]>
Commit | Line | Data |
---|---|---|
1 | /* | |
2 | * linux/kernel/workqueue.c | |
3 | * | |
4 | * Generic mechanism for defining kernel helper threads for running | |
5 | * arbitrary tasks in process context. | |
6 | * | |
7 | * Started by Ingo Molnar, Copyright (C) 2002 | |
8 | * | |
9 | * Derived from the taskqueue/keventd code by: | |
10 | * | |
11 | * David Woodhouse <dwmw2@infradead.org> | |
12 | * Andrew Morton <andrewm@uow.edu.au> | |
13 | * Kai Petzke <wpp@marie.physik.tu-berlin.de> | |
14 | * Theodore Ts'o <tytso@mit.edu> | |
15 | * | |
16 | * Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>. | |
17 | */ | |
18 | ||
19 | #include <linux/module.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/sched.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/signal.h> | |
24 | #include <linux/completion.h> | |
25 | #include <linux/workqueue.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/cpu.h> | |
28 | #include <linux/notifier.h> | |
29 | #include <linux/kthread.h> | |
30 | #include <linux/hardirq.h> | |
31 | #include <linux/mempolicy.h> | |
32 | #include <linux/freezer.h> | |
33 | #include <linux/kallsyms.h> | |
34 | #include <linux/debug_locks.h> | |
35 | ||
36 | /* | |
37 | * The per-CPU workqueue (if single thread, we always use the first | |
38 | * possible cpu). | |
39 | */ | |
40 | struct cpu_workqueue_struct { | |
41 | ||
42 | spinlock_t lock; | |
43 | ||
44 | struct list_head worklist; | |
45 | wait_queue_head_t more_work; | |
46 | ||
47 | struct workqueue_struct *wq; | |
48 | struct task_struct *thread; | |
49 | struct work_struct *current_work; | |
50 | ||
51 | int run_depth; /* Detect run_workqueue() recursion depth */ | |
52 | } ____cacheline_aligned; | |
53 | ||
54 | /* | |
55 | * The externally visible workqueue abstraction is an array of | |
56 | * per-CPU workqueues: | |
57 | */ | |
58 | struct workqueue_struct { | |
59 | struct cpu_workqueue_struct *cpu_wq; | |
60 | const char *name; | |
61 | struct list_head list; /* Empty if single thread */ | |
62 | int freezeable; /* Freeze threads during suspend */ | |
63 | }; | |
64 | ||
65 | /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove | |
66 | threads to each one as cpus come/go. */ | |
67 | static DEFINE_MUTEX(workqueue_mutex); | |
68 | static LIST_HEAD(workqueues); | |
69 | ||
70 | static int singlethread_cpu; | |
71 | ||
72 | /* If it's single threaded, it isn't in the list of workqueues. */ | |
73 | static inline int is_single_threaded(struct workqueue_struct *wq) | |
74 | { | |
75 | return list_empty(&wq->list); | |
76 | } | |
77 | ||
78 | /* | |
79 | * Set the workqueue on which a work item is to be run | |
80 | * - Must *only* be called if the pending flag is set | |
81 | */ | |
82 | static inline void set_wq_data(struct work_struct *work, void *wq) | |
83 | { | |
84 | unsigned long new; | |
85 | ||
86 | BUG_ON(!work_pending(work)); | |
87 | ||
88 | new = (unsigned long) wq | (1UL << WORK_STRUCT_PENDING); | |
89 | new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); | |
90 | atomic_long_set(&work->data, new); | |
91 | } | |
92 | ||
93 | static inline void *get_wq_data(struct work_struct *work) | |
94 | { | |
95 | return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); | |
96 | } | |
97 | ||
98 | static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work) | |
99 | { | |
100 | int ret = 0; | |
101 | unsigned long flags; | |
102 | ||
103 | spin_lock_irqsave(&cwq->lock, flags); | |
104 | /* | |
105 | * We need to re-validate the work info after we've gotten | |
106 | * the cpu_workqueue lock. We can run the work now iff: | |
107 | * | |
108 | * - the wq_data still matches the cpu_workqueue_struct | |
109 | * - AND the work is still marked pending | |
110 | * - AND the work is still on a list (which will be this | |
111 | * workqueue_struct list) | |
112 | * | |
