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