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>
23 #define WORKER_IDLE_TIMEOUT (5 * HZ)
26 IO_WORKER_F_UP = 1, /* up and active */
27 IO_WORKER_F_RUNNING = 2, /* account as running */
28 IO_WORKER_F_FREE = 4, /* worker on free list */
29 IO_WORKER_F_EXITING = 8, /* worker exiting */
30 IO_WORKER_F_FIXED = 16, /* static idle worker */
31 IO_WORKER_F_BOUND = 32, /* is doing bounded work */
35 IO_WQ_BIT_EXIT = 0, /* wq exiting */
36 IO_WQ_BIT_CANCEL = 1, /* cancel work on list */
37 IO_WQ_BIT_ERROR = 2, /* error on setup */
41 IO_WQE_FLAG_STALLED = 1, /* stalled on hash */
45 * One for each thread in a wqe pool
50 struct hlist_nulls_node nulls_node;
51 struct list_head all_list;
52 struct task_struct *task;
55 struct io_wq_work *cur_work;
60 const struct cred *cur_creds;
61 const struct cred *saved_creds;
62 struct files_struct *restore_files;
63 struct fs_struct *restore_fs;
66 #if BITS_PER_LONG == 64
67 #define IO_WQ_HASH_ORDER 6
69 #define IO_WQ_HASH_ORDER 5
84 * Per-node worker thread pool
89 struct io_wq_work_list work_list;
90 unsigned long hash_map;
92 } ____cacheline_aligned_in_smp;
95 struct io_wqe_acct acct[2];
97 struct hlist_nulls_head free_list;
98 struct list_head all_list;
107 struct io_wqe **wqes;
110 get_work_fn *get_work;
111 put_work_fn *put_work;
113 struct task_struct *manager;
114 struct user_struct *user;
116 struct completion done;
121 static bool io_worker_get(struct io_worker *worker)
123 return refcount_inc_not_zero(&worker->ref);
126 static void io_worker_release(struct io_worker *worker)
128 if (refcount_dec_and_test(&worker->ref))
129 wake_up_process(worker->task);
133 * Note: drops the wqe->lock if returning true! The caller must re-acquire
134 * the lock in that case. Some callers need to restart handling if this
135 * happens, so we can't just re-acquire the lock on behalf of the caller.
137 static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker)
139 bool dropped_lock = false;
141 if (worker->saved_creds) {
142 revert_creds(worker->saved_creds);
143 worker->cur_creds = worker->saved_creds = NULL;
146 if (current->files != worker->restore_files) {
147 __acquire(&wqe->lock);
148 spin_unlock_irq(&wqe->lock);
152 current->files = worker->restore_files;
153 task_unlock(current);
156 if (current->fs != worker->restore_fs)
157 current->fs = worker->restore_fs;
160 * If we have an active mm, we need to drop the wq lock before unusing
161 * it. If we do, return true and let the caller retry the idle loop.
165 __acquire(&wqe->lock);
166 spin_unlock_irq(&wqe->lock);
169 __set_current_state(TASK_RUNNING);
171 unuse_mm(worker->mm);
179 static inline struct io_wqe_acct *io_work_get_acct(struct io_wqe *wqe,
180 struct io_wq_work *work)
182 if (work->flags & IO_WQ_WORK_UNBOUND)
183 return &wqe->acct[IO_WQ_ACCT_UNBOUND];
185 return &wqe->acct[IO_WQ_ACCT_BOUND];
188 static inline struct io_wqe_acct *io_wqe_get_acct(struct io_wqe *wqe,
189 struct io_worker *worker)
191 if (worker->flags & IO_WORKER_F_BOUND)
192 return &wqe->acct[IO_WQ_ACCT_BOUND];
194 return &wqe->acct[IO_WQ_ACCT_UNBOUND];
197 static void io_worker_exit(struct io_worker *worker)
199 struct io_wqe *wqe = worker->wqe;
200 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
204 * If we're not at zero, someone else is holding a brief reference
205 * to the worker. Wait for that to go away.
