Commit | Line | Data |
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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> |
46934023 | 31 | #include <linux/mempolicy.h> |
1da177e4 LT |
32 | |
33 | /* | |
f756d5e2 NL |
34 | * The per-CPU workqueue (if single thread, we always use the first |
35 | * possible cpu). | |
1da177e4 LT |
36 | * |
37 | * The sequence counters are for flush_scheduled_work(). It wants to wait | |
9f5d785e | 38 | * until all currently-scheduled works are completed, but it doesn't |
1da177e4 LT |
39 | * want to be livelocked by new, incoming ones. So it waits until |
40 | * remove_sequence is >= the insert_sequence which pertained when | |
41 | * flush_scheduled_work() was called. | |
42 | */ | |
43 | struct cpu_workqueue_struct { | |
44 | ||
45 | spinlock_t lock; | |
46 | ||
47 | long remove_sequence; /* Least-recently added (next to run) */ | |
48 | long insert_sequence; /* Next to add */ | |
49 | ||
50 | struct list_head worklist; | |
51 | wait_queue_head_t more_work; | |
52 | wait_queue_head_t work_done; | |
53 | ||
54 | struct workqueue_struct *wq; | |
36c8b586 | 55 | struct task_struct *thread; |
1da177e4 LT |
56 | |
57 | int run_depth; /* Detect run_workqueue() recursion depth */ | |
58 | } ____cacheline_aligned; | |
59 | ||
60 | /* | |
61 | * The externally visible workqueue abstraction is an array of | |
62 | * per-CPU workqueues: | |
63 | */ | |
64 | struct workqueue_struct { | |
89ada679 | 65 | struct cpu_workqueue_struct *cpu_wq; |
1da177e4 LT |
66 | const char *name; |
67 | struct list_head list; /* Empty if single thread */ | |
68 | }; | |
69 | ||
70 | /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove | |
71 | threads to each one as cpus come/go. */ | |
9b41ea72 | 72 | static DEFINE_MUTEX(workqueue_mutex); |
1da177e4 LT |
73 | static LIST_HEAD(workqueues); |
74 | ||
f756d5e2 NL |
75 | static int singlethread_cpu; |
76 | ||
1da177e4 LT |
77 | /* If it's single threaded, it isn't in the list of workqueues. */ |
78 | static inline int is_single_threaded(struct workqueue_struct *wq) | |
79 | { | |
80 | return list_empty(&wq->list); | |
81 | } | |
82 | ||
83 | /* Preempt must be disabled. */ | |
84 | static void __queue_work(struct cpu_workqueue_struct *cwq, | |
85 | struct work_struct *work) | |
86 | { | |
87 | unsigned long flags; | |
88 | ||
89 | spin_lock_irqsave(&cwq->lock, flags); | |
90 | work->wq_data = cwq; | |
91 | list_add_tail(&work->entry, &cwq->worklist); | |
92 | cwq->insert_sequence++; | |
93 | wake_up(&cwq->more_work); | |
94 | spin_unlock_irqrestore(&cwq->lock, flags); | |
95 | } | |
96 | ||
0fcb78c2 REB |
97 | /** |
98 | * queue_work - queue work on a workqueue | |
99 | * @wq: workqueue to use | |
100 | * @work: work to queue | |
101 | * | |
057647fc | 102 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 LT |
103 | * |
104 | * We queue the work to the CPU it was submitted, but there is no | |
105 | * guarantee that it will be processed by that CPU. | |
106 | */ | |
107 | int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) | |
108 | { | |
109 | int ret = 0, cpu = get_cpu(); | |
110 | ||
111 | if (!test_and_set_bit(0, &work->pending)) { | |
112 | if (unlikely(is_single_threaded(wq))) | |
f756d5e2 | 113 | cpu = singlethread_cpu; |
1da177e4 | 114 | BUG_ON(!list_empty(&work->entry)); |
89ada679 | 115 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
1da177e4 LT |
116 | ret = 1; |
117 | } | |
118 | put_cpu(); | |
119 | return ret; | |
120 | } | |
