1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_WAIT_H
3 #define _LINUX_WAIT_H
4 /*
5 * Linux wait queue related types and methods
6 */
7 #include <linux/list.h>
8 #include <linux/stddef.h>
9 #include <linux/spinlock.h>
10
11 #include <asm/current.h>
12 #include <uapi/linux/wait.h>
13
14 typedef struct wait_queue_entry wait_queue_entry_t;
15
16 typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
17 int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
18
19 /* wait_queue_entry::flags */
20 #define WQ_FLAG_EXCLUSIVE 0x01
21 #define WQ_FLAG_WOKEN 0x02
22 #define WQ_FLAG_BOOKMARK 0x04
23
24 /*
25 * A single wait-queue entry structure:
26 */
27 struct wait_queue_entry {
28 unsigned int flags;
29 void *private;
30 wait_queue_func_t func;
31 struct list_head entry;
32 };
33
34 struct wait_queue_head {
35 spinlock_t lock;
36 struct list_head head;
37 };
38 typedef struct wait_queue_head wait_queue_head_t;
39
40 struct task_struct;
41
42 /*
43 * Macros for declaration and initialisaton of the datatypes
44 */
45
46 #define __WAITQUEUE_INITIALIZER(name, tsk) { \
47 .private = tsk, \
48 .func = default_wake_function, \
49 .entry = { NULL, NULL } }
50
51 #define DECLARE_WAITQUEUE(name, tsk) \
52 struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk)
53
54 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
55 .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
56 .head = { &(name).head, &(name).head } }
57
58 #define DECLARE_WAIT_QUEUE_HEAD(name) \
59 struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
60
61 extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
62
63 #define init_waitqueue_head(wq_head) \
64 do { \
65 static struct lock_class_key __key; \
66 \
67 __init_waitqueue_head((wq_head), #wq_head, &__key); \
68 } while (0)
69
70 #ifdef CONFIG_LOCKDEP
71 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
72 ({ init_waitqueue_head(&name); name; })
73 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
74 struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
75 #else
76 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
77 #endif
78
79 static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p)
80 {
81 wq_entry->flags = 0;
82 wq_entry->private = p;
83 wq_entry->func = default_wake_function;
84 }
85
86 static inline void
87 init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func)
88 {
89 wq_entry->flags = 0;
90 wq_entry->private = NULL;
91 wq_entry->func = func;
92 }
93
94 /**
95 * waitqueue_active -- locklessly test for waiters on the queue
96 * @wq_head: the waitqueue to test for waiters
97 *
98 * returns true if the wait list is not empty
99 *
100 * NOTE: this function is lockless and requires care, incorrect usage _will_
101 * lead to sporadic and non-obvious failure.
102 *
103 * Use either while holding wait_queue_head::lock or when used for wakeups
104 * with an extra smp_mb() like::
105 *
106 * CPU0 - waker CPU1 - waiter
107 *
108 * for (;;) {
109 * @cond = true; prepare_to_wait(&wq_head, &wait, state);
110 * smp_mb(); // smp_mb() from set_current_state()
111 * if (waitqueue_active(wq_head)) if (@cond)
112 * wake_up(wq_head); break;
113 * schedule();
114 * }
115 * finish_wait(&wq_head, &wait);
116 *
117 * Because without the explicit smp_mb() it's possible for the
118 * waitqueue_active() load to get hoisted over the @cond store such that we'll
119 * observe an empty wait list while the waiter might not observe @cond.
120 *
121 * Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
122 * which (when the lock is uncontended) are of roughly equal cost.
123 */
124 static inline int waitqueue_active(struct wait_queue_head *wq_head)
125 {
126 return !list_empty(&wq_head->head);
127 }
128
129 /**
130 * wq_has_single_sleeper - check if there is only one sleeper
131 * @wq_head: wait queue head
132 *
133 * Returns true of wq_head has only one sleeper on the list.
134 *
135 * Please refer to the comment for waitqueue_active.
136 */
137 static inline bool wq_has_single_sleeper(struct wait_queue_head *wq_head)
138 {
139 return list_is_singular(&wq_head->head);
140 }
141
142 /**
143 * wq_has_sleeper - check if there are any waiting processes
144 * @wq_head: wait queue head
145 *
146 * Returns true if wq_head has waiting processes
147 *
148 * Please refer to the comment for waitqueue_active.
149 */
150 static inline bool wq_has_sleeper(struct wait_queue_head *wq_head)
151 {
152 /*
153 * We need to be sure we are in sync with the
154 * add_wait_queue modifications to the wait queue.
155 *
156 * This memory barrier should be paired with one on the
157 * waiting side.
