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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
22#include <linux/sunrpc/clnt.h>
23
24#include "sunrpc.h"
25
26#ifdef RPC_DEBUG
27#define RPCDBG_FACILITY RPCDBG_SCHED
28#endif
29
30/*
31 * RPC slabs and memory pools
32 */
33#define RPC_BUFFER_MAXSIZE (2048)
34#define RPC_BUFFER_POOLSIZE (8)
35#define RPC_TASK_POOLSIZE (8)
36static struct kmem_cache *rpc_task_slabp __read_mostly;
37static struct kmem_cache *rpc_buffer_slabp __read_mostly;
38static mempool_t *rpc_task_mempool __read_mostly;
39static mempool_t *rpc_buffer_mempool __read_mostly;
40
41static void rpc_async_schedule(struct work_struct *);
42static void rpc_release_task(struct rpc_task *task);
43static void __rpc_queue_timer_fn(unsigned long ptr);
44
45/*
46 * RPC tasks sit here while waiting for conditions to improve.
47 */
48static struct rpc_wait_queue delay_queue;
49
50/*
51 * rpciod-related stuff
52 */
53struct workqueue_struct *rpciod_workqueue;
54
55/*
56 * Disable the timer for a given RPC task. Should be called with
57 * queue->lock and bh_disabled in order to avoid races within
58 * rpc_run_timer().
59 */
60static void
61__rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
62{
63 if (task->tk_timeout == 0)
64 return;
65 dprintk("RPC: %5u disabling timer\n", task->tk_pid);
66 task->tk_timeout = 0;
67 list_del(&task->u.tk_wait.timer_list);
68 if (list_empty(&queue->timer_list.list))
69 del_timer(&queue->timer_list.timer);
70}
71
72static void
73rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)
74{
75 queue->timer_list.expires = expires;
76 mod_timer(&queue->timer_list.timer, expires);
77}
78
79/*
80 * Set up a timer for the current task.
81 */
82static void
83__rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
84{
85 if (!task->tk_timeout)
86 return;
87
88 dprintk("RPC: %5u setting alarm for %lu ms\n",
89 task->tk_pid, task->tk_timeout * 1000 / HZ);
90
91 task->u.tk_wait.expires = jiffies + task->tk_timeout;
92 if (list_empty(&queue->timer_list.list) || time_before(task->u.tk_wait.expires, queue->timer_list.expires))
93 rpc_set_queue_timer(queue, task->u.tk_wait.expires);
94 list_add(&task->u.tk_wait.timer_list, &queue->timer_list.list);
95}
96
97/*
98 * Add new request to a priority queue.
99 */
100static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue,
101 struct rpc_task *task,
102 unsigned char queue_priority)
103{
104 struct list_head *q;
105 struct rpc_task *t;
106
107 INIT_LIST_HEAD(&task->u.tk_wait.links);
108 q = &queue->tasks[queue_priority];
109 if (unlikely(queue_priority > queue->maxpriority))
110 q = &queue->tasks[queue->maxpriority];
111 list_for_each_entry(t, q, u.tk_wait.list) {
112 if (t->tk_owner == task->tk_owner) {
113 list_add_tail(&task->u.tk_wait.list, &t->u.tk_wait.links);
114 return;
115 }
116 }
117 list_add_tail(&task->u.tk_wait.list, q);
118}
119
120/*
121 * Add new request to wait queue.
122 *
123 * Swapper tasks always get inserted at the head of the queue.
124 * This should avoid many nasty memory deadlocks and hopefully
125 * improve overall performance.
126 * Everyone else gets appended to the queue to ensure proper FIFO behavior.
127 */
128static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
129 struct rpc_task *task,
130 unsigned char queue_priority)
131{
132 BUG_ON (RPC_IS_QUEUED(task));
133
134 if (RPC_IS_PRIORITY(queue))
135 __rpc_add_wait_queue_priority(queue, task, queue_priority);
136 else if (RPC_IS_SWAPPER(task))
137 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
138 else
139 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
140 task->tk_waitqueue = queue;
141 queue->qlen++;
142 rpc_set_queued(task);
143
144 dprintk("RPC: %5u added to queue %p \"%s\"\n",
145 task->tk_pid, queue, rpc_qname(queue));
146}
147
148/*
149 * Remove request from a priority queue.
