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1 #ifndef _LINUX_WAIT_H
2 #define _LINUX_WAIT_H
3 
4 #define WNOHANG		0x00000001
5 #define WUNTRACED	0x00000002
6 #define WSTOPPED	WUNTRACED
7 #define WEXITED		0x00000004
8 #define WCONTINUED	0x00000008
9 #define WNOWAIT		0x01000000	/* Don't reap, just poll status.  */
10 
11 #define __WNOTHREAD	0x20000000	/* Don't wait on children of other threads in this group */
12 #define __WALL		0x40000000	/* Wait on all children, regardless of type */
13 #define __WCLONE	0x80000000	/* Wait only on non-SIGCHLD children */
14 
15 /* First argument to waitid: */
16 #define P_ALL		0
17 #define P_PID		1
18 #define P_PGID		2
19 
20 #ifdef __KERNEL__
21 
22 #include <linux/list.h>
23 #include <linux/stddef.h>
24 #include <linux/spinlock.h>
25 #include <asm/current.h>
26 
27 typedef struct __wait_queue wait_queue_t;
28 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
29 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
30 
31 struct __wait_queue {
32 	unsigned int flags;
33 #define WQ_FLAG_EXCLUSIVE	0x01
34 	void *private;
35 	wait_queue_func_t func;
36 	struct list_head task_list;
37 };
38 
39 struct wait_bit_key {
40 	void *flags;
41 	int bit_nr;
42 };
43 
44 struct wait_bit_queue {
45 	struct wait_bit_key key;
46 	wait_queue_t wait;
47 };
48 
49 struct __wait_queue_head {
50 	spinlock_t lock;
51 	struct list_head task_list;
52 };
53 typedef struct __wait_queue_head wait_queue_head_t;
54 
55 struct task_struct;
56 
57 /*
58  * Macros for declaration and initialisaton of the datatypes
59  */
60 
61 #define __WAITQUEUE_INITIALIZER(name, tsk) {				\
62 	.private	= tsk,						\
63 	.func		= default_wake_function,			\
64 	.task_list	= { NULL, NULL } }
65 
66 #define DECLARE_WAITQUEUE(name, tsk)					\
67 	wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
68 
69 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {				\
70 	.lock		= __SPIN_LOCK_UNLOCKED(name.lock),		\
71 	.task_list	= { &(name).task_list, &(name).task_list } }
72 
73 #define DECLARE_WAIT_QUEUE_HEAD(name) \
74 	wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
75 
76 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)				\
77 	{ .flags = word, .bit_nr = bit, }
78 
79 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
80 
81 #define init_waitqueue_head(q)				\
82 	do {						\
83 		static struct lock_class_key __key;	\
84 							\
85 		__init_waitqueue_head((q), #q, &__key);	\
86 	} while (0)
87 
88 #ifdef CONFIG_LOCKDEP
89 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
90 	({ init_waitqueue_head(&name); name; })
91 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
92 	wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
93 #else
94 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
95 #endif
96 
init_waitqueue_entry(wait_queue_t * q,struct task_struct * p)97 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
98 {
99 	q->flags = 0;
100 	q->private = p;
101 	q->func = default_wake_function;
102 }
103 
init_waitqueue_func_entry(wait_queue_t * q,wait_queue_func_t func)104 static inline void init_waitqueue_func_entry(wait_queue_t *q,
105 					wait_queue_func_t func)
106 {
107 	q->flags = 0;
108 	q->private = NULL;
109 	q->func = func;
110 }
111 
waitqueue_active(wait_queue_head_t * q)112 static inline int waitqueue_active(wait_queue_head_t *q)
113 {
114 	return !list_empty(&q->task_list);
115 }
116 
117 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
118 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
119 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
120 
__add_wait_queue(wait_queue_head_t * head,wait_queue_t * new)121 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
122 {
123 	list_add(&new->task_list, &head->task_list);
124 }
125 
126 /*
127  * Used for wake-one threads:
128  */
__add_wait_queue_exclusive(wait_queue_head_t * q,wait_queue_t * wait)129 static inline void __add_wait_queue_exclusive(wait_queue_head_t *q,
130 					      wait_queue_t *wait)
131 {
132 	wait->flags |= WQ_FLAG_EXCLUSIVE;
133 	__add_wait_queue(q, wait);
134 }
135 
__add_wait_queue_tail(wait_queue_head_t * head,wait_queue_t * new)136 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
137 					 wait_queue_t *new)
138 {
139 	list_add_tail(&new->task_list, &head->task_list);
