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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/system.h>
26 #include <asm/current.h>
27 
28 typedef struct __wait_queue wait_queue_t;
29 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int sync, void *key);
30 int default_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
31 
32 struct __wait_queue {
33 	unsigned int flags;
34 #define WQ_FLAG_EXCLUSIVE	0x01
35 	void *private;
36 	wait_queue_func_t func;
37 	struct list_head task_list;
38 };
39 
40 struct wait_bit_key {
41 	void *flags;
42 	int bit_nr;
43 };
44 
45 struct wait_bit_queue {
46 	struct wait_bit_key key;
47 	wait_queue_t wait;
48 };
49 
50 struct __wait_queue_head {
51 	spinlock_t lock;
52 	struct list_head task_list;
53 };
54 typedef struct __wait_queue_head wait_queue_head_t;
55 
56 struct task_struct;
57 
58 /*
59  * Macros for declaration and initialisaton of the datatypes
60  */
61 
62 #define __WAITQUEUE_INITIALIZER(name, tsk) {				\
63 	.private	= tsk,						\
64 	.func		= default_wake_function,			\
65 	.task_list	= { NULL, NULL } }
66 
67 #define DECLARE_WAITQUEUE(name, tsk)					\
68 	wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
69 
70 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {				\
71 	.lock		= __SPIN_LOCK_UNLOCKED(name.lock),		\
72 	.task_list	= { &(name).task_list, &(name).task_list } }
73 
74 #define DECLARE_WAIT_QUEUE_HEAD(name) \
75 	wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
76 
77 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)				\
78 	{ .flags = word, .bit_nr = bit, }
79 
80 extern void init_waitqueue_head(wait_queue_head_t *q);
81 
82 #ifdef CONFIG_LOCKDEP
83 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
84 	({ init_waitqueue_head(&name); name; })
85 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
86 	wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
87 #else
88 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
89 #endif
90 
init_waitqueue_entry(wait_queue_t * q,struct task_struct * p)91 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
92 {
93 	q->flags = 0;
94 	q->private = p;
95 	q->func = default_wake_function;
96 }
97 
init_waitqueue_func_entry(wait_queue_t * q,wait_queue_func_t func)98 static inline void init_waitqueue_func_entry(wait_queue_t *q,
99 					wait_queue_func_t func)
100 {
101 	q->flags = 0;
102 	q->private = NULL;
103 	q->func = func;
104 }
105 
waitqueue_active(wait_queue_head_t * q)106 static inline int waitqueue_active(wait_queue_head_t *q)
107 {
108 	return !list_empty(&q->task_list);
109 }
110 
111 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
112 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
113 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
114 
__add_wait_queue(wait_queue_head_t * head,wait_queue_t * new)115 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
116 {
117 	list_add(&new->task_list, &head->task_list);
118 }
119 
120 /*
121  * Used for wake-one threads:
122  */
__add_wait_queue_tail(wait_queue_head_t * head,wait_queue_t * new)123 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
124 						wait_queue_t *new)
125 {
126 	list_add_tail(&new->task_list, &head->task_list);
127 }
128 
__remove_wait_queue(wait_queue_head_t * head,wait_queue_t * old)129 static inline void __remove_wait_queue(wait_queue_head_t *head,
130 							wait_queue_t *old)
131 {
132 	list_del(&old->task_list);
133 }
134 
135 void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
136 			int nr_exclusive, int sync, void *key);
137 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
138 extern void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
139 extern void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
140 void __wake_up_bit(wait_queue_head_t *, void *, int);
141 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
142 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
143 void wake_up_bit(void *, int);
144 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
145 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
146 wait_queue_head_t *bit_waitqueue(void *, int);
147 
148 #define wake_up(x)			__wake_up(x, TASK_NORMAL, 1, NULL)
149 #define wake_up_nr(x, nr)		__wake_up(x, TASK_NORMAL, nr, NULL)
150 #define wake_up_all(x)			__wake_up(x, TASK_NORMAL, 0, NULL)
