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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> | |
e1f8e874 | 12 | * Andrew Morton |
1da177e4 LT |
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> |
fb39125f Z |
36 | #define CREATE_TRACE_POINTS |
37 | #include <trace/events/workqueue.h> | |
1da177e4 LT |
38 | |
39 | /* | |
f756d5e2 NL |
40 | * The per-CPU workqueue (if single thread, we always use the first |
41 | * possible cpu). | |
1da177e4 LT |
42 | */ |
43 | struct cpu_workqueue_struct { | |
44 | ||
45 | spinlock_t lock; | |
46 | ||
1da177e4 LT |
47 | struct list_head worklist; |
48 | wait_queue_head_t more_work; | |
3af24433 | 49 | struct work_struct *current_work; |
1da177e4 LT |
50 | |
51 | struct workqueue_struct *wq; | |
36c8b586 | 52 | struct task_struct *thread; |
1da177e4 LT |
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 | ||
dc186ad7 TG |
70 | #ifdef CONFIG_DEBUG_OBJECTS_WORK |
71 | ||
72 | static struct debug_obj_descr work_debug_descr; | |
73 | ||
74 | /* | |
75 | * fixup_init is called when: | |
76 | * - an active object is initialized | |
77 | */ | |
78 | static int work_fixup_init(void *addr, enum debug_obj_state state) | |
79 | { | |
80 | struct work_struct *work = addr; | |
81 | ||
82 | switch (state) { | |
83 | case ODEBUG_STATE_ACTIVE: | |
84 | cancel_work_sync(work); | |
85 | debug_object_init(work, &work_debug_descr); | |
86 | return 1; | |
87 | default: | |
88 | return 0; | |
89 | } | |
90 | } | |
91 | ||
92 | /* | |
93 | * fixup_activate is called when: | |
94 | * - an active object is activated | |
95 | * - an unknown object is activated (might be a statically initialized object) | |
96 | */ | |
97 | static int work_fixup_activate(void *addr, enum debug_obj_state state) | |
98 | { | |
99 | struct work_struct *work = addr; | |
100 | ||
101 | switch (state) { | |
102 | ||
103 | case ODEBUG_STATE_NOTAVAILABLE: | |
104 | /* | |
105 | * This is not really a fixup. The work struct was | |
106 | * statically initialized. We just make sure that it | |
107 | * is tracked in the object tracker. | |
108 | */ | |
109 | if (test_bit(WORK_STRUCT_STATIC, work_data_bits(work))) { | |
110 | debug_object_init(work, &work_debug_descr); | |
111 | debug_object_activate(work, &work_debug_descr); | |
112 | return 0; | |
113 | } | |
114 | WARN_ON_ONCE(1); | |
115 | return 0; | |
116 | ||
117 | case ODEBUG_STATE_ACTIVE: | |
118 | WARN_ON(1); | |
119 | ||
120 | default: | |
121 | return 0; | |
122 | } | |
123 | } | |
124 | ||
125 | /* | |
126 | * fixup_free is called when: | |
127 | * - an active object is freed | |
128 | */ | |
129 | static int work_fixup_free(void *addr, enum debug_obj_state state) | |
130 | { | |
131 | struct work_struct *work = addr; | |
132 | ||
133 | switch (state) { | |
134 | case ODEBUG_STATE_ACTIVE: | |
135 | cancel_work_sync(work); | |
136 | debug_object_free(work, &work_debug_descr); | |
137 | return 1; | |
138 | default: | |
139 | return 0; | |
140 | } | |
141 | } | |
142 | ||
143 | static struct debug_obj_descr work_debug_descr = { | |
144 | .name = "work_struct", | |
145 | .fixup_init = work_fixup_init, | |
146 | .fixup_activate = work_fixup_activate, | |
147 | .fixup_free = work_fixup_free, | |
148 | }; | |
149 | ||
150 | static inline void debug_work_activate(struct work_struct *work) | |
151 | { | |
152 | debug_object_activate(work, &work_debug_descr); | |
153 | } | |
154 | ||
155 | static inline void debug_work_deactivate(struct work_struct *work) | |
156 | { | |
157 | debug_object_deactivate(work, &work_debug_descr); | |
158 | } | |
159 | ||
160 | void __init_work(struct work_struct *work, int onstack) | |
161 | { | |
162 | if (onstack) | |
163 | debug_object_init_on_stack(work, &work_debug_descr); | |
164 | else | |
165 | debug_object_init(work, &work_debug_descr); | |
166 | } | |
167 | EXPORT_SYMBOL_GPL(__init_work); | |
168 | ||
169 | void destroy_work_on_stack(struct work_struct *work) | |
170 | { | |
171 | debug_object_free(work, &work_debug_descr); | |
172 | } | |
173 | EXPORT_SYMBOL_GPL(destroy_work_on_stack); | |
174 | ||
175 | #else | |
176 | static inline void debug_work_activate(struct work_struct *work) { } | |
177 | static inline void debug_work_deactivate(struct work_struct *work) { } | |
178 | #endif | |
179 | ||
95402b38 GS |
180 | /* Serializes the accesses to the list of workqueues. */ |
181 | static DEFINE_SPINLOCK(workqueue_lock); | |
1da177e4 LT |
182 | static LIST_HEAD(workqueues); |
183 | ||
3af24433 | 184 | static int singlethread_cpu __read_mostly; |
e7577c50 | 185 | static const struct cpumask *cpu_singlethread_map __read_mostly; |
14441960 ON |
186 | /* |
187 | * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD | |
188 | * flushes cwq->worklist. This means that flush_workqueue/wait_on_work | |
189 | * which comes in between can't use for_each_online_cpu(). We could | |
190 | * use cpu_possible_map, the cpumask below is more a documentation | |
191 | * than optimization. | |
192 | */ | |
e7577c50 | 193 | static cpumask_var_t cpu_populated_map __read_mostly; |
f756d5e2 | 194 | |
1da177e4 | 195 | /* If it's single threaded, it isn't in the list of workqueues. */ |
6cc88bc4 | 196 | static inline int is_wq_single_threaded(struct workqueue_struct *wq) |
1da177e4 | 197 | { |
cce1a165 | 198 | return wq->singlethread; |
1da177e4 LT |
199 | } |
200 | ||
e7577c50 | 201 | static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq) |
b1f4ec17 | 202 | { |
