Commit | Line | Data |
---|---|---|
1da177e4 LT |
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> | |
89ada679 CL |
15 | * |
16 | * Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>. | |
1da177e4 LT |
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> | |
1fa44eca | 30 | #include <linux/hardirq.h> |
1da177e4 LT |
31 | |
32 | /* | |
f756d5e2 NL |
33 | * The per-CPU workqueue (if single thread, we always use the first |
34 | * possible cpu). | |
1da177e4 LT |
35 | * |
36 | * The sequence counters are for flush_scheduled_work(). It wants to wait | |
37 | * until until all currently-scheduled works are completed, but it doesn't | |
38 | * want to be livelocked by new, incoming ones. So it waits until | |
39 | * remove_sequence is >= the insert_sequence which pertained when | |
40 | * flush_scheduled_work() was called. | |
41 | */ | |
42 | struct cpu_workqueue_struct { | |
43 | ||
44 | spinlock_t lock; | |
45 | ||
46 | long remove_sequence; /* Least-recently added (next to run) */ | |
47 | long insert_sequence; /* Next to add */ | |
48 | ||
49 | struct list_head worklist; | |
50 | wait_queue_head_t more_work; | |
51 | wait_queue_head_t work_done; | |
52 | ||
53 | struct workqueue_struct *wq; | |
36c8b586 | 54 | struct task_struct *thread; |
1da177e4 LT |
55 | |
56 | int run_depth; /* Detect run_workqueue() recursion depth */ | |
57 | } ____cacheline_aligned; | |
58 | ||
59 | /* | |
60 | * The externally visible workqueue abstraction is an array of | |
61 | * per-CPU workqueues: | |
62 | */ | |
63 | struct workqueue_struct { | |
89ada679 | 64 | struct cpu_workqueue_struct *cpu_wq; |
1da177e4 LT |
65 | const char *name; |
66 | struct list_head list; /* Empty if single thread */ | |
67 | }; | |
68 | ||
69 | /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove | |
70 | threads to each one as cpus come/go. */ | |
71 | static DEFINE_SPINLOCK(workqueue_lock); | |
72 | static LIST_HEAD(workqueues); | |
73 | ||
f756d5e2 NL |
74 | static int singlethread_cpu; |
75 | ||
1da177e4 LT |
76 | /* If it's single threaded, it isn't in the list of workqueues. */ |
77 | static inline int is_single_threaded(struct workqueue_struct *wq) | |
78 | { | |
79 | return list_empty(&wq->list); | |
80 | } | |
81 | ||
82 | /* Preempt must be disabled. */ | |
83 | static void __queue_work(struct cpu_workqueue_struct *cwq, | |
84 | struct work_struct *work) | |
85 | { | |
86 | unsigned long flags; | |
87 | ||
88 | spin_lock_irqsave(&cwq->lock, flags); | |
89 | work->wq_data = cwq; | |
90 | list_add_tail(&work->entry, &cwq->worklist); | |
91 | cwq->insert_sequence++; | |
92 | wake_up(&cwq->more_work); | |
93 | spin_unlock_irqrestore(&cwq->lock, flags); | |
94 | } | |
95 | ||
0fcb78c2 REB |
96 | /** |
97 | * queue_work - queue work on a workqueue | |
98 | * @wq: workqueue to use | |
99 | * @work: work to queue | |
100 | * | |
101 | * Returns non-zero if it was successfully added. | |
1da177e4 LT |
102 | * |
103 | * We queue the work to the CPU it was submitted, but there is no | |
104 | * guarantee that it will be processed by that CPU. | |
105 | */ | |
106 | int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) | |
107 | { | |
108 | int ret = 0, cpu = get_cpu(); | |
109 | ||
110 | if (!test_and_set_bit(0, &work->pending)) { | |
111 | if (unlikely(is_single_threaded(wq))) | |
f756d5e2 | 112 | cpu = singlethread_cpu; |