ae90dd5d | 121 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 LT |
122 | |
123 | static void delayed_work_timer_fn(unsigned long __data) | |
124 | { | |
125 | struct work_struct *work = (struct work_struct *)__data; | |
126 | struct workqueue_struct *wq = work->wq_data; | |
127 | int cpu = smp_processor_id(); | |
128 | ||
129 | if (unlikely(is_single_threaded(wq))) | |
f756d5e2 | 130 | cpu = singlethread_cpu; |
1da177e4 | 131 | |
89ada679 | 132 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
1da177e4 LT |
133 | } |
134 | ||
0fcb78c2 REB |
135 | /** |
136 | * queue_delayed_work - queue work on a workqueue after delay | |
137 | * @wq: workqueue to use | |
138 | * @work: work to queue | |
139 | * @delay: number of jiffies to wait before queueing | |
140 | * | |
057647fc | 141 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 142 | */ |
1da177e4 LT |
143 | int fastcall queue_delayed_work(struct workqueue_struct *wq, |
144 | struct work_struct *work, unsigned long delay) | |
145 | { | |
146 | int ret = 0; | |
147 | struct timer_list *timer = &work->timer; | |
148 | ||
149 | if (!test_and_set_bit(0, &work->pending)) { | |
150 | BUG_ON(timer_pending(timer)); | |
151 | BUG_ON(!list_empty(&work->entry)); | |
152 | ||
153 | /* This stores wq for the moment, for the timer_fn */ | |
154 | work->wq_data = wq; | |
155 | timer->expires = jiffies + delay; | |
156 | timer->data = (unsigned long)work; | |
157 | timer->function = delayed_work_timer_fn; | |
158 | add_timer(timer); | |
159 | ret = 1; | |
160 | } | |
161 | return ret; | |
162 | } | |
ae90dd5d | 163 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 164 | |
0fcb78c2 REB |
165 | /** |
166 | * queue_delayed_work_on - queue work on specific CPU after delay | |
167 | * @cpu: CPU number to execute work on | |
168 | * @wq: workqueue to use | |
169 | * @work: work to queue | |
170 | * @delay: number of jiffies to wait before queueing | |
171 | * | |
057647fc | 172 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 173 | */ |
7a6bc1cd VP |
174 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
175 | struct work_struct *work, unsigned long delay) | |
176 | { | |
177 | int ret = 0; | |
178 | struct timer_list *timer = &work->timer; | |
179 | ||
180 | if (!test_and_set_bit(0, &work->pending)) { | |
181 | BUG_ON(timer_pending(timer)); | |
182 | BUG_ON(!list_empty(&work->entry)); | |
183 | ||
184 | /* This stores wq for the moment, for the timer_fn */ | |
185 | work->wq_data = wq; | |
186 | timer->expires = jiffies + delay; | |
187 | timer->data = (unsigned long)work; | |
188 | timer->function = delayed_work_timer_fn; | |
189 | add_timer_on(timer, cpu); | |
190 | ret = 1; | |
191 | } | |
192 | return ret; | |
193 | } | |
ae90dd5d | 194 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 195 | |
858119e1 | 196 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 LT |
197 | { |
198 | unsigned long flags; | |
199 | ||
200 | /* | |
201 | * Keep taking off work from the queue until | |
202 | * done. | |
203 | */ | |
204 | spin_lock_irqsave(&cwq->lock, flags); | |
205 | cwq->run_depth++; | |
206 | if (cwq->run_depth > 3) { | |
207 | /* morton gets to eat his hat */ | |
208 | printk("%s: recursion depth exceeded: %d\n", | |
209 | __FUNCTION__, cwq->run_depth); | |
210 | dump_stack(); | |
211 | } | |
212 | while (!list_empty(&cwq->worklist)) { | |
213 | struct work_struct *work = list_entry(cwq->worklist.next, | |
214 | struct work_struct, entry); | |