6cc88bc4 | 203 | return is_wq_single_threaded(wq) |
e7577c50 | 204 | ? cpu_singlethread_map : cpu_populated_map; |
b1f4ec17 ON |
205 | } |
206 | ||
a848e3b6 ON |
207 | static |
208 | struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu) | |
209 | { | |
6cc88bc4 | 210 | if (unlikely(is_wq_single_threaded(wq))) |
a848e3b6 ON |
211 | cpu = singlethread_cpu; |
212 | return per_cpu_ptr(wq->cpu_wq, cpu); | |
213 | } | |
214 | ||
4594bf15 DH |
215 | /* |
216 | * Set the workqueue on which a work item is to be run | |
217 | * - Must *only* be called if the pending flag is set | |
218 | */ | |
ed7c0fee ON |
219 | static inline void set_wq_data(struct work_struct *work, |
220 | struct cpu_workqueue_struct *cwq) | |
365970a1 | 221 | { |
4594bf15 DH |
222 | unsigned long new; |
223 | ||
224 | BUG_ON(!work_pending(work)); | |
365970a1 | 225 | |
ed7c0fee | 226 | new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING); |
a08727ba LT |
227 | new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); |
228 | atomic_long_set(&work->data, new); | |
365970a1 DH |
229 | } |
230 | ||
4d707b9f ON |
231 | /* |
232 | * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued. | |
233 | */ | |
234 | static inline void clear_wq_data(struct work_struct *work) | |
235 | { | |
236 | unsigned long flags = *work_data_bits(work) & | |
237 | (1UL << WORK_STRUCT_STATIC); | |
238 | atomic_long_set(&work->data, flags); | |
239 | } | |
240 | ||
ed7c0fee ON |
241 | static inline |
242 | struct cpu_workqueue_struct *get_wq_data(struct work_struct *work) | |
365970a1 | 243 | { |
a08727ba | 244 | return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); |
365970a1 DH |
245 | } |
246 | ||
b89deed3 | 247 | static void insert_work(struct cpu_workqueue_struct *cwq, |
1a4d9b0a | 248 | struct work_struct *work, struct list_head *head) |
b89deed3 | 249 | { |
e1d8aa9f FW |
250 | trace_workqueue_insertion(cwq->thread, work); |
251 | ||
b89deed3 | 252 | set_wq_data(work, cwq); |
6e84d644 ON |
253 | /* |
254 | * Ensure that we get the right work->data if we see the | |
255 | * result of list_add() below, see try_to_grab_pending(). | |
256 | */ | |
257 | smp_wmb(); | |
1a4d9b0a | 258 | list_add_tail(&work->entry, head); |
b89deed3 ON |
259 | wake_up(&cwq->more_work); |
260 | } | |
261 | ||
1da177e4 LT |
262 | static void __queue_work(struct cpu_workqueue_struct *cwq, |
263 | struct work_struct *work) | |
264 | { | |
265 | unsigned long flags; | |
266 | ||
dc186ad7 | 267 | debug_work_activate(work); |
1da177e4 | 268 | spin_lock_irqsave(&cwq->lock, flags); |
1a4d9b0a | 269 | insert_work(cwq, work, &cwq->worklist); |
1da177e4 LT |
270 | spin_unlock_irqrestore(&cwq->lock, flags); |
271 | } | |
272 | ||
0fcb78c2 REB |
273 | /** |
274 | * queue_work - queue work on a workqueue | |
275 | * @wq: workqueue to use | |
276 | * @work: work to queue | |
277 | * | |
057647fc | 278 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 | 279 | * |
00dfcaf7 ON |
280 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
281 | * it can be processed by another CPU. | |
1da177e4 | 282 | */ |
7ad5b3a5 | 283 | int queue_work(struct workqueue_struct *wq, struct work_struct *work) |
1da177e4 | 284 | { |
ef1ca236 ON |
285 | int ret; |
286 | ||
287 | ret = queue_work_on(get_cpu(), wq, work); | |
288 | put_cpu(); | |
289 | ||
1da177e4 LT |
290 | return ret; |
291 | } | |
ae90dd5d | 292 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 293 | |
c1a220e7 ZR |
294 | /** |
295 | * queue_work_on - queue work on specific cpu | |
296 | * @cpu: CPU number to execute work on | |
297 | * @wq: workqueue to use | |
298 | * @work: work to queue | |
299 | * | |
300 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
301 | * | |
302 | * We queue the work to a specific CPU, the caller must ensure it | |
303 | * can't go away. | |
304 | */ | |
305 | int | |
306 | queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) | |
307 | { | |
308 | int ret = 0; | |
309 | ||
310 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | |
311 | BUG_ON(!list_empty(&work->entry)); | |
312 | __queue_work(wq_per_cpu(wq, cpu), work); | |
313 | ret = 1; | |
314 | } | |
315 | return ret; | |
316 | } | |
317 | EXPORT_SYMBOL_GPL(queue_work_on); | |
318 | ||
6d141c3f | 319 | static void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 320 | { |
52bad64d | 321 | struct delayed_work *dwork = (struct delayed_work *)__data; |
ed7c0fee ON |
322 | struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
323 | struct workqueue_struct *wq = cwq->wq; | |
1da177e4 | 324 | |
a848e3b6 | 325 | __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work); |
1da177e4 LT |
326 | } |
327 | ||
0fcb78c2 REB |
328 | /** |
329 | * queue_delayed_work - queue work on a workqueue after delay | |
330 | * @wq: workqueue to use | |
af9997e4 | 331 | * @dwork: delayable work to queue |
0fcb78c2 REB |
332 | * @delay: number of jiffies to wait before queueing |
333 | * | |
057647fc | 334 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 335 | */ |
7ad5b3a5 | 336 | int queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 337 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 338 | { |
52bad64d | 339 | if (delay == 0) |
63bc0362 | 340 | return queue_work(wq, &dwork->work); |
1da177e4 | 341 | |
63bc0362 | 342 | return queue_delayed_work_on(-1, wq, dwork, delay); |
1da177e4 | 343 | } |
ae90dd5d | 344 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 345 | |
0fcb78c2 REB |
346 | /** |
