2 * linux/net/sunrpc/sched.c
4 * Scheduling for synchronous and asynchronous RPC requests.
6 * Copyright (C) 1996 Olaf Kirch, <okir@monad.swb.de>
8 * TCP NFS related read + write fixes
9 * (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
12 #include <linux/module.h>
14 #include <linux/sched.h>
15 #include <linux/interrupt.h>
16 #include <linux/slab.h>
17 #include <linux/mempool.h>
18 #include <linux/smp.h>
19 #include <linux/spinlock.h>
20 #include <linux/mutex.h>
21 #include <linux/freezer.h>
23 #include <linux/sunrpc/clnt.h>
27 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
28 #define RPCDBG_FACILITY RPCDBG_SCHED
31 #define CREATE_TRACE_POINTS
32 #include <trace/events/sunrpc.h>
35 * RPC slabs and memory pools
37 #define RPC_BUFFER_MAXSIZE (2048)
38 #define RPC_BUFFER_POOLSIZE (8)
39 #define RPC_TASK_POOLSIZE (8)
40 static struct kmem_cache *rpc_task_slabp __read_mostly;
41 static struct kmem_cache *rpc_buffer_slabp __read_mostly;
42 static mempool_t *rpc_task_mempool __read_mostly;
43 static mempool_t *rpc_buffer_mempool __read_mostly;
45 static void rpc_async_schedule(struct work_struct *);
46 static void rpc_release_task(struct rpc_task *task);
47 static void __rpc_queue_timer_fn(unsigned long ptr);
50 * RPC tasks sit here while waiting for conditions to improve.
52 static struct rpc_wait_queue delay_queue;
55 * rpciod-related stuff
57 struct workqueue_struct *rpciod_workqueue;
60 * Disable the timer for a given RPC task. Should be called with
61 * queue->lock and bh_disabled in order to avoid races within
65 __rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
67 if (task->tk_timeout == 0)
69 dprintk("RPC: %5u disabling timer\n", task->tk_pid);
71 list_del(&task->u.tk_wait.timer_list);
72 if (list_empty(&queue->timer_list.list))
73 del_timer(&queue->timer_list.timer);
77 rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)
79 queue->timer_list.expires = expires;
80 mod_timer(&queue->timer_list.timer, expires);
84 * Set up a timer for the current task.
87 __rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
89 if (!task->tk_timeout)
92 dprintk("RPC: %5u setting alarm for %u ms\n",
93 task->tk_pid, jiffies_to_msecs(task->tk_timeout));
95 task->u.tk_wait.expires = jiffies + task->tk_timeout;
96 if (list_empty(&queue->timer_list.list) || time_before(task->u.tk_wait.expires, queue->timer_list.expires))
97 rpc_set_queue_timer(queue, task->u.tk_wait.expires);
98 list_add(&task->u.tk_wait.timer_list, &queue->timer_list.list);
101 static void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
103 if (queue->priority != priority) {
104 queue->priority = priority;
105 queue->nr = 1U << priority;
109 static void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
111 rpc_set_waitqueue_priority(queue, queue->maxpriority);
115 * Add a request to a queue list
118 __rpc_list_enqueue_task(struct list_head *q, struct rpc_task *task)
122 list_for_each_entry(t, q, u.tk_wait.list) {
123 if (t->tk_owner == task->tk_owner) {
124 list_add_tail(&task->u.tk_wait.links,
125 &t->u.tk_wait.links);
126 /* Cache the queue head in task->u.tk_wait.list */
127 task->u.tk_wait.list.next = q;
128 task->u.tk_wait.list.prev = NULL;
132 INIT_LIST_HEAD(&task->u.tk_wait.links);
133 list_add_tail(&task->u.tk_wait.list, q);
137 * Remove request from a queue list
140 __rpc_list_dequeue_task(struct rpc_task *task)
145 if (task->u.tk_wait.list.prev == NULL) {
146 list_del(&task->u.tk_wait.links);
149 if (!list_empty(&task->u.tk_wait.links)) {
150 t = list_first_entry(&task->u.tk_wait.links,
153 /* Assume __rpc_list_enqueue_task() cached the queue head */
154 q = t->u.tk_wait.list.next;
155 list_add_tail(&t->u.tk_wait.list, q);
156 list_del(&task->u.tk_wait.links);
158 list_del(&task->u.tk_wait.list);
162 * Add new request to a priority queue.
