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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> |
1da177e4 | 36 | |
4690c4ab TH |
37 | /* |
38 | * Structure fields follow one of the following exclusion rules. | |
39 | * | |
40 | * I: Set during initialization and read-only afterwards. | |
41 | * | |
42 | * L: cwq->lock protected. Access with cwq->lock held. | |
43 | * | |
44 | * W: workqueue_lock protected. | |
45 | */ | |
46 | ||
1da177e4 | 47 | /* |
f756d5e2 | 48 | * The per-CPU workqueue (if single thread, we always use the first |
0f900049 TH |
49 | * possible cpu). The lower WORK_STRUCT_FLAG_BITS of |
50 | * work_struct->data are used for flags and thus cwqs need to be | |
51 | * aligned at two's power of the number of flag bits. | |
1da177e4 LT |
52 | */ |
53 | struct cpu_workqueue_struct { | |
54 | ||
55 | spinlock_t lock; | |
56 | ||
1da177e4 LT |
57 | struct list_head worklist; |
58 | wait_queue_head_t more_work; | |
3af24433 | 59 | struct work_struct *current_work; |
1537663f | 60 | unsigned int cpu; |
1da177e4 | 61 | |
4690c4ab TH |
62 | struct workqueue_struct *wq; /* I: the owning workqueue */ |
63 | struct task_struct *thread; | |
0f900049 | 64 | }; |
1da177e4 LT |
65 | |
66 | /* | |
67 | * The externally visible workqueue abstraction is an array of | |
68 | * per-CPU workqueues: | |
69 | */ | |
70 | struct workqueue_struct { | |
97e37d7b | 71 | unsigned int flags; /* I: WQ_* flags */ |
4690c4ab TH |
72 | struct cpu_workqueue_struct *cpu_wq; /* I: cwq's */ |
73 | struct list_head list; /* W: list of all workqueues */ | |
74 | const char *name; /* I: workqueue name */ | |
4e6045f1 | 75 | #ifdef CONFIG_LOCKDEP |
4690c4ab | 76 | struct lockdep_map lockdep_map; |
4e6045f1 | 77 | #endif |
1da177e4 LT |
78 | }; |
79 | ||
dc186ad7 TG |
80 | #ifdef CONFIG_DEBUG_OBJECTS_WORK |
81 | ||
82 | static struct debug_obj_descr work_debug_descr; | |
83 | ||
84 | /* | |
85 | * fixup_init is called when: | |
86 | * - an active object is initialized | |
87 | */ | |
88 | static int work_fixup_init(void *addr, enum debug_obj_state state) | |
89 | { | |
90 | struct work_struct *work = addr; | |
91 | ||
92 | switch (state) { | |
93 | case ODEBUG_STATE_ACTIVE: | |
94 | cancel_work_sync(work); | |
95 | debug_object_init(work, &work_debug_descr); | |
96 | return 1; | |
97 | default: | |
98 | return 0; | |
99 | } | |
100 | } | |
101 | ||
102 | /* | |
103 | * fixup_activate is called when: | |
104 | * - an active object is activated | |
105 | * - an unknown object is activated (might be a statically initialized object) | |
106 | */ | |
107 | static int work_fixup_activate(void *addr, enum debug_obj_state state) | |
108 | { | |
109 | struct work_struct *work = addr; | |
110 | ||
111 | switch (state) { | |
112 | ||
113 | case ODEBUG_STATE_NOTAVAILABLE: | |
114 | /* | |
115 | * This is not really a fixup. The work struct was | |
116 | * statically initialized. We just make sure that it | |
117 | * is tracked in the object tracker. | |
118 | */ | |
22df02bb | 119 | if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) { |
dc186ad7 TG |
120 | debug_object_init(work, &work_debug_descr); |
121 | debug_object_activate(work, &work_debug_descr); | |
122 | return 0; | |
123 | } | |
124 | WARN_ON_ONCE(1); | |
125 | return 0; | |
126 | ||
127 | case ODEBUG_STATE_ACTIVE: | |
128 | WARN_ON(1); | |
129 | ||
130 | default: | |
131 | return 0; | |
132 | } | |
133 | } | |
134 | ||
135 | /* | |
136 | * fixup_free is called when: | |
137 | * - an active object is freed | |
138 | */ | |
139 | static int work_fixup_free(void *addr, enum debug_obj_state state) | |
140 | { | |
141 | struct work_struct *work = addr; | |
142 | ||
143 | switch (state) { | |
144 | case ODEBUG_STATE_ACTIVE: | |
145 | cancel_work_sync(work); | |
146 | debug_object_free(work, &work_debug_descr); | |
147 | return 1; | |
148 | default: | |
149 | return 0; | |
150 | } | |
151 | } | |
152 | ||
153 | static struct debug_obj_descr work_debug_descr = { | |
154 | .name = "work_struct", | |
155 | .fixup_init = work_fixup_init, | |
156 | .fixup_activate = work_fixup_activate, | |
157 | .fixup_free = work_fixup_free, | |
158 | }; | |
159 | ||
160 | static inline void debug_work_activate(struct work_struct *work) | |
161 | { | |
162 | debug_object_activate(work, &work_debug_descr); | |
163 | } | |
164 | ||
165 | static inline void debug_work_deactivate(struct work_struct *work) | |
166 | { | |
167 | debug_object_deactivate(work, &work_debug_descr); | |
168 | } | |
169 | ||
170 | void __init_work(struct work_struct *work, int onstack) | |
171 | { | |
172 | if (onstack) | |
173 | debug_object_init_on_stack(work, &work_debug_descr); | |
174 | else | |
175 | debug_object_init(work, &work_debug_descr); | |
176 | } | |
177 | EXPORT_SYMBOL_GPL(__init_work); | |
178 | ||
179 | void destroy_work_on_stack(struct work_struct *work) | |
180 | { | |
181 | debug_object_free(work, &work_debug_descr); | |
182 | } | |
183 | EXPORT_SYMBOL_GPL(destroy_work_on_stack); | |
184 | ||
185 | #else | |
186 | static inline void debug_work_activate(struct work_struct *work) { } | |
187 | static inline void debug_work_deactivate(struct work_struct *work) { } | |
188 | #endif | |
189 | ||
95402b38 GS |
190 | /* Serializes the accesses to the list of workqueues. */ |
191 | static DEFINE_SPINLOCK(workqueue_lock); | |
1da177e4 LT |
192 | static LIST_HEAD(workqueues); |
193 | ||
3af24433 | 194 | static int singlethread_cpu __read_mostly; |
1da177e4 | 195 | |
1537663f TH |
196 | static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, |
197 | struct workqueue_struct *wq) | |
b1f4ec17 | 198 | { |
1537663f | 199 | return per_cpu_ptr(wq->cpu_wq, cpu); |
b1f4ec17 ON |
200 | } |
