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 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
31 #define RPCDBG_FACILITY RPCDBG_SCHED
34 #define CREATE_TRACE_POINTS
35 #include <trace/events/sunrpc.h>
38 * RPC slabs and memory pools
40 #define RPC_BUFFER_MAXSIZE (2048)
41 #define RPC_BUFFER_POOLSIZE (8)
42 #define RPC_TASK_POOLSIZE (8)
43 static struct kmem_cache *rpc_task_slabp __read_mostly;
44 static struct kmem_cache *rpc_buffer_slabp __read_mostly;
45 static mempool_t *rpc_task_mempool __read_mostly;
46 static mempool_t *rpc_buffer_mempool __read_mostly;
48 static void rpc_async_schedule(struct work_struct *);
49 static void rpc_release_task(struct rpc_task *task);
50 static void __rpc_queue_timer_fn(struct work_struct *);
53 * RPC tasks sit here while waiting for conditions to improve.
55 static struct rpc_wait_queue delay_queue;
58 * rpciod-related stuff
60 struct workqueue_struct *rpciod_workqueue __read_mostly;
61 struct workqueue_struct *xprtiod_workqueue __read_mostly;
62 EXPORT_SYMBOL_GPL(xprtiod_workqueue);
65 rpc_task_timeout(const struct rpc_task *task)
67 unsigned long timeout = READ_ONCE(task->tk_timeout);
70 unsigned long now = jiffies;
71 if (time_before(now, timeout))
76 EXPORT_SYMBOL_GPL(rpc_task_timeout);
79 * Disable the timer for a given RPC task. Should be called with
80 * queue->lock and bh_disabled in order to avoid races within
84 __rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
86 if (list_empty(&task->u.tk_wait.timer_list))
88 dprintk("RPC: %5u disabling timer\n", task->tk_pid);
90 list_del(&task->u.tk_wait.timer_list);
91 if (list_empty(&queue->timer_list.list))
92 cancel_delayed_work(&queue->timer_list.dwork);
96 rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)
98 unsigned long now = jiffies;
99 queue->timer_list.expires = expires;
100 if (time_before_eq(expires, now))
104 mod_delayed_work(rpciod_workqueue, &queue->timer_list.dwork, expires);
108 * Set up a timer for the current task.
111 __rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task,
112 unsigned long timeout)
114 dprintk("RPC: %5u setting alarm for %u ms\n",
115 task->tk_pid, jiffies_to_msecs(timeout - jiffies));
117 task->tk_timeout = timeout;
118 if (list_empty(&queue->timer_list.list) || time_before(timeout, queue->timer_list.expires))
119 rpc_set_queue_timer(queue, timeout);
120 list_add(&task->u.tk_wait.timer_list, &queue->timer_list.list);
123 static void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
125 if (queue->priority != priority) {
126 queue->priority = priority;
127 queue->nr = 1U << priority;
131 static void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
133 rpc_set_waitqueue_priority(queue, queue->maxpriority);
137 * Add a request to a queue list
140 __rpc_list_enqueue_task(struct list_head *q, struct rpc_task *task)
144 list_for_each_entry(t, q, u.tk_wait.list) {
145 if (t->tk_owner == task->tk_owner) {
146 list_add_tail(&task->u.tk_wait.links,
147 &t->u.tk_wait.links);
148 /* Cache the queue head in task->u.tk_wait.list */
149 task->u.tk_wait.list.next = q;
150 task->u.tk_wait.list.prev = NULL;
154 INIT_LIST_HEAD(&task->u.tk_wait.links);
155 list_add_tail(&task->u.tk_wait.list, q);
159 * Remove request from a queue list
162 __rpc_list_dequeue_task(struct rpc_task *task)
167 if (task->u.tk_wait.list.prev == NULL) {
168 list_del(&task->u.tk_wait.links);
171 if (!list_empty(&task->u.tk_wait.links)) {
172 t = list_first_entry(&task->u.tk_wait.links,
175 /* Assume __rpc_list_enqueue_task() cached the queue head */
176 q = t->u.tk_wait.list.next;
177 list_add_tail(&t->u.tk_wait.list, q);
178 list_del(&task->u.tk_wait.links);
180 list_del(&task->u.tk_wait.list);
184 * Add new request to a priority queue.
186 static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue,
187 struct rpc_task *task,
188 unsigned char queue_priority)
190 if (unlikely(queue_priority > queue->maxpriority))
191 queue_priority = queue->maxpriority;
192 __rpc_list_enqueue_task(&queue->tasks[queue_priority], task);
196 * Add new request to wait queue.
