[RPC]: fix sparse gfp nocast warnings
[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/smp_lock.h>
20 #include <linux/spinlock.h>
21
22 #include <linux/sunrpc/clnt.h>
23 #include <linux/sunrpc/xprt.h>
24
25 #ifdef RPC_DEBUG
26 #define RPCDBG_FACILITY         RPCDBG_SCHED
27 #define RPC_TASK_MAGIC_ID       0xf00baa
28 static 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)
37 static kmem_cache_t     *rpc_task_slabp __read_mostly;
38 static kmem_cache_t     *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_default_timer(struct rpc_task *task);
43 static void                     rpciod_killall(void);
44 static void                     rpc_free(struct rpc_task *task);
45
46 static void                     rpc_async_schedule(void *);
47
48 /*
49  * RPC tasks that create another task (e.g. for contacting the portmapper)
50  * will wait on this queue for their child's completion
51  */
52 static RPC_WAITQ(childq, "childq");
53
54 /*
55  * RPC tasks sit here while waiting for conditions to improve.
56  */
57 static RPC_WAITQ(delay_queue, "delayq");
58
59 /*
60  * All RPC tasks are linked into this list
61  */
62 static LIST_HEAD(all_tasks);
63
64 /*
65  * rpciod-related stuff
66  */
67 static DECLARE_MUTEX(rpciod_sema);
68 static unsigned int             rpciod_users;
69 static struct workqueue_struct *rpciod_workqueue;
70
71 /*
72  * Spinlock for other critical sections of code.
73  */
74 static DEFINE_SPINLOCK(rpc_sched_lock);
75
76 /*
77  * Disable the timer for a given RPC task. Should be called with
78  * queue->lock and bh_disabled in order to avoid races within
79  * rpc_run_timer().
80  */
81 static inline void
82 __rpc_disable_timer(struct rpc_task *task)
83 {
84         dprintk("RPC: %4d disabling timer\n", task->tk_pid);
85         task->tk_timeout_fn = NULL;
86         task->tk_timeout = 0;
87 }
88
89 /*
90  * Run a timeout function.
91  * We use the callback in order to allow __rpc_wake_up_task()
92  * and friends to disable the timer synchronously on SMP systems
93  * without calling del_timer_sync(). The latter could cause a
94  * deadlock if called while we're holding spinlocks...
95  */
96 static void rpc_run_timer(struct rpc_task *task)
97 {
98         void (*callback)(struct rpc_task *);
99
100         callback = task->tk_timeout_fn;
101         task->tk_timeout_fn = NULL;
102         if (callback && RPC_IS_QUEUED(task)) {
103                 dprintk("RPC: %4d running timer\n", task->tk_pid);
104                 callback(task);
105         }
106         smp_mb__before_clear_bit();
107         clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate);
108         smp_mb__after_clear_bit();
109 }
110
111 /*
112  * Set up a timer for the current task.
113  */
114 static inline void
115 __rpc_add_timer(struct rpc_task *task, rpc_action timer)
116 {
117         if (!task->tk_timeout)
118                 return;
119
120         dprintk("RPC: %4d setting alarm for %lu ms\n",
121                         task->tk_pid, task->tk_timeout * 1000 / HZ);
122
123         if (timer)
124                 task->tk_timeout_fn = timer;
125         else
126                 task->tk_timeout_fn = __rpc_default_timer;
127         set_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate);
128         mod_timer(&task->tk_timer, jiffies + task->tk_timeout);
129 }
130
131 /*
132  * Delete any timer for the current task. Because we use del_timer_sync(),
133  * this function should never be called while holding queue->lock.
134  */
135 static void
136 rpc_delete_timer(struct rpc_task *task)
137 {
138         if (RPC_IS_QUEUED(task))
139                 return;
140         if (test_and_clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate)) {
141                 del_singleshot_timer_sync(&task->tk_timer);
142                 dprintk("RPC: %4d deleting timer\n", task->tk_pid);
143         }
144 }
145
146 /*
147  * Add new request to a priority queue.
148  */
149 static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue, struct rpc_task *task)
150 {
151         struct list_head *q;
152         struct rpc_task *t;
153
154         INIT_LIST_HEAD(&task->u.tk_wait.links);
155         q = &queue->tasks[task->tk_priority];
156         if (unlikely(task->tk_priority > queue->maxpriority))
157                 q = &queue->tasks[queue->maxpriority];
158         list_for_each_entry(t, q, u.tk_wait.list) {
159                 if (t->tk_cookie == task->tk_cookie) {
160                         list_add_tail(&task->u.tk_wait.list, &t->u.tk_wait.links);
161                         return;
162                 }
163         }
164         list_add_tail(&task->u.tk_wait.list, q);
165 }
166
167 /*
168  * Add new request to wait queue.
