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1/*
2 * linux/net/sunrpc/sched.c
3 *
4 * Scheduling for synchronous and asynchronous RPC requests.
5 *
6 * Copyright (C) 1996 Olaf Kirch, <okir@monad.swb.de>
7 *
8 * TCP NFS related read + write fixes
9 * (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
10 */
11
12#include <linux/module.h>
13
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>
22
23#include <linux/sunrpc/clnt.h>
24
25#include "sunrpc.h"
26
27#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
28#define RPCDBG_FACILITY RPCDBG_SCHED
29#endif
30
31#define CREATE_TRACE_POINTS
32#include <trace/events/sunrpc.h>
33
34/*
35 * RPC slabs and memory pools
36 */
37#define RPC_BUFFER_MAXSIZE (2048)
38#define RPC_BUFFER_POOLSIZE (8)
39#define RPC_TASK_POOLSIZE (8)
40static struct kmem_cache *rpc_task_slabp __read_mostly;
41static struct kmem_cache *rpc_buffer_slabp __read_mostly;
42static mempool_t *rpc_task_mempool __read_mostly;
43static mempool_t *rpc_buffer_mempool __read_mostly;
44
45static void rpc_async_schedule(struct work_struct *);
46static void rpc_release_task(struct rpc_task *task);
47static void __rpc_queue_timer_fn(unsigned long ptr);
48
49/*
50 * RPC tasks sit here while waiting for conditions to improve.
51 */
52static struct rpc_wait_queue delay_queue;
53
54/*
55 * rpciod-related stuff
56 */
57struct workqueue_struct *rpciod_workqueue;
58
59/*
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
62 * rpc_run_timer().
63 */
64static void
65__rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
66{
67 if (task->tk_timeout == 0)
68 return;
69 dprintk("RPC: %5u disabling timer\n", task->tk_pid);
70 task->tk_timeout = 0;
71 list_del(&task->u.tk_wait.timer_list);
72 if (list_empty(&queue->timer_list.list))
73 del_timer(&queue->timer_list.timer);
74}
75
76static void
77rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)
78{
79 queue->timer_list.expires = expires;
80 mod_timer(&queue->timer_list.timer, expires);
81}
82
83/*
84 * Set up a timer for the current task.
85 */
86static void
87__rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
88{
89 if (!task->tk_timeout)
90 return;
91
92 dprintk("RPC: %5u setting alarm for %u ms\n",
93 task->tk_pid, jiffies_to_msecs(task->tk_timeout));
94
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);
99}
100
101static void rpc_rotate_queue_owner(struct rpc_wait_queue *queue)
102{
103 struct list_head *q = &queue->tasks[queue->priority];
104 struct rpc_task *task;
105
106 if (!list_empty(q)) {
107 task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
108 if (task->tk_owner == queue->owner)
109 list_move_tail(&task->u.tk_wait.list, q);
110 }
111}
112
113static void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
114{
115 if (queue->priority != priority) {
116 /* Fairness: rotate the list when changing priority */
117 rpc_rotate_queue_owner(queue);
118 queue->priority = priority;
119 }
120}
121
122static void rpc_set_waitqueue_owner(struct rpc_wait_queue *queue, pid_t pid)
123{
124 queue->owner = pid;
125 queue->nr = RPC_BATCH_COUNT;
126}
127
128static void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
129{
130 rpc_set_waitqueue_priority(queue, queue->maxpriority);
131 rpc_set_waitqueue_owner(queue, 0);
132}
133
134/*
135 * Add new request to a priority queue.
136 */
137static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue,
138 struct rpc_task *task,
139 unsigned char queue_priority)
140{
141 struct list_head *q;
142 struct rpc_task *t;
143
144 INIT_LIST_HEAD(&task->u.tk_wait.links);
145 if (unlikely(queue_priority > queue->maxpriority))
146 queue_priority = queue->maxpriority;
147 if (queue_priority > queue->priority)
148 rpc_set_waitqueue_priority(queue, queue_priority);
149 q = &queue->tasks[queue_priority];
150 list_for_each_entry(t, q, u.tk_wait.list) {
151 if (t->tk_owner == task->tk_owner) {
152 list_add_tail(&task->u.tk_wait.list, &t->u.tk_wait.links);
153 return;
154 }
155 }
156 list_add_tail(&task->u.tk_wait.list, q);
157}
158
159/*
160 * Add new request to wait queue.
161 *
162 * Swapper tasks always get inserted at the head of the queue.
163 * This should avoid many nasty memory deadlocks and hopefully
164 * improve overall performance.
165 * Everyone else gets appended to the queue to ensure proper FIFO behavior.
166 */
167static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
168 struct rpc_task *task,
169 unsigned char queue_priority)
170{
171 WARN_ON_ONCE(RPC_IS_QUEUED(task));
172 if (RPC_IS_QUEUED(task))
173 return;
174
175 if (RPC_IS_PRIORITY(queue))
176 __rpc_add_wait_queue_priority(queue, task, queue_priority);
177 else if (RPC_IS_SWAPPER(task))
178 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
179 else
180 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
181 task->tk_waitqueue = queue;
182 queue->qlen++;
183 /* barrier matches the read in rpc_wake_up_task_queue_locked() */
184 smp_wmb();
185 rpc_set_queued(task);
186
187 dprintk("RPC: %5u added to queue %p \"%s\"\n",
188 task->tk_pid, queue, rpc_qname(queue));
189}
190
191/*
192 * Remove request from a priority queue.
193 */
194static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
195{
196 struct rpc_task *t;
197
198 if (!list_empty(&task->u.tk_wait.links)) {
199 t = list_entry(task->u.tk_wait.links.next, struct rpc_task, u.tk_wait.list);
200 list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);
201 list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);
202 }
203}
204
205/*
206 * Remove request from queue.
207 * Note: must be called with spin lock held.
208 */
209static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
210{
211 __rpc_disable_timer(queue, task);
212 if (RPC_IS_PRIORITY(queue))
213 __rpc_remove_wait_queue_priority(task);
214 list_del(&task->u.tk_wait.list);
215 queue->qlen--;
216 dprintk("RPC: %5u removed from queue %p \"%s\"\n",
217 task->tk_pid, queue, rpc_qname(queue));
218}
219
220static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
221{
222 int i;
223
224 spin_lock_init(&queue->lock);
225 for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
226 INIT_LIST_HEAD(&queue->tasks[i]);
227 queue->maxpriority = nr_queues - 1;
228 rpc_reset_waitqueue_priority(queue);
229 queue->qlen = 0;
230 setup_timer(&queue->timer_list.timer, __rpc_queue_timer_fn, (unsigned long)queue);
231 INIT_LIST_HEAD(&queue->timer_list.list);
232 rpc_assign_waitqueue_name(queue, qname);
233}
234
235void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
236{
237 __rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY);
238}
239EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue);
240
241void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
242{
243 __rpc_init_priority_wait_queue(queue, qname, 1);
244}
245EXPORT_SYMBOL_GPL(rpc_init_wait_queue);
246
247void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)
248{
249 del_timer_sync(&queue->timer_list.timer);
250}
251EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
252
253static int rpc_wait_bit_killable(struct wait_bit_key *key, int mode)
254{
255 freezable_schedule_unsafe();
256 if (signal_pending_state(mode, current))
257 return -ERESTARTSYS;
258 return 0;
259}
260
261#if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS)
262static void rpc_task_set_debuginfo(struct rpc_task *task)
263{
264 static atomic_t rpc_pid;
265
266 task->tk_pid = atomic_inc_return(&rpc_pid);
267}
268#else
269static inline void rpc_task_set_debuginfo(struct rpc_task *task)
270{
271}
272#endif
273
274static void rpc_set_active(struct rpc_task *task)
275{
276 trace_rpc_task_begin(task->tk_client, task, NULL);
277
278 rpc_task_set_debuginfo(task);
279 set_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
280}
281
282/*
283 * Mark an RPC call as having completed by clearing the 'active' bit
284 * and then waking up all tasks that were sleeping.