113 | * All these conditions are important, because we | |
114 | * need to protect against the work being run right | |
115 | * now on another CPU (all but the last one might be | |
116 | * true if it's currently running and has not been | |
117 | * released yet, for example). | |
118 | */ | |
119 | if (get_wq_data(work) == cwq | |
120 | && work_pending(work) | |
121 | && !list_empty(&work->entry)) { | |
122 | work_func_t f = work->func; | |
123 | cwq->current_work = work; | |
124 | list_del_init(&work->entry); | |
125 | spin_unlock_irqrestore(&cwq->lock, flags); | |
126 | ||
127 | if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work))) | |
128 | work_release(work); | |
129 | f(work); | |
130 | ||
131 | spin_lock_irqsave(&cwq->lock, flags); | |
132 | cwq->current_work = NULL; | |
133 | ret = 1; | |
134 | } | |
135 | spin_unlock_irqrestore(&cwq->lock, flags); | |
136 | return ret; | |
137 | } | |
138 | ||
139 | /** | |
140 | * run_scheduled_work - run scheduled work synchronously | |
141 | * @work: work to run | |
142 | * | |
143 | * This checks if the work was pending, and runs it | |
144 | * synchronously if so. It returns a boolean to indicate | |
145 | * whether it had any scheduled work to run or not. | |
146 | * | |
147 | * NOTE! This _only_ works for normal work_structs. You | |
148 | * CANNOT use this for delayed work, because the wq data | |
149 | * for delayed work will not point properly to the per- | |
150 | * CPU workqueue struct, but will change! | |
151 | */ | |
152 | int fastcall run_scheduled_work(struct work_struct *work) | |
153 | { | |
154 | for (;;) { | |
155 | struct cpu_workqueue_struct *cwq; | |
156 | ||
157 | if (!work_pending(work)) | |
158 | return 0; | |
159 | if (list_empty(&work->entry)) | |
160 | return 0; | |
161 | /* NOTE! This depends intimately on __queue_work! */ | |
162 | cwq = get_wq_data(work); | |
163 | if (!cwq) | |
164 | return 0; | |
165 | if (__run_work(cwq, work)) | |
166 | return 1; | |
167 | } | |
168 | } | |
169 | EXPORT_SYMBOL(run_scheduled_work); | |
170 | ||
171 | static void insert_work(struct cpu_workqueue_struct *cwq, | |
172 | struct work_struct *work, int tail) | |
173 | { | |
174 | set_wq_data(work, cwq); | |
175 | if (tail) | |
176 | list_add_tail(&work->entry, &cwq->worklist); | |
177 | else | |
178 | list_add(&work->entry, &cwq->worklist); | |
179 | wake_up(&cwq->more_work); | |
180 | } | |
181 | ||
182 | /* Preempt must be disabled. */ | |
183 | static void __queue_work(struct cpu_workqueue_struct *cwq, | |
184 | struct work_struct *work) | |
185 | { | |
186 | unsigned long flags; | |
187 | ||
188 | spin_lock_irqsave(&cwq->lock, flags); | |
189 | insert_work(cwq, work, 1); | |
190 | spin_unlock_irqrestore(&cwq->lock, flags); | |
191 | } | |
192 | ||
193 | /** | |
194 | * queue_work - queue work on a workqueue | |
195 | * @wq: workqueue to use | |
196 | * @work: work to queue | |
197 | * | |
198 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
199 | * | |
200 | * We queue the work to the CPU it was submitted, but there is no | |
201 | * guarantee that it will be processed by that CPU. | |
202 | */ | |
203 | int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) | |
204 | { | |
205 | int ret = 0, cpu = get_cpu(); | |
206 | ||
207 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | |
208 | if (unlikely(is_single_threaded(wq))) | |
209 | cpu = singlethread_cpu; | |
210 | BUG_ON(!list_empty(&work->entry)); | |
211 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); | |
212 | ret = 1; | |
213 | } | |
214 | put_cpu(); | |
215 | return ret; | |
216 | } | |
217 | EXPORT_SYMBOL_GPL(queue_work); | |
218 | ||
219 | void delayed_work_timer_fn(unsigned long __data) | |
220 | { | |
221 | struct delayed_work *dwork = (struct delayed_work *)__data; | |
222 | struct workqueue_struct *wq = get_wq_data(&dwork->work); | |