207 set_current_state(TASK_INTERRUPTIBLE);
208 if (!refcount_dec_and_test(&worker->ref))
210 __set_current_state(TASK_RUNNING);
213 current->flags &= ~PF_IO_WORKER;
214 if (worker->flags & IO_WORKER_F_RUNNING)
215 atomic_dec(&acct->nr_running);
216 if (!(worker->flags & IO_WORKER_F_BOUND))
217 atomic_dec(&wqe->wq->user->processes);
221 spin_lock_irq(&wqe->lock);
222 hlist_nulls_del_rcu(&worker->nulls_node);
223 list_del_rcu(&worker->all_list);
224 if (__io_worker_unuse(wqe, worker)) {
225 __release(&wqe->lock);
226 spin_lock_irq(&wqe->lock);
229 nr_workers = wqe->acct[IO_WQ_ACCT_BOUND].nr_workers +
230 wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers;
231 spin_unlock_irq(&wqe->lock);
233 /* all workers gone, wq exit can proceed */
234 if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs))
235 complete(&wqe->wq->done);
237 kfree_rcu(worker, rcu);
240 static inline bool io_wqe_run_queue(struct io_wqe *wqe)
241 __must_hold(wqe->lock)
243 if (!wq_list_empty(&wqe->work_list) &&
244 !(wqe->flags & IO_WQE_FLAG_STALLED))
250 * Check head of free list for an available worker. If one isn't available,
251 * caller must wake up the wq manager to create one.
253 static bool io_wqe_activate_free_worker(struct io_wqe *wqe)
256 struct hlist_nulls_node *n;
257 struct io_worker *worker;
259 n = rcu_dereference(hlist_nulls_first_rcu(&wqe->free_list));
263 worker = hlist_nulls_entry(n, struct io_worker, nulls_node);
264 if (io_worker_get(worker)) {
265 wake_up_process(worker->task);
266 io_worker_release(worker);
274 * We need a worker. If we find a free one, we're good. If not, and we're
275 * below the max number of workers, wake up the manager to create one.
277 static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
282 * Most likely an attempt to queue unbounded work on an io_wq that
283 * wasn't setup with any unbounded workers.
285 WARN_ON_ONCE(!acct->max_workers);
288 ret = io_wqe_activate_free_worker(wqe);
291 if (!ret && acct->nr_workers < acct->max_workers)
292 wake_up_process(wqe->wq->manager);
295 static void io_wqe_inc_running(struct io_wqe *wqe, struct io_worker *worker)
297 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
299 atomic_inc(&acct->nr_running);
302 static void io_wqe_dec_running(struct io_wqe *wqe, struct io_worker *worker)
303 __must_hold(wqe->lock)
305 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
307 if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe))
308 io_wqe_wake_worker(wqe, acct);
311 static void io_worker_start(struct io_wqe *wqe, struct io_worker *worker)
313 allow_kernel_signal(SIGINT);
315 current->flags |= PF_IO_WORKER;
317 worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
318 worker->restore_files = current->files;
319 worker->restore_fs = current->fs;
320 io_wqe_inc_running(wqe, worker);
324 * Worker will start processing some work. Move it to the busy list, if
325 * it's currently on the freelist
327 static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
328 struct io_wq_work *work)
329 __must_hold(wqe->lock)
331 bool worker_bound, work_bound;
333 if (worker->flags & IO_WORKER_F_FREE) {
334 worker->flags &= ~IO_WORKER_F_FREE;
335 hlist_nulls_del_init_rcu(&worker->nulls_node);
339 * If worker is moving from bound to unbound (or vice versa), then
340 * ensure we update the running accounting.
342 worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
343 work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
344 if (worker_bound != work_bound) {
345 io_wqe_dec_running(wqe, worker);
347 worker->flags |= IO_WORKER_F_BOUND;
348 wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
349 wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
350 atomic_dec(&wqe->wq->user->processes);
352 worker->flags &= ~IO_WORKER_F_BOUND;
353 wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
354 wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
355 atomic_inc(&wqe->wq->user->processes);
357 io_wqe_inc_running(wqe, worker);
362 * No work, worker going to sleep. Move to freelist, and unuse mm if we
363 * have one attached. Dropping the mm may potentially sleep, so we drop
364 * the lock in that case and return success. Since the caller has to
365 * retry the loop in that case (we changed task state), we don't regrab
366 * the lock if we return success.
