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/sched/mm.h>
14 #include <linux/percpu.h>
15 #include <linux/slab.h>
16 #include <linux/kthread.h>
17 #include <linux/rculist_nulls.h>
18 #include <linux/fs_struct.h>
19 #include <linux/task_work.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
72 #define IO_WQ_NR_HASH_BUCKETS (1u << IO_WQ_HASH_ORDER)
86 * Per-node worker thread pool
91 struct io_wq_work_list work_list;
92 unsigned long hash_map;
94 } ____cacheline_aligned_in_smp;
97 struct io_wqe_acct acct[2];
99 struct hlist_nulls_head free_list;
100 struct list_head all_list;
103 struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS];
110 struct io_wqe **wqes;
113 free_work_fn *free_work;
114 io_wq_work_fn *do_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);
173 kthread_unuse_mm(worker->mm);
181 static inline struct io_wqe_acct *io_work_get_acct(struct io_wqe *wqe,
182 struct io_wq_work *work)
184 if (work->flags & IO_WQ_WORK_UNBOUND)
185 return &wqe->acct[IO_WQ_ACCT_UNBOUND];
187 return &wqe->acct[IO_WQ_ACCT_BOUND];
190 static inline struct io_wqe_acct *io_wqe_get_acct(struct io_wqe *wqe,
191 struct io_worker *worker)
193 if (worker->flags & IO_WORKER_F_BOUND)
194 return &wqe->acct[IO_WQ_ACCT_BOUND];
196 return &wqe->acct[IO_WQ_ACCT_UNBOUND];
199 static void io_worker_exit(struct io_worker *worker)
201 struct io_wqe *wqe = worker->wqe;
202 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
206 * If we're not at zero, someone else is holding a brief reference
207 * to the worker. Wait for that to go away.
209 set_current_state(TASK_INTERRUPTIBLE);
210 if (!refcount_dec_and_test(&worker->ref))
212 __set_current_state(TASK_RUNNING);
215 current->flags &= ~PF_IO_WORKER;
216 if (worker->flags & IO_WORKER_F_RUNNING)
217 atomic_dec(&acct->nr_running);
218 if (!(worker->flags & IO_WORKER_F_BOUND))
219 atomic_dec(&wqe->wq->user->processes);
223 spin_lock_irq(&wqe->lock);
224 hlist_nulls_del_rcu(&worker->nulls_node);
225 list_del_rcu(&worker->all_list);
226 if (__io_worker_unuse(wqe, worker)) {
227 __release(&wqe->lock);
228 spin_lock_irq(&wqe->lock);
231 nr_workers = wqe->acct[IO_WQ_ACCT_BOUND].nr_workers +
232 wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers;
233 spin_unlock_irq(&wqe->lock);
235 /* all workers gone, wq exit can proceed */
236 if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs))
237 complete(&wqe->wq->done);
239 kfree_rcu(worker, rcu);
242 static inline bool io_wqe_run_queue(struct io_wqe *wqe)
243 __must_hold(wqe->lock)
245 if (!wq_list_empty(&wqe->work_list) &&
246 !(wqe->flags & IO_WQE_FLAG_STALLED))
252 * Check head of free list for an available worker. If one isn't available,
253 * caller must wake up the wq manager to create one.
255 static bool io_wqe_activate_free_worker(struct io_wqe *wqe)
258 struct hlist_nulls_node *n;
259 struct io_worker *worker;
261 n = rcu_dereference(hlist_nulls_first_rcu(&wqe->free_list));
265 worker = hlist_nulls_entry(n, struct io_worker, nulls_node);
266 if (io_worker_get(worker)) {
267 wake_up_process(worker->task);
268 io_worker_release(worker);
276 * We need a worker. If we find a free one, we're good. If not, and we're
277 * below the max number of workers, wake up the manager to create one.
279 static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
284 * Most likely an attempt to queue unbounded work on an io_wq that
285 * wasn't setup with any unbounded workers.
