1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/net/sunrpc/sched.c
5 * Scheduling for synchronous and asynchronous RPC requests.
7 * Copyright (C) 1996 Olaf Kirch, <okir@monad.swb.de>
9 * TCP NFS related read + write fixes
10 * (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
13 #include <linux/module.h>
15 #include <linux/sched.h>
16 #include <linux/interrupt.h>
17 #include <linux/slab.h>
18 #include <linux/mempool.h>
19 #include <linux/smp.h>
20 #include <linux/spinlock.h>
21 #include <linux/mutex.h>
22 #include <linux/freezer.h>
23 #include <linux/sched/mm.h>
25 #include <linux/sunrpc/clnt.h>
26 #include <linux/sunrpc/metrics.h>
30 #define CREATE_TRACE_POINTS
31 #include <trace/events/sunrpc.h>
34 * RPC slabs and memory pools
36 #define RPC_BUFFER_MAXSIZE (2048)
37 #define RPC_BUFFER_POOLSIZE (8)
38 #define RPC_TASK_POOLSIZE (8)
39 static struct kmem_cache *rpc_task_slabp __read_mostly;
40 static struct kmem_cache *rpc_buffer_slabp __read_mostly;
41 static mempool_t *rpc_task_mempool __read_mostly;
42 static mempool_t *rpc_buffer_mempool __read_mostly;
44 static void rpc_async_schedule(struct work_struct *);
45 static void rpc_release_task(struct rpc_task *task);
46 static void __rpc_queue_timer_fn(struct work_struct *);
49 * RPC tasks sit here while waiting for conditions to improve.
51 static struct rpc_wait_queue delay_queue;
54 * rpciod-related stuff
56 struct workqueue_struct *rpciod_workqueue __read_mostly;
57 struct workqueue_struct *xprtiod_workqueue __read_mostly;
58 EXPORT_SYMBOL_GPL(xprtiod_workqueue);
61 rpc_task_timeout(const struct rpc_task *task)
63 unsigned long timeout = READ_ONCE(task->tk_timeout);
66 unsigned long now = jiffies;
67 if (time_before(now, timeout))
72 EXPORT_SYMBOL_GPL(rpc_task_timeout);
75 * Disable the timer for a given RPC task. Should be called with
76 * queue->lock and bh_disabled in order to avoid races within
80 __rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
82 if (list_empty(&task->u.tk_wait.timer_list))
85 list_del(&task->u.tk_wait.timer_list);
86 if (list_empty(&queue->timer_list.list))
87 cancel_delayed_work(&queue->timer_list.dwork);
91 rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)
93 unsigned long now = jiffies;
94 queue->timer_list.expires = expires;
95 if (time_before_eq(expires, now))
99 mod_delayed_work(rpciod_workqueue, &queue->timer_list.dwork, expires);
103 * Set up a timer for the current task.
106 __rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task,
107 unsigned long timeout)
109 task->tk_timeout = timeout;
110 if (list_empty(&queue->timer_list.list) || time_before(timeout, queue->timer_list.expires))
111 rpc_set_queue_timer(queue, timeout);
112 list_add(&task->u.tk_wait.timer_list, &queue->timer_list.list);
115 static void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
117 if (queue->priority != priority) {
118 queue->priority = priority;
119 queue->nr = 1U << priority;
123 static void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
125 rpc_set_waitqueue_priority(queue, queue->maxpriority);
129 * Add a request to a queue list
132 __rpc_list_enqueue_task(struct list_head *q, struct rpc_task *task)
136 list_for_each_entry(t, q, u.tk_wait.list) {
137 if (t->tk_owner == task->tk_owner) {
138 list_add_tail(&task->u.tk_wait.links,
139 &t->u.tk_wait.links);
140 /* Cache the queue head in task->u.tk_wait.list */
141 task->u.tk_wait.list.next = q;
142 task->u.tk_wait.list.prev = NULL;
146 INIT_LIST_HEAD(&task->u.tk_wait.links);
147 list_add_tail(&task->u.tk_wait.list, q);
151 * Remove request from a queue list
154 __rpc_list_dequeue_task(struct rpc_task *task)
159 if (task->u.tk_wait.list.prev == NULL) {
160 list_del(&task->u.tk_wait.links);
163 if (!list_empty(&task->u.tk_wait.links)) {
164 t = list_first_entry(&task->u.tk_wait.links,
167 /* Assume __rpc_list_enqueue_task() cached the queue head */
168 q = t->u.tk_wait.list.next;
169 list_add_tail(&t->u.tk_wait.list, q);
170 list_del(&task->u.tk_wait.links);
172 list_del(&task->u.tk_wait.list);
176 * Add new request to a priority queue.
