[PATCH] drm: Use kref_put_mutex in drm_gem_object_unreference_unlocked

[Maarten Lankhorst]

If kref_put_mutex returns true then the caller or the put function is responsible
for unlocking the mutex.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 1e6ae1458f7a..7a592d7e398b 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -149,14 +149,16 @@ drm_gem_object_unreference(struct drm_gem_object *obj)
 static inline void
 drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
 {
-	if (obj && !atomic_add_unless(&obj->refcount.refcount, -1, 1)) {
-		struct drm_device *dev = obj->dev;
+	struct drm_device *dev;
+
+	if (!obj)
+		return;
 
-		mutex_lock(&dev->struct_mutex);
-		if (likely(atomic_dec_and_test(&obj->refcount.refcount)))
-			drm_gem_object_free(&obj->refcount);
+	dev = obj->dev;
+	if (kref_put_mutex(&obj->refcount, drm_gem_object_free, &dev->struct_mutex))
 		mutex_unlock(&dev->struct_mutex);
-	}
+	else
+		might_lock(&dev->struct_mutex);
 }
 
 int drm_gem_handle_create(struct drm_file *file_priv,