[people/arne_f/kernel.git] / include / linux / wait.h

#ifndef _LINUX_WAIT_H
#define _LINUX_WAIT_H
/*
 * Linux wait queue related types and methods
 */
#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_entry wait_queue_entry_t;

typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);

/* wait_queue_entry::flags */
#define WQ_FLAG_EXCLUSIVE       0x01
#define WQ_FLAG_WOKEN           0x02

/*
 * A single wait-queue entry structure:
 */
struct wait_queue_entry {
        unsigned int            flags;
        void                    *private;
        wait_queue_func_t       func;
        struct list_head        task_list;
};

struct wait_bit_key {
        void                    *flags;
        int                     bit_nr;
#define WAIT_ATOMIC_T_BIT_NR    -1
        unsigned long           timeout;
};

struct wait_bit_queue {
        struct wait_bit_key     key;
        struct wait_queue_entry 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)                                    \
        struct wait_queue_entry 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, }

#define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
        { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }

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(struct wait_queue_entry *wq_entry, struct task_struct *p)
{
        wq_entry->flags         = 0;
        wq_entry->private       = p;
        wq_entry->func          = default_wake_function;
}

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

/**
 * waitqueue_active -- locklessly test for waiters on the queue
 * @q: the waitqueue to test for waiters
 *
 * returns true if the wait list is not empty
 *
 * NOTE: this function is lockless and requires care, incorrect usage _will_
 * lead to sporadic and non-obvious failure.
 *
 * Use either while holding wait_queue_head_t::lock or when used for wakeups
 * with an extra smp_mb() like:
 *
 *      CPU0 - waker                    CPU1 - waiter
 *
 *                                      for (;;) {
 *      @cond = true;                     prepare_to_wait(&wq, &wait, state);
 *      smp_mb();                         // smp_mb() from set_current_state()
 *      if (waitqueue_active(wq))         if (@cond)
 *        wake_up(wq);                      break;
 *                                        schedule();
 *                                      }
 *                                      finish_wait(&wq, &wait);
 *
 * Because without the explicit smp_mb() it's possible for the
 * waitqueue_active() load to get hoisted over the @cond store such that we'll
 * observe an empty wait list while the waiter might not observe @cond.
 *
 * Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
 * which (when the lock is uncontended) are of roughly equal cost.
 */
static inline int waitqueue_active(wait_queue_head_t *q)
{
        return !list_empty(&q->task_list);
}

/**
 * wq_has_sleeper - check if there are any waiting processes
 * @wq: wait queue head
 *
 * Returns true if wq has waiting processes
 *
 * Please refer to the comment for waitqueue_active.
 */
static inline bool wq_has_sleeper(wait_queue_head_t *wq)
{
        /*
         * We need to be sure we are in sync with the
         * add_wait_queue modifications to the wait queue.
         *
         * This memory barrier should be paired with one on the
         * waiting side.
         */
        smp_mb();
        return waitqueue_active(wq);
}

extern void add_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry);
extern void add_wait_queue_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry);
extern void remove_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry);

static inline void __add_wait_queue(wait_queue_head_t *head, struct wait_queue_entry *wq_entry)
{
        list_add(&wq_entry->task_list, &head->task_list);
}

/*
 * Used for wake-one threads:
 */
static inline void
__add_wait_queue_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry)
{
        wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
        __add_wait_queue(q, wq_entry);
}

static inline void __add_wait_queue_entry_tail(wait_queue_head_t *head, struct wait_queue_entry *wq_entry)
{
        list_add_tail(&wq_entry->task_list, &head->task_list);
}

static inline void
__add_wait_queue_entry_tail_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry)
{
        wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
        __add_wait_queue_entry_tail(q, wq_entry);
}

static inline void
__remove_wait_queue(wait_queue_head_t *head, struct wait_queue_entry *wq_entry)
{
        list_del(&wq_entry->task_list);
}

typedef int wait_bit_action_f(struct wait_bit_key *, int mode);
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 *, wait_bit_action_f *, unsigned);
int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
void wake_up_bit(void *, int);
void wake_up_atomic_t(atomic_t *);
int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), 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_cond_timeout(condition)                                 \
({                                                                      \
        bool __cond = (condition);                                      \
        if (__cond && !__ret)                                           \
                __ret = 1;                                              \
        __cond || !__ret;                                               \
})

