Commit | Line | Data |
---|---|---|
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> |
c34056a3 | 36 | #include <linux/idr.h> |
1da177e4 | 37 | |
4690c4ab TH |
38 | /* |
39 | * Structure fields follow one of the following exclusion rules. | |
40 | * | |
41 | * I: Set during initialization and read-only afterwards. | |
42 | * | |
43 | * L: cwq->lock protected. Access with cwq->lock held. | |
44 | * | |
73f53c4a TH |
45 | * F: wq->flush_mutex protected. |
46 | * | |
4690c4ab TH |
47 | * W: workqueue_lock protected. |
48 | */ | |
49 | ||
c34056a3 TH |
50 | struct cpu_workqueue_struct; |
51 | ||
52 | struct worker { | |
53 | struct work_struct *current_work; /* L: work being processed */ | |
affee4b2 | 54 | struct list_head scheduled; /* L: scheduled works */ |
c34056a3 TH |
55 | struct task_struct *task; /* I: worker task */ |
56 | struct cpu_workqueue_struct *cwq; /* I: the associated cwq */ | |
57 | int id; /* I: worker id */ | |
58 | }; | |
59 | ||
1da177e4 | 60 | /* |
f756d5e2 | 61 | * The per-CPU workqueue (if single thread, we always use the first |
0f900049 TH |
62 | * possible cpu). The lower WORK_STRUCT_FLAG_BITS of |
63 | * work_struct->data are used for flags and thus cwqs need to be | |
64 | * aligned at two's power of the number of flag bits. | |
1da177e4 LT |
65 | */ |
66 | struct cpu_workqueue_struct { | |
67 | ||
68 | spinlock_t lock; | |
69 | ||
1da177e4 LT |
70 | struct list_head worklist; |
71 | wait_queue_head_t more_work; | |
1537663f | 72 | unsigned int cpu; |
c34056a3 | 73 | struct worker *worker; |
1da177e4 | 74 | |
4690c4ab | 75 | struct workqueue_struct *wq; /* I: the owning workqueue */ |
73f53c4a TH |
76 | int work_color; /* L: current color */ |
77 | int flush_color; /* L: flushing color */ | |
78 | int nr_in_flight[WORK_NR_COLORS]; | |
79 | /* L: nr of in_flight works */ | |
0f900049 | 80 | }; |
1da177e4 | 81 | |
73f53c4a TH |
82 | /* |
83 | * Structure used to wait for workqueue flush. | |
84 | */ | |
85 | struct wq_flusher { | |
86 | struct list_head list; /* F: list of flushers */ | |
87 | int flush_color; /* F: flush color waiting for */ | |
88 | struct completion done; /* flush completion */ | |
89 | }; | |
90 | ||
1da177e4 LT |
91 | /* |
92 | * The externally visible workqueue abstraction is an array of | |
93 | * per-CPU workqueues: | |
94 | */ | |
95 | struct workqueue_struct { | |
97e37d7b | 96 | unsigned int flags; /* I: WQ_* flags */ |
4690c4ab TH |
97 | struct cpu_workqueue_struct *cpu_wq; /* I: cwq's */ |
98 | struct list_head list; /* W: list of all workqueues */ | |
73f53c4a TH |
99 | |
100 | struct mutex flush_mutex; /* protects wq flushing */ | |
101 | int work_color; /* F: current work color */ | |
102 | int flush_color; /* F: current flush color */ | |
103 | atomic_t nr_cwqs_to_flush; /* flush in progress */ | |
104 | struct wq_flusher *first_flusher; /* F: first flusher */ | |
105 | struct list_head flusher_queue; /* F: flush waiters */ | |
106 | struct list_head flusher_overflow; /* F: flush overflow list */ | |
107 | ||
4690c4ab | 108 | const char *name; /* I: workqueue name */ |
4e6045f1 | 109 | #ifdef CONFIG_LOCKDEP |
4690c4ab | 110 | struct lockdep_map lockdep_map; |
4e6045f1 | 111 | #endif |
1da177e4 LT |
112 | }; |
113 | ||
dc186ad7 TG |
114 | #ifdef CONFIG_DEBUG_OBJECTS_WORK |
115 | ||
116 | static struct debug_obj_descr work_debug_descr; | |
117 | ||
118 | /* | |
119 | * fixup_init is called when: | |
120 | * - an active object is initialized | |
121 | */ | |
122 | static int work_fixup_init(void *addr, enum debug_obj_state state) | |
123 | { | |
124 | struct work_struct *work = addr; | |
125 | ||
126 | switch (state) { | |
127 | case ODEBUG_STATE_ACTIVE: | |
128 | cancel_work_sync(work); | |
129 | debug_object_init(work, &work_debug_descr); | |
130 | return 1; | |
131 | default: | |
132 | return 0; | |
133 | } | |
134 | } | |
135 | ||
136 | /* | |
137 | * fixup_activate is called when: | |
138 | * - an active object is activated | |
139 | * - an unknown object is activated (might be a statically initialized object) | |
140 | */ | |
141 | static int work_fixup_activate(void *addr, enum debug_obj_state state) | |
142 | { | |
143 | struct work_struct *work = addr; | |
144 | ||
145 | switch (state) { | |
146 | ||
147 | case ODEBUG_STATE_NOTAVAILABLE: | |
148 | /* | |
149 | * This is not really a fixup. The work struct was | |
150 | * statically initialized. We just make sure that it | |
151 | * is tracked in the object tracker. | |
152 | */ | |
22df02bb | 153 | if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) { |
dc186ad7 TG |
154 | debug_object_init(work, &work_debug_descr); |
155 | debug_object_activate(work, &work_debug_descr); | |
156 | return 0; | |
157 | } | |
158 | WARN_ON_ONCE(1); | |
159 | return 0; | |
160 | ||
161 | case ODEBUG_STATE_ACTIVE: | |
162 | WARN_ON(1); | |
163 | ||
164 | default: | |
165 | return 0; | |
166 | } | |
167 | } | |
168 | ||
169 | /* | |
170 | * fixup_free is called when: | |
171 | * - an active object is freed | |
172 | */ | |
173 | static int work_fixup_free(void *addr, enum debug_obj_state state) | |
174 | { | |
175 | struct work_struct *work = addr; | |
176 | ||
177 | switch (state) { | |
178 | case ODEBUG_STATE_ACTIVE: | |
179 | cancel_work_sync(work); | |
180 | debug_object_free(work, &work_debug_descr); | |
181 | return 1; | |
182 | default: | |
183 | return 0; | |
184 | } | |
185 | } | |
186 | ||
187 | static struct debug_obj_descr work_debug_descr = { | |
188 | .name = "work_struct", | |
189 | .fixup_init = work_fixup_init, | |
190 | .fixup_activate = work_fixup_activate, | |
191 | .fixup_free = work_fixup_free, | |
192 | }; | |
193 | ||
194 | static inline void debug_work_activate(struct work_struct *work) | |
195 | { | |
196 | debug_object_activate(work, &work_debug_descr); | |
197 | } | |
198 | ||
199 | static inline void debug_work_deactivate(struct work_struct *work) | |
200 | { | |
201 | debug_object_deactivate(work, &work_debug_descr); | |
202 | } | |
203 | ||
204 | void __init_work(struct work_struct *work, int onstack) | |
205 | { | |
206 | if (onstack) | |
207 | debug_object_init_on_stack(work, &work_debug_descr); | |
208 | else | |
209 | debug_object_init(work, &work_debug_descr); | |
210 | } | |
211 | EXPORT_SYMBOL_GPL(__init_work); | |
212 | ||
213 | void destroy_work_on_stack(struct work_struct *work) | |
214 | { | |
215 | debug_object_free(work, &work_debug_descr); | |
216 | } | |
217 | EXPORT_SYMBOL_GPL(destroy_work_on_stack); | |
218 | ||
219 | #else | |
220 | static inline void debug_work_activate(struct work_struct *work) { } | |
221 | static inline void debug_work_deactivate(struct work_struct *work) { } | |
222 | #endif | |
223 | ||
95402b38 GS |
224 | /* Serializes the accesses to the list of workqueues. */ |
225 | static DEFINE_SPINLOCK(workqueue_lock); | |
1da177e4 | 226 | static LIST_HEAD(workqueues); |
c34056a3 TH |
227 | static DEFINE_PER_CPU(struct ida, worker_ida); |
228 | ||
229 | static int worker_thread(void *__worker); | |
1da177e4 | 230 | |
3af24433 | 231 | static int singlethread_cpu __read_mostly; |
1da177e4 | 232 | |
1537663f TH |
233 | static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, |
234 | struct workqueue_struct *wq) | |
b1f4ec17 | 235 | { |
1537663f | 236 | return per_cpu_ptr(wq->cpu_wq, cpu); |
b1f4ec17 ON |
237 | } |
238 | ||
1537663f TH |
239 | static struct cpu_workqueue_struct *target_cwq(unsigned int cpu, |
240 | struct workqueue_struct *wq) | |
a848e3b6 | 241 | { |
1537663f | 242 | if (unlikely(wq->flags & WQ_SINGLE_THREAD)) |
a848e3b6 | 243 | cpu = singlethread_cpu; |
1537663f | 244 | return get_cwq(cpu, wq); |
a848e3b6 ON |
245 | } |
246 | ||
73f53c4a TH |
247 | static unsigned int work_color_to_flags(int color) |
248 | { | |
249 | return color << WORK_STRUCT_COLOR_SHIFT; | |
250 | } | |
