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/swait.h>
13
14/*
15 * struct completion - structure used to maintain state for a "completion"
16 *
17 * This is the opaque structure used to maintain the state for a "completion".
18 * Completions currently use a FIFO to queue threads that have to wait for
19 * the "completion" event.
20 *
21 * See also: complete(), wait_for_completion() (and friends _timeout,
22 * _interruptible, _interruptible_timeout, and _killable), init_completion(),
23 * reinit_completion(), and macros DECLARE_COMPLETION(),
24 * DECLARE_COMPLETION_ONSTACK().
25 */
26struct completion {
27 unsigned int done;
28 struct swait_queue_head wait;
29};
30
31#define init_completion_map(x, m) init_completion(x)
32static inline void complete_acquire(struct completion *x) {}
33static inline void complete_release(struct completion *x) {}
34
35#define COMPLETION_INITIALIZER(work) \
36 { 0, __SWAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
37
38#define COMPLETION_INITIALIZER_ONSTACK_MAP(work, map) \
39 (*({ init_completion_map(&(work), &(map)); &(work); }))
40
41#define COMPLETION_INITIALIZER_ONSTACK(work) \
42 (*({ init_completion(&work); &work; }))
43
44/**
45 * DECLARE_COMPLETION - declare and initialize a completion structure
46 * @work: identifier for the completion structure
47 *
48 * This macro declares and initializes a completion structure. Generally used
49 * for static declarations. You should use the _ONSTACK variant for automatic
50 * variables.
51 */
52#define DECLARE_COMPLETION(work) \
53 struct completion work = COMPLETION_INITIALIZER(work)
54
55/*
56 * Lockdep needs to run a non-constant initializer for on-stack
57 * completions - so we use the _ONSTACK() variant for those that
58 * are on the kernel stack:
59 */
60/**
61 * DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure
62 * @work: identifier for the completion structure
63 *
64 * This macro declares and initializes a completion structure on the kernel
65 * stack.
66 */
67#ifdef CONFIG_LOCKDEP
68# define DECLARE_COMPLETION_ONSTACK(work) \
69 struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
70# define DECLARE_COMPLETION_ONSTACK_MAP(work, map) \
71 struct completion work = COMPLETION_INITIALIZER_ONSTACK_MAP(work, map)
72#else
73# define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
74# define DECLARE_COMPLETION_ONSTACK_MAP(work, map) DECLARE_COMPLETION(work)
75#endif
76
77/**
78 * init_completion - Initialize a dynamically allocated completion
79 * @x: pointer to completion structure that is to be initialized
80 *
81 * This inline function will initialize a dynamically created completion
82 * structure.
83 */
84static inline void init_completion(struct completion *x)
85{
86 x->done = 0;
87 init_swait_queue_head(&x->wait);
88}
89
90/**
91 * reinit_completion - reinitialize a completion structure
92 * @x: pointer to completion structure that is to be reinitialized
93 *
94 * This inline function should be used to reinitialize a completion structure so it can
95 * be reused. This is especially important after complete_all() is used.
96 */
97static inline void reinit_completion(struct completion *x)
98{
99 x->done = 0;
100}
101
102extern void wait_for_completion(struct completion *);
103extern void wait_for_completion_io(struct completion *);
104extern int wait_for_completion_interruptible(struct completion *x);
105extern int wait_for_completion_killable(struct completion *x);
106extern unsigned long wait_for_completion_timeout(struct completion *x,
107 unsigned long timeout);
108extern unsigned long wait_for_completion_io_timeout(struct completion *x,
109 unsigned long timeout);
110extern long wait_for_completion_interruptible_timeout(
111 struct completion *x, unsigned long timeout);
112extern long wait_for_completion_killable_timeout(
113 struct completion *x, unsigned long timeout);
114extern bool try_wait_for_completion(struct completion *x);
115extern bool completion_done(struct completion *x);
116
117extern void complete(struct completion *);
118extern void complete_all(struct completion *);
119
120#endif
121

source code of linux/include/linux/completion.h