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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/workqueue.c | |
3 | * | |
4 | * Generic mechanism for defining kernel helper threads for running | |
5 | * arbitrary tasks in process context. | |
6 | * | |
7 | * Started by Ingo Molnar, Copyright (C) 2002 | |
8 | * | |
9 | * Derived from the taskqueue/keventd code by: | |
10 | * | |
11 | * David Woodhouse <dwmw2@infradead.org> | |
12 | * Andrew Morton <andrewm@uow.edu.au> | |
13 | * Kai Petzke <wpp@marie.physik.tu-berlin.de> | |
14 | * Theodore Ts'o <tytso@mit.edu> | |
89ada679 CL |
15 | * |
16 | * Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>. | |
1da177e4 LT |
17 | */ |
18 | ||
19 | #include <linux/module.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/sched.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/signal.h> | |
24 | #include <linux/completion.h> | |
25 | #include <linux/workqueue.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/cpu.h> | |
28 | #include <linux/notifier.h> | |
29 | #include <linux/kthread.h> | |
1fa44eca | 30 | #include <linux/hardirq.h> |
46934023 | 31 | #include <linux/mempolicy.h> |
341a5958 | 32 | #include <linux/freezer.h> |
d5abe669 PZ |
33 | #include <linux/kallsyms.h> |
34 | #include <linux/debug_locks.h> | |
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; | |
1da177e4 LT |
46 | |
47 | struct workqueue_struct *wq; | |
36c8b586 | 48 | struct task_struct *thread; |
b89deed3 | 49 | struct work_struct *current_work; |
1da177e4 LT |
50 | |
51 | int run_depth; /* Detect run_workqueue() recursion depth */ | |
52 | } ____cacheline_aligned; | |
53 | ||
54 | /* | |
55 | * The externally visible workqueue abstraction is an array of | |
56 | * per-CPU workqueues: | |
57 | */ | |
58 | struct workqueue_struct { | |
89ada679 | 59 | struct cpu_workqueue_struct *cpu_wq; |
1da177e4 LT |
60 | const char *name; |
61 | struct list_head list; /* Empty if single thread */ | |
319c2a98 | 62 | int freezeable; /* Freeze threads during suspend */ |
1da177e4 LT |
63 | }; |
64 | ||
65 | /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove | |
66 | threads to each one as cpus come/go. */ | |
d721304d | 67 | static long migrate_sequence __read_mostly; |
9b41ea72 | 68 | static DEFINE_MUTEX(workqueue_mutex); |
1da177e4 LT |
69 | static LIST_HEAD(workqueues); |
70 | ||
f756d5e2 NL |
71 | static int singlethread_cpu; |
72 | ||
1da177e4 LT |
73 | /* If it's single threaded, it isn't in the list of workqueues. */ |
74 | static inline int is_single_threaded(struct workqueue_struct *wq) | |
75 | { | |
76 | return list_empty(&wq->list); | |
77 | } | |
78 | ||
4594bf15 DH |
79 | /* |
80 | * Set the workqueue on which a work item is to be run | |
81 | * - Must *only* be called if the pending flag is set | |
82 | */ | |
365970a1 DH |
83 | static inline void set_wq_data(struct work_struct *work, void *wq) |
84 | { | |
4594bf15 DH |
85 | unsigned long new; |
86 | ||
87 | BUG_ON(!work_pending(work)); | |
365970a1 | 88 | |
365970a1 | 89 | new = (unsigned long) wq | (1UL << WORK_STRUCT_PENDING); |
a08727ba LT |
90 | new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); |
91 | atomic_long_set(&work->data, new); | |
365970a1 DH |
92 | } |
93 | ||
94 | static inline void *get_wq_data(struct work_struct *work) | |
95 | { | |
a08727ba | 96 | return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); |
365970a1 DH |
97 | } |
98 | ||
68380b58 LT |
99 | static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work) |
100 | { | |
101 | int ret = 0; | |
102 | unsigned long flags; | |
103 | ||
104 | spin_lock_irqsave(&cwq->lock, flags); | |
105 | /* | |
106 | * We need to re-validate the work info after we've gotten | |
107 | * the cpu_workqueue lock. We can run the work now iff: | |
108 | * | |
109 | * - the wq_data still matches the cpu_workqueue_struct | |
110 | * - AND the work is still marked pending | |
111 | * - AND the work is still on a list (which will be this | |
112 | * workqueue_struct list) | |
113 | * | |
114 | * All these conditions are important, because we | |
115 | * need to protect against the work being run right | |
116 | * now on another CPU (all but the last one might be | |
