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