1 // SPDX-License-Identifier: GPL-2.0
3 * Basic worker thread pool for io_uring
5 * Copyright (C) 2019 Jens Axboe
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/errno.h>
11 #include <linux/sched/signal.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>
24 #define WORKER_IDLE_TIMEOUT (5 * HZ)
27 IO_WORKER_F_UP = 1, /* up and active */
28 IO_WORKER_F_RUNNING = 2, /* account as running */
29 IO_WORKER_F_FREE = 4, /* worker on free list */
30 IO_WORKER_F_EXITING = 8, /* worker exiting */
31 IO_WORKER_F_FIXED = 16, /* static idle worker */
32 IO_WORKER_F_BOUND = 32, /* is doing bounded work */
36 IO_WQ_BIT_EXIT = 0, /* wq exiting */
37 IO_WQ_BIT_CANCEL = 1, /* cancel work on list */
38 IO_WQ_BIT_ERROR = 2, /* error on setup */
42 IO_WQE_FLAG_STALLED = 1, /* stalled on hash */
46 * One for each thread in a wqe pool
51 struct hlist_nulls_node nulls_node;
52 struct list_head all_list;
53 struct task_struct *task;
56 struct io_wq_work *cur_work;
61 const struct cred *cur_creds;
62 const struct cred *saved_creds;
63 struct files_struct *restore_files;
64 struct fs_struct *restore_fs;
67 #if BITS_PER_LONG == 64
68 #define IO_WQ_HASH_ORDER 6
70 #define IO_WQ_HASH_ORDER 5
73 #define IO_WQ_NR_HASH_BUCKETS (1u << IO_WQ_HASH_ORDER)
87 * Per-node worker thread pool
92 struct io_wq_work_list work_list;
93 unsigned long hash_map;
95 } ____cacheline_aligned_in_smp;
98 struct io_wqe_acct acct[2];
100 struct hlist_nulls_head free_list;
101 struct list_head all_list;
104 struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS];
111 struct io_wqe **wqes;
114 free_work_fn *free_work;
116 struct task_struct *manager;
117 struct user_struct *user;
119 struct completion done;
124 static bool io_worker_get(struct io_worker *worker)
126 return refcount_inc_not_zero(&worker->ref);
129 static void io_worker_release(struct io_worker *worker)
131 if (refcount_dec_and_test(&worker->ref))
132 wake_up_process(worker->task);
136 * Note: drops the wqe->lock if returning true! The caller must re-acquire
137 * the lock in that case. Some callers need to restart handling if this
138 * happens, so we can't just re-acquire the lock on behalf of the caller.
140 static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker)
142 bool dropped_lock = false;
144 if (worker->saved_creds) {
145 revert_creds(worker->saved_creds);
146 worker->cur_creds = worker->saved_creds = NULL;
149 if (current->files != worker->restore_files) {
150 __acquire(&wqe->lock);
151 spin_unlock_irq(&wqe->lock);
155 current->files = worker->restore_files;
156 task_unlock(current);
159 if (current->fs != worker->restore_fs)
160 current->fs = worker->restore_fs;
163 * If we have an active mm, we need to drop the wq lock before unusing
164 * it. If we do, return true and let the caller retry the idle loop.
168 __acquire(&wqe->lock);
169 spin_unlock_irq(&wqe->lock);
172 __set_current_state(TASK_RUNNING);
174 unuse_mm(worker->mm);
182 static inline struct io_wqe_acct *io_work_get_acct(struct io_wqe *wqe,
183 struct io_wq_work *work)
185 if (work->flags & IO_WQ_WORK_UNBOUND)
186 return &wqe->acct[IO_WQ_ACCT_UNBOUND];
188 return &wqe->acct[IO_WQ_ACCT_BOUND];
191 static inline struct io_wqe_acct *io_wqe_get_acct(struct io_wqe *wqe,
192 struct io_worker *worker)
194 if (worker->flags & IO_WORKER_F_BOUND)
195 return &wqe->acct[IO_WQ_ACCT_BOUND];
197 return &wqe->acct[IO_WQ_ACCT_UNBOUND];
200 static void io_worker_exit(struct io_worker *worker)
202 struct io_wqe *wqe = worker->wqe;
203 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
207 * If we're not at zero, someone else is holding a brief reference
208 * to the worker. Wait for that to go away.