158 */
159 smp_mb();
160 return waitqueue_active(wq_head);
161 }
162
163 extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
164 extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
165 extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
166
167 static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
168 {
169 list_add(&wq_entry->entry, &wq_head->head);
170 }
171
172 /*
173 * Used for wake-one threads:
174 */
175 static inline void
176 __add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
177 {
178 wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
179 __add_wait_queue(wq_head, wq_entry);
180 }
181
182 static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
183 {
184 list_add_tail(&wq_entry->entry, &wq_head->head);
185 }
186
187 static inline void
188 __add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
189 {
190 wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
191 __add_wait_queue_entry_tail(wq_head, wq_entry);
192 }
193
194 static inline void
195 __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
196 {
197 list_del(&wq_entry->entry);
198 }
199
200 void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
201 void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
202 void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
203 unsigned int mode, void *key, wait_queue_entry_t *bookmark);
204 void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
205 void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
206 void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr);
207
208 #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
209 #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
210 #define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
211 #define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1)
212 #define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0)
213
214 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
215 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
216 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
217 #define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
218
219 /*
220 * Wakeup macros to be used to report events to the targets.
221 */
222 #define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m))
223 #define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m))
224 #define wake_up_poll(x, m) \
225 __wake_up(x, TASK_NORMAL, 1, poll_to_key(m))
226 #define wake_up_locked_poll(x, m) \
227 __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m))
228 #define wake_up_interruptible_poll(x, m) \
229 __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m))
230 #define wake_up_interruptible_sync_poll(x, m) \
231 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, poll_to_key(m))
232
233 #define ___wait_cond_timeout(condition) \
234 ({ \
235 bool __cond = (condition); \
236 if (__cond && !__ret) \
237 __ret = 1; \
238 __cond || !__ret; \
239 })
240
241 #define ___wait_is_interruptible(state) \
242 (!__builtin_constant_p(state) || \
243 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \
244
245 extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
246
247 /*
248 * The below macro ___wait_event() has an explicit shadow of the __ret
249 * variable when used from the wait_event_*() macros.
250 *
251 * This is so that both can use the ___wait_cond_timeout() construct
252 * to wrap the condition.
253 *
254 * The type inconsistency of the wait_event_*() __ret variable is also
255 * on purpose; we use long where we can return timeout values and int
256 * otherwise.
257 */
258
259 #define ___wait_event(wq_head, condition, state, exclusive, ret, cmd) \
260 ({ \
261 __label__ __out; \
262 struct wait_queue_entry __wq_entry; \
263 long __ret = ret; /* explicit shadow */ \
264 \
265 init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \
266 for (;;) { \
267 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
268 \
269 if (condition) \
270 break; \
271 \
272 if (___wait_is_interruptible(state) && __int) { \
273 __ret = __int; \
274 goto __out; \
275 } \
276 \
277 cmd; \
278 } \
279 finish_wait(&wq_head, &__wq_entry); \
280 __out: __ret; \
281 })
282
283 #define __wait_event(wq_head, condition) \
284 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
285 schedule())
286
287 /**
288 * wait_event - sleep until a condition gets true
289 * @wq_head: the waitqueue to wait on
290 * @condition: a C expression for the event to wait for
291 *
292 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
293 * @condition evaluates to true. The @condition is checked each time
294 * the waitqueue @wq_head is woken up.
295 *
296 * wake_up() has to be called after changing any variable that could
297 * change the result of the wait condition.
298 */
299 #define wait_event(wq_head, condition) \
300 do { \
301 might_sleep(); \
302 if (condition) \
303 break; \
304 __wait_event(wq_head, condition); \
305 } while (0)
306
307 #define __io_wait_event(wq_head, condition) \
308 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
309 io_schedule())
310
311 /*
312 * io_wait_event() -- like wait_event() but with io_schedule()
313 */
314 #define io_wait_event(wq_head, condition) \
315 do { \
316 might_sleep(); \
317 if (condition) \
318 break; \
319 __io_wait_event(wq_head, condition); \
320 } while (0)
321
322 #define __wait_event_freezable(wq_head, condition) \
323 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
324 freezable_schedule())
325
326 /**
327 * wait_event_freezable - sleep (or freeze) until a condition gets true
328 * @wq_head: the waitqueue to wait on
329 * @condition: a C expression for the event to wait for
330 *
331 * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
332 * to system load) until the @condition evaluates to true. The
333 * @condition is checked each time the waitqueue @wq_head is woken up.
334 *
335 * wake_up() has to be called after changing any variable that could
336 * change the result of the wait condition.
