[deliverable/linux.git] / include / linux / wait.h

#ifndef _LINUX_WAIT_H
#define _LINUX_WAIT_H

#define WNOHANG		0x00000001
#define WUNTRACED	0x00000002
#define WSTOPPED	WUNTRACED
#define WEXITED		0x00000004
#define WCONTINUED	0x00000008
#define WNOWAIT		0x01000000	/* Don't reap, just poll status.  */

#define __WNOTHREAD	0x20000000	/* Don't wait on children of other threads in this group */
#define __WALL		0x40000000	/* Wait on all children, regardless of type */
#define __WCLONE	0x80000000	/* Wait only on non-SIGCHLD children */

/* First argument to waitid: */
#define P_ALL		0
#define P_PID		1
#define P_PGID		2

#ifdef __KERNEL__

#include <linux/config.h>
#include <linux/list.h>
#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <asm/system.h>
#include <asm/current.h>

typedef struct __wait_queue wait_queue_t;
typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int sync, void *key);
int default_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);

struct __wait_queue {
	unsigned int flags;
#define WQ_FLAG_EXCLUSIVE	0x01
	void *private;
	wait_queue_func_t func;
	struct list_head task_list;
};

struct wait_bit_key {
	void *flags;
	int bit_nr;
};

struct wait_bit_queue {
	struct wait_bit_key key;
	wait_queue_t wait;
};

struct __wait_queue_head {
	spinlock_t lock;
	struct list_head task_list;
};
typedef struct __wait_queue_head wait_queue_head_t;

struct task_struct;

/*
 * Macros for declaration and initialisaton of the datatypes
 */

#define __WAITQUEUE_INITIALIZER(name, tsk) {				\
	.private	= tsk,						\
	.func		= default_wake_function,			\
	.task_list	= { NULL, NULL } }

#define DECLARE_WAITQUEUE(name, tsk)					\
	wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)

#define __WAIT_QUEUE_HEAD_INITIALIZER(name) {				\
	.lock		= SPIN_LOCK_UNLOCKED,				\
	.task_list	= { &(name).task_list, &(name).task_list } }

#define DECLARE_WAIT_QUEUE_HEAD(name) \
	wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)

#define __WAIT_BIT_KEY_INITIALIZER(word, bit)				\
	{ .flags = word, .bit_nr = bit, }

static inline void init_waitqueue_head(wait_queue_head_t *q)
{
	spin_lock_init(&q->lock);
	INIT_LIST_HEAD(&q->task_list);
}

static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
{
	q->flags = 0;
	q->private = p;
	q->func = default_wake_function;
}

static inline void init_waitqueue_func_entry(wait_queue_t *q,
					wait_queue_func_t func)
{
	q->flags = 0;
	q->private = NULL;
	q->func = func;
}

static inline int waitqueue_active(wait_queue_head_t *q)
{
	return !list_empty(&q->task_list);
}

/*
 * Used to distinguish between sync and async io wait context:
 * sync i/o typically specifies a NULL wait queue entry or a wait
 * queue entry bound to a task (current task) to wake up.
 * aio specifies a wait queue entry with an async notification
 * callback routine, not associated with any task.
 */
#define is_sync_wait(wait)	(!(wait) || ((wait)->private))

extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));

static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
{
	list_add(&new->task_list, &head->task_list);
}

/*
 * Used for wake-one threads:
 */
static inline void __add_wait_queue_tail(wait_queue_head_t *head,
						wait_queue_t *new)
{
	list_add_tail(&new->task_list, &head->task_list);
}

static inline void __remove_wait_queue(wait_queue_head_t *head,
							wait_queue_t *old)
{
	list_del(&old->task_list);
}

void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key));
extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
void FASTCALL(__wake_up_bit(wait_queue_head_t *, void *, int));
int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
void FASTCALL(wake_up_bit(void *, int));
int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned));
int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned));
wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int));

#define wake_up(x)			__wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL)
#define wake_up_nr(x, nr)		__wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL)
#define wake_up_all(x)			__wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL)
#define wake_up_interruptible(x)	__wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
#define wake_up_interruptible_nr(x, nr)	__wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
#define wake_up_interruptible_all(x)	__wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
#define	wake_up_locked(x)		__wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE)
#define wake_up_interruptible_sync(x)   __wake_up_sync((x),TASK_INTERRUPTIBLE, 1)

