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 */ |
0d557dc9 | 65 | int rt; |
4e6045f1 JB |
66 | #ifdef CONFIG_LOCKDEP |
67 | struct lockdep_map lockdep_map; | |
68 | #endif | |
1da177e4 LT |
69 | }; |
70 | ||
dc186ad7 TG |
71 | #ifdef CONFIG_DEBUG_OBJECTS_WORK |
72 | ||
73 | static struct debug_obj_descr work_debug_descr; | |
74 | ||
75 | /* | |
76 | * fixup_init is called when: | |
77 | * - an active object is initialized | |
78 | */ | |
79 | static int work_fixup_init(void *addr, enum debug_obj_state state) | |
80 | { | |
81 | struct work_struct *work = addr; | |
82 | ||
83 | switch (state) { | |
84 | case ODEBUG_STATE_ACTIVE: | |
85 | cancel_work_sync(work); | |
86 | debug_object_init(work, &work_debug_descr); | |
87 | return 1; | |
88 | default: | |
89 | return 0; | |
90 | } | |
91 | } | |
92 | ||
93 | /* | |
94 | * fixup_activate is called when: | |
95 | * - an active object is activated | |
96 | * - an unknown object is activated (might be a statically initialized object) | |
97 | */ | |
98 | static int work_fixup_activate(void *addr, enum debug_obj_state state) | |
99 | { | |
100 | struct work_struct *work = addr; | |
101 | ||
102 | switch (state) { | |
103 | ||
104 | case ODEBUG_STATE_NOTAVAILABLE: | |
105 | /* | |
106 | * This is not really a fixup. The work struct was | |
107 | * statically initialized. We just make sure that it | |
108 | * is tracked in the object tracker. | |
109 | */ | |
110 | if (test_bit(WORK_STRUCT_STATIC, work_data_bits(work))) { | |
111 | debug_object_init(work, &work_debug_descr); | |
112 | debug_object_activate(work, &work_debug_descr); | |
113 | return 0; | |
114 | } | |
115 | WARN_ON_ONCE(1); | |
116 | return 0; | |
117 | ||
118 | case ODEBUG_STATE_ACTIVE: | |
119 | WARN_ON(1); | |
120 | ||
121 | default: | |
122 | return 0; | |
123 | } | |
124 | } | |
125 | ||
126 | /* | |
127 | * fixup_free is called when: | |
128 | * - an active object is freed | |
129 | */ | |
130 | static int work_fixup_free(void *addr, enum debug_obj_state state) | |
131 | { | |
132 | struct work_struct *work = addr; | |
133 | ||
134 | switch (state) { | |
135 | case ODEBUG_STATE_ACTIVE: | |
136 | cancel_work_sync(work); | |
137 | debug_object_free(work, &work_debug_descr); | |
138 | return 1; | |
139 | default: | |
140 | return 0; | |
141 | } | |
142 | } | |
143 | ||
144 | static struct debug_obj_descr work_debug_descr = { | |
145 | .name = "work_struct", | |
146 | .fixup_init = work_fixup_init, | |
147 | .fixup_activate = work_fixup_activate, | |
148 | .fixup_free = work_fixup_free, | |
149 | }; | |
150 | ||
151 | static inline void debug_work_activate(struct work_struct *work) | |
152 | { | |
153 | debug_object_activate(work, &work_debug_descr); | |
154 | } | |
155 | ||
156 | static inline void debug_work_deactivate(struct work_struct *work) | |
157 | { | |
158 | debug_object_deactivate(work, &work_debug_descr); | |
159 | } | |
160 | ||
161 | void __init_work(struct work_struct *work, int onstack) | |
162 | { | |
163 | if (onstack) | |
164 | debug_object_init_on_stack(work, &work_debug_descr); | |
165 | else | |
166 | debug_object_init(work, &work_debug_descr); | |
167 | } | |
168 | EXPORT_SYMBOL_GPL(__init_work); | |
169 | ||
170 | void destroy_work_on_stack(struct work_struct *work) | |
171 | { | |
172 | debug_object_free(work, &work_debug_descr); | |
173 | } | |
174 | EXPORT_SYMBOL_GPL(destroy_work_on_stack); | |
175 | ||
176 | #else | |
177 | static inline void debug_work_activate(struct work_struct *work) { } | |
178 | static inline void debug_work_deactivate(struct work_struct *work) { } | |
179 | #endif | |
180 | ||
95402b38 GS |
181 | /* Serializes the accesses to the list of workqueues. */ |
182 | static DEFINE_SPINLOCK(workqueue_lock); | |
1da177e4 LT |
183 | static LIST_HEAD(workqueues); |
184 | ||
3af24433 | 185 | static int singlethread_cpu __read_mostly; |
e7577c50 | 186 | static const struct cpumask *cpu_singlethread_map __read_mostly; |
14441960 ON |
187 | /* |
188 | * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD | |
189 | * flushes cwq->worklist. This means that flush_workqueue/wait_on_work | |
190 | * which comes in between can't use for_each_online_cpu(). We could | |
191 | * use cpu_possible_map, the cpumask below is more a documentation | |
192 | * than optimization. | |
193 | */ | |
e7577c50 | 194 | static cpumask_var_t cpu_populated_map __read_mostly; |
f756d5e2 | 195 | |
1da177e4 | 196 | /* If it's single threaded, it isn't in the list of workqueues. */ |
6cc88bc4 | 197 | static inline int is_wq_single_threaded(struct workqueue_struct *wq) |
1da177e4 | 198 | { |
cce1a165 | 199 | return wq->singlethread; |
1da177e4 LT |
200 | } |
201 | ||
e7577c50 | 202 | static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq) |
b1f4ec17 | 203 | { |
6cc88bc4 | 204 | return is_wq_single_threaded(wq) |
e7577c50 | 205 | ? cpu_singlethread_map : cpu_populated_map; |
b1f4ec17 ON |
206 | } |
207 | ||
a848e3b6 ON |
208 | static |
209 | struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu) | |
210 | { | |
6cc88bc4 | 211 | if (unlikely(is_wq_single_threaded(wq))) |
a848e3b6 ON |
212 | cpu = singlethread_cpu; |
213 | return per_cpu_ptr(wq->cpu_wq, cpu); | |
214 | } | |
215 | ||
4594bf15 DH |
216 | /* |
217 | * Set the workqueue on which a work item is to be run | |
218 | * - Must *only* be called if the pending flag is set | |
219 | */ | |
ed7c0fee ON |