223 | int cpu = smp_processor_id(); | |
224 | ||
225 | if (unlikely(is_single_threaded(wq))) | |
226 | cpu = singlethread_cpu; | |
227 | ||
228 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), &dwork->work); | |
229 | } | |
230 | ||
231 | /** | |
232 | * queue_delayed_work - queue work on a workqueue after delay | |
233 | * @wq: workqueue to use | |
234 | * @dwork: delayable work to queue | |
235 | * @delay: number of jiffies to wait before queueing | |
236 | * | |
237 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
238 | */ | |
239 | int fastcall queue_delayed_work(struct workqueue_struct *wq, | |
240 | struct delayed_work *dwork, unsigned long delay) | |
241 | { | |
242 | int ret = 0; | |
243 | struct timer_list *timer = &dwork->timer; | |
244 | struct work_struct *work = &dwork->work; | |
245 | ||
246 | timer_stats_timer_set_start_info(timer); | |
247 | if (delay == 0) | |
248 | return queue_work(wq, work); | |
249 | ||
250 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | |
251 | BUG_ON(timer_pending(timer)); | |
252 | BUG_ON(!list_empty(&work->entry)); | |
253 | ||
254 | /* This stores wq for the moment, for the timer_fn */ | |
255 | set_wq_data(work, wq); | |
256 | timer->expires = jiffies + delay; | |
257 | timer->data = (unsigned long)dwork; | |
258 | timer->function = delayed_work_timer_fn; | |
259 | add_timer(timer); | |
260 | ret = 1; | |
261 | } | |
262 | return ret; | |
263 | } | |
264 | EXPORT_SYMBOL_GPL(queue_delayed_work); | |
265 | ||
266 | /** | |
267 | * queue_delayed_work_on - queue work on specific CPU after delay | |
268 | * @cpu: CPU number to execute work on | |
269 | * @wq: workqueue to use | |
270 | * @dwork: work to queue | |
271 | * @delay: number of jiffies to wait before queueing | |
272 | * | |
273 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
274 | */ | |
275 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, | |
276 | struct delayed_work *dwork, unsigned long delay) | |
277 | { | |
278 | int ret = 0; | |
279 | struct timer_list *timer = &dwork->timer; | |
280 | struct work_struct *work = &dwork->work; | |
281 | ||
282 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | |
283 | BUG_ON(timer_pending(timer)); | |
284 | BUG_ON(!list_empty(&work->entry)); | |
285 | ||
286 | /* This stores wq for the moment, for the timer_fn */ | |
287 | set_wq_data(work, wq); | |
288 | timer->expires = jiffies + delay; | |
289 | timer->data = (unsigned long)dwork; | |
290 | timer->function = delayed_work_timer_fn; | |
291 | add_timer_on(timer, cpu); | |
292 | ret = 1; | |
293 | } | |
294 | return ret; | |
295 | } | |
296 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); | |
297 | ||
298 | static void run_workqueue(struct cpu_workqueue_struct *cwq) | |
299 | { | |
300 | unsigned long flags; | |
301 | ||
302 | /* | |
303 | * Keep taking off work from the queue until | |
304 | * done. | |
305 | */ | |
306 | spin_lock_irqsave(&cwq->lock, flags); | |
307 | cwq->run_depth++; | |
308 | if (cwq->run_depth > 3) { | |
309 | /* morton gets to eat his hat */ | |
310 | printk("%s: recursion depth exceeded: %d\n", | |
311 | __FUNCTION__, cwq->run_depth); | |
312 | dump_stack(); | |
313 | } | |
314 | while (!list_empty(&cwq->worklist)) { | |
315 | struct work_struct *work = list_entry(cwq->worklist.next, | |
316 | struct work_struct, entry); | |
317 | work_func_t f = work->func; | |
318 | ||
319 | cwq->current_work = work; | |
320 | list_del_init(cwq->worklist.next); | |
321 | spin_unlock_irqrestore(&cwq->lock, flags); | |
322 | ||
323 | BUG_ON(get_wq_data(work) != cwq); | |
324 | if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work))) | |
325 | work_release(work); | |
326 | f(work); | |
327 | ||
328 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { | |
329 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
330 | "%s/0x%08x/%d\n", | |
