blob: a1ab4eed41f4b5a495f18573aef04b3457403ba3 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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/smp_lock.h>
20#include <linux/spinlock.h>
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080021#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
23#include <linux/sunrpc/clnt.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
25#ifdef RPC_DEBUG
26#define RPCDBG_FACILITY RPCDBG_SCHED
27#define RPC_TASK_MAGIC_ID 0xf00baa
28static int rpc_task_id;
29#endif
30
31/*
32 * RPC slabs and memory pools
33 */
34#define RPC_BUFFER_MAXSIZE (2048)
35#define RPC_BUFFER_POOLSIZE (8)
36#define RPC_TASK_POOLSIZE (8)
Eric Dumazetba899662005-08-26 12:05:31 -070037static kmem_cache_t *rpc_task_slabp __read_mostly;
38static kmem_cache_t *rpc_buffer_slabp __read_mostly;
39static mempool_t *rpc_task_mempool __read_mostly;
40static mempool_t *rpc_buffer_mempool __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42static void __rpc_default_timer(struct rpc_task *task);
43static void rpciod_killall(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -070044static void rpc_async_schedule(void *);
45
46/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 * RPC tasks sit here while waiting for conditions to improve.
48 */
49static RPC_WAITQ(delay_queue, "delayq");
50
51/*
52 * All RPC tasks are linked into this list
53 */
54static LIST_HEAD(all_tasks);
55
56/*
57 * rpciod-related stuff
58 */
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080059static DEFINE_MUTEX(rpciod_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070060static unsigned int rpciod_users;
Trond Myklebust24c5d9d2006-03-20 13:44:08 -050061struct workqueue_struct *rpciod_workqueue;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63/*
64 * Spinlock for other critical sections of code.
65 */
66static DEFINE_SPINLOCK(rpc_sched_lock);
67
68/*
69 * Disable the timer for a given RPC task. Should be called with
70 * queue->lock and bh_disabled in order to avoid races within
71 * rpc_run_timer().
72 */
73static inline void
74__rpc_disable_timer(struct rpc_task *task)
75{
76 dprintk("RPC: %4d disabling timer\n", task->tk_pid);
77 task->tk_timeout_fn = NULL;
78 task->tk_timeout = 0;
79}
80
81/*
82 * Run a timeout function.
83 * We use the callback in order to allow __rpc_wake_up_task()
84 * and friends to disable the timer synchronously on SMP systems
85 * without calling del_timer_sync(). The latter could cause a
86 * deadlock if called while we're holding spinlocks...
87 */
88static void rpc_run_timer(struct rpc_task *task)
89{
90 void (*callback)(struct rpc_task *);
91
92 callback = task->tk_timeout_fn;
93 task->tk_timeout_fn = NULL;
94 if (callback && RPC_IS_QUEUED(task)) {
95 dprintk("RPC: %4d running timer\n", task->tk_pid);
96 callback(task);
97 }
98 smp_mb__before_clear_bit();
99 clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate);
100 smp_mb__after_clear_bit();
101}
102
103/*
104 * Set up a timer for the current task.
105 */
106static inline void
107__rpc_add_timer(struct rpc_task *task, rpc_action timer)
108{
109 if (!task->tk_timeout)
110 return;
111
112 dprintk("RPC: %4d setting alarm for %lu ms\n",
113 task->tk_pid, task->tk_timeout * 1000 / HZ);
114
115 if (timer)
116 task->tk_timeout_fn = timer;
117 else
118 task->tk_timeout_fn = __rpc_default_timer;
119 set_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate);
120 mod_timer(&task->tk_timer, jiffies + task->tk_timeout);
121}
122
123/*
124 * Delete any timer for the current task. Because we use del_timer_sync(),
125 * this function should never be called while holding queue->lock.
126 */
127static void
128rpc_delete_timer(struct rpc_task *task)
129{
130 if (RPC_IS_QUEUED(task))
131 return;
132 if (test_and_clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate)) {
133 del_singleshot_timer_sync(&task->tk_timer);
134 dprintk("RPC: %4d deleting timer\n", task->tk_pid);
135 }
136}
137
138/*
139 * Add new request to a priority queue.
