[PATCH 17/20] mutex: Provide mutex_is_contended

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

[-- Attachment #1: mutex-is-contended.patch --]
[-- Type: text/plain, Size: 675 bytes --]

Usable for lock-breaks and such.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 include/linux/mutex.h |    5 +++++
 1 file changed, 5 insertions(+)

Index: linux-2.6/include/linux/mutex.h
===================================================================
--- linux-2.6.orig/include/linux/mutex.h
+++ linux-2.6/include/linux/mutex.h
@@ -118,6 +118,11 @@ static inline int mutex_is_locked(struct
 	return atomic_read(&lock->count) != 1;
 }
 
+static inline int mutex_is_contended(struct mutex *lock)
+{
+	return atomic_read(&lock->count) < 0;
+}
+
 /*
  * See kernel/mutex.c for detailed documentation of these APIs.
  * Also see Documentation/mutex-design.txt.