diff options
Diffstat (limited to 'include/linux/rcuwait.h')
| -rw-r--r-- | include/linux/rcuwait.h | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h index 2ffe1ee6d482..61c56cca95c4 100644 --- a/include/linux/rcuwait.h +++ b/include/linux/rcuwait.h @@ -25,16 +25,38 @@ static inline void rcuwait_init(struct rcuwait *w) w->task = NULL; } -extern void rcuwait_wake_up(struct rcuwait *w); +/* + * Note: this provides no serialization and, just as with waitqueues, + * requires care to estimate as to whether or not the wait is active. + */ +static inline int rcuwait_active(struct rcuwait *w) +{ + return !!rcu_access_pointer(w->task); +} + +extern int rcuwait_wake_up(struct rcuwait *w); /* * The caller is responsible for locking around rcuwait_wait_event(), - * such that writes to @task are properly serialized. + * and [prepare_to/finish]_rcuwait() such that writes to @task are + * properly serialized. */ + +static inline void prepare_to_rcuwait(struct rcuwait *w) +{ + rcu_assign_pointer(w->task, current); +} + +static inline void finish_rcuwait(struct rcuwait *w) +{ + rcu_assign_pointer(w->task, NULL); + __set_current_state(TASK_RUNNING); +} + #define rcuwait_wait_event(w, condition, state) \ ({ \ int __ret = 0; \ - rcu_assign_pointer((w)->task, current); \ + prepare_to_rcuwait(w); \ for (;;) { \ /* \ * Implicit barrier (A) pairs with (B) in \ @@ -51,9 +73,7 @@ extern void rcuwait_wake_up(struct rcuwait *w); \ schedule(); \ } \ - \ - WRITE_ONCE((w)->task, NULL); \ - __set_current_state(TASK_RUNNING); \ + finish_rcuwait(w); \ __ret; \ }) |