140 */
141static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue, struct rpc_task *task)
142{
143 struct list_head *q;
144 struct rpc_task *t;
145
146 INIT_LIST_HEAD(&task->u.tk_wait.links);
147 q = &queue->tasks[task->tk_priority];
148 if (unlikely(task->tk_priority > queue->maxpriority))
149 q = &queue->tasks[queue->maxpriority];
150 list_for_each_entry(t, q, u.tk_wait.list) {
151 if (t->tk_cookie == task->tk_cookie) {
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, struct rpc_task *task)
168{
169 BUG_ON (RPC_IS_QUEUED(task));
170
171 if (RPC_IS_PRIORITY(queue))
172 __rpc_add_wait_queue_priority(queue, task);
173 else if (RPC_IS_SWAPPER(task))
174 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
175 else
176 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
177 task->u.tk_wait.rpc_waitq = queue;
Chuck Levere19b63d2006-03-20 13:44:15 -0500178 queue->qlen++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 rpc_set_queued(task);
180
181 dprintk("RPC: %4d added to queue %p \"%s\"\n",
182 task->tk_pid, queue, rpc_qname(queue));
183}
184
185/*
186 * Remove request from a priority queue.
187 */
188static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
189{
190 struct rpc_task *t;
191
192 if (!list_empty(&task->u.tk_wait.links)) {
193 t = list_entry(task->u.tk_wait.links.next, struct rpc_task, u.tk_wait.list);
194 list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);
195 list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);
196 }
197 list_del(&task->u.tk_wait.list);
198}
199
200/*
201 * Remove request from queue.
202 * Note: must be called with spin lock held.
203 */
204static void __rpc_remove_wait_queue(struct rpc_task *task)
205{
206 struct rpc_wait_queue *queue;
207 queue = task->u.tk_wait.rpc_waitq;
208
209 if (RPC_IS_PRIORITY(queue))
210 __rpc_remove_wait_queue_priority(task);
211 else
212 list_del(&task->u.tk_wait.list);
Chuck Levere19b63d2006-03-20 13:44:15 -0500213 queue->qlen--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 dprintk("RPC: %4d removed from queue %p \"%s\"\n",
215 task->tk_pid, queue, rpc_qname(queue));
216}
217
218static inline void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
219{
220 queue->priority = priority;
221 queue->count = 1 << (priority * 2);
222}
223
224static inline void rpc_set_waitqueue_cookie(struct rpc_wait_queue *queue, unsigned long cookie)
225{
226 queue->cookie = cookie;
227 queue->nr = RPC_BATCH_COUNT;
228}
229
230static inline void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
231{
232 rpc_set_waitqueue_priority(queue, queue->maxpriority);
233 rpc_set_waitqueue_cookie(queue, 0);
234}
235
236static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, int maxprio)
237{
238 int i;
239
240 spin_lock_init(&queue->lock);
241 for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
242 INIT_LIST_HEAD(&queue->tasks[i]);
243 queue->maxpriority = maxprio;
244 rpc_reset_waitqueue_priority(queue);
245#ifdef RPC_DEBUG
246 queue->name = qname;
247#endif
248}
249
250void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
251{
252 __rpc_init_priority_wait_queue(queue, qname, RPC_PRIORITY_HIGH);
253}
254
255void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
256{
257 __rpc_init_priority_wait_queue(queue, qname, 0);
258}
259EXPORT_SYMBOL(rpc_init_wait_queue);
260
Trond Myklebust44c28872006-01-03 09:55:06 +0100261static int rpc_wait_bit_interruptible(void *word)
262{
263 if (signal_pending(current))
264 return -ERESTARTSYS;
265 schedule();
266 return 0;
267}
268
269/*
270 * Mark an RPC call as having completed by clearing the 'active' bit
271 */
272static inline void rpc_mark_complete_task(struct rpc_task *task)
273{
274 rpc_clear_active(task);
275 wake_up_bit(&task->tk_runstate, RPC_TASK_ACTIVE);
276}
277
278/*
279 * Allow callers to wait for completion of an RPC call
280 */
281int __rpc_wait_for_completion_task(struct rpc_task *task, int (*action)(void *))
282{
283 if (action == NULL)
284 action = rpc_wait_bit_interruptible;
285 return wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
286 action, TASK_INTERRUPTIBLE);
287}
288EXPORT_SYMBOL(__rpc_wait_for_completion_task);
289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290/*
291 * Make an RPC task runnable.
292 *
293 * Note: If the task is ASYNC, this must be called with
294 * the spinlock held to protect the wait queue operation.
295 */
296static void rpc_make_runnable(struct rpc_task *task)
297{
298 int do_ret;
299
300 BUG_ON(task->tk_timeout_fn);
301 do_ret = rpc_test_and_set_running(task);
302 rpc_clear_queued(task);
303 if (do_ret)
304 return;
305 if (RPC_IS_ASYNC(task)) {
306 int status;
307
308 INIT_WORK(&task->u.tk_work, rpc_async_schedule, (void *)task);
309 status = queue_work(task->tk_workqueue, &task->u.tk_work);
310 if (status < 0) {
311 printk(KERN_WARNING "RPC: failed to add task to queue: error: %d!\n", status);
312 task->tk_status = status;
313 return;
314 }
315 } else
Trond Myklebust96651ab2005-06-22 17:16:21 +0000316 wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317}
318
319/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 * Prepare for sleeping on a wait queue.
