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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> |
586e80e6 | 25 | #include <linux/device-mapper.h> |
a765e20e | 26 | #include <linux/dm-kcopyd.h> |
1da177e4 | 27 | |
22a1ceb1 | 28 | #include "dm.h" |
1da177e4 | 29 | |
c6ea41fb MP |
30 | #define SUB_JOB_SIZE 128 |
31 | #define SPLIT_COUNT 8 | |
32 | #define MIN_JOBS 8 | |
33 | ||
1da177e4 LT |
34 | /*----------------------------------------------------------------- |
35 | * Each kcopyd client has its own little pool of preallocated | |
36 | * pages for kcopyd io. | |
37 | *---------------------------------------------------------------*/ | |
eb69aca5 | 38 | struct dm_kcopyd_client { |
1da177e4 | 39 | struct page_list *pages; |
d0471458 MP |
40 | unsigned nr_reserved_pages; |
41 | unsigned nr_free_pages; | |
138728dc | 42 | |
373a392b MB |
43 | struct dm_io_client *io_client; |
44 | ||
138728dc AK |
45 | wait_queue_head_t destroyq; |
46 | atomic_t nr_jobs; | |
8c0cbc2f | 47 | |
08d8757a MP |
48 | mempool_t *job_pool; |
49 | ||
8c0cbc2f MP |
50 | struct workqueue_struct *kcopyd_wq; |
51 | struct work_struct kcopyd_work; | |
52 | ||
53 | /* | |
54 | * We maintain three lists of jobs: | |
55 | * | |
56 | * i) jobs waiting for pages | |
57 | * ii) jobs that have pages, and are waiting for the io to be issued. | |
58 | * iii) jobs that have completed. | |
59 | * | |
60 | * All three of these are protected by job_lock. | |
61 | */ | |
62 | spinlock_t job_lock; | |
63 | struct list_head complete_jobs; | |
64 | struct list_head io_jobs; | |
65 | struct list_head pages_jobs; | |
1da177e4 LT |
66 | }; |
67 | ||
8c0cbc2f MP |
68 | static void wake(struct dm_kcopyd_client *kc) |
69 | { | |
70 | queue_work(kc->kcopyd_wq, &kc->kcopyd_work); | |
71 | } | |
72 | ||
d0471458 MP |
73 | /* |
74 | * Obtain one page for the use of kcopyd. | |
75 | */ | |
f99b55ee | 76 | static struct page_list *alloc_pl(gfp_t gfp) |
1da177e4 LT |
77 | { |
78 | struct page_list *pl; | |
79 | ||
f99b55ee | 80 | pl = kmalloc(sizeof(*pl), gfp); |
1da177e4 LT |
81 | if (!pl) |
82 | return NULL; | |
83 | ||
f99b55ee | 84 | pl->page = alloc_page(gfp); |
1da177e4 LT |
85 | if (!pl->page) { |
86 | kfree(pl); | |
87 | return NULL; | |
88 | } | |
89 | ||
90 | return pl; | |
91 | } | |
92 | ||
93 | static void free_pl(struct page_list *pl) | |
94 | { | |
95 | __free_page(pl->page); | |
96 | kfree(pl); | |
97 | } | |
98 | ||
d0471458 MP |
99 | /* |
100 | * Add the provided pages to a client's free page list, releasing | |
101 | * back to the system any beyond the reserved_pages limit. | |
102 | */ | |
103 | static void kcopyd_put_pages(struct dm_kcopyd_client *kc, struct page_list *pl) | |
1da177e4 | 104 | { |
d0471458 | 105 | struct page_list *next; |
1da177e4 | 106 | |
d0471458 MP |
107 | do { |
108 | next = pl->next; | |
1da177e4 | 109 | |
d0471458 MP |
110 | if (kc->nr_free_pages >= kc->nr_reserved_pages) |
111 | free_pl(pl); | |
112 | else { | |
113 | pl->next = kc->pages; | |
114 | kc->pages = pl; | |
115 | kc->nr_free_pages++; | |
116 | } | |
1da177e4 | 117 | |
d0471458 MP |
118 | pl = next; |
119 | } while (pl); | |
1da177e4 LT |
120 | } |
121 | ||
d0471458 MP |
122 | static int kcopyd_get_pages(struct dm_kcopyd_client *kc, |
123 | unsigned int nr, struct page_list **pages) | |