337 */
338 #define wait_event_freezable(wq_head, condition) \
339 ({ \
340 int __ret = 0; \
341 might_sleep(); \
342 if (!(condition)) \
343 __ret = __wait_event_freezable(wq_head, condition); \
344 __ret; \
345 })
346
347 #define __wait_event_timeout(wq_head, condition, timeout) \
348 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
349 TASK_UNINTERRUPTIBLE, 0, timeout, \
350 __ret = schedule_timeout(__ret))
351
352 /**
353 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
354 * @wq_head: the waitqueue to wait on
355 * @condition: a C expression for the event to wait for
356 * @timeout: timeout, in jiffies
357 *
358 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
359 * @condition evaluates to true. The @condition is checked each time
360 * the waitqueue @wq_head is woken up.
361 *
362 * wake_up() has to be called after changing any variable that could
363 * change the result of the wait condition.
364 *
365 * Returns:
366 * 0 if the @condition evaluated to %false after the @timeout elapsed,
367 * 1 if the @condition evaluated to %true after the @timeout elapsed,
368 * or the remaining jiffies (at least 1) if the @condition evaluated
369 * to %true before the @timeout elapsed.
370 */
371 #define wait_event_timeout(wq_head, condition, timeout) \
372 ({ \
373 long __ret = timeout; \
374 might_sleep(); \
375 if (!___wait_cond_timeout(condition)) \
376 __ret = __wait_event_timeout(wq_head, condition, timeout); \
377 __ret; \
378 })
379
380 #define __wait_event_freezable_timeout(wq_head, condition, timeout) \
381 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
382 TASK_INTERRUPTIBLE, 0, timeout, \
383 __ret = freezable_schedule_timeout(__ret))
384
385 /*
386 * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
387 * increasing load and is freezable.
388 */
389 #define wait_event_freezable_timeout(wq_head, condition, timeout) \
390 ({ \
391 long __ret = timeout; \
392 might_sleep(); \
393 if (!___wait_cond_timeout(condition)) \
394 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
395 __ret; \
396 })
397
398 #define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \
399 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0, \
400 cmd1; schedule(); cmd2)
401 /*
402 * Just like wait_event_cmd(), except it sets exclusive flag
403 */
404 #define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \
405 do { \
406 if (condition) \
407 break; \
408 __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2); \
409 } while (0)
410
411 #define __wait_event_cmd(wq_head, condition, cmd1, cmd2) \
412 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
413 cmd1; schedule(); cmd2)
414
415 /**
416 * wait_event_cmd - sleep until a condition gets true
417 * @wq_head: the waitqueue to wait on
418 * @condition: a C expression for the event to wait for
419 * @cmd1: the command will be executed before sleep
420 * @cmd2: the command will be executed after sleep
421 *
422 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
423 * @condition evaluates to true. The @condition is checked each time
424 * the waitqueue @wq_head is woken up.
425 *
426 * wake_up() has to be called after changing any variable that could
427 * change the result of the wait condition.
428 */
429 #define wait_event_cmd(wq_head, condition, cmd1, cmd2) \
430 do { \
431 if (condition) \
432 break; \
433 __wait_event_cmd(wq_head, condition, cmd1, cmd2); \
434 } while (0)
435
436 #define __wait_event_interruptible(wq_head, condition) \
437 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
438 schedule())
439
440 /**
441 * wait_event_interruptible - sleep until a condition gets true
442 * @wq_head: the waitqueue to wait on
443 * @condition: a C expression for the event to wait for
444 *
445 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
446 * @condition evaluates to true or a signal is received.
447 * The @condition is checked each time the waitqueue @wq_head is woken up.
448 *
449 * wake_up() has to be called after changing any variable that could
450 * change the result of the wait condition.
451 *
452 * The function will return -ERESTARTSYS if it was interrupted by a
453 * signal and 0 if @condition evaluated to true.
454 */
455 #define wait_event_interruptible(wq_head, condition) \
456 ({ \
457 int __ret = 0; \
458 might_sleep(); \
459 if (!(condition)) \
460 __ret = __wait_event_interruptible(wq_head, condition); \
461 __ret; \
462 })
463
464 #define __wait_event_interruptible_timeout(wq_head, condition, timeout) \
465 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
466 TASK_INTERRUPTIBLE, 0, timeout, \
467 __ret = schedule_timeout(__ret))
468
469 /**
470 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
471 * @wq_head: the waitqueue to wait on
472 * @condition: a C expression for the event to wait for
473 * @timeout: timeout, in jiffies
474 *
475 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
476 * @condition evaluates to true or a signal is received.
477 * The @condition is checked each time the waitqueue @wq_head is woken up.
478 *
479 * wake_up() has to be called after changing any variable that could
480 * change the result of the wait condition.
