#ifndef _LINUX_WAIT_H
#define _LINUX_WAIT_H


#include <linux/list.h>
#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <asm/current.h>
#include <uapi/linux/wait.h>

typedef struct __wait_queue wait_queue_t;
typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, 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, const char *name, struct lock_class_key *);

#define init_waitqueue_head(q)                          \
        do {                                            \
                static struct lock_class_key __key;     \
                                                        \
                __init_waitqueue_head((q), #q, &__key); \
        } while (0)

#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);
}

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_exclusive(wait_queue_head_t *q,
                                              wait_queue_t *wait)
{
        wait->flags |= WQ_FLAG_EXCLUSIVE;
        __add_wait_queue(q, wait);
}

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 __add_wait_queue_tail_exclusive(wait_queue_head_t *q,
                                              wait_queue_t *wait)
{
        wait->flags |= WQ_FLAG_EXCLUSIVE;
        __add_wait_queue_tail(q, wait);
}

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);
void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
                        void *key);
void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
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, 1)
#define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)

#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)

/*
 * Wakeup macros to be used to report events to the targets.
 */
#define wake_up_poll(x, m)                              \
        __wake_up(x, TASK_NORMAL, 1, (void *) (m))
#define wake_up_locked_poll(x, m)                               \
        __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
#define wake_up_interruptible_poll(x, m)                        \
        __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
#define wake_up_interruptible_sync_poll(x, m)                           \
        __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))

#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;                                          \
        }                                                               \
        if (!ret && (condition))                                        \
                ret = 1;                                                \
        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, or the remaining
 * jiffies (at least 1) 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;                                                  \
        }                                                               \
        if (!ret && (condition))                                        \
                ret = 1;                                                \
        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.
 *
 * Returns:
 * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
 * a signal, or the remaining jiffies (at least 1) 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_hrtimeout(wq, condition, timeout, state)           \
({                                                                      \
        int __ret = 0;                                                  \
        DEFINE_WAIT(__wait);                                            \
        struct hrtimer_sleeper __t;                                     \
                                                                        \
        hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
                              HRTIMER_MODE_REL);                        \
        hrtimer_init_sleeper(&__t, current);                            \
        if ((timeout).tv64 != KTIME_MAX)                                \
                hrtimer_start_range_ns(&__t.timer, timeout,             \
                                       current->timer_slack_ns,         \
                                       HRTIMER_MODE_REL);               \
                                                                        \
        for (;;) {                                                      \
                prepare_to_wait(&wq, &__wait, state);                   \
                if (condition)                                          \
                        break;                                          \
                if (state == TASK_INTERRUPTIBLE &&                      \
                    signal_pending(current)) {                          \
                        __ret = -ERESTARTSYS;                           \
                        break;                                          \
                }                                                       \
                if (!__t.task) {                                        \
                        __ret = -ETIME;                                 \
                        break;                                          \
                }                                                       \
                schedule();                                             \
        }                                                               \
                                                                        \
        hrtimer_cancel(&__t.timer);                                     \
        destroy_hrtimer_on_stack(&__t.timer);                           \
        finish_wait(&wq, &__wait);                                      \
        __ret;                                                          \
})

/**
 * wait_event_hrtimeout - 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, as a ktime_t
 *
 * The process is put to sleep (TASK_UNINTERRUPTIBLE) 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 @condition became true, or -ETIME if the timeout
 * elapsed.
 */
#define wait_event_hrtimeout(wq, condition, timeout)                    \
({                                                                      \
        int __ret = 0;                                                  \
        if (!(condition))                                               \
                __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
                                               TASK_UNINTERRUPTIBLE);   \
        __ret;                                                          \
})

/**
 * wait_event_interruptible_hrtimeout - 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, as a ktime_t
 *
 * 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 @condition became true, -ERESTARTSYS if it was
 * interrupted by a signal, or -ETIME if the timeout elapsed.
 */
#define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
({                                                                      \
        long __ret = 0;                                                 \
        if (!(condition))                                               \
                __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
                                               TASK_INTERRUPTIBLE);     \
        __ret;                                                          \
})