150 */
151static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
152{
153 struct rpc_task *t;
154
155 if (!list_empty(&task->u.tk_wait.links)) {
156 t = list_entry(task->u.tk_wait.links.next, struct rpc_task, u.tk_wait.list);
157 list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);
158 list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);
159 }
160}
161
162/*
163 * Remove request from queue.
164 * Note: must be called with spin lock held.
165 */
166static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
167{
168 __rpc_disable_timer(queue, task);
169 if (RPC_IS_PRIORITY(queue))
170 __rpc_remove_wait_queue_priority(task);
171 list_del(&task->u.tk_wait.list);
172 queue->qlen--;
173 dprintk("RPC: %5u removed from queue %p \"%s\"\n",
174 task->tk_pid, queue, rpc_qname(queue));
175}
176
177static inline void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
178{
179 queue->priority = priority;
180 queue->count = 1 << (priority * 2);
181}
182
183static inline void rpc_set_waitqueue_owner(struct rpc_wait_queue *queue, pid_t pid)
184{
185 queue->owner = pid;
186 queue->nr = RPC_BATCH_COUNT;
187}
188
189static inline void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
190{
191 rpc_set_waitqueue_priority(queue, queue->maxpriority);
192 rpc_set_waitqueue_owner(queue, 0);
193}
194
195static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
196{
197 int i;
198
199 spin_lock_init(&queue->lock);
200 for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
201 INIT_LIST_HEAD(&queue->tasks[i]);
202 queue->maxpriority = nr_queues - 1;
203 rpc_reset_waitqueue_priority(queue);
204 queue->qlen = 0;
205 setup_timer(&queue->timer_list.timer, __rpc_queue_timer_fn, (unsigned long)queue);
206 INIT_LIST_HEAD(&queue->timer_list.list);
207#ifdef RPC_DEBUG
208 queue->name = qname;
209#endif
210}
211
212void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
213{
214 __rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY);
215}
216EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue);
217
218void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
219{
220 __rpc_init_priority_wait_queue(queue, qname, 1);
221}
222EXPORT_SYMBOL_GPL(rpc_init_wait_queue);
223
224void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)
225{
226 del_timer_sync(&queue->timer_list.timer);
227}
228EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
229
230static int rpc_wait_bit_killable(void *word)
231{
232 if (fatal_signal_pending(current))
233 return -ERESTARTSYS;
234 schedule();
235 return 0;
236}
237
238#ifdef RPC_DEBUG
239static void rpc_task_set_debuginfo(struct rpc_task *task)
240{
241 static atomic_t rpc_pid;
242
243 task->tk_pid = atomic_inc_return(&rpc_pid);
244}
245#else
246static inline void rpc_task_set_debuginfo(struct rpc_task *task)
247{
248}
249#endif
250
251static void rpc_set_active(struct rpc_task *task)
252{
253 rpc_task_set_debuginfo(task);
254 set_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
255}
256
257/*
258 * Mark an RPC call as having completed by clearing the 'active' bit
259 * and then waking up all tasks that were sleeping.
260 */
261static int rpc_complete_task(struct rpc_task *task)
262{
263 void *m = &task->tk_runstate;
264 wait_queue_head_t *wq = bit_waitqueue(m, RPC_TASK_ACTIVE);
265 struct wait_bit_key k = __WAIT_BIT_KEY_INITIALIZER(m, RPC_TASK_ACTIVE);
266 unsigned long flags;
267 int ret;
268
269 spin_lock_irqsave(&wq->lock, flags);
270 clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
271 ret = atomic_dec_and_test(&task->tk_count);
272 if (waitqueue_active(wq))
273 __wake_up_locked_key(wq, TASK_NORMAL, &k);
274 spin_unlock_irqrestore(&wq->lock, flags);
275 return ret;
276}
277
278/*
279 * Allow callers to wait for completion of an RPC call
280 *
281 * Note the use of out_of_line_wait_on_bit() rather than wait_on_bit()
282 * to enforce taking of the wq->lock and hence avoid races with
283 * rpc_complete_task().