201 | ||
1537663f TH |
202 | static struct cpu_workqueue_struct *target_cwq(unsigned int cpu, |
203 | struct workqueue_struct *wq) | |
a848e3b6 | 204 | { |
1537663f | 205 | if (unlikely(wq->flags & WQ_SINGLE_THREAD)) |
a848e3b6 | 206 | cpu = singlethread_cpu; |
1537663f | 207 | return get_cwq(cpu, wq); |
a848e3b6 ON |
208 | } |
209 | ||
4594bf15 DH |
210 | /* |
211 | * Set the workqueue on which a work item is to be run | |
212 | * - Must *only* be called if the pending flag is set | |
213 | */ | |
ed7c0fee | 214 | static inline void set_wq_data(struct work_struct *work, |
4690c4ab TH |
215 | struct cpu_workqueue_struct *cwq, |
216 | unsigned long extra_flags) | |
365970a1 | 217 | { |
4594bf15 | 218 | BUG_ON(!work_pending(work)); |
365970a1 | 219 | |
4690c4ab | 220 | atomic_long_set(&work->data, (unsigned long)cwq | work_static(work) | |
22df02bb | 221 | WORK_STRUCT_PENDING | extra_flags); |
365970a1 DH |
222 | } |
223 | ||
4d707b9f ON |
224 | /* |
225 | * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued. | |
226 | */ | |
227 | static inline void clear_wq_data(struct work_struct *work) | |
228 | { | |
4690c4ab | 229 | atomic_long_set(&work->data, work_static(work)); |
4d707b9f ON |
230 | } |
231 | ||
64166699 | 232 | static inline struct cpu_workqueue_struct *get_wq_data(struct work_struct *work) |
365970a1 | 233 | { |
64166699 TH |
234 | return (void *)(atomic_long_read(&work->data) & |
235 | WORK_STRUCT_WQ_DATA_MASK); | |
365970a1 DH |
236 | } |
237 | ||
4690c4ab TH |
238 | /** |
239 | * insert_work - insert a work into cwq | |
240 | * @cwq: cwq @work belongs to | |
241 | * @work: work to insert | |
242 | * @head: insertion point | |
243 | * @extra_flags: extra WORK_STRUCT_* flags to set | |
244 | * | |
245 | * Insert @work into @cwq after @head. | |
246 | * | |
247 | * CONTEXT: | |
248 | * spin_lock_irq(cwq->lock). | |
249 | */ | |
b89deed3 | 250 | static void insert_work(struct cpu_workqueue_struct *cwq, |
4690c4ab TH |
251 | struct work_struct *work, struct list_head *head, |
252 | unsigned int extra_flags) | |
b89deed3 | 253 | { |
4690c4ab TH |
254 | /* we own @work, set data and link */ |
255 | set_wq_data(work, cwq, extra_flags); | |
256 | ||
6e84d644 ON |
257 | /* |
258 | * Ensure that we get the right work->data if we see the | |
259 | * result of list_add() below, see try_to_grab_pending(). | |
260 | */ | |
261 | smp_wmb(); | |
4690c4ab | 262 | |
1a4d9b0a | 263 | list_add_tail(&work->entry, head); |
b89deed3 ON |
264 | wake_up(&cwq->more_work); |
265 | } | |
266 | ||
4690c4ab | 267 | static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, |
1da177e4 LT |
268 | struct work_struct *work) |
269 | { | |
1537663f | 270 | struct cpu_workqueue_struct *cwq = target_cwq(cpu, wq); |
1da177e4 LT |
271 | unsigned long flags; |
272 | ||
dc186ad7 | 273 | debug_work_activate(work); |
1da177e4 | 274 | spin_lock_irqsave(&cwq->lock, flags); |
4690c4ab TH |
275 | BUG_ON(!list_empty(&work->entry)); |
276 | insert_work(cwq, work, &cwq->worklist, 0); | |
1da177e4 LT |
277 | spin_unlock_irqrestore(&cwq->lock, flags); |
278 | } | |
279 | ||
0fcb78c2 REB |
280 | /** |
281 | * queue_work - queue work on a workqueue | |
282 | * @wq: workqueue to use | |
283 | * @work: work to queue | |
284 | * | |
057647fc | 285 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 | 286 | * |
00dfcaf7 ON |
287 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
288 | * it can be processed by another CPU. | |
1da177e4 | 289 | */ |
7ad5b3a5 | 290 | int queue_work(struct workqueue_struct *wq, struct work_struct *work) |
1da177e4 | 291 | { |
ef1ca236 ON |
292 | int ret; |
293 | ||
294 | ret = queue_work_on(get_cpu(), wq, work); | |
295 | put_cpu(); | |
296 | ||
1da177e4 LT |
297 | return ret; |
298 | } | |
ae90dd5d | 299 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 300 | |
c1a220e7 ZR |
301 | /** |
302 | * queue_work_on - queue work on specific cpu | |
303 | * @cpu: CPU number to execute work on | |
304 | * @wq: workqueue to use | |
305 | * @work: work to queue | |
306 | * | |
307 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
308 | * | |
309 | * We queue the work to a specific CPU, the caller must ensure it | |
310 | * can't go away. | |
311 | */ | |
312 | int | |
313 | queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) | |
314 | { | |
315 | int ret = 0; | |
316 | ||
22df02bb | 317 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
4690c4ab | 318 | __queue_work(cpu, wq, work); |
c1a220e7 ZR |
319 | ret = 1; |
320 | } | |
321 | return ret; | |
322 | } | |
323 | EXPORT_SYMBOL_GPL(queue_work_on); | |
324 | ||
6d141c3f | 325 | static void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 326 | { |
52bad64d | 327 | struct delayed_work *dwork = (struct delayed_work *)__data; |
ed7c0fee | 328 | struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
1da177e4 | 329 | |
4690c4ab | 330 | __queue_work(smp_processor_id(), cwq->wq, &dwork->work); |
1da177e4 LT |
331 | } |
332 | ||
0fcb78c2 REB |
333 | /** |
334 | * queue_delayed_work - queue work on a workqueue after delay | |
335 | * @wq: workqueue to use | |
af9997e4 | 336 | * @dwork: delayable work to queue |
0fcb78c2 REB |
337 | * @delay: number of jiffies to wait before queueing |
338 | * | |
057647fc | 339 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 340 | */ |
7ad5b3a5 | 341 | int queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 342 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 343 | { |
52bad64d | 344 | if (delay == 0) |
63bc0362 | 345 | return queue_work(wq, &dwork->work); |
1da177e4 | 346 | |
63bc0362 | 347 | return queue_delayed_work_on(-1, wq, dwork, delay); |
1da177e4 | 348 | } |