1da177e4 | 124 | { |
d0471458 | 125 | struct page_list *pl; |
1da177e4 | 126 | |
d0471458 MP |
127 | *pages = NULL; |
128 | ||
129 | do { | |
130 | pl = alloc_pl(__GFP_NOWARN | __GFP_NORETRY); | |
131 | if (unlikely(!pl)) { | |
132 | /* Use reserved pages */ | |
133 | pl = kc->pages; | |
134 | if (unlikely(!pl)) | |
135 | goto out_of_memory; | |
136 | kc->pages = pl->next; | |
137 | kc->nr_free_pages--; | |
138 | } | |
139 | pl->next = *pages; | |
140 | *pages = pl; | |
141 | } while (--nr); | |
142 | ||
143 | return 0; | |
1da177e4 | 144 | |
d0471458 MP |
145 | out_of_memory: |
146 | if (*pages) | |
147 | kcopyd_put_pages(kc, *pages); | |
148 | return -ENOMEM; | |
1da177e4 LT |
149 | } |
150 | ||
151 | /* | |
152 | * These three functions resize the page pool. | |
153 | */ | |
154 | static void drop_pages(struct page_list *pl) | |
155 | { | |
156 | struct page_list *next; | |
157 | ||
158 | while (pl) { | |
159 | next = pl->next; | |
160 | free_pl(pl); | |
161 | pl = next; | |
162 | } | |
163 | } | |
164 | ||
d0471458 MP |
165 | /* |
166 | * Allocate and reserve nr_pages for the use of a specific client. | |
167 | */ | |
168 | static int client_reserve_pages(struct dm_kcopyd_client *kc, unsigned nr_pages) | |
1da177e4 | 169 | { |
d0471458 | 170 | unsigned i; |
1da177e4 LT |
171 | struct page_list *pl = NULL, *next; |
172 | ||
d0471458 | 173 | for (i = 0; i < nr_pages; i++) { |
f99b55ee | 174 | next = alloc_pl(GFP_KERNEL); |
1da177e4 LT |
175 | if (!next) { |
176 | if (pl) | |
177 | drop_pages(pl); | |
178 | return -ENOMEM; | |
179 | } | |
180 | next->next = pl; | |
181 | pl = next; | |
182 | } | |
183 | ||
d0471458 | 184 | kc->nr_reserved_pages += nr_pages; |
1da177e4 | 185 | kcopyd_put_pages(kc, pl); |
d0471458 | 186 | |
1da177e4 LT |
187 | return 0; |
188 | } | |
189 | ||
eb69aca5 | 190 | static void client_free_pages(struct dm_kcopyd_client *kc) |
1da177e4 | 191 | { |
d0471458 | 192 | BUG_ON(kc->nr_free_pages != kc->nr_reserved_pages); |
1da177e4 LT |
193 | drop_pages(kc->pages); |
194 | kc->pages = NULL; | |
d0471458 | 195 | kc->nr_free_pages = kc->nr_reserved_pages = 0; |
1da177e4 LT |
196 | } |
197 | ||
198 | /*----------------------------------------------------------------- | |
199 | * kcopyd_jobs need to be allocated by the *clients* of kcopyd, | |
200 | * for this reason we use a mempool to prevent the client from | |
201 | * ever having to do io (which could cause a deadlock). | |
202 | *---------------------------------------------------------------*/ | |
203 | struct kcopyd_job { | |
eb69aca5 | 204 | struct dm_kcopyd_client *kc; |
1da177e4 LT |
205 | struct list_head list; |
206 | unsigned long flags; | |
207 | ||
208 | /* | |
209 | * Error state of the job. | |
210 | */ | |
211 | int read_err; | |
4cdc1d1f | 212 | unsigned long write_err; |
1da177e4 LT |
213 | |
214 | /* | |
215 | * Either READ or WRITE | |
216 | */ | |
217 | int rw; | |
22a1ceb1 | 218 | struct dm_io_region source; |
1da177e4 LT |
219 | |
220 | /* | |
221 | * The destinations for the transfer. | |
222 | */ | |
223 | unsigned int num_dests; | |
eb69aca5 | 224 | struct dm_io_region dests[DM_KCOPYD_MAX_REGIONS]; |
1da177e4 LT |
225 | |
226 | sector_t offset; | |
227 | unsigned int nr_pages; | |
228 | struct page_list *pages; | |
229 | ||