215 | void (*f) (void *) = work->func; | |
216 | void *data = work->data; | |
217 | ||
218 | list_del_init(cwq->worklist.next); | |
219 | spin_unlock_irqrestore(&cwq->lock, flags); | |
220 | ||
221 | BUG_ON(work->wq_data != cwq); | |
222 | clear_bit(0, &work->pending); | |
223 | f(data); | |
224 | ||
225 | spin_lock_irqsave(&cwq->lock, flags); | |
226 | cwq->remove_sequence++; | |
227 | wake_up(&cwq->work_done); | |
228 | } | |
229 | cwq->run_depth--; | |
230 | spin_unlock_irqrestore(&cwq->lock, flags); | |
231 | } | |
232 | ||
233 | static int worker_thread(void *__cwq) | |
234 | { | |
235 | struct cpu_workqueue_struct *cwq = __cwq; | |
236 | DECLARE_WAITQUEUE(wait, current); | |
237 | struct k_sigaction sa; | |
238 | sigset_t blocked; | |
239 | ||
240 | current->flags |= PF_NOFREEZE; | |
241 | ||
242 | set_user_nice(current, -5); | |
243 | ||
244 | /* Block and flush all signals */ | |
245 | sigfillset(&blocked); | |
246 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
247 | flush_signals(current); | |
248 | ||
46934023 CL |
249 | /* |
250 | * We inherited MPOL_INTERLEAVE from the booting kernel. | |
251 | * Set MPOL_DEFAULT to insure node local allocations. | |
252 | */ | |
253 | numa_default_policy(); | |
254 | ||
1da177e4 LT |
255 | /* SIG_IGN makes children autoreap: see do_notify_parent(). */ |
256 | sa.sa.sa_handler = SIG_IGN; | |
257 | sa.sa.sa_flags = 0; | |
258 | siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); | |
259 | do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); | |
260 | ||
261 | set_current_state(TASK_INTERRUPTIBLE); | |
262 | while (!kthread_should_stop()) { | |
263 | add_wait_queue(&cwq->more_work, &wait); | |
264 | if (list_empty(&cwq->worklist)) | |
265 | schedule(); | |
266 | else | |
267 | __set_current_state(TASK_RUNNING); | |
268 | remove_wait_queue(&cwq->more_work, &wait); | |
269 | ||
270 | if (!list_empty(&cwq->worklist)) | |
271 | run_workqueue(cwq); | |
272 | set_current_state(TASK_INTERRUPTIBLE); | |
273 | } | |
274 | __set_current_state(TASK_RUNNING); | |
275 | return 0; | |
276 | } | |
277 | ||
278 | static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) | |
279 | { | |
280 | if (cwq->thread == current) { | |
281 | /* | |
282 | * Probably keventd trying to flush its own queue. So simply run | |
283 | * it by hand rather than deadlocking. | |
284 | */ | |
285 | run_workqueue(cwq); | |
286 | } else { | |
287 | DEFINE_WAIT(wait); | |
288 | long sequence_needed; | |
289 | ||
290 | spin_lock_irq(&cwq->lock); | |
291 | sequence_needed = cwq->insert_sequence; | |
292 | ||
293 | while (sequence_needed - cwq->remove_sequence > 0) { | |
294 | prepare_to_wait(&cwq->work_done, &wait, | |
295 | TASK_UNINTERRUPTIBLE); | |
296 | spin_unlock_irq(&cwq->lock); | |
297 | schedule(); | |
298 | spin_lock_irq(&cwq->lock); | |
299 | } | |
300 | finish_wait(&cwq->work_done, &wait); | |
301 | spin_unlock_irq(&cwq->lock); | |
302 | } | |
303 | } | |
304 | ||
0fcb78c2 | 305 | /** |
1da177e4 | 306 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 307 | * @wq: workqueue to flush |
1da177e4 LT |
308 | * |
309 | * Forces execution of the workqueue and blocks until its completion. | |
310 | * This is typically used in driver shutdown handlers. | |
311 | * | |
312 | * This function will sample each workqueue's current insert_sequence number and | |
313 | * will sleep until the head sequence is greater than or equal to that. This | |
314 | * means that we sleep until all works which were queued on entry have been | |
