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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> | |
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> |
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 */ |
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; |
b1f4ec17 | 75 | static cpumask_t 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 | */ | |
3af24433 | 83 | static cpumask_t cpu_populated_map __read_mostly; |
f756d5e2 | 84 | |
1da177e4 LT |
85 | /* If it's single threaded, it isn't in the list of workqueues. */ |
86 | static inline int is_single_threaded(struct workqueue_struct *wq) | |
87 | { | |
cce1a165 | 88 | return wq->singlethread; |
1da177e4 LT |
89 | } |
90 | ||
b1f4ec17 ON |
91 | static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq) |
92 | { | |
93 | return is_single_threaded(wq) | |
94 | ? &cpu_singlethread_map : &cpu_populated_map; | |
95 | } | |
96 | ||
a848e3b6 ON |
97 | static |
98 | struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu) | |
99 | { | |
100 | if (unlikely(is_single_threaded(wq))) | |
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 | ||
b89deed3 ON |
127 | static void insert_work(struct cpu_workqueue_struct *cwq, |
128 | struct work_struct *work, int tail) | |
129 | { | |
130 | set_wq_data(work, cwq); | |
6e84d644 ON |
131 | /* |
132 | * Ensure that we get the right work->data if we see the | |
133 | * result of list_add() below, see try_to_grab_pending(). | |
134 | */ | |
135 | smp_wmb(); | |
b89deed3 ON |
136 | if (tail) |
137 | list_add_tail(&work->entry, &cwq->worklist); | |
138 | else | |
139 | list_add(&work->entry, &cwq->worklist); | |
140 | wake_up(&cwq->more_work); | |
141 | } | |
142 | ||
1da177e4 LT |
143 | /* Preempt must be disabled. */ |
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); | |
b89deed3 | 150 | insert_work(cwq, work, 1); |
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 LT |
160 | * |
161 | * We queue the work to the CPU it was submitted, but there is no | |
162 | * guarantee that it will be processed by that CPU. | |
163 | */ | |
7ad5b3a5 | 164 | int queue_work(struct workqueue_struct *wq, struct work_struct *work) |
1da177e4 | 165 | { |
a848e3b6 | 166 | int ret = 0; |
1da177e4 | 167 | |
a08727ba | 168 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
1da177e4 | 169 | BUG_ON(!list_empty(&work->entry)); |
a848e3b6 ON |
170 | __queue_work(wq_per_cpu(wq, get_cpu()), work); |
171 | put_cpu(); | |
1da177e4 LT |
172 | ret = 1; |
173 | } | |
1da177e4 LT |
174 | return ret; |
175 | } | |
ae90dd5d | 176 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 177 | |
6d141c3f | 178 | static void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 179 | { |
52bad64d | 180 | struct delayed_work *dwork = (struct delayed_work *)__data; |
ed7c0fee ON |
181 | struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
182 | struct workqueue_struct *wq = cwq->wq; | |
1da177e4 | 183 | |
a848e3b6 | 184 | __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work); |
1da177e4 LT |
185 | } |
186 | ||
0fcb78c2 REB |
187 | /** |
188 | * queue_delayed_work - queue work on a workqueue after delay | |
189 | * @wq: workqueue to use | |
af9997e4 | 190 | * @dwork: delayable work to queue |
0fcb78c2 REB |
191 | * @delay: number of jiffies to wait before queueing |
192 | * | |
057647fc | 193 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 194 | */ |
7ad5b3a5 | 195 | int queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 196 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 197 | { |
63bc0362 | 198 | timer_stats_timer_set_start_info(&dwork->timer); |