230 | /* | |
231 | * Set this to ensure you are notified when the job has | |
232 | * completed. 'context' is for callback to use. | |
233 | */ | |
eb69aca5 | 234 | dm_kcopyd_notify_fn fn; |
1da177e4 LT |
235 | void *context; |
236 | ||
237 | /* | |
238 | * These fields are only used if the job has been split | |
239 | * into more manageable parts. | |
240 | */ | |
def5b5b2 | 241 | struct mutex lock; |
1da177e4 LT |
242 | atomic_t sub_jobs; |
243 | sector_t progress; | |
1da177e4 | 244 | |
c6ea41fb MP |
245 | struct kcopyd_job *master_job; |
246 | }; | |
1da177e4 | 247 | |
e18b890b | 248 | static struct kmem_cache *_job_cache; |
1da177e4 | 249 | |
945fa4d2 | 250 | int __init dm_kcopyd_init(void) |
1da177e4 | 251 | { |
c6ea41fb MP |
252 | _job_cache = kmem_cache_create("kcopyd_job", |
253 | sizeof(struct kcopyd_job) * (SPLIT_COUNT + 1), | |
254 | __alignof__(struct kcopyd_job), 0, NULL); | |
1da177e4 LT |
255 | if (!_job_cache) |
256 | return -ENOMEM; | |
257 | ||
1da177e4 LT |
258 | return 0; |
259 | } | |
260 | ||
945fa4d2 | 261 | void dm_kcopyd_exit(void) |
1da177e4 | 262 | { |
1da177e4 | 263 | kmem_cache_destroy(_job_cache); |
1da177e4 LT |
264 | _job_cache = NULL; |
265 | } | |
266 | ||
267 | /* | |
268 | * Functions to push and pop a job onto the head of a given job | |
269 | * list. | |
270 | */ | |
8c0cbc2f MP |
271 | static struct kcopyd_job *pop(struct list_head *jobs, |
272 | struct dm_kcopyd_client *kc) | |
1da177e4 LT |
273 | { |
274 | struct kcopyd_job *job = NULL; | |
275 | unsigned long flags; | |
276 | ||
8c0cbc2f | 277 | spin_lock_irqsave(&kc->job_lock, flags); |
1da177e4 LT |
278 | |
279 | if (!list_empty(jobs)) { | |
280 | job = list_entry(jobs->next, struct kcopyd_job, list); | |
281 | list_del(&job->list); | |
282 | } | |
8c0cbc2f | 283 | spin_unlock_irqrestore(&kc->job_lock, flags); |
1da177e4 LT |
284 | |
285 | return job; | |
286 | } | |
287 | ||
028867ac | 288 | static void push(struct list_head *jobs, struct kcopyd_job *job) |
1da177e4 LT |
289 | { |
290 | unsigned long flags; | |
8c0cbc2f | 291 | struct dm_kcopyd_client *kc = job->kc; |
1da177e4 | 292 | |
8c0cbc2f | 293 | spin_lock_irqsave(&kc->job_lock, flags); |
1da177e4 | 294 | list_add_tail(&job->list, jobs); |
8c0cbc2f | 295 | spin_unlock_irqrestore(&kc->job_lock, flags); |
1da177e4 LT |
296 | } |
297 | ||
b673c3a8 KI |
298 | |
299 | static void push_head(struct list_head *jobs, struct kcopyd_job *job) | |
300 | { | |
301 | unsigned long flags; | |
302 | struct dm_kcopyd_client *kc = job->kc; | |
303 | ||
304 | spin_lock_irqsave(&kc->job_lock, flags); | |
305 | list_add(&job->list, jobs); | |
306 | spin_unlock_irqrestore(&kc->job_lock, flags); | |
307 | } | |
308 | ||
1da177e4 LT |
309 | /* |
310 | * These three functions process 1 item from the corresponding | |
311 | * job list. | |
312 | * | |
313 | * They return: | |
314 | * < 0: error | |
315 | * 0: success | |
316 | * > 0: can't process yet. | |
317 | */ | |
318 | static int run_complete_job(struct kcopyd_job *job) | |
319 | { | |
320 | void *context = job->context; | |
321 | int read_err = job->read_err; | |
4cdc1d1f | 322 | unsigned long write_err = job->write_err; |
eb69aca5 HM |
323 | dm_kcopyd_notify_fn fn = job->fn; |
324 | struct dm_kcopyd_client *kc = job->kc; | |
1da177e4 | 325 | |
