1 #ifndef _LINUX_WAIT_H
2 #define _LINUX_WAIT_H
3 /*
4 * Linux wait queue related types and methods
5 */
6 #include <linux/list.h>
7 #include <linux/stddef.h>
8 #include <linux/spinlock.h>
9 #include <asm/current.h>
10 #include <uapi/linux/wait.h>
11
12 typedef struct __wait_queue wait_queue_t;
13 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
14 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
15
16 /* __wait_queue::flags */
17 #define WQ_FLAG_EXCLUSIVE 0x01
18 #define WQ_FLAG_WOKEN 0x02
19
20 struct __wait_queue {
21 unsigned int flags;
22 void *private;
23 wait_queue_func_t func;
24 struct list_head task_list;
25 };
26
27 struct wait_bit_key {
28 void *flags;
29 int bit_nr;
30 #define WAIT_ATOMIC_T_BIT_NR -1
31 unsigned long timeout;
32 };
33
34 struct wait_bit_queue {
35 struct wait_bit_key key;
36 wait_queue_t wait;
37 };
38
39 struct __wait_queue_head {
40 spinlock_t lock;
41 struct list_head task_list;
42 };
43 typedef struct __wait_queue_head wait_queue_head_t;
44
45 struct task_struct;
46
47 /*
48 * Macros for declaration and initialisaton of the datatypes
49 */
50
51 #define __WAITQUEUE_INITIALIZER(name, tsk) { \
52 .private = tsk, \
53 .func = default_wake_function, \
54 .task_list = { NULL, NULL } }
55
56 #define DECLARE_WAITQUEUE(name, tsk) \
57 wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
58
59 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
60 .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
61 .task_list = { &(name).task_list, &(name).task_list } }
62
63 #define DECLARE_WAIT_QUEUE_HEAD(name) \
64 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
65
66 #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
67 { .flags = word, .bit_nr = bit, }
68
69 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p) \
70 { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
71
72 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
73
74 #define init_waitqueue_head(q) \
75 do { \
76 static struct lock_class_key __key; \
77 \
78 __init_waitqueue_head((q), #q, &__key); \
79 } while (0)
80
81 #ifdef CONFIG_LOCKDEP
82 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
83 ({ init_waitqueue_head(&name); name; })
84 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
85 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
86 #else
87 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
88 #endif
89
init_waitqueue_entry(wait_queue_t * q,struct task_struct * p)90 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
91 {
92 q->flags = 0;
93 q->private = p;
94 q->func = default_wake_function;
95 }
96
97 static inline void
init_waitqueue_func_entry(wait_queue_t * q,wait_queue_func_t func)98 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
99 {
100 q->flags = 0;
101 q->private = NULL;
102 q->func = func;
103 }
104
waitqueue_active(wait_queue_head_t * q)105 static inline int waitqueue_active(wait_queue_head_t *q)
106 {
107 return !list_empty(&q->task_list);
108 }
109
110 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
111 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
112 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
113
__add_wait_queue(wait_queue_head_t * head,wait_queue_t * new)114 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
115 {
116 list_add(&new->task_list, &head->task_list);
117 }
118
119 /*
120 * Used for wake-one threads:
121 */
122 static inline void
__add_wait_queue_exclusive(wait_queue_head_t * q,wait_queue_t * wait)123 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
124 {
125 wait->flags |= WQ_FLAG_EXCLUSIVE;
126 __add_wait_queue(q, wait);
127 }
128
__add_wait_queue_tail(wait_queue_head_t * head,wait_queue_t * new)129 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
130 wait_queue_t *new)
131 {
132 list_add_tail(&new->task_list, &head->task_list);
133 }
134
135 static inline void
__add_wait_queue_tail_exclusive(wait_queue_head_t * q,wait_queue_t * wait)136 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
137 {
138 wait->flags |= WQ_FLAG_EXCLUSIVE;
139 __add_wait_queue_tail(q, wait);
140 }
141
142 static inline void
__remove_wait_queue(wait_queue_head_t * head,wait_queue_t * old)143 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
144 {
145 list_del(&old->task_list);
146 }
147
148 typedef int wait_bit_action_f(struct wait_bit_key *);
149 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
150 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
151 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
152 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
153 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
154 void __wake_up_bit(wait_queue_head_t *, void *, int);
155 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
156 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
157 void wake_up_bit(void *, int);
158 void wake_up_atomic_t(atomic_t *);
159 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
160 int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
161 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
162 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
163 wait_queue_head_t *bit_waitqueue(void *, int);
164
165 #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
166 #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
167 #define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
168 #define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1)
169 #define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0)
170
171 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
172 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
173 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
174 #define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
175
176 /*
177 * Wakeup macros to be used to report events to the targets.
