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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> | |
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> |
1da177e4 LT |
36 | |
37 | /* | |
f756d5e2 NL |
38 | * The per-CPU workqueue (if single thread, we always use the first |
39 | * possible cpu). | |
1da177e4 LT |
40 | */ |
41 | struct cpu_workqueue_struct { | |
42 | ||
43 | spinlock_t lock; | |
44 | ||
1da177e4 LT |
45 | struct list_head worklist; |
46 | wait_queue_head_t more_work; | |
3af24433 | 47 | struct work_struct *current_work; |
1da177e4 LT |
48 | |
49 | struct workqueue_struct *wq; | |
36c8b586 | 50 | struct task_struct *thread; |
1da177e4 LT |
51 | |
52 | int run_depth; /* Detect run_workqueue() recursion depth */ | |
53 | } ____cacheline_aligned; | |
54 | ||
55 | /* | |
56 | * The externally visible workqueue abstraction is an array of | |
57 | * per-CPU workqueues: | |
58 | */ | |
59 | struct workqueue_struct { | |
89ada679 | 60 | struct cpu_workqueue_struct *cpu_wq; |
cce1a165 | 61 | struct list_head list; |
1da177e4 | 62 | const char *name; |
cce1a165 | 63 | int singlethread; |
319c2a98 | 64 | int freezeable; /* Freeze threads during suspend */ |
0d557dc9 | 65 | int rt; |
4e6045f1 JB |
66 | #ifdef CONFIG_LOCKDEP |
67 | struct lockdep_map lockdep_map; | |
68 | #endif | |
1da177e4 LT |
69 | }; |
70 | ||
95402b38 GS |
71 | /* Serializes the accesses to the list of workqueues. */ |
72 | static DEFINE_SPINLOCK(workqueue_lock); | |
1da177e4 LT |
73 | static LIST_HEAD(workqueues); |
74 | ||
3af24433 | 75 | static int singlethread_cpu __read_mostly; |
e7577c50 | 76 | static const struct cpumask *cpu_singlethread_map __read_mostly; |
14441960 ON |
77 | /* |
78 | * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD | |
79 | * flushes cwq->worklist. This means that flush_workqueue/wait_on_work | |
80 | * which comes in between can't use for_each_online_cpu(). We could | |
81 | * use cpu_possible_map, the cpumask below is more a documentation | |
82 | * than optimization. | |
83 | */ | |
e7577c50 | 84 | static cpumask_var_t cpu_populated_map __read_mostly; |
f756d5e2 | 85 | |
1da177e4 | 86 | /* If it's single threaded, it isn't in the list of workqueues. */ |
6cc88bc4 | 87 | static inline int is_wq_single_threaded(struct workqueue_struct *wq) |
1da177e4 | 88 | { |
cce1a165 | 89 | return wq->singlethread; |
1da177e4 LT |
90 | } |
91 | ||
e7577c50 | 92 | static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq) |
b1f4ec17 | 93 | { |
6cc88bc4 | 94 | return is_wq_single_threaded(wq) |
e7577c50 | 95 | ? cpu_singlethread_map : cpu_populated_map; |
b1f4ec17 ON |
96 | } |
97 | ||
a848e3b6 ON |
98 | static |
99 | struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu) | |
100 | { | |
6cc88bc4 | 101 | if (unlikely(is_wq_single_threaded(wq))) |
a848e3b6 ON |
102 | cpu = singlethread_cpu; |
103 | return per_cpu_ptr(wq->cpu_wq, cpu); | |
104 | } | |
105 | ||
4594bf15 DH |
106 | /* |
107 | * Set the workqueue on which a work item is to be run | |
108 | * - Must *only* be called if the pending flag is set | |
109 | */ | |
ed7c0fee ON |
110 | static inline void set_wq_data(struct work_struct *work, |
111 | struct cpu_workqueue_struct *cwq) | |
365970a1 | 112 | { |
4594bf15 DH |
113 | unsigned long new; |
114 | ||
115 | BUG_ON(!work_pending(work)); | |
365970a1 | 116 | |
ed7c0fee | 117 | new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING); |
a08727ba LT |
118 | new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); |
119 | atomic_long_set(&work->data, new); | |
365970a1 DH |
120 | } |
121 | ||
ed7c0fee ON |
122 | static inline |
123 | struct cpu_workqueue_struct *get_wq_data(struct work_struct *work) | |
365970a1 | 124 | { |
a08727ba | 125 | return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); |
365970a1 DH |
126 | } |
127 | ||
b89deed3 | 128 | static void insert_work(struct cpu_workqueue_struct *cwq, |
1a4d9b0a | 129 | struct work_struct *work, struct list_head *head) |
b89deed3 ON |
130 | { |
131 | set_wq_data(work, cwq); | |
6e84d644 ON |
132 | /* |
133 | * Ensure that we get the right work->data if we see the | |
134 | * result of list_add() below, see try_to_grab_pending(). | |
135 | */ | |
136 | smp_wmb(); | |
1a4d9b0a | 137 | list_add_tail(&work->entry, head); |
b89deed3 ON |
138 | wake_up(&cwq->more_work); |
139 | } | |
140 | ||
1da177e4 LT |
141 | static void __queue_work(struct cpu_workqueue_struct *cwq, |
142 | struct work_struct *work) | |
143 | { | |
144 | unsigned long flags; | |
145 | ||
146 | spin_lock_irqsave(&cwq->lock, flags); | |
1a4d9b0a | 147 | insert_work(cwq, work, &cwq->worklist); |
1da177e4 LT |
