#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 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);

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

  struct __wait_queue {

  	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;
  	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, }

  #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(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;

  }

  /**
   * 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, 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);
  }

  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(wait_queue_t *__wait, 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;						\

  	wait_queue_t __wait;						\

  	long __ret = ret;	/* explicit shadow */			\

  									\

  	init_wait_entry(&__wait, exclusive ? WQ_FLAG_EXCLUSIVE : 0);	\

  	for (;;) {							\

  		long __int = prepare_to_wait_event(&wq, &__wait, state);\

  									\
  		if (condition)						\
  			break;						\
  									\

  		if (___wait_is_interruptible(state) && __int) {		\
  			__ret = __int;					\

  			goto __out;					\

  		}							\
  									\
  		cmd;							\
  	}								\
  	finish_wait(&wq, &__wait);					\

  __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).tv64 != 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;								\
  })

  #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)				\
  	___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, wait_queue_t *wait, int state);
  void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);

  long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);

  void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);

  long wait_woken(wait_queue_t *wait, unsigned mode, long timeout);
  int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, 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)

  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 */