1
2
3
4
5
6
7
8#include <linux/kernel.h>
9#include <linux/init.h>
10#include <linux/errno.h>
11#include <linux/sched/signal.h>
12#include <linux/mm.h>
13#include <linux/mmu_context.h>
14#include <linux/sched/mm.h>
15#include <linux/percpu.h>
16#include <linux/slab.h>
17#include <linux/kthread.h>
18#include <linux/rculist_nulls.h>
19#include <linux/fs_struct.h>
20#include <linux/task_work.h>
21
22#include "io-wq.h"
23
24#define WORKER_IDLE_TIMEOUT (5 * HZ)
25
26enum {
27 IO_WORKER_F_UP = 1,
28 IO_WORKER_F_RUNNING = 2,
29 IO_WORKER_F_FREE = 4,
30 IO_WORKER_F_EXITING = 8,
31 IO_WORKER_F_FIXED = 16,
32 IO_WORKER_F_BOUND = 32,
33};
34
35enum {
36 IO_WQ_BIT_EXIT = 0,
37 IO_WQ_BIT_CANCEL = 1,
38 IO_WQ_BIT_ERROR = 2,
39};
40
41enum {
42 IO_WQE_FLAG_STALLED = 1,
43};
44
45
46
47
48struct io_worker {
49 refcount_t ref;
50 unsigned flags;
51 struct hlist_nulls_node nulls_node;
52 struct list_head all_list;
53 struct task_struct *task;
54 struct io_wqe *wqe;
55
56 struct io_wq_work *cur_work;
57 spinlock_t lock;
58
59 struct rcu_head rcu;
60 struct mm_struct *mm;
61 const struct cred *cur_creds;
62 const struct cred *saved_creds;
63 struct files_struct *restore_files;
64 struct fs_struct *restore_fs;
65};
66
67#if BITS_PER_LONG == 64
68#define IO_WQ_HASH_ORDER 6
69#else
70#define IO_WQ_HASH_ORDER 5
71#endif
72
73#define IO_WQ_NR_HASH_BUCKETS (1u << IO_WQ_HASH_ORDER)
74
75struct io_wqe_acct {
76 unsigned nr_workers;
77 unsigned max_workers;
78 atomic_t nr_running;
79};
80
81enum {
82 IO_WQ_ACCT_BOUND,
83 IO_WQ_ACCT_UNBOUND,
84};
85
86
87
88
89struct io_wqe {
90 struct {
91 spinlock_t lock;
92 struct io_wq_work_list work_list;
93 unsigned long hash_map;
94 unsigned flags;
95 } ____cacheline_aligned_in_smp;
96
97 int node;
98 struct io_wqe_acct acct[2];
99
100 struct hlist_nulls_head free_list;
101 struct list_head all_list;
102
103 struct io_wq *wq;
104 struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS];
105};
106
107
108
109
110struct io_wq {
111 struct io_wqe **wqes;
112 unsigned long state;
113
114 free_work_fn *free_work;
115
116 struct task_struct *manager;
117 struct user_struct *user;
118 refcount_t refs;
119 struct completion done;
120
121 refcount_t use_refs;
122};
123
124static bool io_worker_get(struct io_worker *worker)
125{
126 return refcount_inc_not_zero(&worker->ref);
127}
128
129static void io_worker_release(struct io_worker *worker)
130{
131 if (refcount_dec_and_test(&worker->ref))
132 wake_up_process(worker->task);
133}
134
135
136
137
138
139
140static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker)
141{
142 bool dropped_lock = false;
143
144 if (worker->saved_creds) {
145 revert_creds(worker->saved_creds);
146 worker->cur_creds = worker->saved_creds = NULL;
147 }
148
149 if (current->files != worker->restore_files) {
150 __acquire(&wqe->lock);
151 spin_unlock_irq(&wqe->lock);
152 dropped_lock = true;
153
154 task_lock(current);
155 current->files = worker->restore_files;
156 task_unlock(current);
157 }
158
159 if (current->fs != worker->restore_fs)
160 current->fs = worker->restore_fs;
161
162
163
164
165
166 if (worker->mm) {
167 if (!dropped_lock) {
168 __acquire(&wqe->lock);
169 spin_unlock_irq(&wqe->lock);
170 dropped_lock = true;
171 }
172 __set_current_state(TASK_RUNNING);