1da177e4 | 113 | BUG_ON(!list_empty(&work->entry)); |
89ada679 | 114 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
1da177e4 LT |
115 | ret = 1; |
116 | } | |
117 | put_cpu(); | |
118 | return ret; | |
119 | } | |
ae90dd5d | 120 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 LT |
121 | |
122 | static void delayed_work_timer_fn(unsigned long __data) | |
123 | { | |
124 | struct work_struct *work = (struct work_struct *)__data; | |
125 | struct workqueue_struct *wq = work->wq_data; | |
126 | int cpu = smp_processor_id(); | |
127 | ||
128 | if (unlikely(is_single_threaded(wq))) | |
f756d5e2 | 129 | cpu = singlethread_cpu; |
1da177e4 | 130 | |
89ada679 | 131 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
1da177e4 LT |
132 | } |
133 | ||
0fcb78c2 REB |
134 | /** |
135 | * queue_delayed_work - queue work on a workqueue after delay | |
136 | * @wq: workqueue to use | |
137 | * @work: work to queue | |
138 | * @delay: number of jiffies to wait before queueing | |
139 | * | |
140 | * Returns non-zero if it was successfully added. | |
141 | */ | |
1da177e4 LT |
142 | int fastcall queue_delayed_work(struct workqueue_struct *wq, |
143 | struct work_struct *work, unsigned long delay) | |
144 | { | |
145 | int ret = 0; | |
146 | struct timer_list *timer = &work->timer; | |
147 | ||
148 | if (!test_and_set_bit(0, &work->pending)) { | |
149 | BUG_ON(timer_pending(timer)); | |
150 | BUG_ON(!list_empty(&work->entry)); | |
151 | ||
152 | /* This stores wq for the moment, for the timer_fn */ | |
153 | work->wq_data = wq; | |
154 | timer->expires = jiffies + delay; | |
155 | timer->data = (unsigned long)work; | |
156 | timer->function = delayed_work_timer_fn; | |
157 | add_timer(timer); | |
158 | ret = 1; | |
159 | } | |
160 | return ret; | |
161 | } | |
ae90dd5d | 162 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 163 | |
0fcb78c2 REB |
164 | /** |
165 | * queue_delayed_work_on - queue work on specific CPU after delay | |
166 | * @cpu: CPU number to execute work on | |
167 | * @wq: workqueue to use | |
168 | * @work: work to queue | |
169 | * @delay: number of jiffies to wait before queueing | |
170 | * | |
171 | * Returns non-zero if it was successfully added. | |
172 | */ | |
7a6bc1cd VP |
173 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
174 | struct work_struct *work, unsigned long delay) | |
175 | { | |
176 | int ret = 0; | |
177 | struct timer_list *timer = &work->timer; | |
178 | ||
179 | if (!test_and_set_bit(0, &work->pending)) { | |
180 | BUG_ON(timer_pending(timer)); | |
181 | BUG_ON(!list_empty(&work->entry)); | |
182 | ||
183 | /* This stores wq for the moment, for the timer_fn */ | |
184 | work->wq_data = wq; | |
185 | timer->expires = jiffies + delay; | |
186 | timer->data = (unsigned long)work; | |
187 | timer->function = delayed_work_timer_fn; | |
188 | add_timer_on(timer, cpu); | |
189 | ret = 1; | |
190 | } | |
191 | return ret; | |
192 | } | |
ae90dd5d | 193 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 194 | |
858119e1 | 195 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 LT |
196 | { |
197 | unsigned long flags; | |
198 | ||
199 | /* | |
200 | * Keep taking off work from the queue until | |
201 | * done. | |
202 | */ | |
203 | spin_lock_irqsave(&cwq->lock, flags); | |
204 | cwq->run_depth++; | |
205 | if (cwq->run_depth > 3) { | |
206 | /* morton gets to eat his hat */ | |