178 */
179 #define wake_up_poll(x, m) \
180 __wake_up(x, TASK_NORMAL, 1, (void *) (m))
181 #define wake_up_locked_poll(x, m) \
182 __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
183 #define wake_up_interruptible_poll(x, m) \
184 __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
185 #define wake_up_interruptible_sync_poll(x, m) \
186 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
187
188 #define ___wait_cond_timeout(condition) \
189 ({ \
190 bool __cond = (condition); \
191 if (__cond && !__ret) \
192 __ret = 1; \
193 __cond || !__ret; \
194 })
195
196 #define ___wait_is_interruptible(state) \
197 (!__builtin_constant_p(state) || \
198 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \
199
200 /*
201 * The below macro ___wait_event() has an explicit shadow of the __ret
202 * variable when used from the wait_event_*() macros.
203 *
204 * This is so that both can use the ___wait_cond_timeout() construct
205 * to wrap the condition.
206 *
207 * The type inconsistency of the wait_event_*() __ret variable is also
208 * on purpose; we use long where we can return timeout values and int
209 * otherwise.
210 */
211
212 #define ___wait_event(wq, condition, state, exclusive, ret, cmd) \
213 ({ \
214 __label__ __out; \
215 wait_queue_t __wait; \
216 long __ret = ret; /* explicit shadow */ \
217 \
218 INIT_LIST_HEAD(&__wait.task_list); \
219 if (exclusive) \
220 __wait.flags = WQ_FLAG_EXCLUSIVE; \
221 else \
222 __wait.flags = 0; \
223 \
224 for (;;) { \
225 long __int = prepare_to_wait_event(&wq, &__wait, state);\
226 \
227 if (condition) \
228 break; \
229 \
230 if (___wait_is_interruptible(state) && __int) { \
231 __ret = __int; \
232 if (exclusive) { \
233 abort_exclusive_wait(&wq, &__wait, \
234 state, NULL); \
235 goto __out; \
236 } \
237 break; \
238 } \
239 \
240 cmd; \
241 } \
242 finish_wait(&wq, &__wait); \
243 __out: __ret; \
244 })
245
246 #define __wait_event(wq, condition) \
247 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
248 schedule())
249
250 /**
251 * wait_event - sleep until a condition gets true
252 * @wq: the waitqueue to wait on
253 * @condition: a C expression for the event to wait for
254 *
255 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
256 * @condition evaluates to true. The @condition is checked each time
257 * the waitqueue @wq is woken up.
258 *
259 * wake_up() has to be called after changing any variable that could
260 * change the result of the wait condition.
261 */
262 #define wait_event(wq, condition) \
263 do { \
264 if (condition) \
265 break; \
266 __wait_event(wq, condition); \
267 } while (0)
268
269 #define __wait_event_timeout(wq, condition, timeout) \
270 ___wait_event(wq, ___wait_cond_timeout(condition), \
271 TASK_UNINTERRUPTIBLE, 0, timeout, \
272 __ret = schedule_timeout(__ret))
273
274 /**
275 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
276 * @wq: the waitqueue to wait on
277 * @condition: a C expression for the event to wait for
278 * @timeout: timeout, in jiffies
279 *
280 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
281 * @condition evaluates to true. The @condition is checked each time
282 * the waitqueue @wq is woken up.
283 *
284 * wake_up() has to be called after changing any variable that could
285 * change the result of the wait condition.
286 *
287 * Returns:
288 * 0 if the @condition evaluated to %false after the @timeout elapsed,
289 * 1 if the @condition evaluated to %true after the @timeout elapsed,
290 * or the remaining jiffies (at least 1) if the @condition evaluated
291 * to %true before the @timeout elapsed.