287 WARN_ON_ONCE(!acct->max_workers);
290 ret = io_wqe_activate_free_worker(wqe);
293 if (!ret && acct->nr_workers < acct->max_workers)
294 wake_up_process(wqe->wq->manager);
297 static void io_wqe_inc_running(struct io_wqe *wqe, struct io_worker *worker)
299 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
301 atomic_inc(&acct->nr_running);
304 static void io_wqe_dec_running(struct io_wqe *wqe, struct io_worker *worker)
305 __must_hold(wqe->lock)
307 struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
309 if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe))
310 io_wqe_wake_worker(wqe, acct);
313 static void io_worker_start(struct io_wqe *wqe, struct io_worker *worker)
315 allow_kernel_signal(SIGINT);
317 current->flags |= PF_IO_WORKER;
319 worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
320 worker->restore_files = current->files;
321 worker->restore_fs = current->fs;
322 io_wqe_inc_running(wqe, worker);
326 * Worker will start processing some work. Move it to the busy list, if
327 * it's currently on the freelist
329 static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
330 struct io_wq_work *work)
331 __must_hold(wqe->lock)
333 bool worker_bound, work_bound;
335 if (worker->flags & IO_WORKER_F_FREE) {
336 worker->flags &= ~IO_WORKER_F_FREE;
337 hlist_nulls_del_init_rcu(&worker->nulls_node);
341 * If worker is moving from bound to unbound (or vice versa), then
342 * ensure we update the running accounting.
344 worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
345 work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
346 if (worker_bound != work_bound) {
347 io_wqe_dec_running(wqe, worker);
349 worker->flags |= IO_WORKER_F_BOUND;
350 wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
351 wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
352 atomic_dec(&wqe->wq->user->processes);
354 worker->flags &= ~IO_WORKER_F_BOUND;
355 wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
356 wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
357 atomic_inc(&wqe->wq->user->processes);
359 io_wqe_inc_running(wqe, worker);
364 * No work, worker going to sleep. Move to freelist, and unuse mm if we
365 * have one attached. Dropping the mm may potentially sleep, so we drop
366 * the lock in that case and return success. Since the caller has to
367 * retry the loop in that case (we changed task state), we don't regrab
368 * the lock if we return success.
370 static bool __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker)
371 __must_hold(wqe->lock)
373 if (!(worker->flags & IO_WORKER_F_FREE)) {
374 worker->flags |= IO_WORKER_F_FREE;
375 hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
378 return __io_worker_unuse(wqe, worker);
381 static inline unsigned int io_get_work_hash(struct io_wq_work *work)
383 return work->flags >> IO_WQ_HASH_SHIFT;
386 static struct io_wq_work *io_get_next_work(struct io_wqe *wqe)
387 __must_hold(wqe->lock)
389 struct io_wq_work_node *node, *prev;
390 struct io_wq_work *work, *tail;
393 wq_list_for_each(node, prev, &wqe->work_list) {
394 work = container_of(node, struct io_wq_work, list);
396 /* not hashed, can run anytime */
397 if (!io_wq_is_hashed(work)) {
398 wq_list_del(&wqe->work_list, node, prev);
402 /* hashed, can run if not already running */
403 hash = io_get_work_hash(work);
404 if (!(wqe->hash_map & BIT(hash))) {
405 wqe->hash_map |= BIT(hash);
406 /* all items with this hash lie in [work, tail] */
407 tail = wqe->hash_tail[hash];
408 wqe->hash_tail[hash] = NULL;
409 wq_list_cut(&wqe->work_list, &tail->list, prev);
417 static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work)
420 kthread_unuse_mm(worker->mm);
427 if (mmget_not_zero(work->mm)) {
428 kthread_use_mm(work->mm);
429 worker->mm = work->mm;
430 /* hang on to this mm */
435 /* failed grabbing mm, ensure work gets cancelled */
436 work->flags |= IO_WQ_WORK_CANCEL;
439 static void io_wq_switch_creds(struct io_worker *worker,
440 struct io_wq_work *work)
442 const struct cred *old_creds = override_creds(work->creds);
444 worker->cur_creds = work->creds;
445 if (worker->saved_creds)
446 put_cred(old_creds); /* creds set by previous switch */
448 worker->saved_creds = old_creds;
451 static void io_impersonate_work(struct io_worker *worker,
452 struct io_wq_work *work)
454 if (work->files && current->files != work->files) {
456 current->files = work->files;
457 task_unlock(current);
459 if (work->fs && current->fs != work->fs)
460 current->fs = work->fs;
461 if (work->mm != worker->mm)
462 io_wq_switch_mm(worker, work);
463 if (worker->cur_creds != work->creds)
464 io_wq_switch_creds(worker, work);
465 current->signal->rlim[RLIMIT_FSIZE].rlim_cur = work->fsize;
468 static void io_assign_current_work(struct io_worker *worker,
469 struct io_wq_work *work)
472 /* flush 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);
483 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work);
485 static void io_worker_handle_work(struct io_worker *worker)
486 __releases(wqe->lock)
488 struct io_wqe *wqe = worker->wqe;
489 struct io_wq *wq = wqe->wq;
492 struct io_wq_work *work;
495 * If we got some work, mark us as busy. If we didn't, but
496 * the list isn't empty, it means we stalled on hashed work.
