Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2002 Sistina Software (UK) Limited. | |
373a392b | 3 | * Copyright (C) 2006 Red Hat GmbH |
1da177e4 LT |
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 | ||
eb69aca5 | 12 | #include <linux/types.h> |
1da177e4 | 13 | #include <asm/atomic.h> |
1da177e4 | 14 | #include <linux/blkdev.h> |
1da177e4 LT |
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> | |
48c9c27b | 24 | #include <linux/mutex.h> |
1da177e4 LT |
25 | |
26 | #include "kcopyd.h" | |
22a1ceb1 | 27 | #include "dm.h" |
1da177e4 | 28 | |
1da177e4 LT |
29 | /*----------------------------------------------------------------- |
30 | * Each kcopyd client has its own little pool of preallocated | |
31 | * pages for kcopyd io. | |
32 | *---------------------------------------------------------------*/ | |
eb69aca5 | 33 | struct dm_kcopyd_client { |
1da177e4 LT |
34 | struct list_head list; |
35 | ||
36 | spinlock_t lock; | |
37 | struct page_list *pages; | |
38 | unsigned int nr_pages; | |
39 | unsigned int nr_free_pages; | |
138728dc | 40 | |
373a392b MB |
41 | struct dm_io_client *io_client; |
42 | ||
138728dc AK |
43 | wait_queue_head_t destroyq; |
44 | atomic_t nr_jobs; | |
8c0cbc2f MP |
45 | |
46 | struct workqueue_struct *kcopyd_wq; | |
47 | struct work_struct kcopyd_work; | |
48 | ||
49 | /* | |
50 | * We maintain three lists of jobs: | |
51 | * | |
52 | * i) jobs waiting for pages | |
53 | * ii) jobs that have pages, and are waiting for the io to be issued. | |
54 | * iii) jobs that have completed. | |
55 | * | |
56 | * All three of these are protected by job_lock. | |
57 | */ | |
58 | spinlock_t job_lock; | |
59 | struct list_head complete_jobs; | |
60 | struct list_head io_jobs; | |
61 | struct list_head pages_jobs; | |
1da177e4 LT |
62 | }; |
63 | ||
8c0cbc2f MP |
64 | static void wake(struct dm_kcopyd_client *kc) |
65 | { | |
66 | queue_work(kc->kcopyd_wq, &kc->kcopyd_work); | |
67 | } | |
68 | ||
1da177e4 LT |
69 | static struct page_list *alloc_pl(void) |
70 | { | |
71 | struct page_list *pl; | |
72 | ||
73 | pl = kmalloc(sizeof(*pl), GFP_KERNEL); | |
74 | if (!pl) | |
75 | return NULL; | |
76 | ||
77 | pl->page = alloc_page(GFP_KERNEL); | |
78 | if (!pl->page) { | |
79 | kfree(pl); | |
80 | return NULL; | |
81 | } | |
82 | ||
83 | return pl; | |
84 | } | |
85 | ||
86 | static void free_pl(struct page_list *pl) | |
87 | { | |
88 | __free_page(pl->page); | |
89 | kfree(pl); | |
90 | } | |
91 | ||
eb69aca5 | 92 | static int kcopyd_get_pages(struct dm_kcopyd_client *kc, |
1da177e4 LT |
93 | unsigned int nr, struct page_list **pages) |
94 | { | |
95 | struct page_list *pl; | |
96 | ||
97 | spin_lock(&kc->lock); | |
98 | if (kc->nr_free_pages < nr) { | |
99 | spin_unlock(&kc->lock); | |
100 | return -ENOMEM; | |
101 | } | |
102 | ||
103 | kc->nr_free_pages -= nr; | |
104 | for (*pages = pl = kc->pages; --nr; pl = pl->next) | |
105 | ; | |
106 | ||
107 | kc->pages = pl->next; | |
108 | pl->next = NULL; | |
109 | ||
110 | spin_unlock(&kc->lock); | |
111 | ||
112 | return 0; | |
113 | } | |
114 | ||
eb69aca5 | 115 | static void kcopyd_put_pages(struct dm_kcopyd_client *kc, struct page_list *pl) |
1da177e4 LT |
116 | { |