321 * By always appending tasks to the list we ensure FIFO behavior.
322 * NB: An RPC task will only receive interrupt-driven events as long
323 * as it's on a wait queue.
324 */
325static void __rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
326 rpc_action action, rpc_action timer)
327{
328 dprintk("RPC: %4d sleep_on(queue \"%s\" time %ld)\n", task->tk_pid,
329 rpc_qname(q), jiffies);
330
331 if (!RPC_IS_ASYNC(task) && !RPC_IS_ACTIVATED(task)) {
332 printk(KERN_ERR "RPC: Inactive synchronous task put to sleep!\n");
333 return;
334 }
335
336 /* Mark the task as being activated if so needed */
Trond Myklebust44c28872006-01-03 09:55:06 +0100337 rpc_set_active(task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
339 __rpc_add_wait_queue(q, task);
340
341 BUG_ON(task->tk_callback != NULL);
342 task->tk_callback = action;
343 __rpc_add_timer(task, timer);
344}
345
346void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
347 rpc_action action, rpc_action timer)
348{
349 /*
350 * Protect the queue operations.
351 */
352 spin_lock_bh(&q->lock);
353 __rpc_sleep_on(q, task, action, timer);
354 spin_unlock_bh(&q->lock);
355}
356
357/**
358 * __rpc_do_wake_up_task - wake up a single rpc_task
359 * @task: task to be woken up
360 *
361 * Caller must hold queue->lock, and have cleared the task queued flag.
362 */
363static void __rpc_do_wake_up_task(struct rpc_task *task)
364{
365 dprintk("RPC: %4d __rpc_wake_up_task (now %ld)\n", task->tk_pid, jiffies);
366
367#ifdef RPC_DEBUG
368 BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
369#endif
370 /* Has the task been executed yet? If not, we cannot wake it up! */
371 if (!RPC_IS_ACTIVATED(task)) {
372 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
373 return;
374 }
375
376 __rpc_disable_timer(task);
377 __rpc_remove_wait_queue(task);
378
379 rpc_make_runnable(task);
380
381 dprintk("RPC: __rpc_wake_up_task done\n");
382}
383
384/*
385 * Wake up the specified task
386 */
387static void __rpc_wake_up_task(struct rpc_task *task)
388{
389 if (rpc_start_wakeup(task)) {
390 if (RPC_IS_QUEUED(task))
391 __rpc_do_wake_up_task(task);
392 rpc_finish_wakeup(task);
393 }
394}
395
396/*
397 * Default timeout handler if none specified by user
398 */
399static void
400__rpc_default_timer(struct rpc_task *task)
401{
402 dprintk("RPC: %d timeout (default timer)\n", task->tk_pid);
403 task->tk_status = -ETIMEDOUT;
404 rpc_wake_up_task(task);
405}
406
407/*
408 * Wake up the specified task
409 */
410void rpc_wake_up_task(struct rpc_task *task)
411{
412 if (rpc_start_wakeup(task)) {
413 if (RPC_IS_QUEUED(task)) {
414 struct rpc_wait_queue *queue = task->u.tk_wait.rpc_waitq;
415
416 spin_lock_bh(&queue->lock);
417 __rpc_do_wake_up_task(task);
418 spin_unlock_bh(&queue->lock);
419 }
420 rpc_finish_wakeup(task);
421 }
422}
423
424/*
425 * Wake up the next task on a priority queue.
426 */
427static struct rpc_task * __rpc_wake_up_next_priority(struct rpc_wait_queue *queue)
428{
429 struct list_head *q;
430 struct rpc_task *task;
431
432 /*
433 * Service a batch of tasks from a single cookie.
434 */
435 q = &queue->tasks[queue->priority];
436 if (!list_empty(q)) {
437 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
438 if (queue->cookie == task->tk_cookie) {
439 if (--queue->nr)
440 goto out;
441 list_move_tail(&task->u.tk_wait.list, q);
442 }
443 /*
444 * Check if we need to switch queues.
445 */
446 if (--queue->count)
447 goto new_cookie;
448 }
449
450 /*
451 * Service the next queue.
452 */
453 do {
454 if (q == &queue->tasks[0])
455 q = &queue->tasks[queue->maxpriority];
456 else
457 q = q - 1;
458 if (!list_empty(q)) {
459 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
460 goto new_queue;
461 }
462 } while (q != &queue->tasks[queue->priority]);
463
464 rpc_reset_waitqueue_priority(queue);
465 return NULL;
466
467new_queue:
468 rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
469new_cookie:
470 rpc_set_waitqueue_cookie(queue, task->tk_cookie);
471out:
472 __rpc_wake_up_task(task);
473 return task;
474}
475
476/*
477 * Wake up the next task on the wait queue.