220 | static inline void set_wq_data(struct work_struct *work, |
221 | struct cpu_workqueue_struct *cwq) | |
365970a1 | 222 | { |
4594bf15 DH |
223 | unsigned long new; |
224 | ||
225 | BUG_ON(!work_pending(work)); | |
365970a1 | 226 | |
ed7c0fee | 227 | new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING); |
a08727ba LT |
228 | new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); |
229 | atomic_long_set(&work->data, new); | |
365970a1 DH |
230 | } |
231 | ||
4d707b9f ON |
232 | /* |
233 | * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued. | |
234 | */ | |
235 | static inline void clear_wq_data(struct work_struct *work) | |
236 | { | |
237 | unsigned long flags = *work_data_bits(work) & | |
238 | (1UL << WORK_STRUCT_STATIC); | |
239 | atomic_long_set(&work->data, flags); | |
240 | } | |
241 | ||
ed7c0fee ON |
242 | static inline |
243 | struct cpu_workqueue_struct *get_wq_data(struct work_struct *work) | |
365970a1 | 244 | { |
a08727ba | 245 | return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); |
365970a1 DH |
246 | } |
247 | ||
b89deed3 | 248 | static void insert_work(struct cpu_workqueue_struct *cwq, |
1a4d9b0a | 249 | struct work_struct *work, struct list_head *head) |
b89deed3 | 250 | { |
e1d8aa9f FW |
251 | trace_workqueue_insertion(cwq->thread, work); |
252 | ||
b89deed3 | 253 | set_wq_data(work, cwq); |
6e84d644 ON |
254 | /* |
255 | * Ensure that we get the right work->data if we see the | |
256 | * result of list_add() below, see try_to_grab_pending(). | |
257 | */ | |
258 | smp_wmb(); | |
1a4d9b0a | 259 | list_add_tail(&work->entry, head); |
b89deed3 ON |
260 | wake_up(&cwq->more_work); |
261 | } | |
262 | ||
1da177e4 LT |
263 | static void __queue_work(struct cpu_workqueue_struct *cwq, |
264 | struct work_struct *work) | |
265 | { | |
266 | unsigned long flags; | |
267 | ||
dc186ad7 | 268 | debug_work_activate(work); |
1da177e4 | 269 | spin_lock_irqsave(&cwq->lock, flags); |
1a4d9b0a | 270 | insert_work(cwq, work, &cwq->worklist); |
1da177e4 LT |
271 | spin_unlock_irqrestore(&cwq->lock, flags); |
272 | } | |
273 | ||
0fcb78c2 REB |
274 | /** |
275 | * queue_work - queue work on a workqueue | |
276 | * @wq: workqueue to use | |
277 | * @work: work to queue | |
278 | * | |
057647fc | 279 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 | 280 | * |
00dfcaf7 ON |
281 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
282 | * it can be processed by another CPU. | |
1da177e4 | 283 | */ |
7ad5b3a5 | 284 | int queue_work(struct workqueue_struct *wq, struct work_struct *work) |
1da177e4 | 285 | { |
ef1ca236 ON |
286 | int ret; |
287 | ||
288 | ret = queue_work_on(get_cpu(), wq, work); | |
289 | put_cpu(); | |
290 | ||
1da177e4 LT |
291 | return ret; |
292 | } | |
ae90dd5d | 293 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 294 | |
c1a220e7 ZR |
295 | /** |
296 | * queue_work_on - queue work on specific cpu | |
297 | * @cpu: CPU number to execute work on | |
298 | * @wq: workqueue to use | |
299 | * @work: work to queue | |
300 | * | |
301 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
302 | * | |
303 | * We queue the work to a specific CPU, the caller must ensure it | |
304 | * can't go away. | |
305 | */ | |
306 | int | |
307 | queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) | |
308 | { | |
309 | int ret = 0; | |
310 | ||
311 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | |
312 | BUG_ON(!list_empty(&work->entry)); | |
313 | __queue_work(wq_per_cpu(wq, cpu), work); | |
314 | ret = 1; | |
315 | } | |
316 | return ret; | |
317 | } | |
318 | EXPORT_SYMBOL_GPL(queue_work_on); | |
319 | ||
6d141c3f | 320 | static void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 321 | { |
52bad64d | 322 | struct delayed_work *dwork = (struct delayed_work *)__data; |
ed7c0fee ON |
323 | struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
324 | struct workqueue_struct *wq = cwq->wq; | |
1da177e4 | 325 | |
a848e3b6 | 326 | __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work); |
1da177e4 LT |
327 | } |
328 | ||
0fcb78c2 REB |
329 | /** |
330 | * queue_delayed_work - queue work on a workqueue after delay | |
331 | * @wq: workqueue to use | |
af9997e4 | 332 | * @dwork: delayable work to queue |
0fcb78c2 REB |
333 | * @delay: number of jiffies to wait before queueing |
334 | * | |
057647fc | 335 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 336 | */ |
7ad5b3a5 | 337 | int queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 338 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 339 | { |
52bad64d | 340 | if (delay == 0) |
63bc0362 | 341 | return queue_work(wq, &dwork->work); |
1da177e4 | 342 | |
63bc0362 | 343 | return queue_delayed_work_on(-1, wq, dwork, delay); |
1da177e4 | 344 | } |
ae90dd5d | 345 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 346 | |
0fcb78c2 REB |
347 | /** |
348 | * queue_delayed_work_on - queue work on specific CPU after delay | |
349 | * @cpu: CPU number to execute work on | |
350 | * @wq: workqueue to use | |
af9997e4 | 351 | * @dwork: work to queue |
0fcb78c2 REB |
352 | * @delay: number of jiffies to wait before queueing |
353 | * | |
057647fc | 354 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 355 | */ |
7a6bc1cd | 356 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 357 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
358 | { |
359 | int ret = 0; | |
52bad64d DH |