368 static bool __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker)
369 __must_hold(wqe->lock)
371 if (!(worker->flags & IO_WORKER_F_FREE)) {
372 worker->flags |= IO_WORKER_F_FREE;
373 hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
376 return __io_worker_unuse(wqe, worker);
379 static struct io_wq_work *io_get_next_work(struct io_wqe *wqe, unsigned *hash)
380 __must_hold(wqe->lock)
382 struct io_wq_work_node *node, *prev;
383 struct io_wq_work *work;
385 wq_list_for_each(node, prev, &wqe->work_list) {
386 work = container_of(node, struct io_wq_work, list);
388 /* not hashed, can run anytime */
389 if (!(work->flags & IO_WQ_WORK_HASHED)) {
390 wq_node_del(&wqe->work_list, node, prev);
394 /* hashed, can run if not already running */
395 *hash = work->flags >> IO_WQ_HASH_SHIFT;
396 if (!(wqe->hash_map & BIT_ULL(*hash))) {
397 wqe->hash_map |= BIT_ULL(*hash);
398 wq_node_del(&wqe->work_list, node, prev);
406 static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work)
409 unuse_mm(worker->mm);
417 if (mmget_not_zero(work->mm)) {
421 worker->mm = work->mm;
422 /* hang on to this mm */
427 /* failed grabbing mm, ensure work gets cancelled */
428 work->flags |= IO_WQ_WORK_CANCEL;
431 static void io_wq_switch_creds(struct io_worker *worker,
432 struct io_wq_work *work)
434 const struct cred *old_creds = override_creds(work->creds);
436 worker->cur_creds = work->creds;
437 if (worker->saved_creds)
438 put_cred(old_creds); /* creds set by previous switch */
440 worker->saved_creds = old_creds;
443 static void io_worker_handle_work(struct io_worker *worker)
444 __releases(wqe->lock)
446 struct io_wq_work *work, *old_work = NULL, *put_work = NULL;
447 struct io_wqe *wqe = worker->wqe;
448 struct io_wq *wq = wqe->wq;
454 * If we got some work, mark us as busy. If we didn't, but
455 * the list isn't empty, it means we stalled on hashed work.
456 * Mark us stalled so we don't keep looking for work when we
457 * can't make progress, any work completion or insertion will
458 * clear the stalled flag.
460 work = io_get_next_work(wqe, &hash);
462 __io_worker_busy(wqe, worker, work);
463 else if (!wq_list_empty(&wqe->work_list))
464 wqe->flags |= IO_WQE_FLAG_STALLED;
466 spin_unlock_irq(&wqe->lock);
467 if (put_work && wq->put_work)
468 wq->put_work(old_work);
472 /* flush any pending signals before assigning new work */
473 if (signal_pending(current))
474 flush_signals(current);
478 spin_lock_irq(&worker->lock);
479 worker->cur_work = work;
480 spin_unlock_irq(&worker->lock);
482 if (work->flags & IO_WQ_WORK_CB)
485 if (work->files && current->files != work->files) {
487 current->files = work->files;
488 task_unlock(current);
490 if (work->fs && current->fs != work->fs)
491 current->fs = work->fs;
492 if (work->mm != worker->mm)
493 io_wq_switch_mm(worker, work);
494 if (worker->cur_creds != work->creds)
495 io_wq_switch_creds(worker, work);
497 * OK to set IO_WQ_WORK_CANCEL even for uncancellable work,
498 * the worker function will do the right thing.