178 static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue,
179 struct rpc_task *task,
180 unsigned char queue_priority)
182 if (unlikely(queue_priority > queue->maxpriority))
183 queue_priority = queue->maxpriority;
184 __rpc_list_enqueue_task(&queue->tasks[queue_priority], task);
188 * Add new request to wait queue.
190 * Swapper tasks always get inserted at the head of the queue.
191 * This should avoid many nasty memory deadlocks and hopefully
192 * improve overall performance.
193 * Everyone else gets appended to the queue to ensure proper FIFO behavior.
195 static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
196 struct rpc_task *task,
197 unsigned char queue_priority)
199 INIT_LIST_HEAD(&task->u.tk_wait.timer_list);
200 if (RPC_IS_PRIORITY(queue))
201 __rpc_add_wait_queue_priority(queue, task, queue_priority);
202 else if (RPC_IS_SWAPPER(task))
203 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
205 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
206 task->tk_waitqueue = queue;
208 /* barrier matches the read in rpc_wake_up_task_queue_locked() */
210 rpc_set_queued(task);
214 * Remove request from a priority queue.
216 static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
218 __rpc_list_dequeue_task(task);
222 * Remove request from queue.
223 * Note: must be called with spin lock held.
225 static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
227 __rpc_disable_timer(queue, task);
228 if (RPC_IS_PRIORITY(queue))
229 __rpc_remove_wait_queue_priority(task);
231 list_del(&task->u.tk_wait.list);
235 static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
239 spin_lock_init(&queue->lock);
240 for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
241 INIT_LIST_HEAD(&queue->tasks[i]);
242 queue->maxpriority = nr_queues - 1;
243 rpc_reset_waitqueue_priority(queue);
245 queue->timer_list.expires = 0;
246 INIT_DELAYED_WORK(&queue->timer_list.dwork, __rpc_queue_timer_fn);
247 INIT_LIST_HEAD(&queue->timer_list.list);
248 rpc_assign_waitqueue_name(queue, qname);
251 void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
253 __rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY);
255 EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue);
257 void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
259 __rpc_init_priority_wait_queue(queue, qname, 1);
261 EXPORT_SYMBOL_GPL(rpc_init_wait_queue);
263 void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)
265 cancel_delayed_work_sync(&queue->timer_list.dwork);
267 EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
269 static int rpc_wait_bit_killable(struct wait_bit_key *key, int mode)
271 freezable_schedule_unsafe();
272 if (signal_pending_state(mode, current))
277 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS)
278 static void rpc_task_set_debuginfo(struct rpc_task *task)
280 struct rpc_clnt *clnt = task->tk_client;
282 /* Might be a task carrying a reverse-direction operation */
284 static atomic_t rpc_pid;
286 task->tk_pid = atomic_inc_return(&rpc_pid);
290 task->tk_pid = atomic_inc_return(&clnt->cl_pid);
293 static inline void rpc_task_set_debuginfo(struct rpc_task *task)
298 static void rpc_set_active(struct rpc_task *task)
300 rpc_task_set_debuginfo(task);
301 set_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
302 trace_rpc_task_begin(task, NULL);
306 * Mark an RPC call as having completed by clearing the 'active' bit
307 * and then waking up all tasks that were sleeping.
309 static int rpc_complete_task(struct rpc_task *task)
311 void *m = &task->tk_runstate;
312 wait_queue_head_t *wq = bit_waitqueue(m, RPC_TASK_ACTIVE);
313 struct wait_bit_key k = __WAIT_BIT_KEY_INITIALIZER(m, RPC_TASK_ACTIVE);
317 trace_rpc_task_complete(task, NULL);
319 spin_lock_irqsave(&wq->lock, flags);
320 clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
321 ret = atomic_dec_and_test(&task->tk_count);
322 if (waitqueue_active(wq))
323 __wake_up_locked_key(wq, TASK_NORMAL, &k);
324 spin_unlock_irqrestore(&wq->lock, flags);
329 * Allow callers to wait for completion of an RPC call
331 * Note the use of out_of_line_wait_on_bit() rather than wait_on_bit()
332 * to enforce taking of the wq->lock and hence avoid races with
333 * rpc_complete_task().
