include/linux/completion.h

   1 #ifndef __LINUX_COMPLETION_H
   2 #define __LINUX_COMPLETION_H
   3
   4 /*
   5  * (C) Copyright 2001 Linus Torvalds
   6  *
   7  * Atomic wait-for-completion handler data structures.
   8  * See kernel/sched/completion.c for details.
   9  */
  10
  11 #include <linux/wait.h>
  12 #ifdef CONFIG_LOCKDEP_COMPLETIONS
  13 #include <linux/lockdep.h>
  14 #endif
  15
  16 /*
  17  * struct completion - structure used to maintain state for a "completion"
  18  *
  19  * This is the opaque structure used to maintain the state for a "completion".
  20  * Completions currently use a FIFO to queue threads that have to wait for
  21  * the "completion" event.
  22  *
  23  * See also:  complete(), wait_for_completion() (and friends _timeout,
  24  * _interruptible, _interruptible_timeout, and _killable), init_completion(),
  25  * reinit_completion(), and macros DECLARE_COMPLETION(),
  26  * DECLARE_COMPLETION_ONSTACK().
  27  */
  28 struct completion {
  29         unsigned int done;
  30         wait_queue_head_t wait;
  31 #ifdef CONFIG_LOCKDEP_COMPLETIONS
  32         struct lockdep_map_cross map;
  33 #endif
  34 };
  35
  36 #ifdef CONFIG_LOCKDEP_COMPLETIONS
  37 static inline void complete_acquire(struct completion *x)
  38 {
  39         lock_acquire_exclusive((struct lockdep_map *)&x->map, 0, 0, NULL, _RET_IP_);
  40 }
  41
  42 static inline void complete_release(struct completion *x)
  43 {
  44         lock_release((struct lockdep_map *)&x->map, 0, _RET_IP_);
  45 }
  46
  47 static inline void complete_release_commit(struct completion *x)
  48 {
  49         lock_commit_crosslock((struct lockdep_map *)&x->map);
  50 }
  51
  52 #define init_completion(x)                                              \
  53 do {                                                                    \
  54         static struct lock_class_key __key;                             \
  55         lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map,     \
  56                         "(complete)" #x,                                \
  57                         &__key, 0);                                     \
  58         __init_completion(x);                                           \
  59 } while (0)
  60 #else
  61 #define init_completion(x) __init_completion(x)
  62 static inline void complete_acquire(struct completion *x) {}
  63 static inline void complete_release(struct completion *x) {}
  64 static inline void complete_release_commit(struct completion *x) {}
  65 #endif
  66
  67 #ifdef CONFIG_LOCKDEP_COMPLETIONS
  68 #define COMPLETION_INITIALIZER(work) \
  69         { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait), \
  70         STATIC_CROSS_LOCKDEP_MAP_INIT("(complete)" #work, &(work)) }
  71 #else
  72 #define COMPLETION_INITIALIZER(work) \
  73         { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
  74 #endif
  75
  76 #define COMPLETION_INITIALIZER_ONSTACK(work) \
  77         (*({ init_completion(&work); &work; }))
  78
  79 /**
  80  * DECLARE_COMPLETION - declare and initialize a completion structure
  81  * @work:  identifier for the completion structure
  82  *
  83  * This macro declares and initializes a completion structure. Generally used
  84  * for static declarations. You should use the _ONSTACK variant for automatic
  85  * variables.
  86  */
  87 #define DECLARE_COMPLETION(work) \
  88         struct completion work = COMPLETION_INITIALIZER(work)
  89
  90 /*
  91  * Lockdep needs to run a non-constant initializer for on-stack
  92  * completions - so we use the _ONSTACK() variant for those that
  93  * are on the kernel stack:
  94  */
  95 /**
  96  * DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure
  97  * @work:  identifier for the completion structure
  98  *
  99  * This macro declares and initializes a completion structure on the kernel
 100  * stack.
 101  */
 102 #ifdef CONFIG_LOCKDEP
 103 # define DECLARE_COMPLETION_ONSTACK(work) \
 104         struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
 105 #else
 106 # define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
 107 #endif
 108
 109 /**
 110  * init_completion - Initialize a dynamically allocated completion
 111  * @x:  pointer to completion structure that is to be initialized
 112  *
 113  * This inline function will initialize a dynamically created completion
 114  * structure.
 115  */
 116 static inline void __init_completion(struct completion *x)
 117 {
 118         x->done = 0;
 119         init_waitqueue_head(&x->wait);
 120 }
 121
 122 /**
 123  * reinit_completion - reinitialize a completion structure
 124  * @x:  pointer to completion structure that is to be reinitialized
 125  *
 126  * This inline function should be used to reinitialize a completion structure so it can
 127  * be reused. This is especially important after complete_all() is used.
 128  */
 129 static inline void reinit_completion(struct completion *x)
 130 {
 131         x->done = 0;
 132 }
 133
 134 extern void wait_for_completion(struct completion *);
 135 extern void wait_for_completion_io(struct completion *);
 136 extern int wait_for_completion_interruptible(struct completion *x);
 137 extern int wait_for_completion_killable(struct completion *x);
 138 extern unsigned long wait_for_completion_timeout(struct completion *x,
 139                                                    unsigned long timeout);
 140 extern unsigned long wait_for_completion_io_timeout(struct completion *x,
 141                                                     unsigned long timeout);
 142 extern long wait_for_completion_interruptible_timeout(
 143         struct completion *x, unsigned long timeout);
 144 extern long wait_for_completion_killable_timeout(
 145         struct completion *x, unsigned long timeout);
 146 extern bool try_wait_for_completion(struct completion *x);
 147 extern bool completion_done(struct completion *x);
 148
 149 extern void complete(struct completion *);
 150 extern void complete_all(struct completion *);
 151
 152 #endif