164 static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue,
165 struct rpc_task *task,
166 unsigned char queue_priority)
168 if (unlikely(queue_priority > queue->maxpriority))
169 queue_priority = queue->maxpriority;
170 __rpc_list_enqueue_task(&queue->tasks[queue_priority], task);
174 * Add new request to wait queue.
176 * Swapper tasks always get inserted at the head of the queue.
177 * This should avoid many nasty memory deadlocks and hopefully
178 * improve overall performance.
179 * Everyone else gets appended to the queue to ensure proper FIFO behavior.
181 static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
182 struct rpc_task *task,
183 unsigned char queue_priority)
185 WARN_ON_ONCE(RPC_IS_QUEUED(task));
186 if (RPC_IS_QUEUED(task))
189 if (RPC_IS_PRIORITY(queue))
190 __rpc_add_wait_queue_priority(queue, task, queue_priority);
191 else if (RPC_IS_SWAPPER(task))
192 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
194 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
195 task->tk_waitqueue = queue;
197 /* barrier matches the read in rpc_wake_up_task_queue_locked() */
199 rpc_set_queued(task);
201 dprintk("RPC: %5u added to queue %p \"%s\"\n",
202 task->tk_pid, queue, rpc_qname(queue));
206 * Remove request from a priority queue.
208 static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
210 __rpc_list_dequeue_task(task);
214 * Remove request from queue.
215 * Note: must be called with spin lock held.
217 static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
219 __rpc_disable_timer(queue, task);
220 if (RPC_IS_PRIORITY(queue))
221 __rpc_remove_wait_queue_priority(task);
223 list_del(&task->u.tk_wait.list);
225 dprintk("RPC: %5u removed from queue %p \"%s\"\n",
226 task->tk_pid, queue, rpc_qname(queue));
229 static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
233 spin_lock_init(&queue->lock);
234 for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
235 INIT_LIST_HEAD(&queue->tasks[i]);
236 queue->maxpriority = nr_queues - 1;
237 rpc_reset_waitqueue_priority(queue);
239 setup_timer(&queue->timer_list.timer, __rpc_queue_timer_fn, (unsigned long)queue);
240 INIT_LIST_HEAD(&queue->timer_list.list);
241 rpc_assign_waitqueue_name(queue, qname);
244 void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
246 __rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY);
248 EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue);
250 void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
252 __rpc_init_priority_wait_queue(queue, qname, 1);
254 EXPORT_SYMBOL_GPL(rpc_init_wait_queue);
256 void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)
258 del_timer_sync(&queue->timer_list.timer);
260 EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
262 static int rpc_wait_bit_killable(struct wait_bit_key *key, int mode)
264 freezable_schedule_unsafe();
265 if (signal_pending_state(mode, current))
270 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS)
271 static void rpc_task_set_debuginfo(struct rpc_task *task)
273 static atomic_t rpc_pid;
275 task->tk_pid = atomic_inc_return(&rpc_pid);
278 static inline void rpc_task_set_debuginfo(struct rpc_task *task)
283 static void rpc_set_active(struct rpc_task *task)
285 rpc_task_set_debuginfo(task);
286 set_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
287 trace_rpc_task_begin(task->tk_client, task, NULL);
291 * Mark an RPC call as having completed by clearing the 'active' bit
292 * and then waking up all tasks that were sleeping.
294 static int rpc_complete_task(struct rpc_task *task)
296 void *m = &task->tk_runstate;
297 wait_queue_head_t *wq = bit_waitqueue(m, RPC_TASK_ACTIVE);
298 struct wait_bit_key k = __WAIT_BIT_KEY_INITIALIZER(m, RPC_TASK_ACTIVE);
302 trace_rpc_task_complete(task->tk_client, task, NULL);
304 spin_lock_irqsave(&wq->lock, flags);
305 clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
306 ret = atomic_dec_and_test(&task->tk_count);
307 if (waitqueue_active(wq))
308 __wake_up_locked_key(wq, TASK_NORMAL, &k);
309 spin_unlock_irqrestore(&wq->lock, flags);
314 * Allow callers to wait for completion of an RPC call
316 * Note the use of out_of_line_wait_on_bit() rather than wait_on_bit()
317 * to enforce taking of the wq->lock and hence avoid races with
318 * rpc_complete_task().