140 }
141 
__add_wait_queue_tail_exclusive(wait_queue_head_t * q,wait_queue_t * wait)142 static inline void __add_wait_queue_tail_exclusive(wait_queue_head_t *q,
143 					      wait_queue_t *wait)
144 {
145 	wait->flags |= WQ_FLAG_EXCLUSIVE;
146 	__add_wait_queue_tail(q, wait);
147 }
148 
__remove_wait_queue(wait_queue_head_t * head,wait_queue_t * old)149 static inline void __remove_wait_queue(wait_queue_head_t *head,
150 							wait_queue_t *old)
151 {
152 	list_del(&old->task_list);
153 }
154 
155 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
156 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
157 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
158 			void *key);
159 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
160 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
161 void __wake_up_bit(wait_queue_head_t *, void *, int);
162 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
163 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
164 void wake_up_bit(void *, int);
165 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
166 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
167 wait_queue_head_t *bit_waitqueue(void *, int);
168 
169 #define wake_up(x)			__wake_up(x, TASK_NORMAL, 1, NULL)
170 #define wake_up_nr(x, nr)		__wake_up(x, TASK_NORMAL, nr, NULL)
171 #define wake_up_all(x)			__wake_up(x, TASK_NORMAL, 0, NULL)
172 #define wake_up_locked(x)		__wake_up_locked((x), TASK_NORMAL, 1)
173 #define wake_up_all_locked(x)		__wake_up_locked((x), TASK_NORMAL, 0)
174 
175 #define wake_up_interruptible(x)	__wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
176 #define wake_up_interruptible_nr(x, nr)	__wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
177 #define wake_up_interruptible_all(x)	__wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
178 #define wake_up_interruptible_sync(x)	__wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
179 
180 /*
181  * Wakeup macros to be used to report events to the targets.
182  */
183 #define wake_up_poll(x, m)				\
184 	__wake_up(x, TASK_NORMAL, 1, (void *) (m))
185 #define wake_up_locked_poll(x, m)				\
186 	__wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
187 #define wake_up_interruptible_poll(x, m)			\
188 	__wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
189 #define wake_up_interruptible_sync_poll(x, m)				\
190 	__wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
191 
192 #define __wait_event(wq, condition) 					\
193 do {									\
194 	DEFINE_WAIT(__wait);						\
195 									\
196 	for (;;) {							\
197 		prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);	\
198 		if (condition)						\
199 			break;						\
200 		schedule();						\
201 	}								\
202 	finish_wait(&wq, &__wait);					\
203 } while (0)
204 
205 /**
206  * wait_event - sleep until a condition gets true
207  * @wq: the waitqueue to wait on
208  * @condition: a C expression for the event to wait for
209  *
210  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
211  * @condition evaluates to true. The @condition is checked each time
212  * the waitqueue @wq is woken up.
213  *
214  * wake_up() has to be called after changing any variable that could
215  * change the result of the wait condition.
216  */
217 #define wait_event(wq, condition) 					\
218 do {									\
219 	if (condition)	 						\
220 		break;							\
221 	__wait_event(wq, condition);					\
222 } while (0)
223 
224 #define __wait_event_timeout(wq, condition, ret)			\
225 do {									\
226 	DEFINE_WAIT(__wait);						\
227 									\
228 	for (;;) {							\
229 		prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);	\
230 		if (condition)						\
231 			break;						\
232 		ret = schedule_timeout(ret);				\
233 		if (!ret)						\
234 			break;						\
235 	}								\
236 	if (!ret && (condition))					\
237 		ret = 1;						\
238 	finish_wait(&wq, &__wait);					\
239 } while (0)
240 
241 /**
242  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
243  * @wq: the waitqueue to wait on
244  * @condition: a C expression for the event to wait for
245  * @timeout: timeout, in jiffies
246  *
247  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
248  * @condition evaluates to true. The @condition is checked each time
249  * the waitqueue @wq is woken up.