315 | * handled, but we are not livelocked by new incoming ones. | |
316 | * | |
317 | * This function used to run the workqueues itself. Now we just wait for the | |
318 | * helper threads to do it. | |
319 | */ | |
320 | void fastcall flush_workqueue(struct workqueue_struct *wq) | |
321 | { | |
322 | might_sleep(); | |
323 | ||
324 | if (is_single_threaded(wq)) { | |
bce61dd4 | 325 | /* Always use first cpu's area. */ |
f756d5e2 | 326 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu)); |
1da177e4 LT |
327 | } else { |
328 | int cpu; | |
329 | ||
9b41ea72 | 330 | mutex_lock(&workqueue_mutex); |
1da177e4 | 331 | for_each_online_cpu(cpu) |
89ada679 | 332 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
9b41ea72 | 333 | mutex_unlock(&workqueue_mutex); |
1da177e4 LT |
334 | } |
335 | } | |
ae90dd5d | 336 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 LT |
337 | |
338 | static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, | |
339 | int cpu) | |
340 | { | |
89ada679 | 341 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 LT |
342 | struct task_struct *p; |
343 | ||
344 | spin_lock_init(&cwq->lock); | |
345 | cwq->wq = wq; | |
346 | cwq->thread = NULL; | |
347 | cwq->insert_sequence = 0; | |
348 | cwq->remove_sequence = 0; | |
349 | INIT_LIST_HEAD(&cwq->worklist); | |
350 | init_waitqueue_head(&cwq->more_work); | |
351 | init_waitqueue_head(&cwq->work_done); | |
352 | ||
353 | if (is_single_threaded(wq)) | |
354 | p = kthread_create(worker_thread, cwq, "%s", wq->name); | |
355 | else | |
356 | p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); | |
357 | if (IS_ERR(p)) | |
358 | return NULL; | |
359 | cwq->thread = p; | |
360 | return p; | |
361 | } | |
362 | ||
363 | struct workqueue_struct *__create_workqueue(const char *name, | |
364 | int singlethread) | |
365 | { | |
366 | int cpu, destroy = 0; | |
367 | struct workqueue_struct *wq; | |
368 | struct task_struct *p; | |
369 | ||
dd392710 | 370 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
1da177e4 LT |
371 | if (!wq) |
372 | return NULL; | |
1da177e4 | 373 | |
89ada679 | 374 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); |
676121fc BC |
375 | if (!wq->cpu_wq) { |
376 | kfree(wq); | |
377 | return NULL; | |
378 | } | |
379 | ||
1da177e4 | 380 | wq->name = name; |
9b41ea72 | 381 | mutex_lock(&workqueue_mutex); |
1da177e4 LT |
382 | if (singlethread) { |
383 | INIT_LIST_HEAD(&wq->list); | |
f756d5e2 | 384 | p = create_workqueue_thread(wq, singlethread_cpu); |
1da177e4 LT |
385 | if (!p) |
386 | destroy = 1; | |
387 | else | |
388 | wake_up_process(p); | |
389 | } else { | |
1da177e4 | 390 | list_add(&wq->list, &workqueues); |
1da177e4 LT |
391 | for_each_online_cpu(cpu) { |
392 | p = create_workqueue_thread(wq, cpu); | |
393 | if (p) { | |
394 | kthread_bind(p, cpu); | |
395 | wake_up_process(p); | |
396 | } else | |
397 | destroy = 1; | |
398 | } | |
399 | } | |
9b41ea72 | 400 | mutex_unlock(&workqueue_mutex); |
1da177e4 LT |
401 | |
402 | /* | |
403 | * Was there any error during startup? If yes then clean up: | |
404 | */ | |
405 | if (destroy) { | |
406 | destroy_workqueue(wq); | |
407 | wq = NULL; | |
408 | } | |
409 | return wq; | |
410 | } | |
ae90dd5d | 411 | EXPORT_SYMBOL_GPL(__create_workqueue); |
1da177e4 LT |
412 | |
413 | static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) | |
414 | { | |
415 | struct cpu_workqueue_struct *cwq; | |
416 | unsigned long flags; | |