360 | struct timer_list *timer = &dwork->timer; |
361 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 362 | |
a08727ba | 363 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
7a6bc1cd VP |
364 | BUG_ON(timer_pending(timer)); |
365 | BUG_ON(!list_empty(&work->entry)); | |
366 | ||
8a3e77cc AL |
367 | timer_stats_timer_set_start_info(&dwork->timer); |
368 | ||
ed7c0fee | 369 | /* This stores cwq for the moment, for the timer_fn */ |
a848e3b6 | 370 | set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id())); |
7a6bc1cd | 371 | timer->expires = jiffies + delay; |
52bad64d | 372 | timer->data = (unsigned long)dwork; |
7a6bc1cd | 373 | timer->function = delayed_work_timer_fn; |
63bc0362 ON |
374 | |
375 | if (unlikely(cpu >= 0)) | |
376 | add_timer_on(timer, cpu); | |
377 | else | |
378 | add_timer(timer); | |
7a6bc1cd VP |
379 | ret = 1; |
380 | } | |
381 | return ret; | |
382 | } | |
ae90dd5d | 383 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 384 | |
858119e1 | 385 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 386 | { |
f293ea92 | 387 | spin_lock_irq(&cwq->lock); |
1da177e4 LT |
388 | while (!list_empty(&cwq->worklist)) { |
389 | struct work_struct *work = list_entry(cwq->worklist.next, | |
390 | struct work_struct, entry); | |
6bb49e59 | 391 | work_func_t f = work->func; |
4e6045f1 JB |
392 | #ifdef CONFIG_LOCKDEP |
393 | /* | |
394 | * It is permissible to free the struct work_struct | |
395 | * from inside the function that is called from it, | |
396 | * this we need to take into account for lockdep too. | |
397 | * To avoid bogus "held lock freed" warnings as well | |
398 | * as problems when looking into work->lockdep_map, | |
399 | * make a copy and use that here. | |
400 | */ | |
401 | struct lockdep_map lockdep_map = work->lockdep_map; | |
402 | #endif | |
e1d8aa9f | 403 | trace_workqueue_execution(cwq->thread, work); |
dc186ad7 | 404 | debug_work_deactivate(work); |
b89deed3 | 405 | cwq->current_work = work; |
1da177e4 | 406 | list_del_init(cwq->worklist.next); |
f293ea92 | 407 | spin_unlock_irq(&cwq->lock); |
1da177e4 | 408 | |
365970a1 | 409 | BUG_ON(get_wq_data(work) != cwq); |
23b2e599 | 410 | work_clear_pending(work); |
3295f0ef IM |
411 | lock_map_acquire(&cwq->wq->lockdep_map); |
412 | lock_map_acquire(&lockdep_map); | |
65f27f38 | 413 | f(work); |
3295f0ef IM |
414 | lock_map_release(&lockdep_map); |
415 | lock_map_release(&cwq->wq->lockdep_map); | |
1da177e4 | 416 | |
d5abe669 PZ |
417 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
418 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
419 | "%s/0x%08x/%d\n", | |
420 | current->comm, preempt_count(), | |
ba25f9dc | 421 | task_pid_nr(current)); |
d5abe669 PZ |
422 | printk(KERN_ERR " last function: "); |
423 | print_symbol("%s\n", (unsigned long)f); | |
424 | debug_show_held_locks(current); | |
425 | dump_stack(); | |
426 | } | |
427 | ||
f293ea92 | 428 | spin_lock_irq(&cwq->lock); |
b89deed3 | 429 | cwq->current_work = NULL; |
1da177e4 | 430 | } |
f293ea92 | 431 | spin_unlock_irq(&cwq->lock); |
1da177e4 LT |
432 | } |
433 | ||
434 | static int worker_thread(void *__cwq) | |
435 | { | |
436 | struct cpu_workqueue_struct *cwq = __cwq; | |
3af24433 | 437 | DEFINE_WAIT(wait); |
1da177e4 | 438 | |
83144186 RW |
439 | if (cwq->wq->freezeable) |
440 | set_freezable(); | |
1da177e4 | 441 | |
3af24433 | 442 | for (;;) { |
3af24433 | 443 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
14441960 ON |
444 | if (!freezing(current) && |
445 | !kthread_should_stop() && | |
446 | list_empty(&cwq->worklist)) | |
1da177e4 | 447 | schedule(); |
3af24433 ON |
448 | finish_wait(&cwq->more_work, &wait); |
449 | ||
85f4186a ON |
450 | try_to_freeze(); |
451 | ||
14441960 | 452 | if (kthread_should_stop()) |
3af24433 | 453 | break; |
1da177e4 | 454 | |
3af24433 | 455 | run_workqueue(cwq); |
1da177e4 | 456 | } |
3af24433 | 457 | |
1da177e4 LT |
458 | return 0; |
459 | } | |
460 | ||
fc2e4d70 ON |
461 | struct wq_barrier { |
462 | struct work_struct work; | |
463 | struct completion done; | |
464 | }; | |
465 | ||
466 | static void wq_barrier_func(struct work_struct *work) | |
467 | { | |
468 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
469 | complete(&barr->done); | |
470 | } | |
471 | ||
83c22520 | 472 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
1a4d9b0a | 473 | struct wq_barrier *barr, struct list_head *head) |
fc2e4d70 | 474 | { |
dc186ad7 TG |
475 | /* |
476 | * debugobject calls are safe here even with cwq->lock locked | |
477 | * as we know for sure that this will not trigger any of the | |
478 | * checks and call back into the fixup functions where we | |
479 | * might deadlock. | |
480 | */ | |
481 | INIT_WORK_ON_STACK(&barr->work, wq_barrier_func); | |
fc2e4d70 ON |
482 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); |
483 | ||
484 | init_completion(&barr->done); | |
83c22520 | 485 | |
dc186ad7 | 486 | debug_work_activate(&barr->work); |
1a4d9b0a | 487 | insert_work(cwq, &barr->work, head); |
fc2e4d70 ON |
488 | } |
489 | ||
14441960 | 490 | static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 491 | { |
2355b70f LJ |
492 | int active = 0; |
493 | struct wq_barrier barr; | |
1da177e4 | 494 | |
2355b70f | 495 | WARN_ON(cwq->thread == current); |
1da177e4 | 496 | |
2355b70f LJ |
497 | spin_lock_irq(&cwq->lock); |
498 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
499 | insert_wq_barrier(cwq, &barr, &cwq->worklist); | |