ae90dd5d | 349 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 350 | |
0fcb78c2 REB |
351 | /** |
352 | * queue_delayed_work_on - queue work on specific CPU after delay | |
353 | * @cpu: CPU number to execute work on | |
354 | * @wq: workqueue to use | |
af9997e4 | 355 | * @dwork: work to queue |
0fcb78c2 REB |
356 | * @delay: number of jiffies to wait before queueing |
357 | * | |
057647fc | 358 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 359 | */ |
7a6bc1cd | 360 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 361 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
362 | { |
363 | int ret = 0; | |
52bad64d DH |
364 | struct timer_list *timer = &dwork->timer; |
365 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 366 | |
22df02bb | 367 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
7a6bc1cd VP |
368 | BUG_ON(timer_pending(timer)); |
369 | BUG_ON(!list_empty(&work->entry)); | |
370 | ||
8a3e77cc AL |
371 | timer_stats_timer_set_start_info(&dwork->timer); |
372 | ||
ed7c0fee | 373 | /* This stores cwq for the moment, for the timer_fn */ |
1537663f | 374 | set_wq_data(work, target_cwq(raw_smp_processor_id(), wq), 0); |
7a6bc1cd | 375 | timer->expires = jiffies + delay; |
52bad64d | 376 | timer->data = (unsigned long)dwork; |
7a6bc1cd | 377 | timer->function = delayed_work_timer_fn; |
63bc0362 ON |
378 | |
379 | if (unlikely(cpu >= 0)) | |
380 | add_timer_on(timer, cpu); | |
381 | else | |
382 | add_timer(timer); | |
7a6bc1cd VP |
383 | ret = 1; |
384 | } | |
385 | return ret; | |
386 | } | |
ae90dd5d | 387 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 388 | |
a62428c0 TH |
389 | /** |
390 | * process_one_work - process single work | |
391 | * @cwq: cwq to process work for | |
392 | * @work: work to process | |
393 | * | |
394 | * Process @work. This function contains all the logics necessary to | |
395 | * process a single work including synchronization against and | |
396 | * interaction with other workers on the same cpu, queueing and | |
397 | * flushing. As long as context requirement is met, any worker can | |
398 | * call this function to process a work. | |
399 | * | |
400 | * CONTEXT: | |
401 | * spin_lock_irq(cwq->lock) which is released and regrabbed. | |
402 | */ | |
403 | static void process_one_work(struct cpu_workqueue_struct *cwq, | |
404 | struct work_struct *work) | |
405 | { | |
406 | work_func_t f = work->func; | |
407 | #ifdef CONFIG_LOCKDEP | |
408 | /* | |
409 | * It is permissible to free the struct work_struct from | |
410 | * inside the function that is called from it, this we need to | |
411 | * take into account for lockdep too. To avoid bogus "held | |
412 | * lock freed" warnings as well as problems when looking into | |
413 | * work->lockdep_map, make a copy and use that here. | |
414 | */ | |
415 | struct lockdep_map lockdep_map = work->lockdep_map; | |
416 | #endif | |
417 | /* claim and process */ | |
a62428c0 TH |
418 | debug_work_deactivate(work); |
419 | cwq->current_work = work; | |
420 | list_del_init(&work->entry); | |
421 | ||
422 | spin_unlock_irq(&cwq->lock); | |
423 | ||
424 | BUG_ON(get_wq_data(work) != cwq); | |
425 | work_clear_pending(work); | |
426 | lock_map_acquire(&cwq->wq->lockdep_map); | |
427 | lock_map_acquire(&lockdep_map); | |
428 | f(work); | |
429 | lock_map_release(&lockdep_map); | |
430 | lock_map_release(&cwq->wq->lockdep_map); | |
431 | ||
432 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { | |
433 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
434 | "%s/0x%08x/%d\n", | |
435 | current->comm, preempt_count(), task_pid_nr(current)); | |
436 | printk(KERN_ERR " last function: "); | |
437 | print_symbol("%s\n", (unsigned long)f); | |
438 | debug_show_held_locks(current); | |
439 | dump_stack(); | |
440 | } | |
441 | ||
442 | spin_lock_irq(&cwq->lock); | |
443 | ||
444 | /* we're done with it, release */ | |
445 | cwq->current_work = NULL; | |
446 | } | |
447 | ||
858119e1 | 448 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 449 | { |
f293ea92 | 450 | spin_lock_irq(&cwq->lock); |
1da177e4 LT |
451 | while (!list_empty(&cwq->worklist)) { |
452 | struct work_struct *work = list_entry(cwq->worklist.next, | |
453 | struct work_struct, entry); | |
a62428c0 | 454 | process_one_work(cwq, work); |
1da177e4 | 455 | } |
f293ea92 | 456 | spin_unlock_irq(&cwq->lock); |
1da177e4 LT |
457 | } |
458 | ||
4690c4ab TH |
459 | /** |
460 | * worker_thread - the worker thread function | |
461 | * @__cwq: cwq to serve | |
462 | * | |
463 | * The cwq worker thread function. | |
464 | */ | |
1da177e4 LT |
465 | static int worker_thread(void *__cwq) |
466 | { | |
467 | struct cpu_workqueue_struct *cwq = __cwq; | |
3af24433 | 468 | DEFINE_WAIT(wait); |
1da177e4 | 469 | |
97e37d7b | 470 | if (cwq->wq->flags & WQ_FREEZEABLE) |
83144186 | 471 | set_freezable(); |
1da177e4 | 472 | |
3af24433 | 473 | for (;;) { |
3af24433 | 474 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
14441960 ON |
475 | if (!freezing(current) && |
476 | !kthread_should_stop() && | |
477 | list_empty(&cwq->worklist)) | |
1da177e4 | 478 | schedule(); |
3af24433 ON |
479 | finish_wait(&cwq->more_work, &wait); |
480 | ||
85f4186a ON |
481 | try_to_freeze(); |
482 | ||
14441960 | 483 | if (kthread_should_stop()) |
3af24433 | 484 | break; |
1da177e4 | 485 | |
1537663f TH |
486 | if (unlikely(!cpumask_equal(&cwq->thread->cpus_allowed, |
487 | get_cpu_mask(cwq->cpu)))) | |
488 | set_cpus_allowed_ptr(cwq->thread, | |
489 | get_cpu_mask(cwq->cpu)); | |
3af24433 | 490 | run_workqueue(cwq); |
1da177e4 | 491 | } |
3af24433 | 492 | |
1da177e4 LT |
493 | return 0; |
494 | } | |
495 | ||
fc2e4d70 ON |
496 | struct wq_barrier { |
