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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
14typedef struct wait_queue_entry wait_queue_entry_t;
15
16typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
17int 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#define WQ_FLAG_CUSTOM 0x08
24#define WQ_FLAG_DONE 0x10
25
26/*
27 * A single wait-queue entry structure:
28 */
29struct wait_queue_entry {
30 unsigned int flags;
31 void *private;
32 wait_queue_func_t func;
33 struct list_head entry;
34};
35
36struct wait_queue_head {
37 spinlock_t lock;
38 struct list_head head;
39};
40typedef struct wait_queue_head wait_queue_head_t;
41
42struct task_struct;
43
44/*
45 * Macros for declaration and initialisaton of the datatypes
46 */
47
48#define __WAITQUEUE_INITIALIZER(name, tsk) { \
49 .private = tsk, \
50 .func = default_wake_function, \
51 .entry = { NULL, NULL } }
52
53#define DECLARE_WAITQUEUE(name, tsk) \
54 struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk)
55
56#define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
57 .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
58 .head = { &(name).head, &(name).head } }
59
60#define DECLARE_WAIT_QUEUE_HEAD(name) \
61 struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
62
63extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
64
65#define init_waitqueue_head(wq_head) \
66 do { \
67 static struct lock_class_key __key; \
68 \
69 __init_waitqueue_head((wq_head), #wq_head, &__key); \
70 } while (0)
71
72#ifdef CONFIG_LOCKDEP
73# define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
74 ({ init_waitqueue_head(&name); name; })
75# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
76 struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
77#else
78# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
79#endif
80
81static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p)
82{
83 wq_entry->flags = 0;
84 wq_entry->private = p;
85 wq_entry->func = default_wake_function;
86}
87
88static inline void
89init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func)
90{
91 wq_entry->flags = 0;
92 wq_entry->private = NULL;
93 wq_entry->func = func;
94}
95
96/**
97 * waitqueue_active -- locklessly test for waiters on the queue
98 * @wq_head: the waitqueue to test for waiters
99 *
100 * returns true if the wait list is not empty
101 *
102 * NOTE: this function is lockless and requires care, incorrect usage _will_
103 * lead to sporadic and non-obvious failure.
104 *
105 * Use either while holding wait_queue_head::lock or when used for wakeups
106 * with an extra smp_mb() like::
107 *
108 * CPU0 - waker CPU1 - waiter
109 *
110 * for (;;) {
111 * @cond = true; prepare_to_wait(&wq_head, &wait, state);
112 * smp_mb(); // smp_mb() from set_current_state()
113 * if (waitqueue_active(wq_head)) if (@cond)
114 * wake_up(wq_head); break;
115 * schedule();
116 * }
117 * finish_wait(&wq_head, &wait);
118 *
119 * Because without the explicit smp_mb() it's possible for the
120 * waitqueue_active() load to get hoisted over the @cond store such that we'll
121 * observe an empty wait list while the waiter might not observe @cond.
122 *
123 * Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
124 * which (when the lock is uncontended) are of roughly equal cost.
125 */
126static inline int waitqueue_active(struct wait_queue_head *wq_head)
127{
128 return !list_empty(&wq_head->head);
129}
130
131/**
132 * wq_has_single_sleeper - check if there is only one sleeper
133 * @wq_head: wait queue head
134 *
135 * Returns true of wq_head has only one sleeper on the list.
136 *
137 * Please refer to the comment for waitqueue_active.
138 */
139static inline bool wq_has_single_sleeper(struct wait_queue_head *wq_head)
140{
141 return list_is_singular(&wq_head->head);
142}
143
144/**
145 * wq_has_sleeper - check if there are any waiting processes
146 * @wq_head: wait queue head
147 *
148 * Returns true if wq_head has waiting processes
149 *
150 * Please refer to the comment for waitqueue_active.
151 */
152static inline bool wq_has_sleeper(struct wait_queue_head *wq_head)
153{
154 /*
155 * We need to be sure we are in sync with the
156 * add_wait_queue modifications to the wait queue.
157 *
158 * This memory barrier should be paired with one on the
159 * waiting side.
160 */
161 smp_mb();
162 return waitqueue_active(wq_head);
163}
164
165extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
166extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
167extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
168
169static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
170{
171 list_add(&wq_entry->entry, &wq_head->head);
172}
173
174/*
175 * Used for wake-one threads:
176 */
177static inline void
178__add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
179{
180 wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
181 __add_wait_queue(wq_head, wq_entry);
182}
183
184static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
185{
186 list_add_tail(&wq_entry->entry, &wq_head->head);
187}
188
189static inline void
190__add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
191{
192 wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
193 __add_wait_queue_entry_tail(wq_head, wq_entry);
194}
195
196static inline void
197__remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
198{
199 list_del(&wq_entry->entry);
200}
201
202void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
203void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
204void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
205 unsigned int mode, void *key, wait_queue_entry_t *bookmark);
206void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
207void __wake_up_locked_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
208void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
209void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode);
210
211#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
212#define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
213#define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
214#define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1)
215#define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0)
216
217#define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
218#define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
219#define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
220#define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE)
221
222/*
223 * Wakeup macros to be used to report events to the targets.
224 */
225#define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m))
226#define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m))
227#define wake_up_poll(x, m) \
228 __wake_up(x, TASK_NORMAL, 1, poll_to_key(m))
229#define wake_up_locked_poll(x, m) \
230 __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m))
231#define wake_up_interruptible_poll(x, m) \
232 __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m))
233#define wake_up_interruptible_sync_poll(x, m) \
234 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m))
235#define wake_up_interruptible_sync_poll_locked(x, m) \
236 __wake_up_locked_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m))
237
238#define ___wait_cond_timeout(condition) \
239({ \
240 bool __cond = (condition); \
241 if (__cond && !__ret) \
242 __ret = 1; \
243 __cond || !__ret; \
244})
245
246#define ___wait_is_interruptible(state) \
247 (!__builtin_constant_p(state) || \
248 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \
249
250extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
251
252/*
253 * The below macro ___wait_event() has an explicit shadow of the __ret
254 * variable when used from the wait_event_*() macros.
255 *
256 * This is so that both can use the ___wait_cond_timeout() construct
257 * to wrap the condition.
258 *
259 * The type inconsistency of the wait_event_*() __ret variable is also
260 * on purpose; we use long where we can return timeout values and int
261 * otherwise.
262 */
263
264#define ___wait_event(wq_head, condition, state, exclusive, ret, cmd) \
265({ \
266 __label__ __out; \
267 struct wait_queue_entry __wq_entry; \
268 long __ret = ret; /* explicit shadow */ \
269 \
270 init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \
271 for (;;) { \
272 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
273 \
274 if (condition) \
275 break; \
276 \
277 if (___wait_is_interruptible(state) && __int) { \
278 __ret = __int; \
279 goto __out; \
280 } \
281 \
282 cmd; \
283 } \
284 finish_wait(&wq_head, &__wq_entry); \
285__out: __ret; \
286})
287
288#define __wait_event(wq_head, condition) \
289 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
290 schedule())
291
292/**
293 * wait_event - sleep until a condition gets true
294 * @wq_head: the waitqueue to wait on
295 * @condition: a C expression for the event to wait for
296 *
297 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
298 * @condition evaluates to true. The @condition is checked each time
299 * the waitqueue @wq_head is woken up.
300 *
301 * wake_up() has to be called after changing any variable that could
302 * change the result of the wait condition.
303 */
304#define wait_event(wq_head, condition) \
305do { \
306 might_sleep(); \
307 if (condition) \
308 break; \
309 __wait_event(wq_head, condition); \
310} while (0)
311
312#define __io_wait_event(wq_head, condition) \
313 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
314 io_schedule())
315
316/*
317 * io_wait_event() -- like wait_event() but with io_schedule()
318 */
319#define io_wait_event(wq_head, condition) \
320do { \
321 might_sleep(); \
322 if (condition) \
323 break; \
324 __io_wait_event(wq_head, condition); \
325} while (0)
326
327#define __wait_event_freezable(wq_head, condition) \
328 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
329 freezable_schedule())
330
331/**
332 * wait_event_freezable - sleep (or freeze) until a condition gets true
333 * @wq_head: the waitqueue to wait on
334 * @condition: a C expression for the event to wait for
335 *
336 * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
337 * to system load) until the @condition evaluates to true. The
338 * @condition is checked each time the waitqueue @wq_head is woken up.
339 *
340 * wake_up() has to be called after changing any variable that could
341 * change the result of the wait condition.
342 */
343#define wait_event_freezable(wq_head, condition) \
344({ \
345 int __ret = 0; \
346 might_sleep(); \
347 if (!(condition)) \
348 __ret = __wait_event_freezable(wq_head, condition); \
349 __ret; \
350})
351
352#define __wait_event_timeout(wq_head, condition, timeout) \
353 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
354 TASK_UNINTERRUPTIBLE, 0, timeout, \
355 __ret = schedule_timeout(__ret))
356
357/**
358 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
359 * @wq_head: the waitqueue to wait on
360 * @condition: a C expression for the event to wait for
361 * @timeout: timeout, in jiffies
362 *
363 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
364 * @condition evaluates to true. The @condition is checked each time
365 * the waitqueue @wq_head is woken up.
366 *
367 * wake_up() has to be called after changing any variable that could
368 * change the result of the wait condition.
