SUNRPC: Fix a bug in rpcauth_prune_expired
[linux-3.10.git] / net / sunrpc / sched.c
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 #define RPC_TASK_MAGIC_ID       0xf00baa
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)
37 static struct kmem_cache        *rpc_task_slabp __read_mostly;
38 static struct kmem_cache        *rpc_buffer_slabp __read_mostly;
39 static mempool_t        *rpc_task_mempool __read_mostly;
40 static mempool_t        *rpc_buffer_mempool __read_mostly;
41
42 static void                     rpc_async_schedule(struct work_struct *);
43 static void                      rpc_release_task(struct rpc_task *task);
44 static void __rpc_queue_timer_fn(unsigned long ptr);
45
46 /*
47  * RPC tasks sit here while waiting for conditions to improve.
48  */
49 static struct rpc_wait_queue delay_queue;
50
51 /*
52  * rpciod-related stuff
53  */
54 struct workqueue_struct *rpciod_workqueue;
55
56 /*
57  * Disable the timer for a given RPC task. Should be called with
58  * queue->lock and bh_disabled in order to avoid races within
59  * rpc_run_timer().
60  */
61 static void
62 __rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
63 {
64         if (task->tk_timeout == 0)
65                 return;
66         dprintk("RPC: %5u disabling timer\n", task->tk_pid);
67         task->tk_timeout = 0;
68         list_del(&task->u.tk_wait.timer_list);
69         if (list_empty(&queue->timer_list.list))
70                 del_timer(&queue->timer_list.timer);
71 }
72
73 static void
74 rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)
75 {
76         queue->timer_list.expires = expires;
77         mod_timer(&queue->timer_list.timer, expires);
78 }
79
80 /*
81  * Set up a timer for the current task.
82  */
83 static void
84 __rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
85 {
86         if (!task->tk_timeout)
87                 return;
88
89         dprintk("RPC: %5u setting alarm for %lu ms\n",
90                         task->tk_pid, task->tk_timeout * 1000 / HZ);
91
92         task->u.tk_wait.expires = jiffies + task->tk_timeout;
93         if (list_empty(&queue->timer_list.list) || time_before(task->u.tk_wait.expires, queue->timer_list.expires))
94                 rpc_set_queue_timer(queue, task->u.tk_wait.expires);
95         list_add(&task->u.tk_wait.timer_list, &queue->timer_list.list);
96 }
97
98 /*
99  * Add new request to a priority queue.
100  */
101 static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue, struct rpc_task *task)
102 {
103         struct list_head *q;
104         struct rpc_task *t;
105
106         INIT_LIST_HEAD(&task->u.tk_wait.links);
107         q = &queue->tasks[task->tk_priority];
108         if (unlikely(task->tk_priority > queue->maxpriority))
109                 q = &queue->tasks[queue->maxpriority];
110         list_for_each_entry(t, q, u.tk_wait.list) {
111                 if (t->tk_owner == task->tk_owner) {
112                         list_add_tail(&task->u.tk_wait.list, &t->u.tk_wait.links);
113                         return;
114                 }
115         }
116         list_add_tail(&task->u.tk_wait.list, q);
117 }
118
119 /*
120  * Add new request to wait queue.
121  *
122  * Swapper tasks always get inserted at the head of the queue.
123  * This should avoid many nasty memory deadlocks and hopefully
124  * improve overall performance.
125  * Everyone else gets appended to the queue to ensure proper FIFO behavior.
126  */
127 static void __rpc_add_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
128 {
129         BUG_ON (RPC_IS_QUEUED(task));
130
131         if (RPC_IS_PRIORITY(queue))
132                 __rpc_add_wait_queue_priority(queue, task);
133         else if (RPC_IS_SWAPPER(task))
134                 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
135         else
136                 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
137         task->tk_waitqueue = queue;
138         queue->qlen++;
139         rpc_set_queued(task);
140
141         dprintk("RPC: %5u added to queue %p \"%s\"\n",
142                         task->tk_pid, queue, rpc_qname(queue));
143 }
144
145 /*
146  * Remove request from a priority queue.