198 * Swapper tasks always get inserted at the head of the queue.
199 * This should avoid many nasty memory deadlocks and hopefully
200 * improve overall performance.
201 * Everyone else gets appended to the queue to ensure proper FIFO behavior.
203 static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
204 struct rpc_task *task,
205 unsigned char queue_priority)
207 WARN_ON_ONCE(RPC_IS_QUEUED(task));
208 if (RPC_IS_QUEUED(task))
211 INIT_LIST_HEAD(&task->u.tk_wait.timer_list);
212 if (RPC_IS_PRIORITY(queue))
213 __rpc_add_wait_queue_priority(queue, task, queue_priority);
214 else if (RPC_IS_SWAPPER(task))
215 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
217 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
218 task->tk_waitqueue = queue;
220 /* barrier matches the read in rpc_wake_up_task_queue_locked() */
222 rpc_set_queued(task);
224 dprintk("RPC: %5u added to queue %p \"%s\"\n",
225 task->tk_pid, queue, rpc_qname(queue));
229 * Remove request from a priority queue.
231 static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
233 __rpc_list_dequeue_task(task);
237 * Remove request from queue.
238 * Note: must be called with spin lock held.
240 static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
242 __rpc_disable_timer(queue, task);
243 if (RPC_IS_PRIORITY(queue))
244 __rpc_remove_wait_queue_priority(task);
246 list_del(&task->u.tk_wait.list);
248 dprintk("RPC: %5u removed from queue %p \"%s\"\n",
249 task->tk_pid, queue, rpc_qname(queue));
252 static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
256 spin_lock_init(&queue->lock);
257 for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
258 INIT_LIST_HEAD(&queue->tasks[i]);
259 queue->maxpriority = nr_queues - 1;
260 rpc_reset_waitqueue_priority(queue);
262 queue->timer_list.expires = 0;
263 INIT_DEFERRABLE_WORK(&queue->timer_list.dwork, __rpc_queue_timer_fn);
264 INIT_LIST_HEAD(&queue->timer_list.list);
265 rpc_assign_waitqueue_name(queue, qname);
268 void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
270 __rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY);
272 EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue);
274 void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
276 __rpc_init_priority_wait_queue(queue, qname, 1);
278 EXPORT_SYMBOL_GPL(rpc_init_wait_queue);
280 void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)
282 cancel_delayed_work_sync(&queue->timer_list.dwork);
284 EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
286 static int rpc_wait_bit_killable(struct wait_bit_key *key, int mode)
288 freezable_schedule_unsafe();
289 if (signal_pending_state(mode, current))
294 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS)
295 static void rpc_task_set_debuginfo(struct rpc_task *task)
297 static atomic_t rpc_pid;
299 task->tk_pid = atomic_inc_return(&rpc_pid);
302 static inline void rpc_task_set_debuginfo(struct rpc_task *task)
307 static void rpc_set_active(struct rpc_task *task)
309 rpc_task_set_debuginfo(task);
310 set_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
311 trace_rpc_task_begin(task, NULL);
315 * Mark an RPC call as having completed by clearing the 'active' bit
316 * and then waking up all tasks that were sleeping.
318 static int rpc_complete_task(struct rpc_task *task)
320 void *m = &task->tk_runstate;
321 wait_queue_head_t *wq = bit_waitqueue(m, RPC_TASK_ACTIVE);
322 struct wait_bit_key k = __WAIT_BIT_KEY_INITIALIZER(m, RPC_TASK_ACTIVE);
326 trace_rpc_task_complete(task, NULL);
328 spin_lock_irqsave(&wq->lock, flags);
329 clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
330 ret = atomic_dec_and_test(&task->tk_count);
331 if (waitqueue_active(wq))
332 __wake_up_locked_key(wq, TASK_NORMAL, &k);
333 spin_unlock_irqrestore(&wq->lock, flags);
338 * Allow callers to wait for completion of an RPC call
340 * Note the use of out_of_line_wait_on_bit() rather than wait_on_bit()
341 * to enforce taking of the wq->lock and hence avoid races with
342 * rpc_complete_task().
344 int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *action)
347 action = rpc_wait_bit_killable;
348 return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
349 action, TASK_KILLABLE);
351 EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
354 * Make an RPC task runnable.
356 * Note: If the task is ASYNC, and is being made runnable after sitting on an
357 * rpc_wait_queue, this must be called with the queue spinlock held to protect
358 * the wait queue operation.
