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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 | ||
715b49ef | 12 | #include <asm/types.h> |
1da177e4 LT |
13 | #include <asm/atomic.h> |
14 | ||
15 | #include <linux/blkdev.h> | |
1da177e4 LT |
16 | #include <linux/fs.h> |
17 | #include <linux/init.h> | |
18 | #include <linux/list.h> | |
19 | #include <linux/mempool.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/pagemap.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/vmalloc.h> | |
24 | #include <linux/workqueue.h> | |
48c9c27b | 25 | #include <linux/mutex.h> |
1da177e4 LT |
26 | |
27 | #include "kcopyd.h" | |
28 | ||
29 | static struct workqueue_struct *_kcopyd_wq; | |
30 | static struct work_struct _kcopyd_work; | |
31 | ||
028867ac | 32 | static void wake(void) |
1da177e4 LT |
33 | { |
34 | queue_work(_kcopyd_wq, &_kcopyd_work); | |
35 | } | |
36 | ||
37 | /*----------------------------------------------------------------- | |
38 | * Each kcopyd client has its own little pool of preallocated | |
39 | * pages for kcopyd io. | |
40 | *---------------------------------------------------------------*/ | |
41 | struct kcopyd_client { | |
42 | struct list_head list; | |
43 | ||
44 | spinlock_t lock; | |
45 | struct page_list *pages; | |
46 | unsigned int nr_pages; | |
47 | unsigned int nr_free_pages; | |
138728dc | 48 | |
373a392b MB |
49 | struct dm_io_client *io_client; |
50 | ||
138728dc AK |
51 | wait_queue_head_t destroyq; |
52 | atomic_t nr_jobs; | |
1da177e4 LT |
53 | }; |
54 | ||
55 | static struct page_list *alloc_pl(void) | |
56 | { | |
57 | struct page_list *pl; | |
58 | ||
59 | pl = kmalloc(sizeof(*pl), GFP_KERNEL); | |
60 | if (!pl) | |
61 | return NULL; | |
62 | ||
63 | pl->page = alloc_page(GFP_KERNEL); | |
64 | if (!pl->page) { | |
65 | kfree(pl); | |
66 | return NULL; | |
67 | } | |
68 | ||
69 | return pl; | |
70 | } | |
71 | ||
72 | static void free_pl(struct page_list *pl) | |
73 | { | |
74 | __free_page(pl->page); | |
75 | kfree(pl); | |
76 | } | |
77 | ||
78 | static int kcopyd_get_pages(struct kcopyd_client *kc, | |
79 | unsigned int nr, struct page_list **pages) | |
80 | { | |
81 | struct page_list *pl; | |
82 | ||
83 | spin_lock(&kc->lock); | |
84 | if (kc->nr_free_pages < nr) { | |
85 | spin_unlock(&kc->lock); | |
86 | return -ENOMEM; | |
87 | } | |
88 | ||
89 | kc->nr_free_pages -= nr; | |
90 | for (*pages = pl = kc->pages; --nr; pl = pl->next) | |
91 | ; | |
92 | ||
93 | kc->pages = pl->next; | |
94 | pl->next = NULL; | |
95 | ||
96 | spin_unlock(&kc->lock); | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
101 | static void kcopyd_put_pages(struct kcopyd_client *kc, struct page_list *pl) | |
102 | { | |
103 | struct page_list *cursor; | |
104 | ||
105 | spin_lock(&kc->lock); | |
106 | for (cursor = pl; cursor->next; cursor = cursor->next) | |
107 | kc->nr_free_pages++; | |
108 | ||
109 | kc->nr_free_pages++; | |
110 | cursor->next = kc->pages; | |
111 | kc->pages = pl; | |