148 | spin_unlock_irqrestore(&cwq->lock, flags); |
149 | } | |
150 | ||
0fcb78c2 REB |
151 | /** |
152 | * queue_work - queue work on a workqueue | |
153 | * @wq: workqueue to use | |
154 | * @work: work to queue | |
155 | * | |
057647fc | 156 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 | 157 | * |
00dfcaf7 ON |
158 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
159 | * it can be processed by another CPU. | |
1da177e4 | 160 | */ |
7ad5b3a5 | 161 | int queue_work(struct workqueue_struct *wq, struct work_struct *work) |
1da177e4 | 162 | { |
ef1ca236 ON |
163 | int ret; |
164 | ||
165 | ret = queue_work_on(get_cpu(), wq, work); | |
166 | put_cpu(); | |
167 | ||
1da177e4 LT |
168 | return ret; |
169 | } | |
ae90dd5d | 170 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 171 | |
c1a220e7 ZR |
172 | /** |
173 | * queue_work_on - queue work on specific cpu | |
174 | * @cpu: CPU number to execute work on | |
175 | * @wq: workqueue to use | |
176 | * @work: work to queue | |
177 | * | |
178 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
179 | * | |
180 | * We queue the work to a specific CPU, the caller must ensure it | |
181 | * can't go away. | |
182 | */ | |
183 | int | |
184 | queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) | |
185 | { | |
186 | int ret = 0; | |
187 | ||
188 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | |
189 | BUG_ON(!list_empty(&work->entry)); | |
190 | __queue_work(wq_per_cpu(wq, cpu), work); | |
191 | ret = 1; | |
192 | } | |
193 | return ret; | |
194 | } | |
195 | EXPORT_SYMBOL_GPL(queue_work_on); | |
196 | ||
6d141c3f | 197 | static void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 198 | { |
52bad64d | 199 | struct delayed_work *dwork = (struct delayed_work *)__data; |
ed7c0fee ON |
200 | struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
201 | struct workqueue_struct *wq = cwq->wq; | |
1da177e4 | 202 | |
a848e3b6 | 203 | __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work); |
1da177e4 LT |
204 | } |
205 | ||
0fcb78c2 REB |
206 | /** |
207 | * queue_delayed_work - queue work on a workqueue after delay | |
208 | * @wq: workqueue to use | |
af9997e4 | 209 | * @dwork: delayable work to queue |
0fcb78c2 REB |
210 | * @delay: number of jiffies to wait before queueing |
211 | * | |
057647fc | 212 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 213 | */ |
7ad5b3a5 | 214 | int queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 215 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 216 | { |
52bad64d | 217 | if (delay == 0) |
63bc0362 | 218 | return queue_work(wq, &dwork->work); |
1da177e4 | 219 | |
63bc0362 | 220 | return queue_delayed_work_on(-1, wq, dwork, delay); |
1da177e4 | 221 | } |
ae90dd5d | 222 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 223 | |
0fcb78c2 REB |
224 | /** |
225 | * queue_delayed_work_on - queue work on specific CPU after delay | |
226 | * @cpu: CPU number to execute work on | |
227 | * @wq: workqueue to use | |
af9997e4 | 228 | * @dwork: work to queue |
0fcb78c2 REB |
229 | * @delay: number of jiffies to wait before queueing |
230 | * | |
057647fc | 231 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 232 | */ |
7a6bc1cd | 233 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 234 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
235 | { |
236 | int ret = 0; | |
52bad64d DH |
237 | struct timer_list *timer = &dwork->timer; |
238 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 239 | |
a08727ba | 240 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
7a6bc1cd VP |
241 | BUG_ON(timer_pending(timer)); |
242 | BUG_ON(!list_empty(&work->entry)); | |
243 | ||
8a3e77cc AL |
244 | timer_stats_timer_set_start_info(&dwork->timer); |
245 | ||
ed7c0fee | 246 | /* This stores cwq for the moment, for the timer_fn */ |
a848e3b6 | 247 | set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id())); |
7a6bc1cd | 248 | timer->expires = jiffies + delay; |
52bad64d | 249 | timer->data = (unsigned long)dwork; |
7a6bc1cd | 250 | timer->function = delayed_work_timer_fn; |
63bc0362 ON |
251 | |
252 | if (unlikely(cpu >= 0)) | |
253 | add_timer_on(timer, cpu); | |
254 | else | |
255 | add_timer(timer); | |
7a6bc1cd VP |
256 | ret = 1; |
257 | } | |
258 | return ret; | |
259 | } | |
ae90dd5d | 260 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 261 | |
858119e1 | 262 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 263 | { |
f293ea92 | 264 | spin_lock_irq(&cwq->lock); |
1da177e4 LT |
265 | cwq->run_depth++; |
266 | if (cwq->run_depth > 3) { | |
267 | /* morton gets to eat his hat */ | |
268 | printk("%s: recursion depth exceeded: %d\n", | |
