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
  36 #define COMPLETION_INITIALIZER(work) \
  37         { 0, __WAIT_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  */
  85 static inline void __init_completion(struct completion *x)
  86 {
  87         x->done = 0;
  88         init_waitqueue_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  */
  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