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 INIT_LIST_HEAD(&task
->u
.tk_wait
.timer_list
);
208 if (RPC_IS_PRIORITY(queue
))
209 __rpc_add_wait_queue_priority(queue
, task
, queue_priority
);
210 else if (RPC_IS_SWAPPER(task
))
211 list_add(&task
->u
.tk_wait
.list
, &queue
->tasks
[0]);
213 list_add_tail(&task
->u
.tk_wait
.list
, &queue
->tasks
[0]);
214 task
->tk_waitqueue
= queue
;
216 /* barrier matches the read in rpc_wake_up_task_queue_locked() */
218 rpc_set_queued(task
);
220 dprintk("RPC: %5u added to queue %p \"%s\"\n",
221 task
->tk_pid
, queue
, rpc_qname(queue
));
225 * Remove request from a priority queue.
227 static void __rpc_remove_wait_queue_priority(struct rpc_task
*task
)
229 __rpc_list_dequeue_task(task
);
233 * Remove request from queue.
234 * Note: must be called with spin lock held.
236 static void __rpc_remove_wait_queue(struct rpc_wait_queue
*queue
, struct rpc_task
*task
)
238 __rpc_disable_timer(queue
, task
);
239 if (RPC_IS_PRIORITY(queue
))
240 __rpc_remove_wait_queue_priority(task
);
242 list_del(&task
->u
.tk_wait
.list
);
244 dprintk("RPC: %5u removed from queue %p \"%s\"\n",
245 task
->tk_pid
, queue
, rpc_qname(queue
));
248 static void __rpc_init_priority_wait_queue(struct rpc_wait_queue
*queue
, const char *qname
, unsigned char nr_queues
)
252 spin_lock_init(&queue
->lock
);
253 for (i
= 0; i
< ARRAY_SIZE(queue
->tasks
); i
++)
254 INIT_LIST_HEAD(&queue
->tasks
[i
]);
255 queue
->maxpriority
= nr_queues
- 1;
256 rpc_reset_waitqueue_priority(queue
);
258 queue
->timer_list
.expires
= 0;
259 INIT_DELAYED_WORK(&queue
->timer_list
.dwork
, __rpc_queue_timer_fn
);
260 INIT_LIST_HEAD(&queue
->timer_list
.list
);
261 rpc_assign_waitqueue_name(queue
, qname
);
264 void rpc_init_priority_wait_queue(struct rpc_wait_queue
*queue
, const char *qname
)
266 __rpc_init_priority_wait_queue(queue
, qname
, RPC_NR_PRIORITY
);
268 EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue
);
270 void rpc_init_wait_queue(struct rpc_wait_queue
*queue
, const char *qname
)
272 __rpc_init_priority_wait_queue(queue
, qname
, 1);
274 EXPORT_SYMBOL_GPL(rpc_init_wait_queue
);
276 void rpc_destroy_wait_queue(struct rpc_wait_queue
*queue
)
278 cancel_delayed_work_sync(&queue
->timer_list
.dwork
);
280 EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue
);
282 static int rpc_wait_bit_killable(struct wait_bit_key
*key
, int mode
)
284 freezable_schedule_unsafe();
285 if (signal_pending_state(mode
, current
))
290 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS)
291 static void rpc_task_set_debuginfo(struct rpc_task
*task
)
293 static atomic_t rpc_pid
;
295 task
->tk_pid
= atomic_inc_return(&rpc_pid
);
298 static inline void rpc_task_set_debuginfo(struct rpc_task
*task
)
303 static void rpc_set_active(struct rpc_task
*task
)
305 rpc_task_set_debuginfo(task
);
306 set_bit(RPC_TASK_ACTIVE
, &task
->tk_runstate
);
307 trace_rpc_task_begin(task
, NULL
);
311 * Mark an RPC call as having completed by clearing the 'active' bit
312 * and then waking up all tasks that were sleeping.
314 static int rpc_complete_task(struct rpc_task
*task
)
316 void *m
= &task
->tk_runstate
;
317 wait_queue_head_t
*wq
= bit_waitqueue(m
, RPC_TASK_ACTIVE
);
318 struct wait_bit_key k
= __WAIT_BIT_KEY_INITIALIZER(m
, RPC_TASK_ACTIVE
);
322 trace_rpc_task_complete(task
, NULL
);
324 spin_lock_irqsave(&wq
->lock
, flags
);
325 clear_bit(RPC_TASK_ACTIVE
, &task
->tk_runstate
);
326 ret
= atomic_dec_and_test(&task
->tk_count
);
327 if (waitqueue_active(wq
))
328 __wake_up_locked_key(wq
, TASK_NORMAL
, &k
);
329 spin_unlock_irqrestore(&wq
->lock
, flags
);
334 * Allow callers to wait for completion of an RPC call
336 * Note the use of out_of_line_wait_on_bit() rather than wait_on_bit()
337 * to enforce taking of the wq->lock and hence avoid races with
338 * rpc_complete_task().