af1f16d0 | 269 | __func__, cwq->run_depth); |
1da177e4 LT |
270 | dump_stack(); |
271 | } | |
272 | while (!list_empty(&cwq->worklist)) { | |
273 | struct work_struct *work = list_entry(cwq->worklist.next, | |
274 | struct work_struct, entry); | |
6bb49e59 | 275 | work_func_t f = work->func; |
4e6045f1 JB |
276 | #ifdef CONFIG_LOCKDEP |
277 | /* | |
278 | * It is permissible to free the struct work_struct | |
279 | * from inside the function that is called from it, | |
280 | * this we need to take into account for lockdep too. | |
281 | * To avoid bogus "held lock freed" warnings as well | |
282 | * as problems when looking into work->lockdep_map, | |
283 | * make a copy and use that here. | |
284 | */ | |
285 | struct lockdep_map lockdep_map = work->lockdep_map; | |
286 | #endif | |
1da177e4 | 287 | |
b89deed3 | 288 | cwq->current_work = work; |
1da177e4 | 289 | list_del_init(cwq->worklist.next); |
f293ea92 | 290 | spin_unlock_irq(&cwq->lock); |
1da177e4 | 291 | |
365970a1 | 292 | BUG_ON(get_wq_data(work) != cwq); |
23b2e599 | 293 | work_clear_pending(work); |
3295f0ef IM |
294 | lock_map_acquire(&cwq->wq->lockdep_map); |
295 | lock_map_acquire(&lockdep_map); | |
65f27f38 | 296 | f(work); |
3295f0ef IM |
297 | lock_map_release(&lockdep_map); |
298 | lock_map_release(&cwq->wq->lockdep_map); | |
1da177e4 | 299 | |
d5abe669 PZ |
300 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
301 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
302 | "%s/0x%08x/%d\n", | |
303 | current->comm, preempt_count(), | |
ba25f9dc | 304 | task_pid_nr(current)); |
d5abe669 PZ |
305 | printk(KERN_ERR " last function: "); |
306 | print_symbol("%s\n", (unsigned long)f); | |
307 | debug_show_held_locks(current); | |
308 | dump_stack(); | |
309 | } | |
310 | ||
f293ea92 | 311 | spin_lock_irq(&cwq->lock); |
b89deed3 | 312 | cwq->current_work = NULL; |
1da177e4 LT |
313 | } |
314 | cwq->run_depth--; | |
f293ea92 | 315 | spin_unlock_irq(&cwq->lock); |
1da177e4 LT |
316 | } |
317 | ||
318 | static int worker_thread(void *__cwq) | |
319 | { | |
320 | struct cpu_workqueue_struct *cwq = __cwq; | |
3af24433 | 321 | DEFINE_WAIT(wait); |
1da177e4 | 322 | |
83144186 RW |
323 | if (cwq->wq->freezeable) |
324 | set_freezable(); | |
1da177e4 LT |
325 | |
326 | set_user_nice(current, -5); | |
1da177e4 | 327 | |
3af24433 | 328 | for (;;) { |
3af24433 | 329 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
14441960 ON |
330 | if (!freezing(current) && |
331 | !kthread_should_stop() && | |
332 | list_empty(&cwq->worklist)) | |
1da177e4 | 333 | schedule(); |
3af24433 ON |
334 | finish_wait(&cwq->more_work, &wait); |
335 | ||
85f4186a ON |
336 | try_to_freeze(); |
337 | ||
14441960 | 338 | if (kthread_should_stop()) |
3af24433 | 339 | break; |
1da177e4 | 340 | |
3af24433 | 341 | run_workqueue(cwq); |
1da177e4 | 342 | } |
3af24433 | 343 | |
1da177e4 LT |
344 | return 0; |
345 | } | |
346 | ||
fc2e4d70 ON |
347 | struct wq_barrier { |
348 | struct work_struct work; | |
349 | struct completion done; | |
350 | }; | |
351 | ||
352 | static void wq_barrier_func(struct work_struct *work) | |
353 | { | |
354 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
355 | complete(&barr->done); | |
356 | } | |
357 | ||
83c22520 | 358 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
1a4d9b0a | 359 | struct wq_barrier *barr, struct list_head *head) |
fc2e4d70 ON |
360 | { |
361 | INIT_WORK(&barr->work, wq_barrier_func); | |
362 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); | |
363 | ||
364 | init_completion(&barr->done); | |
83c22520 | 365 | |
1a4d9b0a | 366 | insert_work(cwq, &barr->work, head); |
fc2e4d70 ON |
367 | } |
368 | ||
14441960 | 369 | static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 370 | { |
14441960 ON |
371 | int active; |
372 | ||
1da177e4 LT |
373 | if (cwq->thread == current) { |
374 | /* | |
375 | * Probably keventd trying to flush its own queue. So simply run | |
376 | * it by hand rather than deadlocking. | |
377 | */ | |
378 | run_workqueue(cwq); | |
14441960 | 379 | active = 1; |
1da177e4 | 380 | } else { |
fc2e4d70 | 381 | struct wq_barrier barr; |
1da177e4 | 382 | |
14441960 | 383 | active = 0; |
83c22520 ON |
384 | spin_lock_irq(&cwq->lock); |
385 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
1a4d9b0a | 386 | insert_wq_barrier(cwq, &barr, &cwq->worklist); |
83c22520 ON |
387 | active = 1; |
388 | } | |
389 | spin_unlock_irq(&cwq->lock); | |
1da177e4 | 390 | |
d721304d | 391 | if (active) |
83c22520 | 392 | wait_for_completion(&barr.done); |
1da177e4 | 393 | } |
14441960 ON |
394 | |
395 | return active; | |
1da177e4 LT |
396 | } |
397 | ||