335 int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *action)
338 action = rpc_wait_bit_killable;
339 return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
340 action, TASK_KILLABLE);
342 EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
345 * Make an RPC task runnable.
347 * Note: If the task is ASYNC, and is being made runnable after sitting on an
348 * rpc_wait_queue, this must be called with the queue spinlock held to protect
349 * the wait queue operation.
350 * Note the ordering of rpc_test_and_set_running() and rpc_clear_queued(),
351 * which is needed to ensure that __rpc_execute() doesn't loop (due to the
352 * lockless RPC_IS_QUEUED() test) before we've had a chance to test
353 * the RPC_TASK_RUNNING flag.
355 static void rpc_make_runnable(struct workqueue_struct *wq,
356 struct rpc_task *task)
358 bool need_wakeup = !rpc_test_and_set_running(task);
360 rpc_clear_queued(task);
363 if (RPC_IS_ASYNC(task)) {
364 INIT_WORK(&task->u.tk_work, rpc_async_schedule);
365 queue_work(wq, &task->u.tk_work);
367 wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
371 * Prepare for sleeping on a wait queue.
372 * By always appending tasks to the list we ensure FIFO behavior.
373 * NB: An RPC task will only receive interrupt-driven events as long
374 * as it's on a wait queue.
376 static void __rpc_do_sleep_on_priority(struct rpc_wait_queue *q,
377 struct rpc_task *task,
378 unsigned char queue_priority)
380 trace_rpc_task_sleep(task, q);
382 __rpc_add_wait_queue(q, task, queue_priority);
385 static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
386 struct rpc_task *task,
387 unsigned char queue_priority)
389 if (WARN_ON_ONCE(RPC_IS_QUEUED(task)))
391 __rpc_do_sleep_on_priority(q, task, queue_priority);
394 static void __rpc_sleep_on_priority_timeout(struct rpc_wait_queue *q,
395 struct rpc_task *task, unsigned long timeout,
396 unsigned char queue_priority)
398 if (WARN_ON_ONCE(RPC_IS_QUEUED(task)))
400 if (time_is_after_jiffies(timeout)) {
401 __rpc_do_sleep_on_priority(q, task, queue_priority);
402 __rpc_add_timer(q, task, timeout);
404 task->tk_status = -ETIMEDOUT;
407 static void rpc_set_tk_callback(struct rpc_task *task, rpc_action action)
409 if (action && !WARN_ON_ONCE(task->tk_callback != NULL))
410 task->tk_callback = action;
413 static bool rpc_sleep_check_activated(struct rpc_task *task)
415 /* We shouldn't ever put an inactive task to sleep */
416 if (WARN_ON_ONCE(!RPC_IS_ACTIVATED(task))) {
417 task->tk_status = -EIO;
418 rpc_put_task_async(task);
424 void rpc_sleep_on_timeout(struct rpc_wait_queue *q, struct rpc_task *task,
425 rpc_action action, unsigned long timeout)
427 if (!rpc_sleep_check_activated(task))
430 rpc_set_tk_callback(task, action);
433 * Protect the queue operations.
436 __rpc_sleep_on_priority_timeout(q, task, timeout, task->tk_priority);
437 spin_unlock(&q->lock);
439 EXPORT_SYMBOL_GPL(rpc_sleep_on_timeout);
441 void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
444 if (!rpc_sleep_check_activated(task))
447 rpc_set_tk_callback(task, action);
449 WARN_ON_ONCE(task->tk_timeout != 0);
451 * Protect the queue operations.
454 __rpc_sleep_on_priority(q, task, task->tk_priority);
455 spin_unlock(&q->lock);
457 EXPORT_SYMBOL_GPL(rpc_sleep_on);
459 void rpc_sleep_on_priority_timeout(struct rpc_wait_queue *q,
460 struct rpc_task *task, unsigned long timeout, int priority)
462 if (!rpc_sleep_check_activated(task))
465 priority -= RPC_PRIORITY_LOW;
467 * Protect the queue operations.
470 __rpc_sleep_on_priority_timeout(q, task, timeout, priority);
471 spin_unlock(&q->lock);
473 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority_timeout);
475 void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
478 if (!rpc_sleep_check_activated(task))
481 WARN_ON_ONCE(task->tk_timeout != 0);
482 priority -= RPC_PRIORITY_LOW;
484 * Protect the queue operations.