292 */
293 #define wait_event_timeout(wq, condition, timeout) \
294 ({ \
295 long __ret = timeout; \
296 if (!___wait_cond_timeout(condition)) \
297 __ret = __wait_event_timeout(wq, condition, timeout); \
298 __ret; \
299 })
300
301 #define __wait_event_cmd(wq, condition, cmd1, cmd2) \
302 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
303 cmd1; schedule(); cmd2)
304
305 /**
306 * wait_event_cmd - sleep until a condition gets true
307 * @wq: the waitqueue to wait on
308 * @condition: a C expression for the event to wait for
309 * @cmd1: the command will be executed before sleep
310 * @cmd2: the command will be executed after sleep
311 *
312 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
313 * @condition evaluates to true. The @condition is checked each time
314 * the waitqueue @wq is woken up.
315 *
316 * wake_up() has to be called after changing any variable that could
317 * change the result of the wait condition.
318 */
319 #define wait_event_cmd(wq, condition, cmd1, cmd2) \
320 do { \
321 if (condition) \
322 break; \
323 __wait_event_cmd(wq, condition, cmd1, cmd2); \
324 } while (0)
325
326 #define __wait_event_interruptible(wq, condition) \
327 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
328 schedule())
329
330 /**
331 * wait_event_interruptible - sleep until a condition gets true
332 * @wq: the waitqueue to wait on
333 * @condition: a C expression for the event to wait for
334 *
335 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
336 * @condition evaluates to true or a signal is received.
337 * The @condition is checked each time the waitqueue @wq is woken up.
338 *
339 * wake_up() has to be called after changing any variable that could
340 * change the result of the wait condition.
341 *
342 * The function will return -ERESTARTSYS if it was interrupted by a
343 * signal and 0 if @condition evaluated to true.
344 */
345 #define wait_event_interruptible(wq, condition) \
346 ({ \
347 int __ret = 0; \
348 if (!(condition)) \
349 __ret = __wait_event_interruptible(wq, condition); \
350 __ret; \
351 })
352
353 #define __wait_event_interruptible_timeout(wq, condition, timeout) \
354 ___wait_event(wq, ___wait_cond_timeout(condition), \
355 TASK_INTERRUPTIBLE, 0, timeout, \
356 __ret = schedule_timeout(__ret))
357
358 /**
359 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
360 * @wq: the waitqueue to wait on
361 * @condition: a C expression for the event to wait for
362 * @timeout: timeout, in jiffies
363 *
364 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
365 * @condition evaluates to true or a signal is received.
366 * The @condition is checked each time the waitqueue @wq is woken up.
367 *
368 * wake_up() has to be called after changing any variable that could
369 * change the result of the wait condition.
370 *
371 * Returns:
372 * 0 if the @condition evaluated to %false after the @timeout elapsed,
373 * 1 if the @condition evaluated to %true after the @timeout elapsed,
374 * the remaining jiffies (at least 1) if the @condition evaluated
375 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
376 * interrupted by a signal.
377 */
378 #define wait_event_interruptible_timeout(wq, condition, timeout) \
379 ({ \
380 long __ret = timeout; \
381 if (!___wait_cond_timeout(condition)) \
382 __ret = __wait_event_interruptible_timeout(wq, \
383 condition, timeout); \
384 __ret; \
385 })
386
387 #define __wait_event_hrtimeout(wq, condition, timeout, state) \
388 ({ \
389 int __ret = 0; \
390 struct hrtimer_sleeper __t; \
391 \
392 hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, \
393 HRTIMER_MODE_REL); \
394 hrtimer_init_sleeper(&__t, current); \
395 if ((timeout).tv64 != KTIME_MAX) \
396 hrtimer_start_range_ns(&__t.timer, timeout, \
397 current->timer_slack_ns, \
398 HRTIMER_MODE_REL); \
399 \
400 __ret = ___wait_event(wq, condition, state, 0, 0, \
401 if (!__t.task) { \
402 __ret = -ETIME; \
403 break; \
404 } \
405 schedule()); \
406 \
407 hrtimer_cancel(&__t.timer); \
408 destroy_hrtimer_on_stack(&__t.timer); \
409 __ret; \
410 })
411
412 /**
413 * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
414 * @wq: the waitqueue to wait on
415 * @condition: a C expression for the event to wait for
416 * @timeout: timeout, as a ktime_t
417 *
418 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
419 * @condition evaluates to true or a signal is received.
420 * The @condition is checked each time the waitqueue @wq is woken up.
421 *
422 * wake_up() has to be called after changing any variable that could
423 * change the result of the wait condition.
424 *
425 * The function returns 0 if @condition became true, or -ETIME if the timeout
426 * elapsed.