347 | * queue_delayed_work_on - queue work on specific CPU after delay | |
348 | * @cpu: CPU number to execute work on | |
349 | * @wq: workqueue to use | |
af9997e4 | 350 | * @dwork: work to queue |
0fcb78c2 REB |
351 | * @delay: number of jiffies to wait before queueing |
352 | * | |
057647fc | 353 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 354 | */ |
7a6bc1cd | 355 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 356 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
357 | { |
358 | int ret = 0; | |
52bad64d DH |
359 | struct timer_list *timer = &dwork->timer; |
360 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 361 | |
a08727ba | 362 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
7a6bc1cd VP |
363 | BUG_ON(timer_pending(timer)); |
364 | BUG_ON(!list_empty(&work->entry)); | |
365 | ||
8a3e77cc AL |
366 | timer_stats_timer_set_start_info(&dwork->timer); |
367 | ||
ed7c0fee | 368 | /* This stores cwq for the moment, for the timer_fn */ |
a848e3b6 | 369 | set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id())); |
7a6bc1cd | 370 | timer->expires = jiffies + delay; |
52bad64d | 371 | timer->data = (unsigned long)dwork; |
7a6bc1cd | 372 | timer->function = delayed_work_timer_fn; |
63bc0362 ON |
373 | |
374 | if (unlikely(cpu >= 0)) | |
375 | add_timer_on(timer, cpu); | |
376 | else | |
377 | add_timer(timer); | |
7a6bc1cd VP |
378 | ret = 1; |
379 | } | |
380 | return ret; | |
381 | } | |
ae90dd5d | 382 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 383 | |
858119e1 | 384 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 385 | { |
f293ea92 | 386 | spin_lock_irq(&cwq->lock); |
1da177e4 LT |
387 | while (!list_empty(&cwq->worklist)) { |
388 | struct work_struct *work = list_entry(cwq->worklist.next, | |
389 | struct work_struct, entry); | |
6bb49e59 | 390 | work_func_t f = work->func; |
4e6045f1 JB |
391 | #ifdef CONFIG_LOCKDEP |
392 | /* | |
393 | * It is permissible to free the struct work_struct | |
394 | * from inside the function that is called from it, | |
395 | * this we need to take into account for lockdep too. | |
396 | * To avoid bogus "held lock freed" warnings as well | |
397 | * as problems when looking into work->lockdep_map, | |
398 | * make a copy and use that here. | |
399 | */ | |
400 | struct lockdep_map lockdep_map = work->lockdep_map; | |
401 | #endif | |
e1d8aa9f | 402 | trace_workqueue_execution(cwq->thread, work); |
dc186ad7 | 403 | debug_work_deactivate(work); |
b89deed3 | 404 | cwq->current_work = work; |
1da177e4 | 405 | list_del_init(cwq->worklist.next); |
f293ea92 | 406 | spin_unlock_irq(&cwq->lock); |
1da177e4 | 407 | |
365970a1 | 408 | BUG_ON(get_wq_data(work) != cwq); |
23b2e599 | 409 | work_clear_pending(work); |
3295f0ef IM |
410 | lock_map_acquire(&cwq->wq->lockdep_map); |
411 | lock_map_acquire(&lockdep_map); | |
65f27f38 | 412 | f(work); |
3295f0ef IM |
413 | lock_map_release(&lockdep_map); |
414 | lock_map_release(&cwq->wq->lockdep_map); | |
1da177e4 | 415 | |
d5abe669 PZ |
416 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
417 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
418 | "%s/0x%08x/%d\n", | |
419 | current->comm, preempt_count(), | |
ba25f9dc | 420 | task_pid_nr(current)); |
d5abe669 PZ |
421 | printk(KERN_ERR " last function: "); |
422 | print_symbol("%s\n", (unsigned long)f); | |
423 | debug_show_held_locks(current); | |
424 | dump_stack(); | |
425 | } | |
426 | ||
f293ea92 | 427 | spin_lock_irq(&cwq->lock); |
b89deed3 | 428 | cwq->current_work = NULL; |
1da177e4 | 429 | } |
f293ea92 | 430 | spin_unlock_irq(&cwq->lock); |
1da177e4 LT |
431 | } |
432 | ||
433 | static int worker_thread(void *__cwq) | |
434 | { | |
435 | struct cpu_workqueue_struct *cwq = __cwq; | |
3af24433 | 436 | DEFINE_WAIT(wait); |
1da177e4 | 437 | |
83144186 RW |
438 | if (cwq->wq->freezeable) |
439 | set_freezable(); | |
1da177e4 | 440 | |
3af24433 | 441 | for (;;) { |
3af24433 | 442 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
14441960 ON |
443 | if (!freezing(current) && |
444 | !kthread_should_stop() && | |
445 | list_empty(&cwq->worklist)) | |
1da177e4 | 446 | schedule(); |
3af24433 ON |
447 | finish_wait(&cwq->more_work, &wait); |
448 | ||
85f4186a ON |
449 | try_to_freeze(); |
450 | ||
14441960 | 451 | if (kthread_should_stop()) |
3af24433 | 452 | break; |
1da177e4 | 453 | |
3af24433 | 454 | run_workqueue(cwq); |
1da177e4 | 455 | } |
3af24433 | 456 | |
1da177e4 LT |
457 | return 0; |
458 | } | |
459 | ||
fc2e4d70 ON |
460 | struct wq_barrier { |
461 | struct work_struct work; | |
462 | struct completion done; | |
463 | }; | |
464 | ||
465 | static void wq_barrier_func(struct work_struct *work) | |
466 | { | |
467 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
468 | complete(&barr->done); | |
469 | } | |
470 | ||
83c22520 | 471 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
1a4d9b0a | 472 | struct wq_barrier *barr, struct list_head *head) |
fc2e4d70 | 473 | { |
dc186ad7 TG |
474 | /* |
475 | * debugobject calls are safe here even with cwq->lock locked | |
476 | * as we know for sure that this will not trigger any of the | |
477 | * checks and call back into the fixup functions where we | |
478 | * might deadlock. | |
479 | */ | |
480 | INIT_WORK_ON_STACK(&barr->work, wq_barrier_func); | |
fc2e4d70 ON |
481 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); |
482 | ||
483 | init_completion(&barr->done); | |
83c22520 | 484 | |
dc186ad7 | 485 | debug_work_activate(&barr->work); |