210 set_current_state(TASK_INTERRUPTIBLE);
211 if (!refcount_dec_and_test(&worker->ref))
213 __set_current_state(TASK_RUNNING);
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);
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);
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);
236 /* all workers gone, wq exit can proceed */
237 if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs))
238 complete(&wqe->wq->done);
240 kfree_rcu(worker, rcu);
243 static inline bool io_wqe_run_queue(struct io_wqe *wqe)
244 __must_hold(wqe->lock)
246 if (!wq_list_empty(&wqe->work_list) &&
247 !(wqe->flags & IO_WQE_FLAG_STALLED))
253 * Check head of free list for an available worker. If one isn't available,
254 * caller must wake up the wq manager to create one.
256 static bool io_wqe_activate_free_worker(struct io_wqe *wqe)
259 struct hlist_nulls_node *n;
260 struct io_worker *worker;
262 n = rcu_dereference(hlist_nulls_first_rcu(&wqe->free_list));
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);
277 * We need a worker. If we find a free one, we're good. If not, and we're
278 * below the max number of workers, wake up the manager to create one.
280 static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
285 * Most likely an attempt to queue unbounded work on an io_wq that
286 * wasn't setup with any unbounded workers.
288 WARN_ON_ONCE(!acct->max_workers);
291 ret = io_wqe_activate_free_worker(wqe);
294 if (!ret && acct->nr_workers < acct->max_workers)
295 wake_up_process(wqe->wq->manager);
298 static void io_wqe_inc_running(struct io_wqe *wqe, struct io_worker *worker)
300 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
302 atomic_inc(&acct->nr_running);
305 static void io_wqe_dec_running(struct io_wqe *wqe, struct io_worker *worker)
306 __must_hold(wqe->lock)
308 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
310 if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe))
311 io_wqe_wake_worker(wqe, acct);
314 static void io_worker_start(struct io_wqe *wqe, struct io_worker *worker)
316 allow_kernel_signal(SIGINT);
318 current->flags |= PF_IO_WORKER;
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);
327 * Worker will start processing some work. Move it to the busy list, if
328 * it's currently on the freelist
330 static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
331 struct io_wq_work *work)
332 __must_hold(wqe->lock)
334 bool worker_bound, work_bound;
336 if (worker->flags & IO_WORKER_F_FREE) {
337 worker->flags &= ~IO_WORKER_F_FREE;
338 hlist_nulls_del_init_rcu(&worker->nulls_node);
342 * If worker is moving from bound to unbound (or vice versa), then
343 * ensure we update the running accounting.
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);
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);
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);
360 io_wqe_inc_running(wqe, worker);
365 * No work, worker going to sleep. Move to freelist, and unuse mm if we
366 * have one attached. Dropping the mm may potentially sleep, so we drop
367 * the lock in that case and return success. Since the caller has to
368 * retry the loop in that case (we changed task state), we don't regrab
369 * the lock if we return success.
371 static bool __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker)
372 __must_hold(wqe->lock)
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);
379 return __io_worker_unuse(wqe, worker);
382 static inline unsigned int io_get_work_hash(struct io_wq_work *work)
384 return work->flags >> IO_WQ_HASH_SHIFT;
387 static struct io_wq_work *io_get_next_work(struct io_wqe *wqe)
388 __must_hold(wqe->lock)
390 struct io_wq_work_node *node, *prev;
391 struct io_wq_work *work, *tail;
394 wq_list_for_each(node, prev, &wqe->work_list) {
395 work = container_of(node, struct io_wq_work, list);
397 /* not hashed, can run anytime */
398 if (!io_wq_is_hashed(work)) {
399 wq_list_del(&wqe->work_list, node, prev);
403 /* hashed, can run if not already running */
404 hash = io_get_work_hash(work);
405 if (!(wqe->hash_map & BIT(hash))) {
406 wqe->hash_map |= BIT(hash);
407 /* all items with this hash lie in [work, tail] */
408 tail = wqe->hash_tail[hash];
409 wqe->hash_tail[hash] = NULL;
410 wq_list_cut(&wqe->work_list, &tail->list, prev);
418 static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work)
421 unuse_mm(worker->mm);
429 if (mmget_not_zero(work->mm)) {
433 worker->mm = work->mm;
434 /* hang on to this mm */
439 /* failed grabbing mm, ensure work gets cancelled */
440 work->flags |= IO_WQ_WORK_CANCEL;
443 static void io_wq_switch_creds(struct io_worker *worker,
444 struct io_wq_work *work)
446 const struct cred *old_creds = override_creds(work->creds);
448 worker->cur_creds = work->creds;
449 if (worker->saved_creds)
450 put_cred(old_creds); /* creds set by previous switch */
452 worker->saved_creds = old_creds;
455 static void io_impersonate_work(struct io_worker *worker,
456 struct io_wq_work *work)
458 if (work->files && current->files != work->files) {
460 current->files = work->files;
461 task_unlock(current);
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);
471 static void io_assign_current_work(struct io_worker *worker,
472 struct io_wq_work *work)
475 /* flush pending signals before assigning new work */
476 if (signal_pending(current))
477 flush_signals(current);
481 spin_lock_irq(&worker->lock);
482 worker->cur_work = work;
483 spin_unlock_irq(&worker->lock);
486 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work);
488 static void io_worker_handle_work(struct io_worker *worker)
489 __releases(wqe->lock)
491 struct io_wqe *wqe = worker->wqe;
492 struct io_wq *wq = wqe->wq;
495 struct io_wq_work *work;
499 * If we got some work, mark us as busy. If we didn't, but
500 * the list isn't empty, it means we stalled on hashed work.