284 */
285int __rpc_wait_for_completion_task(struct rpc_task *task, int (*action)(void *))
286{
287 if (action == NULL)
288 action = rpc_wait_bit_killable;
289 return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
290 action, TASK_KILLABLE);
291}
292EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
293
294/*
295 * Make an RPC task runnable.
296 *
297 * Note: If the task is ASYNC, this must be called with
298 * the spinlock held to protect the wait queue operation.
299 */
300static void rpc_make_runnable(struct rpc_task *task)
301{
302 rpc_clear_queued(task);
303 if (rpc_test_and_set_running(task))
304 return;
305 if (RPC_IS_ASYNC(task)) {
306 INIT_WORK(&task->u.tk_work, rpc_async_schedule);
307 queue_work(rpciod_workqueue, &task->u.tk_work);
308 } else
309 wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
310}
311
312/*
313 * Prepare for sleeping on a wait queue.
314 * By always appending tasks to the list we ensure FIFO behavior.
315 * NB: An RPC task will only receive interrupt-driven events as long
316 * as it's on a wait queue.
317 */
318static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
319 struct rpc_task *task,
320 rpc_action action,
321 unsigned char queue_priority)
322{
323 dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n",
324 task->tk_pid, rpc_qname(q), jiffies);
325
326 __rpc_add_wait_queue(q, task, queue_priority);
327
328 BUG_ON(task->tk_callback != NULL);
329 task->tk_callback = action;
330 __rpc_add_timer(q, task);
331}
332
333void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
334 rpc_action action)
335{
336 /* We shouldn't ever put an inactive task to sleep */
337 BUG_ON(!RPC_IS_ACTIVATED(task));
338
339 /*
340 * Protect the queue operations.
341 */
342 spin_lock_bh(&q->lock);
343 __rpc_sleep_on_priority(q, task, action, task->tk_priority);
344 spin_unlock_bh(&q->lock);
345}
346EXPORT_SYMBOL_GPL(rpc_sleep_on);
347
348void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
349 rpc_action action, int priority)
350{
351 /* We shouldn't ever put an inactive task to sleep */
352 BUG_ON(!RPC_IS_ACTIVATED(task));
353
354 /*
355 * Protect the queue operations.
356 */
357 spin_lock_bh(&q->lock);
358 __rpc_sleep_on_priority(q, task, action, priority - RPC_PRIORITY_LOW);
359 spin_unlock_bh(&q->lock);
360}
361
362/**
363 * __rpc_do_wake_up_task - wake up a single rpc_task
364 * @queue: wait queue
365 * @task: task to be woken up
366 *
367 * Caller must hold queue->lock, and have cleared the task queued flag.
368 */
369static void __rpc_do_wake_up_task(struct rpc_wait_queue *queue, struct rpc_task *task)
370{
371 dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
372 task->tk_pid, jiffies);
373
374 /* Has the task been executed yet? If not, we cannot wake it up! */
375 if (!RPC_IS_ACTIVATED(task)) {
376 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
377 return;
378 }
379
380 __rpc_remove_wait_queue(queue, task);
381
382 rpc_make_runnable(task);
383
384 dprintk("RPC: __rpc_wake_up_task done\n");
385}
386
387/*
388 * Wake up a queued task while the queue lock is being held
389 */
390static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
391{
392 if (RPC_IS_QUEUED(task) && task->tk_waitqueue == queue)
393 __rpc_do_wake_up_task(queue, task);
394}
395
396/*
397 * Tests whether rpc queue is empty
398 */
399int rpc_queue_empty(struct rpc_wait_queue *queue)
400{
401 int res;
402
403 spin_lock_bh(&queue->lock);
404 res = queue->qlen;
405 spin_unlock_bh(&queue->lock);
406 return res == 0;
407}
408EXPORT_SYMBOL_GPL(rpc_queue_empty);
409
410/*
411 * Wake up a task on a specific queue
412 */
413void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
414{
415 spin_lock_bh(&queue->lock);
416 rpc_wake_up_task_queue_locked(queue, task);
417 spin_unlock_bh(&queue->lock);
418}
419EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
420
421/*
422 * Wake up the next task on a priority queue.
