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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> | |
1da177e4 LT |
35 | |
36 | /* | |
f756d5e2 NL |
37 | * The per-CPU workqueue (if single thread, we always use the first |
38 | * possible cpu). | |
1da177e4 LT |
39 | */ |
40 | struct cpu_workqueue_struct { | |
41 | ||
42 | spinlock_t lock; | |
43 | ||
1da177e4 LT |
44 | struct list_head worklist; |
45 | wait_queue_head_t more_work; | |
3af24433 | 46 | struct work_struct *current_work; |
1da177e4 LT |
47 | |
48 | struct workqueue_struct *wq; | |
36c8b586 | 49 | struct task_struct *thread; |
3af24433 | 50 | int should_stop; |
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; |
1da177e4 LT |
61 | const char *name; |
62 | struct list_head list; /* Empty if single thread */ | |
319c2a98 | 63 | int freezeable; /* Freeze threads during suspend */ |
1da177e4 LT |
64 | }; |
65 | ||
66 | /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove | |
67 | threads to each one as cpus come/go. */ | |
9b41ea72 | 68 | static DEFINE_MUTEX(workqueue_mutex); |
1da177e4 LT |
69 | static LIST_HEAD(workqueues); |
70 | ||
3af24433 | 71 | static int singlethread_cpu __read_mostly; |
b1f4ec17 | 72 | static cpumask_t cpu_singlethread_map __read_mostly; |
3af24433 ON |
73 | /* optimization, we could use cpu_possible_map */ |
74 | static cpumask_t cpu_populated_map __read_mostly; | |
f756d5e2 | 75 | |
1da177e4 LT |
76 | /* If it's single threaded, it isn't in the list of workqueues. */ |
77 | static inline int is_single_threaded(struct workqueue_struct *wq) | |
78 | { | |
79 | return list_empty(&wq->list); | |
80 | } | |
81 | ||
b1f4ec17 ON |
82 | static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq) |
83 | { | |
84 | return is_single_threaded(wq) | |
85 | ? &cpu_singlethread_map : &cpu_populated_map; | |
86 | } | |
87 | ||
4594bf15 DH |
88 | /* |
89 | * Set the workqueue on which a work item is to be run | |
90 | * - Must *only* be called if the pending flag is set | |
91 | */ | |
365970a1 DH |
92 | static inline void set_wq_data(struct work_struct *work, void *wq) |
93 | { | |
4594bf15 DH |
94 | unsigned long new; |
95 | ||
96 | BUG_ON(!work_pending(work)); | |
365970a1 | 97 | |
365970a1 | 98 | new = (unsigned long) wq | (1UL << WORK_STRUCT_PENDING); |
a08727ba LT |
99 | new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); |
100 | atomic_long_set(&work->data, new); | |
365970a1 DH |
101 | } |
102 | ||
103 | static inline void *get_wq_data(struct work_struct *work) | |
104 | { | |
a08727ba | 105 | return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); |
365970a1 DH |
106 | } |
107 | ||
b89deed3 ON |
108 | static void insert_work(struct cpu_workqueue_struct *cwq, |
109 | struct work_struct *work, int tail) | |
110 | { | |
111 | set_wq_data(work, cwq); | |
112 | if (tail) | |
113 | list_add_tail(&work->entry, &cwq->worklist); | |
114 | else | |
115 | list_add(&work->entry, &cwq->worklist); | |
116 | wake_up(&cwq->more_work); | |
117 | } | |
118 | ||
1da177e4 LT |
119 | /* Preempt must be disabled. */ |
120 | static void __queue_work(struct cpu_workqueue_struct *cwq, | |
121 | struct work_struct *work) | |
122 | { | |
123 | unsigned long flags; | |
124 | ||
125 | spin_lock_irqsave(&cwq->lock, flags); | |
b89deed3 | 126 | insert_work(cwq, work, 1); |
1da177e4 LT |
127 | spin_unlock_irqrestore(&cwq->lock, flags); |
128 | } | |
129 | ||
0fcb78c2 REB |
130 | /** |
131 | * queue_work - queue work on a workqueue | |
132 | * @wq: workqueue to use | |
133 | * @work: work to queue | |
134 | * | |
057647fc | 135 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 LT |
