LXR linux/include/linux/completion.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef __LINUX_COMPLETION_H
   3#define __LINUX_COMPLETION_H
   4
   5/*
   6 * (C) Copyright 2001 Linus Torvalds
   7 *
   8 * Atomic wait-for-completion handler data structures.
   9 * See kernel/sched/completion.c for details.
  10 */
  11
  12#include <linux/wait.h>
  13#ifdef CONFIG_LOCKDEP_COMPLETIONS
  14#include <linux/lockdep.h>
  15#endif
  16
  17/*
  18 * struct completion - structure used to maintain state for a "completion"
  19 *
  20 * This is the opaque structure used to maintain the state for a "completion".
  21 * Completions currently use a FIFO to queue threads that have to wait for
  22 * the "completion" event.
  23 *
  24 * See also:  complete(), wait_for_completion() (and friends _timeout,
  25 * _interruptible, _interruptible_timeout, and _killable), init_completion(),
  26 * reinit_completion(), and macros DECLARE_COMPLETION(),
  27 * DECLARE_COMPLETION_ONSTACK().
  28 */
  29struct completion {
  30        unsigned int done;
  31        wait_queue_head_t wait;
  32#ifdef CONFIG_LOCKDEP_COMPLETIONS
  33        struct lockdep_map_cross map;
  34#endif
  35};
  36
  37#ifdef CONFIG_LOCKDEP_COMPLETIONS
  38static inline void complete_acquire(struct completion *x)
  39{
  40        lock_acquire_exclusive((struct lockdep_map *)&x->map, 0, 0, NULL, _RET_IP_);
  41}
  42
  43static inline void complete_release(struct completion *x)
  44{
  45        lock_release((struct lockdep_map *)&x->map, 0, _RET_IP_);
  46}
  47
  48static inline void complete_release_commit(struct completion *x)
  49{
  50        lock_commit_crosslock((struct lockdep_map *)&x->map);
  51}
  52
  53#define init_completion(x)                                              \
  54do {                                                                    \
  55        static struct lock_class_key __key;                             \
  56        lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map,     \
  57                        "(complete)" #x,                                \
  58                        &__key, 0);                                     \
  59        __init_completion(x);                                           \
  60} while (0)
  61#else
  62#define init_completion(x) __init_completion(x)
  63static inline void complete_acquire(struct completion *x) {}
  64static inline void complete_release(struct completion *x) {}
  65static inline void complete_release_commit(struct completion *x) {}
  66#endif
  67
  68#ifdef CONFIG_LOCKDEP_COMPLETIONS
  69#define COMPLETION_INITIALIZER(work) \
  70        { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait), \
  71        STATIC_CROSS_LOCKDEP_MAP_INIT("(complete)" #work, &(work)) }
  72#else
  73#define COMPLETION_INITIALIZER(work) \
  74        { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
  75#endif
  76
  77#define COMPLETION_INITIALIZER_ONSTACK(work) \
  78        (*({ init_completion(&work); &work; }))
  79
  80/**
  81 * DECLARE_COMPLETION - declare and initialize a completion structure
  82 * @work:  identifier for the completion structure
  83 *
  84 * This macro declares and initializes a completion structure. Generally used
  85 * for static declarations. You should use the _ONSTACK variant for automatic
  86 * variables.
  87 */
  88#define DECLARE_COMPLETION(work) \
  89        struct completion work = COMPLETION_INITIALIZER(work)
  90
  91/*
  92 * Lockdep needs to run a non-constant initializer for on-stack
  93 * completions - so we use the _ONSTACK() variant for those that
  94 * are on the kernel stack:
  95 */
  96/**
  97 * DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure
  98 * @work:  identifier for the completion structure
  99 *
 100 * This macro declares and initializes a completion structure on the kernel
 101 * stack.
 102 */
 103#ifdef CONFIG_LOCKDEP
 104# define DECLARE_COMPLETION_ONSTACK(work) \
 105        struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
 106#else
 107# define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
 108#endif
 109
 110/**
 111 * init_completion - Initialize a dynamically allocated completion
 112 * @x:  pointer to completion structure that is to be initialized
 113 *
 114 * This inline function will initialize a dynamically created completion
 115 * structure.
 116 */
 117static inline void __init_completion(struct completion *x)
 118{
 119        x->done = 0;
 120        init_waitqueue_head(&x->wait);
 121}
 122
 123/**
 124 * reinit_completion - reinitialize a completion structure
 125 * @x:  pointer to completion structure that is to be reinitialized
 126 *
 127 * This inline function should be used to reinitialize a completion structure so it can
 128 * be reused. This is especially important after complete_all() is used.
 129 */
 130static inline void reinit_completion(struct completion *x)
 131{
 132        x->done = 0;
 133}
 134
 135extern void wait_for_completion(struct completion *);
 136extern void wait_for_completion_io(struct completion *);
 137extern int wait_for_completion_interruptible(struct completion *x);
 138extern int wait_for_completion_killable(struct completion *x);
 139extern unsigned long wait_for_completion_timeout(struct completion *x,
 140                                                   unsigned long timeout);
 141extern unsigned long wait_for_completion_io_timeout(struct completion *x,
 142                                                    unsigned long timeout);
 143extern long wait_for_completion_interruptible_timeout(
 144        struct completion *x, unsigned long timeout);
 145extern long wait_for_completion_killable_timeout(
 146        struct completion *x, unsigned long timeout);
 147extern bool try_wait_for_completion(struct completion *x);
 148extern bool completion_done(struct completion *x);
 149
 150extern void complete(struct completion *);
 151extern void complete_all(struct completion *);
 152
 153#endif
 154