251 | ||
252 | static int get_work_color(struct work_struct *work) | |
253 | { | |
254 | return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) & | |
255 | ((1 << WORK_STRUCT_COLOR_BITS) - 1); | |
256 | } | |
257 | ||
258 | static int work_next_color(int color) | |
259 | { | |
260 | return (color + 1) % WORK_NR_COLORS; | |
261 | } | |
262 | ||
4594bf15 DH |
263 | /* |
264 | * Set the workqueue on which a work item is to be run | |
265 | * - Must *only* be called if the pending flag is set | |
266 | */ | |
ed7c0fee | 267 | static inline void set_wq_data(struct work_struct *work, |
4690c4ab TH |
268 | struct cpu_workqueue_struct *cwq, |
269 | unsigned long extra_flags) | |
365970a1 | 270 | { |
4594bf15 | 271 | BUG_ON(!work_pending(work)); |
365970a1 | 272 | |
4690c4ab | 273 | atomic_long_set(&work->data, (unsigned long)cwq | work_static(work) | |
22df02bb | 274 | WORK_STRUCT_PENDING | extra_flags); |
365970a1 DH |
275 | } |
276 | ||
4d707b9f ON |
277 | /* |
278 | * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued. | |
279 | */ | |
280 | static inline void clear_wq_data(struct work_struct *work) | |
281 | { | |
4690c4ab | 282 | atomic_long_set(&work->data, work_static(work)); |
4d707b9f ON |
283 | } |
284 | ||
64166699 | 285 | static inline struct cpu_workqueue_struct *get_wq_data(struct work_struct *work) |
365970a1 | 286 | { |
64166699 TH |
287 | return (void *)(atomic_long_read(&work->data) & |
288 | WORK_STRUCT_WQ_DATA_MASK); | |
365970a1 DH |
289 | } |
290 | ||
4690c4ab TH |
291 | /** |
292 | * insert_work - insert a work into cwq | |
293 | * @cwq: cwq @work belongs to | |
294 | * @work: work to insert | |
295 | * @head: insertion point | |
296 | * @extra_flags: extra WORK_STRUCT_* flags to set | |
297 | * | |
298 | * Insert @work into @cwq after @head. | |
299 | * | |
300 | * CONTEXT: | |
301 | * spin_lock_irq(cwq->lock). | |
302 | */ | |
b89deed3 | 303 | static void insert_work(struct cpu_workqueue_struct *cwq, |
4690c4ab TH |
304 | struct work_struct *work, struct list_head *head, |
305 | unsigned int extra_flags) | |
b89deed3 | 306 | { |
4690c4ab TH |
307 | /* we own @work, set data and link */ |
308 | set_wq_data(work, cwq, extra_flags); | |
309 | ||
6e84d644 ON |
310 | /* |
311 | * Ensure that we get the right work->data if we see the | |
312 | * result of list_add() below, see try_to_grab_pending(). | |
313 | */ | |
314 | smp_wmb(); | |
4690c4ab | 315 | |
1a4d9b0a | 316 | list_add_tail(&work->entry, head); |
b89deed3 ON |
317 | wake_up(&cwq->more_work); |
318 | } | |
319 | ||
4690c4ab | 320 | static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, |
1da177e4 LT |
321 | struct work_struct *work) |
322 | { | |
1537663f | 323 | struct cpu_workqueue_struct *cwq = target_cwq(cpu, wq); |
1da177e4 LT |
324 | unsigned long flags; |
325 | ||
dc186ad7 | 326 | debug_work_activate(work); |
1da177e4 | 327 | spin_lock_irqsave(&cwq->lock, flags); |
4690c4ab | 328 | BUG_ON(!list_empty(&work->entry)); |
73f53c4a TH |
329 | cwq->nr_in_flight[cwq->work_color]++; |
330 | insert_work(cwq, work, &cwq->worklist, | |
331 | work_color_to_flags(cwq->work_color)); | |
1da177e4 LT |
332 | spin_unlock_irqrestore(&cwq->lock, flags); |
333 | } | |
334 | ||
0fcb78c2 REB |
335 | /** |
336 | * queue_work - queue work on a workqueue | |
337 | * @wq: workqueue to use | |
338 | * @work: work to queue | |
339 | * | |
057647fc | 340 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 | 341 | * |
00dfcaf7 ON |
342 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
343 | * it can be processed by another CPU. | |
1da177e4 | 344 | */ |
7ad5b3a5 | 345 | int queue_work(struct workqueue_struct *wq, struct work_struct *work) |
1da177e4 | 346 | { |
ef1ca236 ON |
347 | int ret; |
348 | ||
349 | ret = queue_work_on(get_cpu(), wq, work); | |
350 | put_cpu(); | |
351 | ||
1da177e4 LT |
352 | return ret; |
353 | } | |
ae90dd5d | 354 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 355 | |
c1a220e7 ZR |
356 | /** |
357 | * queue_work_on - queue work on specific cpu | |
358 | * @cpu: CPU number to execute work on | |
359 | * @wq: workqueue to use | |
360 | * @work: work to queue | |
361 | * | |
362 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
363 | * | |
364 | * We queue the work to a specific CPU, the caller must ensure it | |
365 | * can't go away. | |
366 | */ | |
367 | int | |
368 | queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) | |
369 | { | |
370 | int ret = 0; | |
371 | ||
22df02bb | 372 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
4690c4ab | 373 | __queue_work(cpu, wq, work); |
c1a220e7 ZR |
374 | ret = 1; |
375 | } | |
376 | return ret; | |
377 | } | |
378 | EXPORT_SYMBOL_GPL(queue_work_on); | |
379 | ||
6d141c3f | 380 | static void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 381 | { |
52bad64d | 382 | struct delayed_work *dwork = (struct delayed_work *)__data; |
ed7c0fee | 383 | struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
1da177e4 | 384 | |
4690c4ab | 385 | __queue_work(smp_processor_id(), cwq->wq, &dwork->work); |
1da177e4 LT |
386 | } |
387 | ||
0fcb78c2 REB |
388 | /** |
389 | * queue_delayed_work - queue work on a workqueue after delay | |
390 | * @wq: workqueue to use | |
af9997e4 | 391 | * @dwork: delayable work to queue |
0fcb78c2 REB |
392 | * @delay: number of jiffies to wait before queueing |
393 | * | |
057647fc | 394 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 395 | */ |
7ad5b3a5 | 396 | int queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 397 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 398 | { |
52bad64d | 399 | if (delay == 0) |
63bc0362 | 400 | return queue_work(wq, &dwork->work); |
1da177e4 | 401 | |
63bc0362 | 402 | return queue_delayed_work_on(-1, wq, dwork, delay); |
1da177e4 | 403 | } |
ae90dd5d | 404 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 405 | |
0fcb78c2 REB |
406 | /** |
407 | * queue_delayed_work_on - queue work on specific CPU after delay | |
408 | * @cpu: CPU number to execute work on | |
409 | * @wq: workqueue to use | |
af9997e4 | 410 | * @dwork: work to queue |
0fcb78c2 REB |
411 | * @delay: number of jiffies to wait before queueing |
412 | * | |
057647fc | 413 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 414 | */ |
7a6bc1cd | 415 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 416 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
417 | { |
418 | int ret = 0; | |
52bad64d DH |
419 | struct timer_list *timer = &dwork->timer; |
420 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 421 | |
22df02bb | 422 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
7a6bc1cd VP |
423 | BUG_ON(timer_pending(timer)); |
424 | BUG_ON(!list_empty(&work->entry)); | |
425 | ||
8a3e77cc AL |
426 | timer_stats_timer_set_start_info(&dwork->timer); |
427 | ||
ed7c0fee | 428 | /* This stores cwq for the moment, for the timer_fn */ |
1537663f | 429 | set_wq_data(work, target_cwq(raw_smp_processor_id(), wq), 0); |
7a6bc1cd | 430 | timer->expires = jiffies + delay; |
52bad64d | 431 | timer->data = (unsigned long)dwork; |
7a6bc1cd | 432 | timer->function = delayed_work_timer_fn; |
63bc0362 ON |
433 | |
434 | if (unlikely(cpu >= 0)) | |
435 | add_timer_on(timer, cpu); | |
436 | else | |
437 | add_timer(timer); | |
7a6bc1cd VP |
438 | ret = 1; |
439 | } | |
440 | return ret; | |
441 | } | |
ae90dd5d | 442 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 443 | |
c34056a3 TH |
444 | static struct worker *alloc_worker(void) |
445 | { | |
446 | struct worker *worker; | |
447 | ||
448 | worker = kzalloc(sizeof(*worker), GFP_KERNEL); | |
affee4b2 TH |
449 | if (worker) |
450 | INIT_LIST_HEAD(&worker->scheduled); | |
c34056a3 TH |
451 | return worker; |
452 | } | |
453 | ||
454 | /** | |
455 | * create_worker - create a new workqueue worker | |