173 set_fs(KERNEL_DS);
174 unuse_mm(worker->mm);
175 mmput(worker->mm);
176 worker->mm = NULL;
177 }
178
179 return dropped_lock;
180}
181
182static inline struct io_wqe_acct *io_work_get_acct(struct io_wqe *wqe,
183 struct io_wq_work *work)
184{
185 if (work->flags & IO_WQ_WORK_UNBOUND)
186 return &wqe->acct[IO_WQ_ACCT_UNBOUND];
187
188 return &wqe->acct[IO_WQ_ACCT_BOUND];
189}
190
191static inline struct io_wqe_acct *io_wqe_get_acct(struct io_wqe *wqe,
192 struct io_worker *worker)
193{
194 if (worker->flags & IO_WORKER_F_BOUND)
195 return &wqe->acct[IO_WQ_ACCT_BOUND];
196
197 return &wqe->acct[IO_WQ_ACCT_UNBOUND];
198}
199
200static void io_worker_exit(struct io_worker *worker)
201{
202 struct io_wqe *wqe = worker->wqe;
203 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
204 unsigned nr_workers;
205
206
207
208
209
210 set_current_state(TASK_INTERRUPTIBLE);
211 if (!refcount_dec_and_test(&worker->ref))
212 schedule();
213 __set_current_state(TASK_RUNNING);
214
215 preempt_disable();
216 current->flags &= ~PF_IO_WORKER;
217 if (worker->flags & IO_WORKER_F_RUNNING)
218 atomic_dec(&acct->nr_running);
219 if (!(worker->flags & IO_WORKER_F_BOUND))
220 atomic_dec(&wqe->wq->user->processes);
221 worker->flags = 0;
222 preempt_enable();
223
224 spin_lock_irq(&wqe->lock);
225 hlist_nulls_del_rcu(&worker->nulls_node);
226 list_del_rcu(&worker->all_list);
227 if (__io_worker_unuse(wqe, worker)) {
228 __release(&wqe->lock);
229 spin_lock_irq(&wqe->lock);
230 }
231 acct->nr_workers--;
232 nr_workers = wqe->acct[IO_WQ_ACCT_BOUND].nr_workers +
233 wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers;
234 spin_unlock_irq(&wqe->lock);
235
236
237 if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs))
238 complete(&wqe->wq->done);
239
240 kfree_rcu(worker, rcu);
241}
242
243static inline bool io_wqe_run_queue(struct io_wqe *wqe)
244 __must_hold(wqe->lock)
245{
246 if (!wq_list_empty(&wqe->work_list) &&
247 !(wqe->flags & IO_WQE_FLAG_STALLED))
248 return true;
249 return false;
250}
251
252
253
254
255
256static bool io_wqe_activate_free_worker(struct io_wqe *wqe)
257 __must_hold(RCU)
258{
259 struct hlist_nulls_node *n;
260 struct io_worker *worker;
261
262 n = rcu_dereference(hlist_nulls_first_rcu(&wqe->free_list));
263 if (is_a_nulls(n))
264 return false;
265
266 worker = hlist_nulls_entry(n, struct io_worker, nulls_node);
267 if (io_worker_get(worker)) {
268 wake_up_process(worker->task);
269 io_worker_release(worker);
270 return true;
271 }
272
273 return false;
274}
275
276
277
278
279
280static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
281{
282 bool ret;
283
284
285
286
287
288 WARN_ON_ONCE(!acct->max_workers);
289
290 rcu_read_lock();
291 ret = io_wqe_activate_free_worker(wqe);
292 rcu_read_unlock();
293
294 if (!ret && acct->nr_workers < acct->max_workers)
295 wake_up_process(wqe->wq->manager);
296}
297
298static void io_wqe_inc_running(struct io_wqe *wqe, struct io_worker *worker)
299{
300 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
301
302 atomic_inc(&acct->nr_running);
303}
304
305static void io_wqe_dec_running(struct io_wqe *wqe, struct io_worker *worker)
306 __must_hold(wqe->lock)
307{
308 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
309
