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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/delay.h>
26#include <linux/device-mapper.h>
27#include <linux/dm-kcopyd.h>
28
29#include "dm.h"
30
31#define SUB_JOB_SIZE 128
32#define SPLIT_COUNT 8
33#define MIN_JOBS 8
34#define RESERVE_PAGES (DIV_ROUND_UP(SUB_JOB_SIZE << SECTOR_SHIFT, PAGE_SIZE))
35
36
37
38
39
40struct dm_kcopyd_client {
41 struct page_list *pages;
42 unsigned nr_reserved_pages;
43 unsigned nr_free_pages;
44
45 struct dm_io_client *io_client;
46
47 wait_queue_head_t destroyq;
48 atomic_t nr_jobs;
49
50 mempool_t *job_pool;
51
52 struct workqueue_struct *kcopyd_wq;
53 struct work_struct kcopyd_work;
54
55 struct dm_kcopyd_throttle *throttle;
56
57
58
59
60
61
62
63
64
65
66 spinlock_t job_lock;
67 struct list_head complete_jobs;
68 struct list_head io_jobs;
69 struct list_head pages_jobs;
70};
71
72static struct page_list zero_page_list;
73
74static DEFINE_SPINLOCK(throttle_spinlock);
75
76
77
78
79
80
81#define ACCOUNT_INTERVAL_SHIFT SHIFT_HZ
82
83
84
85
86
87
88
89
90
91#define SLEEP_MSEC 100
92
93
94
95
96
97#define MAX_SLEEPS 10
98
99static void io_job_start(struct dm_kcopyd_throttle *t)
100{
101 unsigned throttle, now, difference;
102 int slept = 0, skew;
103
104 if (unlikely(!t))
105 return;
106
107try_again:
108 spin_lock_irq(&throttle_spinlock);
109
110 throttle = ACCESS_ONCE(t->throttle);
111
112 if (likely(throttle >= 100))
113 goto skip_limit;
114
115 now = jiffies;
116 difference = now - t->last_jiffies;
117 t->last_jiffies = now;
118 if (t->num_io_jobs)
119 t->io_period += difference;
120 t->total_period += difference;
121
122
123
124
125 if (unlikely(t->io_period > t->total_period))
126 t->io_period = t->total_period;
127
128 if (unlikely(t->total_period >= (1 << ACCOUNT_INTERVAL_SHIFT))) {
129 int shift = fls(t->total_period >> ACCOUNT_INTERVAL_SHIFT);
130 t->total_period >>= shift;
131 t->io_period >>= shift;
132 }
133
134 skew = t->io_period - throttle * t->total_period / 100;
135
136 if (unlikely(skew > 0) && slept < MAX_SLEEPS) {
137 slept++;
138 spin_unlock_irq(&throttle_spinlock);
139 msleep(SLEEP_MSEC);
140 goto try_again;
141 }
142
143skip_limit:
144 t->num_io_jobs++;
145
146 spin_unlock_irq(&throttle_spinlock);
147}
148
149static void io_job_finish(struct dm_kcopyd_throttle *t)
150{
151 unsigned long flags;
152
153 if (unlikely(!t))
154 return;
155
156 spin_lock_irqsave(&throttle_spinlock, flags);
157
158 t->num_io_jobs--;
159
160 if (likely(ACCESS_ONCE(t->throttle) >= 100))
161 goto skip_limit;
162
163 if (!t->num_io_jobs) {
164 unsigned now, difference;
165
166 now = jiffies;
167 difference = now - t->last_jiffies;
168 t->last_jiffies = now;
169
170 t->io_period += difference;
171 t->total_period += difference;
172
173
174
175
176 if (unlikely(t->io_period > t->total_period))
177 t->io_period = t->total_period;
178 }
179
180skip_limit:
181 spin_unlock_irqrestore(&throttle_spinlock, flags);
182}
183
184
185static void wake(struct dm_kcopyd_client *kc)
186{
187 queue_work(kc->kcopyd_wq, &kc->kcopyd_work);
188}
189
190
191
192
193static struct page_list *alloc_pl(gfp_t gfp)
194{
195 struct page_list *pl;
196
197 pl = kmalloc(sizeof(*pl), gfp);
198 if (!pl)
199 return NULL;
200
201 pl->page = alloc_page(gfp);
202 if (!pl->page) {
203 kfree(pl);
204 return NULL;
205 }
206