359 * Note the ordering of rpc_test_and_set_running() and rpc_clear_queued(),
360 * which is needed to ensure that __rpc_execute() doesn't loop (due to the
361 * lockless RPC_IS_QUEUED() test) before we've had a chance to test
362 * the RPC_TASK_RUNNING flag.
364 static void rpc_make_runnable(struct workqueue_struct *wq,
365 struct rpc_task *task)
367 bool need_wakeup = !rpc_test_and_set_running(task);
369 rpc_clear_queued(task);
372 if (RPC_IS_ASYNC(task)) {
373 INIT_WORK(&task->u.tk_work, rpc_async_schedule);
374 queue_work(wq, &task->u.tk_work);
376 wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
380 * Prepare for sleeping on a wait queue.
381 * By always appending tasks to the list we ensure FIFO behavior.
382 * NB: An RPC task will only receive interrupt-driven events as long
383 * as it's on a wait queue.
385 static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
386 struct rpc_task *task,
387 unsigned char queue_priority)
389 dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n",
390 task->tk_pid, rpc_qname(q), jiffies);
392 trace_rpc_task_sleep(task, q);
394 __rpc_add_wait_queue(q, task, queue_priority);
398 static void __rpc_sleep_on_priority_timeout(struct rpc_wait_queue *q,
399 struct rpc_task *task, unsigned long timeout,
400 unsigned char queue_priority)
402 if (time_is_after_jiffies(timeout)) {
403 __rpc_sleep_on_priority(q, task, queue_priority);
404 __rpc_add_timer(q, task, timeout);
406 task->tk_status = -ETIMEDOUT;
409 static void rpc_set_tk_callback(struct rpc_task *task, rpc_action action)
411 if (action && !WARN_ON_ONCE(task->tk_callback != NULL))
412 task->tk_callback = action;
415 static bool rpc_sleep_check_activated(struct rpc_task *task)
417 /* We shouldn't ever put an inactive task to sleep */
418 if (WARN_ON_ONCE(!RPC_IS_ACTIVATED(task))) {
419 task->tk_status = -EIO;
420 rpc_put_task_async(task);
426 void rpc_sleep_on_timeout(struct rpc_wait_queue *q, struct rpc_task *task,
427 rpc_action action, unsigned long timeout)
429 if (!rpc_sleep_check_activated(task))
432 rpc_set_tk_callback(task, action);
435 * Protect the queue operations.
438 __rpc_sleep_on_priority_timeout(q, task, timeout, task->tk_priority);
439 spin_unlock(&q->lock);
441 EXPORT_SYMBOL_GPL(rpc_sleep_on_timeout);
443 void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
446 if (!rpc_sleep_check_activated(task))
449 rpc_set_tk_callback(task, action);
451 WARN_ON_ONCE(task->tk_timeout != 0);
453 * Protect the queue operations.
456 __rpc_sleep_on_priority(q, task, task->tk_priority);
457 spin_unlock(&q->lock);
459 EXPORT_SYMBOL_GPL(rpc_sleep_on);
461 void rpc_sleep_on_priority_timeout(struct rpc_wait_queue *q,
462 struct rpc_task *task, unsigned long timeout, int priority)
464 if (!rpc_sleep_check_activated(task))
467 priority -= RPC_PRIORITY_LOW;
469 * Protect the queue operations.
472 __rpc_sleep_on_priority_timeout(q, task, timeout, priority);
473 spin_unlock(&q->lock);
475 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority_timeout);
477 void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
480 if (!rpc_sleep_check_activated(task))
483 WARN_ON_ONCE(task->tk_timeout != 0);
484 priority -= RPC_PRIORITY_LOW;
486 * Protect the queue operations.
489 __rpc_sleep_on_priority(q, task, priority);
490 spin_unlock(&q->lock);
492 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority);
495 * __rpc_do_wake_up_task_on_wq - wake up a single rpc_task
496 * @wq: workqueue on which to run task
498 * @task: task to be woken up
500 * Caller must hold queue->lock, and have cleared the task queued flag.
