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  */
  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
  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
  43 static inline void complete_release(struct completion *x)
  44 {
  45         lock_release((struct lockdep_map *)&x->map, 0, _RET_IP_);
  46 }
  47
  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_map(x, m)                                       \
  54 do {                                                                    \
  55         lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map,     \
  56                         (m)->name, (m)->key, 0);                                \
  57         __init_completion(x);                                           \
  58 } while (0)
  59
  60 #define init_completion(x)                                              \
  61 do {                                                                    \
  62         static struct lock_class_key __key;                             \
  63         lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map,     \
  64                         "(completion)" #x,                              \
  65                         &__key, 0);                                     \
  66         __init_completion(x);                                           \
  67 } while (0)
  68 #else
  69 #define init_completion_map(x, m) __init_completion(x)
  70 #define init_completion(x) __init_completion(x)
  71 static inline void complete_acquire(struct completion *x) {}
  72 static inline void complete_release(struct completion *x) {}
  73 static inline void complete_release_commit(struct completion *x) {}
  74 #endif
  75
  76 #ifdef CONFIG_LOCKDEP_COMPLETIONS
  77 #define COMPLETION_INITIALIZER(work) \
  78         { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait), \
  79         STATIC_CROSS_LOCKDEP_MAP_INIT("(completion)" #work, &(work)) }
  80 #else
  81 #define COMPLETION_INITIALIZER(work) \
  82         { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
  83 #endif
  84
  85 #define COMPLETION_INITIALIZER_ONSTACK_MAP(work, map) \
  86         (*({ init_completion_map(&(work), &(map)); &(work); }))
  87
  88 #define COMPLETION_INITIALIZER_ONSTACK(work) \
  89         (*({ init_completion(&work); &work; }))
  90
  91 /**
  92  * DECLARE_COMPLETION - declare and initialize a completion structure
  93  * @work:  identifier for the completion structure
  94  *
  95  * This macro declares and initializes a completion structure. Generally used
  96  * for static declarations. You should use the _ONSTACK variant for automatic
  97  * variables.
  98  */
  99 #define DECLARE_COMPLETION(work) \
 100         struct completion work = COMPLETION_INITIALIZER(work)
 101
 102 /*
 103  * Lockdep needs to run a non-constant initializer for on-stack
 104  * completions - so we use the _ONSTACK() variant for those that
 105  * are on the kernel stack:
 106  */
 107 /**
 108  * DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure
 109  * @work:  identifier for the completion structure
 110  *
 111  * This macro declares and initializes a completion structure on the kernel
 112  * stack.
 113  */
 114 #ifdef CONFIG_LOCKDEP
 115 # define DECLARE_COMPLETION_ONSTACK(work) \
 116         struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
 117 # define DECLARE_COMPLETION_ONSTACK_MAP(work, map) \
 118         struct completion work = COMPLETION_INITIALIZER_ONSTACK_MAP(work, map)
 119 #else
 120 # define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
 121 # define DECLARE_COMPLETION_ONSTACK_MAP(work, map) DECLARE_COMPLETION(work)
 122 #endif
 123
 124 /**
 125  * init_completion - Initialize a dynamically allocated completion
 126  * @x:  pointer to completion structure that is to be initialized
 127  *
 128  * This inline function will initialize a dynamically created completion
 129  * structure.
 130  */
 131 static inline void __init_completion(struct completion *x)
 132 {
 133         x->done = 0;
 134         init_waitqueue_head(&x->wait);
 135 }
 136
 137 /**
 138  * reinit_completion - reinitialize a completion structure
 139  * @x:  pointer to completion structure that is to be reinitialized
 140  *
 141  * This inline function should be used to reinitialize a completion structure so it can
 142  * be reused. This is especially important after complete_all() is used.
 143  */
 144 static inline void reinit_completion(struct completion *x)
 145 {
 146         x->done = 0;
 147 }
 148
 149 extern void wait_for_completion(struct completion *);
 150 extern void wait_for_completion_io(struct completion *);
 151 extern int wait_for_completion_interruptible(struct completion *x);
 152 extern int wait_for_completion_killable(struct completion *x);
 153 extern unsigned long wait_for_completion_timeout(struct completion *x,
 154                                                    unsigned long timeout);
 155 extern unsigned long wait_for_completion_io_timeout(struct completion *x,
 156                                                     unsigned long timeout);
 157 extern long wait_for_completion_interruptible_timeout(
 158         struct completion *x, unsigned long timeout);
 159 extern long wait_for_completion_killable_timeout(
 160         struct completion *x, unsigned long timeout);
 161 extern bool try_wait_for_completion(struct completion *x);
 162 extern bool completion_done(struct completion *x);
 163
 164 extern void complete(struct completion *);
 165 extern void complete_all(struct completion *);
 166
 167 #endif