331 | current->comm, preempt_count(), | |
332 | current->pid); | |
333 | printk(KERN_ERR " last function: "); | |
334 | print_symbol("%s\n", (unsigned long)f); | |
335 | debug_show_held_locks(current); | |
336 | dump_stack(); | |
337 | } | |
338 | ||
339 | spin_lock_irqsave(&cwq->lock, flags); | |
340 | cwq->current_work = NULL; | |
341 | } | |
342 | cwq->run_depth--; | |
343 | spin_unlock_irqrestore(&cwq->lock, flags); | |
344 | } | |
345 | ||
346 | static int worker_thread(void *__cwq) | |
347 | { | |
348 | struct cpu_workqueue_struct *cwq = __cwq; | |
349 | DECLARE_WAITQUEUE(wait, current); | |
350 | struct k_sigaction sa; | |
351 | sigset_t blocked; | |
352 | ||
353 | if (!cwq->wq->freezeable) | |
354 | current->flags |= PF_NOFREEZE; | |
355 | ||
356 | set_user_nice(current, -5); | |
357 | ||
358 | /* Block and flush all signals */ | |
359 | sigfillset(&blocked); | |
360 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
361 | flush_signals(current); | |
362 | ||
363 | /* | |
364 | * We inherited MPOL_INTERLEAVE from the booting kernel. | |
365 | * Set MPOL_DEFAULT to insure node local allocations. | |
366 | */ | |
367 | numa_default_policy(); | |
368 | ||
369 | /* SIG_IGN makes children autoreap: see do_notify_parent(). */ | |
370 | sa.sa.sa_handler = SIG_IGN; | |
371 | sa.sa.sa_flags = 0; | |
372 | siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); | |
373 | do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); | |
374 | ||
375 | set_current_state(TASK_INTERRUPTIBLE); | |
376 | while (!kthread_should_stop()) { | |
377 | if (cwq->wq->freezeable) | |
378 | try_to_freeze(); | |
379 | ||
380 | add_wait_queue(&cwq->more_work, &wait); | |
381 | if (list_empty(&cwq->worklist)) | |
382 | schedule(); | |
383 | else | |
384 | __set_current_state(TASK_RUNNING); | |
385 | remove_wait_queue(&cwq->more_work, &wait); | |
386 | ||
387 | if (!list_empty(&cwq->worklist)) | |
388 | run_workqueue(cwq); | |
389 | set_current_state(TASK_INTERRUPTIBLE); | |
390 | } | |
391 | __set_current_state(TASK_RUNNING); | |
392 | return 0; | |
393 | } | |
394 | ||
395 | struct wq_barrier { | |
396 | struct work_struct work; | |
397 | struct completion done; | |
398 | }; | |
399 | ||
400 | static void wq_barrier_func(struct work_struct *work) | |
401 | { | |
402 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
403 | complete(&barr->done); | |
404 | } | |
405 | ||
406 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, | |
407 | struct wq_barrier *barr, int tail) | |
408 | { | |
409 | INIT_WORK(&barr->work, wq_barrier_func); | |
410 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); | |
411 | ||
412 | init_completion(&barr->done); | |
413 | ||
414 | insert_work(cwq, &barr->work, tail); | |
415 | } | |
416 | ||
417 | static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) | |
418 | { | |
419 | if (cwq->thread == current) { | |
420 | /* | |
421 | * Probably keventd trying to flush its own queue. So simply run | |
422 | * it by hand rather than deadlocking. | |
423 | */ | |
424 | preempt_enable(); | |
425 | /* | |
426 | * We can still touch *cwq here because we are keventd, and | |
427 | * hot-unplug will be waiting us to exit. | |
428 | */ | |
429 | run_workqueue(cwq); | |
430 | preempt_disable(); | |
431 | } else { | |
432 | struct wq_barrier barr; | |
433 | int active = 0; | |
434 | ||
435 | spin_lock_irq(&cwq->lock); | |
436 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
437 | insert_wq_barrier(cwq, &barr, 1); | |
438 | active = 1; | |
439 | } | |
440 | spin_unlock_irq(&cwq->lock); | |
441 | ||
442 | if (active) { | |
443 | preempt_enable(); | |
444 | wait_for_completion(&barr.done); | |
445 | preempt_disable(); | |
446 | } | |
447 | } | |
448 | } | |
449 | ||
450 | /** | |
451 | * flush_workqueue - ensure that any scheduled work has run to completion. | |
452 | * @wq: workqueue to flush | |