310 if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe))
311 io_wqe_wake_worker(wqe, acct);
312}
313
314static void io_worker_start(struct io_wqe *wqe, struct io_worker *worker)
315{
316 allow_kernel_signal(SIGINT);
317
318 current->flags |= PF_IO_WORKER;
319
320 worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
321 worker->restore_files = current->files;
322 worker->restore_fs = current->fs;
323 io_wqe_inc_running(wqe, worker);
324}
325
326
327
328
329
330static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
331 struct io_wq_work *work)
332 __must_hold(wqe->lock)
333{
334 bool worker_bound, work_bound;
335
336 if (worker->flags & IO_WORKER_F_FREE) {
337 worker->flags &= ~IO_WORKER_F_FREE;
338 hlist_nulls_del_init_rcu(&worker->nulls_node);
339 }
340
341
342
343
344
345 worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
346 work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
347 if (worker_bound != work_bound) {
348 io_wqe_dec_running(wqe, worker);
349 if (work_bound) {
350 worker->flags |= IO_WORKER_F_BOUND;
351 wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
352 wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
353 atomic_dec(&wqe->wq->user->processes);
354 } else {
355 worker->flags &= ~IO_WORKER_F_BOUND;
356 wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
357 wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
358 atomic_inc(&wqe->wq->user->processes);
359 }
360 io_wqe_inc_running(wqe, worker);
361 }
362}
363
364
365
366
367
368
369
370
371static bool __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker)
372 __must_hold(wqe->lock)
373{
374 if (!(worker->flags & IO_WORKER_F_FREE)) {
375 worker->flags |= IO_WORKER_F_FREE;
376 hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
377 }
378
379 return __io_worker_unuse(wqe, worker);
380}
381
382static inline unsigned int io_get_work_hash(struct io_wq_work *work)
383{
384 return work->flags >> IO_WQ_HASH_SHIFT;
385}
386
387static struct io_wq_work *io_get_next_work(struct io_wqe *wqe)
388 __must_hold(wqe->lock)
389{
390 struct io_wq_work_node *node, *prev;
391 struct io_wq_work *work, *tail;
392 unsigned int hash;
393
394 wq_list_for_each(node, prev, &wqe->work_list) {
395 work = container_of(node, struct io_wq_work, list);
396
397
398 if (!io_wq_is_hashed(work)) {
399 wq_list_del(&wqe->work_list, node, prev);
400 return work;
401 }
402
403
404 hash = io_get_work_hash(work);
405 if (!(wqe->hash_map & BIT(hash))) {
406 wqe->hash_map |= BIT(hash);
407
408 tail = wqe->hash_tail[hash];
409 wqe->hash_tail[hash] = NULL;
410 wq_list_cut(&wqe->work_list, &tail->list, prev);
411 return work;
412 }
413 }
414
415 return NULL;
416}
417
418static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work)
419{
420 if (worker->mm) {
421 unuse_mm(worker->mm);
422 mmput(worker->mm);
423 worker->mm = NULL;
424 }
425 if (!work->mm) {
426 set_fs(KERNEL_DS);
427 return;
428 }
429 if (mmget_not_zero(work->mm)) {
430 use_mm(work->mm);
431 if (!worker->mm)
432 set_fs(USER_DS);
433 worker->mm = work->mm;
434
435 work->mm = NULL;
436 return;
437 }
438
439
440 work->flags |= IO_WQ_WORK_CANCEL;
441}
442
443static void io_wq_switch_creds(struct io_worker *worker,
444 struct io_wq_work *work)
445{
446 const struct cred *old_creds = override_creds(work->creds);