#define __wait_event(wq, condition) 					\
do {									\
	DEFINE_WAIT(__wait);						\
									\
	for (;;) {							\
		prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);	\
		if (condition)						\
			break;						\
		schedule();						\
	}								\
	finish_wait(&wq, &__wait);					\
} while (0)

/**
 * wait_event - sleep until a condition gets true
 * @wq: the waitqueue to wait on
 * @condition: a C expression for the event to wait for
 *
 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 * @condition evaluates to true. The @condition is checked each time
 * the waitqueue @wq is woken up.
 *
 * wake_up() has to be called after changing any variable that could
 * change the result of the wait condition.
 */
#define wait_event(wq, condition) 					\
do {									\
	if (condition)	 						\
		break;							\
	__wait_event(wq, condition);					\
} while (0)

#define __wait_event_timeout(wq, condition, ret)			\
do {									\
	DEFINE_WAIT(__wait);						\
									\
	for (;;) {							\
		prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);	\
		if (condition)						\
			break;						\
		ret = schedule_timeout(ret);				\
		if (!ret)						\
			break;						\
	}								\
	finish_wait(&wq, &__wait);					\
} while (0)

/**
 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 * @wq: the waitqueue to wait on
 * @condition: a C expression for the event to wait for
 * @timeout: timeout, in jiffies
 *
 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 * @condition evaluates to true. The @condition is checked each time
 * the waitqueue @wq is woken up.
 *
 * wake_up() has to be called after changing any variable that could
 * change the result of the wait condition.
 *
 * The function returns 0 if the @timeout elapsed, and the remaining
 * jiffies if the condition evaluated to true before the timeout elapsed.
 */
#define wait_event_timeout(wq, condition, timeout)			\
({									\
	long __ret = timeout;						\
	if (!(condition)) 						\
		__wait_event_timeout(wq, condition, __ret);		\
	__ret;								\
})

#define __wait_event_interruptible(wq, condition, ret)			\
do {									\
	DEFINE_WAIT(__wait);						\
									\
	for (;;) {							\
		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
		if (condition)						\
			break;						\
		if (!signal_pending(current)) {				\
			schedule();					\
			continue;					\
		}							\
		ret = -ERESTARTSYS;					\
		break;							\
	}								\
	finish_wait(&wq, &__wait);					\
} while (0)

/**
 * wait_event_interruptible - sleep until a condition gets true
 * @wq: the waitqueue to wait on
 * @condition: a C expression for the event to wait for
 *
 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 * @condition evaluates to true or a signal is received.
 * The @condition is checked each time the waitqueue @wq is woken up.
 *
 * wake_up() has to be called after changing any variable that could
 * change the result of the wait condition.
 *
 * The function will return -ERESTARTSYS if it was interrupted by a
 * signal and 0 if @condition evaluated to true.
 */
#define wait_event_interruptible(wq, condition)				\
({									\
	int __ret = 0;							\
	if (!(condition))						\
		__wait_event_interruptible(wq, condition, __ret);	\
	__ret;								\
})

#define __wait_event_interruptible_timeout(wq, condition, ret)		\
do {									\
	DEFINE_WAIT(__wait);						\
									\
	for (;;) {							\
		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
		if (condition)						\
			break;						\
		if (!signal_pending(current)) {				\
			ret = schedule_timeout(ret);			\
			if (!ret)					\
				break;					\
			continue;					\
		}							\
		ret = -ERESTARTSYS;					\
		break;							\
	}								\
	finish_wait(&wq, &__wait);					\
} while (0)

/**
 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 * @wq: the waitqueue to wait on
 * @condition: a C expression for the event to wait for
 * @timeout: timeout, in jiffies
 *
 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 * @condition evaluates to true or a signal is received.
 * The @condition is checked each time the waitqueue @wq is woken up.
 *
 * wake_up() has to be called after changing any variable that could
 * change the result of the wait condition.
 *
 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 * was interrupted by a signal, and the remaining jiffies otherwise
 * if the condition evaluated to true before the timeout elapsed.
 */
#define wait_event_interruptible_timeout(wq, condition, timeout)	\
({									\
	long __ret = timeout;						\
	if (!(condition))						\
		__wait_event_interruptible_timeout(wq, condition, __ret); \
	__ret;								\
})