487 __rpc_sleep_on_priority(q, task, priority);
488 spin_unlock(&q->lock);
490 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority);
493 * __rpc_do_wake_up_task_on_wq - wake up a single rpc_task
494 * @wq: workqueue on which to run task
496 * @task: task to be woken up
498 * Caller must hold queue->lock, and have cleared the task queued flag.
500 static void __rpc_do_wake_up_task_on_wq(struct workqueue_struct *wq,
501 struct rpc_wait_queue *queue,
502 struct rpc_task *task)
504 /* Has the task been executed yet? If not, we cannot wake it up! */
505 if (!RPC_IS_ACTIVATED(task)) {
506 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
510 trace_rpc_task_wakeup(task, queue);
512 __rpc_remove_wait_queue(queue, task);
514 rpc_make_runnable(wq, task);
518 * Wake up a queued task while the queue lock is being held
520 static struct rpc_task *
521 rpc_wake_up_task_on_wq_queue_action_locked(struct workqueue_struct *wq,
522 struct rpc_wait_queue *queue, struct rpc_task *task,
523 bool (*action)(struct rpc_task *, void *), void *data)
525 if (RPC_IS_QUEUED(task)) {
527 if (task->tk_waitqueue == queue) {
528 if (action == NULL || action(task, data)) {
529 __rpc_do_wake_up_task_on_wq(wq, queue, task);
538 * Wake up a queued task while the queue lock is being held
540 static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue,
541 struct rpc_task *task)
543 rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue, queue,
548 * Wake up a task on a specific queue
550 void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
552 if (!RPC_IS_QUEUED(task))
554 spin_lock(&queue->lock);
555 rpc_wake_up_task_queue_locked(queue, task);
556 spin_unlock(&queue->lock);
558 EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
560 static bool rpc_task_action_set_status(struct rpc_task *task, void *status)
562 task->tk_status = *(int *)status;
567 rpc_wake_up_task_queue_set_status_locked(struct rpc_wait_queue *queue,
568 struct rpc_task *task, int status)
570 rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue, queue,
571 task, rpc_task_action_set_status, &status);
575 * rpc_wake_up_queued_task_set_status - wake up a task and set task->tk_status
576 * @queue: pointer to rpc_wait_queue
577 * @task: pointer to rpc_task
578 * @status: integer error value
580 * If @task is queued on @queue, then it is woken up, and @task->tk_status is
581 * set to the value of @status.
584 rpc_wake_up_queued_task_set_status(struct rpc_wait_queue *queue,
585 struct rpc_task *task, int status)
587 if (!RPC_IS_QUEUED(task))
589 spin_lock(&queue->lock);
590 rpc_wake_up_task_queue_set_status_locked(queue, task, status);
591 spin_unlock(&queue->lock);
595 * Wake up the next task on a priority queue.
597 static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *queue)
600 struct rpc_task *task;
603 * Service the privileged queue.
605 q = &queue->tasks[RPC_NR_PRIORITY - 1];
606 if (queue->maxpriority > RPC_PRIORITY_PRIVILEGED && !list_empty(q)) {
607 task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
612 * Service a batch of tasks from a single owner.
614 q = &queue->tasks[queue->priority];
615 if (!list_empty(q) && queue->nr) {
617 task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
622 * Service the next queue.
625 if (q == &queue->tasks[0])
626 q = &queue->tasks[queue->maxpriority];
629 if (!list_empty(q)) {
630 task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
633 } while (q != &queue->tasks[queue->priority]);
635 rpc_reset_waitqueue_priority(queue);
639 rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
644 static struct rpc_task *__rpc_find_next_queued(struct rpc_wait_queue *queue)
646 if (RPC_IS_PRIORITY(queue))
647 return __rpc_find_next_queued_priority(queue);
648 if (!list_empty(&queue->tasks[0]))
649 return list_first_entry(&queue->tasks[0], struct rpc_task, u.tk_wait.list);
654 * Wake up the first task on the wait queue.
656 struct rpc_task *rpc_wake_up_first_on_wq(struct workqueue_struct *wq,
657 struct rpc_wait_queue *queue,
658 bool (*func)(struct rpc_task *, void *), void *data)
660 struct rpc_task *task = NULL;
662 spin_lock(&queue->lock);
663 task = __rpc_find_next_queued(queue);
665 task = rpc_wake_up_task_on_wq_queue_action_locked(wq, queue,
667 spin_unlock(&queue->lock);
673 * Wake up the first task on the wait queue.