423 */
424static struct rpc_task * __rpc_wake_up_next_priority(struct rpc_wait_queue *queue)
425{
426 struct list_head *q;
427 struct rpc_task *task;
428
429 /*
430 * Service a batch of tasks from a single owner.
431 */
432 q = &queue->tasks[queue->priority];
433 if (!list_empty(q)) {
434 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
435 if (queue->owner == task->tk_owner) {
436 if (--queue->nr)
437 goto out;
438 list_move_tail(&task->u.tk_wait.list, q);
439 }
440 /*
441 * Check if we need to switch queues.
442 */
443 if (--queue->count)
444 goto new_owner;
445 }
446
447 /*
448 * Service the next queue.
449 */
450 do {
451 if (q == &queue->tasks[0])
452 q = &queue->tasks[queue->maxpriority];
453 else
454 q = q - 1;
455 if (!list_empty(q)) {
456 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
457 goto new_queue;
458 }
459 } while (q != &queue->tasks[queue->priority]);
460
461 rpc_reset_waitqueue_priority(queue);
462 return NULL;
463
464new_queue:
465 rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
466new_owner:
467 rpc_set_waitqueue_owner(queue, task->tk_owner);
468out:
469 rpc_wake_up_task_queue_locked(queue, task);
470 return task;
471}
472
473/*
474 * Wake up the next task on the wait queue.
475 */
476struct rpc_task * rpc_wake_up_next(struct rpc_wait_queue *queue)
477{
478 struct rpc_task *task = NULL;
479
480 dprintk("RPC: wake_up_next(%p \"%s\")\n",
481 queue, rpc_qname(queue));
482 spin_lock_bh(&queue->lock);
483 if (RPC_IS_PRIORITY(queue))
484 task = __rpc_wake_up_next_priority(queue);
485 else {
486 task_for_first(task, &queue->tasks[0])
487 rpc_wake_up_task_queue_locked(queue, task);
488 }
489 spin_unlock_bh(&queue->lock);
490
491 return task;
492}
493EXPORT_SYMBOL_GPL(rpc_wake_up_next);
494
495/**
496 * rpc_wake_up - wake up all rpc_tasks
497 * @queue: rpc_wait_queue on which the tasks are sleeping
498 *
499 * Grabs queue->lock
500 */
501void rpc_wake_up(struct rpc_wait_queue *queue)
502{
503 struct rpc_task *task, *next;
504 struct list_head *head;
505
506 spin_lock_bh(&queue->lock);
507 head = &queue->tasks[queue->maxpriority];
508 for (;;) {
509 list_for_each_entry_safe(task, next, head, u.tk_wait.list)
510 rpc_wake_up_task_queue_locked(queue, task);
511 if (head == &queue->tasks[0])
512 break;
513 head--;
514 }
515 spin_unlock_bh(&queue->lock);
516}
517EXPORT_SYMBOL_GPL(rpc_wake_up);
518
519/**
520 * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
521 * @queue: rpc_wait_queue on which the tasks are sleeping
522 * @status: status value to set
523 *
524 * Grabs queue->lock
525 */
526void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
527{
528 struct rpc_task *task, *next;
529 struct list_head *head;
530
531 spin_lock_bh(&queue->lock);
532 head = &queue->tasks[queue->maxpriority];
533 for (;;) {
534 list_for_each_entry_safe(task, next, head, u.tk_wait.list) {
535 task->tk_status = status;
536 rpc_wake_up_task_queue_locked(queue, task);
537 }
538 if (head == &queue->tasks[0])
539 break;
540 head--;
541 }
542 spin_unlock_bh(&queue->lock);
543}
544EXPORT_SYMBOL_GPL(rpc_wake_up_status);
545
546static void __rpc_queue_timer_fn(unsigned long ptr)