117 | * true if it's currently running and has not been | |
118 | * released yet, for example). | |
119 | */ | |
120 | if (get_wq_data(work) == cwq | |
121 | && work_pending(work) | |
122 | && !list_empty(&work->entry)) { | |
123 | work_func_t f = work->func; | |
b89deed3 | 124 | cwq->current_work = work; |
68380b58 LT |
125 | list_del_init(&work->entry); |
126 | spin_unlock_irqrestore(&cwq->lock, flags); | |
127 | ||
a08727ba | 128 | if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work))) |
68380b58 LT |
129 | work_release(work); |
130 | f(work); | |
131 | ||
132 | spin_lock_irqsave(&cwq->lock, flags); | |
b89deed3 | 133 | cwq->current_work = NULL; |
68380b58 LT |
134 | ret = 1; |
135 | } | |
136 | spin_unlock_irqrestore(&cwq->lock, flags); | |
137 | return ret; | |
138 | } | |
139 | ||
140 | /** | |
141 | * run_scheduled_work - run scheduled work synchronously | |
142 | * @work: work to run | |
143 | * | |
144 | * This checks if the work was pending, and runs it | |
145 | * synchronously if so. It returns a boolean to indicate | |
146 | * whether it had any scheduled work to run or not. | |
147 | * | |
148 | * NOTE! This _only_ works for normal work_structs. You | |
149 | * CANNOT use this for delayed work, because the wq data | |
150 | * for delayed work will not point properly to the per- | |
151 | * CPU workqueue struct, but will change! | |
152 | */ | |
153 | int fastcall run_scheduled_work(struct work_struct *work) | |
154 | { | |
155 | for (;;) { | |
156 | struct cpu_workqueue_struct *cwq; | |
157 | ||
158 | if (!work_pending(work)) | |
159 | return 0; | |
160 | if (list_empty(&work->entry)) | |
161 | return 0; | |
162 | /* NOTE! This depends intimately on __queue_work! */ | |
163 | cwq = get_wq_data(work); | |
164 | if (!cwq) | |
165 | return 0; | |
166 | if (__run_work(cwq, work)) | |
167 | return 1; | |
168 | } | |
169 | } | |
170 | EXPORT_SYMBOL(run_scheduled_work); | |
171 | ||
b89deed3 ON |
172 | static void insert_work(struct cpu_workqueue_struct *cwq, |
173 | struct work_struct *work, int tail) | |
174 | { | |
175 | set_wq_data(work, cwq); | |
176 | if (tail) | |
177 | list_add_tail(&work->entry, &cwq->worklist); | |
178 | else | |
179 | list_add(&work->entry, &cwq->worklist); | |
180 | wake_up(&cwq->more_work); | |
181 | } | |
182 | ||
1da177e4 LT |
183 | /* Preempt must be disabled. */ |
184 | static void __queue_work(struct cpu_workqueue_struct *cwq, | |
185 | struct work_struct *work) | |
186 | { | |
187 | unsigned long flags; | |
188 | ||
189 | spin_lock_irqsave(&cwq->lock, flags); | |
b89deed3 | 190 | insert_work(cwq, work, 1); |
1da177e4 LT |
191 | spin_unlock_irqrestore(&cwq->lock, flags); |
192 | } | |
193 | ||
0fcb78c2 REB |
194 | /** |
195 | * queue_work - queue work on a workqueue | |
196 | * @wq: workqueue to use | |
197 | * @work: work to queue | |
198 | * | |
057647fc | 199 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 LT |
200 | * |
201 | * We queue the work to the CPU it was submitted, but there is no | |
202 | * guarantee that it will be processed by that CPU. | |
203 | */ | |
204 | int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) | |
205 | { | |
206 | int ret = 0, cpu = get_cpu(); | |
207 | ||
a08727ba | 208 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
1da177e4 | 209 | if (unlikely(is_single_threaded(wq))) |
f756d5e2 | 210 | cpu = singlethread_cpu; |
1da177e4 | 211 | BUG_ON(!list_empty(&work->entry)); |
89ada679 | 212 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
1da177e4 LT |
213 | ret = 1; |
214 | } | |
215 | put_cpu(); | |
216 | return ret; | |
217 | } | |
ae90dd5d | 218 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 219 | |
82f67cd9 | 220 | void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 221 | { |
52bad64d | 222 | struct delayed_work *dwork = (struct delayed_work *)__data; |
365970a1 | 223 | struct workqueue_struct *wq = get_wq_data(&dwork->work); |
1da177e4 LT |
224 | int cpu = smp_processor_id(); |
225 | ||
226 | if (unlikely(is_single_threaded(wq))) | |
f756d5e2 | 227 | cpu = singlethread_cpu; |
1da177e4 | 228 | |
52bad64d | 229 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), &dwork->work); |
1da177e4 LT |