73830857 MP |
326 | if (job->pages) |
327 | kcopyd_put_pages(kc, job->pages); | |
c6ea41fb MP |
328 | /* |
329 | * If this is the master job, the sub jobs have already | |
330 | * completed so we can free everything. | |
331 | */ | |
332 | if (job->master_job == job) | |
333 | mempool_free(job, kc->job_pool); | |
1da177e4 | 334 | fn(read_err, write_err, context); |
138728dc AK |
335 | |
336 | if (atomic_dec_and_test(&kc->nr_jobs)) | |
337 | wake_up(&kc->destroyq); | |
338 | ||
1da177e4 LT |
339 | return 0; |
340 | } | |
341 | ||
342 | static void complete_io(unsigned long error, void *context) | |
343 | { | |
344 | struct kcopyd_job *job = (struct kcopyd_job *) context; | |
8c0cbc2f | 345 | struct dm_kcopyd_client *kc = job->kc; |
1da177e4 LT |
346 | |
347 | if (error) { | |
348 | if (job->rw == WRITE) | |
ce503f59 | 349 | job->write_err |= error; |
1da177e4 LT |
350 | else |
351 | job->read_err = 1; | |
352 | ||
eb69aca5 | 353 | if (!test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { |
8c0cbc2f MP |
354 | push(&kc->complete_jobs, job); |
355 | wake(kc); | |
1da177e4 LT |
356 | return; |
357 | } | |
358 | } | |
359 | ||
360 | if (job->rw == WRITE) | |
8c0cbc2f | 361 | push(&kc->complete_jobs, job); |
1da177e4 LT |
362 | |
363 | else { | |
364 | job->rw = WRITE; | |
8c0cbc2f | 365 | push(&kc->io_jobs, job); |
1da177e4 LT |
366 | } |
367 | ||
8c0cbc2f | 368 | wake(kc); |
1da177e4 LT |
369 | } |
370 | ||
371 | /* | |
372 | * Request io on as many buffer heads as we can currently get for | |
373 | * a particular job. | |
374 | */ | |
375 | static int run_io_job(struct kcopyd_job *job) | |
376 | { | |
377 | int r; | |
373a392b | 378 | struct dm_io_request io_req = { |
8d35d3e3 | 379 | .bi_rw = job->rw, |
373a392b MB |
380 | .mem.type = DM_IO_PAGE_LIST, |
381 | .mem.ptr.pl = job->pages, | |
382 | .mem.offset = job->offset, | |
383 | .notify.fn = complete_io, | |
384 | .notify.context = job, | |
385 | .client = job->kc->io_client, | |
386 | }; | |
1da177e4 | 387 | |
7eaceacc | 388 | if (job->rw == READ) |
373a392b | 389 | r = dm_io(&io_req, 1, &job->source, NULL); |
721a9602 | 390 | else |
373a392b | 391 | r = dm_io(&io_req, job->num_dests, job->dests, NULL); |
1da177e4 LT |
392 | |
393 | return r; | |
394 | } | |
395 | ||
396 | static int run_pages_job(struct kcopyd_job *job) | |
397 | { | |
398 | int r; | |
399 | ||
400 | job->nr_pages = dm_div_up(job->dests[0].count + job->offset, | |
401 | PAGE_SIZE >> 9); | |
402 | r = kcopyd_get_pages(job->kc, job->nr_pages, &job->pages); | |
403 | if (!r) { | |
404 | /* this job is ready for io */ | |
8c0cbc2f | 405 | push(&job->kc->io_jobs, job); |
1da177e4 LT |
406 | return 0; |
407 | } | |
408 | ||
409 | if (r == -ENOMEM) | |
410 | /* can't complete now */ | |
411 | return 1; | |
412 | ||
413 | return r; | |
414 | } | |
415 | ||
416 | /* | |
417 | * Run through a list for as long as possible. Returns the count | |
418 | * of successful jobs. | |
419 | */ | |
8c0cbc2f MP |
420 | static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc, |
421 | int (*fn) (struct kcopyd_job *)) | |
1da177e4 LT |
422 | { |
423 | struct kcopyd_job *job; | |
424 | int r, count = 0; | |
425 | ||
8c0cbc2f | 426 | while ((job = pop(jobs, kc))) { |
1da177e4 LT |
427 | |
428 | r = fn(job); | |
429 | ||