285 */
286static int rpc_complete_task(struct rpc_task *task)
287{
288 void *m = &task->tk_runstate;
289 wait_queue_head_t *wq = bit_waitqueue(m, RPC_TASK_ACTIVE);
290 struct wait_bit_key k = __WAIT_BIT_KEY_INITIALIZER(m, RPC_TASK_ACTIVE);
291 unsigned long flags;
292 int ret;
293
294 trace_rpc_task_complete(task->tk_client, task, NULL);
295
296 spin_lock_irqsave(&wq->lock, flags);
297 clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
298 ret = atomic_dec_and_test(&task->tk_count);
299 if (waitqueue_active(wq))
300 __wake_up_locked_key(wq, TASK_NORMAL, &k);
301 spin_unlock_irqrestore(&wq->lock, flags);
302 return ret;
303}
304
305/*
306 * Allow callers to wait for completion of an RPC call
307 *
308 * Note the use of out_of_line_wait_on_bit() rather than wait_on_bit()
309 * to enforce taking of the wq->lock and hence avoid races with
310 * rpc_complete_task().
311 */
312int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *action)
313{
314 if (action == NULL)
315 action = rpc_wait_bit_killable;
316 return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
317 action, TASK_KILLABLE);
318}
319EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
320
321/*
322 * Make an RPC task runnable.
323 *
324 * Note: If the task is ASYNC, and is being made runnable after sitting on an
325 * rpc_wait_queue, this must be called with the queue spinlock held to protect
326 * the wait queue operation.
327 * Note the ordering of rpc_test_and_set_running() and rpc_clear_queued(),
328 * which is needed to ensure that __rpc_execute() doesn't loop (due to the
329 * lockless RPC_IS_QUEUED() test) before we've had a chance to test
330 * the RPC_TASK_RUNNING flag.
331 */
332static void rpc_make_runnable(struct rpc_task *task)
333{
334 bool need_wakeup = !rpc_test_and_set_running(task);
335
336 rpc_clear_queued(task);
337 if (!need_wakeup)
338 return;
339 if (RPC_IS_ASYNC(task)) {
340 INIT_WORK(&task->u.tk_work, rpc_async_schedule);
341 queue_work(rpciod_workqueue, &task->u.tk_work);
342 } else
343 wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
344}
345
346/*
347 * Prepare for sleeping on a wait queue.
348 * By always appending tasks to the list we ensure FIFO behavior.
349 * NB: An RPC task will only receive interrupt-driven events as long
350 * as it's on a wait queue.
351 */
352static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
353 struct rpc_task *task,
354 rpc_action action,
355 unsigned char queue_priority)
356{
357 dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n",
358 task->tk_pid, rpc_qname(q), jiffies);
359
360 trace_rpc_task_sleep(task->tk_client, task, q);
361
362 __rpc_add_wait_queue(q, task, queue_priority);
363
364 WARN_ON_ONCE(task->tk_callback != NULL);
365 task->tk_callback = action;
366 __rpc_add_timer(q, task);
367}
368
369void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
370 rpc_action action)
371{
372 /* We shouldn't ever put an inactive task to sleep */
373 WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
374 if (!RPC_IS_ACTIVATED(task)) {
375 task->tk_status = -EIO;
376 rpc_put_task_async(task);
377 return;
378 }
379
380 /*
381 * Protect the queue operations.
382 */
383 spin_lock_bh(&q->lock);
384 __rpc_sleep_on_priority(q, task, action, task->tk_priority);
385 spin_unlock_bh(&q->lock);
386}
387EXPORT_SYMBOL_GPL(rpc_sleep_on);
388
389void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
390 rpc_action action, int priority)
391{
392 /* We shouldn't ever put an inactive task to sleep */
393 WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
394 if (!RPC_IS_ACTIVATED(task)) {
395 task->tk_status = -EIO;
396 rpc_put_task_async(task);
397 return;
398 }
399
400 /*
401 * Protect the queue operations.
402 */
403 spin_lock_bh(&q->lock);
404 __rpc_sleep_on_priority(q, task, action, priority - RPC_PRIORITY_LOW);
405 spin_unlock_bh(&q->lock);
406}
407EXPORT_SYMBOL_GPL(rpc_sleep_on_priority);
408
409/**
410 * __rpc_do_wake_up_task - wake up a single rpc_task
411 * @queue: wait queue
412 * @task: task to be woken up
413 *
414 * Caller must hold queue->lock, and have cleared the task queued flag.
415 */
416static void __rpc_do_wake_up_task(struct rpc_wait_queue *queue, struct rpc_task *task)
417{
418 dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
419 task->tk_pid, jiffies);
420
421 /* Has the task been executed yet? If not, we cannot wake it up! */
422 if (!RPC_IS_ACTIVATED(task)) {
423 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
424 return;
425 }
426
427 trace_rpc_task_wakeup(task->tk_client, task, queue);
428
429 __rpc_remove_wait_queue(queue, task);
430
431 rpc_make_runnable(task);
432
433 dprintk("RPC: __rpc_wake_up_task done\n");
434}
435
436/*
437 * Wake up a queued task while the queue lock is being held
438 */
439static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
440{
441 if (RPC_IS_QUEUED(task)) {
442 smp_rmb();
443 if (task->tk_waitqueue == queue)
444 __rpc_do_wake_up_task(queue, task);
445 }
446}
447
448/*
449 * Wake up a task on a specific queue
450 */
451void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
452{
453 spin_lock_bh(&queue->lock);
454 rpc_wake_up_task_queue_locked(queue, task);
455 spin_unlock_bh(&queue->lock);
456}
457EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
458
459/*
460 * Wake up the next task on a priority queue.
461 */
462static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *queue)
463{
464 struct list_head *q;
465 struct rpc_task *task;
466
467 /*
468 * Service a batch of tasks from a single owner.
469 */
470 q = &queue->tasks[queue->priority];
471 if (!list_empty(q)) {
472 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
473 if (queue->owner == task->tk_owner) {
474 if (--queue->nr)
475 goto out;
476 list_move_tail(&task->u.tk_wait.list, q);
477 }
478 /*
479 * Check if we need to switch queues.
480 */
481 goto new_owner;
482 }
483
484 /*
485 * Service the next queue.
486 */
487 do {
488 if (q == &queue->tasks[0])
489 q = &queue->tasks[queue->maxpriority];
490 else
491 q = q - 1;
492 if (!list_empty(q)) {
493 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
494 goto new_queue;
495 }
496 } while (q != &queue->tasks[queue->priority]);
497
498 rpc_reset_waitqueue_priority(queue);
499 return NULL;
500
501new_queue:
502 rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
503new_owner:
504 rpc_set_waitqueue_owner(queue, task->tk_owner);
505out:
506 return task;
507}
508
509static struct rpc_task *__rpc_find_next_queued(struct rpc_wait_queue *queue)
510{
511 if (RPC_IS_PRIORITY(queue))
512 return __rpc_find_next_queued_priority(queue);
513 if (!list_empty(&queue->tasks[0]))
514 return list_first_entry(&queue->tasks[0], struct rpc_task, u.tk_wait.list);
515 return NULL;
516}
517
518/*
519 * Wake up the first task on the wait queue.
520 */
521struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue,
522 bool (*func)(struct rpc_task *, void *), void *data)
523{
524 struct rpc_task *task = NULL;
525
526 dprintk("RPC: wake_up_first(%p \"%s\")\n",
527 queue, rpc_qname(queue));
528 spin_lock_bh(&queue->lock);
529 task = __rpc_find_next_queued(queue);
530 if (task != NULL) {
531 if (func(task, data))
532 rpc_wake_up_task_queue_locked(queue, task);
533 else
534 task = NULL;
535 }
536 spin_unlock_bh(&queue->lock);
537
538 return task;
539}
540EXPORT_SYMBOL_GPL(rpc_wake_up_first);
541
542static bool rpc_wake_up_next_func(struct rpc_task *task, void *data)
543{
544 return true;
545}
546
547/*
548 * Wake up the next task on the wait queue.