0fcb78c2 | 398 | /** |
1da177e4 | 399 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 400 | * @wq: workqueue to flush |
1da177e4 LT |
401 | * |
402 | * Forces execution of the workqueue and blocks until its completion. | |
403 | * This is typically used in driver shutdown handlers. | |
404 | * | |
fc2e4d70 ON |
405 | * We sleep until all works which were queued on entry have been handled, |
406 | * but we are not livelocked by new incoming ones. | |
1da177e4 LT |
407 | * |
408 | * This function used to run the workqueues itself. Now we just wait for the | |
409 | * helper threads to do it. | |
410 | */ | |
7ad5b3a5 | 411 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 412 | { |
e7577c50 | 413 | const struct cpumask *cpu_map = wq_cpu_map(wq); |
cce1a165 | 414 | int cpu; |
1da177e4 | 415 | |
b1f4ec17 | 416 | might_sleep(); |
3295f0ef IM |
417 | lock_map_acquire(&wq->lockdep_map); |
418 | lock_map_release(&wq->lockdep_map); | |
363ab6f1 | 419 | for_each_cpu_mask_nr(cpu, *cpu_map) |
b1f4ec17 | 420 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
1da177e4 | 421 | } |
ae90dd5d | 422 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 423 | |
db700897 ON |
424 | /** |
425 | * flush_work - block until a work_struct's callback has terminated | |
426 | * @work: the work which is to be flushed | |
427 | * | |
a67da70d ON |
428 | * Returns false if @work has already terminated. |
429 | * | |
db700897 ON |
430 | * It is expected that, prior to calling flush_work(), the caller has |
431 | * arranged for the work to not be requeued, otherwise it doesn't make | |
432 | * sense to use this function. | |
433 | */ | |
434 | int flush_work(struct work_struct *work) | |
435 | { | |
436 | struct cpu_workqueue_struct *cwq; | |
437 | struct list_head *prev; | |
438 | struct wq_barrier barr; | |
439 | ||
440 | might_sleep(); | |
441 | cwq = get_wq_data(work); | |
442 | if (!cwq) | |
443 | return 0; | |
444 | ||
3295f0ef IM |
445 | lock_map_acquire(&cwq->wq->lockdep_map); |
446 | lock_map_release(&cwq->wq->lockdep_map); | |
a67da70d | 447 | |
db700897 ON |
448 | prev = NULL; |
449 | spin_lock_irq(&cwq->lock); | |
450 | if (!list_empty(&work->entry)) { | |
451 | /* | |
452 | * See the comment near try_to_grab_pending()->smp_rmb(). | |
453 | * If it was re-queued under us we are not going to wait. | |
454 | */ | |
455 | smp_rmb(); | |
456 | if (unlikely(cwq != get_wq_data(work))) | |
457 | goto out; | |
458 | prev = &work->entry; | |
459 | } else { | |
460 | if (cwq->current_work != work) | |
461 | goto out; | |
462 | prev = &cwq->worklist; | |
463 | } | |
464 | insert_wq_barrier(cwq, &barr, prev->next); | |
465 | out: | |
466 | spin_unlock_irq(&cwq->lock); | |
467 | if (!prev) | |
468 | return 0; | |
469 | ||
470 | wait_for_completion(&barr.done); | |
471 | return 1; | |
472 | } | |
473 | EXPORT_SYMBOL_GPL(flush_work); | |
474 | ||
6e84d644 | 475 | /* |
1f1f642e | 476 | * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, |
6e84d644 ON |
477 | * so this work can't be re-armed in any way. |
478 | */ | |
479 | static int try_to_grab_pending(struct work_struct *work) | |
480 | { | |
481 | struct cpu_workqueue_struct *cwq; | |
1f1f642e | 482 | int ret = -1; |
6e84d644 ON |
483 | |
484 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) | |
1f1f642e | 485 | return 0; |
6e84d644 ON |
486 | |
487 | /* | |
488 | * The queueing is in progress, or it is already queued. Try to | |
489 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
490 | */ | |
491 | ||
492 | cwq = get_wq_data(work); | |
493 | if (!cwq) | |
494 | return ret; | |
495 | ||
496 | spin_lock_irq(&cwq->lock); | |
497 | if (!list_empty(&work->entry)) { | |
498 | /* | |
499 | * This work is queued, but perhaps we locked the wrong cwq. | |
500 | * In that case we must see the new value after rmb(), see | |
501 | * insert_work()->wmb(). | |
502 | */ | |
503 | smp_rmb(); | |
504 | if (cwq == get_wq_data(work)) { | |
505 | list_del_init(&work->entry); | |
506 | ret = 1; | |
507 | } | |
508 | } | |
509 | spin_unlock_irq(&cwq->lock); | |
510 | ||
511 | return ret; | |
512 | } | |
513 | ||
514 | static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | |
b89deed3 ON |
515 | struct work_struct *work) |
516 | { | |
517 | struct wq_barrier barr; | |
518 | int running = 0; | |
519 | ||
520 | spin_lock_irq(&cwq->lock); | |
521 | if (unlikely(cwq->current_work == work)) { | |
1a4d9b0a | 522 | insert_wq_barrier(cwq, &barr, cwq->worklist.next); |
b89deed3 ON |
523 | running = 1; |
524 | } | |
525 | spin_unlock_irq(&cwq->lock); | |
526 | ||
3af24433 | 527 | if (unlikely(running)) |
b89deed3 | 528 | wait_for_completion(&barr.done); |
