /* FIXME: finish */ | |
691 | return -1; | |
692 | } | |
693 | #endif /* 0 */ | |
694 | ||
695 | /*----------------------------------------------------------------- | |
696 | * Client setup | |
697 | *---------------------------------------------------------------*/ | |
698 | struct dm_kcopyd_client *dm_kcopyd_client_create(void) | |
699 | { | |
700 | int r = -ENOMEM; | |
701 | struct dm_kcopyd_client *kc; | |
702 | ||
703 | kc = kmalloc(sizeof(*kc), GFP_KERNEL); | |
704 | if (!kc) | |
705 | return ERR_PTR(-ENOMEM); | |
706 | ||
707 | spin_lock_init(&kc->job_lock); | |
708 | INIT_LIST_HEAD(&kc->complete_jobs); | |
709 | INIT_LIST_HEAD(&kc->io_jobs); | |
710 | INIT_LIST_HEAD(&kc->pages_jobs); | |
711 | ||
712 | kc->job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache); | |
713 | if (!kc->job_pool) | |
714 | goto bad_slab; | |
715 | ||
716 | INIT_WORK(&kc->kcopyd_work, do_work); | |
717 | kc->kcopyd_wq = alloc_workqueue("kcopyd", | |
718 | WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0); | |
719 | if (!kc->kcopyd_wq) | |
720 | goto bad_workqueue; | |
721 | ||
722 | kc->pages = NULL; | |
723 | kc->nr_reserved_pages = kc->nr_free_pages = 0; | |
724 | r = client_reserve_pages(kc, RESERVE_PAGES); | |
725 | if (r) | |
726 | goto bad_client_pages; | |
727 | ||
728 | kc->io_client = dm_io_client_create(); | |
729 | if (IS_ERR(kc->io_client)) { | |
730 | r = PTR_ERR(kc->io_client); | |
731 | goto bad_io_client; | |
732 | } | |
733 | ||
734 | init_waitqueue_head(&kc->destroyq); | |
735 | atomic_set(&kc->nr_jobs, 0); | |
736 | ||
737 | return kc; | |
738 | ||
739 | bad_io_client: | |
740 | client_free_pages(kc); | |
741 | bad_client_pages: | |
742 | destroy_workqueue(kc->kcopyd_wq); | |
743 | bad_workqueue: | |
744 | mempool_destroy(kc->job_pool); | |
745 | bad_slab: | |
746 | kfree(kc); | |
747 | ||
748 | return ERR_PTR(r); | |
749 | } | |
750 | EXPORT_SYMBOL(dm_kcopyd_client_create); | |
751 | ||
752 | void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc) | |
753 | { | |
754 | /* Wait for completion of all jobs submitted by this client. */ | |
755 | wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs)); | |
756 | ||
757 | BUG_ON(!list_empty(&kc->complete_jobs)); | |
758 | BUG_ON(!list_empty(&kc->io_jobs)); | |
759 | BUG_ON(!list_empty(&kc->pages_jobs)); | |
760 | destroy_workqueue(kc->kcopyd_wq); | |
761 | dm_io_client_destroy(kc->io_client); | |
762 | client_free_pages(kc); | |
763 | mempool_destroy(kc->job_pool); | |
764 | kfree(kc); | |
765 | } | |
766 | EXPORT_SYMBOL(dm_kcopyd_client_destroy); |