1a4d9b0a | 486 | insert_work(cwq, &barr->work, head); |
fc2e4d70 ON |
487 | } |
488 | ||
14441960 | 489 | static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 490 | { |
2355b70f LJ |
491 | int active = 0; |
492 | struct wq_barrier barr; | |
1da177e4 | 493 | |
2355b70f | 494 | WARN_ON(cwq->thread == current); |
1da177e4 | 495 | |
2355b70f LJ |
496 | spin_lock_irq(&cwq->lock); |
497 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
498 | insert_wq_barrier(cwq, &barr, &cwq->worklist); | |
499 | active = 1; | |
1da177e4 | 500 | } |
2355b70f LJ |
501 | spin_unlock_irq(&cwq->lock); |
502 | ||
dc186ad7 | 503 | if (active) { |
2355b70f | 504 | wait_for_completion(&barr.done); |
dc186ad7 TG |
505 | destroy_work_on_stack(&barr.work); |
506 | } | |
14441960 ON |
507 | |
508 | return active; | |
1da177e4 LT |
509 | } |
510 | ||
0fcb78c2 | 511 | /** |
1da177e4 | 512 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 513 | * @wq: workqueue to flush |
1da177e4 LT |
514 | * |
515 | * Forces execution of the workqueue and blocks until its completion. | |
516 | * This is typically used in driver shutdown handlers. | |
517 | * | |
fc2e4d70 ON |
518 | * We sleep until all works which were queued on entry have been handled, |
519 | * but we are not livelocked by new incoming ones. | |
1da177e4 LT |
520 | * |
521 | * This function used to run the workqueues itself. Now we just wait for the | |
522 | * helper threads to do it. | |
523 | */ | |
7ad5b3a5 | 524 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 525 | { |
e7577c50 | 526 | const struct cpumask *cpu_map = wq_cpu_map(wq); |
cce1a165 | 527 | int cpu; |
1da177e4 | 528 | |
b1f4ec17 | 529 | might_sleep(); |
3295f0ef IM |
530 | lock_map_acquire(&wq->lockdep_map); |
531 | lock_map_release(&wq->lockdep_map); | |
aa85ea5b | 532 | for_each_cpu(cpu, cpu_map) |
b1f4ec17 | 533 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
1da177e4 | 534 | } |
ae90dd5d | 535 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 536 | |
db700897 ON |
537 | /** |
538 | * flush_work - block until a work_struct's callback has terminated | |
539 | * @work: the work which is to be flushed | |
540 | * | |
a67da70d ON |
541 | * Returns false if @work has already terminated. |
542 | * | |
db700897 ON |
543 | * It is expected that, prior to calling flush_work(), the caller has |
544 | * arranged for the work to not be requeued, otherwise it doesn't make | |
545 | * sense to use this function. | |
546 | */ | |
547 | int flush_work(struct work_struct *work) | |
548 | { | |
549 | struct cpu_workqueue_struct *cwq; | |
550 | struct list_head *prev; | |
551 | struct wq_barrier barr; | |
552 | ||
553 | might_sleep(); | |
554 | cwq = get_wq_data(work); | |
555 | if (!cwq) | |
556 | return 0; | |
557 | ||
3295f0ef IM |
558 | lock_map_acquire(&cwq->wq->lockdep_map); |
559 | lock_map_release(&cwq->wq->lockdep_map); | |
a67da70d | 560 | |
db700897 ON |
561 | prev = NULL; |
562 | spin_lock_irq(&cwq->lock); | |
563 | if (!list_empty(&work->entry)) { | |
564 | /* | |
565 | * See the comment near try_to_grab_pending()->smp_rmb(). | |
566 | * If it was re-queued under us we are not going to wait. | |
567 | */ | |
568 | smp_rmb(); | |
569 | if (unlikely(cwq != get_wq_data(work))) | |
570 | goto out; | |
571 | prev = &work->entry; | |
572 | } else { | |
573 | if (cwq->current_work != work) | |
574 | goto out; | |
575 | prev = &cwq->worklist; | |
576 | } | |
577 | insert_wq_barrier(cwq, &barr, prev->next); | |
578 | out: | |
579 | spin_unlock_irq(&cwq->lock); | |
580 | if (!prev) | |
581 | return 0; | |
582 | ||
583 | wait_for_completion(&barr.done); | |
dc186ad7 | 584 | destroy_work_on_stack(&barr.work); |
db700897 ON |
585 | return 1; |
586 | } | |
587 | EXPORT_SYMBOL_GPL(flush_work); | |
588 | ||
6e84d644 | 589 | /* |
1f1f642e | 590 | * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, |
6e84d644 ON |
591 | * so this work can't be re-armed in any way. |
592 | */ | |
593 | static int try_to_grab_pending(struct work_struct *work) | |
594 | { | |
595 | struct cpu_workqueue_struct *cwq; | |
1f1f642e | 596 | int ret = -1; |
6e84d644 ON |
597 | |
598 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) | |
1f1f642e | 599 | return 0; |
6e84d644 ON |
600 | |
601 | /* | |
602 | * The queueing is in progress, or it is already queued. Try to | |
603 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
604 | */ | |
605 | ||
606 | cwq = get_wq_data(work); | |
607 | if (!cwq) | |
608 | return ret; | |
609 | ||
610 | spin_lock_irq(&cwq->lock); | |
611 | if (!list_empty(&work->entry)) { | |
612 | /* | |
613 | * This work is queued, but perhaps we locked the wrong cwq. | |
614 | * In that case we must see the new value after rmb(), see | |
615 | * insert_work()->wmb(). | |
616 | */ | |
617 | smp_rmb(); | |
618 | if (cwq == get_wq_data(work)) { | |
dc186ad7 | 619 | debug_work_deactivate(work); |
6e84d644 ON |
620 | list_del_init(&work->entry); |
621 | ret = 1; | |
622 | } | |
623 | } | |
624 | spin_unlock_irq(&cwq->lock); | |
625 | ||
626 | return ret; | |
627 | } | |
628 | ||
629 | static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | |
b89deed3 ON |
630 | struct work_struct *work) |
631 | { | |
632 | struct wq_barrier barr; | |
633 | int running = 0; | |
634 | ||
635 | spin_lock_irq(&cwq->lock); | |
636 | if (unlikely(cwq->current_work == work)) { | |
1a4d9b0a | 637 | insert_wq_barrier(cwq, &barr, cwq->worklist.next); |
b89deed3 ON |
638 | running = 1; |