117 | struct page_list *cursor; | |
118 | ||
119 | spin_lock(&kc->lock); | |
120 | for (cursor = pl; cursor->next; cursor = cursor->next) | |
121 | kc->nr_free_pages++; | |
122 | ||
123 | kc->nr_free_pages++; | |
124 | cursor->next = kc->pages; | |
125 | kc->pages = pl; | |
126 | spin_unlock(&kc->lock); | |
127 | } | |
128 | ||
129 | /* | |
130 | * These three functions resize the page pool. | |
131 | */ | |
132 | static void drop_pages(struct page_list *pl) | |
133 | { | |
134 | struct page_list *next; | |
135 | ||
136 | while (pl) { | |
137 | next = pl->next; | |
138 | free_pl(pl); | |
139 | pl = next; | |
140 | } | |
141 | } | |
142 | ||
eb69aca5 | 143 | static int client_alloc_pages(struct dm_kcopyd_client *kc, unsigned int nr) |
1da177e4 LT |
144 | { |
145 | unsigned int i; | |
146 | struct page_list *pl = NULL, *next; | |
147 | ||
148 | for (i = 0; i < nr; i++) { | |
149 | next = alloc_pl(); | |
150 | if (!next) { | |
151 | if (pl) | |
152 | drop_pages(pl); | |
153 | return -ENOMEM; | |
154 | } | |
155 | next->next = pl; | |
156 | pl = next; | |
157 | } | |
158 | ||
159 | kcopyd_put_pages(kc, pl); | |
160 | kc->nr_pages += nr; | |
161 | return 0; | |
162 | } | |
163 | ||
eb69aca5 | 164 | static void client_free_pages(struct dm_kcopyd_client *kc) |
1da177e4 LT |
165 | { |
166 | BUG_ON(kc->nr_free_pages != kc->nr_pages); | |
167 | drop_pages(kc->pages); | |
168 | kc->pages = NULL; | |
169 | kc->nr_free_pages = kc->nr_pages = 0; | |
170 | } | |
171 | ||
172 | /*----------------------------------------------------------------- | |
173 | * kcopyd_jobs need to be allocated by the *clients* of kcopyd, | |
174 | * for this reason we use a mempool to prevent the client from | |
175 | * ever having to do io (which could cause a deadlock). | |
176 | *---------------------------------------------------------------*/ | |
177 | struct kcopyd_job { | |
eb69aca5 | 178 | struct dm_kcopyd_client *kc; |
1da177e4 LT |
179 | struct list_head list; |
180 | unsigned long flags; | |
181 | ||
182 | /* | |
183 | * Error state of the job. | |
184 | */ | |
185 | int read_err; | |
4cdc1d1f | 186 | unsigned long write_err; |
1da177e4 LT |
187 | |
188 | /* | |
189 | * Either READ or WRITE | |
190 | */ | |
191 | int rw; | |
22a1ceb1 | 192 | struct dm_io_region source; |
1da177e4 LT |
193 | |
194 | /* | |
195 | * The destinations for the transfer. | |
196 | */ | |
197 | unsigned int num_dests; | |
eb69aca5 | 198 | struct dm_io_region dests[DM_KCOPYD_MAX_REGIONS]; |
1da177e4 LT |
199 | |
200 | sector_t offset; | |
201 | unsigned int nr_pages; | |
202 | struct page_list *pages; | |
203 | ||
204 | /* | |
205 | * Set this to ensure you are notified when the job has | |
206 | * completed. 'context' is for callback to use. | |
207 | */ | |
eb69aca5 | 208 | dm_kcopyd_notify_fn fn; |
1da177e4 LT |
209 | void *context; |
210 | ||
211 | /* | |
212 | * These fields are only used if the job has been split | |
213 | * into more manageable parts. | |
214 | */ | |
def5b5b2 | 215 | struct mutex lock; |
1da177e4 LT |
216 | atomic_t sub_jobs; |
217 | sector_t progress; | |
218 | }; | |
219 | ||
220 | /* FIXME: this should scale with the number of pages */ | |
221 | #define MIN_JOBS 512 | |
222 | ||