207 | printk("%s: recursion depth exceeded: %d\n", | |
208 | __FUNCTION__, cwq->run_depth); | |
209 | dump_stack(); | |
210 | } | |
211 | while (!list_empty(&cwq->worklist)) { | |
212 | struct work_struct *work = list_entry(cwq->worklist.next, | |
213 | struct work_struct, entry); | |
214 | void (*f) (void *) = work->func; | |
215 | void *data = work->data; | |
216 | ||
217 | list_del_init(cwq->worklist.next); | |
218 | spin_unlock_irqrestore(&cwq->lock, flags); | |
219 | ||
220 | BUG_ON(work->wq_data != cwq); | |
221 | clear_bit(0, &work->pending); | |
222 | f(data); | |
223 | ||
224 | spin_lock_irqsave(&cwq->lock, flags); | |
225 | cwq->remove_sequence++; | |
226 | wake_up(&cwq->work_done); | |
227 | } | |
228 | cwq->run_depth--; | |
229 | spin_unlock_irqrestore(&cwq->lock, flags); | |
230 | } | |
231 | ||
232 | static int worker_thread(void *__cwq) | |
233 | { | |
234 | struct cpu_workqueue_struct *cwq = __cwq; | |
235 | DECLARE_WAITQUEUE(wait, current); | |
236 | struct k_sigaction sa; | |
237 | sigset_t blocked; | |
238 | ||
239 | current->flags |= PF_NOFREEZE; | |
240 | ||
241 | set_user_nice(current, -5); | |
242 | ||
243 | /* Block and flush all signals */ | |
244 | sigfillset(&blocked); | |
245 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
246 | flush_signals(current); | |
247 | ||
248 | /* SIG_IGN makes children autoreap: see do_notify_parent(). */ | |
249 | sa.sa.sa_handler = SIG_IGN; | |
250 | sa.sa.sa_flags = 0; | |
251 | siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); | |
252 | do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); | |
253 | ||
254 | set_current_state(TASK_INTERRUPTIBLE); | |
255 | while (!kthread_should_stop()) { | |
256 | add_wait_queue(&cwq->more_work, &wait); | |
257 | if (list_empty(&cwq->worklist)) | |
258 | schedule(); | |
259 | else | |
260 | __set_current_state(TASK_RUNNING); | |
261 | remove_wait_queue(&cwq->more_work, &wait); | |
262 | ||
263 | if (!list_empty(&cwq->worklist)) | |
264 | run_workqueue(cwq); | |
265 | set_current_state(TASK_INTERRUPTIBLE); | |
266 | } | |
267 | __set_current_state(TASK_RUNNING); | |
268 | return 0; | |
269 | } | |
270 | ||
271 | static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) | |
272 | { | |
273 | if (cwq->thread == current) { | |
274 | /* | |
275 | * Probably keventd trying to flush its own queue. So simply run | |
276 | * it by hand rather than deadlocking. | |
277 | */ | |
278 | run_workqueue(cwq); | |
279 | } else { | |
280 | DEFINE_WAIT(wait); | |
281 | long sequence_needed; | |
282 | ||
283 | spin_lock_irq(&cwq->lock); | |
284 | sequence_needed = cwq->insert_sequence; | |
285 | ||
286 | while (sequence_needed - cwq->remove_sequence > 0) { | |
287 | prepare_to_wait(&cwq->work_done, &wait, | |
288 | TASK_UNINTERRUPTIBLE); | |
289 | spin_unlock_irq(&cwq->lock); | |
290 | schedule(); | |
291 | spin_lock_irq(&cwq->lock); | |
292 | } | |
293 | finish_wait(&cwq->work_done, &wait); | |
294 | spin_unlock_irq(&cwq->lock); | |
295 | } | |
296 | } | |
297 | ||
0fcb78c2 | 298 | /** |
1da177e4 | 299 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 300 | * @wq: workqueue to flush |
1da177e4 LT |
301 | * |
302 | * Forces execution of the workqueue and blocks until its completion. | |
303 | * This is typically used in driver shutdown handlers. | |
304 | * | |
305 | * This function will sample each workqueue's current insert_sequence number and | |