369 *
370 * Returns:
371 * 0 if the @condition evaluated to %false after the @timeout elapsed,
372 * 1 if the @condition evaluated to %true after the @timeout elapsed,
373 * or the remaining jiffies (at least 1) if the @condition evaluated
374 * to %true before the @timeout elapsed.
375 */
376#define wait_event_timeout(wq_head, condition, timeout) \
377({ \
378 long __ret = timeout; \
379 might_sleep(); \
380 if (!___wait_cond_timeout(condition)) \
381 __ret = __wait_event_timeout(wq_head, condition, timeout); \
382 __ret; \
383})
384
385#define __wait_event_freezable_timeout(wq_head, condition, timeout) \
386 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
387 TASK_INTERRUPTIBLE, 0, timeout, \
388 __ret = freezable_schedule_timeout(__ret))
389
390/*
391 * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
392 * increasing load and is freezable.
393 */
394#define wait_event_freezable_timeout(wq_head, condition, timeout) \
395({ \
396 long __ret = timeout; \
397 might_sleep(); \
398 if (!___wait_cond_timeout(condition)) \
399 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
400 __ret; \
401})
402
403#define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \
404 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0, \
405 cmd1; schedule(); cmd2)
406/*
407 * Just like wait_event_cmd(), except it sets exclusive flag
408 */
409#define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \
410do { \
411 if (condition) \
412 break; \
413 __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2); \
414} while (0)
415
416#define __wait_event_cmd(wq_head, condition, cmd1, cmd2) \
417 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
418 cmd1; schedule(); cmd2)
419
420/**
421 * wait_event_cmd - sleep until a condition gets true
422 * @wq_head: the waitqueue to wait on
423 * @condition: a C expression for the event to wait for
424 * @cmd1: the command will be executed before sleep
425 * @cmd2: the command will be executed after sleep
426 *
427 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
428 * @condition evaluates to true. The @condition is checked each time
429 * the waitqueue @wq_head is woken up.
430 *
431 * wake_up() has to be called after changing any variable that could
432 * change the result of the wait condition.
433 */
434#define wait_event_cmd(wq_head, condition, cmd1, cmd2) \
435do { \
436 if (condition) \
437 break; \
438 __wait_event_cmd(wq_head, condition, cmd1, cmd2); \
439} while (0)
440
441#define __wait_event_interruptible(wq_head, condition) \
442 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
443 schedule())
444
445/**
446 * wait_event_interruptible - sleep until a condition gets true
447 * @wq_head: the waitqueue to wait on
448 * @condition: a C expression for the event to wait for
449 *
450 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
451 * @condition evaluates to true or a signal is received.
452 * The @condition is checked each time the waitqueue @wq_head is woken up.
453 *
454 * wake_up() has to be called after changing any variable that could
455 * change the result of the wait condition.
456 *
457 * The function will return -ERESTARTSYS if it was interrupted by a
458 * signal and 0 if @condition evaluated to true.
459 */
460#define wait_event_interruptible(wq_head, condition) \
461({ \
462 int __ret = 0; \
463 might_sleep(); \
464 if (!(condition)) \
465 __ret = __wait_event_interruptible(wq_head, condition); \
466 __ret; \
467})
468
469#define __wait_event_interruptible_timeout(wq_head, condition, timeout) \
470 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
471 TASK_INTERRUPTIBLE, 0, timeout, \
472 __ret = schedule_timeout(__ret))
473
474/**
475 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
476 * @wq_head: the waitqueue to wait on
477 * @condition: a C expression for the event to wait for
478 * @timeout: timeout, in jiffies
479 *
480 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
481 * @condition evaluates to true or a signal is received.
482 * The @condition is checked each time the waitqueue @wq_head is woken up.
483 *
484 * wake_up() has to be called after changing any variable that could
485 * change the result of the wait condition.
486 *
487 * Returns:
488 * 0 if the @condition evaluated to %false after the @timeout elapsed,
489 * 1 if the @condition evaluated to %true after the @timeout elapsed,
490 * the remaining jiffies (at least 1) if the @condition evaluated
491 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
492 * interrupted by a signal.
493 */
494#define wait_event_interruptible_timeout(wq_head, condition, timeout) \
495({ \
496 long __ret = timeout; \
497 might_sleep(); \
498 if (!___wait_cond_timeout(condition)) \
499 __ret = __wait_event_interruptible_timeout(wq_head, \
500 condition, timeout); \
501 __ret; \
502})
503
504#define __wait_event_hrtimeout(wq_head, condition, timeout, state) \
505({ \
506 int __ret = 0; \
507 struct hrtimer_sleeper __t; \
508 \
509 hrtimer_init_sleeper_on_stack(&__t, CLOCK_MONOTONIC, \
510 HRTIMER_MODE_REL); \
511 if ((timeout) != KTIME_MAX) \
512 hrtimer_start_range_ns(&__t.timer, timeout, \
513 current->timer_slack_ns, \
514 HRTIMER_MODE_REL); \
515 \
516 __ret = ___wait_event(wq_head, condition, state, 0, 0, \
517 if (!__t.task) { \
518 __ret = -ETIME; \
519 break; \
520 } \
521 schedule()); \
522 \
523 hrtimer_cancel(&__t.timer); \
524 destroy_hrtimer_on_stack(&__t.timer); \
525 __ret; \
526})
527
528/**
529 * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
530 * @wq_head: the waitqueue to wait on
531 * @condition: a C expression for the event to wait for
532 * @timeout: timeout, as a ktime_t
533 *
534 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
535 * @condition evaluates to true or a signal is received.
536 * The @condition is checked each time the waitqueue @wq_head is woken up.
537 *
538 * wake_up() has to be called after changing any variable that could
539 * change the result of the wait condition.
540 *
541 * The function returns 0 if @condition became true, or -ETIME if the timeout
542 * elapsed.
543 */
544#define wait_event_hrtimeout(wq_head, condition, timeout) \
545({ \
546 int __ret = 0; \
547 might_sleep(); \
548 if (!(condition)) \
549 __ret = __wait_event_hrtimeout(wq_head, condition, timeout, \
550 TASK_UNINTERRUPTIBLE); \
551 __ret; \
552})
553
554/**
555 * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
556 * @wq: the waitqueue to wait on
557 * @condition: a C expression for the event to wait for
558 * @timeout: timeout, as a ktime_t
559 *
560 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
561 * @condition evaluates to true or a signal is received.
562 * The @condition is checked each time the waitqueue @wq is woken up.
563 *
564 * wake_up() has to be called after changing any variable that could
565 * change the result of the wait condition.
566 *
567 * The function returns 0 if @condition became true, -ERESTARTSYS if it was
568 * interrupted by a signal, or -ETIME if the timeout elapsed.
569 */
570#define wait_event_interruptible_hrtimeout(wq, condition, timeout) \
571({ \
572 long __ret = 0; \
573 might_sleep(); \
574 if (!(condition)) \
575 __ret = __wait_event_hrtimeout(wq, condition, timeout, \
576 TASK_INTERRUPTIBLE); \
577 __ret; \
578})
579
580#define __wait_event_interruptible_exclusive(wq, condition) \
581 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
582 schedule())
583
584#define wait_event_interruptible_exclusive(wq, condition) \
585({ \
586 int __ret = 0; \
587 might_sleep(); \
588 if (!(condition)) \
589 __ret = __wait_event_interruptible_exclusive(wq, condition); \
590 __ret; \
591})
592
593#define __wait_event_killable_exclusive(wq, condition) \
594 ___wait_event(wq, condition, TASK_KILLABLE, 1, 0, \
595 schedule())
596
597#define wait_event_killable_exclusive(wq, condition) \
598({ \
599 int __ret = 0; \
600 might_sleep(); \
601 if (!(condition)) \
602 __ret = __wait_event_killable_exclusive(wq, condition); \
603 __ret; \
604})
605
606
607#define __wait_event_freezable_exclusive(wq, condition) \
608 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
609 freezable_schedule())
610
611#define wait_event_freezable_exclusive(wq, condition) \
612({ \
613 int __ret = 0; \
614 might_sleep(); \
615 if (!(condition)) \
616 __ret = __wait_event_freezable_exclusive(wq, condition); \
617 __ret; \
618})
619
620/**
621 * wait_event_idle - wait for a condition without contributing to system load
622 * @wq_head: the waitqueue to wait on
623 * @condition: a C expression for the event to wait for
624 *
625 * The process is put to sleep (TASK_IDLE) until the
626 * @condition evaluates to true.
627 * The @condition is checked each time the waitqueue @wq_head is woken up.
628 *
629 * wake_up() has to be called after changing any variable that could
630 * change the result of the wait condition.
631 *
632 */
633#define wait_event_idle(wq_head, condition) \
634do { \
635 might_sleep(); \
636 if (!(condition)) \
637 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \
638} while (0)
639
640/**
641 * wait_event_idle_exclusive - wait for a condition with contributing to system load
642 * @wq_head: the waitqueue to wait on
643 * @condition: a C expression for the event to wait for
644 *
645 * The process is put to sleep (TASK_IDLE) until the
646 * @condition evaluates to true.
647 * The @condition is checked each time the waitqueue @wq_head is woken up.
648 *
649 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
650 * set thus if other processes wait on the same list, when this
651 * process is woken further processes are not considered.
652 *
653 * wake_up() has to be called after changing any variable that could
654 * change the result of the wait condition.
