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 static atomic_t rpc_pid
;
282 task
->tk_pid
= atomic_inc_return(&rpc_pid
);
285 static inline void rpc_task_set_debuginfo(struct rpc_task
*task
)
290 static void rpc_set_active(struct rpc_task
*task
)
292 rpc_task_set_debuginfo(task
);
293 set_bit(RPC_TASK_ACTIVE
, &task
->tk_runstate
);
294 trace_rpc_task_begin(task
, NULL
);
298 * Mark an RPC call as having completed by clearing the 'active' bit
299 * and then waking up all tasks that were sleeping.
301 static int rpc_complete_task(struct rpc_task
*task
)
303 void *m
= &task
->tk_runstate
;
304 wait_queue_head_t
*wq
= bit_waitqueue(m
, RPC_TASK_ACTIVE
);
305 struct wait_bit_key k
= __WAIT_BIT_KEY_INITIALIZER(m
, RPC_TASK_ACTIVE
);
309 trace_rpc_task_complete(task
, NULL
);
311 spin_lock_irqsave(&wq
->lock
, flags
);
312 clear_bit(RPC_TASK_ACTIVE
, &task
->tk_runstate
);
313 ret
= atomic_dec_and_test(&task
->tk_count
);
314 if (waitqueue_active(wq
))
315 __wake_up_locked_key(wq
, TASK_NORMAL
, &k
);
316 spin_unlock_irqrestore(&wq
->lock
, flags
);
321 * Allow callers to wait for completion of an RPC call
323 * Note the use of out_of_line_wait_on_bit() rather than wait_on_bit()
324 * to enforce taking of the wq->lock and hence avoid races with
325 * rpc_complete_task().
327 int __rpc_wait_for_completion_task(struct rpc_task
*task
, wait_bit_action_f
*action
)
330 action
= rpc_wait_bit_killable
;
331 return out_of_line_wait_on_bit(&task
->tk_runstate
, RPC_TASK_ACTIVE
,
332 action
, TASK_KILLABLE
);
334 EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task
);
337 * Make an RPC task runnable.
339 * Note: If the task is ASYNC, and is being made runnable after sitting on an
340 * rpc_wait_queue, this must be called with the queue spinlock held to protect
341 * the wait queue operation.
342 * Note the ordering of rpc_test_and_set_running() and rpc_clear_queued(),
343 * which is needed to ensure that __rpc_execute() doesn't loop (due to the
344 * lockless RPC_IS_QUEUED() test) before we've had a chance to test
345 * the RPC_TASK_RUNNING flag.
347 static void rpc_make_runnable(struct workqueue_struct
*wq
,
348 struct rpc_task
*task
)
350 bool need_wakeup
= !rpc_test_and_set_running(task
);
352 rpc_clear_queued(task
);
355 if (RPC_IS_ASYNC(task
)) {
356 INIT_WORK(&task
->u
.tk_work
, rpc_async_schedule
);
357 queue_work(wq
, &task
->u
.tk_work
);
359 wake_up_bit(&task
->tk_runstate
, RPC_TASK_QUEUED
);
363 * Prepare for sleeping on a wait queue.
364 * By always appending tasks to the list we ensure FIFO behavior.
365 * NB: An RPC task will only receive interrupt-driven events as long
366 * as it's on a wait queue.