306 | * will sleep until the head sequence is greater than or equal to that. This | |
307 | * means that we sleep until all works which were queued on entry have been | |
308 | * handled, but we are not livelocked by new incoming ones. | |
309 | * | |
310 | * This function used to run the workqueues itself. Now we just wait for the | |
311 | * helper threads to do it. | |
312 | */ | |
313 | void fastcall flush_workqueue(struct workqueue_struct *wq) | |
314 | { | |
315 | might_sleep(); | |
316 | ||
317 | if (is_single_threaded(wq)) { | |
bce61dd4 | 318 | /* Always use first cpu's area. */ |
f756d5e2 | 319 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu)); |
1da177e4 LT |
320 | } else { |
321 | int cpu; | |
322 | ||
323 | lock_cpu_hotplug(); | |
324 | for_each_online_cpu(cpu) | |
89ada679 | 325 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
1da177e4 LT |
326 | unlock_cpu_hotplug(); |
327 | } | |
328 | } | |
ae90dd5d | 329 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 LT |
330 | |
331 | static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, | |
332 | int cpu) | |
333 | { | |
89ada679 | 334 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 LT |
335 | struct task_struct *p; |
336 | ||
337 | spin_lock_init(&cwq->lock); | |
338 | cwq->wq = wq; | |
339 | cwq->thread = NULL; | |
340 | cwq->insert_sequence = 0; | |
341 | cwq->remove_sequence = 0; | |
342 | INIT_LIST_HEAD(&cwq->worklist); | |
343 | init_waitqueue_head(&cwq->more_work); | |
344 | init_waitqueue_head(&cwq->work_done); | |
345 | ||
346 | if (is_single_threaded(wq)) | |
347 | p = kthread_create(worker_thread, cwq, "%s", wq->name); | |
348 | else | |
349 | p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); | |
350 | if (IS_ERR(p)) | |
351 | return NULL; | |
352 | cwq->thread = p; | |
353 | return p; | |
354 | } | |
355 | ||
356 | struct workqueue_struct *__create_workqueue(const char *name, | |
357 | int singlethread) | |
358 | { | |
359 | int cpu, destroy = 0; | |
360 | struct workqueue_struct *wq; | |
361 | struct task_struct *p; | |
362 | ||
dd392710 | 363 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
1da177e4 LT |
364 | if (!wq) |
365 | return NULL; | |
1da177e4 | 366 | |
89ada679 | 367 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); |
676121fc BC |
368 | if (!wq->cpu_wq) { |
369 | kfree(wq); | |
370 | return NULL; | |
371 | } | |
372 | ||
1da177e4 LT |
373 | wq->name = name; |
374 | /* We don't need the distraction of CPUs appearing and vanishing. */ | |
375 | lock_cpu_hotplug(); | |
376 | if (singlethread) { | |
377 | INIT_LIST_HEAD(&wq->list); | |
f756d5e2 | 378 | p = create_workqueue_thread(wq, singlethread_cpu); |
1da177e4 LT |
379 | if (!p) |
380 | destroy = 1; | |
381 | else | |
382 | wake_up_process(p); | |
383 | } else { | |
384 | spin_lock(&workqueue_lock); | |
385 | list_add(&wq->list, &workqueues); | |
386 | spin_unlock(&workqueue_lock); | |
387 | for_each_online_cpu(cpu) { | |
388 | p = create_workqueue_thread(wq, cpu); | |
389 | if (p) { | |
390 | kthread_bind(p, cpu); | |
391 | wake_up_process(p); | |
392 | } else | |
393 | destroy = 1; | |
394 | } | |
395 | } | |
396 | unlock_cpu_hotplug(); | |
397 | ||
398 | /* | |
399 | * Was there any error during startup? If yes then clean up: | |
400 | */ | |
401 | if (destroy) { | |
402 | destroy_workqueue(wq); | |
403 | wq = NULL; | |
404 | } | |
405 | return wq; | |