478 */
479struct rpc_task * rpc_wake_up_next(struct rpc_wait_queue *queue)
480{
481 struct rpc_task *task = NULL;
482
483 dprintk("RPC: wake_up_next(%p \"%s\")\n", queue, rpc_qname(queue));
484 spin_lock_bh(&queue->lock);
485 if (RPC_IS_PRIORITY(queue))
486 task = __rpc_wake_up_next_priority(queue);
487 else {
488 task_for_first(task, &queue->tasks[0])
489 __rpc_wake_up_task(task);
490 }
491 spin_unlock_bh(&queue->lock);
492
493 return task;
494}
495
496/**
497 * rpc_wake_up - wake up all rpc_tasks
498 * @queue: rpc_wait_queue on which the tasks are sleeping
499 *
500 * Grabs queue->lock
501 */
502void rpc_wake_up(struct rpc_wait_queue *queue)
503{
Trond Myklebuste6d83d52006-03-13 21:20:48 -0800504 struct rpc_task *task, *next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 struct list_head *head;
Trond Myklebuste6d83d52006-03-13 21:20:48 -0800506
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 spin_lock_bh(&queue->lock);
508 head = &queue->tasks[queue->maxpriority];
509 for (;;) {
Trond Myklebuste6d83d52006-03-13 21:20:48 -0800510 list_for_each_entry_safe(task, next, head, u.tk_wait.list)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 __rpc_wake_up_task(task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 if (head == &queue->tasks[0])
513 break;
514 head--;
515 }
516 spin_unlock_bh(&queue->lock);
517}
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{
Trond Myklebuste6d83d52006-03-13 21:20:48 -0800528 struct rpc_task *task, *next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 struct list_head *head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
531 spin_lock_bh(&queue->lock);
532 head = &queue->tasks[queue->maxpriority];
533 for (;;) {
Trond Myklebuste6d83d52006-03-13 21:20:48 -0800534 list_for_each_entry_safe(task, next, head, u.tk_wait.list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 task->tk_status = status;
536 __rpc_wake_up_task(task);
537 }
538 if (head == &queue->tasks[0])
539 break;
540 head--;
541 }
542 spin_unlock_bh(&queue->lock);
543}
544
Trond Myklebust80147932006-08-31 18:24:08 -0400545static void __rpc_atrun(struct rpc_task *task)
546{
547 rpc_wake_up_task(task);
548}
549
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550/*
551 * Run a task at a later time
552 */
Trond Myklebust80147932006-08-31 18:24:08 -0400553void rpc_delay(struct rpc_task *task, unsigned long delay)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554{
555 task->tk_timeout = delay;
556 rpc_sleep_on(&delay_queue, task, NULL, __rpc_atrun);
557}
558
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559/*
Trond Myklebust4ce70ad2006-01-03 09:55:05 +0100560 * Helper to call task->tk_ops->rpc_call_prepare
561 */
562static void rpc_prepare_task(struct rpc_task *task)
563{
564 task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
565}
566
567/*
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100568 * Helper that calls task->tk_ops->rpc_call_done if it exists
Trond Myklebustd05fdb02005-06-22 17:16:19 +0000569 */
Trond Myklebustabbcf282006-01-03 09:55:03 +0100570void rpc_exit_task(struct rpc_task *task)
Trond Myklebustd05fdb02005-06-22 17:16:19 +0000571{
Trond Myklebustabbcf282006-01-03 09:55:03 +0100572 task->tk_action = NULL;
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100573 if (task->tk_ops->rpc_call_done != NULL) {
574 task->tk_ops->rpc_call_done(task, task->tk_calldata);
Trond Myklebustd05fdb02005-06-22 17:16:19 +0000575 if (task->tk_action != NULL) {
Trond Myklebustabbcf282006-01-03 09:55:03 +0100576 WARN_ON(RPC_ASSASSINATED(task));
577 /* Always release the RPC slot and buffer memory */
578 xprt_release(task);
Trond Myklebustd05fdb02005-06-22 17:16:19 +0000579 }
580 }
Trond Myklebustd05fdb02005-06-22 17:16:19 +0000581}
Trond Myklebustabbcf282006-01-03 09:55:03 +0100582EXPORT_SYMBOL(rpc_exit_task);
Trond Myklebustd05fdb02005-06-22 17:16:19 +0000583
584/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 * This is the RPC `scheduler' (or rather, the finite state machine).
586 */
587static int __rpc_execute(struct rpc_task *task)
588{
589 int status = 0;
590
591 dprintk("RPC: %4d rpc_execute flgs %x\n",
592 task->tk_pid, task->tk_flags);
593
594 BUG_ON(RPC_IS_QUEUED(task));
595
Trond Myklebustd05fdb02005-06-22 17:16:19 +0000596 for (;;) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 /*
598 * Garbage collection of pending timers...