655 *
656 */
657#define wait_event_idle_exclusive(wq_head, condition) \
658do { \
659 might_sleep(); \
660 if (!(condition)) \
661 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \
662} while (0)
663
664#define __wait_event_idle_timeout(wq_head, condition, timeout) \
665 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
666 TASK_IDLE, 0, timeout, \
667 __ret = schedule_timeout(__ret))
668
669/**
670 * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses
671 * @wq_head: the waitqueue to wait on
672 * @condition: a C expression for the event to wait for
673 * @timeout: timeout, in jiffies
674 *
675 * The process is put to sleep (TASK_IDLE) until the
676 * @condition evaluates to true. The @condition is checked each time
677 * the waitqueue @wq_head is woken up.
678 *
679 * wake_up() has to be called after changing any variable that could
680 * change the result of the wait condition.
681 *
682 * Returns:
683 * 0 if the @condition evaluated to %false after the @timeout elapsed,
684 * 1 if the @condition evaluated to %true after the @timeout elapsed,
685 * or the remaining jiffies (at least 1) if the @condition evaluated
686 * to %true before the @timeout elapsed.
687 */
688#define wait_event_idle_timeout(wq_head, condition, timeout) \
689({ \
690 long __ret = timeout; \
691 might_sleep(); \
692 if (!___wait_cond_timeout(condition)) \
693 __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \
694 __ret; \
695})
696
697#define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout) \
698 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
699 TASK_IDLE, 1, timeout, \
700 __ret = schedule_timeout(__ret))
701
702/**
703 * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses
704 * @wq_head: the waitqueue to wait on
705 * @condition: a C expression for the event to wait for
706 * @timeout: timeout, in jiffies
707 *
708 * The process is put to sleep (TASK_IDLE) until the
709 * @condition evaluates to true. The @condition is checked each time
710 * the waitqueue @wq_head is woken up.
711 *
712 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
713 * set thus if other processes wait on the same list, when this
714 * process is woken further processes are not considered.
715 *
716 * wake_up() has to be called after changing any variable that could
717 * change the result of the wait condition.
718 *
719 * Returns:
720 * 0 if the @condition evaluated to %false after the @timeout elapsed,
721 * 1 if the @condition evaluated to %true after the @timeout elapsed,
722 * or the remaining jiffies (at least 1) if the @condition evaluated
723 * to %true before the @timeout elapsed.
724 */
725#define wait_event_idle_exclusive_timeout(wq_head, condition, timeout) \
726({ \
727 long __ret = timeout; \
728 might_sleep(); \
729 if (!___wait_cond_timeout(condition)) \
730 __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\
731 __ret; \
732})
733
734extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
735extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
736
737#define __wait_event_interruptible_locked(wq, condition, exclusive, fn) \
738({ \
739 int __ret; \
740 DEFINE_WAIT(__wait); \
741 if (exclusive) \
742 __wait.flags |= WQ_FLAG_EXCLUSIVE; \
743 do { \
744 __ret = fn(&(wq), &__wait); \
745 if (__ret) \
746 break; \
747 } while (!(condition)); \
748 __remove_wait_queue(&(wq), &__wait); \
749 __set_current_state(TASK_RUNNING); \
750 __ret; \
751})
752
753
754/**
755 * wait_event_interruptible_locked - sleep until a condition gets true
756 * @wq: the waitqueue to wait on
757 * @condition: a C expression for the event to wait for
758 *
759 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
760 * @condition evaluates to true or a signal is received.
761 * The @condition is checked each time the waitqueue @wq is woken up.
762 *
763 * It must be called with wq.lock being held. This spinlock is
764 * unlocked while sleeping but @condition testing is done while lock
765 * is held and when this macro exits the lock is held.
766 *
767 * The lock is locked/unlocked using spin_lock()/spin_unlock()
768 * functions which must match the way they are locked/unlocked outside
769 * of this macro.
770 *
771 * wake_up_locked() has to be called after changing any variable that could
772 * change the result of the wait condition.
773 *
774 * The function will return -ERESTARTSYS if it was interrupted by a
775 * signal and 0 if @condition evaluated to true.
776 */
777#define wait_event_interruptible_locked(wq, condition) \
778 ((condition) \
779 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
780
781/**
782 * wait_event_interruptible_locked_irq - sleep until a condition gets true
783 * @wq: the waitqueue to wait on
784 * @condition: a C expression for the event to wait for
785 *
786 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
787 * @condition evaluates to true or a signal is received.
788 * The @condition is checked each time the waitqueue @wq is woken up.
789 *
790 * It must be called with wq.lock being held. This spinlock is
791 * unlocked while sleeping but @condition testing is done while lock
792 * is held and when this macro exits the lock is held.
793 *
794 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
795 * functions which must match the way they are locked/unlocked outside
796 * of this macro.
797 *
798 * wake_up_locked() has to be called after changing any variable that could
799 * change the result of the wait condition.
800 *
801 * The function will return -ERESTARTSYS if it was interrupted by a
802 * signal and 0 if @condition evaluated to true.
803 */
804#define wait_event_interruptible_locked_irq(wq, condition) \
805 ((condition) \
806 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
807
808/**
809 * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
810 * @wq: the waitqueue to wait on
811 * @condition: a C expression for the event to wait for
812 *
813 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
814 * @condition evaluates to true or a signal is received.
815 * The @condition is checked each time the waitqueue @wq is woken up.
816 *
817 * It must be called with wq.lock being held. This spinlock is
818 * unlocked while sleeping but @condition testing is done while lock
819 * is held and when this macro exits the lock is held.
820 *
821 * The lock is locked/unlocked using spin_lock()/spin_unlock()
822 * functions which must match the way they are locked/unlocked outside
823 * of this macro.
824 *
825 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
826 * set thus when other process waits process on the list if this
827 * process is awaken further processes are not considered.
828 *
829 * wake_up_locked() has to be called after changing any variable that could
830 * change the result of the wait condition.
831 *
832 * The function will return -ERESTARTSYS if it was interrupted by a
833 * signal and 0 if @condition evaluated to true.
834 */
835#define wait_event_interruptible_exclusive_locked(wq, condition) \
836 ((condition) \
837 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
838
839/**
840 * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
841 * @wq: the waitqueue to wait on
842 * @condition: a C expression for the event to wait for
843 *
844 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
845 * @condition evaluates to true or a signal is received.
846 * The @condition is checked each time the waitqueue @wq is woken up.
847 *
848 * It must be called with wq.lock being held. This spinlock is
849 * unlocked while sleeping but @condition testing is done while lock
850 * is held and when this macro exits the lock is held.
851 *
852 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
853 * functions which must match the way they are locked/unlocked outside
854 * of this macro.
855 *
856 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
857 * set thus when other process waits process on the list if this
858 * process is awaken further processes are not considered.
859 *
860 * wake_up_locked() has to be called after changing any variable that could
861 * change the result of the wait condition.
862 *
863 * The function will return -ERESTARTSYS if it was interrupted by a
864 * signal and 0 if @condition evaluated to true.
865 */
866#define wait_event_interruptible_exclusive_locked_irq(wq, condition) \
867 ((condition) \
868 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
869
870
871#define __wait_event_killable(wq, condition) \
872 ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
873
874/**
875 * wait_event_killable - sleep until a condition gets true
876 * @wq_head: the waitqueue to wait on
877 * @condition: a C expression for the event to wait for
878 *
879 * The process is put to sleep (TASK_KILLABLE) until the
880 * @condition evaluates to true or a signal is received.
881 * The @condition is checked each time the waitqueue @wq_head is woken up.
882 *
883 * wake_up() has to be called after changing any variable that could
884 * change the result of the wait condition.
885 *
886 * The function will return -ERESTARTSYS if it was interrupted by a
887 * signal and 0 if @condition evaluated to true.
888 */
889#define wait_event_killable(wq_head, condition) \
890({ \
891 int __ret = 0; \
892 might_sleep(); \
893 if (!(condition)) \
894 __ret = __wait_event_killable(wq_head, condition); \
895 __ret; \
896})
897
898#define __wait_event_killable_timeout(wq_head, condition, timeout) \
899 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
900 TASK_KILLABLE, 0, timeout, \
901 __ret = schedule_timeout(__ret))
902
903/**
904 * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
905 * @wq_head: the waitqueue to wait on
906 * @condition: a C expression for the event to wait for
907 * @timeout: timeout, in jiffies
908 *
909 * The process is put to sleep (TASK_KILLABLE) until the
910 * @condition evaluates to true or a kill signal is received.
911 * The @condition is checked each time the waitqueue @wq_head is woken up.
912 *
913 * wake_up() has to be called after changing any variable that could
914 * change the result of the wait condition.
915 *
916 * Returns:
917 * 0 if the @condition evaluated to %false after the @timeout elapsed,
918 * 1 if the @condition evaluated to %true after the @timeout elapsed,
919 * the remaining jiffies (at least 1) if the @condition evaluated
920 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
921 * interrupted by a kill signal.
922 *
923 * Only kill signals interrupt this process.
924 */
925#define wait_event_killable_timeout(wq_head, condition, timeout) \
926({ \
927 long __ret = timeout; \
928 might_sleep(); \
929 if (!___wait_cond_timeout(condition)) \
930 __ret = __wait_event_killable_timeout(wq_head, \
931 condition, timeout); \
932 __ret; \
933})
934
935
936#define __wait_event_lock_irq(wq_head, condition, lock, cmd) \
937 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
938 spin_unlock_irq(&lock); \
939 cmd; \
940 schedule(); \
941 spin_lock_irq(&lock))
942
943/**
944 * wait_event_lock_irq_cmd - sleep until a condition gets true. The
945 * condition is checked under the lock. This
946 * is expected to be called with the lock
947 * taken.