#define __wait_event_interruptible_exclusive(wq, condition, ret)	\
do {									\
	DEFINE_WAIT(__wait);						\
									\
	for (;;) {							\
		prepare_to_wait_exclusive(&wq, &__wait,			\
					TASK_INTERRUPTIBLE);		\
		if (condition)						\
			break;						\
		if (!signal_pending(current)) {				\
			schedule();					\
			continue;					\
		}							\
		ret = -ERESTARTSYS;					\
		break;							\
	}								\
	finish_wait(&wq, &__wait);					\
} while (0)

#define wait_event_interruptible_exclusive(wq, condition)		\
({									\
	int __ret = 0;							\
	if (!(condition))						\
		__wait_event_interruptible_exclusive(wq, condition, __ret);\
	__ret;								\
})

/*
 * Must be called with the spinlock in the wait_queue_head_t held.
 */
static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
						   wait_queue_t * wait)
{
	wait->flags |= WQ_FLAG_EXCLUSIVE;
	__add_wait_queue_tail(q,  wait);
}

/*
 * Must be called with the spinlock in the wait_queue_head_t held.
 */
static inline void remove_wait_queue_locked(wait_queue_head_t *q,
					    wait_queue_t * wait)
{
	__remove_wait_queue(q,  wait);
}

/*
 * These are the old interfaces to sleep waiting for an event.
 * They are racy.  DO NOT use them, use the wait_event* interfaces above.  
 * We plan to remove these interfaces during 2.7.
 */
extern void FASTCALL(sleep_on(wait_queue_head_t *q));
extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
				      signed long timeout));
extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
						    signed long timeout));

/*
 * Waitqueues which are removed from the waitqueue_head at wakeup time
 */
void FASTCALL(prepare_to_wait(wait_queue_head_t *q,
				wait_queue_t *wait, int state));
void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q,
				wait_queue_t *wait, int state));
void FASTCALL(finish_wait(wait_queue_head_t *q, wait_queue_t *wait));
int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);

#define DEFINE_WAIT(name)						\
	wait_queue_t name = {						\
		.private	= current,				\
		.func		= autoremove_wake_function,		\
		.task_list	= LIST_HEAD_INIT((name).task_list),	\
	}

#define DEFINE_WAIT_BIT(name, word, bit)				\
	struct wait_bit_queue name = {					\
		.key = __WAIT_BIT_KEY_INITIALIZER(word, bit),		\
		.wait	= {						\
			.private	= current,			\
			.func		= wake_bit_function,		\
			.task_list	=				\
				LIST_HEAD_INIT((name).wait.task_list),	\
		},							\
	}

#define init_wait(wait)							\
	do {								\
		(wait)->private = current;				\
		(wait)->func = autoremove_wake_function;		\
		INIT_LIST_HEAD(&(wait)->task_list);			\
	} while (0)

/**
 * wait_on_bit - wait for a bit to be cleared
 * @word: the word being waited on, a kernel virtual address
 * @bit: the bit of the word being waited on
 * @action: the function used to sleep, which may take special actions
 * @mode: the task state to sleep in
 *
 * There is a standard hashed waitqueue table for generic use. This
 * is the part of the hashtable's accessor API that waits on a bit.
 * For instance, if one were to have waiters on a bitflag, one would
 * call wait_on_bit() in threads waiting for the bit to clear.
 * One uses wait_on_bit() where one is waiting for the bit to clear,
 * but has no intention of setting it.
 */
static inline int wait_on_bit(void *word, int bit,
				int (*action)(void *), unsigned mode)
{
	if (!test_bit(bit, word))
		return 0;
	return out_of_line_wait_on_bit(word, bit, action, mode);
}