250  *
251  * wake_up() has to be called after changing any variable that could
252  * change the result of the wait condition.
253  *
254  * The function returns 0 if the @timeout elapsed, or the remaining
255  * jiffies (at least 1) if the @condition evaluated to %true before
256  * the @timeout elapsed.
257  */
258 #define wait_event_timeout(wq, condition, timeout)			\
259 ({									\
260 	long __ret = timeout;						\
261 	if (!(condition)) 						\
262 		__wait_event_timeout(wq, condition, __ret);		\
263 	__ret;								\
264 })
265 
266 #define __wait_event_interruptible(wq, condition, ret)			\
267 do {									\
268 	DEFINE_WAIT(__wait);						\
269 									\
270 	for (;;) {							\
271 		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
272 		if (condition)						\
273 			break;						\
274 		if (!signal_pending(current)) {				\
275 			schedule();					\
276 			continue;					\
277 		}							\
278 		ret = -ERESTARTSYS;					\
279 		break;							\
280 	}								\
281 	finish_wait(&wq, &__wait);					\
282 } while (0)
283 
284 /**
285  * wait_event_interruptible - sleep until a condition gets true
286  * @wq: the waitqueue to wait on
287  * @condition: a C expression for the event to wait for
288  *
289  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
290  * @condition evaluates to true or a signal is received.
291  * The @condition is checked each time the waitqueue @wq is woken up.
292  *
293  * wake_up() has to be called after changing any variable that could
294  * change the result of the wait condition.
295  *
296  * The function will return -ERESTARTSYS if it was interrupted by a
297  * signal and 0 if @condition evaluated to true.
298  */
299 #define wait_event_interruptible(wq, condition)				\
300 ({									\
301 	int __ret = 0;							\
302 	if (!(condition))						\
303 		__wait_event_interruptible(wq, condition, __ret);	\
304 	__ret;								\
305 })
306 
307 #define __wait_event_interruptible_timeout(wq, condition, ret)		\
308 do {									\
309 	DEFINE_WAIT(__wait);						\
310 									\
311 	for (;;) {							\
312 		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
313 		if (condition)						\
314 			break;						\
315 		if (!signal_pending(current)) {				\
316 			ret = schedule_timeout(ret);			\
317 			if (!ret)					\
318 				break;					\
319 			continue;					\
320 		}							\
321 		ret = -ERESTARTSYS;					\
322 		break;							\
323 	}								\
324 	if (!ret && (condition))					\
325 		ret = 1;						\
326 	finish_wait(&wq, &__wait);					\
327 } while (0)
328 
329 /**
330  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
331  * @wq: the waitqueue to wait on
332  * @condition: a C expression for the event to wait for
333  * @timeout: timeout, in jiffies
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  * Returns:
343  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
344  * a signal, or the remaining jiffies (at least 1) if the @condition
345  * evaluated to %true before the @timeout elapsed.