599 */
600 rpc_delete_timer(task);
601
602 /*
603 * Execute any pending callback.
604 */
605 if (RPC_DO_CALLBACK(task)) {
606 /* Define a callback save pointer */
607 void (*save_callback)(struct rpc_task *);
608
609 /*
610 * If a callback exists, save it, reset it,
611 * call it.
612 * The save is needed to stop from resetting
613 * another callback set within the callback handler
614 * - Dave
615 */
616 save_callback=task->tk_callback;
617 task->tk_callback=NULL;
618 lock_kernel();
619 save_callback(task);
620 unlock_kernel();
621 }
622
623 /*
624 * Perform the next FSM step.
625 * tk_action may be NULL when the task has been killed
626 * by someone else.
627 */
628 if (!RPC_IS_QUEUED(task)) {
Trond Myklebustabbcf282006-01-03 09:55:03 +0100629 if (task->tk_action == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 break;
Trond Myklebustabbcf282006-01-03 09:55:03 +0100631 lock_kernel();
632 task->tk_action(task);
633 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 }
635
636 /*
637 * Lockless check for whether task is sleeping or not.
638 */
639 if (!RPC_IS_QUEUED(task))
640 continue;
641 rpc_clear_running(task);
642 if (RPC_IS_ASYNC(task)) {
643 /* Careful! we may have raced... */
644 if (RPC_IS_QUEUED(task))
645 return 0;
646 if (rpc_test_and_set_running(task))
647 return 0;
648 continue;
649 }
650
651 /* sync task: sleep here */
652 dprintk("RPC: %4d sync task going to sleep\n", task->tk_pid);
Trond Myklebust96651ab2005-06-22 17:16:21 +0000653 /* Note: Caller should be using rpc_clnt_sigmask() */
654 status = out_of_line_wait_on_bit(&task->tk_runstate,
655 RPC_TASK_QUEUED, rpc_wait_bit_interruptible,
656 TASK_INTERRUPTIBLE);
657 if (status == -ERESTARTSYS) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 /*
659 * When a sync task receives a signal, it exits with
660 * -ERESTARTSYS. In order to catch any callbacks that
661 * clean up after sleeping on some queue, we don't
662 * break the loop here, but go around once more.
663 */
Trond Myklebust96651ab2005-06-22 17:16:21 +0000664 dprintk("RPC: %4d got signal\n", task->tk_pid);
665 task->tk_flags |= RPC_TASK_KILLED;
666 rpc_exit(task, -ERESTARTSYS);
667 rpc_wake_up_task(task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 }
669 rpc_set_running(task);
670 dprintk("RPC: %4d sync task resuming\n", task->tk_pid);
671 }
672
Trond Myklebuste60859a2006-01-03 09:55:10 +0100673 dprintk("RPC: %4d, return %d, status %d\n", task->tk_pid, status, task->tk_status);
Trond Myklebust44c28872006-01-03 09:55:06 +0100674 /* Wake up anyone who is waiting for task completion */
675 rpc_mark_complete_task(task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 /* Release all resources associated with the task */
677 rpc_release_task(task);
678 return status;
679}
680
681/*
682 * User-visible entry point to the scheduler.
683 *
684 * This may be called recursively if e.g. an async NFS task updates
685 * the attributes and finds that dirty pages must be flushed.
686 * NOTE: Upon exit of this function the task is guaranteed to be
687 * released. In particular note that tk_release() will have
688 * been called, so your task memory may have been freed.
689 */
690int
691rpc_execute(struct rpc_task *task)
692{
Trond Myklebust44c28872006-01-03 09:55:06 +0100693 rpc_set_active(task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 rpc_set_running(task);
695 return __rpc_execute(task);
696}
697
698static void rpc_async_schedule(void *arg)
699{
700 __rpc_execute((struct rpc_task *)arg);
701}
702
Chuck Lever02107142006-01-03 09:55:49 +0100703/**
704 * rpc_malloc - allocate an RPC buffer
705 * @task: RPC task that will use this buffer
706 * @size: requested byte size
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 *
708 * We try to ensure that some NFS reads and writes can always proceed
709 * by using a mempool when allocating 'small' buffers.
710 * In order to avoid memory starvation triggering more writebacks of
711 * NFS requests, we use GFP_NOFS rather than GFP_KERNEL.