112 | spin_unlock(&kc->lock); | |
113 | } | |
114 | ||
115 | /* | |
116 | * These three functions resize the page pool. | |
117 | */ | |
118 | static void drop_pages(struct page_list *pl) | |
119 | { | |
120 | struct page_list *next; | |
121 | ||
122 | while (pl) { | |
123 | next = pl->next; | |
124 | free_pl(pl); | |
125 | pl = next; | |
126 | } | |
127 | } | |
128 | ||
129 | static int client_alloc_pages(struct kcopyd_client *kc, unsigned int nr) | |
130 | { | |
131 | unsigned int i; | |
132 | struct page_list *pl = NULL, *next; | |
133 | ||
134 | for (i = 0; i < nr; i++) { | |
135 | next = alloc_pl(); | |
136 | if (!next) { | |
137 | if (pl) | |
138 | drop_pages(pl); | |
139 | return -ENOMEM; | |
140 | } | |
141 | next->next = pl; | |
142 | pl = next; | |
143 | } | |
144 | ||
145 | kcopyd_put_pages(kc, pl); | |
146 | kc->nr_pages += nr; | |
147 | return 0; | |
148 | } | |
149 | ||
150 | static void client_free_pages(struct kcopyd_client *kc) | |
151 | { | |
152 | BUG_ON(kc->nr_free_pages != kc->nr_pages); | |
153 | drop_pages(kc->pages); | |
154 | kc->pages = NULL; | |
155 | kc->nr_free_pages = kc->nr_pages = 0; | |
156 | } | |
157 | ||
158 | /*----------------------------------------------------------------- | |
159 | * kcopyd_jobs need to be allocated by the *clients* of kcopyd, | |
160 | * for this reason we use a mempool to prevent the client from | |
161 | * ever having to do io (which could cause a deadlock). | |
162 | *---------------------------------------------------------------*/ | |
163 | struct kcopyd_job { | |
164 | struct kcopyd_client *kc; | |
165 | struct list_head list; | |
166 | unsigned long flags; | |
167 | ||
168 | /* | |
169 | * Error state of the job. | |
170 | */ | |
171 | int read_err; | |
4cdc1d1f | 172 | unsigned long write_err; |
1da177e4 LT |
173 | |
174 | /* | |
175 | * Either READ or WRITE | |
176 | */ | |
177 | int rw; | |
178 | struct io_region source; | |
179 | ||
180 | /* | |
181 | * The destinations for the transfer. | |
182 | */ | |
183 | unsigned int num_dests; | |
184 | struct io_region dests[KCOPYD_MAX_REGIONS]; | |
185 | ||
186 | sector_t offset; | |
187 | unsigned int nr_pages; | |
188 | struct page_list *pages; | |
189 | ||
190 | /* | |
191 | * Set this to ensure you are notified when the job has | |
192 | * completed. 'context' is for callback to use. | |
193 | */ | |
194 | kcopyd_notify_fn fn; | |
195 | void *context; | |
196 | ||
197 | /* | |
198 | * These fields are only used if the job has been split | |
199 | * into more manageable parts. | |
200 | */ | |
def5b5b2 | 201 | struct mutex lock; |
1da177e4 LT |
202 | atomic_t sub_jobs; |
203 | sector_t progress; | |
204 | }; | |
205 | ||
206 | /* FIXME: this should scale with the number of pages */ | |
207 | #define MIN_JOBS 512 | |
208 | ||
e18b890b | 209 | static struct kmem_cache *_job_cache; |
1da177e4 LT |
210 | static mempool_t *_job_pool; |
211 | ||
212 | /* | |
213 | * We maintain three lists of jobs: | |
214 | * | |
215 | * i) jobs waiting for pages | |