52bad64d | 199 | if (delay == 0) |
63bc0362 | 200 | return queue_work(wq, &dwork->work); |
1da177e4 | 201 | |
63bc0362 | 202 | return queue_delayed_work_on(-1, wq, dwork, delay); |
1da177e4 | 203 | } |
ae90dd5d | 204 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 205 | |
0fcb78c2 REB |
206 | /** |
207 | * queue_delayed_work_on - queue work on specific CPU after delay | |
208 | * @cpu: CPU number to execute work on | |
209 | * @wq: workqueue to use | |
af9997e4 | 210 | * @dwork: work to queue |
0fcb78c2 REB |
211 | * @delay: number of jiffies to wait before queueing |
212 | * | |
057647fc | 213 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 214 | */ |
7a6bc1cd | 215 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 216 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
217 | { |
218 | int ret = 0; | |
52bad64d DH |
219 | struct timer_list *timer = &dwork->timer; |
220 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 221 | |
a08727ba | 222 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
7a6bc1cd VP |
223 | BUG_ON(timer_pending(timer)); |
224 | BUG_ON(!list_empty(&work->entry)); | |
225 | ||
ed7c0fee | 226 | /* This stores cwq for the moment, for the timer_fn */ |
a848e3b6 | 227 | set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id())); |
7a6bc1cd | 228 | timer->expires = jiffies + delay; |
52bad64d | 229 | timer->data = (unsigned long)dwork; |
7a6bc1cd | 230 | timer->function = delayed_work_timer_fn; |
63bc0362 ON |
231 | |
232 | if (unlikely(cpu >= 0)) | |
233 | add_timer_on(timer, cpu); | |
234 | else | |
235 | add_timer(timer); | |
7a6bc1cd VP |
236 | ret = 1; |
237 | } | |
238 | return ret; | |
239 | } | |
ae90dd5d | 240 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 241 | |
858119e1 | 242 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 243 | { |
f293ea92 | 244 | spin_lock_irq(&cwq->lock); |
1da177e4 LT |
245 | cwq->run_depth++; |
246 | if (cwq->run_depth > 3) { | |
247 | /* morton gets to eat his hat */ | |
248 | printk("%s: recursion depth exceeded: %d\n", | |
249 | __FUNCTION__, cwq->run_depth); | |
250 | dump_stack(); | |
251 | } | |
252 | while (!list_empty(&cwq->worklist)) { | |
253 | struct work_struct *work = list_entry(cwq->worklist.next, | |
254 | struct work_struct, entry); | |
6bb49e59 | 255 | work_func_t f = work->func; |
4e6045f1 JB |
256 | #ifdef CONFIG_LOCKDEP |
257 | /* | |
258 | * It is permissible to free the struct work_struct | |
259 | * from inside the function that is called from it, | |
260 | * this we need to take into account for lockdep too. | |
261 | * To avoid bogus "held lock freed" warnings as well | |
262 | * as problems when looking into work->lockdep_map, | |
263 | * make a copy and use that here. | |
264 | */ | |
265 | struct lockdep_map lockdep_map = work->lockdep_map; | |
266 | #endif | |
1da177e4 | 267 | |
b89deed3 | 268 | cwq->current_work = work; |
1da177e4 | 269 | list_del_init(cwq->worklist.next); |
f293ea92 | 270 | spin_unlock_irq(&cwq->lock); |
1da177e4 | 271 | |
365970a1 | 272 | BUG_ON(get_wq_data(work) != cwq); |
23b2e599 | 273 | work_clear_pending(work); |
4e6045f1 JB |
274 | lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); |
275 | lock_acquire(&lockdep_map, 0, 0, 0, 2, _THIS_IP_); | |
65f27f38 | 276 | f(work); |
4e6045f1 JB |
277 | lock_release(&lockdep_map, 1, _THIS_IP_); |
278 | lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_); | |
1da177e4 | 279 | |
d5abe669 PZ |
280 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
281 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