712 */
Chuck Lever02107142006-01-03 09:55:49 +0100713void * rpc_malloc(struct rpc_task *task, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714{
Chuck Lever02107142006-01-03 09:55:49 +0100715 struct rpc_rqst *req = task->tk_rqstp;
Al Virodd0fc662005-10-07 07:46:04 +0100716 gfp_t gfp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717
718 if (task->tk_flags & RPC_TASK_SWAPPER)
719 gfp = GFP_ATOMIC;
720 else
721 gfp = GFP_NOFS;
722
723 if (size > RPC_BUFFER_MAXSIZE) {
Chuck Lever02107142006-01-03 09:55:49 +0100724 req->rq_buffer = kmalloc(size, gfp);
725 if (req->rq_buffer)
726 req->rq_bufsize = size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 } else {
Chuck Lever02107142006-01-03 09:55:49 +0100728 req->rq_buffer = mempool_alloc(rpc_buffer_mempool, gfp);
729 if (req->rq_buffer)
730 req->rq_bufsize = RPC_BUFFER_MAXSIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 }
Chuck Lever02107142006-01-03 09:55:49 +0100732 return req->rq_buffer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733}
734
Chuck Lever02107142006-01-03 09:55:49 +0100735/**
736 * rpc_free - free buffer allocated via rpc_malloc
737 * @task: RPC task with a buffer to be freed
738 *
739 */
740void rpc_free(struct rpc_task *task)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741{
Chuck Lever02107142006-01-03 09:55:49 +0100742 struct rpc_rqst *req = task->tk_rqstp;
743
744 if (req->rq_buffer) {
745 if (req->rq_bufsize == RPC_BUFFER_MAXSIZE)
746 mempool_free(req->rq_buffer, rpc_buffer_mempool);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 else
Chuck Lever02107142006-01-03 09:55:49 +0100748 kfree(req->rq_buffer);
749 req->rq_buffer = NULL;
750 req->rq_bufsize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 }
752}
753
754/*
755 * Creation and deletion of RPC task structures
756 */
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100757void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, int flags, const struct rpc_call_ops *tk_ops, void *calldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758{
759 memset(task, 0, sizeof(*task));
760 init_timer(&task->tk_timer);
761 task->tk_timer.data = (unsigned long) task;
762 task->tk_timer.function = (void (*)(unsigned long)) rpc_run_timer;
Trond Myklebust44c28872006-01-03 09:55:06 +0100763 atomic_set(&task->tk_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 task->tk_client = clnt;
765 task->tk_flags = flags;
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100766 task->tk_ops = tk_ops;
Trond Myklebust4ce70ad2006-01-03 09:55:05 +0100767 if (tk_ops->rpc_call_prepare != NULL)
768 task->tk_action = rpc_prepare_task;
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100769 task->tk_calldata = calldata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770
771 /* Initialize retry counters */
772 task->tk_garb_retry = 2;
773 task->tk_cred_retry = 2;
774
775 task->tk_priority = RPC_PRIORITY_NORMAL;
776 task->tk_cookie = (unsigned long)current;
777
778 /* Initialize workqueue for async tasks */
779 task->tk_workqueue = rpciod_workqueue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780
781 if (clnt) {
782 atomic_inc(&clnt->cl_users);
783 if (clnt->cl_softrtry)
784 task->tk_flags |= RPC_TASK_SOFT;
785 if (!clnt->cl_intr)
786 task->tk_flags |= RPC_TASK_NOINTR;
787 }
788
789#ifdef RPC_DEBUG
790 task->tk_magic = RPC_TASK_MAGIC_ID;
791 task->tk_pid = rpc_task_id++;
792#endif
793 /* Add to global list of all tasks */
794 spin_lock(&rpc_sched_lock);
795 list_add_tail(&task->tk_task, &all_tasks);
796 spin_unlock(&rpc_sched_lock);
797
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100798 BUG_ON(task->tk_ops == NULL);
799
Chuck Leveref759a22006-03-20 13:44:17 -0500800 /* starting timestamp */
801 task->tk_start = jiffies;
802
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 dprintk("RPC: %4d new task procpid %d\n", task->tk_pid,
804 current->pid);
805}
806
807static struct rpc_task *
808rpc_alloc_task(void)
809{
810 return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
811}
812
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100813static void rpc_free_task(struct rpc_task *task)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814{
815 dprintk("RPC: %4d freeing task\n", task->tk_pid);
816 mempool_free(task, rpc_task_mempool);
817}
818
819/*
820 * Create a new task for the specified client. We have to
821 * clean up after an allocation failure, as the client may
822 * have specified "oneshot".
