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 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 | static void __queue_work(struct cpu_workqueue_struct *cwq, |
144 | struct work_struct *work) | |
145 | { | |
146 | unsigned long flags; | |
147 | ||
148 | spin_lock_irqsave(&cwq->lock, flags); | |
b89deed3 | 149 | insert_work(cwq, work, 1); |
1da177e4 LT |
150 | spin_unlock_irqrestore(&cwq->lock, flags); |
151 | } | |
152 | ||
0fcb78c2 REB |
153 | /** |
154 | * queue_work - queue work on a workqueue | |
155 | * @wq: workqueue to use | |
156 | * @work: work to queue | |
157 | * | |
057647fc | 158 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 | 159 | * |
00dfcaf7 ON |
160 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
161 | * it can be processed by another CPU. | |
1da177e4 | 162 | */ |
7ad5b3a5 | 163 | int queue_work(struct workqueue_struct *wq, struct work_struct *work) |
1da177e4 | 164 | { |
a848e3b6 | 165 | int ret = 0; |
1da177e4 | 166 | |
a08727ba | 167 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
1da177e4 | 168 | BUG_ON(!list_empty(&work->entry)); |
a848e3b6 ON |
169 | __queue_work(wq_per_cpu(wq, get_cpu()), work); |
170 | put_cpu(); | |
1da177e4 LT |
171 | ret = 1; |
172 | } | |
1da177e4 LT |
173 | return ret; |
174 | } | |
ae90dd5d | 175 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 176 | |
c1a220e7 ZR |
177 | /** |
178 | * queue_work_on - queue work on specific cpu | |
179 | * @cpu: CPU number to execute work on | |
180 | * @wq: workqueue to use | |
181 | * @work: work to queue | |
182 | * | |
183 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
184 | * | |
185 | * We queue the work to a specific CPU, the caller must ensure it | |
186 | * can't go away. | |
187 | */ | |
188 | int | |
189 | queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) | |
190 | { | |
191 | int ret = 0; | |
192 | ||
193 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | |
194 | BUG_ON(!list_empty(&work->entry)); | |
195 | __queue_work(wq_per_cpu(wq, cpu), work); | |
196 | ret = 1; | |
197 | } | |
198 | return ret; | |
199 | } | |
200 | EXPORT_SYMBOL_GPL(queue_work_on); | |
201 | ||
6d141c3f | 202 | static void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 203 | { |
52bad64d | 204 | struct delayed_work *dwork = (struct delayed_work *)__data; |
ed7c0fee ON |
205 | struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
206 | struct workqueue_struct *wq = cwq->wq; | |
1da177e4 | 207 | |
a848e3b6 | 208 | __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work); |
1da177e4 LT |
209 | } |
210 | ||
0fcb78c2 REB |
211 | /** |
212 | * queue_delayed_work - queue work on a workqueue after delay | |
213 | * @wq: workqueue to use | |
af9997e4 | 214 | * @dwork: delayable work to queue |
0fcb78c2 REB |
215 | * @delay: number of jiffies to wait before queueing |
216 | * | |
057647fc | 217 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 218 | */ |
7ad5b3a5 | 219 | int queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 220 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 221 | { |
52bad64d | 222 | if (delay == 0) |
63bc0362 | 223 | return queue_work(wq, &dwork->work); |
1da177e4 | 224 | |
63bc0362 | 225 | return queue_delayed_work_on(-1, wq, dwork, delay); |
1da177e4 | 226 | } |
ae90dd5d | 227 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 228 | |
0fcb78c2 REB |
229 | /** |
230 | * queue_delayed_work_on - queue work on specific CPU after delay | |
231 | * @cpu: CPU number to execute work on | |
232 | * @wq: workqueue to use | |
af9997e4 | 233 | * @dwork: work to queue |