481 *
482 * Returns:
483 * 0 if the @condition evaluated to %false after the @timeout elapsed,
484 * 1 if the @condition evaluated to %true after the @timeout elapsed,
485 * the remaining jiffies (at least 1) if the @condition evaluated
486 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
487 * interrupted by a signal.
488 */
489 #define wait_event_interruptible_timeout(wq_head, condition, timeout) \
490 ({ \
491 long __ret = timeout; \
492 might_sleep(); \
493 if (!___wait_cond_timeout(condition)) \
494 __ret = __wait_event_interruptible_timeout(wq_head, \
495 condition, timeout); \
496 __ret; \
497 })
498
499 #define __wait_event_hrtimeout(wq_head, condition, timeout, state) \
500 ({ \
501 int __ret = 0; \
502 struct hrtimer_sleeper __t; \
503 \
504 hrtimer_init_sleeper_on_stack(&__t, CLOCK_MONOTONIC, \
505 HRTIMER_MODE_REL); \
506 if ((timeout) != KTIME_MAX) \
507 hrtimer_start_range_ns(&__t.timer, timeout, \
508 current->timer_slack_ns, \
509 HRTIMER_MODE_REL); \
510 \
511 __ret = ___wait_event(wq_head, condition, state, 0, 0, \
512 if (!__t.task) { \
513 __ret = -ETIME; \
514 break; \
515 } \
516 schedule()); \
517 \
518 hrtimer_cancel(&__t.timer); \
519 destroy_hrtimer_on_stack(&__t.timer); \
520 __ret; \
521 })
522
523 /**
524 * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
525 * @wq_head: the waitqueue to wait on
526 * @condition: a C expression for the event to wait for
527 * @timeout: timeout, as a ktime_t
528 *
529 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
530 * @condition evaluates to true or a signal is received.
531 * The @condition is checked each time the waitqueue @wq_head is woken up.
532 *
533 * wake_up() has to be called after changing any variable that could
534 * change the result of the wait condition.
535 *
536 * The function returns 0 if @condition became true, or -ETIME if the timeout
537 * elapsed.
538 */
539 #define wait_event_hrtimeout(wq_head, condition, timeout) \
540 ({ \
541 int __ret = 0; \
542 might_sleep(); \
543 if (!(condition)) \
544 __ret = __wait_event_hrtimeout(wq_head, condition, timeout, \
545 TASK_UNINTERRUPTIBLE); \
546 __ret; \
547 })
548
549 /**
550 * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
551 * @wq: the waitqueue to wait on
552 * @condition: a C expression for the event to wait for
553 * @timeout: timeout, as a ktime_t
554 *
555 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
556 * @condition evaluates to true or a signal is received.
557 * The @condition is checked each time the waitqueue @wq is woken up.
558 *
559 * wake_up() has to be called after changing any variable that could
560 * change the result of the wait condition.
561 *
562 * The function returns 0 if @condition became true, -ERESTARTSYS if it was
563 * interrupted by a signal, or -ETIME if the timeout elapsed.
564 */
565 #define wait_event_interruptible_hrtimeout(wq, condition, timeout) \
566 ({ \
567 long __ret = 0; \
568 might_sleep(); \
569 if (!(condition)) \
570 __ret = __wait_event_hrtimeout(wq, condition, timeout, \
571 TASK_INTERRUPTIBLE); \
572 __ret; \
573 })
574
575 #define __wait_event_interruptible_exclusive(wq, condition) \
576 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
577 schedule())
578
579 #define wait_event_interruptible_exclusive(wq, condition) \
580 ({ \
581 int __ret = 0; \
582 might_sleep(); \
583 if (!(condition)) \
584 __ret = __wait_event_interruptible_exclusive(wq, condition); \
585 __ret; \
586 })
587
588 #define __wait_event_killable_exclusive(wq, condition) \
589 ___wait_event(wq, condition, TASK_KILLABLE, 1, 0, \
590 schedule())
591
592 #define wait_event_killable_exclusive(wq, condition) \
593 ({ \
594 int __ret = 0; \
595 might_sleep(); \
596 if (!(condition)) \
597 __ret = __wait_event_killable_exclusive(wq, condition); \
598 __ret; \
599 })
600
601
602 #define __wait_event_freezable_exclusive(wq, condition) \
603 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
604 freezable_schedule())
605
606 #define wait_event_freezable_exclusive(wq, condition) \
607 ({ \
608 int __ret = 0; \
609 might_sleep(); \
610 if (!(condition)) \
611 __ret = __wait_event_freezable_exclusive(wq, condition); \
612 __ret; \
613 })
614
615 /**
616 * wait_event_idle - wait for a condition without contributing to system load
617 * @wq_head: the waitqueue to wait on
618 * @condition: a C expression for the event to wait for
619 *
620 * The process is put to sleep (TASK_IDLE) until the
621 * @condition evaluates to true.