320 int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *action)
323 action = rpc_wait_bit_killable;
324 return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
325 action, TASK_KILLABLE);
327 EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
330 * Make an RPC task runnable.
332 * Note: If the task is ASYNC, and is being made runnable after sitting on an
333 * rpc_wait_queue, this must be called with the queue spinlock held to protect
334 * the wait queue operation.
335 * Note the ordering of rpc_test_and_set_running() and rpc_clear_queued(),
336 * which is needed to ensure that __rpc_execute() doesn't loop (due to the
337 * lockless RPC_IS_QUEUED() test) before we've had a chance to test
338 * the RPC_TASK_RUNNING flag.
340 static void rpc_make_runnable(struct rpc_task *task)
342 bool need_wakeup = !rpc_test_and_set_running(task);
344 rpc_clear_queued(task);
347 if (RPC_IS_ASYNC(task)) {
348 INIT_WORK(&task->u.tk_work, rpc_async_schedule);
349 queue_work(rpciod_workqueue, &task->u.tk_work);
351 wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
355 * Prepare for sleeping on a wait queue.
356 * By always appending tasks to the list we ensure FIFO behavior.
357 * NB: An RPC task will only receive interrupt-driven events as long
358 * as it's on a wait queue.
360 static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
361 struct rpc_task *task,
363 unsigned char queue_priority)
365 dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n",
366 task->tk_pid, rpc_qname(q), jiffies);
368 trace_rpc_task_sleep(task->tk_client, task, q);
370 __rpc_add_wait_queue(q, task, queue_priority);
372 WARN_ON_ONCE(task->tk_callback != NULL);
373 task->tk_callback = action;
374 __rpc_add_timer(q, task);
377 void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
380 /* We shouldn't ever put an inactive task to sleep */
381 WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
382 if (!RPC_IS_ACTIVATED(task)) {
383 task->tk_status = -EIO;
384 rpc_put_task_async(task);
389 * Protect the queue operations.
391 spin_lock_bh(&q->lock);
392 __rpc_sleep_on_priority(q, task, action, task->tk_priority);
393 spin_unlock_bh(&q->lock);
395 EXPORT_SYMBOL_GPL(rpc_sleep_on);
397 void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
398 rpc_action action, int priority)
400 /* We shouldn't ever put an inactive task to sleep */
401 WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
402 if (!RPC_IS_ACTIVATED(task)) {
403 task->tk_status = -EIO;
404 rpc_put_task_async(task);
409 * Protect the queue operations.
411 spin_lock_bh(&q->lock);
412 __rpc_sleep_on_priority(q, task, action, priority - RPC_PRIORITY_LOW);
413 spin_unlock_bh(&q->lock);
415 EXPORT_SYMBOL_GPL(rpc_sleep_on_priority);
418 * __rpc_do_wake_up_task - wake up a single rpc_task
420 * @task: task to be woken up
422 * Caller must hold queue->lock, and have cleared the task queued flag.
424 static void __rpc_do_wake_up_task(struct rpc_wait_queue *queue, struct rpc_task *task)
426 dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
427 task->tk_pid, jiffies);
429 /* Has the task been executed yet? If not, we cannot wake it up! */
430 if (!RPC_IS_ACTIVATED(task)) {
431 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
435 trace_rpc_task_wakeup(task->tk_client, task, queue);
437 __rpc_remove_wait_queue(queue, task);
439 rpc_make_runnable(task);
441 dprintk("RPC: __rpc_wake_up_task done\n");
445 * Wake up a queued task while the queue lock is being held
447 static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
449 if (RPC_IS_QUEUED(task)) {
451 if (task->tk_waitqueue == queue)
452 __rpc_do_wake_up_task(queue, task);
457 * Wake up a task on a specific queue
459 void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
461 spin_lock_bh(&queue->lock);
462 rpc_wake_up_task_queue_locked(queue, task);
463 spin_unlock_bh(&queue->lock);
465 EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
468 * Wake up the next task on a priority queue.
470 static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *queue)
473 struct rpc_task *task;
476 * Service the privileged queue.
478 q = &queue->tasks[RPC_NR_PRIORITY - 1];
479 if (queue->maxpriority > RPC_PRIORITY_PRIVILEGED && !list_empty(q)) {
480 task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
485 * Service a batch of tasks from a single owner.