0fcb78c2 REB |
234 | * @delay: number of jiffies to wait before queueing |
235 | * | |
057647fc | 236 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 237 | */ |
7a6bc1cd | 238 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 239 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
240 | { |
241 | int ret = 0; | |
52bad64d DH |
242 | struct timer_list *timer = &dwork->timer; |
243 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 244 | |
a08727ba | 245 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
7a6bc1cd VP |
246 | BUG_ON(timer_pending(timer)); |
247 | BUG_ON(!list_empty(&work->entry)); | |
248 | ||
8a3e77cc AL |
249 | timer_stats_timer_set_start_info(&dwork->timer); |
250 | ||
ed7c0fee | 251 | /* This stores cwq for the moment, for the timer_fn */ |
a848e3b6 | 252 | set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id())); |
7a6bc1cd | 253 | timer->expires = jiffies + delay; |
52bad64d | 254 | timer->data = (unsigned long)dwork; |
7a6bc1cd | 255 | timer->function = delayed_work_timer_fn; |
63bc0362 ON |
256 | |
257 | if (unlikely(cpu >= 0)) | |
258 | add_timer_on(timer, cpu); | |
259 | else | |
260 | add_timer(timer); | |
7a6bc1cd VP |
261 | ret = 1; |
262 | } | |
263 | return ret; | |
264 | } | |
ae90dd5d | 265 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 266 | |
858119e1 | 267 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 268 | { |
f293ea92 | 269 | spin_lock_irq(&cwq->lock); |
1da177e4 LT |
270 | cwq->run_depth++; |
271 | if (cwq->run_depth > 3) { | |
272 | /* morton gets to eat his hat */ | |
273 | printk("%s: recursion depth exceeded: %d\n", | |
af1f16d0 | 274 | __func__, cwq->run_depth); |
1da177e4 LT |
275 | dump_stack(); |
276 | } | |
277 | while (!list_empty(&cwq->worklist)) { | |
278 | struct work_struct *work = list_entry(cwq->worklist.next, | |
279 | struct work_struct, entry); | |
6bb49e59 | 280 | work_func_t f = work->func; |
4e6045f1 JB |
281 | #ifdef CONFIG_LOCKDEP |
282 | /* | |
283 | * It is permissible to free the struct work_struct | |
284 | * from inside the function that is called from it, | |
285 | * this we need to take into account for lockdep too. | |
286 | * To avoid bogus "held lock freed" warnings as well | |
287 | * as problems when looking into work->lockdep_map, | |
288 | * make a copy and use that here. | |
289 | */ | |
290 | struct lockdep_map lockdep_map = work->lockdep_map; | |
291 | #endif | |
1da177e4 | 292 | |
b89deed3 | 293 | cwq->current_work = work; |
1da177e4 | 294 | list_del_init(cwq->worklist.next); |
f293ea92 | 295 | spin_unlock_irq(&cwq->lock); |
1da177e4 | 296 | |
365970a1 | 297 | BUG_ON(get_wq_data(work) != cwq); |
23b2e599 | 298 | work_clear_pending(work); |
4e6045f1 JB |
299 | lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); |
300 | lock_acquire(&lockdep_map, 0, 0, 0, 2, _THIS_IP_); | |
65f27f38 | 301 | f(work); |
4e6045f1 JB |
302 | lock_release(&lockdep_map, 1, _THIS_IP_); |
303 | lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_); | |
1da177e4 | 304 | |
d5abe669 PZ |
305 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
306 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
307 | "%s/0x%08x/%d\n", | |
308 | current->comm, preempt_count(), | |
ba25f9dc | 309 | task_pid_nr(current)); |
d5abe669 PZ |
310 | printk(KERN_ERR " last function: "); |
311 | print_symbol("%s\n", (unsigned long)f); | |
312 | debug_show_held_locks(current); | |
313 | dump_stack(); | |
314 | } | |
315 | ||
f293ea92 | 316 | spin_lock_irq(&cwq->lock); |
b89deed3 | 317 | cwq->current_work = NULL; |
1da177e4 LT |
318 | } |
319 | cwq->run_depth--; | |