/**
 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 * @word: the word being waited on, a kernel virtual address
 * @bit: the bit of the word being waited on
 * @action: the function used to sleep, which may take special actions
 * @mode: the task state to sleep in
 *
 * There is a standard hashed waitqueue table for generic use. This
 * is the part of the hashtable's accessor API that waits on a bit
 * when one intends to set it, for instance, trying to lock bitflags.
 * For instance, if one were to have waiters trying to set bitflag
 * and waiting for it to clear before setting it, one would call
 * wait_on_bit() in threads waiting to be able to set the bit.
 * One uses wait_on_bit_lock() where one is waiting for the bit to
 * clear with the intention of setting it, and when done, clearing it.
 */
static inline int wait_on_bit_lock(void *word, int bit,
				int (*action)(void *), unsigned mode)
{
	if (!test_and_set_bit(bit, word))
		return 0;
	return out_of_line_wait_on_bit_lock(word, bit, action, mode);
}
	
#endif /* __KERNEL__ */

#endif
Commit	Line	Data
1da177e4 LT	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/config.h>
	23	#include <linux/list.h>
	24	#include <linux/stddef.h>
	25	#include <linux/spinlock.h>
	26	#include <asm/system.h>
	27	#include <asm/current.h>
	28
	29	typedef struct __wait_queue wait_queue_t;
	30	typedef int (wait_queue_func_t)(wait_queue_t wait, unsigned mode, int sync, void *key);
	31	int default_wake_function(wait_queue_t wait, unsigned mode, int sync, void key);
	32
	33	struct __wait_queue {
	34	unsigned int flags;
	35	#define WQ_FLAG_EXCLUSIVE 0x01
c43dc2fd	36	void *private;
1da177e4 LT	37	wait_queue_func_t func;
	38	struct list_head task_list;
	39	};
	40
	41	struct wait_bit_key {
	42	void *flags;
	43	int bit_nr;
	44	};
	45
	46	struct wait_bit_queue {
	47	struct wait_bit_key key;
	48	wait_queue_t wait;
	49	};
	50
	51	struct __wait_queue_head {
	52	spinlock_t lock;
	53	struct list_head task_list;
	54	};
	55	typedef struct __wait_queue_head wait_queue_head_t;
	56
8c65b4a6	57	struct task_struct;
1da177e4 LT	58
	59	/*
	60	* Macros for declaration and initialisaton of the datatypes
	61	*/
	62
	63	#define __WAITQUEUE_INITIALIZER(name, tsk) { \
c43dc2fd	64	.private = tsk, \
1da177e4 LT	65	.func = default_wake_function, \
	66	.task_list = { NULL, NULL } }
	67
	68	#define DECLARE_WAITQUEUE(name, tsk) \
	69	wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
	70
	71	#define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
	72	.lock = SPIN_LOCK_UNLOCKED, \
	73	.task_list = { &(name).task_list, &(name).task_list } }
	74
	75	#define DECLARE_WAIT_QUEUE_HEAD(name) \
	76	wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
	77
	78	#define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
	79	{ .flags = word, .bit_nr = bit, }
	80
	81	static inline void init_waitqueue_head(wait_queue_head_t *q)
	82	{
	83	spin_lock_init(&q->lock);
	84	INIT_LIST_HEAD(&q->task_list);
	85	}
	86
	87	static inline void init_waitqueue_entry(wait_queue_t q, struct task_struct p)
	88	{
	89	q->flags = 0;
c43dc2fd	90	q->private = p;
1da177e4 LT	91	q->func = default_wake_function;
	92	}
	93
	94	static inline void init_waitqueue_func_entry(wait_queue_t *q,
	95	wait_queue_func_t func)
	96	{
	97	q->flags = 0;
c43dc2fd	98	q->private = NULL;
1da177e4 LT	99	q->func = func;
	100	}
	101
	102	static inline int waitqueue_active(wait_queue_head_t *q)
	103	{
	104	return !list_empty(&q->task_list);
	105	}
	106
	107	/*
	108	* Used to distinguish between sync and async io wait context:
	109	* sync i/o typically specifies a NULL wait queue entry or a wait
	110	* queue entry bound to a task (current task) to wake up.
	111	* aio specifies a wait queue entry with an async notification
	112	* callback routine, not associated with any task.
	113	*/
c43dc2fd	114	#define is_sync_wait(wait) (!(wait) \|\| ((wait)->private))
1da177e4 LT	115
	116	extern void FASTCALL(add_wait_queue(wait_queue_head_t q, wait_queue_t wait));