497 | struct work_struct work; | |
498 | struct completion done; | |
499 | }; | |
500 | ||
501 | static void wq_barrier_func(struct work_struct *work) | |
502 | { | |
503 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
504 | complete(&barr->done); | |
505 | } | |
506 | ||
4690c4ab TH |
507 | /** |
508 | * insert_wq_barrier - insert a barrier work | |
509 | * @cwq: cwq to insert barrier into | |
510 | * @barr: wq_barrier to insert | |
511 | * @head: insertion point | |
512 | * | |
513 | * Insert barrier @barr into @cwq before @head. | |
514 | * | |
515 | * CONTEXT: | |
516 | * spin_lock_irq(cwq->lock). | |
517 | */ | |
83c22520 | 518 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
1a4d9b0a | 519 | struct wq_barrier *barr, struct list_head *head) |
fc2e4d70 | 520 | { |
dc186ad7 TG |
521 | /* |
522 | * debugobject calls are safe here even with cwq->lock locked | |
523 | * as we know for sure that this will not trigger any of the | |
524 | * checks and call back into the fixup functions where we | |
525 | * might deadlock. | |
526 | */ | |
527 | INIT_WORK_ON_STACK(&barr->work, wq_barrier_func); | |
22df02bb | 528 | __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); |
fc2e4d70 | 529 | init_completion(&barr->done); |
83c22520 | 530 | |
dc186ad7 | 531 | debug_work_activate(&barr->work); |
4690c4ab | 532 | insert_work(cwq, &barr->work, head, 0); |
fc2e4d70 ON |
533 | } |
534 | ||
14441960 | 535 | static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 | 536 | { |
2355b70f LJ |
537 | int active = 0; |
538 | struct wq_barrier barr; | |
1da177e4 | 539 | |
2355b70f | 540 | WARN_ON(cwq->thread == current); |
1da177e4 | 541 | |
2355b70f LJ |
542 | spin_lock_irq(&cwq->lock); |
543 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | |
544 | insert_wq_barrier(cwq, &barr, &cwq->worklist); | |
545 | active = 1; | |
1da177e4 | 546 | } |
2355b70f LJ |
547 | spin_unlock_irq(&cwq->lock); |
548 | ||
dc186ad7 | 549 | if (active) { |
2355b70f | 550 | wait_for_completion(&barr.done); |
dc186ad7 TG |
551 | destroy_work_on_stack(&barr.work); |
552 | } | |
14441960 ON |
553 | |
554 | return active; | |
1da177e4 LT |
555 | } |
556 | ||
0fcb78c2 | 557 | /** |
1da177e4 | 558 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 559 | * @wq: workqueue to flush |
1da177e4 LT |
560 | * |
561 | * Forces execution of the workqueue and blocks until its completion. | |
562 | * This is typically used in driver shutdown handlers. | |
563 | * | |
fc2e4d70 ON |
564 | * We sleep until all works which were queued on entry have been handled, |
565 | * but we are not livelocked by new incoming ones. | |
1da177e4 | 566 | */ |
7ad5b3a5 | 567 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 568 | { |
cce1a165 | 569 | int cpu; |
1da177e4 | 570 | |
b1f4ec17 | 571 | might_sleep(); |
3295f0ef IM |
572 | lock_map_acquire(&wq->lockdep_map); |
573 | lock_map_release(&wq->lockdep_map); | |
1537663f TH |
574 | for_each_possible_cpu(cpu) |
575 | flush_cpu_workqueue(get_cwq(cpu, wq)); | |
1da177e4 | 576 | } |
ae90dd5d | 577 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 578 | |
db700897 ON |
579 | /** |
580 | * flush_work - block until a work_struct's callback has terminated | |
581 | * @work: the work which is to be flushed | |
582 | * | |
a67da70d ON |
583 | * Returns false if @work has already terminated. |
584 | * | |
db700897 ON |
585 | * It is expected that, prior to calling flush_work(), the caller has |
586 | * arranged for the work to not be requeued, otherwise it doesn't make | |
587 | * sense to use this function. | |
588 | */ | |
589 | int flush_work(struct work_struct *work) | |
590 | { | |
591 | struct cpu_workqueue_struct *cwq; | |
592 | struct list_head *prev; | |
593 | struct wq_barrier barr; | |
594 | ||
595 | might_sleep(); | |
596 | cwq = get_wq_data(work); | |
597 | if (!cwq) | |
598 | return 0; | |
599 | ||
3295f0ef IM |
600 | lock_map_acquire(&cwq->wq->lockdep_map); |
601 | lock_map_release(&cwq->wq->lockdep_map); | |
a67da70d | 602 | |
db700897 ON |
603 | spin_lock_irq(&cwq->lock); |
604 | if (!list_empty(&work->entry)) { | |
605 | /* | |
606 | * See the comment near try_to_grab_pending()->smp_rmb(). | |
607 | * If it was re-queued under us we are not going to wait. | |
608 | */ | |
609 | smp_rmb(); | |
610 | if (unlikely(cwq != get_wq_data(work))) | |
4690c4ab | 611 | goto already_gone; |
db700897 ON |
612 | prev = &work->entry; |
613 | } else { | |
614 | if (cwq->current_work != work) | |
4690c4ab | 615 | goto already_gone; |
db700897 ON |
616 | prev = &cwq->worklist; |
617 | } | |
618 | insert_wq_barrier(cwq, &barr, prev->next); | |
db700897 | 619 | |
4690c4ab | 620 | spin_unlock_irq(&cwq->lock); |
db700897 | 621 | wait_for_completion(&barr.done); |
dc186ad7 | 622 | destroy_work_on_stack(&barr.work); |
db700897 | 623 | return 1; |
4690c4ab TH |
624 | already_gone: |
625 | spin_unlock_irq(&cwq->lock); | |
626 | return 0; | |
db700897 ON |
627 | } |
628 | EXPORT_SYMBOL_GPL(flush_work); | |
629 | ||
6e84d644 | 630 | /* |
1f1f642e | 631 | * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, |
6e84d644 ON |
632 | * so this work can't be re-armed in any way. |
633 | */ | |
634 | static int try_to_grab_pending(struct work_struct *work) | |
635 | { | |
636 | struct cpu_workqueue_struct *cwq; | |
1f1f642e | 637 | int ret = -1; |
6e84d644 | 638 | |
22df02bb | 639 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) |
1f1f642e | 640 | return 0; |
6e84d644 ON |
641 | |
642 | /* | |
643 | * The queueing is in progress, or it is already queued. Try to | |
644 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
645 | */ | |
646 | ||
647 | cwq = get_wq_data(work); | |
648 | if (!cwq) | |
649 | return ret; | |