136 | * |
137 | * We queue the work to the CPU it was submitted, but there is no | |
138 | * guarantee that it will be processed by that CPU. | |
139 | */ | |
140 | int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) | |
141 | { | |
142 | int ret = 0, cpu = get_cpu(); | |
143 | ||
a08727ba | 144 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
1da177e4 | 145 | if (unlikely(is_single_threaded(wq))) |
f756d5e2 | 146 | cpu = singlethread_cpu; |
1da177e4 | 147 | BUG_ON(!list_empty(&work->entry)); |
89ada679 | 148 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
1da177e4 LT |
149 | ret = 1; |
150 | } | |
151 | put_cpu(); | |
152 | return ret; | |
153 | } | |
ae90dd5d | 154 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 155 | |
82f67cd9 | 156 | void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 157 | { |
52bad64d | 158 | struct delayed_work *dwork = (struct delayed_work *)__data; |
365970a1 | 159 | struct workqueue_struct *wq = get_wq_data(&dwork->work); |
1da177e4 LT |
160 | int cpu = smp_processor_id(); |
161 | ||
162 | if (unlikely(is_single_threaded(wq))) | |
f756d5e2 | 163 | cpu = singlethread_cpu; |
1da177e4 | 164 | |
52bad64d | 165 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), &dwork->work); |
1da177e4 LT |
166 | } |
167 | ||
0fcb78c2 REB |
168 | /** |
169 | * queue_delayed_work - queue work on a workqueue after delay | |
170 | * @wq: workqueue to use | |
af9997e4 | 171 | * @dwork: delayable work to queue |
0fcb78c2 REB |
172 | * @delay: number of jiffies to wait before queueing |
173 | * | |
057647fc | 174 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 175 | */ |
1da177e4 | 176 | int fastcall queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 177 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 LT |
178 | { |
179 | int ret = 0; | |
52bad64d DH |
180 | struct timer_list *timer = &dwork->timer; |
181 | struct work_struct *work = &dwork->work; | |
182 | ||
82f67cd9 | 183 | timer_stats_timer_set_start_info(timer); |
52bad64d DH |
184 | if (delay == 0) |
185 | return queue_work(wq, work); | |
1da177e4 | 186 | |
a08727ba | 187 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
1da177e4 LT |
188 | BUG_ON(timer_pending(timer)); |
189 | BUG_ON(!list_empty(&work->entry)); | |
190 | ||
191 | /* This stores wq for the moment, for the timer_fn */ | |
365970a1 | 192 | set_wq_data(work, wq); |
1da177e4 | 193 | timer->expires = jiffies + delay; |
52bad64d | 194 | timer->data = (unsigned long)dwork; |
1da177e4 LT |
195 | timer->function = delayed_work_timer_fn; |
196 | add_timer(timer); | |
197 | ret = 1; | |
198 | } | |
199 | return ret; | |
200 | } | |
ae90dd5d | 201 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 202 | |
0fcb78c2 REB |
203 | /** |
204 | * queue_delayed_work_on - queue work on specific CPU after delay | |
205 | * @cpu: CPU number to execute work on | |
206 | * @wq: workqueue to use | |
af9997e4 | 207 | * @dwork: work to queue |
0fcb78c2 REB |
208 | * @delay: number of jiffies to wait before queueing |
209 | * | |
057647fc | 210 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 211 | */ |
7a6bc1cd | 212 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 213 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
214 | { |
215 | int ret = 0; | |
52bad64d DH |
216 | struct timer_list *timer = &dwork->timer; |
217 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 218 | |
a08727ba | 219 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
7a6bc1cd VP |
220 | BUG_ON(timer_pending(timer)); |
221 | BUG_ON(!list_empty(&work->entry)); | |
222 | ||