453 | * | |
454 | * Forces execution of the workqueue and blocks until its completion. | |
455 | * This is typically used in driver shutdown handlers. | |
456 | * | |
457 | * We sleep until all works which were queued on entry have been handled, | |
458 | * but we are not livelocked by new incoming ones. | |
459 | * | |
460 | * This function used to run the workqueues itself. Now we just wait for the | |
461 | * helper threads to do it. | |
462 | */ | |
463 | void fastcall flush_workqueue(struct workqueue_struct *wq) | |
464 | { | |
465 | preempt_disable(); /* CPU hotplug */ | |
466 | if (is_single_threaded(wq)) { | |
467 | /* Always use first cpu's area. */ | |
468 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu)); | |
469 | } else { | |
470 | int cpu; | |
471 | ||
472 | for_each_online_cpu(cpu) | |
473 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); | |
474 | } | |
475 | preempt_enable(); | |
476 | } | |
477 | EXPORT_SYMBOL_GPL(flush_workqueue); | |
478 | ||
479 | static void wait_on_work(struct cpu_workqueue_struct *cwq, | |
480 | struct work_struct *work) | |
481 | { | |
482 | struct wq_barrier barr; | |
483 | int running = 0; | |
484 | ||
485 | spin_lock_irq(&cwq->lock); | |
486 | if (unlikely(cwq->current_work == work)) { | |
487 | insert_wq_barrier(cwq, &barr, 0); | |
488 | running = 1; | |
489 | } | |
490 | spin_unlock_irq(&cwq->lock); | |
491 | ||
492 | if (unlikely(running)) { | |
493 | mutex_unlock(&workqueue_mutex); | |
494 | wait_for_completion(&barr.done); | |
495 | mutex_lock(&workqueue_mutex); | |
496 | } | |
497 | } | |
498 | ||
499 | /** | |
500 | * flush_work - block until a work_struct's callback has terminated | |
501 | * @wq: the workqueue on which the work is queued | |
502 | * @work: the work which is to be flushed | |
503 | * | |
504 | * flush_work() will attempt to cancel the work if it is queued. If the work's | |
505 | * callback appears to be running, flush_work() will block until it has | |
506 | * completed. | |
507 | * | |
508 | * flush_work() is designed to be used when the caller is tearing down data | |
509 | * structures which the callback function operates upon. It is expected that, | |
510 | * prior to calling flush_work(), the caller has arranged for the work to not | |
511 | * be requeued. | |
512 | */ | |
513 | void flush_work(struct workqueue_struct *wq, struct work_struct *work) | |
514 | { | |
515 | struct cpu_workqueue_struct *cwq; | |
516 | ||
517 | mutex_lock(&workqueue_mutex); | |
518 | cwq = get_wq_data(work); | |
519 | /* Was it ever queued ? */ | |
520 | if (!cwq) | |
521 | goto out; | |
522 | ||
523 | /* | |
524 | * This work can't be re-queued, and the lock above protects us | |
525 | * from take_over_work(), no need to re-check that get_wq_data() | |
526 | * is still the same when we take cwq->lock. | |
527 | */ | |
528 | spin_lock_irq(&cwq->lock); | |
529 | list_del_init(&work->entry); | |
530 | work_release(work); | |
531 | spin_unlock_irq(&cwq->lock); | |
532 | ||
533 | if (is_single_threaded(wq)) { | |
534 | /* Always use first cpu's area. */ | |
535 | wait_on_work(per_cpu_ptr(wq->cpu_wq, singlethread_cpu), work); | |
536 | } else { | |
537 | int cpu; | |
538 | ||
539 | for_each_online_cpu(cpu) | |
540 | wait_on_work(per_cpu_ptr(wq->cpu_wq, cpu), work); | |
541 | } | |
542 | out: | |
543 | mutex_unlock(&workqueue_mutex); | |
544 | } | |
545 | EXPORT_SYMBOL_GPL(flush_work); | |
546 | ||
547 | static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, | |
548 | int cpu) | |
549 | { | |
550 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
551 | struct task_struct *p; | |
552 | ||
553 | spin_lock_init(&cwq->lock); | |
554 | cwq->wq = wq; | |
555 | cwq->thread = NULL; | |
556 | INIT_LIST_HEAD(&cwq->worklist); | |
557 | init_waitqueue_head(&cwq->more_work); | |
558 | ||
559 | if (is_single_threaded(wq)) | |