447
448 worker->cur_creds = work->creds;
449 if (worker->saved_creds)
450 put_cred(old_creds);
451 else
452 worker->saved_creds = old_creds;
453}
454
455static void io_impersonate_work(struct io_worker *worker,
456 struct io_wq_work *work)
457{
458 if (work->files && current->files != work->files) {
459 task_lock(current);
460 current->files = work->files;
461 task_unlock(current);
462 }
463 if (work->fs && current->fs != work->fs)
464 current->fs = work->fs;
465 if (work->mm != worker->mm)
466 io_wq_switch_mm(worker, work);
467 if (worker->cur_creds != work->creds)
468 io_wq_switch_creds(worker, work);
469}
470
471static void io_assign_current_work(struct io_worker *worker,
472 struct io_wq_work *work)
473{
474 if (work) {
475
476 if (signal_pending(current))
477 flush_signals(current);
478 cond_resched();
479 }
480
481 spin_lock_irq(&worker->lock);
482 worker->cur_work = work;
483 spin_unlock_irq(&worker->lock);
484}
485
486static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work);
487
488static void io_worker_handle_work(struct io_worker *worker)
489 __releases(wqe->lock)
490{
491 struct io_wqe *wqe = worker->wqe;
492 struct io_wq *wq = wqe->wq;
493
494 do {
495 struct io_wq_work *work;
496 unsigned int hash;
497get_next:
498
499
500
501
502
503
504
505 work = io_get_next_work(wqe);
506 if (work)
507 __io_worker_busy(wqe, worker, work);
508 else if (!wq_list_empty(&wqe->work_list))
509 wqe->flags |= IO_WQE_FLAG_STALLED;
510
511 spin_unlock_irq(&wqe->lock);
512 if (!work)
513 break;
514 io_assign_current_work(worker, work);
515
516
517 do {
518 struct io_wq_work *old_work, *next_hashed, *linked;
519
520 next_hashed = wq_next_work(work);
521 io_impersonate_work(worker, work);
522
523
524
525
526 if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
527 work->flags |= IO_WQ_WORK_CANCEL;
528
529 hash = io_get_work_hash(work);
530 linked = old_work = work;
531 linked->func(&linked);
532 linked = (old_work == linked) ? NULL : linked;
533
534 work = next_hashed;
535 if (!work && linked && !io_wq_is_hashed(linked)) {
536 work = linked;
537 linked = NULL;
538 }
539 io_assign_current_work(worker, work);
540 wq->free_work(old_work);
541
542 if (linked)
543 io_wqe_enqueue(wqe, linked);
544
545 if (hash != -1U && !next_hashed) {
546 spin_lock_irq(&wqe->lock);
547 wqe->hash_map &= ~BIT_ULL(hash);
548 wqe->flags &= ~IO_WQE_FLAG_STALLED;
549
550 hash = -1U;
551
552 if (!work)
553 goto get_next;
554 spin_unlock_irq(&wqe->lock);
555 }
556 } while (work);
557
558 spin_lock_irq(&wqe->lock);
559 } while (1);
560}
561
562static int io_wqe_worker(void *data)
563{
564 struct io_worker *worker = data;
565 struct io_wqe *wqe = worker->wqe;
566 struct io_wq *wq = wqe->wq;
567
568 io_worker_start(wqe, worker);
569
570 while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
571 set_current_state(TASK_INTERRUPTIBLE);
572loop:
573 spin_lock_irq(&wqe->lock);
574 if (io_wqe_run_queue(wqe)) {
575 __set_current_state(TASK_RUNNING);
576 io_worker_handle_work(worker);
577 goto loop;
578 }
579
580 if (__io_worker_idle(wqe, worker)) {
581 __release(&wqe->lock);
582 goto loop;
583 }
584 spin_unlock_irq(&wqe->lock);
585 if (signal_pending(current))
586 flush_signals(current);
587 if (schedule_timeout(WORKER_IDLE_TIMEOUT))