f293ea92 | 320 | spin_unlock_irq(&cwq->lock); |
1da177e4 LT |
321 | } |
322 | ||
323 | static int worker_thread(void *__cwq) | |
324 | { | |
325 | struct cpu_workqueue_struct *cwq = __cwq; | |
3af24433 | 326 | DEFINE_WAIT(wait); |
1da177e4 | 327 | |
83144186 RW |
328 | if (cwq->wq->freezeable) |
329 | set_freezable(); | |
1da177e4 LT |
330 | |
331 | set_user_nice(current, -5); | |
1da177e4 | 332 | |
3af24433 | 333 | for (;;) { |
3af24433 | 334 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
14441960 ON |
335 | if (!freezing(current) && |
336 | !kthread_should_stop() && | |
337 | list_empty(&cwq->worklist)) | |
1da177e4 | 338 | schedule(); |
3af24433 ON |
339 | finish_wait(&cwq->more_work, &wait); |
340 | ||
85f4186a ON |
341 | try_to_freeze(); |
342 | ||
14441960 | 343 | if (kthread_should_stop()) |
3af24433 | 344 | break; |
1da177e4 | 345 | |
3af24433 | 346 | run_workqueue(cwq); |
1da177e4 | 347 | } |
3af24433 | 348 | |
1da177e4 LT |
349 | return 0; |
350 | } | |
351 | ||
fc2e4d70 ON |
352 | struct wq_barrier { |
353 | struct work_struct work; | |
354 | struct completion done; | |
355 | }; | |
356 | ||
357 | static void wq_barrier_func(struct work_struct *work) | |
358 | { | |
359 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
360 | complete(&barr->done); | |
361 | } | |
362 | ||
83c22520 ON |
363 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
364 | struct wq_barrier *barr, int tail) | |
fc2e4d70 ON |
365 | { |
366 | INIT_WORK(&barr->work, wq_barrier_func); | |
367 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); | |
368 | ||
369 | init_completion(&barr->done); | |
83c22520 ON |
370 | |
371 | insert_work(cwq, &barr->work, tail); | |
fc2e4d70 ON |
372 | } |
373 | ||
14441960 | 374 | static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 375 | { |
14441960 ON |
376 | int active; |
377 | ||
1da177e4 LT |
378 | if (cwq->thread == current) { |
379 | /* | |
380 | * Probably keventd trying to flush its own queue. So simply run | |
381 | * it by hand rather than deadlocking. | |
382 | */ | |
383 | run_workqueue(cwq); | |
14441960 | 384 | active = 1; |
1da177e4 | 385 | } else { |
fc2e4d70 | 386 | struct wq_barrier barr; |
1da177e4 | 387 | |
14441960 | 388 | active = 0; |
83c22520 ON |
389 | spin_lock_irq(&cwq->lock); |
390 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
391 | insert_wq_barrier(cwq, &barr, 1); | |
392 | active = 1; | |
393 | } | |
394 | spin_unlock_irq(&cwq->lock); | |
1da177e4 | 395 | |
d721304d | 396 | if (active) |
83c22520 | 397 | wait_for_completion(&barr.done); |
1da177e4 | 398 | } |
14441960 ON |
399 | |
400 | return active; | |
1da177e4 LT |
401 | } |
402 | ||
0fcb78c2 | 403 | /** |
1da177e4 | 404 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 405 | * @wq: workqueue to flush |
1da177e4 LT |
406 | * |
407 | * Forces execution of the workqueue and blocks until its completion. | |
408 | * This is typically used in driver shutdown handlers. | |
409 | * | |
fc2e4d70 ON |
410 | * We sleep until all works which were queued on entry have been handled, |
411 | * but we are not livelocked by new incoming ones. | |
1da177e4 LT |
412 | * |
413 | * This function used to run the workqueues itself. Now we just wait for the | |
414 | * helper threads to do it. | |
415 | */ | |
7ad5b3a5 | 416 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 417 | { |
b1f4ec17 | 418 | const cpumask_t *cpu_map = wq_cpu_map(wq); |
cce1a165 | 419 | int cpu; |
1da177e4 | 420 | |
b1f4ec17 | 421 | might_sleep(); |
4e6045f1 JB |
422 | lock_acquire(&wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); |