500 | active = 1; | |
1da177e4 | 501 | } |
2355b70f LJ |
502 | spin_unlock_irq(&cwq->lock); |
503 | ||
dc186ad7 | 504 | if (active) { |
2355b70f | 505 | wait_for_completion(&barr.done); |
dc186ad7 TG |
506 | destroy_work_on_stack(&barr.work); |
507 | } | |
14441960 ON |
508 | |
509 | return active; | |
1da177e4 LT |
510 | } |
511 | ||
0fcb78c2 | 512 | /** |
1da177e4 | 513 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 514 | * @wq: workqueue to flush |
1da177e4 LT |
515 | * |
516 | * Forces execution of the workqueue and blocks until its completion. | |
517 | * This is typically used in driver shutdown handlers. | |
518 | * | |
fc2e4d70 ON |
519 | * We sleep until all works which were queued on entry have been handled, |
520 | * but we are not livelocked by new incoming ones. | |
1da177e4 LT |
521 | * |
522 | * This function used to run the workqueues itself. Now we just wait for the | |
523 | * helper threads to do it. | |
524 | */ | |
7ad5b3a5 | 525 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 526 | { |
e7577c50 | 527 | const struct cpumask *cpu_map = wq_cpu_map(wq); |
cce1a165 | 528 | int cpu; |
1da177e4 | 529 | |
b1f4ec17 | 530 | might_sleep(); |
3295f0ef IM |
531 | lock_map_acquire(&wq->lockdep_map); |
532 | lock_map_release(&wq->lockdep_map); | |
aa85ea5b | 533 | for_each_cpu(cpu, cpu_map) |
b1f4ec17 | 534 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
1da177e4 | 535 | } |
ae90dd5d | 536 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 537 | |
db700897 ON |
538 | /** |
539 | * flush_work - block until a work_struct's callback has terminated | |
540 | * @work: the work which is to be flushed | |
541 | * | |
a67da70d ON |
542 | * Returns false if @work has already terminated. |
543 | * | |
db700897 ON |
544 | * It is expected that, prior to calling flush_work(), the caller has |
545 | * arranged for the work to not be requeued, otherwise it doesn't make | |
546 | * sense to use this function. | |
547 | */ | |
548 | int flush_work(struct work_struct *work) | |
549 | { | |
550 | struct cpu_workqueue_struct *cwq; | |
551 | struct list_head *prev; | |
552 | struct wq_barrier barr; | |
553 | ||
554 | might_sleep(); | |
555 | cwq = get_wq_data(work); | |
556 | if (!cwq) | |
557 | return 0; | |
558 | ||
3295f0ef IM |
559 | lock_map_acquire(&cwq->wq->lockdep_map); |
560 | lock_map_release(&cwq->wq->lockdep_map); | |
a67da70d | 561 | |
db700897 ON |
562 | prev = NULL; |
563 | spin_lock_irq(&cwq->lock); | |
564 | if (!list_empty(&work->entry)) { | |
565 | /* | |
566 | * See the comment near try_to_grab_pending()->smp_rmb(). | |
567 | * If it was re-queued under us we are not going to wait. | |
568 | */ | |
569 | smp_rmb(); | |
570 | if (unlikely(cwq != get_wq_data(work))) | |
571 | goto out; | |
572 | prev = &work->entry; | |
573 | } else { | |
574 | if (cwq->current_work != work) | |
575 | goto out; | |
576 | prev = &cwq->worklist; | |
577 | } | |
578 | insert_wq_barrier(cwq, &barr, prev->next); | |
579 | out: | |
580 | spin_unlock_irq(&cwq->lock); | |
581 | if (!prev) | |
582 | return 0; | |
583 | ||
584 | wait_for_completion(&barr.done); | |
dc186ad7 | 585 | destroy_work_on_stack(&barr.work); |
db700897 ON |
586 | return 1; |
587 | } | |
588 | EXPORT_SYMBOL_GPL(flush_work); | |
589 | ||
6e84d644 | 590 | /* |
1f1f642e | 591 | * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, |
6e84d644 ON |
592 | * so this work can't be re-armed in any way. |
593 | */ | |
594 | static int try_to_grab_pending(struct work_struct *work) | |
595 | { | |
596 | struct cpu_workqueue_struct *cwq; | |
1f1f642e | 597 | int ret = -1; |
6e84d644 ON |
598 | |
599 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) | |
1f1f642e | 600 | return 0; |
6e84d644 ON |
601 | |
602 | /* | |
603 | * The queueing is in progress, or it is already queued. Try to | |
604 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
605 | */ | |
606 | ||
607 | cwq = get_wq_data(work); | |
608 | if (!cwq) | |
609 | return ret; | |
610 | ||
611 | spin_lock_irq(&cwq->lock); | |
612 | if (!list_empty(&work->entry)) { | |
613 | /* | |
614 | * This work is queued, but perhaps we locked the wrong cwq. | |
615 | * In that case we must see the new value after rmb(), see | |
616 | * insert_work()->wmb(). | |
617 | */ | |
618 | smp_rmb(); | |
619 | if (cwq == get_wq_data(work)) { | |
dc186ad7 | 620 | debug_work_deactivate(work); |
6e84d644 ON |
621 | list_del_init(&work->entry); |
622 | ret = 1; | |
623 | } | |
624 | } | |
625 | spin_unlock_irq(&cwq->lock); | |
626 | ||
627 | return ret; | |
628 | } | |
629 | ||
630 | static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | |
b89deed3 ON |
631 | struct work_struct *work) |
632 | { | |
633 | struct wq_barrier barr; | |
634 | int running = 0; | |
635 | ||
636 | spin_lock_irq(&cwq->lock); | |
637 | if (unlikely(cwq->current_work == work)) { | |
1a4d9b0a | 638 | insert_wq_barrier(cwq, &barr, cwq->worklist.next); |
b89deed3 ON |
639 | running = 1; |
640 | } | |
641 | spin_unlock_irq(&cwq->lock); | |
642 | ||
dc186ad7 | 643 | if (unlikely(running)) { |
b89deed3 | 644 | wait_for_completion(&barr.done); |
dc186ad7 TG |
645 | destroy_work_on_stack(&barr.work); |
646 | } | |
b89deed3 ON |
647 | } |
648 | ||
6e84d644 | 649 | static void wait_on_work(struct work_struct *work) |
b89deed3 ON |
650 | { |
651 | struct cpu_workqueue_struct *cwq; | |
28e53bdd | 652 | struct workqueue_struct *wq; |