497 * Mark us stalled so we don't keep looking for work when we
498 * can't make progress, any work completion or insertion will
499 * clear the stalled flag.
501 work = io_get_next_work(wqe);
503 __io_worker_busy(wqe, worker, work);
504 else if (!wq_list_empty(&wqe->work_list))
505 wqe->flags |= IO_WQE_FLAG_STALLED;
507 spin_unlock_irq(&wqe->lock);
510 io_assign_current_work(worker, work);
512 /* handle a whole dependent link */
514 struct io_wq_work *old_work, *next_hashed, *linked;
515 unsigned int hash = io_get_work_hash(work);
517 next_hashed = wq_next_work(work);
518 io_impersonate_work(worker, work);
520 * OK to set IO_WQ_WORK_CANCEL even for uncancellable
521 * work, the worker function will do the right thing.
523 if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
524 work->flags |= IO_WQ_WORK_CANCEL;
527 linked = wq->do_work(work);
530 if (!work && linked && !io_wq_is_hashed(linked)) {
534 io_assign_current_work(worker, work);
535 wq->free_work(old_work);
538 io_wqe_enqueue(wqe, linked);
540 if (hash != -1U && !next_hashed) {
541 spin_lock_irq(&wqe->lock);
542 wqe->hash_map &= ~BIT_ULL(hash);
543 wqe->flags &= ~IO_WQE_FLAG_STALLED;
544 /* skip unnecessary unlock-lock wqe->lock */
547 spin_unlock_irq(&wqe->lock);
551 spin_lock_irq(&wqe->lock);
555 static int io_wqe_worker(void *data)
557 struct io_worker *worker = data;
558 struct io_wqe *wqe = worker->wqe;
559 struct io_wq *wq = wqe->wq;
561 io_worker_start(wqe, worker);
563 while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
564 set_current_state(TASK_INTERRUPTIBLE);
566 spin_lock_irq(&wqe->lock);
567 if (io_wqe_run_queue(wqe)) {
568 __set_current_state(TASK_RUNNING);
569 io_worker_handle_work(worker);
572 /* drops the lock on success, retry */
573 if (__io_worker_idle(wqe, worker)) {
574 __release(&wqe->lock);
577 spin_unlock_irq(&wqe->lock);
578 if (signal_pending(current))
579 flush_signals(current);
580 if (schedule_timeout(WORKER_IDLE_TIMEOUT))
582 /* timed out, exit unless we're the fixed worker */
583 if (test_bit(IO_WQ_BIT_EXIT, &wq->state) ||
584 !(worker->flags & IO_WORKER_F_FIXED))
588 if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
589 spin_lock_irq(&wqe->lock);
590 if (!wq_list_empty(&wqe->work_list))
591 io_worker_handle_work(worker);
593 spin_unlock_irq(&wqe->lock);
596 io_worker_exit(worker);
601 * Called when a worker is scheduled in. Mark us as currently running.
