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> | |
e1f8e874 | 12 | * Andrew Morton |
1da177e4 LT |
13 | * Kai Petzke <wpp@marie.physik.tu-berlin.de> |
14 | * Theodore Ts'o <tytso@mit.edu> | |
89ada679 | 15 | * |
cde53535 | 16 | * Made to use alloc_percpu by Christoph Lameter. |
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> |
341a5958 | 32 | #include <linux/freezer.h> |
d5abe669 PZ |
33 | #include <linux/kallsyms.h> |
34 | #include <linux/debug_locks.h> | |
4e6045f1 | 35 | #include <linux/lockdep.h> |
e1d8aa9f | 36 | #include <trace/workqueue.h> |
1da177e4 LT |
37 | |
38 | /* | |
f756d5e2 NL |
39 | * The per-CPU workqueue (if single thread, we always use the first |
40 | * possible cpu). | |
1da177e4 LT |
41 | */ |
42 | struct cpu_workqueue_struct { | |
43 | ||
44 | spinlock_t lock; | |
45 | ||
1da177e4 LT |
46 | struct list_head worklist; |
47 | wait_queue_head_t more_work; | |
3af24433 | 48 | struct work_struct *current_work; |
1da177e4 LT |
49 | |
50 | struct workqueue_struct *wq; | |
36c8b586 | 51 | struct task_struct *thread; |
1da177e4 LT |
52 | } ____cacheline_aligned; |
53 | ||
54 | /* | |
55 | * The externally visible workqueue abstraction is an array of | |
56 | * per-CPU workqueues: | |
57 | */ | |
58 | struct workqueue_struct { | |
89ada679 | 59 | struct cpu_workqueue_struct *cpu_wq; |
cce1a165 | 60 | struct list_head list; |
1da177e4 | 61 | const char *name; |
cce1a165 | 62 | int singlethread; |
319c2a98 | 63 | int freezeable; /* Freeze threads during suspend */ |
0d557dc9 | 64 | int rt; |
4e6045f1 JB |
65 | #ifdef CONFIG_LOCKDEP |
66 | struct lockdep_map lockdep_map; | |
67 | #endif | |
1da177e4 LT |
68 | }; |
69 | ||
95402b38 GS |
70 | /* Serializes the accesses to the list of workqueues. */ |
71 | static DEFINE_SPINLOCK(workqueue_lock); | |
1da177e4 LT |
72 | static LIST_HEAD(workqueues); |
73 | ||
3af24433 | 74 | static int singlethread_cpu __read_mostly; |
e7577c50 | 75 | static const struct cpumask *cpu_singlethread_map __read_mostly; |
14441960 ON |
76 | /* |
77 | * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD | |
78 | * flushes cwq->worklist. This means that flush_workqueue/wait_on_work | |
79 | * which comes in between can't use for_each_online_cpu(). We could | |
80 | * use cpu_possible_map, the cpumask below is more a documentation | |
81 | * than optimization. | |
82 | */ | |
e7577c50 | 83 | static cpumask_var_t cpu_populated_map __read_mostly; |
f756d5e2 | 84 | |
1da177e4 | 85 | /* If it's single threaded, it isn't in the list of workqueues. */ |
6cc88bc4 | 86 | static inline int is_wq_single_threaded(struct workqueue_struct *wq) |
1da177e4 | 87 | { |
cce1a165 | 88 | return wq->singlethread; |
1da177e4 LT |
89 | } |
90 | ||
e7577c50 | 91 | static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq) |
b1f4ec17 | 92 | { |
6cc88bc4 | 93 | return is_wq_single_threaded(wq) |
e7577c50 | 94 | ? cpu_singlethread_map : cpu_populated_map; |
b1f4ec17 ON |
95 | } |
96 | ||
a848e3b6 ON |
97 | static |
98 | struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu) | |
99 | { | |
6cc88bc4 | 100 | if (unlikely(is_wq_single_threaded(wq))) |
a848e3b6 ON |
101 | cpu = singlethread_cpu; |
102 | return per_cpu_ptr(wq->cpu_wq, cpu); | |
103 | } | |
104 | ||
4594bf15 DH |
105 | /* |
106 | * Set the workqueue on which a work item is to be run | |
107 | * - Must *only* be called if the pending flag is set | |
108 | */ | |
ed7c0fee ON |
109 | static inline void set_wq_data(struct work_struct *work, |
110 | struct cpu_workqueue_struct *cwq) | |
365970a1 | 111 | { |
4594bf15 DH |
112 | unsigned long new; |
113 | ||
114 | BUG_ON(!work_pending(work)); | |
365970a1 | 115 | |
ed7c0fee | 116 | new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING); |
a08727ba LT |
117 | new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); |
118 | atomic_long_set(&work->data, new); | |
365970a1 DH |
119 | } |
120 | ||
ed7c0fee ON |
121 | static inline |
122 | struct cpu_workqueue_struct *get_wq_data(struct work_struct *work) | |
365970a1 | 123 | { |
a08727ba | 124 | return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); |
365970a1 DH |
125 | } |
126 | ||
e1d8aa9f FW |
127 | DEFINE_TRACE(workqueue_insertion); |
128 | ||
b89deed3 | 129 | static void insert_work(struct cpu_workqueue_struct *cwq, |
1a4d9b0a | 130 | struct work_struct *work, struct list_head *head) |
b89deed3 | 131 | { |
e1d8aa9f FW |
132 | trace_workqueue_insertion(cwq->thread, work); |
133 | ||
b89deed3 | 134 | set_wq_data(work, cwq); |
6e84d644 ON |
135 | /* |
136 | * Ensure that we get the right work->data if we see the | |
137 | * result of list_add() below, see try_to_grab_pending(). | |
138 | */ | |
139 | smp_wmb(); | |