282 | "%s/0x%08x/%d\n", | |
283 | current->comm, preempt_count(), | |
ba25f9dc | 284 | task_pid_nr(current)); |
d5abe669 PZ |
285 | printk(KERN_ERR " last function: "); |
286 | print_symbol("%s\n", (unsigned long)f); | |
287 | debug_show_held_locks(current); | |
288 | dump_stack(); | |
289 | } | |
290 | ||
f293ea92 | 291 | spin_lock_irq(&cwq->lock); |
b89deed3 | 292 | cwq->current_work = NULL; |
1da177e4 LT |
293 | } |
294 | cwq->run_depth--; | |
f293ea92 | 295 | spin_unlock_irq(&cwq->lock); |
1da177e4 LT |
296 | } |
297 | ||
298 | static int worker_thread(void *__cwq) | |
299 | { | |
300 | struct cpu_workqueue_struct *cwq = __cwq; | |
3af24433 | 301 | DEFINE_WAIT(wait); |
1da177e4 | 302 | |
83144186 RW |
303 | if (cwq->wq->freezeable) |
304 | set_freezable(); | |
1da177e4 LT |
305 | |
306 | set_user_nice(current, -5); | |
1da177e4 | 307 | |
3af24433 | 308 | for (;;) { |
3af24433 | 309 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
14441960 ON |
310 | if (!freezing(current) && |
311 | !kthread_should_stop() && | |
312 | list_empty(&cwq->worklist)) | |
1da177e4 | 313 | schedule(); |
3af24433 ON |
314 | finish_wait(&cwq->more_work, &wait); |
315 | ||
85f4186a ON |
316 | try_to_freeze(); |
317 | ||
14441960 | 318 | if (kthread_should_stop()) |
3af24433 | 319 | break; |
1da177e4 | 320 | |
3af24433 | 321 | run_workqueue(cwq); |
1da177e4 | 322 | } |
3af24433 | 323 | |
1da177e4 LT |
324 | return 0; |
325 | } | |
326 | ||
fc2e4d70 ON |
327 | struct wq_barrier { |
328 | struct work_struct work; | |
329 | struct completion done; | |
330 | }; | |
331 | ||
332 | static void wq_barrier_func(struct work_struct *work) | |
333 | { | |
334 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
335 | complete(&barr->done); | |
336 | } | |
337 | ||
83c22520 ON |
338 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
339 | struct wq_barrier *barr, int tail) | |
fc2e4d70 ON |
340 | { |
341 | INIT_WORK(&barr->work, wq_barrier_func); | |
342 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); | |
343 | ||
344 | init_completion(&barr->done); | |
83c22520 ON |
345 | |
346 | insert_work(cwq, &barr->work, tail); | |
fc2e4d70 ON |
347 | } |
348 | ||
14441960 | 349 | static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 350 | { |
14441960 ON |
351 | int active; |
352 | ||
1da177e4 LT |
353 | if (cwq->thread == current) { |
354 | /* | |
355 | * Probably keventd trying to flush its own queue. So simply run | |
356 | * it by hand rather than deadlocking. | |
357 | */ | |
358 | run_workqueue(cwq); | |
14441960 | 359 | active = 1; |
1da177e4 | 360 | } else { |
fc2e4d70 | 361 | struct wq_barrier barr; |
1da177e4 | 362 | |
14441960 | 363 | active = 0; |
83c22520 ON |
364 | spin_lock_irq(&cwq->lock); |
365 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
366 | insert_wq_barrier(cwq, &barr, 1); | |
367 | active = 1; | |
368 | } | |
369 | spin_unlock_irq(&cwq->lock); | |
1da177e4 | 370 | |
d721304d | 371 | if (active) |
83c22520 | 372 | wait_for_completion(&barr.done); |
1da177e4 | 373 | } |
14441960 ON |
374 | |
375 | return active; | |
1da177e4 LT |
376 | } |
377 | ||
0fcb78c2 | 378 | /** |
1da177e4 | 379 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 380 | * @wq: workqueue to flush |
1da177e4 LT |
381 | * |
382 | * Forces execution of the workqueue and blocks until its completion. | |
383 | * This is typically used in driver shutdown handlers. | |
384 | * | |
fc2e4d70 ON |
385 | * We sleep until all works which were queued on entry have been handled, |
386 | * but we are not livelocked by new incoming ones. | |
1da177e4 LT |
387 | * |
