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