487 q = &queue->tasks[queue->priority];
488 if (!list_empty(q) && queue->nr) {
490 task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
495 * Service the next queue.
498 if (q == &queue->tasks[0])
499 q = &queue->tasks[queue->maxpriority];
502 if (!list_empty(q)) {
503 task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
506 } while (q != &queue->tasks[queue->priority]);
508 rpc_reset_waitqueue_priority(queue);
512 rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
517 static struct rpc_task *__rpc_find_next_queued(struct rpc_wait_queue *queue)
519 if (RPC_IS_PRIORITY(queue))
520 return __rpc_find_next_queued_priority(queue);
521 if (!list_empty(&queue->tasks[0]))
522 return list_first_entry(&queue->tasks[0], struct rpc_task, u.tk_wait.list);
527 * Wake up the first task on the wait queue.
529 struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue,
530 bool (*func)(struct rpc_task *, void *), void *data)
532 struct rpc_task *task = NULL;
534 dprintk("RPC: wake_up_first(%p \"%s\")\n",
535 queue, rpc_qname(queue));
536 spin_lock_bh(&queue->lock);
537 task = __rpc_find_next_queued(queue);
539 if (func(task, data))
540 rpc_wake_up_task_queue_locked(queue, task);
544 spin_unlock_bh(&queue->lock);
548 EXPORT_SYMBOL_GPL(rpc_wake_up_first);
550 static bool rpc_wake_up_next_func(struct rpc_task *task, void *data)
556 * Wake up the next task on the wait queue.
558 struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *queue)
560 return rpc_wake_up_first(queue, rpc_wake_up_next_func, NULL);
562 EXPORT_SYMBOL_GPL(rpc_wake_up_next);
565 * rpc_wake_up - wake up all rpc_tasks
566 * @queue: rpc_wait_queue on which the tasks are sleeping
570 void rpc_wake_up(struct rpc_wait_queue *queue)
572 struct list_head *head;
574 spin_lock_bh(&queue->lock);
575 head = &queue->tasks[queue->maxpriority];
577 while (!list_empty(head)) {
578 struct rpc_task *task;
579 task = list_first_entry(head,
582 rpc_wake_up_task_queue_locked(queue, task);
584 if (head == &queue->tasks[0])
588 spin_unlock_bh(&queue->lock);
590 EXPORT_SYMBOL_GPL(rpc_wake_up);
593 * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
594 * @queue: rpc_wait_queue on which the tasks are sleeping
595 * @status: status value to set
599 void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
601 struct list_head *head;
603 spin_lock_bh(&queue->lock);
604 head = &queue->tasks[queue->maxpriority];
606 while (!list_empty(head)) {
607 struct rpc_task *task;
608 task = list_first_entry(head,
611 task->tk_status = status;
612 rpc_wake_up_task_queue_locked(queue, task);
614 if (head == &queue->tasks[0])
618 spin_unlock_bh(&queue->lock);
620 EXPORT_SYMBOL_GPL(rpc_wake_up_status);
622 static void __rpc_queue_timer_fn(unsigned long ptr)
624 struct rpc_wait_queue *queue = (struct rpc_wait_queue *)ptr;
625 struct rpc_task *task, *n;
626 unsigned long expires, now, timeo;
628 spin_lock(&queue->lock);
629 expires = now = jiffies;
630 list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) {
631 timeo = task->u.tk_wait.expires;
632 if (time_after_eq(now, timeo)) {
633 dprintk("RPC: %5u timeout\n", task->tk_pid);
634 task->tk_status = -ETIMEDOUT;
635 rpc_wake_up_task_queue_locked(queue, task);
638 if (expires == now || time_after(expires, timeo))
641 if (!list_empty(&queue->timer_list.list))
642 rpc_set_queue_timer(queue, expires);
643 spin_unlock(&queue->lock);
646 static void __rpc_atrun(struct rpc_task *task)
648 if (task->tk_status == -ETIMEDOUT)
653 * Run a task at a later time
655 void rpc_delay(struct rpc_task *task, unsigned long delay)
657 task->tk_timeout = delay;
658 rpc_sleep_on(&delay_queue, task, __rpc_atrun);
660 EXPORT_SYMBOL_GPL(rpc_delay);
663 * Helper to call task->tk_ops->rpc_call_prepare
665 void rpc_prepare_task(struct rpc_task *task)
667 task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