456 | * @cwq: cwq the new worker will belong to | |
457 | * @bind: whether to set affinity to @cpu or not | |
458 | * | |
459 | * Create a new worker which is bound to @cwq. The returned worker | |
460 | * can be started by calling start_worker() or destroyed using | |
461 | * destroy_worker(). | |
462 | * | |
463 | * CONTEXT: | |
464 | * Might sleep. Does GFP_KERNEL allocations. | |
465 | * | |
466 | * RETURNS: | |
467 | * Pointer to the newly created worker. | |
468 | */ | |
469 | static struct worker *create_worker(struct cpu_workqueue_struct *cwq, bool bind) | |
470 | { | |
471 | int id = -1; | |
472 | struct worker *worker = NULL; | |
473 | ||
474 | spin_lock(&workqueue_lock); | |
475 | while (ida_get_new(&per_cpu(worker_ida, cwq->cpu), &id)) { | |
476 | spin_unlock(&workqueue_lock); | |
477 | if (!ida_pre_get(&per_cpu(worker_ida, cwq->cpu), GFP_KERNEL)) | |
478 | goto fail; | |
479 | spin_lock(&workqueue_lock); | |
480 | } | |
481 | spin_unlock(&workqueue_lock); | |
482 | ||
483 | worker = alloc_worker(); | |
484 | if (!worker) | |
485 | goto fail; | |
486 | ||
487 | worker->cwq = cwq; | |
488 | worker->id = id; | |
489 | ||
490 | worker->task = kthread_create(worker_thread, worker, "kworker/%u:%d", | |
491 | cwq->cpu, id); | |
492 | if (IS_ERR(worker->task)) | |
493 | goto fail; | |
494 | ||
495 | if (bind) | |
496 | kthread_bind(worker->task, cwq->cpu); | |
497 | ||
498 | return worker; | |
499 | fail: | |
500 | if (id >= 0) { | |
501 | spin_lock(&workqueue_lock); | |
502 | ida_remove(&per_cpu(worker_ida, cwq->cpu), id); | |
503 | spin_unlock(&workqueue_lock); | |
504 | } | |
505 | kfree(worker); | |
506 | return NULL; | |
507 | } | |
508 | ||
509 | /** | |
510 | * start_worker - start a newly created worker | |
511 | * @worker: worker to start | |
512 | * | |
513 | * Start @worker. | |
514 | * | |
515 | * CONTEXT: | |
516 | * spin_lock_irq(cwq->lock). | |
517 | */ | |
518 | static void start_worker(struct worker *worker) | |
519 | { | |
520 | wake_up_process(worker->task); | |
521 | } | |
522 | ||
523 | /** | |
524 | * destroy_worker - destroy a workqueue worker | |
525 | * @worker: worker to be destroyed | |
526 | * | |
527 | * Destroy @worker. | |
528 | */ | |
529 | static void destroy_worker(struct worker *worker) | |
530 | { | |
531 | int cpu = worker->cwq->cpu; | |
532 | int id = worker->id; | |
533 | ||
534 | /* sanity check frenzy */ | |
535 | BUG_ON(worker->current_work); | |
affee4b2 | 536 | BUG_ON(!list_empty(&worker->scheduled)); |
c34056a3 TH |
537 | |
538 | kthread_stop(worker->task); | |
539 | kfree(worker); | |
540 | ||
541 | spin_lock(&workqueue_lock); | |
542 | ida_remove(&per_cpu(worker_ida, cpu), id); | |
543 | spin_unlock(&workqueue_lock); | |
544 | } | |
545 | ||
affee4b2 TH |
546 | /** |
547 | * move_linked_works - move linked works to a list | |
548 | * @work: start of series of works to be scheduled | |
549 | * @head: target list to append @work to | |
550 | * @nextp: out paramter for nested worklist walking | |
551 | * | |
552 | * Schedule linked works starting from @work to @head. Work series to | |
553 | * be scheduled starts at @work and includes any consecutive work with | |
554 | * WORK_STRUCT_LINKED set in its predecessor. | |
555 | * | |
556 | * If @nextp is not NULL, it's updated to point to the next work of | |
557 | * the last scheduled work. This allows move_linked_works() to be | |
558 | * nested inside outer list_for_each_entry_safe(). | |
559 | * | |
560 | * CONTEXT: | |
561 | * spin_lock_irq(cwq->lock). | |
562 | */ | |
563 | static void move_linked_works(struct work_struct *work, struct list_head *head, | |
564 | struct work_struct **nextp) | |
565 | { | |
566 | struct work_struct *n; | |
567 | ||
568 | /* | |
569 | * Linked worklist will always end before the end of the list, | |
570 | * use NULL for list head. | |
571 | */ | |
572 | list_for_each_entry_safe_from(work, n, NULL, entry) { | |
573 | list_move_tail(&work->entry, head); | |
574 | if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) | |
575 | break; | |
576 | } | |
577 | ||
578 | /* | |
579 | * If we're already inside safe list traversal and have moved | |
580 | * multiple works to the scheduled queue, the next position | |
581 | * needs to be updated. | |
582 | */ | |
583 | if (nextp) | |
584 | *nextp = n; | |
585 | } | |
586 | ||
73f53c4a TH |
587 | /** |
588 | * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight | |
589 | * @cwq: cwq of interest | |
590 | * @color: color of work which left the queue | |
591 | * | |
592 | * A work either has completed or is removed from pending queue, | |
593 | * decrement nr_in_flight of its cwq and handle workqueue flushing. | |
594 | * | |
595 | * CONTEXT: | |
596 | * spin_lock_irq(cwq->lock). | |
597 | */ | |
598 | static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color) | |
599 | { | |
600 | /* ignore uncolored works */ | |
601 | if (color == WORK_NO_COLOR) | |
602 | return; | |
603 | ||
604 | cwq->nr_in_flight[color]--; | |
605 | ||
606 | /* is flush in progress and are we at the flushing tip? */ | |
607 | if (likely(cwq->flush_color != color)) | |
608 | return; | |
609 | ||
610 | /* are there still in-flight works? */ | |
611 | if (cwq->nr_in_flight[color]) | |
612 | return; | |
613 | ||
614 | /* this cwq is done, clear flush_color */ | |
615 | cwq->flush_color = -1; | |
616 | ||
617 | /* | |
618 | * If this was the last cwq, wake up the first flusher. It | |
619 | * will handle the rest. | |
620 | */ | |
621 | if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush)) | |
622 | complete(&cwq->wq->first_flusher->done); | |
623 | } | |
624 | ||
a62428c0 TH |
625 | /** |
626 | * process_one_work - process single work | |
c34056a3 | 627 | * @worker: self |
a62428c0 TH |
628 | * @work: work to process |
629 | * | |
630 | * Process @work. This function contains all the logics necessary to | |
631 | * process a single work including synchronization against and | |
632 | * interaction with other workers on the same cpu, queueing and | |
633 | * flushing. As long as context requirement is met, any worker can | |
634 | * call this function to process a work. | |
635 | * | |
636 | * CONTEXT: | |
637 | * spin_lock_irq(cwq->lock) which is released and regrabbed. | |
638 | */ | |
c34056a3 | 639 | static void process_one_work(struct worker *worker, struct work_struct *work) |
a62428c0 | 640 | { |
c34056a3 | 641 | struct cpu_workqueue_struct *cwq = worker->cwq; |
a62428c0 | 642 | work_func_t f = work->func; |
73f53c4a | 643 | int work_color; |
a62428c0 TH |
644 | #ifdef CONFIG_LOCKDEP |
645 | /* | |
646 | * It is permissible to free the struct work_struct from | |
647 | * inside the function that is called from it, this we need to | |
648 | * take into account for lockdep too. To avoid bogus "held | |
649 | * lock freed" warnings as well as problems when looking into | |
650 | * work->lockdep_map, make a copy and use that here. | |
651 | */ | |
652 | struct lockdep_map lockdep_map = work->lockdep_map; | |
653 | #endif | |
654 | /* claim and process */ | |
a62428c0 | 655 | debug_work_deactivate(work); |
c34056a3 | 656 | worker->current_work = work; |
73f53c4a | 657 | work_color = get_work_color(work); |
a62428c0 TH |
658 | list_del_init(&work->entry); |
659 | ||
660 | spin_unlock_irq(&cwq->lock); | |
661 | ||
662 | BUG_ON(get_wq_data(work) != cwq); | |
663 | work_clear_pending(work); | |
664 | lock_map_acquire(&cwq->wq->lockdep_map); | |
665 | lock_map_acquire(&lockdep_map); | |
666 | f(work); | |
667 | lock_map_release(&lockdep_map); | |
668 | lock_map_release(&cwq->wq->lockdep_map); | |
669 | ||
670 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { | |
671 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
672 | "%s/0x%08x/%d\n", | |
673 | current->comm, preempt_count(), task_pid_nr(current)); | |