500 if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
501 work->flags |= IO_WQ_WORK_CANCEL;
503 work->flags |= IO_WQ_WORK_HAS_MM;
513 spin_lock_irq(&worker->lock);
514 worker->cur_work = NULL;
515 spin_unlock_irq(&worker->lock);
517 spin_lock_irq(&wqe->lock);
520 wqe->hash_map &= ~BIT_ULL(hash);
521 wqe->flags &= ~IO_WQE_FLAG_STALLED;
523 if (work && work != old_work) {
524 spin_unlock_irq(&wqe->lock);
526 if (put_work && wq->put_work) {
527 wq->put_work(put_work);
531 /* dependent work not hashed */
538 static int io_wqe_worker(void *data)
540 struct io_worker *worker = data;
541 struct io_wqe *wqe = worker->wqe;
542 struct io_wq *wq = wqe->wq;
544 io_worker_start(wqe, worker);
546 while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
547 set_current_state(TASK_INTERRUPTIBLE);
549 spin_lock_irq(&wqe->lock);
550 if (io_wqe_run_queue(wqe)) {
551 __set_current_state(TASK_RUNNING);
552 io_worker_handle_work(worker);
555 /* drops the lock on success, retry */
556 if (__io_worker_idle(wqe, worker)) {
557 __release(&wqe->lock);
560 spin_unlock_irq(&wqe->lock);
561 if (signal_pending(current))
562 flush_signals(current);
563 if (schedule_timeout(WORKER_IDLE_TIMEOUT))
565 /* timed out, exit unless we're the fixed worker */
566 if (test_bit(IO_WQ_BIT_EXIT, &wq->state) ||
567 !(worker->flags & IO_WORKER_F_FIXED))
571 if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
572 spin_lock_irq(&wqe->lock);
573 if (!wq_list_empty(&wqe->work_list))
574 io_worker_handle_work(worker);
576 spin_unlock_irq(&wqe->lock);
579 io_worker_exit(worker);
584 * Called when a worker is scheduled in. Mark us as currently running.
586 void io_wq_worker_running(struct task_struct *tsk)
588 struct io_worker *worker = kthread_data(tsk);
589 struct io_wqe *wqe = worker->wqe;
591 if (!(worker->flags & IO_WORKER_F_UP))
593 if (worker->flags & IO_WORKER_F_RUNNING)
595 worker->flags |= IO_WORKER_F_RUNNING;
596 io_wqe_inc_running(wqe, worker);
600 * Called when worker is going to sleep. If there are no workers currently
601 * running and we have work pending, wake up a free one or have the manager
604 void io_wq_worker_sleeping(struct task_struct *tsk)
606 struct io_worker *worker = kthread_data(tsk);
607 struct io_wqe *wqe = worker->wqe;
609 if (!(worker->flags & IO_WORKER_F_UP))
611 if (!(worker->flags & IO_WORKER_F_RUNNING))
614 worker->flags &= ~IO_WORKER_F_RUNNING;
616 spin_lock_irq(&wqe->lock);
617 io_wqe_dec_running(wqe, worker);
618 spin_unlock_irq(&wqe->lock);
621 static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
623 struct io_wqe_acct *acct =&wqe->acct[index];
624 struct io_worker *worker;
626 worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, wqe->node);
630 refcount_set(&worker->ref, 1);
631 worker->nulls_node.pprev = NULL;
633 spin_lock_init(&worker->lock);
635 worker->task = kthread_create_on_node(io_wqe_worker, worker, wqe->node,
636 "io_wqe_worker-%d/%d", index, wqe->node);
637 if (IS_ERR(worker->task)) {
642 spin_lock_irq(&wqe->lock);
643 hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
644 list_add_tail_rcu(&worker->all_list, &wqe->all_list);
645 worker->flags |= IO_WORKER_F_FREE;
646 if (index == IO_WQ_ACCT_BOUND)
647 worker->flags |= IO_WORKER_F_BOUND;
648 if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND))
649 worker->flags |= IO_WORKER_F_FIXED;
651 spin_unlock_irq(&wqe->lock);
653 if (index == IO_WQ_ACCT_UNBOUND)
654 atomic_inc(&wq->user->processes);
656 wake_up_process(worker->task);
660 static inline bool io_wqe_need_worker(struct io_wqe *wqe, int index)
661 __must_hold(wqe->lock)
663 struct io_wqe_acct *acct = &wqe->acct[index];
665 /* if we have available workers or no work, no need */
666 if (!hlist_nulls_empty(&wqe->free_list) || !io_wqe_run_queue(wqe))
668 return acct->nr_workers < acct->max_workers;
672 * Manager thread. Tasked with creating new workers, if we need them.