639 | } | |
640 | spin_unlock_irq(&cwq->lock); | |
641 | ||
dc186ad7 | 642 | if (unlikely(running)) { |
b89deed3 | 643 | wait_for_completion(&barr.done); |
dc186ad7 TG |
644 | destroy_work_on_stack(&barr.work); |
645 | } | |
b89deed3 ON |
646 | } |
647 | ||
6e84d644 | 648 | static void wait_on_work(struct work_struct *work) |
b89deed3 ON |
649 | { |
650 | struct cpu_workqueue_struct *cwq; | |
28e53bdd | 651 | struct workqueue_struct *wq; |
e7577c50 | 652 | const struct cpumask *cpu_map; |
b1f4ec17 | 653 | int cpu; |
b89deed3 | 654 | |
f293ea92 ON |
655 | might_sleep(); |
656 | ||
3295f0ef IM |
657 | lock_map_acquire(&work->lockdep_map); |
658 | lock_map_release(&work->lockdep_map); | |
4e6045f1 | 659 | |
b89deed3 | 660 | cwq = get_wq_data(work); |
b89deed3 | 661 | if (!cwq) |
3af24433 | 662 | return; |
b89deed3 | 663 | |
28e53bdd ON |
664 | wq = cwq->wq; |
665 | cpu_map = wq_cpu_map(wq); | |
666 | ||
aa85ea5b | 667 | for_each_cpu(cpu, cpu_map) |
6e84d644 ON |
668 | wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
669 | } | |
670 | ||
1f1f642e ON |
671 | static int __cancel_work_timer(struct work_struct *work, |
672 | struct timer_list* timer) | |
673 | { | |
674 | int ret; | |
675 | ||
676 | do { | |
677 | ret = (timer && likely(del_timer(timer))); | |
678 | if (!ret) | |
679 | ret = try_to_grab_pending(work); | |
680 | wait_on_work(work); | |
681 | } while (unlikely(ret < 0)); | |
682 | ||
4d707b9f | 683 | clear_wq_data(work); |
1f1f642e ON |
684 | return ret; |
685 | } | |
686 | ||
6e84d644 ON |
687 | /** |
688 | * cancel_work_sync - block until a work_struct's callback has terminated | |
689 | * @work: the work which is to be flushed | |
690 | * | |
1f1f642e ON |
691 | * Returns true if @work was pending. |
692 | * | |
6e84d644 ON |
693 | * cancel_work_sync() will cancel the work if it is queued. If the work's |
694 | * callback appears to be running, cancel_work_sync() will block until it | |
695 | * has completed. | |
696 | * | |
697 | * It is possible to use this function if the work re-queues itself. It can | |
698 | * cancel the work even if it migrates to another workqueue, however in that | |
699 | * case it only guarantees that work->func() has completed on the last queued | |
700 | * workqueue. | |
701 | * | |
702 | * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not | |
703 | * pending, otherwise it goes into a busy-wait loop until the timer expires. | |
704 | * | |
705 | * The caller must ensure that workqueue_struct on which this work was last | |
706 | * queued can't be destroyed before this function returns. | |
707 | */ | |
1f1f642e | 708 | int cancel_work_sync(struct work_struct *work) |
6e84d644 | 709 | { |
1f1f642e | 710 | return __cancel_work_timer(work, NULL); |
b89deed3 | 711 | } |
28e53bdd | 712 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 713 | |
6e84d644 | 714 | /** |
f5a421a4 | 715 | * cancel_delayed_work_sync - reliably kill off a delayed work. |
6e84d644 ON |
716 | * @dwork: the delayed work struct |
717 | * | |
1f1f642e ON |
718 | * Returns true if @dwork was pending. |
719 | * | |
6e84d644 ON |
720 | * It is possible to use this function if @dwork rearms itself via queue_work() |
721 | * or queue_delayed_work(). See also the comment for cancel_work_sync(). | |
722 | */ | |
1f1f642e | 723 | int cancel_delayed_work_sync(struct delayed_work *dwork) |
6e84d644 | 724 | { |
1f1f642e | 725 | return __cancel_work_timer(&dwork->work, &dwork->timer); |
6e84d644 | 726 | } |
f5a421a4 | 727 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 728 | |
6e84d644 | 729 | static struct workqueue_struct *keventd_wq __read_mostly; |
1da177e4 | 730 | |
0fcb78c2 REB |
731 | /** |
732 | * schedule_work - put work task in global workqueue | |
733 | * @work: job to be done | |
734 | * | |
5b0f437d BVA |
735 | * Returns zero if @work was already on the kernel-global workqueue and |
736 | * non-zero otherwise. | |
737 | * | |
738 | * This puts a job in the kernel-global workqueue if it was not already | |
739 | * queued and leaves it in the same position on the kernel-global | |
740 | * workqueue otherwise. | |
0fcb78c2 | 741 | */ |
7ad5b3a5 | 742 | int schedule_work(struct work_struct *work) |
1da177e4 LT |
743 | { |
744 | return queue_work(keventd_wq, work); | |
745 | } | |
ae90dd5d | 746 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 747 | |
c1a220e7 ZR |
748 | /* |
749 | * schedule_work_on - put work task on a specific cpu | |
750 | * @cpu: cpu to put the work task on | |
751 | * @work: job to be done | |
752 | * | |
753 | * This puts a job on a specific cpu | |
754 | */ | |
755 | int schedule_work_on(int cpu, struct work_struct *work) | |
756 | { | |
757 | return queue_work_on(cpu, keventd_wq, work); | |
758 | } | |
759 | EXPORT_SYMBOL(schedule_work_on); | |
760 | ||
0fcb78c2 REB |
761 | /** |
762 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
763 | * @dwork: job to be done |
764 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
765 | * |
766 | * After waiting for a given time this puts a job in the kernel-global | |
767 | * workqueue. | |
768 | */ | |
7ad5b3a5 | 769 | int schedule_delayed_work(struct delayed_work *dwork, |
82f67cd9 | 770 | unsigned long delay) |
1da177e4 | 771 | { |
52bad64d | 772 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 773 | } |
ae90dd5d | 774 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 775 | |
8c53e463 LT |
776 | /** |
777 | * flush_delayed_work - block until a dwork_struct's callback has terminated | |