207 return pl;
208}
209
210static void free_pl(struct page_list *pl)
211{
212 __free_page(pl->page);
213 kfree(pl);
214}
215
216
217
218
219
220static void kcopyd_put_pages(struct dm_kcopyd_client *kc, struct page_list *pl)
221{
222 struct page_list *next;
223
224 do {
225 next = pl->next;
226
227 if (kc->nr_free_pages >= kc->nr_reserved_pages)
228 free_pl(pl);
229 else {
230 pl->next = kc->pages;
231 kc->pages = pl;
232 kc->nr_free_pages++;
233 }
234
235 pl = next;
236 } while (pl);
237}
238
239static int kcopyd_get_pages(struct dm_kcopyd_client *kc,
240 unsigned int nr, struct page_list **pages)
241{
242 struct page_list *pl;
243
244 *pages = NULL;
245
246 do {
247 pl = alloc_pl(__GFP_NOWARN | __GFP_NORETRY | __GFP_KSWAPD_RECLAIM);
248 if (unlikely(!pl)) {
249
250 pl = kc->pages;
251 if (unlikely(!pl))
252 goto out_of_memory;
253 kc->pages = pl->next;
254 kc->nr_free_pages--;
255 }
256 pl->next = *pages;
257 *pages = pl;
258 } while (--nr);
259
260 return 0;
261
262out_of_memory:
263 if (*pages)
264 kcopyd_put_pages(kc, *pages);
265 return -ENOMEM;
266}
267
268
269
270
271static void drop_pages(struct page_list *pl)
272{
273 struct page_list *next;
274
275 while (pl) {
276 next = pl->next;
277 free_pl(pl);
278 pl = next;
279 }
280}
281
282
283
284
285static int client_reserve_pages(struct dm_kcopyd_client *kc, unsigned nr_pages)
286{
287 unsigned i;
288 struct page_list *pl = NULL, *next;
289
290 for (i = 0; i < nr_pages; i++) {
291 next = alloc_pl(GFP_KERNEL);
292 if (!next) {
293 if (pl)
294 drop_pages(pl);
295 return -ENOMEM;
296 }
297 next->next = pl;
298 pl = next;
299 }
300
301 kc->nr_reserved_pages += nr_pages;
302 kcopyd_put_pages(kc, pl);
303
304 return 0;
305}
306
307static void client_free_pages(struct dm_kcopyd_client *kc)
308{
309 BUG_ON(kc->nr_free_pages != kc->nr_reserved_pages);
310 drop_pages(kc->pages);
311 kc->pages = NULL;
312 kc->nr_free_pages = kc->nr_reserved_pages = 0;
313}
314
315
316
317
318
319
320struct kcopyd_job {
321 struct dm_kcopyd_client *kc;
322 struct list_head list;
323 unsigned long flags;
324
325
326
327
328 int read_err;
329 unsigned long write_err;
330
331
332
333
334 int rw;
335 struct dm_io_region source;
336
337
338
339
340 unsigned int num_dests;
341 struct dm_io_region dests[DM_KCOPYD_MAX_REGIONS];
342
343 struct page_list *pages;
344
345
346
347
348
349 dm_kcopyd_notify_fn fn;
350 void *context;
351
352
353
354
355
356 struct mutex lock;
357 atomic_t sub_jobs;
358 sector_t progress;
359
360 struct kcopyd_job *master_job;
361};
362
363static struct kmem_cache *_job_cache;
364
365int __init dm_kcopyd_init(void)
366{
367 _job_cache = kmem_cache_create("kcopyd_job",
368 sizeof(struct kcopyd_job) * (SPLIT_COUNT + 1),
369 __alignof__(struct kcopyd_job), 0, NULL);
370 if (!_job_cache)
371 return -ENOMEM;
372
373 zero_page_list.next = &zero_page_list;
374 zero_page_list.page = ZERO_PAGE(0);
375
376 return 0;
377}
378
379void dm_kcopyd_exit(void)
380{
381 kmem_cache_destroy(_job_cache);
382 _job_cache = NULL;
383}
384
385
386
387
388
389static struct kcopyd_job *pop(struct list_head *jobs,
390 struct dm_kcopyd_client *kc)
391{
392 struct kcopyd_job *job = NULL;
393 unsigned long flags;
394
395 spin_lock_irqsave(&kc->job_lock, flags);
396
397 if (!list_empty(jobs)) {
398 job = list_entry(jobs->next, struct kcopyd_job, list);