675 struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue,
676 bool (*func)(struct rpc_task *, void *), void *data)
678 return rpc_wake_up_first_on_wq(rpciod_workqueue, queue, func, data);
680 EXPORT_SYMBOL_GPL(rpc_wake_up_first);
682 static bool rpc_wake_up_next_func(struct rpc_task *task, void *data)
688 * Wake up the next task on the wait queue.
690 struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *queue)
692 return rpc_wake_up_first(queue, rpc_wake_up_next_func, NULL);
694 EXPORT_SYMBOL_GPL(rpc_wake_up_next);
697 * rpc_wake_up_locked - wake up all rpc_tasks
698 * @queue: rpc_wait_queue on which the tasks are sleeping
701 static void rpc_wake_up_locked(struct rpc_wait_queue *queue)
703 struct rpc_task *task;
706 task = __rpc_find_next_queued(queue);
709 rpc_wake_up_task_queue_locked(queue, task);
714 * rpc_wake_up - wake up all rpc_tasks
715 * @queue: rpc_wait_queue on which the tasks are sleeping
719 void rpc_wake_up(struct rpc_wait_queue *queue)
721 spin_lock(&queue->lock);
722 rpc_wake_up_locked(queue);
723 spin_unlock(&queue->lock);
725 EXPORT_SYMBOL_GPL(rpc_wake_up);
728 * rpc_wake_up_status_locked - wake up all rpc_tasks and set their status value.
729 * @queue: rpc_wait_queue on which the tasks are sleeping
730 * @status: status value to set
732 static void rpc_wake_up_status_locked(struct rpc_wait_queue *queue, int status)
734 struct rpc_task *task;
737 task = __rpc_find_next_queued(queue);
740 rpc_wake_up_task_queue_set_status_locked(queue, task, status);
745 * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
746 * @queue: rpc_wait_queue on which the tasks are sleeping
747 * @status: status value to set
751 void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
753 spin_lock(&queue->lock);
754 rpc_wake_up_status_locked(queue, status);
755 spin_unlock(&queue->lock);
757 EXPORT_SYMBOL_GPL(rpc_wake_up_status);
759 static void __rpc_queue_timer_fn(struct work_struct *work)
761 struct rpc_wait_queue *queue = container_of(work,
762 struct rpc_wait_queue,
763 timer_list.dwork.work);
764 struct rpc_task *task, *n;
765 unsigned long expires, now, timeo;
767 spin_lock(&queue->lock);
768 expires = now = jiffies;
769 list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) {
770 timeo = task->tk_timeout;
771 if (time_after_eq(now, timeo)) {
772 trace_rpc_task_timeout(task, task->tk_action);
773 task->tk_status = -ETIMEDOUT;
774 rpc_wake_up_task_queue_locked(queue, task);
777 if (expires == now || time_after(expires, timeo))
780 if (!list_empty(&queue->timer_list.list))
781 rpc_set_queue_timer(queue, expires);
782 spin_unlock(&queue->lock);
785 static void __rpc_atrun(struct rpc_task *task)
787 if (task->tk_status == -ETIMEDOUT)
792 * Run a task at a later time
794 void rpc_delay(struct rpc_task *task, unsigned long delay)
796 rpc_sleep_on_timeout(&delay_queue, task, __rpc_atrun, jiffies + delay);
798 EXPORT_SYMBOL_GPL(rpc_delay);
801 * Helper to call task->tk_ops->rpc_call_prepare
803 void rpc_prepare_task(struct rpc_task *task)
805 task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
809 rpc_init_task_statistics(struct rpc_task *task)
811 /* Initialize retry counters */
812 task->tk_garb_retry = 2;
813 task->tk_cred_retry = 2;
814 task->tk_rebind_retry = 2;
816 /* starting timestamp */
817 task->tk_start = ktime_get();
821 rpc_reset_task_statistics(struct rpc_task *task)
823 task->tk_timeouts = 0;
824 task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_SENT);
825 rpc_init_task_statistics(task);
829 * Helper that calls task->tk_ops->rpc_call_done if it exists
831 void rpc_exit_task(struct rpc_task *task)
833 trace_rpc_task_end(task, task->tk_action);
834 task->tk_action = NULL;
835 if (task->tk_ops->rpc_count_stats)
836 task->tk_ops->rpc_count_stats(task, task->tk_calldata);
837 else if (task->tk_client)
838 rpc_count_iostats(task, task->tk_client->cl_metrics);
839 if (task->tk_ops->rpc_call_done != NULL) {
840 trace_rpc_task_call_done(task, task->tk_ops->rpc_call_done);
841 task->tk_ops->rpc_call_done(task, task->tk_calldata);
842 if (task->tk_action != NULL) {
843 /* Always release the RPC slot and buffer memory */
845 rpc_reset_task_statistics(task);
850 void rpc_signal_task(struct rpc_task *task)
852 struct rpc_wait_queue *queue;
854 if (!RPC_IS_ACTIVATED(task))
857 trace_rpc_task_signalled(task, task->tk_action);
858 set_bit(RPC_TASK_SIGNALLED, &task->tk_runstate);
859 smp_mb__after_atomic();
860 queue = READ_ONCE(task->tk_waitqueue);
862 rpc_wake_up_queued_task_set_status(queue, task, -ERESTARTSYS);
865 void rpc_exit(struct rpc_task *task, int status)
867 task->tk_status = status;
868 task->tk_action = rpc_exit_task;
869 rpc_wake_up_queued_task(task->tk_waitqueue, task);
871 EXPORT_SYMBOL_GPL(rpc_exit);
873 void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
875 if (ops->rpc_release != NULL)
876 ops->rpc_release(calldata);
880 * This is the RPC `scheduler' (or rather, the finite state machine).