549*/
550struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *queue)
551{
552 return rpc_wake_up_first(queue, rpc_wake_up_next_func, NULL);
553}
554EXPORT_SYMBOL_GPL(rpc_wake_up_next);
555
556/**
557 * rpc_wake_up - wake up all rpc_tasks
558 * @queue: rpc_wait_queue on which the tasks are sleeping
559 *
560 * Grabs queue->lock
561 */
562void rpc_wake_up(struct rpc_wait_queue *queue)
563{
564 struct list_head *head;
565
566 spin_lock_bh(&queue->lock);
567 head = &queue->tasks[queue->maxpriority];
568 for (;;) {
569 while (!list_empty(head)) {
570 struct rpc_task *task;
571 task = list_first_entry(head,
572 struct rpc_task,
573 u.tk_wait.list);
574 rpc_wake_up_task_queue_locked(queue, task);
575 }
576 if (head == &queue->tasks[0])
577 break;
578 head--;
579 }
580 spin_unlock_bh(&queue->lock);
581}
582EXPORT_SYMBOL_GPL(rpc_wake_up);
583
584/**
585 * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
586 * @queue: rpc_wait_queue on which the tasks are sleeping
587 * @status: status value to set
588 *
589 * Grabs queue->lock
590 */
591void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
592{
593 struct list_head *head;
594
595 spin_lock_bh(&queue->lock);
596 head = &queue->tasks[queue->maxpriority];
597 for (;;) {
598 while (!list_empty(head)) {
599 struct rpc_task *task;
600 task = list_first_entry(head,
601 struct rpc_task,
602 u.tk_wait.list);
603 task->tk_status = status;
604 rpc_wake_up_task_queue_locked(queue, task);
605 }
606 if (head == &queue->tasks[0])
607 break;
608 head--;
609 }
610 spin_unlock_bh(&queue->lock);
611}
612EXPORT_SYMBOL_GPL(rpc_wake_up_status);
613
614static void __rpc_queue_timer_fn(unsigned long ptr)
615{
616 struct rpc_wait_queue *queue = (struct rpc_wait_queue *)ptr;
617 struct rpc_task *task, *n;
618 unsigned long expires, now, timeo;
619
620 spin_lock(&queue->lock);
621 expires = now = jiffies;
622 list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) {
623 timeo = task->u.tk_wait.expires;
624 if (time_after_eq(now, timeo)) {
625 dprintk("RPC: %5u timeout\n", task->tk_pid);
626 task->tk_status = -ETIMEDOUT;
627 rpc_wake_up_task_queue_locked(queue, task);
628 continue;
629 }
630 if (expires == now || time_after(expires, timeo))
631 expires = timeo;
632 }
633 if (!list_empty(&queue->timer_list.list))
634 rpc_set_queue_timer(queue, expires);
635 spin_unlock(&queue->lock);
636}
637
638static void __rpc_atrun(struct rpc_task *task)
639{
640 if (task->tk_status == -ETIMEDOUT)
641 task->tk_status = 0;
642}
643
644/*
645 * Run a task at a later time
646 */
647void rpc_delay(struct rpc_task *task, unsigned long delay)
648{
649 task->tk_timeout = delay;
650 rpc_sleep_on(&delay_queue, task, __rpc_atrun);
651}
652EXPORT_SYMBOL_GPL(rpc_delay);
653
654/*
655 * Helper to call task->tk_ops->rpc_call_prepare
656 */
657void rpc_prepare_task(struct rpc_task *task)
658{
659 task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
660}
661
662static void
663rpc_init_task_statistics(struct rpc_task *task)
664{
665 /* Initialize retry counters */
666 task->tk_garb_retry = 2;
667 task->tk_cred_retry = 2;
668 task->tk_rebind_retry = 2;
669
670 /* starting timestamp */
671 task->tk_start = ktime_get();
672}
673
674static void
675rpc_reset_task_statistics(struct rpc_task *task)
676{
677 task->tk_timeouts = 0;
678 task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_KILLED|RPC_TASK_SENT);
679
680 rpc_init_task_statistics(task);
681}
682
683/*
684 * Helper that calls task->tk_ops->rpc_call_done if it exists
685 */
686void rpc_exit_task(struct rpc_task *task)
687{
688 task->tk_action = NULL;
689 if (task->tk_ops->rpc_call_done != NULL) {
690 task->tk_ops->rpc_call_done(task, task->tk_calldata);
691 if (task->tk_action != NULL) {
692 WARN_ON(RPC_ASSASSINATED(task));
693 /* Always release the RPC slot and buffer memory */
694 xprt_release(task);
695 rpc_reset_task_statistics(task);
696 }
697 }
698}
699
700void rpc_exit(struct rpc_task *task, int status)
701{
702 task->tk_status = status;
703 task->tk_action = rpc_exit_task;
704 if (RPC_IS_QUEUED(task))
705 rpc_wake_up_queued_task(task->tk_waitqueue, task);
706}
707EXPORT_SYMBOL_GPL(rpc_exit);
708
709void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
710{
711 if (ops->rpc_release != NULL)
712 ops->rpc_release(calldata);
713}
714
715/*
716 * This is the RPC `scheduler' (or rather, the finite state machine).
717 */
718static void __rpc_execute(struct rpc_task *task)
719{
720 struct rpc_wait_queue *queue;
721 int task_is_async = RPC_IS_ASYNC(task);
722 int status = 0;
723
724 dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
725 task->tk_pid, task->tk_flags);
726
727 WARN_ON_ONCE(RPC_IS_QUEUED(task));
728 if (RPC_IS_QUEUED(task))
729 return;
730
731 for (;;) {
732 void (*do_action)(struct rpc_task *);
733
734 /*
735 * Execute any pending callback first.
736 */
737 do_action = task->tk_callback;
738 task->tk_callback = NULL;
739 if (do_action == NULL) {
740 /*
741 * Perform the next FSM step.
742 * tk_action may be NULL if the task has been killed.
743 * In particular, note that rpc_killall_tasks may
744 * do this at any time, so beware when dereferencing.
745 */
746 do_action = task->tk_action;
747 if (do_action == NULL)
748 break;
749 }
750 trace_rpc_task_run_action(task->tk_client, task, task->tk_action);
751 do_action(task);
752
753 /*
754 * Lockless check for whether task is sleeping or not.
755 */
756 if (!RPC_IS_QUEUED(task))
757 continue;
758 /*
759 * The queue->lock protects against races with
760 * rpc_make_runnable().
761 *
762 * Note that once we clear RPC_TASK_RUNNING on an asynchronous
763 * rpc_task, rpc_make_runnable() can assign it to a
764 * different workqueue. We therefore cannot assume that the
765 * rpc_task pointer may still be dereferenced.
766 */
767 queue = task->tk_waitqueue;
768 spin_lock_bh(&queue->lock);
769 if (!RPC_IS_QUEUED(task)) {
770 spin_unlock_bh(&queue->lock);
771 continue;
772 }
773 rpc_clear_running(task);
774 spin_unlock_bh(&queue->lock);
775 if (task_is_async)
776 return;
777
778 /* sync task: sleep here */
779 dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid);
780 status = out_of_line_wait_on_bit(&task->tk_runstate,
781 RPC_TASK_QUEUED, rpc_wait_bit_killable,
782 TASK_KILLABLE);
783 if (status == -ERESTARTSYS) {
784 /*
785 * When a sync task receives a signal, it exits with
786 * -ERESTARTSYS. In order to catch any callbacks that
787 * clean up after sleeping on some queue, we don't
788 * break the loop here, but go around once more.
789 */
790 dprintk("RPC: %5u got signal\n", task->tk_pid);
791 task->tk_flags |= RPC_TASK_KILLED;
792 rpc_exit(task, -ERESTARTSYS);
793 }
794 dprintk("RPC: %5u sync task resuming\n", task->tk_pid);
795 }
796
797 dprintk("RPC: %5u return %d, status %d\n", task->tk_pid, status,
798 task->tk_status);
799 /* Release all resources associated with the task */
800 rpc_release_task(task);
801}
802
803/*
804 * User-visible entry point to the scheduler.
805 *
806 * This may be called recursively if e.g. an async NFS task updates
807 * the attributes and finds that dirty pages must be flushed.
808 * NOTE: Upon exit of this function the task is guaranteed to be
809 * released. In particular note that tk_release() will have
810 * been called, so your task memory may have been freed.
811 */
812void rpc_execute(struct rpc_task *task)
813{
814 bool is_async = RPC_IS_ASYNC(task);
815
816 rpc_set_active(task);
817 rpc_make_runnable(task);
818 if (!is_async)
819 __rpc_execute(task);
820}
821
822static void rpc_async_schedule(struct work_struct *work)
823{
824 __rpc_execute(container_of(work, struct rpc_task, u.tk_work));
825}
826
827/**
828 * rpc_malloc - allocate an RPC buffer
829 * @task: RPC task that will use this buffer
830 * @size: requested byte size
831 *
832 * To prevent rpciod from hanging, this allocator never sleeps,
833 * returning NULL and suppressing warning if the request cannot be serviced
834 * immediately.
835 * The caller can arrange to sleep in a way that is safe for rpciod.
836 *
837 * Most requests are 'small' (under 2KiB) and can be serviced from a
838 * mempool, ensuring that NFS reads and writes can always proceed,
839 * and that there is good locality of reference for these buffers.
840 *
841 * In order to avoid memory starvation triggering more writebacks of
842 * NFS requests, we avoid using GFP_KERNEL.