223 | /* This stores wq for the moment, for the timer_fn */ | |
365970a1 | 224 | set_wq_data(work, wq); |
7a6bc1cd | 225 | timer->expires = jiffies + delay; |
52bad64d | 226 | timer->data = (unsigned long)dwork; |
7a6bc1cd VP |
227 | timer->function = delayed_work_timer_fn; |
228 | add_timer_on(timer, cpu); | |
229 | ret = 1; | |
230 | } | |
231 | return ret; | |
232 | } | |
ae90dd5d | 233 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 234 | |
858119e1 | 235 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 236 | { |
f293ea92 | 237 | spin_lock_irq(&cwq->lock); |
1da177e4 LT |
238 | cwq->run_depth++; |
239 | if (cwq->run_depth > 3) { | |
240 | /* morton gets to eat his hat */ | |
241 | printk("%s: recursion depth exceeded: %d\n", | |
242 | __FUNCTION__, cwq->run_depth); | |
243 | dump_stack(); | |
244 | } | |
245 | while (!list_empty(&cwq->worklist)) { | |
246 | struct work_struct *work = list_entry(cwq->worklist.next, | |
247 | struct work_struct, entry); | |
6bb49e59 | 248 | work_func_t f = work->func; |
1da177e4 | 249 | |
b89deed3 | 250 | cwq->current_work = work; |
1da177e4 | 251 | list_del_init(cwq->worklist.next); |
f293ea92 | 252 | spin_unlock_irq(&cwq->lock); |
1da177e4 | 253 | |
365970a1 | 254 | BUG_ON(get_wq_data(work) != cwq); |
a08727ba | 255 | if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work))) |
65f27f38 DH |
256 | work_release(work); |
257 | f(work); | |
1da177e4 | 258 | |
d5abe669 PZ |
259 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
260 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
261 | "%s/0x%08x/%d\n", | |
262 | current->comm, preempt_count(), | |
263 | current->pid); | |
264 | printk(KERN_ERR " last function: "); | |
265 | print_symbol("%s\n", (unsigned long)f); | |
266 | debug_show_held_locks(current); | |
267 | dump_stack(); | |
268 | } | |
269 | ||
f293ea92 | 270 | spin_lock_irq(&cwq->lock); |
b89deed3 | 271 | cwq->current_work = NULL; |
1da177e4 LT |
272 | } |
273 | cwq->run_depth--; | |
f293ea92 | 274 | spin_unlock_irq(&cwq->lock); |
1da177e4 LT |
275 | } |
276 | ||
3af24433 ON |
277 | /* |
278 | * NOTE: the caller must not touch *cwq if this func returns true | |
279 | */ | |
280 | static int cwq_should_stop(struct cpu_workqueue_struct *cwq) | |
281 | { | |
282 | int should_stop = cwq->should_stop; | |
283 | ||
284 | if (unlikely(should_stop)) { | |
285 | spin_lock_irq(&cwq->lock); | |
286 | should_stop = cwq->should_stop && list_empty(&cwq->worklist); | |
287 | if (should_stop) | |
288 | cwq->thread = NULL; | |
289 | spin_unlock_irq(&cwq->lock); | |
290 | } | |
291 | ||
292 | return should_stop; | |
293 | } | |
294 | ||
1da177e4 LT |
295 | static int worker_thread(void *__cwq) |
296 | { | |
297 | struct cpu_workqueue_struct *cwq = __cwq; | |
3af24433 | 298 | DEFINE_WAIT(wait); |
1da177e4 LT |
299 | struct k_sigaction sa; |
300 | sigset_t blocked; | |
301 | ||
319c2a98 | 302 | if (!cwq->wq->freezeable) |
341a5958 | 303 | current->flags |= PF_NOFREEZE; |
1da177e4 LT |
304 | |
305 | set_user_nice(current, -5); | |
306 | ||
307 | /* Block and flush all signals */ | |
308 | sigfillset(&blocked); | |
309 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
310 | flush_signals(current); | |
311 | ||
46934023 CL |
312 | /* |
313 | * We inherited MPOL_INTERLEAVE from the booting kernel. | |
314 | * Set MPOL_DEFAULT to insure node local allocations. | |
315 | */ | |
316 | numa_default_policy(); | |
317 | ||
1da177e4 LT |
318 | /* SIG_IGN makes children autoreap: see do_notify_parent(). */ |
319 | sa.sa.sa_handler = SIG_IGN; | |
320 | sa.sa.sa_flags = 0; | |
321 | siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); | |
