3 files changed, 80 insertions, 37 deletions

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 25dac31eef37..973eb8805ce0 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -806,12 +806,64 @@ drm_gem_object_free(struct kref *kref)
 
 	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 
-	if (dev->driver->gem_free_object != NULL)
+	if (dev->driver->gem_free_object_unlocked)
+		dev->driver->gem_free_object_unlocked(obj);
+	else if (dev->driver->gem_free_object)
 		dev->driver->gem_free_object(obj);
 }
 EXPORT_SYMBOL(drm_gem_object_free);
 
 /**
+ * drm_gem_object_unreference_unlocked - release a GEM BO reference
+ * @obj: GEM buffer object
+ *
+ * This releases a reference to @obj. Callers must not hold the
+ * dev->struct_mutex lock when calling this function.
+ *
+ * See also __drm_gem_object_unreference().
+ */
+void
+drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
+{
+	struct drm_device *dev;
+
+	if (!obj)
+		return;
+
+	dev = obj->dev;
+	might_lock(&dev->struct_mutex);
+
+	if (dev->driver->gem_free_object_unlocked)
+		kref_put(&obj->refcount, drm_gem_object_free);
+	else if (kref_put_mutex(&obj->refcount, drm_gem_object_free,
+				&dev->struct_mutex))
+		mutex_unlock(&dev->struct_mutex);
+}
+EXPORT_SYMBOL(drm_gem_object_unreference_unlocked);
+
+/**
+ * drm_gem_object_unreference - release a GEM BO reference
+ * @obj: GEM buffer object
+ *
+ * This releases a reference to @obj. Callers must hold the dev->struct_mutex
+ * lock when calling this function, even when the driver doesn't use
+ * dev->struct_mutex for anything.
+ *
+ * For drivers not encumbered with legacy locking use
+ * drm_gem_object_unreference_unlocked() instead.
+ */
+void
+drm_gem_object_unreference(struct drm_gem_object *obj)
+{
+	if (obj) {
+		WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
+
+		kref_put(&obj->refcount, drm_gem_object_free);
+	}
+}
+EXPORT_SYMBOL(drm_gem_object_unreference);
+
+/**
  * drm_gem_vm_open - vma->ops->open implementation for GEM
  * @vma: VM area structure
  *
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 7901768bb47c..360b2a74e1ef 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -580,12 +580,21 @@ struct drm_driver {
 	void (*debugfs_cleanup)(struct drm_minor *minor);
 
 	/**
-	 * Driver-specific constructor for drm_gem_objects, to set up
-	 * obj->driver_private.
+	 * @gem_free_object: deconstructor for drm_gem_objects
 	 *
-	 * Returns 0 on success.
+	 * This is deprecated and should not be used by new drivers. Use
+	 * @gem_free_object_unlocked instead.
 	 */
 	void (*gem_free_object) (struct drm_gem_object *obj);
+
+	/**
+	 * @gem_free_object_unlocked: deconstructor for drm_gem_objects
+	 *
+	 * This is for drivers which are not encumbered with dev->struct_mutex
+	 * legacy locking schemes. Use this hook instead of @gem_free_object.
+	 */
+	void (*gem_free_object_unlocked) (struct drm_gem_object *obj);
+
 	int (*gem_open_object) (struct drm_gem_object *, struct drm_file *);
 	void (*gem_close_object) (struct drm_gem_object *, struct drm_file *);
 
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 0b3e11ab8757..408d6c47d98b 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -200,47 +200,29 @@ drm_gem_object_reference(struct drm_gem_object *obj)
 }
 
 /**
- * drm_gem_object_unreference - release a GEM BO reference
+ * __drm_gem_object_unreference - raw function to release a GEM BO reference
  * @obj: GEM buffer object
  *
- * This releases a reference to @obj. Callers must hold the dev->struct_mutex
- * lock when calling this function, even when the driver doesn't use
- * dev->struct_mutex for anything.
+ * This function is meant to be used by drivers which are not encumbered with
+ * dev->struct_mutex legacy locking and which are using the
+ * gem_free_object_unlocked callback. It avoids all the locking checks and
+ * locking overhead of drm_gem_object_unreference() and
+ * drm_gem_object_unreference_unlocked().
  *
- * For drivers not encumbered with legacy locking use
- * drm_gem_object_unreference_unlocked() instead.
+ * Drivers should never call this directly in their code. Instead they should
+ * wrap it up into a driver_gem_object_unreference(struct driver_gem_object
+ * *obj) wrapper function, and use that. Shared code should never call this, to
+ * avoid breaking drivers by accident which still depend upon dev->struct_mutex
+ * locking.
  */
 static inline void
-drm_gem_object_unreference(struct drm_gem_object *obj)
+__drm_gem_object_unreference(struct drm_gem_object *obj)
 {
-	if (obj != NULL) {
-		WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
-
-		kref_put(&obj->refcount, drm_gem_object_free);
-	}
+	kref_put(&obj->refcount, drm_gem_object_free);
 }
 
-/**
- * drm_gem_object_unreference_unlocked - release a GEM BO reference
- * @obj: GEM buffer object
- *
- * This releases a reference to @obj. Callers must not hold the
- * dev->struct_mutex lock when calling this function.
- */
-static inline void
-drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
-{
-	struct drm_device *dev;
-
-	if (!obj)
-		return;
-
-	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);
-}
+void drm_gem_object_unreference_unlocked(struct drm_gem_object *obj);
+void drm_gem_object_unreference(struct drm_gem_object *obj);
 
 int drm_gem_handle_create(struct drm_file *file_priv,
 			  struct drm_gem_object *obj,