340 int __rpc_wait_for_completion_task(struct rpc_task
*task
, wait_bit_action_f
*action
)
343 action
= rpc_wait_bit_killable
;
344 return out_of_line_wait_on_bit(&task
->tk_runstate
, RPC_TASK_ACTIVE
,
345 action
, TASK_KILLABLE
);
347 EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task
);
350 * Make an RPC task runnable.
352 * Note: If the task is ASYNC, and is being made runnable after sitting on an
353 * rpc_wait_queue, this must be called with the queue spinlock held to protect
354 * the wait queue operation.
355 * Note the ordering of rpc_test_and_set_running() and rpc_clear_queued(),
356 * which is needed to ensure that __rpc_execute() doesn't loop (due to the
357 * lockless RPC_IS_QUEUED() test) before we've had a chance to test
358 * the RPC_TASK_RUNNING flag.
360 static void rpc_make_runnable(struct workqueue_struct
*wq
,
361 struct rpc_task
*task
)
363 bool need_wakeup
= !rpc_test_and_set_running(task
);
365 rpc_clear_queued(task
);
368 if (RPC_IS_ASYNC(task
)) {
369 INIT_WORK(&task
->u
.tk_work
, rpc_async_schedule
);
370 queue_work(wq
, &task
->u
.tk_work
);
372 wake_up_bit(&task
->tk_runstate
, RPC_TASK_QUEUED
);
376 * Prepare for sleeping on a wait queue.
377 * By always appending tasks to the list we ensure FIFO behavior.
378 * NB: An RPC task will only receive interrupt-driven events as long
379 * as it's on a wait queue.
381 static void __rpc_do_sleep_on_priority(struct rpc_wait_queue
*q
,
382 struct rpc_task
*task
,
383 unsigned char queue_priority
)
385 dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n",
386 task
->tk_pid
, rpc_qname(q
), jiffies
);
388 trace_rpc_task_sleep(task
, q
);
390 __rpc_add_wait_queue(q
, task
, queue_priority
);
394 static void __rpc_sleep_on_priority(struct rpc_wait_queue
*q
,
395 struct rpc_task
*task
,
396 unsigned char queue_priority
)
398 if (WARN_ON_ONCE(RPC_IS_QUEUED(task
)))
400 __rpc_do_sleep_on_priority(q
, task
, queue_priority
);
403 static void __rpc_sleep_on_priority_timeout(struct rpc_wait_queue
*q
,
404 struct rpc_task
*task
, unsigned long timeout
,
405 unsigned char queue_priority
)
407 if (WARN_ON_ONCE(RPC_IS_QUEUED(task
)))
409 if (time_is_after_jiffies(timeout
)) {
410 __rpc_do_sleep_on_priority(q
, task
, queue_priority
);
411 __rpc_add_timer(q
, task
, timeout
);
413 task
->tk_status
= -ETIMEDOUT
;
416 static void rpc_set_tk_callback(struct rpc_task
*task
, rpc_action action
)
418 if (action
&& !WARN_ON_ONCE(task
->tk_callback
!= NULL
))
419 task
->tk_callback
= action
;
422 static bool rpc_sleep_check_activated(struct rpc_task
*task
)
424 /* We shouldn't ever put an inactive task to sleep */
425 if (WARN_ON_ONCE(!RPC_IS_ACTIVATED(task
))) {
426 task
->tk_status
= -EIO
;
427 rpc_put_task_async(task
);
433 void rpc_sleep_on_timeout(struct rpc_wait_queue
*q
, struct rpc_task
*task
,
434 rpc_action action
, unsigned long timeout
)
436 if (!rpc_sleep_check_activated(task
))
439 rpc_set_tk_callback(task
, action
);
442 * Protect the queue operations.
445 __rpc_sleep_on_priority_timeout(q
, task
, timeout
, task
->tk_priority
);
446 spin_unlock(&q
->lock
);
448 EXPORT_SYMBOL_GPL(rpc_sleep_on_timeout
);
450 void rpc_sleep_on(struct rpc_wait_queue
*q
, struct rpc_task
*task
,
453 if (!rpc_sleep_check_activated(task
))
456 rpc_set_tk_callback(task
, action
);
458 WARN_ON_ONCE(task
->tk_timeout
!= 0);
460 * Protect the queue operations.