423 | lock_release(&wq->lockdep_map, 1, _THIS_IP_); | |
363ab6f1 | 424 | for_each_cpu_mask_nr(cpu, *cpu_map) |
b1f4ec17 | 425 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
1da177e4 | 426 | } |
ae90dd5d | 427 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 428 | |
6e84d644 | 429 | /* |
1f1f642e | 430 | * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, |
6e84d644 ON |
431 | * so this work can't be re-armed in any way. |
432 | */ | |
433 | static int try_to_grab_pending(struct work_struct *work) | |
434 | { | |
435 | struct cpu_workqueue_struct *cwq; | |
1f1f642e | 436 | int ret = -1; |
6e84d644 ON |
437 | |
438 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) | |
1f1f642e | 439 | return 0; |
6e84d644 ON |
440 | |
441 | /* | |
442 | * The queueing is in progress, or it is already queued. Try to | |
443 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
444 | */ | |
445 | ||
446 | cwq = get_wq_data(work); | |
447 | if (!cwq) | |
448 | return ret; | |
449 | ||
450 | spin_lock_irq(&cwq->lock); | |
451 | if (!list_empty(&work->entry)) { | |
452 | /* | |
453 | * This work is queued, but perhaps we locked the wrong cwq. | |
454 | * In that case we must see the new value after rmb(), see | |
455 | * insert_work()->wmb(). | |
456 | */ | |
457 | smp_rmb(); | |
458 | if (cwq == get_wq_data(work)) { | |
459 | list_del_init(&work->entry); | |
460 | ret = 1; | |
461 | } | |
462 | } | |
463 | spin_unlock_irq(&cwq->lock); | |
464 | ||
465 | return ret; | |
466 | } | |
467 | ||
468 | static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | |
b89deed3 ON |
469 | struct work_struct *work) |
470 | { | |
471 | struct wq_barrier barr; | |
472 | int running = 0; | |
473 | ||
474 | spin_lock_irq(&cwq->lock); | |
475 | if (unlikely(cwq->current_work == work)) { | |
83c22520 | 476 | insert_wq_barrier(cwq, &barr, 0); |
b89deed3 ON |
477 | running = 1; |
478 | } | |
479 | spin_unlock_irq(&cwq->lock); | |
480 | ||
3af24433 | 481 | if (unlikely(running)) |
b89deed3 | 482 | wait_for_completion(&barr.done); |
b89deed3 ON |
483 | } |
484 | ||
6e84d644 | 485 | static void wait_on_work(struct work_struct *work) |
b89deed3 ON |
486 | { |
487 | struct cpu_workqueue_struct *cwq; | |
28e53bdd ON |
488 | struct workqueue_struct *wq; |
489 | const cpumask_t *cpu_map; | |
b1f4ec17 | 490 | int cpu; |
b89deed3 | 491 | |
f293ea92 ON |
492 | might_sleep(); |
493 | ||
4e6045f1 JB |
494 | lock_acquire(&work->lockdep_map, 0, 0, 0, 2, _THIS_IP_); |
495 | lock_release(&work->lockdep_map, 1, _THIS_IP_); | |
496 | ||
b89deed3 | 497 | cwq = get_wq_data(work); |
b89deed3 | 498 | if (!cwq) |
3af24433 | 499 | return; |
b89deed3 | 500 | |
28e53bdd ON |
501 | wq = cwq->wq; |
502 | cpu_map = wq_cpu_map(wq); | |
503 | ||
363ab6f1 | 504 | for_each_cpu_mask_nr(cpu, *cpu_map) |
6e84d644 ON |
505 | wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
506 | } | |
507 | ||
1f1f642e ON |
508 | static int __cancel_work_timer(struct work_struct *work, |
509 | struct timer_list* timer) | |
510 | { | |
511 | int ret; | |
512 | ||
513 | do { | |
514 | ret = (timer && likely(del_timer(timer))); | |
515 | if (!ret) | |
516 | ret = try_to_grab_pending(work); | |
517 | wait_on_work(work); | |
518 | } while (unlikely(ret < 0)); | |
519 | ||
520 | work_clear_pending(work); | |
521 | return ret; | |
522 | } | |
523 | ||
6e84d644 ON |
524 | /** |
525 | * cancel_work_sync - block until a work_struct's callback has terminated | |
526 | * @work: the work which is to be flushed | |
527 | * | |
1f1f642e ON |
528 | * Returns true if @work was pending. |
529 | * | |
6e84d644 ON |