169  *
170  * Swapper tasks always get inserted at the head of the queue.
171  * This should avoid many nasty memory deadlocks and hopefully
172  * improve overall performance.
173  * Everyone else gets appended to the queue to ensure proper FIFO behavior.
174  */
175 static void __rpc_add_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
176 {
177         BUG_ON (RPC_IS_QUEUED(task));
178
179         if (RPC_IS_PRIORITY(queue))
180                 __rpc_add_wait_queue_priority(queue, task);
181         else if (RPC_IS_SWAPPER(task))
182                 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
183         else
184                 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
185         task->u.tk_wait.rpc_waitq = queue;
186         rpc_set_queued(task);
187
188         dprintk("RPC: %4d added to queue %p \"%s\"\n",
189                                 task->tk_pid, queue, rpc_qname(queue));
190 }
191
192 /*
193  * Remove request from a priority queue.
194  */
195 static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
196 {
197         struct rpc_task *t;
198
199         if (!list_empty(&task->u.tk_wait.links)) {
200                 t = list_entry(task->u.tk_wait.links.next, struct rpc_task, u.tk_wait.list);
201                 list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);
202                 list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);
203         }
204         list_del(&task->u.tk_wait.list);
205 }
206
207 /*
208  * Remove request from queue.
209  * Note: must be called with spin lock held.
210  */
211 static void __rpc_remove_wait_queue(struct rpc_task *task)
212 {
213         struct rpc_wait_queue *queue;
214         queue = task->u.tk_wait.rpc_waitq;
215
216         if (RPC_IS_PRIORITY(queue))
217                 __rpc_remove_wait_queue_priority(task);
218         else
219                 list_del(&task->u.tk_wait.list);
220         dprintk("RPC: %4d removed from queue %p \"%s\"\n",
221                                 task->tk_pid, queue, rpc_qname(queue));
222 }
223
224 static inline void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
225 {
226         queue->priority = priority;
227         queue->count = 1 << (priority * 2);
228 }
229
230 static inline void rpc_set_waitqueue_cookie(struct rpc_wait_queue *queue, unsigned long cookie)
231 {
232         queue->cookie = cookie;
233         queue->nr = RPC_BATCH_COUNT;
234 }
235
236 static inline void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
237 {
238         rpc_set_waitqueue_priority(queue, queue->maxpriority);
239         rpc_set_waitqueue_cookie(queue, 0);
240 }
241
242 static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, int maxprio)
243 {
244         int i;
245
246         spin_lock_init(&queue->lock);
247         for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
248                 INIT_LIST_HEAD(&queue->tasks[i]);
249         queue->maxpriority = maxprio;
250         rpc_reset_waitqueue_priority(queue);
251 #ifdef RPC_DEBUG
252         queue->name = qname;
253 #endif
254 }
255
256 void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
257 {
258         __rpc_init_priority_wait_queue(queue, qname, RPC_PRIORITY_HIGH);
259 }
260
261 void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
262 {
263         __rpc_init_priority_wait_queue(queue, qname, 0);
264 }
265 EXPORT_SYMBOL(rpc_init_wait_queue);
266
267 /*
268  * Make an RPC task runnable.
269  *
270  * Note: If the task is ASYNC, this must be called with 
271  * the spinlock held to protect the wait queue operation.
272  */
273 static void rpc_make_runnable(struct rpc_task *task)
274 {
275         int do_ret;
276
277         BUG_ON(task->tk_timeout_fn);
278         do_ret = rpc_test_and_set_running(task);
279         rpc_clear_queued(task);
280         if (do_ret)
281                 return;
282         if (RPC_IS_ASYNC(task)) {
283                 int status;
284
285                 INIT_WORK(&task->u.tk_work, rpc_async_schedule, (void *)task);
286                 status = queue_work(task->tk_workqueue, &task->u.tk_work);
287                 if (status < 0) {
288                         printk(KERN_WARNING "RPC: failed to add task to queue: error: %d!\n", status);
289                         task->tk_status = status;
290                         return;
291                 }
292         } else
293                 wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
294 }
295
296 /*
297  * Place a newly initialized task on the workqueue.
298  */
299 static inline void
300 rpc_schedule_run(struct rpc_task *task)
301 {
302         /* Don't run a child twice! */
303         if (RPC_IS_ACTIVATED(task))
304                 return;
305         task->tk_active = 1;
306         rpc_make_runnable(task);
307 }
308
309 /*
310  * Prepare for sleeping on a wait queue.