216 | * ii) jobs that have pages, and are waiting for the io to be issued. | |
217 | * iii) jobs that have completed. | |
218 | * | |
219 | * All three of these are protected by job_lock. | |
220 | */ | |
221 | static DEFINE_SPINLOCK(_job_lock); | |
222 | ||
223 | static LIST_HEAD(_complete_jobs); | |
224 | static LIST_HEAD(_io_jobs); | |
225 | static LIST_HEAD(_pages_jobs); | |
226 | ||
227 | static int jobs_init(void) | |
228 | { | |
028867ac | 229 | _job_cache = KMEM_CACHE(kcopyd_job, 0); |
1da177e4 LT |
230 | if (!_job_cache) |
231 | return -ENOMEM; | |
232 | ||
93d2341c | 233 | _job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache); |
1da177e4 LT |
234 | if (!_job_pool) { |
235 | kmem_cache_destroy(_job_cache); | |
236 | return -ENOMEM; | |
237 | } | |
238 | ||
239 | return 0; | |
240 | } | |
241 | ||
242 | static void jobs_exit(void) | |
243 | { | |
244 | BUG_ON(!list_empty(&_complete_jobs)); | |
245 | BUG_ON(!list_empty(&_io_jobs)); | |
246 | BUG_ON(!list_empty(&_pages_jobs)); | |
247 | ||
248 | mempool_destroy(_job_pool); | |
249 | kmem_cache_destroy(_job_cache); | |
250 | _job_pool = NULL; | |
251 | _job_cache = NULL; | |
252 | } | |
253 | ||
254 | /* | |
255 | * Functions to push and pop a job onto the head of a given job | |
256 | * list. | |
257 | */ | |
028867ac | 258 | static struct kcopyd_job *pop(struct list_head *jobs) |
1da177e4 LT |
259 | { |
260 | struct kcopyd_job *job = NULL; | |
261 | unsigned long flags; | |
262 | ||
263 | spin_lock_irqsave(&_job_lock, flags); | |
264 | ||
265 | if (!list_empty(jobs)) { | |
266 | job = list_entry(jobs->next, struct kcopyd_job, list); | |
267 | list_del(&job->list); | |
268 | } | |
269 | spin_unlock_irqrestore(&_job_lock, flags); | |
270 | ||
271 | return job; | |
272 | } | |
273 | ||
028867ac | 274 | static void push(struct list_head *jobs, struct kcopyd_job *job) |
1da177e4 LT |
275 | { |
276 | unsigned long flags; | |
277 | ||
278 | spin_lock_irqsave(&_job_lock, flags); | |
279 | list_add_tail(&job->list, jobs); | |
280 | spin_unlock_irqrestore(&_job_lock, flags); | |
281 | } | |
282 | ||
283 | /* | |
284 | * These three functions process 1 item from the corresponding | |
285 | * job list. | |
286 | * | |
287 | * They return: | |
288 | * < 0: error | |
289 | * 0: success | |
290 | * > 0: can't process yet. | |
291 | */ | |
292 | static int run_complete_job(struct kcopyd_job *job) | |
293 | { | |
294 | void *context = job->context; | |
295 | int read_err = job->read_err; | |
4cdc1d1f | 296 | unsigned long write_err = job->write_err; |
1da177e4 | 297 | kcopyd_notify_fn fn = job->fn; |
138728dc | 298 | struct kcopyd_client *kc = job->kc; |
1da177e4 | 299 | |
138728dc | 300 | kcopyd_put_pages(kc, job->pages); |
1da177e4 LT |
301 | mempool_free(job, _job_pool); |
302 | fn(read_err, write_err, context); | |
138728dc AK |
303 | |
304 | if (atomic_dec_and_test(&kc->nr_jobs)) | |
305 | wake_up(&kc->destroyq); | |
306 | ||
1da177e4 LT |
307 | return 0; |
308 | } | |
309 | ||