778 | * @dwork: the delayed work which is to be flushed | |
779 | * | |
780 | * Any timeout is cancelled, and any pending work is run immediately. | |
781 | */ | |
782 | void flush_delayed_work(struct delayed_work *dwork) | |
783 | { | |
784 | if (del_timer_sync(&dwork->timer)) { | |
785 | struct cpu_workqueue_struct *cwq; | |
47dd5be2 | 786 | cwq = wq_per_cpu(get_wq_data(&dwork->work)->wq, get_cpu()); |
8c53e463 LT |
787 | __queue_work(cwq, &dwork->work); |
788 | put_cpu(); | |
789 | } | |
790 | flush_work(&dwork->work); | |
791 | } | |
792 | EXPORT_SYMBOL(flush_delayed_work); | |
793 | ||
0fcb78c2 REB |
794 | /** |
795 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
796 | * @cpu: cpu to use | |
52bad64d | 797 | * @dwork: job to be done |
0fcb78c2 REB |
798 | * @delay: number of jiffies to wait |
799 | * | |
800 | * After waiting for a given time this puts a job in the kernel-global | |
801 | * workqueue on the specified CPU. | |
802 | */ | |
1da177e4 | 803 | int schedule_delayed_work_on(int cpu, |
52bad64d | 804 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 805 | { |
52bad64d | 806 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 807 | } |
ae90dd5d | 808 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 809 | |
b6136773 AM |
810 | /** |
811 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
812 | * @func: the function to call | |
b6136773 AM |
813 | * |
814 | * Returns zero on success. | |
815 | * Returns -ve errno on failure. | |
816 | * | |
b6136773 AM |
817 | * schedule_on_each_cpu() is very slow. |
818 | */ | |
65f27f38 | 819 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
820 | { |
821 | int cpu; | |
65a64464 | 822 | int orig = -1; |
b6136773 | 823 | struct work_struct *works; |
15316ba8 | 824 | |
b6136773 AM |
825 | works = alloc_percpu(struct work_struct); |
826 | if (!works) | |
15316ba8 | 827 | return -ENOMEM; |
b6136773 | 828 | |
93981800 TH |
829 | get_online_cpus(); |
830 | ||
65a64464 | 831 | /* |
93981800 TH |
832 | * When running in keventd don't schedule a work item on |
833 | * itself. Can just call directly because the work queue is | |
834 | * already bound. This also is faster. | |
65a64464 | 835 | */ |
93981800 | 836 | if (current_is_keventd()) |
65a64464 | 837 | orig = raw_smp_processor_id(); |
65a64464 | 838 | |
15316ba8 | 839 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
840 | struct work_struct *work = per_cpu_ptr(works, cpu); |
841 | ||
842 | INIT_WORK(work, func); | |
65a64464 | 843 | if (cpu != orig) |
93981800 | 844 | schedule_work_on(cpu, work); |
65a64464 | 845 | } |
93981800 TH |
846 | if (orig >= 0) |
847 | func(per_cpu_ptr(works, orig)); | |
848 | ||
849 | for_each_online_cpu(cpu) | |
850 | flush_work(per_cpu_ptr(works, cpu)); | |
851 | ||
95402b38 | 852 | put_online_cpus(); |
b6136773 | 853 | free_percpu(works); |
15316ba8 CL |
854 | return 0; |
855 | } | |
856 | ||
eef6a7d5 AS |
857 | /** |
858 | * flush_scheduled_work - ensure that any scheduled work has run to completion. | |
859 | * | |
860 | * Forces execution of the kernel-global workqueue and blocks until its | |
861 | * completion. | |
862 | * | |
863 | * Think twice before calling this function! It's very easy to get into | |
864 | * trouble if you don't take great care. Either of the following situations | |
865 | * will lead to deadlock: | |
866 | * | |
867 | * One of the work items currently on the workqueue needs to acquire | |
868 | * a lock held by your code or its caller. | |
869 | * | |
870 | * Your code is running in the context of a work routine. | |
871 | * | |
872 | * They will be detected by lockdep when they occur, but the first might not | |
873 | * occur very often. It depends on what work items are on the workqueue and | |
874 | * what locks they need, which you have no control over. | |
875 | * | |
876 | * In most situations flushing the entire workqueue is overkill; you merely | |
877 | * need to know that a particular work item isn't queued and isn't running. | |
878 | * In such cases you should use cancel_delayed_work_sync() or | |
879 | * cancel_work_sync() instead. | |
880 | */ | |
1da177e4 LT |
881 | void flush_scheduled_work(void) |
882 | { | |
883 | flush_workqueue(keventd_wq); | |
884 | } | |
ae90dd5d | 885 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 886 | |
1fa44eca JB |
887 | /** |
888 | * execute_in_process_context - reliably execute the routine with user context | |
889 | * @fn: the function to execute | |
1fa44eca JB |
890 | * @ew: guaranteed storage for the execute work structure (must |
891 | * be available when the work executes) | |
892 | * | |
893 | * Executes the function immediately if process context is available, | |
894 | * otherwise schedules the function for delayed execution. | |
895 | * | |
896 | * Returns: 0 - function was executed | |
897 | * 1 - function was scheduled for execution | |
898 | */ | |
65f27f38 | 899 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
900 | { |
901 | if (!in_interrupt()) { | |
65f27f38 | 902 | fn(&ew->work); |
1fa44eca JB |
903 | return 0; |
904 | } | |
905 | ||
65f27f38 | 906 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
907 | schedule_work(&ew->work); |
908 | ||
909 | return 1; | |
910 | } | |
911 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
912 | ||
1da177e4 LT |
913 | int keventd_up(void) |
914 | { | |
915 | return keventd_wq != NULL; | |
916 | } | |
917 | ||
918 | int current_is_keventd(void) | |