311  * By always appending tasks to the list we ensure FIFO behavior.
312  * NB: An RPC task will only receive interrupt-driven events as long
313  * as it's on a wait queue.
314  */
315 static void __rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
316                         rpc_action action, rpc_action timer)
317 {
318         dprintk("RPC: %4d sleep_on(queue \"%s\" time %ld)\n", task->tk_pid,
319                                 rpc_qname(q), jiffies);
320
321         if (!RPC_IS_ASYNC(task) && !RPC_IS_ACTIVATED(task)) {
322                 printk(KERN_ERR "RPC: Inactive synchronous task put to sleep!\n");
323                 return;
324         }
325
326         /* Mark the task as being activated if so needed */
327         if (!RPC_IS_ACTIVATED(task))
328                 task->tk_active = 1;
329
330         __rpc_add_wait_queue(q, task);
331
332         BUG_ON(task->tk_callback != NULL);
333         task->tk_callback = action;
334         __rpc_add_timer(task, timer);
335 }
336
337 void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
338                                 rpc_action action, rpc_action timer)
339 {
340         /*
341          * Protect the queue operations.
342          */
343         spin_lock_bh(&q->lock);
344         __rpc_sleep_on(q, task, action, timer);
345         spin_unlock_bh(&q->lock);
346 }
347
348 /**
349  * __rpc_do_wake_up_task - wake up a single rpc_task
350  * @task: task to be woken up
351  *
352  * Caller must hold queue->lock, and have cleared the task queued flag.
353  */
354 static void __rpc_do_wake_up_task(struct rpc_task *task)
355 {
356         dprintk("RPC: %4d __rpc_wake_up_task (now %ld)\n", task->tk_pid, jiffies);
357
358 #ifdef RPC_DEBUG
359         BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
360 #endif
361         /* Has the task been executed yet? If not, we cannot wake it up! */
362         if (!RPC_IS_ACTIVATED(task)) {
363                 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
364                 return;
365         }
366
367         __rpc_disable_timer(task);
368         __rpc_remove_wait_queue(task);
369
370         rpc_make_runnable(task);
371
372         dprintk("RPC:      __rpc_wake_up_task done\n");
373 }
374
375 /*
376  * Wake up the specified task
377  */
378 static void __rpc_wake_up_task(struct rpc_task *task)
379 {
380         if (rpc_start_wakeup(task)) {
381                 if (RPC_IS_QUEUED(task))
382                         __rpc_do_wake_up_task(task);
383                 rpc_finish_wakeup(task);
384         }
385 }
386
387 /*
388  * Default timeout handler if none specified by user
389  */
390 static void
391 __rpc_default_timer(struct rpc_task *task)
392 {
393         dprintk("RPC: %d timeout (default timer)\n", task->tk_pid);
394         task->tk_status = -ETIMEDOUT;
395         rpc_wake_up_task(task);
396 }
397
398 /*
399  * Wake up the specified task
400  */
401 void rpc_wake_up_task(struct rpc_task *task)
402 {
403         if (rpc_start_wakeup(task)) {
404                 if (RPC_IS_QUEUED(task)) {
405                         struct rpc_wait_queue *queue = task->u.tk_wait.rpc_waitq;
406
407                         spin_lock_bh(&queue->lock);
408                         __rpc_do_wake_up_task(task);
409                         spin_unlock_bh(&queue->lock);
410                 }
411                 rpc_finish_wakeup(task);
412         }
413 }
414
415 /*
416  * Wake up the next task on a priority queue.
417  */
418 static struct rpc_task * __rpc_wake_up_next_priority(struct rpc_wait_queue *queue)
419 {
420         struct list_head *q;
421         struct rpc_task *task;
422
423         /*
424          * Service a batch of tasks from a single cookie.
425          */
426         q = &queue->tasks[queue->priority];
427         if (!list_empty(q)) {
428                 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
429                 if (queue->cookie == task->tk_cookie) {
430                         if (--queue->nr)
431                                 goto out;
432                         list_move_tail(&task->u.tk_wait.list, q);
433                 }
434                 /*
435                  * Check if we need to switch queues.
436                  */
437                 if (--queue->count)
438                         goto new_cookie;
439         }
440
441         /*
442          * Service the next queue.