547{
548 struct rpc_wait_queue *queue = (struct rpc_wait_queue *)ptr;
549 struct rpc_task *task, *n;
550 unsigned long expires, now, timeo;
551
552 spin_lock(&queue->lock);
553 expires = now = jiffies;
554 list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) {
555 timeo = task->u.tk_wait.expires;
556 if (time_after_eq(now, timeo)) {
557 dprintk("RPC: %5u timeout\n", task->tk_pid);
558 task->tk_status = -ETIMEDOUT;
559 rpc_wake_up_task_queue_locked(queue, task);
560 continue;
561 }
562 if (expires == now || time_after(expires, timeo))
563 expires = timeo;
564 }
565 if (!list_empty(&queue->timer_list.list))
566 rpc_set_queue_timer(queue, expires);
567 spin_unlock(&queue->lock);
568}
569
570static void __rpc_atrun(struct rpc_task *task)
571{
572 task->tk_status = 0;
573}
574
575/*
576 * Run a task at a later time
577 */
578void rpc_delay(struct rpc_task *task, unsigned long delay)
579{
580 task->tk_timeout = delay;
581 rpc_sleep_on(&delay_queue, task, __rpc_atrun);
582}
583EXPORT_SYMBOL_GPL(rpc_delay);
584
585/*
586 * Helper to call task->tk_ops->rpc_call_prepare
587 */
588void rpc_prepare_task(struct rpc_task *task)
589{
590 task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
591}
592
593/*
594 * Helper that calls task->tk_ops->rpc_call_done if it exists
595 */
596void rpc_exit_task(struct rpc_task *task)
597{
598 task->tk_action = NULL;
599 if (task->tk_ops->rpc_call_done != NULL) {
600 task->tk_ops->rpc_call_done(task, task->tk_calldata);
601 if (task->tk_action != NULL) {
602 WARN_ON(RPC_ASSASSINATED(task));
603 /* Always release the RPC slot and buffer memory */
604 xprt_release(task);
605 }
606 }
607}
608
609void rpc_exit(struct rpc_task *task, int status)
610{
611 task->tk_status = status;
612 task->tk_action = rpc_exit_task;
613 if (RPC_IS_QUEUED(task))
614 rpc_wake_up_queued_task(task->tk_waitqueue, task);
615}
616EXPORT_SYMBOL_GPL(rpc_exit);
617
618void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
619{
620 if (ops->rpc_release != NULL)
621 ops->rpc_release(calldata);
622}
623
624/*
625 * This is the RPC `scheduler' (or rather, the finite state machine).
626 */
627static void __rpc_execute(struct rpc_task *task)
628{
629 struct rpc_wait_queue *queue;
630 int task_is_async = RPC_IS_ASYNC(task);
631 int status = 0;
632
633 dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
634 task->tk_pid, task->tk_flags);
635
636 BUG_ON(RPC_IS_QUEUED(task));
637
638 for (;;) {
639 void (*do_action)(struct rpc_task *);
640
641 /*
642 * Execute any pending callback first.
643 */
644 do_action = task->tk_callback;
645 task->tk_callback = NULL;
646 if (do_action == NULL) {
647 /*
648 * Perform the next FSM step.
649 * tk_action may be NULL if the task has been killed.
650 * In particular, note that rpc_killall_tasks may
651 * do this at any time, so beware when dereferencing.
652 */
653 do_action = task->tk_action;
654 if (do_action == NULL)
655 break;
656 }
657 do_action(task);
658
659 /*
660 * Lockless check for whether task is sleeping or not.
661 */
662 if (!RPC_IS_QUEUED(task))
663 continue;
664 /*
665 * The queue->lock protects against races with
666 * rpc_make_runnable().