502 static void __rpc_do_wake_up_task_on_wq(struct workqueue_struct *wq,
503 struct rpc_wait_queue *queue,
504 struct rpc_task *task)
506 dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
507 task->tk_pid, jiffies);
509 /* Has the task been executed yet? If not, we cannot wake it up! */
510 if (!RPC_IS_ACTIVATED(task)) {
511 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
515 trace_rpc_task_wakeup(task, queue);
517 __rpc_remove_wait_queue(queue, task);
519 rpc_make_runnable(wq, task);
521 dprintk("RPC: __rpc_wake_up_task done\n");
525 * Wake up a queued task while the queue lock is being held
527 static struct rpc_task *
528 rpc_wake_up_task_on_wq_queue_action_locked(struct workqueue_struct *wq,
529 struct rpc_wait_queue *queue, struct rpc_task *task,
530 bool (*action)(struct rpc_task *, void *), void *data)
532 if (RPC_IS_QUEUED(task)) {
534 if (task->tk_waitqueue == queue) {
535 if (action == NULL || action(task, data)) {
536 __rpc_do_wake_up_task_on_wq(wq, queue, task);
545 rpc_wake_up_task_on_wq_queue_locked(struct workqueue_struct *wq,
546 struct rpc_wait_queue *queue, struct rpc_task *task)
548 rpc_wake_up_task_on_wq_queue_action_locked(wq, queue, task, NULL, NULL);
552 * Wake up a queued task while the queue lock is being held
554 static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
556 rpc_wake_up_task_on_wq_queue_locked(rpciod_workqueue, queue, task);
560 * Wake up a task on a specific queue
562 void rpc_wake_up_queued_task_on_wq(struct workqueue_struct *wq,
563 struct rpc_wait_queue *queue,
564 struct rpc_task *task)
566 if (!RPC_IS_QUEUED(task))
568 spin_lock(&queue->lock);
569 rpc_wake_up_task_on_wq_queue_locked(wq, queue, task);
570 spin_unlock(&queue->lock);
574 * Wake up a task on a specific queue
576 void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
578 if (!RPC_IS_QUEUED(task))
580 spin_lock(&queue->lock);
581 rpc_wake_up_task_queue_locked(queue, task);
582 spin_unlock(&queue->lock);
584 EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
586 static bool rpc_task_action_set_status(struct rpc_task *task, void *status)
588 task->tk_status = *(int *)status;
593 rpc_wake_up_task_queue_set_status_locked(struct rpc_wait_queue *queue,
594 struct rpc_task *task, int status)
596 rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue, queue,
597 task, rpc_task_action_set_status, &status);
601 * rpc_wake_up_queued_task_set_status - wake up a task and set task->tk_status
602 * @queue: pointer to rpc_wait_queue
603 * @task: pointer to rpc_task
604 * @status: integer error value
606 * If @task is queued on @queue, then it is woken up, and @task->tk_status is
607 * set to the value of @status.
610 rpc_wake_up_queued_task_set_status(struct rpc_wait_queue *queue,
611 struct rpc_task *task, int status)
613 if (!RPC_IS_QUEUED(task))
615 spin_lock(&queue->lock);
616 rpc_wake_up_task_queue_set_status_locked(queue, task, status);
617 spin_unlock(&queue->lock);
621 * Wake up the next task on a priority queue.
623 static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *queue)
626 struct rpc_task *task;
629 * Service a batch of tasks from a single owner.
631 q = &queue->tasks[queue->priority];
632 if (!list_empty(q) && --queue->nr) {
633 task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
638 * Service the next queue.
641 if (q == &queue->tasks[0])
642 q = &queue->tasks[queue->maxpriority];
645 if (!list_empty(q)) {
646 task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
649 } while (q != &queue->tasks[queue->priority]);
651 rpc_reset_waitqueue_priority(queue);
655 rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
660 static struct rpc_task *__rpc_find_next_queued(struct rpc_wait_queue *queue)
662 if (RPC_IS_PRIORITY(queue))
663 return __rpc_find_next_queued_priority(queue);
664 if (!list_empty(&queue->tasks[0]))
665 return list_first_entry(&queue->tasks[0], struct rpc_task, u.tk_wait.list);
670 * Wake up the first task on the wait queue.
672 struct rpc_task *rpc_wake_up_first_on_wq(struct workqueue_struct *wq,
673 struct rpc_wait_queue *queue,
674 bool (*func)(struct rpc_task *, void *), void *data)
676 struct rpc_task *task = NULL;
678 dprintk("RPC: wake_up_first(%p \"%s\")\n",
679 queue, rpc_qname(queue));
680 spin_lock(&queue->lock);
681 task = __rpc_find_next_queued(queue);
683 task = rpc_wake_up_task_on_wq_queue_action_locked(wq, queue,
685 spin_unlock(&queue->lock);
691 * Wake up the first task on the wait queue.