1a4d9b0a | 140 | list_add_tail(&work->entry, head); |
b89deed3 ON |
141 | wake_up(&cwq->more_work); |
142 | } | |
143 | ||
1da177e4 LT |
144 | static void __queue_work(struct cpu_workqueue_struct *cwq, |
145 | struct work_struct *work) | |
146 | { | |
147 | unsigned long flags; | |
148 | ||
149 | spin_lock_irqsave(&cwq->lock, flags); | |
1a4d9b0a | 150 | insert_work(cwq, work, &cwq->worklist); |
1da177e4 LT |
151 | spin_unlock_irqrestore(&cwq->lock, flags); |
152 | } | |
153 | ||
0fcb78c2 REB |
154 | /** |
155 | * queue_work - queue work on a workqueue | |
156 | * @wq: workqueue to use | |
157 | * @work: work to queue | |
158 | * | |
057647fc | 159 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 | 160 | * |
00dfcaf7 ON |
161 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
162 | * it can be processed by another CPU. | |
1da177e4 | 163 | */ |
7ad5b3a5 | 164 | int queue_work(struct workqueue_struct *wq, struct work_struct *work) |
1da177e4 | 165 | { |
ef1ca236 ON |
166 | int ret; |
167 | ||
168 | ret = queue_work_on(get_cpu(), wq, work); | |
169 | put_cpu(); | |
170 | ||
1da177e4 LT |
171 | return ret; |
172 | } | |
ae90dd5d | 173 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 174 | |
c1a220e7 ZR |
175 | /** |
176 | * queue_work_on - queue work on specific cpu | |
177 | * @cpu: CPU number to execute work on | |
178 | * @wq: workqueue to use | |
179 | * @work: work to queue | |
180 | * | |
181 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
182 | * | |
183 | * We queue the work to a specific CPU, the caller must ensure it | |
184 | * can't go away. | |
185 | */ | |
186 | int | |
187 | queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) | |
188 | { | |
189 | int ret = 0; | |
190 | ||
191 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | |
192 | BUG_ON(!list_empty(&work->entry)); | |
193 | __queue_work(wq_per_cpu(wq, cpu), work); | |
194 | ret = 1; | |
195 | } | |
196 | return ret; | |
197 | } | |
198 | EXPORT_SYMBOL_GPL(queue_work_on); | |
199 | ||
6d141c3f | 200 | static void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 201 | { |
52bad64d | 202 | struct delayed_work *dwork = (struct delayed_work *)__data; |
ed7c0fee ON |
203 | struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
204 | struct workqueue_struct *wq = cwq->wq; | |
1da177e4 | 205 | |
a848e3b6 | 206 | __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work); |
1da177e4 LT |
207 | } |
208 | ||
0fcb78c2 REB |
209 | /** |
210 | * queue_delayed_work - queue work on a workqueue after delay | |
211 | * @wq: workqueue to use | |
af9997e4 | 212 | * @dwork: delayable work to queue |
0fcb78c2 REB |
213 | * @delay: number of jiffies to wait before queueing |
214 | * | |
057647fc | 215 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 216 | */ |
7ad5b3a5 | 217 | int queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 218 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 219 | { |
52bad64d | 220 | if (delay == 0) |
63bc0362 | 221 | return queue_work(wq, &dwork->work); |
1da177e4 | 222 | |
63bc0362 | 223 | return queue_delayed_work_on(-1, wq, dwork, delay); |
1da177e4 | 224 | } |
ae90dd5d | 225 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 226 | |
0fcb78c2 REB |
227 | /** |
228 | * queue_delayed_work_on - queue work on specific CPU after delay | |
229 | * @cpu: CPU number to execute work on | |
230 | * @wq: workqueue to use | |
af9997e4 | 231 | * @dwork: work to queue |
0fcb78c2 REB |
232 | * @delay: number of jiffies to wait before queueing |
233 | * | |
057647fc | 234 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 235 | */ |
7a6bc1cd | 236 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 237 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
238 | { |
239 | int ret = 0; | |
52bad64d DH |
240 | struct timer_list *timer = &dwork->timer; |
241 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 242 | |
a08727ba | 243 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
7a6bc1cd VP |
244 | BUG_ON(timer_pending(timer)); |
245 | BUG_ON(!list_empty(&work->entry)); | |
246 | ||
8a3e77cc AL |
247 | timer_stats_timer_set_start_info(&dwork->timer); |
248 | ||
ed7c0fee | 249 | /* This stores cwq for the moment, for the timer_fn */ |
a848e3b6 | 250 | set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id())); |
7a6bc1cd | 251 | timer->expires = jiffies + delay; |
52bad64d | 252 | timer->data = (unsigned long)dwork; |
7a6bc1cd | 253 | timer->function = delayed_work_timer_fn; |
63bc0362 ON |
254 | |
255 | if (unlikely(cpu >= 0)) | |
256 | add_timer_on(timer, cpu); | |
257 | else | |
258 | add_timer(timer); | |
7a6bc1cd VP |
259 | ret = 1; |
260 | } | |
261 | return ret; | |
262 | } | |