463 __rpc_sleep_on_priority(q
, task
, task
->tk_priority
);
464 spin_unlock(&q
->lock
);
466 EXPORT_SYMBOL_GPL(rpc_sleep_on
);
468 void rpc_sleep_on_priority_timeout(struct rpc_wait_queue
*q
,
469 struct rpc_task
*task
, unsigned long timeout
, int priority
)
471 if (!rpc_sleep_check_activated(task
))
474 priority
-= RPC_PRIORITY_LOW
;
476 * Protect the queue operations.
479 __rpc_sleep_on_priority_timeout(q
, task
, timeout
, priority
);
480 spin_unlock(&q
->lock
);
482 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority_timeout
);
484 void rpc_sleep_on_priority(struct rpc_wait_queue
*q
, struct rpc_task
*task
,
487 if (!rpc_sleep_check_activated(task
))
490 WARN_ON_ONCE(task
->tk_timeout
!= 0);
491 priority
-= RPC_PRIORITY_LOW
;
493 * Protect the queue operations.
496 __rpc_sleep_on_priority(q
, task
, priority
);
497 spin_unlock(&q
->lock
);
499 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority
);
502 * __rpc_do_wake_up_task_on_wq - wake up a single rpc_task
503 * @wq: workqueue on which to run task
505 * @task: task to be woken up
507 * Caller must hold queue->lock, and have cleared the task queued flag.
509 static void __rpc_do_wake_up_task_on_wq(struct workqueue_struct
*wq
,
510 struct rpc_wait_queue
*queue
,
511 struct rpc_task
*task
)
513 dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
514 task
->tk_pid
, jiffies
);
516 /* Has the task been executed yet? If not, we cannot wake it up! */
517 if (!RPC_IS_ACTIVATED(task
)) {
518 printk(KERN_ERR
"RPC: Inactive task (%p) being woken up!\n", task
);
522 trace_rpc_task_wakeup(task
, queue
);
524 __rpc_remove_wait_queue(queue
, task
);
526 rpc_make_runnable(wq
, task
);
528 dprintk("RPC: __rpc_wake_up_task done\n");
532 * Wake up a queued task while the queue lock is being held
534 static struct rpc_task
*
535 rpc_wake_up_task_on_wq_queue_action_locked(struct workqueue_struct
*wq
,
536 struct rpc_wait_queue
*queue
, struct rpc_task
*task
,
537 bool (*action
)(struct rpc_task
*, void *), void *data
)
539 if (RPC_IS_QUEUED(task
)) {
541 if (task
->tk_waitqueue
== queue
) {
542 if (action
== NULL
|| action(task
, data
)) {
543 __rpc_do_wake_up_task_on_wq(wq
, queue
, task
);
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
,
555 struct rpc_task
*task
)
557 rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue
, queue
,
562 * Wake up a task on a specific queue
564 void rpc_wake_up_queued_task(struct rpc_wait_queue
*queue
, struct rpc_task
*task
)
566 if (!RPC_IS_QUEUED(task
))
568 spin_lock(&queue
->lock
);
569 rpc_wake_up_task_queue_locked(queue
, task
);
570 spin_unlock(&queue
->lock
);
572 EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task
);
574 static bool rpc_task_action_set_status(struct rpc_task
*task
, void *status
)
576 task
->tk_status
= *(int *)status
;
581 rpc_wake_up_task_queue_set_status_locked(struct rpc_wait_queue
*queue
,
582 struct rpc_task
*task
, int status
)
584 rpc_wake_up_task_on_wq_queue_action_locked(rpciod_workqueue
, queue
,
585 task
, rpc_task_action_set_status
, &status
);
589 * rpc_wake_up_queued_task_set_status - wake up a task and set task->tk_status
590 * @queue: pointer to rpc_wait_queue
591 * @task: pointer to rpc_task
592 * @status: integer error value
594 * If @task is queued on @queue, then it is woken up, and @task->tk_status is
595 * set to the value of @status.
598 rpc_wake_up_queued_task_set_status(struct rpc_wait_queue
*queue
,
599 struct rpc_task
*task
, int status
)
601 if (!RPC_IS_QUEUED(task
))
603 spin_lock(&queue
->lock
);
604 rpc_wake_up_task_queue_set_status_locked(queue
, task
, status
);
605 spin_unlock(&queue
->lock
);
609 * Wake up the next task on a priority queue.
611 static struct rpc_task
*__rpc_find_next_queued_priority(struct rpc_wait_queue
*queue
)
614 struct rpc_task
*task
;
617 * Service a batch of tasks from a single owner.
619 q
= &queue
->tasks
[queue
->priority
];
620 if (!list_empty(q
) && --queue
->nr
) {
621 task
= list_first_entry(q
, struct rpc_task
, u
.tk_wait
.list
);
626 * Service the next queue.