843 */
844void *rpc_malloc(struct rpc_task *task, size_t size)
845{
846 struct rpc_buffer *buf;
847 gfp_t gfp = GFP_NOIO | __GFP_NOWARN;
848
849 if (RPC_IS_SWAPPER(task))
850 gfp = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
851
852 size += sizeof(struct rpc_buffer);
853 if (size <= RPC_BUFFER_MAXSIZE)
854 buf = mempool_alloc(rpc_buffer_mempool, gfp);
855 else
856 buf = kmalloc(size, gfp);
857
858 if (!buf)
859 return NULL;
860
861 buf->len = size;
862 dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
863 task->tk_pid, size, buf);
864 return &buf->data;
865}
866EXPORT_SYMBOL_GPL(rpc_malloc);
867
868/**
869 * rpc_free - free buffer allocated via rpc_malloc
870 * @buffer: buffer to free
871 *
872 */
873void rpc_free(void *buffer)
874{
875 size_t size;
876 struct rpc_buffer *buf;
877
878 if (!buffer)
879 return;
880
881 buf = container_of(buffer, struct rpc_buffer, data);
882 size = buf->len;
883
884 dprintk("RPC: freeing buffer of size %zu at %p\n",
885 size, buf);
886
887 if (size <= RPC_BUFFER_MAXSIZE)
888 mempool_free(buf, rpc_buffer_mempool);
889 else
890 kfree(buf);
891}
892EXPORT_SYMBOL_GPL(rpc_free);
893
894/*
895 * Creation and deletion of RPC task structures
896 */
897static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *task_setup_data)
898{
899 memset(task, 0, sizeof(*task));
900 atomic_set(&task->tk_count, 1);
901 task->tk_flags = task_setup_data->flags;
902 task->tk_ops = task_setup_data->callback_ops;
903 task->tk_calldata = task_setup_data->callback_data;
904 INIT_LIST_HEAD(&task->tk_task);
905
906 task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW;
907 task->tk_owner = current->tgid;
908
909 /* Initialize workqueue for async tasks */
910 task->tk_workqueue = task_setup_data->workqueue;
911
912 task->tk_xprt = xprt_get(task_setup_data->rpc_xprt);
913
914 if (task->tk_ops->rpc_call_prepare != NULL)
915 task->tk_action = rpc_prepare_task;
916
917 rpc_init_task_statistics(task);
918
919 dprintk("RPC: new task initialized, procpid %u\n",
920 task_pid_nr(current));
921}
922
923static struct rpc_task *
924rpc_alloc_task(void)
925{
926 return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOIO);
927}
928
929/*
930 * Create a new task for the specified client.
931 */
932struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
933{
934 struct rpc_task *task = setup_data->task;
935 unsigned short flags = 0;
936
937 if (task == NULL) {
938 task = rpc_alloc_task();
939 if (task == NULL) {
940 rpc_release_calldata(setup_data->callback_ops,
941 setup_data->callback_data);
942 return ERR_PTR(-ENOMEM);
943 }
944 flags = RPC_TASK_DYNAMIC;
945 }
946
947 rpc_init_task(task, setup_data);
948 task->tk_flags |= flags;
949 dprintk("RPC: allocated task %p\n", task);
950 return task;
951}
952
953/*
954 * rpc_free_task - release rpc task and perform cleanups
955 *
956 * Note that we free up the rpc_task _after_ rpc_release_calldata()
957 * in order to work around a workqueue dependency issue.
958 *
959 * Tejun Heo states:
960 * "Workqueue currently considers two work items to be the same if they're
961 * on the same address and won't execute them concurrently - ie. it
962 * makes a work item which is queued again while being executed wait
963 * for the previous execution to complete.
964 *
965 * If a work function frees the work item, and then waits for an event
966 * which should be performed by another work item and *that* work item
967 * recycles the freed work item, it can create a false dependency loop.
968 * There really is no reliable way to detect this short of verifying
969 * every memory free."
970 *
971 */
972static void rpc_free_task(struct rpc_task *task)
973{
974 unsigned short tk_flags = task->tk_flags;
975
976 rpc_release_calldata(task->tk_ops, task->tk_calldata);
977
978 if (tk_flags & RPC_TASK_DYNAMIC) {
979 dprintk("RPC: %5u freeing task\n", task->tk_pid);
980 mempool_free(task, rpc_task_mempool);
981 }
982}
983
984static void rpc_async_release(struct work_struct *work)
985{
986 rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
987}
988
989static void rpc_release_resources_task(struct rpc_task *task)
990{
991 xprt_release(task);
992 if (task->tk_msg.rpc_cred) {
993 put_rpccred(task->tk_msg.rpc_cred);
994 task->tk_msg.rpc_cred = NULL;
995 }
996 rpc_task_release_client(task);
997}
998
999static void rpc_final_put_task(struct rpc_task *task,
1000 struct workqueue_struct *q)
1001{
1002 if (q != NULL) {
1003 INIT_WORK(&task->u.tk_work, rpc_async_release);
1004 queue_work(q, &task->u.tk_work);
1005 } else
1006 rpc_free_task(task);
1007}
1008
1009static void rpc_do_put_task(struct rpc_task *task, struct workqueue_struct *q)
1010{
1011 if (atomic_dec_and_test(&task->tk_count)) {
1012 rpc_release_resources_task(task);
1013 rpc_final_put_task(task, q);
1014 }
1015}
1016
1017void rpc_put_task(struct rpc_task *task)
1018{
1019 rpc_do_put_task(task, NULL);
1020}
1021EXPORT_SYMBOL_GPL(rpc_put_task);
1022
1023void rpc_put_task_async(struct rpc_task *task)
1024{
1025 rpc_do_put_task(task, task->tk_workqueue);
1026}
1027EXPORT_SYMBOL_GPL(rpc_put_task_async);
1028
1029static void rpc_release_task(struct rpc_task *task)
1030{
1031 dprintk("RPC: %5u release task\n", task->tk_pid);
1032
1033 WARN_ON_ONCE(RPC_IS_QUEUED(task));
1034
1035 rpc_release_resources_task(task);
1036
1037 /*
1038 * Note: at this point we have been removed from rpc_clnt->cl_tasks,
1039 * so it should be safe to use task->tk_count as a test for whether
1040 * or not any other processes still hold references to our rpc_task.
1041 */
1042 if (atomic_read(&task->tk_count) != 1 + !RPC_IS_ASYNC(task)) {
1043 /* Wake up anyone who may be waiting for task completion */
1044 if (!rpc_complete_task(task))
1045 return;
1046 } else {
1047 if (!atomic_dec_and_test(&task->tk_count))
1048 return;
1049 }
1050 rpc_final_put_task(task, task->tk_workqueue);
1051}
1052
1053int rpciod_up(void)
1054{
1055 return try_module_get(THIS_MODULE) ? 0 : -EINVAL;
1056}
1057
1058void rpciod_down(void)
1059{
1060 module_put(THIS_MODULE);
1061}
1062
1063/*
1064 * Start up the rpciod workqueue.
1065 */
1066static int rpciod_start(void)
1067{
1068 struct workqueue_struct *wq;
1069
1070 /*
1071 * Create the rpciod thread and wait for it to start.
1072 */
1073 dprintk("RPC: creating workqueue rpciod\n");
1074 /* Note: highpri because network receive is latency sensitive */
1075 wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
1076 rpciod_workqueue = wq;
1077 return rpciod_workqueue != NULL;
1078}
1079
1080static void rpciod_stop(void)
1081{
1082 struct workqueue_struct *wq = NULL;
1083
1084 if (rpciod_workqueue == NULL)
1085 return;
1086 dprintk("RPC: destroying workqueue rpciod\n");
1087
1088 wq = rpciod_workqueue;
1089 rpciod_workqueue = NULL;
1090 destroy_workqueue(wq);
1091}
1092
1093void
1094rpc_destroy_mempool(void)
1095{
1096 rpciod_stop();
1097 mempool_destroy(rpc_buffer_mempool);
1098 mempool_destroy(rpc_task_mempool);
1099 kmem_cache_destroy(rpc_task_slabp);
1100 kmem_cache_destroy(rpc_buffer_slabp);
1101 rpc_destroy_wait_queue(&delay_queue);
1102}
1103
1104int
1105rpc_init_mempool(void)
1106{
1107 /*
1108 * The following is not strictly a mempool initialisation,
1109 * but there is no harm in doing it here
1110 */
1111 rpc_init_wait_queue(&delay_queue, "delayq");
1112 if (!rpciod_start())
1113 goto err_nomem;
1114
1115 rpc_task_slabp = kmem_cache_create("rpc_tasks",
1116 sizeof(struct rpc_task),
1117 0, SLAB_HWCACHE_ALIGN,
1118 NULL);
1119 if (!rpc_task_slabp)
1120 goto err_nomem;
1121 rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1122 RPC_BUFFER_MAXSIZE,
1123 0, SLAB_HWCACHE_ALIGN,
1124 NULL);
1125 if (!rpc_buffer_slabp)
1126 goto err_nomem;
1127 rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
1128 rpc_task_slabp);
1129 if (!rpc_task_mempool)
1130 goto err_nomem;
1131 rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
1132 rpc_buffer_slabp);
1133 if (!rpc_buffer_mempool)
1134 goto err_nomem;
1135 return 0;
1136err_nomem:
1137 rpc_destroy_mempool();
1138 return -ENOMEM;
1139}
1/*
2 * linux/net/sunrpc/sched.c
3 *
4 * Scheduling for synchronous and asynchronous RPC requests.