399 list_del(&job->list);
400 }
401 spin_unlock_irqrestore(&kc->job_lock, flags);
402
403 return job;
404}
405
406static void push(struct list_head *jobs, struct kcopyd_job *job)
407{
408 unsigned long flags;
409 struct dm_kcopyd_client *kc = job->kc;
410
411 spin_lock_irqsave(&kc->job_lock, flags);
412 list_add_tail(&job->list, jobs);
413 spin_unlock_irqrestore(&kc->job_lock, flags);
414}
415
416
417static void push_head(struct list_head *jobs, struct kcopyd_job *job)
418{
419 unsigned long flags;
420 struct dm_kcopyd_client *kc = job->kc;
421
422 spin_lock_irqsave(&kc->job_lock, flags);
423 list_add(&job->list, jobs);
424 spin_unlock_irqrestore(&kc->job_lock, flags);
425}
426
427
428
429
430
431
432
433
434
435
436static int run_complete_job(struct kcopyd_job *job)
437{
438 void *context = job->context;
439 int read_err = job->read_err;
440 unsigned long write_err = job->write_err;
441 dm_kcopyd_notify_fn fn = job->fn;
442 struct dm_kcopyd_client *kc = job->kc;
443
444 if (job->pages && job->pages != &zero_page_list)
445 kcopyd_put_pages(kc, job->pages);
446
447
448
449
450 if (job->master_job == job)
451 mempool_free(job, kc->job_pool);
452 fn(read_err, write_err, context);
453
454 if (atomic_dec_and_test(&kc->nr_jobs))
455 wake_up(&kc->destroyq);
456
457 return 0;
458}
459
460static void complete_io(unsigned long error, void *context)
461{
462 struct kcopyd_job *job = (struct kcopyd_job *) context;
463 struct dm_kcopyd_client *kc = job->kc;
464
465 io_job_finish(kc->throttle);
466
467 if (error) {
468 if (job->rw & WRITE)
469 job->write_err |= error;
470 else
471 job->read_err = 1;
472
473 if (!test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) {
474 push(&kc->complete_jobs, job);
475 wake(kc);
476 return;
477 }
478 }
479
480 if (job->rw & WRITE)
481 push(&kc->complete_jobs, job);
482
483 else {
484 job->rw = WRITE;
485 push(&kc->io_jobs, job);
486 }
487
488 wake(kc);
489}
490
491
492
493
494
495static int run_io_job(struct kcopyd_job *job)
496{
497 int r;
498 struct dm_io_request io_req = {
499 .bi_rw = job->rw,
500 .mem.type = DM_IO_PAGE_LIST,
501 .mem.ptr.pl = job->pages,
502 .mem.offset = 0,
503 .notify.fn = complete_io,
504 .notify.context = job,
505 .client = job->kc->io_client,
506 };
507
508 io_job_start(job->kc->throttle);
509
510 if (job->rw == READ)
511 r = dm_io(&io_req, 1, &job->source, NULL);
512 else
513 r = dm_io(&io_req, job->num_dests, job->dests, NULL);
514
515 return r;
516}
517
518static int run_pages_job(struct kcopyd_job *job)
519{
520 int r;
521 unsigned nr_pages = dm_div_up(job->dests[0].count, PAGE_SIZE >> 9);
522
523 r = kcopyd_get_pages(job->kc, nr_pages, &job->pages);
524 if (!r) {
525
526 push(&job->kc->io_jobs, job);
527 return 0;
528 }
529
530 if (r == -ENOMEM)
531
532 return 1;
533
534 return r;
535}
536
537
538
539
540
541static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc,
542 int (*fn) (struct kcopyd_job *))
543{
544 struct kcopyd_job *job;
545 int r, count = 0;
546
547 while ((job = pop(jobs, kc))) {
548
549 r = fn(job);
550
551 if (r < 0) {
552
553 if (job->rw & WRITE)
554 job->write_err = (unsigned long) -1L;
555 else
556 job->read_err = 1;
557 push(&kc->complete_jobs, job);
558 break;
559 }
560
561 if (r > 0) {
562
563
564
565
566 push_head(jobs, job);
567 break;
568 }
569
570 count++;
571 }
572
573 return count;
574}
575
576