310 | static void complete_io(unsigned long error, void *context) | |
311 | { | |
312 | struct kcopyd_job *job = (struct kcopyd_job *) context; | |
313 | ||
314 | if (error) { | |
315 | if (job->rw == WRITE) | |
ce503f59 | 316 | job->write_err |= error; |
1da177e4 LT |
317 | else |
318 | job->read_err = 1; | |
319 | ||
320 | if (!test_bit(KCOPYD_IGNORE_ERROR, &job->flags)) { | |
321 | push(&_complete_jobs, job); | |
322 | wake(); | |
323 | return; | |
324 | } | |
325 | } | |
326 | ||
327 | if (job->rw == WRITE) | |
328 | push(&_complete_jobs, job); | |
329 | ||
330 | else { | |
331 | job->rw = WRITE; | |
332 | push(&_io_jobs, job); | |
333 | } | |
334 | ||
335 | wake(); | |
336 | } | |
337 | ||
338 | /* | |
339 | * Request io on as many buffer heads as we can currently get for | |
340 | * a particular job. | |
341 | */ | |
342 | static int run_io_job(struct kcopyd_job *job) | |
343 | { | |
344 | int r; | |
373a392b MB |
345 | struct dm_io_request io_req = { |
346 | .bi_rw = job->rw, | |
347 | .mem.type = DM_IO_PAGE_LIST, | |
348 | .mem.ptr.pl = job->pages, | |
349 | .mem.offset = job->offset, | |
350 | .notify.fn = complete_io, | |
351 | .notify.context = job, | |
352 | .client = job->kc->io_client, | |
353 | }; | |
1da177e4 LT |
354 | |
355 | if (job->rw == READ) | |
373a392b | 356 | r = dm_io(&io_req, 1, &job->source, NULL); |
1da177e4 | 357 | else |
373a392b | 358 | r = dm_io(&io_req, job->num_dests, job->dests, NULL); |
1da177e4 LT |
359 | |
360 | return r; | |
361 | } | |
362 | ||
363 | static int run_pages_job(struct kcopyd_job *job) | |
364 | { | |
365 | int r; | |
366 | ||
367 | job->nr_pages = dm_div_up(job->dests[0].count + job->offset, | |
368 | PAGE_SIZE >> 9); | |
369 | r = kcopyd_get_pages(job->kc, job->nr_pages, &job->pages); | |
370 | if (!r) { | |
371 | /* this job is ready for io */ | |
372 | push(&_io_jobs, job); | |
373 | return 0; | |
374 | } | |
375 | ||
376 | if (r == -ENOMEM) | |
377 | /* can't complete now */ | |
378 | return 1; | |
379 | ||
380 | return r; | |
381 | } | |
382 | ||
383 | /* | |
384 | * Run through a list for as long as possible. Returns the count | |
385 | * of successful jobs. | |
386 | */ | |
387 | static int process_jobs(struct list_head *jobs, int (*fn) (struct kcopyd_job *)) | |
388 | { | |
389 | struct kcopyd_job *job; | |
390 | int r, count = 0; | |
391 | ||
392 | while ((job = pop(jobs))) { | |
393 | ||
394 | r = fn(job); | |
395 | ||
396 | if (r < 0) { | |
397 | /* error this rogue job */ | |
398 | if (job->rw == WRITE) | |
4cdc1d1f | 399 | job->write_err = (unsigned long) -1L; |
1da177e4 LT |
400 | else |
401 | job->read_err = 1; | |
402 | push(&_complete_jobs, job); | |
403 | break; | |
404 | } | |
405 | ||
406 | if (r > 0) { | |
407 | /* | |
408 | * We couldn't service this job ATM, so | |
409 | * push this job back onto the list. | |
410 | */ | |
411 | push(jobs, job); | |
412 | break; | |
413 | } | |
414 | ||
415 | count++; | |
416 | } | |
417 | ||
418 | return count; | |
419 | } | |