5 *
6 * Copyright (C) 1996 Olaf Kirch, <okir@monad.swb.de>
7 *
8 * TCP NFS related read + write fixes
9 * (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
10 */
11
12#include <linux/module.h>
13
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>
22
23#include <linux/sunrpc/clnt.h>
24
25#include "sunrpc.h"
26
27#ifdef RPC_DEBUG
28#define RPCDBG_FACILITY RPCDBG_SCHED
29#endif
30
31#define CREATE_TRACE_POINTS
32#include <trace/events/sunrpc.h>
33
34/*
35 * RPC slabs and memory pools
36 */
37#define RPC_BUFFER_MAXSIZE (2048)
38#define RPC_BUFFER_POOLSIZE (8)
39#define RPC_TASK_POOLSIZE (8)
40static struct kmem_cache *rpc_task_slabp __read_mostly;
41static struct kmem_cache *rpc_buffer_slabp __read_mostly;
42static mempool_t *rpc_task_mempool __read_mostly;
43static mempool_t *rpc_buffer_mempool __read_mostly;
44
45static void rpc_async_schedule(struct work_struct *);
46static void rpc_release_task(struct rpc_task *task);
47static void __rpc_queue_timer_fn(unsigned long ptr);
48
49/*
50 * RPC tasks sit here while waiting for conditions to improve.
51 */
52static struct rpc_wait_queue delay_queue;
53
54/*
55 * rpciod-related stuff
56 */
57struct workqueue_struct *rpciod_workqueue;
58
59/*
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
62 * rpc_run_timer().
63 */
64static void
65__rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
66{
67 if (task->tk_timeout == 0)
68 return;
69 dprintk("RPC: %5u disabling timer\n", task->tk_pid);
70 task->tk_timeout = 0;
71 list_del(&task->u.tk_wait.timer_list);
72 if (list_empty(&queue->timer_list.list))
73 del_timer(&queue->timer_list.timer);
74}
75
76static void
77rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)
78{
79 queue->timer_list.expires = expires;
80 mod_timer(&queue->timer_list.timer, expires);
81}
82
83/*
84 * Set up a timer for the current task.
85 */
86static void
87__rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
88{
89 if (!task->tk_timeout)
90 return;
91
92 dprintk("RPC: %5u setting alarm for %lu ms\n",
93 task->tk_pid, task->tk_timeout * 1000 / HZ);
94
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);
99}
100
101/*
102 * Add new request to a priority queue.
103 */
104static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue,
105 struct rpc_task *task,
106 unsigned char queue_priority)
107{
108 struct list_head *q;
109 struct rpc_task *t;
110
111 INIT_LIST_HEAD(&task->u.tk_wait.links);
112 q = &queue->tasks[queue_priority];
113 if (unlikely(queue_priority > queue->maxpriority))
114 q = &queue->tasks[queue->maxpriority];
115 list_for_each_entry(t, q, u.tk_wait.list) {
116 if (t->tk_owner == task->tk_owner) {
117 list_add_tail(&task->u.tk_wait.list, &t->u.tk_wait.links);
118 return;
119 }
120 }
121 list_add_tail(&task->u.tk_wait.list, q);
122}
123
124/*
125 * Add new request to wait queue.
126 *
127 * Swapper tasks always get inserted at the head of the queue.
128 * This should avoid many nasty memory deadlocks and hopefully
129 * improve overall performance.
130 * Everyone else gets appended to the queue to ensure proper FIFO behavior.
131 */
132static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
133 struct rpc_task *task,
134 unsigned char queue_priority)
135{
136 BUG_ON (RPC_IS_QUEUED(task));
137
138 if (RPC_IS_PRIORITY(queue))
139 __rpc_add_wait_queue_priority(queue, task, queue_priority);
140 else if (RPC_IS_SWAPPER(task))
141 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
142 else
143 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
144 task->tk_waitqueue = queue;
145 queue->qlen++;
146 rpc_set_queued(task);
147
148 dprintk("RPC: %5u added to queue %p \"%s\"\n",
149 task->tk_pid, queue, rpc_qname(queue));
150}
151
152/*
153 * Remove request from a priority queue.
154 */
155static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
156{
157 struct rpc_task *t;
158
159 if (!list_empty(&task->u.tk_wait.links)) {
160 t = list_entry(task->u.tk_wait.links.next, struct rpc_task, u.tk_wait.list);
161 list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);
162 list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);
163 }
164}
165
166/*
167 * Remove request from queue.
168 * Note: must be called with spin lock held.
169 */
170static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
171{
172 __rpc_disable_timer(queue, task);
173 if (RPC_IS_PRIORITY(queue))
174 __rpc_remove_wait_queue_priority(task);
175 list_del(&task->u.tk_wait.list);
176 queue->qlen--;
177 dprintk("RPC: %5u removed from queue %p \"%s\"\n",
178 task->tk_pid, queue, rpc_qname(queue));
179}
180
181static inline void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
182{
183 queue->priority = priority;
184 queue->count = 1 << (priority * 2);
185}
186
187static inline void rpc_set_waitqueue_owner(struct rpc_wait_queue *queue, pid_t pid)
188{
189 queue->owner = pid;
190 queue->nr = RPC_BATCH_COUNT;
191}
192
193static inline void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
194{
195 rpc_set_waitqueue_priority(queue, queue->maxpriority);
196 rpc_set_waitqueue_owner(queue, 0);
197}
198
199static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
200{
201 int i;
202
203 spin_lock_init(&queue->lock);
204 for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
205 INIT_LIST_HEAD(&queue->tasks[i]);
206 queue->maxpriority = nr_queues - 1;
207 rpc_reset_waitqueue_priority(queue);
208 queue->qlen = 0;
209 setup_timer(&queue->timer_list.timer, __rpc_queue_timer_fn, (unsigned long)queue);
210 INIT_LIST_HEAD(&queue->timer_list.list);
211 rpc_assign_waitqueue_name(queue, qname);
212}
213
214void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
215{
216 __rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY);
217}
218EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue);
219
220void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
221{
222 __rpc_init_priority_wait_queue(queue, qname, 1);
223}
224EXPORT_SYMBOL_GPL(rpc_init_wait_queue);
225
226void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)
227{
228 del_timer_sync(&queue->timer_list.timer);
229}
230EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
231
232static int rpc_wait_bit_killable(void *word)
233{
234 if (fatal_signal_pending(current))
235 return -ERESTARTSYS;
236 freezable_schedule();
237 return 0;
238}
239
240#ifdef RPC_DEBUG
241static void rpc_task_set_debuginfo(struct rpc_task *task)
242{
243 static atomic_t rpc_pid;
244
245 task->tk_pid = atomic_inc_return(&rpc_pid);
246}
247#else
248static inline void rpc_task_set_debuginfo(struct rpc_task *task)
249{
250}
251#endif
252
253static void rpc_set_active(struct rpc_task *task)
254{
255 trace_rpc_task_begin(task->tk_client, task, NULL);
256
257 rpc_task_set_debuginfo(task);
258 set_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
259}
260
261/*
262 * Mark an RPC call as having completed by clearing the 'active' bit
263 * and then waking up all tasks that were sleeping.