388 | * This function used to run the workqueues itself. Now we just wait for the | |
389 | * helper threads to do it. | |
390 | */ | |
7ad5b3a5 | 391 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 392 | { |
b1f4ec17 | 393 | const cpumask_t *cpu_map = wq_cpu_map(wq); |
cce1a165 | 394 | int cpu; |
1da177e4 | 395 | |
b1f4ec17 | 396 | might_sleep(); |
4e6045f1 JB |
397 | lock_acquire(&wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); |
398 | lock_release(&wq->lockdep_map, 1, _THIS_IP_); | |
b1f4ec17 ON |
399 | for_each_cpu_mask(cpu, *cpu_map) |
400 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); | |
1da177e4 | 401 | } |
ae90dd5d | 402 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 403 | |
6e84d644 | 404 | /* |
1f1f642e | 405 | * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, |
6e84d644 ON |
406 | * so this work can't be re-armed in any way. |
407 | */ | |
408 | static int try_to_grab_pending(struct work_struct *work) | |
409 | { | |
410 | struct cpu_workqueue_struct *cwq; | |
1f1f642e | 411 | int ret = -1; |
6e84d644 ON |
412 | |
413 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) | |
1f1f642e | 414 | return 0; |
6e84d644 ON |
415 | |
416 | /* | |
417 | * The queueing is in progress, or it is already queued. Try to | |
418 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
419 | */ | |
420 | ||
421 | cwq = get_wq_data(work); | |
422 | if (!cwq) | |
423 | return ret; | |
424 | ||
425 | spin_lock_irq(&cwq->lock); | |
426 | if (!list_empty(&work->entry)) { | |
427 | /* | |
428 | * This work is queued, but perhaps we locked the wrong cwq. | |
429 | * In that case we must see the new value after rmb(), see | |
430 | * insert_work()->wmb(). | |
431 | */ | |
432 | smp_rmb(); | |
433 | if (cwq == get_wq_data(work)) { | |
434 | list_del_init(&work->entry); | |
435 | ret = 1; | |
436 | } | |
437 | } | |
438 | spin_unlock_irq(&cwq->lock); | |
439 | ||
440 | return ret; | |
441 | } | |
442 | ||
443 | static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | |
b89deed3 ON |
444 | struct work_struct *work) |
445 | { | |
446 | struct wq_barrier barr; | |
447 | int running = 0; | |
448 | ||
449 | spin_lock_irq(&cwq->lock); | |
450 | if (unlikely(cwq->current_work == work)) { | |
83c22520 | 451 | insert_wq_barrier(cwq, &barr, 0); |
b89deed3 ON |
452 | running = 1; |
453 | } | |
454 | spin_unlock_irq(&cwq->lock); | |
455 | ||
3af24433 | 456 | if (unlikely(running)) |
b89deed3 | 457 | wait_for_completion(&barr.done); |
b89deed3 ON |
458 | } |
459 | ||
6e84d644 | 460 | static void wait_on_work(struct work_struct *work) |
b89deed3 ON |
461 | { |
462 | struct cpu_workqueue_struct *cwq; | |
28e53bdd ON |
463 | struct workqueue_struct *wq; |
464 | const cpumask_t *cpu_map; | |
b1f4ec17 | 465 | int cpu; |
b89deed3 | 466 | |
f293ea92 ON |
467 | might_sleep(); |
468 | ||
4e6045f1 JB |
469 | lock_acquire(&work->lockdep_map, 0, 0, 0, 2, _THIS_IP_); |
470 | lock_release(&work->lockdep_map, 1, _THIS_IP_); | |
471 | ||
b89deed3 | 472 | cwq = get_wq_data(work); |
b89deed3 | 473 | if (!cwq) |
3af24433 | 474 | return; |
b89deed3 | 475 | |
28e53bdd ON |
476 | wq = cwq->wq; |
477 | cpu_map = wq_cpu_map(wq); | |
478 | ||
b1f4ec17 | 479 | for_each_cpu_mask(cpu, *cpu_map) |
6e84d644 ON |
480 | wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
481 | } | |
482 | ||
1f1f642e ON |
483 | static int __cancel_work_timer(struct work_struct *work, |
484 | struct timer_list* timer) | |
485 | { | |
486 | int ret; | |
487 | ||
488 | do { | |
489 | ret = (timer && likely(del_timer(timer))); | |
490 | if (!ret) | |