443          */
444         do {
445                 if (q == &queue->tasks[0])
446                         q = &queue->tasks[queue->maxpriority];
447                 else
448                         q = q - 1;
449                 if (!list_empty(q)) {
450                         task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
451                         goto new_queue;
452                 }
453         } while (q != &queue->tasks[queue->priority]);
454
455         rpc_reset_waitqueue_priority(queue);
456         return NULL;
457
458 new_queue:
459         rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
460 new_cookie:
461         rpc_set_waitqueue_cookie(queue, task->tk_cookie);
462 out:
463         __rpc_wake_up_task(task);
464         return task;
465 }
466
467 /*
468  * Wake up the next task on the wait queue.
469  */
470 struct rpc_task * rpc_wake_up_next(struct rpc_wait_queue *queue)
471 {
472         struct rpc_task *task = NULL;
473
474         dprintk("RPC:      wake_up_next(%p \"%s\")\n", queue, rpc_qname(queue));
475         spin_lock_bh(&queue->lock);
476         if (RPC_IS_PRIORITY(queue))
477                 task = __rpc_wake_up_next_priority(queue);
478         else {
479                 task_for_first(task, &queue->tasks[0])
480                         __rpc_wake_up_task(task);
481         }
482         spin_unlock_bh(&queue->lock);
483
484         return task;
485 }
486
487 /**
488  * rpc_wake_up - wake up all rpc_tasks
489  * @queue: rpc_wait_queue on which the tasks are sleeping
490  *
491  * Grabs queue->lock
492  */
493 void rpc_wake_up(struct rpc_wait_queue *queue)
494 {
495         struct rpc_task *task;
496
497         struct list_head *head;
498         spin_lock_bh(&queue->lock);
499         head = &queue->tasks[queue->maxpriority];
500         for (;;) {
501                 while (!list_empty(head)) {
502                         task = list_entry(head->next, struct rpc_task, u.tk_wait.list);
503                         __rpc_wake_up_task(task);
504                 }
505                 if (head == &queue->tasks[0])
506                         break;
507                 head--;
508         }
509         spin_unlock_bh(&queue->lock);
510 }
511
512 /**
513  * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
514  * @queue: rpc_wait_queue on which the tasks are sleeping
515  * @status: status value to set
516  *
517  * Grabs queue->lock
518  */
519 void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
520 {
521         struct list_head *head;
522         struct rpc_task *task;
523
524         spin_lock_bh(&queue->lock);
525         head = &queue->tasks[queue->maxpriority];
526         for (;;) {
527                 while (!list_empty(head)) {
528                         task = list_entry(head->next, struct rpc_task, u.tk_wait.list);
529                         task->tk_status = status;
530                         __rpc_wake_up_task(task);
531                 }
532                 if (head == &queue->tasks[0])
533                         break;
534                 head--;
535         }
536         spin_unlock_bh(&queue->lock);
537 }
538
539 /*
540  * Run a task at a later time
541  */
542 static void     __rpc_atrun(struct rpc_task *);
543 void
544 rpc_delay(struct rpc_task *task, unsigned long delay)
545 {
546         task->tk_timeout = delay;
547         rpc_sleep_on(&delay_queue, task, NULL, __rpc_atrun);
548 }
549
550 static void
551 __rpc_atrun(struct rpc_task *task)
552 {
553         task->tk_status = 0;
554         rpc_wake_up_task(task);
555 }
556
557 /*
558  * Helper that calls task->tk_exit if it exists and then returns
559  * true if we should exit __rpc_execute.
560  */
561 static inline int __rpc_do_exit(struct rpc_task *task)
562 {
563         if (task->tk_exit != NULL) {
564                 lock_kernel();
565                 task->tk_exit(task);
566                 unlock_kernel();
567                 /* If tk_action is non-null, we should restart the call */
568                 if (task->tk_action != NULL) {
569                         if (!RPC_ASSASSINATED(task)) {
570                                 /* Release RPC slot and buffer memory */
571                                 xprt_release(task);
572                                 rpc_free(task);
573                                 return 0;
574                         }
575                         printk(KERN_ERR "RPC: dead task tried to walk away.\n");
576                 }
577         }
578         return 1;
579 }
580
581 static int rpc_wait_bit_interruptible(void *word)
582 {
583         if (signal_pending(current))
584                 return -ERESTARTSYS;
585         schedule();
586         return 0;
587 }
588
589 /*
590  * This is the RPC `scheduler' (or rather, the finite state machine).
591  */
592 static int __rpc_execute(struct rpc_task *task)
593 {
594         int             status = 0;
595
596         dprintk("RPC: %4d rpc_execute flgs %x\n",
597                                 task->tk_pid, task->tk_flags);
598
599         BUG_ON(RPC_IS_QUEUED(task));
600
601         for (;;) {
602                 /*
603                  * Garbage collection of pending timers...