230 | } |
231 | ||
0fcb78c2 REB |
232 | /** |
233 | * queue_delayed_work - queue work on a workqueue after delay | |
234 | * @wq: workqueue to use | |
af9997e4 | 235 | * @dwork: delayable work to queue |
0fcb78c2 REB |
236 | * @delay: number of jiffies to wait before queueing |
237 | * | |
057647fc | 238 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 239 | */ |
1da177e4 | 240 | int fastcall queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 241 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 LT |
242 | { |
243 | int ret = 0; | |
52bad64d DH |
244 | struct timer_list *timer = &dwork->timer; |
245 | struct work_struct *work = &dwork->work; | |
246 | ||
82f67cd9 | 247 | timer_stats_timer_set_start_info(timer); |
52bad64d DH |
248 | if (delay == 0) |
249 | return queue_work(wq, work); | |
1da177e4 | 250 | |
a08727ba | 251 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
1da177e4 LT |
252 | BUG_ON(timer_pending(timer)); |
253 | BUG_ON(!list_empty(&work->entry)); | |
254 | ||
255 | /* This stores wq for the moment, for the timer_fn */ | |
365970a1 | 256 | set_wq_data(work, wq); |
1da177e4 | 257 | timer->expires = jiffies + delay; |
52bad64d | 258 | timer->data = (unsigned long)dwork; |
1da177e4 LT |
259 | timer->function = delayed_work_timer_fn; |
260 | add_timer(timer); | |
261 | ret = 1; | |
262 | } | |
263 | return ret; | |
264 | } | |
ae90dd5d | 265 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 266 | |
0fcb78c2 REB |
267 | /** |
268 | * queue_delayed_work_on - queue work on specific CPU after delay | |
269 | * @cpu: CPU number to execute work on | |
270 | * @wq: workqueue to use | |
af9997e4 | 271 | * @dwork: work to queue |
0fcb78c2 REB |
272 | * @delay: number of jiffies to wait before queueing |
273 | * | |
057647fc | 274 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 275 | */ |
7a6bc1cd | 276 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 277 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
278 | { |
279 | int ret = 0; | |
52bad64d DH |
280 | struct timer_list *timer = &dwork->timer; |
281 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 282 | |
a08727ba | 283 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
7a6bc1cd VP |
284 | BUG_ON(timer_pending(timer)); |
285 | BUG_ON(!list_empty(&work->entry)); | |
286 | ||
287 | /* This stores wq for the moment, for the timer_fn */ | |
365970a1 | 288 | set_wq_data(work, wq); |
7a6bc1cd | 289 | timer->expires = jiffies + delay; |
52bad64d | 290 | timer->data = (unsigned long)dwork; |
7a6bc1cd VP |
291 | timer->function = delayed_work_timer_fn; |
292 | add_timer_on(timer, cpu); | |
293 | ret = 1; | |
294 | } | |
295 | return ret; | |
296 | } | |
ae90dd5d | 297 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 298 | |
858119e1 | 299 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 LT |
300 | { |
301 | unsigned long flags; | |
302 | ||
303 | /* | |
304 | * Keep taking off work from the queue until | |
305 | * done. | |
306 | */ | |
307 | spin_lock_irqsave(&cwq->lock, flags); | |
308 | cwq->run_depth++; | |
309 | if (cwq->run_depth > 3) { | |
310 | /* morton gets to eat his hat */ | |
311 | printk("%s: recursion depth exceeded: %d\n", | |
312 | __FUNCTION__, cwq->run_depth); | |
313 | dump_stack(); | |
314 | } | |
315 | while (!list_empty(&cwq->worklist)) { | |
316 | struct work_struct *work = list_entry(cwq->worklist.next, | |
317 | struct work_struct, entry); | |
6bb49e59 | 318 | work_func_t f = work->func; |
1da177e4 | 319 | |
b89deed3 | 320 | cwq->current_work = work; |
1da177e4 LT |
321 | list_del_init(cwq->worklist.next); |
322 | spin_unlock_irqrestore(&cwq->lock, flags); | |
323 | ||
365970a1 | 324 | BUG_ON(get_wq_data(work) != cwq); |
a08727ba | 325 | if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work))) |
65f27f38 DH |
326 | work_release(work); |
327 | f(work); | |
1da177e4 | 328 | |
d5abe669 PZ |
329 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
330 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
331 | "%s/0x%08x/%d\n", | |
332 | current->comm, preempt_count(), | |
333 | current->pid); | |
334 | printk(KERN_ERR " last function: "); | |
335 | print_symbol("%s\n", (unsigned long)f); | |