#define ___wait_is_interruptible(state)                                 \
        (!__builtin_constant_p(state) ||                                \
                state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)  \

extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);

/*
 * The below macro ___wait_event() has an explicit shadow of the __ret
 * variable when used from the wait_event_*() macros.
 *
 * This is so that both can use the ___wait_cond_timeout() construct
 * to wrap the condition.
 *
 * The type inconsistency of the wait_event_*() __ret variable is also
 * on purpose; we use long where we can return timeout values and int
 * otherwise.
 */

#define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
({                                                                      \
        __label__ __out;                                                \
        struct wait_queue_entry __wq_entry;                             \
        long __ret = ret;       /* explicit shadow */                   \
                                                                        \
        init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0);\
        for (;;) {                                                      \
                long __int = prepare_to_wait_event(&wq, &__wq_entry, state);\
                                                                        \
                if (condition)                                          \
                        break;                                          \
                                                                        \
                if (___wait_is_interruptible(state) && __int) {         \
                        __ret = __int;                                  \
                        goto __out;                                     \
                }                                                       \
                                                                        \
                cmd;                                                    \
        }                                                               \
        finish_wait(&wq, &__wq_entry);                                  \
__out:  __ret;                                                          \
})

#define __wait_event(wq, condition)                                     \
        (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
                            schedule())

/**
 * 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 {                                                                    \
        might_sleep();                                                  \
        if (condition)                                                  \
                break;                                                  \
        __wait_event(wq, condition);                                    \
} while (0)

#define __io_wait_event(wq, condition)                                  \
        (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
                            io_schedule())

/*
 * io_wait_event() -- like wait_event() but with io_schedule()
 */
#define io_wait_event(wq, condition)                                    \
do {                                                                    \
        might_sleep();                                                  \
        if (condition)                                                  \
                break;                                                  \
        __io_wait_event(wq, condition);                                 \
} while (0)

#define __wait_event_freezable(wq, condition)                           \
        ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
                            schedule(); try_to_freeze())

/**
 * wait_event_freezable - sleep (or freeze) 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 -- so as not to contribute
 * to system load) 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_freezable(wq, condition)                             \
({                                                                      \
        int __ret = 0;                                                  \
        might_sleep();                                                  \
        if (!(condition))                                               \
                __ret = __wait_event_freezable(wq, condition);          \
        __ret;                                                          \
})

#define __wait_event_timeout(wq, condition, timeout)                    \
        ___wait_event(wq, ___wait_cond_timeout(condition),              \
                      TASK_UNINTERRUPTIBLE, 0, timeout,                 \
                      __ret = schedule_timeout(__ret))

/**
 * 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.
 *
 * Returns:
 * 0 if the @condition evaluated to %false after the @timeout elapsed,
 * 1 if the @condition evaluated to %true after 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;                                           \
        might_sleep();                                                  \
        if (!___wait_cond_timeout(condition))                           \
                __ret = __wait_event_timeout(wq, condition, timeout);   \
        __ret;                                                          \
})

#define __wait_event_freezable_timeout(wq, condition, timeout)          \
        ___wait_event(wq, ___wait_cond_timeout(condition),              \
                      TASK_INTERRUPTIBLE, 0, timeout,                   \
                      __ret = schedule_timeout(__ret); try_to_freeze())

/*
 * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
 * increasing load and is freezable.
 */
#define wait_event_freezable_timeout(wq, condition, timeout)            \
({                                                                      \
        long __ret = timeout;                                           \
        might_sleep();                                                  \
        if (!___wait_cond_timeout(condition))                           \
                __ret = __wait_event_freezable_timeout(wq, condition, timeout); \
        __ret;                                                          \
})