147  */
148 static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
149 {
150         struct rpc_task *t;
151
152         if (!list_empty(&task->u.tk_wait.links)) {
153                 t = list_entry(task->u.tk_wait.links.next, struct rpc_task, u.tk_wait.list);
154                 list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);
155                 list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);
156         }
157 }
158
159 /*
160  * Remove request from queue.
161  * Note: must be called with spin lock held.
162  */
163 static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
164 {
165         __rpc_disable_timer(queue, task);
166         if (RPC_IS_PRIORITY(queue))
167                 __rpc_remove_wait_queue_priority(task);
168         list_del(&task->u.tk_wait.list);
169         queue->qlen--;
170         dprintk("RPC: %5u removed from queue %p \"%s\"\n",
171                         task->tk_pid, queue, rpc_qname(queue));
172 }
173
174 static inline void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
175 {
176         queue->priority = priority;
177         queue->count = 1 << (priority * 2);
178 }
179
180 static inline void rpc_set_waitqueue_owner(struct rpc_wait_queue *queue, pid_t pid)
181 {
182         queue->owner = pid;
183         queue->nr = RPC_BATCH_COUNT;
184 }
185
186 static inline void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
187 {
188         rpc_set_waitqueue_priority(queue, queue->maxpriority);
189         rpc_set_waitqueue_owner(queue, 0);
190 }
191
192 static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
193 {
194         int i;
195
196         spin_lock_init(&queue->lock);
197         for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
198                 INIT_LIST_HEAD(&queue->tasks[i]);
199         queue->maxpriority = nr_queues - 1;
200         rpc_reset_waitqueue_priority(queue);
201         queue->qlen = 0;
202         setup_timer(&queue->timer_list.timer, __rpc_queue_timer_fn, (unsigned long)queue);
203         INIT_LIST_HEAD(&queue->timer_list.list);
204 #ifdef RPC_DEBUG
205         queue->name = qname;
206 #endif
207 }
208
209 void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
210 {
211         __rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY);
212 }
213 EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue);
214
215 void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
216 {
217         __rpc_init_priority_wait_queue(queue, qname, 1);
218 }
219 EXPORT_SYMBOL_GPL(rpc_init_wait_queue);
220
221 void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)
222 {
223         del_timer_sync(&queue->timer_list.timer);
224 }
225 EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
226
227 static int rpc_wait_bit_killable(void *word)
228 {
229         if (fatal_signal_pending(current))
230                 return -ERESTARTSYS;
231         schedule();
232         return 0;
233 }
234
235 #ifdef RPC_DEBUG
236 static void rpc_task_set_debuginfo(struct rpc_task *task)
237 {
238         static atomic_t rpc_pid;
239
240         task->tk_magic = RPC_TASK_MAGIC_ID;
241         task->tk_pid = atomic_inc_return(&rpc_pid);
242 }
243 #else
244 static inline void rpc_task_set_debuginfo(struct rpc_task *task)
245 {
246 }
247 #endif
248
249 static void rpc_set_active(struct rpc_task *task)
250 {
251         struct rpc_clnt *clnt;
252         if (test_and_set_bit(RPC_TASK_ACTIVE, &task->tk_runstate) != 0)
253                 return;
254         rpc_task_set_debuginfo(task);
255         /* Add to global list of all tasks */
256         clnt = task->tk_client;
257         if (clnt != NULL) {
258                 spin_lock(&clnt->cl_lock);
259                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
260                 spin_unlock(&clnt->cl_lock);
261         }
262 }
263
264 /*
265  * Mark an RPC call as having completed by clearing the 'active' bit
266  */
267 static void rpc_mark_complete_task(struct rpc_task *task)
268 {
269         smp_mb__before_clear_bit();
270         clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
271         smp_mb__after_clear_bit();
272         wake_up_bit(&task->tk_runstate, RPC_TASK_ACTIVE);
273 }
274
275 /*
276  * Allow callers to wait for completion of an RPC call
277  */
278 int __rpc_wait_for_completion_task(struct rpc_task *task, int (*action)(void *))
279 {
280         if (action == NULL)
281                 action = rpc_wait_bit_killable;
282         return wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
283                         action, TASK_KILLABLE);
284 }
285 EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
286
287 /*
288  * Make an RPC task runnable.