667 *
668 * Note that once we clear RPC_TASK_RUNNING on an asynchronous
669 * rpc_task, rpc_make_runnable() can assign it to a
670 * different workqueue. We therefore cannot assume that the
671 * rpc_task pointer may still be dereferenced.
672 */
673 queue = task->tk_waitqueue;
674 spin_lock_bh(&queue->lock);
675 if (!RPC_IS_QUEUED(task)) {
676 spin_unlock_bh(&queue->lock);
677 continue;
678 }
679 rpc_clear_running(task);
680 spin_unlock_bh(&queue->lock);
681 if (task_is_async)
682 return;
683
684 /* sync task: sleep here */
685 dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid);
686 status = out_of_line_wait_on_bit(&task->tk_runstate,
687 RPC_TASK_QUEUED, rpc_wait_bit_killable,
688 TASK_KILLABLE);
689 if (status == -ERESTARTSYS) {
690 /*
691 * When a sync task receives a signal, it exits with
692 * -ERESTARTSYS. In order to catch any callbacks that
693 * clean up after sleeping on some queue, we don't
694 * break the loop here, but go around once more.
695 */
696 dprintk("RPC: %5u got signal\n", task->tk_pid);
697 task->tk_flags |= RPC_TASK_KILLED;
698 rpc_exit(task, -ERESTARTSYS);
699 }
700 rpc_set_running(task);
701 dprintk("RPC: %5u sync task resuming\n", task->tk_pid);
702 }
703
704 dprintk("RPC: %5u return %d, status %d\n", task->tk_pid, status,
705 task->tk_status);
706 /* Release all resources associated with the task */
707 rpc_release_task(task);
708}
709
710/*
711 * User-visible entry point to the scheduler.
712 *
713 * This may be called recursively if e.g. an async NFS task updates
714 * the attributes and finds that dirty pages must be flushed.
715 * NOTE: Upon exit of this function the task is guaranteed to be
716 * released. In particular note that tk_release() will have
717 * been called, so your task memory may have been freed.
718 */
719void rpc_execute(struct rpc_task *task)
720{
721 rpc_set_active(task);
722 rpc_make_runnable(task);
723 if (!RPC_IS_ASYNC(task))
724 __rpc_execute(task);
725}
726
727static void rpc_async_schedule(struct work_struct *work)
728{
729 __rpc_execute(container_of(work, struct rpc_task, u.tk_work));
730}
731
732/**
733 * rpc_malloc - allocate an RPC buffer
734 * @task: RPC task that will use this buffer
735 * @size: requested byte size
736 *
737 * To prevent rpciod from hanging, this allocator never sleeps,
738 * returning NULL if the request cannot be serviced immediately.
739 * The caller can arrange to sleep in a way that is safe for rpciod.
740 *
741 * Most requests are 'small' (under 2KiB) and can be serviced from a
742 * mempool, ensuring that NFS reads and writes can always proceed,
743 * and that there is good locality of reference for these buffers.
744 *
745 * In order to avoid memory starvation triggering more writebacks of
746 * NFS requests, we avoid using GFP_KERNEL.