#define __wait_event_exclusive_cmd(wq, condition, cmd1, cmd2)           \
        (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 1, 0,  \
                            cmd1; schedule(); cmd2)
/*
 * Just like wait_event_cmd(), except it sets exclusive flag
 */
#define wait_event_exclusive_cmd(wq, condition, cmd1, cmd2)             \
do {                                                                    \
        if (condition)                                                  \
                break;                                                  \
        __wait_event_exclusive_cmd(wq, condition, cmd1, cmd2);          \
} while (0)

#define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
        (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
                            cmd1; schedule(); cmd2)

/**
 * wait_event_cmd - sleep until a condition gets true
 * @wq: the waitqueue to wait on
 * @condition: a C expression for the event to wait for
 * @cmd1: the command will be executed before sleep
 * @cmd2: the command will be executed after 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.
 */
#define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
do {                                                                    \
        if (condition)                                                  \
                break;                                                  \
        __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
} while (0)

#define __wait_event_interruptible(wq, condition)                       \
        ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
                      schedule())

/**
 * 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;                                                  \
        might_sleep();                                                  \
        if (!(condition))                                               \
                __ret = __wait_event_interruptible(wq, condition);      \
        __ret;                                                          \
})

#define __wait_event_interruptible_timeout(wq, condition, timeout)      \
        ___wait_event(wq, ___wait_cond_timeout(condition),              \
                      TASK_INTERRUPTIBLE, 0, timeout,                   \
                      __ret = schedule_timeout(__ret))

/**
 * 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 @condition evaluated to %false after the @timeout elapsed,
 * 1 if the @condition evaluated to %true after the @timeout elapsed,
 * the remaining jiffies (at least 1) if the @condition evaluated
 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 * interrupted by a signal.
 */
#define wait_event_interruptible_timeout(wq, condition, timeout)        \
({                                                                      \
        long __ret = timeout;                                           \
        might_sleep();                                                  \
        if (!___wait_cond_timeout(condition))                           \
                __ret = __wait_event_interruptible_timeout(wq,          \
                                                condition, timeout);    \
        __ret;                                                          \
})

#define __wait_event_hrtimeout(wq, condition, timeout, state)           \
({                                                                      \
        int __ret = 0;                                                  \
        struct hrtimer_sleeper __t;                                     \
                                                                        \
        hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
                              HRTIMER_MODE_REL);                        \
        hrtimer_init_sleeper(&__t, current);                            \
        if ((timeout) != KTIME_MAX)                             \
                hrtimer_start_range_ns(&__t.timer, timeout,             \
                                       current->timer_slack_ns,         \
                                       HRTIMER_MODE_REL);               \
                                                                        \
        __ret = ___wait_event(wq, condition, state, 0, 0,               \
                if (!__t.task) {                                        \
                        __ret = -ETIME;                                 \
                        break;                                          \
                }                                                       \
                schedule());                                            \
                                                                        \
        hrtimer_cancel(&__t.timer);                                     \
        destroy_hrtimer_on_stack(&__t.timer);                           \
        __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;                                                  \
        might_sleep();                                                  \
        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;                                                 \
        might_sleep();                                                  \
        if (!(condition))                                               \
                __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
                                               TASK_INTERRUPTIBLE);     \
        __ret;                                                          \
})

#define __wait_event_interruptible_exclusive(wq, condition)             \
        ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
                      schedule())

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

#define __wait_event_killable_exclusive(wq, condition)                  \
        ___wait_event(wq, condition, TASK_KILLABLE, 1, 0,               \
                      schedule())

#define wait_event_killable_exclusive(wq, condition)                    \
({                                                                      \
        int __ret = 0;                                                  \
        might_sleep();                                                  \
        if (!(condition))                                               \
                __ret = __wait_event_killable_exclusive(wq, condition); \
        __ret;                                                          \
})


#define __wait_event_freezable_exclusive(wq, condition)                 \
        ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
                        schedule(); try_to_freeze())