674 | printk(KERN_ERR " last function: "); | |
675 | print_symbol("%s\n", (unsigned long)f); | |
676 | debug_show_held_locks(current); | |
677 | dump_stack(); | |
678 | } | |
679 | ||
680 | spin_lock_irq(&cwq->lock); | |
681 | ||
682 | /* we're done with it, release */ | |
c34056a3 | 683 | worker->current_work = NULL; |
73f53c4a | 684 | cwq_dec_nr_in_flight(cwq, work_color); |
a62428c0 TH |
685 | } |
686 | ||
affee4b2 TH |
687 | /** |
688 | * process_scheduled_works - process scheduled works | |
689 | * @worker: self | |
690 | * | |
691 | * Process all scheduled works. Please note that the scheduled list | |
692 | * may change while processing a work, so this function repeatedly | |
693 | * fetches a work from the top and executes it. | |
694 | * | |
695 | * CONTEXT: | |
696 | * spin_lock_irq(cwq->lock) which may be released and regrabbed | |
697 | * multiple times. | |
698 | */ | |
699 | static void process_scheduled_works(struct worker *worker) | |
1da177e4 | 700 | { |
affee4b2 TH |
701 | while (!list_empty(&worker->scheduled)) { |
702 | struct work_struct *work = list_first_entry(&worker->scheduled, | |
1da177e4 | 703 | struct work_struct, entry); |
c34056a3 | 704 | process_one_work(worker, work); |
1da177e4 | 705 | } |
1da177e4 LT |
706 | } |
707 | ||
4690c4ab TH |
708 | /** |
709 | * worker_thread - the worker thread function | |
c34056a3 | 710 | * @__worker: self |
4690c4ab TH |
711 | * |
712 | * The cwq worker thread function. | |
713 | */ | |
c34056a3 | 714 | static int worker_thread(void *__worker) |
1da177e4 | 715 | { |
c34056a3 TH |
716 | struct worker *worker = __worker; |
717 | struct cpu_workqueue_struct *cwq = worker->cwq; | |
3af24433 | 718 | DEFINE_WAIT(wait); |
1da177e4 | 719 | |
97e37d7b | 720 | if (cwq->wq->flags & WQ_FREEZEABLE) |
83144186 | 721 | set_freezable(); |
1da177e4 | 722 | |
3af24433 | 723 | for (;;) { |
3af24433 | 724 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
14441960 ON |
725 | if (!freezing(current) && |
726 | !kthread_should_stop() && | |
727 | list_empty(&cwq->worklist)) | |
1da177e4 | 728 | schedule(); |
3af24433 ON |
729 | finish_wait(&cwq->more_work, &wait); |
730 | ||
85f4186a ON |
731 | try_to_freeze(); |
732 | ||
14441960 | 733 | if (kthread_should_stop()) |
3af24433 | 734 | break; |
1da177e4 | 735 | |
c34056a3 | 736 | if (unlikely(!cpumask_equal(&worker->task->cpus_allowed, |
1537663f | 737 | get_cpu_mask(cwq->cpu)))) |
c34056a3 | 738 | set_cpus_allowed_ptr(worker->task, |
1537663f | 739 | get_cpu_mask(cwq->cpu)); |
affee4b2 TH |
740 | |
741 | spin_lock_irq(&cwq->lock); | |
742 | ||
743 | while (!list_empty(&cwq->worklist)) { | |
744 | struct work_struct *work = | |
745 | list_first_entry(&cwq->worklist, | |
746 | struct work_struct, entry); | |
747 | ||
748 | if (likely(!(*work_data_bits(work) & | |
749 | WORK_STRUCT_LINKED))) { | |
750 | /* optimization path, not strictly necessary */ | |
751 | process_one_work(worker, work); | |
752 | if (unlikely(!list_empty(&worker->scheduled))) | |
753 | process_scheduled_works(worker); | |
754 | } else { | |
755 | move_linked_works(work, &worker->scheduled, | |
756 | NULL); | |
757 | process_scheduled_works(worker); | |
758 | } | |
759 | } | |
760 | ||
761 | spin_unlock_irq(&cwq->lock); | |
1da177e4 | 762 | } |
3af24433 | 763 | |
1da177e4 LT |
764 | return 0; |
765 | } | |
766 | ||
fc2e4d70 ON |
767 | struct wq_barrier { |
768 | struct work_struct work; | |
769 | struct completion done; | |
770 | }; | |
771 | ||
772 | static void wq_barrier_func(struct work_struct *work) | |
773 | { | |
774 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
775 | complete(&barr->done); | |
776 | } | |
777 | ||
4690c4ab TH |
778 | /** |
779 | * insert_wq_barrier - insert a barrier work | |
780 | * @cwq: cwq to insert barrier into | |
781 | * @barr: wq_barrier to insert | |
affee4b2 TH |
782 | * @target: target work to attach @barr to |
783 | * @worker: worker currently executing @target, NULL if @target is not executing | |
4690c4ab | 784 | * |
affee4b2 TH |
785 | * @barr is linked to @target such that @barr is completed only after |
786 | * @target finishes execution. Please note that the ordering | |
787 | * guarantee is observed only with respect to @target and on the local | |
788 | * cpu. | |
789 | * | |
790 | * Currently, a queued barrier can't be canceled. This is because | |
791 | * try_to_grab_pending() can't determine whether the work to be | |
792 | * grabbed is at the head of the queue and thus can't clear LINKED | |
793 | * flag of the previous work while there must be a valid next work | |
794 | * after a work with LINKED flag set. | |
795 | * | |
796 | * Note that when @worker is non-NULL, @target may be modified | |
797 | * underneath us, so we can't reliably determine cwq from @target. | |
4690c4ab TH |
798 | * |
799 | * CONTEXT: | |
800 | * spin_lock_irq(cwq->lock). | |
801 | */ | |
83c22520 | 802 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
affee4b2 TH |
803 | struct wq_barrier *barr, |
804 | struct work_struct *target, struct worker *worker) | |
fc2e4d70 | 805 | { |
affee4b2 TH |
806 | struct list_head *head; |
807 | unsigned int linked = 0; | |
808 | ||
dc186ad7 TG |
809 | /* |
810 | * debugobject calls are safe here even with cwq->lock locked | |
811 | * as we know for sure that this will not trigger any of the | |
812 | * checks and call back into the fixup functions where we | |
813 | * might deadlock. | |
814 | */ | |
815 | INIT_WORK_ON_STACK(&barr->work, wq_barrier_func); | |
22df02bb | 816 | __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); |
fc2e4d70 | 817 | init_completion(&barr->done); |
83c22520 | 818 | |
affee4b2 TH |
819 | /* |
820 | * If @target is currently being executed, schedule the | |
821 | * barrier to the worker; otherwise, put it after @target. | |
822 | */ | |
823 | if (worker) | |
824 | head = worker->scheduled.next; | |
825 | else { | |
826 | unsigned long *bits = work_data_bits(target); | |
827 | ||
828 | head = target->entry.next; | |
829 | /* there can already be other linked works, inherit and set */ | |
830 | linked = *bits & WORK_STRUCT_LINKED; | |
831 | __set_bit(WORK_STRUCT_LINKED_BIT, bits); | |
832 | } | |
833 | ||
dc186ad7 | 834 | debug_work_activate(&barr->work); |
affee4b2 TH |
835 | insert_work(cwq, &barr->work, head, |
836 | work_color_to_flags(WORK_NO_COLOR) | linked); | |
fc2e4d70 ON |
837 | } |
838 | ||
73f53c4a TH |
839 | /** |
840 | * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing | |
841 | * @wq: workqueue being flushed | |
842 | * @flush_color: new flush color, < 0 for no-op | |
843 | * @work_color: new work color, < 0 for no-op | |
844 | * | |
845 | * Prepare cwqs for workqueue flushing. | |
846 | * | |
847 | * If @flush_color is non-negative, flush_color on all cwqs should be | |
848 | * -1. If no cwq has in-flight commands at the specified color, all | |
849 | * cwq->flush_color's stay at -1 and %false is returned. If any cwq | |
850 | * has in flight commands, its cwq->flush_color is set to | |
851 | * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq | |
852 | * wakeup logic is armed and %true is returned. | |
853 | * | |
854 | * The caller should have initialized @wq->first_flusher prior to | |
855 | * calling this function with non-negative @flush_color. If | |
856 | * @flush_color is negative, no flush color update is done and %false | |
857 | * is returned. | |
858 | * | |
859 | * If @work_color is non-negative, all cwqs should have the same | |
860 | * work_color which is previous to @work_color and all will be | |
861 | * advanced to @work_color. | |
862 | * | |
863 | * CONTEXT: | |
864 | * mutex_lock(wq->flush_mutex). | |
865 | * | |
866 | * RETURNS: | |
867 | * %true if @flush_color >= 0 and there's something to flush. %false | |
868 | * otherwise. | |
869 | */ | |