604                  */
605                 rpc_delete_timer(task);
606
607                 /*
608                  * Execute any pending callback.
609                  */
610                 if (RPC_DO_CALLBACK(task)) {
611                         /* Define a callback save pointer */
612                         void (*save_callback)(struct rpc_task *);
613         
614                         /* 
615                          * If a callback exists, save it, reset it,
616                          * call it.
617                          * The save is needed to stop from resetting
618                          * another callback set within the callback handler
619                          * - Dave
620                          */
621                         save_callback=task->tk_callback;
622                         task->tk_callback=NULL;
623                         lock_kernel();
624                         save_callback(task);
625                         unlock_kernel();
626                 }
627
628                 /*
629                  * Perform the next FSM step.
630                  * tk_action may be NULL when the task has been killed
631                  * by someone else.
632                  */
633                 if (!RPC_IS_QUEUED(task)) {
634                         if (task->tk_action != NULL) {
635                                 lock_kernel();
636                                 task->tk_action(task);
637                                 unlock_kernel();
638                         } else if (__rpc_do_exit(task))
639                                 break;
640                 }
641
642                 /*
643                  * Lockless check for whether task is sleeping or not.
644                  */
645                 if (!RPC_IS_QUEUED(task))
646                         continue;
647                 rpc_clear_running(task);
648                 if (RPC_IS_ASYNC(task)) {
649                         /* Careful! we may have raced... */
650                         if (RPC_IS_QUEUED(task))
651                                 return 0;
652                         if (rpc_test_and_set_running(task))
653                                 return 0;
654                         continue;
655                 }
656
657                 /* sync task: sleep here */
658                 dprintk("RPC: %4d sync task going to sleep\n", task->tk_pid);
659                 /* Note: Caller should be using rpc_clnt_sigmask() */
660                 status = out_of_line_wait_on_bit(&task->tk_runstate,
661                                 RPC_TASK_QUEUED, rpc_wait_bit_interruptible,
662                                 TASK_INTERRUPTIBLE);
663                 if (status == -ERESTARTSYS) {
664                         /*
665                          * When a sync task receives a signal, it exits with
666                          * -ERESTARTSYS. In order to catch any callbacks that
667                          * clean up after sleeping on some queue, we don't
668                          * break the loop here, but go around once more.
669                          */
670                         dprintk("RPC: %4d got signal\n", task->tk_pid);
671                         task->tk_flags |= RPC_TASK_KILLED;
672                         rpc_exit(task, -ERESTARTSYS);
673                         rpc_wake_up_task(task);
674                 }
675                 rpc_set_running(task);
676                 dprintk("RPC: %4d sync task resuming\n", task->tk_pid);
677         }
678
679         dprintk("RPC: %4d exit() = %d\n", task->tk_pid, task->tk_status);
680         status = task->tk_status;
681
682         /* Release all resources associated with the task */
683         rpc_release_task(task);
684         return status;
685 }
686
687 /*
688  * User-visible entry point to the scheduler.
689  *
690  * This may be called recursively if e.g. an async NFS task updates
691  * the attributes and finds that dirty pages must be flushed.
692  * NOTE: Upon exit of this function the task is guaranteed to be
693  *       released. In particular note that tk_release() will have
694  *       been called, so your task memory may have been freed.
695  */
696 int
697 rpc_execute(struct rpc_task *task)
698 {
699         BUG_ON(task->tk_active);
700
701         task->tk_active = 1;
702         rpc_set_running(task);
703         return __rpc_execute(task);
704 }
705
706 static void rpc_async_schedule(void *arg)
707 {
708         __rpc_execute((struct rpc_task *)arg);
709 }
710
711 /*
712  * Allocate memory for RPC purposes.
713  *
714  * We try to ensure that some NFS reads and writes can always proceed
715  * by using a mempool when allocating 'small' buffers.
716  * In order to avoid memory starvation triggering more writebacks of
717  * NFS requests, we use GFP_NOFS rather than GFP_KERNEL.