417 | struct task_struct *p; | |
418 | ||
89ada679 | 419 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 LT |
420 | spin_lock_irqsave(&cwq->lock, flags); |
421 | p = cwq->thread; | |
422 | cwq->thread = NULL; | |
423 | spin_unlock_irqrestore(&cwq->lock, flags); | |
424 | if (p) | |
425 | kthread_stop(p); | |
426 | } | |
427 | ||
0fcb78c2 REB |
428 | /** |
429 | * destroy_workqueue - safely terminate a workqueue | |
430 | * @wq: target workqueue | |
431 | * | |
432 | * Safely destroy a workqueue. All work currently pending will be done first. | |
433 | */ | |
1da177e4 LT |
434 | void destroy_workqueue(struct workqueue_struct *wq) |
435 | { | |
436 | int cpu; | |
437 | ||
438 | flush_workqueue(wq); | |
439 | ||
440 | /* We don't need the distraction of CPUs appearing and vanishing. */ | |
9b41ea72 | 441 | mutex_lock(&workqueue_mutex); |
1da177e4 | 442 | if (is_single_threaded(wq)) |
f756d5e2 | 443 | cleanup_workqueue_thread(wq, singlethread_cpu); |
1da177e4 LT |
444 | else { |
445 | for_each_online_cpu(cpu) | |
446 | cleanup_workqueue_thread(wq, cpu); | |
1da177e4 | 447 | list_del(&wq->list); |
1da177e4 | 448 | } |
9b41ea72 | 449 | mutex_unlock(&workqueue_mutex); |
89ada679 | 450 | free_percpu(wq->cpu_wq); |
1da177e4 LT |
451 | kfree(wq); |
452 | } | |
ae90dd5d | 453 | EXPORT_SYMBOL_GPL(destroy_workqueue); |
1da177e4 LT |
454 | |
455 | static struct workqueue_struct *keventd_wq; | |
456 | ||
0fcb78c2 REB |
457 | /** |
458 | * schedule_work - put work task in global workqueue | |
459 | * @work: job to be done | |
460 | * | |
461 | * This puts a job in the kernel-global workqueue. | |
462 | */ | |
1da177e4 LT |
463 | int fastcall schedule_work(struct work_struct *work) |
464 | { | |
465 | return queue_work(keventd_wq, work); | |
466 | } | |
ae90dd5d | 467 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 468 | |
0fcb78c2 REB |
469 | /** |
470 | * schedule_delayed_work - put work task in global workqueue after delay | |
471 | * @work: job to be done | |
472 | * @delay: number of jiffies to wait | |
473 | * | |
474 | * After waiting for a given time this puts a job in the kernel-global | |
475 | * workqueue. | |
476 | */ | |
1da177e4 LT |
477 | int fastcall schedule_delayed_work(struct work_struct *work, unsigned long delay) |
478 | { | |
479 | return queue_delayed_work(keventd_wq, work, delay); | |
480 | } | |
ae90dd5d | 481 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 482 | |
0fcb78c2 REB |
483 | /** |
484 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
485 | * @cpu: cpu to use | |
486 | * @work: job to be done | |
487 | * @delay: number of jiffies to wait | |
488 | * | |
489 | * After waiting for a given time this puts a job in the kernel-global | |
490 | * workqueue on the specified CPU. | |
491 | */ | |
1da177e4 LT |
492 | int schedule_delayed_work_on(int cpu, |
493 | struct work_struct *work, unsigned long delay) | |
494 | { | |
7a6bc1cd | 495 | return queue_delayed_work_on(cpu, keventd_wq, work, delay); |
1da177e4 | 496 | } |
ae90dd5d | 497 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 498 | |
b6136773 AM |
499 | /** |
500 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
501 | * @func: the function to call | |
502 | * @info: a pointer to pass to func() | |
503 | * | |
504 | * Returns zero on success. | |
505 | * Returns -ve errno on failure. | |
506 | * | |
507 | * Appears to be racy against CPU hotplug. | |
508 | * | |
509 | * schedule_on_each_cpu() is very slow. | |
510 | */ | |