870 | static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, | |
871 | int flush_color, int work_color) | |
1da177e4 | 872 | { |
73f53c4a TH |
873 | bool wait = false; |
874 | unsigned int cpu; | |
1da177e4 | 875 | |
73f53c4a TH |
876 | if (flush_color >= 0) { |
877 | BUG_ON(atomic_read(&wq->nr_cwqs_to_flush)); | |
878 | atomic_set(&wq->nr_cwqs_to_flush, 1); | |
1da177e4 | 879 | } |
2355b70f | 880 | |
73f53c4a TH |
881 | for_each_possible_cpu(cpu) { |
882 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
883 | ||
884 | spin_lock_irq(&cwq->lock); | |
885 | ||
886 | if (flush_color >= 0) { | |
887 | BUG_ON(cwq->flush_color != -1); | |
888 | ||
889 | if (cwq->nr_in_flight[flush_color]) { | |
890 | cwq->flush_color = flush_color; | |
891 | atomic_inc(&wq->nr_cwqs_to_flush); | |
892 | wait = true; | |
893 | } | |
894 | } | |
895 | ||
896 | if (work_color >= 0) { | |
897 | BUG_ON(work_color != work_next_color(cwq->work_color)); | |
898 | cwq->work_color = work_color; | |
899 | } | |
900 | ||
901 | spin_unlock_irq(&cwq->lock); | |
dc186ad7 | 902 | } |
14441960 | 903 | |
73f53c4a TH |
904 | if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush)) |
905 | complete(&wq->first_flusher->done); | |
906 | ||
907 | return wait; | |
1da177e4 LT |
908 | } |
909 | ||
0fcb78c2 | 910 | /** |
1da177e4 | 911 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 912 | * @wq: workqueue to flush |
1da177e4 LT |
913 | * |
914 | * Forces execution of the workqueue and blocks until its completion. | |
915 | * This is typically used in driver shutdown handlers. | |
916 | * | |
fc2e4d70 ON |
917 | * We sleep until all works which were queued on entry have been handled, |
918 | * but we are not livelocked by new incoming ones. | |
1da177e4 | 919 | */ |
7ad5b3a5 | 920 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 921 | { |
73f53c4a TH |
922 | struct wq_flusher this_flusher = { |
923 | .list = LIST_HEAD_INIT(this_flusher.list), | |
924 | .flush_color = -1, | |
925 | .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done), | |
926 | }; | |
927 | int next_color; | |
1da177e4 | 928 | |
3295f0ef IM |
929 | lock_map_acquire(&wq->lockdep_map); |
930 | lock_map_release(&wq->lockdep_map); | |
73f53c4a TH |
931 | |
932 | mutex_lock(&wq->flush_mutex); | |
933 | ||
934 | /* | |
935 | * Start-to-wait phase | |
936 | */ | |
937 | next_color = work_next_color(wq->work_color); | |
938 | ||
939 | if (next_color != wq->flush_color) { | |
940 | /* | |
941 | * Color space is not full. The current work_color | |
942 | * becomes our flush_color and work_color is advanced | |
943 | * by one. | |
944 | */ | |
945 | BUG_ON(!list_empty(&wq->flusher_overflow)); | |
946 | this_flusher.flush_color = wq->work_color; | |
947 | wq->work_color = next_color; | |
948 | ||
949 | if (!wq->first_flusher) { | |
950 | /* no flush in progress, become the first flusher */ | |
951 | BUG_ON(wq->flush_color != this_flusher.flush_color); | |
952 | ||
953 | wq->first_flusher = &this_flusher; | |
954 | ||
955 | if (!flush_workqueue_prep_cwqs(wq, wq->flush_color, | |
956 | wq->work_color)) { | |
957 | /* nothing to flush, done */ | |
958 | wq->flush_color = next_color; | |
959 | wq->first_flusher = NULL; | |
960 | goto out_unlock; | |
961 | } | |
962 | } else { | |
963 | /* wait in queue */ | |
964 | BUG_ON(wq->flush_color == this_flusher.flush_color); | |
965 | list_add_tail(&this_flusher.list, &wq->flusher_queue); | |
966 | flush_workqueue_prep_cwqs(wq, -1, wq->work_color); | |
967 | } | |
968 | } else { | |
969 | /* | |
970 | * Oops, color space is full, wait on overflow queue. | |
971 | * The next flush completion will assign us | |
972 | * flush_color and transfer to flusher_queue. | |
973 | */ | |
974 | list_add_tail(&this_flusher.list, &wq->flusher_overflow); | |
975 | } | |
976 | ||
977 | mutex_unlock(&wq->flush_mutex); | |
978 | ||
979 | wait_for_completion(&this_flusher.done); | |
980 | ||
981 | /* | |
982 | * Wake-up-and-cascade phase | |
983 | * | |
984 | * First flushers are responsible for cascading flushes and | |
985 | * handling overflow. Non-first flushers can simply return. | |
986 | */ | |
987 | if (wq->first_flusher != &this_flusher) | |
988 | return; | |
989 | ||
990 | mutex_lock(&wq->flush_mutex); | |
991 | ||
992 | wq->first_flusher = NULL; | |
993 | ||
994 | BUG_ON(!list_empty(&this_flusher.list)); | |
995 | BUG_ON(wq->flush_color != this_flusher.flush_color); | |
996 | ||
997 | while (true) { | |
998 | struct wq_flusher *next, *tmp; | |
999 | ||
1000 | /* complete all the flushers sharing the current flush color */ | |
1001 | list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { | |
1002 | if (next->flush_color != wq->flush_color) | |
1003 | break; | |
1004 | list_del_init(&next->list); | |
1005 | complete(&next->done); | |
1006 | } | |
1007 | ||
1008 | BUG_ON(!list_empty(&wq->flusher_overflow) && | |
1009 | wq->flush_color != work_next_color(wq->work_color)); | |
1010 | ||
1011 | /* this flush_color is finished, advance by one */ | |
1012 | wq->flush_color = work_next_color(wq->flush_color); | |
1013 | ||
1014 | /* one color has been freed, handle overflow queue */ | |
1015 | if (!list_empty(&wq->flusher_overflow)) { | |
1016 | /* | |
1017 | * Assign the same color to all overflowed | |
1018 | * flushers, advance work_color and append to | |
1019 | * flusher_queue. This is the start-to-wait | |
1020 | * phase for these overflowed flushers. | |
1021 | */ | |
1022 | list_for_each_entry(tmp, &wq->flusher_overflow, list) | |
1023 | tmp->flush_color = wq->work_color; | |
1024 | ||
1025 | wq->work_color = work_next_color(wq->work_color); | |
1026 | ||
1027 | list_splice_tail_init(&wq->flusher_overflow, | |
1028 | &wq->flusher_queue); | |
1029 | flush_workqueue_prep_cwqs(wq, -1, wq->work_color); | |
1030 | } | |
1031 | ||
1032 | if (list_empty(&wq->flusher_queue)) { | |
1033 | BUG_ON(wq->flush_color != wq->work_color); | |
1034 | break; | |
1035 | } | |
1036 | ||
1037 | /* | |
1038 | * Need to flush more colors. Make the next flusher | |
1039 | * the new first flusher and arm cwqs. | |
1040 | */ | |
1041 | BUG_ON(wq->flush_color == wq->work_color); | |
1042 | BUG_ON(wq->flush_color != next->flush_color); | |
1043 | ||
1044 | list_del_init(&next->list); | |
1045 | wq->first_flusher = next; | |
1046 | ||
1047 | if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1)) | |
1048 | break; | |
1049 | ||
1050 | /* | |
1051 | * Meh... this color is already done, clear first | |
1052 | * flusher and repeat cascading. | |
1053 | */ | |
1054 | wq->first_flusher = NULL; | |
1055 | } | |
1056 | ||
1057 | out_unlock: | |
1058 | mutex_unlock(&wq->flush_mutex); | |
1da177e4 | 1059 | } |
ae90dd5d | 1060 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 1061 | |
db700897 ON |
1062 | /** |
1063 | * flush_work - block until a work_struct's callback has terminated | |
1064 | * @work: the work which is to be flushed | |
1065 | * | |
a67da70d ON |
1066 | * Returns false if @work has already terminated. |
1067 | * | |
db700897 ON |
1068 | * It is expected that, prior to calling flush_work(), the caller has |
1069 | * arranged for the work to not be requeued, otherwise it doesn't make | |
1070 | * sense to use this function. | |
1071 | */ | |
1072 | int flush_work(struct work_struct *work) | |
1073 | { | |
affee4b2 | 1074 | struct worker *worker = NULL; |
db700897 | 1075 | struct cpu_workqueue_struct *cwq; |
db700897 ON |
1076 | struct wq_barrier barr; |
1077 | ||
1078 | might_sleep(); | |
1079 | cwq = get_wq_data(work); | |
1080 | if (!cwq) | |
1081 | return 0; | |
1082 | ||
3295f0ef IM |
1083 | lock_map_acquire(&cwq->wq->lockdep_map); |
1084 | lock_map_release(&cwq->wq->lockdep_map); | |
a67da70d | 1085 | |
db700897 ON |
1086 | spin_lock_irq(&cwq->lock); |
1087 | if (!list_empty(&work->entry)) { | |
1088 | /* | |