e7577c50 | 653 | const struct cpumask *cpu_map; |
b1f4ec17 | 654 | int cpu; |
b89deed3 | 655 | |
f293ea92 ON |
656 | might_sleep(); |
657 | ||
3295f0ef IM |
658 | lock_map_acquire(&work->lockdep_map); |
659 | lock_map_release(&work->lockdep_map); | |
4e6045f1 | 660 | |
b89deed3 | 661 | cwq = get_wq_data(work); |
b89deed3 | 662 | if (!cwq) |
3af24433 | 663 | return; |
b89deed3 | 664 | |
28e53bdd ON |
665 | wq = cwq->wq; |
666 | cpu_map = wq_cpu_map(wq); | |
667 | ||
aa85ea5b | 668 | for_each_cpu(cpu, cpu_map) |
6e84d644 ON |
669 | wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
670 | } | |
671 | ||
1f1f642e ON |
672 | static int __cancel_work_timer(struct work_struct *work, |
673 | struct timer_list* timer) | |
674 | { | |
675 | int ret; | |
676 | ||
677 | do { | |
678 | ret = (timer && likely(del_timer(timer))); | |
679 | if (!ret) | |
680 | ret = try_to_grab_pending(work); | |
681 | wait_on_work(work); | |
682 | } while (unlikely(ret < 0)); | |
683 | ||
4d707b9f | 684 | clear_wq_data(work); |
1f1f642e ON |
685 | return ret; |
686 | } | |
687 | ||
6e84d644 ON |
688 | /** |
689 | * cancel_work_sync - block until a work_struct's callback has terminated | |
690 | * @work: the work which is to be flushed | |
691 | * | |
1f1f642e ON |
692 | * Returns true if @work was pending. |
693 | * | |
6e84d644 ON |
694 | * cancel_work_sync() will cancel the work if it is queued. If the work's |
695 | * callback appears to be running, cancel_work_sync() will block until it | |
696 | * has completed. | |
697 | * | |
698 | * It is possible to use this function if the work re-queues itself. It can | |
699 | * cancel the work even if it migrates to another workqueue, however in that | |
700 | * case it only guarantees that work->func() has completed on the last queued | |
701 | * workqueue. | |
702 | * | |
703 | * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not | |
704 | * pending, otherwise it goes into a busy-wait loop until the timer expires. | |
705 | * | |
706 | * The caller must ensure that workqueue_struct on which this work was last | |
707 | * queued can't be destroyed before this function returns. | |
708 | */ | |
1f1f642e | 709 | int cancel_work_sync(struct work_struct *work) |
6e84d644 | 710 | { |
1f1f642e | 711 | return __cancel_work_timer(work, NULL); |
b89deed3 | 712 | } |
28e53bdd | 713 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 714 | |
6e84d644 | 715 | /** |
f5a421a4 | 716 | * cancel_delayed_work_sync - reliably kill off a delayed work. |
6e84d644 ON |
717 | * @dwork: the delayed work struct |
718 | * | |
1f1f642e ON |
719 | * Returns true if @dwork was pending. |
720 | * | |
6e84d644 ON |
721 | * It is possible to use this function if @dwork rearms itself via queue_work() |
722 | * or queue_delayed_work(). See also the comment for cancel_work_sync(). | |
723 | */ | |
1f1f642e | 724 | int cancel_delayed_work_sync(struct delayed_work *dwork) |
6e84d644 | 725 | { |
1f1f642e | 726 | return __cancel_work_timer(&dwork->work, &dwork->timer); |
6e84d644 | 727 | } |
f5a421a4 | 728 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 729 | |
6e84d644 | 730 | static struct workqueue_struct *keventd_wq __read_mostly; |
1da177e4 | 731 | |
0fcb78c2 REB |
732 | /** |
733 | * schedule_work - put work task in global workqueue | |
734 | * @work: job to be done | |
735 | * | |
5b0f437d BVA |
736 | * Returns zero if @work was already on the kernel-global workqueue and |
737 | * non-zero otherwise. | |
738 | * | |
739 | * This puts a job in the kernel-global workqueue if it was not already | |
740 | * queued and leaves it in the same position on the kernel-global | |
741 | * workqueue otherwise. | |
0fcb78c2 | 742 | */ |
7ad5b3a5 | 743 | int schedule_work(struct work_struct *work) |
1da177e4 LT |
744 | { |
745 | return queue_work(keventd_wq, work); | |
746 | } | |
ae90dd5d | 747 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 748 | |
c1a220e7 ZR |
749 | /* |
750 | * schedule_work_on - put work task on a specific cpu | |
751 | * @cpu: cpu to put the work task on | |
752 | * @work: job to be done | |
753 | * | |
754 | * This puts a job on a specific cpu | |
755 | */ | |
756 | int schedule_work_on(int cpu, struct work_struct *work) | |
757 | { | |
758 | return queue_work_on(cpu, keventd_wq, work); | |
759 | } | |
760 | EXPORT_SYMBOL(schedule_work_on); | |
761 | ||
0fcb78c2 REB |
762 | /** |
763 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
764 | * @dwork: job to be done |
765 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
766 | * |
767 | * After waiting for a given time this puts a job in the kernel-global | |
768 | * workqueue. | |
769 | */ | |
7ad5b3a5 | 770 | int schedule_delayed_work(struct delayed_work *dwork, |
82f67cd9 | 771 | unsigned long delay) |
1da177e4 | 772 | { |
52bad64d | 773 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 774 | } |
ae90dd5d | 775 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 776 | |
8c53e463 LT |
777 | /** |
778 | * flush_delayed_work - block until a dwork_struct's callback has terminated | |
779 | * @dwork: the delayed work which is to be flushed | |
780 | * | |
781 | * Any timeout is cancelled, and any pending work is run immediately. | |
782 | */ | |
783 | void flush_delayed_work(struct delayed_work *dwork) | |
784 | { | |
785 | if (del_timer_sync(&dwork->timer)) { | |
786 | struct cpu_workqueue_struct *cwq; | |