406 | } | |
ae90dd5d | 407 | EXPORT_SYMBOL_GPL(__create_workqueue); |
1da177e4 LT |
408 | |
409 | static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) | |
410 | { | |
411 | struct cpu_workqueue_struct *cwq; | |
412 | unsigned long flags; | |
413 | struct task_struct *p; | |
414 | ||
89ada679 | 415 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 LT |
416 | spin_lock_irqsave(&cwq->lock, flags); |
417 | p = cwq->thread; | |
418 | cwq->thread = NULL; | |
419 | spin_unlock_irqrestore(&cwq->lock, flags); | |
420 | if (p) | |
421 | kthread_stop(p); | |
422 | } | |
423 | ||
0fcb78c2 REB |
424 | /** |
425 | * destroy_workqueue - safely terminate a workqueue | |
426 | * @wq: target workqueue | |
427 | * | |
428 | * Safely destroy a workqueue. All work currently pending will be done first. | |
429 | */ | |
1da177e4 LT |
430 | void destroy_workqueue(struct workqueue_struct *wq) |
431 | { | |
432 | int cpu; | |
433 | ||
434 | flush_workqueue(wq); | |
435 | ||
436 | /* We don't need the distraction of CPUs appearing and vanishing. */ | |
437 | lock_cpu_hotplug(); | |
438 | if (is_single_threaded(wq)) | |
f756d5e2 | 439 | cleanup_workqueue_thread(wq, singlethread_cpu); |
1da177e4 LT |
440 | else { |
441 | for_each_online_cpu(cpu) | |
442 | cleanup_workqueue_thread(wq, cpu); | |
443 | spin_lock(&workqueue_lock); | |
444 | list_del(&wq->list); | |
445 | spin_unlock(&workqueue_lock); | |
446 | } | |
447 | unlock_cpu_hotplug(); | |
89ada679 | 448 | free_percpu(wq->cpu_wq); |
1da177e4 LT |
449 | kfree(wq); |
450 | } | |
ae90dd5d | 451 | EXPORT_SYMBOL_GPL(destroy_workqueue); |
1da177e4 LT |
452 | |
453 | static struct workqueue_struct *keventd_wq; | |
454 | ||
0fcb78c2 REB |
455 | /** |
456 | * schedule_work - put work task in global workqueue | |
457 | * @work: job to be done | |
458 | * | |
459 | * This puts a job in the kernel-global workqueue. | |
460 | */ | |
1da177e4 LT |
461 | int fastcall schedule_work(struct work_struct *work) |
462 | { | |
463 | return queue_work(keventd_wq, work); | |
464 | } | |
ae90dd5d | 465 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 466 | |
0fcb78c2 REB |
467 | /** |
468 | * schedule_delayed_work - put work task in global workqueue after delay | |
469 | * @work: job to be done | |
470 | * @delay: number of jiffies to wait | |
471 | * | |
472 | * After waiting for a given time this puts a job in the kernel-global | |
473 | * workqueue. | |
474 | */ | |
1da177e4 LT |
475 | int fastcall schedule_delayed_work(struct work_struct *work, unsigned long delay) |
476 | { | |
477 | return queue_delayed_work(keventd_wq, work, delay); | |
478 | } | |
ae90dd5d | 479 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 480 | |
0fcb78c2 REB |
481 | /** |
482 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
483 | * @cpu: cpu to use | |
484 | * @work: job to be done | |
485 | * @delay: number of jiffies to wait | |
486 | * | |
487 | * After waiting for a given time this puts a job in the kernel-global | |
488 | * workqueue on the specified CPU. | |
489 | */ | |
1da177e4 LT |
490 | int schedule_delayed_work_on(int cpu, |
491 | struct work_struct *work, unsigned long delay) | |
492 | { | |
7a6bc1cd | 493 | return queue_delayed_work_on(cpu, keventd_wq, work, delay); |
1da177e4 | 494 | } |
ae90dd5d | 495 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 496 | |
b6136773 AM |
497 | /** |