322 | do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); | |
323 | ||
3af24433 | 324 | for (;;) { |
319c2a98 | 325 | if (cwq->wq->freezeable) |
341a5958 RW |
326 | try_to_freeze(); |
327 | ||
3af24433 ON |
328 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
329 | if (!cwq->should_stop && list_empty(&cwq->worklist)) | |
1da177e4 | 330 | schedule(); |
3af24433 ON |
331 | finish_wait(&cwq->more_work, &wait); |
332 | ||
333 | if (cwq_should_stop(cwq)) | |
334 | break; | |
1da177e4 | 335 | |
3af24433 | 336 | run_workqueue(cwq); |
1da177e4 | 337 | } |
3af24433 | 338 | |
1da177e4 LT |
339 | return 0; |
340 | } | |
341 | ||
fc2e4d70 ON |
342 | struct wq_barrier { |
343 | struct work_struct work; | |
344 | struct completion done; | |
345 | }; | |
346 | ||
347 | static void wq_barrier_func(struct work_struct *work) | |
348 | { | |
349 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
350 | complete(&barr->done); | |
351 | } | |
352 | ||
83c22520 ON |
353 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
354 | struct wq_barrier *barr, int tail) | |
fc2e4d70 ON |
355 | { |
356 | INIT_WORK(&barr->work, wq_barrier_func); | |
357 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); | |
358 | ||
359 | init_completion(&barr->done); | |
83c22520 ON |
360 | |
361 | insert_work(cwq, &barr->work, tail); | |
fc2e4d70 ON |
362 | } |
363 | ||
1da177e4 LT |
364 | static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
365 | { | |
366 | if (cwq->thread == current) { | |
367 | /* | |
368 | * Probably keventd trying to flush its own queue. So simply run | |
369 | * it by hand rather than deadlocking. | |
370 | */ | |
371 | run_workqueue(cwq); | |
372 | } else { | |
fc2e4d70 | 373 | struct wq_barrier barr; |
83c22520 | 374 | int active = 0; |
1da177e4 | 375 | |
83c22520 ON |
376 | spin_lock_irq(&cwq->lock); |
377 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
378 | insert_wq_barrier(cwq, &barr, 1); | |
379 | active = 1; | |
380 | } | |
381 | spin_unlock_irq(&cwq->lock); | |
1da177e4 | 382 | |
d721304d | 383 | if (active) |
83c22520 | 384 | wait_for_completion(&barr.done); |
1da177e4 LT |
385 | } |
386 | } | |
387 | ||
0fcb78c2 | 388 | /** |
1da177e4 | 389 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 390 | * @wq: workqueue to flush |
1da177e4 LT |
391 | * |
392 | * Forces execution of the workqueue and blocks until its completion. | |
393 | * This is typically used in driver shutdown handlers. | |
394 | * | |
fc2e4d70 ON |
395 | * We sleep until all works which were queued on entry have been handled, |
396 | * but we are not livelocked by new incoming ones. | |
1da177e4 LT |
397 | * |
398 | * This function used to run the workqueues itself. Now we just wait for the | |
399 | * helper threads to do it. | |
400 | */ | |
401 | void fastcall flush_workqueue(struct workqueue_struct *wq) | |
402 | { | |
b1f4ec17 ON |
403 | const cpumask_t *cpu_map = wq_cpu_map(wq); |
404 | int cpu | |
1da177e4 | 405 | |
b1f4ec17 ON |
406 | might_sleep(); |
407 | for_each_cpu_mask(cpu, *cpu_map) | |
408 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); | |
1da177e4 | 409 | } |
ae90dd5d | 410 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 411 | |
b89deed3 ON |
412 | static void wait_on_work(struct cpu_workqueue_struct *cwq, |
413 | struct work_struct *work) | |
414 | { | |
415 | struct wq_barrier barr; | |
416 | int running = 0; | |
417 | ||
418 | spin_lock_irq(&cwq->lock); | |
419 | if (unlikely(cwq->current_work == work)) { | |
83c22520 | 420 | insert_wq_barrier(cwq, &barr, 0); |
b89deed3 ON |
421 | running = 1; |
422 | } | |