693 struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue,
694 bool (*func)(struct rpc_task *, void *), void *data)
696 return rpc_wake_up_first_on_wq(rpciod_workqueue, queue, func, data);
698 EXPORT_SYMBOL_GPL(rpc_wake_up_first);
700 static bool rpc_wake_up_next_func(struct rpc_task *task, void *data)
706 * Wake up the next task on the wait queue.
708 struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *queue)
710 return rpc_wake_up_first(queue, rpc_wake_up_next_func, NULL);
712 EXPORT_SYMBOL_GPL(rpc_wake_up_next);
715 * rpc_wake_up - wake up all rpc_tasks
716 * @queue: rpc_wait_queue on which the tasks are sleeping
720 void rpc_wake_up(struct rpc_wait_queue *queue)
722 struct list_head *head;
724 spin_lock(&queue->lock);
725 head = &queue->tasks[queue->maxpriority];
727 while (!list_empty(head)) {
728 struct rpc_task *task;
729 task = list_first_entry(head,
732 rpc_wake_up_task_queue_locked(queue, task);
734 if (head == &queue->tasks[0])
738 spin_unlock(&queue->lock);
740 EXPORT_SYMBOL_GPL(rpc_wake_up);
743 * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
744 * @queue: rpc_wait_queue on which the tasks are sleeping
745 * @status: status value to set
749 void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
751 struct list_head *head;
753 spin_lock(&queue->lock);
754 head = &queue->tasks[queue->maxpriority];
756 while (!list_empty(head)) {
757 struct rpc_task *task;
758 task = list_first_entry(head,
761 task->tk_status = status;
762 rpc_wake_up_task_queue_locked(queue, task);
764 if (head == &queue->tasks[0])
768 spin_unlock(&queue->lock);
770 EXPORT_SYMBOL_GPL(rpc_wake_up_status);
772 static void __rpc_queue_timer_fn(struct work_struct *work)
774 struct rpc_wait_queue *queue = container_of(work,
775 struct rpc_wait_queue,
776 timer_list.dwork.work);
777 struct rpc_task *task, *n;
778 unsigned long expires, now, timeo;
780 spin_lock(&queue->lock);
781 expires = now = jiffies;
782 list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) {
783 timeo = task->tk_timeout;
784 if (time_after_eq(now, timeo)) {
785 dprintk("RPC: %5u timeout\n", task->tk_pid);
786 task->tk_status = -ETIMEDOUT;
787 rpc_wake_up_task_queue_locked(queue, task);
790 if (expires == now || time_after(expires, timeo))
793 if (!list_empty(&queue->timer_list.list))
794 rpc_set_queue_timer(queue, expires);
795 spin_unlock(&queue->lock);
798 static void __rpc_atrun(struct rpc_task *task)
800 if (task->tk_status == -ETIMEDOUT)
805 * Run a task at a later time
807 void rpc_delay(struct rpc_task *task, unsigned long delay)
809 rpc_sleep_on_timeout(&delay_queue, task, __rpc_atrun, jiffies + delay);
811 EXPORT_SYMBOL_GPL(rpc_delay);
814 * Helper to call task->tk_ops->rpc_call_prepare
816 void rpc_prepare_task(struct rpc_task *task)
818 task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
822 rpc_init_task_statistics(struct rpc_task *task)
824 /* Initialize retry counters */
825 task->tk_garb_retry = 2;
826 task->tk_cred_retry = 2;
827 task->tk_rebind_retry = 2;
829 /* starting timestamp */
830 task->tk_start = ktime_get();
834 rpc_reset_task_statistics(struct rpc_task *task)
836 task->tk_timeouts = 0;
837 task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_SENT);
838 rpc_init_task_statistics(task);
842 * Helper that calls task->tk_ops->rpc_call_done if it exists
844 void rpc_exit_task(struct rpc_task *task)
846 task->tk_action = NULL;
847 if (task->tk_ops->rpc_count_stats)
848 task->tk_ops->rpc_count_stats(task, task->tk_calldata);
849 else if (task->tk_client)
850 rpc_count_iostats(task, task->tk_client->cl_metrics);
851 if (task->tk_ops->rpc_call_done != NULL) {
852 task->tk_ops->rpc_call_done(task, task->tk_calldata);
853 if (task->tk_action != NULL) {
854 /* Always release the RPC slot and buffer memory */
856 rpc_reset_task_statistics(task);
861 void rpc_signal_task(struct rpc_task *task)
863 struct rpc_wait_queue *queue;
865 if (!RPC_IS_ACTIVATED(task))
867 set_bit(RPC_TASK_SIGNALLED, &task->tk_runstate);
868 smp_mb__after_atomic();
869 queue = READ_ONCE(task->tk_waitqueue);
871 rpc_wake_up_queued_task_set_status(queue, task, -ERESTARTSYS);
874 void rpc_exit(struct rpc_task *task, int status)
876 task->tk_status = status;
877 task->tk_action = rpc_exit_task;
878 rpc_wake_up_queued_task(task->tk_waitqueue, task);
880 EXPORT_SYMBOL_GPL(rpc_exit);
882 void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
884 if (ops->rpc_release != NULL)
885 ops->rpc_release(calldata);
889 * This is the RPC `scheduler' (or rather, the finite state machine).