289  *
290  * Note: If the task is ASYNC, this must be called with
291  * the spinlock held to protect the wait queue operation.
292  */
293 static void rpc_make_runnable(struct rpc_task *task)
294 {
295         rpc_clear_queued(task);
296         if (rpc_test_and_set_running(task))
297                 return;
298         if (RPC_IS_ASYNC(task)) {
299                 int status;
300
301                 INIT_WORK(&task->u.tk_work, rpc_async_schedule);
302                 status = queue_work(rpciod_workqueue, &task->u.tk_work);
303                 if (status < 0) {
304                         printk(KERN_WARNING "RPC: failed to add task to queue: error: %d!\n", status);
305                         task->tk_status = status;
306                         return;
307                 }
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  */
318 static void __rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
319                         rpc_action action)
320 {
321         dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n",
322                         task->tk_pid, rpc_qname(q), jiffies);
323
324         if (!RPC_IS_ASYNC(task) && !RPC_IS_ACTIVATED(task)) {
325                 printk(KERN_ERR "RPC: Inactive synchronous task put to sleep!\n");
326                 return;
327         }
328
329         __rpc_add_wait_queue(q, task);
330
331         BUG_ON(task->tk_callback != NULL);
332         task->tk_callback = action;
333         __rpc_add_timer(q, task);
334 }
335
336 void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
337                                 rpc_action action)
338 {
339         /* Mark the task as being activated if so needed */
340         rpc_set_active(task);
341
342         /*
343          * Protect the queue operations.
344          */
345         spin_lock_bh(&q->lock);
346         __rpc_sleep_on(q, task, action);
347         spin_unlock_bh(&q->lock);
348 }
349 EXPORT_SYMBOL_GPL(rpc_sleep_on);
350
351 /**
352  * __rpc_do_wake_up_task - wake up a single rpc_task
353  * @queue: wait queue
354  * @task: task to be woken up
355  *
356  * Caller must hold queue->lock, and have cleared the task queued flag.
357  */
358 static void __rpc_do_wake_up_task(struct rpc_wait_queue *queue, struct rpc_task *task)
359 {
360         dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
361                         task->tk_pid, jiffies);
362
363 #ifdef RPC_DEBUG
364         BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
365 #endif
366         /* Has the task been executed yet? If not, we cannot wake it up! */
367         if (!RPC_IS_ACTIVATED(task)) {
368                 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
369                 return;
370         }
371
372         __rpc_remove_wait_queue(queue, task);
373
374         rpc_make_runnable(task);
375
376         dprintk("RPC:       __rpc_wake_up_task done\n");
377 }
378
379 /*
380  * Wake up a queued task while the queue lock is being held
381  */
382 static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
383 {
384         if (RPC_IS_QUEUED(task) && task->tk_waitqueue == queue)
385                 __rpc_do_wake_up_task(queue, task);
386 }
387
388 /*
389  * Tests whether rpc queue is empty
390  */
391 int rpc_queue_empty(struct rpc_wait_queue *queue)
392 {
393         int res;
394
395         spin_lock_bh(&queue->lock);
396         res = queue->qlen;
397         spin_unlock_bh(&queue->lock);
398         return (res == 0);
399 }
400 EXPORT_SYMBOL_GPL(rpc_queue_empty);
401
402 /*
403  * Wake up a task on a specific queue
404  */
405 void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
406 {
407         spin_lock_bh(&queue->lock);
408         rpc_wake_up_task_queue_locked(queue, task);
409         spin_unlock_bh(&queue->lock);
410 }
411 EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
412
413 /*
414  * Wake up the specified task
415  */
416 static void rpc_wake_up_task(struct rpc_task *task)
417 {
418         rpc_wake_up_queued_task(task->tk_waitqueue, task);
419 }
420
421 /*
422  * Wake up the next task on a priority queue.