e18b890b | 223 | static struct kmem_cache *_job_cache; |
1da177e4 LT |
224 | static mempool_t *_job_pool; |
225 | ||
1da177e4 LT |
226 | static int jobs_init(void) |
227 | { | |
028867ac | 228 | _job_cache = KMEM_CACHE(kcopyd_job, 0); |
1da177e4 LT |
229 | if (!_job_cache) |
230 | return -ENOMEM; | |
231 | ||
93d2341c | 232 | _job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache); |
1da177e4 LT |
233 | if (!_job_pool) { |
234 | kmem_cache_destroy(_job_cache); | |
235 | return -ENOMEM; | |
236 | } | |
237 | ||
238 | return 0; | |
239 | } | |
240 | ||
241 | static void jobs_exit(void) | |
242 | { | |
1da177e4 LT |
243 | mempool_destroy(_job_pool); |
244 | kmem_cache_destroy(_job_cache); | |
245 | _job_pool = NULL; | |
246 | _job_cache = NULL; | |
247 | } | |
248 | ||
249 | /* | |
250 | * Functions to push and pop a job onto the head of a given job | |
251 | * list. | |
252 | */ | |
8c0cbc2f MP |
253 | static struct kcopyd_job *pop(struct list_head *jobs, |
254 | struct dm_kcopyd_client *kc) | |
1da177e4 LT |
255 | { |
256 | struct kcopyd_job *job = NULL; | |
257 | unsigned long flags; | |
258 | ||
8c0cbc2f | 259 | spin_lock_irqsave(&kc->job_lock, flags); |
1da177e4 LT |
260 | |
261 | if (!list_empty(jobs)) { | |
262 | job = list_entry(jobs->next, struct kcopyd_job, list); | |
263 | list_del(&job->list); | |
264 | } | |
8c0cbc2f | 265 | spin_unlock_irqrestore(&kc->job_lock, flags); |
1da177e4 LT |
266 | |
267 | return job; | |
268 | } | |
269 | ||
028867ac | 270 | static void push(struct list_head *jobs, struct kcopyd_job *job) |
1da177e4 LT |
271 | { |
272 | unsigned long flags; | |
8c0cbc2f | 273 | struct dm_kcopyd_client *kc = job->kc; |
1da177e4 | 274 | |
8c0cbc2f | 275 | spin_lock_irqsave(&kc->job_lock, flags); |
1da177e4 | 276 | list_add_tail(&job->list, jobs); |
8c0cbc2f | 277 | spin_unlock_irqrestore(&kc->job_lock, flags); |
1da177e4 LT |
278 | } |
279 | ||
280 | /* | |
281 | * These three functions process 1 item from the corresponding | |
282 | * job list. | |
283 | * | |
284 | * They return: | |
285 | * < 0: error | |
286 | * 0: success | |
287 | * > 0: can't process yet. | |
288 | */ | |
289 | static int run_complete_job(struct kcopyd_job *job) | |
290 | { | |
291 | void *context = job->context; | |
292 | int read_err = job->read_err; | |
4cdc1d1f | 293 | unsigned long write_err = job->write_err; |
eb69aca5 HM |
294 | dm_kcopyd_notify_fn fn = job->fn; |
295 | struct dm_kcopyd_client *kc = job->kc; | |
1da177e4 | 296 | |
138728dc | 297 | kcopyd_put_pages(kc, job->pages); |
1da177e4 LT |
298 | mempool_free(job, _job_pool); |
299 | fn(read_err, write_err, context); | |
138728dc AK |
300 | |
301 | if (atomic_dec_and_test(&kc->nr_jobs)) | |
302 | wake_up(&kc->destroyq); | |
303 | ||
1da177e4 LT |
304 | return 0; |
305 | } | |
306 | ||
307 | static void complete_io(unsigned long error, void *context) | |
308 | { | |
309 | struct kcopyd_job *job = (struct kcopyd_job *) context; | |
8c0cbc2f | 310 | struct dm_kcopyd_client *kc = job->kc; |
1da177e4 LT |
311 | |
312 | if (error) { | |
313 | if (job->rw == WRITE) | |
ce503f59 | 314 | job->write_err |= error; |
1da177e4 LT |
315 | else |
316 | job->read_err = 1; | |
317 | ||
