[PATCH] add sem_is_read/write_locked()

Add sem_is_read/write_locked functions to the read/write semaphores, along the
same lines of the *_is_locked spinlock functions.  The swap token tuning patch
uses sem_is_read_locked; sem_is_write_locked is added for completeness.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/asm-x86_64/rwsem.h b/include/asm-x86_64/rwsem.h
index c002175b6e82..46077e9c1910 100644
--- a/include/asm-x86_64/rwsem.h
+++ b/include/asm-x86_64/rwsem.h
@@ -274,5 +274,10 @@ LOCK_PREFIX	"xaddl %0,(%2)"
         return tmp+delta;
 }
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+        return (sem->count != 0);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _X8664_RWSEM_H */