#define __wait_event_interruptible_exclusive(wq, condition, ret)        \
do {                                                                    \
        DEFINE_WAIT(__wait);                                            \
                                                                        \
        for (;;) {                                                      \
                prepare_to_wait_exclusive(&wq, &__wait,                 \
                                        TASK_INTERRUPTIBLE);            \
                if (condition) {                                        \
                        finish_wait(&wq, &__wait);                      \
                        break;                                          \
                }                                                       \
                if (!signal_pending(current)) {                         \
                        schedule();                                     \
                        continue;                                       \
                }                                                       \
                ret = -ERESTARTSYS;                                     \
                abort_exclusive_wait(&wq, &__wait,                      \
                                TASK_INTERRUPTIBLE, NULL);              \
                break;                                                  \
        }                                                               \
} 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_interruptible_locked(wq, condition, exclusive, irq) \
({                                                                      \
        int __ret = 0;                                                  \
        DEFINE_WAIT(__wait);                                            \
        if (exclusive)                                                  \
                __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
        do {                                                            \
                if (likely(list_empty(&__wait.task_list)))              \
                        __add_wait_queue_tail(&(wq), &__wait);          \
                set_current_state(TASK_INTERRUPTIBLE);                  \
                if (signal_pending(current)) {                          \
                        __ret = -ERESTARTSYS;                           \
                        break;                                          \
                }                                                       \
                if (irq)                                                \
                        spin_unlock_irq(&(wq).lock);                    \
                else                                                    \
                        spin_unlock(&(wq).lock);                        \
                schedule();                                             \
                if (irq)                                                \
                        spin_lock_irq(&(wq).lock);                      \
                else                                                    \
                        spin_lock(&(wq).lock);                          \
        } while (!(condition));                                         \
        __remove_wait_queue(&(wq), &__wait);                            \
        __set_current_state(TASK_RUNNING);                              \
        __ret;                                                          \
})


/**
 * wait_event_interruptible_locked - 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.
 *
 * It must be called with wq.lock being held.  This spinlock is
 * unlocked while sleeping but @condition testing is done while lock
 * is held and when this macro exits the lock is held.
 *
 * The lock is locked/unlocked using spin_lock()/spin_unlock()
 * functions which must match the way they are locked/unlocked outside
 * of this macro.
 *
 * wake_up_locked() 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_locked(wq, condition)                  \
        ((condition)                                                    \
         ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))

/**
 * wait_event_interruptible_locked_irq - 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.
 *
 * It must be called with wq.lock being held.  This spinlock is
 * unlocked while sleeping but @condition testing is done while lock
 * is held and when this macro exits the lock is held.
 *
 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 * functions which must match the way they are locked/unlocked outside
 * of this macro.
 *
 * wake_up_locked() 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_locked_irq(wq, condition)              \
        ((condition)                                                    \
         ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))

/**
 * wait_event_interruptible_exclusive_locked - sleep exclusively 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.
 *
 * It must be called with wq.lock being held.  This spinlock is
 * unlocked while sleeping but @condition testing is done while lock
 * is held and when this macro exits the lock is held.
 *
 * The lock is locked/unlocked using spin_lock()/spin_unlock()
 * functions which must match the way they are locked/unlocked outside
 * of this macro.
 *
 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 * set thus when other process waits process on the list if this
 * process is awaken further processes are not considered.
 *
 * wake_up_locked() 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_exclusive_locked(wq, condition)        \
        ((condition)                                                    \
         ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))

/**
 * wait_event_interruptible_exclusive_locked_irq - 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.
 *
 * It must be called with wq.lock being held.  This spinlock is
 * unlocked while sleeping but @condition testing is done while lock
 * is held and when this macro exits the lock is held.
 *
 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 * functions which must match the way they are locked/unlocked outside
 * of this macro.
 *
 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 * set thus when other process waits process on the list if this
 * process is awaken further processes are not considered.
 *
 * wake_up_locked() 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_exclusive_locked_irq(wq, condition)    \
        ((condition)                                                    \
         ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))



#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;                                                          \
})