264 */
265static int rpc_complete_task(struct rpc_task *task)
266{
267 void *m = &task->tk_runstate;
268 wait_queue_head_t *wq = bit_waitqueue(m, RPC_TASK_ACTIVE);
269 struct wait_bit_key k = __WAIT_BIT_KEY_INITIALIZER(m, RPC_TASK_ACTIVE);
270 unsigned long flags;
271 int ret;
272
273 trace_rpc_task_complete(task->tk_client, task, NULL);
274
275 spin_lock_irqsave(&wq->lock, flags);
276 clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
277 ret = atomic_dec_and_test(&task->tk_count);
278 if (waitqueue_active(wq))
279 __wake_up_locked_key(wq, TASK_NORMAL, &k);
280 spin_unlock_irqrestore(&wq->lock, flags);
281 return ret;
282}
283
284/*
285 * Allow callers to wait for completion of an RPC call
286 *
287 * Note the use of out_of_line_wait_on_bit() rather than wait_on_bit()
288 * to enforce taking of the wq->lock and hence avoid races with
289 * rpc_complete_task().
290 */
291int __rpc_wait_for_completion_task(struct rpc_task *task, int (*action)(void *))
292{
293 if (action == NULL)
294 action = rpc_wait_bit_killable;
295 return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
296 action, TASK_KILLABLE);
297}
298EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
299
300/*
301 * Make an RPC task runnable.
302 *
303 * Note: If the task is ASYNC, this must be called with
304 * the spinlock held to protect the wait queue operation.
305 */
306static void rpc_make_runnable(struct rpc_task *task)
307{
308 rpc_clear_queued(task);
309 if (rpc_test_and_set_running(task))
310 return;
311 if (RPC_IS_ASYNC(task)) {
312 INIT_WORK(&task->u.tk_work, rpc_async_schedule);
313 queue_work(rpciod_workqueue, &task->u.tk_work);
314 } else
315 wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
316}
317
318/*
319 * Prepare for sleeping on a wait queue.
320 * By always appending tasks to the list we ensure FIFO behavior.
321 * NB: An RPC task will only receive interrupt-driven events as long
322 * as it's on a wait queue.
323 */
324static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
325 struct rpc_task *task,
326 rpc_action action,
327 unsigned char queue_priority)
328{
329 dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n",
330 task->tk_pid, rpc_qname(q), jiffies);
331
332 trace_rpc_task_sleep(task->tk_client, task, q);
333
334 __rpc_add_wait_queue(q, task, queue_priority);
335
336 BUG_ON(task->tk_callback != NULL);
337 task->tk_callback = action;
338 __rpc_add_timer(q, task);
339}
340
341void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
342 rpc_action action)
343{
344 /* We shouldn't ever put an inactive task to sleep */
345 BUG_ON(!RPC_IS_ACTIVATED(task));
346
347 /*
348 * Protect the queue operations.
349 */
350 spin_lock_bh(&q->lock);
351 __rpc_sleep_on_priority(q, task, action, task->tk_priority);
352 spin_unlock_bh(&q->lock);
353}
354EXPORT_SYMBOL_GPL(rpc_sleep_on);
355
356void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
357 rpc_action action, int priority)
358{
359 /* We shouldn't ever put an inactive task to sleep */
360 BUG_ON(!RPC_IS_ACTIVATED(task));
361
362 /*
363 * Protect the queue operations.
364 */
365 spin_lock_bh(&q->lock);
366 __rpc_sleep_on_priority(q, task, action, priority - RPC_PRIORITY_LOW);
367 spin_unlock_bh(&q->lock);
368}
369
370/**
371 * __rpc_do_wake_up_task - wake up a single rpc_task
372 * @queue: wait queue
373 * @task: task to be woken up
374 *
375 * Caller must hold queue->lock, and have cleared the task queued flag.
376 */
377static void __rpc_do_wake_up_task(struct rpc_wait_queue *queue, struct rpc_task *task)
378{
379 dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
380 task->tk_pid, jiffies);
381
382 /* Has the task been executed yet? If not, we cannot wake it up! */
383 if (!RPC_IS_ACTIVATED(task)) {
384 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
385 return;
386 }
387
388 trace_rpc_task_wakeup(task->tk_client, task, queue);
389
390 __rpc_remove_wait_queue(queue, task);
391
392 rpc_make_runnable(task);
393
394 dprintk("RPC: __rpc_wake_up_task done\n");
395}
396
397/*
398 * Wake up a queued task while the queue lock is being held
399 */
400static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
401{
402 if (RPC_IS_QUEUED(task) && task->tk_waitqueue == queue)
403 __rpc_do_wake_up_task(queue, task);
404}
405
406/*
407 * Tests whether rpc queue is empty
408 */
409int rpc_queue_empty(struct rpc_wait_queue *queue)
410{
411 int res;
412
413 spin_lock_bh(&queue->lock);
414 res = queue->qlen;
415 spin_unlock_bh(&queue->lock);
416 return res == 0;
417}
418EXPORT_SYMBOL_GPL(rpc_queue_empty);
419
420/*
421 * Wake up a task on a specific queue
422 */
423void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
424{
425 spin_lock_bh(&queue->lock);
426 rpc_wake_up_task_queue_locked(queue, task);
427 spin_unlock_bh(&queue->lock);
428}
429EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
430
431/*
432 * Wake up the next task on a priority queue.
433 */
434static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *queue)
435{
436 struct list_head *q;
437 struct rpc_task *task;
438
439 /*
440 * Service a batch of tasks from a single owner.
441 */
442 q = &queue->tasks[queue->priority];
443 if (!list_empty(q)) {
444 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
445 if (queue->owner == task->tk_owner) {
446 if (--queue->nr)
447 goto out;
448 list_move_tail(&task->u.tk_wait.list, q);
449 }
450 /*
451 * Check if we need to switch queues.
452 */
453 if (--queue->count)
454 goto new_owner;
455 }
456
457 /*
458 * Service the next queue.
459 */
460 do {
461 if (q == &queue->tasks[0])
462 q = &queue->tasks[queue->maxpriority];
463 else
464 q = q - 1;
465 if (!list_empty(q)) {
466 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
467 goto new_queue;
468 }
469 } while (q != &queue->tasks[queue->priority]);
470
471 rpc_reset_waitqueue_priority(queue);
472 return NULL;
473
474new_queue:
475 rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
476new_owner:
477 rpc_set_waitqueue_owner(queue, task->tk_owner);
478out:
479 return task;
480}
481
482static struct rpc_task *__rpc_find_next_queued(struct rpc_wait_queue *queue)
483{
484 if (RPC_IS_PRIORITY(queue))
485 return __rpc_find_next_queued_priority(queue);
486 if (!list_empty(&queue->tasks[0]))
487 return list_first_entry(&queue->tasks[0], struct rpc_task, u.tk_wait.list);
488 return NULL;
489}
490
491/*
492 * Wake up the first task on the wait queue.
493 */
494struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue,
495 bool (*func)(struct rpc_task *, void *), void *data)
496{
497 struct rpc_task *task = NULL;
498
499 dprintk("RPC: wake_up_first(%p \"%s\")\n",
500 queue, rpc_qname(queue));
501 spin_lock_bh(&queue->lock);
502 task = __rpc_find_next_queued(queue);
503 if (task != NULL) {
504 if (func(task, data))
505 rpc_wake_up_task_queue_locked(queue, task);
506 else
507 task = NULL;
508 }
509 spin_unlock_bh(&queue->lock);
510
511 return task;
512}
513EXPORT_SYMBOL_GPL(rpc_wake_up_first);
514
515static bool rpc_wake_up_next_func(struct rpc_task *task, void *data)
516{
517 return true;
518}
519
520/*
521 * Wake up the next task on the wait queue.
