#ifndef __LINUX_COMPLETION_H
  #define __LINUX_COMPLETION_H
  
  /*
   * (C) Copyright 2001 Linus Torvalds
   *
   * Atomic wait-for-completion handler data structures.
   * See kernel/sched.c for details.
   */
  
  #include <linux/wait.h>

  /*

   * struct completion - structure used to maintain state for a "completion"
   *
   * This is the opaque structure used to maintain the state for a "completion".
   * Completions currently use a FIFO to queue threads that have to wait for
   * the "completion" event.
   *
   * See also:  complete(), wait_for_completion() (and friends _timeout,
   * _interruptible, _interruptible_timeout, and _killable), init_completion(),
   * and macros DECLARE_COMPLETION(), DECLARE_COMPLETION_ONSTACK(), and
   * INIT_COMPLETION().
   */

  struct completion {
  	unsigned int done;
  	wait_queue_head_t wait;
  };
  
  #define COMPLETION_INITIALIZER(work) \
  	{ 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }

  #define COMPLETION_INITIALIZER_ONSTACK(work) \
  	({ init_completion(&work); work; })

  /**

   * DECLARE_COMPLETION - declare and initialize a completion structure

   * @work:  identifier for the completion structure
   *
   * This macro declares and initializes a completion structure. Generally used
   * for static declarations. You should use the _ONSTACK variant for automatic
   * variables.
   */

  #define DECLARE_COMPLETION(work) \
  	struct completion work = COMPLETION_INITIALIZER(work)

  /*
   * Lockdep needs to run a non-constant initializer for on-stack
   * completions - so we use the _ONSTACK() variant for those that
   * are on the kernel stack:
   */

  /**

   * DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure

   * @work:  identifier for the completion structure
   *
   * This macro declares and initializes a completion structure on the kernel
   * stack.
   */

  #ifdef CONFIG_LOCKDEP
  # define DECLARE_COMPLETION_ONSTACK(work) \

  	struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)

  #else
  # define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
  #endif

  /**

   * init_completion - Initialize a dynamically allocated completion

   * @x:  completion structure that is to be initialized
   *
   * This inline function will initialize a dynamically created completion
   * structure.
   */

  static inline void init_completion(struct completion *x)
  {
  	x->done = 0;
  	init_waitqueue_head(&x->wait);
  }

  extern void wait_for_completion(struct completion *);
  extern int wait_for_completion_interruptible(struct completion *x);

  extern int wait_for_completion_killable(struct completion *x);

  extern unsigned long wait_for_completion_timeout(struct completion *x,
  						   unsigned long timeout);

  extern long wait_for_completion_interruptible_timeout(
  	struct completion *x, unsigned long timeout);
  extern long wait_for_completion_killable_timeout(
  	struct completion *x, unsigned long timeout);

  extern bool try_wait_for_completion(struct completion *x);
  extern bool completion_done(struct completion *x);

  
  extern void complete(struct completion *);
  extern void complete_all(struct completion *);

  /**

   * INIT_COMPLETION - reinitialize a completion structure

   * @x:  completion structure to be reinitialized
   *
   * This macro should be used to reinitialize a completion structure so it can
   * be reused. This is especially important after complete_all() is used.
   */

  #define INIT_COMPLETION(x)	((x).done = 0)

  #endif