650 | ||
651 | spin_lock_irq(&cwq->lock); | |
652 | if (!list_empty(&work->entry)) { | |
653 | /* | |
654 | * This work is queued, but perhaps we locked the wrong cwq. | |
655 | * In that case we must see the new value after rmb(), see | |
656 | * insert_work()->wmb(). | |
657 | */ | |
658 | smp_rmb(); | |
659 | if (cwq == get_wq_data(work)) { | |
dc186ad7 | 660 | debug_work_deactivate(work); |
6e84d644 ON |
661 | list_del_init(&work->entry); |
662 | ret = 1; | |
663 | } | |
664 | } | |
665 | spin_unlock_irq(&cwq->lock); | |
666 | ||
667 | return ret; | |
668 | } | |
669 | ||
670 | static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | |
b89deed3 ON |
671 | struct work_struct *work) |
672 | { | |
673 | struct wq_barrier barr; | |
674 | int running = 0; | |
675 | ||
676 | spin_lock_irq(&cwq->lock); | |
677 | if (unlikely(cwq->current_work == work)) { | |
1a4d9b0a | 678 | insert_wq_barrier(cwq, &barr, cwq->worklist.next); |
b89deed3 ON |
679 | running = 1; |
680 | } | |
681 | spin_unlock_irq(&cwq->lock); | |
682 | ||
dc186ad7 | 683 | if (unlikely(running)) { |
b89deed3 | 684 | wait_for_completion(&barr.done); |
dc186ad7 TG |
685 | destroy_work_on_stack(&barr.work); |
686 | } | |
b89deed3 ON |
687 | } |
688 | ||
6e84d644 | 689 | static void wait_on_work(struct work_struct *work) |
b89deed3 ON |
690 | { |
691 | struct cpu_workqueue_struct *cwq; | |
28e53bdd | 692 | struct workqueue_struct *wq; |
b1f4ec17 | 693 | int cpu; |
b89deed3 | 694 | |
f293ea92 ON |
695 | might_sleep(); |
696 | ||
3295f0ef IM |
697 | lock_map_acquire(&work->lockdep_map); |
698 | lock_map_release(&work->lockdep_map); | |
4e6045f1 | 699 | |
b89deed3 | 700 | cwq = get_wq_data(work); |
b89deed3 | 701 | if (!cwq) |
3af24433 | 702 | return; |
b89deed3 | 703 | |
28e53bdd | 704 | wq = cwq->wq; |
28e53bdd | 705 | |
1537663f | 706 | for_each_possible_cpu(cpu) |
4690c4ab | 707 | wait_on_cpu_work(get_cwq(cpu, wq), work); |
6e84d644 ON |
708 | } |
709 | ||
1f1f642e ON |
710 | static int __cancel_work_timer(struct work_struct *work, |
711 | struct timer_list* timer) | |
712 | { | |
713 | int ret; | |
714 | ||
715 | do { | |
716 | ret = (timer && likely(del_timer(timer))); | |
717 | if (!ret) | |
718 | ret = try_to_grab_pending(work); | |
719 | wait_on_work(work); | |
720 | } while (unlikely(ret < 0)); | |
721 | ||
4d707b9f | 722 | clear_wq_data(work); |
1f1f642e ON |
723 | return ret; |
724 | } | |
725 | ||
6e84d644 ON |
726 | /** |
727 | * cancel_work_sync - block until a work_struct's callback has terminated | |
728 | * @work: the work which is to be flushed | |
729 | * | |
1f1f642e ON |
730 | * Returns true if @work was pending. |
731 | * | |
6e84d644 ON |
732 | * cancel_work_sync() will cancel the work if it is queued. If the work's |
733 | * callback appears to be running, cancel_work_sync() will block until it | |
734 | * has completed. | |
735 | * | |
736 | * It is possible to use this function if the work re-queues itself. It can | |
737 | * cancel the work even if it migrates to another workqueue, however in that | |
738 | * case it only guarantees that work->func() has completed on the last queued | |
739 | * workqueue. | |
740 | * | |
741 | * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not | |
742 | * pending, otherwise it goes into a busy-wait loop until the timer expires. | |
743 | * | |
744 | * The caller must ensure that workqueue_struct on which this work was last | |
745 | * queued can't be destroyed before this function returns. | |
746 | */ | |
1f1f642e | 747 | int cancel_work_sync(struct work_struct *work) |
6e84d644 | 748 | { |
1f1f642e | 749 | return __cancel_work_timer(work, NULL); |
b89deed3 | 750 | } |
28e53bdd | 751 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 752 | |
6e84d644 | 753 | /** |
f5a421a4 | 754 | * cancel_delayed_work_sync - reliably kill off a delayed work. |
6e84d644 ON |
755 | * @dwork: the delayed work struct |
756 | * | |
1f1f642e ON |
757 | * Returns true if @dwork was pending. |
758 | * | |
6e84d644 ON |
759 | * It is possible to use this function if @dwork rearms itself via queue_work() |
760 | * or queue_delayed_work(). See also the comment for cancel_work_sync(). | |
761 | */ | |
1f1f642e | 762 | int cancel_delayed_work_sync(struct delayed_work *dwork) |
6e84d644 | 763 | { |
1f1f642e | 764 | return __cancel_work_timer(&dwork->work, &dwork->timer); |
6e84d644 | 765 | } |
f5a421a4 | 766 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 767 | |
6e84d644 | 768 | static struct workqueue_struct *keventd_wq __read_mostly; |
1da177e4 | 769 | |
0fcb78c2 REB |
770 | /** |
771 | * schedule_work - put work task in global workqueue | |
772 | * @work: job to be done | |
773 | * | |
5b0f437d BVA |
774 | * Returns zero if @work was already on the kernel-global workqueue and |
775 | * non-zero otherwise. | |
776 | * | |
777 | * This puts a job in the kernel-global workqueue if it was not already | |
778 | * queued and leaves it in the same position on the kernel-global | |
779 | * workqueue otherwise. | |
0fcb78c2 | 780 | */ |
7ad5b3a5 | 781 | int schedule_work(struct work_struct *work) |
1da177e4 LT |
782 | { |
783 | return queue_work(keventd_wq, work); | |
784 | } | |
ae90dd5d | 785 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 786 | |
c1a220e7 ZR |
787 | /* |
788 | * schedule_work_on - put work task on a specific cpu | |
789 | * @cpu: cpu to put the work task on | |
790 | * @work: job to be done | |
791 | * | |
792 | * This puts a job on a specific cpu | |
793 | */ | |
794 | int schedule_work_on(int cpu, struct work_struct *work) | |
795 | { | |
796 | return queue_work_on(cpu, keventd_wq, work); | |
797 | } | |
798 | EXPORT_SYMBOL(schedule_work_on); | |