368 static void __rpc_do_sleep_on_priority(struct rpc_wait_queue
*q
,
369 struct rpc_task
*task
,
370 unsigned char queue_priority
)
372 trace_rpc_task_sleep(task
, q
);
374 __rpc_add_wait_queue(q
, task
, queue_priority
);
377 static void __rpc_sleep_on_priority(struct rpc_wait_queue
*q
,
378 struct rpc_task
*task
,
379 unsigned char queue_priority
)
381 if (WARN_ON_ONCE(RPC_IS_QUEUED(task
)))
383 __rpc_do_sleep_on_priority(q
, task
, queue_priority
);
386 static void __rpc_sleep_on_priority_timeout(struct rpc_wait_queue
*q
,
387 struct rpc_task
*task
, unsigned long timeout
,
388 unsigned char queue_priority
)
390 if (WARN_ON_ONCE(RPC_IS_QUEUED(task
)))
392 if (time_is_after_jiffies(timeout
)) {
393 __rpc_do_sleep_on_priority(q
, task
, queue_priority
);
394 __rpc_add_timer(q
, task
, timeout
);
396 task
->tk_status
= -ETIMEDOUT
;
399 static void rpc_set_tk_callback(struct rpc_task
*task
, rpc_action action
)
401 if (action
&& !WARN_ON_ONCE(task
->tk_callback
!= NULL
))
402 task
->tk_callback
= action
;
405 static bool rpc_sleep_check_activated(struct rpc_task
*task
)
407 /* We shouldn't ever put an inactive task to sleep */
408 if (WARN_ON_ONCE(!RPC_IS_ACTIVATED(task
))) {
409 task
->tk_status
= -EIO
;
410 rpc_put_task_async(task
);
416 void rpc_sleep_on_timeout(struct rpc_wait_queue
*q
, struct rpc_task
*task
,
417 rpc_action action
, unsigned long timeout
)
419 if (!rpc_sleep_check_activated(task
))
422 rpc_set_tk_callback(task
, action
);
425 * Protect the queue operations.
428 __rpc_sleep_on_priority_timeout(q
, task
, timeout
, task
->tk_priority
);
429 spin_unlock(&q
->lock
);
431 EXPORT_SYMBOL_GPL(rpc_sleep_on_timeout
);
433 void rpc_sleep_on(struct rpc_wait_queue
*q
, struct rpc_task
*task
,
436 if (!rpc_sleep_check_activated(task
))
439 rpc_set_tk_callback(task
, action
);
441 WARN_ON_ONCE(task
->tk_timeout
!= 0);
443 * Protect the queue operations.
446 __rpc_sleep_on_priority(q
, task
, task
->tk_priority
);
447 spin_unlock(&q
->lock
);
449 EXPORT_SYMBOL_GPL(rpc_sleep_on
);
451 void rpc_sleep_on_priority_timeout(struct rpc_wait_queue
*q
,
452 struct rpc_task
*task
, unsigned long timeout
, int priority
)
454 if (!rpc_sleep_check_activated(task
))
457 priority
-= RPC_PRIORITY_LOW
;
459 * Protect the queue operations.
462 __rpc_sleep_on_priority_timeout(q
, task
, timeout
, priority
);
463 spin_unlock(&q
->lock
);
465 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority_timeout
);
467 void rpc_sleep_on_priority(struct rpc_wait_queue
*q
, struct rpc_task
*task
,
470 if (!rpc_sleep_check_activated(task
))
473 WARN_ON_ONCE(task
->tk_timeout
!= 0);
474 priority
-= RPC_PRIORITY_LOW
;
476 * Protect the queue operations.
479 __rpc_sleep_on_priority(q
, task
, priority
);
480 spin_unlock(&q
->lock
);
482 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority
);
485 * __rpc_do_wake_up_task_on_wq - wake up a single rpc_task
486 * @wq: workqueue on which to run task
488 * @task: task to be woken up
490 * Caller must hold queue->lock, and have cleared the task queued flag.