747 */
748void *rpc_malloc(struct rpc_task *task, size_t size)
749{
750 struct rpc_buffer *buf;
751 gfp_t gfp = RPC_IS_SWAPPER(task) ? GFP_ATOMIC : GFP_NOWAIT;
752
753 size += sizeof(struct rpc_buffer);
754 if (size <= RPC_BUFFER_MAXSIZE)
755 buf = mempool_alloc(rpc_buffer_mempool, gfp);
756 else
757 buf = kmalloc(size, gfp);
758
759 if (!buf)
760 return NULL;
761
762 buf->len = size;
763 dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
764 task->tk_pid, size, buf);
765 return &buf->data;
766}
767EXPORT_SYMBOL_GPL(rpc_malloc);
768
769/**
770 * rpc_free - free buffer allocated via rpc_malloc
771 * @buffer: buffer to free
772 *
773 */
774void rpc_free(void *buffer)
775{
776 size_t size;
777 struct rpc_buffer *buf;
778
779 if (!buffer)
780 return;
781
782 buf = container_of(buffer, struct rpc_buffer, data);
783 size = buf->len;
784
785 dprintk("RPC: freeing buffer of size %zu at %p\n",
786 size, buf);
787
788 if (size <= RPC_BUFFER_MAXSIZE)
789 mempool_free(buf, rpc_buffer_mempool);
790 else
791 kfree(buf);
792}
793EXPORT_SYMBOL_GPL(rpc_free);
794
795/*
796 * Creation and deletion of RPC task structures
797 */
798static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *task_setup_data)
799{
800 memset(task, 0, sizeof(*task));
801 atomic_set(&task->tk_count, 1);
802 task->tk_flags = task_setup_data->flags;
803 task->tk_ops = task_setup_data->callback_ops;
804 task->tk_calldata = task_setup_data->callback_data;
805 INIT_LIST_HEAD(&task->tk_task);
806
807 /* Initialize retry counters */
808 task->tk_garb_retry = 2;
809 task->tk_cred_retry = 2;
810 task->tk_rebind_retry = 2;
811
812 task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW;
813 task->tk_owner = current->tgid;
814
815 /* Initialize workqueue for async tasks */
816 task->tk_workqueue = task_setup_data->workqueue;
817
818 if (task->tk_ops->rpc_call_prepare != NULL)
819 task->tk_action = rpc_prepare_task;
820
821 /* starting timestamp */
822 task->tk_start = ktime_get();
823
824 dprintk("RPC: new task initialized, procpid %u\n",
825 task_pid_nr(current));
826}
827
828static struct rpc_task *
829rpc_alloc_task(void)
830{
831 return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
832}
833
834/*
835 * Create a new task for the specified client.
836 */
837struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
838{
839 struct rpc_task *task = setup_data->task;
840 unsigned short flags = 0;
841
842 if (task == NULL) {
843 task = rpc_alloc_task();
844 if (task == NULL) {
845 rpc_release_calldata(setup_data->callback_ops,
846 setup_data->callback_data);
847 return ERR_PTR(-ENOMEM);
848 }
849 flags = RPC_TASK_DYNAMIC;
850 }
851
852 rpc_init_task(task, setup_data);
853 task->tk_flags |= flags;
854 dprintk("RPC: allocated task %p\n", task);
855 return task;
856}
857
858static void rpc_free_task(struct rpc_task *task)
859{
860 const struct rpc_call_ops *tk_ops = task->tk_ops;
861 void *calldata = task->tk_calldata;
862
863 if (task->tk_flags & RPC_TASK_DYNAMIC) {
864 dprintk("RPC: %5u freeing task\n", task->tk_pid);
865 mempool_free(task, rpc_task_mempool);
866 }
867 rpc_release_calldata(tk_ops, calldata);
868}
869
870static void rpc_async_release(struct work_struct *work)
871{
872 rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
873}
874
875static void rpc_release_resources_task(struct rpc_task *task)
876{
877 if (task->tk_rqstp)
878 xprt_release(task);
879 if (task->tk_msg.rpc_cred) {
880 put_rpccred(task->tk_msg.rpc_cred);
881 task->tk_msg.rpc_cred = NULL;
882 }
883 rpc_task_release_client(task);
884}
885
886static void rpc_final_put_task(struct rpc_task *task,
887 struct workqueue_struct *q)
888{
889 if (q != NULL) {
890 INIT_WORK(&task->u.tk_work, rpc_async_release);
891 queue_work(q, &task->u.tk_work);
892 } else
893 rpc_free_task(task);
894}
895
896static void rpc_do_put_task(struct rpc_task *task, struct workqueue_struct *q)
897{
898 if (atomic_dec_and_test(&task->tk_count)) {
899 rpc_release_resources_task(task);
900 rpc_final_put_task(task, q);
901 }
902}
903
904void rpc_put_task(struct rpc_task *task)
905{
906 rpc_do_put_task(task, NULL);
907}
908EXPORT_SYMBOL_GPL(rpc_put_task);
909
910void rpc_put_task_async(struct rpc_task *task)
911{
912 rpc_do_put_task(task, task->tk_workqueue);
913}
914EXPORT_SYMBOL_GPL(rpc_put_task_async);
915
916static void rpc_release_task(struct rpc_task *task)
917{
918 dprintk("RPC: %5u release task\n", task->tk_pid);
919
920 BUG_ON (RPC_IS_QUEUED(task));
921
922 rpc_release_resources_task(task);
923
924 /*
925 * Note: at this point we have been removed from rpc_clnt->cl_tasks,
926 * so it should be safe to use task->tk_count as a test for whether
927 * or not any other processes still hold references to our rpc_task.