491 | ret = try_to_grab_pending(work); | |
492 | wait_on_work(work); | |
493 | } while (unlikely(ret < 0)); | |
494 | ||
495 | work_clear_pending(work); | |
496 | return ret; | |
497 | } | |
498 | ||
6e84d644 ON |
499 | /** |
500 | * cancel_work_sync - block until a work_struct's callback has terminated | |
501 | * @work: the work which is to be flushed | |
502 | * | |
1f1f642e ON |
503 | * Returns true if @work was pending. |
504 | * | |
6e84d644 ON |
505 | * cancel_work_sync() will cancel the work if it is queued. If the work's |
506 | * callback appears to be running, cancel_work_sync() will block until it | |
507 | * has completed. | |
508 | * | |
509 | * It is possible to use this function if the work re-queues itself. It can | |
510 | * cancel the work even if it migrates to another workqueue, however in that | |
511 | * case it only guarantees that work->func() has completed on the last queued | |
512 | * workqueue. | |
513 | * | |
514 | * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not | |
515 | * pending, otherwise it goes into a busy-wait loop until the timer expires. | |
516 | * | |
517 | * The caller must ensure that workqueue_struct on which this work was last | |
518 | * queued can't be destroyed before this function returns. | |
519 | */ | |
1f1f642e | 520 | int cancel_work_sync(struct work_struct *work) |
6e84d644 | 521 | { |
1f1f642e | 522 | return __cancel_work_timer(work, NULL); |
b89deed3 | 523 | } |
28e53bdd | 524 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 525 | |
6e84d644 | 526 | /** |
f5a421a4 | 527 | * cancel_delayed_work_sync - reliably kill off a delayed work. |
6e84d644 ON |
528 | * @dwork: the delayed work struct |
529 | * | |
1f1f642e ON |
530 | * Returns true if @dwork was pending. |
531 | * | |
6e84d644 ON |
532 | * It is possible to use this function if @dwork rearms itself via queue_work() |
533 | * or queue_delayed_work(). See also the comment for cancel_work_sync(). | |
534 | */ | |
1f1f642e | 535 | int cancel_delayed_work_sync(struct delayed_work *dwork) |
6e84d644 | 536 | { |
1f1f642e | 537 | return __cancel_work_timer(&dwork->work, &dwork->timer); |
6e84d644 | 538 | } |
f5a421a4 | 539 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 540 | |
6e84d644 | 541 | static struct workqueue_struct *keventd_wq __read_mostly; |
1da177e4 | 542 | |
0fcb78c2 REB |
543 | /** |
544 | * schedule_work - put work task in global workqueue | |
545 | * @work: job to be done | |
546 | * | |
547 | * This puts a job in the kernel-global workqueue. | |
548 | */ | |
7ad5b3a5 | 549 | int schedule_work(struct work_struct *work) |
1da177e4 LT |
550 | { |
551 | return queue_work(keventd_wq, work); | |
552 | } | |
ae90dd5d | 553 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 554 | |
0fcb78c2 REB |
555 | /** |
556 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
557 | * @dwork: job to be done |
558 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
559 | * |
560 | * After waiting for a given time this puts a job in the kernel-global | |
561 | * workqueue. | |
562 | */ | |
7ad5b3a5 | 563 | int schedule_delayed_work(struct delayed_work *dwork, |
82f67cd9 | 564 | unsigned long delay) |
1da177e4 | 565 | { |
82f67cd9 | 566 | timer_stats_timer_set_start_info(&dwork->timer); |
52bad64d | 567 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 568 | } |
ae90dd5d | 569 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 570 | |
0fcb78c2 REB |
571 | /** |
572 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
573 | * @cpu: cpu to use | |
52bad64d | 574 | * @dwork: job to be done |
0fcb78c2 REB |