b89deed3 ON |
529 | } |
530 | ||
6e84d644 | 531 | static void wait_on_work(struct work_struct *work) |
b89deed3 ON |
532 | { |
533 | struct cpu_workqueue_struct *cwq; | |
28e53bdd | 534 | struct workqueue_struct *wq; |
e7577c50 | 535 | const struct cpumask *cpu_map; |
b1f4ec17 | 536 | int cpu; |
b89deed3 | 537 | |
f293ea92 ON |
538 | might_sleep(); |
539 | ||
3295f0ef IM |
540 | lock_map_acquire(&work->lockdep_map); |
541 | lock_map_release(&work->lockdep_map); | |
4e6045f1 | 542 | |
b89deed3 | 543 | cwq = get_wq_data(work); |
b89deed3 | 544 | if (!cwq) |
3af24433 | 545 | return; |
b89deed3 | 546 | |
28e53bdd ON |
547 | wq = cwq->wq; |
548 | cpu_map = wq_cpu_map(wq); | |
549 | ||
363ab6f1 | 550 | for_each_cpu_mask_nr(cpu, *cpu_map) |
6e84d644 ON |
551 | wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
552 | } | |
553 | ||
1f1f642e ON |
554 | static int __cancel_work_timer(struct work_struct *work, |
555 | struct timer_list* timer) | |
556 | { | |
557 | int ret; | |
558 | ||
559 | do { | |
560 | ret = (timer && likely(del_timer(timer))); | |
561 | if (!ret) | |
562 | ret = try_to_grab_pending(work); | |
563 | wait_on_work(work); | |
564 | } while (unlikely(ret < 0)); | |
565 | ||
566 | work_clear_pending(work); | |
567 | return ret; | |
568 | } | |
569 | ||
6e84d644 ON |
570 | /** |
571 | * cancel_work_sync - block until a work_struct's callback has terminated | |
572 | * @work: the work which is to be flushed | |
573 | * | |
1f1f642e ON |
574 | * Returns true if @work was pending. |
575 | * | |
6e84d644 ON |
576 | * cancel_work_sync() will cancel the work if it is queued. If the work's |
577 | * callback appears to be running, cancel_work_sync() will block until it | |
578 | * has completed. | |
579 | * | |
580 | * It is possible to use this function if the work re-queues itself. It can | |
581 | * cancel the work even if it migrates to another workqueue, however in that | |
582 | * case it only guarantees that work->func() has completed on the last queued | |
583 | * workqueue. | |
584 | * | |
585 | * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not | |
586 | * pending, otherwise it goes into a busy-wait loop until the timer expires. | |
587 | * | |
588 | * The caller must ensure that workqueue_struct on which this work was last | |
589 | * queued can't be destroyed before this function returns. | |
590 | */ | |
1f1f642e | 591 | int cancel_work_sync(struct work_struct *work) |
6e84d644 | 592 | { |
1f1f642e | 593 | return __cancel_work_timer(work, NULL); |
b89deed3 | 594 | } |
28e53bdd | 595 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 596 | |
6e84d644 | 597 | /** |
f5a421a4 | 598 | * cancel_delayed_work_sync - reliably kill off a delayed work. |
6e84d644 ON |
599 | * @dwork: the delayed work struct |
600 | * | |
1f1f642e ON |
601 | * Returns true if @dwork was pending. |
602 | * | |
6e84d644 ON |
603 | * It is possible to use this function if @dwork rearms itself via queue_work() |
604 | * or queue_delayed_work(). See also the comment for cancel_work_sync(). | |
605 | */ | |
1f1f642e | 606 | int cancel_delayed_work_sync(struct delayed_work *dwork) |
6e84d644 | 607 | { |
1f1f642e | 608 | return __cancel_work_timer(&dwork->work, &dwork->timer); |
6e84d644 | 609 | } |
f5a421a4 | 610 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 611 | |
6e84d644 | 612 | static struct workqueue_struct *keventd_wq __read_mostly; |
1da177e4 | 613 | |
0fcb78c2 REB |
614 | /** |
615 | * schedule_work - put work task in global workqueue | |
616 | * @work: job to be done | |
617 | * | |
618 | * This puts a job in the kernel-global workqueue. | |
619 | */ | |
7ad5b3a5 | 620 | int schedule_work(struct work_struct *work) |
1da177e4 LT |
621 | { |
622 | return queue_work(keventd_wq, work); | |
623 | } | |
ae90dd5d | 624 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 625 | |
c1a220e7 ZR |
626 | /* |
627 | * schedule_work_on - put work task on a specific cpu | |
628 | * @cpu: cpu to put the work task on | |
629 | * @work: job to be done | |
630 | * | |
631 | * This puts a job on a specific cpu | |
632 | */ | |
633 | int schedule_work_on(int cpu, struct work_struct *work) | |
634 | { | |
635 | return queue_work_on(cpu, keventd_wq, work); | |
636 | } | |
637 | EXPORT_SYMBOL(schedule_work_on); | |
638 | ||
0fcb78c2 REB |
639 | /** |
640 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
641 | * @dwork: job to be done |
642 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
643 | * |
644 | * After waiting for a given time this puts a job in the kernel-global | |
645 | * workqueue. | |
646 | */ | |
7ad5b3a5 | 647 | int schedule_delayed_work(struct delayed_work *dwork, |
