#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(name.lock),              \
        .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, }

extern void init_waitqueue_head(wait_queue_head_t *q);

#ifdef CONFIG_LOCKDEP
# define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
        ({ init_waitqueue_head(&name); name; })
# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
        wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
#else
# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
#endif

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

#define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
#define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
#define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
#define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL)

#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_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)

#ifdef CONFIG_DEBUG_LOCK_ALLOC
/*
 * macro to avoid include hell
 */
#define wake_up_nested(x, s)                                            \
do {                                                                    \
        unsigned long flags;                                            \
                                                                        \
        spin_lock_irqsave_nested(&(x)->lock, flags, (s));               \
        wake_up_locked(x);                                              \
        spin_unlock_irqrestore(&(x)->lock, flags);                      \
} while (0)
#else
#define wake_up_nested(x, s)            wake_up(x)
#endif

#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;                                                          \
})

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

/**
 * wait_event_killable - 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_KILLABLE) 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_killable(wq, condition)                              \
({                                                                      \
        int __ret = 0;                                                  \
        if (!(condition))                                               \
                __wait_event_killable(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.
 */
extern void sleep_on(wait_queue_head_t *q);
extern long sleep_on_timeout(wait_queue_head_t *q,
                                      signed long timeout);
extern void interruptible_sleep_on(wait_queue_head_t *q);
extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
                                           signed long timeout);

/*
 * Waitqueues which are removed from the waitqueue_head at wakeup time
 */
void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
void 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