1089 | * See the comment near try_to_grab_pending()->smp_rmb(). | |
1090 | * If it was re-queued under us we are not going to wait. | |
1091 | */ | |
1092 | smp_rmb(); | |
1093 | if (unlikely(cwq != get_wq_data(work))) | |
4690c4ab | 1094 | goto already_gone; |
db700897 | 1095 | } else { |
affee4b2 TH |
1096 | if (cwq->worker && cwq->worker->current_work == work) |
1097 | worker = cwq->worker; | |
1098 | if (!worker) | |
4690c4ab | 1099 | goto already_gone; |
db700897 | 1100 | } |
db700897 | 1101 | |
affee4b2 | 1102 | insert_wq_barrier(cwq, &barr, work, worker); |
4690c4ab | 1103 | spin_unlock_irq(&cwq->lock); |
db700897 | 1104 | wait_for_completion(&barr.done); |
dc186ad7 | 1105 | destroy_work_on_stack(&barr.work); |
db700897 | 1106 | return 1; |
4690c4ab TH |
1107 | already_gone: |
1108 | spin_unlock_irq(&cwq->lock); | |
1109 | return 0; | |
db700897 ON |
1110 | } |
1111 | EXPORT_SYMBOL_GPL(flush_work); | |
1112 | ||
6e84d644 | 1113 | /* |
1f1f642e | 1114 | * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, |
6e84d644 ON |
1115 | * so this work can't be re-armed in any way. |
1116 | */ | |
1117 | static int try_to_grab_pending(struct work_struct *work) | |
1118 | { | |
1119 | struct cpu_workqueue_struct *cwq; | |
1f1f642e | 1120 | int ret = -1; |
6e84d644 | 1121 | |
22df02bb | 1122 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) |
1f1f642e | 1123 | return 0; |
6e84d644 ON |
1124 | |
1125 | /* | |
1126 | * The queueing is in progress, or it is already queued. Try to | |
1127 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
1128 | */ | |
1129 | ||
1130 | cwq = get_wq_data(work); | |
1131 | if (!cwq) | |
1132 | return ret; | |
1133 | ||
1134 | spin_lock_irq(&cwq->lock); | |
1135 | if (!list_empty(&work->entry)) { | |
1136 | /* | |
1137 | * This work is queued, but perhaps we locked the wrong cwq. | |
1138 | * In that case we must see the new value after rmb(), see | |
1139 | * insert_work()->wmb(). | |
1140 | */ | |
1141 | smp_rmb(); | |
1142 | if (cwq == get_wq_data(work)) { | |
dc186ad7 | 1143 | debug_work_deactivate(work); |
6e84d644 | 1144 | list_del_init(&work->entry); |
73f53c4a | 1145 | cwq_dec_nr_in_flight(cwq, get_work_color(work)); |
6e84d644 ON |
1146 | ret = 1; |
1147 | } | |
1148 | } | |
1149 | spin_unlock_irq(&cwq->lock); | |
1150 | ||
1151 | return ret; | |
1152 | } | |
1153 | ||
1154 | static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | |
b89deed3 ON |
1155 | struct work_struct *work) |
1156 | { | |
1157 | struct wq_barrier barr; | |
affee4b2 | 1158 | struct worker *worker; |
b89deed3 ON |
1159 | |
1160 | spin_lock_irq(&cwq->lock); | |
affee4b2 TH |
1161 | |
1162 | worker = NULL; | |
c34056a3 | 1163 | if (unlikely(cwq->worker && cwq->worker->current_work == work)) { |
affee4b2 TH |
1164 | worker = cwq->worker; |
1165 | insert_wq_barrier(cwq, &barr, work, worker); | |
b89deed3 | 1166 | } |
affee4b2 | 1167 | |
b89deed3 ON |
1168 | spin_unlock_irq(&cwq->lock); |
1169 | ||
affee4b2 | 1170 | if (unlikely(worker)) { |
b89deed3 | 1171 | wait_for_completion(&barr.done); |
dc186ad7 TG |
1172 | destroy_work_on_stack(&barr.work); |
1173 | } | |
b89deed3 ON |
1174 | } |
1175 | ||
6e84d644 | 1176 | static void wait_on_work(struct work_struct *work) |
b89deed3 ON |
1177 | { |
1178 | struct cpu_workqueue_struct *cwq; | |
28e53bdd | 1179 | struct workqueue_struct *wq; |
b1f4ec17 | 1180 | int cpu; |
b89deed3 | 1181 | |
f293ea92 ON |
1182 | might_sleep(); |
1183 | ||
3295f0ef IM |
1184 | lock_map_acquire(&work->lockdep_map); |
1185 | lock_map_release(&work->lockdep_map); | |
4e6045f1 | 1186 | |
b89deed3 | 1187 | cwq = get_wq_data(work); |
b89deed3 | 1188 | if (!cwq) |
3af24433 | 1189 | return; |
b89deed3 | 1190 | |
28e53bdd | 1191 | wq = cwq->wq; |
28e53bdd | 1192 | |
1537663f | 1193 | for_each_possible_cpu(cpu) |
4690c4ab | 1194 | wait_on_cpu_work(get_cwq(cpu, wq), work); |
6e84d644 ON |
1195 | } |
1196 | ||
1f1f642e ON |
1197 | static int __cancel_work_timer(struct work_struct *work, |
1198 | struct timer_list* timer) | |
1199 | { | |
1200 | int ret; | |
1201 | ||
1202 | do { | |
1203 | ret = (timer && likely(del_timer(timer))); | |
1204 | if (!ret) | |
1205 | ret = try_to_grab_pending(work); | |
1206 | wait_on_work(work); | |
1207 | } while (unlikely(ret < 0)); | |
1208 | ||
4d707b9f | 1209 | clear_wq_data(work); |
1f1f642e ON |
1210 | return ret; |
1211 | } | |
1212 | ||
6e84d644 ON |
1213 | /** |
1214 | * cancel_work_sync - block until a work_struct's callback has terminated | |
1215 | * @work: the work which is to be flushed | |
1216 | * | |
1f1f642e ON |
1217 | * Returns true if @work was pending. |
1218 | * | |
6e84d644 ON |
1219 | * cancel_work_sync() will cancel the work if it is queued. If the work's |
1220 | * callback appears to be running, cancel_work_sync() will block until it | |
1221 | * has completed. | |
1222 | * | |
1223 | * It is possible to use this function if the work re-queues itself. It can | |
1224 | * cancel the work even if it migrates to another workqueue, however in that | |
1225 | * case it only guarantees that work->func() has completed on the last queued | |
1226 | * workqueue. | |
1227 | * | |
1228 | * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not | |
1229 | * pending, otherwise it goes into a busy-wait loop until the timer expires. | |
1230 | * | |
1231 | * The caller must ensure that workqueue_struct on which this work was last | |
1232 | * queued can't be destroyed before this function returns. | |
1233 | */ | |
1f1f642e | 1234 | int cancel_work_sync(struct work_struct *work) |
6e84d644 | 1235 | { |
1f1f642e | 1236 | return __cancel_work_timer(work, NULL); |
b89deed3 | 1237 | } |
28e53bdd | 1238 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 1239 | |
6e84d644 | 1240 | /** |
f5a421a4 | 1241 | * cancel_delayed_work_sync - reliably kill off a delayed work. |
6e84d644 ON |
1242 | * @dwork: the delayed work struct |
1243 | * | |
1f1f642e ON |
1244 | * Returns true if @dwork was pending. |
1245 | * | |
6e84d644 ON |
1246 | * It is possible to use this function if @dwork rearms itself via queue_work() |
1247 | * or queue_delayed_work(). See also the comment for cancel_work_sync(). | |
1248 | */ | |
1f1f642e | 1249 | int cancel_delayed_work_sync(struct delayed_work *dwork) |
6e84d644 | 1250 | { |
1f1f642e | 1251 | return __cancel_work_timer(&dwork->work, &dwork->timer); |
6e84d644 | 1252 | } |
f5a421a4 | 1253 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 1254 | |
6e84d644 | 1255 | static struct workqueue_struct *keventd_wq __read_mostly; |
1da177e4 | 1256 | |
0fcb78c2 REB |
1257 | /** |
1258 | * schedule_work - put work task in global workqueue | |
1259 | * @work: job to be done | |
1260 | * | |
5b0f437d BVA |
1261 | * Returns zero if @work was already on the kernel-global workqueue and |
1262 | * non-zero otherwise. | |
1263 | * | |
1264 | * This puts a job in the kernel-global workqueue if it was not already | |
1265 | * queued and leaves it in the same position on the kernel-global | |
1266 | * workqueue otherwise. | |
0fcb78c2 | 1267 | */ |
7ad5b3a5 | 1268 | int schedule_work(struct work_struct *work) |
1da177e4 LT |
1269 | { |
1270 | return queue_work(keventd_wq, work); | |
1271 | } | |
ae90dd5d | 1272 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 1273 | |
c1a220e7 ZR |
1274 | /* |
1275 | * schedule_work_on - put work task on a specific cpu | |
1276 | * @cpu: cpu to put the work task on | |
1277 | * @work: job to be done | |
1278 | * | |
1279 | * This puts a job on a specific cpu | |
1280 | */ | |
1281 | int schedule_work_on(int cpu, struct work_struct *work) | |
1282 | { | |
1283 | return queue_work_on(cpu, keventd_wq, work); | |
1284 | } | |
1285 | EXPORT_SYMBOL(schedule_work_on); | |
1286 | ||
0fcb78c2 REB |
1287 | /** |
1288 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