575 | * @delay: number of jiffies to wait |
576 | * | |
577 | * After waiting for a given time this puts a job in the kernel-global | |
578 | * workqueue on the specified CPU. | |
579 | */ | |
1da177e4 | 580 | int schedule_delayed_work_on(int cpu, |
52bad64d | 581 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 582 | { |
52bad64d | 583 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 584 | } |
ae90dd5d | 585 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 586 | |
b6136773 AM |
587 | /** |
588 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
589 | * @func: the function to call | |
b6136773 AM |
590 | * |
591 | * Returns zero on success. | |
592 | * Returns -ve errno on failure. | |
593 | * | |
b6136773 AM |
594 | * schedule_on_each_cpu() is very slow. |
595 | */ | |
65f27f38 | 596 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
597 | { |
598 | int cpu; | |
b6136773 | 599 | struct work_struct *works; |
15316ba8 | 600 | |
b6136773 AM |
601 | works = alloc_percpu(struct work_struct); |
602 | if (!works) | |
15316ba8 | 603 | return -ENOMEM; |
b6136773 | 604 | |
95402b38 | 605 | get_online_cpus(); |
15316ba8 | 606 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
607 | struct work_struct *work = per_cpu_ptr(works, cpu); |
608 | ||
609 | INIT_WORK(work, func); | |
610 | set_bit(WORK_STRUCT_PENDING, work_data_bits(work)); | |
611 | __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work); | |
15316ba8 CL |
612 | } |
613 | flush_workqueue(keventd_wq); | |
95402b38 | 614 | put_online_cpus(); |
b6136773 | 615 | free_percpu(works); |
15316ba8 CL |
616 | return 0; |
617 | } | |
618 | ||
1da177e4 LT |
619 | void flush_scheduled_work(void) |
620 | { | |
621 | flush_workqueue(keventd_wq); | |
622 | } | |
ae90dd5d | 623 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 624 | |
1fa44eca JB |
625 | /** |
626 | * execute_in_process_context - reliably execute the routine with user context | |
627 | * @fn: the function to execute | |
1fa44eca JB |
628 | * @ew: guaranteed storage for the execute work structure (must |
629 | * be available when the work executes) | |
630 | * | |
631 | * Executes the function immediately if process context is available, | |
632 | * otherwise schedules the function for delayed execution. | |
633 | * | |
634 | * Returns: 0 - function was executed | |
635 | * 1 - function was scheduled for execution | |
636 | */ | |
65f27f38 | 637 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
638 | { |
639 | if (!in_interrupt()) { | |
65f27f38 | 640 | fn(&ew->work); |
1fa44eca JB |
641 | return 0; |
642 | } | |
643 | ||
65f27f38 | 644 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
645 | schedule_work(&ew->work); |
646 | ||
647 | return 1; | |
648 | } | |
649 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
650 | ||
1da177e4 LT |
651 | int keventd_up(void) |
652 | { | |
653 | return keventd_wq != NULL; | |
654 | } | |
655 | ||
656 | int current_is_keventd(void) | |
657 | { | |
658 | struct cpu_workqueue_struct *cwq; | |
d243769d | 659 | int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ |
1da177e4 LT |
660 | int ret = 0; |
661 | ||
662 | BUG_ON(!keventd_wq); | |
663 | ||
89ada679 | 664 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
665 | if (current == cwq->thread) |
666 | ret = 1; | |
667 | ||
668 | return ret; | |
669 | ||
670 | } | |
671 | ||
3af24433 ON |
672 | static struct cpu_workqueue_struct * |
673 | init_cpu_workqueue(struct workqueue_struct *wq, int cpu) | |
1da177e4 | 674 | { |
89ada679 | 675 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 | 676 | |