#define wait_event_freezable_exclusive(wq, condition)                   \
({                                                                      \
        int __ret = 0;                                                  \
        might_sleep();                                                  \
        if (!(condition))                                               \
                __ret = __wait_event_freezable_exclusive(wq, condition);\
        __ret;                                                          \
})

extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);

#define __wait_event_interruptible_locked(wq, condition, exclusive, fn) \
({                                                                      \
        int __ret;                                                      \
        DEFINE_WAIT(__wait);                                            \
        if (exclusive)                                                  \
                __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
        do {                                                            \
                __ret = fn(&(wq), &__wait);                             \
                if (__ret)                                              \
                        break;                                          \
        } 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, do_wait_intr))

/**
 * 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, do_wait_intr_irq))

/**
 * 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, do_wait_intr))

/**
 * 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, do_wait_intr_irq))


#define __wait_event_killable(wq, condition)                            \
        ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())

/**
 * 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;                                                  \
        might_sleep();                                                  \
        if (!(condition))                                               \
                __ret = __wait_event_killable(wq, condition);           \
        __ret;                                                          \
})


#define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
        (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
                            spin_unlock_irq(&lock);                     \
                            cmd;                                        \
                            schedule();                                 \
                            spin_lock_irq(&lock))

/**
 * 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, cmd)   \
        ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
                      spin_unlock_irq(&lock);                           \
                      cmd;                                              \
                      schedule();                                       \
                      spin_lock_irq(&lock))

/**
 * 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))                                               \
                __ret = __wait_event_interruptible_lock_irq(wq,         \
                                                condition, lock, 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))                                               \
                __ret = __wait_event_interruptible_lock_irq(wq,         \
                                                condition, lock,);      \
        __ret;                                                          \
})

#define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
                                                    lock, timeout)      \
        ___wait_event(wq, ___wait_cond_timeout(condition),              \
                      TASK_INTERRUPTIBLE, 0, timeout,                   \
                      spin_unlock_irq(&lock);                           \
                      __ret = schedule_timeout(__ret);                  \
                      spin_lock_irq(&lock));

/**
 * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
 *              true or a timeout elapses. 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.
 * @timeout: timeout, in jiffies
 *
 * 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 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_lock_irq_timeout(wq, condition, lock,  \
                                                  timeout)              \
({                                                                      \
        long __ret = timeout;                                           \
        if (!___wait_cond_timeout(condition))                           \
                __ret = __wait_event_interruptible_lock_irq_timeout(    \
                                        wq, condition, lock, timeout);  \
        __ret;                                                          \
})

/*
 * Waitqueues which are removed from the waitqueue_head at wakeup time
 */
void prepare_to_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state);
void prepare_to_wait_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state);
long prepare_to_wait_event(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state);
void finish_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry);
long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);

#define DEFINE_WAIT_FUNC(name, function)                                \
        struct wait_queue_entry 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)


extern int bit_wait(struct wait_bit_key *, int);
extern int bit_wait_io(struct wait_bit_key *, int);
extern int bit_wait_timeout(struct wait_bit_key *, int);
extern int bit_wait_io_timeout(struct wait_bit_key *, int);

/**
 * 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
 * @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.
 * Returned value will be zero if the bit was cleared, or non-zero
 * if the process received a signal and the mode permitted wakeup
 * on that signal.
 */
static inline int
wait_on_bit(unsigned long *word, int bit, unsigned mode)
{
        might_sleep();
        if (!test_bit(bit, word))
                return 0;
        return out_of_line_wait_on_bit(word, bit,
                                       bit_wait,
                                       mode);
}

/**
 * wait_on_bit_io - 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
 * @mode: the task state to sleep in
 *
 * Use the standard hashed waitqueue table to wait for a bit
 * to be cleared.  This is similar to wait_on_bit(), but calls
 * io_schedule() instead of schedule() for the actual waiting.
 *
 * Returned value will be zero if the bit was cleared, or non-zero
 * if the process received a signal and the mode permitted wakeup
 * on that signal.
 */
static inline int
wait_on_bit_io(unsigned long *word, int bit, unsigned mode)
{
        might_sleep();
        if (!test_bit(bit, word))
                return 0;
        return out_of_line_wait_on_bit(word, bit,
                                       bit_wait_io,
                                       mode);
}