799 | ||
0fcb78c2 REB |
800 | /** |
801 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
802 | * @dwork: job to be done |
803 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
804 | * |
805 | * After waiting for a given time this puts a job in the kernel-global | |
806 | * workqueue. | |
807 | */ | |
7ad5b3a5 | 808 | int schedule_delayed_work(struct delayed_work *dwork, |
82f67cd9 | 809 | unsigned long delay) |
1da177e4 | 810 | { |
52bad64d | 811 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 812 | } |
ae90dd5d | 813 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 814 | |
8c53e463 LT |
815 | /** |
816 | * flush_delayed_work - block until a dwork_struct's callback has terminated | |
817 | * @dwork: the delayed work which is to be flushed | |
818 | * | |
819 | * Any timeout is cancelled, and any pending work is run immediately. | |
820 | */ | |
821 | void flush_delayed_work(struct delayed_work *dwork) | |
822 | { | |
823 | if (del_timer_sync(&dwork->timer)) { | |
4690c4ab TH |
824 | __queue_work(get_cpu(), get_wq_data(&dwork->work)->wq, |
825 | &dwork->work); | |
8c53e463 LT |
826 | put_cpu(); |
827 | } | |
828 | flush_work(&dwork->work); | |
829 | } | |
830 | EXPORT_SYMBOL(flush_delayed_work); | |
831 | ||
0fcb78c2 REB |
832 | /** |
833 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
834 | * @cpu: cpu to use | |
52bad64d | 835 | * @dwork: job to be done |
0fcb78c2 REB |
836 | * @delay: number of jiffies to wait |
837 | * | |
838 | * After waiting for a given time this puts a job in the kernel-global | |
839 | * workqueue on the specified CPU. | |
840 | */ | |
1da177e4 | 841 | int schedule_delayed_work_on(int cpu, |
52bad64d | 842 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 843 | { |
52bad64d | 844 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 845 | } |
ae90dd5d | 846 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 847 | |
b6136773 AM |
848 | /** |
849 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
850 | * @func: the function to call | |
b6136773 AM |
851 | * |
852 | * Returns zero on success. | |
853 | * Returns -ve errno on failure. | |
854 | * | |
b6136773 AM |
855 | * schedule_on_each_cpu() is very slow. |
856 | */ | |
65f27f38 | 857 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
858 | { |
859 | int cpu; | |
65a64464 | 860 | int orig = -1; |
b6136773 | 861 | struct work_struct *works; |
15316ba8 | 862 | |
b6136773 AM |
863 | works = alloc_percpu(struct work_struct); |
864 | if (!works) | |
15316ba8 | 865 | return -ENOMEM; |
b6136773 | 866 | |
93981800 TH |
867 | get_online_cpus(); |
868 | ||
65a64464 | 869 | /* |
93981800 TH |
870 | * When running in keventd don't schedule a work item on |
871 | * itself. Can just call directly because the work queue is | |
872 | * already bound. This also is faster. | |
65a64464 | 873 | */ |
93981800 | 874 | if (current_is_keventd()) |
65a64464 | 875 | orig = raw_smp_processor_id(); |
65a64464 | 876 | |
15316ba8 | 877 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
878 | struct work_struct *work = per_cpu_ptr(works, cpu); |
879 | ||
880 | INIT_WORK(work, func); | |
65a64464 | 881 | if (cpu != orig) |
93981800 | 882 | schedule_work_on(cpu, work); |
65a64464 | 883 | } |
93981800 TH |
884 | if (orig >= 0) |
885 | func(per_cpu_ptr(works, orig)); | |
886 | ||
887 | for_each_online_cpu(cpu) | |
888 | flush_work(per_cpu_ptr(works, cpu)); | |
889 | ||
95402b38 | 890 | put_online_cpus(); |
b6136773 | 891 | free_percpu(works); |
15316ba8 CL |
892 | return 0; |
893 | } | |
894 | ||
eef6a7d5 AS |
895 | /** |
896 | * flush_scheduled_work - ensure that any scheduled work has run to completion. | |
897 | * | |
898 | * Forces execution of the kernel-global workqueue and blocks until its | |
899 | * completion. | |
900 | * | |
901 | * Think twice before calling this function! It's very easy to get into | |
902 | * trouble if you don't take great care. Either of the following situations | |
903 | * will lead to deadlock: | |
904 | * | |
905 | * One of the work items currently on the workqueue needs to acquire | |
906 | * a lock held by your code or its caller. | |
907 | * | |
908 | * Your code is running in the context of a work routine. | |
909 | * | |
910 | * They will be detected by lockdep when they occur, but the first might not | |
911 | * occur very often. It depends on what work items are on the workqueue and | |
912 | * what locks they need, which you have no control over. | |
913 | * | |
914 | * In most situations flushing the entire workqueue is overkill; you merely | |
915 | * need to know that a particular work item isn't queued and isn't running. | |
916 | * In such cases you should use cancel_delayed_work_sync() or | |
917 | * cancel_work_sync() instead. | |
918 | */ | |
1da177e4 LT |
919 | void flush_scheduled_work(void) |
920 | { | |
921 | flush_workqueue(keventd_wq); | |
922 | } | |
ae90dd5d | 923 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 924 | |
1fa44eca JB |
925 | /** |
926 | * execute_in_process_context - reliably execute the routine with user context | |
927 | * @fn: the function to execute | |
1fa44eca JB |
928 | * @ew: guaranteed storage for the execute work structure (must |
929 | * be available when the work executes) | |
930 | * | |
931 | * Executes the function immediately if process context is available, | |
932 | * otherwise schedules the function for delayed execution. | |
933 | * | |
934 | * Returns: 0 - function was executed | |
935 | * 1 - function was scheduled for execution | |
936 | */ | |
65f27f38 | 937 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
938 | { |
939 | if (!in_interrupt()) { | |
65f27f38 | 940 | fn(&ew->work); |
1fa44eca JB |