919 | { | |
920 | struct cpu_workqueue_struct *cwq; | |
d243769d | 921 | int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ |
1da177e4 LT |
922 | int ret = 0; |
923 | ||
924 | BUG_ON(!keventd_wq); | |
925 | ||
89ada679 | 926 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
927 | if (current == cwq->thread) |
928 | ret = 1; | |
929 | ||
930 | return ret; | |
931 | ||
932 | } | |
933 | ||
3af24433 ON |
934 | static struct cpu_workqueue_struct * |
935 | init_cpu_workqueue(struct workqueue_struct *wq, int cpu) | |
1da177e4 | 936 | { |
89ada679 | 937 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 | 938 | |
3af24433 ON |
939 | cwq->wq = wq; |
940 | spin_lock_init(&cwq->lock); | |
941 | INIT_LIST_HEAD(&cwq->worklist); | |
942 | init_waitqueue_head(&cwq->more_work); | |
943 | ||
944 | return cwq; | |
1da177e4 LT |
945 | } |
946 | ||
3af24433 ON |
947 | static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
948 | { | |
949 | struct workqueue_struct *wq = cwq->wq; | |
6cc88bc4 | 950 | const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d"; |
3af24433 ON |
951 | struct task_struct *p; |
952 | ||
953 | p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu); | |
954 | /* | |
955 | * Nobody can add the work_struct to this cwq, | |
956 | * if (caller is __create_workqueue) | |
957 | * nobody should see this wq | |
958 | * else // caller is CPU_UP_PREPARE | |
959 | * cpu is not on cpu_online_map | |
960 | * so we can abort safely. | |
961 | */ | |
962 | if (IS_ERR(p)) | |
963 | return PTR_ERR(p); | |
3af24433 | 964 | cwq->thread = p; |
3af24433 | 965 | |
e1d8aa9f FW |
966 | trace_workqueue_creation(cwq->thread, cpu); |
967 | ||
3af24433 ON |
968 | return 0; |
969 | } | |
970 | ||
06ba38a9 ON |
971 | static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
972 | { | |
973 | struct task_struct *p = cwq->thread; | |
974 | ||
975 | if (p != NULL) { | |
976 | if (cpu >= 0) | |
977 | kthread_bind(p, cpu); | |
978 | wake_up_process(p); | |
979 | } | |
980 | } | |
981 | ||
4e6045f1 JB |
982 | struct workqueue_struct *__create_workqueue_key(const char *name, |
983 | int singlethread, | |
984 | int freezeable, | |
eb13ba87 JB |
985 | struct lock_class_key *key, |
986 | const char *lock_name) | |
1da177e4 | 987 | { |
1da177e4 | 988 | struct workqueue_struct *wq; |
3af24433 ON |
989 | struct cpu_workqueue_struct *cwq; |
990 | int err = 0, cpu; | |
1da177e4 | 991 | |
3af24433 ON |
992 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
993 | if (!wq) | |
994 | return NULL; | |
995 | ||
996 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); | |
997 | if (!wq->cpu_wq) { | |
998 | kfree(wq); | |
999 | return NULL; | |
1000 | } | |
1001 | ||
1002 | wq->name = name; | |
eb13ba87 | 1003 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 1004 | wq->singlethread = singlethread; |
3af24433 | 1005 | wq->freezeable = freezeable; |
cce1a165 | 1006 | INIT_LIST_HEAD(&wq->list); |
3af24433 ON |
1007 | |
1008 | if (singlethread) { | |
3af24433 ON |
1009 | cwq = init_cpu_workqueue(wq, singlethread_cpu); |
1010 | err = create_workqueue_thread(cwq, singlethread_cpu); | |
06ba38a9 | 1011 | start_workqueue_thread(cwq, -1); |
3af24433 | 1012 | } else { |
3da1c84c | 1013 | cpu_maps_update_begin(); |
6af8bf3d ON |
1014 | /* |
1015 | * We must place this wq on list even if the code below fails. | |
1016 | * cpu_down(cpu) can remove cpu from cpu_populated_map before | |
1017 | * destroy_workqueue() takes the lock, in that case we leak | |
1018 | * cwq[cpu]->thread. | |
1019 | */ | |
95402b38 | 1020 | spin_lock(&workqueue_lock); |
3af24433 | 1021 | list_add(&wq->list, &workqueues); |
95402b38 | 1022 | spin_unlock(&workqueue_lock); |
6af8bf3d ON |
1023 | /* |
1024 | * We must initialize cwqs for each possible cpu even if we | |
1025 | * are going to call destroy_workqueue() finally. Otherwise | |
1026 | * cpu_up() can hit the uninitialized cwq once we drop the | |
1027 | * lock. | |
1028 | */ | |
3af24433 ON |
1029 | for_each_possible_cpu(cpu) { |
1030 | cwq = init_cpu_workqueue(wq, cpu); | |
1031 | if (err || !cpu_online(cpu)) | |
1032 | continue; | |
1033 | err = create_workqueue_thread(cwq, cpu); | |
06ba38a9 | 1034 | start_workqueue_thread(cwq, cpu); |
1da177e4 | 1035 | } |
3da1c84c | 1036 | cpu_maps_update_done(); |
3af24433 ON |
1037 | } |
1038 | ||
1039 | if (err) { | |
1040 | destroy_workqueue(wq); | |
1041 | wq = NULL; | |
1042 | } | |
1043 | return wq; | |
1044 | } | |
4e6045f1 | 1045 | EXPORT_SYMBOL_GPL(__create_workqueue_key); |
1da177e4 | 1046 | |
1e35eaa2 | 1047 | static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) |
3af24433 | 1048 | { |
14441960 | 1049 | /* |
3da1c84c ON |
1050 | * Our caller is either destroy_workqueue() or CPU_POST_DEAD, |
1051 | * cpu_add_remove_lock protects cwq->thread. | |
14441960 ON |
1052 | */ |
1053 | if (cwq->thread == NULL) | |
1054 | return; | |
3af24433 | 1055 | |
3295f0ef IM |
1056 | lock_map_acquire(&cwq->wq->lockdep_map); |
1057 | lock_map_release(&cwq->wq->lockdep_map); | |
4e6045f1 | 1058 | |
13c22168 | 1059 | flush_cpu_workqueue(cwq); |
14441960 | 1060 | /* |
3da1c84c | 1061 | * If the caller is CPU_POST_DEAD and cwq->worklist was not empty, |
13c22168 ON |
1062 | * a concurrent flush_workqueue() can insert a barrier after us. |
1063 | * However, in that case run_workqueue() won't return and check | |
1064 | * kthread_should_stop() until it flushes all work_struct's. | |
14441960 ON |
