sched/wake_q: Reduce reference counting for special users

[linux.git] / include / linux / sched / wake_q.h

diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h
index 10b19a192b2d000121eff7dc91e8f224918d5fec..ad826d2a4557dea643c18e2c160c6d1f48650431 100644 (file)
--- a/include/linux/sched/wake_q.h
+++ b/include/linux/sched/wake_q.h
@@ -24,9 +24,13 @@
  * called near the end of a function. Otherwise, the list can be
  * re-initialized for later re-use by wake_q_init().
  *
- * Note that this can cause spurious wakeups. schedule() callers
+ * NOTE that this can cause spurious wakeups. schedule() callers
  * must ensure the call is done inside a loop, confirming that the
  * wakeup condition has in fact occurred.
+ *
+ * NOTE that there is no guarantee the wakeup will happen any later than the
+ * wake_q_add() location. Therefore task must be ready to be woken at the
+ * location of the wake_q_add().
  */
 
 #include <linux/sched.h>
@@ -47,8 +51,8 @@ static inline void wake_q_init(struct wake_q_head *head)
        head->lastp = &head->first;
 }
 
-extern void wake_q_add(struct wake_q_head *head,
-                      struct task_struct *task);
+extern void wake_q_add(struct wake_q_head *head, struct task_struct *task);
+extern void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task);
 extern void wake_up_q(struct wake_q_head *head);
 
 #endif /* _LINUX_SCHED_WAKE_Q_H */