501 * Mark us stalled so we don't keep looking for work when we
502 * can't make progress, any work completion or insertion will
503 * clear the stalled flag.
505 work = io_get_next_work(wqe);
507 __io_worker_busy(wqe, worker, work);
508 else if (!wq_list_empty(&wqe->work_list))
509 wqe->flags |= IO_WQE_FLAG_STALLED;
511 spin_unlock_irq(&wqe->lock);
514 io_assign_current_work(worker, work);
516 /* handle a whole dependent link */
518 struct io_wq_work *old_work, *next_hashed, *linked;
520 next_hashed = wq_next_work(work);
521 io_impersonate_work(worker, work);
523 * OK to set IO_WQ_WORK_CANCEL even for uncancellable
524 * work, the worker function will do the right thing.
526 if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
527 work->flags |= IO_WQ_WORK_CANCEL;
529 hash = io_get_work_hash(work);
530 linked = old_work = work;
531 linked->func(&linked);
532 linked = (old_work == linked) ? NULL : linked;
535 if (!work && linked && !io_wq_is_hashed(linked)) {
539 io_assign_current_work(worker, work);
540 wq->free_work(old_work);
543 io_wqe_enqueue(wqe, linked);
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 /* dependent work is not hashed */
551 /* skip unnecessary unlock-lock wqe->lock */
554 spin_unlock_irq(&wqe->lock);
558 spin_lock_irq(&wqe->lock);
562 static int io_wqe_worker(void *data)
564 struct io_worker *worker = data;
565 struct io_wqe *wqe = worker->wqe;
566 struct io_wq *wq = wqe->wq;
568 io_worker_start(wqe, worker);
570 while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
571 set_current_state(TASK_INTERRUPTIBLE);
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);
579 /* drops the lock on success, retry */
580 if (__io_worker_idle(wqe, worker)) {
581 __release(&wqe->lock);
584 spin_unlock_irq(&wqe->lock);
585 if (signal_pending(current))
586 flush_signals(current);
587 if (schedule_timeout(WORKER_IDLE_TIMEOUT))
589 /* timed out, exit unless we're the fixed worker */
590 if (test_bit(IO_WQ_BIT_EXIT, &wq->state) ||
591 !(worker->flags & IO_WORKER_F_FIXED))
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);
600 spin_unlock_irq(&wqe->lock);
603 io_worker_exit(worker);
608 * Called when a worker is scheduled in. Mark us as currently running.
610 void io_wq_worker_running(struct task_struct *tsk)
612 struct io_worker *worker = kthread_data(tsk);
613 struct io_wqe *wqe = worker->wqe;
615 if (!(worker->flags & IO_WORKER_F_UP))
617 if (worker->flags & IO_WORKER_F_RUNNING)
619 worker->flags |= IO_WORKER_F_RUNNING;
620 io_wqe_inc_running(wqe, worker);
624 * Called when worker is going to sleep. If there are no workers currently
625 * running and we have work pending, wake up a free one or have the manager
628 void io_wq_worker_sleeping(struct task_struct *tsk)
630 struct io_worker *worker = kthread_data(tsk);
631 struct io_wqe *wqe = worker->wqe;
633 if (!(worker->flags & IO_WORKER_F_UP))
635 if (!(worker->flags & IO_WORKER_F_RUNNING))
638 worker->flags &= ~IO_WORKER_F_RUNNING;
640 spin_lock_irq(&wqe->lock);
641 io_wqe_dec_running(wqe, worker);
642 spin_unlock_irq(&wqe->lock);
645 static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
647 struct io_wqe_acct *acct =&wqe->acct[index];
648 struct io_worker *worker;
650 worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, wqe->node);
654 refcount_set(&worker->ref, 1);
655 worker->nulls_node.pprev = NULL;
657 spin_lock_init(&worker->lock);
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)) {
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;
675 spin_unlock_irq(&wqe->lock);
677 if (index == IO_WQ_ACCT_UNBOUND)
678 atomic_inc(&wq->user->processes);
680 wake_up_process(worker->task);
684 static inline bool io_wqe_need_worker(struct io_wqe *wqe, int index)
685 __must_hold(wqe->lock)
687 struct io_wqe_acct *acct = &wqe->acct[index];
689 /* if we have available workers or no work, no need */
690 if (!hlist_nulls_empty(&wqe->free_list) || !io_wqe_run_queue(wqe))
692 return acct->nr_workers < acct->max_workers;
696 * Manager thread. Tasked with creating new workers, if we need them.