882 static void __rpc_execute(struct rpc_task *task)
884 struct rpc_wait_queue *queue;
885 int task_is_async = RPC_IS_ASYNC(task);
888 WARN_ON_ONCE(RPC_IS_QUEUED(task));
889 if (RPC_IS_QUEUED(task))
893 void (*do_action)(struct rpc_task *);
896 * Perform the next FSM step or a pending callback.
898 * tk_action may be NULL if the task has been killed.
899 * In particular, note that rpc_killall_tasks may
900 * do this at any time, so beware when dereferencing.
902 do_action = task->tk_action;
903 if (task->tk_callback) {
904 do_action = task->tk_callback;
905 task->tk_callback = NULL;
909 trace_rpc_task_run_action(task, do_action);
913 * Lockless check for whether task is sleeping or not.
915 if (!RPC_IS_QUEUED(task)) {
921 * Signalled tasks should exit rather than sleep.
923 if (RPC_SIGNALLED(task)) {
924 task->tk_rpc_status = -ERESTARTSYS;
925 rpc_exit(task, -ERESTARTSYS);
929 * The queue->lock protects against races with
930 * rpc_make_runnable().
932 * Note that once we clear RPC_TASK_RUNNING on an asynchronous
933 * rpc_task, rpc_make_runnable() can assign it to a
934 * different workqueue. We therefore cannot assume that the
935 * rpc_task pointer may still be dereferenced.
937 queue = task->tk_waitqueue;
938 spin_lock(&queue->lock);
939 if (!RPC_IS_QUEUED(task)) {
940 spin_unlock(&queue->lock);
943 rpc_clear_running(task);
944 spin_unlock(&queue->lock);
948 /* sync task: sleep here */
949 trace_rpc_task_sync_sleep(task, task->tk_action);
950 status = out_of_line_wait_on_bit(&task->tk_runstate,
951 RPC_TASK_QUEUED, rpc_wait_bit_killable,
955 * When a sync task receives a signal, it exits with
956 * -ERESTARTSYS. In order to catch any callbacks that
957 * clean up after sleeping on some queue, we don't
958 * break the loop here, but go around once more.
960 trace_rpc_task_signalled(task, task->tk_action);
961 set_bit(RPC_TASK_SIGNALLED, &task->tk_runstate);
962 task->tk_rpc_status = -ERESTARTSYS;
963 rpc_exit(task, -ERESTARTSYS);
965 trace_rpc_task_sync_wake(task, task->tk_action);
968 /* Release all resources associated with the task */
969 rpc_release_task(task);
973 * User-visible entry point to the scheduler.
975 * This may be called recursively if e.g. an async NFS task updates
976 * the attributes and finds that dirty pages must be flushed.
977 * NOTE: Upon exit of this function the task is guaranteed to be
978 * released. In particular note that tk_release() will have
979 * been called, so your task memory may have been freed.
981 void rpc_execute(struct rpc_task *task)
983 bool is_async = RPC_IS_ASYNC(task);
985 rpc_set_active(task);
986 rpc_make_runnable(rpciod_workqueue, task);
988 unsigned int pflags = memalloc_nofs_save();
990 memalloc_nofs_restore(pflags);
994 static void rpc_async_schedule(struct work_struct *work)
996 unsigned int pflags = memalloc_nofs_save();
998 __rpc_execute(container_of(work, struct rpc_task, u.tk_work));
999 memalloc_nofs_restore(pflags);
1003 * rpc_malloc - allocate RPC buffer resources
1006 * A single memory region is allocated, which is split between the
1007 * RPC call and RPC reply that this task is being used for. When
1008 * this RPC is retired, the memory is released by calling rpc_free.