622 * The @condition is checked each time the waitqueue @wq_head is woken up.
623 *
624 * wake_up() has to be called after changing any variable that could
625 * change the result of the wait condition.
626 *
627 */
628 #define wait_event_idle(wq_head, condition) \
629 do { \
630 might_sleep(); \
631 if (!(condition)) \
632 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \
633 } while (0)
634
635 /**
636 * wait_event_idle_exclusive - wait for a condition with contributing to system load
637 * @wq_head: the waitqueue to wait on
638 * @condition: a C expression for the event to wait for
639 *
640 * The process is put to sleep (TASK_IDLE) until the
641 * @condition evaluates to true.
642 * The @condition is checked each time the waitqueue @wq_head is woken up.
643 *
644 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
645 * set thus if other processes wait on the same list, when this
646 * process is woken further processes are not considered.
647 *
648 * wake_up() has to be called after changing any variable that could
649 * change the result of the wait condition.
650 *
651 */
652 #define wait_event_idle_exclusive(wq_head, condition) \
653 do { \
654 might_sleep(); \
655 if (!(condition)) \
656 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \
657 } while (0)
658
659 #define __wait_event_idle_timeout(wq_head, condition, timeout) \
660 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
661 TASK_IDLE, 0, timeout, \
662 __ret = schedule_timeout(__ret))
663
664 /**
665 * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses
666 * @wq_head: the waitqueue to wait on
667 * @condition: a C expression for the event to wait for
668 * @timeout: timeout, in jiffies
669 *
670 * The process is put to sleep (TASK_IDLE) until the
671 * @condition evaluates to true. The @condition is checked each time
672 * the waitqueue @wq_head is woken up.
673 *
674 * wake_up() has to be called after changing any variable that could
675 * change the result of the wait condition.
676 *
677 * Returns:
678 * 0 if the @condition evaluated to %false after the @timeout elapsed,
679 * 1 if the @condition evaluated to %true after the @timeout elapsed,
680 * or the remaining jiffies (at least 1) if the @condition evaluated
681 * to %true before the @timeout elapsed.
682 */
683 #define wait_event_idle_timeout(wq_head, condition, timeout) \
684 ({ \
685 long __ret = timeout; \
686 might_sleep(); \
687 if (!___wait_cond_timeout(condition)) \
688 __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \
689 __ret; \
690 })
691
692 #define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout) \
693 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
694 TASK_IDLE, 1, timeout, \
695 __ret = schedule_timeout(__ret))
696
697 /**
698 * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses
699 * @wq_head: the waitqueue to wait on
700 * @condition: a C expression for the event to wait for
701 * @timeout: timeout, in jiffies
702 *
703 * The process is put to sleep (TASK_IDLE) until the
704 * @condition evaluates to true. The @condition is checked each time
705 * the waitqueue @wq_head is woken up.
706 *
707 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
708 * set thus if other processes wait on the same list, when this
709 * process is woken further processes are not considered.
710 *
711 * wake_up() has to be called after changing any variable that could
712 * change the result of the wait condition.
713 *
714 * Returns:
715 * 0 if the @condition evaluated to %false after the @timeout elapsed,
716 * 1 if the @condition evaluated to %true after the @timeout elapsed,
717 * or the remaining jiffies (at least 1) if the @condition evaluated
718 * to %true before the @timeout elapsed.
719 */
720 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout) \
721 ({ \
722 long __ret = timeout; \
723 might_sleep(); \
724 if (!___wait_cond_timeout(condition)) \
725 __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\
726 __ret; \
727 })
728
729 extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
730 extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
731
732 #define __wait_event_interruptible_locked(wq, condition, exclusive, fn) \
733 ({ \
734 int __ret; \
735 DEFINE_WAIT(__wait); \
736 if (exclusive) \
737 __wait.flags |= WQ_FLAG_EXCLUSIVE; \
738 do { \
739 __ret = fn(&(wq), &__wait); \
740 if (__ret) \
741 break; \
742 } while (!(condition)); \
743 __remove_wait_queue(&(wq), &__wait); \
744 __set_current_state(TASK_RUNNING); \
745 __ret; \
746 })
747
748
749 /**
750 * wait_event_interruptible_locked - sleep until a condition gets true
751 * @wq: the waitqueue to wait on
752 * @condition: a C expression for the event to wait for
753 *
754 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
755 * @condition evaluates to true or a signal is received.