671 rpc_init_task_statistics(struct rpc_task *task)
673 /* Initialize retry counters */
674 task->tk_garb_retry = 2;
675 task->tk_cred_retry = 2;
676 task->tk_rebind_retry = 2;
678 /* starting timestamp */
679 task->tk_start = ktime_get();
683 rpc_reset_task_statistics(struct rpc_task *task)
685 task->tk_timeouts = 0;
686 task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_KILLED|RPC_TASK_SENT);
688 rpc_init_task_statistics(task);
692 * Helper that calls task->tk_ops->rpc_call_done if it exists
694 void rpc_exit_task(struct rpc_task *task)
696 task->tk_action = NULL;
697 if (task->tk_ops->rpc_call_done != NULL) {
698 task->tk_ops->rpc_call_done(task, task->tk_calldata);
699 if (task->tk_action != NULL) {
700 WARN_ON(RPC_ASSASSINATED(task));
701 /* Always release the RPC slot and buffer memory */
703 rpc_reset_task_statistics(task);
708 void rpc_exit(struct rpc_task *task, int status)
710 task->tk_status = status;
711 task->tk_action = rpc_exit_task;
712 if (RPC_IS_QUEUED(task))
713 rpc_wake_up_queued_task(task->tk_waitqueue, task);
715 EXPORT_SYMBOL_GPL(rpc_exit);
717 void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
719 if (ops->rpc_release != NULL)
720 ops->rpc_release(calldata);
724 * This is the RPC `scheduler' (or rather, the finite state machine).
726 static void __rpc_execute(struct rpc_task *task)
728 struct rpc_wait_queue *queue;
729 int task_is_async = RPC_IS_ASYNC(task);
732 dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
733 task->tk_pid, task->tk_flags);
735 WARN_ON_ONCE(RPC_IS_QUEUED(task));
736 if (RPC_IS_QUEUED(task))
740 void (*do_action)(struct rpc_task *);
743 * Execute any pending callback first.
745 do_action = task->tk_callback;
746 task->tk_callback = NULL;
747 if (do_action == NULL) {
749 * Perform the next FSM step.
750 * tk_action may be NULL if the task has been killed.
751 * In particular, note that rpc_killall_tasks may
752 * do this at any time, so beware when dereferencing.
754 do_action = task->tk_action;
755 if (do_action == NULL)
758 trace_rpc_task_run_action(task->tk_client, task, task->tk_action);
762 * Lockless check for whether task is sleeping or not.
764 if (!RPC_IS_QUEUED(task))
767 * The queue->lock protects against races with
768 * rpc_make_runnable().
770 * Note that once we clear RPC_TASK_RUNNING on an asynchronous
771 * rpc_task, rpc_make_runnable() can assign it to a
772 * different workqueue. We therefore cannot assume that the
773 * rpc_task pointer may still be dereferenced.
775 queue = task->tk_waitqueue;
776 spin_lock_bh(&queue->lock);
777 if (!RPC_IS_QUEUED(task)) {
778 spin_unlock_bh(&queue->lock);
781 rpc_clear_running(task);
782 spin_unlock_bh(&queue->lock);
786 /* sync task: sleep here */
787 dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid);
788 status = out_of_line_wait_on_bit(&task->tk_runstate,
789 RPC_TASK_QUEUED, rpc_wait_bit_killable,
791 if (status == -ERESTARTSYS) {
793 * When a sync task receives a signal, it exits with
794 * -ERESTARTSYS. In order to catch any callbacks that
795 * clean up after sleeping on some queue, we don't
796 * break the loop here, but go around once more.
798 dprintk("RPC: %5u got signal\n", task->tk_pid);
799 task->tk_flags |= RPC_TASK_KILLED;
800 rpc_exit(task, -ERESTARTSYS);
802 dprintk("RPC: %5u sync task resuming\n", task->tk_pid);
805 dprintk("RPC: %5u return %d, status %d\n", task->tk_pid, status,
807 /* Release all resources associated with the task */
808 rpc_release_task(task);
812 * User-visible entry point to the scheduler.
814 * This may be called recursively if e.g. an async NFS task updates
815 * the attributes and finds that dirty pages must be flushed.
816 * NOTE: Upon exit of this function the task is guaranteed to be
817 * released. In particular note that tk_release() will have
818 * been called, so your task memory may have been freed.