427 */
428 #define wait_event_hrtimeout(wq, condition, timeout) \
429 ({ \
430 int __ret = 0; \
431 if (!(condition)) \
432 __ret = __wait_event_hrtimeout(wq, condition, timeout, \
433 TASK_UNINTERRUPTIBLE); \
434 __ret; \
435 })
436
437 /**
438 * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
439 * @wq: the waitqueue to wait on
440 * @condition: a C expression for the event to wait for
441 * @timeout: timeout, as a ktime_t
442 *
443 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
444 * @condition evaluates to true or a signal is received.
445 * The @condition is checked each time the waitqueue @wq is woken up.
446 *
447 * wake_up() has to be called after changing any variable that could
448 * change the result of the wait condition.
449 *
450 * The function returns 0 if @condition became true, -ERESTARTSYS if it was
451 * interrupted by a signal, or -ETIME if the timeout elapsed.
452 */
453 #define wait_event_interruptible_hrtimeout(wq, condition, timeout) \
454 ({ \
455 long __ret = 0; \
456 if (!(condition)) \
457 __ret = __wait_event_hrtimeout(wq, condition, timeout, \
458 TASK_INTERRUPTIBLE); \
459 __ret; \
460 })
461
462 #define __wait_event_interruptible_exclusive(wq, condition) \
463 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
464 schedule())
465
466 #define wait_event_interruptible_exclusive(wq, condition) \
467 ({ \
468 int __ret = 0; \
469 if (!(condition)) \
470 __ret = __wait_event_interruptible_exclusive(wq, condition);\
471 __ret; \
472 })
473
474
475 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
476 ({ \
477 int __ret = 0; \
478 DEFINE_WAIT(__wait); \
479 if (exclusive) \
480 __wait.flags |= WQ_FLAG_EXCLUSIVE; \
481 do { \
482 if (likely(list_empty(&__wait.task_list))) \
483 __add_wait_queue_tail(&(wq), &__wait); \
484 set_current_state(TASK_INTERRUPTIBLE); \
485 if (signal_pending(current)) { \
486 __ret = -ERESTARTSYS; \
487 break; \
488 } \
489 if (irq) \
490 spin_unlock_irq(&(wq).lock); \
491 else \
492 spin_unlock(&(wq).lock); \
493 schedule(); \
494 if (irq) \
495 spin_lock_irq(&(wq).lock); \
496 else \
497 spin_lock(&(wq).lock); \
498 } while (!(condition)); \
499 __remove_wait_queue(&(wq), &__wait); \
500 __set_current_state(TASK_RUNNING); \
501 __ret; \
502 })
503
504
505 /**
506 * wait_event_interruptible_locked - sleep until a condition gets true
507 * @wq: the waitqueue to wait on
508 * @condition: a C expression for the event to wait for
509 *
510 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
511 * @condition evaluates to true or a signal is received.
512 * The @condition is checked each time the waitqueue @wq is woken up.
513 *
514 * It must be called with wq.lock being held. This spinlock is
515 * unlocked while sleeping but @condition testing is done while lock
516 * is held and when this macro exits the lock is held.
517 *
518 * The lock is locked/unlocked using spin_lock()/spin_unlock()
519 * functions which must match the way they are locked/unlocked outside
520 * of this macro.
521 *
522 * wake_up_locked() has to be called after changing any variable that could
523 * change the result of the wait condition.
524 *
525 * The function will return -ERESTARTSYS if it was interrupted by a
526 * signal and 0 if @condition evaluated to true.
527 */
528 #define wait_event_interruptible_locked(wq, condition) \
529 ((condition) \
530 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
531
532 /**
533 * wait_event_interruptible_locked_irq - sleep until a condition gets true
534 * @wq: the waitqueue to wait on
535 * @condition: a C expression for the event to wait for
536 *
537 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
538 * @condition evaluates to true or a signal is received.
539 * The @condition is checked each time the waitqueue @wq is woken up.
540 *
541 * It must be called with wq.lock being held. This spinlock is
542 * unlocked while sleeping but @condition testing is done while lock
543 * is held and when this macro exits the lock is held.
544 *
545 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
546 * functions which must match the way they are locked/unlocked outside
547 * of this macro.
548 *
549 * wake_up_locked() has to be called after changing any variable that could
550 * change the result of the wait condition.