718  */
719 void *
720 rpc_malloc(struct rpc_task *task, size_t size)
721 {
722         unsigned int __nocast   gfp;
723
724         if (task->tk_flags & RPC_TASK_SWAPPER)
725                 gfp = GFP_ATOMIC;
726         else
727                 gfp = GFP_NOFS;
728
729         if (size > RPC_BUFFER_MAXSIZE) {
730                 task->tk_buffer =  kmalloc(size, gfp);
731                 if (task->tk_buffer)
732                         task->tk_bufsize = size;
733         } else {
734                 task->tk_buffer =  mempool_alloc(rpc_buffer_mempool, gfp);
735                 if (task->tk_buffer)
736                         task->tk_bufsize = RPC_BUFFER_MAXSIZE;
737         }
738         return task->tk_buffer;
739 }
740
741 static void
742 rpc_free(struct rpc_task *task)
743 {
744         if (task->tk_buffer) {
745                 if (task->tk_bufsize == RPC_BUFFER_MAXSIZE)
746                         mempool_free(task->tk_buffer, rpc_buffer_mempool);
747                 else
748                         kfree(task->tk_buffer);
749                 task->tk_buffer = NULL;
750                 task->tk_bufsize = 0;
751         }
752 }
753
754 /*
755  * Creation and deletion of RPC task structures
756  */
757 void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, rpc_action callback, int flags)
758 {
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;
763         task->tk_client = clnt;
764         task->tk_flags  = flags;
765         task->tk_exit   = callback;
766
767         /* Initialize retry counters */
768         task->tk_garb_retry = 2;
769         task->tk_cred_retry = 2;
770
771         task->tk_priority = RPC_PRIORITY_NORMAL;
772         task->tk_cookie = (unsigned long)current;
773
774         /* Initialize workqueue for async tasks */
775         task->tk_workqueue = rpciod_workqueue;
776
777         if (clnt) {
778                 atomic_inc(&clnt->cl_users);
779                 if (clnt->cl_softrtry)
780                         task->tk_flags |= RPC_TASK_SOFT;
781                 if (!clnt->cl_intr)
782                         task->tk_flags |= RPC_TASK_NOINTR;
783         }
784
785 #ifdef RPC_DEBUG
786         task->tk_magic = RPC_TASK_MAGIC_ID;
787         task->tk_pid = rpc_task_id++;
788 #endif
789         /* Add to global list of all tasks */
790         spin_lock(&rpc_sched_lock);
791         list_add_tail(&task->tk_task, &all_tasks);
792         spin_unlock(&rpc_sched_lock);
793
794         dprintk("RPC: %4d new task procpid %d\n", task->tk_pid,
795                                 current->pid);
796 }
797
798 static struct rpc_task *
799 rpc_alloc_task(void)
800 {
801         return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
802 }
803
804 static void
805 rpc_default_free_task(struct rpc_task *task)
806 {
807         dprintk("RPC: %4d freeing task\n", task->tk_pid);
808         mempool_free(task, rpc_task_mempool);
809 }
810
811 /*
812  * Create a new task for the specified client.  We have to
813  * clean up after an allocation failure, as the client may
814  * have specified "oneshot".
815  */
816 struct rpc_task *
817 rpc_new_task(struct rpc_clnt *clnt, rpc_action callback, int flags)
818 {
819         struct rpc_task *task;
820
821         task = rpc_alloc_task();
822         if (!task)
823                 goto cleanup;
824
825         rpc_init_task(task, clnt, callback, flags);
826
827         /* Replace tk_release */
828         task->tk_release = rpc_default_free_task;
829
830         dprintk("RPC: %4d allocated task\n", task->tk_pid);
831         task->tk_flags |= RPC_TASK_DYNAMIC;
832 out:
833         return task;
834
835 cleanup:
836         /* Check whether to release the client */
837         if (clnt) {
838                 printk("rpc_new_task: failed, users=%d, oneshot=%d\n",
839                         atomic_read(&clnt->cl_users), clnt->cl_oneshot);
840                 atomic_inc(&clnt->cl_users); /* pretend we were used ... */
841                 rpc_release_client(clnt);
842         }
843         goto out;
844 }
845
846 void rpc_release_task(struct rpc_task *task)
847 {
848         dprintk("RPC: %4d release task\n", task->tk_pid);
849
850 #ifdef RPC_DEBUG
851         BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
852 #endif
853
854         /* Remove from global task list */
855         spin_lock(&rpc_sched_lock);
856         list_del(&task->tk_task);
857         spin_unlock(&rpc_sched_lock);
858
859         BUG_ON (RPC_IS_QUEUED(task));
860         task->tk_active = 0;
861
862         /* Synchronously delete any running timer */
863         rpc_delete_timer(task);
864
865         /* Release resources */
866         if (task->tk_rqstp)
867                 xprt_release(task);
868         if (task->tk_msg.rpc_cred)
869                 rpcauth_unbindcred(task);
870         rpc_free(task);
871         if (task->tk_client) {
872                 rpc_release_client(task->tk_client);
873                 task->tk_client = NULL;
874         }
875
876 #ifdef RPC_DEBUG
877         task->tk_magic = 0;
878 #endif
879         if (task->tk_release)
880                 task->tk_release(task);
881 }
882
883 /**
884  * rpc_find_parent - find the parent of a child task.