ae90dd5d | 263 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 264 | |
e1d8aa9f FW |
265 | DEFINE_TRACE(workqueue_execution); |
266 | ||
858119e1 | 267 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 268 | { |
f293ea92 | 269 | spin_lock_irq(&cwq->lock); |
1da177e4 LT |
270 | while (!list_empty(&cwq->worklist)) { |
271 | struct work_struct *work = list_entry(cwq->worklist.next, | |
272 | struct work_struct, entry); | |
6bb49e59 | 273 | work_func_t f = work->func; |
4e6045f1 JB |
274 | #ifdef CONFIG_LOCKDEP |
275 | /* | |
276 | * It is permissible to free the struct work_struct | |
277 | * from inside the function that is called from it, | |
278 | * this we need to take into account for lockdep too. | |
279 | * To avoid bogus "held lock freed" warnings as well | |
280 | * as problems when looking into work->lockdep_map, | |
281 | * make a copy and use that here. | |
282 | */ | |
283 | struct lockdep_map lockdep_map = work->lockdep_map; | |
284 | #endif | |
e1d8aa9f | 285 | trace_workqueue_execution(cwq->thread, work); |
b89deed3 | 286 | cwq->current_work = work; |
1da177e4 | 287 | list_del_init(cwq->worklist.next); |
f293ea92 | 288 | spin_unlock_irq(&cwq->lock); |
1da177e4 | 289 | |
365970a1 | 290 | BUG_ON(get_wq_data(work) != cwq); |
23b2e599 | 291 | work_clear_pending(work); |
3295f0ef IM |
292 | lock_map_acquire(&cwq->wq->lockdep_map); |
293 | lock_map_acquire(&lockdep_map); | |
65f27f38 | 294 | f(work); |
3295f0ef IM |
295 | lock_map_release(&lockdep_map); |
296 | lock_map_release(&cwq->wq->lockdep_map); | |
1da177e4 | 297 | |
d5abe669 PZ |
298 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
299 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
300 | "%s/0x%08x/%d\n", | |
301 | current->comm, preempt_count(), | |
ba25f9dc | 302 | task_pid_nr(current)); |
d5abe669 PZ |
303 | printk(KERN_ERR " last function: "); |
304 | print_symbol("%s\n", (unsigned long)f); | |
305 | debug_show_held_locks(current); | |
306 | dump_stack(); | |
307 | } | |
308 | ||
f293ea92 | 309 | spin_lock_irq(&cwq->lock); |
b89deed3 | 310 | cwq->current_work = NULL; |
1da177e4 | 311 | } |
f293ea92 | 312 | spin_unlock_irq(&cwq->lock); |
1da177e4 LT |
313 | } |
314 | ||
315 | static int worker_thread(void *__cwq) | |
316 | { | |
317 | struct cpu_workqueue_struct *cwq = __cwq; | |
3af24433 | 318 | DEFINE_WAIT(wait); |
1da177e4 | 319 | |
83144186 RW |
320 | if (cwq->wq->freezeable) |
321 | set_freezable(); | |
1da177e4 LT |
322 | |
323 | set_user_nice(current, -5); | |
1da177e4 | 324 | |
3af24433 | 325 | for (;;) { |
3af24433 | 326 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
14441960 ON |
327 | if (!freezing(current) && |
328 | !kthread_should_stop() && | |
329 | list_empty(&cwq->worklist)) | |
1da177e4 | 330 | schedule(); |
3af24433 ON |
331 | finish_wait(&cwq->more_work, &wait); |
332 | ||
85f4186a ON |
333 | try_to_freeze(); |
334 | ||
14441960 | 335 | if (kthread_should_stop()) |
3af24433 | 336 | break; |
1da177e4 | 337 | |
3af24433 | 338 | run_workqueue(cwq); |
1da177e4 | 339 | } |
3af24433 | 340 | |
1da177e4 LT |
341 | return 0; |
342 | } | |
343 | ||
fc2e4d70 ON |
344 | struct wq_barrier { |
345 | struct work_struct work; | |
346 | struct completion done; | |
347 | }; | |
348 | ||
349 | static void wq_barrier_func(struct work_struct *work) | |
350 | { | |
351 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
352 | complete(&barr->done); | |
353 | } | |
354 | ||
83c22520 | 355 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
1a4d9b0a | 356 | struct wq_barrier *barr, struct list_head *head) |
fc2e4d70 ON |
357 | { |
358 | INIT_WORK(&barr->work, wq_barrier_func); | |
359 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); | |
360 | ||
361 | init_completion(&barr->done); | |
83c22520 | 362 | |
1a4d9b0a | 363 | insert_work(cwq, &barr->work, head); |
fc2e4d70 ON |
364 | } |
365 | ||
14441960 | 366 | static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 367 | { |
2355b70f LJ |
368 | int active = 0; |
369 | struct wq_barrier barr; | |
1da177e4 | 370 | |
2355b70f | 371 | WARN_ON(cwq->thread == current); |
1da177e4 | 372 | |
2355b70f LJ |
373 | spin_lock_irq(&cwq->lock); |
374 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
375 | insert_wq_barrier(cwq, &barr, &cwq->worklist); | |
376 | active = 1; | |
1da177e4 | 377 | } |
2355b70f LJ |
378 | spin_unlock_irq(&cwq->lock); |
379 | ||
380 | if (active) | |
381 | wait_for_completion(&barr.done); | |
14441960 ON |
382 | |
383 | return active; | |
1da177e4 LT |
384 | } |
385 | ||
0fcb78c2 | 386 | /** |
1da177e4 | 387 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 388 | * @wq: workqueue to flush |
1da177e4 LT |
389 | * |