82f67cd9 | 648 | unsigned long delay) |
1da177e4 | 649 | { |
52bad64d | 650 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 651 | } |
ae90dd5d | 652 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 653 | |
0fcb78c2 REB |
654 | /** |
655 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
656 | * @cpu: cpu to use | |
52bad64d | 657 | * @dwork: job to be done |
0fcb78c2 REB |
658 | * @delay: number of jiffies to wait |
659 | * | |
660 | * After waiting for a given time this puts a job in the kernel-global | |
661 | * workqueue on the specified CPU. | |
662 | */ | |
1da177e4 | 663 | int schedule_delayed_work_on(int cpu, |
52bad64d | 664 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 665 | { |
52bad64d | 666 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 667 | } |
ae90dd5d | 668 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 669 | |
b6136773 AM |
670 | /** |
671 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
672 | * @func: the function to call | |
b6136773 AM |
673 | * |
674 | * Returns zero on success. | |
675 | * Returns -ve errno on failure. | |
676 | * | |
b6136773 AM |
677 | * schedule_on_each_cpu() is very slow. |
678 | */ | |
65f27f38 | 679 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
680 | { |
681 | int cpu; | |
b6136773 | 682 | struct work_struct *works; |
15316ba8 | 683 | |
b6136773 AM |
684 | works = alloc_percpu(struct work_struct); |
685 | if (!works) | |
15316ba8 | 686 | return -ENOMEM; |
b6136773 | 687 | |
95402b38 | 688 | get_online_cpus(); |
15316ba8 | 689 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
690 | struct work_struct *work = per_cpu_ptr(works, cpu); |
691 | ||
692 | INIT_WORK(work, func); | |
8de6d308 | 693 | schedule_work_on(cpu, work); |
15316ba8 | 694 | } |
8616a89a ON |
695 | for_each_online_cpu(cpu) |
696 | flush_work(per_cpu_ptr(works, cpu)); | |
95402b38 | 697 | put_online_cpus(); |
b6136773 | 698 | free_percpu(works); |
15316ba8 CL |
699 | return 0; |
700 | } | |
701 | ||
1da177e4 LT |
702 | void flush_scheduled_work(void) |
703 | { | |
704 | flush_workqueue(keventd_wq); | |
705 | } | |
ae90dd5d | 706 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 707 | |
1fa44eca JB |
708 | /** |
709 | * execute_in_process_context - reliably execute the routine with user context | |
710 | * @fn: the function to execute | |
1fa44eca JB |
711 | * @ew: guaranteed storage for the execute work structure (must |
712 | * be available when the work executes) | |
713 | * | |
714 | * Executes the function immediately if process context is available, | |
715 | * otherwise schedules the function for delayed execution. | |
716 | * | |
717 | * Returns: 0 - function was executed | |
718 | * 1 - function was scheduled for execution | |
719 | */ | |
65f27f38 | 720 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
721 | { |
722 | if (!in_interrupt()) { | |
65f27f38 | 723 | fn(&ew->work); |
1fa44eca JB |
724 | return 0; |
725 | } | |
726 | ||
65f27f38 | 727 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
728 | schedule_work(&ew->work); |
729 | ||
730 | return 1; | |
731 | } | |
732 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
733 | ||
1da177e4 LT |
734 | int keventd_up(void) |
735 | { | |
736 | return keventd_wq != NULL; | |
737 | } | |
738 | ||
739 | int current_is_keventd(void) | |
740 | { | |
741 | struct cpu_workqueue_struct *cwq; | |
d243769d | 742 | int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ |
1da177e4 LT |
743 | int ret = 0; |
744 | ||
745 | BUG_ON(!keventd_wq); | |
746 | ||
89ada679 | 747 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
748 | if (current == cwq->thread) |
749 | ret = 1; | |
750 | ||
751 | return ret; | |
752 | ||
753 | } | |
754 | ||
3af24433 ON |
755 | static struct cpu_workqueue_struct * |
756 | init_cpu_workqueue(struct workqueue_struct *wq, int cpu) | |
1da177e4 | 757 | { |
89ada679 | 758 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 | 759 | |
3af24433 ON |
760 | cwq->wq = wq; |
761 | spin_lock_init(&cwq->lock); | |
762 | INIT_LIST_HEAD(&cwq->worklist); | |
763 | init_waitqueue_head(&cwq->more_work); | |
764 | ||
765 | return cwq; | |
1da177e4 LT |
766 | } |
767 | ||
3af24433 ON |
768 | static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
769 | { | |
0d557dc9 | 770 | struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; |
3af24433 | 771 | struct workqueue_struct *wq = cwq->wq; |
6cc88bc4 | 772 | const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d"; |
3af24433 ON |
773 | struct task_struct *p; |
774 | ||
775 | p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu); | |
776 | /* | |