511 | int schedule_on_each_cpu(void (*func)(void *info), void *info) | |
15316ba8 CL |
512 | { |
513 | int cpu; | |
b6136773 | 514 | struct work_struct *works; |
15316ba8 | 515 | |
b6136773 AM |
516 | works = alloc_percpu(struct work_struct); |
517 | if (!works) | |
15316ba8 | 518 | return -ENOMEM; |
b6136773 | 519 | |
9b41ea72 | 520 | mutex_lock(&workqueue_mutex); |
15316ba8 | 521 | for_each_online_cpu(cpu) { |
b6136773 | 522 | INIT_WORK(per_cpu_ptr(works, cpu), func, info); |
15316ba8 | 523 | __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), |
b6136773 | 524 | per_cpu_ptr(works, cpu)); |
15316ba8 | 525 | } |
9b41ea72 | 526 | mutex_unlock(&workqueue_mutex); |
15316ba8 | 527 | flush_workqueue(keventd_wq); |
b6136773 | 528 | free_percpu(works); |
15316ba8 CL |
529 | return 0; |
530 | } | |
531 | ||
1da177e4 LT |
532 | void flush_scheduled_work(void) |
533 | { | |
534 | flush_workqueue(keventd_wq); | |
535 | } | |
ae90dd5d | 536 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 LT |
537 | |
538 | /** | |
539 | * cancel_rearming_delayed_workqueue - reliably kill off a delayed | |
540 | * work whose handler rearms the delayed work. | |
541 | * @wq: the controlling workqueue structure | |
542 | * @work: the delayed work struct | |
543 | */ | |
81ddef77 JB |
544 | void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, |
545 | struct work_struct *work) | |
1da177e4 LT |
546 | { |
547 | while (!cancel_delayed_work(work)) | |
548 | flush_workqueue(wq); | |
549 | } | |
81ddef77 | 550 | EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); |
1da177e4 LT |
551 | |
552 | /** | |
553 | * cancel_rearming_delayed_work - reliably kill off a delayed keventd | |
554 | * work whose handler rearms the delayed work. | |
555 | * @work: the delayed work struct | |
556 | */ | |
557 | void cancel_rearming_delayed_work(struct work_struct *work) | |
558 | { | |
559 | cancel_rearming_delayed_workqueue(keventd_wq, work); | |
560 | } | |
561 | EXPORT_SYMBOL(cancel_rearming_delayed_work); | |
562 | ||
1fa44eca JB |
563 | /** |
564 | * execute_in_process_context - reliably execute the routine with user context | |
565 | * @fn: the function to execute | |
566 | * @data: data to pass to the function | |
567 | * @ew: guaranteed storage for the execute work structure (must | |
568 | * be available when the work executes) | |
569 | * | |
570 | * Executes the function immediately if process context is available, | |
571 | * otherwise schedules the function for delayed execution. | |
572 | * | |
573 | * Returns: 0 - function was executed | |
574 | * 1 - function was scheduled for execution | |
575 | */ | |
576 | int execute_in_process_context(void (*fn)(void *data), void *data, | |
577 | struct execute_work *ew) | |
578 | { | |
579 | if (!in_interrupt()) { | |
580 | fn(data); | |
581 | return 0; | |
582 | } | |
583 | ||
584 | INIT_WORK(&ew->work, fn, data); | |
585 | schedule_work(&ew->work); | |
586 | ||
587 | return 1; | |
588 | } | |
589 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
590 | ||
1da177e4 LT |
591 | int keventd_up(void) |
592 | { | |
593 | return keventd_wq != NULL; | |
594 | } | |
595 | ||
596 | int current_is_keventd(void) | |
597 | { | |
598 | struct cpu_workqueue_struct *cwq; | |
599 | int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ | |
600 | int ret = 0; | |
601 | ||
602 | BUG_ON(!keventd_wq); | |
603 | ||
89ada679 | 604 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
605 | if (current == cwq->thread) |