eb69aca5 | 318 | if (!test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { |
8c0cbc2f MP |
319 | push(&kc->complete_jobs, job); |
320 | wake(kc); | |
1da177e4 LT |
321 | return; |
322 | } | |
323 | } | |
324 | ||
325 | if (job->rw == WRITE) | |
8c0cbc2f | 326 | push(&kc->complete_jobs, job); |
1da177e4 LT |
327 | |
328 | else { | |
329 | job->rw = WRITE; | |
8c0cbc2f | 330 | push(&kc->io_jobs, job); |
1da177e4 LT |
331 | } |
332 | ||
8c0cbc2f | 333 | wake(kc); |
1da177e4 LT |
334 | } |
335 | ||
336 | /* | |
337 | * Request io on as many buffer heads as we can currently get for | |
338 | * a particular job. | |
339 | */ | |
340 | static int run_io_job(struct kcopyd_job *job) | |
341 | { | |
342 | int r; | |
373a392b MB |
343 | struct dm_io_request io_req = { |
344 | .bi_rw = job->rw, | |
345 | .mem.type = DM_IO_PAGE_LIST, | |
346 | .mem.ptr.pl = job->pages, | |
347 | .mem.offset = job->offset, | |
348 | .notify.fn = complete_io, | |
349 | .notify.context = job, | |
350 | .client = job->kc->io_client, | |
351 | }; | |
1da177e4 LT |
352 | |
353 | if (job->rw == READ) | |
373a392b | 354 | r = dm_io(&io_req, 1, &job->source, NULL); |
1da177e4 | 355 | else |
373a392b | 356 | r = dm_io(&io_req, job->num_dests, job->dests, NULL); |
1da177e4 LT |
357 | |
358 | return r; | |
359 | } | |
360 | ||
361 | static int run_pages_job(struct kcopyd_job *job) | |
362 | { | |
363 | int r; | |
364 | ||
365 | job->nr_pages = dm_div_up(job->dests[0].count + job->offset, | |
366 | PAGE_SIZE >> 9); | |
367 | r = kcopyd_get_pages(job->kc, job->nr_pages, &job->pages); | |
368 | if (!r) { | |
369 | /* this job is ready for io */ | |
8c0cbc2f | 370 | push(&job->kc->io_jobs, job); |
1da177e4 LT |
371 | return 0; |
372 | } | |
373 | ||
374 | if (r == -ENOMEM) | |
375 | /* can't complete now */ | |
376 | return 1; | |
377 | ||
378 | return r; | |
379 | } | |
380 | ||
381 | /* | |
382 | * Run through a list for as long as possible. Returns the count | |
383 | * of successful jobs. | |
384 | */ | |
8c0cbc2f MP |
385 | static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc, |
386 | int (*fn) (struct kcopyd_job *)) | |
1da177e4 LT |
387 | { |
388 | struct kcopyd_job *job; | |
389 | int r, count = 0; | |
390 | ||
8c0cbc2f | 391 | while ((job = pop(jobs, kc))) { |
1da177e4 LT |
392 | |
393 | r = fn(job); | |
394 | ||
395 | if (r < 0) { | |
396 | /* error this rogue job */ | |
397 | if (job->rw == WRITE) | |
4cdc1d1f | 398 | job->write_err = (unsigned long) -1L; |
1da177e4 LT |
399 | else |
400 | job->read_err = 1; | |
8c0cbc2f | 401 | push(&kc->complete_jobs, job); |
1da177e4 LT |
402 | break; |
403 | } | |
404 | ||
405 | if (r > 0) { | |
406 | /* | |
407 | * We couldn't service this job ATM, so | |
408 | * push this job back onto the list. | |
409 | */ | |
410 | push(jobs, job); | |
411 | break; | |
412 | } | |
413 | ||
414 | count++; | |
415 | } | |
416 | ||
417 | return count; | |
418 | } | |
419 | ||
420 | /* | |
421 | * kcopyd does this every time it's woken up. | |
422 | */ | |
8c0cbc2f | 423 | static void do_work(struct work_struct *work) |
1da177e4 | 424 | { |
8c0cbc2f MP |
425 | struct dm_kcopyd_client *kc = container_of(work, |
426 | struct dm_kcopyd_client, kcopyd_work); | |
427 | ||
1da177e4 LT |
428 | /* |