47dd5be2 | 787 | cwq = wq_per_cpu(get_wq_data(&dwork->work)->wq, get_cpu()); |
8c53e463 LT |
788 | __queue_work(cwq, &dwork->work); |
789 | put_cpu(); | |
790 | } | |
791 | flush_work(&dwork->work); | |
792 | } | |
793 | EXPORT_SYMBOL(flush_delayed_work); | |
794 | ||
0fcb78c2 REB |
795 | /** |
796 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
797 | * @cpu: cpu to use | |
52bad64d | 798 | * @dwork: job to be done |
0fcb78c2 REB |
799 | * @delay: number of jiffies to wait |
800 | * | |
801 | * After waiting for a given time this puts a job in the kernel-global | |
802 | * workqueue on the specified CPU. | |
803 | */ | |
1da177e4 | 804 | int schedule_delayed_work_on(int cpu, |
52bad64d | 805 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 806 | { |
52bad64d | 807 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 808 | } |
ae90dd5d | 809 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 810 | |
b6136773 AM |
811 | /** |
812 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
813 | * @func: the function to call | |
b6136773 AM |
814 | * |
815 | * Returns zero on success. | |
816 | * Returns -ve errno on failure. | |
817 | * | |
b6136773 AM |
818 | * schedule_on_each_cpu() is very slow. |
819 | */ | |
65f27f38 | 820 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
821 | { |
822 | int cpu; | |
65a64464 | 823 | int orig = -1; |
b6136773 | 824 | struct work_struct *works; |
15316ba8 | 825 | |
b6136773 AM |
826 | works = alloc_percpu(struct work_struct); |
827 | if (!works) | |
15316ba8 | 828 | return -ENOMEM; |
b6136773 | 829 | |
93981800 TH |
830 | get_online_cpus(); |
831 | ||
65a64464 | 832 | /* |
93981800 TH |
833 | * When running in keventd don't schedule a work item on |
834 | * itself. Can just call directly because the work queue is | |
835 | * already bound. This also is faster. | |
65a64464 | 836 | */ |
93981800 | 837 | if (current_is_keventd()) |
65a64464 | 838 | orig = raw_smp_processor_id(); |
65a64464 | 839 | |
15316ba8 | 840 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
841 | struct work_struct *work = per_cpu_ptr(works, cpu); |
842 | ||
843 | INIT_WORK(work, func); | |
65a64464 | 844 | if (cpu != orig) |
93981800 | 845 | schedule_work_on(cpu, work); |
65a64464 | 846 | } |
93981800 TH |
847 | if (orig >= 0) |
848 | func(per_cpu_ptr(works, orig)); | |
849 | ||
850 | for_each_online_cpu(cpu) | |
851 | flush_work(per_cpu_ptr(works, cpu)); | |
852 | ||
95402b38 | 853 | put_online_cpus(); |
b6136773 | 854 | free_percpu(works); |
15316ba8 CL |
855 | return 0; |
856 | } | |
857 | ||
eef6a7d5 AS |
858 | /** |
859 | * flush_scheduled_work - ensure that any scheduled work has run to completion. | |
860 | * | |
861 | * Forces execution of the kernel-global workqueue and blocks until its | |
862 | * completion. | |
863 | * | |
864 | * Think twice before calling this function! It's very easy to get into | |
865 | * trouble if you don't take great care. Either of the following situations | |
866 | * will lead to deadlock: | |
867 | * | |
868 | * One of the work items currently on the workqueue needs to acquire | |
869 | * a lock held by your code or its caller. | |
870 | * | |
871 | * Your code is running in the context of a work routine. | |
872 | * | |
873 | * They will be detected by lockdep when they occur, but the first might not | |
874 | * occur very often. It depends on what work items are on the workqueue and | |
875 | * what locks they need, which you have no control over. | |
876 | * | |
877 | * In most situations flushing the entire workqueue is overkill; you merely | |
878 | * need to know that a particular work item isn't queued and isn't running. | |
879 | * In such cases you should use cancel_delayed_work_sync() or | |
880 | * cancel_work_sync() instead. | |
881 | */ | |
1da177e4 LT |
882 | void flush_scheduled_work(void) |
883 | { | |
884 | flush_workqueue(keventd_wq); | |
885 | } | |
ae90dd5d | 886 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 887 | |
1fa44eca JB |
888 | /** |
889 | * execute_in_process_context - reliably execute the routine with user context | |
890 | * @fn: the function to execute | |
1fa44eca JB |
891 | * @ew: guaranteed storage for the execute work structure (must |
892 | * be available when the work executes) | |
893 | * | |
894 | * Executes the function immediately if process context is available, | |
895 | * otherwise schedules the function for delayed execution. | |
896 | * | |
897 | * Returns: 0 - function was executed | |
898 | * 1 - function was scheduled for execution | |
899 | */ | |
65f27f38 | 900 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
901 | { |
902 | if (!in_interrupt()) { | |
65f27f38 | 903 | fn(&ew->work); |
1fa44eca JB |
904 | return 0; |
905 | } | |
906 | ||
65f27f38 | 907 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
908 | schedule_work(&ew->work); |
909 | ||
910 | return 1; | |
911 | } | |
912 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
913 | ||
1da177e4 LT |
914 | int keventd_up(void) |
915 | { | |
916 | return keventd_wq != NULL; | |
917 | } | |
918 | ||
919 | int current_is_keventd(void) | |
920 | { | |
921 | struct cpu_workqueue_struct *cwq; | |
d243769d | 922 | int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ |
1da177e4 LT |
923 | int ret = 0; |
924 | ||
925 | BUG_ON(!keventd_wq); | |
926 | ||
89ada679 | 927 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