603 void io_wq_worker_running(struct task_struct *tsk)
605 struct io_worker *worker = kthread_data(tsk);
606 struct io_wqe *wqe = worker->wqe;
608 if (!(worker->flags & IO_WORKER_F_UP))
610 if (worker->flags & IO_WORKER_F_RUNNING)
612 worker->flags |= IO_WORKER_F_RUNNING;
613 io_wqe_inc_running(wqe, worker);
617 * Called when worker is going to sleep. If there are no workers currently
618 * running and we have work pending, wake up a free one or have the manager
621 void io_wq_worker_sleeping(struct task_struct *tsk)
623 struct io_worker *worker = kthread_data(tsk);
624 struct io_wqe *wqe = worker->wqe;
626 if (!(worker->flags & IO_WORKER_F_UP))
628 if (!(worker->flags & IO_WORKER_F_RUNNING))
631 worker->flags &= ~IO_WORKER_F_RUNNING;
633 spin_lock_irq(&wqe->lock);
634 io_wqe_dec_running(wqe, worker);
635 spin_unlock_irq(&wqe->lock);
638 static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
640 struct io_wqe_acct *acct =&wqe->acct[index];
641 struct io_worker *worker;
643 worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, wqe->node);
647 refcount_set(&worker->ref, 1);
648 worker->nulls_node.pprev = NULL;
650 spin_lock_init(&worker->lock);
652 worker->task = kthread_create_on_node(io_wqe_worker, worker, wqe->node,
653 "io_wqe_worker-%d/%d", index, wqe->node);
654 if (IS_ERR(worker->task)) {
659 spin_lock_irq(&wqe->lock);
660 hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
661 list_add_tail_rcu(&worker->all_list, &wqe->all_list);
662 worker->flags |= IO_WORKER_F_FREE;
663 if (index == IO_WQ_ACCT_BOUND)
664 worker->flags |= IO_WORKER_F_BOUND;
665 if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND))
666 worker->flags |= IO_WORKER_F_FIXED;
668 spin_unlock_irq(&wqe->lock);
670 if (index == IO_WQ_ACCT_UNBOUND)
671 atomic_inc(&wq->user->processes);
673 wake_up_process(worker->task);
677 static inline bool io_wqe_need_worker(struct io_wqe *wqe, int index)
678 __must_hold(wqe->lock)
680 struct io_wqe_acct *acct = &wqe->acct[index];
682 /* if we have available workers or no work, no need */
683 if (!hlist_nulls_empty(&wqe->free_list) || !io_wqe_run_queue(wqe))
685 return acct->nr_workers < acct->max_workers;
689 * Manager thread. Tasked with creating new workers, if we need them.
691 static int io_wq_manager(void *data)
693 struct io_wq *wq = data;
694 int workers_to_create = num_possible_nodes();
697 /* create fixed workers */
698 refcount_set(&wq->refs, workers_to_create);
699 for_each_node(node) {
700 if (!node_online(node))
702 if (!create_io_worker(wq, wq->wqes[node], IO_WQ_ACCT_BOUND))
707 while (workers_to_create--)
708 refcount_dec(&wq->refs);
712 while (!kthread_should_stop()) {
713 if (current->task_works)
716 for_each_node(node) {
717 struct io_wqe *wqe = wq->wqes[node];
718 bool fork_worker[2] = { false, false };
720 if (!node_online(node))
723 spin_lock_irq(&wqe->lock);
724 if (io_wqe_need_worker(wqe, IO_WQ_ACCT_BOUND))
725 fork_worker[IO_WQ_ACCT_BOUND] = true;
726 if (io_wqe_need_worker(wqe, IO_WQ_ACCT_UNBOUND))
727 fork_worker[IO_WQ_ACCT_UNBOUND] = true;
728 spin_unlock_irq(&wqe->lock);
729 if (fork_worker[IO_WQ_ACCT_BOUND])
730 create_io_worker(wq, wqe, IO_WQ_ACCT_BOUND);
731 if (fork_worker[IO_WQ_ACCT_UNBOUND])
732 create_io_worker(wq, wqe, IO_WQ_ACCT_UNBOUND);
734 set_current_state(TASK_INTERRUPTIBLE);
735 schedule_timeout(HZ);
738 if (current->task_works)
743 set_bit(IO_WQ_BIT_ERROR, &wq->state);
744 set_bit(IO_WQ_BIT_EXIT, &wq->state);
745 if (refcount_sub_and_test(workers_to_create, &wq->refs))
750 static bool io_wq_can_queue(struct io_wqe *wqe, struct io_wqe_acct *acct,
751 struct io_wq_work *work)
755 if (!(work->flags & IO_WQ_WORK_UNBOUND))
757 if (atomic_read(&acct->nr_running))
761 free_worker = !hlist_nulls_empty(&wqe->free_list);
766 if (atomic_read(&wqe->wq->user->processes) >= acct->max_workers &&
767 !(capable(CAP_SYS_RESOURCE) || capable(CAP_SYS_ADMIN)))
773 static void io_run_cancel(struct io_wq_work *work, struct io_wqe *wqe)
775 struct io_wq *wq = wqe->wq;
778 struct io_wq_work *old_work = work;
780 work->flags |= IO_WQ_WORK_CANCEL;
781 work = wq->do_work(work);
782 wq->free_work(old_work);
786 static void io_wqe_insert_work(struct io_wqe *wqe, struct io_wq_work *work)
789 struct io_wq_work *tail;
791 if (!io_wq_is_hashed(work)) {
793 wq_list_add_tail(&work->list, &wqe->work_list);
797 hash = io_get_work_hash(work);
798 tail = wqe->hash_tail[hash];
799 wqe->hash_tail[hash] = work;
803 wq_list_add_after(&work->list, &tail->list, &wqe->work_list);
806 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
808 struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
813 * Do early check to see if we need a new unbound worker, and if we do,
814 * if we're allowed to do so. This isn't 100% accurate as there's a
815 * gap between this check and incrementing the value, but that's OK.
