drm: Introduce drm_gem_object_{get,put}()

For consistency with other reference counting APIs in the kernel, add
drm_gem_object_get() and drm_gem_object_put(), as well as an unlocked
variant of the latter, to reference count GEM buffer objects.

Compatibility aliases are added to keep existing code working. To help
speed up the transition, all the instances of the old functions in the
DRM core are already replaced in this commit.

The existing semantic patch for the DRM subsystem-wide conversion is
extended to account for these new helpers.

Reviewed-by: Sean Paul <seanpaul@chromium.org>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170228144643.5668-6-thierry.reding@gmail.com

1 files changed, 64 insertions, 16 deletions

diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 449a41b56ffc..3b2a28f7f49f 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -48,9 +48,9 @@ struct drm_gem_object {
 	 *
 	 * Reference count of this object
 	 *
-	 * Please use drm_gem_object_reference() to acquire and
-	 * drm_gem_object_unreference() or drm_gem_object_unreference_unlocked()
-	 * to release a reference to a GEM buffer object.
+	 * Please use drm_gem_object_get() to acquire and drm_gem_object_put()
+	 * or drm_gem_object_put_unlocked() to release a reference to a GEM
+	 * buffer object.
 	 */
 	struct kref refcount;
 
@@ -187,42 +187,90 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma);
 
 /**
- * drm_gem_object_reference - acquire a GEM BO reference
+ * drm_gem_object_get - acquire a GEM buffer object reference
  * @obj: GEM buffer object
  *
- * This acquires additional reference to @obj. It is illegal to call this
- * without already holding a reference. No locks required.
+ * This function acquires an additional reference to @obj. It is illegal to
+ * call this without already holding a reference. No locks required.
  */
-static inline void
-drm_gem_object_reference(struct drm_gem_object *obj)
+static inline void drm_gem_object_get(struct drm_gem_object *obj)
 {
 	kref_get(&obj->refcount);
 }
 
 /**
- * __drm_gem_object_unreference - raw function to release a GEM BO reference
+ * __drm_gem_object_put - raw function to release a GEM buffer object reference
  * @obj: GEM buffer object
  *
  * This function is meant to be used by drivers which are not encumbered with
  * &drm_device.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().
+ * locking overhead of drm_gem_object_put() and drm_gem_object_put_unlocked().
  *
  * 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
+ * wrap it up into a ``driver_gem_object_put(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
  * &drm_device.struct_mutex locking.
  */
 static inline void
-__drm_gem_object_unreference(struct drm_gem_object *obj)
+__drm_gem_object_put(struct drm_gem_object *obj)
 {
 	kref_put(&obj->refcount, drm_gem_object_free);
 }
 
-void drm_gem_object_unreference_unlocked(struct drm_gem_object *obj);
-void drm_gem_object_unreference(struct drm_gem_object *obj);
+void drm_gem_object_put_unlocked(struct drm_gem_object *obj);
+void drm_gem_object_put(struct drm_gem_object *obj);
+
+/**
+ * drm_gem_object_reference - acquire a GEM buffer object reference
+ * @obj: GEM buffer object
+ *
+ * This is a compatibility alias for drm_gem_object_get() and should not be
+ * used by new code.
+ */
+static inline void drm_gem_object_reference(struct drm_gem_object *obj)
+{
+	drm_gem_object_get(obj);
+}
+
+/**
+ * __drm_gem_object_unreference - raw function to release a GEM buffer object
+ *                                reference
+ * @obj: GEM buffer object
+ *
+ * This is a compatibility alias for __drm_gem_object_put() and should not be
+ * used by new code.
+ */
+static inline void __drm_gem_object_unreference(struct drm_gem_object *obj)
+{
+	__drm_gem_object_put(obj);
+}
+
+/**
+ * drm_gem_object_unreference_unlocked - release a GEM buffer object reference
+ * @obj: GEM buffer object
+ *
+ * This is a compatibility alias for drm_gem_object_put_unlocked() and should
+ * not be used by new code.
+ */
+static inline void
+drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
+{
+	drm_gem_object_put_unlocked(obj);
+}
+
+/**
+ * drm_gem_object_unreference - release a GEM buffer object reference
+ * @obj: GEM buffer object
+ *
+ * This is a compatibility alias for drm_gem_object_put() and should not be
+ * used by new code.
+ */
+static inline void drm_gem_object_unreference(struct drm_gem_object *obj)
+{
+	drm_gem_object_put(obj);
+}
 
 int drm_gem_handle_create(struct drm_file *file_priv,
 			  struct drm_gem_object *obj,