577
578
579static void do_work(struct work_struct *work)
580{
581 struct dm_kcopyd_client *kc = container_of(work,
582 struct dm_kcopyd_client, kcopyd_work);
583 struct blk_plug plug;
584
585
586
587
588
589
590
591
592 blk_start_plug(&plug);
593 process_jobs(&kc->complete_jobs, kc, run_complete_job);
594 process_jobs(&kc->pages_jobs, kc, run_pages_job);
595 process_jobs(&kc->io_jobs, kc, run_io_job);
596 blk_finish_plug(&plug);
597}
598
599
600
601
602
603
604static void dispatch_job(struct kcopyd_job *job)
605{
606 struct dm_kcopyd_client *kc = job->kc;
607 atomic_inc(&kc->nr_jobs);
608 if (unlikely(!job->source.count))
609 push(&kc->complete_jobs, job);
610 else if (job->pages == &zero_page_list)
611 push(&kc->io_jobs, job);
612 else
613 push(&kc->pages_jobs, job);
614 wake(kc);
615}
616
617static void segment_complete(int read_err, unsigned long write_err,
618 void *context)
619{
620
621 sector_t progress = 0;
622 sector_t count = 0;
623 struct kcopyd_job *sub_job = (struct kcopyd_job *) context;
624 struct kcopyd_job *job = sub_job->master_job;
625 struct dm_kcopyd_client *kc = job->kc;
626
627 mutex_lock(&job->lock);
628
629
630 if (read_err)
631 job->read_err = 1;
632
633 if (write_err)
634 job->write_err |= write_err;
635
636
637
638
639 if ((!job->read_err && !job->write_err) ||
640 test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) {
641
642 progress = job->progress;
643 count = job->source.count - progress;
644 if (count) {
645 if (count > SUB_JOB_SIZE)
646 count = SUB_JOB_SIZE;
647
648 job->progress += count;
649 }
650 }
651 mutex_unlock(&job->lock);
652
653 if (count) {
654 int i;
655
656 *sub_job = *job;
657 sub_job->source.sector += progress;
658 sub_job->source.count = count;
659
660 for (i = 0; i < job->num_dests; i++) {
661 sub_job->dests[i].sector += progress;
662 sub_job->dests[i].count = count;
663 }
664
665 sub_job->fn = segment_complete;
666 sub_job->context = sub_job;
667 dispatch_job(sub_job);
668
669 } else if (atomic_dec_and_test(&job->sub_jobs)) {
670
671
672
673
674
675
676
677
678
679
680 push(&kc->complete_jobs, job);
681 wake(kc);
682 }
683}
684
685
686
687
688static void split_job(struct kcopyd_job *master_job)
689{
690 int i;
691
692 atomic_inc(&master_job->kc->nr_jobs);
693
694 atomic_set(&master_job->sub_jobs, SPLIT_COUNT);
695 for (i = 0; i < SPLIT_COUNT; i++) {
696 master_job[i + 1].master_job = master_job;
697 segment_complete(0, 0u, &master_job[i + 1]);
698 }
699}
700
701int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
702 unsigned int num_dests, struct dm_io_region *dests,
703 unsigned int flags, dm_kcopyd_notify_fn fn, void *context)
704{
705 struct kcopyd_job *job;
706 int i;
707
708
709
710
711
712 job = mempool_alloc(kc->job_pool, GFP_NOIO);
713
714
715
716
717 job->kc = kc;
718 job->flags = flags;
719 job->read_err = 0;
720 job->write_err = 0;
721
722 job->num_dests = num_dests;
723 memcpy(&job->dests, dests, sizeof(*dests) * num_dests);
724
725 if (from) {
726 job->source = *from;
727 job->pages = NULL;
728 job->rw = READ;
729 } else {
730 memset(&job->source, 0, sizeof job->source);
731 job->source.count = job->dests[0].count;
732 job->pages = &zero_page_list;
733
734
735
736
737 job->rw = WRITE | REQ_WRITE_SAME;
738 for (i = 0; i < job->num_dests; i++)
739 if (!bdev_write_same(job->dests[i].bdev)) {