948 * @wq_head: the waitqueue to wait on
949 * @condition: a C expression for the event to wait for
950 * @lock: a locked spinlock_t, which will be released before cmd
951 * and schedule() and reacquired afterwards.
952 * @cmd: a command which is invoked outside the critical section before
953 * sleep
954 *
955 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
956 * @condition evaluates to true. The @condition is checked each time
957 * the waitqueue @wq_head is woken up.
958 *
959 * wake_up() has to be called after changing any variable that could
960 * change the result of the wait condition.
961 *
962 * This is supposed to be called while holding the lock. The lock is
963 * dropped before invoking the cmd and going to sleep and is reacquired
964 * afterwards.
965 */
966#define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd) \
967do { \
968 if (condition) \
969 break; \
970 __wait_event_lock_irq(wq_head, condition, lock, cmd); \
971} while (0)
972
973/**
974 * wait_event_lock_irq - sleep until a condition gets true. The
975 * condition is checked under the lock. This
976 * is expected to be called with the lock
977 * taken.
978 * @wq_head: the waitqueue to wait on
979 * @condition: a C expression for the event to wait for
980 * @lock: a locked spinlock_t, which will be released before schedule()
981 * and reacquired afterwards.
982 *
983 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
984 * @condition evaluates to true. The @condition is checked each time
985 * the waitqueue @wq_head is woken up.
986 *
987 * wake_up() has to be called after changing any variable that could
988 * change the result of the wait condition.
989 *
990 * This is supposed to be called while holding the lock. The lock is
991 * dropped before going to sleep and is reacquired afterwards.
992 */
993#define wait_event_lock_irq(wq_head, condition, lock) \
994do { \
995 if (condition) \
996 break; \
997 __wait_event_lock_irq(wq_head, condition, lock, ); \
998} while (0)
999
1000
1001#define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd) \
1002 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
1003 spin_unlock_irq(&lock); \
1004 cmd; \
1005 schedule(); \
1006 spin_lock_irq(&lock))
1007
1008/**
1009 * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
1010 * The condition is checked under the lock. This is expected to
1011 * be called with the lock taken.
1012 * @wq_head: the waitqueue to wait on
1013 * @condition: a C expression for the event to wait for
1014 * @lock: a locked spinlock_t, which will be released before cmd and
1015 * schedule() and reacquired afterwards.
1016 * @cmd: a command which is invoked outside the critical section before
1017 * sleep
1018 *
1019 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1020 * @condition evaluates to true or a signal is received. The @condition is
1021 * checked each time the waitqueue @wq_head is woken up.
1022 *
1023 * wake_up() has to be called after changing any variable that could
1024 * change the result of the wait condition.
1025 *
1026 * This is supposed to be called while holding the lock. The lock is
1027 * dropped before invoking the cmd and going to sleep and is reacquired
1028 * afterwards.
1029 *
1030 * The macro will return -ERESTARTSYS if it was interrupted by a signal
1031 * and 0 if @condition evaluated to true.
1032 */
1033#define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd) \
1034({ \
1035 int __ret = 0; \
1036 if (!(condition)) \
1037 __ret = __wait_event_interruptible_lock_irq(wq_head, \
1038 condition, lock, cmd); \
1039 __ret; \
1040})
1041
1042/**
1043 * wait_event_interruptible_lock_irq - sleep until a condition gets true.
1044 * The condition is checked under the lock. This is expected
1045 * to be called with the lock taken.
1046 * @wq_head: the waitqueue to wait on
1047 * @condition: a C expression for the event to wait for
1048 * @lock: a locked spinlock_t, which will be released before schedule()
1049 * and reacquired afterwards.
1050 *
1051 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1052 * @condition evaluates to true or signal is received. The @condition is
1053 * checked each time the waitqueue @wq_head is woken up.
1054 *
1055 * wake_up() has to be called after changing any variable that could
1056 * change the result of the wait condition.
1057 *
1058 * This is supposed to be called while holding the lock. The lock is
1059 * dropped before going to sleep and is reacquired afterwards.
1060 *
1061 * The macro will return -ERESTARTSYS if it was interrupted by a signal
1062 * and 0 if @condition evaluated to true.
1063 */
1064#define wait_event_interruptible_lock_irq(wq_head, condition, lock) \
1065({ \
1066 int __ret = 0; \
1067 if (!(condition)) \
1068 __ret = __wait_event_interruptible_lock_irq(wq_head, \
1069 condition, lock,); \
1070 __ret; \
1071})
1072
1073#define __wait_event_lock_irq_timeout(wq_head, condition, lock, timeout, state) \
1074 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
1075 state, 0, timeout, \
1076 spin_unlock_irq(&lock); \
1077 __ret = schedule_timeout(__ret); \
1078 spin_lock_irq(&lock));
1079
1080/**
1081 * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
1082 * true or a timeout elapses. The condition is checked under
1083 * the lock. This is expected to be called with the lock taken.
1084 * @wq_head: the waitqueue to wait on
1085 * @condition: a C expression for the event to wait for
1086 * @lock: a locked spinlock_t, which will be released before schedule()
1087 * and reacquired afterwards.
1088 * @timeout: timeout, in jiffies
1089 *
1090 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1091 * @condition evaluates to true or signal is received. The @condition is
1092 * checked each time the waitqueue @wq_head is woken up.
1093 *
1094 * wake_up() has to be called after changing any variable that could
1095 * change the result of the wait condition.
1096 *
1097 * This is supposed to be called while holding the lock. The lock is
1098 * dropped before going to sleep and is reacquired afterwards.
1099 *
1100 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
1101 * was interrupted by a signal, and the remaining jiffies otherwise
1102 * if the condition evaluated to true before the timeout elapsed.
1103 */
1104#define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock, \
1105 timeout) \
1106({ \
1107 long __ret = timeout; \
1108 if (!___wait_cond_timeout(condition)) \
1109 __ret = __wait_event_lock_irq_timeout( \
1110 wq_head, condition, lock, timeout, \
1111 TASK_INTERRUPTIBLE); \
1112 __ret; \
1113})
1114
1115#define wait_event_lock_irq_timeout(wq_head, condition, lock, timeout) \
1116({ \
1117 long __ret = timeout; \
1118 if (!___wait_cond_timeout(condition)) \
1119 __ret = __wait_event_lock_irq_timeout( \
1120 wq_head, condition, lock, timeout, \
1121 TASK_UNINTERRUPTIBLE); \
1122 __ret; \
1123})
1124
1125/*
1126 * Waitqueues which are removed from the waitqueue_head at wakeup time
1127 */
1128void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1129void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1130long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1131void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
1132long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
1133int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1134int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1135
1136#define DEFINE_WAIT_FUNC(name, function) \
1137 struct wait_queue_entry name = { \
1138 .private = current, \
1139 .func = function, \
1140 .entry = LIST_HEAD_INIT((name).entry), \
1141 }
1142
1143#define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
1144
1145#define init_wait(wait) \
1146 do { \
1147 (wait)->private = current; \
1148 (wait)->func = autoremove_wake_function; \
1149 INIT_LIST_HEAD(&(wait)->entry); \
1150 (wait)->flags = 0; \
1151 } while (0)
1152
1153bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg);
1154
1155#endif /* _LINUX_WAIT_H */
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
13typedef struct wait_queue_entry wait_queue_entry_t;
14
15typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
16int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
17
18/* wait_queue_entry::flags */
19#define WQ_FLAG_EXCLUSIVE 0x01
20#define WQ_FLAG_WOKEN 0x02
21#define WQ_FLAG_CUSTOM 0x04
22#define WQ_FLAG_DONE 0x08
23#define WQ_FLAG_PRIORITY 0x10
24
25/*
26 * A single wait-queue entry structure:
27 */
28struct wait_queue_entry {
29 unsigned int flags;
30 void *private;
31 wait_queue_func_t func;
32 struct list_head entry;
33};
34
35struct wait_queue_head {
36 spinlock_t lock;
37 struct list_head head;
38};
39typedef struct wait_queue_head wait_queue_head_t;
40
41struct task_struct;
42
43/*
44 * Macros for declaration and initialisaton of the datatypes
45 */
46
47#define __WAITQUEUE_INITIALIZER(name, tsk) { \
48 .private = tsk, \
49 .func = default_wake_function, \
50 .entry = { NULL, NULL } }
51
52#define DECLARE_WAITQUEUE(name, tsk) \
53 struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk)
54
55#define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
56 .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
57 .head = LIST_HEAD_INIT(name.head) }
58
59#define DECLARE_WAIT_QUEUE_HEAD(name) \
60 struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
61
62extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
63
64#define init_waitqueue_head(wq_head) \
65 do { \
66 static struct lock_class_key __key; \
67 \
68 __init_waitqueue_head((wq_head), #wq_head, &__key); \
69 } while (0)
70
71#ifdef CONFIG_LOCKDEP
72# define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
73 ({ init_waitqueue_head(&name); name; })
74# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
75 struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
76#else
77# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
78#endif
79
80static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p)
81{
82 wq_entry->flags = 0;
83 wq_entry->private = p;
84 wq_entry->func = default_wake_function;
85}
86
87static inline void
88init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func)
89{
90 wq_entry->flags = 0;
91 wq_entry->private = NULL;
92 wq_entry->func = func;
93}
94
95/**
96 * waitqueue_active -- locklessly test for waiters on the queue
97 * @wq_head: the waitqueue to test for waiters
98 *
99 * returns true if the wait list is not empty
100 *
101 * NOTE: this function is lockless and requires care, incorrect usage _will_
102 * lead to sporadic and non-obvious failure.