346  */
347 #define wait_event_interruptible_timeout(wq, condition, timeout)	\
348 ({									\
349 	long __ret = timeout;						\
350 	if (!(condition))						\
351 		__wait_event_interruptible_timeout(wq, condition, __ret); \
352 	__ret;								\
353 })
354 
355 #define __wait_event_interruptible_exclusive(wq, condition, ret)	\
356 do {									\
357 	DEFINE_WAIT(__wait);						\
358 									\
359 	for (;;) {							\
360 		prepare_to_wait_exclusive(&wq, &__wait,			\
361 					TASK_INTERRUPTIBLE);		\
362 		if (condition) {					\
363 			finish_wait(&wq, &__wait);			\
364 			break;						\
365 		}							\
366 		if (!signal_pending(current)) {				\
367 			schedule();					\
368 			continue;					\
369 		}							\
370 		ret = -ERESTARTSYS;					\
371 		abort_exclusive_wait(&wq, &__wait, 			\
372 				TASK_INTERRUPTIBLE, NULL);		\
373 		break;							\
374 	}								\
375 } while (0)
376 
377 #define wait_event_interruptible_exclusive(wq, condition)		\
378 ({									\
379 	int __ret = 0;							\
380 	if (!(condition))						\
381 		__wait_event_interruptible_exclusive(wq, condition, __ret);\
382 	__ret;								\
383 })
384 
385 
386 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
387 ({									\
388 	int __ret = 0;							\
389 	DEFINE_WAIT(__wait);						\
390 	if (exclusive)							\
391 		__wait.flags |= WQ_FLAG_EXCLUSIVE;			\
392 	do {								\
393 		if (likely(list_empty(&__wait.task_list)))		\
394 			__add_wait_queue_tail(&(wq), &__wait);		\
395 		set_current_state(TASK_INTERRUPTIBLE);			\
396 		if (signal_pending(current)) {				\
397 			__ret = -ERESTARTSYS;				\
398 			break;						\
399 		}							\
400 		if (irq)						\
401 			spin_unlock_irq(&(wq).lock);			\
402 		else							\
403 			spin_unlock(&(wq).lock);			\
404 		schedule();						\
405 		if (irq)						\
406 			spin_lock_irq(&(wq).lock);			\
407 		else							\
408 			spin_lock(&(wq).lock);				\
409 	} while (!(condition));						\
410 	__remove_wait_queue(&(wq), &__wait);				\
411 	__set_current_state(TASK_RUNNING);				\
412 	__ret;								\
413 })
414 
415 
416 /**
417  * wait_event_interruptible_locked - sleep until a condition gets true
418  * @wq: the waitqueue to wait on
419  * @condition: a C expression for the event to wait for
420  *
421  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
422  * @condition evaluates to true or a signal is received.
423  * The @condition is checked each time the waitqueue @wq is woken up.
424  *
425  * It must be called with wq.lock being held.  This spinlock is
426  * unlocked while sleeping but @condition testing is done while lock
427  * is held and when this macro exits the lock is held.
428  *
429  * The lock is locked/unlocked using spin_lock()/spin_unlock()
430  * functions which must match the way they are locked/unlocked outside
431  * of this macro.
432  *
433  * wake_up_locked() has to be called after changing any variable that could
434  * change the result of the wait condition.
435  *
436  * The function will return -ERESTARTSYS if it was interrupted by a
437  * signal and 0 if @condition evaluated to true.
438  */
439 #define wait_event_interruptible_locked(wq, condition)			\
440 	((condition)							\
441 	 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
442 
443 /**
444  * wait_event_interruptible_locked_irq - sleep until a condition gets true
445  * @wq: the waitqueue to wait on
446  * @condition: a C expression for the event to wait for
447  *
448  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
449  * @condition evaluates to true or a signal is received.
450  * The @condition is checked each time the waitqueue @wq is woken up.
451  *
452  * It must be called with wq.lock being held.  This spinlock is
453  * unlocked while sleeping but @condition testing is done while lock
454  * is held and when this macro exits the lock is held.
455  *
456  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
457  * functions which must match the way they are locked/unlocked outside
458  * of this macro.
459  *
460  * wake_up_locked() has to be called after changing any variable that could
461  * change the result of the wait condition.
462  *
463  * The function will return -ERESTARTSYS if it was interrupted by a
464  * signal and 0 if @condition evaluated to true.
465  */
466 #define wait_event_interruptible_locked_irq(wq, condition)		\
467 	((condition)							\
468 	 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
469 
470 /**
471  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
472  * @wq: the waitqueue to wait on
473  * @condition: a C expression for the event to wait for
474  *
475  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
476  * @condition evaluates to true or a signal is received.
477  * The @condition is checked each time the waitqueue @wq is woken up.
478  *
479  * It must be called with wq.lock being held.  This spinlock is
480  * unlocked while sleeping but @condition testing is done while lock
481  * is held and when this macro exits the lock is held.
482  *
483  * The lock is locked/unlocked using spin_lock()/spin_unlock()
484  * functions which must match the way they are locked/unlocked outside
485  * of this macro.
486  *
487  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
488  * set thus when other process waits process on the list if this
489  * process is awaken further processes are not considered.