	117	extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t q, wait_queue_t wait));
	118	extern void FASTCALL(remove_wait_queue(wait_queue_head_t q, wait_queue_t wait));
	119
	120	static inline void __add_wait_queue(wait_queue_head_t head, wait_queue_t new)
	121	{
	122	list_add(&new->task_list, &head->task_list);
	123	}
	124
	125	/*
	126	* Used for wake-one threads:
	127	*/
	128	static inline void __add_wait_queue_tail(wait_queue_head_t *head,
	129	wait_queue_t *new)
	130	{
	131	list_add_tail(&new->task_list, &head->task_list);
	132	}
	133
	134	static inline void __remove_wait_queue(wait_queue_head_t *head,
	135	wait_queue_t *old)
	136	{
	137	list_del(&old->task_list);
	138	}
	139
	140	void FASTCALL(__wake_up(wait_queue_head_t q, unsigned int mode, int nr, void key));
	141	extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
	142	extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
	143	void FASTCALL(__wake_up_bit(wait_queue_head_t , void , int));
	144	int FASTCALL(__wait_on_bit(wait_queue_head_t , struct wait_bit_queue , int ()(void ), unsigned));
	145	int FASTCALL(__wait_on_bit_lock(wait_queue_head_t , struct wait_bit_queue , int ()(void ), unsigned));
	146	void FASTCALL(wake_up_bit(void *, int));
	147	int FASTCALL(out_of_line_wait_on_bit(void , int, int ()(void *), unsigned));
	148	int FASTCALL(out_of_line_wait_on_bit_lock(void , int, int ()(void *), unsigned));
	149	wait_queue_head_t FASTCALL(bit_waitqueue(void , int));
	150
	151	#define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE \| TASK_INTERRUPTIBLE, 1, NULL)
	152	#define wake_up_nr(x, nr) __wake_up(x, TASK_UNINTERRUPTIBLE \| TASK_INTERRUPTIBLE, nr, NULL)
	153	#define wake_up_all(x) __wake_up(x, TASK_UNINTERRUPTIBLE \| TASK_INTERRUPTIBLE, 0, NULL)
	154	#define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
	155	#define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
	156	#define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
	157	#define wake_up_locked(x) __wake_up_locked((x), TASK_UNINTERRUPTIBLE \| TASK_INTERRUPTIBLE)
	158	#define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
	159
	160	#define __wait_event(wq, condition) \
	161	do { \
	162	DEFINE_WAIT(__wait); \
	163	\
	164	for (;;) { \
	165	prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
	166	if (condition) \
	167	break; \
	168	schedule(); \
	169	} \
	170	finish_wait(&wq, &__wait); \
	171	} while (0)
	172
	173	/**
	174	* wait_event - sleep until a condition gets true
	175	* @wq: the waitqueue to wait on
	176	* @condition: a C expression for the event to wait for
	177	*
	178	* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
179	* @condition evaluates to true. The @condition is checked each time
180	* the waitqueue @wq is woken up.
181	*
182	* wake_up() has to be called after changing any variable that could
183	* change the result of the wait condition.
184	*/
185	#define wait_event(wq, condition) \
186	do { \
187	if (condition) \
188	break; \
189	__wait_event(wq, condition); \
190	} while (0)
191
192	#define __wait_event_timeout(wq, condition, ret) \
193	do { \
194	DEFINE_WAIT(__wait); \
195	\
196	for (;;) { \
197	prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
198	if (condition) \
199	break; \
200	ret = schedule_timeout(ret); \
201	if (!ret) \
202	break; \
203	} \
204	finish_wait(&wq, &__wait); \
205	} while (0)
206
207	/**
208	* wait_event_timeout - sleep until a condition gets true or a timeout elapses
209	* @wq: the waitqueue to wait on
210	* @condition: a C expression for the event to wait for
211	* @timeout: timeout, in jiffies
212	*
213	* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
214	* @condition evaluates to true. The @condition is checked each time
215	* the waitqueue @wq is woken up.
216	*
217	* wake_up() has to be called after changing any variable that could
218	* change the result of the wait condition.
219	*
220	* The function returns 0 if the @timeout elapsed, and the remaining