698 static int io_wq_manager(void *data)
700 struct io_wq *wq = data;
701 int workers_to_create = num_possible_nodes();
704 /* create fixed workers */
705 refcount_set(&wq->refs, workers_to_create);
706 for_each_node(node) {
707 if (!node_online(node))
709 if (!create_io_worker(wq, wq->wqes[node], IO_WQ_ACCT_BOUND))
714 while (workers_to_create--)
715 refcount_dec(&wq->refs);
719 while (!kthread_should_stop()) {
720 if (current->task_works)
723 for_each_node(node) {
724 struct io_wqe *wqe = wq->wqes[node];
725 bool fork_worker[2] = { false, false };
727 if (!node_online(node))
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);
741 set_current_state(TASK_INTERRUPTIBLE);
742 schedule_timeout(HZ);
745 if (current->task_works)
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))
757 static bool io_wq_can_queue(struct io_wqe *wqe, struct io_wqe_acct *acct,
758 struct io_wq_work *work)
762 if (!(work->flags & IO_WQ_WORK_UNBOUND))
764 if (atomic_read(&acct->nr_running))
768 free_worker = !hlist_nulls_empty(&wqe->free_list);
773 if (atomic_read(&wqe->wq->user->processes) >= acct->max_workers &&
774 !(capable(CAP_SYS_RESOURCE) || capable(CAP_SYS_ADMIN)))
780 static void io_run_cancel(struct io_wq_work *work, struct io_wqe *wqe)
782 struct io_wq *wq = wqe->wq;
785 struct io_wq_work *old_work = work;
787 work->flags |= IO_WQ_WORK_CANCEL;
789 work = (work == old_work) ? NULL : work;
790 wq->free_work(old_work);
794 static void io_wqe_insert_work(struct io_wqe *wqe, struct io_wq_work *work)
797 struct io_wq_work *tail;
799 if (!io_wq_is_hashed(work)) {
801 wq_list_add_tail(&work->list, &wqe->work_list);
805 hash = io_get_work_hash(work);
806 tail = wqe->hash_tail[hash];
807 wqe->hash_tail[hash] = work;
811 wq_list_add_after(&work->list, &tail->list, &wqe->work_list);
814 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
816 struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
821 * Do early check to see if we need a new unbound worker, and if we do,
822 * if we're allowed to do so. This isn't 100% accurate as there's a
823 * gap between this check and incrementing the value, but that's OK.
824 * It's close enough to not be an issue, fork() has the same delay.
826 if (unlikely(!io_wq_can_queue(wqe, acct, work))) {
827 io_run_cancel(work, wqe);
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);
837 if ((work_flags & IO_WQ_WORK_CONCURRENT) ||
838 !atomic_read(&acct->nr_running))
839 io_wqe_wake_worker(wqe, acct);
842 void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
844 struct io_wqe *wqe = wq->wqes[numa_node_id()];
846 io_wqe_enqueue(wqe, work);
850 * Work items that hash to the same value will not be done in parallel.
851 * Used to limit concurrent writes, generally hashed by inode.
853 void io_wq_hash_work(struct io_wq_work *work, void *val)
857 bit = hash_ptr(val, IO_WQ_HASH_ORDER);
858 work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
861 static bool io_wqe_worker_send_sig(struct io_worker *worker, void *data)
863 send_sig(SIGINT, worker->task, 1);
868 * Iterate the passed in list and call the specific function for each
869 * worker that isn't exiting
871 static bool io_wq_for_each_worker(struct io_wqe *wqe,
872 bool (*func)(struct io_worker *, void *),
875 struct io_worker *worker;
878 list_for_each_entry_rcu(worker, &wqe->all_list, all_list) {
879 if (io_worker_get(worker)) {
880 /* no task if node is/was offline */
882 ret = func(worker, data);
883 io_worker_release(worker);
892 void io_wq_cancel_all(struct io_wq *wq)
896 set_bit(IO_WQ_BIT_CANCEL, &wq->state);
899 for_each_node(node) {
900 struct io_wqe *wqe = wq->wqes[node];
902 io_wq_for_each_worker(wqe, io_wqe_worker_send_sig, NULL);
907 struct io_cb_cancel_data {
912 static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
914 struct io_cb_cancel_data *match = data;
919 * Hold the lock to avoid ->cur_work going out of scope, caller
920 * may dereference the passed in work.