423  */
424 static 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
464 new_queue:
465         rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
466 new_owner:
467         rpc_set_waitqueue_owner(queue, task->tk_owner);
468 out:
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  */
476 struct 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 }
493 EXPORT_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  */
501 void 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 }
517 EXPORT_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  */
526 void 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 }
544 EXPORT_SYMBOL_GPL(rpc_wake_up_status);
545
546 static 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
570 static 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  */
578 void 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 }
583 EXPORT_SYMBOL_GPL(rpc_delay);
584
585 /*
586  * Helper to call task->tk_ops->rpc_call_prepare
587  */
588 void 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  */
596 void 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 EXPORT_SYMBOL_GPL(rpc_exit_task);
609
610 void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
611 {
612         if (ops->rpc_release != NULL)
613                 ops->rpc_release(calldata);
614 }
615
616 /*
617  * This is the RPC `scheduler' (or rather, the finite state machine).
618  */
619 static void __rpc_execute(struct rpc_task *task)
620 {
621         struct rpc_wait_queue *queue;
622         int task_is_async = RPC_IS_ASYNC(task);
623         int status = 0;
624
625         dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
626                         task->tk_pid, task->tk_flags);
627
628         BUG_ON(RPC_IS_QUEUED(task));
629
630         for (;;) {
631
632                 /*
633                  * Execute any pending callback.
634                  */
635                 if (task->tk_callback) {
636                         void (*save_callback)(struct rpc_task *);
637
638                         /*
639                          * We set tk_callback to NULL before calling it,
640                          * in case it sets the tk_callback field itself:
641                          */
642                         save_callback = task->tk_callback;
643                         task->tk_callback = NULL;
644                         save_callback(task);
645                 }
646
647                 /*
648                  * Perform the next FSM step.
649                  * tk_action may be NULL when the task has been killed
650                  * by someone else.
651                  */
652                 if (!RPC_IS_QUEUED(task)) {
653                         if (task->tk_action == NULL)
654                                 break;
655                         task->tk_action(task);
656                 }
657
658                 /*
659                  * Lockless check for whether task is sleeping or not.
660                  */
661                 if (!RPC_IS_QUEUED(task))
662                         continue;
663                 /*
664                  * The queue->lock protects against races with
665                  * rpc_make_runnable().
666                  *
667                  * Note that once we clear RPC_TASK_RUNNING on an asynchronous
668                  * rpc_task, rpc_make_runnable() can assign it to a
669                  * different workqueue. We therefore cannot assume that the
670                  * rpc_task pointer may still be dereferenced.
671                  */
672                 queue = task->tk_waitqueue;
673                 spin_lock_bh(&queue->lock);
674                 if (!RPC_IS_QUEUED(task)) {
675                         spin_unlock_bh(&queue->lock);
676                         continue;
677                 }
678                 rpc_clear_running(task);
679                 spin_unlock_bh(&queue->lock);
680                 if (task_is_async)
681                         return;
682
683                 /* sync task: sleep here */
684                 dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid);
685                 status = out_of_line_wait_on_bit(&task->tk_runstate,
686                                 RPC_TASK_QUEUED, rpc_wait_bit_killable,
687                                 TASK_KILLABLE);
688                 if (status == -ERESTARTSYS) {
689                         /*
690                          * When a sync task receives a signal, it exits with
691                          * -ERESTARTSYS. In order to catch any callbacks that
692                          * clean up after sleeping on some queue, we don't
693                          * break the loop here, but go around once more.