490  *
491  * wake_up_locked() has to be called after changing any variable that could
492  * change the result of the wait condition.
493  *
494  * The function will return -ERESTARTSYS if it was interrupted by a
495  * signal and 0 if @condition evaluated to true.
496  */
497 #define wait_event_interruptible_exclusive_locked(wq, condition)	\
498 	((condition)							\
499 	 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
500 
501 /**
502  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
503  * @wq: the waitqueue to wait on
504  * @condition: a C expression for the event to wait for
505  *
506  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
507  * @condition evaluates to true or a signal is received.
508  * The @condition is checked each time the waitqueue @wq is woken up.
509  *
510  * It must be called with wq.lock being held.  This spinlock is
511  * unlocked while sleeping but @condition testing is done while lock
512  * is held and when this macro exits the lock is held.
513  *
514  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
515  * functions which must match the way they are locked/unlocked outside
516  * of this macro.
517  *
518  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
519  * set thus when other process waits process on the list if this
520  * process is awaken further processes are not considered.
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_exclusive_locked_irq(wq, condition)	\
529 	((condition)							\
530 	 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
531 
532 
533 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,	\
534 						    lock, ret)		\
535 do {									\
536 	DEFINE_WAIT(__wait);						\
537 									\
538 	for (;;) {							\
539 		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
540 		if (condition)						\
541 			break;						\
542 		if (signal_pending(current)) {				\
543 			ret = -ERESTARTSYS;				\
544 			break;						\
545 		}							\
546 		spin_unlock_irq(&lock);					\
547 		ret = schedule_timeout(ret);				\
548 		spin_lock_irq(&lock);					\
549 		if (!ret)						\
550 			break;						\
551 	}								\
552 	finish_wait(&wq, &__wait);					\
553 } while (0)
554 
555 /**
556  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses.
557  *		The condition is checked under the lock. This is expected
558  *		to be called with the lock taken.
559  * @wq: the waitqueue to wait on
560  * @condition: a C expression for the event to wait for
561  * @lock: a locked spinlock_t, which will be released before schedule()
562  *	  and reacquired afterwards.
563  * @timeout: timeout, in jiffies
564  *
565  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
566  * @condition evaluates to true or signal is received. The @condition is
567  * checked each time the waitqueue @wq is woken up.
568  *
569  * wake_up() has to be called after changing any variable that could
570  * change the result of the wait condition.
571  *
572  * This is supposed to be called while holding the lock. The lock is
573  * dropped before going to sleep and is reacquired afterwards.
574  *
575  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
576  * was interrupted by a signal, and the remaining jiffies otherwise
577  * if the condition evaluated to true before the timeout elapsed.
578  */
579 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,	\
580 						  timeout)		\
581 ({									\
582 	int __ret = timeout;						\
583 									\
584 	if (!(condition))						\
585 		__wait_event_interruptible_lock_irq_timeout(		\
586 					wq, condition, lock, __ret);	\
587 	__ret;								\
588 })
589 
590 
591 #define __wait_event_killable(wq, condition, ret)			\
592 do {									\
593 	DEFINE_WAIT(__wait);						\
594 									\
595 	for (;;) {							\
596 		prepare_to_wait(&wq, &__wait, TASK_KILLABLE);		\
597 		if (condition)						\
598 			break;						\
599 		if (!fatal_signal_pending(current)) {			\
600 			schedule();					\
601 			continue;					\
602 		}							\
603 		ret = -ERESTARTSYS;					\
604 		break;							\
605 	}								\
606 	finish_wait(&wq, &__wait);					\
607 } while (0)
608 
609 /**
610  * wait_event_killable - sleep until a condition gets true
611  * @wq: the waitqueue to wait on
612  * @condition: a C expression for the event to wait for
613  *
614  * The process is put to sleep (TASK_KILLABLE) until the
615  * @condition evaluates to true or a signal is received.
616  * The @condition is checked each time the waitqueue @wq is woken up.
617  *
618  * wake_up() has to be called after changing any variable that could
619  * change the result of the wait condition.
620  *
621  * The function will return -ERESTARTSYS if it was interrupted by a
622  * signal and 0 if @condition evaluated to true.