1010 * To prevent rpciod from hanging, this allocator never sleeps,
1011 * returning -ENOMEM and suppressing warning if the request cannot
1012 * be serviced immediately. The caller can arrange to sleep in a
1013 * way that is safe for rpciod.
1015 * Most requests are 'small' (under 2KiB) and can be serviced from a
1016 * mempool, ensuring that NFS reads and writes can always proceed,
1017 * and that there is good locality of reference for these buffers.
1019 int rpc_malloc(struct rpc_task *task)
1021 struct rpc_rqst *rqst = task->tk_rqstp;
1022 size_t size = rqst->rq_callsize + rqst->rq_rcvsize;
1023 struct rpc_buffer *buf;
1024 gfp_t gfp = GFP_NOFS;
1026 if (RPC_IS_SWAPPER(task))
1027 gfp = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
1029 size += sizeof(struct rpc_buffer);
1030 if (size <= RPC_BUFFER_MAXSIZE)
1031 buf = mempool_alloc(rpc_buffer_mempool, gfp);
1033 buf = kmalloc(size, gfp);
1039 rqst->rq_buffer = buf->data;
1040 rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
1043 EXPORT_SYMBOL_GPL(rpc_malloc);
1046 * rpc_free - free RPC buffer resources allocated via rpc_malloc
1050 void rpc_free(struct rpc_task *task)
1052 void *buffer = task->tk_rqstp->rq_buffer;
1054 struct rpc_buffer *buf;
1056 buf = container_of(buffer, struct rpc_buffer, data);
1059 if (size <= RPC_BUFFER_MAXSIZE)
1060 mempool_free(buf, rpc_buffer_mempool);
1064 EXPORT_SYMBOL_GPL(rpc_free);
1067 * Creation and deletion of RPC task structures
1069 static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *task_setup_data)
1071 memset(task, 0, sizeof(*task));
1072 atomic_set(&task->tk_count, 1);
1073 task->tk_flags = task_setup_data->flags;
1074 task->tk_ops = task_setup_data->callback_ops;
1075 task->tk_calldata = task_setup_data->callback_data;
1076 INIT_LIST_HEAD(&task->tk_task);
1078 task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW;
1079 task->tk_owner = current->tgid;
1081 /* Initialize workqueue for async tasks */
1082 task->tk_workqueue = task_setup_data->workqueue;
1084 task->tk_xprt = rpc_task_get_xprt(task_setup_data->rpc_client,
1085 xprt_get(task_setup_data->rpc_xprt));
1087 task->tk_op_cred = get_rpccred(task_setup_data->rpc_op_cred);
1089 if (task->tk_ops->rpc_call_prepare != NULL)
1090 task->tk_action = rpc_prepare_task;
1092 rpc_init_task_statistics(task);
1095 static struct rpc_task *
1096 rpc_alloc_task(void)
1098 return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
1102 * Create a new task for the specified client.
1104 struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
1106 struct rpc_task *task = setup_data->task;
1107 unsigned short flags = 0;
1110 task = rpc_alloc_task();
1111 flags = RPC_TASK_DYNAMIC;
1114 rpc_init_task(task, setup_data);
1115 task->tk_flags |= flags;
1120 * rpc_free_task - release rpc task and perform cleanups
1122 * Note that we free up the rpc_task _after_ rpc_release_calldata()
1123 * in order to work around a workqueue dependency issue.
1126 * "Workqueue currently considers two work items to be the same if they're
1127 * on the same address and won't execute them concurrently - ie. it
1128 * makes a work item which is queued again while being executed wait
1129 * for the previous execution to complete.
1131 * If a work function frees the work item, and then waits for an event
1132 * which should be performed by another work item and *that* work item
1133 * recycles the freed work item, it can create a false dependency loop.
1134 * There really is no reliable way to detect this short of verifying
1135 * every memory free."