588 continue;
589
590 if (test_bit(IO_WQ_BIT_EXIT, &wq->state) ||
591 !(worker->flags & IO_WORKER_F_FIXED))
592 break;
593 }
594
595 if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
596 spin_lock_irq(&wqe->lock);
597 if (!wq_list_empty(&wqe->work_list))
598 io_worker_handle_work(worker);
599 else
600 spin_unlock_irq(&wqe->lock);
601 }
602
603 io_worker_exit(worker);
604 return 0;
605}
606
607
608
609
610void io_wq_worker_running(struct task_struct *tsk)
611{
612 struct io_worker *worker = kthread_data(tsk);
613 struct io_wqe *wqe = worker->wqe;
614
615 if (!(worker->flags & IO_WORKER_F_UP))
616 return;
617 if (worker->flags & IO_WORKER_F_RUNNING)
618 return;
619 worker->flags |= IO_WORKER_F_RUNNING;
620 io_wqe_inc_running(wqe, worker);
621}
622
623
624
625
626
627
628void io_wq_worker_sleeping(struct task_struct *tsk)
629{
630 struct io_worker *worker = kthread_data(tsk);
631 struct io_wqe *wqe = worker->wqe;
632
633 if (!(worker->flags & IO_WORKER_F_UP))
634 return;
635 if (!(worker->flags & IO_WORKER_F_RUNNING))
636 return;
637
638 worker->flags &= ~IO_WORKER_F_RUNNING;
639
640 spin_lock_irq(&wqe->lock);
641 io_wqe_dec_running(wqe, worker);
642 spin_unlock_irq(&wqe->lock);
643}
644
645static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
646{
647 struct io_wqe_acct *acct =&wqe->acct[index];
648 struct io_worker *worker;
649
650 worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, wqe->node);
651 if (!worker)
652 return false;
653
654 refcount_set(&worker->ref, 1);
655 worker->nulls_node.pprev = NULL;
656 worker->wqe = wqe;
657 spin_lock_init(&worker->lock);
658
659 worker->task = kthread_create_on_node(io_wqe_worker, worker, wqe->node,
660 "io_wqe_worker-%d/%d", index, wqe->node);
661 if (IS_ERR(worker->task)) {
662 kfree(worker);
663 return false;
664 }
665
666 spin_lock_irq(&wqe->lock);
667 hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
668 list_add_tail_rcu(&worker->all_list, &wqe->all_list);
669 worker->flags |= IO_WORKER_F_FREE;
670 if (index == IO_WQ_ACCT_BOUND)
671 worker->flags |= IO_WORKER_F_BOUND;
672 if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND))
673 worker->flags |= IO_WORKER_F_FIXED;
674 acct->nr_workers++;
675 spin_unlock_irq(&wqe->lock);
676
677 if (index == IO_WQ_ACCT_UNBOUND)
678 atomic_inc(&wq->user->processes);
679
680 wake_up_process(worker->task);
681 return true;
682}
683
684static inline bool io_wqe_need_worker(struct io_wqe *wqe, int index)
685 __must_hold(wqe->lock)
686{
687 struct io_wqe_acct *acct = &wqe->acct[index];
688
689
690 if (!hlist_nulls_empty(&wqe->free_list) || !io_wqe_run_queue(wqe))
691 return false;
692 return acct->nr_workers < acct->max_workers;
693}
694
695
696
697
698static int io_wq_manager(void *data)
699{
700 struct io_wq *wq = data;
701 int workers_to_create = num_possible_nodes();
702 int node;
703
704
705 refcount_set(&wq->refs, workers_to_create);
706 for_each_node(node) {
707 if (!node_online(node))
708 continue;
709 if (!create_io_worker(wq, wq->wqes[node], IO_WQ_ACCT_BOUND))
710 goto err;
711 workers_to_create--;
712 }
713
714 while (workers_to_create--)
715 refcount_dec(&wq->refs);
716
717 complete(&wq->done);
718
719 while (!kthread_should_stop()) {
720 if (current->task_works)
721 task_work_run();