941 | return 0; |
942 | } | |
943 | ||
65f27f38 | 944 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
945 | schedule_work(&ew->work); |
946 | ||
947 | return 1; | |
948 | } | |
949 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
950 | ||
1da177e4 LT |
951 | int keventd_up(void) |
952 | { | |
953 | return keventd_wq != NULL; | |
954 | } | |
955 | ||
956 | int current_is_keventd(void) | |
957 | { | |
958 | struct cpu_workqueue_struct *cwq; | |
d243769d | 959 | int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ |
1da177e4 LT |
960 | int ret = 0; |
961 | ||
962 | BUG_ON(!keventd_wq); | |
963 | ||
1537663f | 964 | cwq = get_cwq(cpu, keventd_wq); |
1da177e4 LT |
965 | if (current == cwq->thread) |
966 | ret = 1; | |
967 | ||
968 | return ret; | |
969 | ||
970 | } | |
971 | ||
0f900049 TH |
972 | static struct cpu_workqueue_struct *alloc_cwqs(void) |
973 | { | |
974 | /* | |
975 | * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. | |
976 | * Make sure that the alignment isn't lower than that of | |
977 | * unsigned long long. | |
978 | */ | |
979 | const size_t size = sizeof(struct cpu_workqueue_struct); | |
980 | const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, | |
981 | __alignof__(unsigned long long)); | |
982 | struct cpu_workqueue_struct *cwqs; | |
983 | #ifndef CONFIG_SMP | |
984 | void *ptr; | |
985 | ||
986 | /* | |
987 | * On UP, percpu allocator doesn't honor alignment parameter | |
988 | * and simply uses arch-dependent default. Allocate enough | |
989 | * room to align cwq and put an extra pointer at the end | |
990 | * pointing back to the originally allocated pointer which | |
991 | * will be used for free. | |
992 | * | |
993 | * FIXME: This really belongs to UP percpu code. Update UP | |
994 | * percpu code to honor alignment and remove this ugliness. | |
995 | */ | |
996 | ptr = __alloc_percpu(size + align + sizeof(void *), 1); | |
997 | cwqs = PTR_ALIGN(ptr, align); | |
998 | *(void **)per_cpu_ptr(cwqs + 1, 0) = ptr; | |
999 | #else | |
1000 | /* On SMP, percpu allocator can do it itself */ | |
1001 | cwqs = __alloc_percpu(size, align); | |
1002 | #endif | |
1003 | /* just in case, make sure it's actually aligned */ | |
1004 | BUG_ON(!IS_ALIGNED((unsigned long)cwqs, align)); | |
1005 | return cwqs; | |
1006 | } | |
1007 | ||
1008 | static void free_cwqs(struct cpu_workqueue_struct *cwqs) | |
1009 | { | |
1010 | #ifndef CONFIG_SMP | |
1011 | /* on UP, the pointer to free is stored right after the cwq */ | |
1012 | if (cwqs) | |
1013 | free_percpu(*(void **)per_cpu_ptr(cwqs + 1, 0)); | |
1014 | #else | |
1015 | free_percpu(cwqs); | |
1016 | #endif | |
1017 | } | |
1018 | ||
3af24433 ON |
1019 | static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
1020 | { | |
1021 | struct workqueue_struct *wq = cwq->wq; | |
3af24433 ON |
1022 | struct task_struct *p; |
1023 | ||
1537663f | 1024 | p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); |
3af24433 ON |
1025 | /* |
1026 | * Nobody can add the work_struct to this cwq, | |
1027 | * if (caller is __create_workqueue) | |
1028 | * nobody should see this wq | |
1029 | * else // caller is CPU_UP_PREPARE | |
1030 | * cpu is not on cpu_online_map | |
1031 | * so we can abort safely. | |
1032 | */ | |
1033 | if (IS_ERR(p)) | |
1034 | return PTR_ERR(p); | |
3af24433 | 1035 | cwq->thread = p; |
3af24433 ON |
1036 | |
1037 | return 0; | |
1038 | } | |
1039 | ||
06ba38a9 ON |
1040 | static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
1041 | { | |
1042 | struct task_struct *p = cwq->thread; | |
1043 | ||
1044 | if (p != NULL) { | |
1045 | if (cpu >= 0) | |
1046 | kthread_bind(p, cpu); | |
1047 | wake_up_process(p); | |
1048 | } | |
1049 | } | |
1050 | ||
4e6045f1 | 1051 | struct workqueue_struct *__create_workqueue_key(const char *name, |
97e37d7b | 1052 | unsigned int flags, |
eb13ba87 JB |
1053 | struct lock_class_key *key, |
1054 | const char *lock_name) | |
1da177e4 | 1055 | { |
1537663f | 1056 | bool singlethread = flags & WQ_SINGLE_THREAD; |
1da177e4 | 1057 | struct workqueue_struct *wq; |
3af24433 | 1058 | int err = 0, cpu; |
1da177e4 | 1059 | |
3af24433 ON |
1060 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
1061 | if (!wq) | |
4690c4ab | 1062 | goto err; |
3af24433 | 1063 | |
0f900049 | 1064 | wq->cpu_wq = alloc_cwqs(); |
4690c4ab TH |
1065 | if (!wq->cpu_wq) |
1066 | goto err; | |
3af24433 | 1067 | |
97e37d7b | 1068 | wq->flags = flags; |
3af24433 | 1069 | wq->name = name; |
eb13ba87 | 1070 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 1071 | INIT_LIST_HEAD(&wq->list); |
3af24433 | 1072 | |
1537663f TH |
1073 | cpu_maps_update_begin(); |
1074 | /* | |
1075 | * We must initialize cwqs for each possible cpu even if we | |
1076 | * are going to call destroy_workqueue() finally. Otherwise | |
1077 | * cpu_up() can hit the uninitialized cwq once we drop the | |
1078 | * lock. | |
1079 | */ | |
1080 | for_each_possible_cpu(cpu) { | |
1081 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
1082 | ||
0f900049 | 1083 | BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); |
1537663f TH |
1084 | cwq->wq = wq; |
1085 | cwq->cpu = cpu; | |
1086 | spin_lock_init(&cwq->lock); | |
1087 | INIT_LIST_HEAD(&cwq->worklist); | |
1088 | init_waitqueue_head(&cwq->more_work); | |
1089 | ||
1090 | if (err) | |
1091 | continue; | |
1092 | err = create_workqueue_thread(cwq, cpu); | |
1093 | if (cpu_online(cpu) && !singlethread) | |
06ba38a9 | 1094 | start_workqueue_thread(cwq, cpu); |
1537663f TH |
1095 | else |
1096 | start_workqueue_thread(cwq, -1); | |
3af24433 ON |
1097 | } |
1098 | ||
1537663f TH |
1099 | spin_lock(&workqueue_lock); |
1100 | list_add(&wq->list, &workqueues); | |