694                          */
695                         dprintk("RPC: %5u got signal\n", task->tk_pid);
696                         task->tk_flags |= RPC_TASK_KILLED;
697                         rpc_exit(task, -ERESTARTSYS);
698                         rpc_wake_up_task(task);
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  */
719 void rpc_execute(struct rpc_task *task)
720 {
721         rpc_set_active(task);
722         rpc_set_running(task);
723         __rpc_execute(task);
724 }
725
726 static void rpc_async_schedule(struct work_struct *work)
727 {
728         __rpc_execute(container_of(work, struct rpc_task, u.tk_work));
729 }
730
731 /**
732  * rpc_malloc - allocate an RPC buffer
733  * @task: RPC task that will use this buffer
734  * @size: requested byte size
735  *
736  * To prevent rpciod from hanging, this allocator never sleeps,
737  * returning NULL if the request cannot be serviced immediately.
738  * The caller can arrange to sleep in a way that is safe for rpciod.
739  *
740  * Most requests are 'small' (under 2KiB) and can be serviced from a
741  * mempool, ensuring that NFS reads and writes can always proceed,
742  * and that there is good locality of reference for these buffers.
743  *
744  * In order to avoid memory starvation triggering more writebacks of
745  * NFS requests, we avoid using GFP_KERNEL.
746  */
747 void *rpc_malloc(struct rpc_task *task, size_t size)
748 {
749         struct rpc_buffer *buf;
750         gfp_t gfp = RPC_IS_SWAPPER(task) ? GFP_ATOMIC : GFP_NOWAIT;
751
752         size += sizeof(struct rpc_buffer);
753         if (size <= RPC_BUFFER_MAXSIZE)
754                 buf = mempool_alloc(rpc_buffer_mempool, gfp);
755         else
756                 buf = kmalloc(size, gfp);
757
758         if (!buf)
759                 return NULL;
760
761         buf->len = size;
762         dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
763                         task->tk_pid, size, buf);
764         return &buf->data;
765 }
766 EXPORT_SYMBOL_GPL(rpc_malloc);
767
768 /**
769  * rpc_free - free buffer allocated via rpc_malloc
770  * @buffer: buffer to free
771  *
772  */
773 void rpc_free(void *buffer)
774 {
775         size_t size;
776         struct rpc_buffer *buf;
777
778         if (!buffer)
779                 return;
780
781         buf = container_of(buffer, struct rpc_buffer, data);
782         size = buf->len;
783
784         dprintk("RPC:       freeing buffer of size %zu at %p\n",
785                         size, buf);
786
787         if (size <= RPC_BUFFER_MAXSIZE)
788                 mempool_free(buf, rpc_buffer_mempool);
789         else
790                 kfree(buf);
791 }
792 EXPORT_SYMBOL_GPL(rpc_free);
793
794 /*
795  * Creation and deletion of RPC task structures
796  */
797 static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *task_setup_data)
798 {
799         memset(task, 0, sizeof(*task));
800         atomic_set(&task->tk_count, 1);
801         task->tk_flags  = task_setup_data->flags;
802         task->tk_ops = task_setup_data->callback_ops;
803         task->tk_calldata = task_setup_data->callback_data;
804         INIT_LIST_HEAD(&task->tk_task);
805
806         /* Initialize retry counters */
807         task->tk_garb_retry = 2;
808         task->tk_cred_retry = 2;
809
810         task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW;
811         task->tk_owner = current->tgid;
812
813         /* Initialize workqueue for async tasks */
814         task->tk_workqueue = task_setup_data->workqueue;
815
816         task->tk_client = task_setup_data->rpc_client;
817         if (task->tk_client != NULL) {
818                 kref_get(&task->tk_client->cl_kref);
819                 if (task->tk_client->cl_softrtry)
820                         task->tk_flags |= RPC_TASK_SOFT;
821         }
822