629 if (q
== &queue
->tasks
[0])
630 q
= &queue
->tasks
[queue
->maxpriority
];
633 if (!list_empty(q
)) {
634 task
= list_first_entry(q
, struct rpc_task
, u
.tk_wait
.list
);
637 } while (q
!= &queue
->tasks
[queue
->priority
]);
639 rpc_reset_waitqueue_priority(queue
);
643 rpc_set_waitqueue_priority(queue
, (unsigned int)(q
- &queue
->tasks
[0]));
648 static struct rpc_task
*__rpc_find_next_queued(struct rpc_wait_queue
*queue
)
650 if (RPC_IS_PRIORITY(queue
))
651 return __rpc_find_next_queued_priority(queue
);
652 if (!list_empty(&queue
->tasks
[0]))
653 return list_first_entry(&queue
->tasks
[0], struct rpc_task
, u
.tk_wait
.list
);
658 * Wake up the first task on the wait queue.
660 struct rpc_task
*rpc_wake_up_first_on_wq(struct workqueue_struct
*wq
,
661 struct rpc_wait_queue
*queue
,
662 bool (*func
)(struct rpc_task
*, void *), void *data
)
664 struct rpc_task
*task
= NULL
;
666 dprintk("RPC: wake_up_first(%p \"%s\")\n",
667 queue
, rpc_qname(queue
));
668 spin_lock(&queue
->lock
);
669 task
= __rpc_find_next_queued(queue
);
671 task
= rpc_wake_up_task_on_wq_queue_action_locked(wq
, queue
,
673 spin_unlock(&queue
->lock
);
679 * Wake up the first task on the wait queue.
681 struct rpc_task
*rpc_wake_up_first(struct rpc_wait_queue
*queue
,
682 bool (*func
)(struct rpc_task
*, void *), void *data
)
684 return rpc_wake_up_first_on_wq(rpciod_workqueue
, queue
, func
, data
);
686 EXPORT_SYMBOL_GPL(rpc_wake_up_first
);
688 static bool rpc_wake_up_next_func(struct rpc_task
*task
, void *data
)
694 * Wake up the next task on the wait queue.
696 struct rpc_task
*rpc_wake_up_next(struct rpc_wait_queue
*queue
)
698 return rpc_wake_up_first(queue
, rpc_wake_up_next_func
, NULL
);
700 EXPORT_SYMBOL_GPL(rpc_wake_up_next
);
703 * rpc_wake_up_locked - wake up all rpc_tasks
704 * @queue: rpc_wait_queue on which the tasks are sleeping
707 static void rpc_wake_up_locked(struct rpc_wait_queue
*queue
)
709 struct rpc_task
*task
;
712 task
= __rpc_find_next_queued(queue
);
715 rpc_wake_up_task_queue_locked(queue
, task
);
720 * rpc_wake_up - wake up all rpc_tasks
721 * @queue: rpc_wait_queue on which the tasks are sleeping
725 void rpc_wake_up(struct rpc_wait_queue
*queue
)
727 spin_lock(&queue
->lock
);
728 rpc_wake_up_locked(queue
);
729 spin_unlock(&queue
->lock
);
731 EXPORT_SYMBOL_GPL(rpc_wake_up
);
734 * rpc_wake_up_status_locked - wake up all rpc_tasks and set their status value.
