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