823         if (task->tk_ops->rpc_call_prepare != NULL)
824                 task->tk_action = rpc_prepare_task;
825
826         if (task_setup_data->rpc_message != NULL) {
827                 task->tk_msg.rpc_proc = task_setup_data->rpc_message->rpc_proc;
828                 task->tk_msg.rpc_argp = task_setup_data->rpc_message->rpc_argp;
829                 task->tk_msg.rpc_resp = task_setup_data->rpc_message->rpc_resp;
830                 /* Bind the user cred */
831                 rpcauth_bindcred(task, task_setup_data->rpc_message->rpc_cred, task_setup_data->flags);
832                 if (task->tk_action == NULL)
833                         rpc_call_start(task);
834         }
835
836         /* starting timestamp */
837         task->tk_start = jiffies;
838
839         dprintk("RPC:       new task initialized, procpid %u\n",
840                                 task_pid_nr(current));
841 }
842
843 static struct rpc_task *
844 rpc_alloc_task(void)
845 {
846         return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
847 }
848
849 /*
850  * Create a new task for the specified client.
851  */
852 struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
853 {
854         struct rpc_task *task = setup_data->task;
855         unsigned short flags = 0;
856
857         if (task == NULL) {
858                 task = rpc_alloc_task();
859                 if (task == NULL)
860                         goto out;
861                 flags = RPC_TASK_DYNAMIC;
862         }
863
864         rpc_init_task(task, setup_data);
865
866         task->tk_flags |= flags;
867         dprintk("RPC:       allocated task %p\n", task);
868 out:
869         return task;
870 }
871
872 static void rpc_free_task(struct rpc_task *task)
873 {
874         const struct rpc_call_ops *tk_ops = task->tk_ops;
875         void *calldata = task->tk_calldata;
876
877         if (task->tk_flags & RPC_TASK_DYNAMIC) {
878                 dprintk("RPC: %5u freeing task\n", task->tk_pid);
879                 mempool_free(task, rpc_task_mempool);
880         }
881         rpc_release_calldata(tk_ops, calldata);
882 }
883
884 static void rpc_async_release(struct work_struct *work)
885 {
886         rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
887 }
888
889 void rpc_put_task(struct rpc_task *task)
890 {
891         if (!atomic_dec_and_test(&task->tk_count))
892                 return;
893         /* Release resources */
894         if (task->tk_rqstp)
895                 xprt_release(task);
896         if (task->tk_msg.rpc_cred)
897                 rpcauth_unbindcred(task);
898         if (task->tk_client) {
899                 rpc_release_client(task->tk_client);
900                 task->tk_client = NULL;
901         }
902         if (task->tk_workqueue != NULL) {
903                 INIT_WORK(&task->u.tk_work, rpc_async_release);
904                 queue_work(task->tk_workqueue, &task->u.tk_work);
905         } else
906                 rpc_free_task(task);
907 }
908 EXPORT_SYMBOL_GPL(rpc_put_task);
909
910 static void rpc_release_task(struct rpc_task *task)
911 {
912 #ifdef RPC_DEBUG
913         BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
914 #endif
915         dprintk("RPC: %5u release task\n", task->tk_pid);
916
917         if (!list_empty(&task->tk_task)) {
918                 struct rpc_clnt *clnt = task->tk_client;
919                 /* Remove from client task list */
920                 spin_lock(&clnt->cl_lock);
921                 list_del(&task->tk_task);
922                 spin_unlock(&clnt->cl_lock);
923         }
924         BUG_ON (RPC_IS_QUEUED(task));
925
926 #ifdef RPC_DEBUG
927         task->tk_magic = 0;
928 #endif
929         /* Wake up anyone who is waiting for task completion */
930         rpc_mark_complete_task(task);
931
932         rpc_put_task(task);
933 }
934
935 /*
936  * Kill all tasks for the given client.