498 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
499 | * @func: the function to call | |
500 | * @info: a pointer to pass to func() | |
501 | * | |
502 | * Returns zero on success. | |
503 | * Returns -ve errno on failure. | |
504 | * | |
505 | * Appears to be racy against CPU hotplug. | |
506 | * | |
507 | * schedule_on_each_cpu() is very slow. | |
508 | */ | |
509 | int schedule_on_each_cpu(void (*func)(void *info), void *info) | |
15316ba8 CL |
510 | { |
511 | int cpu; | |
b6136773 | 512 | struct work_struct *works; |
15316ba8 | 513 | |
b6136773 AM |
514 | works = alloc_percpu(struct work_struct); |
515 | if (!works) | |
15316ba8 | 516 | return -ENOMEM; |
b6136773 | 517 | |
15316ba8 | 518 | for_each_online_cpu(cpu) { |
b6136773 | 519 | INIT_WORK(per_cpu_ptr(works, cpu), func, info); |
15316ba8 | 520 | __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), |
b6136773 | 521 | per_cpu_ptr(works, cpu)); |
15316ba8 CL |
522 | } |
523 | flush_workqueue(keventd_wq); | |
b6136773 | 524 | free_percpu(works); |
15316ba8 CL |
525 | return 0; |
526 | } | |
527 | ||
1da177e4 LT |
528 | void flush_scheduled_work(void) |
529 | { | |
530 | flush_workqueue(keventd_wq); | |
531 | } | |
ae90dd5d | 532 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 LT |
533 | |
534 | /** | |
535 | * cancel_rearming_delayed_workqueue - reliably kill off a delayed | |
536 | * work whose handler rearms the delayed work. | |
537 | * @wq: the controlling workqueue structure | |
538 | * @work: the delayed work struct | |
539 | */ | |
81ddef77 JB |
540 | void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, |
541 | struct work_struct *work) | |
1da177e4 LT |
542 | { |
543 | while (!cancel_delayed_work(work)) | |
544 | flush_workqueue(wq); | |
545 | } | |
81ddef77 | 546 | EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); |
1da177e4 LT |
547 | |
548 | /** | |
549 | * cancel_rearming_delayed_work - reliably kill off a delayed keventd | |
550 | * work whose handler rearms the delayed work. | |
551 | * @work: the delayed work struct | |
552 | */ | |
553 | void cancel_rearming_delayed_work(struct work_struct *work) | |
554 | { | |
555 | cancel_rearming_delayed_workqueue(keventd_wq, work); | |
556 | } | |
557 | EXPORT_SYMBOL(cancel_rearming_delayed_work); | |
558 | ||
1fa44eca JB |
559 | /** |
560 | * execute_in_process_context - reliably execute the routine with user context | |
561 | * @fn: the function to execute | |
562 | * @data: data to pass to the function | |
563 | * @ew: guaranteed storage for the execute work structure (must | |
564 | * be available when the work executes) | |
565 | * | |
566 | * Executes the function immediately if process context is available, | |
567 | * otherwise schedules the function for delayed execution. | |
568 | * | |
569 | * Returns: 0 - function was executed | |
570 | * 1 - function was scheduled for execution | |
571 | */ | |
572 | int execute_in_process_context(void (*fn)(void *data), void *data, | |
573 | struct execute_work *ew) | |
574 | { | |
575 | if (!in_interrupt()) { | |
576 | fn(data); | |
577 | return 0; | |
578 | } | |
579 | ||
580 | INIT_WORK(&ew->work, fn, data); | |
581 | schedule_work(&ew->work); | |
582 | ||
583 | return 1; | |
584 | } | |
585 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
586 | ||
1da177e4 LT |
587 | int keventd_up(void) |
588 | { | |
589 | return keventd_wq != NULL; | |