390 | * Forces execution of the workqueue and blocks until its completion. | |
391 | * This is typically used in driver shutdown handlers. | |
392 | * | |
fc2e4d70 ON |
393 | * We sleep until all works which were queued on entry have been handled, |
394 | * but we are not livelocked by new incoming ones. | |
1da177e4 LT |
395 | * |
396 | * This function used to run the workqueues itself. Now we just wait for the | |
397 | * helper threads to do it. | |
398 | */ | |
7ad5b3a5 | 399 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 400 | { |
e7577c50 | 401 | const struct cpumask *cpu_map = wq_cpu_map(wq); |
cce1a165 | 402 | int cpu; |
1da177e4 | 403 | |
b1f4ec17 | 404 | might_sleep(); |
3295f0ef IM |
405 | lock_map_acquire(&wq->lockdep_map); |
406 | lock_map_release(&wq->lockdep_map); | |
aa85ea5b | 407 | for_each_cpu(cpu, cpu_map) |
b1f4ec17 | 408 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
1da177e4 | 409 | } |
ae90dd5d | 410 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 411 | |
db700897 ON |
412 | /** |
413 | * flush_work - block until a work_struct's callback has terminated | |
414 | * @work: the work which is to be flushed | |
415 | * | |
a67da70d ON |
416 | * Returns false if @work has already terminated. |
417 | * | |
db700897 ON |
418 | * It is expected that, prior to calling flush_work(), the caller has |
419 | * arranged for the work to not be requeued, otherwise it doesn't make | |
420 | * sense to use this function. | |
421 | */ | |
422 | int flush_work(struct work_struct *work) | |
423 | { | |
424 | struct cpu_workqueue_struct *cwq; | |
425 | struct list_head *prev; | |
426 | struct wq_barrier barr; | |
427 | ||
428 | might_sleep(); | |
429 | cwq = get_wq_data(work); | |
430 | if (!cwq) | |
431 | return 0; | |
432 | ||
3295f0ef IM |
433 | lock_map_acquire(&cwq->wq->lockdep_map); |
434 | lock_map_release(&cwq->wq->lockdep_map); | |
a67da70d | 435 | |
db700897 ON |
436 | prev = NULL; |
437 | spin_lock_irq(&cwq->lock); | |
438 | if (!list_empty(&work->entry)) { | |
439 | /* | |
440 | * See the comment near try_to_grab_pending()->smp_rmb(). | |
441 | * If it was re-queued under us we are not going to wait. | |
442 | */ | |
443 | smp_rmb(); | |
444 | if (unlikely(cwq != get_wq_data(work))) | |
445 | goto out; | |
446 | prev = &work->entry; | |
447 | } else { | |
448 | if (cwq->current_work != work) | |
449 | goto out; | |
450 | prev = &cwq->worklist; | |
451 | } | |
452 | insert_wq_barrier(cwq, &barr, prev->next); | |
453 | out: | |
454 | spin_unlock_irq(&cwq->lock); | |
455 | if (!prev) | |
456 | return 0; | |
457 | ||
458 | wait_for_completion(&barr.done); | |
459 | return 1; | |
460 | } | |
461 | EXPORT_SYMBOL_GPL(flush_work); | |
462 | ||
6e84d644 | 463 | /* |
1f1f642e | 464 | * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, |
6e84d644 ON |
465 | * so this work can't be re-armed in any way. |
466 | */ | |
467 | static int try_to_grab_pending(struct work_struct *work) | |
468 | { | |
469 | struct cpu_workqueue_struct *cwq; | |
1f1f642e | 470 | int ret = -1; |
6e84d644 ON |
471 | |
472 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) | |
1f1f642e | 473 | return 0; |
6e84d644 ON |
474 | |
475 | /* | |
476 | * The queueing is in progress, or it is already queued. Try to | |
477 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
478 | */ | |
479 | ||
480 | cwq = get_wq_data(work); | |
481 | if (!cwq) | |
482 | return ret; | |
483 | ||
484 | spin_lock_irq(&cwq->lock); | |
485 | if (!list_empty(&work->entry)) { | |
486 | /* | |
487 | * This work is queued, but perhaps we locked the wrong cwq. | |
488 | * In that case we must see the new value after rmb(), see | |
489 | * insert_work()->wmb(). | |
490 | */ | |
491 | smp_rmb(); | |
492 | if (cwq == get_wq_data(work)) { | |
493 | list_del_init(&work->entry); | |
494 | ret = 1; | |
495 | } | |
496 | } | |
497 | spin_unlock_irq(&cwq->lock); | |
498 | ||
499 | return ret; | |
500 | } | |
501 | ||
502 | static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | |
b89deed3 ON |
503 | struct work_struct *work) |
504 | { | |
505 | struct wq_barrier barr; | |
506 | int running = 0; | |
507 | ||
508 | spin_lock_irq(&cwq->lock); | |
509 | if (unlikely(cwq->current_work == work)) { | |
1a4d9b0a | 510 | insert_wq_barrier(cwq, &barr, cwq->worklist.next); |
b89deed3 ON |
511 | running = 1; |
512 | } | |
513 | spin_unlock_irq(&cwq->lock); | |
514 | ||
3af24433 | 515 | if (unlikely(running)) |
b89deed3 | 516 | wait_for_completion(&barr.done); |
b89deed3 ON |
517 | } |
518 | ||
6e84d644 | 519 | static void wait_on_work(struct work_struct *work) |
b89deed3 ON |
520 | { |
521 | struct cpu_workqueue_struct *cwq; | |
28e53bdd | 522 | struct workqueue_struct *wq; |