522*/
523struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *queue)
524{
525 return rpc_wake_up_first(queue, rpc_wake_up_next_func, NULL);
526}
527EXPORT_SYMBOL_GPL(rpc_wake_up_next);
528
529/**
530 * rpc_wake_up - wake up all rpc_tasks
531 * @queue: rpc_wait_queue on which the tasks are sleeping
532 *
533 * Grabs queue->lock
534 */
535void rpc_wake_up(struct rpc_wait_queue *queue)
536{
537 struct list_head *head;
538
539 spin_lock_bh(&queue->lock);
540 head = &queue->tasks[queue->maxpriority];
541 for (;;) {
542 while (!list_empty(head)) {
543 struct rpc_task *task;
544 task = list_first_entry(head,
545 struct rpc_task,
546 u.tk_wait.list);
547 rpc_wake_up_task_queue_locked(queue, task);
548 }
549 if (head == &queue->tasks[0])
550 break;
551 head--;
552 }
553 spin_unlock_bh(&queue->lock);
554}
555EXPORT_SYMBOL_GPL(rpc_wake_up);
556
557/**
558 * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
559 * @queue: rpc_wait_queue on which the tasks are sleeping
560 * @status: status value to set
561 *
562 * Grabs queue->lock
563 */
564void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
565{
566 struct list_head *head;
567
568 spin_lock_bh(&queue->lock);
569 head = &queue->tasks[queue->maxpriority];
570 for (;;) {
571 while (!list_empty(head)) {
572 struct rpc_task *task;
573 task = list_first_entry(head,
574 struct rpc_task,
575 u.tk_wait.list);
576 task->tk_status = status;
577 rpc_wake_up_task_queue_locked(queue, task);
578 }
579 if (head == &queue->tasks[0])
580 break;
581 head--;
582 }
583 spin_unlock_bh(&queue->lock);
584}
585EXPORT_SYMBOL_GPL(rpc_wake_up_status);
586
587static void __rpc_queue_timer_fn(unsigned long ptr)
588{
589 struct rpc_wait_queue *queue = (struct rpc_wait_queue *)ptr;
590 struct rpc_task *task, *n;
591 unsigned long expires, now, timeo;
592
593 spin_lock(&queue->lock);
594 expires = now = jiffies;
595 list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) {
596 timeo = task->u.tk_wait.expires;
597 if (time_after_eq(now, timeo)) {
598 dprintk("RPC: %5u timeout\n", task->tk_pid);
599 task->tk_status = -ETIMEDOUT;
600 rpc_wake_up_task_queue_locked(queue, task);
601 continue;
602 }
603 if (expires == now || time_after(expires, timeo))
604 expires = timeo;
605 }
606 if (!list_empty(&queue->timer_list.list))
607 rpc_set_queue_timer(queue, expires);
608 spin_unlock(&queue->lock);
609}
610
611static void __rpc_atrun(struct rpc_task *task)
612{
613 task->tk_status = 0;
614}
615
616/*
617 * Run a task at a later time
618 */
619void rpc_delay(struct rpc_task *task, unsigned long delay)
620{
621 task->tk_timeout = delay;
622 rpc_sleep_on(&delay_queue, task, __rpc_atrun);
623}
624EXPORT_SYMBOL_GPL(rpc_delay);
625
626/*
627 * Helper to call task->tk_ops->rpc_call_prepare
628 */
629void rpc_prepare_task(struct rpc_task *task)
630{
631 task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
632}
633
634static void
635rpc_init_task_statistics(struct rpc_task *task)
636{
637 /* Initialize retry counters */
638 task->tk_garb_retry = 2;
639 task->tk_cred_retry = 2;
640 task->tk_rebind_retry = 2;
641
642 /* starting timestamp */
643 task->tk_start = ktime_get();
644}
645
646static void
647rpc_reset_task_statistics(struct rpc_task *task)
648{
649 task->tk_timeouts = 0;
650 task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_KILLED|RPC_TASK_SENT);
651
652 rpc_init_task_statistics(task);
653}
654
655/*
656 * Helper that calls task->tk_ops->rpc_call_done if it exists
657 */
658void rpc_exit_task(struct rpc_task *task)
659{
660 task->tk_action = NULL;
661 if (task->tk_ops->rpc_call_done != NULL) {
662 task->tk_ops->rpc_call_done(task, task->tk_calldata);
663 if (task->tk_action != NULL) {
664 WARN_ON(RPC_ASSASSINATED(task));
665 /* Always release the RPC slot and buffer memory */
666 xprt_release(task);
667 rpc_reset_task_statistics(task);
668 }
669 }
670}
671
672void rpc_exit(struct rpc_task *task, int status)
673{
674 task->tk_status = status;
675 task->tk_action = rpc_exit_task;
676 if (RPC_IS_QUEUED(task))
677 rpc_wake_up_queued_task(task->tk_waitqueue, task);
678}
679EXPORT_SYMBOL_GPL(rpc_exit);
680
681void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
682{
683 if (ops->rpc_release != NULL)
684 ops->rpc_release(calldata);
685}
686
687/*
688 * This is the RPC `scheduler' (or rather, the finite state machine).
689 */
690static void __rpc_execute(struct rpc_task *task)
691{
692 struct rpc_wait_queue *queue;
693 int task_is_async = RPC_IS_ASYNC(task);
694 int status = 0;
695
696 dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
697 task->tk_pid, task->tk_flags);
698
699 BUG_ON(RPC_IS_QUEUED(task));
700
701 for (;;) {
702 void (*do_action)(struct rpc_task *);
703
704 /*
705 * Execute any pending callback first.
706 */
707 do_action = task->tk_callback;
708 task->tk_callback = NULL;
709 if (do_action == NULL) {
710 /*
711 * Perform the next FSM step.
712 * tk_action may be NULL if the task has been killed.
713 * In particular, note that rpc_killall_tasks may
714 * do this at any time, so beware when dereferencing.
715 */
716 do_action = task->tk_action;
717 if (do_action == NULL)
718 break;
719 }
720 trace_rpc_task_run_action(task->tk_client, task, task->tk_action);
721 do_action(task);
722
723 /*
724 * Lockless check for whether task is sleeping or not.
725 */
726 if (!RPC_IS_QUEUED(task))
727 continue;
728 /*
729 * The queue->lock protects against races with
730 * rpc_make_runnable().
731 *
732 * Note that once we clear RPC_TASK_RUNNING on an asynchronous
733 * rpc_task, rpc_make_runnable() can assign it to a
734 * different workqueue. We therefore cannot assume that the
735 * rpc_task pointer may still be dereferenced.
736 */
737 queue = task->tk_waitqueue;
738 spin_lock_bh(&queue->lock);
739 if (!RPC_IS_QUEUED(task)) {
740 spin_unlock_bh(&queue->lock);
741 continue;
742 }
743 rpc_clear_running(task);
744 spin_unlock_bh(&queue->lock);
745 if (task_is_async)
746 return;
747
748 /* sync task: sleep here */
749 dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid);
750 status = out_of_line_wait_on_bit(&task->tk_runstate,
751 RPC_TASK_QUEUED, rpc_wait_bit_killable,
752 TASK_KILLABLE);
753 if (status == -ERESTARTSYS) {
754 /*
755 * When a sync task receives a signal, it exits with
756 * -ERESTARTSYS. In order to catch any callbacks that
757 * clean up after sleeping on some queue, we don't
758 * break the loop here, but go around once more.
759 */
760 dprintk("RPC: %5u got signal\n", task->tk_pid);
761 task->tk_flags |= RPC_TASK_KILLED;
762 rpc_exit(task, -ERESTARTSYS);
763 }
764 rpc_set_running(task);
765 dprintk("RPC: %5u sync task resuming\n", task->tk_pid);
766 }
767
768 dprintk("RPC: %5u return %d, status %d\n", task->tk_pid, status,
769 task->tk_status);
770 /* Release all resources associated with the task */
771 rpc_release_task(task);
772}
773
774/*
775 * User-visible entry point to the scheduler.
776 *
777 * This may be called recursively if e.g. an async NFS task updates
778 * the attributes and finds that dirty pages must be flushed.
779 * NOTE: Upon exit of this function the task is guaranteed to be
780 * released. In particular note that tk_release() will have
781 * been called, so your task memory may have been freed.
782 */
783void rpc_execute(struct rpc_task *task)
784{
785 rpc_set_active(task);
786 rpc_make_runnable(task);
787 if (!RPC_IS_ASYNC(task))
788 __rpc_execute(task);
789}
790
791static void rpc_async_schedule(struct work_struct *work)
792{
793 current->flags |= PF_FSTRANS;
794 __rpc_execute(container_of(work, struct rpc_task, u.tk_work));
795 current->flags &= ~PF_FSTRANS;
796}
797
798/**
799 * rpc_malloc - allocate an RPC buffer
800 * @task: RPC task that will use this buffer
801 * @size: requested byte size
802 *
803 * To prevent rpciod from hanging, this allocator never sleeps,
804 * returning NULL if the request cannot be serviced immediately.
805 * The caller can arrange to sleep in a way that is safe for rpciod.
806 *
807 * Most requests are 'small' (under 2KiB) and can be serviced from a
808 * mempool, ensuring that NFS reads and writes can always proceed,
809 * and that there is good locality of reference for these buffers.
810 *
811 * In order to avoid memory starvation triggering more writebacks of
812 * NFS requests, we avoid using GFP_KERNEL.
