diff options
Diffstat (limited to 'include/linux/wait_bit.h')
| -rw-r--r-- | include/linux/wait_bit.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/wait_bit.h b/include/linux/wait_bit.h index 553d7b23e3ad..af077ed4caf6 100644 --- a/include/linux/wait_bit.h +++ b/include/linux/wait_bit.h @@ -433,6 +433,32 @@ do { \ }) /** + * wait_var_event_state - wait for a variable to be updated and notified + * @var: the address of variable being waited on + * @condition: the condition to wait for + * @state: the task state to sleep in, %TASK_UNINTERRUPTIBLE etc. + * + * Wait for a @condition to be true, only re-checking when a wake up is + * received for the given @var (an arbitrary kernel address which need + * not be directly related to the given condition, but usually is). + * + * Returns 0 if the condition became true, or %-ERESTARTSYS if a signal + * arrived which @state allows to interrupt. + * + * The condition should normally use smp_load_acquire() or a similarly + * ordered access to ensure that any changes to memory made before the + * condition became true will be visible after the wait completes. + */ +#define wait_var_event_state(var, condition, state) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = ___wait_var_event(var, condition, (state), 0, 0, schedule()); \ + __ret; \ +}) + +/** * wait_var_event_any_lock - wait for a variable to be updated under a lock * @var: the address of the variable being waited on * @condition: condition to wait for |