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 */
29 struct 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
complete_acquire(struct completion * x)38 static inline void complete_acquire(struct completion *x)
39 {
40 lock_acquire_exclusive((struct lockdep_map *)&x->map, 0, 0, NULL, _RET_IP_);
41 }
42
complete_release(struct completion * x)43 static inline void complete_release(struct completion *x)
44 {
45 lock_release((struct lockdep_map *)&x->map, 0, _RET_IP_);
46 }
47
complete_release_commit(struct completion * x)48 static 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) \
54 do { \
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)
complete_acquire(struct completion * x)63 static inline void complete_acquire(struct completion *x) {}
complete_release(struct completion * x)64 static inline void complete_release(struct completion *x) {}
complete_release_commit(struct completion * x)65 static 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 */
__init_completion(struct completion * x)117 static 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 */
reinit_completion(struct completion * x)130 static inline void reinit_completion(struct completion *x)
131 {
132 x->done = 0;
133 }
134
135 extern void wait_for_completion(struct completion *);
136 extern void wait_for_completion_io(struct completion *);
137 extern int wait_for_completion_interruptible(struct completion *x);
138 extern int wait_for_completion_killable(struct completion *x);
139 extern unsigned long wait_for_completion_timeout(struct completion *x,
140 unsigned long timeout);
141 extern unsigned long wait_for_completion_io_timeout(struct completion *x,
142 unsigned long timeout);
143 extern long wait_for_completion_interruptible_timeout(
144 struct completion *x, unsigned long timeout);
145 extern long wait_for_completion_killable_timeout(
146 struct completion *x, unsigned long timeout);
147 extern bool try_wait_for_completion(struct completion *x);
148 extern bool completion_done(struct completion *x);
149
150 extern void complete(struct completion *);
151 extern void complete_all(struct completion *);
152
153 #endif
154