diff options
Diffstat (limited to 'include/linux/completion.h')
| -rw-r--r-- | include/linux/completion.h | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/include/linux/completion.h b/include/linux/completion.h index d2961b66d53d..57faa60de9bd 100644 --- a/include/linux/completion.h +++ b/include/linux/completion.h @@ -55,4 +55,49 @@ extern void complete_all(struct completion *); #define INIT_COMPLETION(x) ((x).done = 0) + +/** + * try_wait_for_completion - try to decrement a completion without blocking + * @x: completion structure + * + * Returns: 0 if a decrement cannot be done without blocking + * 1 if a decrement succeeded. + * + * If a completion is being used as a counting completion, + * attempt to decrement the counter without blocking. This + * enables us to avoid waiting if the resource the completion + * is protecting is not available. + */ +static inline bool try_wait_for_completion(struct completion *x) +{ + int ret = 1; + + spin_lock_irq(&x->wait.lock); + if (!x->done) + ret = 0; + else + x->done--; + spin_unlock_irq(&x->wait.lock); + return ret; +} + +/** + * completion_done - Test to see if a completion has any waiters + * @x: completion structure + * + * Returns: 0 if there are waiters (wait_for_completion() in progress) + * 1 if there are no waiters. + * + */ +static inline bool completion_done(struct completion *x) +{ + int ret = 1; + + spin_lock_irq(&x->wait.lock); + if (!x->done) + ret = 0; + spin_unlock_irq(&x->wait.lock); + return ret; +} + #endif |