103 *
104 * Use either while holding wait_queue_head::lock or when used for wakeups
105 * with an extra smp_mb() like::
106 *
107 * CPU0 - waker CPU1 - waiter
108 *
109 * for (;;) {
110 * @cond = true; prepare_to_wait(&wq_head, &wait, state);
111 * smp_mb(); // smp_mb() from set_current_state()
112 * if (waitqueue_active(wq_head)) if (@cond)
113 * wake_up(wq_head); break;
114 * schedule();
115 * }
116 * finish_wait(&wq_head, &wait);
117 *
118 * Because without the explicit smp_mb() it's possible for the
119 * waitqueue_active() load to get hoisted over the @cond store such that we'll
120 * observe an empty wait list while the waiter might not observe @cond.
121 *
122 * Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
123 * which (when the lock is uncontended) are of roughly equal cost.
124 */
125static inline int waitqueue_active(struct wait_queue_head *wq_head)
126{
127 return !list_empty(&wq_head->head);
128}
129
130/**
131 * wq_has_single_sleeper - check if there is only one sleeper
132 * @wq_head: wait queue head
133 *
134 * Returns true of wq_head has only one sleeper on the list.
135 *
136 * Please refer to the comment for waitqueue_active.
137 */
138static inline bool wq_has_single_sleeper(struct wait_queue_head *wq_head)
139{
140 return list_is_singular(&wq_head->head);
141}
142
143/**
144 * wq_has_sleeper - check if there are any waiting processes
145 * @wq_head: wait queue head
146 *
147 * Returns true if wq_head has waiting processes
148 *
149 * Please refer to the comment for waitqueue_active.
150 */
151static inline bool wq_has_sleeper(struct wait_queue_head *wq_head)
152{
153 /*
154 * We need to be sure we are in sync with the
155 * add_wait_queue modifications to the wait queue.
156 *
157 * This memory barrier should be paired with one on the
158 * waiting side.
159 */
160 smp_mb();
161 return waitqueue_active(wq_head);
162}
163
164extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
165extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
166extern void add_wait_queue_priority(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
167extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
168
169static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
170{
171 struct list_head *head = &wq_head->head;
172 struct wait_queue_entry *wq;
173
174 list_for_each_entry(wq, &wq_head->head, entry) {
175 if (!(wq->flags & WQ_FLAG_PRIORITY))
176 break;
177 head = &wq->entry;
178 }
179 list_add(&wq_entry->entry, head);
180}
181
182/*
183 * Used for wake-one threads:
184 */
185static inline void
186__add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
187{
188 wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
189 __add_wait_queue(wq_head, wq_entry);
190}
191
192static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
193{
194 list_add_tail(&wq_entry->entry, &wq_head->head);
195}
196
197static inline void
198__add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
199{
200 wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
201 __add_wait_queue_entry_tail(wq_head, wq_entry);
202}
203
204static inline void
205__remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
206{
207 list_del(&wq_entry->entry);
208}
209
210int __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
211void __wake_up_on_current_cpu(struct wait_queue_head *wq_head, unsigned int mode, void *key);
212void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
213void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
214void __wake_up_locked_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
215void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
216void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode);
217void __wake_up_pollfree(struct wait_queue_head *wq_head);
218
219#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
220#define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
221#define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
222#define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1)
223#define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0)
224
225#define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
226#define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
227#define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
228#define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE)
229
230/*
231 * Wakeup macros to be used to report events to the targets.
232 */
233#define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m))
234#define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m))
235#define wake_up_poll(x, m) \
236 __wake_up(x, TASK_NORMAL, 1, poll_to_key(m))
237#define wake_up_poll_on_current_cpu(x, m) \
238 __wake_up_on_current_cpu(x, TASK_NORMAL, poll_to_key(m))
239#define wake_up_locked_poll(x, m) \
240 __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m))
241#define wake_up_interruptible_poll(x, m) \
242 __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m))
243#define wake_up_interruptible_sync_poll(x, m) \
244 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m))
245#define wake_up_interruptible_sync_poll_locked(x, m) \
246 __wake_up_locked_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m))
247
248/**
249 * wake_up_pollfree - signal that a polled waitqueue is going away
250 * @wq_head: the wait queue head
251 *
252 * In the very rare cases where a ->poll() implementation uses a waitqueue whose
253 * lifetime is tied to a task rather than to the 'struct file' being polled,
254 * this function must be called before the waitqueue is freed so that
255 * non-blocking polls (e.g. epoll) are notified that the queue is going away.
256 *
257 * The caller must also RCU-delay the freeing of the wait_queue_head, e.g. via
258 * an explicit synchronize_rcu() or call_rcu(), or via SLAB_TYPESAFE_BY_RCU.
259 */
260static inline void wake_up_pollfree(struct wait_queue_head *wq_head)
261{
262 /*
263 * For performance reasons, we don't always take the queue lock here.
264 * Therefore, we might race with someone removing the last entry from
265 * the queue, and proceed while they still hold the queue lock.
266 * However, rcu_read_lock() is required to be held in such cases, so we
267 * can safely proceed with an RCU-delayed free.
268 */
269 if (waitqueue_active(wq_head))
270 __wake_up_pollfree(wq_head);
271}
272
273#define ___wait_cond_timeout(condition) \
274({ \
275 bool __cond = (condition); \
276 if (__cond && !__ret) \
277 __ret = 1; \
278 __cond || !__ret; \
279})
280
281#define ___wait_is_interruptible(state) \
282 (!__builtin_constant_p(state) || \
283 (state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
284
285extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
286
287/*
288 * The below macro ___wait_event() has an explicit shadow of the __ret
289 * variable when used from the wait_event_*() macros.
290 *
291 * This is so that both can use the ___wait_cond_timeout() construct
292 * to wrap the condition.
293 *
294 * The type inconsistency of the wait_event_*() __ret variable is also
295 * on purpose; we use long where we can return timeout values and int
296 * otherwise.
297 */
298
299#define ___wait_event(wq_head, condition, state, exclusive, ret, cmd) \
300({ \
301 __label__ __out; \
302 struct wait_queue_entry __wq_entry; \
303 long __ret = ret; /* explicit shadow */ \
304 \
305 init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \
306 for (;;) { \
307 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
308 \
309 if (condition) \
310 break; \
311 \
312 if (___wait_is_interruptible(state) && __int) { \
313 __ret = __int; \
314 goto __out; \
315 } \
316 \
317 cmd; \
318 } \
319 finish_wait(&wq_head, &__wq_entry); \
320__out: __ret; \
321})
322
323#define __wait_event(wq_head, condition) \
324 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
325 schedule())
326
327/**
328 * wait_event - sleep until a condition gets true
329 * @wq_head: the waitqueue to wait on
330 * @condition: a C expression for the event to wait for
331 *
332 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
333 * @condition evaluates to true. The @condition is checked each time
334 * the waitqueue @wq_head is woken up.
335 *
336 * wake_up() has to be called after changing any variable that could
337 * change the result of the wait condition.
338 */
339#define wait_event(wq_head, condition) \
340do { \
341 might_sleep(); \
342 if (condition) \
343 break; \
344 __wait_event(wq_head, condition); \
345} while (0)
346
347#define __io_wait_event(wq_head, condition) \
348 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
349 io_schedule())
350
351/*
352 * io_wait_event() -- like wait_event() but with io_schedule()
353 */
354#define io_wait_event(wq_head, condition) \
355do { \
356 might_sleep(); \
357 if (condition) \
358 break; \
359 __io_wait_event(wq_head, condition); \
360} while (0)
361
362#define __wait_event_freezable(wq_head, condition) \
363 ___wait_event(wq_head, condition, (TASK_INTERRUPTIBLE|TASK_FREEZABLE), \
364 0, 0, schedule())
365
366/**
367 * wait_event_freezable - sleep (or freeze) until a condition gets true
368 * @wq_head: the waitqueue to wait on
369 * @condition: a C expression for the event to wait for
370 *
371 * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
372 * to system load) until the @condition evaluates to true. The
373 * @condition is checked each time the waitqueue @wq_head is woken up.
374 *
375 * wake_up() has to be called after changing any variable that could
376 * change the result of the wait condition.
377 */
378#define wait_event_freezable(wq_head, condition) \
379({ \
380 int __ret = 0; \
381 might_sleep(); \
382 if (!(condition)) \
383 __ret = __wait_event_freezable(wq_head, condition); \
384 __ret; \
385})
386
387#define __wait_event_timeout(wq_head, condition, timeout) \
388 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
389 TASK_UNINTERRUPTIBLE, 0, timeout, \
390 __ret = schedule_timeout(__ret))
391
392/**
393 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
394 * @wq_head: the waitqueue to wait on
395 * @condition: a C expression for the event to wait for
396 * @timeout: timeout, in jiffies
397 *
398 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
399 * @condition evaluates to true. The @condition is checked each time
400 * the waitqueue @wq_head is woken up.