e7577c50 | 523 | const struct cpumask *cpu_map; |
b1f4ec17 | 524 | int cpu; |
b89deed3 | 525 | |
f293ea92 ON |
526 | might_sleep(); |
527 | ||
3295f0ef IM |
528 | lock_map_acquire(&work->lockdep_map); |
529 | lock_map_release(&work->lockdep_map); | |
4e6045f1 | 530 | |
b89deed3 | 531 | cwq = get_wq_data(work); |
b89deed3 | 532 | if (!cwq) |
3af24433 | 533 | return; |
b89deed3 | 534 | |
28e53bdd ON |
535 | wq = cwq->wq; |
536 | cpu_map = wq_cpu_map(wq); | |
537 | ||
aa85ea5b | 538 | for_each_cpu(cpu, cpu_map) |
6e84d644 ON |
539 | wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
540 | } | |
541 | ||
1f1f642e ON |
542 | static int __cancel_work_timer(struct work_struct *work, |
543 | struct timer_list* timer) | |
544 | { | |
545 | int ret; | |
546 | ||
547 | do { | |
548 | ret = (timer && likely(del_timer(timer))); | |
549 | if (!ret) | |
550 | ret = try_to_grab_pending(work); | |
551 | wait_on_work(work); | |
552 | } while (unlikely(ret < 0)); | |
553 | ||
554 | work_clear_pending(work); | |
555 | return ret; | |
556 | } | |
557 | ||
6e84d644 ON |
558 | /** |
559 | * cancel_work_sync - block until a work_struct's callback has terminated | |
560 | * @work: the work which is to be flushed | |
561 | * | |
1f1f642e ON |
562 | * Returns true if @work was pending. |
563 | * | |
6e84d644 ON |
564 | * cancel_work_sync() will cancel the work if it is queued. If the work's |
565 | * callback appears to be running, cancel_work_sync() will block until it | |
566 | * has completed. | |
567 | * | |
568 | * It is possible to use this function if the work re-queues itself. It can | |
569 | * cancel the work even if it migrates to another workqueue, however in that | |
570 | * case it only guarantees that work->func() has completed on the last queued | |
571 | * workqueue. | |
572 | * | |
573 | * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not | |
574 | * pending, otherwise it goes into a busy-wait loop until the timer expires. | |
575 | * | |
576 | * The caller must ensure that workqueue_struct on which this work was last | |
577 | * queued can't be destroyed before this function returns. | |
578 | */ | |
1f1f642e | 579 | int cancel_work_sync(struct work_struct *work) |
6e84d644 | 580 | { |
1f1f642e | 581 | return __cancel_work_timer(work, NULL); |
b89deed3 | 582 | } |
28e53bdd | 583 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 584 | |
6e84d644 | 585 | /** |
f5a421a4 | 586 | * cancel_delayed_work_sync - reliably kill off a delayed work. |
6e84d644 ON |
587 | * @dwork: the delayed work struct |
588 | * | |
1f1f642e ON |
589 | * Returns true if @dwork was pending. |
590 | * | |
6e84d644 ON |
591 | * It is possible to use this function if @dwork rearms itself via queue_work() |
592 | * or queue_delayed_work(). See also the comment for cancel_work_sync(). | |
593 | */ | |
1f1f642e | 594 | int cancel_delayed_work_sync(struct delayed_work *dwork) |
6e84d644 | 595 | { |
1f1f642e | 596 | return __cancel_work_timer(&dwork->work, &dwork->timer); |
6e84d644 | 597 | } |
f5a421a4 | 598 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 599 | |
6e84d644 | 600 | static struct workqueue_struct *keventd_wq __read_mostly; |
1da177e4 | 601 | |
0fcb78c2 REB |
602 | /** |
603 | * schedule_work - put work task in global workqueue | |
604 | * @work: job to be done | |
605 | * | |
606 | * This puts a job in the kernel-global workqueue. | |
607 | */ | |
7ad5b3a5 | 608 | int schedule_work(struct work_struct *work) |
1da177e4 LT |
609 | { |
610 | return queue_work(keventd_wq, work); | |
611 | } | |
ae90dd5d | 612 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 613 | |
c1a220e7 ZR |
614 | /* |
615 | * schedule_work_on - put work task on a specific cpu | |
616 | * @cpu: cpu to put the work task on | |
617 | * @work: job to be done | |
618 | * | |
619 | * This puts a job on a specific cpu | |
620 | */ | |
621 | int schedule_work_on(int cpu, struct work_struct *work) | |
622 | { | |
623 | return queue_work_on(cpu, keventd_wq, work); | |
624 | } | |
625 | EXPORT_SYMBOL(schedule_work_on); | |
626 | ||
0fcb78c2 REB |
627 | /** |
628 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
629 | * @dwork: job to be done |
630 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
631 | * |
632 | * After waiting for a given time this puts a job in the kernel-global | |
633 | * workqueue. | |
634 | */ | |
7ad5b3a5 | 635 | int schedule_delayed_work(struct delayed_work *dwork, |
82f67cd9 | 636 | unsigned long delay) |
1da177e4 | 637 | { |
52bad64d | 638 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 639 | } |
ae90dd5d | 640 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 641 | |
0fcb78c2 REB |
642 | /** |
643 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