221	* jiffies if the condition evaluated to true before the timeout elapsed.
222	*/
223	#define wait_event_timeout(wq, condition, timeout) \
224	({ \
225	long __ret = timeout; \
226	if (!(condition)) \
227	__wait_event_timeout(wq, condition, __ret); \
228	__ret; \
229	})
230
231	#define __wait_event_interruptible(wq, condition, ret) \
232	do { \
233	DEFINE_WAIT(__wait); \
234	\
235	for (;;) { \
236	prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
237	if (condition) \
238	break; \
239	if (!signal_pending(current)) { \
240	schedule(); \
241	continue; \
242	} \
243	ret = -ERESTARTSYS; \
244	break; \
245	} \
246	finish_wait(&wq, &__wait); \
247	} while (0)
248
249	/**
250	* wait_event_interruptible - sleep until a condition gets true
251	* @wq: the waitqueue to wait on
252	* @condition: a C expression for the event to wait for
253	*
254	* The process is put to sleep (TASK_INTERRUPTIBLE) until the
255	* @condition evaluates to true or a signal is received.
256	* The @condition is checked each time the waitqueue @wq is woken up.
257	*
258	* wake_up() has to be called after changing any variable that could
259	* change the result of the wait condition.
260	*
261	* The function will return -ERESTARTSYS if it was interrupted by a
262	* signal and 0 if @condition evaluated to true.
263	*/
264	#define wait_event_interruptible(wq, condition) \
265	({ \
266	int __ret = 0; \
267	if (!(condition)) \
268	__wait_event_interruptible(wq, condition, __ret); \
269	__ret; \
270	})
271
272	#define __wait_event_interruptible_timeout(wq, condition, ret) \
273	do { \
274	DEFINE_WAIT(__wait); \
275	\
276	for (;;) { \
277	prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
278	if (condition) \
279	break; \
280	if (!signal_pending(current)) { \
281	ret = schedule_timeout(ret); \
282	if (!ret) \
283	break; \
284	continue; \
285	} \
286	ret = -ERESTARTSYS; \
287	break; \
288	} \
289	finish_wait(&wq, &__wait); \
290	} while (0)
291
292	/**
293	* wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
294	* @wq: the waitqueue to wait on
295	* @condition: a C expression for the event to wait for
296	* @timeout: timeout, in jiffies
297	*
298	* The process is put to sleep (TASK_INTERRUPTIBLE) until the
299	* @condition evaluates to true or a signal is received.
300	* The @condition is checked each time the waitqueue @wq is woken up.
301	*
302	* wake_up() has to be called after changing any variable that could
303	* change the result of the wait condition.
304	*
305	* The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
306	* was interrupted by a signal, and the remaining jiffies otherwise
307	* if the condition evaluated to true before the timeout elapsed.
308	*/
309	#define wait_event_interruptible_timeout(wq, condition, timeout) \
310	({ \
311	long __ret = timeout; \
312	if (!(condition)) \
313	__wait_event_interruptible_timeout(wq, condition, __ret); \
314	__ret; \
315	})
316
317	#define __wait_event_interruptible_exclusive(wq, condition, ret) \
318	do { \
319	DEFINE_WAIT(__wait); \
320	\
321	for (;;) { \
322	prepare_to_wait_exclusive(&wq, &__wait, \
323	TASK_INTERRUPTIBLE); \
324	if (condition) \
325	break; \
326	if (!signal_pending(current)) { \
327	schedule(); \
328	continue; \
329	} \
330	ret = -ERESTARTSYS; \
331	break; \
332	} \
333	finish_wait(&wq, &__wait); \
334	} while (0)
335
336	#define wait_event_interruptible_exclusive(wq, condition) \
337	({ \
338	int __ret = 0; \
339	if (!(condition)) \
340	__wait_event_interruptible_exclusive(wq, condition, __ret);\
341	__ret; \
342	})
343
344	/*
345	* Must be called with the spinlock in the wait_queue_head_t held.
346	*/
347	static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
348	wait_queue_t * wait)
349	{
350	wait->flags \|= WQ_FLAG_EXCLUSIVE;
351	__add_wait_queue_tail(q, wait);
352	}
353
354	/*
355	* Must be called with the spinlock in the wait_queue_head_t held.
356	*/
357	static inline void remove_wait_queue_locked(wait_queue_head_t *q,
358	wait_queue_t * wait)