560 | p = kthread_create(worker_thread, cwq, "%s", wq->name); | |
561 | else | |
562 | p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); | |
563 | if (IS_ERR(p)) | |
564 | return NULL; | |
565 | cwq->thread = p; | |
566 | return p; | |
567 | } | |
568 | ||
569 | struct workqueue_struct *__create_workqueue(const char *name, | |
570 | int singlethread, int freezeable) | |
571 | { | |
572 | int cpu, destroy = 0; | |
573 | struct workqueue_struct *wq; | |
574 | struct task_struct *p; | |
575 | ||
576 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); | |
577 | if (!wq) | |
578 | return NULL; | |
579 | ||
580 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); | |
581 | if (!wq->cpu_wq) { | |
582 | kfree(wq); | |
583 | return NULL; | |
584 | } | |
585 | ||
586 | wq->name = name; | |
587 | wq->freezeable = freezeable; | |
588 | ||
589 | mutex_lock(&workqueue_mutex); | |
590 | if (singlethread) { | |
591 | INIT_LIST_HEAD(&wq->list); | |
592 | p = create_workqueue_thread(wq, singlethread_cpu); | |
593 | if (!p) | |
594 | destroy = 1; | |
595 | else | |
596 | wake_up_process(p); | |
597 | } else { | |
598 | list_add(&wq->list, &workqueues); | |
599 | for_each_online_cpu(cpu) { | |
600 | p = create_workqueue_thread(wq, cpu); | |
601 | if (p) { | |
602 | kthread_bind(p, cpu); | |
603 | wake_up_process(p); | |
604 | } else | |
605 | destroy = 1; | |
606 | } | |
607 | } | |
608 | mutex_unlock(&workqueue_mutex); | |
609 | ||
610 | /* | |
611 | * Was there any error during startup? If yes then clean up: | |
612 | */ | |
613 | if (destroy) { | |
614 | destroy_workqueue(wq); | |
615 | wq = NULL; | |
616 | } | |
617 | return wq; | |
618 | } | |
619 | EXPORT_SYMBOL_GPL(__create_workqueue); | |
620 | ||
621 | static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) | |
622 | { | |
623 | struct cpu_workqueue_struct *cwq; | |
624 | unsigned long flags; | |
625 | struct task_struct *p; | |
626 | ||
627 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
628 | spin_lock_irqsave(&cwq->lock, flags); | |
629 | p = cwq->thread; | |
630 | cwq->thread = NULL; | |
631 | spin_unlock_irqrestore(&cwq->lock, flags); | |
632 | if (p) | |
633 | kthread_stop(p); | |
634 | } | |
635 | ||
636 | /** | |
637 | * destroy_workqueue - safely terminate a workqueue | |
638 | * @wq: target workqueue | |
639 | * | |
640 | * Safely destroy a workqueue. All work currently pending will be done first. | |
641 | */ | |
642 | void destroy_workqueue(struct workqueue_struct *wq) | |
643 | { | |
644 | int cpu; | |
645 | ||
646 | flush_workqueue(wq); | |
647 | ||
648 | /* We don't need the distraction of CPUs appearing and vanishing. */ | |
649 | mutex_lock(&workqueue_mutex); | |
650 | if (is_single_threaded(wq)) | |
651 | cleanup_workqueue_thread(wq, singlethread_cpu); | |
652 | else { | |
653 | for_each_online_cpu(cpu) | |
654 | cleanup_workqueue_thread(wq, cpu); | |
655 | list_del(&wq->list); | |
656 | } | |
657 | mutex_unlock(&workqueue_mutex); | |
658 | free_percpu(wq->cpu_wq); | |
659 | kfree(wq); | |
660 | } | |
661 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
662 | ||
663 | static struct workqueue_struct *keventd_wq; | |
664 | ||
665 | /** | |
666 | * schedule_work - put work task in global workqueue | |
667 | * @work: job to be done | |
668 | * | |
669 | * This puts a job in the kernel-global workqueue. | |
670 | */ | |
671 | int fastcall schedule_work(struct work_struct *work) | |
672 | { | |
673 | return queue_work(keventd_wq, work); | |
674 | } | |
675 | EXPORT_SYMBOL(schedule_work); | |
676 | ||
677 | /** | |
678 | * schedule_delayed_work - put work task in global workqueue after delay | |
679 | * @dwork: job to be done | |
680 | * @delay: number of jiffies to wait or 0 for immediate execution | |
681 | * | |
682 | * After waiting for a given time this puts a job in the kernel-global | |
683 | * workqueue. | |