891 static void __rpc_execute(struct rpc_task *task)
893 struct rpc_wait_queue *queue;
894 int task_is_async = RPC_IS_ASYNC(task);
897 dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
898 task->tk_pid, task->tk_flags);
900 WARN_ON_ONCE(RPC_IS_QUEUED(task));
901 if (RPC_IS_QUEUED(task))
905 void (*do_action)(struct rpc_task *);
908 * Perform the next FSM step or a pending callback.
910 * tk_action may be NULL if the task has been killed.
911 * In particular, note that rpc_killall_tasks may
912 * do this at any time, so beware when dereferencing.
914 do_action = task->tk_action;
915 if (task->tk_callback) {
916 do_action = task->tk_callback;
917 task->tk_callback = NULL;
921 trace_rpc_task_run_action(task, do_action);
925 * Lockless check for whether task is sleeping or not.
927 if (!RPC_IS_QUEUED(task))
931 * Signalled tasks should exit rather than sleep.
933 if (RPC_SIGNALLED(task)) {
934 task->tk_rpc_status = -ERESTARTSYS;
935 rpc_exit(task, -ERESTARTSYS);
939 * The queue->lock protects against races with
940 * rpc_make_runnable().
942 * Note that once we clear RPC_TASK_RUNNING on an asynchronous
943 * rpc_task, rpc_make_runnable() can assign it to a
944 * different workqueue. We therefore cannot assume that the
945 * rpc_task pointer may still be dereferenced.
947 queue = task->tk_waitqueue;
948 spin_lock(&queue->lock);
949 if (!RPC_IS_QUEUED(task)) {
950 spin_unlock(&queue->lock);
953 rpc_clear_running(task);
954 spin_unlock(&queue->lock);
958 /* sync task: sleep here */
959 dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid);
960 status = out_of_line_wait_on_bit(&task->tk_runstate,
961 RPC_TASK_QUEUED, rpc_wait_bit_killable,
965 * When a sync task receives a signal, it exits with
966 * -ERESTARTSYS. In order to catch any callbacks that
967 * clean up after sleeping on some queue, we don't
968 * break the loop here, but go around once more.
970 dprintk("RPC: %5u got signal\n", task->tk_pid);
971 set_bit(RPC_TASK_SIGNALLED, &task->tk_runstate);
972 task->tk_rpc_status = -ERESTARTSYS;
973 rpc_exit(task, -ERESTARTSYS);
975 dprintk("RPC: %5u sync task resuming\n", task->tk_pid);
978 dprintk("RPC: %5u return %d, status %d\n", task->tk_pid, status,
980 /* Release all resources associated with the task */
981 rpc_release_task(task);
985 * User-visible entry point to the scheduler.
987 * This may be called recursively if e.g. an async NFS task updates
988 * the attributes and finds that dirty pages must be flushed.
989 * NOTE: Upon exit of this function the task is guaranteed to be
990 * released. In particular note that tk_release() will have
991 * been called, so your task memory may have been freed.
993 void rpc_execute(struct rpc_task *task)
995 bool is_async = RPC_IS_ASYNC(task);
997 rpc_set_active(task);
998 rpc_make_runnable(rpciod_workqueue, task);
1000 __rpc_execute(task);
1003 static void rpc_async_schedule(struct work_struct *work)
1005 unsigned int pflags = memalloc_nofs_save();
1007 __rpc_execute(container_of(work, struct rpc_task, u.tk_work));
1008 memalloc_nofs_restore(pflags);
1012 * rpc_malloc - allocate RPC buffer resources
1015 * A single memory region is allocated, which is split between the
1016 * RPC call and RPC reply that this task is being used for. When
1017 * this RPC is retired, the memory is released by calling rpc_free.