530 | * cancel_work_sync() will cancel the work if it is queued. If the work's |
531 | * callback appears to be running, cancel_work_sync() will block until it | |
532 | * has completed. | |
533 | * | |
534 | * It is possible to use this function if the work re-queues itself. It can | |
535 | * cancel the work even if it migrates to another workqueue, however in that | |
536 | * case it only guarantees that work->func() has completed on the last queued | |
537 | * workqueue. | |
538 | * | |
539 | * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not | |
540 | * pending, otherwise it goes into a busy-wait loop until the timer expires. | |
541 | * | |
542 | * The caller must ensure that workqueue_struct on which this work was last | |
543 | * queued can't be destroyed before this function returns. | |
544 | */ | |
1f1f642e | 545 | int cancel_work_sync(struct work_struct *work) |
6e84d644 | 546 | { |
1f1f642e | 547 | return __cancel_work_timer(work, NULL); |
b89deed3 | 548 | } |
28e53bdd | 549 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 550 | |
6e84d644 | 551 | /** |
f5a421a4 | 552 | * cancel_delayed_work_sync - reliably kill off a delayed work. |
6e84d644 ON |
553 | * @dwork: the delayed work struct |
554 | * | |
1f1f642e ON |
555 | * Returns true if @dwork was pending. |
556 | * | |
6e84d644 ON |
557 | * It is possible to use this function if @dwork rearms itself via queue_work() |
558 | * or queue_delayed_work(). See also the comment for cancel_work_sync(). | |
559 | */ | |
1f1f642e | 560 | int cancel_delayed_work_sync(struct delayed_work *dwork) |
6e84d644 | 561 | { |
1f1f642e | 562 | return __cancel_work_timer(&dwork->work, &dwork->timer); |
6e84d644 | 563 | } |
f5a421a4 | 564 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 565 | |
6e84d644 | 566 | static struct workqueue_struct *keventd_wq __read_mostly; |
1da177e4 | 567 | |
0fcb78c2 REB |
568 | /** |
569 | * schedule_work - put work task in global workqueue | |
570 | * @work: job to be done | |
571 | * | |
572 | * This puts a job in the kernel-global workqueue. | |
573 | */ | |
7ad5b3a5 | 574 | int schedule_work(struct work_struct *work) |
1da177e4 LT |
575 | { |
576 | return queue_work(keventd_wq, work); | |
577 | } | |
ae90dd5d | 578 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 579 | |
c1a220e7 ZR |
580 | /* |
581 | * schedule_work_on - put work task on a specific cpu | |
582 | * @cpu: cpu to put the work task on | |
583 | * @work: job to be done | |
584 | * | |
585 | * This puts a job on a specific cpu | |
586 | */ | |
587 | int schedule_work_on(int cpu, struct work_struct *work) | |
588 | { | |
589 | return queue_work_on(cpu, keventd_wq, work); | |
590 | } | |
591 | EXPORT_SYMBOL(schedule_work_on); | |
592 | ||
0fcb78c2 REB |
593 | /** |
594 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
595 | * @dwork: job to be done |
596 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
597 | * |
598 | * After waiting for a given time this puts a job in the kernel-global | |
599 | * workqueue. | |
600 | */ | |
7ad5b3a5 | 601 | int schedule_delayed_work(struct delayed_work *dwork, |
82f67cd9 | 602 | unsigned long delay) |
1da177e4 | 603 | { |
52bad64d | 604 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 605 | } |
ae90dd5d | 606 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 607 | |
0fcb78c2 REB |
608 | /** |
609 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
610 | * @cpu: cpu to use | |
52bad64d | 611 | * @dwork: job to be done |
0fcb78c2 REB |
612 | * @delay: number of jiffies to wait |
613 | * | |