420 | ||
421 | /* | |
422 | * kcopyd does this every time it's woken up. | |
423 | */ | |
c4028958 | 424 | static void do_work(struct work_struct *ignored) |
1da177e4 LT |
425 | { |
426 | /* | |
427 | * The order that these are called is *very* important. | |
428 | * complete jobs can free some pages for pages jobs. | |
429 | * Pages jobs when successful will jump onto the io jobs | |
430 | * list. io jobs call wake when they complete and it all | |
431 | * starts again. | |
432 | */ | |
433 | process_jobs(&_complete_jobs, run_complete_job); | |
434 | process_jobs(&_pages_jobs, run_pages_job); | |
435 | process_jobs(&_io_jobs, run_io_job); | |
436 | } | |
437 | ||
438 | /* | |
439 | * If we are copying a small region we just dispatch a single job | |
440 | * to do the copy, otherwise the io has to be split up into many | |
441 | * jobs. | |
442 | */ | |
443 | static void dispatch_job(struct kcopyd_job *job) | |
444 | { | |
138728dc | 445 | atomic_inc(&job->kc->nr_jobs); |
1da177e4 LT |
446 | push(&_pages_jobs, job); |
447 | wake(); | |
448 | } | |
449 | ||
450 | #define SUB_JOB_SIZE 128 | |
4cdc1d1f AK |
451 | static void segment_complete(int read_err, unsigned long write_err, |
452 | void *context) | |
1da177e4 LT |
453 | { |
454 | /* FIXME: tidy this function */ | |
455 | sector_t progress = 0; | |
456 | sector_t count = 0; | |
457 | struct kcopyd_job *job = (struct kcopyd_job *) context; | |
458 | ||
def5b5b2 | 459 | mutex_lock(&job->lock); |
1da177e4 LT |
460 | |
461 | /* update the error */ | |
462 | if (read_err) | |
463 | job->read_err = 1; | |
464 | ||
465 | if (write_err) | |
ce503f59 | 466 | job->write_err |= write_err; |
1da177e4 LT |
467 | |
468 | /* | |
469 | * Only dispatch more work if there hasn't been an error. | |
470 | */ | |
471 | if ((!job->read_err && !job->write_err) || | |
472 | test_bit(KCOPYD_IGNORE_ERROR, &job->flags)) { | |
473 | /* get the next chunk of work */ | |
474 | progress = job->progress; | |
475 | count = job->source.count - progress; | |
476 | if (count) { | |
477 | if (count > SUB_JOB_SIZE) | |
478 | count = SUB_JOB_SIZE; | |
479 | ||
480 | job->progress += count; | |
481 | } | |
482 | } | |
def5b5b2 | 483 | mutex_unlock(&job->lock); |
1da177e4 LT |
484 | |
485 | if (count) { | |
486 | int i; | |
487 | struct kcopyd_job *sub_job = mempool_alloc(_job_pool, GFP_NOIO); | |
488 | ||
489 | *sub_job = *job; | |
490 | sub_job->source.sector += progress; | |
491 | sub_job->source.count = count; | |
492 | ||
493 | for (i = 0; i < job->num_dests; i++) { | |
494 | sub_job->dests[i].sector += progress; | |
495 | sub_job->dests[i].count = count; | |
496 | } | |
497 | ||
498 | sub_job->fn = segment_complete; | |
499 | sub_job->context = job; | |
500 | dispatch_job(sub_job); | |
501 | ||
502 | } else if (atomic_dec_and_test(&job->sub_jobs)) { | |
503 | ||
504 | /* | |
505 | * To avoid a race we must keep the job around | |
506 | * until after the notify function has completed. | |
507 | * Otherwise the client may try and stop the job | |