756 * The @condition is checked each time the waitqueue @wq is woken up.
757 *
758 * It must be called with wq.lock being held. This spinlock is
759 * unlocked while sleeping but @condition testing is done while lock
760 * is held and when this macro exits the lock is held.
761 *
762 * The lock is locked/unlocked using spin_lock()/spin_unlock()
763 * functions which must match the way they are locked/unlocked outside
764 * of this macro.
765 *
766 * wake_up_locked() has to be called after changing any variable that could
767 * change the result of the wait condition.
768 *
769 * The function will return -ERESTARTSYS if it was interrupted by a
770 * signal and 0 if @condition evaluated to true.
771 */
772 #define wait_event_interruptible_locked(wq, condition) \
773 ((condition) \
774 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
775
776 /**
777 * wait_event_interruptible_locked_irq - sleep until a condition gets true
778 * @wq: the waitqueue to wait on
779 * @condition: a C expression for the event to wait for
780 *
781 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
782 * @condition evaluates to true or a signal is received.
783 * The @condition is checked each time the waitqueue @wq is woken up.
784 *
785 * It must be called with wq.lock being held. This spinlock is
786 * unlocked while sleeping but @condition testing is done while lock
787 * is held and when this macro exits the lock is held.
788 *
789 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
790 * functions which must match the way they are locked/unlocked outside
791 * of this macro.
792 *
793 * wake_up_locked() has to be called after changing any variable that could
794 * change the result of the wait condition.
795 *
796 * The function will return -ERESTARTSYS if it was interrupted by a
797 * signal and 0 if @condition evaluated to true.
798 */
799 #define wait_event_interruptible_locked_irq(wq, condition) \
800 ((condition) \
801 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
802
803 /**
804 * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
805 * @wq: the waitqueue to wait on
806 * @condition: a C expression for the event to wait for
807 *
808 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
809 * @condition evaluates to true or a signal is received.
810 * The @condition is checked each time the waitqueue @wq is woken up.
811 *
812 * It must be called with wq.lock being held. This spinlock is
813 * unlocked while sleeping but @condition testing is done while lock
814 * is held and when this macro exits the lock is held.
815 *
816 * The lock is locked/unlocked using spin_lock()/spin_unlock()
817 * functions which must match the way they are locked/unlocked outside
818 * of this macro.
819 *
820 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
821 * set thus when other process waits process on the list if this
822 * process is awaken further processes are not considered.
823 *
824 * wake_up_locked() has to be called after changing any variable that could
825 * change the result of the wait condition.
826 *
827 * The function will return -ERESTARTSYS if it was interrupted by a
828 * signal and 0 if @condition evaluated to true.
829 */
830 #define wait_event_interruptible_exclusive_locked(wq, condition) \
831 ((condition) \
832 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
833
834 /**
835 * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
836 * @wq: the waitqueue to wait on
837 * @condition: a C expression for the event to wait for
838 *
839 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
840 * @condition evaluates to true or a signal is received.
841 * The @condition is checked each time the waitqueue @wq is woken up.
842 *
843 * It must be called with wq.lock being held. This spinlock is
844 * unlocked while sleeping but @condition testing is done while lock
845 * is held and when this macro exits the lock is held.
846 *
847 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
848 * functions which must match the way they are locked/unlocked outside
849 * of this macro.
850 *
851 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
852 * set thus when other process waits process on the list if this
853 * process is awaken further processes are not considered.
854 *
855 * wake_up_locked() has to be called after changing any variable that could
856 * change the result of the wait condition.
857 *
858 * The function will return -ERESTARTSYS if it was interrupted by a
859 * signal and 0 if @condition evaluated to true.
860 */
861 #define wait_event_interruptible_exclusive_locked_irq(wq, condition) \
862 ((condition) \
863 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
864
865
866 #define __wait_event_killable(wq, condition) \
867 ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
868
869 /**
870 * wait_event_killable - sleep until a condition gets true
871 * @wq_head: the waitqueue to wait on
872 * @condition: a C expression for the event to wait for
873 *
874 * The process is put to sleep (TASK_KILLABLE) until the
875 * @condition evaluates to true or a signal is received.
876 * The @condition is checked each time the waitqueue @wq_head is woken up.
877 *
878 * wake_up() has to be called after changing any variable that could
879 * change the result of the wait condition.
880 *
881 * The function will return -ERESTARTSYS if it was interrupted by a
882 * signal and 0 if @condition evaluated to true.
