Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-block.git] / include / linux / wait.h

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 4707543ef5752a6bd321fde91b9be49eaef4a856..3eb7cae8206c38d153ecdb72f0c7666b4fec42b7 100644 (file)
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -126,6 +126,19 @@ static inline int waitqueue_active(struct wait_queue_head *wq_head)
        return !list_empty(&wq_head->head);
 }
 
+/**
+ * wq_has_single_sleeper - check if there is only one sleeper
+ * @wq_head: wait queue head
+ *
+ * Returns true of wq_head has only one sleeper on the list.
+ *
+ * Please refer to the comment for waitqueue_active.
+ */
+static inline bool wq_has_single_sleeper(struct wait_queue_head *wq_head)
+{
+       return list_is_singular(&wq_head->head);
+}
+
 /**
  * wq_has_sleeper - check if there are any waiting processes
  * @wq_head: wait queue head