813 */
814void *rpc_malloc(struct rpc_task *task, size_t size)
815{
816 struct rpc_buffer *buf;
817 gfp_t gfp = RPC_IS_SWAPPER(task) ? GFP_ATOMIC : GFP_NOWAIT;
818
819 size += sizeof(struct rpc_buffer);
820 if (size <= RPC_BUFFER_MAXSIZE)
821 buf = mempool_alloc(rpc_buffer_mempool, gfp);
822 else
823 buf = kmalloc(size, gfp);
824
825 if (!buf)
826 return NULL;
827
828 buf->len = size;
829 dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
830 task->tk_pid, size, buf);
831 return &buf->data;
832}
833EXPORT_SYMBOL_GPL(rpc_malloc);
834
835/**
836 * rpc_free - free buffer allocated via rpc_malloc
837 * @buffer: buffer to free
838 *
839 */
840void rpc_free(void *buffer)
841{
842 size_t size;
843 struct rpc_buffer *buf;
844
845 if (!buffer)
846 return;
847
848 buf = container_of(buffer, struct rpc_buffer, data);
849 size = buf->len;
850
851 dprintk("RPC: freeing buffer of size %zu at %p\n",
852 size, buf);
853
854 if (size <= RPC_BUFFER_MAXSIZE)
855 mempool_free(buf, rpc_buffer_mempool);
856 else
857 kfree(buf);
858}
859EXPORT_SYMBOL_GPL(rpc_free);
860
861/*
862 * Creation and deletion of RPC task structures
863 */
864static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *task_setup_data)
865{
866 memset(task, 0, sizeof(*task));
867 atomic_set(&task->tk_count, 1);
868 task->tk_flags = task_setup_data->flags;
869 task->tk_ops = task_setup_data->callback_ops;
870 task->tk_calldata = task_setup_data->callback_data;
871 INIT_LIST_HEAD(&task->tk_task);
872
873 task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW;
874 task->tk_owner = current->tgid;
875
876 /* Initialize workqueue for async tasks */
877 task->tk_workqueue = task_setup_data->workqueue;
878
879 if (task->tk_ops->rpc_call_prepare != NULL)
880 task->tk_action = rpc_prepare_task;
881
882 rpc_init_task_statistics(task);
883
884 dprintk("RPC: new task initialized, procpid %u\n",
885 task_pid_nr(current));
886}
887
888static struct rpc_task *
889rpc_alloc_task(void)
890{
891 return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
892}
893
894/*
895 * Create a new task for the specified client.
896 */
897struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
898{
899 struct rpc_task *task = setup_data->task;
900 unsigned short flags = 0;
901
902 if (task == NULL) {
903 task = rpc_alloc_task();
904 if (task == NULL) {
905 rpc_release_calldata(setup_data->callback_ops,
906 setup_data->callback_data);
907 return ERR_PTR(-ENOMEM);
908 }
909 flags = RPC_TASK_DYNAMIC;
910 }
911
912 rpc_init_task(task, setup_data);
913 task->tk_flags |= flags;
914 dprintk("RPC: allocated task %p\n", task);
915 return task;
916}
917
918static void rpc_free_task(struct rpc_task *task)
919{
920 const struct rpc_call_ops *tk_ops = task->tk_ops;
921 void *calldata = task->tk_calldata;
922
923 if (task->tk_flags & RPC_TASK_DYNAMIC) {
924 dprintk("RPC: %5u freeing task\n", task->tk_pid);
925 mempool_free(task, rpc_task_mempool);
926 }
927 rpc_release_calldata(tk_ops, calldata);
928}
929
930static void rpc_async_release(struct work_struct *work)
931{
932 rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
933}
934
935static void rpc_release_resources_task(struct rpc_task *task)
936{
937 if (task->tk_rqstp)
938 xprt_release(task);
939 if (task->tk_msg.rpc_cred) {
940 put_rpccred(task->tk_msg.rpc_cred);
941 task->tk_msg.rpc_cred = NULL;
942 }
943 rpc_task_release_client(task);
944}
945
946static void rpc_final_put_task(struct rpc_task *task,
947 struct workqueue_struct *q)
948{
949 if (q != NULL) {
950 INIT_WORK(&task->u.tk_work, rpc_async_release);
951 queue_work(q, &task->u.tk_work);
952 } else
953 rpc_free_task(task);
954}
955
956static void rpc_do_put_task(struct rpc_task *task, struct workqueue_struct *q)
957{
958 if (atomic_dec_and_test(&task->tk_count)) {
959 rpc_release_resources_task(task);
960 rpc_final_put_task(task, q);
961 }
962}
963
964void rpc_put_task(struct rpc_task *task)
965{
966 rpc_do_put_task(task, NULL);
967}
968EXPORT_SYMBOL_GPL(rpc_put_task);
969
970void rpc_put_task_async(struct rpc_task *task)
971{
972 rpc_do_put_task(task, task->tk_workqueue);
973}
974EXPORT_SYMBOL_GPL(rpc_put_task_async);
975
976static void rpc_release_task(struct rpc_task *task)
977{
978 dprintk("RPC: %5u release task\n", task->tk_pid);
979
980 BUG_ON (RPC_IS_QUEUED(task));
981
982 rpc_release_resources_task(task);
983
984 /*
985 * Note: at this point we have been removed from rpc_clnt->cl_tasks,
986 * so it should be safe to use task->tk_count as a test for whether
987 * or not any other processes still hold references to our rpc_task.
988 */
989 if (atomic_read(&task->tk_count) != 1 + !RPC_IS_ASYNC(task)) {
990 /* Wake up anyone who may be waiting for task completion */
991 if (!rpc_complete_task(task))
992 return;
993 } else {
994 if (!atomic_dec_and_test(&task->tk_count))
995 return;
996 }
997 rpc_final_put_task(task, task->tk_workqueue);
998}
999
1000int rpciod_up(void)
1001{
1002 return try_module_get(THIS_MODULE) ? 0 : -EINVAL;
1003}
1004
1005void rpciod_down(void)
1006{
1007 module_put(THIS_MODULE);
1008}
1009
1010/*
1011 * Start up the rpciod workqueue.
1012 */
1013static int rpciod_start(void)
1014{
1015 struct workqueue_struct *wq;
1016
1017 /*
1018 * Create the rpciod thread and wait for it to start.
1019 */
1020 dprintk("RPC: creating workqueue rpciod\n");
1021 wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM, 0);
1022 rpciod_workqueue = wq;
1023 return rpciod_workqueue != NULL;
1024}
1025
1026static void rpciod_stop(void)
1027{
1028 struct workqueue_struct *wq = NULL;
1029
1030 if (rpciod_workqueue == NULL)
1031 return;
1032 dprintk("RPC: destroying workqueue rpciod\n");
1033
1034 wq = rpciod_workqueue;
1035 rpciod_workqueue = NULL;
1036 destroy_workqueue(wq);
1037}
1038
1039void
1040rpc_destroy_mempool(void)
1041{
1042 rpciod_stop();
1043 if (rpc_buffer_mempool)
1044 mempool_destroy(rpc_buffer_mempool);
1045 if (rpc_task_mempool)
1046 mempool_destroy(rpc_task_mempool);
1047 if (rpc_task_slabp)
1048 kmem_cache_destroy(rpc_task_slabp);
1049 if (rpc_buffer_slabp)
1050 kmem_cache_destroy(rpc_buffer_slabp);
1051 rpc_destroy_wait_queue(&delay_queue);
1052}
1053
1054int
1055rpc_init_mempool(void)
1056{
1057 /*
1058 * The following is not strictly a mempool initialisation,
1059 * but there is no harm in doing it here
1060 */
1061 rpc_init_wait_queue(&delay_queue, "delayq");
1062 if (!rpciod_start())
1063 goto err_nomem;
1064
1065 rpc_task_slabp = kmem_cache_create("rpc_tasks",
1066 sizeof(struct rpc_task),
1067 0, SLAB_HWCACHE_ALIGN,
1068 NULL);
1069 if (!rpc_task_slabp)
1070 goto err_nomem;
1071 rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1072 RPC_BUFFER_MAXSIZE,
1073 0, SLAB_HWCACHE_ALIGN,
1074 NULL);
1075 if (!rpc_buffer_slabp)
1076 goto err_nomem;
1077 rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
1078 rpc_task_slabp);
1079 if (!rpc_task_mempool)
1080 goto err_nomem;
1081 rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
1082 rpc_buffer_slabp);
1083 if (!rpc_buffer_mempool)
1084 goto err_nomem;
1085 return 0;
1086err_nomem:
1087 rpc_destroy_mempool();
1088 return -ENOMEM;
1089}