623  */
624 #define wait_event_killable(wq, condition)				\
625 ({									\
626 	int __ret = 0;							\
627 	if (!(condition))						\
628 		__wait_event_killable(wq, condition, __ret);		\
629 	__ret;								\
630 })
631 
632 /*
633  * These are the old interfaces to sleep waiting for an event.
634  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
635  * We plan to remove these interfaces.
636  */
637 extern void sleep_on(wait_queue_head_t *q);
638 extern long sleep_on_timeout(wait_queue_head_t *q,
639 				      signed long timeout);
640 extern void interruptible_sleep_on(wait_queue_head_t *q);
641 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
642 					   signed long timeout);
643 
644 /*
645  * Waitqueues which are removed from the waitqueue_head at wakeup time
646  */
647 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
648 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
649 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
650 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
651 			unsigned int mode, void *key);
652 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
653 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
654 
655 #define DEFINE_WAIT_FUNC(name, function)				\
656 	wait_queue_t name = {						\
657 		.private	= current,				\
658 		.func		= function,				\
659 		.task_list	= LIST_HEAD_INIT((name).task_list),	\
660 	}
661 
662 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
663 
664 #define DEFINE_WAIT_BIT(name, word, bit)				\
665 	struct wait_bit_queue name = {					\
666 		.key = __WAIT_BIT_KEY_INITIALIZER(word, bit),		\
667 		.wait	= {						\
668 			.private	= current,			\
669 			.func		= wake_bit_function,		\
670 			.task_list	=				\
671 				LIST_HEAD_INIT((name).wait.task_list),	\
672 		},							\
673 	}
674 
675 #define init_wait(wait)							\
676 	do {								\
677 		(wait)->private = current;				\
678 		(wait)->func = autoremove_wake_function;		\
679 		INIT_LIST_HEAD(&(wait)->task_list);			\
680 		(wait)->flags = 0;					\
681 	} while (0)
682 
683 /**
684  * wait_on_bit - wait for a bit to be cleared
685  * @word: the word being waited on, a kernel virtual address
686  * @bit: the bit of the word being waited on
687  * @action: the function used to sleep, which may take special actions
688  * @mode: the task state to sleep in
689  *
690  * There is a standard hashed waitqueue table for generic use. This
691  * is the part of the hashtable's accessor API that waits on a bit.
692  * For instance, if one were to have waiters on a bitflag, one would
693  * call wait_on_bit() in threads waiting for the bit to clear.
694  * One uses wait_on_bit() where one is waiting for the bit to clear,
695  * but has no intention of setting it.
696  */
wait_on_bit(void * word,int bit,int (* action)(void *),unsigned mode)697 static inline int wait_on_bit(void *word, int bit,
698 				int (*action)(void *), unsigned mode)
699 {
700 	if (!test_bit(bit, word))
701 		return 0;
702 	return out_of_line_wait_on_bit(word, bit, action, mode);
703 }
704 
705 /**
706  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
707  * @word: the word being waited on, a kernel virtual address
708  * @bit: the bit of the word being waited on
709  * @action: the function used to sleep, which may take special actions
710  * @mode: the task state to sleep in
711  *
712  * There is a standard hashed waitqueue table for generic use. This
713  * is the part of the hashtable's accessor API that waits on a bit
714  * when one intends to set it, for instance, trying to lock bitflags.
715  * For instance, if one were to have waiters trying to set bitflag
716  * and waiting for it to clear before setting it, one would call
717  * wait_on_bit() in threads waiting to be able to set the bit.
718  * One uses wait_on_bit_lock() where one is waiting for the bit to
719  * clear with the intention of setting it, and when done, clearing it.
720  */
wait_on_bit_lock(void * word,int bit,int (* action)(void *),unsigned mode)721 static inline int wait_on_bit_lock(void *word, int bit,
722 				int (*action)(void *), unsigned mode)
723 {
724 	if (!test_and_set_bit(bit, word))
725 		return 0;
726 	return out_of_line_wait_on_bit_lock(word, bit, action, mode);
727 }
728 
729 #endif /* __KERNEL__ */
730 
731 #endif
732