kref: add kref_test_and_get

[mv-sheeva.git] / lib / kref.c

diff --git a/lib/kref.c b/lib/kref.c
index d3d227a08a4bdb79cae0b2f21be905451c607719..e7a6e106712231ba43b0aa426bcfd003ce8409a7 100644 (file)
--- a/lib/kref.c
+++ b/lib/kref.c
@@ -36,6 +36,18 @@ void kref_get(struct kref *kref)
        smp_mb__after_atomic_inc();
 }
 
+/**
+ * kref_test_and_get - increment refcount for object only if refcount is not
+ * zero.
+ * @kref: object.
+ *
+ * Return non-zero if the refcount was incremented, 0 otherwise
+ */
+int kref_test_and_get(struct kref *kref)
+{
+       return atomic_inc_not_zero(&kref->refcount);
+}
+
 /**
  * kref_put - decrement refcount for object.
  * @kref: object.