735 * @queue: rpc_wait_queue on which the tasks are sleeping
736 * @status: status value to set
738 static void rpc_wake_up_status_locked(struct rpc_wait_queue
*queue
, int status
)
740 struct rpc_task
*task
;
743 task
= __rpc_find_next_queued(queue
);
746 rpc_wake_up_task_queue_set_status_locked(queue
, task
, status
);
751 * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
752 * @queue: rpc_wait_queue on which the tasks are sleeping
753 * @status: status value to set
757 void rpc_wake_up_status(struct rpc_wait_queue
*queue
, int status
)
759 spin_lock(&queue
->lock
);
760 rpc_wake_up_status_locked(queue
, status
);
761 spin_unlock(&queue
->lock
);
763 EXPORT_SYMBOL_GPL(rpc_wake_up_status
);
765 static void __rpc_queue_timer_fn(struct work_struct
*work
)
767 struct rpc_wait_queue
*queue
= container_of(work
,
768 struct rpc_wait_queue
,
769 timer_list
.dwork
.work
);
770 struct rpc_task
*task
, *n
;
771 unsigned long expires
, now
, timeo
;
773 spin_lock(&queue
->lock
);
774 expires
= now
= jiffies
;
775 list_for_each_entry_safe(task
, n
, &queue
->timer_list
.list
, u
.tk_wait
.timer_list
) {
776 timeo
= task
->tk_timeout
;
777 if (time_after_eq(now
, timeo
)) {
778 dprintk("RPC: %5u timeout\n", task
->tk_pid
);
779 task
->tk_status
= -ETIMEDOUT
;
780 rpc_wake_up_task_queue_locked(queue
, task
);
783 if (expires
== now
|| time_after(expires
, timeo
))
786 if (!list_empty(&queue
->timer_list
.list
))
787 rpc_set_queue_timer(queue
, expires
);
788 spin_unlock(&queue
->lock
);
791 static void __rpc_atrun(struct rpc_task
*task
)
793 if (task
->tk_status
== -ETIMEDOUT
)
798 * Run a task at a later time
800 void rpc_delay(struct rpc_task
*task
, unsigned long delay
)
802 rpc_sleep_on_timeout(&delay_queue
, task
, __rpc_atrun
, jiffies
+ delay
);
804 EXPORT_SYMBOL_GPL(rpc_delay
);
807 * Helper to call task->tk_ops->rpc_call_prepare
809 void rpc_prepare_task(struct rpc_task
*task
)
811 task
->tk_ops
->rpc_call_prepare(task
, task
->tk_calldata
);
815 rpc_init_task_statistics(struct rpc_task
*task
)
817 /* Initialize retry counters */
818 task
->tk_garb_retry
= 2;
819 task
->tk_cred_retry
= 2;
820 task
->tk_rebind_retry
= 2;
822 /* starting timestamp */
823 task
->tk_start
= ktime_get();
827 rpc_reset_task_statistics(struct rpc_task
*task
)
829 task
->tk_timeouts
= 0;
830 task
->tk_flags
&= ~(RPC_CALL_MAJORSEEN
|RPC_TASK_SENT
);
831 rpc_init_task_statistics(task
);
835 * Helper that calls task->tk_ops->rpc_call_done if it exists
837 void rpc_exit_task(struct rpc_task
*task
)
839 trace_rpc_task_end(task
, task
->tk_action
);
840 task
->tk_action
= NULL
;
841 if (task
->tk_ops
->rpc_count_stats
)
842 task
->tk_ops
->rpc_count_stats(task
, task
->tk_calldata
);
843 else if (task
->tk_client
)
844 rpc_count_iostats(task
, task
->tk_client
->cl_metrics
);
845 if (task
->tk_ops
->rpc_call_done
!= NULL
) {
846 task
->tk_ops
->rpc_call_done(task
, task
->tk_calldata
);
847 if (task
->tk_action
!= NULL
) {
848 /* Always release the RPC slot and buffer memory */
850 rpc_reset_task_statistics(task
);
855 void rpc_signal_task(struct rpc_task
*task
)
857 struct rpc_wait_queue
*queue
;
859 if (!RPC_IS_ACTIVATED(task
))
861 set_bit(RPC_TASK_SIGNALLED
, &task
->tk_runstate
);
862 smp_mb__after_atomic();
863 queue
= READ_ONCE(task
->tk_waitqueue
);
865 rpc_wake_up_queued_task_set_status(queue
, task
, -ERESTARTSYS
);
868 void rpc_exit(struct rpc_task
*task
, int status
)
870 task
->tk_status
= status
;
871 task
->tk_action
= rpc_exit_task
;
872 rpc_wake_up_queued_task(task
->tk_waitqueue
, task
);
874 EXPORT_SYMBOL_GPL(rpc_exit
);
876 void rpc_release_calldata(const struct rpc_call_ops
*ops
, void *calldata
)
878 if (ops
->rpc_release
!= NULL
)
879 ops
->rpc_release(calldata
);
883 * This is the RPC `scheduler' (or rather, the finite state machine).
885 static void __rpc_execute(struct rpc_task
*task
)
887 struct rpc_wait_queue
*queue
;
888 int task_is_async
= RPC_IS_ASYNC(task
);
891 dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
892 task
->tk_pid
, task
->tk_flags
);
894 WARN_ON_ONCE(RPC_IS_QUEUED(task
));
895 if (RPC_IS_QUEUED(task
))
899 void (*do_action
)(struct rpc_task
*);
902 * Perform the next FSM step or a pending callback.
904 * tk_action may be NULL if the task has been killed.
905 * In particular, note that rpc_killall_tasks may
906 * do this at any time, so beware when dereferencing.
908 do_action
= task
->tk_action
;
909 if (task
->tk_callback
) {
910 do_action
= task
->tk_callback
;
911 task
->tk_callback
= NULL
;
915 trace_rpc_task_run_action(task
, do_action
);
919 * Lockless check for whether task is sleeping or not.