684 | */ | |
685 | int fastcall schedule_delayed_work(struct delayed_work *dwork, | |
686 | unsigned long delay) | |
687 | { | |
688 | timer_stats_timer_set_start_info(&dwork->timer); | |
689 | return queue_delayed_work(keventd_wq, dwork, delay); | |
690 | } | |
691 | EXPORT_SYMBOL(schedule_delayed_work); | |
692 | ||
693 | /** | |
694 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
695 | * @cpu: cpu to use | |
696 | * @dwork: job to be done | |
697 | * @delay: number of jiffies to wait | |
698 | * | |
699 | * After waiting for a given time this puts a job in the kernel-global | |
700 | * workqueue on the specified CPU. | |
701 | */ | |
702 | int schedule_delayed_work_on(int cpu, | |
703 | struct delayed_work *dwork, unsigned long delay) | |
704 | { | |
705 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); | |
706 | } | |
707 | EXPORT_SYMBOL(schedule_delayed_work_on); | |
708 | ||
709 | /** | |
710 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
711 | * @func: the function to call | |
712 | * | |
713 | * Returns zero on success. | |
714 | * Returns -ve errno on failure. | |
715 | * | |
716 | * Appears to be racy against CPU hotplug. | |
717 | * | |
718 | * schedule_on_each_cpu() is very slow. | |
719 | */ | |
720 | int schedule_on_each_cpu(work_func_t func) | |
721 | { | |
722 | int cpu; | |
723 | struct work_struct *works; | |
724 | ||
725 | works = alloc_percpu(struct work_struct); | |
726 | if (!works) | |
727 | return -ENOMEM; | |
728 | ||
729 | preempt_disable(); /* CPU hotplug */ | |
730 | for_each_online_cpu(cpu) { | |
731 | struct work_struct *work = per_cpu_ptr(works, cpu); | |
732 | ||
733 | INIT_WORK(work, func); | |
734 | set_bit(WORK_STRUCT_PENDING, work_data_bits(work)); | |
735 | __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work); | |
736 | } | |
737 | preempt_enable(); | |
738 | flush_workqueue(keventd_wq); | |
739 | free_percpu(works); | |
740 | return 0; | |
741 | } | |
742 | ||
743 | void flush_scheduled_work(void) | |
744 | { | |
745 | flush_workqueue(keventd_wq); | |
746 | } | |
747 | EXPORT_SYMBOL(flush_scheduled_work); | |
748 | ||
749 | void flush_work_keventd(struct work_struct *work) | |
750 | { | |
751 | flush_work(keventd_wq, work); | |
752 | } | |
753 | EXPORT_SYMBOL(flush_work_keventd); | |
754 | ||
755 | /** | |
756 | * cancel_rearming_delayed_workqueue - reliably kill off a delayed work whose handler rearms the delayed work. | |
757 | * @wq: the controlling workqueue structure | |
758 | * @dwork: the delayed work struct | |
759 | */ | |
760 | void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, | |
761 | struct delayed_work *dwork) | |
762 | { | |
763 | while (!cancel_delayed_work(dwork)) | |
764 | flush_workqueue(wq); | |
765 | } | |
766 | EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); | |
767 | ||
768 | /** | |
769 | * cancel_rearming_delayed_work - reliably kill off a delayed keventd work whose handler rearms the delayed work. | |
770 | * @dwork: the delayed work struct | |
771 | */ | |
772 | void cancel_rearming_delayed_work(struct delayed_work *dwork) | |
773 | { | |
774 | cancel_rearming_delayed_workqueue(keventd_wq, dwork); | |
775 | } | |
776 | EXPORT_SYMBOL(cancel_rearming_delayed_work); | |
777 | ||
778 | /** | |
779 | * execute_in_process_context - reliably execute the routine with user context | |
780 | * @fn: the function to execute | |
781 | * @ew: guaranteed storage for the execute work structure (must | |
782 | * be available when the work executes) | |
783 | * | |
784 | * Executes the function immediately if process context is available, | |
785 | * otherwise schedules the function for delayed execution. | |
786 | * | |
787 | * Returns: 0 - function was executed | |
788 | * 1 - function was scheduled for execution | |
789 | */ | |
790 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) | |
