drm/radeon: introduce gem_to_radeon_bo helper

... and switch it to container_of upcasting.

v2: converted new pageflip code-paths.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_fb.c b/drivers/gpu/drm/radeon/radeon_fb.c
index cb968f9..28431e7 100644
--- a/drivers/gpu/drm/radeon/radeon_fb.c
+++ b/drivers/gpu/drm/radeon/radeon_fb.c
@@ -90,7 +90,7 @@
 
 static void radeonfb_destroy_pinned_object(struct drm_gem_object *gobj)
 {
-	struct radeon_bo *rbo = gobj->driver_private;
+	struct radeon_bo *rbo = gem_to_radeon_bo(gobj);
 	int ret;
 
 	ret = radeon_bo_reserve(rbo, false);
@@ -128,7 +128,7 @@
 		       aligned_size);
 		return -ENOMEM;
 	}
-	rbo = gobj->driver_private;
+	rbo = gem_to_radeon_bo(gobj);
 
 	if (fb_tiled)
 		tiling_flags = RADEON_TILING_MACRO;
@@ -202,7 +202,7 @@
 	mode_cmd.depth = sizes->surface_depth;
 
 	ret = radeonfb_create_pinned_object(rfbdev, &mode_cmd, &gobj);
-	rbo = gobj->driver_private;
+	rbo = gem_to_radeon_bo(gobj);
 
 	/* okay we have an object now allocate the framebuffer */
 	info = framebuffer_alloc(0, device);
@@ -403,14 +403,14 @@
 	struct radeon_bo *robj;
 	int size = 0;
 
-	robj = rdev->mode_info.rfbdev->rfb.obj->driver_private;
+	robj = gem_to_radeon_bo(rdev->mode_info.rfbdev->rfb.obj);
 	size += radeon_bo_size(robj);
 	return size;
 }
 
 bool radeon_fbdev_robj_is_fb(struct radeon_device *rdev, struct radeon_bo *robj)
 {
-	if (robj == rdev->mode_info.rfbdev->rfb.obj->driver_private)
+	if (robj == gem_to_radeon_bo(rdev->mode_info.rfbdev->rfb.obj))
 		return true;
 	return false;
 }