606 | ret = 1; | |
607 | ||
608 | return ret; | |
609 | ||
610 | } | |
611 | ||
612 | #ifdef CONFIG_HOTPLUG_CPU | |
613 | /* Take the work from this (downed) CPU. */ | |
614 | static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) | |
615 | { | |
89ada679 | 616 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
626ab0e6 | 617 | struct list_head list; |
1da177e4 LT |
618 | struct work_struct *work; |
619 | ||
620 | spin_lock_irq(&cwq->lock); | |
626ab0e6 | 621 | list_replace_init(&cwq->worklist, &list); |
1da177e4 LT |
622 | |
623 | while (!list_empty(&list)) { | |
624 | printk("Taking work for %s\n", wq->name); | |
625 | work = list_entry(list.next,struct work_struct,entry); | |
626 | list_del(&work->entry); | |
89ada679 | 627 | __queue_work(per_cpu_ptr(wq->cpu_wq, smp_processor_id()), work); |
1da177e4 LT |
628 | } |
629 | spin_unlock_irq(&cwq->lock); | |
630 | } | |
631 | ||
632 | /* We're holding the cpucontrol mutex here */ | |
9c7b216d | 633 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, |
1da177e4 LT |
634 | unsigned long action, |
635 | void *hcpu) | |
636 | { | |
637 | unsigned int hotcpu = (unsigned long)hcpu; | |
638 | struct workqueue_struct *wq; | |
639 | ||
640 | switch (action) { | |
641 | case CPU_UP_PREPARE: | |
9b41ea72 | 642 | mutex_lock(&workqueue_mutex); |
1da177e4 LT |
643 | /* Create a new workqueue thread for it. */ |
644 | list_for_each_entry(wq, &workqueues, list) { | |
230649da | 645 | if (!create_workqueue_thread(wq, hotcpu)) { |
1da177e4 LT |
646 | printk("workqueue for %i failed\n", hotcpu); |
647 | return NOTIFY_BAD; | |
648 | } | |
649 | } | |
650 | break; | |
651 | ||
652 | case CPU_ONLINE: | |
653 | /* Kick off worker threads. */ | |
654 | list_for_each_entry(wq, &workqueues, list) { | |
89ada679 CL |
655 | struct cpu_workqueue_struct *cwq; |
656 | ||
657 | cwq = per_cpu_ptr(wq->cpu_wq, hotcpu); | |
658 | kthread_bind(cwq->thread, hotcpu); | |
659 | wake_up_process(cwq->thread); | |
1da177e4 | 660 | } |
9b41ea72 | 661 | mutex_unlock(&workqueue_mutex); |
1da177e4 LT |
662 | break; |
663 | ||
664 | case CPU_UP_CANCELED: | |
665 | list_for_each_entry(wq, &workqueues, list) { | |
fc75cdfa HC |
666 | if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread) |
667 | continue; | |
1da177e4 | 668 | /* Unbind so it can run. */ |
89ada679 | 669 | kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread, |
a4c4af7c | 670 | any_online_cpu(cpu_online_map)); |
1da177e4 LT |
671 | cleanup_workqueue_thread(wq, hotcpu); |
672 | } | |
9b41ea72 AM |
673 | mutex_unlock(&workqueue_mutex); |
674 | break; | |
675 | ||
676 | case CPU_DOWN_PREPARE: | |
677 | mutex_lock(&workqueue_mutex); | |
678 | break; | |
679 | ||
680 | case CPU_DOWN_FAILED: | |
681 | mutex_unlock(&workqueue_mutex); | |
1da177e4 LT |
682 | break; |
683 | ||
684 | case CPU_DEAD: | |
685 | list_for_each_entry(wq, &workqueues, list) | |
686 | cleanup_workqueue_thread(wq, hotcpu); | |
687 | list_for_each_entry(wq, &workqueues, list) | |
688 | take_over_work(wq, hotcpu); | |
9b41ea72 | 689 | mutex_unlock(&workqueue_mutex); |
1da177e4 LT |
690 | break; |
691 | } | |
692 | ||
693 | return NOTIFY_OK; | |
694 | } | |
695 | #endif | |
696 | ||
697 | void init_workqueues(void) | |
698 | { | |
f756d5e2 | 699 | singlethread_cpu = first_cpu(cpu_possible_map); |
1da177e4 LT |
700 | hotcpu_notifier(workqueue_cpu_callback, 0); |
701 | keventd_wq = create_workqueue("events"); | |
702 | BUG_ON(!keventd_wq); | |
703 | } | |
704 |