151 #define wake_up_locked(x)		__wake_up_locked((x), TASK_NORMAL)
152 
153 #define wake_up_interruptible(x)	__wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
154 #define wake_up_interruptible_nr(x, nr)	__wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
155 #define wake_up_interruptible_all(x)	__wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
156 #define wake_up_interruptible_sync(x)	__wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
157 
158 #ifdef CONFIG_DEBUG_LOCK_ALLOC
159 /*
160  * macro to avoid include hell
161  */
162 #define wake_up_nested(x, s)						\
163 do {									\
164 	unsigned long flags;						\
165 									\
166 	spin_lock_irqsave_nested(&(x)->lock, flags, (s));		\
167 	wake_up_locked(x); 						\
168 	spin_unlock_irqrestore(&(x)->lock, flags);			\
169 } while (0)
170 #else
171 #define wake_up_nested(x, s)		wake_up(x)
172 #endif
173 
174 #define __wait_event(wq, condition) 					\
175 do {									\
176 	DEFINE_WAIT(__wait);						\
177 									\
178 	for (;;) {							\
179 		prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);	\
180 		if (condition)						\
181 			break;						\
182 		schedule();						\
183 	}								\
184 	finish_wait(&wq, &__wait);					\
185 } while (0)
186 
187 /**
188  * wait_event - sleep until a condition gets true
189  * @wq: the waitqueue to wait on
190  * @condition: a C expression for the event to wait for
191  *
192  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
193  * @condition evaluates to true. The @condition is checked each time
194  * the waitqueue @wq is woken up.
195  *
196  * wake_up() has to be called after changing any variable that could
197  * change the result of the wait condition.
198  */
199 #define wait_event(wq, condition) 					\
200 do {									\
201 	if (condition)	 						\
202 		break;							\
203 	__wait_event(wq, condition);					\
204 } while (0)
205 
206 #define __wait_event_timeout(wq, condition, ret)			\
207 do {									\
208 	DEFINE_WAIT(__wait);						\
209 									\
210 	for (;;) {							\
211 		prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);	\
212 		if (condition)						\
213 			break;						\
214 		ret = schedule_timeout(ret);				\
215 		if (!ret)						\
216 			break;						\
217 	}								\
218 	finish_wait(&wq, &__wait);					\
219 } while (0)
220 
221 /**
222  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
223  * @wq: the waitqueue to wait on
224  * @condition: a C expression for the event to wait for
225  * @timeout: timeout, in jiffies
226  *
227  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
228  * @condition evaluates to true. The @condition is checked each time
229  * the waitqueue @wq is woken up.
230  *
231  * wake_up() has to be called after changing any variable that could
232  * change the result of the wait condition.
233  *
234  * The function returns 0 if the @timeout elapsed, and the remaining
235  * jiffies if the condition evaluated to true before the timeout elapsed.
236  */
237 #define wait_event_timeout(wq, condition, timeout)			\
238 ({									\
239 	long __ret = timeout;						\
240 	if (!(condition)) 						\
241 		__wait_event_timeout(wq, condition, __ret);		\
242 	__ret;								\
243 })
244 
245 #define __wait_event_interruptible(wq, condition, ret)			\
246 do {									\
247 	DEFINE_WAIT(__wait);						\
248 									\
249 	for (;;) {							\
250 		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
251 		if (condition)						\
252 			break;						\
253 		if (!signal_pending(current)) {				\
254 			schedule();					\
255 			continue;					\
256 		}							\
257 		ret = -ERESTARTSYS;					\
258 		break;							\
259 	}								\
260 	finish_wait(&wq, &__wait);					\
261 } while (0)
262 
263 /**
264  * wait_event_interruptible - sleep until a condition gets true
265  * @wq: the waitqueue to wait on
266  * @condition: a C expression for the event to wait for
267  *
268  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
269  * @condition evaluates to true or a signal is received.
270  * The @condition is checked each time the waitqueue @wq is woken up.
271  *
272  * wake_up() has to be called after changing any variable that could
273  * change the result of the wait condition.
274  *
275  * The function will return -ERESTARTSYS if it was interrupted by a
276  * signal and 0 if @condition evaluated to true.