492 static void __rpc_do_wake_up_task_on_wq(struct workqueue_struct
*wq
,
493 struct rpc_wait_queue
*queue
,
494 struct rpc_task
*task
)
496 /* Has the task been executed yet? If not, we cannot wake it up! */
497 if (!RPC_IS_ACTIVATED(task
)) {
498 printk(KERN_ERR
"RPC: Inactive task (%p) being woken up!\n", task
);
502 trace_rpc_task_wakeup(task
, queue
);
504 __rpc_remove_wait_queue(queue
, task
);
506 rpc_make_runnable(wq
, task
);
510 * Wake up a queued task while the queue lock is being held
512 static struct rpc_task
*
513 rpc_wake_up_task_on_wq_queue_action_locked(struct workqueue_struct
*wq
,
514 struct rpc_wait_queue
*queue
, struct rpc_task
*task
,
515 bool (*action
)(struct rpc_task
*, void *), void *data
)
517 if (RPC_IS_QUEUED(task
)) {
519 if (task
->tk_waitqueue
== queue
) {
520 if (action
== NULL
|| action(task
, data
)) {
521 __rpc_do_wake_up_task_on_wq(wq
, queue
, task
);
530 * Wake up a queued task while the queue lock is being held
532 static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue
*queue
,
533 struct rpc_task
*task
)
535 rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue
, queue
,
540 * Wake up a task on a specific queue
542 void rpc_wake_up_queued_task(struct rpc_wait_queue
*queue
, struct rpc_task
*task
)
544 if (!RPC_IS_QUEUED(task
))
546 spin_lock(&queue
->lock
);
547 rpc_wake_up_task_queue_locked(queue
, task
);
548 spin_unlock(&queue
->lock
);
550 EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task
);
552 static bool rpc_task_action_set_status(struct rpc_task
*task
, void *status
)
554 task
->tk_status
= *(int *)status
;
559 rpc_wake_up_task_queue_set_status_locked(struct rpc_wait_queue
*queue
,
560 struct rpc_task
*task
, int status
)
562 rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue
, queue
,
563 task
, rpc_task_action_set_status
, &status
);
567 * rpc_wake_up_queued_task_set_status - wake up a task and set task->tk_status
568 * @queue: pointer to rpc_wait_queue
569 * @task: pointer to rpc_task
570 * @status: integer error value
572 * If @task is queued on @queue, then it is woken up, and @task->tk_status is
573 * set to the value of @status.
576 rpc_wake_up_queued_task_set_status(struct rpc_wait_queue
*queue
,
577 struct rpc_task
*task
, int status
)
579 if (!RPC_IS_QUEUED(task
))
581 spin_lock(&queue
->lock
);
582 rpc_wake_up_task_queue_set_status_locked(queue
, task
, status
);
583 spin_unlock(&queue
->lock
);
587 * Wake up the next task on a priority queue.
589 static struct rpc_task
*__rpc_find_next_queued_priority(struct rpc_wait_queue
*queue
)
592 struct rpc_task
*task
;
595 * Service a batch of tasks from a single owner.
597 q
= &queue
->tasks
[queue
->priority
];
598 if (!list_empty(q
) && --queue
->nr
) {
599 task
= list_first_entry(q
, struct rpc_task
, u
.tk_wait
.list
);
604 * Service the next queue.
607 if (q
== &queue
->tasks
[0])
608 q
= &queue
->tasks
[queue
->maxpriority
];
611 if (!list_empty(q
)) {
612 task
= list_first_entry(q
, struct rpc_task
, u
.tk_wait
.list
);
615 } while (q
!= &queue
->tasks
[queue
->priority
]);
617 rpc_reset_waitqueue_priority(queue
);
621 rpc_set_waitqueue_priority(queue
, (unsigned int)(q
- &queue
->tasks
[0]));
626 static struct rpc_task
*__rpc_find_next_queued(struct rpc_wait_queue
*queue
)
628 if (RPC_IS_PRIORITY(queue
))
629 return __rpc_find_next_queued_priority(queue
);
630 if (!list_empty(&queue
->tasks
[0]))
631 return list_first_entry(&queue
->tasks
[0], struct rpc_task
, u
.tk_wait
.list
);
636 * Wake up the first task on the wait queue.
638 struct rpc_task
*rpc_wake_up_first_on_wq(struct workqueue_struct
*wq
,
639 struct rpc_wait_queue
*queue
,
640 bool (*func
)(struct rpc_task
*, void *), void *data
)
642 struct rpc_task
*task
= NULL
;
644 spin_lock(&queue
->lock
);
645 task
= __rpc_find_next_queued(queue
);
647 task
= rpc_wake_up_task_on_wq_queue_action_locked(wq
, queue
,
649 spin_unlock(&queue
->lock
);
655 * Wake up the first task on the wait queue.