820 void rpc_execute(struct rpc_task *task)
822 bool is_async = RPC_IS_ASYNC(task);
824 rpc_set_active(task);
825 rpc_make_runnable(task);
830 static void rpc_async_schedule(struct work_struct *work)
832 __rpc_execute(container_of(work, struct rpc_task, u.tk_work));
836 * rpc_malloc - allocate an RPC buffer
837 * @task: RPC task that will use this buffer
838 * @size: requested byte size
840 * To prevent rpciod from hanging, this allocator never sleeps,
841 * returning NULL and suppressing warning if the request cannot be serviced
843 * The caller can arrange to sleep in a way that is safe for rpciod.
845 * Most requests are 'small' (under 2KiB) and can be serviced from a
846 * mempool, ensuring that NFS reads and writes can always proceed,
847 * and that there is good locality of reference for these buffers.
849 * In order to avoid memory starvation triggering more writebacks of
850 * NFS requests, we avoid using GFP_KERNEL.
852 void *rpc_malloc(struct rpc_task *task, size_t size)
854 struct rpc_buffer *buf;
855 gfp_t gfp = GFP_NOIO | __GFP_NOWARN;
857 if (RPC_IS_SWAPPER(task))
858 gfp = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
860 size += sizeof(struct rpc_buffer);
861 if (size <= RPC_BUFFER_MAXSIZE)
862 buf = mempool_alloc(rpc_buffer_mempool, gfp);
864 buf = kmalloc(size, gfp);
870 dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
871 task->tk_pid, size, buf);
874 EXPORT_SYMBOL_GPL(rpc_malloc);
877 * rpc_free - free buffer allocated via rpc_malloc
878 * @buffer: buffer to free
881 void rpc_free(void *buffer)
884 struct rpc_buffer *buf;
889 buf = container_of(buffer, struct rpc_buffer, data);
892 dprintk("RPC: freeing buffer of size %zu at %p\n",
895 if (size <= RPC_BUFFER_MAXSIZE)
896 mempool_free(buf, rpc_buffer_mempool);
900 EXPORT_SYMBOL_GPL(rpc_free);
903 * Creation and deletion of RPC task structures
905 static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *task_setup_data)
907 memset(task, 0, sizeof(*task));
908 atomic_set(&task->tk_count, 1);
909 task->tk_flags = task_setup_data->flags;
910 task->tk_ops = task_setup_data->callback_ops;
911 task->tk_calldata = task_setup_data->callback_data;
912 INIT_LIST_HEAD(&task->tk_task);
914 task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW;
915 task->tk_owner = current->tgid;
917 /* Initialize workqueue for async tasks */
918 task->tk_workqueue = task_setup_data->workqueue;
920 if (task->tk_ops->rpc_call_prepare != NULL)
921 task->tk_action = rpc_prepare_task;
923 rpc_init_task_statistics(task);
925 dprintk("RPC: new task initialized, procpid %u\n",
926 task_pid_nr(current));
929 static struct rpc_task *
932 return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOIO);
936 * Create a new task for the specified client.
938 struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
940 struct rpc_task *task = setup_data->task;
941 unsigned short flags = 0;
944 task = rpc_alloc_task();
946 rpc_release_calldata(setup_data->callback_ops,
947 setup_data->callback_data);
948 return ERR_PTR(-ENOMEM);
950 flags = RPC_TASK_DYNAMIC;
953 rpc_init_task(task, setup_data);
954 task->tk_flags |= flags;
955 dprintk("RPC: allocated task %p\n", task);
960 * rpc_free_task - release rpc task and perform cleanups
962 * Note that we free up the rpc_task _after_ rpc_release_calldata()
963 * in order to work around a workqueue dependency issue.
966 * "Workqueue currently considers two work items to be the same if they're
967 * on the same address and won't execute them concurrently - ie. it
968 * makes a work item which is queued again while being executed wait
969 * for the previous execution to complete.
971 * If a work function frees the work item, and then waits for an event
972 * which should be performed by another work item and *that* work item
973 * recycles the freed work item, it can create a false dependency loop.
974 * There really is no reliable way to detect this short of verifying
975 * every memory free."