823 */
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100824struct rpc_task *rpc_new_task(struct rpc_clnt *clnt, int flags, const struct rpc_call_ops *tk_ops, void *calldata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825{
826 struct rpc_task *task;
827
828 task = rpc_alloc_task();
829 if (!task)
830 goto cleanup;
831
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100832 rpc_init_task(task, clnt, flags, tk_ops, calldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833
834 dprintk("RPC: %4d allocated task\n", task->tk_pid);
835 task->tk_flags |= RPC_TASK_DYNAMIC;
836out:
837 return task;
838
839cleanup:
840 /* Check whether to release the client */
841 if (clnt) {
842 printk("rpc_new_task: failed, users=%d, oneshot=%d\n",
843 atomic_read(&clnt->cl_users), clnt->cl_oneshot);
844 atomic_inc(&clnt->cl_users); /* pretend we were used ... */
845 rpc_release_client(clnt);
846 }
847 goto out;
848}
849
850void rpc_release_task(struct rpc_task *task)
851{
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100852 const struct rpc_call_ops *tk_ops = task->tk_ops;
853 void *calldata = task->tk_calldata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854
855#ifdef RPC_DEBUG
856 BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
857#endif
Trond Myklebust44c28872006-01-03 09:55:06 +0100858 if (!atomic_dec_and_test(&task->tk_count))
859 return;
860 dprintk("RPC: %4d release task\n", task->tk_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861
862 /* Remove from global task list */
863 spin_lock(&rpc_sched_lock);
864 list_del(&task->tk_task);
865 spin_unlock(&rpc_sched_lock);
866
867 BUG_ON (RPC_IS_QUEUED(task));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868
869 /* Synchronously delete any running timer */
870 rpc_delete_timer(task);
871
872 /* Release resources */
873 if (task->tk_rqstp)
874 xprt_release(task);
875 if (task->tk_msg.rpc_cred)
876 rpcauth_unbindcred(task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 if (task->tk_client) {
878 rpc_release_client(task->tk_client);
879 task->tk_client = NULL;
880 }
881
882#ifdef RPC_DEBUG
883 task->tk_magic = 0;
884#endif
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100885 if (task->tk_flags & RPC_TASK_DYNAMIC)
886 rpc_free_task(task);
887 if (tk_ops->rpc_release)
888 tk_ops->rpc_release(calldata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889}
890
891/**
Trond Myklebust44c28872006-01-03 09:55:06 +0100892 * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
Martin Waitz99acf042006-02-01 03:06:56 -0800893 * @clnt: pointer to RPC client
894 * @flags: RPC flags
895 * @ops: RPC call ops
896 * @data: user call data
Trond Myklebust44c28872006-01-03 09:55:06 +0100897 */
898struct rpc_task *rpc_run_task(struct rpc_clnt *clnt, int flags,
899 const struct rpc_call_ops *ops,
900 void *data)
901{
902 struct rpc_task *task;
903 task = rpc_new_task(clnt, flags, ops, data);
Trond Myklebust7a1218a2006-03-20 18:11:10 -0500904 if (task == NULL) {
905 if (ops->rpc_release != NULL)
906 ops->rpc_release(data);
Trond Myklebust44c28872006-01-03 09:55:06 +0100907 return ERR_PTR(-ENOMEM);
Trond Myklebust7a1218a2006-03-20 18:11:10 -0500908 }
Trond Myklebust44c28872006-01-03 09:55:06 +0100909 atomic_inc(&task->tk_count);
910 rpc_execute(task);
911 return task;
912}
913EXPORT_SYMBOL(rpc_run_task);
914
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915/*
916 * Kill all tasks for the given client.
917 * XXX: kill their descendants as well?
918 */
919void rpc_killall_tasks(struct rpc_clnt *clnt)
920{
921 struct rpc_task *rovr;
922 struct list_head *le;
923
924 dprintk("RPC: killing all tasks for client %p\n", clnt);
925
926 /*
927 * Spin lock all_tasks to prevent changes...
928 */
929 spin_lock(&rpc_sched_lock);
930 alltask_for_each(rovr, le, &all_tasks) {
931 if (! RPC_IS_ACTIVATED(rovr))
932 continue;
933 if (!clnt || rovr->tk_client == clnt) {
934 rovr->tk_flags |= RPC_TASK_KILLED;
935 rpc_exit(rovr, -EIO);
936 rpc_wake_up_task(rovr);
937 }
938 }
939 spin_unlock(&rpc_sched_lock);
940}
941
942static DECLARE_MUTEX_LOCKED(rpciod_running);
943
944static void rpciod_killall(void)
945{
946 unsigned long flags;
947
948 while (!list_empty(&all_tasks)) {
949 clear_thread_flag(TIF_SIGPENDING);
950 rpc_killall_tasks(NULL);
951 flush_workqueue(rpciod_workqueue);
952 if (!list_empty(&all_tasks)) {
953 dprintk("rpciod_killall: waiting for tasks to exit\n");
954 yield();
955 }
956 }
957
958 spin_lock_irqsave(&current->sighand->siglock, flags);
959 recalc_sigpending();
960 spin_unlock_irqrestore(&current->sighand->siglock, flags);
961}
962
963/*
964 * Start up the rpciod process if it's not already running.