657 struct rpc_task
*rpc_wake_up_first(struct rpc_wait_queue
*queue
,
658 bool (*func
)(struct rpc_task
*, void *), void *data
)
660 return rpc_wake_up_first_on_wq(rpciod_workqueue
, queue
, func
, data
);
662 EXPORT_SYMBOL_GPL(rpc_wake_up_first
);
664 static bool rpc_wake_up_next_func(struct rpc_task
*task
, void *data
)
670 * Wake up the next task on the wait queue.
672 struct rpc_task
*rpc_wake_up_next(struct rpc_wait_queue
*queue
)
674 return rpc_wake_up_first(queue
, rpc_wake_up_next_func
, NULL
);
676 EXPORT_SYMBOL_GPL(rpc_wake_up_next
);
679 * rpc_wake_up - wake up all rpc_tasks
680 * @queue: rpc_wait_queue on which the tasks are sleeping
684 void rpc_wake_up(struct rpc_wait_queue
*queue
)
686 struct list_head
*head
;
688 spin_lock(&queue
->lock
);
689 head
= &queue
->tasks
[queue
->maxpriority
];
691 while (!list_empty(head
)) {
692 struct rpc_task
*task
;
693 task
= list_first_entry(head
,
696 rpc_wake_up_task_queue_locked(queue
, task
);
698 if (head
== &queue
->tasks
[0])
702 spin_unlock(&queue
->lock
);
704 EXPORT_SYMBOL_GPL(rpc_wake_up
);
707 * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
708 * @queue: rpc_wait_queue on which the tasks are sleeping
709 * @status: status value to set
713 void rpc_wake_up_status(struct rpc_wait_queue
*queue
, int status
)
715 struct list_head
*head
;
717 spin_lock(&queue
->lock
);
718 head
= &queue
->tasks
[queue
->maxpriority
];
720 while (!list_empty(head
)) {
721 struct rpc_task
*task
;
722 task
= list_first_entry(head
,
725 task
->tk_status
= status
;
726 rpc_wake_up_task_queue_locked(queue
, task
);
728 if (head
== &queue
->tasks
[0])
732 spin_unlock(&queue
->lock
);
734 EXPORT_SYMBOL_GPL(rpc_wake_up_status
);
736 static void __rpc_queue_timer_fn(struct work_struct
*work
)
738 struct rpc_wait_queue
*queue
= container_of(work
,
739 struct rpc_wait_queue
,
740 timer_list
.dwork
.work
);
741 struct rpc_task
*task
, *n
;
742 unsigned long expires
, now
, timeo
;
744 spin_lock(&queue
->lock
);
745 expires
= now
= jiffies
;
746 list_for_each_entry_safe(task
, n
, &queue
->timer_list
.list
, u
.tk_wait
.timer_list
) {
747 timeo
= task
->tk_timeout
;
748 if (time_after_eq(now
, timeo
)) {
749 trace_rpc_task_timeout(task
, task
->tk_action
);
750 task
->tk_status
= -ETIMEDOUT
;
751 rpc_wake_up_task_queue_locked(queue
, task
);
754 if (expires
== now
|| time_after(expires
, timeo
))
757 if (!list_empty(&queue
->timer_list
.list
))
758 rpc_set_queue_timer(queue
, expires
);
759 spin_unlock(&queue
->lock
);
762 static void __rpc_atrun(struct rpc_task
*task
)
764 if (task
->tk_status
== -ETIMEDOUT
)
769 * Run a task at a later time
771 void rpc_delay(struct rpc_task
*task
, unsigned long delay
)
773 rpc_sleep_on_timeout(&delay_queue
, task
, __rpc_atrun
, jiffies
+ delay
);
775 EXPORT_SYMBOL_GPL(rpc_delay
);
778 * Helper to call task->tk_ops->rpc_call_prepare
780 void rpc_prepare_task(struct rpc_task
*task
)
782 task
->tk_ops
->rpc_call_prepare(task
, task
->tk_calldata
);
786 rpc_init_task_statistics(struct rpc_task
*task
)