777 | * Nobody can add the work_struct to this cwq, | |
778 | * if (caller is __create_workqueue) | |
779 | * nobody should see this wq | |
780 | * else // caller is CPU_UP_PREPARE | |
781 | * cpu is not on cpu_online_map | |
782 | * so we can abort safely. | |
783 | */ | |
784 | if (IS_ERR(p)) | |
785 | return PTR_ERR(p); | |
0d557dc9 HC |
786 | if (cwq->wq->rt) |
787 | sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m); | |
3af24433 | 788 | cwq->thread = p; |
3af24433 ON |
789 | |
790 | return 0; | |
791 | } | |
792 | ||
06ba38a9 ON |
793 | static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
794 | { | |
795 | struct task_struct *p = cwq->thread; | |
796 | ||
797 | if (p != NULL) { | |
798 | if (cpu >= 0) | |
799 | kthread_bind(p, cpu); | |
800 | wake_up_process(p); | |
801 | } | |
802 | } | |
803 | ||
4e6045f1 JB |
804 | struct workqueue_struct *__create_workqueue_key(const char *name, |
805 | int singlethread, | |
806 | int freezeable, | |
0d557dc9 | 807 | int rt, |
eb13ba87 JB |
808 | struct lock_class_key *key, |
809 | const char *lock_name) | |
1da177e4 | 810 | { |
1da177e4 | 811 | struct workqueue_struct *wq; |
3af24433 ON |
812 | struct cpu_workqueue_struct *cwq; |
813 | int err = 0, cpu; | |
1da177e4 | 814 | |
3af24433 ON |
815 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
816 | if (!wq) | |
817 | return NULL; | |
818 | ||
819 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); | |
820 | if (!wq->cpu_wq) { | |
821 | kfree(wq); | |
822 | return NULL; | |
823 | } | |
824 | ||
825 | wq->name = name; | |
eb13ba87 | 826 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 827 | wq->singlethread = singlethread; |
3af24433 | 828 | wq->freezeable = freezeable; |
0d557dc9 | 829 | wq->rt = rt; |
cce1a165 | 830 | INIT_LIST_HEAD(&wq->list); |
3af24433 ON |
831 | |
832 | if (singlethread) { | |
3af24433 ON |
833 | cwq = init_cpu_workqueue(wq, singlethread_cpu); |
834 | err = create_workqueue_thread(cwq, singlethread_cpu); | |
06ba38a9 | 835 | start_workqueue_thread(cwq, -1); |
3af24433 | 836 | } else { |
3da1c84c | 837 | cpu_maps_update_begin(); |
6af8bf3d ON |
838 | /* |
839 | * We must place this wq on list even if the code below fails. | |
840 | * cpu_down(cpu) can remove cpu from cpu_populated_map before | |
841 | * destroy_workqueue() takes the lock, in that case we leak | |
842 | * cwq[cpu]->thread. | |
843 | */ | |
95402b38 | 844 | spin_lock(&workqueue_lock); |
3af24433 | 845 | list_add(&wq->list, &workqueues); |
95402b38 | 846 | spin_unlock(&workqueue_lock); |
6af8bf3d ON |
847 | /* |
848 | * We must initialize cwqs for each possible cpu even if we | |
849 | * are going to call destroy_workqueue() finally. Otherwise | |
850 | * cpu_up() can hit the uninitialized cwq once we drop the | |
851 | * lock. | |
852 | */ | |
3af24433 ON |
853 | for_each_possible_cpu(cpu) { |
854 | cwq = init_cpu_workqueue(wq, cpu); | |
855 | if (err || !cpu_online(cpu)) | |
856 | continue; | |
857 | err = create_workqueue_thread(cwq, cpu); | |
06ba38a9 | 858 | start_workqueue_thread(cwq, cpu); |
1da177e4 | 859 | } |
3da1c84c | 860 | cpu_maps_update_done(); |
3af24433 ON |
861 | } |
862 | ||
863 | if (err) { | |
864 | destroy_workqueue(wq); | |
865 | wq = NULL; | |
866 | } | |
867 | return wq; | |
868 | } | |
4e6045f1 | 869 | EXPORT_SYMBOL_GPL(__create_workqueue_key); |
1da177e4 | 870 | |
1e35eaa2 | 871 | static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) |
3af24433 | 872 | { |
14441960 | 873 | /* |
3da1c84c ON |
874 | * Our caller is either destroy_workqueue() or CPU_POST_DEAD, |
875 | * cpu_add_remove_lock protects cwq->thread. | |
14441960 ON |
876 | */ |
877 | if (cwq->thread == NULL) | |
878 | return; | |
3af24433 | 879 | |
3295f0ef IM |
880 | lock_map_acquire(&cwq->wq->lockdep_map); |
881 | lock_map_release(&cwq->wq->lockdep_map); | |
4e6045f1 | 882 | |
13c22168 | 883 | flush_cpu_workqueue(cwq); |
14441960 | 884 | /* |
3da1c84c | 885 | * If the caller is CPU_POST_DEAD and cwq->worklist was not empty, |
13c22168 ON |
886 | * a concurrent flush_workqueue() can insert a barrier after us. |
887 | * However, in that case run_workqueue() won't return and check | |
888 | * kthread_should_stop() until it flushes all work_struct's. | |
14441960 ON |
889 | * When ->worklist becomes empty it is safe to exit because no |
890 | * more work_structs can be queued on this cwq: flush_workqueue | |
891 | * checks list_empty(), and a "normal" queue_work() can't use | |
892 | * a dead CPU. | |
893 | */ | |
14441960 ON |
894 | kthread_stop(cwq->thread); |
895 | cwq->thread = NULL; | |
3af24433 ON |
896 | } |
897 | ||
898 | /** | |
899 | * destroy_workqueue - safely terminate a workqueue | |