1019 * To prevent rpciod from hanging, this allocator never sleeps,
1020 * returning -ENOMEM and suppressing warning if the request cannot
1021 * be serviced immediately. The caller can arrange to sleep in a
1022 * way that is safe for rpciod.
1024 * Most requests are 'small' (under 2KiB) and can be serviced from a
1025 * mempool, ensuring that NFS reads and writes can always proceed,
1026 * and that there is good locality of reference for these buffers.
1028 int rpc_malloc(struct rpc_task *task)
1030 struct rpc_rqst *rqst = task->tk_rqstp;
1031 size_t size = rqst->rq_callsize + rqst->rq_rcvsize;
1032 struct rpc_buffer *buf;
1033 gfp_t gfp = GFP_NOFS;
1035 if (RPC_IS_SWAPPER(task))
1036 gfp = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
1038 size += sizeof(struct rpc_buffer);
1039 if (size <= RPC_BUFFER_MAXSIZE)
1040 buf = mempool_alloc(rpc_buffer_mempool, gfp);
1042 buf = kmalloc(size, gfp);
1048 dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
1049 task->tk_pid, size, buf);
1050 rqst->rq_buffer = buf->data;
1051 rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
1054 EXPORT_SYMBOL_GPL(rpc_malloc);
1057 * rpc_free - free RPC buffer resources allocated via rpc_malloc
1061 void rpc_free(struct rpc_task *task)
1063 void *buffer = task->tk_rqstp->rq_buffer;
1065 struct rpc_buffer *buf;
1067 buf = container_of(buffer, struct rpc_buffer, data);
1070 dprintk("RPC: freeing buffer of size %zu at %p\n",
1073 if (size <= RPC_BUFFER_MAXSIZE)
1074 mempool_free(buf, rpc_buffer_mempool);
1078 EXPORT_SYMBOL_GPL(rpc_free);
1081 * Creation and deletion of RPC task structures
1083 static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *task_setup_data)
1085 memset(task, 0, sizeof(*task));
1086 atomic_set(&task->tk_count, 1);
1087 task->tk_flags = task_setup_data->flags;
1088 task->tk_ops = task_setup_data->callback_ops;
1089 task->tk_calldata = task_setup_data->callback_data;
1090 INIT_LIST_HEAD(&task->tk_task);
1092 task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW;
1093 task->tk_owner = current->tgid;
1095 /* Initialize workqueue for async tasks */
1096 task->tk_workqueue = task_setup_data->workqueue;
1098 task->tk_xprt = rpc_task_get_xprt(task_setup_data->rpc_client,
1099 xprt_get(task_setup_data->rpc_xprt));
1101 task->tk_op_cred = get_rpccred(task_setup_data->rpc_op_cred);
1103 if (task->tk_ops->rpc_call_prepare != NULL)
1104 task->tk_action = rpc_prepare_task;
1106 rpc_init_task_statistics(task);
1108 dprintk("RPC: new task initialized, procpid %u\n",
1109 task_pid_nr(current));
1112 static struct rpc_task *
1113 rpc_alloc_task(void)
1115 return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
1119 * Create a new task for the specified client.
1121 struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
1123 struct rpc_task *task = setup_data->task;
1124 unsigned short flags = 0;
1127 task = rpc_alloc_task();
1128 flags = RPC_TASK_DYNAMIC;
1131 rpc_init_task(task, setup_data);
1132 task->tk_flags |= flags;
1133 dprintk("RPC: allocated task %p\n", task);
1138 * rpc_free_task - release rpc task and perform cleanups
1140 * Note that we free up the rpc_task _after_ rpc_release_calldata()
1141 * in order to work around a workqueue dependency issue.
1144 * "Workqueue currently considers two work items to be the same if they're
1145 * on the same address and won't execute them concurrently - ie. it
1146 * makes a work item which is queued again while being executed wait
1147 * for the previous execution to complete.
1149 * If a work function frees the work item, and then waits for an event
1150 * which should be performed by another work item and *that* work item
1151 * recycles the freed work item, it can create a false dependency loop.
1152 * There really is no reliable way to detect this short of verifying
1153 * every memory free."