788 /* Initialize retry counters */
789 task
->tk_garb_retry
= 2;
790 task
->tk_cred_retry
= 2;
791 task
->tk_rebind_retry
= 2;
793 /* starting timestamp */
794 task
->tk_start
= ktime_get();
798 rpc_reset_task_statistics(struct rpc_task
*task
)
800 task
->tk_timeouts
= 0;
801 task
->tk_flags
&= ~(RPC_CALL_MAJORSEEN
|RPC_TASK_SENT
);
802 rpc_init_task_statistics(task
);
806 * Helper that calls task->tk_ops->rpc_call_done if it exists
808 void rpc_exit_task(struct rpc_task
*task
)
810 trace_rpc_task_end(task
, task
->tk_action
);
811 task
->tk_action
= NULL
;
812 if (task
->tk_ops
->rpc_count_stats
)
813 task
->tk_ops
->rpc_count_stats(task
, task
->tk_calldata
);
814 else if (task
->tk_client
)
815 rpc_count_iostats(task
, task
->tk_client
->cl_metrics
);
816 if (task
->tk_ops
->rpc_call_done
!= NULL
) {
817 task
->tk_ops
->rpc_call_done(task
, task
->tk_calldata
);
818 if (task
->tk_action
!= NULL
) {
819 /* Always release the RPC slot and buffer memory */
821 rpc_reset_task_statistics(task
);
826 void rpc_signal_task(struct rpc_task
*task
)
828 struct rpc_wait_queue
*queue
;
830 if (!RPC_IS_ACTIVATED(task
))
833 trace_rpc_task_signalled(task
, task
->tk_action
);
834 set_bit(RPC_TASK_SIGNALLED
, &task
->tk_runstate
);
835 smp_mb__after_atomic();
836 queue
= READ_ONCE(task
->tk_waitqueue
);
838 rpc_wake_up_queued_task_set_status(queue
, task
, -ERESTARTSYS
);
841 void rpc_exit(struct rpc_task
*task
, int status
)
843 task
->tk_status
= status
;
844 task
->tk_action
= rpc_exit_task
;
845 rpc_wake_up_queued_task(task
->tk_waitqueue
, task
);
847 EXPORT_SYMBOL_GPL(rpc_exit
);
849 void rpc_release_calldata(const struct rpc_call_ops
*ops
, void *calldata
)
851 if (ops
->rpc_release
!= NULL
)
852 ops
->rpc_release(calldata
);
856 * This is the RPC `scheduler' (or rather, the finite state machine).
858 static void __rpc_execute(struct rpc_task
*task
)
860 struct rpc_wait_queue
*queue
;
861 int task_is_async
= RPC_IS_ASYNC(task
);
864 WARN_ON_ONCE(RPC_IS_QUEUED(task
));
865 if (RPC_IS_QUEUED(task
))
869 void (*do_action
)(struct rpc_task
*);
872 * Perform the next FSM step or a pending callback.
874 * tk_action may be NULL if the task has been killed.
875 * In particular, note that rpc_killall_tasks may
876 * do this at any time, so beware when dereferencing.
878 do_action
= task
->tk_action
;
879 if (task
->tk_callback
) {
880 do_action
= task
->tk_callback
;
881 task
->tk_callback
= NULL
;
885 trace_rpc_task_run_action(task
, do_action
);
889 * Lockless check for whether task is sleeping or not.
891 if (!RPC_IS_QUEUED(task
))
895 * Signalled tasks should exit rather than sleep.
897 if (RPC_SIGNALLED(task
)) {
898 task
->tk_rpc_status
= -ERESTARTSYS
;
899 rpc_exit(task
, -ERESTARTSYS
);
903 * The queue->lock protects against races with
904 * rpc_make_runnable().
906 * Note that once we clear RPC_TASK_RUNNING on an asynchronous
907 * rpc_task, rpc_make_runnable() can assign it to a
908 * different workqueue. We therefore cannot assume that the
909 * rpc_task pointer may still be dereferenced.
