patches/simple-wait-rename-and-export-the-equivalent-of-wait.patch

From 069b715a6b4f86a4a09a0be1d7156c7b388eaf2d Mon Sep 17 00:00:00 2001
From: Paul Gortmaker <paul.gortmaker@windriver.com>
Date: Tue, 27 Aug 2013 14:20:26 -0400
Subject: [PATCH] simple-wait: rename and export the equivalent of
 waitqueue_active()

The function "swait_head_has_waiters()" was internalized into
wait-simple.c but it parallels the waitqueue_active of normal
waitqueue support. Given that there are over 150 waitqueue_active
users in drivers/ fs/ kernel/ and the like, lets make it globally
visible, and rename it to parallel the waitqueue_active accordingly.
We'll need to do this if we expect to expand its usage beyond RT.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 include/linux/wait-simple.h |    8 ++++++++
 kernel/wait-simple.c        |   10 +---------
 2 files changed, 9 insertions(+), 9 deletions(-)

--- a/include/linux/wait-simple.h
+++ b/include/linux/wait-simple.h
@@ -47,6 +47,14 @@ extern void swait_prepare(struct swait_h
 extern void swait_finish_locked(struct swait_head *head, struct swaiter *w);
 extern void swait_finish(struct swait_head *head, struct swaiter *w);
 
+/* Check whether a head has waiters enqueued */
+static inline bool swaitqueue_active(struct swait_head *h)
+{
+	/* Make sure the condition is visible before checking list_empty() */
+	smp_mb();
+	return !list_empty(&h->list);
+}
+
 /*
  * Wakeup functions
  */
--- a/kernel/wait-simple.c
+++ b/kernel/wait-simple.c
@@ -26,14 +26,6 @@ static inline void __swait_dequeue(struc
 	list_del_init(&w->node);
 }
 
-/* Check whether a head has waiters enqueued */
-static inline bool swait_head_has_waiters(struct swait_head *h)
-{
-	/* Make sure the condition is visible before checking list_empty() */
-	smp_mb();
-	return !list_empty(&h->list);
-}
-
 void __init_swait_head(struct swait_head *head, struct lock_class_key *key)
 {
 	raw_spin_lock_init(&head->lock);
@@ -112,7 +104,7 @@ __swait_wake(struct swait_head *head, un
 	unsigned long flags;
 	int woken;
 
-	if (!swait_head_has_waiters(head))
+	if (!swaitqueue_active(head))
 		return 0;
 
 	raw_spin_lock_irqsave(&head->lock, flags);