277  */
278 #define wait_event_interruptible(wq, condition)				\
279 ({									\
280 	int __ret = 0;							\
281 	if (!(condition))						\
282 		__wait_event_interruptible(wq, condition, __ret);	\
283 	__ret;								\
284 })
285 
286 #define __wait_event_interruptible_timeout(wq, condition, ret)		\
287 do {									\
288 	DEFINE_WAIT(__wait);						\
289 									\
290 	for (;;) {							\
291 		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
292 		if (condition)						\
293 			break;						\
294 		if (!signal_pending(current)) {				\
295 			ret = schedule_timeout(ret);			\
296 			if (!ret)					\
297 				break;					\
298 			continue;					\
299 		}							\
300 		ret = -ERESTARTSYS;					\
301 		break;							\
302 	}								\
303 	finish_wait(&wq, &__wait);					\
304 } while (0)
305 
306 /**
307  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
308  * @wq: the waitqueue to wait on
309  * @condition: a C expression for the event to wait for
310  * @timeout: timeout, in jiffies
311  *
312  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
313  * @condition evaluates to true or a signal is received.
314  * The @condition is checked each time 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  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
320  * was interrupted by a signal, and the remaining jiffies otherwise
321  * if the condition evaluated to true before the timeout elapsed.
322  */
323 #define wait_event_interruptible_timeout(wq, condition, timeout)	\
324 ({									\
325 	long __ret = timeout;						\
326 	if (!(condition))						\
327 		__wait_event_interruptible_timeout(wq, condition, __ret); \
328 	__ret;								\
329 })
330 
331 #define __wait_event_interruptible_exclusive(wq, condition, ret)	\
332 do {									\
333 	DEFINE_WAIT(__wait);						\
334 									\
335 	for (;;) {							\
336 		prepare_to_wait_exclusive(&wq, &__wait,			\
337 					TASK_INTERRUPTIBLE);		\
338 		if (condition) {					\
339 			finish_wait(&wq, &__wait);			\
340 			break;						\
341 		}							\
342 		if (!signal_pending(current)) {				\
343 			schedule();					\
344 			continue;					\
345 		}							\
346 		ret = -ERESTARTSYS;					\
347 		abort_exclusive_wait(&wq, &__wait, 			\
348 				TASK_INTERRUPTIBLE, NULL);		\
349 		break;							\
350 	}								\
351 } while (0)
352 
353 #define wait_event_interruptible_exclusive(wq, condition)		\
354 ({									\
355 	int __ret = 0;							\
356 	if (!(condition))						\
357 		__wait_event_interruptible_exclusive(wq, condition, __ret);\
358 	__ret;								\
359 })
360 
361 #define __wait_event_killable(wq, condition, ret)			\
362 do {									\
363 	DEFINE_WAIT(__wait);						\
364 									\
365 	for (;;) {							\
366 		prepare_to_wait(&wq, &__wait, TASK_KILLABLE);		\
367 		if (condition)						\
368 			break;						\
369 		if (!fatal_signal_pending(current)) {			\
370 			schedule();					\
371 			continue;					\
372 		}							\
373 		ret = -ERESTARTSYS;					\
374 		break;							\
375 	}								\
376 	finish_wait(&wq, &__wait);					\
377 } while (0)
378 
379 /**
380  * wait_event_killable - sleep until a condition gets true
381  * @wq: the waitqueue to wait on
382  * @condition: a C expression for the event to wait for
383  *
384  * The process is put to sleep (TASK_KILLABLE) until the
385  * @condition evaluates to true or a signal is received.
386  * The @condition is checked each time the waitqueue @wq is woken up.
387  *
388  * wake_up() has to be called after changing any variable that could
389  * change the result of the wait condition.
390  *
391  * The function will return -ERESTARTSYS if it was interrupted by a
392  * signal and 0 if @condition evaluated to true.
393  */
394 #define wait_event_killable(wq, condition)				\
395 ({									\
396 	int __ret = 0;							\
397 	if (!(condition))						\
398 		__wait_event_killable(wq, condition, __ret);		\
399 	__ret;								\
400 })
401 
402 /*
403  * Must be called with the spinlock in the wait_queue_head_t held.
404  */
add_wait_queue_exclusive_locked(wait_queue_head_t * q,wait_queue_t * wait)405 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
406 						   wait_queue_t * wait)
407 {
408 	wait->flags |= WQ_FLAG_EXCLUSIVE;
409 	__add_wait_queue_tail(q,  wait);
410 }
411 
412 /*
413  * Must be called with the spinlock in the wait_queue_head_t held.