883 */
884 #define wait_event_killable(wq_head, condition) \
885 ({ \
886 int __ret = 0; \
887 might_sleep(); \
888 if (!(condition)) \
889 __ret = __wait_event_killable(wq_head, condition); \
890 __ret; \
891 })
892
893 #define __wait_event_killable_timeout(wq_head, condition, timeout) \
894 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
895 TASK_KILLABLE, 0, timeout, \
896 __ret = schedule_timeout(__ret))
897
898 /**
899 * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
900 * @wq_head: the waitqueue to wait on
901 * @condition: a C expression for the event to wait for
902 * @timeout: timeout, in jiffies
903 *
904 * The process is put to sleep (TASK_KILLABLE) until the
905 * @condition evaluates to true or a kill signal is received.
906 * The @condition is checked each time the waitqueue @wq_head is woken up.
907 *
908 * wake_up() has to be called after changing any variable that could
909 * change the result of the wait condition.
910 *
911 * Returns:
912 * 0 if the @condition evaluated to %false after the @timeout elapsed,
913 * 1 if the @condition evaluated to %true after the @timeout elapsed,
914 * the remaining jiffies (at least 1) if the @condition evaluated
915 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
916 * interrupted by a kill signal.
917 *
918 * Only kill signals interrupt this process.
919 */
920 #define wait_event_killable_timeout(wq_head, condition, timeout) \
921 ({ \
922 long __ret = timeout; \
923 might_sleep(); \
924 if (!___wait_cond_timeout(condition)) \
925 __ret = __wait_event_killable_timeout(wq_head, \
926 condition, timeout); \
927 __ret; \
928 })
929
930
931 #define __wait_event_lock_irq(wq_head, condition, lock, cmd) \
932 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
933 spin_unlock_irq(&lock); \
934 cmd; \
935 schedule(); \
936 spin_lock_irq(&lock))
937
938 /**
939 * wait_event_lock_irq_cmd - sleep until a condition gets true. The
940 * condition is checked under the lock. This
941 * is expected to be called with the lock
942 * taken.
943 * @wq_head: the waitqueue to wait on
944 * @condition: a C expression for the event to wait for
945 * @lock: a locked spinlock_t, which will be released before cmd
946 * and schedule() and reacquired afterwards.
947 * @cmd: a command which is invoked outside the critical section before
948 * sleep
949 *
950 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
951 * @condition evaluates to true. The @condition is checked each time
952 * the waitqueue @wq_head is woken up.
953 *
954 * wake_up() has to be called after changing any variable that could
955 * change the result of the wait condition.
956 *
957 * This is supposed to be called while holding the lock. The lock is
958 * dropped before invoking the cmd and going to sleep and is reacquired
959 * afterwards.
960 */
961 #define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd) \
962 do { \
963 if (condition) \
964 break; \
965 __wait_event_lock_irq(wq_head, condition, lock, cmd); \
966 } while (0)
967
968 /**
969 * wait_event_lock_irq - sleep until a condition gets true. The
970 * condition is checked under the lock. This
971 * is expected to be called with the lock
972 * taken.
973 * @wq_head: the waitqueue to wait on
974 * @condition: a C expression for the event to wait for
975 * @lock: a locked spinlock_t, which will be released before schedule()
976 * and reacquired afterwards.
977 *
978 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
979 * @condition evaluates to true. The @condition is checked each time
980 * the waitqueue @wq_head is woken up.
981 *
982 * wake_up() has to be called after changing any variable that could
983 * change the result of the wait condition.
984 *
985 * This is supposed to be called while holding the lock. The lock is
986 * dropped before going to sleep and is reacquired afterwards.
987 */
988 #define wait_event_lock_irq(wq_head, condition, lock) \
989 do { \
990 if (condition) \
991 break; \
992 __wait_event_lock_irq(wq_head, condition, lock, ); \
993 } while (0)
994
995
996 #define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd) \
997 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
998 spin_unlock_irq(&lock); \
999 cmd; \
1000 schedule(); \
1001 spin_lock_irq(&lock))
1002
1003 /**
1004 * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
1005 * The condition is checked under the lock. This is expected to
1006 * be called with the lock taken.
1007 * @wq_head: the waitqueue to wait on
1008 * @condition: a C expression for the event to wait for
1009 * @lock: a locked spinlock_t, which will be released before cmd and
1010 * schedule() and reacquired afterwards.
1011 * @cmd: a command which is invoked outside the critical section before
1012 * sleep
1013 *
1014 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1015 * @condition evaluates to true or a signal is received. The @condition is
1016 * checked each time the waitqueue @wq_head is woken up.
1017 *
1018 * wake_up() has to be called after changing any variable that could
1019 * change the result of the wait condition.