429 | * The order that these are called is *very* important. | |
430 | * complete jobs can free some pages for pages jobs. | |
431 | * Pages jobs when successful will jump onto the io jobs | |
432 | * list. io jobs call wake when they complete and it all | |
433 | * starts again. | |
434 | */ | |
8c0cbc2f MP |
435 | process_jobs(&kc->complete_jobs, kc, run_complete_job); |
436 | process_jobs(&kc->pages_jobs, kc, run_pages_job); | |
437 | process_jobs(&kc->io_jobs, kc, run_io_job); | |
1da177e4 LT |
438 | } |
439 | ||
440 | /* | |
441 | * If we are copying a small region we just dispatch a single job | |
442 | * to do the copy, otherwise the io has to be split up into many | |
443 | * jobs. | |
444 | */ | |
445 | static void dispatch_job(struct kcopyd_job *job) | |
446 | { | |
8c0cbc2f MP |
447 | struct dm_kcopyd_client *kc = job->kc; |
448 | atomic_inc(&kc->nr_jobs); | |
449 | push(&kc->pages_jobs, job); | |
450 | wake(kc); | |
1da177e4 LT |
451 | } |
452 | ||
453 | #define SUB_JOB_SIZE 128 | |
4cdc1d1f AK |
454 | static void segment_complete(int read_err, unsigned long write_err, |
455 | void *context) | |
1da177e4 LT |
456 | { |
457 | /* FIXME: tidy this function */ | |
458 | sector_t progress = 0; | |
459 | sector_t count = 0; | |
460 | struct kcopyd_job *job = (struct kcopyd_job *) context; | |
461 | ||
def5b5b2 | 462 | mutex_lock(&job->lock); |
1da177e4 LT |
463 | |
464 | /* update the error */ | |
465 | if (read_err) | |
466 | job->read_err = 1; | |
467 | ||
468 | if (write_err) | |
ce503f59 | 469 | job->write_err |= write_err; |
1da177e4 LT |
470 | |
471 | /* | |
472 | * Only dispatch more work if there hasn't been an error. | |
473 | */ | |
474 | if ((!job->read_err && !job->write_err) || | |
eb69aca5 | 475 | test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { |
1da177e4 LT |
476 | /* get the next chunk of work */ |
477 | progress = job->progress; | |
478 | count = job->source.count - progress; | |
479 | if (count) { | |
480 | if (count > SUB_JOB_SIZE) | |
481 | count = SUB_JOB_SIZE; | |
482 | ||
483 | job->progress += count; | |
484 | } | |
485 | } | |
def5b5b2 | 486 | mutex_unlock(&job->lock); |
1da177e4 LT |
487 | |
488 | if (count) { | |
489 | int i; | |
490 | struct kcopyd_job *sub_job = mempool_alloc(_job_pool, GFP_NOIO); | |
491 | ||
492 | *sub_job = *job; | |
493 | sub_job->source.sector += progress; | |
494 | sub_job->source.count = count; | |
495 | ||
496 | for (i = 0; i < job->num_dests; i++) { | |
497 | sub_job->dests[i].sector += progress; | |
498 | sub_job->dests[i].count = count; | |
499 | } | |
500 | ||
501 | sub_job->fn = segment_complete; | |
502 | sub_job->context = job; | |
503 | dispatch_job(sub_job); | |
504 | ||
505 | } else if (atomic_dec_and_test(&job->sub_jobs)) { | |
506 | ||
507 | /* | |
508 | * To avoid a race we must keep the job around | |
509 | * until after the notify function has completed. | |
510 | * Otherwise the client may try and stop the job | |
511 | * after we've completed. | |
512 | */ | |
513 | job->fn(read_err, write_err, job->context); | |
514 | mempool_free(job, _job_pool); | |
515 | } | |
516 | } | |
517 | ||
518 | /* | |
519 | * Create some little jobs that will do the move between | |