359	{
360	__remove_wait_queue(q, wait);
361	}
362
363	/*
364	* These are the old interfaces to sleep waiting for an event.
365	* They are racy. DO NOT use them, use the wait_event* interfaces above.
366	* We plan to remove these interfaces during 2.7.
367	*/
368	extern void FASTCALL(sleep_on(wait_queue_head_t *q));
369	extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
370	signed long timeout));
371	extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
372	extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
373	signed long timeout));
374
375	/*
376	* Waitqueues which are removed from the waitqueue_head at wakeup time
377	*/
378	void FASTCALL(prepare_to_wait(wait_queue_head_t *q,
379	wait_queue_t *wait, int state));
380	void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q,
381	wait_queue_t *wait, int state));
382	void FASTCALL(finish_wait(wait_queue_head_t q, wait_queue_t wait));
383	int autoremove_wake_function(wait_queue_t wait, unsigned mode, int sync, void key);
384	int wake_bit_function(wait_queue_t wait, unsigned mode, int sync, void key);
385
386	#define DEFINE_WAIT(name) \
387	wait_queue_t name = { \
c43dc2fd	388	.private = current, \
1da177e4	389	.func = autoremove_wake_function, \
7e43c84e	390	.task_list = LIST_HEAD_INIT((name).task_list), \
1da177e4 LT	391	}
	392
	393	#define DEFINE_WAIT_BIT(name, word, bit) \
	394	struct wait_bit_queue name = { \
	395	.key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
	396	.wait = { \
c43dc2fd	397	.private = current, \
1da177e4 LT	398	.func = wake_bit_function, \
	399	.task_list = \
	400	LIST_HEAD_INIT((name).wait.task_list), \
	401	}, \
	402	}
	403
	404	#define init_wait(wait) \
	405	do { \
c43dc2fd	406	(wait)->private = current; \
1da177e4 LT	407	(wait)->func = autoremove_wake_function; \
	408	INIT_LIST_HEAD(&(wait)->task_list); \
	409	} while (0)
	410
	411	/**
	412	* wait_on_bit - wait for a bit to be cleared
	413	* @word: the word being waited on, a kernel virtual address
	414	* @bit: the bit of the word being waited on
	415	* @action: the function used to sleep, which may take special actions
	416	* @mode: the task state to sleep in
	417	*
	418	* There is a standard hashed waitqueue table for generic use. This
	419	* is the part of the hashtable's accessor API that waits on a bit.
	420	* For instance, if one were to have waiters on a bitflag, one would
	421	* call wait_on_bit() in threads waiting for the bit to clear.
	422	* One uses wait_on_bit() where one is waiting for the bit to clear,
	423	* but has no intention of setting it.
	424	*/
	425	static inline int wait_on_bit(void *word, int bit,
	426	int (action)(void ), unsigned mode)
	427	{
	428	if (!test_bit(bit, word))
	429	return 0;
	430	return out_of_line_wait_on_bit(word, bit, action, mode);
	431	}
	432
	433	/**
	434	* wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
	435	* @word: the word being waited on, a kernel virtual address
	436	* @bit: the bit of the word being waited on
	437	* @action: the function used to sleep, which may take special actions
	438	* @mode: the task state to sleep in
	439	*
	440	* There is a standard hashed waitqueue table for generic use. This
	441	* is the part of the hashtable's accessor API that waits on a bit
	442	* when one intends to set it, for instance, trying to lock bitflags.
	443	* For instance, if one were to have waiters trying to set bitflag
	444	* and waiting for it to clear before setting it, one would call
	445	* wait_on_bit() in threads waiting to be able to set the bit.
	446	* One uses wait_on_bit_lock() where one is waiting for the bit to
	447	* clear with the intention of setting it, and when done, clearing it.
	448	*/
	449	static inline int wait_on_bit_lock(void *word, int bit,
	450	int (action)(void ), unsigned mode)
	451	{
	452	if (!test_and_set_bit(bit, word))
	453	return 0;
	454	return out_of_line_wait_on_bit_lock(word, bit, action, mode);
	455	}
	456
	457	#endif /* __KERNEL__ */
	458
	459	#endif