423 | spin_unlock_irq(&cwq->lock); | |
424 | ||
3af24433 | 425 | if (unlikely(running)) |
b89deed3 | 426 | wait_for_completion(&barr.done); |
b89deed3 ON |
427 | } |
428 | ||
429 | /** | |
430 | * flush_work - block until a work_struct's callback has terminated | |
431 | * @wq: the workqueue on which the work is queued | |
432 | * @work: the work which is to be flushed | |
433 | * | |
434 | * flush_work() will attempt to cancel the work if it is queued. If the work's | |
435 | * callback appears to be running, flush_work() will block until it has | |
436 | * completed. | |
437 | * | |
438 | * flush_work() is designed to be used when the caller is tearing down data | |
439 | * structures which the callback function operates upon. It is expected that, | |
440 | * prior to calling flush_work(), the caller has arranged for the work to not | |
441 | * be requeued. | |
442 | */ | |
443 | void flush_work(struct workqueue_struct *wq, struct work_struct *work) | |
444 | { | |
b1f4ec17 | 445 | const cpumask_t *cpu_map = wq_cpu_map(wq); |
b89deed3 | 446 | struct cpu_workqueue_struct *cwq; |
b1f4ec17 | 447 | int cpu; |
b89deed3 | 448 | |
f293ea92 ON |
449 | might_sleep(); |
450 | ||
b89deed3 ON |
451 | cwq = get_wq_data(work); |
452 | /* Was it ever queued ? */ | |
453 | if (!cwq) | |
3af24433 | 454 | return; |
b89deed3 ON |
455 | |
456 | /* | |
3af24433 ON |
457 | * This work can't be re-queued, no need to re-check that |
458 | * get_wq_data() is still the same when we take cwq->lock. | |
b89deed3 ON |
459 | */ |
460 | spin_lock_irq(&cwq->lock); | |
461 | list_del_init(&work->entry); | |
462 | work_release(work); | |
463 | spin_unlock_irq(&cwq->lock); | |
464 | ||
b1f4ec17 ON |
465 | for_each_cpu_mask(cpu, *cpu_map) |
466 | wait_on_work(per_cpu_ptr(wq->cpu_wq, cpu), work); | |
b89deed3 ON |
467 | } |
468 | EXPORT_SYMBOL_GPL(flush_work); | |
469 | ||
1da177e4 LT |
470 | |
471 | static struct workqueue_struct *keventd_wq; | |
472 | ||
0fcb78c2 REB |
473 | /** |
474 | * schedule_work - put work task in global workqueue | |
475 | * @work: job to be done | |
476 | * | |
477 | * This puts a job in the kernel-global workqueue. | |
478 | */ | |
1da177e4 LT |
479 | int fastcall schedule_work(struct work_struct *work) |
480 | { | |
481 | return queue_work(keventd_wq, work); | |
482 | } | |
ae90dd5d | 483 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 484 | |
0fcb78c2 REB |
485 | /** |
486 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
487 | * @dwork: job to be done |
488 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
489 | * |
490 | * After waiting for a given time this puts a job in the kernel-global | |
491 | * workqueue. | |
492 | */ | |
82f67cd9 IM |
493 | int fastcall schedule_delayed_work(struct delayed_work *dwork, |
494 | unsigned long delay) | |
1da177e4 | 495 | { |
82f67cd9 | 496 | timer_stats_timer_set_start_info(&dwork->timer); |
52bad64d | 497 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 498 | } |
ae90dd5d | 499 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 500 | |
0fcb78c2 REB |
501 | /** |
502 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
503 | * @cpu: cpu to use | |
52bad64d | 504 | * @dwork: job to be done |
0fcb78c2 REB |
505 | * @delay: number of jiffies to wait |
506 | * | |
507 | * After waiting for a given time this puts a job in the kernel-global | |
508 | * workqueue on the specified CPU. | |
509 | */ | |
1da177e4 | 510 | int schedule_delayed_work_on(int cpu, |
52bad64d | 511 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 512 | { |
52bad64d | 513 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 514 | } |