336 | debug_show_held_locks(current); | |
337 | dump_stack(); | |
338 | } | |
339 | ||
1da177e4 | 340 | spin_lock_irqsave(&cwq->lock, flags); |
b89deed3 | 341 | cwq->current_work = NULL; |
1da177e4 LT |
342 | } |
343 | cwq->run_depth--; | |
344 | spin_unlock_irqrestore(&cwq->lock, flags); | |
345 | } | |
346 | ||
347 | static int worker_thread(void *__cwq) | |
348 | { | |
349 | struct cpu_workqueue_struct *cwq = __cwq; | |
350 | DECLARE_WAITQUEUE(wait, current); | |
351 | struct k_sigaction sa; | |
352 | sigset_t blocked; | |
353 | ||
319c2a98 | 354 | if (!cwq->wq->freezeable) |
341a5958 | 355 | current->flags |= PF_NOFREEZE; |
1da177e4 LT |
356 | |
357 | set_user_nice(current, -5); | |
358 | ||
359 | /* Block and flush all signals */ | |
360 | sigfillset(&blocked); | |
361 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
362 | flush_signals(current); | |
363 | ||
46934023 CL |
364 | /* |
365 | * We inherited MPOL_INTERLEAVE from the booting kernel. | |
366 | * Set MPOL_DEFAULT to insure node local allocations. | |
367 | */ | |
368 | numa_default_policy(); | |
369 | ||
1da177e4 LT |
370 | /* SIG_IGN makes children autoreap: see do_notify_parent(). */ |
371 | sa.sa.sa_handler = SIG_IGN; | |
372 | sa.sa.sa_flags = 0; | |
373 | siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); | |
374 | do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); | |
375 | ||
376 | set_current_state(TASK_INTERRUPTIBLE); | |
377 | while (!kthread_should_stop()) { | |
319c2a98 | 378 | if (cwq->wq->freezeable) |
341a5958 RW |
379 | try_to_freeze(); |
380 | ||
1da177e4 LT |
381 | add_wait_queue(&cwq->more_work, &wait); |
382 | if (list_empty(&cwq->worklist)) | |
383 | schedule(); | |
384 | else | |
385 | __set_current_state(TASK_RUNNING); | |
386 | remove_wait_queue(&cwq->more_work, &wait); | |
387 | ||
388 | if (!list_empty(&cwq->worklist)) | |
389 | run_workqueue(cwq); | |
390 | set_current_state(TASK_INTERRUPTIBLE); | |
391 | } | |
392 | __set_current_state(TASK_RUNNING); | |
393 | return 0; | |
394 | } | |
395 | ||
fc2e4d70 ON |
396 | struct wq_barrier { |
397 | struct work_struct work; | |
398 | struct completion done; | |
399 | }; | |
400 | ||
401 | static void wq_barrier_func(struct work_struct *work) | |
402 | { | |
403 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
404 | complete(&barr->done); | |
405 | } | |
406 | ||
83c22520 ON |
407 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
408 | struct wq_barrier *barr, int tail) | |
fc2e4d70 ON |
409 | { |
410 | INIT_WORK(&barr->work, wq_barrier_func); | |
411 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); | |
412 | ||
413 | init_completion(&barr->done); | |
83c22520 ON |
414 | |
415 | insert_work(cwq, &barr->work, tail); | |
fc2e4d70 ON |
416 | } |
417 | ||
1da177e4 LT |
418 | static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
419 | { | |
420 | if (cwq->thread == current) { | |
421 | /* | |
422 | * Probably keventd trying to flush its own queue. So simply run | |
423 | * it by hand rather than deadlocking. | |
424 | */ | |
425 | run_workqueue(cwq); | |
426 | } else { | |
fc2e4d70 | 427 | struct wq_barrier barr; |
83c22520 | 428 | int active = 0; |
1da177e4 | 429 | |
83c22520 ON |
430 | spin_lock_irq(&cwq->lock); |
431 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
432 | insert_wq_barrier(cwq, &barr, 1); | |
433 | active = 1; | |
434 | } | |
435 | spin_unlock_irq(&cwq->lock); | |
1da177e4 | 436 | |
d721304d | 437 | if (active) |
83c22520 | 438 | wait_for_completion(&barr.done); |
1da177e4 LT |
439 | } |
440 | } | |
441 | ||
0fcb78c2 | 442 | /** |
1da177e4 | 443 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 444 | * @wq: workqueue to flush |
1da177e4 LT |
445 | * |
446 | * Forces execution of the workqueue and blocks until its completion. | |
447 | * This is typically used in driver shutdown handlers. | |
448 | * | |
fc2e4d70 ON |
449 | * We sleep until all works which were queued on entry have been handled, |
450 | * but we are not livelocked by new incoming ones. | |
1da177e4 LT |
451 | * |
452 | * This function used to run the workqueues itself. Now we just wait for the | |
453 | * helper threads to do it. | |
454 | */ | |