1138 static void rpc_free_task(struct rpc_task *task)
1140 unsigned short tk_flags = task->tk_flags;
1142 put_rpccred(task->tk_op_cred);
1143 rpc_release_calldata(task->tk_ops, task->tk_calldata);
1145 if (tk_flags & RPC_TASK_DYNAMIC)
1146 mempool_free(task, rpc_task_mempool);
1149 static void rpc_async_release(struct work_struct *work)
1151 unsigned int pflags = memalloc_nofs_save();
1153 rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
1154 memalloc_nofs_restore(pflags);
1157 static void rpc_release_resources_task(struct rpc_task *task)
1160 if (task->tk_msg.rpc_cred) {
1161 if (!(task->tk_flags & RPC_TASK_CRED_NOREF))
1162 put_cred(task->tk_msg.rpc_cred);
1163 task->tk_msg.rpc_cred = NULL;
1165 rpc_task_release_client(task);
1168 static void rpc_final_put_task(struct rpc_task *task,
1169 struct workqueue_struct *q)
1172 INIT_WORK(&task->u.tk_work, rpc_async_release);
1173 queue_work(q, &task->u.tk_work);
1175 rpc_free_task(task);
1178 static void rpc_do_put_task(struct rpc_task *task, struct workqueue_struct *q)
1180 if (atomic_dec_and_test(&task->tk_count)) {
1181 rpc_release_resources_task(task);
1182 rpc_final_put_task(task, q);
1186 void rpc_put_task(struct rpc_task *task)
1188 rpc_do_put_task(task, NULL);
1190 EXPORT_SYMBOL_GPL(rpc_put_task);
1192 void rpc_put_task_async(struct rpc_task *task)
1194 rpc_do_put_task(task, task->tk_workqueue);
1196 EXPORT_SYMBOL_GPL(rpc_put_task_async);
1198 static void rpc_release_task(struct rpc_task *task)
1200 WARN_ON_ONCE(RPC_IS_QUEUED(task));
1202 rpc_release_resources_task(task);
1205 * Note: at this point we have been removed from rpc_clnt->cl_tasks,
1206 * so it should be safe to use task->tk_count as a test for whether
1207 * or not any other processes still hold references to our rpc_task.
1209 if (atomic_read(&task->tk_count) != 1 + !RPC_IS_ASYNC(task)) {
1210 /* Wake up anyone who may be waiting for task completion */
1211 if (!rpc_complete_task(task))
1214 if (!atomic_dec_and_test(&task->tk_count))
1217 rpc_final_put_task(task, task->tk_workqueue);
1222 return try_module_get(THIS_MODULE) ? 0 : -EINVAL;
1225 void rpciod_down(void)
1227 module_put(THIS_MODULE);
1231 * Start up the rpciod workqueue.
1233 static int rpciod_start(void)
1235 struct workqueue_struct *wq;
1238 * Create the rpciod thread and wait for it to start.
1240 wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
1243 rpciod_workqueue = wq;
1244 wq = alloc_workqueue("xprtiod", WQ_UNBOUND | WQ_MEM_RECLAIM, 0);
1247 xprtiod_workqueue = wq;
1250 wq = rpciod_workqueue;
1251 rpciod_workqueue = NULL;
1252 destroy_workqueue(wq);
1257 static void rpciod_stop(void)
1259 struct workqueue_struct *wq = NULL;
1261 if (rpciod_workqueue == NULL)
1264 wq = rpciod_workqueue;
1265 rpciod_workqueue = NULL;
1266 destroy_workqueue(wq);
1267 wq = xprtiod_workqueue;
1268 xprtiod_workqueue = NULL;
1269 destroy_workqueue(wq);
1273 rpc_destroy_mempool(void)
1276 mempool_destroy(rpc_buffer_mempool);
1277 mempool_destroy(rpc_task_mempool);
1278 kmem_cache_destroy(rpc_task_slabp);
1279 kmem_cache_destroy(rpc_buffer_slabp);
1280 rpc_destroy_wait_queue(&delay_queue);
1284 rpc_init_mempool(void)
1287 * The following is not strictly a mempool initialisation,
1288 * but there is no harm in doing it here
1290 rpc_init_wait_queue(&delay_queue, "delayq");
1291 if (!rpciod_start())
1294 rpc_task_slabp = kmem_cache_create("rpc_tasks",
1295 sizeof(struct rpc_task),
1296 0, SLAB_HWCACHE_ALIGN,
1298 if (!rpc_task_slabp)
1300 rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1302 0, SLAB_HWCACHE_ALIGN,
1304 if (!rpc_buffer_slabp)
1306 rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
1308 if (!rpc_task_mempool)
1310 rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
1312 if (!rpc_buffer_mempool)
1316 rpc_destroy_mempool();