911 queue
= task
->tk_waitqueue
;
912 spin_lock(&queue
->lock
);
913 if (!RPC_IS_QUEUED(task
)) {
914 spin_unlock(&queue
->lock
);
917 rpc_clear_running(task
);
918 spin_unlock(&queue
->lock
);
922 /* sync task: sleep here */
923 trace_rpc_task_sync_sleep(task
, task
->tk_action
);
924 status
= out_of_line_wait_on_bit(&task
->tk_runstate
,
925 RPC_TASK_QUEUED
, rpc_wait_bit_killable
,
929 * When a sync task receives a signal, it exits with
930 * -ERESTARTSYS. In order to catch any callbacks that
931 * clean up after sleeping on some queue, we don't
932 * break the loop here, but go around once more.
934 trace_rpc_task_signalled(task
, task
->tk_action
);
935 set_bit(RPC_TASK_SIGNALLED
, &task
->tk_runstate
);
936 task
->tk_rpc_status
= -ERESTARTSYS
;
937 rpc_exit(task
, -ERESTARTSYS
);
939 trace_rpc_task_sync_wake(task
, task
->tk_action
);
942 /* Release all resources associated with the task */
943 rpc_release_task(task
);
947 * User-visible entry point to the scheduler.
949 * This may be called recursively if e.g. an async NFS task updates
950 * the attributes and finds that dirty pages must be flushed.
951 * NOTE: Upon exit of this function the task is guaranteed to be
952 * released. In particular note that tk_release() will have
953 * been called, so your task memory may have been freed.
955 void rpc_execute(struct rpc_task
*task
)
957 bool is_async
= RPC_IS_ASYNC(task
);
959 rpc_set_active(task
);
960 rpc_make_runnable(rpciod_workqueue
, task
);
965 static void rpc_async_schedule(struct work_struct
*work
)
967 unsigned int pflags
= memalloc_nofs_save();
969 __rpc_execute(container_of(work
, struct rpc_task
, u
.tk_work
));
970 memalloc_nofs_restore(pflags
);
974 * rpc_malloc - allocate RPC buffer resources
977 * A single memory region is allocated, which is split between the
978 * RPC call and RPC reply that this task is being used for. When
979 * this RPC is retired, the memory is released by calling rpc_free.
981 * To prevent rpciod from hanging, this allocator never sleeps,
982 * returning -ENOMEM and suppressing warning if the request cannot
983 * be serviced immediately. The caller can arrange to sleep in a
984 * way that is safe for rpciod.
986 * Most requests are 'small' (under 2KiB) and can be serviced from a
987 * mempool, ensuring that NFS reads and writes can always proceed,
988 * and that there is good locality of reference for these buffers.
990 int rpc_malloc(struct rpc_task
*task
)
992 struct rpc_rqst
*rqst
= task
->tk_rqstp
;
993 size_t size
= rqst
->rq_callsize
+ rqst
->rq_rcvsize
;
994 struct rpc_buffer
*buf
;
995 gfp_t gfp
= GFP_NOFS
;
997 if (RPC_IS_SWAPPER(task
))
998 gfp
= __GFP_MEMALLOC
| GFP_NOWAIT
| __GFP_NOWARN
;
1000 size
+= sizeof(struct rpc_buffer
);
1001 if (size
<= RPC_BUFFER_MAXSIZE
)
1002 buf
= mempool_alloc(rpc_buffer_mempool
, gfp
);
1004 buf
= kmalloc(size
, gfp
);
1010 rqst
->rq_buffer
= buf
->data
;
1011 rqst
->rq_rbuffer
= (char *)rqst
->rq_buffer
+ rqst
->rq_callsize
;
1014 EXPORT_SYMBOL_GPL(rpc_malloc
);
1017 * rpc_free - free RPC buffer resources allocated via rpc_malloc
1021 void rpc_free(struct rpc_task
*task
)
1023 void *buffer
= task
->tk_rqstp
->rq_buffer
;
1025 struct rpc_buffer
*buf
;
1027 buf
= container_of(buffer
, struct rpc_buffer
, data
);
1030 if (size
<= RPC_BUFFER_MAXSIZE
)
1031 mempool_free(buf
, rpc_buffer_mempool
);
1035 EXPORT_SYMBOL_GPL(rpc_free
);
1038 * Creation and deletion of RPC task structures
1040 static void rpc_init_task(struct rpc_task
*task
, const struct rpc_task_setup
*task_setup_data
)
1042 memset(task
, 0, sizeof(*task
));
1043 atomic_set(&task
->tk_count
, 1);
1044 task
->tk_flags
= task_setup_data
->flags
;
1045 task
->tk_ops
= task_setup_data
->callback_ops
;
1046 task