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);
929 spin_unlock_irqrestore(&worker->lock, flags);
934 static enum io_wq_cancel io_wqe_cancel_work(struct io_wqe *wqe,
935 struct io_cb_cancel_data *match)
937 struct io_wq_work_node *node, *prev;
938 struct io_wq_work *work;
943 * First check pending list, if we're lucky we can just remove it
944 * from there. CANCEL_OK means that the work is returned as-new,
945 * no completion will be posted for it.
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);
951 if (match->fn(work, match->data)) {
952 wq_list_del(&wqe->work_list, node, prev);
957 spin_unlock_irqrestore(&wqe->lock, flags);
960 io_run_cancel(work, wqe);
961 return IO_WQ_CANCEL_OK;
965 * Now check if a free (going busy) or busy worker has the work
966 * currently running. If we find it there, we'll return CANCEL_RUNNING
967 * as an indication that we attempt to signal cancellation. The
968 * completion will run normally in this case.
971 found = io_wq_for_each_worker(wqe, io_wq_worker_cancel, match);
973 return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND;
976 enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
979 struct io_cb_cancel_data match = {
983 enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
986 for_each_node(node) {
987 struct io_wqe *wqe = wq->wqes[node];
989 ret = io_wqe_cancel_work(wqe, &match);
990 if (ret != IO_WQ_CANCEL_NOTFOUND)
997 static bool io_wq_io_cb_cancel_data(struct io_wq_work *work, void *data)
1002 enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork)
1004 return io_wq_cancel_cb(wq, io_wq_io_cb_cancel_data, (void *)cwork);
1007 static bool io_wq_pid_match(struct io_wq_work *work, void *data)
1009 pid_t pid = (pid_t) (unsigned long) data;
1011 return work->task_pid == pid;
1014 enum io_wq_cancel io_wq_cancel_pid(struct io_wq *wq, pid_t pid)
1016 void *data = (void *) (unsigned long) pid;
1018 return io_wq_cancel_cb(wq, io_wq_pid_match, data);
1021 struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
1023 int ret = -ENOMEM, node;
1026 if (WARN_ON_ONCE(!data->free_work))
1027 return ERR_PTR(-EINVAL);
1029 wq = kzalloc(sizeof(*wq), GFP_KERNEL);
1031 return ERR_PTR(-ENOMEM);
1033 wq->wqes = kcalloc(nr_node_ids, sizeof(struct io_wqe *), GFP_KERNEL);
1036 return ERR_PTR(-ENOMEM);
1039 wq->free_work = data->free_work;
1041 /* caller must already hold a reference to this */
1042 wq->user = data->user;
1044 for_each_node(node) {
1046 int alloc_node = node;
1048 if (!node_online(alloc_node))
1049 alloc_node = NUMA_NO_NODE;
1050 wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node);
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);
1058 wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
1059 task_rlimit(current, RLIMIT_NPROC);
1061 atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0);
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);
1069 init_completion(&wq->done);
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)) {
1079 refcount_set(&wq->use_refs, 1);
1080 reinit_completion(&wq->done);
1084 ret = PTR_ERR(wq->manager);
1085 complete(&wq->done);
1088 kfree(wq->wqes[node]);
1091 return ERR_PTR(ret);
1094 bool io_wq_get(struct io_wq *wq, struct io_wq_data *data)
1096 if (data->free_work != wq->free_work)
1099 return refcount_inc_not_zero(&wq->use_refs);
1102 static bool io_wq_worker_wake(struct io_worker *worker, void *data)
1104 wake_up_process(worker->task);
1108 static void __io_wq_destroy(struct io_wq *wq)
1112 set_bit(IO_WQ_BIT_EXIT, &wq->state);
1114 kthread_stop(wq->manager);
1118 io_wq_for_each_worker(wq->wqes[node], io_wq_worker_wake, NULL);
1121 wait_for_completion(&wq->done);
1124 kfree(wq->wqes[node]);
1129 void io_wq_destroy(struct io_wq *wq)
1131 if (refcount_dec_and_test(&wq->use_refs))
1132 __io_wq_destroy(wq);
1135 struct task_struct *io_wq_get_task(struct io_wq *wq)