401 *
402 * wake_up() has to be called after changing any variable that could
403 * change the result of the wait condition.
404 *
405 * Returns:
406 * 0 if the @condition evaluated to %false after the @timeout elapsed,
407 * 1 if the @condition evaluated to %true after the @timeout elapsed,
408 * or the remaining jiffies (at least 1) if the @condition evaluated
409 * to %true before the @timeout elapsed.
410 */
411#define wait_event_timeout(wq_head, condition, timeout) \
412({ \
413 long __ret = timeout; \
414 might_sleep(); \
415 if (!___wait_cond_timeout(condition)) \
416 __ret = __wait_event_timeout(wq_head, condition, timeout); \
417 __ret; \
418})
419
420#define __wait_event_freezable_timeout(wq_head, condition, timeout) \
421 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
422 (TASK_INTERRUPTIBLE|TASK_FREEZABLE), 0, timeout, \
423 __ret = schedule_timeout(__ret))
424
425/*
426 * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
427 * increasing load and is freezable.
428 */
429#define wait_event_freezable_timeout(wq_head, condition, timeout) \
430({ \
431 long __ret = timeout; \
432 might_sleep(); \
433 if (!___wait_cond_timeout(condition)) \
434 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
435 __ret; \
436})
437
438#define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \
439 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0, \
440 cmd1; schedule(); cmd2)
441/*
442 * Just like wait_event_cmd(), except it sets exclusive flag
443 */
444#define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \
445do { \
446 if (condition) \
447 break; \
448 __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2); \
449} while (0)
450
451#define __wait_event_cmd(wq_head, condition, cmd1, cmd2) \
452 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
453 cmd1; schedule(); cmd2)
454
455/**
456 * wait_event_cmd - sleep until a condition gets true
457 * @wq_head: the waitqueue to wait on
458 * @condition: a C expression for the event to wait for
459 * @cmd1: the command will be executed before sleep
460 * @cmd2: the command will be executed after sleep
461 *
462 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
463 * @condition evaluates to true. The @condition is checked each time
464 * the waitqueue @wq_head is woken up.
465 *
466 * wake_up() has to be called after changing any variable that could
467 * change the result of the wait condition.
468 */
469#define wait_event_cmd(wq_head, condition, cmd1, cmd2) \
470do { \
471 if (condition) \
472 break; \
473 __wait_event_cmd(wq_head, condition, cmd1, cmd2); \
474} while (0)
475
476#define __wait_event_interruptible(wq_head, condition) \
477 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
478 schedule())
479
480/**
481 * wait_event_interruptible - sleep until a condition gets true
482 * @wq_head: the waitqueue to wait on
483 * @condition: a C expression for the event to wait for
484 *
485 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
486 * @condition evaluates to true or a signal is received.
487 * The @condition is checked each time the waitqueue @wq_head is woken up.
488 *
489 * wake_up() has to be called after changing any variable that could
490 * change the result of the wait condition.
491 *
492 * The function will return -ERESTARTSYS if it was interrupted by a
493 * signal and 0 if @condition evaluated to true.
494 */
495#define wait_event_interruptible(wq_head, condition) \
496({ \
497 int __ret = 0; \
498 might_sleep(); \
499 if (!(condition)) \
500 __ret = __wait_event_interruptible(wq_head, condition); \
501 __ret; \
502})
503
504#define __wait_event_interruptible_timeout(wq_head, condition, timeout) \
505 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
506 TASK_INTERRUPTIBLE, 0, timeout, \
507 __ret = schedule_timeout(__ret))
508
509/**
510 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
511 * @wq_head: the waitqueue to wait on
512 * @condition: a C expression for the event to wait for
513 * @timeout: timeout, in jiffies
514 *
515 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
516 * @condition evaluates to true or a signal is received.
517 * The @condition is checked each time the waitqueue @wq_head is woken up.
518 *
519 * wake_up() has to be called after changing any variable that could
520 * change the result of the wait condition.
521 *
522 * Returns:
523 * 0 if the @condition evaluated to %false after the @timeout elapsed,
524 * 1 if the @condition evaluated to %true after the @timeout elapsed,
525 * the remaining jiffies (at least 1) if the @condition evaluated
526 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
527 * interrupted by a signal.
528 */
529#define wait_event_interruptible_timeout(wq_head, condition, timeout) \
530({ \
531 long __ret = timeout; \
532 might_sleep(); \
533 if (!___wait_cond_timeout(condition)) \
534 __ret = __wait_event_interruptible_timeout(wq_head, \
535 condition, timeout); \
536 __ret; \
537})
538
539#define __wait_event_hrtimeout(wq_head, condition, timeout, state) \
540({ \
541 int __ret = 0; \
542 struct hrtimer_sleeper __t; \
543 \
544 hrtimer_init_sleeper_on_stack(&__t, CLOCK_MONOTONIC, \
545 HRTIMER_MODE_REL); \
546 if ((timeout) != KTIME_MAX) { \
547 hrtimer_set_expires_range_ns(&__t.timer, timeout, \
548 current->timer_slack_ns); \
549 hrtimer_sleeper_start_expires(&__t, HRTIMER_MODE_REL); \
550 } \
551 \
552 __ret = ___wait_event(wq_head, condition, state, 0, 0, \
553 if (!__t.task) { \
554 __ret = -ETIME; \
555 break; \
556 } \
557 schedule()); \
558 \
559 hrtimer_cancel(&__t.timer); \
560 destroy_hrtimer_on_stack(&__t.timer); \
561 __ret; \
562})
563
564/**
565 * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
566 * @wq_head: the waitqueue to wait on
567 * @condition: a C expression for the event to wait for
568 * @timeout: timeout, as a ktime_t
569 *
570 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
571 * @condition evaluates to true or a signal is received.
572 * The @condition is checked each time the waitqueue @wq_head is woken up.
573 *
574 * wake_up() has to be called after changing any variable that could
575 * change the result of the wait condition.
576 *
577 * The function returns 0 if @condition became true, or -ETIME if the timeout
578 * elapsed.
579 */
580#define wait_event_hrtimeout(wq_head, condition, timeout) \
581({ \
582 int __ret = 0; \
583 might_sleep(); \
584 if (!(condition)) \
585 __ret = __wait_event_hrtimeout(wq_head, condition, timeout, \
586 TASK_UNINTERRUPTIBLE); \
587 __ret; \
588})
589
590/**
591 * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
592 * @wq: the waitqueue to wait on
593 * @condition: a C expression for the event to wait for
594 * @timeout: timeout, as a ktime_t
595 *
596 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
597 * @condition evaluates to true or a signal is received.
598 * The @condition is checked each time the waitqueue @wq is woken up.
599 *
600 * wake_up() has to be called after changing any variable that could
601 * change the result of the wait condition.
602 *
603 * The function returns 0 if @condition became true, -ERESTARTSYS if it was
604 * interrupted by a signal, or -ETIME if the timeout elapsed.
605 */
606#define wait_event_interruptible_hrtimeout(wq, condition, timeout) \
607({ \
608 long __ret = 0; \
609 might_sleep(); \
610 if (!(condition)) \
611 __ret = __wait_event_hrtimeout(wq, condition, timeout, \
612 TASK_INTERRUPTIBLE); \
613 __ret; \
614})
615
616#define __wait_event_interruptible_exclusive(wq, condition) \
617 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
618 schedule())
619
620#define wait_event_interruptible_exclusive(wq, condition) \
621({ \
622 int __ret = 0; \
623 might_sleep(); \
624 if (!(condition)) \
625 __ret = __wait_event_interruptible_exclusive(wq, condition); \
626 __ret; \
627})
628
629#define __wait_event_killable_exclusive(wq, condition) \
630 ___wait_event(wq, condition, TASK_KILLABLE, 1, 0, \
631 schedule())
632
633#define wait_event_killable_exclusive(wq, condition) \
634({ \
635 int __ret = 0; \
636 might_sleep(); \
637 if (!(condition)) \
638 __ret = __wait_event_killable_exclusive(wq, condition); \
639 __ret; \
640})
641
642
643#define __wait_event_freezable_exclusive(wq, condition) \
644 ___wait_event(wq, condition, (TASK_INTERRUPTIBLE|TASK_FREEZABLE), 1, 0,\
645 schedule())
646
647#define wait_event_freezable_exclusive(wq, condition) \
648({ \
649 int __ret = 0; \
650 might_sleep(); \
651 if (!(condition)) \
652 __ret = __wait_event_freezable_exclusive(wq, condition); \
653 __ret; \
654})
655
656/**
657 * wait_event_idle - wait for a condition without contributing to system load
658 * @wq_head: the waitqueue to wait on
659 * @condition: a C expression for the event to wait for
660 *
661 * The process is put to sleep (TASK_IDLE) until the
662 * @condition evaluates to true.
663 * The @condition is checked each time the waitqueue @wq_head is woken up.
664 *
665 * wake_up() has to be called after changing any variable that could
666 * change the result of the wait condition.
667 *
668 */
669#define wait_event_idle(wq_head, condition) \
670do { \
671 might_sleep(); \
672 if (!(condition)) \
673 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \
674} while (0)
675
676/**
677 * wait_event_idle_exclusive - wait for a condition with contributing to system load
678 * @wq_head: the waitqueue to wait on
679 * @condition: a C expression for the event to wait for
680 *
681 * The process is put to sleep (TASK_IDLE) until the
682 * @condition evaluates to true.