->tk_calldata
= task_setup_data
->callback_data
;
1047 INIT_LIST_HEAD(&task
->tk_task
);
1049 task
->tk_priority
= task_setup_data
->priority
- RPC_PRIORITY_LOW
;
1050 task
->tk_owner
= current
->tgid
;
1052 /* Initialize workqueue for async tasks */
1053 task
->tk_workqueue
= task_setup_data
->workqueue
;
1055 task
->tk_xprt
= rpc_task_get_xprt(task_setup_data
->rpc_client
,
1056 xprt_get(task_setup_data
->rpc_xprt
));
1058 task
->tk_op_cred
= get_rpccred(task_setup_data
->rpc_op_cred
);
1060 if (task
->tk_ops
->rpc_call_prepare
!= NULL
)
1061 task
->tk_action
= rpc_prepare_task
;
1063 rpc_init_task_statistics(task
);
1066 static struct rpc_task
*
1067 rpc_alloc_task(void)
1069 return (struct rpc_task
*)mempool_alloc(rpc_task_mempool
, GFP_NOFS
);
1073 * Create a new task for the specified client.
1075 struct rpc_task
*rpc_new_task(const struct rpc_task_setup
*setup_data
)
1077 struct rpc_task
*task
= setup_data
->task
;
1078 unsigned short flags
= 0;
1081 task
= rpc_alloc_task();
1082 flags
= RPC_TASK_DYNAMIC
;
1085 rpc_init_task(task
, setup_data
);
1086 task
->tk_flags
|= flags
;
1091 * rpc_free_task - release rpc task and perform cleanups
1093 * Note that we free up the rpc_task _after_ rpc_release_calldata()
1094 * in order to work around a workqueue dependency issue.
1097 * "Workqueue currently considers two work items to be the same if they're
1098 * on the same address and won't execute them concurrently - ie. it
1099 * makes a work item which is queued again while being executed wait
1100 * for the previous execution to complete.
1102 * If a work function frees the work item, and then waits for an event
1103 * which should be performed by another work item and *that* work item
1104 * recycles the freed work item, it can create a false dependency loop.
1105 * There really is no reliable way to detect this short of verifying
1106 * every memory free."
1109 static void rpc_free_task(struct rpc_task
*task
)
1111 unsigned short tk_flags
= task
->tk_flags
;
1113 put_rpccred(task
->tk_op_cred
);
1114 rpc_release_calldata(task
->tk_ops
, task
->tk_calldata
);
1116 if (tk_flags
& RPC_TASK_DYNAMIC
)
1117 mempool_free(task
, rpc_task_mempool
);
1120 static void rpc_async_release(struct work_struct
*work
)
1122 unsigned int pflags
= memalloc_nofs_save();
1124 rpc_free_task(container_of(work
, struct rpc_task
, u
.tk_work
));
1125 memalloc_nofs_restore(pflags
);
1128 static void rpc_release_resources_task(struct rpc_task
*task
)
1131 if (task
->tk_msg
.rpc_cred
) {
1132 if (!(task
->tk_flags
& RPC_TASK_CRED_NOREF
))
1133 put_cred(task
->tk_msg
.rpc_cred
);
1134 task
->tk_msg
.rpc_cred
= NULL
;
1136 rpc_task_release_client(task
);
1139 static void rpc_final_put_task(struct rpc_task
*task
,
1140 struct workqueue_struct
*q
)
1143 INIT_WORK(&task
->u
.tk_work
, rpc_async_release
);
1144 queue_work(q
, &task
->u
.tk_work
);
1146 rpc_free_task(task
);
1149 static void rpc_do_put_task(struct rpc_task
*task
, struct workqueue_struct
*q
)
1151 if (atomic_dec_and_test(&task
->tk_count
)) {
1152 rpc_release_resources_task(task
);
1153 rpc_final_put_task(task
, q
);
1157 void rpc_put_task(struct rpc_task
*task
)
1159 rpc_do_put_task(task
, NULL
);
1161 EXPORT_SYMBOL_GPL(rpc_put_task
);
1163 void rpc_put_task_async(struct rpc_task
*task
)
1165 rpc_do_put_task(task
, task
->tk_workqueue
);
1167 EXPORT_SYMBOL_GPL(rpc_put_task_async
);
1169 static void rpc_release_task(struct rpc_task
*task
)
1171 WARN_ON_ONCE(RPC_IS_QUEUED(task
));
1173 rpc_release_resources_task(task
);
1176 * Note: at this point we have been removed from rpc_clnt->cl_tasks,
1177 * so it should be safe to use task->tk_count as a test for whether
1178 * or not any other processes still hold references to our rpc_task.