965 */
966int
967rpciod_up(void)
968{
969 struct workqueue_struct *wq;
970 int error = 0;
971
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800972 mutex_lock(&rpciod_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973 dprintk("rpciod_up: users %d\n", rpciod_users);
974 rpciod_users++;
975 if (rpciod_workqueue)
976 goto out;
977 /*
978 * If there's no pid, we should be the first user.
979 */
980 if (rpciod_users > 1)
981 printk(KERN_WARNING "rpciod_up: no workqueue, %d users??\n", rpciod_users);
982 /*
983 * Create the rpciod thread and wait for it to start.
984 */
985 error = -ENOMEM;
986 wq = create_workqueue("rpciod");
987 if (wq == NULL) {
988 printk(KERN_WARNING "rpciod_up: create workqueue failed, error=%d\n", error);
989 rpciod_users--;
990 goto out;
991 }
992 rpciod_workqueue = wq;
993 error = 0;
994out:
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800995 mutex_unlock(&rpciod_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 return error;
997}
998
999void
1000rpciod_down(void)
1001{
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -08001002 mutex_lock(&rpciod_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 dprintk("rpciod_down sema %d\n", rpciod_users);
1004 if (rpciod_users) {
1005 if (--rpciod_users)
1006 goto out;
1007 } else
1008 printk(KERN_WARNING "rpciod_down: no users??\n");
1009
1010 if (!rpciod_workqueue) {
1011 dprintk("rpciod_down: Nothing to do!\n");
1012 goto out;
1013 }
1014 rpciod_killall();
1015
1016 destroy_workqueue(rpciod_workqueue);
1017 rpciod_workqueue = NULL;
1018 out:
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -08001019 mutex_unlock(&rpciod_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020}
1021
1022#ifdef RPC_DEBUG
1023void rpc_show_tasks(void)
1024{
1025 struct list_head *le;
1026 struct rpc_task *t;
1027
1028 spin_lock(&rpc_sched_lock);
1029 if (list_empty(&all_tasks)) {
1030 spin_unlock(&rpc_sched_lock);
1031 return;
1032 }
1033 printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
Trond Myklebust963d8fe2006-01-03 09:55:04 +01001034 "-rpcwait -action- ---ops--\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 alltask_for_each(t, le, &all_tasks) {
1036 const char *rpc_waitq = "none";
1037
1038 if (RPC_IS_QUEUED(t))
1039 rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
1040
1041 printk("%05d %04d %04x %06d %8p %6d %8p %08ld %8s %8p %8p\n",
1042 t->tk_pid,
1043 (t->tk_msg.rpc_proc ? t->tk_msg.rpc_proc->p_proc : -1),
1044 t->tk_flags, t->tk_status,
1045 t->tk_client,
1046 (t->tk_client ? t->tk_client->cl_prog : 0),
1047 t->tk_rqstp, t->tk_timeout,
1048 rpc_waitq,
Trond Myklebust963d8fe2006-01-03 09:55:04 +01001049 t->tk_action, t->tk_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050 }
1051 spin_unlock(&rpc_sched_lock);
1052}
1053#endif
1054
1055void
1056rpc_destroy_mempool(void)
1057{
1058 if (rpc_buffer_mempool)
1059 mempool_destroy(rpc_buffer_mempool);
1060 if (rpc_task_mempool)
1061 mempool_destroy(rpc_task_mempool);
Alexey Dobriyan1a1d92c2006-09-27 01:49:40 -07001062 if (rpc_task_slabp)
1063 kmem_cache_destroy(rpc_task_slabp);
1064 if (rpc_buffer_slabp)
1065 kmem_cache_destroy(rpc_buffer_slabp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066}
1067
1068int
1069rpc_init_mempool(void)
1070{
1071 rpc_task_slabp = kmem_cache_create("rpc_tasks",
1072 sizeof(struct rpc_task),
1073 0, SLAB_HWCACHE_ALIGN,
1074 NULL, NULL);
1075 if (!rpc_task_slabp)
1076 goto err_nomem;
1077 rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1078 RPC_BUFFER_MAXSIZE,
1079 0, SLAB_HWCACHE_ALIGN,
1080 NULL, NULL);
1081 if (!rpc_buffer_slabp)
1082 goto err_nomem;
Matthew Dobson93d23412006-03-26 01:37:50 -08001083 rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
1084 rpc_task_slabp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 if (!rpc_task_mempool)
1086 goto err_nomem;
Matthew Dobson93d23412006-03-26 01:37:50 -08001087 rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
1088 rpc_buffer_slabp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 if (!rpc_buffer_mempool)
1090 goto err_nomem;
1091 return 0;
1092err_nomem:
1093 rpc_destroy_mempool();
1094 return -ENOMEM;
1095}