551 *
552 * The function will return -ERESTARTSYS if it was interrupted by a
553 * signal and 0 if @condition evaluated to true.
554 */
555 #define wait_event_interruptible_locked_irq(wq, condition) \
556 ((condition) \
557 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
558
559 /**
560 * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
561 * @wq: the waitqueue to wait on
562 * @condition: a C expression for the event to wait for
563 *
564 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
565 * @condition evaluates to true or a signal is received.
566 * The @condition is checked each time the waitqueue @wq is woken up.
567 *
568 * It must be called with wq.lock being held. This spinlock is
569 * unlocked while sleeping but @condition testing is done while lock
570 * is held and when this macro exits the lock is held.
571 *
572 * The lock is locked/unlocked using spin_lock()/spin_unlock()
573 * functions which must match the way they are locked/unlocked outside
574 * of this macro.
575 *
576 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
577 * set thus when other process waits process on the list if this
578 * process is awaken further processes are not considered.
579 *
580 * wake_up_locked() has to be called after changing any variable that could
581 * change the result of the wait condition.
582 *
583 * The function will return -ERESTARTSYS if it was interrupted by a
584 * signal and 0 if @condition evaluated to true.
585 */
586 #define wait_event_interruptible_exclusive_locked(wq, condition) \
587 ((condition) \
588 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
589
590 /**
591 * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
592 * @wq: the waitqueue to wait on
593 * @condition: a C expression for the event to wait for
594 *
595 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
596 * @condition evaluates to true or a signal is received.
597 * The @condition is checked each time the waitqueue @wq is woken up.
598 *
599 * It must be called with wq.lock being held. This spinlock is
600 * unlocked while sleeping but @condition testing is done while lock
601 * is held and when this macro exits the lock is held.
602 *
603 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
604 * functions which must match the way they are locked/unlocked outside
605 * of this macro.
606 *
607 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
608 * set thus when other process waits process on the list if this
609 * process is awaken further processes are not considered.
610 *
611 * wake_up_locked() has to be called after changing any variable that could
612 * change the result of the wait condition.
613 *
614 * The function will return -ERESTARTSYS if it was interrupted by a
615 * signal and 0 if @condition evaluated to true.
616 */
617 #define wait_event_interruptible_exclusive_locked_irq(wq, condition) \
618 ((condition) \
619 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
620
621
622 #define __wait_event_killable(wq, condition) \
623 ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
624
625 /**
626 * wait_event_killable - sleep until a condition gets true
627 * @wq: the waitqueue to wait on
628 * @condition: a C expression for the event to wait for
629 *
630 * The process is put to sleep (TASK_KILLABLE) until the
631 * @condition evaluates to true or a signal is received.
632 * The @condition is checked each time the waitqueue @wq is woken up.
633 *
634 * wake_up() has to be called after changing any variable that could
635 * change the result of the wait condition.
636 *
637 * The function will return -ERESTARTSYS if it was interrupted by a
638 * signal and 0 if @condition evaluated to true.
639 */
640 #define wait_event_killable(wq, condition) \
641 ({ \
642 int __ret = 0; \
643 if (!(condition)) \
644 __ret = __wait_event_killable(wq, condition); \
645 __ret; \
646 })
647
648
649 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
650 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
651 spin_unlock_irq(&lock); \
652 cmd; \
653 schedule(); \
654 spin_lock_irq(&lock))
655
656 /**
657 * wait_event_lock_irq_cmd - sleep until a condition gets true. The
658 * condition is checked under the lock. This
659 * is expected to be called with the lock
660 * taken.
661 * @wq: the waitqueue to wait on
662 * @condition: a C expression for the event to wait for
663 * @lock: a locked spinlock_t, which will be released before cmd
664 * and schedule() and reacquired afterwards.
665 * @cmd: a command which is invoked outside the critical section before
666 * sleep
667 *
668 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
669 * @condition evaluates to true. The @condition is checked each time
670 * the waitqueue @wq is woken up.
671 *
672 * wake_up() has to be called after changing any variable that could
673 * change the result of the wait condition.
674 *
675 * This is supposed to be called while holding the lock. The lock is
676 * dropped before invoking the cmd and going to sleep and is reacquired
677 * afterwards.