921 if (!RPC_IS_QUEUED(task
))
925 * Signalled tasks should exit rather than sleep.
927 if (RPC_SIGNALLED(task
)) {
928 task
->tk_rpc_status
= -ERESTARTSYS
;
929 rpc_exit(task
, -ERESTARTSYS
);
933 * The queue->lock protects against races with
934 * rpc_make_runnable().
936 * Note that once we clear RPC_TASK_RUNNING on an asynchronous
937 * rpc_task, rpc_make_runnable() can assign it to a
938 * different workqueue. We therefore cannot assume that the
939 * rpc_task pointer may still be dereferenced.
941 queue
= task
->tk_waitqueue
;
942 spin_lock(&queue
->lock
);
943 if (!RPC_IS_QUEUED(task
)) {
944 spin_unlock(&queue
->lock
);
947 rpc_clear_running(task
);
948 spin_unlock(&queue
->lock
);
952 /* sync task: sleep here */
953 dprintk("RPC: %5u sync task going to sleep\n", task
->tk_pid
);
954 status
= out_of_line_wait_on_bit(&task
->tk_runstate
,
955 RPC_TASK_QUEUED
, rpc_wait_bit_killable
,
959 * When a sync task receives a signal, it exits with
960 * -ERESTARTSYS. In order to catch any callbacks that
961 * clean up after sleeping on some queue, we don't
962 * break the loop here, but go around once more.
964 dprintk("RPC: %5u got signal\n", task
->tk_pid
);
965 set_bit(RPC_TASK_SIGNALLED
, &task
->tk_runstate
);
966 task
->tk_rpc_status
= -ERESTARTSYS
;
967 rpc_exit(task
, -ERESTARTSYS
);
969 dprintk("RPC: %5u sync task resuming\n", task
->tk_pid
);
972 dprintk("RPC: %5u return %d, status %d\n", task
->tk_pid
, status
,
974 /* Release all resources associated with the task */
975 rpc_release_task(task
);
979 * User-visible entry point to the scheduler.
981 * This may be called recursively if e.g. an async NFS task updates
982 * the attributes and finds that dirty pages must be flushed.
983 * NOTE: Upon exit of this function the task is guaranteed to be
984 * released. In particular note that tk_release() will have
985 * been called, so your task memory may have been freed.
987 void rpc_execute(struct rpc_task
*task
)
989 bool is_async
= RPC_IS_ASYNC(task
);
991 rpc_set_active(task
);
992 rpc_make_runnable(rpciod_workqueue
, task
);
994 unsigned int pflags
= memalloc_nofs_save();
996 memalloc_nofs_restore(pflags
);
1000 static void rpc_async_schedule(struct work_struct
*work
)
1002 unsigned int pflags
= memalloc_nofs_save();
1004 __rpc_execute(container_of(work
, struct rpc_task
, u
.tk_work
));
1005 memalloc_nofs_restore(pflags
);
1009 * rpc_malloc - allocate RPC buffer resources
1012 * A single memory region is allocated, which is split between the
1013 * RPC call and RPC reply that this task is being used for. When
1014 * this RPC is retired, the memory is released by calling rpc_free.
1016 * To prevent rpciod from hanging, this allocator never sleeps,
1017 * returning -ENOMEM and suppressing warning if the request cannot
1018 * be serviced immediately. The caller can arrange to sleep in a
1019 * way that is safe for rpciod.
1021 * Most requests are 'small' (under 2KiB) and can be serviced from a
1022 * mempool, ensuring that NFS reads and writes can always proceed,
1023 * and that there is good locality of reference for these buffers.