3af24433 ON |
677 | cwq->wq = wq; |
678 | spin_lock_init(&cwq->lock); | |
679 | INIT_LIST_HEAD(&cwq->worklist); | |
680 | init_waitqueue_head(&cwq->more_work); | |
681 | ||
682 | return cwq; | |
1da177e4 LT |
683 | } |
684 | ||
3af24433 ON |
685 | static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
686 | { | |
687 | struct workqueue_struct *wq = cwq->wq; | |
688 | const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d"; | |
689 | struct task_struct *p; | |
690 | ||
691 | p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu); | |
692 | /* | |
693 | * Nobody can add the work_struct to this cwq, | |
694 | * if (caller is __create_workqueue) | |
695 | * nobody should see this wq | |
696 | * else // caller is CPU_UP_PREPARE | |
697 | * cpu is not on cpu_online_map | |
698 | * so we can abort safely. | |
699 | */ | |
700 | if (IS_ERR(p)) | |
701 | return PTR_ERR(p); | |
702 | ||
703 | cwq->thread = p; | |
3af24433 ON |
704 | |
705 | return 0; | |
706 | } | |
707 | ||
06ba38a9 ON |
708 | static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
709 | { | |
710 | struct task_struct *p = cwq->thread; | |
711 | ||
712 | if (p != NULL) { | |
713 | if (cpu >= 0) | |
714 | kthread_bind(p, cpu); | |
715 | wake_up_process(p); | |
716 | } | |
717 | } | |
718 | ||
4e6045f1 JB |
719 | struct workqueue_struct *__create_workqueue_key(const char *name, |
720 | int singlethread, | |
721 | int freezeable, | |
eb13ba87 JB |
722 | struct lock_class_key *key, |
723 | const char *lock_name) | |
1da177e4 | 724 | { |
1da177e4 | 725 | struct workqueue_struct *wq; |
3af24433 ON |
726 | struct cpu_workqueue_struct *cwq; |
727 | int err = 0, cpu; | |
1da177e4 | 728 | |
3af24433 ON |
729 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
730 | if (!wq) | |
731 | return NULL; | |
732 | ||
733 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); | |
734 | if (!wq->cpu_wq) { | |
735 | kfree(wq); | |
736 | return NULL; | |
737 | } | |
738 | ||
739 | wq->name = name; | |
eb13ba87 | 740 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 741 | wq->singlethread = singlethread; |
3af24433 | 742 | wq->freezeable = freezeable; |
cce1a165 | 743 | INIT_LIST_HEAD(&wq->list); |
3af24433 ON |
744 | |
745 | if (singlethread) { | |
3af24433 ON |
746 | cwq = init_cpu_workqueue(wq, singlethread_cpu); |
747 | err = create_workqueue_thread(cwq, singlethread_cpu); | |
06ba38a9 | 748 | start_workqueue_thread(cwq, -1); |
3af24433 | 749 | } else { |
95402b38 GS |
750 | get_online_cpus(); |
751 | spin_lock(&workqueue_lock); | |
3af24433 | 752 | list_add(&wq->list, &workqueues); |
95402b38 | 753 | spin_unlock(&workqueue_lock); |
3af24433 ON |
754 | |
755 | for_each_possible_cpu(cpu) { | |
756 | cwq = init_cpu_workqueue(wq, cpu); | |
757 | if (err || !cpu_online(cpu)) | |
758 | continue; | |
759 | err = create_workqueue_thread(cwq, cpu); | |
06ba38a9 | 760 | start_workqueue_thread(cwq, cpu); |
1da177e4 | 761 | } |
95402b38 | 762 | put_online_cpus(); |
3af24433 ON |
763 | } |
764 | ||
765 | if (err) { | |
766 | destroy_workqueue(wq); | |
767 | wq = NULL; | |
768 | } | |
769 | return wq; | |
770 | } | |
4e6045f1 | 771 | EXPORT_SYMBOL_GPL(__create_workqueue_key); |
1da177e4 | 772 | |
3af24433 ON |
773 | static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
774 | { | |
14441960 ON |
775 | /* |
776 | * Our caller is either destroy_workqueue() or CPU_DEAD, | |
95402b38 | 777 | * get_online_cpus() protects cwq->thread. |
14441960 ON |
778 | */ |
779 | if (cwq->thread == NULL) | |
780 | return; | |
3af24433 | 781 | |
4e6045f1 JB |
782 | lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); |