455 | void fastcall flush_workqueue(struct workqueue_struct *wq) | |
456 | { | |
1da177e4 | 457 | if (is_single_threaded(wq)) { |
bce61dd4 | 458 | /* Always use first cpu's area. */ |
f756d5e2 | 459 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu)); |
1da177e4 | 460 | } else { |
d721304d | 461 | long sequence; |
1da177e4 | 462 | int cpu; |
d721304d ON |
463 | again: |
464 | sequence = migrate_sequence; | |
1da177e4 | 465 | |
d721304d | 466 | for_each_possible_cpu(cpu) |
89ada679 | 467 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
d721304d ON |
468 | |
469 | if (unlikely(sequence != migrate_sequence)) | |
470 | goto again; | |
1da177e4 LT |
471 | } |
472 | } | |
ae90dd5d | 473 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 474 | |
b89deed3 ON |
475 | static void wait_on_work(struct cpu_workqueue_struct *cwq, |
476 | struct work_struct *work) | |
477 | { | |
478 | struct wq_barrier barr; | |
479 | int running = 0; | |
480 | ||
481 | spin_lock_irq(&cwq->lock); | |
482 | if (unlikely(cwq->current_work == work)) { | |
83c22520 | 483 | insert_wq_barrier(cwq, &barr, 0); |
b89deed3 ON |
484 | running = 1; |
485 | } | |
486 | spin_unlock_irq(&cwq->lock); | |
487 | ||
488 | if (unlikely(running)) { | |
489 | mutex_unlock(&workqueue_mutex); | |
490 | wait_for_completion(&barr.done); | |
491 | mutex_lock(&workqueue_mutex); | |
492 | } | |
493 | } | |
494 | ||
495 | /** | |
496 | * flush_work - block until a work_struct's callback has terminated | |
497 | * @wq: the workqueue on which the work is queued | |
498 | * @work: the work which is to be flushed | |
499 | * | |
500 | * flush_work() will attempt to cancel the work if it is queued. If the work's | |
501 | * callback appears to be running, flush_work() will block until it has | |
502 | * completed. | |
503 | * | |
504 | * flush_work() is designed to be used when the caller is tearing down data | |
505 | * structures which the callback function operates upon. It is expected that, | |
506 | * prior to calling flush_work(), the caller has arranged for the work to not | |
507 | * be requeued. | |
508 | */ | |
509 | void flush_work(struct workqueue_struct *wq, struct work_struct *work) | |
510 | { | |
511 | struct cpu_workqueue_struct *cwq; | |
512 | ||
513 | mutex_lock(&workqueue_mutex); | |
514 | cwq = get_wq_data(work); | |
515 | /* Was it ever queued ? */ | |
516 | if (!cwq) | |
517 | goto out; | |
518 | ||
519 | /* | |
520 | * This work can't be re-queued, and the lock above protects us | |
521 | * from take_over_work(), no need to re-check that get_wq_data() | |
522 | * is still the same when we take cwq->lock. | |
523 | */ | |
524 | spin_lock_irq(&cwq->lock); | |
525 | list_del_init(&work->entry); | |
526 | work_release(work); | |
527 | spin_unlock_irq(&cwq->lock); | |
528 | ||
529 | if (is_single_threaded(wq)) { | |
530 | /* Always use first cpu's area. */ | |
531 | wait_on_work(per_cpu_ptr(wq->cpu_wq, singlethread_cpu), work); | |
532 | } else { | |
533 | int cpu; | |
534 | ||
535 | for_each_online_cpu(cpu) | |
536 | wait_on_work(per_cpu_ptr(wq->cpu_wq, cpu), work); | |
537 | } | |
538 | out: | |
539 | mutex_unlock(&workqueue_mutex); | |
540 | } | |
541 | EXPORT_SYMBOL_GPL(flush_work); | |
542 | ||
d721304d | 543 | static void init_cpu_workqueue(struct workqueue_struct *wq, int cpu) |
1da177e4 | 544 | { |
89ada679 | 545 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 | 546 | |
1da177e4 | 547 | cwq->wq = wq; |
d721304d | 548 | spin_lock_init(&cwq->lock); |
1da177e4 LT |
549 | INIT_LIST_HEAD(&cwq->worklist); |
550 | init_waitqueue_head(&cwq->more_work); | |
d721304d ON |
551 | } |
552 | ||
553 | static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, | |
554 | int cpu) | |
555 | { | |
556 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
557 | struct task_struct *p; | |
1da177e4 LT |
558 | |
559 | if (is_single_threaded(wq)) | |
560 | p = kthread_create(worker_thread, cwq, "%s", wq->name); | |
561 | else | |
562 | p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); | |
563 | if (IS_ERR(p)) | |
564 | return NULL; | |
565 | cwq->thread = p; | |
566 | return p; | |
567 | } | |
568 | ||
569 | struct workqueue_struct *__create_workqueue(const char *name, | |