1025 int rpc_malloc(struct rpc_task
*task
)
1027 struct rpc_rqst
*rqst
= task
->tk_rqstp
;
1028 size_t size
= rqst
->rq_callsize
+ rqst
->rq_rcvsize
;
1029 struct rpc_buffer
*buf
;
1030 gfp_t gfp
= GFP_NOFS
;
1032 if (RPC_IS_SWAPPER(task
))
1033 gfp
= __GFP_MEMALLOC
| GFP_NOWAIT
| __GFP_NOWARN
;
1035 size
+= sizeof(struct rpc_buffer
);
1036 if (size
<= RPC_BUFFER_MAXSIZE
)
1037 buf
= mempool_alloc(rpc_buffer_mempool
, gfp
);
1039 buf
= kmalloc(size
, gfp
);
1045 dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
1046 task
->tk_pid
, size
, buf
);
1047 rqst
->rq_buffer
= buf
->data
;
1048 rqst
->rq_rbuffer
= (char *)rqst
->rq_buffer
+ rqst
->rq_callsize
;
1051 EXPORT_SYMBOL_GPL(rpc_malloc
);
1054 * rpc_free - free RPC buffer resources allocated via rpc_malloc
1058 void rpc_free(struct rpc_task
*task
)
1060 void *buffer
= task
->tk_rqstp
->rq_buffer
;
1062 struct rpc_buffer
*buf
;
1064 buf
= container_of(buffer
, struct rpc_buffer
, data
);
1067 dprintk("RPC: freeing buffer of size %zu at %p\n",
1070 if (size
<= RPC_BUFFER_MAXSIZE
)
1071 mempool_free(buf
, rpc_buffer_mempool
);
1075 EXPORT_SYMBOL_GPL(rpc_free
);
1078 * Creation and deletion of RPC task structures
1080 static void rpc_init_task(struct rpc_task
*task
, const struct rpc_task_setup
*task_setup_data
)
1082 memset(task
, 0, sizeof(*task
));
1083 atomic_set(&task
->tk_count
, 1);
1084 task
->tk_flags
= task_setup_data
->flags
;
1085 task
->tk_ops
= task_setup_data
->callback_ops
;
1086 task
->tk_calldata
= task_setup_data
->callback_data
;
1087 INIT_LIST_HEAD(&task
->tk_task
);
1089 task
->tk_priority
= task_setup_data
->priority
- RPC_PRIORITY_LOW
;
1090 task
->tk_owner
= current
->tgid
;
1092 /* Initialize workqueue for async tasks */
1093 task
->tk_workqueue
= task_setup_data
->workqueue
;
1095 task
->tk_xprt
= rpc_task_get_xprt(task_setup_data
->rpc_client
,
1096 xprt_get(task_setup_data
->rpc_xprt
));
1098 task
->tk_op_cred
= get_rpccred(task_setup_data
->rpc_op_cred
);
1100 if (task
->tk_ops
->rpc_call_prepare
!= NULL
)
1101 task
->tk_action
= rpc_prepare_task
;
1103 rpc_init_task_statistics(task
);
1105 dprintk("RPC: new task initialized, procpid %u\n",
1106 task_pid_nr(current
));
1109 static struct rpc_task
*
1110 rpc_alloc_task(void)
1112 return (struct rpc_task
*)mempool_alloc(rpc_task_mempool
, GFP_NOFS
);
1116 * Create a new task for the specified client.
1118 struct rpc_task
*rpc_new_task(const struct rpc_task_setup
*setup_data
)
1120 struct rpc_task
*task
= setup_data
->task
;
1121 unsigned short flags
= 0;
1124 task
= rpc_alloc_task();
1125 flags
= RPC_TASK_DYNAMIC
;
1128 rpc_init_task(task
, setup_data
);
1129 task
->tk_flags
|= flags
;
1130 dprintk("RPC: allocated task %p\n", task
);
1135 * rpc_free_task - release rpc task and perform cleanups
1137 * Note that we free up the rpc_task _after_ rpc_release_calldata()
1138 * in order to work around a workqueue dependency issue.
1141 * "Workqueue currently considers two work items to be the same if they're
1142 * on the same address and won't execute them concurrently - ie. it
1143 * makes a work item which is queued again while being executed wait
1144 * for the previous execution to complete.
1146 * If a work function frees the work item, and then waits for an event
1147 * which should be performed by another work item and *that* work item
1148 * recycles the freed work item, it can create a false dependency loop.
1149 * There really is no reliable way to detect this short of verifying
1150 * every memory free."