816 * It's close enough to not be an issue, fork() has the same delay.
818 if (unlikely(!io_wq_can_queue(wqe, acct, work))) {
819 io_run_cancel(work, wqe);
823 work_flags = work->flags;
824 spin_lock_irqsave(&wqe->lock, flags);
825 io_wqe_insert_work(wqe, work);
826 wqe->flags &= ~IO_WQE_FLAG_STALLED;
827 spin_unlock_irqrestore(&wqe->lock, flags);
829 if ((work_flags & IO_WQ_WORK_CONCURRENT) ||
830 !atomic_read(&acct->nr_running))
831 io_wqe_wake_worker(wqe, acct);
834 void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
836 struct io_wqe *wqe = wq->wqes[numa_node_id()];
838 io_wqe_enqueue(wqe, work);
842 * Work items that hash to the same value will not be done in parallel.
843 * Used to limit concurrent writes, generally hashed by inode.
845 void io_wq_hash_work(struct io_wq_work *work, void *val)
849 bit = hash_ptr(val, IO_WQ_HASH_ORDER);
850 work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
853 static bool io_wqe_worker_send_sig(struct io_worker *worker, void *data)
855 send_sig(SIGINT, worker->task, 1);
860 * Iterate the passed in list and call the specific function for each
861 * worker that isn't exiting
863 static bool io_wq_for_each_worker(struct io_wqe *wqe,
864 bool (*func)(struct io_worker *, void *),
867 struct io_worker *worker;
870 list_for_each_entry_rcu(worker, &wqe->all_list, all_list) {
871 if (io_worker_get(worker)) {
872 /* no task if node is/was offline */
874 ret = func(worker, data);
875 io_worker_release(worker);
884 void io_wq_cancel_all(struct io_wq *wq)
888 set_bit(IO_WQ_BIT_CANCEL, &wq->state);
891 for_each_node(node) {
892 struct io_wqe *wqe = wq->wqes[node];
894 io_wq_for_each_worker(wqe, io_wqe_worker_send_sig, NULL);
899 struct io_cb_cancel_data {
907 static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
909 struct io_cb_cancel_data *match = data;
913 * Hold the lock to avoid ->cur_work going out of scope, caller
914 * may dereference the passed in work.
916 spin_lock_irqsave(&worker->lock, flags);
917 if (worker->cur_work &&
918 !(worker->cur_work->flags & IO_WQ_WORK_NO_CANCEL) &&
919 match->fn(worker->cur_work, match->data)) {
920 send_sig(SIGINT, worker->task, 1);
923 spin_unlock_irqrestore(&worker->lock, flags);
925 return match->nr_running && !match->cancel_all;
928 static void io_wqe_cancel_pending_work(struct io_wqe *wqe,
929 struct io_cb_cancel_data *match)
931 struct io_wq_work_node *node, *prev;
932 struct io_wq_work *work;
936 spin_lock_irqsave(&wqe->lock, flags);
937 wq_list_for_each(node, prev, &wqe->work_list) {
938 work = container_of(node, struct io_wq_work, list);
939 if (!match->fn(work, match->data))
942 wq_list_del(&wqe->work_list, node, prev);
943 spin_unlock_irqrestore(&wqe->lock, flags);
944 io_run_cancel(work, wqe);
946 if (!match->cancel_all)
949 /* not safe to continue after unlock */
952 spin_unlock_irqrestore(&wqe->lock, flags);
955 static void io_wqe_cancel_running_work(struct io_wqe *wqe,
956 struct io_cb_cancel_data *match)
959 io_wq_for_each_worker(wqe, io_wq_worker_cancel, match);
963 enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
964 void *data, bool cancel_all)
966 struct io_cb_cancel_data match = {
969 .cancel_all = cancel_all,
974 * First check pending list, if we're lucky we can just remove it
975 * from there. CANCEL_OK means that the work is returned as-new,
976 * no completion will be posted for it.