590 | } | |
591 | ||
592 | int current_is_keventd(void) | |
593 | { | |
594 | struct cpu_workqueue_struct *cwq; | |
595 | int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ | |
596 | int ret = 0; | |
597 | ||
598 | BUG_ON(!keventd_wq); | |
599 | ||
89ada679 | 600 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
601 | if (current == cwq->thread) |
602 | ret = 1; | |
603 | ||
604 | return ret; | |
605 | ||
606 | } | |
607 | ||
608 | #ifdef CONFIG_HOTPLUG_CPU | |
609 | /* Take the work from this (downed) CPU. */ | |
610 | static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) | |
611 | { | |
89ada679 | 612 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
626ab0e6 | 613 | struct list_head list; |
1da177e4 LT |
614 | struct work_struct *work; |
615 | ||
616 | spin_lock_irq(&cwq->lock); | |
626ab0e6 | 617 | list_replace_init(&cwq->worklist, &list); |
1da177e4 LT |
618 | |
619 | while (!list_empty(&list)) { | |
620 | printk("Taking work for %s\n", wq->name); | |
621 | work = list_entry(list.next,struct work_struct,entry); | |
622 | list_del(&work->entry); | |
89ada679 | 623 | __queue_work(per_cpu_ptr(wq->cpu_wq, smp_processor_id()), work); |
1da177e4 LT |
624 | } |
625 | spin_unlock_irq(&cwq->lock); | |
626 | } | |
627 | ||
628 | /* We're holding the cpucontrol mutex here */ | |
9c7b216d | 629 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, |
1da177e4 LT |
630 | unsigned long action, |
631 | void *hcpu) | |
632 | { | |
633 | unsigned int hotcpu = (unsigned long)hcpu; | |
634 | struct workqueue_struct *wq; | |
635 | ||
636 | switch (action) { | |
637 | case CPU_UP_PREPARE: | |
638 | /* Create a new workqueue thread for it. */ | |
639 | list_for_each_entry(wq, &workqueues, list) { | |
230649da | 640 | if (!create_workqueue_thread(wq, hotcpu)) { |
1da177e4 LT |
641 | printk("workqueue for %i failed\n", hotcpu); |
642 | return NOTIFY_BAD; | |
643 | } | |
644 | } | |
645 | break; | |
646 | ||
647 | case CPU_ONLINE: | |
648 | /* Kick off worker threads. */ | |
649 | list_for_each_entry(wq, &workqueues, list) { | |
89ada679 CL |
650 | struct cpu_workqueue_struct *cwq; |
651 | ||
652 | cwq = per_cpu_ptr(wq->cpu_wq, hotcpu); | |
653 | kthread_bind(cwq->thread, hotcpu); | |
654 | wake_up_process(cwq->thread); | |
1da177e4 LT |
655 | } |
656 | break; | |
657 | ||
658 | case CPU_UP_CANCELED: | |
659 | list_for_each_entry(wq, &workqueues, list) { | |
fc75cdfa HC |
660 | if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread) |
661 | continue; | |
1da177e4 | 662 | /* Unbind so it can run. */ |
89ada679 | 663 | kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread, |
a4c4af7c | 664 | any_online_cpu(cpu_online_map)); |
1da177e4 LT |
665 | cleanup_workqueue_thread(wq, hotcpu); |
666 | } | |
667 | break; | |
668 | ||
669 | case CPU_DEAD: | |
670 | list_for_each_entry(wq, &workqueues, list) | |
671 | cleanup_workqueue_thread(wq, hotcpu); | |
672 | list_for_each_entry(wq, &workqueues, list) | |
673 | take_over_work(wq, hotcpu); | |
674 | break; | |
675 | } | |
676 | ||
677 | return NOTIFY_OK; | |
678 | } | |
679 | #endif | |
680 | ||
681 | void init_workqueues(void) | |
682 | { | |
f756d5e2 | 683 | singlethread_cpu = first_cpu(cpu_possible_map); |
1da177e4 LT |
684 | hotcpu_notifier(workqueue_cpu_callback, 0); |
685 | keventd_wq = create_workqueue("events"); | |
686 | BUG_ON(!keventd_wq); | |
687 | } | |
688 |