430 | if (r < 0) { | |
431 | /* error this rogue job */ | |
432 | if (job->rw == WRITE) | |
4cdc1d1f | 433 | job->write_err = (unsigned long) -1L; |
1da177e4 LT |
434 | else |
435 | job->read_err = 1; | |
8c0cbc2f | 436 | push(&kc->complete_jobs, job); |
1da177e4 LT |
437 | break; |
438 | } | |
439 | ||
440 | if (r > 0) { | |
441 | /* | |
442 | * We couldn't service this job ATM, so | |
443 | * push this job back onto the list. | |
444 | */ | |
b673c3a8 | 445 | push_head(jobs, job); |
1da177e4 LT |
446 | break; |
447 | } | |
448 | ||
449 | count++; | |
450 | } | |
451 | ||
452 | return count; | |
453 | } | |
454 | ||
455 | /* | |
456 | * kcopyd does this every time it's woken up. | |
457 | */ | |
8c0cbc2f | 458 | static void do_work(struct work_struct *work) |
1da177e4 | 459 | { |
8c0cbc2f MP |
460 | struct dm_kcopyd_client *kc = container_of(work, |
461 | struct dm_kcopyd_client, kcopyd_work); | |
7eaceacc | 462 | struct blk_plug plug; |
8c0cbc2f | 463 | |
1da177e4 LT |
464 | /* |
465 | * The order that these are called is *very* important. | |
466 | * complete jobs can free some pages for pages jobs. | |
467 | * Pages jobs when successful will jump onto the io jobs | |
468 | * list. io jobs call wake when they complete and it all | |
469 | * starts again. | |
470 | */ | |
7eaceacc | 471 | blk_start_plug(&plug); |
8c0cbc2f MP |
472 | process_jobs(&kc->complete_jobs, kc, run_complete_job); |
473 | process_jobs(&kc->pages_jobs, kc, run_pages_job); | |
474 | process_jobs(&kc->io_jobs, kc, run_io_job); | |
7eaceacc | 475 | blk_finish_plug(&plug); |
1da177e4 LT |
476 | } |
477 | ||
478 | /* | |
479 | * If we are copying a small region we just dispatch a single job | |
480 | * to do the copy, otherwise the io has to be split up into many | |
481 | * jobs. | |
482 | */ | |
483 | static void dispatch_job(struct kcopyd_job *job) | |
484 | { | |
8c0cbc2f MP |
485 | struct dm_kcopyd_client *kc = job->kc; |
486 | atomic_inc(&kc->nr_jobs); | |
9ca170a3 MP |
487 | if (unlikely(!job->source.count)) |
488 | push(&kc->complete_jobs, job); | |
489 | else | |
490 | push(&kc->pages_jobs, job); | |
8c0cbc2f | 491 | wake(kc); |
1da177e4 LT |
492 | } |
493 | ||
4cdc1d1f AK |
494 | static void segment_complete(int read_err, unsigned long write_err, |
495 | void *context) | |
1da177e4 LT |
496 | { |
497 | /* FIXME: tidy this function */ | |
498 | sector_t progress = 0; | |
499 | sector_t count = 0; | |
c6ea41fb MP |
500 | struct kcopyd_job *sub_job = (struct kcopyd_job *) context; |
501 | struct kcopyd_job *job = sub_job->master_job; | |
73830857 | 502 | struct dm_kcopyd_client *kc = job->kc; |
1da177e4 | 503 | |
def5b5b2 | 504 | mutex_lock(&job->lock); |
1da177e4 LT |
505 | |
506 | /* update the error */ | |
507 | if (read_err) | |
508 | job->read_err = 1; | |
509 | ||
510 | if (write_err) | |
ce503f59 | 511 | job->write_err |= write_err; |
1da177e4 LT |
512 | |
513 | /* | |
514 | * Only dispatch more work if there hasn't been an error. | |
515 | */ | |
516 | if ((!job->read_err && !job->write_err) || | |
eb69aca5 | 517 | test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { |
1da177e4 LT |
518 | /* get the next chunk of work */ |
519 | progress = job->progress; | |
520 | count = job->source.count - progress; | |
521 | if (count) { | |