678 */
679 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd) \
680 do { \
681 if (condition) \
682 break; \
683 __wait_event_lock_irq(wq, condition, lock, cmd); \
684 } while (0)
685
686 /**
687 * wait_event_lock_irq - sleep until a condition gets true. The
688 * condition is checked under the lock. This
689 * is expected to be called with the lock
690 * taken.
691 * @wq: the waitqueue to wait on
692 * @condition: a C expression for the event to wait for
693 * @lock: a locked spinlock_t, which will be released before schedule()
694 * and reacquired afterwards.
695 *
696 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
697 * @condition evaluates to true. The @condition is checked each time
698 * the waitqueue @wq is woken up.
699 *
700 * wake_up() has to be called after changing any variable that could
701 * change the result of the wait condition.
702 *
703 * This is supposed to be called while holding the lock. The lock is
704 * dropped before going to sleep and is reacquired afterwards.
705 */
706 #define wait_event_lock_irq(wq, condition, lock) \
707 do { \
708 if (condition) \
709 break; \
710 __wait_event_lock_irq(wq, condition, lock, ); \
711 } while (0)
712
713
714 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd) \
715 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
716 spin_unlock_irq(&lock); \
717 cmd; \
718 schedule(); \
719 spin_lock_irq(&lock))
720
721 /**
722 * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
723 * The condition is checked under the lock. This is expected to
724 * be called with the lock taken.
725 * @wq: the waitqueue to wait on
726 * @condition: a C expression for the event to wait for
727 * @lock: a locked spinlock_t, which will be released before cmd and
728 * schedule() and reacquired afterwards.
729 * @cmd: a command which is invoked outside the critical section before
730 * sleep
731 *
732 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
733 * @condition evaluates to true or a signal is received. The @condition is
734 * checked each time the waitqueue @wq is woken up.
735 *
736 * wake_up() has to be called after changing any variable that could
737 * change the result of the wait condition.
738 *
739 * This is supposed to be called while holding the lock. The lock is
740 * dropped before invoking the cmd and going to sleep and is reacquired
741 * afterwards.
742 *
743 * The macro will return -ERESTARTSYS if it was interrupted by a signal
744 * and 0 if @condition evaluated to true.
745 */
746 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
747 ({ \
748 int __ret = 0; \
749 if (!(condition)) \
750 __ret = __wait_event_interruptible_lock_irq(wq, \
751 condition, lock, cmd); \
752 __ret; \
753 })
754
755 /**
756 * wait_event_interruptible_lock_irq - sleep until a condition gets true.
757 * The condition is checked under the lock. This is expected
758 * to be called with the lock taken.
759 * @wq: the waitqueue to wait on
760 * @condition: a C expression for the event to wait for
761 * @lock: a locked spinlock_t, which will be released before schedule()
762 * and reacquired afterwards.
763 *
764 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
765 * @condition evaluates to true or signal is received. The @condition is
766 * checked each time the waitqueue @wq is woken up.
767 *
768 * wake_up() has to be called after changing any variable that could
769 * change the result of the wait condition.
770 *
771 * This is supposed to be called while holding the lock. The lock is
772 * dropped before going to sleep and is reacquired afterwards.
773 *
774 * The macro will return -ERESTARTSYS if it was interrupted by a signal
775 * and 0 if @condition evaluated to true.
776 */
777 #define wait_event_interruptible_lock_irq(wq, condition, lock) \
778 ({ \
779 int __ret = 0; \
780 if (!(condition)) \
781 __ret = __wait_event_interruptible_lock_irq(wq, \
782 condition, lock,); \
783 __ret; \
784 })
785
786 #define __wait_event_interruptible_lock_irq_timeout(wq, condition, \
787 lock, timeout) \
788 ___wait_event(wq, ___wait_cond_timeout(condition), \
789 TASK_INTERRUPTIBLE, 0, timeout, \
790 spin_unlock_irq(&lock); \
791 __ret = schedule_timeout(__ret); \
792 spin_lock_irq(&lock));
793
794 /**
795 * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
796 * true or a timeout elapses. The condition is checked under
797 * the lock. This is expected to be called with the lock taken.
798 * @wq: the waitqueue to wait on
799 * @condition: a C expression for the event to wait for
800 * @lock: a locked spinlock_t, which will be released before schedule()
801 * and reacquired afterwards.
802 * @timeout: timeout, in jiffies
803 *
804 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
805 * @condition evaluates to true or signal is received. The @condition is
806 * checked each time the waitqueue @wq is woken up.