614 | * After waiting for a given time this puts a job in the kernel-global | |
615 | * workqueue on the specified CPU. | |
616 | */ | |
1da177e4 | 617 | int schedule_delayed_work_on(int cpu, |
52bad64d | 618 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 619 | { |
52bad64d | 620 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 621 | } |
ae90dd5d | 622 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 623 | |
b6136773 AM |
624 | /** |
625 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
626 | * @func: the function to call | |
b6136773 AM |
627 | * |
628 | * Returns zero on success. | |
629 | * Returns -ve errno on failure. | |
630 | * | |
b6136773 AM |
631 | * schedule_on_each_cpu() is very slow. |
632 | */ | |
65f27f38 | 633 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
634 | { |
635 | int cpu; | |
b6136773 | 636 | struct work_struct *works; |
15316ba8 | 637 | |
b6136773 AM |
638 | works = alloc_percpu(struct work_struct); |
639 | if (!works) | |
15316ba8 | 640 | return -ENOMEM; |
b6136773 | 641 | |
95402b38 | 642 | get_online_cpus(); |
15316ba8 | 643 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
644 | struct work_struct *work = per_cpu_ptr(works, cpu); |
645 | ||
646 | INIT_WORK(work, func); | |
647 | set_bit(WORK_STRUCT_PENDING, work_data_bits(work)); | |
648 | __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work); | |
15316ba8 CL |
649 | } |
650 | flush_workqueue(keventd_wq); | |
95402b38 | 651 | put_online_cpus(); |
b6136773 | 652 | free_percpu(works); |
15316ba8 CL |
653 | return 0; |
654 | } | |
655 | ||
1da177e4 LT |
656 | void flush_scheduled_work(void) |
657 | { | |
658 | flush_workqueue(keventd_wq); | |
659 | } | |
ae90dd5d | 660 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 661 | |
1fa44eca JB |
662 | /** |
663 | * execute_in_process_context - reliably execute the routine with user context | |
664 | * @fn: the function to execute | |
1fa44eca JB |
665 | * @ew: guaranteed storage for the execute work structure (must |
666 | * be available when the work executes) | |
667 | * | |
668 | * Executes the function immediately if process context is available, | |
669 | * otherwise schedules the function for delayed execution. | |
670 | * | |
671 | * Returns: 0 - function was executed | |
672 | * 1 - function was scheduled for execution | |
673 | */ | |
65f27f38 | 674 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
675 | { |
676 | if (!in_interrupt()) { | |
65f27f38 | 677 | fn(&ew->work); |
1fa44eca JB |
678 | return 0; |
679 | } | |
680 | ||
65f27f38 | 681 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
682 | schedule_work(&ew->work); |
683 | ||
684 | return 1; | |
685 | } | |
686 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
687 | ||
1da177e4 LT |
688 | int keventd_up(void) |
689 | { | |
690 | return keventd_wq != NULL; | |
691 | } | |
692 | ||
693 | int current_is_keventd(void) | |
694 | { | |
695 | struct cpu_workqueue_struct *cwq; | |
d243769d | 696 | int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ |
1da177e4 LT |
697 | int ret = 0; |
698 | ||
699 | BUG_ON(!keventd_wq); | |
700 | ||
89ada679 | 701 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
702 | if (current == cwq->thread) |
703 | ret = 1; | |
704 | ||
705 | return ret; | |
706 | ||
707 | } | |
708 | ||
3af24433 ON |
709 | static struct cpu_workqueue_struct * |
710 | init_cpu_workqueue(struct workqueue_struct *wq, int cpu) | |
1da177e4 | 711 | { |
89ada679 | 712 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 | 713 | |
3af24433 ON |
714 | cwq->wq = wq; |
715 | spin_lock_init(&cwq->lock); | |