674 static int io_wq_manager(void *data)
676 struct io_wq *wq = data;
677 int workers_to_create = num_possible_nodes();
680 /* create fixed workers */
681 refcount_set(&wq->refs, workers_to_create);
682 for_each_node(node) {
683 if (!node_online(node))
685 if (!create_io_worker(wq, wq->wqes[node], IO_WQ_ACCT_BOUND))
690 while (workers_to_create--)
691 refcount_dec(&wq->refs);
695 while (!kthread_should_stop()) {
696 for_each_node(node) {
697 struct io_wqe *wqe = wq->wqes[node];
698 bool fork_worker[2] = { false, false };
700 if (!node_online(node))
703 spin_lock_irq(&wqe->lock);
704 if (io_wqe_need_worker(wqe, IO_WQ_ACCT_BOUND))
705 fork_worker[IO_WQ_ACCT_BOUND] = true;
706 if (io_wqe_need_worker(wqe, IO_WQ_ACCT_UNBOUND))
707 fork_worker[IO_WQ_ACCT_UNBOUND] = true;
708 spin_unlock_irq(&wqe->lock);
709 if (fork_worker[IO_WQ_ACCT_BOUND])
710 create_io_worker(wq, wqe, IO_WQ_ACCT_BOUND);
711 if (fork_worker[IO_WQ_ACCT_UNBOUND])
712 create_io_worker(wq, wqe, IO_WQ_ACCT_UNBOUND);
714 set_current_state(TASK_INTERRUPTIBLE);
715 schedule_timeout(HZ);
720 set_bit(IO_WQ_BIT_ERROR, &wq->state);
721 set_bit(IO_WQ_BIT_EXIT, &wq->state);
722 if (refcount_sub_and_test(workers_to_create, &wq->refs))
727 static bool io_wq_can_queue(struct io_wqe *wqe, struct io_wqe_acct *acct,
728 struct io_wq_work *work)
732 if (!(work->flags & IO_WQ_WORK_UNBOUND))
734 if (atomic_read(&acct->nr_running))
738 free_worker = !hlist_nulls_empty(&wqe->free_list);
743 if (atomic_read(&wqe->wq->user->processes) >= acct->max_workers &&
744 !(capable(CAP_SYS_RESOURCE) || capable(CAP_SYS_ADMIN)))
750 static void io_run_cancel(struct io_wq_work *work)
753 struct io_wq_work *old_work = work;
755 work->flags |= IO_WQ_WORK_CANCEL;
757 work = (work == old_work) ? NULL : work;
761 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
763 struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
768 * Do early check to see if we need a new unbound worker, and if we do,
769 * if we're allowed to do so. This isn't 100% accurate as there's a
770 * gap between this check and incrementing the value, but that's OK.
771 * It's close enough to not be an issue, fork() has the same delay.