ae90dd5d | 515 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 516 | |
b6136773 AM |
517 | /** |
518 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
519 | * @func: the function to call | |
b6136773 AM |
520 | * |
521 | * Returns zero on success. | |
522 | * Returns -ve errno on failure. | |
523 | * | |
524 | * Appears to be racy against CPU hotplug. | |
525 | * | |
526 | * schedule_on_each_cpu() is very slow. | |
527 | */ | |
65f27f38 | 528 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
529 | { |
530 | int cpu; | |
b6136773 | 531 | struct work_struct *works; |
15316ba8 | 532 | |
b6136773 AM |
533 | works = alloc_percpu(struct work_struct); |
534 | if (!works) | |
15316ba8 | 535 | return -ENOMEM; |
b6136773 | 536 | |
e18f3ffb | 537 | preempt_disable(); /* CPU hotplug */ |
15316ba8 | 538 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
539 | struct work_struct *work = per_cpu_ptr(works, cpu); |
540 | ||
541 | INIT_WORK(work, func); | |
542 | set_bit(WORK_STRUCT_PENDING, work_data_bits(work)); | |
543 | __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work); | |
15316ba8 | 544 | } |
e18f3ffb | 545 | preempt_enable(); |
15316ba8 | 546 | flush_workqueue(keventd_wq); |
b6136773 | 547 | free_percpu(works); |
15316ba8 CL |
548 | return 0; |
549 | } | |
550 | ||
1da177e4 LT |
551 | void flush_scheduled_work(void) |
552 | { | |
553 | flush_workqueue(keventd_wq); | |
554 | } | |
ae90dd5d | 555 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 556 | |
b89deed3 ON |
557 | void flush_work_keventd(struct work_struct *work) |
558 | { | |
559 | flush_work(keventd_wq, work); | |
560 | } | |
561 | EXPORT_SYMBOL(flush_work_keventd); | |
562 | ||
1da177e4 | 563 | /** |
72fd4a35 | 564 | * cancel_rearming_delayed_workqueue - reliably kill off a delayed work whose handler rearms the delayed work. |
1da177e4 | 565 | * @wq: the controlling workqueue structure |
52bad64d | 566 | * @dwork: the delayed work struct |
1da177e4 | 567 | */ |
81ddef77 | 568 | void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, |
52bad64d | 569 | struct delayed_work *dwork) |
1da177e4 | 570 | { |
dfb4b82e ON |
571 | /* Was it ever queued ? */ |
572 | if (!get_wq_data(&dwork->work)) | |
573 | return; | |
574 | ||
52bad64d | 575 | while (!cancel_delayed_work(dwork)) |
1da177e4 LT |
576 | flush_workqueue(wq); |
577 | } | |
81ddef77 | 578 | EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); |
1da177e4 LT |
579 | |
580 | /** | |
72fd4a35 | 581 | * cancel_rearming_delayed_work - reliably kill off a delayed keventd work whose handler rearms the delayed work. |
52bad64d | 582 | * @dwork: the delayed work struct |
1da177e4 | 583 | */ |
52bad64d | 584 | void cancel_rearming_delayed_work(struct delayed_work *dwork) |
1da177e4 | 585 | { |
52bad64d | 586 | cancel_rearming_delayed_workqueue(keventd_wq, dwork); |
1da177e4 LT |
587 | } |
588 | EXPORT_SYMBOL(cancel_rearming_delayed_work); | |
589 | ||
1fa44eca JB |
590 | /** |
591 | * execute_in_process_context - reliably execute the routine with user context | |
592 | * @fn: the function to execute | |
1fa44eca JB |
593 | * @ew: guaranteed storage for the execute work structure (must |
594 | * be available when the work executes) | |
595 | * | |
596 | * Executes the function immediately if process context is available, | |
597 | * otherwise schedules the function for delayed execution. | |
598 | * | |
599 | * Returns: 0 - function was executed | |
600 | * 1 - function was scheduled for execution | |
601 | */ | |
65f27f38 | 602 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
603 | { |
604 | if (!in_interrupt()) { | |