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

/**
 * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 *                           condition is checked under the lock. This
 *                           is expected to be called with the lock
 *                           taken.
 * @wq: the waitqueue to wait on
 * @condition: a C expression for the event to wait for
 * @lock: a locked spinlock_t, which will be released before cmd
 *        and schedule() and reacquired afterwards.
 * @cmd: a command which is invoked outside the critical section before
 *       sleep
 *
 * 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.
 *
 * This is supposed to be called while holding the lock. The lock is
 * dropped before invoking the cmd and going to sleep and is reacquired
 * afterwards.
 */
#define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
do {                                                                    \
        if (condition)                                                  \
                break;                                                  \
        __wait_event_lock_irq(wq, condition, lock, cmd);                \
} while (0)

/**
 * wait_event_lock_irq - sleep until a condition gets true. The
 *                       condition is checked under the lock. This
 *                       is expected to be called with the lock
 *                       taken.
 * @wq: the waitqueue to wait on
 * @condition: a C expression for the event to wait for
 * @lock: a locked spinlock_t, which will be released before schedule()
 *        and reacquired afterwards.
 *
 * 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.
 *
 * This is supposed to be called while holding the lock. The lock is
 * dropped before going to sleep and is reacquired afterwards.
 */
#define wait_event_lock_irq(wq, condition, lock)                        \
do {                                                                    \
        if (condition)                                                  \
                break;                                                  \
        __wait_event_lock_irq(wq, condition, lock, );                   \
} while (0)


#define __wait_event_interruptible_lock_irq(wq, condition,              \
                                            lock, ret, cmd)             \
do {                                                                    \
        DEFINE_WAIT(__wait);                                            \
                                                                        \
        for (;;) {                                                      \
                prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
                if (condition)                                          \
                        break;                                          \
                if (signal_pending(current)) {                          \
                        ret = -ERESTARTSYS;                             \
                        break;                                          \
                }                                                       \
                spin_unlock_irq(&lock);                                 \
                cmd;                                                    \
                schedule();                                             \
                spin_lock_irq(&lock);                                   \
        }                                                               \
        finish_wait(&wq, &__wait);                                      \
} while (0)

/**
 * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 *              The condition is checked under the lock. This is expected to
 *              be called with the lock taken.
 * @wq: the waitqueue to wait on
 * @condition: a C expression for the event to wait for
 * @lock: a locked spinlock_t, which will be released before cmd and
 *        schedule() and reacquired afterwards.
 * @cmd: a command which is invoked outside the critical section before
 *       sleep
 *
 * 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.
 *
 * This is supposed to be called while holding the lock. The lock is
 * dropped before invoking the cmd and going to sleep and is reacquired
 * afterwards.
 *
 * The macro will return -ERESTARTSYS if it was interrupted by a signal
 * and 0 if @condition evaluated to true.
 */
#define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
({                                                                      \
        int __ret = 0;                                                  \
                                                                        \
        if (!(condition))                                               \
                __wait_event_interruptible_lock_irq(wq, condition,      \
                                                    lock, __ret, cmd);  \
        __ret;                                                          \
})

/**
 * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 *              The condition is checked under the lock. This is expected
 *              to be called with the lock taken.
 * @wq: the waitqueue to wait on
 * @condition: a C expression for the event to wait for
 * @lock: a locked spinlock_t, which will be released before schedule()
 *        and reacquired afterwards.
 *
 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 * @condition evaluates to true or 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.
 *
 * This is supposed to be called while holding the lock. The lock is
 * dropped before going to sleep and is reacquired afterwards.
 *
 * The macro will return -ERESTARTSYS if it was interrupted by a signal
 * and 0 if @condition evaluated to true.
 */
#define wait_event_interruptible_lock_irq(wq, condition, lock)          \
({                                                                      \
        int __ret = 0;                                                  \
                                                                        \
        if (!(condition))                                               \
                __wait_event_interruptible_lock_irq(wq, condition,      \
                                                    lock, __ret, );     \
        __ret;                                                          \
})


/*
 * 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);
void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
                        unsigned int mode, void *key);
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_FUNC(name, function)                                \
        wait_queue_t name = {                                           \
                .private        = current,                              \
                .func           = function,                             \
                .task_list      = LIST_HEAD_INIT((name).task_list),     \
        }

#define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)

#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);                     \
                (wait)->flags = 0;                                      \
        } 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