773 if (unlikely(!io_wq_can_queue(wqe, acct, work))) {
778 work_flags = work->flags;
779 spin_lock_irqsave(&wqe->lock, flags);
780 wq_list_add_tail(&work->list, &wqe->work_list);
781 wqe->flags &= ~IO_WQE_FLAG_STALLED;
782 spin_unlock_irqrestore(&wqe->lock, flags);
784 if ((work_flags & IO_WQ_WORK_CONCURRENT) ||
785 !atomic_read(&acct->nr_running))
786 io_wqe_wake_worker(wqe, acct);
789 void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
791 struct io_wqe *wqe = wq->wqes[numa_node_id()];
793 io_wqe_enqueue(wqe, work);
797 * Enqueue work, hashed by some key. Work items that hash to the same value
798 * will not be done in parallel. Used to limit concurrent writes, generally
801 void io_wq_enqueue_hashed(struct io_wq *wq, struct io_wq_work *work, void *val)
803 struct io_wqe *wqe = wq->wqes[numa_node_id()];
807 bit = hash_ptr(val, IO_WQ_HASH_ORDER);
808 work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
809 io_wqe_enqueue(wqe, work);
812 static bool io_wqe_worker_send_sig(struct io_worker *worker, void *data)
814 send_sig(SIGINT, worker->task, 1);
819 * Iterate the passed in list and call the specific function for each
820 * worker that isn't exiting
822 static bool io_wq_for_each_worker(struct io_wqe *wqe,
823 bool (*func)(struct io_worker *, void *),
826 struct io_worker *worker;
829 list_for_each_entry_rcu(worker, &wqe->all_list, all_list) {
830 if (io_worker_get(worker)) {
831 /* no task if node is/was offline */
833 ret = func(worker, data);
834 io_worker_release(worker);
843 void io_wq_cancel_all(struct io_wq *wq)
847 set_bit(IO_WQ_BIT_CANCEL, &wq->state);
850 for_each_node(node) {
851 struct io_wqe *wqe = wq->wqes[node];
853 io_wq_for_each_worker(wqe, io_wqe_worker_send_sig, NULL);
858 struct io_cb_cancel_data {
860 work_cancel_fn *cancel;
864 static bool io_work_cancel(struct io_worker *worker, void *cancel_data)
866 struct io_cb_cancel_data *data = cancel_data;
871 * Hold the lock to avoid ->cur_work going out of scope, caller
872 * may dereference the passed in work.
874 spin_lock_irqsave(&worker->lock, flags);
875 if (worker->cur_work &&
876 !(worker->cur_work->flags & IO_WQ_WORK_NO_CANCEL) &&
877 data->cancel(worker->cur_work, data->caller_data)) {
878 send_sig(SIGINT, worker->task, 1);
881 spin_unlock_irqrestore(&worker->lock, flags);
886 static enum io_wq_cancel io_wqe_cancel_cb_work(struct io_wqe *wqe,
887 work_cancel_fn *cancel,
890 struct io_cb_cancel_data data = {
893 .caller_data = cancel_data,
895 struct io_wq_work_node *node, *prev;
896 struct io_wq_work *work;
900 spin_lock_irqsave(&wqe->lock, flags);
901 wq_list_for_each(node, prev, &wqe->work_list) {
902 work = container_of(node, struct io_wq_work, list);
904 if (cancel(work, cancel_data)) {
905 wq_node_del(&wqe->work_list, node, prev);
910 spin_unlock_irqrestore(&wqe->lock, flags);
914 return IO_WQ_CANCEL_OK;
918 found = io_wq_for_each_worker(wqe, io_work_cancel, &data);
920 return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND;
923 enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
926 enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
929 for_each_node(node) {
930 struct io_wqe *wqe = wq->wqes[node];
932 ret = io_wqe_cancel_cb_work(wqe, cancel, data);
933 if (ret != IO_WQ_CANCEL_NOTFOUND)
941 bool (*fn)(struct io_wq_work *, void *data);
945 static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
947 struct work_match *match = data;
951 spin_lock_irqsave(&worker->lock, flags);
952 if (match->fn(worker->cur_work, match->data) &&
953 !(worker->cur_work->flags & IO_WQ_WORK_NO_CANCEL)) {
954 send_sig(SIGINT, worker->task, 1);
957 spin_unlock_irqrestore(&worker->lock, flags);
962 static enum io_wq_cancel io_wqe_cancel_work(struct io_wqe *wqe,
963 struct work_match *match)
965 struct io_wq_work_node *node, *prev;
966 struct io_wq_work *work;
971 * First check pending list, if we're lucky we can just remove it
972 * from there. CANCEL_OK means that the work is returned as-new,
973 * no completion will be posted for it.
975 spin_lock_irqsave(&wqe->lock, flags);
976 wq_list_for_each(node, prev, &wqe->work_list) {
977 work = container_of(node, struct io_wq_work, list);
979 if (match->fn(work, match->data)) {
980 wq_node_del(&wqe->work_list, node, prev);
985 spin_unlock_irqrestore(&wqe->lock, flags);
989 return IO_WQ_CANCEL_OK;
993 * Now check if a free (going busy) or busy worker has the work
994 * currently running. If we find it there, we'll return CANCEL_RUNNING
995 * as an indication that we attempt to signal cancellation. The
996 * completion will run normally in this case.