341a5958 | 570 | int singlethread, int freezeable) |
1da177e4 LT |
571 | { |
572 | int cpu, destroy = 0; | |
573 | struct workqueue_struct *wq; | |
574 | struct task_struct *p; | |
575 | ||
dd392710 | 576 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
1da177e4 LT |
577 | if (!wq) |
578 | return NULL; | |
1da177e4 | 579 | |
89ada679 | 580 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); |
676121fc BC |
581 | if (!wq->cpu_wq) { |
582 | kfree(wq); | |
583 | return NULL; | |
584 | } | |
585 | ||
1da177e4 | 586 | wq->name = name; |
319c2a98 ON |
587 | wq->freezeable = freezeable; |
588 | ||
9b41ea72 | 589 | mutex_lock(&workqueue_mutex); |
1da177e4 LT |
590 | if (singlethread) { |
591 | INIT_LIST_HEAD(&wq->list); | |
d721304d | 592 | init_cpu_workqueue(wq, singlethread_cpu); |
319c2a98 | 593 | p = create_workqueue_thread(wq, singlethread_cpu); |
1da177e4 LT |
594 | if (!p) |
595 | destroy = 1; | |
596 | else | |
597 | wake_up_process(p); | |
598 | } else { | |
1da177e4 | 599 | list_add(&wq->list, &workqueues); |
d721304d ON |
600 | for_each_possible_cpu(cpu) { |
601 | init_cpu_workqueue(wq, cpu); | |
602 | if (!cpu_online(cpu)) | |
603 | continue; | |
604 | ||
319c2a98 | 605 | p = create_workqueue_thread(wq, cpu); |
1da177e4 LT |
606 | if (p) { |
607 | kthread_bind(p, cpu); | |
608 | wake_up_process(p); | |
609 | } else | |
610 | destroy = 1; | |
611 | } | |
612 | } | |
9b41ea72 | 613 | mutex_unlock(&workqueue_mutex); |
1da177e4 LT |
614 | |
615 | /* | |
616 | * Was there any error during startup? If yes then clean up: | |
617 | */ | |
618 | if (destroy) { | |
619 | destroy_workqueue(wq); | |
620 | wq = NULL; | |
621 | } | |
622 | return wq; | |
623 | } | |
ae90dd5d | 624 | EXPORT_SYMBOL_GPL(__create_workqueue); |
1da177e4 LT |
625 | |
626 | static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) | |
627 | { | |
36aa9dfc | 628 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 | 629 | |
36aa9dfc ON |
630 | if (cwq->thread) { |
631 | kthread_stop(cwq->thread); | |
632 | cwq->thread = NULL; | |
633 | } | |
1da177e4 LT |
634 | } |
635 | ||
0fcb78c2 REB |
636 | /** |
637 | * destroy_workqueue - safely terminate a workqueue | |
638 | * @wq: target workqueue | |
639 | * | |
640 | * Safely destroy a workqueue. All work currently pending will be done first. | |
641 | */ | |
1da177e4 LT |
642 | void destroy_workqueue(struct workqueue_struct *wq) |
643 | { | |
644 | int cpu; | |
645 | ||
646 | flush_workqueue(wq); | |
647 | ||
648 | /* We don't need the distraction of CPUs appearing and vanishing. */ | |
9b41ea72 | 649 | mutex_lock(&workqueue_mutex); |
1da177e4 | 650 | if (is_single_threaded(wq)) |
f756d5e2 | 651 | cleanup_workqueue_thread(wq, singlethread_cpu); |
1da177e4 LT |
652 | else { |
653 | for_each_online_cpu(cpu) | |
654 | cleanup_workqueue_thread(wq, cpu); | |
1da177e4 | 655 | list_del(&wq->list); |
1da177e4 | 656 | } |
9b41ea72 | 657 | mutex_unlock(&workqueue_mutex); |
89ada679 | 658 | free_percpu(wq->cpu_wq); |
1da177e4 LT |
659 | kfree(wq); |
660 | } | |
ae90dd5d | 661 | EXPORT_SYMBOL_GPL(destroy_workqueue); |
1da177e4 LT |
662 | |
663 | static struct workqueue_struct *keventd_wq; | |
664 | ||
0fcb78c2 REB |
665 | /** |
666 | * schedule_work - put work task in global workqueue | |
667 | * @work: job to be done | |
668 | * | |
669 | * This puts a job in the kernel-global workqueue. | |
670 | */ | |
1da177e4 LT |
671 | int fastcall schedule_work(struct work_struct *work) |
672 | { | |
673 | return queue_work(keventd_wq, work); | |
674 | } | |
ae90dd5d | 675 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 676 | |
0fcb78c2 REB |
677 | /** |
678 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
679 | * @dwork: job to be done |
680 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
681 | * |
682 | * After waiting for a given time this puts a job in the kernel-global | |
683 | * workqueue. | |
684 | */ | |
82f67cd9 IM |
685 | int fastcall schedule_delayed_work(struct delayed_work *dwork, |
686 | unsigned long delay) | |
1da177e4 | 687 | { |
82f67cd9 | 688 | timer_stats_timer_set_start_info(&dwork->timer); |
52bad64d | 689 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 690 | } |