508 | * after we've completed. | |
509 | */ | |
510 | job->fn(read_err, write_err, job->context); | |
511 | mempool_free(job, _job_pool); | |
512 | } | |
513 | } | |
514 | ||
515 | /* | |
516 | * Create some little jobs that will do the move between | |
517 | * them. | |
518 | */ | |
519 | #define SPLIT_COUNT 8 | |
520 | static void split_job(struct kcopyd_job *job) | |
521 | { | |
522 | int i; | |
523 | ||
524 | atomic_set(&job->sub_jobs, SPLIT_COUNT); | |
525 | for (i = 0; i < SPLIT_COUNT; i++) | |
526 | segment_complete(0, 0u, job); | |
527 | } | |
528 | ||
529 | int kcopyd_copy(struct kcopyd_client *kc, struct io_region *from, | |
530 | unsigned int num_dests, struct io_region *dests, | |
531 | unsigned int flags, kcopyd_notify_fn fn, void *context) | |
532 | { | |
533 | struct kcopyd_job *job; | |
534 | ||
535 | /* | |
536 | * Allocate a new job. | |
537 | */ | |
538 | job = mempool_alloc(_job_pool, GFP_NOIO); | |
539 | ||
540 | /* | |
541 | * set up for the read. | |
542 | */ | |
543 | job->kc = kc; | |
544 | job->flags = flags; | |
545 | job->read_err = 0; | |
546 | job->write_err = 0; | |
547 | job->rw = READ; | |
548 | ||
549 | job->source = *from; | |
550 | ||
551 | job->num_dests = num_dests; | |
552 | memcpy(&job->dests, dests, sizeof(*dests) * num_dests); | |
553 | ||
554 | job->offset = 0; | |
555 | job->nr_pages = 0; | |
556 | job->pages = NULL; | |
557 | ||
558 | job->fn = fn; | |
559 | job->context = context; | |
560 | ||
561 | if (job->source.count < SUB_JOB_SIZE) | |
562 | dispatch_job(job); | |
563 | ||
564 | else { | |
def5b5b2 | 565 | mutex_init(&job->lock); |
1da177e4 LT |
566 | job->progress = 0; |
567 | split_job(job); | |
568 | } | |
569 | ||
570 | return 0; | |
571 | } | |
572 | ||
573 | /* | |
574 | * Cancels a kcopyd job, eg. someone might be deactivating a | |
575 | * mirror. | |
576 | */ | |
0b56306e | 577 | #if 0 |
1da177e4 LT |
578 | int kcopyd_cancel(struct kcopyd_job *job, int block) |
579 | { | |
580 | /* FIXME: finish */ | |
581 | return -1; | |
582 | } | |
0b56306e | 583 | #endif /* 0 */ |
1da177e4 LT |
584 | |
585 | /*----------------------------------------------------------------- | |
586 | * Unit setup | |
587 | *---------------------------------------------------------------*/ | |
48c9c27b | 588 | static DEFINE_MUTEX(_client_lock); |
1da177e4 LT |
589 | static LIST_HEAD(_clients); |
590 | ||
591 | static void client_add(struct kcopyd_client *kc) | |
592 | { | |
48c9c27b | 593 | mutex_lock(&_client_lock); |
1da177e4 | 594 | list_add(&kc->list, &_clients); |
48c9c27b | 595 | mutex_unlock(&_client_lock); |
1da177e4 LT |
596 | } |
597 | ||
598 | static void client_del(struct kcopyd_client *kc) | |
599 | { | |
48c9c27b | 600 | mutex_lock(&_client_lock); |
1da177e4 | 601 | list_del(&kc->list); |
48c9c27b | 602 | mutex_unlock(&_client_lock); |
1da177e4 LT |
603 | } |
604 | ||
14cc3e2b | 605 | static DEFINE_MUTEX(kcopyd_init_lock); |
1da177e4 LT |
606 | static int kcopyd_clients = 0; |