722
723 for_each_node(node) {
724 struct io_wqe *wqe = wq->wqes[node];
725 bool fork_worker[2] = { false, false };
726
727 if (!node_online(node))
728 continue;
729
730 spin_lock_irq(&wqe->lock);
731 if (io_wqe_need_worker(wqe, IO_WQ_ACCT_BOUND))
732 fork_worker[IO_WQ_ACCT_BOUND] = true;
733 if (io_wqe_need_worker(wqe, IO_WQ_ACCT_UNBOUND))
734 fork_worker[IO_WQ_ACCT_UNBOUND] = true;
735 spin_unlock_irq(&wqe->lock);
736 if (fork_worker[IO_WQ_ACCT_BOUND])
737 create_io_worker(wq, wqe, IO_WQ_ACCT_BOUND);
738 if (fork_worker[IO_WQ_ACCT_UNBOUND])
739 create_io_worker(wq, wqe, IO_WQ_ACCT_UNBOUND);
740 }
741 set_current_state(TASK_INTERRUPTIBLE);
742 schedule_timeout(HZ);
743 }
744
745 if (current->task_works)
746 task_work_run();
747
748 return 0;
749err:
750 set_bit(IO_WQ_BIT_ERROR, &wq->state);
751 set_bit(IO_WQ_BIT_EXIT, &wq->state);
752 if (refcount_sub_and_test(workers_to_create, &wq->refs))
753 complete(&wq->done);
754 return 0;
755}
756
757static bool io_wq_can_queue(struct io_wqe *wqe, struct io_wqe_acct *acct,
758 struct io_wq_work *work)
759{
760 bool free_worker;
761
762 if (!(work->flags & IO_WQ_WORK_UNBOUND))
763 return true;
764 if (atomic_read(&acct->nr_running))
765 return true;
766
767 rcu_read_lock();
768 free_worker = !hlist_nulls_empty(&wqe->free_list);
769 rcu_read_unlock();
770 if (free_worker)
771 return true;
772
773 if (atomic_read(&wqe->wq->user->processes) >= acct->max_workers &&
774 !(capable(CAP_SYS_RESOURCE) || capable(CAP_SYS_ADMIN)))
775 return false;
776
777 return true;
778}
779
780static void io_run_cancel(struct io_wq_work *work, struct io_wqe *wqe)
781{
782 struct io_wq *wq = wqe->wq;
783
784 do {
785 struct io_wq_work *old_work = work;
786
787 work->flags |= IO_WQ_WORK_CANCEL;
788 work->func(&work);
789 work = (work == old_work) ? NULL : work;
790 wq->free_work(old_work);
791 } while (work);
792}
793
794static void io_wqe_insert_work(struct io_wqe *wqe, struct io_wq_work *work)
795{
796 unsigned int hash;
797 struct io_wq_work *tail;
798
799 if (!io_wq_is_hashed(work)) {
800append:
801 wq_list_add_tail(&work->list, &wqe->work_list);
802 return;
803 }
804
805 hash = io_get_work_hash(work);
806 tail = wqe->hash_tail[hash];
807 wqe->hash_tail[hash] = work;
808 if (!tail)
809 goto append;
810
811 wq_list_add_after(&work->list, &tail->list, &wqe->work_list);
812}
813
814static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
815{
816 struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
817 int work_flags;
818 unsigned long flags;
819
820
821
822
823
824
825
826 if (unlikely(!io_wq_can_queue(wqe, acct, work))) {
827 io_run_cancel(work, wqe);
828 return;
829 }
830
831 work_flags = work->flags;
832 spin_lock_irqsave(&wqe->lock, flags);
833 io_wqe_insert_work(wqe, work);
834 wqe->flags &= ~IO_WQE_FLAG_STALLED;
835 spin_unlock_irqrestore(&wqe->lock, flags);
836
837 if ((work_flags & IO_WQ_WORK_CONCURRENT) ||
838 !atomic_read(&acct->nr_running))
839 io_wqe_wake_worker(wqe, acct);
840}
841
842void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
843{
844 struct io_wqe *wqe = wq->wqes[numa_node_id()];
845
846 io_wqe_enqueue(wqe, work);
847}
848
849
850
851
852
853void io_wq_hash_work(struct io_wq_work *work, void *val)
854{
855 unsigned int bit;
856