978 static void rpc_free_task(struct rpc_task *task)
980 unsigned short tk_flags = task->tk_flags;
982 rpc_release_calldata(task->tk_ops, task->tk_calldata);
984 if (tk_flags & RPC_TASK_DYNAMIC) {
985 dprintk("RPC: %5u freeing task\n", task->tk_pid);
986 mempool_free(task, rpc_task_mempool);
990 static void rpc_async_release(struct work_struct *work)
992 rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
995 static void rpc_release_resources_task(struct rpc_task *task)
998 if (task->tk_msg.rpc_cred) {
999 put_rpccred(task->tk_msg.rpc_cred);
1000 task->tk_msg.rpc_cred = NULL;
1002 rpc_task_release_client(task);
1005 static void rpc_final_put_task(struct rpc_task *task,
1006 struct workqueue_struct *q)
1009 INIT_WORK(&task->u.tk_work, rpc_async_release);
1010 queue_work(q, &task->u.tk_work);
1012 rpc_free_task(task);
1015 static void rpc_do_put_task(struct rpc_task *task, struct workqueue_struct *q)
1017 if (atomic_dec_and_test(&task->tk_count)) {
1018 rpc_release_resources_task(task);
1019 rpc_final_put_task(task, q);
1023 void rpc_put_task(struct rpc_task *task)
1025 rpc_do_put_task(task, NULL);
1027 EXPORT_SYMBOL_GPL(rpc_put_task);
1029 void rpc_put_task_async(struct rpc_task *task)
1031 rpc_do_put_task(task, task->tk_workqueue);
1033 EXPORT_SYMBOL_GPL(rpc_put_task_async);
1035 static void rpc_release_task(struct rpc_task *task)
1037 dprintk("RPC: %5u release task\n", task->tk_pid);
1039 WARN_ON_ONCE(RPC_IS_QUEUED(task));
1041 rpc_release_resources_task(task);
1044 * Note: at this point we have been removed from rpc_clnt->cl_tasks,
1045 * so it should be safe to use task->tk_count as a test for whether
1046 * or not any other processes still hold references to our rpc_task.
1048 if (atomic_read(&task->tk_count) != 1 + !RPC_IS_ASYNC(task)) {
1049 /* Wake up anyone who may be waiting for task completion */
1050 if (!rpc_complete_task(task))
1053 if (!atomic_dec_and_test(&task->tk_count))
1056 rpc_final_put_task(task, task->tk_workqueue);
1061 return try_module_get(THIS_MODULE) ? 0 : -EINVAL;
1064 void rpciod_down(void)
1066 module_put(THIS_MODULE);
1070 * Start up the rpciod workqueue.
1072 static int rpciod_start(void)
1074 struct workqueue_struct *wq;
1077 * Create the rpciod thread and wait for it to start.
1079 dprintk("RPC: creating workqueue rpciod\n");
1080 /* Note: highpri because network receive is latency sensitive */
1081 wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
1082 rpciod_workqueue = wq;
1083 return rpciod_workqueue != NULL;
1086 static void rpciod_stop(void)
1088 struct workqueue_struct *wq = NULL;
1090 if (rpciod_workqueue == NULL)
1092 dprintk("RPC: destroying workqueue rpciod\n");
1094 wq = rpciod_workqueue;
1095 rpciod_workqueue = NULL;
1096 destroy_workqueue(wq);
1100 rpc_destroy_mempool(void)
1103 mempool_destroy(rpc_buffer_mempool);
1104 mempool_destroy(rpc_task_mempool);
1105 kmem_cache_destroy(rpc_task_slabp);
1106 kmem_cache_destroy(rpc_buffer_slabp);
1107 rpc_destroy_wait_queue(&delay_queue);
1111 rpc_init_mempool(void)
1114 * The following is not strictly a mempool initialisation,
1115 * but there is no harm in doing it here
1117 rpc_init_wait_queue(&delay_queue, "delayq");
1118 if (!rpciod_start())
1121 rpc_task_slabp = kmem_cache_create("rpc_tasks",
1122 sizeof(struct rpc_task),
1123 0, SLAB_HWCACHE_ALIGN,
1125 if (!rpc_task_slabp)
1127 rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1129 0, SLAB_HWCACHE_ALIGN,
1131 if (!rpc_buffer_slabp)
1133 rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
1135 if (!rpc_task_mempool)
1137 rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
1139 if (!rpc_buffer_mempool)
1143 rpc_destroy_mempool();