978 for_each_node(node) {
979 struct io_wqe *wqe = wq->wqes[node];
981 io_wqe_cancel_pending_work(wqe, &match);
982 if (match.nr_pending && !match.cancel_all)
983 return IO_WQ_CANCEL_OK;
987 * Now check if a free (going busy) or busy worker has the work
988 * currently running. If we find it there, we'll return CANCEL_RUNNING
989 * as an indication that we attempt to signal cancellation. The
990 * completion will run normally in this case.
992 for_each_node(node) {
993 struct io_wqe *wqe = wq->wqes[node];
995 io_wqe_cancel_running_work(wqe, &match);
996 if (match.nr_running && !match.cancel_all)
997 return IO_WQ_CANCEL_RUNNING;
1000 if (match.nr_running)
1001 return IO_WQ_CANCEL_RUNNING;
1002 if (match.nr_pending)
1003 return IO_WQ_CANCEL_OK;
1004 return IO_WQ_CANCEL_NOTFOUND;
1007 static bool io_wq_io_cb_cancel_data(struct io_wq_work *work, void *data)
1009 return work == data;
1012 enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork)
1014 return io_wq_cancel_cb(wq, io_wq_io_cb_cancel_data, (void *)cwork, false);
1017 struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
1019 int ret = -ENOMEM, node;
1022 if (WARN_ON_ONCE(!data->free_work || !data->do_work))
1023 return ERR_PTR(-EINVAL);
1025 wq = kzalloc(sizeof(*wq), GFP_KERNEL);
1027 return ERR_PTR(-ENOMEM);
1029 wq->wqes = kcalloc(nr_node_ids, sizeof(struct io_wqe *), GFP_KERNEL);
1032 return ERR_PTR(-ENOMEM);
1035 wq->free_work = data->free_work;
1036 wq->do_work = data->do_work;
1038 /* caller must already hold a reference to this */
1039 wq->user = data->user;
1041 for_each_node(node) {
1043 int alloc_node = node;
1045 if (!node_online(alloc_node))
1046 alloc_node = NUMA_NO_NODE;
1047 wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node);
1050 wq->wqes[node] = wqe;
1051 wqe->node = alloc_node;
1052 wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
1053 atomic_set(&wqe->acct[IO_WQ_ACCT_BOUND].nr_running, 0);
1055 wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
1056 task_rlimit(current, RLIMIT_NPROC);
1058 atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0);
1060 spin_lock_init(&wqe->lock);
1061 INIT_WQ_LIST(&wqe->work_list);
1062 INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0);
1063 INIT_LIST_HEAD(&wqe->all_list);
1066 init_completion(&wq->done);
1068 wq->manager = kthread_create(io_wq_manager, wq, "io_wq_manager");
1069 if (!IS_ERR(wq->manager)) {
1070 wake_up_process(wq->manager);
1071 wait_for_completion(&wq->done);
1072 if (test_bit(IO_WQ_BIT_ERROR, &wq->state)) {
1076 refcount_set(&wq->use_refs, 1);
1077 reinit_completion(&wq->done);
1081 ret = PTR_ERR(wq->manager);
1082 complete(&wq->done);
1085 kfree(wq->wqes[node]);
1088 return ERR_PTR(ret);
1091 bool io_wq_get(struct io_wq *wq, struct io_wq_data *data)
1093 if (data->free_work != wq->free_work || data->do_work != wq->do_work)
1096 return refcount_inc_not_zero(&wq->use_refs);
1099 static bool io_wq_worker_wake(struct io_worker *worker, void *data)
1101 wake_up_process(worker->task);
1105 static void __io_wq_destroy(struct io_wq *wq)
1109 set_bit(IO_WQ_BIT_EXIT, &wq->state);
1111 kthread_stop(wq->manager);
1115 io_wq_for_each_worker(wq->wqes[node], io_wq_worker_wake, NULL);
1118 wait_for_completion(&wq->done);
1121 kfree(wq->wqes[node]);
1126 void io_wq_destroy(struct io_wq *wq)
1128 if (refcount_dec_and_test(&wq->use_refs))
1129 __io_wq_destroy(wq);
1132 struct task_struct *io_wq_get_task(struct io_wq *wq)