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)
32 #define init_completion(x) __init_completion(x)
complete_acquire(struct completion * x)33 static inline void complete_acquire(struct completion *x) {}
complete_release(struct completion * x)34 static inline void complete_release(struct completion *x) {}
35
36 #define COMPLETION_INITIALIZER(work) \
37 { 0, __SWAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
38
39 #define COMPLETION_INITIALIZER_ONSTACK_MAP(work, map) \
40 (*({ init_completion_map(&(work), &(map)); &(work); }))
41
42 #define COMPLETION_INITIALIZER_ONSTACK(work) \
43 (*({ init_completion(&work); &work; }))
44
45 /**
46 * DECLARE_COMPLETION - declare and initialize a completion structure
47 * @work: identifier for the completion structure
48 *
49 * This macro declares and initializes a completion structure. Generally used
50 * for static declarations. You should use the _ONSTACK variant for automatic
51 * variables.
52 */
53 #define DECLARE_COMPLETION(work) \
54 struct completion work = COMPLETION_INITIALIZER(work)
55
56 /*
57 * Lockdep needs to run a non-constant initializer for on-stack
58 * completions - so we use the _ONSTACK() variant for those that
59 * are on the kernel stack:
60 */
61 /**
62 * DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure
63 * @work: identifier for the completion structure
64 *
65 * This macro declares and initializes a completion structure on the kernel
66 * stack.
67 */
68 #ifdef CONFIG_LOCKDEP
69 # define DECLARE_COMPLETION_ONSTACK(work) \
70 struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
71 # define DECLARE_COMPLETION_ONSTACK_MAP(work, map) \
72 struct completion work = COMPLETION_INITIALIZER_ONSTACK_MAP(work, map)
73 #else
74 # define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
75 # define DECLARE_COMPLETION_ONSTACK_MAP(work, map) DECLARE_COMPLETION(work)
76 #endif
77
78 /**
79 * init_completion - Initialize a dynamically allocated completion
80 * @x: pointer to completion structure that is to be initialized
81 *
82 * This inline function will initialize a dynamically created completion
83 * structure.
84 */
__init_completion(struct completion * x)85 static inline void __init_completion(struct completion *x)
86 {
87 x->done = 0;
88 init_swait_queue_head(&x->wait);
89 }
90
91 /**
92 * reinit_completion - reinitialize a completion structure
93 * @x: pointer to completion structure that is to be reinitialized
94 *
95 * This inline function should be used to reinitialize a completion structure so it can
96 * be reused. This is especially important after complete_all() is used.
97 */
reinit_completion(struct completion * x)98 static inline void reinit_completion(struct completion *x)
99 {
100 x->done = 0;
101 }
102
103 extern void wait_for_completion(struct completion *);
104 extern void wait_for_completion_io(struct completion *);
105 extern int wait_for_completion_interruptible(struct completion *x);
106 extern int wait_for_completion_killable(struct completion *x);
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_all(struct completion *);
120
121 #endif
122