1065 | * When ->worklist becomes empty it is safe to exit because no |
1066 | * more work_structs can be queued on this cwq: flush_workqueue | |
1067 | * checks list_empty(), and a "normal" queue_work() can't use | |
1068 | * a dead CPU. | |
1069 | */ | |
e1d8aa9f | 1070 | trace_workqueue_destruction(cwq->thread); |
14441960 ON |
1071 | kthread_stop(cwq->thread); |
1072 | cwq->thread = NULL; | |
3af24433 ON |
1073 | } |
1074 | ||
1075 | /** | |
1076 | * destroy_workqueue - safely terminate a workqueue | |
1077 | * @wq: target workqueue | |
1078 | * | |
1079 | * Safely destroy a workqueue. All work currently pending will be done first. | |
1080 | */ | |
1081 | void destroy_workqueue(struct workqueue_struct *wq) | |
1082 | { | |
e7577c50 | 1083 | const struct cpumask *cpu_map = wq_cpu_map(wq); |
b1f4ec17 | 1084 | int cpu; |
3af24433 | 1085 | |
3da1c84c | 1086 | cpu_maps_update_begin(); |
95402b38 | 1087 | spin_lock(&workqueue_lock); |
b1f4ec17 | 1088 | list_del(&wq->list); |
95402b38 | 1089 | spin_unlock(&workqueue_lock); |
3af24433 | 1090 | |
aa85ea5b | 1091 | for_each_cpu(cpu, cpu_map) |
1e35eaa2 | 1092 | cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu)); |
3da1c84c | 1093 | cpu_maps_update_done(); |
9b41ea72 | 1094 | |
3af24433 ON |
1095 | free_percpu(wq->cpu_wq); |
1096 | kfree(wq); | |
1097 | } | |
1098 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
1099 | ||
1100 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
1101 | unsigned long action, | |
1102 | void *hcpu) | |
1103 | { | |
1104 | unsigned int cpu = (unsigned long)hcpu; | |
1105 | struct cpu_workqueue_struct *cwq; | |
1106 | struct workqueue_struct *wq; | |
80b5184c | 1107 | int err = 0; |
3af24433 | 1108 | |
8bb78442 RW |
1109 | action &= ~CPU_TASKS_FROZEN; |
1110 | ||
3af24433 | 1111 | switch (action) { |
3af24433 | 1112 | case CPU_UP_PREPARE: |
e7577c50 | 1113 | cpumask_set_cpu(cpu, cpu_populated_map); |
3af24433 | 1114 | } |
8448502c | 1115 | undo: |
3af24433 ON |
1116 | list_for_each_entry(wq, &workqueues, list) { |
1117 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
1118 | ||
1119 | switch (action) { | |
1120 | case CPU_UP_PREPARE: | |
80b5184c AM |
1121 | err = create_workqueue_thread(cwq, cpu); |
1122 | if (!err) | |
3af24433 | 1123 | break; |
95402b38 GS |
1124 | printk(KERN_ERR "workqueue [%s] for %i failed\n", |
1125 | wq->name, cpu); | |
8448502c | 1126 | action = CPU_UP_CANCELED; |
80b5184c | 1127 | err = -ENOMEM; |
8448502c | 1128 | goto undo; |
3af24433 ON |
1129 | |
1130 | case CPU_ONLINE: | |
06ba38a9 | 1131 | start_workqueue_thread(cwq, cpu); |
3af24433 ON |
1132 | break; |
1133 | ||
1134 | case CPU_UP_CANCELED: | |
06ba38a9 | 1135 | start_workqueue_thread(cwq, -1); |
3da1c84c | 1136 | case CPU_POST_DEAD: |
1e35eaa2 | 1137 | cleanup_workqueue_thread(cwq); |
3af24433 ON |
1138 | break; |
1139 | } | |
1da177e4 LT |
1140 | } |
1141 | ||
00dfcaf7 ON |
1142 | switch (action) { |
1143 | case CPU_UP_CANCELED: | |
3da1c84c | 1144 | case CPU_POST_DEAD: |
e7577c50 | 1145 | cpumask_clear_cpu(cpu, cpu_populated_map); |
00dfcaf7 ON |
1146 | } |
1147 | ||
80b5184c | 1148 | return notifier_from_errno(err); |
1da177e4 | 1149 | } |
1da177e4 | 1150 | |
2d3854a3 | 1151 | #ifdef CONFIG_SMP |
8ccad40d | 1152 | |
2d3854a3 | 1153 | struct work_for_cpu { |
6b44003e | 1154 | struct completion completion; |
2d3854a3 RR |
1155 | long (*fn)(void *); |
1156 | void *arg; | |
1157 | long ret; | |
1158 | }; | |
1159 | ||
6b44003e | 1160 | static int do_work_for_cpu(void *_wfc) |
2d3854a3 | 1161 | { |
6b44003e | 1162 | struct work_for_cpu *wfc = _wfc; |
2d3854a3 | 1163 | wfc->ret = wfc->fn(wfc->arg); |
6b44003e AM |
1164 | complete(&wfc->completion); |
1165 | return 0; | |
2d3854a3 RR |
1166 | } |
1167 | ||
1168 | /** | |
1169 | * work_on_cpu - run a function in user context on a particular cpu | |
1170 | * @cpu: the cpu to run on | |
1171 | * @fn: the function to run | |
1172 | * @arg: the function arg | |
1173 | * | |
31ad9081 RR |
1174 | * This will return the value @fn returns. |
1175 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
6b44003e | 1176 | * The caller must not hold any locks which would prevent @fn from completing. |
2d3854a3 RR |
1177 | */ |
1178 | long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) | |
1179 | { | |
6b44003e AM |
1180 | struct task_struct *sub_thread; |
1181 | struct work_for_cpu wfc = { | |
1182 | .completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion), | |
1183 | .fn = fn, | |
1184 | .arg = arg, | |
1185 | }; | |
1186 | ||
1187 | sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu"); | |
1188 | if (IS_ERR(sub_thread)) | |
1189 | return PTR_ERR(sub_thread); | |
1190 | kthread_bind(sub_thread, cpu); | |
1191 | wake_up_process(sub_thread); | |
1192 | wait_for_completion(&wfc.completion); | |
2d3854a3 RR |
1193 | return wfc.ret; |
1194 | } | |
1195 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
1196 | #endif /* CONFIG_SMP */ | |
1197 | ||
c12920d1 | 1198 | void __init init_workqueues(void) |
1da177e4 | 1199 | { |
e7577c50 RR |
1200 | alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL); |
1201 | ||
1202 | cpumask_copy(cpu_populated_map, cpu_online_mask); | |
1203 | singlethread_cpu = cpumask_first(cpu_possible_mask); | |
1204 | cpu_singlethread_map = cpumask_of(singlethread_cpu); | |
1da177e4 LT |
1205 | hotcpu_notifier(workqueue_cpu_callback, 0); |
1206 | keventd_wq = create_workqueue("events"); | |
1207 | BUG_ON(!keventd_wq); | |
1208 | } |