ae90dd5d | 691 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 692 | |
0fcb78c2 REB |
693 | /** |
694 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
695 | * @cpu: cpu to use | |
52bad64d | 696 | * @dwork: job to be done |
0fcb78c2 REB |
697 | * @delay: number of jiffies to wait |
698 | * | |
699 | * After waiting for a given time this puts a job in the kernel-global | |
700 | * workqueue on the specified CPU. | |
701 | */ | |
1da177e4 | 702 | int schedule_delayed_work_on(int cpu, |
52bad64d | 703 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 704 | { |
52bad64d | 705 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 706 | } |
ae90dd5d | 707 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 708 | |
b6136773 AM |
709 | /** |
710 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
711 | * @func: the function to call | |
b6136773 AM |
712 | * |
713 | * Returns zero on success. | |
714 | * Returns -ve errno on failure. | |
715 | * | |
716 | * Appears to be racy against CPU hotplug. | |
717 | * | |
718 | * schedule_on_each_cpu() is very slow. | |
719 | */ | |
65f27f38 | 720 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
721 | { |
722 | int cpu; | |
b6136773 | 723 | struct work_struct *works; |
15316ba8 | 724 | |
b6136773 AM |
725 | works = alloc_percpu(struct work_struct); |
726 | if (!works) | |
15316ba8 | 727 | return -ENOMEM; |
b6136773 | 728 | |
e18f3ffb | 729 | preempt_disable(); /* CPU hotplug */ |
15316ba8 | 730 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
731 | struct work_struct *work = per_cpu_ptr(works, cpu); |
732 | ||
733 | INIT_WORK(work, func); | |
734 | set_bit(WORK_STRUCT_PENDING, work_data_bits(work)); | |
735 | __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work); | |
15316ba8 | 736 | } |
e18f3ffb | 737 | preempt_enable(); |
15316ba8 | 738 | flush_workqueue(keventd_wq); |
b6136773 | 739 | free_percpu(works); |
15316ba8 CL |
740 | return 0; |
741 | } | |
742 | ||
1da177e4 LT |
743 | void flush_scheduled_work(void) |
744 | { | |
745 | flush_workqueue(keventd_wq); | |
746 | } | |
ae90dd5d | 747 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 748 | |
b89deed3 ON |
749 | void flush_work_keventd(struct work_struct *work) |
750 | { | |
751 | flush_work(keventd_wq, work); | |
752 | } | |
753 | EXPORT_SYMBOL(flush_work_keventd); | |
754 | ||
1da177e4 | 755 | /** |
72fd4a35 | 756 | * cancel_rearming_delayed_workqueue - reliably kill off a delayed work whose handler rearms the delayed work. |
1da177e4 | 757 | * @wq: the controlling workqueue structure |
52bad64d | 758 | * @dwork: the delayed work struct |
1da177e4 | 759 | */ |
81ddef77 | 760 | void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, |
52bad64d | 761 | struct delayed_work *dwork) |
1da177e4 | 762 | { |
52bad64d | 763 | while (!cancel_delayed_work(dwork)) |
1da177e4 LT |
764 | flush_workqueue(wq); |
765 | } | |
81ddef77 | 766 | EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); |
1da177e4 LT |
767 | |
768 | /** | |
72fd4a35 | 769 | * cancel_rearming_delayed_work - reliably kill off a delayed keventd work whose handler rearms the delayed work. |
52bad64d | 770 | * @dwork: the delayed work struct |
1da177e4 | 771 | */ |
52bad64d | 772 | void cancel_rearming_delayed_work(struct delayed_work *dwork) |
1da177e4 | 773 | { |
52bad64d | 774 | cancel_rearming_delayed_workqueue(keventd_wq, dwork); |
1da177e4 LT |
775 | } |
776 | EXPORT_SYMBOL(cancel_rearming_delayed_work); | |
777 | ||
1fa44eca JB |
778 | /** |
779 | * execute_in_process_context - reliably execute the routine with user context | |
780 | * @fn: the function to execute | |
1fa44eca JB |
781 | * @ew: guaranteed storage for the execute work structure (must |
782 | * be available when the work executes) | |
783 | * | |
784 | * Executes the function immediately if process context is available, | |
785 | * otherwise schedules the function for delayed execution. | |
786 | * | |
787 | * Returns: 0 - function was executed | |
788 | * 1 - function was scheduled for execution | |
789 | */ | |
65f27f38 | 790 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
791 | { |
792 | if (!in_interrupt()) { | |
65f27f38 | 793 | fn(&ew->work); |