716 | INIT_LIST_HEAD(&cwq->worklist); | |
717 | init_waitqueue_head(&cwq->more_work); | |
718 | ||
719 | return cwq; | |
1da177e4 LT |
720 | } |
721 | ||
3af24433 ON |
722 | static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
723 | { | |
724 | struct workqueue_struct *wq = cwq->wq; | |
725 | const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d"; | |
726 | struct task_struct *p; | |
727 | ||
728 | p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu); | |
729 | /* | |
730 | * Nobody can add the work_struct to this cwq, | |
731 | * if (caller is __create_workqueue) | |
732 | * nobody should see this wq | |
733 | * else // caller is CPU_UP_PREPARE | |
734 | * cpu is not on cpu_online_map | |
735 | * so we can abort safely. | |
736 | */ | |
737 | if (IS_ERR(p)) | |
738 | return PTR_ERR(p); | |
739 | ||
740 | cwq->thread = p; | |
3af24433 ON |
741 | |
742 | return 0; | |
743 | } | |
744 | ||
06ba38a9 ON |
745 | static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
746 | { | |
747 | struct task_struct *p = cwq->thread; | |
748 | ||
749 | if (p != NULL) { | |
750 | if (cpu >= 0) | |
751 | kthread_bind(p, cpu); | |
752 | wake_up_process(p); | |
753 | } | |
754 | } | |
755 | ||
4e6045f1 JB |
756 | struct workqueue_struct *__create_workqueue_key(const char *name, |
757 | int singlethread, | |
758 | int freezeable, | |
eb13ba87 JB |
759 | struct lock_class_key *key, |
760 | const char *lock_name) | |
1da177e4 | 761 | { |
1da177e4 | 762 | struct workqueue_struct *wq; |
3af24433 ON |
763 | struct cpu_workqueue_struct *cwq; |
764 | int err = 0, cpu; | |
1da177e4 | 765 | |
3af24433 ON |
766 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
767 | if (!wq) | |
768 | return NULL; | |
769 | ||
770 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); | |
771 | if (!wq->cpu_wq) { | |
772 | kfree(wq); | |
773 | return NULL; | |
774 | } | |
775 | ||
776 | wq->name = name; | |
eb13ba87 | 777 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 778 | wq->singlethread = singlethread; |
3af24433 | 779 | wq->freezeable = freezeable; |
cce1a165 | 780 | INIT_LIST_HEAD(&wq->list); |
3af24433 ON |
781 | |
782 | if (singlethread) { | |
3af24433 ON |
783 | cwq = init_cpu_workqueue(wq, singlethread_cpu); |
784 | err = create_workqueue_thread(cwq, singlethread_cpu); | |
06ba38a9 | 785 | start_workqueue_thread(cwq, -1); |
3af24433 | 786 | } else { |
95402b38 GS |
787 | get_online_cpus(); |
788 | spin_lock(&workqueue_lock); | |
3af24433 | 789 | list_add(&wq->list, &workqueues); |
95402b38 | 790 | spin_unlock(&workqueue_lock); |
3af24433 ON |
791 | |
792 | for_each_possible_cpu(cpu) { | |
793 | cwq = init_cpu_workqueue(wq, cpu); | |
794 | if (err || !cpu_online(cpu)) | |
795 | continue; | |
796 | err = create_workqueue_thread(cwq, cpu); | |
06ba38a9 | 797 | start_workqueue_thread(cwq, cpu); |
1da177e4 | 798 | } |
95402b38 | 799 | put_online_cpus(); |
3af24433 ON |
800 | } |
801 | ||
802 | if (err) { | |
803 | destroy_workqueue(wq); | |
804 | wq = NULL; | |
805 | } | |
806 | return wq; | |
807 | } | |
4e6045f1 | 808 | EXPORT_SYMBOL_GPL(__create_workqueue_key); |
1da177e4 | 809 | |
1e35eaa2 | 810 | static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) |
3af24433 | 811 | { |
14441960 ON |
812 | /* |
813 | * Our caller is either destroy_workqueue() or CPU_DEAD, | |
95402b38 | 814 | * get_online_cpus() protects cwq->thread. |
14441960 ON |
815 | */ |
816 | if (cwq->thread == NULL) | |
817 | return; | |
3af24433 | 818 | |
4e6045f1 JB |
819 | lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); |
820 | lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_); | |