807 *
808 * wake_up() has to be called after changing any variable that could
809 * change the result of the wait condition.
810 *
811 * This is supposed to be called while holding the lock. The lock is
812 * dropped before going to sleep and is reacquired afterwards.
813 *
814 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
815 * was interrupted by a signal, and the remaining jiffies otherwise
816 * if the condition evaluated to true before the timeout elapsed.
817 */
818 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock, \
819 timeout) \
820 ({ \
821 long __ret = timeout; \
822 if (!___wait_cond_timeout(condition)) \
823 __ret = __wait_event_interruptible_lock_irq_timeout( \
824 wq, condition, lock, timeout); \
825 __ret; \
826 })
827
828 /*
829 * Waitqueues which are removed from the waitqueue_head at wakeup time
830 */
831 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
832 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
833 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
834 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
835 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
836 long wait_woken(wait_queue_t *wait, unsigned mode, long timeout);
837 int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
838 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
839 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
840
841 #define DEFINE_WAIT_FUNC(name, function) \
842 wait_queue_t name = { \
843 .private = current, \
844 .func = function, \
845 .task_list = LIST_HEAD_INIT((name).task_list), \
846 }
847
848 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
849
850 #define DEFINE_WAIT_BIT(name, word, bit) \
851 struct wait_bit_queue name = { \
852 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
853 .wait = { \
854 .private = current, \
855 .func = wake_bit_function, \
856 .task_list = \
857 LIST_HEAD_INIT((name).wait.task_list), \
858 }, \
859 }
860
861 #define init_wait(wait) \
862 do { \
863 (wait)->private = current; \
864 (wait)->func = autoremove_wake_function; \
865 INIT_LIST_HEAD(&(wait)->task_list); \
866 (wait)->flags = 0; \
867 } while (0)
868
869
870 extern int bit_wait(struct wait_bit_key *);
871 extern int bit_wait_io(struct wait_bit_key *);
872 extern int bit_wait_timeout(struct wait_bit_key *);
873 extern int bit_wait_io_timeout(struct wait_bit_key *);
874
875 /**
876 * wait_on_bit - wait for a bit to be cleared
877 * @word: the word being waited on, a kernel virtual address
878 * @bit: the bit of the word being waited on
879 * @mode: the task state to sleep in
880 *
881 * There is a standard hashed waitqueue table for generic use. This
882 * is the part of the hashtable's accessor API that waits on a bit.
883 * For instance, if one were to have waiters on a bitflag, one would
884 * call wait_on_bit() in threads waiting for the bit to clear.
885 * One uses wait_on_bit() where one is waiting for the bit to clear,
886 * but has no intention of setting it.
887 * Returned value will be zero if the bit was cleared, or non-zero
888 * if the process received a signal and the mode permitted wakeup
889 * on that signal.
890 */
891 static inline int
wait_on_bit(void * word,int bit,unsigned mode)892 wait_on_bit(void *word, int bit, unsigned mode)
893 {
894 if (!test_bit(bit, word))
895 return 0;
896 return out_of_line_wait_on_bit(word, bit,
897 bit_wait,
898 mode);
899 }
900
901 /**
902 * wait_on_bit_io - wait for a bit to be cleared
903 * @word: the word being waited on, a kernel virtual address
904 * @bit: the bit of the word being waited on
905 * @mode: the task state to sleep in
906 *
907 * Use the standard hashed waitqueue table to wait for a bit
908 * to be cleared. This is similar to wait_on_bit(), but calls
909 * io_schedule() instead of schedule() for the actual waiting.
910 *
911 * Returned value will be zero if the bit was cleared, or non-zero
912 * if the process received a signal and the mode permitted wakeup
913 * on that signal.
914 */
915 static inline int
wait_on_bit_io(void * word,int bit,unsigned mode)916 wait_on_bit_io(void *word, int bit, unsigned mode)
917 {
918 if (!test_bit(bit, word))
919 return 0;
920 return out_of_line_wait_on_bit(word, bit,
921 bit_wait_io,
922 mode);
923 }
924
925 /**
926 * wait_on_bit_action - wait for a bit to be cleared
927 * @word: the word being waited on, a kernel virtual address
928 * @bit: the bit of the word being waited on
929 * @action: the function used to sleep, which may take special actions
930 * @mode: the task state to sleep in
931 *
932 * Use the standard hashed waitqueue table to wait for a bit
933 * to be cleared, and allow the waiting action to be specified.