1156 static void rpc_free_task(struct rpc_task *task)
1158 unsigned short tk_flags = task->tk_flags;
1160 put_rpccred(task->tk_op_cred);
1161 rpc_release_calldata(task->tk_ops, task->tk_calldata);
1163 if (tk_flags & RPC_TASK_DYNAMIC) {
1164 dprintk("RPC: %5u freeing task\n", task->tk_pid);
1165 mempool_free(task, rpc_task_mempool);
1169 static void rpc_async_release(struct work_struct *work)
1171 unsigned int pflags = memalloc_nofs_save();
1173 rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
1174 memalloc_nofs_restore(pflags);
1177 static void rpc_release_resources_task(struct rpc_task *task)
1180 if (task->tk_msg.rpc_cred) {
1181 put_cred(task->tk_msg.rpc_cred);
1182 task->tk_msg.rpc_cred = NULL;
1184 rpc_task_release_client(task);
1187 static void rpc_final_put_task(struct rpc_task *task,
1188 struct workqueue_struct *q)
1191 INIT_WORK(&task->u.tk_work, rpc_async_release);
1192 queue_work(q, &task->u.tk_work);
1194 rpc_free_task(task);
1197 static void rpc_do_put_task(struct rpc_task *task, struct workqueue_struct *q)
1199 if (atomic_dec_and_test(&task->tk_count)) {
1200 rpc_release_resources_task(task);
1201 rpc_final_put_task(task, q);
1205 void rpc_put_task(struct rpc_task *task)
1207 rpc_do_put_task(task, NULL);
1209 EXPORT_SYMBOL_GPL(rpc_put_task);
1211 void rpc_put_task_async(struct rpc_task *task)
1213 rpc_do_put_task(task, task->tk_workqueue);
1215 EXPORT_SYMBOL_GPL(rpc_put_task_async);
1217 static void rpc_release_task(struct rpc_task *task)
1219 dprintk("RPC: %5u release task\n", task->tk_pid);
1221 WARN_ON_ONCE(RPC_IS_QUEUED(task));
1223 rpc_release_resources_task(task);
1226 * Note: at this point we have been removed from rpc_clnt->cl_tasks,
1227 * so it should be safe to use task->tk_count as a test for whether
1228 * or not any other processes still hold references to our rpc_task.
1230 if (atomic_read(&task->tk_count) != 1 + !RPC_IS_ASYNC(task)) {
1231 /* Wake up anyone who may be waiting for task completion */
1232 if (!rpc_complete_task(task))
1235 if (!atomic_dec_and_test(&task->tk_count))
1238 rpc_final_put_task(task, task->tk_workqueue);
1243 return try_module_get(THIS_MODULE) ? 0 : -EINVAL;
1246 void rpciod_down(void)
1248 module_put(THIS_MODULE);
1252 * Start up the rpciod workqueue.
1254 static int rpciod_start(void)
1256 struct workqueue_struct *wq;
1259 * Create the rpciod thread and wait for it to start.
1261 dprintk("RPC: creating workqueue rpciod\n");
1262 wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
1265 rpciod_workqueue = wq;
1266 /* Note: highpri because network receive is latency sensitive */
1267 wq = alloc_workqueue("xprtiod", WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_HIGHPRI, 0);
1270 xprtiod_workqueue = wq;
1273 wq = rpciod_workqueue;
1274 rpciod_workqueue = NULL;
1275 destroy_workqueue(wq);
1280 static void rpciod_stop(void)
1282 struct workqueue_struct *wq = NULL;
1284 if (rpciod_workqueue == NULL)
1286 dprintk("RPC: destroying workqueue rpciod\n");
1288 wq = rpciod_workqueue;
1289 rpciod_workqueue = NULL;
1290 destroy_workqueue(wq);
1291 wq = xprtiod_workqueue;
1292 xprtiod_workqueue = NULL;
1293 destroy_workqueue(wq);
1297 rpc_destroy_mempool(void)
1300 mempool_destroy(rpc_buffer_mempool);
1301 mempool_destroy(rpc_task_mempool);
1302 kmem_cache_destroy(rpc_task_slabp);
1303 kmem_cache_destroy(rpc_buffer_slabp);
1304 rpc_destroy_wait_queue(&delay_queue);
1308 rpc_init_mempool(void)
1311 * The following is not strictly a mempool initialisation,
1312 * but there is no harm in doing it here
1314 rpc_init_wait_queue(&delay_queue, "delayq");
1315 if (!rpciod_start())
1318 rpc_task_slabp = kmem_cache_create("rpc_tasks",
1319 sizeof(struct rpc_task),
1320 0, SLAB_HWCACHE_ALIGN,
1322 if (!rpc_task_slabp)
1324 rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1326 0, SLAB_HWCACHE_ALIGN,
1328 if (!rpc_buffer_slabp)
1330 rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
1332 if (!rpc_task_mempool)
1334 rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
1336 if (!rpc_buffer_mempool)
1340 rpc_destroy_mempool();