900 | * @wq: target workqueue | |
901 | * | |
902 | * Safely destroy a workqueue. All work currently pending will be done first. | |
903 | */ | |
904 | void destroy_workqueue(struct workqueue_struct *wq) | |
905 | { | |
e7577c50 | 906 | const struct cpumask *cpu_map = wq_cpu_map(wq); |
b1f4ec17 | 907 | int cpu; |
3af24433 | 908 | |
3da1c84c | 909 | cpu_maps_update_begin(); |
95402b38 | 910 | spin_lock(&workqueue_lock); |
b1f4ec17 | 911 | list_del(&wq->list); |
95402b38 | 912 | spin_unlock(&workqueue_lock); |
3af24433 | 913 | |
363ab6f1 | 914 | for_each_cpu_mask_nr(cpu, *cpu_map) |
1e35eaa2 | 915 | cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu)); |
3da1c84c | 916 | cpu_maps_update_done(); |
9b41ea72 | 917 | |
3af24433 ON |
918 | free_percpu(wq->cpu_wq); |
919 | kfree(wq); | |
920 | } | |
921 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
922 | ||
923 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
924 | unsigned long action, | |
925 | void *hcpu) | |
926 | { | |
927 | unsigned int cpu = (unsigned long)hcpu; | |
928 | struct cpu_workqueue_struct *cwq; | |
929 | struct workqueue_struct *wq; | |
8448502c | 930 | int ret = NOTIFY_OK; |
3af24433 | 931 | |
8bb78442 RW |
932 | action &= ~CPU_TASKS_FROZEN; |
933 | ||
3af24433 | 934 | switch (action) { |
3af24433 | 935 | case CPU_UP_PREPARE: |
e7577c50 | 936 | cpumask_set_cpu(cpu, cpu_populated_map); |
3af24433 | 937 | } |
8448502c | 938 | undo: |
3af24433 ON |
939 | list_for_each_entry(wq, &workqueues, list) { |
940 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
941 | ||
942 | switch (action) { | |
943 | case CPU_UP_PREPARE: | |
944 | if (!create_workqueue_thread(cwq, cpu)) | |
945 | break; | |
95402b38 GS |
946 | printk(KERN_ERR "workqueue [%s] for %i failed\n", |
947 | wq->name, cpu); | |
8448502c ON |
948 | action = CPU_UP_CANCELED; |
949 | ret = NOTIFY_BAD; | |
950 | goto undo; | |
3af24433 ON |
951 | |
952 | case CPU_ONLINE: | |
06ba38a9 | 953 | start_workqueue_thread(cwq, cpu); |
3af24433 ON |
954 | break; |
955 | ||
956 | case CPU_UP_CANCELED: | |
06ba38a9 | 957 | start_workqueue_thread(cwq, -1); |
3da1c84c | 958 | case CPU_POST_DEAD: |
1e35eaa2 | 959 | cleanup_workqueue_thread(cwq); |
3af24433 ON |
960 | break; |
961 | } | |
1da177e4 LT |
962 | } |
963 | ||
00dfcaf7 ON |
964 | switch (action) { |
965 | case CPU_UP_CANCELED: | |
3da1c84c | 966 | case CPU_POST_DEAD: |
e7577c50 | 967 | cpumask_clear_cpu(cpu, cpu_populated_map); |
00dfcaf7 ON |
968 | } |
969 | ||
8448502c | 970 | return ret; |
1da177e4 | 971 | } |
1da177e4 | 972 | |
2d3854a3 | 973 | #ifdef CONFIG_SMP |
8ccad40d RR |
974 | static struct workqueue_struct *work_on_cpu_wq __read_mostly; |
975 | ||
2d3854a3 RR |
976 | struct work_for_cpu { |
977 | struct work_struct work; | |
978 | long (*fn)(void *); | |
979 | void *arg; | |
980 | long ret; | |
981 | }; | |
982 | ||
983 | static void do_work_for_cpu(struct work_struct *w) | |
984 | { | |
985 | struct work_for_cpu *wfc = container_of(w, struct work_for_cpu, work); | |
986 | ||
987 | wfc->ret = wfc->fn(wfc->arg); | |
988 | } | |
989 | ||
990 | /** | |
991 | * work_on_cpu - run a function in user context on a particular cpu | |
992 | * @cpu: the cpu to run on | |
993 | * @fn: the function to run | |
994 | * @arg: the function arg | |
995 | * | |
31ad9081 RR |
996 | * This will return the value @fn returns. |
997 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
2d3854a3 RR |
998 | */ |
999 | long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) | |
1000 | { | |
1001 | struct work_for_cpu wfc; | |
1002 | ||
1003 | INIT_WORK(&wfc.work, do_work_for_cpu); | |
1004 | wfc.fn = fn; | |
1005 | wfc.arg = arg; | |
8ccad40d | 1006 | queue_work_on(cpu, work_on_cpu_wq, &wfc.work); |
31ad9081 | 1007 | flush_work(&wfc.work); |
2d3854a3 RR |
1008 | |
1009 | return wfc.ret; | |
1010 | } | |
1011 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
1012 | #endif /* CONFIG_SMP */ | |
1013 | ||
c12920d1 | 1014 | void __init init_workqueues(void) |
1da177e4 | 1015 | { |
e7577c50 RR |
1016 | alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL); |
1017 | ||
1018 | cpumask_copy(cpu_populated_map, cpu_online_mask); | |
1019 | singlethread_cpu = cpumask_first(cpu_possible_mask); | |
1020 | cpu_singlethread_map = cpumask_of(singlethread_cpu); | |
1da177e4 LT |
1021 | hotcpu_notifier(workqueue_cpu_callback, 0); |
1022 | keventd_wq = create_workqueue("events"); | |
1023 | BUG_ON(!keventd_wq); | |
8ccad40d RR |
1024 | #ifdef CONFIG_SMP |
1025 | work_on_cpu_wq = create_workqueue("work_on_cpu"); | |
1026 | BUG_ON(!work_on_cpu_wq); | |
1027 | #endif | |
1da177e4 | 1028 | } |