522 | if (count > SUB_JOB_SIZE) | |
523 | count = SUB_JOB_SIZE; | |
524 | ||
525 | job->progress += count; | |
526 | } | |
527 | } | |
def5b5b2 | 528 | mutex_unlock(&job->lock); |
1da177e4 LT |
529 | |
530 | if (count) { | |
531 | int i; | |
1da177e4 LT |
532 | |
533 | *sub_job = *job; | |
534 | sub_job->source.sector += progress; | |
535 | sub_job->source.count = count; | |
536 | ||
537 | for (i = 0; i < job->num_dests; i++) { | |
538 | sub_job->dests[i].sector += progress; | |
539 | sub_job->dests[i].count = count; | |
540 | } | |
541 | ||
542 | sub_job->fn = segment_complete; | |
c6ea41fb | 543 | sub_job->context = sub_job; |
1da177e4 LT |
544 | dispatch_job(sub_job); |
545 | ||
546 | } else if (atomic_dec_and_test(&job->sub_jobs)) { | |
547 | ||
548 | /* | |
340cd444 MP |
549 | * Queue the completion callback to the kcopyd thread. |
550 | * | |
551 | * Some callers assume that all the completions are called | |
552 | * from a single thread and don't race with each other. | |
553 | * | |
554 | * We must not call the callback directly here because this | |
555 | * code may not be executing in the thread. | |
1da177e4 | 556 | */ |
340cd444 MP |
557 | push(&kc->complete_jobs, job); |
558 | wake(kc); | |
1da177e4 LT |
559 | } |
560 | } | |
561 | ||
562 | /* | |
c6ea41fb | 563 | * Create some sub jobs to share the work between them. |
1da177e4 | 564 | */ |
c6ea41fb | 565 | static void split_job(struct kcopyd_job *master_job) |
1da177e4 LT |
566 | { |
567 | int i; | |
568 | ||
c6ea41fb | 569 | atomic_inc(&master_job->kc->nr_jobs); |
340cd444 | 570 | |
c6ea41fb MP |
571 | atomic_set(&master_job->sub_jobs, SPLIT_COUNT); |
572 | for (i = 0; i < SPLIT_COUNT; i++) { | |
573 | master_job[i + 1].master_job = master_job; | |
574 | segment_complete(0, 0u, &master_job[i + 1]); | |
575 | } | |
1da177e4 LT |
576 | } |
577 | ||
eb69aca5 HM |
578 | int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, |
579 | unsigned int num_dests, struct dm_io_region *dests, | |
580 | unsigned int flags, dm_kcopyd_notify_fn fn, void *context) | |
1da177e4 LT |
581 | { |
582 | struct kcopyd_job *job; | |
583 | ||
584 | /* | |
c6ea41fb MP |
585 | * Allocate an array of jobs consisting of one master job |
586 | * followed by SPLIT_COUNT sub jobs. | |
1da177e4 | 587 | */ |
08d8757a | 588 | job = mempool_alloc(kc->job_pool, GFP_NOIO); |
1da177e4 LT |
589 | |
590 | /* | |
591 | * set up for the read. | |
592 | */ | |
593 | job->kc = kc; | |
594 | job->flags = flags; | |
595 | job->read_err = 0; | |
596 | job->write_err = 0; | |
597 | job->rw = READ; | |
598 | ||
599 | job->source = *from; | |
600 | ||
601 | job->num_dests = num_dests; | |
602 | memcpy(&job->dests, dests, sizeof(*dests) * num_dests); | |
603 | ||
604 | job->offset = 0; | |
605 | job->nr_pages = 0; | |
606 | job->pages = NULL; | |
607 | ||
608 | job->fn = fn; | |
609 | job->context = context; | |
c6ea41fb | 610 | job->master_job = job; |
1da177e4 | 611 | |
a705a34a | 612 | if (job->source.count <= SUB_JOB_SIZE) |
1da177e4 | 613 | dispatch_job(job); |
1da177e4 | 614 | else { |
def5b5b2 | 615 | mutex_init(&job->lock); |
1da177e4 LT |
616 | job->progress = 0; |
617 | split_job(job); | |
618 | } | |
619 | ||
620 | return 0; | |
621 | } | |
eb69aca5 | 622 | EXPORT_SYMBOL(dm_kcopyd_copy); |
1da177e4 LT |
623 | |