821 | ||
13c22168 | 822 | flush_cpu_workqueue(cwq); |
14441960 | 823 | /* |
13c22168 ON |
824 | * If the caller is CPU_DEAD and cwq->worklist was not empty, |
825 | * a concurrent flush_workqueue() can insert a barrier after us. | |
826 | * However, in that case run_workqueue() won't return and check | |
827 | * kthread_should_stop() until it flushes all work_struct's. | |
14441960 ON |
828 | * When ->worklist becomes empty it is safe to exit because no |
829 | * more work_structs can be queued on this cwq: flush_workqueue | |
830 | * checks list_empty(), and a "normal" queue_work() can't use | |
831 | * a dead CPU. | |
832 | */ | |
14441960 ON |
833 | kthread_stop(cwq->thread); |
834 | cwq->thread = NULL; | |
3af24433 ON |
835 | } |
836 | ||
837 | /** | |
838 | * destroy_workqueue - safely terminate a workqueue | |
839 | * @wq: target workqueue | |
840 | * | |
841 | * Safely destroy a workqueue. All work currently pending will be done first. | |
842 | */ | |
843 | void destroy_workqueue(struct workqueue_struct *wq) | |
844 | { | |
b1f4ec17 | 845 | const cpumask_t *cpu_map = wq_cpu_map(wq); |
b1f4ec17 | 846 | int cpu; |
3af24433 | 847 | |
95402b38 GS |
848 | get_online_cpus(); |
849 | spin_lock(&workqueue_lock); | |
b1f4ec17 | 850 | list_del(&wq->list); |
95402b38 | 851 | spin_unlock(&workqueue_lock); |
3af24433 | 852 | |
363ab6f1 | 853 | for_each_cpu_mask_nr(cpu, *cpu_map) |
1e35eaa2 | 854 | cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu)); |
00dfcaf7 | 855 | put_online_cpus(); |
9b41ea72 | 856 | |
3af24433 ON |
857 | free_percpu(wq->cpu_wq); |
858 | kfree(wq); | |
859 | } | |
860 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
861 | ||
862 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
863 | unsigned long action, | |
864 | void *hcpu) | |
865 | { | |
866 | unsigned int cpu = (unsigned long)hcpu; | |
867 | struct cpu_workqueue_struct *cwq; | |
868 | struct workqueue_struct *wq; | |
869 | ||
8bb78442 RW |
870 | action &= ~CPU_TASKS_FROZEN; |
871 | ||
3af24433 | 872 | switch (action) { |
3af24433 ON |
873 | case CPU_UP_PREPARE: |
874 | cpu_set(cpu, cpu_populated_map); | |
875 | } | |
876 | ||
877 | list_for_each_entry(wq, &workqueues, list) { | |
878 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
879 | ||
880 | switch (action) { | |
881 | case CPU_UP_PREPARE: | |
882 | if (!create_workqueue_thread(cwq, cpu)) | |
883 | break; | |
95402b38 GS |
884 | printk(KERN_ERR "workqueue [%s] for %i failed\n", |
885 | wq->name, cpu); | |
3af24433 ON |
886 | return NOTIFY_BAD; |
887 | ||
888 | case CPU_ONLINE: | |
06ba38a9 | 889 | start_workqueue_thread(cwq, cpu); |
3af24433 ON |
890 | break; |
891 | ||
892 | case CPU_UP_CANCELED: | |
06ba38a9 | 893 | start_workqueue_thread(cwq, -1); |
3af24433 | 894 | case CPU_DEAD: |
1e35eaa2 | 895 | cleanup_workqueue_thread(cwq); |
3af24433 ON |
896 | break; |
897 | } | |
1da177e4 LT |
898 | } |
899 | ||
00dfcaf7 ON |
900 | switch (action) { |
901 | case CPU_UP_CANCELED: | |
902 | case CPU_DEAD: | |
903 | cpu_clear(cpu, cpu_populated_map); | |
904 | } | |
905 | ||
1da177e4 LT |
906 | return NOTIFY_OK; |
907 | } | |
1da177e4 | 908 | |
c12920d1 | 909 | void __init init_workqueues(void) |
1da177e4 | 910 | { |
3af24433 | 911 | cpu_populated_map = cpu_online_map; |
f756d5e2 | 912 | singlethread_cpu = first_cpu(cpu_possible_map); |
b1f4ec17 | 913 | cpu_singlethread_map = cpumask_of_cpu(singlethread_cpu); |
1da177e4 LT |
914 | hotcpu_notifier(workqueue_cpu_callback, 0); |
915 | keventd_wq = create_workqueue("events"); | |
916 | BUG_ON(!keventd_wq); | |
917 | } |