607 | ||
608 | static int kcopyd_init(void) | |
609 | { | |
610 | int r; | |
611 | ||
14cc3e2b | 612 | mutex_lock(&kcopyd_init_lock); |
1da177e4 LT |
613 | |
614 | if (kcopyd_clients) { | |
615 | /* Already initialized. */ | |
616 | kcopyd_clients++; | |
14cc3e2b | 617 | mutex_unlock(&kcopyd_init_lock); |
1da177e4 LT |
618 | return 0; |
619 | } | |
620 | ||
621 | r = jobs_init(); | |
622 | if (r) { | |
14cc3e2b | 623 | mutex_unlock(&kcopyd_init_lock); |
1da177e4 LT |
624 | return r; |
625 | } | |
626 | ||
627 | _kcopyd_wq = create_singlethread_workqueue("kcopyd"); | |
628 | if (!_kcopyd_wq) { | |
629 | jobs_exit(); | |
14cc3e2b | 630 | mutex_unlock(&kcopyd_init_lock); |
1da177e4 LT |
631 | return -ENOMEM; |
632 | } | |
633 | ||
634 | kcopyd_clients++; | |
c4028958 | 635 | INIT_WORK(&_kcopyd_work, do_work); |
14cc3e2b | 636 | mutex_unlock(&kcopyd_init_lock); |
1da177e4 LT |
637 | return 0; |
638 | } | |
639 | ||
640 | static void kcopyd_exit(void) | |
641 | { | |
14cc3e2b | 642 | mutex_lock(&kcopyd_init_lock); |
1da177e4 LT |
643 | kcopyd_clients--; |
644 | if (!kcopyd_clients) { | |
645 | jobs_exit(); | |
646 | destroy_workqueue(_kcopyd_wq); | |
647 | _kcopyd_wq = NULL; | |
648 | } | |
14cc3e2b | 649 | mutex_unlock(&kcopyd_init_lock); |
1da177e4 LT |
650 | } |
651 | ||
652 | int kcopyd_client_create(unsigned int nr_pages, struct kcopyd_client **result) | |
653 | { | |
654 | int r = 0; | |
655 | struct kcopyd_client *kc; | |
656 | ||
657 | r = kcopyd_init(); | |
658 | if (r) | |
659 | return r; | |
660 | ||
661 | kc = kmalloc(sizeof(*kc), GFP_KERNEL); | |
662 | if (!kc) { | |
663 | kcopyd_exit(); | |
664 | return -ENOMEM; | |
665 | } | |
666 | ||
667 | spin_lock_init(&kc->lock); | |
668 | kc->pages = NULL; | |
669 | kc->nr_pages = kc->nr_free_pages = 0; | |
670 | r = client_alloc_pages(kc, nr_pages); | |
671 | if (r) { | |
672 | kfree(kc); | |
673 | kcopyd_exit(); | |
674 | return r; | |
675 | } | |
676 | ||
373a392b MB |
677 | kc->io_client = dm_io_client_create(nr_pages); |
678 | if (IS_ERR(kc->io_client)) { | |
679 | r = PTR_ERR(kc->io_client); | |
1da177e4 LT |
680 | client_free_pages(kc); |
681 | kfree(kc); | |
682 | kcopyd_exit(); | |
683 | return r; | |
684 | } | |
685 | ||
138728dc AK |
686 | init_waitqueue_head(&kc->destroyq); |
687 | atomic_set(&kc->nr_jobs, 0); | |
688 | ||
1da177e4 LT |
689 | client_add(kc); |
690 | *result = kc; | |
691 | return 0; | |
692 | } | |
693 | ||
694 | void kcopyd_client_destroy(struct kcopyd_client *kc) | |
695 | { | |
138728dc AK |
696 | /* Wait for completion of all jobs submitted by this client. */ |
697 | wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs)); | |
698 | ||
373a392b | 699 | dm_io_client_destroy(kc->io_client); |
1da177e4 LT |
700 | client_free_pages(kc); |
701 | client_del(kc); | |
702 | kfree(kc); | |
703 | kcopyd_exit(); | |
704 | } | |
705 | ||
706 | EXPORT_SYMBOL(kcopyd_client_create); | |
707 | EXPORT_SYMBOL(kcopyd_client_destroy); | |
708 | EXPORT_SYMBOL(kcopyd_copy); |