683 * The @condition is checked each time the waitqueue @wq_head is woken up.
684 *
685 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
686 * set thus if other processes wait on the same list, when this
687 * process is woken further processes are not considered.
688 *
689 * wake_up() has to be called after changing any variable that could
690 * change the result of the wait condition.
691 *
692 */
693#define wait_event_idle_exclusive(wq_head, condition) \
694do { \
695 might_sleep(); \
696 if (!(condition)) \
697 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \
698} while (0)
699
700#define __wait_event_idle_timeout(wq_head, condition, timeout) \
701 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
702 TASK_IDLE, 0, timeout, \
703 __ret = schedule_timeout(__ret))
704
705/**
706 * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses
707 * @wq_head: the waitqueue to wait on
708 * @condition: a C expression for the event to wait for
709 * @timeout: timeout, in jiffies
710 *
711 * The process is put to sleep (TASK_IDLE) until the
712 * @condition evaluates to true. The @condition is checked each time
713 * the waitqueue @wq_head is woken up.
714 *
715 * wake_up() has to be called after changing any variable that could
716 * change the result of the wait condition.
717 *
718 * Returns:
719 * 0 if the @condition evaluated to %false after the @timeout elapsed,
720 * 1 if the @condition evaluated to %true after the @timeout elapsed,
721 * or the remaining jiffies (at least 1) if the @condition evaluated
722 * to %true before the @timeout elapsed.
723 */
724#define wait_event_idle_timeout(wq_head, condition, timeout) \
725({ \
726 long __ret = timeout; \
727 might_sleep(); \
728 if (!___wait_cond_timeout(condition)) \
729 __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \
730 __ret; \
731})
732
733#define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout) \
734 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
735 TASK_IDLE, 1, timeout, \
736 __ret = schedule_timeout(__ret))
737
738/**
739 * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses
740 * @wq_head: the waitqueue to wait on
741 * @condition: a C expression for the event to wait for
742 * @timeout: timeout, in jiffies
743 *
744 * The process is put to sleep (TASK_IDLE) until the
745 * @condition evaluates to true. The @condition is checked each time
746 * the waitqueue @wq_head is woken up.
747 *
748 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
749 * set thus if other processes wait on the same list, when this
750 * process is woken further processes are not considered.
751 *
752 * wake_up() has to be called after changing any variable that could
753 * change the result of the wait condition.
754 *
755 * Returns:
756 * 0 if the @condition evaluated to %false after the @timeout elapsed,
757 * 1 if the @condition evaluated to %true after the @timeout elapsed,
758 * or the remaining jiffies (at least 1) if the @condition evaluated
759 * to %true before the @timeout elapsed.
760 */
761#define wait_event_idle_exclusive_timeout(wq_head, condition, timeout) \
762({ \
763 long __ret = timeout; \
764 might_sleep(); \
765 if (!___wait_cond_timeout(condition)) \
766 __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\
767 __ret; \
768})
769
770extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
771extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
772
773#define __wait_event_interruptible_locked(wq, condition, exclusive, fn) \
774({ \
775 int __ret; \
776 DEFINE_WAIT(__wait); \
777 if (exclusive) \
778 __wait.flags |= WQ_FLAG_EXCLUSIVE; \
779 do { \
780 __ret = fn(&(wq), &__wait); \
781 if (__ret) \
782 break; \
783 } while (!(condition)); \
784 __remove_wait_queue(&(wq), &__wait); \
785 __set_current_state(TASK_RUNNING); \
786 __ret; \
787})
788
789
790/**
791 * wait_event_interruptible_locked - sleep until a condition gets true
792 * @wq: the waitqueue to wait on
793 * @condition: a C expression for the event to wait for
794 *
795 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
796 * @condition evaluates to true or a signal is received.
797 * The @condition is checked each time the waitqueue @wq is woken up.
798 *
799 * It must be called with wq.lock being held. This spinlock is
800 * unlocked while sleeping but @condition testing is done while lock
801 * is held and when this macro exits the lock is held.
802 *
803 * The lock is locked/unlocked using spin_lock()/spin_unlock()
804 * functions which must match the way they are locked/unlocked outside
805 * of this macro.
806 *
807 * wake_up_locked() has to be called after changing any variable that could
808 * change the result of the wait condition.
809 *
810 * The function will return -ERESTARTSYS if it was interrupted by a
811 * signal and 0 if @condition evaluated to true.
812 */
813#define wait_event_interruptible_locked(wq, condition) \
814 ((condition) \
815 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
816
817/**
818 * wait_event_interruptible_locked_irq - sleep until a condition gets true
819 * @wq: the waitqueue to wait on
820 * @condition: a C expression for the event to wait for
821 *
822 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
823 * @condition evaluates to true or a signal is received.
824 * The @condition is checked each time the waitqueue @wq is woken up.
825 *
826 * It must be called with wq.lock being held. This spinlock is
827 * unlocked while sleeping but @condition testing is done while lock
828 * is held and when this macro exits the lock is held.
829 *
830 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
831 * functions which must match the way they are locked/unlocked outside
832 * of this macro.
833 *
834 * wake_up_locked() has to be called after changing any variable that could
835 * change the result of the wait condition.
836 *
837 * The function will return -ERESTARTSYS if it was interrupted by a
838 * signal and 0 if @condition evaluated to true.
839 */
840#define wait_event_interruptible_locked_irq(wq, condition) \
841 ((condition) \
842 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
843
844/**
845 * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
846 * @wq: the waitqueue to wait on
847 * @condition: a C expression for the event to wait for
848 *
849 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
850 * @condition evaluates to true or a signal is received.
851 * The @condition is checked each time the waitqueue @wq is woken up.
852 *
853 * It must be called with wq.lock being held. This spinlock is
854 * unlocked while sleeping but @condition testing is done while lock
855 * is held and when this macro exits the lock is held.
856 *
857 * The lock is locked/unlocked using spin_lock()/spin_unlock()
858 * functions which must match the way they are locked/unlocked outside
859 * of this macro.
860 *
861 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
862 * set thus when other process waits process on the list if this
863 * process is awaken further processes are not considered.
864 *
865 * wake_up_locked() has to be called after changing any variable that could
866 * change the result of the wait condition.
867 *
868 * The function will return -ERESTARTSYS if it was interrupted by a
869 * signal and 0 if @condition evaluated to true.
870 */
871#define wait_event_interruptible_exclusive_locked(wq, condition) \
872 ((condition) \
873 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
874
875/**
876 * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
877 * @wq: the waitqueue to wait on
878 * @condition: a C expression for the event to wait for
879 *
880 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
881 * @condition evaluates to true or a signal is received.
882 * The @condition is checked each time the waitqueue @wq is woken up.
883 *
884 * It must be called with wq.lock being held. This spinlock is
885 * unlocked while sleeping but @condition testing is done while lock
886 * is held and when this macro exits the lock is held.
887 *
888 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
889 * functions which must match the way they are locked/unlocked outside
890 * of this macro.
891 *
892 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
893 * set thus when other process waits process on the list if this
894 * process is awaken further processes are not considered.
895 *
896 * wake_up_locked() has to be called after changing any variable that could
897 * change the result of the wait condition.
898 *
899 * The function will return -ERESTARTSYS if it was interrupted by a
900 * signal and 0 if @condition evaluated to true.
901 */
902#define wait_event_interruptible_exclusive_locked_irq(wq, condition) \
903 ((condition) \
904 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
905
906
907#define __wait_event_killable(wq, condition) \
908 ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
909
910/**
911 * wait_event_killable - sleep until a condition gets true
912 * @wq_head: the waitqueue to wait on
913 * @condition: a C expression for the event to wait for
914 *
915 * The process is put to sleep (TASK_KILLABLE) until the
916 * @condition evaluates to true or a signal is received.
917 * The @condition is checked each time the waitqueue @wq_head is woken up.
918 *
919 * wake_up() has to be called after changing any variable that could
920 * change the result of the wait condition.
921 *
922 * The function will return -ERESTARTSYS if it was interrupted by a
923 * signal and 0 if @condition evaluated to true.
924 */
925#define wait_event_killable(wq_head, condition) \
926({ \
927 int __ret = 0; \
928 might_sleep(); \
929 if (!(condition)) \
930 __ret = __wait_event_killable(wq_head, condition); \
931 __ret; \
932})
933
934#define __wait_event_state(wq, condition, state) \
935 ___wait_event(wq, condition, state, 0, 0, schedule())
936
937/**
938 * wait_event_state - sleep until a condition gets true
939 * @wq_head: the waitqueue to wait on
940 * @condition: a C expression for the event to wait for
941 * @state: state to sleep in
942 *
943 * The process is put to sleep (@state) until the @condition evaluates to true
944 * or a signal is received (when allowed by @state). The @condition is checked
945 * each time the waitqueue @wq_head is woken up.
946 *
947 * wake_up() has to be called after changing any variable that could
948 * change the result of the wait condition.
949 *
950 * The function will return -ERESTARTSYS if it was interrupted by a signal
951 * (when allowed by @state) and 0 if @condition evaluated to true.