65f27f38 | 605 | fn(&ew->work); |
1fa44eca JB |
606 | return 0; |
607 | } | |
608 | ||
65f27f38 | 609 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
610 | schedule_work(&ew->work); |
611 | ||
612 | return 1; | |
613 | } | |
614 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
615 | ||
1da177e4 LT |
616 | int keventd_up(void) |
617 | { | |
618 | return keventd_wq != NULL; | |
619 | } | |
620 | ||
621 | int current_is_keventd(void) | |
622 | { | |
623 | struct cpu_workqueue_struct *cwq; | |
624 | int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ | |
625 | int ret = 0; | |
626 | ||
627 | BUG_ON(!keventd_wq); | |
628 | ||
89ada679 | 629 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
630 | if (current == cwq->thread) |
631 | ret = 1; | |
632 | ||
633 | return ret; | |
634 | ||
635 | } | |
636 | ||
3af24433 ON |
637 | static struct cpu_workqueue_struct * |
638 | init_cpu_workqueue(struct workqueue_struct *wq, int cpu) | |
1da177e4 | 639 | { |
89ada679 | 640 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 | 641 | |
3af24433 ON |
642 | cwq->wq = wq; |
643 | spin_lock_init(&cwq->lock); | |
644 | INIT_LIST_HEAD(&cwq->worklist); | |
645 | init_waitqueue_head(&cwq->more_work); | |
646 | ||
647 | return cwq; | |
1da177e4 LT |
648 | } |
649 | ||
3af24433 ON |
650 | static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
651 | { | |
652 | struct workqueue_struct *wq = cwq->wq; | |
653 | const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d"; | |
654 | struct task_struct *p; | |
655 | ||
656 | p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu); | |
657 | /* | |
658 | * Nobody can add the work_struct to this cwq, | |
659 | * if (caller is __create_workqueue) | |
660 | * nobody should see this wq | |
661 | * else // caller is CPU_UP_PREPARE | |
662 | * cpu is not on cpu_online_map | |
663 | * so we can abort safely. | |
664 | */ | |
665 | if (IS_ERR(p)) | |
666 | return PTR_ERR(p); | |
667 | ||
668 | cwq->thread = p; | |
669 | cwq->should_stop = 0; | |
670 | if (!is_single_threaded(wq)) | |
671 | kthread_bind(p, cpu); | |
672 | ||
673 | if (is_single_threaded(wq) || cpu_online(cpu)) | |
674 | wake_up_process(p); | |
675 | ||
676 | return 0; | |
677 | } | |
678 | ||
679 | struct workqueue_struct *__create_workqueue(const char *name, | |
680 | int singlethread, int freezeable) | |
1da177e4 | 681 | { |
1da177e4 | 682 | struct workqueue_struct *wq; |
3af24433 ON |
683 | struct cpu_workqueue_struct *cwq; |
684 | int err = 0, cpu; | |
1da177e4 | 685 | |
3af24433 ON |
686 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
687 | if (!wq) | |
688 | return NULL; | |
689 | ||
690 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); | |
691 | if (!wq->cpu_wq) { | |
692 | kfree(wq); | |
693 | return NULL; | |
694 | } | |
695 | ||
696 | wq->name = name; | |
697 | wq->freezeable = freezeable; | |
698 | ||
699 | if (singlethread) { | |
700 | INIT_LIST_HEAD(&wq->list); | |
701 | cwq = init_cpu_workqueue(wq, singlethread_cpu); | |
702 | err = create_workqueue_thread(cwq, singlethread_cpu); | |
703 | } else { | |
9b41ea72 | 704 | mutex_lock(&workqueue_mutex); |
3af24433 ON |
705 | list_add(&wq->list, &workqueues); |
706 | ||
707 | for_each_possible_cpu(cpu) { | |
708 | cwq = init_cpu_workqueue(wq, cpu); | |
709 | if (err || !cpu_online(cpu)) | |
710 | continue; | |
711 | err = create_workqueue_thread(cwq, cpu); | |
1da177e4 | 712 | } |
3af24433 ON |
713 | mutex_unlock(&workqueue_mutex); |
714 | } | |
715 | ||
716 | if (err) { | |
717 | destroy_workqueue(wq); | |
718 | wq = NULL; | |
719 | } | |
720 | return wq; | |
721 | } | |