885  * @child: child task
886  *
887  * Checks that the parent task is still sleeping on the
888  * queue 'childq'. If so returns a pointer to the parent.
889  * Upon failure returns NULL.
890  *
891  * Caller must hold childq.lock
892  */
893 static inline struct rpc_task *rpc_find_parent(struct rpc_task *child)
894 {
895         struct rpc_task *task, *parent;
896         struct list_head *le;
897
898         parent = (struct rpc_task *) child->tk_calldata;
899         task_for_each(task, le, &childq.tasks[0])
900                 if (task == parent)
901                         return parent;
902
903         return NULL;
904 }
905
906 static void rpc_child_exit(struct rpc_task *child)
907 {
908         struct rpc_task *parent;
909
910         spin_lock_bh(&childq.lock);
911         if ((parent = rpc_find_parent(child)) != NULL) {
912                 parent->tk_status = child->tk_status;
913                 __rpc_wake_up_task(parent);
914         }
915         spin_unlock_bh(&childq.lock);
916 }
917
918 /*
919  * Note: rpc_new_task releases the client after a failure.
920  */
921 struct rpc_task *
922 rpc_new_child(struct rpc_clnt *clnt, struct rpc_task *parent)
923 {
924         struct rpc_task *task;
925
926         task = rpc_new_task(clnt, NULL, RPC_TASK_ASYNC | RPC_TASK_CHILD);
927         if (!task)
928                 goto fail;
929         task->tk_exit = rpc_child_exit;
930         task->tk_calldata = parent;
931         return task;
932
933 fail:
934         parent->tk_status = -ENOMEM;
935         return NULL;
936 }
937
938 void rpc_run_child(struct rpc_task *task, struct rpc_task *child, rpc_action func)
939 {
940         spin_lock_bh(&childq.lock);
941         /* N.B. Is it possible for the child to have already finished? */
942         __rpc_sleep_on(&childq, task, func, NULL);
943         rpc_schedule_run(child);
944         spin_unlock_bh(&childq.lock);
945 }
946
947 /*
948  * Kill all tasks for the given client.
949  * XXX: kill their descendants as well?
950  */
951 void rpc_killall_tasks(struct rpc_clnt *clnt)
952 {
953         struct rpc_task *rovr;
954         struct list_head *le;
955
956         dprintk("RPC:      killing all tasks for client %p\n", clnt);
957
958         /*
959          * Spin lock all_tasks to prevent changes...
960          */
961         spin_lock(&rpc_sched_lock);
962         alltask_for_each(rovr, le, &all_tasks) {
963                 if (! RPC_IS_ACTIVATED(rovr))
964                         continue;
965                 if (!clnt || rovr->tk_client == clnt) {
966                         rovr->tk_flags |= RPC_TASK_KILLED;
967                         rpc_exit(rovr, -EIO);
968                         rpc_wake_up_task(rovr);
969                 }
970         }
971         spin_unlock(&rpc_sched_lock);
972 }
973
974 static DECLARE_MUTEX_LOCKED(rpciod_running);
975
976 static void rpciod_killall(void)
977 {
978         unsigned long flags;
979
980         while (!list_empty(&all_tasks)) {
981                 clear_thread_flag(TIF_SIGPENDING);
982                 rpc_killall_tasks(NULL);
983                 flush_workqueue(rpciod_workqueue);
984                 if (!list_empty(&all_tasks)) {
985                         dprintk("rpciod_killall: waiting for tasks to exit\n");
986                         yield();
987                 }
988         }
989
990         spin_lock_irqsave(&current->sighand->siglock, flags);
991         recalc_sigpending();
992         spin_unlock_irqrestore(&current->sighand->siglock, flags);
993 }
994
995 /*
996  * Start up the rpciod process if it's not already running.
997  */
998 int
999 rpciod_up(void)
1000 {
1001         struct workqueue_struct *wq;
1002         int error = 0;
1003
1004         down(&rpciod_sema);
1005         dprintk("rpciod_up: users %d\n", rpciod_users);
1006         rpciod_users++;
1007         if (rpciod_workqueue)
1008                 goto out;
1009         /*
1010          * If there's no pid, we should be the first user.
1011          */
1012         if (rpciod_users > 1)
1013                 printk(KERN_WARNING "rpciod_up: no workqueue, %d users??\n", rpciod_users);
1014         /*
1015          * Create the rpciod thread and wait for it to start.