1289 | * @dwork: job to be done |
1290 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
1291 | * |
1292 | * After waiting for a given time this puts a job in the kernel-global | |
1293 | * workqueue. | |
1294 | */ | |
7ad5b3a5 | 1295 | int schedule_delayed_work(struct delayed_work *dwork, |
82f67cd9 | 1296 | unsigned long delay) |
1da177e4 | 1297 | { |
52bad64d | 1298 | return queue_delayed_work(keventd_wq, dwork, delay); |
1da177e4 | 1299 | } |
ae90dd5d | 1300 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 1301 | |
8c53e463 LT |
1302 | /** |
1303 | * flush_delayed_work - block until a dwork_struct's callback has terminated | |
1304 | * @dwork: the delayed work which is to be flushed | |
1305 | * | |
1306 | * Any timeout is cancelled, and any pending work is run immediately. | |
1307 | */ | |
1308 | void flush_delayed_work(struct delayed_work *dwork) | |
1309 | { | |
1310 | if (del_timer_sync(&dwork->timer)) { | |
4690c4ab TH |
1311 | __queue_work(get_cpu(), get_wq_data(&dwork->work)->wq, |
1312 | &dwork->work); | |
8c53e463 LT |
1313 | put_cpu(); |
1314 | } | |
1315 | flush_work(&dwork->work); | |
1316 | } | |
1317 | EXPORT_SYMBOL(flush_delayed_work); | |
1318 | ||
0fcb78c2 REB |
1319 | /** |
1320 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
1321 | * @cpu: cpu to use | |
52bad64d | 1322 | * @dwork: job to be done |
0fcb78c2 REB |
1323 | * @delay: number of jiffies to wait |
1324 | * | |
1325 | * After waiting for a given time this puts a job in the kernel-global | |
1326 | * workqueue on the specified CPU. | |
1327 | */ | |
1da177e4 | 1328 | int schedule_delayed_work_on(int cpu, |
52bad64d | 1329 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 1330 | { |
52bad64d | 1331 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
1da177e4 | 1332 | } |
ae90dd5d | 1333 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 1334 | |
b6136773 AM |
1335 | /** |
1336 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
1337 | * @func: the function to call | |
b6136773 AM |
1338 | * |
1339 | * Returns zero on success. | |
1340 | * Returns -ve errno on failure. | |
1341 | * | |
b6136773 AM |
1342 | * schedule_on_each_cpu() is very slow. |
1343 | */ | |
65f27f38 | 1344 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
1345 | { |
1346 | int cpu; | |
65a64464 | 1347 | int orig = -1; |
b6136773 | 1348 | struct work_struct *works; |
15316ba8 | 1349 | |
b6136773 AM |
1350 | works = alloc_percpu(struct work_struct); |
1351 | if (!works) | |
15316ba8 | 1352 | return -ENOMEM; |
b6136773 | 1353 | |
93981800 TH |
1354 | get_online_cpus(); |
1355 | ||
65a64464 | 1356 | /* |
93981800 TH |
1357 | * When running in keventd don't schedule a work item on |
1358 | * itself. Can just call directly because the work queue is | |
1359 | * already bound. This also is faster. | |
65a64464 | 1360 | */ |
93981800 | 1361 | if (current_is_keventd()) |
65a64464 | 1362 | orig = raw_smp_processor_id(); |
65a64464 | 1363 | |
15316ba8 | 1364 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
1365 | struct work_struct *work = per_cpu_ptr(works, cpu); |
1366 | ||
1367 | INIT_WORK(work, func); | |
65a64464 | 1368 | if (cpu != orig) |
93981800 | 1369 | schedule_work_on(cpu, work); |
65a64464 | 1370 | } |
93981800 TH |
1371 | if (orig >= 0) |
1372 | func(per_cpu_ptr(works, orig)); | |
1373 | ||
1374 | for_each_online_cpu(cpu) | |
1375 | flush_work(per_cpu_ptr(works, cpu)); | |
1376 | ||
95402b38 | 1377 | put_online_cpus(); |
b6136773 | 1378 | free_percpu(works); |
15316ba8 CL |
1379 | return 0; |
1380 | } | |
1381 | ||
eef6a7d5 AS |
1382 | /** |
1383 | * flush_scheduled_work - ensure that any scheduled work has run to completion. | |
1384 | * | |
1385 | * Forces execution of the kernel-global workqueue and blocks until its | |
1386 | * completion. | |
1387 | * | |
1388 | * Think twice before calling this function! It's very easy to get into | |
1389 | * trouble if you don't take great care. Either of the following situations | |
1390 | * will lead to deadlock: | |
1391 | * | |
1392 | * One of the work items currently on the workqueue needs to acquire | |
1393 | * a lock held by your code or its caller. | |
1394 | * | |
1395 | * Your code is running in the context of a work routine. | |
1396 | * | |
1397 | * They will be detected by lockdep when they occur, but the first might not | |
1398 | * occur very often. It depends on what work items are on the workqueue and | |
1399 | * what locks they need, which you have no control over. | |
1400 | * | |
1401 | * In most situations flushing the entire workqueue is overkill; you merely | |
1402 | * need to know that a particular work item isn't queued and isn't running. | |
1403 | * In such cases you should use cancel_delayed_work_sync() or | |
1404 | * cancel_work_sync() instead. | |
1405 | */ | |
1da177e4 LT |
1406 | void flush_scheduled_work(void) |
1407 | { | |
1408 | flush_workqueue(keventd_wq); | |
1409 | } | |
ae90dd5d | 1410 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 1411 | |
1fa44eca JB |
1412 | /** |
1413 | * execute_in_process_context - reliably execute the routine with user context | |
1414 | * @fn: the function to execute | |
1fa44eca JB |
1415 | * @ew: guaranteed storage for the execute work structure (must |
1416 | * be available when the work executes) | |
1417 | * | |
1418 | * Executes the function immediately if process context is available, | |
1419 | * otherwise schedules the function for delayed execution. | |
1420 | * | |
1421 | * Returns: 0 - function was executed | |
1422 | * 1 - function was scheduled for execution | |
1423 | */ | |
65f27f38 | 1424 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
1425 | { |
1426 | if (!in_interrupt()) { | |
65f27f38 | 1427 | fn(&ew->work); |
1fa44eca JB |
1428 | return 0; |
1429 | } | |
1430 | ||
65f27f38 | 1431 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
1432 | schedule_work(&ew->work); |
1433 | ||
1434 | return 1; | |
1435 | } | |
1436 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
1437 | ||
1da177e4 LT |
1438 | int keventd_up(void) |
1439 | { | |
1440 | return keventd_wq != NULL; | |
1441 | } | |
1442 | ||
1443 | int current_is_keventd(void) | |
1444 | { | |
1445 | struct cpu_workqueue_struct *cwq; | |
d243769d | 1446 | int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ |
1da177e4 LT |
1447 | int ret = 0; |
1448 | ||
1449 | BUG_ON(!keventd_wq); | |
1450 | ||
1537663f | 1451 | cwq = get_cwq(cpu, keventd_wq); |
c34056a3 | 1452 | if (current == cwq->worker->task) |
1da177e4 LT |
1453 | ret = 1; |
1454 | ||
1455 | return ret; | |
1456 | ||
1457 | } | |
1458 | ||
0f900049 TH |
1459 | static struct cpu_workqueue_struct *alloc_cwqs(void) |
1460 | { | |
1461 | /* | |
1462 | * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. | |
1463 | * Make sure that the alignment isn't lower than that of | |
1464 | * unsigned long long. | |
1465 | */ | |
1466 | const size_t size = sizeof(struct cpu_workqueue_struct); | |
1467 | const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, | |
1468 | __alignof__(unsigned long long)); | |
1469 | struct cpu_workqueue_struct *cwqs; | |
1470 | #ifndef CONFIG_SMP | |
1471 | void *ptr; | |
1472 | ||
1473 | /* | |
1474 | * On UP, percpu allocator doesn't honor alignment parameter | |
1475 | * and simply uses arch-dependent default. Allocate enough | |
1476 | * room to align cwq and put an extra pointer at the end | |
1477 | * pointing back to the originally allocated pointer which | |
1478 | * will be used for free. | |
1479 | * | |
1480 | * FIXME: This really belongs to UP percpu code. Update UP | |
1481 | * percpu code to honor alignment and remove this ugliness. | |
1482 | */ | |
1483 | ptr = __alloc_percpu(size + align + sizeof(void *), 1); | |
1484 | cwqs = PTR_ALIGN(ptr, align); | |