928 | if (current == cwq->thread) |
929 | ret = 1; | |
930 | ||
931 | return ret; | |
932 | ||
933 | } | |
934 | ||
3af24433 ON |
935 | static struct cpu_workqueue_struct * |
936 | init_cpu_workqueue(struct workqueue_struct *wq, int cpu) | |
1da177e4 | 937 | { |
89ada679 | 938 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 | 939 | |
3af24433 ON |
940 | cwq->wq = wq; |
941 | spin_lock_init(&cwq->lock); | |
942 | INIT_LIST_HEAD(&cwq->worklist); | |
943 | init_waitqueue_head(&cwq->more_work); | |
944 | ||
945 | return cwq; | |
1da177e4 LT |
946 | } |
947 | ||
3af24433 ON |
948 | static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
949 | { | |
0d557dc9 | 950 | struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; |
3af24433 | 951 | struct workqueue_struct *wq = cwq->wq; |
6cc88bc4 | 952 | const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d"; |
3af24433 ON |
953 | struct task_struct *p; |
954 | ||
955 | p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu); | |
956 | /* | |
957 | * Nobody can add the work_struct to this cwq, | |
958 | * if (caller is __create_workqueue) | |
959 | * nobody should see this wq | |
960 | * else // caller is CPU_UP_PREPARE | |
961 | * cpu is not on cpu_online_map | |
962 | * so we can abort safely. | |
963 | */ | |
964 | if (IS_ERR(p)) | |
965 | return PTR_ERR(p); | |
0d557dc9 HC |
966 | if (cwq->wq->rt) |
967 | sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m); | |
3af24433 | 968 | cwq->thread = p; |
3af24433 | 969 | |
e1d8aa9f FW |
970 | trace_workqueue_creation(cwq->thread, cpu); |
971 | ||
3af24433 ON |
972 | return 0; |
973 | } | |
974 | ||
06ba38a9 ON |
975 | static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
976 | { | |
977 | struct task_struct *p = cwq->thread; | |
978 | ||
979 | if (p != NULL) { | |
980 | if (cpu >= 0) | |
981 | kthread_bind(p, cpu); | |
982 | wake_up_process(p); | |
983 | } | |
984 | } | |
985 | ||
4e6045f1 JB |
986 | struct workqueue_struct *__create_workqueue_key(const char *name, |
987 | int singlethread, | |
988 | int freezeable, | |
0d557dc9 | 989 | int rt, |
eb13ba87 JB |
990 | struct lock_class_key *key, |
991 | const char *lock_name) | |
1da177e4 | 992 | { |
1da177e4 | 993 | struct workqueue_struct *wq; |
3af24433 ON |
994 | struct cpu_workqueue_struct *cwq; |
995 | int err = 0, cpu; | |
1da177e4 | 996 | |
3af24433 ON |
997 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
998 | if (!wq) | |
999 | return NULL; | |
1000 | ||
1001 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); | |
1002 | if (!wq->cpu_wq) { | |
1003 | kfree(wq); | |
1004 | return NULL; | |
1005 | } | |
1006 | ||
1007 | wq->name = name; | |
eb13ba87 | 1008 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 1009 | wq->singlethread = singlethread; |
3af24433 | 1010 | wq->freezeable = freezeable; |
0d557dc9 | 1011 | wq->rt = rt; |
cce1a165 | 1012 | INIT_LIST_HEAD(&wq->list); |
3af24433 ON |
1013 | |
1014 | if (singlethread) { | |
3af24433 ON |
1015 | cwq = init_cpu_workqueue(wq, singlethread_cpu); |
1016 | err = create_workqueue_thread(cwq, singlethread_cpu); | |
06ba38a9 | 1017 | start_workqueue_thread(cwq, -1); |
3af24433 | 1018 | } else { |
3da1c84c | 1019 | cpu_maps_update_begin(); |
6af8bf3d ON |
1020 | /* |
1021 | * We must place this wq on list even if the code below fails. | |
1022 | * cpu_down(cpu) can remove cpu from cpu_populated_map before | |
1023 | * destroy_workqueue() takes the lock, in that case we leak | |
1024 | * cwq[cpu]->thread. | |
1025 | */ | |
95402b38 | 1026 | spin_lock(&workqueue_lock); |
3af24433 | 1027 | list_add(&wq->list, &workqueues); |
95402b38 | 1028 | spin_unlock(&workqueue_lock); |
6af8bf3d ON |
1029 | /* |
1030 | * We must initialize cwqs for each possible cpu even if we | |
1031 | * are going to call destroy_workqueue() finally. Otherwise | |
1032 | * cpu_up() can hit the uninitialized cwq once we drop the | |
1033 | * lock. | |
1034 | */ | |
3af24433 ON |
1035 | for_each_possible_cpu(cpu) { |
1036 | cwq = init_cpu_workqueue(wq, cpu); | |
1037 | if (err || !cpu_online(cpu)) | |
1038 | continue; | |
1039 | err = create_workqueue_thread(cwq, cpu); | |
06ba38a9 | 1040 | start_workqueue_thread(cwq, cpu); |
1da177e4 | 1041 | } |
3da1c84c | 1042 | cpu_maps_update_done(); |
3af24433 ON |
1043 | } |
1044 | ||
1045 | if (err) { | |
1046 | destroy_workqueue(wq); | |
1047 | wq = NULL; | |
1048 | } | |
1049 | return wq; | |
1050 | } | |
4e6045f1 | 1051 | EXPORT_SYMBOL_GPL(__create_workqueue_key); |
1da177e4 | 1052 | |
1e35eaa2 | 1053 | static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) |
3af24433 | 1054 | { |
14441960 | 1055 | /* |
3da1c84c ON |
1056 | * Our caller is either destroy_workqueue() or CPU_POST_DEAD, |
1057 | * cpu_add_remove_lock protects cwq->thread. | |
14441960 ON |
1058 | */ |
1059 | if (cwq->thread == NULL) | |
1060 | return; | |
3af24433 | 1061 | |
3295f0ef IM |
1062 | lock_map_acquire(&cwq->wq->lockdep_map); |
1063 | lock_map_release(&cwq->wq->lockdep_map); | |
4e6045f1 | 1064 | |
13c22168 | 1065 | flush_cpu_workqueue(cwq); |
14441960 | 1066 | /* |
3da1c84c | 1067 | * If the caller is CPU_POST_DEAD and cwq->worklist was not empty, |
13c22168 ON |
1068 | * a concurrent flush_workqueue() can insert a barrier after us. |
1069 | * However, in that case run_workqueue() won't return and check | |
1070 | * kthread_should_stop() until it flushes all work_struct's. | |
14441960 ON |