644 | * @cpu: cpu to use | |
52bad64d | 645 | * @dwork: job to be done |
0fcb78c2 REB |
646 | * @delay: number of jiffies to wait |
647 | * | |
648 | * After waiting for a given time this puts a job in the kernel-global | |
649 | * workqueue on the specified CPU. | |
650 | */ | |
1da177e4 | 651 | int schedule_delayed_work_on(int cpu, |
52bad64d | 652 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 653 | { |
52bad64d | 654 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 655 | } |
ae90dd5d | 656 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 657 | |
b6136773 AM |
658 | /** |
659 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
660 | * @func: the function to call | |
b6136773 AM |
661 | * |
662 | * Returns zero on success. | |
663 | * Returns -ve errno on failure. | |
664 | * | |
b6136773 AM |
665 | * schedule_on_each_cpu() is very slow. |
666 | */ | |
65f27f38 | 667 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
668 | { |
669 | int cpu; | |
b6136773 | 670 | struct work_struct *works; |
15316ba8 | 671 | |
b6136773 AM |
672 | works = alloc_percpu(struct work_struct); |
673 | if (!works) | |
15316ba8 | 674 | return -ENOMEM; |
b6136773 | 675 | |
95402b38 | 676 | get_online_cpus(); |
15316ba8 | 677 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
678 | struct work_struct *work = per_cpu_ptr(works, cpu); |
679 | ||
680 | INIT_WORK(work, func); | |
8de6d308 | 681 | schedule_work_on(cpu, work); |
15316ba8 | 682 | } |
8616a89a ON |
683 | for_each_online_cpu(cpu) |
684 | flush_work(per_cpu_ptr(works, cpu)); | |
95402b38 | 685 | put_online_cpus(); |
b6136773 | 686 | free_percpu(works); |
15316ba8 CL |
687 | return 0; |
688 | } | |
689 | ||
1da177e4 LT |
690 | void flush_scheduled_work(void) |
691 | { | |
692 | flush_workqueue(keventd_wq); | |
693 | } | |
ae90dd5d | 694 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 695 | |
1fa44eca JB |
696 | /** |
697 | * execute_in_process_context - reliably execute the routine with user context | |
698 | * @fn: the function to execute | |
1fa44eca JB |
699 | * @ew: guaranteed storage for the execute work structure (must |
700 | * be available when the work executes) | |
701 | * | |
702 | * Executes the function immediately if process context is available, | |
703 | * otherwise schedules the function for delayed execution. | |
704 | * | |
705 | * Returns: 0 - function was executed | |
706 | * 1 - function was scheduled for execution | |
707 | */ | |
65f27f38 | 708 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
709 | { |
710 | if (!in_interrupt()) { | |
65f27f38 | 711 | fn(&ew->work); |
1fa44eca JB |
712 | return 0; |
713 | } | |
714 | ||
65f27f38 | 715 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
716 | schedule_work(&ew->work); |
717 | ||
718 | return 1; | |
719 | } | |
720 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
721 | ||
1da177e4 LT |
722 | int keventd_up(void) |
723 | { | |
724 | return keventd_wq != NULL; | |
725 | } | |
726 | ||
727 | int current_is_keventd(void) | |
728 | { | |
729 | struct cpu_workqueue_struct *cwq; | |
d243769d | 730 | int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ |
1da177e4 LT |
731 | int ret = 0; |
732 | ||
733 | BUG_ON(!keventd_wq); | |
734 | ||
89ada679 | 735 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
736 | if (current == cwq->thread) |
737 | ret = 1; | |
738 | ||
739 | return ret; | |
740 | ||
741 | } | |
742 | ||
3af24433 ON |
743 | static struct cpu_workqueue_struct * |
744 | init_cpu_workqueue(struct workqueue_struct *wq, int cpu) | |
1da177e4 | 745 | { |
89ada679 | 746 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 | 747 | |
3af24433 ON |
748 | cwq->wq = wq; |
749 | spin_lock_init(&cwq->lock); | |
750 | INIT_LIST_HEAD(&cwq->worklist); | |
751 | init_waitqueue_head(&cwq->more_work); | |
752 | ||
753 | return cwq; | |
1da177e4 LT |
754 | } |
755 | ||
e1d8aa9f FW |
756 | DEFINE_TRACE(workqueue_creation); |
757 | ||
3af24433 ON |
758 | static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
759 | { | |
0d557dc9 | 760 | struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; |
3af24433 | 761 | struct workqueue_struct *wq = cwq->wq; |
6cc88bc4 | 762 | const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d"; |
3af24433 ON |
763 | struct task_struct *p; |
764 | ||
765 | p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu); | |
766 | /* | |
767 | * Nobody can add the work_struct to this cwq, | |
768 | * if (caller is __create_workqueue) | |
769 | * nobody should see this wq | |
770 | * else // caller is CPU_UP_PREPARE | |
771 | * cpu is not on cpu_online_map | |
772 | * so we can abort safely. | |
773 | */ | |
774 | if (IS_ERR(p)) | |