857 bit = hash_ptr(val, IO_WQ_HASH_ORDER);
858 work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
859}
860
861static bool io_wqe_worker_send_sig(struct io_worker *worker, void *data)
862{
863 send_sig(SIGINT, worker->task, 1);
864 return false;
865}
866
867
868
869
870
871static bool io_wq_for_each_worker(struct io_wqe *wqe,
872 bool (*func)(struct io_worker *, void *),
873 void *data)
874{
875 struct io_worker *worker;
876 bool ret = false;
877
878 list_for_each_entry_rcu(worker, &wqe->all_list, all_list) {
879 if (io_worker_get(worker)) {
880
881 if (worker->task)
882 ret = func(worker, data);
883 io_worker_release(worker);
884 if (ret)
885 break;
886 }
887 }
888
889 return ret;
890}
891
892void io_wq_cancel_all(struct io_wq *wq)
893{
894 int node;
895
896 set_bit(IO_WQ_BIT_CANCEL, &wq->state);
897
898 rcu_read_lock();
899 for_each_node(node) {
900 struct io_wqe *wqe = wq->wqes[node];
901
902 io_wq_for_each_worker(wqe, io_wqe_worker_send_sig, NULL);
903 }
904 rcu_read_unlock();
905}
906
907struct io_cb_cancel_data {
908 work_cancel_fn *fn;
909 void *data;
910};
911
912static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
913{
914 struct io_cb_cancel_data *match = data;
915 unsigned long flags;
916 bool ret = false;
917
918
919
920
921
922 spin_lock_irqsave(&worker->lock, flags);
923 if (worker->cur_work &&
924 !(worker->cur_work->flags & IO_WQ_WORK_NO_CANCEL) &&
925 match->fn(worker->cur_work, match->data)) {
926 send_sig(SIGINT, worker->task, 1);
927 ret = true;
928 }
929 spin_unlock_irqrestore(&worker->lock, flags);
930
931 return ret;
932}
933
934static enum io_wq_cancel io_wqe_cancel_work(struct io_wqe *wqe,
935 struct io_cb_cancel_data *match)
936{
937 struct io_wq_work_node *node, *prev;
938 struct io_wq_work *work;
939 unsigned long flags;
940 bool found = false;
941
942
943
944
945
946
947 spin_lock_irqsave(&wqe->lock, flags);
948 wq_list_for_each(node, prev, &wqe->work_list) {
949 work = container_of(node, struct io_wq_work, list);
950
951 if (match->fn(work, match->data)) {
952 wq_list_del(&wqe->work_list, node, prev);
953 found = true;
954 break;
955 }
956 }
957 spin_unlock_irqrestore(&wqe->lock, flags);
958
959 if (found) {
960 io_run_cancel(work, wqe);
961 return IO_WQ_CANCEL_OK;
962 }
963
964
965
966
967
968
969
970 rcu_read_lock();
971 found = io_wq_for_each_worker(wqe, io_wq_worker_cancel, match);
972 rcu_read_unlock();
973 return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND;
974}
975
976enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
977 void *data)
978{
979 struct io_cb_cancel_data match = {
980 .fn = cancel,
981 .data = data,
982 };
983 enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
984 int node;
985
986 for_each_node(node) {
987 struct io_wqe *wqe = wq->wqes[node];
988
989 ret = io_wqe_cancel_work(wqe, &match);
990 if (ret != IO_WQ_CANCEL_NOTFOUND)
991 break;
992 }
993
994 return ret;
995}
996
997static bool io_wq_io_cb_cancel_data(struct io_wq_work *work, void *data)
998{
999 return work == data;
1000}
1001
1002enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork)
1003{
1004 return io_wq_cancel_cb(wq, io_wq_io_cb_cancel_data, (void *)cwork);
1005}
1006
1007static bool io_wq_pid_match(struct io_wq_work *work, void *data)
1008{
