xref: /linux/include/linux/completion.h (revision a1c613ae4c322ddd58d5a8539dbfba2a0380a8c0)
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  */
26 struct completion {
27 	unsigned int done;
28 	struct swait_queue_head wait;
29 };
30 
31 #define init_completion_map(x, m) init_completion(x)
complete_acquire(struct completion * x)32 static inline void complete_acquire(struct completion *x) {}
complete_release(struct completion * x)33 static 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  */
init_completion(struct completion * x)84 static 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  */
reinit_completion(struct completion * x)97 static inline void reinit_completion(struct completion *x)
98 {
99 	x->done = 0;
100 }
101 
102 extern void wait_for_completion(struct completion *);
103 extern void wait_for_completion_io(struct completion *);
104 extern int wait_for_completion_interruptible(struct completion *x);
105 extern int wait_for_completion_killable(struct completion *x);
106 extern int wait_for_completion_state(struct completion *x, unsigned int state);
107 extern unsigned long wait_for_completion_timeout(struct completion *x,
108 						   unsigned long timeout);
109 extern unsigned long wait_for_completion_io_timeout(struct completion *x,
110 						    unsigned long timeout);
111 extern long wait_for_completion_interruptible_timeout(
112 	struct completion *x, unsigned long timeout);
113 extern long wait_for_completion_killable_timeout(
114 	struct completion *x, unsigned long timeout);
115 extern bool try_wait_for_completion(struct completion *x);
116 extern bool completion_done(struct completion *x);
117 
118 extern void complete(struct completion *);
119 extern void complete_on_current_cpu(struct completion *x);
120 extern void complete_all(struct completion *);
121 
122 #endif
123