791 | { | |
792 | if (!in_interrupt()) { | |
793 | fn(&ew->work); | |
794 | return 0; | |
795 | } | |
796 | ||
797 | INIT_WORK(&ew->work, fn); | |
798 | schedule_work(&ew->work); | |
799 | ||
800 | return 1; | |
801 | } | |
802 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
803 | ||
804 | int keventd_up(void) | |
805 | { | |
806 | return keventd_wq != NULL; | |
807 | } | |
808 | ||
809 | int current_is_keventd(void) | |
810 | { | |
811 | struct cpu_workqueue_struct *cwq; | |
812 | int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ | |
813 | int ret = 0; | |
814 | ||
815 | BUG_ON(!keventd_wq); | |
816 | ||
817 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); | |
818 | if (current == cwq->thread) | |
819 | ret = 1; | |
820 | ||
821 | return ret; | |
822 | ||
823 | } | |
824 | ||
825 | /* Take the work from this (downed) CPU. */ | |
826 | static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) | |
827 | { | |
828 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
829 | struct list_head list; | |
830 | struct work_struct *work; | |
831 | ||
832 | spin_lock_irq(&cwq->lock); | |
833 | list_replace_init(&cwq->worklist, &list); | |
834 | ||
835 | while (!list_empty(&list)) { | |
836 | printk("Taking work for %s\n", wq->name); | |
837 | work = list_entry(list.next,struct work_struct,entry); | |
838 | list_del(&work->entry); | |
839 | __queue_work(per_cpu_ptr(wq->cpu_wq, smp_processor_id()), work); | |
840 | } | |
841 | spin_unlock_irq(&cwq->lock); | |
842 | } | |
843 | ||
844 | /* We're holding the cpucontrol mutex here */ | |
845 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
846 | unsigned long action, | |
847 | void *hcpu) | |
848 | { | |
849 | unsigned int hotcpu = (unsigned long)hcpu; | |
850 | struct workqueue_struct *wq; | |
851 | ||
852 | switch (action) { | |
853 | case CPU_UP_PREPARE: | |
854 | mutex_lock(&workqueue_mutex); | |
855 | /* Create a new workqueue thread for it. */ | |
856 | list_for_each_entry(wq, &workqueues, list) { | |
857 | if (!create_workqueue_thread(wq, hotcpu)) { | |
858 | printk("workqueue for %i failed\n", hotcpu); | |
859 | return NOTIFY_BAD; | |
860 | } | |
861 | } | |
862 | break; | |
863 | ||
864 | case CPU_ONLINE: | |
865 | /* Kick off worker threads. */ | |
866 | list_for_each_entry(wq, &workqueues, list) { | |
867 | struct cpu_workqueue_struct *cwq; | |
868 | ||
869 | cwq = per_cpu_ptr(wq->cpu_wq, hotcpu); | |
870 | kthread_bind(cwq->thread, hotcpu); | |
871 | wake_up_process(cwq->thread); | |
872 | } | |
873 | mutex_unlock(&workqueue_mutex); | |
874 | break; | |
875 | ||
876 | case CPU_UP_CANCELED: | |
877 | list_for_each_entry(wq, &workqueues, list) { | |
878 | if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread) | |
879 | continue; | |
880 | /* Unbind so it can run. */ | |
881 | kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread, | |
882 | any_online_cpu(cpu_online_map)); | |
883 | cleanup_workqueue_thread(wq, hotcpu); | |
884 | } | |
885 | mutex_unlock(&workqueue_mutex); | |
886 | break; | |
887 | ||
888 | case CPU_DOWN_PREPARE: | |
889 | mutex_lock(&workqueue_mutex); | |
890 | break; | |
891 | ||
892 | case CPU_DOWN_FAILED: | |
893 | mutex_unlock(&workqueue_mutex); | |
894 | break; | |
895 | ||
896 | case CPU_DEAD: | |
897 | list_for_each_entry(wq, &workqueues, list) | |
898 | cleanup_workqueue_thread(wq, hotcpu); | |
899 | list_for_each_entry(wq, &workqueues, list) | |
900 | take_over_work(wq, hotcpu); | |
901 | mutex_unlock(&workqueue_mutex); | |
902 | break; | |
903 | } | |
904 | ||
905 | return NOTIFY_OK; | |
906 | } | |
907 | ||
908 | void init_workqueues(void) | |
909 | { | |
910 | singlethread_cpu = first_cpu(cpu_possible_map); | |
911 | hotcpu_notifier(workqueue_cpu_callback, 0); | |
912 | keventd_wq = create_workqueue("events"); | |
913 | BUG_ON(!keventd_wq); | |
914 | } | |
915 |