1016          */
1017         error = -ENOMEM;
1018         wq = create_workqueue("rpciod");
1019         if (wq == NULL) {
1020                 printk(KERN_WARNING "rpciod_up: create workqueue failed, error=%d\n", error);
1021                 rpciod_users--;
1022                 goto out;
1023         }
1024         rpciod_workqueue = wq;
1025         error = 0;
1026 out:
1027         up(&rpciod_sema);
1028         return error;
1029 }
1030
1031 void
1032 rpciod_down(void)
1033 {
1034         down(&rpciod_sema);
1035         dprintk("rpciod_down sema %d\n", rpciod_users);
1036         if (rpciod_users) {
1037                 if (--rpciod_users)
1038                         goto out;
1039         } else
1040                 printk(KERN_WARNING "rpciod_down: no users??\n");
1041
1042         if (!rpciod_workqueue) {
1043                 dprintk("rpciod_down: Nothing to do!\n");
1044                 goto out;
1045         }
1046         rpciod_killall();
1047
1048         destroy_workqueue(rpciod_workqueue);
1049         rpciod_workqueue = NULL;
1050  out:
1051         up(&rpciod_sema);
1052 }
1053
1054 #ifdef RPC_DEBUG
1055 void rpc_show_tasks(void)
1056 {
1057         struct list_head *le;
1058         struct rpc_task *t;
1059
1060         spin_lock(&rpc_sched_lock);
1061         if (list_empty(&all_tasks)) {
1062                 spin_unlock(&rpc_sched_lock);
1063                 return;
1064         }
1065         printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
1066                 "-rpcwait -action- --exit--\n");
1067         alltask_for_each(t, le, &all_tasks) {
1068                 const char *rpc_waitq = "none";
1069
1070                 if (RPC_IS_QUEUED(t))
1071                         rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
1072
1073                 printk("%05d %04d %04x %06d %8p %6d %8p %08ld %8s %8p %8p\n",
1074                         t->tk_pid,
1075                         (t->tk_msg.rpc_proc ? t->tk_msg.rpc_proc->p_proc : -1),
1076                         t->tk_flags, t->tk_status,
1077                         t->tk_client,
1078                         (t->tk_client ? t->tk_client->cl_prog : 0),
1079                         t->tk_rqstp, t->tk_timeout,
1080                         rpc_waitq,
1081                         t->tk_action, t->tk_exit);
1082         }
1083         spin_unlock(&rpc_sched_lock);
1084 }
1085 #endif
1086
1087 void
1088 rpc_destroy_mempool(void)
1089 {
1090         if (rpc_buffer_mempool)
1091                 mempool_destroy(rpc_buffer_mempool);
1092         if (rpc_task_mempool)
1093                 mempool_destroy(rpc_task_mempool);
1094         if (rpc_task_slabp && kmem_cache_destroy(rpc_task_slabp))
1095                 printk(KERN_INFO "rpc_task: not all structures were freed\n");
1096         if (rpc_buffer_slabp && kmem_cache_destroy(rpc_buffer_slabp))
1097                 printk(KERN_INFO "rpc_buffers: not all structures were freed\n");
1098 }
1099
1100 int
1101 rpc_init_mempool(void)
1102 {
1103         rpc_task_slabp = kmem_cache_create("rpc_tasks",
1104                                              sizeof(struct rpc_task),
1105                                              0, SLAB_HWCACHE_ALIGN,
1106                                              NULL, NULL);
1107         if (!rpc_task_slabp)
1108                 goto err_nomem;
1109         rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1110                                              RPC_BUFFER_MAXSIZE,
1111                                              0, SLAB_HWCACHE_ALIGN,
1112                                              NULL, NULL);
1113         if (!rpc_buffer_slabp)
1114                 goto err_nomem;
1115         rpc_task_mempool = mempool_create(RPC_TASK_POOLSIZE,
1116                                             mempool_alloc_slab,
1117                                             mempool_free_slab,
1118                                             rpc_task_slabp);
1119         if (!rpc_task_mempool)
1120                 goto err_nomem;
1121         rpc_buffer_mempool = mempool_create(RPC_BUFFER_POOLSIZE,
1122                                             mempool_alloc_slab,
1123                                             mempool_free_slab,
1124                                             rpc_buffer_slabp);
1125         if (!rpc_buffer_mempool)
1126                 goto err_nomem;
1127         return 0;
1128 err_nomem:
1129         rpc_destroy_mempool();
1130         return -ENOMEM;
1131 }