775 | return PTR_ERR(p); | |
0d557dc9 HC |
776 | if (cwq->wq->rt) |
777 | sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m); | |
3af24433 | 778 | cwq->thread = p; |
3af24433 | 779 | |
e1d8aa9f FW |
780 | trace_workqueue_creation(cwq->thread, cpu); |
781 | ||
3af24433 ON |
782 | return 0; |
783 | } | |
784 | ||
06ba38a9 ON |
785 | static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
786 | { | |
787 | struct task_struct *p = cwq->thread; | |
788 | ||
789 | if (p != NULL) { | |
790 | if (cpu >= 0) | |
791 | kthread_bind(p, cpu); | |
792 | wake_up_process(p); | |
793 | } | |
794 | } | |
795 | ||
4e6045f1 JB |
796 | struct workqueue_struct *__create_workqueue_key(const char *name, |
797 | int singlethread, | |
798 | int freezeable, | |
0d557dc9 | 799 | int rt, |
eb13ba87 JB |
800 | struct lock_class_key *key, |
801 | const char *lock_name) | |
1da177e4 | 802 | { |
1da177e4 | 803 | struct workqueue_struct *wq; |
3af24433 ON |
804 | struct cpu_workqueue_struct *cwq; |
805 | int err = 0, cpu; | |
1da177e4 | 806 | |
3af24433 ON |
807 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
808 | if (!wq) | |
809 | return NULL; | |
810 | ||
811 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); | |
812 | if (!wq->cpu_wq) { | |
813 | kfree(wq); | |
814 | return NULL; | |
815 | } | |
816 | ||
817 | wq->name = name; | |
eb13ba87 | 818 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 819 | wq->singlethread = singlethread; |
3af24433 | 820 | wq->freezeable = freezeable; |
0d557dc9 | 821 | wq->rt = rt; |
cce1a165 | 822 | INIT_LIST_HEAD(&wq->list); |
3af24433 ON |
823 | |
824 | if (singlethread) { | |
3af24433 ON |
825 | cwq = init_cpu_workqueue(wq, singlethread_cpu); |
826 | err = create_workqueue_thread(cwq, singlethread_cpu); | |
06ba38a9 | 827 | start_workqueue_thread(cwq, -1); |
3af24433 | 828 | } else { |
3da1c84c | 829 | cpu_maps_update_begin(); |
6af8bf3d ON |
830 | /* |
831 | * We must place this wq on list even if the code below fails. | |
832 | * cpu_down(cpu) can remove cpu from cpu_populated_map before | |
833 | * destroy_workqueue() takes the lock, in that case we leak | |
834 | * cwq[cpu]->thread. | |
835 | */ | |
95402b38 | 836 | spin_lock(&workqueue_lock); |
3af24433 | 837 | list_add(&wq->list, &workqueues); |
95402b38 | 838 | spin_unlock(&workqueue_lock); |
6af8bf3d ON |
839 | /* |
840 | * We must initialize cwqs for each possible cpu even if we | |
841 | * are going to call destroy_workqueue() finally. Otherwise | |
842 | * cpu_up() can hit the uninitialized cwq once we drop the | |
843 | * lock. | |
844 | */ | |
3af24433 ON |
845 | for_each_possible_cpu(cpu) { |
846 | cwq = init_cpu_workqueue(wq, cpu); | |
847 | if (err || !cpu_online(cpu)) | |
848 | continue; | |
849 | err = create_workqueue_thread(cwq, cpu); | |
06ba38a9 | 850 | start_workqueue_thread(cwq, cpu); |
1da177e4 | 851 | } |
3da1c84c | 852 | cpu_maps_update_done(); |
3af24433 ON |
853 | } |
854 | ||
855 | if (err) { | |
856 | destroy_workqueue(wq); | |
857 | wq = NULL; | |
858 | } | |
859 | return wq; | |
860 | } | |
4e6045f1 | 861 | EXPORT_SYMBOL_GPL(__create_workqueue_key); |
1da177e4 | 862 | |
e1d8aa9f FW |
863 | DEFINE_TRACE(workqueue_destruction); |
864 | ||
1e35eaa2 | 865 | static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) |
3af24433 | 866 | { |
14441960 | 867 | /* |
3da1c84c ON |
868 | * Our caller is either destroy_workqueue() or CPU_POST_DEAD, |
869 | * cpu_add_remove_lock protects cwq->thread. | |
14441960 ON |
870 | */ |
871 | if (cwq->thread == NULL) | |
872 | return; | |
3af24433 | 873 | |
3295f0ef IM |
874 | lock_map_acquire(&cwq->wq->lockdep_map); |
875 | lock_map_release(&cwq->wq->lockdep_map); | |
4e6045f1 | 876 | |
13c22168 | 877 | flush_cpu_workqueue(cwq); |
14441960 | 878 | /* |
3da1c84c | 879 | * If the caller is CPU_POST_DEAD and cwq->worklist was not empty, |
13c22168 ON |
880 | * a concurrent flush_workqueue() can insert a barrier after us. |
881 | * However, in that case run_workqueue() won't return and check | |
882 | * kthread_should_stop() until it flushes all work_struct's. | |
14441960 ON |
883 | * When ->worklist becomes empty it is safe to exit because no |
884 | * more work_structs can be queued on this cwq: flush_workqueue | |
885 | * checks list_empty(), and a "normal" queue_work() can't use | |
886 | * a dead CPU. | |
887 | */ | |
e1d8aa9f | 888 | trace_workqueue_destruction(cwq->thread); |
14441960 ON |
889 | kthread_stop(cwq->thread); |
890 | cwq->thread = NULL; | |
3af24433 ON |
891 | } |
892 | ||
893 | /** | |
894 | * destroy_workqueue - safely terminate a workqueue | |
895 | * @wq: target workqueue | |
896 | * | |
897 | * Safely destroy a workqueue. All work currently pending will be done first. | |