999 found = io_wq_for_each_worker(wqe, io_wq_worker_cancel, match);
1001 return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND;
1004 static bool io_wq_work_match(struct io_wq_work *work, void *data)
1006 return work == data;
1009 enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork)
1011 struct work_match match = {
1012 .fn = io_wq_work_match,
1015 enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
1018 cwork->flags |= IO_WQ_WORK_CANCEL;
1020 for_each_node(node) {
1021 struct io_wqe *wqe = wq->wqes[node];
1023 ret = io_wqe_cancel_work(wqe, &match);
1024 if (ret != IO_WQ_CANCEL_NOTFOUND)
1031 static bool io_wq_pid_match(struct io_wq_work *work, void *data)
1033 pid_t pid = (pid_t) (unsigned long) data;
1036 return work->task_pid == pid;
1040 enum io_wq_cancel io_wq_cancel_pid(struct io_wq *wq, pid_t pid)
1042 struct work_match match = {
1043 .fn = io_wq_pid_match,
1044 .data = (void *) (unsigned long) pid
1046 enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
1049 for_each_node(node) {
1050 struct io_wqe *wqe = wq->wqes[node];
1052 ret = io_wqe_cancel_work(wqe, &match);
1053 if (ret != IO_WQ_CANCEL_NOTFOUND)
1060 struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
1062 int ret = -ENOMEM, node;
1065 wq = kzalloc(sizeof(*wq), GFP_KERNEL);
1067 return ERR_PTR(-ENOMEM);
1069 wq->wqes = kcalloc(nr_node_ids, sizeof(struct io_wqe *), GFP_KERNEL);
1072 return ERR_PTR(-ENOMEM);
1075 wq->get_work = data->get_work;
1076 wq->put_work = data->put_work;
1078 /* caller must already hold a reference to this */
1079 wq->user = data->user;
1081 for_each_node(node) {
1083 int alloc_node = node;
1085 if (!node_online(alloc_node))
1086 alloc_node = NUMA_NO_NODE;
1087 wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node);
1090 wq->wqes[node] = wqe;
1091 wqe->node = alloc_node;
1092 wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
1093 atomic_set(&wqe->acct[IO_WQ_ACCT_BOUND].nr_running, 0);
1095 wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
1096 task_rlimit(current, RLIMIT_NPROC);
1098 atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0);
1100 spin_lock_init(&wqe->lock);
1101 INIT_WQ_LIST(&wqe->work_list);
1102 INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0);
1103 INIT_LIST_HEAD(&wqe->all_list);
1106 init_completion(&wq->done);
1108 wq->manager = kthread_create(io_wq_manager, wq, "io_wq_manager");
1109 if (!IS_ERR(wq->manager)) {
1110 wake_up_process(wq->manager);
1111 wait_for_completion(&wq->done);
1112 if (test_bit(IO_WQ_BIT_ERROR, &wq->state)) {
1116 refcount_set(&wq->use_refs, 1);
1117 reinit_completion(&wq->done);
1121 ret = PTR_ERR(wq->manager);
1122 complete(&wq->done);
1125 kfree(wq->wqes[node]);
1128 return ERR_PTR(ret);
1131 bool io_wq_get(struct io_wq *wq, struct io_wq_data *data)
1133 if (data->get_work != wq->get_work || data->put_work != wq->put_work)
1136 return refcount_inc_not_zero(&wq->use_refs);
1139 static bool io_wq_worker_wake(struct io_worker *worker, void *data)
1141 wake_up_process(worker->task);
1145 static void __io_wq_destroy(struct io_wq *wq)
1149 set_bit(IO_WQ_BIT_EXIT, &wq->state);
1151 kthread_stop(wq->manager);
1155 io_wq_for_each_worker(wq->wqes[node], io_wq_worker_wake, NULL);
1158 wait_for_completion(&wq->done);
1161 kfree(wq->wqes[node]);
1166 void io_wq_destroy(struct io_wq *wq)
1168 if (refcount_dec_and_test(&wq->use_refs))
1169 __io_wq_destroy(wq);