[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,