drm/gem: create drm_gem_dumb_destroy

All the gem based kms drivers really want the same function to
destroy a dumb framebuffer backing storage object.

So give it to them and roll it out in all drivers.

This still leaves the option open for kms drivers which don't use GEM
for backing storage, but it does decently simplify matters for gem
drivers.

Acked-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Ben Skeggs <skeggsb@gmail.com>
Reviwed-by: Rob Clark <robdclark@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 1f76572..9ab038c 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -244,6 +244,20 @@
 EXPORT_SYMBOL(drm_gem_handle_delete);
 
 /**
+ * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
+ * 
+ * This implements the ->dumb_destroy kms driver callback for drivers which use
+ * gem to manage their backing storage.
+ */
+int drm_gem_dumb_destroy(struct drm_file *file,
+			 struct drm_device *dev,
+			 uint32_t handle)
+{
+	return drm_gem_handle_delete(file, handle);
+}
+EXPORT_SYMBOL(drm_gem_dumb_destroy);
+
+/**
  * Create a handle for this object. This adds a handle reference
  * to the object, which includes a regular reference count. Callers
  * will likely want to dereference the object afterwards.