1fa44eca JB |
794 | return 0; |
795 | } | |
796 | ||
65f27f38 | 797 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
798 | schedule_work(&ew->work); |
799 | ||
800 | return 1; | |
801 | } | |
802 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
803 | ||
1da177e4 LT |
804 | int keventd_up(void) |
805 | { | |
806 | return keventd_wq != NULL; | |
807 | } | |
808 | ||
809 | int current_is_keventd(void) | |
810 | { | |
811 | struct cpu_workqueue_struct *cwq; | |
812 | int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ | |
813 | int ret = 0; | |
814 | ||
815 | BUG_ON(!keventd_wq); | |
816 | ||
89ada679 | 817 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
818 | if (current == cwq->thread) |
819 | ret = 1; | |
820 | ||
821 | return ret; | |
822 | ||
823 | } | |
824 | ||
1da177e4 LT |
825 | /* Take the work from this (downed) CPU. */ |
826 | static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) | |
827 | { | |
89ada679 | 828 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
626ab0e6 | 829 | struct list_head list; |
1da177e4 LT |
830 | struct work_struct *work; |
831 | ||
832 | spin_lock_irq(&cwq->lock); | |
626ab0e6 | 833 | list_replace_init(&cwq->worklist, &list); |
d721304d | 834 | migrate_sequence++; |
1da177e4 LT |
835 | |
836 | while (!list_empty(&list)) { | |
837 | printk("Taking work for %s\n", wq->name); | |
838 | work = list_entry(list.next,struct work_struct,entry); | |
839 | list_del(&work->entry); | |
89ada679 | 840 | __queue_work(per_cpu_ptr(wq->cpu_wq, smp_processor_id()), work); |
1da177e4 LT |
841 | } |
842 | spin_unlock_irq(&cwq->lock); | |
843 | } | |
844 | ||
845 | /* We're holding the cpucontrol mutex here */ | |
9c7b216d | 846 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, |
1da177e4 LT |
847 | unsigned long action, |
848 | void *hcpu) | |
849 | { | |
850 | unsigned int hotcpu = (unsigned long)hcpu; | |
851 | struct workqueue_struct *wq; | |
852 | ||
853 | switch (action) { | |
854 | case CPU_UP_PREPARE: | |
9b41ea72 | 855 | mutex_lock(&workqueue_mutex); |
1da177e4 LT |
856 | /* Create a new workqueue thread for it. */ |
857 | list_for_each_entry(wq, &workqueues, list) { | |
319c2a98 | 858 | if (!create_workqueue_thread(wq, hotcpu)) { |
1da177e4 LT |
859 | printk("workqueue for %i failed\n", hotcpu); |
860 | return NOTIFY_BAD; | |
861 | } | |
862 | } | |
863 | break; | |
864 | ||
865 | case CPU_ONLINE: | |
866 | /* Kick off worker threads. */ | |
867 | list_for_each_entry(wq, &workqueues, list) { | |
89ada679 CL |
868 | struct cpu_workqueue_struct *cwq; |
869 | ||
870 | cwq = per_cpu_ptr(wq->cpu_wq, hotcpu); | |
871 | kthread_bind(cwq->thread, hotcpu); | |
872 | wake_up_process(cwq->thread); | |
1da177e4 | 873 | } |
9b41ea72 | 874 | mutex_unlock(&workqueue_mutex); |
1da177e4 LT |
875 | break; |
876 | ||
877 | case CPU_UP_CANCELED: | |
878 | list_for_each_entry(wq, &workqueues, list) { | |
fc75cdfa HC |
879 | if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread) |
880 | continue; | |
1da177e4 | 881 | /* Unbind so it can run. */ |
89ada679 | 882 | kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread, |
a4c4af7c | 883 | any_online_cpu(cpu_online_map)); |
1da177e4 LT |
884 | cleanup_workqueue_thread(wq, hotcpu); |
885 | } | |
9b41ea72 AM |
886 | mutex_unlock(&workqueue_mutex); |
887 | break; | |
888 | ||
889 | case CPU_DOWN_PREPARE: | |
890 | mutex_lock(&workqueue_mutex); | |
891 | break; | |
892 | ||
893 | case CPU_DOWN_FAILED: | |
894 | mutex_unlock(&workqueue_mutex); | |
1da177e4 LT |
895 | break; |
896 | ||
897 | case CPU_DEAD: | |
898 | list_for_each_entry(wq, &workqueues, list) | |
899 | cleanup_workqueue_thread(wq, hotcpu); | |
900 | list_for_each_entry(wq, &workqueues, list) | |
901 | take_over_work(wq, hotcpu); | |
9b41ea72 | 902 | mutex_unlock(&workqueue_mutex); |
1da177e4 LT |
903 | break; |
904 | } | |
905 | ||
906 | return NOTIFY_OK; | |
907 | } | |
1da177e4 LT |
908 | |
909 | void init_workqueues(void) | |
910 | { | |
f756d5e2 | 911 | singlethread_cpu = first_cpu(cpu_possible_map); |
1da177e4 LT |
912 | hotcpu_notifier(workqueue_cpu_callback, 0); |
913 | keventd_wq = create_workqueue("events"); | |
914 | BUG_ON(!keventd_wq); | |
915 | } | |
916 |