1009 pid_t pid = (pid_t) (unsigned long) data;
1010
1011 return work->task_pid == pid;
1012}
1013
1014enum io_wq_cancel io_wq_cancel_pid(struct io_wq *wq, pid_t pid)
1015{
1016 void *data = (void *) (unsigned long) pid;
1017
1018 return io_wq_cancel_cb(wq, io_wq_pid_match, data);
1019}
1020
1021struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
1022{
1023 int ret = -ENOMEM, node;
1024 struct io_wq *wq;
1025
1026 if (WARN_ON_ONCE(!data->free_work))
1027 return ERR_PTR(-EINVAL);
1028
1029 wq = kzalloc(sizeof(*wq), GFP_KERNEL);
1030 if (!wq)
1031 return ERR_PTR(-ENOMEM);
1032
1033 wq->wqes = kcalloc(nr_node_ids, sizeof(struct io_wqe *), GFP_KERNEL);
1034 if (!wq->wqes) {
1035 kfree(wq);
1036 return ERR_PTR(-ENOMEM);
1037 }
1038
1039 wq->free_work = data->free_work;
1040
1041
1042 wq->user = data->user;
1043
1044 for_each_node(node) {
1045 struct io_wqe *wqe;
1046 int alloc_node = node;
1047
1048 if (!node_online(alloc_node))
1049 alloc_node = NUMA_NO_NODE;
1050 wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node);
1051 if (!wqe)
1052 goto err;
1053 wq->wqes[node] = wqe;
1054 wqe->node = alloc_node;
1055 wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
1056 atomic_set(&wqe->acct[IO_WQ_ACCT_BOUND].nr_running, 0);
1057 if (wq->user) {
1058 wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
1059 task_rlimit(current, RLIMIT_NPROC);
1060 }
1061 atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0);
1062 wqe->wq = wq;
1063 spin_lock_init(&wqe->lock);
1064 INIT_WQ_LIST(&wqe->work_list);
1065 INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0);
1066 INIT_LIST_HEAD(&wqe->all_list);
1067 }
1068
1069 init_completion(&wq->done);
1070
1071 wq->manager = kthread_create(io_wq_manager, wq, "io_wq_manager");
1072 if (!IS_ERR(wq->manager)) {
1073 wake_up_process(wq->manager);
1074 wait_for_completion(&wq->done);
1075 if (test_bit(IO_WQ_BIT_ERROR, &wq->state)) {
1076 ret = -ENOMEM;
1077 goto err;
1078 }
1079 refcount_set(&wq->use_refs, 1);
1080 reinit_completion(&wq->done);
1081 return wq;
1082 }
1083
1084 ret = PTR_ERR(wq->manager);
1085 complete(&wq->done);
1086err:
1087 for_each_node(node)
1088 kfree(wq->wqes[node]);
1089 kfree(wq->wqes);
1090 kfree(wq);
1091 return ERR_PTR(ret);
1092}
1093
1094bool io_wq_get(struct io_wq *wq, struct io_wq_data *data)
1095{
1096 if (data->free_work != wq->free_work)
1097 return false;
1098
1099 return refcount_inc_not_zero(&wq->use_refs);
1100}
1101
1102static bool io_wq_worker_wake(struct io_worker *worker, void *data)
1103{
1104 wake_up_process(worker->task);
1105 return false;
1106}
1107
1108static void __io_wq_destroy(struct io_wq *wq)
1109{
1110 int node;
1111
1112 set_bit(IO_WQ_BIT_EXIT, &wq->state);
1113 if (wq->manager)
1114 kthread_stop(wq->manager);
1115
1116 rcu_read_lock();
1117 for_each_node(node)
1118 io_wq_for_each_worker(wq->wqes[node], io_wq_worker_wake, NULL);
1119 rcu_read_unlock();
1120
1121 wait_for_completion(&wq->done);
1122
1123 for_each_node(node)
1124 kfree(wq->wqes[node]);
1125 kfree(wq->wqes);
1126 kfree(wq);
1127}
1128
1129void io_wq_destroy(struct io_wq *wq)
1130{
1131 if (refcount_dec_and_test(&wq->use_refs))
1132 __io_wq_destroy(wq);
1133}
1134
1135struct task_struct *io_wq_get_task(struct io_wq *wq)
1136{
1137 return wq->manager;
1138}
1139