linux/include/linux/completion.h
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   1#ifndef __LINUX_COMPLETION_H
   2#define __LINUX_COMPLETION_H
   3
   4/*
   5 * (C) Copyright 2001 Linus Torvalds
   6 *
   7 * Atomic wait-for-completion handler data structures.
   8 * See kernel/sched.c for details.
   9 */
  10
  11#include <linux/wait.h>
  12
  13/*
  14 * struct completion - structure used to maintain state for a "completion"
  15 *
  16 * This is the opaque structure used to maintain the state for a "completion".
  17 * Completions currently use a FIFO to queue threads that have to wait for
  18 * the "completion" event.
  19 *
  20 * See also:  complete(), wait_for_completion() (and friends _timeout,
  21 * _interruptible, _interruptible_timeout, and _killable), init_completion(),
  22 * and macros DECLARE_COMPLETION(), DECLARE_COMPLETION_ONSTACK(), and
  23 * INIT_COMPLETION().
  24 */
  25struct completion {
  26        unsigned int done;
  27        wait_queue_head_t wait;
  28};
  29
  30#define COMPLETION_INITIALIZER(work) \
  31        { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
  32
  33#define COMPLETION_INITIALIZER_ONSTACK(work) \
  34        ({ init_completion(&work); work; })
  35
  36/**
  37 * DECLARE_COMPLETION - declare and initialize a completion structure
  38 * @work:  identifier for the completion structure
  39 *
  40 * This macro declares and initializes a completion structure. Generally used
  41 * for static declarations. You should use the _ONSTACK variant for automatic
  42 * variables.
  43 */
  44#define DECLARE_COMPLETION(work) \
  45        struct completion work = COMPLETION_INITIALIZER(work)
  46
  47/*
  48 * Lockdep needs to run a non-constant initializer for on-stack
  49 * completions - so we use the _ONSTACK() variant for those that
  50 * are on the kernel stack:
  51 */
  52/**
  53 * DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure
  54 * @work:  identifier for the completion structure
  55 *
  56 * This macro declares and initializes a completion structure on the kernel
  57 * stack.
  58 */
  59#ifdef CONFIG_LOCKDEP
  60# define DECLARE_COMPLETION_ONSTACK(work) \
  61        struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
  62#else
  63# define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
  64#endif
  65
  66/**
  67 * init_completion - Initialize a dynamically allocated completion
  68 * @x:  completion structure that is to be initialized
  69 *
  70 * This inline function will initialize a dynamically created completion
  71 * structure.
  72 */
  73static inline void init_completion(struct completion *x)
  74{
  75        x->done = 0;
  76        init_waitqueue_head(&x->wait);
  77}
  78
  79extern void wait_for_completion(struct completion *);
  80extern int wait_for_completion_interruptible(struct completion *x);
  81extern int wait_for_completion_killable(struct completion *x);
  82extern unsigned long wait_for_completion_timeout(struct completion *x,
  83                                                   unsigned long timeout);
  84extern long wait_for_completion_interruptible_timeout(
  85        struct completion *x, unsigned long timeout);
  86extern long wait_for_completion_killable_timeout(
  87        struct completion *x, unsigned long timeout);
  88extern bool try_wait_for_completion(struct completion *x);
  89extern bool completion_done(struct completion *x);
  90
  91extern void complete(struct completion *);
  92extern void complete_all(struct completion *);
  93
  94/**
  95 * INIT_COMPLETION - reinitialize a completion structure
  96 * @x:  completion structure to be reinitialized
  97 *
  98 * This macro should be used to reinitialize a completion structure so it can
  99 * be reused. This is especially important after complete_all() is used.
 100 */
 101#define INIT_COMPLETION(x)      ((x).done = 0)
 102
 103
 104#endif
 105
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