520 | * them. | |
521 | */ | |
522 | #define SPLIT_COUNT 8 | |
523 | static void split_job(struct kcopyd_job *job) | |
524 | { | |
525 | int i; | |
526 | ||
527 | atomic_set(&job->sub_jobs, SPLIT_COUNT); | |
528 | for (i = 0; i < SPLIT_COUNT; i++) | |
529 | segment_complete(0, 0u, job); | |
530 | } | |
531 | ||
eb69aca5 HM |
532 | int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, |
533 | unsigned int num_dests, struct dm_io_region *dests, | |
534 | unsigned int flags, dm_kcopyd_notify_fn fn, void *context) | |
1da177e4 LT |
535 | { |
536 | struct kcopyd_job *job; | |
537 | ||
538 | /* | |
539 | * Allocate a new job. | |
540 | */ | |
541 | job = mempool_alloc(_job_pool, GFP_NOIO); | |
542 | ||
543 | /* | |
544 | * set up for the read. | |
545 | */ | |
546 | job->kc = kc; | |
547 | job->flags = flags; | |
548 | job->read_err = 0; | |
549 | job->write_err = 0; | |
550 | job->rw = READ; | |
551 | ||
552 | job->source = *from; | |
553 | ||
554 | job->num_dests = num_dests; | |
555 | memcpy(&job->dests, dests, sizeof(*dests) * num_dests); | |
556 | ||
557 | job->offset = 0; | |
558 | job->nr_pages = 0; | |
559 | job->pages = NULL; | |
560 | ||
561 | job->fn = fn; | |
562 | job->context = context; | |
563 | ||
564 | if (job->source.count < SUB_JOB_SIZE) | |
565 | dispatch_job(job); | |
566 | ||
567 | else { | |
def5b5b2 | 568 | mutex_init(&job->lock); |
1da177e4 LT |
569 | job->progress = 0; |
570 | split_job(job); | |
571 | } | |
572 | ||
573 | return 0; | |
574 | } | |
eb69aca5 | 575 | EXPORT_SYMBOL(dm_kcopyd_copy); |
1da177e4 LT |
576 | |
577 | /* | |
578 | * Cancels a kcopyd job, eg. someone might be deactivating a | |
579 | * mirror. | |
580 | */ | |
0b56306e | 581 | #if 0 |
1da177e4 LT |
582 | int kcopyd_cancel(struct kcopyd_job *job, int block) |
583 | { | |
584 | /* FIXME: finish */ | |
585 | return -1; | |
586 | } | |
0b56306e | 587 | #endif /* 0 */ |
1da177e4 LT |
588 | |
589 | /*----------------------------------------------------------------- | |
590 | * Unit setup | |
591 | *---------------------------------------------------------------*/ | |
48c9c27b | 592 | static DEFINE_MUTEX(_client_lock); |
1da177e4 LT |
593 | static LIST_HEAD(_clients); |
594 | ||
eb69aca5 | 595 | static void client_add(struct dm_kcopyd_client *kc) |
1da177e4 | 596 | { |
48c9c27b | 597 | mutex_lock(&_client_lock); |
1da177e4 | 598 | list_add(&kc->list, &_clients); |
48c9c27b | 599 | mutex_unlock(&_client_lock); |
1da177e4 LT |
600 | } |
601 | ||
eb69aca5 | 602 | static void client_del(struct dm_kcopyd_client *kc) |
1da177e4 | 603 | { |
48c9c27b | 604 | mutex_lock(&_client_lock); |
1da177e4 | 605 | list_del(&kc->list); |
48c9c27b | 606 | mutex_unlock(&_client_lock); |
1da177e4 LT |
607 | } |
608 | ||
14cc3e2b | 609 | static DEFINE_MUTEX(kcopyd_init_lock); |
1da177e4 LT |
610 | static int kcopyd_clients = 0; |
611 | ||
612 | static int kcopyd_init(void) | |
613 | { | |
614 | int r; | |
615 | ||
14cc3e2b | 616 | mutex_lock(&kcopyd_init_lock); |
1da177e4 LT |
617 | |
618 | if (kcopyd_clients) { | |
619 | /* Already initialized. */ | |
620 | kcopyd_clients++; | |
14cc3e2b | 621 | mutex_unlock(&kcopyd_init_lock); |
1da177e4 LT |
622 | return 0; |
623 | } | |
624 | ||