1180 if (atomic_read(&task
->tk_count
) != 1 + !RPC_IS_ASYNC(task
)) {
1181 /* Wake up anyone who may be waiting for task completion */
1182 if (!rpc_complete_task(task
))
1185 if (!atomic_dec_and_test(&task
->tk_count
))
1188 rpc_final_put_task(task
, task
->tk_workqueue
);
1193 return try_module_get(THIS_MODULE
) ? 0 : -EINVAL
;
1196 void rpciod_down(void)
1198 module_put(THIS_MODULE
);
1202 * Start up the rpciod workqueue.
1204 static int rpciod_start(void)
1206 struct workqueue_struct
*wq
;
1209 * Create the rpciod thread and wait for it to start.
1211 wq
= alloc_workqueue("rpciod", WQ_MEM_RECLAIM
| WQ_UNBOUND
, 0);
1214 rpciod_workqueue
= wq
;
1215 /* Note: highpri because network receive is latency sensitive */
1216 wq
= alloc_workqueue("xprtiod", WQ_UNBOUND
|WQ_MEM_RECLAIM
|WQ_HIGHPRI
, 0);
1219 xprtiod_workqueue
= wq
;
1222 wq
= rpciod_workqueue
;
1223 rpciod_workqueue
= NULL
;
1224 destroy_workqueue(wq
);
1229 static void rpciod_stop(void)
1231 struct workqueue_struct
*wq
= NULL
;
1233 if (rpciod_workqueue
== NULL
)
1236 wq
= rpciod_workqueue
;
1237 rpciod_workqueue
= NULL
;
1238 destroy_workqueue(wq
);
1239 wq
= xprtiod_workqueue
;
1240 xprtiod_workqueue
= NULL
;
1241 destroy_workqueue(wq
);
1245 rpc_destroy_mempool(void)
1248 mempool_destroy(rpc_buffer_mempool
);
1249 mempool_destroy(rpc_task_mempool
);
1250 kmem_cache_destroy(rpc_task_slabp
);
1251 kmem_cache_destroy(rpc_buffer_slabp
);
1252 rpc_destroy_wait_queue(&delay_queue
);
1256 rpc_init_mempool(void)
1259 * The following is not strictly a mempool initialisation,
1260 * but there is no harm in doing it here
1262 rpc_init_wait_queue(&delay_queue
, "delayq");
1263 if (!rpciod_start())
1266 rpc_task_slabp
= kmem_cache_create("rpc_tasks",
1267 sizeof(struct rpc_task
),
1268 0, SLAB_HWCACHE_ALIGN
,
1270 if (!rpc_task_slabp
)
1272 rpc_buffer_slabp
= kmem_cache_create("rpc_buffers",
1274 0, SLAB_HWCACHE_ALIGN
,
1276 if (!rpc_buffer_slabp
)
1278 rpc_task_mempool
= mempool_create_slab_pool(RPC_TASK_POOLSIZE
,
1280 if (!rpc_task_mempool
)
1282 rpc_buffer_mempool
= mempool_create_slab_pool(RPC_BUFFER_POOLSIZE
,
1284 if (!rpc_buffer_mempool
)
1288 rpc_destroy_mempool();