1020 *
1021 * This is supposed to be called while holding the lock. The lock is
1022 * dropped before invoking the cmd and going to sleep and is reacquired
1023 * afterwards.
1024 *
1025 * The macro will return -ERESTARTSYS if it was interrupted by a signal
1026 * and 0 if @condition evaluated to true.
1027 */
1028 #define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd) \
1029 ({ \
1030 int __ret = 0; \
1031 if (!(condition)) \
1032 __ret = __wait_event_interruptible_lock_irq(wq_head, \
1033 condition, lock, cmd); \
1034 __ret; \
1035 })
1036
1037 /**
1038 * wait_event_interruptible_lock_irq - sleep until a condition gets true.
1039 * The condition is checked under the lock. This is expected
1040 * to be called with the lock taken.
1041 * @wq_head: the waitqueue to wait on
1042 * @condition: a C expression for the event to wait for
1043 * @lock: a locked spinlock_t, which will be released before schedule()
1044 * and reacquired afterwards.
1045 *
1046 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1047 * @condition evaluates to true or signal is received. The @condition is
1048 * checked each time the waitqueue @wq_head is woken up.
1049 *
1050 * wake_up() has to be called after changing any variable that could
1051 * change the result of the wait condition.
1052 *
1053 * This is supposed to be called while holding the lock. The lock is
1054 * dropped before going to sleep and is reacquired afterwards.
1055 *
1056 * The macro will return -ERESTARTSYS if it was interrupted by a signal
1057 * and 0 if @condition evaluated to true.
1058 */
1059 #define wait_event_interruptible_lock_irq(wq_head, condition, lock) \
1060 ({ \
1061 int __ret = 0; \
1062 if (!(condition)) \
1063 __ret = __wait_event_interruptible_lock_irq(wq_head, \
1064 condition, lock,); \
1065 __ret; \
1066 })
1067
1068 #define __wait_event_lock_irq_timeout(wq_head, condition, lock, timeout, state) \
1069 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
1070 state, 0, timeout, \
1071 spin_unlock_irq(&lock); \
1072 __ret = schedule_timeout(__ret); \
1073 spin_lock_irq(&lock));
1074
1075 /**
1076 * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
1077 * true or a timeout elapses. The condition is checked under
1078 * the lock. This is expected to be called with the lock taken.
1079 * @wq_head: the waitqueue to wait on
1080 * @condition: a C expression for the event to wait for
1081 * @lock: a locked spinlock_t, which will be released before schedule()
1082 * and reacquired afterwards.
1083 * @timeout: timeout, in jiffies
1084 *
1085 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1086 * @condition evaluates to true or signal is received. The @condition is
1087 * checked each time the waitqueue @wq_head is woken up.
1088 *
1089 * wake_up() has to be called after changing any variable that could
1090 * change the result of the wait condition.
1091 *
1092 * This is supposed to be called while holding the lock. The lock is
1093 * dropped before going to sleep and is reacquired afterwards.
1094 *
1095 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
1096 * was interrupted by a signal, and the remaining jiffies otherwise
1097 * if the condition evaluated to true before the timeout elapsed.
1098 */
1099 #define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock, \
1100 timeout) \
1101 ({ \
1102 long __ret = timeout; \
1103 if (!___wait_cond_timeout(condition)) \
1104 __ret = __wait_event_lock_irq_timeout( \
1105 wq_head, condition, lock, timeout, \
1106 TASK_INTERRUPTIBLE); \
1107 __ret; \
1108 })
1109
1110 #define wait_event_lock_irq_timeout(wq_head, condition, lock, timeout) \
1111 ({ \
1112 long __ret = timeout; \
1113 if (!___wait_cond_timeout(condition)) \
1114 __ret = __wait_event_lock_irq_timeout( \
1115 wq_head, condition, lock, timeout, \
1116 TASK_UNINTERRUPTIBLE); \
1117 __ret; \
1118 })
1119
1120 /*
1121 * Waitqueues which are removed from the waitqueue_head at wakeup time
1122 */
1123 void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1124 void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1125 long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1126 void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
1127 long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
1128 int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1129 int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1130
1131 #define DEFINE_WAIT_FUNC(name, function) \
1132 struct wait_queue_entry name = { \
1133 .private = current, \
1134 .func = function, \
1135 .entry = LIST_HEAD_INIT((name).entry), \
1136 }
1137
1138 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
1139
1140 #define init_wait(wait) \
1141 do { \
1142 (wait)->private = current; \
1143 (wait)->func = autoremove_wake_function; \
1144 INIT_LIST_HEAD(&(wait)->entry); \
1145 (wait)->flags = 0; \
1146 } while (0)
1147
1148 #endif /* _LINUX_WAIT_H */