783 | lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_); | |
784 | ||
13c22168 | 785 | flush_cpu_workqueue(cwq); |
14441960 | 786 | /* |
13c22168 ON |
787 | * If the caller is CPU_DEAD and cwq->worklist was not empty, |
788 | * a concurrent flush_workqueue() can insert a barrier after us. | |
789 | * However, in that case run_workqueue() won't return and check | |
790 | * kthread_should_stop() until it flushes all work_struct's. | |
14441960 ON |
791 | * When ->worklist becomes empty it is safe to exit because no |
792 | * more work_structs can be queued on this cwq: flush_workqueue | |
793 | * checks list_empty(), and a "normal" queue_work() can't use | |
794 | * a dead CPU. | |
795 | */ | |
14441960 ON |
796 | kthread_stop(cwq->thread); |
797 | cwq->thread = NULL; | |
3af24433 ON |
798 | } |
799 | ||
800 | /** | |
801 | * destroy_workqueue - safely terminate a workqueue | |
802 | * @wq: target workqueue | |
803 | * | |
804 | * Safely destroy a workqueue. All work currently pending will be done first. | |
805 | */ | |
806 | void destroy_workqueue(struct workqueue_struct *wq) | |
807 | { | |
b1f4ec17 | 808 | const cpumask_t *cpu_map = wq_cpu_map(wq); |
3af24433 | 809 | struct cpu_workqueue_struct *cwq; |
b1f4ec17 | 810 | int cpu; |
3af24433 | 811 | |
95402b38 GS |
812 | get_online_cpus(); |
813 | spin_lock(&workqueue_lock); | |
b1f4ec17 | 814 | list_del(&wq->list); |
95402b38 GS |
815 | spin_unlock(&workqueue_lock); |
816 | put_online_cpus(); | |
3af24433 | 817 | |
b1f4ec17 ON |
818 | for_each_cpu_mask(cpu, *cpu_map) { |
819 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
820 | cleanup_workqueue_thread(cwq, cpu); | |
3af24433 | 821 | } |
9b41ea72 | 822 | |
3af24433 ON |
823 | free_percpu(wq->cpu_wq); |
824 | kfree(wq); | |
825 | } | |
826 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
827 | ||
828 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
829 | unsigned long action, | |
830 | void *hcpu) | |
831 | { | |
832 | unsigned int cpu = (unsigned long)hcpu; | |
833 | struct cpu_workqueue_struct *cwq; | |
834 | struct workqueue_struct *wq; | |
835 | ||
8bb78442 RW |
836 | action &= ~CPU_TASKS_FROZEN; |
837 | ||
3af24433 | 838 | switch (action) { |
1da177e4 | 839 | |
3af24433 ON |
840 | case CPU_UP_PREPARE: |
841 | cpu_set(cpu, cpu_populated_map); | |
842 | } | |
843 | ||
844 | list_for_each_entry(wq, &workqueues, list) { | |
845 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
846 | ||
847 | switch (action) { | |
848 | case CPU_UP_PREPARE: | |
849 | if (!create_workqueue_thread(cwq, cpu)) | |
850 | break; | |
95402b38 GS |
851 | printk(KERN_ERR "workqueue [%s] for %i failed\n", |
852 | wq->name, cpu); | |
3af24433 ON |
853 | return NOTIFY_BAD; |
854 | ||
855 | case CPU_ONLINE: | |
06ba38a9 | 856 | start_workqueue_thread(cwq, cpu); |
3af24433 ON |
857 | break; |
858 | ||
859 | case CPU_UP_CANCELED: | |
06ba38a9 | 860 | start_workqueue_thread(cwq, -1); |
3af24433 ON |
861 | case CPU_DEAD: |
862 | cleanup_workqueue_thread(cwq, cpu); | |
863 | break; | |
864 | } | |
1da177e4 LT |
865 | } |
866 | ||
867 | return NOTIFY_OK; | |
868 | } | |
1da177e4 | 869 | |
c12920d1 | 870 | void __init init_workqueues(void) |
1da177e4 | 871 | { |
3af24433 | 872 | cpu_populated_map = cpu_online_map; |
f756d5e2 | 873 | singlethread_cpu = first_cpu(cpu_possible_map); |
b1f4ec17 | 874 | cpu_singlethread_map = cpumask_of_cpu(singlethread_cpu); |
1da177e4 LT |
875 | hotcpu_notifier(workqueue_cpu_callback, 0); |
876 | keventd_wq = create_workqueue("events"); | |
877 | BUG_ON(!keventd_wq); | |
878 | } |