928 */
929 if (atomic_read(&task->tk_count) != 1 + !RPC_IS_ASYNC(task)) {
930 /* Wake up anyone who may be waiting for task completion */
931 if (!rpc_complete_task(task))
932 return;
933 } else {
934 if (!atomic_dec_and_test(&task->tk_count))
935 return;
936 }
937 rpc_final_put_task(task, task->tk_workqueue);
938}
939
940int rpciod_up(void)
941{
942 return try_module_get(THIS_MODULE) ? 0 : -EINVAL;
943}
944
945void rpciod_down(void)
946{
947 module_put(THIS_MODULE);
948}
949
950/*
951 * Start up the rpciod workqueue.
952 */
953static int rpciod_start(void)
954{
955 struct workqueue_struct *wq;
956
957 /*
958 * Create the rpciod thread and wait for it to start.
959 */
960 dprintk("RPC: creating workqueue rpciod\n");
961 wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM, 0);
962 rpciod_workqueue = wq;
963 return rpciod_workqueue != NULL;
964}
965
966static void rpciod_stop(void)
967{
968 struct workqueue_struct *wq = NULL;
969
970 if (rpciod_workqueue == NULL)
971 return;
972 dprintk("RPC: destroying workqueue rpciod\n");
973
974 wq = rpciod_workqueue;
975 rpciod_workqueue = NULL;
976 destroy_workqueue(wq);
977}
978
979void
980rpc_destroy_mempool(void)
981{
982 rpciod_stop();
983 if (rpc_buffer_mempool)
984 mempool_destroy(rpc_buffer_mempool);
985 if (rpc_task_mempool)
986 mempool_destroy(rpc_task_mempool);
987 if (rpc_task_slabp)
988 kmem_cache_destroy(rpc_task_slabp);
989 if (rpc_buffer_slabp)
990 kmem_cache_destroy(rpc_buffer_slabp);
991 rpc_destroy_wait_queue(&delay_queue);
992}
993
994int
995rpc_init_mempool(void)
996{
997 /*
998 * The following is not strictly a mempool initialisation,
999 * but there is no harm in doing it here
1000 */
1001 rpc_init_wait_queue(&delay_queue, "delayq");
1002 if (!rpciod_start())
1003 goto err_nomem;
1004
1005 rpc_task_slabp = kmem_cache_create("rpc_tasks",
1006 sizeof(struct rpc_task),
1007 0, SLAB_HWCACHE_ALIGN,
1008 NULL);
1009 if (!rpc_task_slabp)
1010 goto err_nomem;
1011 rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1012 RPC_BUFFER_MAXSIZE,
1013 0, SLAB_HWCACHE_ALIGN,
1014 NULL);
1015 if (!rpc_buffer_slabp)
1016 goto err_nomem;
1017 rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
1018 rpc_task_slabp);
1019 if (!rpc_task_mempool)
1020 goto err_nomem;
1021 rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
1022 rpc_buffer_slabp);
1023 if (!rpc_buffer_mempool)
1024 goto err_nomem;
1025 return 0;
1026err_nomem:
1027 rpc_destroy_mempool();
1028 return -ENOMEM;
1029}