625 | r = jobs_init(); | |
626 | if (r) { | |
14cc3e2b | 627 | mutex_unlock(&kcopyd_init_lock); |
1da177e4 LT |
628 | return r; |
629 | } | |
630 | ||
1da177e4 | 631 | kcopyd_clients++; |
14cc3e2b | 632 | mutex_unlock(&kcopyd_init_lock); |
1da177e4 LT |
633 | return 0; |
634 | } | |
635 | ||
636 | static void kcopyd_exit(void) | |
637 | { | |
14cc3e2b | 638 | mutex_lock(&kcopyd_init_lock); |
1da177e4 LT |
639 | kcopyd_clients--; |
640 | if (!kcopyd_clients) { | |
641 | jobs_exit(); | |
1da177e4 | 642 | } |
14cc3e2b | 643 | mutex_unlock(&kcopyd_init_lock); |
1da177e4 LT |
644 | } |
645 | ||
eb69aca5 HM |
646 | int dm_kcopyd_client_create(unsigned int nr_pages, |
647 | struct dm_kcopyd_client **result) | |
1da177e4 LT |
648 | { |
649 | int r = 0; | |
eb69aca5 | 650 | struct dm_kcopyd_client *kc; |
1da177e4 LT |
651 | |
652 | r = kcopyd_init(); | |
653 | if (r) | |
654 | return r; | |
655 | ||
656 | kc = kmalloc(sizeof(*kc), GFP_KERNEL); | |
657 | if (!kc) { | |
8c0cbc2f | 658 | r = -ENOMEM; |
1da177e4 | 659 | kcopyd_exit(); |
8c0cbc2f | 660 | return r; |
1da177e4 LT |
661 | } |
662 | ||
663 | spin_lock_init(&kc->lock); | |
8c0cbc2f MP |
664 | spin_lock_init(&kc->job_lock); |
665 | INIT_LIST_HEAD(&kc->complete_jobs); | |
666 | INIT_LIST_HEAD(&kc->io_jobs); | |
667 | INIT_LIST_HEAD(&kc->pages_jobs); | |
668 | ||
669 | INIT_WORK(&kc->kcopyd_work, do_work); | |
670 | kc->kcopyd_wq = create_singlethread_workqueue("kcopyd"); | |
671 | if (!kc->kcopyd_wq) { | |
672 | r = -ENOMEM; | |
673 | kfree(kc); | |
674 | kcopyd_exit(); | |
675 | return r; | |
676 | } | |
677 | ||
1da177e4 LT |
678 | kc->pages = NULL; |
679 | kc->nr_pages = kc->nr_free_pages = 0; | |
680 | r = client_alloc_pages(kc, nr_pages); | |
681 | if (r) { | |
8c0cbc2f | 682 | destroy_workqueue(kc->kcopyd_wq); |
1da177e4 LT |
683 | kfree(kc); |
684 | kcopyd_exit(); | |
685 | return r; | |
686 | } | |
687 | ||
373a392b MB |
688 | kc->io_client = dm_io_client_create(nr_pages); |
689 | if (IS_ERR(kc->io_client)) { | |
690 | r = PTR_ERR(kc->io_client); | |
1da177e4 | 691 | client_free_pages(kc); |
8c0cbc2f | 692 | destroy_workqueue(kc->kcopyd_wq); |
1da177e4 LT |
693 | kfree(kc); |
694 | kcopyd_exit(); | |
695 | return r; | |
696 | } | |
697 | ||
138728dc AK |
698 | init_waitqueue_head(&kc->destroyq); |
699 | atomic_set(&kc->nr_jobs, 0); | |
700 | ||
1da177e4 LT |
701 | client_add(kc); |
702 | *result = kc; | |
703 | return 0; | |
704 | } | |
eb69aca5 | 705 | EXPORT_SYMBOL(dm_kcopyd_client_create); |
1da177e4 | 706 | |
eb69aca5 | 707 | void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc) |
1da177e4 | 708 | { |
138728dc AK |
709 | /* Wait for completion of all jobs submitted by this client. */ |
710 | wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs)); | |
711 | ||
8c0cbc2f MP |
712 | BUG_ON(!list_empty(&kc->complete_jobs)); |
713 | BUG_ON(!list_empty(&kc->io_jobs)); | |
714 | BUG_ON(!list_empty(&kc->pages_jobs)); | |
715 | destroy_workqueue(kc->kcopyd_wq); | |
373a392b | 716 | dm_io_client_destroy(kc->io_client); |
1da177e4 LT |
717 | client_free_pages(kc); |
718 | client_del(kc); | |
719 | kfree(kc); | |
720 | kcopyd_exit(); | |
721 | } | |
eb69aca5 | 722 | EXPORT_SYMBOL(dm_kcopyd_client_destroy); |