898 | */ | |
899 | void destroy_workqueue(struct workqueue_struct *wq) | |
900 | { | |
e7577c50 | 901 | const struct cpumask *cpu_map = wq_cpu_map(wq); |
b1f4ec17 | 902 | int cpu; |
3af24433 | 903 | |
3da1c84c | 904 | cpu_maps_update_begin(); |
95402b38 | 905 | spin_lock(&workqueue_lock); |
b1f4ec17 | 906 | list_del(&wq->list); |
95402b38 | 907 | spin_unlock(&workqueue_lock); |
3af24433 | 908 | |
aa85ea5b | 909 | for_each_cpu(cpu, cpu_map) |
1e35eaa2 | 910 | cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu)); |
3da1c84c | 911 | cpu_maps_update_done(); |
9b41ea72 | 912 | |
3af24433 ON |
913 | free_percpu(wq->cpu_wq); |
914 | kfree(wq); | |
915 | } | |
916 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
917 | ||
918 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
919 | unsigned long action, | |
920 | void *hcpu) | |
921 | { | |
922 | unsigned int cpu = (unsigned long)hcpu; | |
923 | struct cpu_workqueue_struct *cwq; | |
924 | struct workqueue_struct *wq; | |
8448502c | 925 | int ret = NOTIFY_OK; |
3af24433 | 926 | |
8bb78442 RW |
927 | action &= ~CPU_TASKS_FROZEN; |
928 | ||
3af24433 | 929 | switch (action) { |
3af24433 | 930 | case CPU_UP_PREPARE: |
e7577c50 | 931 | cpumask_set_cpu(cpu, cpu_populated_map); |
3af24433 | 932 | } |
8448502c | 933 | undo: |
3af24433 ON |
934 | list_for_each_entry(wq, &workqueues, list) { |
935 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
936 | ||
937 | switch (action) { | |
938 | case CPU_UP_PREPARE: | |
939 | if (!create_workqueue_thread(cwq, cpu)) | |
940 | break; | |
95402b38 GS |
941 | printk(KERN_ERR "workqueue [%s] for %i failed\n", |
942 | wq->name, cpu); | |
8448502c ON |
943 | action = CPU_UP_CANCELED; |
944 | ret = NOTIFY_BAD; | |
945 | goto undo; | |
3af24433 ON |
946 | |
947 | case CPU_ONLINE: | |
06ba38a9 | 948 | start_workqueue_thread(cwq, cpu); |
3af24433 ON |
949 | break; |
950 | ||
951 | case CPU_UP_CANCELED: | |
06ba38a9 | 952 | start_workqueue_thread(cwq, -1); |
3da1c84c | 953 | case CPU_POST_DEAD: |
1e35eaa2 | 954 | cleanup_workqueue_thread(cwq); |
3af24433 ON |
955 | break; |
956 | } | |
1da177e4 LT |
957 | } |
958 | ||
00dfcaf7 ON |
959 | switch (action) { |
960 | case CPU_UP_CANCELED: | |
3da1c84c | 961 | case CPU_POST_DEAD: |
e7577c50 | 962 | cpumask_clear_cpu(cpu, cpu_populated_map); |
00dfcaf7 ON |
963 | } |
964 | ||
8448502c | 965 | return ret; |
1da177e4 | 966 | } |
1da177e4 | 967 | |
2d3854a3 | 968 | #ifdef CONFIG_SMP |
8ccad40d | 969 | |
2d3854a3 | 970 | struct work_for_cpu { |
6b44003e | 971 | struct completion completion; |
2d3854a3 RR |
972 | long (*fn)(void *); |
973 | void *arg; | |
974 | long ret; | |
975 | }; | |
976 | ||
6b44003e | 977 | static int do_work_for_cpu(void *_wfc) |
2d3854a3 | 978 | { |
6b44003e | 979 | struct work_for_cpu *wfc = _wfc; |
2d3854a3 | 980 | wfc->ret = wfc->fn(wfc->arg); |
6b44003e AM |
981 | complete(&wfc->completion); |
982 | return 0; | |
2d3854a3 RR |
983 | } |
984 | ||
985 | /** | |
986 | * work_on_cpu - run a function in user context on a particular cpu | |
987 | * @cpu: the cpu to run on | |
988 | * @fn: the function to run | |
989 | * @arg: the function arg | |
990 | * | |
31ad9081 RR |
991 | * This will return the value @fn returns. |
992 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
6b44003e | 993 | * The caller must not hold any locks which would prevent @fn from completing. |
2d3854a3 RR |
994 | */ |
995 | long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) | |
996 | { | |
6b44003e AM |
997 | struct task_struct *sub_thread; |
998 | struct work_for_cpu wfc = { | |
999 | .completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion), | |
1000 | .fn = fn, | |
1001 | .arg = arg, | |
1002 | }; | |
1003 | ||
1004 | sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu"); | |
1005 | if (IS_ERR(sub_thread)) | |
1006 | return PTR_ERR(sub_thread); | |
1007 | kthread_bind(sub_thread, cpu); | |
1008 | wake_up_process(sub_thread); | |
1009 | wait_for_completion(&wfc.completion); | |
2d3854a3 RR |
1010 | return wfc.ret; |
1011 | } | |
1012 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
1013 | #endif /* CONFIG_SMP */ | |
1014 | ||
c12920d1 | 1015 | void __init init_workqueues(void) |
1da177e4 | 1016 | { |
e7577c50 RR |
1017 | alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL); |
1018 | ||
1019 | cpumask_copy(cpu_populated_map, cpu_online_mask); | |
1020 | singlethread_cpu = cpumask_first(cpu_possible_mask); | |
1021 | cpu_singlethread_map = cpumask_of(singlethread_cpu); | |
1da177e4 LT |
1022 | hotcpu_notifier(workqueue_cpu_callback, 0); |
1023 | keventd_wq = create_workqueue("events"); | |
1024 | BUG_ON(!keventd_wq); | |
1025 | } |