624 | /* | |
625 | * Cancels a kcopyd job, eg. someone might be deactivating a | |
626 | * mirror. | |
627 | */ | |
0b56306e | 628 | #if 0 |
1da177e4 LT |
629 | int kcopyd_cancel(struct kcopyd_job *job, int block) |
630 | { | |
631 | /* FIXME: finish */ | |
632 | return -1; | |
633 | } | |
0b56306e | 634 | #endif /* 0 */ |
1da177e4 LT |
635 | |
636 | /*----------------------------------------------------------------- | |
945fa4d2 | 637 | * Client setup |
1da177e4 | 638 | *---------------------------------------------------------------*/ |
d0471458 | 639 | int dm_kcopyd_client_create(unsigned min_pages, |
eb69aca5 | 640 | struct dm_kcopyd_client **result) |
1da177e4 | 641 | { |
945fa4d2 | 642 | int r = -ENOMEM; |
eb69aca5 | 643 | struct dm_kcopyd_client *kc; |
1da177e4 | 644 | |
1da177e4 | 645 | kc = kmalloc(sizeof(*kc), GFP_KERNEL); |
945fa4d2 MP |
646 | if (!kc) |
647 | return -ENOMEM; | |
1da177e4 | 648 | |
8c0cbc2f MP |
649 | spin_lock_init(&kc->job_lock); |
650 | INIT_LIST_HEAD(&kc->complete_jobs); | |
651 | INIT_LIST_HEAD(&kc->io_jobs); | |
652 | INIT_LIST_HEAD(&kc->pages_jobs); | |
653 | ||
08d8757a | 654 | kc->job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache); |
945fa4d2 MP |
655 | if (!kc->job_pool) |
656 | goto bad_slab; | |
08d8757a | 657 | |
8c0cbc2f | 658 | INIT_WORK(&kc->kcopyd_work, do_work); |
9c4376de TH |
659 | kc->kcopyd_wq = alloc_workqueue("kcopyd", |
660 | WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0); | |
945fa4d2 MP |
661 | if (!kc->kcopyd_wq) |
662 | goto bad_workqueue; | |
8c0cbc2f | 663 | |
1da177e4 | 664 | kc->pages = NULL; |
d0471458 MP |
665 | kc->nr_reserved_pages = kc->nr_free_pages = 0; |
666 | r = client_reserve_pages(kc, min_pages); | |
945fa4d2 MP |
667 | if (r) |
668 | goto bad_client_pages; | |
1da177e4 | 669 | |
bda8efec | 670 | kc->io_client = dm_io_client_create(); |
373a392b MB |
671 | if (IS_ERR(kc->io_client)) { |
672 | r = PTR_ERR(kc->io_client); | |
945fa4d2 | 673 | goto bad_io_client; |
1da177e4 LT |
674 | } |
675 | ||
138728dc AK |
676 | init_waitqueue_head(&kc->destroyq); |
677 | atomic_set(&kc->nr_jobs, 0); | |
678 | ||
1da177e4 LT |
679 | *result = kc; |
680 | return 0; | |
945fa4d2 MP |
681 | |
682 | bad_io_client: | |
683 | client_free_pages(kc); | |
684 | bad_client_pages: | |
685 | destroy_workqueue(kc->kcopyd_wq); | |
686 | bad_workqueue: | |
687 | mempool_destroy(kc->job_pool); | |
688 | bad_slab: | |
689 | kfree(kc); | |
690 | ||
691 | return r; | |
1da177e4 | 692 | } |
eb69aca5 | 693 | EXPORT_SYMBOL(dm_kcopyd_client_create); |
1da177e4 | 694 | |
eb69aca5 | 695 | void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc) |
1da177e4 | 696 | { |
138728dc AK |
697 | /* Wait for completion of all jobs submitted by this client. */ |
698 | wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs)); | |
699 | ||
8c0cbc2f MP |
700 | BUG_ON(!list_empty(&kc->complete_jobs)); |
701 | BUG_ON(!list_empty(&kc->io_jobs)); | |
702 | BUG_ON(!list_empty(&kc->pages_jobs)); | |
703 | destroy_workqueue(kc->kcopyd_wq); | |
373a392b | 704 | dm_io_client_destroy(kc->io_client); |
1da177e4 | 705 | client_free_pages(kc); |
08d8757a | 706 | mempool_destroy(kc->job_pool); |
1da177e4 | 707 | kfree(kc); |
1da177e4 | 708 | } |
eb69aca5 | 709 | EXPORT_SYMBOL(dm_kcopyd_client_destroy); |