740 job->rw = WRITE;
741 break;
742 }
743 }
744
745 job->fn = fn;
746 job->context = context;
747 job->master_job = job;
748
749 if (job->source.count <= SUB_JOB_SIZE)
750 dispatch_job(job);
751 else {
752 mutex_init(&job->lock);
753 job->progress = 0;
754 split_job(job);
755 }
756
757 return 0;
758}
759EXPORT_SYMBOL(dm_kcopyd_copy);
760
761int dm_kcopyd_zero(struct dm_kcopyd_client *kc,
762 unsigned num_dests, struct dm_io_region *dests,
763 unsigned flags, dm_kcopyd_notify_fn fn, void *context)
764{
765 return dm_kcopyd_copy(kc, NULL, num_dests, dests, flags, fn, context);
766}
767EXPORT_SYMBOL(dm_kcopyd_zero);
768
769void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
770 dm_kcopyd_notify_fn fn, void *context)
771{
772 struct kcopyd_job *job;
773
774 job = mempool_alloc(kc->job_pool, GFP_NOIO);
775
776 memset(job, 0, sizeof(struct kcopyd_job));
777 job->kc = kc;
778 job->fn = fn;
779 job->context = context;
780 job->master_job = job;
781
782 atomic_inc(&kc->nr_jobs);
783
784 return job;
785}
786EXPORT_SYMBOL(dm_kcopyd_prepare_callback);
787
788void dm_kcopyd_do_callback(void *j, int read_err, unsigned long write_err)
789{
790 struct kcopyd_job *job = j;
791 struct dm_kcopyd_client *kc = job->kc;
792
793 job->read_err = read_err;
794 job->write_err = write_err;
795
796 push(&kc->complete_jobs, job);
797 wake(kc);
798}
799EXPORT_SYMBOL(dm_kcopyd_do_callback);
800
801
802
803
804
805#if 0
806int kcopyd_cancel(struct kcopyd_job *job, int block)
807{
808
809 return -1;
810}
811#endif
812
813
814
815
816struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle)
817{
818 int r = -ENOMEM;
819 struct dm_kcopyd_client *kc;
820
821 kc = kmalloc(sizeof(*kc), GFP_KERNEL);
822 if (!kc)
823 return ERR_PTR(-ENOMEM);
824
825 spin_lock_init(&kc->job_lock);
826 INIT_LIST_HEAD(&kc->complete_jobs);
827 INIT_LIST_HEAD(&kc->io_jobs);
828 INIT_LIST_HEAD(&kc->pages_jobs);
829 kc->throttle = throttle;
830
831 kc->job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache);
832 if (!kc->job_pool)
833 goto bad_slab;
834
835 INIT_WORK(&kc->kcopyd_work, do_work);
836 kc->kcopyd_wq = alloc_workqueue("kcopyd", WQ_MEM_RECLAIM, 0);
837 if (!kc->kcopyd_wq)
838 goto bad_workqueue;
839
840 kc->pages = NULL;
841 kc->nr_reserved_pages = kc->nr_free_pages = 0;
842 r = client_reserve_pages(kc, RESERVE_PAGES);
843 if (r)
844 goto bad_client_pages;
845
846 kc->io_client = dm_io_client_create();
847 if (IS_ERR(kc->io_client)) {
848 r = PTR_ERR(kc->io_client);
849 goto bad_io_client;
850 }
851
852 init_waitqueue_head(&kc->destroyq);
853 atomic_set(&kc->nr_jobs, 0);
854
855 return kc;
856
857bad_io_client:
858 client_free_pages(kc);
859bad_client_pages:
860 destroy_workqueue(kc->kcopyd_wq);
861bad_workqueue:
862 mempool_destroy(kc->job_pool);
863bad_slab:
864 kfree(kc);
865
866 return ERR_PTR(r);
867}
868EXPORT_SYMBOL(dm_kcopyd_client_create);
869
870void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc)
871{
872
873 wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs));
874
875 BUG_ON(!list_empty(&kc->complete_jobs));
876 BUG_ON(!list_empty(&kc->io_jobs));
877 BUG_ON(!list_empty(&kc->pages_jobs));
878 destroy_workqueue(kc->kcopyd_wq);
879 dm_io_client_destroy(kc->io_client);
880 client_free_pages(kc);
881 mempool_destroy(kc->job_pool);
882 kfree(kc);
883}
884EXPORT_SYMBOL(dm_kcopyd_client_destroy);
885