934 * This is like wait_on_bit() but allows fine control of how the waiting
935 * is done.
936 *
937 * Returned value will be zero if the bit was cleared, or non-zero
938 * if the process received a signal and the mode permitted wakeup
939 * on that signal.
940 */
941 static inline int
wait_on_bit_action(void * word,int bit,wait_bit_action_f * action,unsigned mode)942 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
943 {
944 if (!test_bit(bit, word))
945 return 0;
946 return out_of_line_wait_on_bit(word, bit, action, mode);
947 }
948
949 /**
950 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
951 * @word: the word being waited on, a kernel virtual address
952 * @bit: the bit of the word being waited on
953 * @mode: the task state to sleep in
954 *
955 * There is a standard hashed waitqueue table for generic use. This
956 * is the part of the hashtable's accessor API that waits on a bit
957 * when one intends to set it, for instance, trying to lock bitflags.
958 * For instance, if one were to have waiters trying to set bitflag
959 * and waiting for it to clear before setting it, one would call
960 * wait_on_bit() in threads waiting to be able to set the bit.
961 * One uses wait_on_bit_lock() where one is waiting for the bit to
962 * clear with the intention of setting it, and when done, clearing it.
963 *
964 * Returns zero if the bit was (eventually) found to be clear and was
965 * set. Returns non-zero if a signal was delivered to the process and
966 * the @mode allows that signal to wake the process.
967 */
968 static inline int
wait_on_bit_lock(void * word,int bit,unsigned mode)969 wait_on_bit_lock(void *word, int bit, unsigned mode)
970 {
971 if (!test_and_set_bit(bit, word))
972 return 0;
973 return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
974 }
975
976 /**
977 * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
978 * @word: the word being waited on, a kernel virtual address
979 * @bit: the bit of the word being waited on
980 * @mode: the task state to sleep in
981 *
982 * Use the standard hashed waitqueue table to wait for a bit
983 * to be cleared and then to atomically set it. This is similar
984 * to wait_on_bit(), but calls io_schedule() instead of schedule()
985 * for the actual waiting.
986 *
987 * Returns zero if the bit was (eventually) found to be clear and was
988 * set. Returns non-zero if a signal was delivered to the process and
989 * the @mode allows that signal to wake the process.
990 */
991 static inline int
wait_on_bit_lock_io(void * word,int bit,unsigned mode)992 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
993 {
994 if (!test_and_set_bit(bit, word))
995 return 0;
996 return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
997 }
998
999 /**
1000 * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
1001 * @word: the word being waited on, a kernel virtual address
1002 * @bit: the bit of the word being waited on
1003 * @action: the function used to sleep, which may take special actions
1004 * @mode: the task state to sleep in
1005 *
1006 * Use the standard hashed waitqueue table to wait for a bit
1007 * to be cleared and then to set it, and allow the waiting action
1008 * to be specified.
1009 * This is like wait_on_bit() but allows fine control of how the waiting
1010 * is done.
1011 *
1012 * Returns zero if the bit was (eventually) found to be clear and was
1013 * set. Returns non-zero if a signal was delivered to the process and
1014 * the @mode allows that signal to wake the process.
1015 */
1016 static inline int
wait_on_bit_lock_action(void * word,int bit,wait_bit_action_f * action,unsigned mode)1017 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1018 {
1019 if (!test_and_set_bit(bit, word))
1020 return 0;
1021 return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1022 }
1023
1024 /**
1025 * wait_on_atomic_t - Wait for an atomic_t to become 0
1026 * @val: The atomic value being waited on, a kernel virtual address
1027 * @action: the function used to sleep, which may take special actions
1028 * @mode: the task state to sleep in
1029 *
1030 * Wait for an atomic_t to become 0. We abuse the bit-wait waitqueue table for
1031 * the purpose of getting a waitqueue, but we set the key to a bit number
1032 * outside of the target 'word'.
1033 */
1034 static inline
wait_on_atomic_t(atomic_t * val,int (* action)(atomic_t *),unsigned mode)1035 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1036 {
1037 if (atomic_read(val) == 0)
1038 return 0;
1039 return out_of_line_wait_on_atomic_t(val, action, mode);
1040 }
1041
1042 #endif /* _LINUX_WAIT_H */
1043