/**
 * wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses
 * @word: the word being waited on, a kernel virtual address
 * @bit: the bit of the word being waited on
 * @mode: the task state to sleep in
 * @timeout: timeout, in jiffies
 *
 * Use the standard hashed waitqueue table to wait for a bit
 * to be cleared. This is similar to wait_on_bit(), except also takes a
 * timeout parameter.
 *
 * Returned value will be zero if the bit was cleared before the
 * @timeout elapsed, or non-zero if the @timeout elapsed or process
 * received a signal and the mode permitted wakeup on that signal.
 */
static inline int
wait_on_bit_timeout(unsigned long *word, int bit, unsigned mode,
                    unsigned long timeout)
{
        might_sleep();
        if (!test_bit(bit, word))
                return 0;
        return out_of_line_wait_on_bit_timeout(word, bit,
                                               bit_wait_timeout,
                                               mode, timeout);
}

/**
 * wait_on_bit_action - 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
 *
 * Use the standard hashed waitqueue table to wait for a bit
 * to be cleared, and allow the waiting action to be specified.
 * This is like wait_on_bit() but allows fine control of how the waiting
 * is done.
 *
 * Returned value will be zero if the bit was cleared, or non-zero
 * if the process received a signal and the mode permitted wakeup
 * on that signal.
 */
static inline int
wait_on_bit_action(unsigned long *word, int bit, wait_bit_action_f *action,
                   unsigned mode)
{
        might_sleep();
        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
 * @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.
 *
 * Returns zero if the bit was (eventually) found to be clear and was
 * set.  Returns non-zero if a signal was delivered to the process and
 * the @mode allows that signal to wake the process.
 */
static inline int
wait_on_bit_lock(unsigned long *word, int bit, unsigned mode)
{
        might_sleep();
        if (!test_and_set_bit(bit, word))
                return 0;
        return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
}

/**
 * wait_on_bit_lock_io - 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
 * @mode: the task state to sleep in
 *
 * Use the standard hashed waitqueue table to wait for a bit
 * to be cleared and then to atomically set it.  This is similar
 * to wait_on_bit(), but calls io_schedule() instead of schedule()
 * for the actual waiting.
 *
 * Returns zero if the bit was (eventually) found to be clear and was
 * set.  Returns non-zero if a signal was delivered to the process and
 * the @mode allows that signal to wake the process.
 */
static inline int
wait_on_bit_lock_io(unsigned long *word, int bit, unsigned mode)
{
        might_sleep();
        if (!test_and_set_bit(bit, word))
                return 0;
        return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
}

/**
 * wait_on_bit_lock_action - 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
 *
 * Use the standard hashed waitqueue table to wait for a bit
 * to be cleared and then to set it, and allow the waiting action
 * to be specified.
 * This is like wait_on_bit() but allows fine control of how the waiting
 * is done.
 *
 * Returns zero if the bit was (eventually) found to be clear and was
 * set.  Returns non-zero if a signal was delivered to the process and
 * the @mode allows that signal to wake the process.
 */
static inline int
wait_on_bit_lock_action(unsigned long *word, int bit, wait_bit_action_f *action,
                        unsigned mode)
{
        might_sleep();
        if (!test_and_set_bit(bit, word))
                return 0;
        return out_of_line_wait_on_bit_lock(word, bit, action, mode);
}

/**
 * wait_on_atomic_t - Wait for an atomic_t to become 0
 * @val: The atomic value being waited on, a kernel virtual address
 * @action: the function used to sleep, which may take special actions
 * @mode: the task state to sleep in
 *
 * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
 * the purpose of getting a waitqueue, but we set the key to a bit number
 * outside of the target 'word'.
 */
static inline
int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
{
        might_sleep();
        if (atomic_read(val) == 0)
                return 0;
        return out_of_line_wait_on_atomic_t(val, action, mode);
}

#endif /* _LINUX_WAIT_H */