722 | EXPORT_SYMBOL_GPL(__create_workqueue); | |
1da177e4 | 723 | |
3af24433 ON |
724 | static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
725 | { | |
726 | struct wq_barrier barr; | |
727 | int alive = 0; | |
89ada679 | 728 | |
3af24433 ON |
729 | spin_lock_irq(&cwq->lock); |
730 | if (cwq->thread != NULL) { | |
731 | insert_wq_barrier(cwq, &barr, 1); | |
732 | cwq->should_stop = 1; | |
733 | alive = 1; | |
734 | } | |
735 | spin_unlock_irq(&cwq->lock); | |
736 | ||
737 | if (alive) { | |
738 | wait_for_completion(&barr.done); | |
739 | ||
740 | while (unlikely(cwq->thread != NULL)) | |
741 | cpu_relax(); | |
742 | /* | |
743 | * Wait until cwq->thread unlocks cwq->lock, | |
744 | * it won't touch *cwq after that. | |
745 | */ | |
746 | smp_rmb(); | |
747 | spin_unlock_wait(&cwq->lock); | |
748 | } | |
749 | } | |
750 | ||
751 | /** | |
752 | * destroy_workqueue - safely terminate a workqueue | |
753 | * @wq: target workqueue | |
754 | * | |
755 | * Safely destroy a workqueue. All work currently pending will be done first. | |
756 | */ | |
757 | void destroy_workqueue(struct workqueue_struct *wq) | |
758 | { | |
b1f4ec17 | 759 | const cpumask_t *cpu_map = wq_cpu_map(wq); |
3af24433 | 760 | struct cpu_workqueue_struct *cwq; |
b1f4ec17 | 761 | int cpu; |
3af24433 | 762 | |
b1f4ec17 ON |
763 | mutex_lock(&workqueue_mutex); |
764 | list_del(&wq->list); | |
765 | mutex_unlock(&workqueue_mutex); | |
3af24433 | 766 | |
b1f4ec17 ON |
767 | for_each_cpu_mask(cpu, *cpu_map) { |
768 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
769 | cleanup_workqueue_thread(cwq, cpu); | |
3af24433 | 770 | } |
9b41ea72 | 771 | |
3af24433 ON |
772 | free_percpu(wq->cpu_wq); |
773 | kfree(wq); | |
774 | } | |
775 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
776 | ||
777 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
778 | unsigned long action, | |
779 | void *hcpu) | |
780 | { | |
781 | unsigned int cpu = (unsigned long)hcpu; | |
782 | struct cpu_workqueue_struct *cwq; | |
783 | struct workqueue_struct *wq; | |
784 | ||
785 | switch (action) { | |
786 | case CPU_LOCK_ACQUIRE: | |
9b41ea72 | 787 | mutex_lock(&workqueue_mutex); |
3af24433 | 788 | return NOTIFY_OK; |
9b41ea72 | 789 | |
3af24433 | 790 | case CPU_LOCK_RELEASE: |
9b41ea72 | 791 | mutex_unlock(&workqueue_mutex); |
3af24433 | 792 | return NOTIFY_OK; |
1da177e4 | 793 | |
3af24433 ON |
794 | case CPU_UP_PREPARE: |
795 | cpu_set(cpu, cpu_populated_map); | |
796 | } | |
797 | ||
798 | list_for_each_entry(wq, &workqueues, list) { | |
799 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
800 | ||
801 | switch (action) { | |
802 | case CPU_UP_PREPARE: | |
803 | if (!create_workqueue_thread(cwq, cpu)) | |
804 | break; | |
805 | printk(KERN_ERR "workqueue for %i failed\n", cpu); | |
806 | return NOTIFY_BAD; | |
807 | ||
808 | case CPU_ONLINE: | |
809 | wake_up_process(cwq->thread); | |
810 | break; | |
811 | ||
812 | case CPU_UP_CANCELED: | |
813 | if (cwq->thread) | |
814 | wake_up_process(cwq->thread); | |
815 | case CPU_DEAD: | |
816 | cleanup_workqueue_thread(cwq, cpu); | |
817 | break; | |
818 | } | |
1da177e4 LT |
819 | } |
820 | ||
821 | return NOTIFY_OK; | |
822 | } | |
1da177e4 LT |
823 | |
824 | void init_workqueues(void) | |
825 | { | |
3af24433 | 826 | cpu_populated_map = cpu_online_map; |
f756d5e2 | 827 | singlethread_cpu = first_cpu(cpu_possible_map); |
b1f4ec17 | 828 | cpu_singlethread_map = cpumask_of_cpu(singlethread_cpu); |
1da177e4 LT |
829 | hotcpu_notifier(workqueue_cpu_callback, 0); |
830 | keventd_wq = create_workqueue("events"); | |
831 | BUG_ON(!keventd_wq); | |
832 | } |