1101 | spin_unlock(&workqueue_lock); | |
1102 | ||
1103 | cpu_maps_update_done(); | |
1104 | ||
3af24433 ON |
1105 | if (err) { |
1106 | destroy_workqueue(wq); | |
1107 | wq = NULL; | |
1108 | } | |
1109 | return wq; | |
4690c4ab TH |
1110 | err: |
1111 | if (wq) { | |
0f900049 | 1112 | free_cwqs(wq->cpu_wq); |
4690c4ab TH |
1113 | kfree(wq); |
1114 | } | |
1115 | return NULL; | |
3af24433 | 1116 | } |
4e6045f1 | 1117 | EXPORT_SYMBOL_GPL(__create_workqueue_key); |
1da177e4 | 1118 | |
1e35eaa2 | 1119 | static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) |
3af24433 | 1120 | { |
14441960 | 1121 | /* |
3da1c84c ON |
1122 | * Our caller is either destroy_workqueue() or CPU_POST_DEAD, |
1123 | * cpu_add_remove_lock protects cwq->thread. | |
14441960 ON |
1124 | */ |
1125 | if (cwq->thread == NULL) | |
1126 | return; | |
3af24433 | 1127 | |
3295f0ef IM |
1128 | lock_map_acquire(&cwq->wq->lockdep_map); |
1129 | lock_map_release(&cwq->wq->lockdep_map); | |
4e6045f1 | 1130 | |
13c22168 | 1131 | flush_cpu_workqueue(cwq); |
14441960 | 1132 | /* |
3da1c84c | 1133 | * If the caller is CPU_POST_DEAD and cwq->worklist was not empty, |
13c22168 ON |
1134 | * a concurrent flush_workqueue() can insert a barrier after us. |
1135 | * However, in that case run_workqueue() won't return and check | |
1136 | * kthread_should_stop() until it flushes all work_struct's. | |
14441960 ON |
1137 | * When ->worklist becomes empty it is safe to exit because no |
1138 | * more work_structs can be queued on this cwq: flush_workqueue | |
1139 | * checks list_empty(), and a "normal" queue_work() can't use | |
1140 | * a dead CPU. | |
1141 | */ | |
14441960 ON |
1142 | kthread_stop(cwq->thread); |
1143 | cwq->thread = NULL; | |
3af24433 ON |
1144 | } |
1145 | ||
1146 | /** | |
1147 | * destroy_workqueue - safely terminate a workqueue | |
1148 | * @wq: target workqueue | |
1149 | * | |
1150 | * Safely destroy a workqueue. All work currently pending will be done first. | |
1151 | */ | |
1152 | void destroy_workqueue(struct workqueue_struct *wq) | |
1153 | { | |
b1f4ec17 | 1154 | int cpu; |
3af24433 | 1155 | |
3da1c84c | 1156 | cpu_maps_update_begin(); |
95402b38 | 1157 | spin_lock(&workqueue_lock); |
b1f4ec17 | 1158 | list_del(&wq->list); |
95402b38 | 1159 | spin_unlock(&workqueue_lock); |
1537663f | 1160 | cpu_maps_update_done(); |
3af24433 | 1161 | |
1537663f TH |
1162 | for_each_possible_cpu(cpu) |
1163 | cleanup_workqueue_thread(get_cwq(cpu, wq)); | |
9b41ea72 | 1164 | |
0f900049 | 1165 | free_cwqs(wq->cpu_wq); |
3af24433 ON |
1166 | kfree(wq); |
1167 | } | |
1168 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
1169 | ||
1170 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
1171 | unsigned long action, | |
1172 | void *hcpu) | |
1173 | { | |
1174 | unsigned int cpu = (unsigned long)hcpu; | |
1175 | struct cpu_workqueue_struct *cwq; | |
1176 | struct workqueue_struct *wq; | |
1177 | ||
8bb78442 RW |
1178 | action &= ~CPU_TASKS_FROZEN; |
1179 | ||
3af24433 | 1180 | list_for_each_entry(wq, &workqueues, list) { |
1537663f TH |
1181 | if (wq->flags & WQ_SINGLE_THREAD) |
1182 | continue; | |
3af24433 | 1183 | |
1537663f | 1184 | cwq = get_cwq(cpu, wq); |
3af24433 | 1185 | |
1537663f | 1186 | switch (action) { |
3da1c84c | 1187 | case CPU_POST_DEAD: |
1537663f TH |
1188 | lock_map_acquire(&cwq->wq->lockdep_map); |
1189 | lock_map_release(&cwq->wq->lockdep_map); | |
1190 | flush_cpu_workqueue(cwq); | |
3af24433 ON |
1191 | break; |
1192 | } | |
1da177e4 LT |
1193 | } |
1194 | ||
1537663f | 1195 | return notifier_from_errno(0); |
1da177e4 | 1196 | } |
1da177e4 | 1197 | |
2d3854a3 | 1198 | #ifdef CONFIG_SMP |
8ccad40d | 1199 | |
2d3854a3 | 1200 | struct work_for_cpu { |
6b44003e | 1201 | struct completion completion; |
2d3854a3 RR |
1202 | long (*fn)(void *); |
1203 | void *arg; | |
1204 | long ret; | |
1205 | }; | |
1206 | ||
6b44003e | 1207 | static int do_work_for_cpu(void *_wfc) |
2d3854a3 | 1208 | { |
6b44003e | 1209 | struct work_for_cpu *wfc = _wfc; |
2d3854a3 | 1210 | wfc->ret = wfc->fn(wfc->arg); |
6b44003e AM |
1211 | complete(&wfc->completion); |
1212 | return 0; | |
2d3854a3 RR |
1213 | } |
1214 | ||
1215 | /** | |
1216 | * work_on_cpu - run a function in user context on a particular cpu | |
1217 | * @cpu: the cpu to run on | |
1218 | * @fn: the function to run | |
1219 | * @arg: the function arg | |
1220 | * | |
31ad9081 RR |
1221 | * This will return the value @fn returns. |
1222 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
6b44003e | 1223 | * The caller must not hold any locks which would prevent @fn from completing. |
2d3854a3 RR |
1224 | */ |
1225 | long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) | |
1226 | { | |
6b44003e AM |
1227 | struct task_struct *sub_thread; |
1228 | struct work_for_cpu wfc = { | |
1229 | .completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion), | |
1230 | .fn = fn, | |
1231 | .arg = arg, | |
1232 | }; | |
1233 | ||
1234 | sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu"); | |
1235 | if (IS_ERR(sub_thread)) | |
1236 | return PTR_ERR(sub_thread); | |
1237 | kthread_bind(sub_thread, cpu); | |
1238 | wake_up_process(sub_thread); | |
1239 | wait_for_completion(&wfc.completion); | |
2d3854a3 RR |
1240 | return wfc.ret; |
1241 | } | |
1242 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
1243 | #endif /* CONFIG_SMP */ | |
1244 | ||
c12920d1 | 1245 | void __init init_workqueues(void) |
1da177e4 | 1246 | { |
e7577c50 | 1247 | singlethread_cpu = cpumask_first(cpu_possible_mask); |
1da177e4 LT |
1248 | hotcpu_notifier(workqueue_cpu_callback, 0); |
1249 | keventd_wq = create_workqueue("events"); | |
1250 | BUG_ON(!keventd_wq); | |
1251 | } |