1485 | *(void **)per_cpu_ptr(cwqs + 1, 0) = ptr; | |
1486 | #else | |
1487 | /* On SMP, percpu allocator can do it itself */ | |
1488 | cwqs = __alloc_percpu(size, align); | |
1489 | #endif | |
1490 | /* just in case, make sure it's actually aligned */ | |
1491 | BUG_ON(!IS_ALIGNED((unsigned long)cwqs, align)); | |
1492 | return cwqs; | |
1493 | } | |
1494 | ||
1495 | static void free_cwqs(struct cpu_workqueue_struct *cwqs) | |
1496 | { | |
1497 | #ifndef CONFIG_SMP | |
1498 | /* on UP, the pointer to free is stored right after the cwq */ | |
1499 | if (cwqs) | |
1500 | free_percpu(*(void **)per_cpu_ptr(cwqs + 1, 0)); | |
1501 | #else | |
1502 | free_percpu(cwqs); | |
1503 | #endif | |
1504 | } | |
1505 | ||
4e6045f1 | 1506 | struct workqueue_struct *__create_workqueue_key(const char *name, |
97e37d7b | 1507 | unsigned int flags, |
eb13ba87 JB |
1508 | struct lock_class_key *key, |
1509 | const char *lock_name) | |
1da177e4 | 1510 | { |
1537663f | 1511 | bool singlethread = flags & WQ_SINGLE_THREAD; |
1da177e4 | 1512 | struct workqueue_struct *wq; |
c34056a3 TH |
1513 | bool failed = false; |
1514 | unsigned int cpu; | |
1da177e4 | 1515 | |
3af24433 ON |
1516 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
1517 | if (!wq) | |
4690c4ab | 1518 | goto err; |
3af24433 | 1519 | |
0f900049 | 1520 | wq->cpu_wq = alloc_cwqs(); |
4690c4ab TH |
1521 | if (!wq->cpu_wq) |
1522 | goto err; | |
3af24433 | 1523 | |
97e37d7b | 1524 | wq->flags = flags; |
73f53c4a TH |
1525 | mutex_init(&wq->flush_mutex); |
1526 | atomic_set(&wq->nr_cwqs_to_flush, 0); | |
1527 | INIT_LIST_HEAD(&wq->flusher_queue); | |
1528 | INIT_LIST_HEAD(&wq->flusher_overflow); | |
3af24433 | 1529 | wq->name = name; |
eb13ba87 | 1530 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 1531 | INIT_LIST_HEAD(&wq->list); |
3af24433 | 1532 | |
1537663f TH |
1533 | cpu_maps_update_begin(); |
1534 | /* | |
1535 | * We must initialize cwqs for each possible cpu even if we | |
1536 | * are going to call destroy_workqueue() finally. Otherwise | |
1537 | * cpu_up() can hit the uninitialized cwq once we drop the | |
1538 | * lock. | |
1539 | */ | |
1540 | for_each_possible_cpu(cpu) { | |
1541 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
1542 | ||
0f900049 | 1543 | BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); |
1537663f | 1544 | cwq->cpu = cpu; |
c34056a3 | 1545 | cwq->wq = wq; |
73f53c4a | 1546 | cwq->flush_color = -1; |
1537663f TH |
1547 | spin_lock_init(&cwq->lock); |
1548 | INIT_LIST_HEAD(&cwq->worklist); | |
1549 | init_waitqueue_head(&cwq->more_work); | |
1550 | ||
c34056a3 | 1551 | if (failed) |
1537663f | 1552 | continue; |
c34056a3 TH |
1553 | cwq->worker = create_worker(cwq, |
1554 | cpu_online(cpu) && !singlethread); | |
1555 | if (cwq->worker) | |
1556 | start_worker(cwq->worker); | |
1537663f | 1557 | else |
c34056a3 | 1558 | failed = true; |
3af24433 ON |
1559 | } |
1560 | ||
1537663f TH |
1561 | spin_lock(&workqueue_lock); |
1562 | list_add(&wq->list, &workqueues); | |
1563 | spin_unlock(&workqueue_lock); | |
1564 | ||
1565 | cpu_maps_update_done(); | |
1566 | ||
c34056a3 | 1567 | if (failed) { |
3af24433 ON |
1568 | destroy_workqueue(wq); |
1569 | wq = NULL; | |
1570 | } | |
1571 | return wq; | |
4690c4ab TH |
1572 | err: |
1573 | if (wq) { | |
0f900049 | 1574 | free_cwqs(wq->cpu_wq); |
4690c4ab TH |
1575 | kfree(wq); |
1576 | } | |
1577 | return NULL; | |
3af24433 | 1578 | } |
4e6045f1 | 1579 | EXPORT_SYMBOL_GPL(__create_workqueue_key); |
1da177e4 | 1580 | |
3af24433 ON |
1581 | /** |
1582 | * destroy_workqueue - safely terminate a workqueue | |
1583 | * @wq: target workqueue | |
1584 | * | |
1585 | * Safely destroy a workqueue. All work currently pending will be done first. | |
1586 | */ | |
1587 | void destroy_workqueue(struct workqueue_struct *wq) | |
1588 | { | |
b1f4ec17 | 1589 | int cpu; |
3af24433 | 1590 | |
3da1c84c | 1591 | cpu_maps_update_begin(); |
95402b38 | 1592 | spin_lock(&workqueue_lock); |
b1f4ec17 | 1593 | list_del(&wq->list); |
95402b38 | 1594 | spin_unlock(&workqueue_lock); |
1537663f | 1595 | cpu_maps_update_done(); |
3af24433 | 1596 | |
73f53c4a TH |
1597 | flush_workqueue(wq); |
1598 | ||
1599 | for_each_possible_cpu(cpu) { | |
1600 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
1601 | int i; | |
1602 | ||
c34056a3 TH |
1603 | if (cwq->worker) { |
1604 | destroy_worker(cwq->worker); | |
1605 | cwq->worker = NULL; | |
73f53c4a TH |
1606 | } |
1607 | ||
1608 | for (i = 0; i < WORK_NR_COLORS; i++) | |
1609 | BUG_ON(cwq->nr_in_flight[i]); | |
1610 | } | |
9b41ea72 | 1611 | |
0f900049 | 1612 | free_cwqs(wq->cpu_wq); |
3af24433 ON |
1613 | kfree(wq); |
1614 | } | |
1615 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
1616 | ||
1617 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | |
1618 | unsigned long action, | |
1619 | void *hcpu) | |
1620 | { | |
1621 | unsigned int cpu = (unsigned long)hcpu; | |
1622 | struct cpu_workqueue_struct *cwq; | |
1623 | struct workqueue_struct *wq; | |
1624 | ||
8bb78442 RW |
1625 | action &= ~CPU_TASKS_FROZEN; |
1626 | ||
3af24433 | 1627 | list_for_each_entry(wq, &workqueues, list) { |
1537663f TH |
1628 | if (wq->flags & WQ_SINGLE_THREAD) |
1629 | continue; | |
3af24433 | 1630 | |
1537663f | 1631 | cwq = get_cwq(cpu, wq); |
3af24433 | 1632 | |
1537663f | 1633 | switch (action) { |
3da1c84c | 1634 | case CPU_POST_DEAD: |
73f53c4a | 1635 | flush_workqueue(wq); |
3af24433 ON |
1636 | break; |
1637 | } | |
1da177e4 LT |
1638 | } |
1639 | ||
1537663f | 1640 | return notifier_from_errno(0); |
1da177e4 | 1641 | } |
1da177e4 | 1642 | |
2d3854a3 | 1643 | #ifdef CONFIG_SMP |
8ccad40d | 1644 | |
2d3854a3 | 1645 | struct work_for_cpu { |
6b44003e | 1646 | struct completion completion; |
2d3854a3 RR |
1647 | long (*fn)(void *); |
1648 | void *arg; | |
1649 | long ret; | |
1650 | }; | |
1651 | ||
6b44003e | 1652 | static int do_work_for_cpu(void *_wfc) |
2d3854a3 | 1653 | { |
6b44003e | 1654 | struct work_for_cpu *wfc = _wfc; |
2d3854a3 | 1655 | wfc->ret = wfc->fn(wfc->arg); |
6b44003e AM |
1656 | complete(&wfc->completion); |
1657 | return 0; | |
2d3854a3 RR |
1658 | } |
1659 | ||
1660 | /** | |
1661 | * work_on_cpu - run a function in user context on a particular cpu | |
1662 | * @cpu: the cpu to run on | |
1663 | * @fn: the function to run | |
1664 | * @arg: the function arg | |
1665 | * | |
31ad9081 RR |
1666 | * This will return the value @fn returns. |
1667 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
6b44003e | 1668 | * The caller must not hold any locks which would prevent @fn from completing. |
2d3854a3 RR |
1669 | */ |
1670 | long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) | |
1671 | { | |
6b44003e AM |
1672 | struct task_struct *sub_thread; |
1673 | struct work_for_cpu wfc = { | |
1674 | .completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion), | |
1675 | .fn = fn, | |
1676 | .arg = arg, | |
1677 | }; | |
1678 | ||
1679 | sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu"); | |
1680 | if (IS_ERR(sub_thread)) | |
1681 | return PTR_ERR(sub_thread); | |
1682 | kthread_bind(sub_thread, cpu); | |
1683 | wake_up_process(sub_thread); | |
1684 | wait_for_completion(&wfc.completion); | |
2d3854a3 RR |
1685 | return wfc.ret; |
1686 | } | |
1687 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
1688 | #endif /* CONFIG_SMP */ | |
1689 | ||
c12920d1 | 1690 | void __init init_workqueues(void) |
1da177e4 | 1691 | { |
c34056a3 TH |
1692 | unsigned int cpu; |
1693 | ||
1694 | for_each_possible_cpu(cpu) | |
1695 | ida_init(&per_cpu(worker_ida, cpu)); | |
1696 | ||
e7577c50 | 1697 | singlethread_cpu = cpumask_first(cpu_possible_mask); |
1da177e4 LT |
1698 | hotcpu_notifier(workqueue_cpu_callback, 0); |
1699 | keventd_wq = create_workqueue("events"); | |
1700 | BUG_ON(!keventd_wq); | |
1701 | } |