414  */
remove_wait_queue_locked(wait_queue_head_t * q,wait_queue_t * wait)415 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
416 					    wait_queue_t * wait)
417 {
418 	__remove_wait_queue(q,  wait);
419 }
420 
421 /*
422  * These are the old interfaces to sleep waiting for an event.
423  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
424  * We plan to remove these interfaces.
425  */
426 extern void sleep_on(wait_queue_head_t *q);
427 extern long sleep_on_timeout(wait_queue_head_t *q,
428 				      signed long timeout);
429 extern void interruptible_sleep_on(wait_queue_head_t *q);
430 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
431 					   signed long timeout);
432 
433 /*
434  * Waitqueues which are removed from the waitqueue_head at wakeup time
435  */
436 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
437 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
438 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
439 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
440 			unsigned int mode, void *key);
441 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
442 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
443 
444 #define DEFINE_WAIT(name)						\
445 	wait_queue_t name = {						\
446 		.private	= current,				\
447 		.func		= autoremove_wake_function,		\
448 		.task_list	= LIST_HEAD_INIT((name).task_list),	\
449 	}
450 
451 #define DEFINE_WAIT_BIT(name, word, bit)				\
452 	struct wait_bit_queue name = {					\
453 		.key = __WAIT_BIT_KEY_INITIALIZER(word, bit),		\
454 		.wait	= {						\
455 			.private	= current,			\
456 			.func		= wake_bit_function,		\
457 			.task_list	=				\
458 				LIST_HEAD_INIT((name).wait.task_list),	\
459 		},							\
460 	}
461 
462 #define init_wait(wait)							\
463 	do {								\
464 		(wait)->private = current;				\
465 		(wait)->func = autoremove_wake_function;		\
466 		INIT_LIST_HEAD(&(wait)->task_list);			\
467 	} while (0)
468 
469 /**
470  * wait_on_bit - wait for a bit to be cleared
471  * @word: the word being waited on, a kernel virtual address
472  * @bit: the bit of the word being waited on
473  * @action: the function used to sleep, which may take special actions
474  * @mode: the task state to sleep in
475  *
476  * There is a standard hashed waitqueue table for generic use. This
477  * is the part of the hashtable's accessor API that waits on a bit.
478  * For instance, if one were to have waiters on a bitflag, one would
479  * call wait_on_bit() in threads waiting for the bit to clear.
480  * One uses wait_on_bit() where one is waiting for the bit to clear,
481  * but has no intention of setting it.
482  */
wait_on_bit(void * word,int bit,int (* action)(void *),unsigned mode)483 static inline int wait_on_bit(void *word, int bit,
484 				int (*action)(void *), unsigned mode)
485 {
486 	if (!test_bit(bit, word))
487 		return 0;
488 	return out_of_line_wait_on_bit(word, bit, action, mode);
489 }
490 
491 /**
492  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
493  * @word: the word being waited on, a kernel virtual address
494  * @bit: the bit of the word being waited on
495  * @action: the function used to sleep, which may take special actions
496  * @mode: the task state to sleep in
497  *
498  * There is a standard hashed waitqueue table for generic use. This
499  * is the part of the hashtable's accessor API that waits on a bit
500  * when one intends to set it, for instance, trying to lock bitflags.
501  * For instance, if one were to have waiters trying to set bitflag
502  * and waiting for it to clear before setting it, one would call
503  * wait_on_bit() in threads waiting to be able to set the bit.
504  * One uses wait_on_bit_lock() where one is waiting for the bit to
505  * clear with the intention of setting it, and when done, clearing it.
506  */
wait_on_bit_lock(void * word,int bit,int (* action)(void *),unsigned mode)507 static inline int wait_on_bit_lock(void *word, int bit,
508 				int (*action)(void *), unsigned mode)
509 {
510 	if (!test_and_set_bit(bit, word))
511 		return 0;
512 	return out_of_line_wait_on_bit_lock(word, bit, action, mode);
513 }
514 
515 #endif /* __KERNEL__ */
516 
517 #endif
518