952 */
953#define wait_event_state(wq_head, condition, state) \
954({ \
955 int __ret = 0; \
956 might_sleep(); \
957 if (!(condition)) \
958 __ret = __wait_event_state(wq_head, condition, state); \
959 __ret; \
960})
961
962#define __wait_event_killable_timeout(wq_head, condition, timeout) \
963 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
964 TASK_KILLABLE, 0, timeout, \
965 __ret = schedule_timeout(__ret))
966
967/**
968 * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
969 * @wq_head: the waitqueue to wait on
970 * @condition: a C expression for the event to wait for
971 * @timeout: timeout, in jiffies
972 *
973 * The process is put to sleep (TASK_KILLABLE) until the
974 * @condition evaluates to true or a kill signal is received.
975 * The @condition is checked each time the waitqueue @wq_head is woken up.
976 *
977 * wake_up() has to be called after changing any variable that could
978 * change the result of the wait condition.
979 *
980 * Returns:
981 * 0 if the @condition evaluated to %false after the @timeout elapsed,
982 * 1 if the @condition evaluated to %true after the @timeout elapsed,
983 * the remaining jiffies (at least 1) if the @condition evaluated
984 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
985 * interrupted by a kill signal.
986 *
987 * Only kill signals interrupt this process.
988 */
989#define wait_event_killable_timeout(wq_head, condition, timeout) \
990({ \
991 long __ret = timeout; \
992 might_sleep(); \
993 if (!___wait_cond_timeout(condition)) \
994 __ret = __wait_event_killable_timeout(wq_head, \
995 condition, timeout); \
996 __ret; \
997})
998
999
1000#define __wait_event_lock_irq(wq_head, condition, lock, cmd) \
1001 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
1002 spin_unlock_irq(&lock); \
1003 cmd; \
1004 schedule(); \
1005 spin_lock_irq(&lock))
1006
1007/**
1008 * wait_event_lock_irq_cmd - sleep until a condition gets true. The
1009 * condition is checked under the lock. This
1010 * is expected to be called with the lock
1011 * taken.
1012 * @wq_head: the waitqueue to wait on
1013 * @condition: a C expression for the event to wait for
1014 * @lock: a locked spinlock_t, which will be released before cmd
1015 * and schedule() and reacquired afterwards.
1016 * @cmd: a command which is invoked outside the critical section before
1017 * sleep
1018 *
1019 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
1020 * @condition evaluates to true. The @condition is checked each time
1021 * the waitqueue @wq_head is woken up.
1022 *
1023 * wake_up() has to be called after changing any variable that could
1024 * change the result of the wait condition.
1025 *
1026 * This is supposed to be called while holding the lock. The lock is
1027 * dropped before invoking the cmd and going to sleep and is reacquired
1028 * afterwards.
1029 */
1030#define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd) \
1031do { \
1032 if (condition) \
1033 break; \
1034 __wait_event_lock_irq(wq_head, condition, lock, cmd); \
1035} while (0)
1036
1037/**
1038 * wait_event_lock_irq - sleep until a condition gets true. The
1039 * condition is checked under the lock. This
1040 * is expected to be called with the lock
1041 * taken.
1042 * @wq_head: the waitqueue to wait on
1043 * @condition: a C expression for the event to wait for
1044 * @lock: a locked spinlock_t, which will be released before schedule()
1045 * and reacquired afterwards.
1046 *
1047 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
1048 * @condition evaluates to true. The @condition is checked each time
1049 * the waitqueue @wq_head is woken up.
1050 *
1051 * wake_up() has to be called after changing any variable that could
1052 * change the result of the wait condition.
1053 *
1054 * This is supposed to be called while holding the lock. The lock is
1055 * dropped before going to sleep and is reacquired afterwards.
1056 */
1057#define wait_event_lock_irq(wq_head, condition, lock) \
1058do { \
1059 if (condition) \
1060 break; \
1061 __wait_event_lock_irq(wq_head, condition, lock, ); \
1062} while (0)
1063
1064
1065#define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd) \
1066 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
1067 spin_unlock_irq(&lock); \
1068 cmd; \
1069 schedule(); \
1070 spin_lock_irq(&lock))
1071
1072/**
1073 * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
1074 * The condition is checked under the lock. This is expected to
1075 * be called with the lock taken.
1076 * @wq_head: the waitqueue to wait on
1077 * @condition: a C expression for the event to wait for
1078 * @lock: a locked spinlock_t, which will be released before cmd and
1079 * schedule() and reacquired afterwards.
1080 * @cmd: a command which is invoked outside the critical section before
1081 * sleep
1082 *
1083 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1084 * @condition evaluates to true or a signal is received. The @condition is
1085 * checked each time the waitqueue @wq_head is woken up.
1086 *
1087 * wake_up() has to be called after changing any variable that could
1088 * change the result of the wait condition.
1089 *
1090 * This is supposed to be called while holding the lock. The lock is
1091 * dropped before invoking the cmd and going to sleep and is reacquired
1092 * afterwards.
1093 *
1094 * The macro will return -ERESTARTSYS if it was interrupted by a signal
1095 * and 0 if @condition evaluated to true.
1096 */
1097#define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd) \
1098({ \
1099 int __ret = 0; \
1100 if (!(condition)) \
1101 __ret = __wait_event_interruptible_lock_irq(wq_head, \
1102 condition, lock, cmd); \
1103 __ret; \
1104})
1105
1106/**
1107 * wait_event_interruptible_lock_irq - sleep until a condition gets true.
1108 * The condition is checked under the lock. This is expected
1109 * to be called with the lock taken.
1110 * @wq_head: the waitqueue to wait on
1111 * @condition: a C expression for the event to wait for
1112 * @lock: a locked spinlock_t, which will be released before schedule()
1113 * and reacquired afterwards.
1114 *
1115 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1116 * @condition evaluates to true or signal is received. The @condition is
1117 * checked each time the waitqueue @wq_head is woken up.
1118 *
1119 * wake_up() has to be called after changing any variable that could
1120 * change the result of the wait condition.
1121 *
1122 * This is supposed to be called while holding the lock. The lock is
1123 * dropped before going to sleep and is reacquired afterwards.
1124 *
1125 * The macro will return -ERESTARTSYS if it was interrupted by a signal
1126 * and 0 if @condition evaluated to true.
1127 */
1128#define wait_event_interruptible_lock_irq(wq_head, condition, lock) \
1129({ \
1130 int __ret = 0; \
1131 if (!(condition)) \
1132 __ret = __wait_event_interruptible_lock_irq(wq_head, \
1133 condition, lock,); \
1134 __ret; \
1135})
1136
1137#define __wait_event_lock_irq_timeout(wq_head, condition, lock, timeout, state) \
1138 ___wait_event(wq_head, ___wait_cond_timeout(condition), \
1139 state, 0, timeout, \
1140 spin_unlock_irq(&lock); \
1141 __ret = schedule_timeout(__ret); \
1142 spin_lock_irq(&lock));
1143
1144/**
1145 * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
1146 * true or a timeout elapses. The condition is checked under
1147 * the lock. This is expected to be called with the lock taken.
1148 * @wq_head: the waitqueue to wait on
1149 * @condition: a C expression for the event to wait for
1150 * @lock: a locked spinlock_t, which will be released before schedule()
1151 * and reacquired afterwards.
1152 * @timeout: timeout, in jiffies
1153 *
1154 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1155 * @condition evaluates to true or signal is received. The @condition is
1156 * checked each time the waitqueue @wq_head is woken up.
1157 *
1158 * wake_up() has to be called after changing any variable that could
1159 * change the result of the wait condition.
1160 *
1161 * This is supposed to be called while holding the lock. The lock is
1162 * dropped before going to sleep and is reacquired afterwards.
1163 *
1164 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
1165 * was interrupted by a signal, and the remaining jiffies otherwise
1166 * if the condition evaluated to true before the timeout elapsed.
1167 */
1168#define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock, \
1169 timeout) \
1170({ \
1171 long __ret = timeout; \
1172 if (!___wait_cond_timeout(condition)) \
1173 __ret = __wait_event_lock_irq_timeout( \
1174 wq_head, condition, lock, timeout, \
1175 TASK_INTERRUPTIBLE); \
1176 __ret; \
1177})
1178
1179#define wait_event_lock_irq_timeout(wq_head, condition, lock, timeout) \
1180({ \
1181 long __ret = timeout; \
1182 if (!___wait_cond_timeout(condition)) \
1183 __ret = __wait_event_lock_irq_timeout( \
1184 wq_head, condition, lock, timeout, \
1185 TASK_UNINTERRUPTIBLE); \
1186 __ret; \
1187})
1188
1189/*
1190 * Waitqueues which are removed from the waitqueue_head at wakeup time
1191 */
1192void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1193bool prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1194long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1195void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
1196long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
1197int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1198int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1199
1200#define DEFINE_WAIT_FUNC(name, function) \
1201 struct wait_queue_entry name = { \
1202 .private = current, \
1203 .func = function, \
1204 .entry = LIST_HEAD_INIT((name).entry), \
1205 }
1206
1207#define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
1208
1209#define init_wait(wait) \
1210 do { \
1211 (wait)->private = current; \
1212 (wait)->func = autoremove_wake_function; \
1213 INIT_LIST_HEAD(&(wait)->entry); \
1214 (wait)->flags = 0; \
1215 } while (0)
1216
1217typedef int (*task_call_f)(struct task_struct *p, void *arg);
1218extern int task_call_func(struct task_struct *p, task_call_f func, void *arg);
1219
1220#endif /* _LINUX_WAIT_H */