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