937  * XXX: kill their descendants as well?
938  */
939 void rpc_killall_tasks(struct rpc_clnt *clnt)
940 {
941         struct rpc_task *rovr;
942
943
944         if (list_empty(&clnt->cl_tasks))
945                 return;
946         dprintk("RPC:       killing all tasks for client %p\n", clnt);
947         /*
948          * Spin lock all_tasks to prevent changes...
949          */
950         spin_lock(&clnt->cl_lock);
951         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
952                 if (! RPC_IS_ACTIVATED(rovr))
953                         continue;
954                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
955                         rovr->tk_flags |= RPC_TASK_KILLED;
956                         rpc_exit(rovr, -EIO);
957                         rpc_wake_up_task(rovr);
958                 }
959         }
960         spin_unlock(&clnt->cl_lock);
961 }
962 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
963
964 int rpciod_up(void)
965 {
966         return try_module_get(THIS_MODULE) ? 0 : -EINVAL;
967 }
968
969 void rpciod_down(void)
970 {
971         module_put(THIS_MODULE);
972 }
973
974 /*
975  * Start up the rpciod workqueue.
976  */
977 static int rpciod_start(void)
978 {
979         struct workqueue_struct *wq;
980
981         /*
982          * Create the rpciod thread and wait for it to start.
983          */
984         dprintk("RPC:       creating workqueue rpciod\n");
985         wq = create_workqueue("rpciod");
986         rpciod_workqueue = wq;
987         return rpciod_workqueue != NULL;
988 }
989
990 static void rpciod_stop(void)
991 {
992         struct workqueue_struct *wq = NULL;
993
994         if (rpciod_workqueue == NULL)
995                 return;
996         dprintk("RPC:       destroying workqueue rpciod\n");
997
998         wq = rpciod_workqueue;
999         rpciod_workqueue = NULL;
1000         destroy_workqueue(wq);
1001 }
1002
1003 void
1004 rpc_destroy_mempool(void)
1005 {
1006         rpciod_stop();
1007         if (rpc_buffer_mempool)
1008                 mempool_destroy(rpc_buffer_mempool);
1009         if (rpc_task_mempool)
1010                 mempool_destroy(rpc_task_mempool);
1011         if (rpc_task_slabp)
1012                 kmem_cache_destroy(rpc_task_slabp);
1013         if (rpc_buffer_slabp)
1014                 kmem_cache_destroy(rpc_buffer_slabp);
1015         rpc_destroy_wait_queue(&delay_queue);
1016 }
1017
1018 int
1019 rpc_init_mempool(void)
1020 {
1021         /*
1022          * The following is not strictly a mempool initialisation,
1023          * but there is no harm in doing it here
1024          */
1025         rpc_init_wait_queue(&delay_queue, "delayq");
1026         if (!rpciod_start())
1027                 goto err_nomem;
1028
1029         rpc_task_slabp = kmem_cache_create("rpc_tasks",
1030                                              sizeof(struct rpc_task),
1031                                              0, SLAB_HWCACHE_ALIGN,
1032                                              NULL);
1033         if (!rpc_task_slabp)
1034                 goto err_nomem;
1035         rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1036                                              RPC_BUFFER_MAXSIZE,
1037                                              0, SLAB_HWCACHE_ALIGN,
1038                                              NULL);
1039         if (!rpc_buffer_slabp)
1040                 goto err_nomem;
1041         rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
1042                                                     rpc_task_slabp);
1043         if (!rpc_task_mempool)
1044                 goto err_nomem;
1045         rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
1046                                                       rpc_buffer_slabp);
1047         if (!rpc_buffer_mempool)
1048                 goto err_nomem;
1049         return 0;
1050 err_nomem:
1051         rpc_destroy_mempool();
1052         return -ENOMEM;
1053 }