1071 | * When ->worklist becomes empty it is safe to exit because no |
1072 | * more work_structs can be queued on this cwq: flush_workqueue | |
1073 | * checks list_empty(), and a "normal" queue_work() can't use | |
1074 | * a dead CPU. | |
1075 | */ | |
e1d8aa9f | 1076 | trace_workqueue_destruction(cwq->thread); |
14441960 ON |
1077 | kthread_stop(cwq->thread); |
1078 | cwq->thread = NULL; | |
3af24433 ON |
1079 | } |
1080 | ||
1081 | /** | |
1082 | * destroy_workqueue - safely terminate a workqueue | |
1083 | * @wq: target workqueue | |
1084 | * | |
1085 | * Safely destroy a workqueue. All work currently pending will be done first. | |
1086 | */ | |
1087 | void destroy_workqueue(struct workqueue_struct *wq) | |
1088 | { | |
e7577c50 | 1089 | const struct cpumask *cpu_map = wq_cpu_map(wq); |
b1f4ec17 | 1090 | int cpu; |
3af24433 | 1091 | |
3da1c84c | 1092 | cpu_maps_update_begin(); |
95402b38 | 1093 | spin_lock(&workqueue_lock); |
b1f4ec17 | 1094 | list_del(&wq->list); |
95402b38 | 1095 | spin_unlock(&workqueue_lock); |
3af24433 | 1096 | |
aa85ea5b | 1097 | for_each_cpu(cpu, cpu_map) |
1e35eaa2 | 1098 | cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu)); |
3da1c84c | 1099 | cpu_maps_update_done(); |
9b41ea72 | 1100 | |
3af24433 ON |
1101 | free_percpu(wq->cpu_wq); |
1102 | kfree(wq); | |
1103 | } | |
1104 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
1105 | ||
1106 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
1107 | unsigned long action, | |
1108 | void *hcpu) | |
1109 | { | |
1110 | unsigned int cpu = (unsigned long)hcpu; | |
1111 | struct cpu_workqueue_struct *cwq; | |
1112 | struct workqueue_struct *wq; | |
8448502c | 1113 | int ret = NOTIFY_OK; |
3af24433 | 1114 | |
8bb78442 RW |
1115 | action &= ~CPU_TASKS_FROZEN; |
1116 | ||
3af24433 | 1117 | switch (action) { |
3af24433 | 1118 | case CPU_UP_PREPARE: |
e7577c50 | 1119 | cpumask_set_cpu(cpu, cpu_populated_map); |
3af24433 | 1120 | } |
8448502c | 1121 | undo: |
3af24433 ON |
1122 | list_for_each_entry(wq, &workqueues, list) { |
1123 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | |
1124 | ||
1125 | switch (action) { | |
1126 | case CPU_UP_PREPARE: | |
1127 | if (!create_workqueue_thread(cwq, cpu)) | |
1128 | break; | |
95402b38 GS |
1129 | printk(KERN_ERR "workqueue [%s] for %i failed\n", |
1130 | wq->name, cpu); | |
8448502c ON |
1131 | action = CPU_UP_CANCELED; |
1132 | ret = NOTIFY_BAD; | |
1133 | goto undo; | |
3af24433 ON |
1134 | |
1135 | case CPU_ONLINE: | |
06ba38a9 | 1136 | start_workqueue_thread(cwq, cpu); |
3af24433 ON |
1137 | break; |
1138 | ||
1139 | case CPU_UP_CANCELED: | |
06ba38a9 | 1140 | start_workqueue_thread(cwq, -1); |
3da1c84c | 1141 | case CPU_POST_DEAD: |
1e35eaa2 | 1142 | cleanup_workqueue_thread(cwq); |
3af24433 ON |
1143 | break; |
1144 | } | |
1da177e4 LT |
1145 | } |
1146 | ||
00dfcaf7 ON |
1147 | switch (action) { |
1148 | case CPU_UP_CANCELED: | |
3da1c84c | 1149 | case CPU_POST_DEAD: |
e7577c50 | 1150 | cpumask_clear_cpu(cpu, cpu_populated_map); |
00dfcaf7 ON |
1151 | } |
1152 | ||
8448502c | 1153 | return ret; |
1da177e4 | 1154 | } |
1da177e4 | 1155 | |
2d3854a3 | 1156 | #ifdef CONFIG_SMP |
8ccad40d | 1157 | |
2d3854a3 | 1158 | struct work_for_cpu { |
6b44003e | 1159 | struct completion completion; |
2d3854a3 RR |
1160 | long (*fn)(void *); |
1161 | void *arg; | |
1162 | long ret; | |
1163 | }; | |
1164 | ||
6b44003e | 1165 | static int do_work_for_cpu(void *_wfc) |
2d3854a3 | 1166 | { |
6b44003e | 1167 | struct work_for_cpu *wfc = _wfc; |
2d3854a3 | 1168 | wfc->ret = wfc->fn(wfc->arg); |
6b44003e AM |
1169 | complete(&wfc->completion); |
1170 | return 0; | |
2d3854a3 RR |
1171 | } |
1172 | ||
1173 | /** | |
1174 | * work_on_cpu - run a function in user context on a particular cpu | |
1175 | * @cpu: the cpu to run on | |
1176 | * @fn: the function to run | |
1177 | * @arg: the function arg | |
1178 | * | |
31ad9081 RR |
1179 | * This will return the value @fn returns. |
1180 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
6b44003e | 1181 | * The caller must not hold any locks which would prevent @fn from completing. |
2d3854a3 RR |
1182 | */ |
1183 | long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) | |
1184 | { | |
6b44003e AM |
1185 | struct task_struct *sub_thread; |
1186 | struct work_for_cpu wfc = { | |
1187 | .completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion), | |
1188 | .fn = fn, | |
1189 | .arg = arg, | |
1190 | }; | |
1191 | ||
1192 | sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu"); | |
1193 | if (IS_ERR(sub_thread)) | |
1194 | return PTR_ERR(sub_thread); | |
1195 | kthread_bind(sub_thread, cpu); | |
1196 | wake_up_process(sub_thread); | |
1197 | wait_for_completion(&wfc.completion); | |
2d3854a3 RR |
1198 | return wfc.ret; |
1199 | } | |
1200 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
1201 | #endif /* CONFIG_SMP */ | |
1202 | ||
c12920d1 | 1203 | void __init init_workqueues(void) |
1da177e4 | 1204 | { |
e7577c50 RR |
1205 | alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL); |
1206 | ||
1207 | cpumask_copy(cpu_populated_map, cpu_online_mask); | |
1208 | singlethread_cpu = cpumask_first(cpu_possible_mask); | |
1209 | cpu_singlethread_map = cpumask_of(singlethread_cpu); | |
1da177e4 LT |
1210 | hotcpu_notifier(workqueue_cpu_callback, 0); |
1211 | keventd_wq = create_workqueue("events"); | |
1212 | BUG_ON(!keventd_wq); | |
1213 | } |