1153 static void rpc_free_task(struct rpc_task
*task
)
1155 unsigned short tk_flags
= task
->tk_flags
;
1157 put_rpccred(task
->tk_op_cred
);
1158 rpc_release_calldata(task
->tk_ops
, task
->tk_calldata
);
1160 if (tk_flags
& RPC_TASK_DYNAMIC
) {
1161 dprintk("RPC: %5u freeing task\n", task
->tk_pid
);
1162 mempool_free(task
, rpc_task_mempool
);
1166 static void rpc_async_release(struct work_struct
*work
)
1168 unsigned int pflags
= memalloc_nofs_save();
1170 rpc_free_task(container_of(work
, struct rpc_task
, u
.tk_work
));
1171 memalloc_nofs_restore(pflags
);
1174 static void rpc_release_resources_task(struct rpc_task
*task
)
1177 if (task
->tk_msg
.rpc_cred
) {
1178 put_cred(task
->tk_msg
.rpc_cred
);
1179 task
->tk_msg
.rpc_cred
= NULL
;
1181 rpc_task_release_client(task
);
1184 static void rpc_final_put_task(struct rpc_task
*task
,
1185 struct workqueue_struct
*q
)
1188 INIT_WORK(&task
->u
.tk_work
, rpc_async_release
);
1189 queue_work(q
, &task
->u
.tk_work
);
1191 rpc_free_task(task
);
1194 static void rpc_do_put_task(struct rpc_task
*task
, struct workqueue_struct
*q
)
1196 if (atomic_dec_and_test(&task
->tk_count
)) {
1197 rpc_release_resources_task(task
);
1198 rpc_final_put_task(task
, q
);
1202 void rpc_put_task(struct rpc_task
*task
)
1204 rpc_do_put_task(task
, NULL
);
1206 EXPORT_SYMBOL_GPL(rpc_put_task
);
1208 void rpc_put_task_async(struct rpc_task
*task
)
1210 rpc_do_put_task(task
, task
->tk_workqueue
);
1212 EXPORT_SYMBOL_GPL(rpc_put_task_async
);
1214 static void rpc_release_task(struct rpc_task
*task
)
1216 dprintk("RPC: %5u release task\n", task
->tk_pid
);
1218 WARN_ON_ONCE(RPC_IS_QUEUED(task
));
1220 rpc_release_resources_task(task
);
1223 * Note: at this point we have been removed from rpc_clnt->cl_tasks,
1224 * so it should be safe to use task->tk_count as a test for whether
1225 * or not any other processes still hold references to our rpc_task.
1227 if (atomic_read(&task
->tk_count
) != 1 + !RPC_IS_ASYNC(task
)) {
1228 /* Wake up anyone who may be waiting for task completion */
1229 if (!rpc_complete_task(task
))
1232 if (!atomic_dec_and_test(&task
->tk_count
))
1235 rpc_final_put_task(task
, task
->tk_workqueue
);
1240 return try_module_get(THIS_MODULE
) ? 0 : -EINVAL
;
1243 void rpciod_down(void)
1245 module_put(THIS_MODULE
);
1249 * Start up the rpciod workqueue.
1251 static int rpciod_start(void)
1253 struct workqueue_struct
*wq
;
1256 * Create the rpciod thread and wait for it to start.
1258 dprintk("RPC: creating workqueue rpciod\n");
1259 wq
= alloc_workqueue("rpciod", WQ_MEM_RECLAIM
| WQ_UNBOUND
, 0);
1262 rpciod_workqueue
= wq
;
1263 /* Note: highpri because network receive is latency sensitive */
1264 wq
= alloc_workqueue("xprtiod", WQ_UNBOUND
|WQ_MEM_RECLAIM
|WQ_HIGHPRI
, 0);
1267 xprtiod_workqueue
= wq
;
1270 wq
= rpciod_workqueue
;
1271 rpciod_workqueue
= NULL
;
1272 destroy_workqueue(wq
);
1277 static void rpciod_stop(void)
1279 struct workqueue_struct
*wq
= NULL
;
1281 if (rpciod_workqueue
== NULL
)
1283 dprintk("RPC: destroying workqueue rpciod\n");
1285 wq
= rpciod_workqueue
;
1286 rpciod_workqueue
= NULL
;
1287 destroy_workqueue(wq
);
1288 wq
= xprtiod_workqueue
;
1289 xprtiod_workqueue
= NULL
;
1290 destroy_workqueue(wq
);
1294 rpc_destroy_mempool(void)
1297 mempool_destroy(rpc_buffer_mempool
);
1298 mempool_destroy(rpc_task_mempool
);
1299 kmem_cache_destroy(rpc_task_slabp
);
1300 kmem_cache_destroy(rpc_buffer_slabp
);
1301 rpc_destroy_wait_queue(&delay_queue
);
1305 rpc_init_mempool(void)
1308 * The following is not strictly a mempool initialisation,
1309 * but there is no harm in doing it here
1311 rpc_init_wait_queue(&delay_queue
, "delayq");
1312 if (!rpciod_start())
1315 rpc_task_slabp
= kmem_cache_create("rpc_tasks",
1316 sizeof(struct rpc_task
),
1317 0, SLAB_HWCACHE_ALIGN
,
1319 if (!rpc_task_slabp
)
1321 rpc_buffer_slabp
= kmem_cache_create("rpc_buffers",
1323 0, SLAB_HWCACHE_ALIGN
,
1325 if (!rpc_buffer_slabp
)
1327 rpc_task_mempool
= mempool_create_slab_pool(RPC_TASK_POOLSIZE
,
1329 if (!rpc_task_mempool
)
1331 rpc_buffer_mempool
= mempool_create_slab_pool(RPC_BUFFER_POOLSIZE
,
1333 if (!rpc_buffer_mempool
)
1337 rpc_destroy_mempool();