From: Noralf Trønnes Date: Tue, 7 Nov 2017 19:13:42 +0000 (+0100) Subject: drm/cma-helper: Turn to_drm_gem_cma_obj() into a macro X-Git-Tag: v4.16-rc1~96^2~32^2~42 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=8d25ccebef55b8fc47b674f24ccdccbef08e2f32;p=linux.git drm/cma-helper: Turn to_drm_gem_cma_obj() into a macro This allows the argument to be a const. The other option was to keep it an inline function and make the argument a const: static inline struct drm_gem_cma_object * to_drm_gem_cma_obj(const struct drm_gem_object *gem_obj) { return container_of(gem_obj, struct drm_gem_cma_object, base); } This will happily return a non-const pointer to the drm_gem_cma_object based on a const pointer to the contained drm_gem_object, thus creating const-safety problems. There was an attempt to fix the problem in the container_of() macro itself (see https://lkml.org/lkml/2017/5/19/381) but the patch seems to have fallen through the cracks. It would require turning this inline function into a macro. By making this a macro now, we will benefit from a possible future enhancement of container_of(). We don't loose type checking by doing this, container_of() takes care of that. Suggested-by: Laurent Pinchart Signed-off-by: Noralf Trønnes Reviewed-by: Laurent Pinchart Link: https://patchwork.freedesktop.org/patch/msgid/20171107191348.17555-7-noralf@tronnes.org --- diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h index 58a739bf15f1..7a3dcf0cf289 100644 --- a/include/drm/drm_gem_cma_helper.h +++ b/include/drm/drm_gem_cma_helper.h @@ -20,11 +20,8 @@ struct drm_gem_cma_object { void *vaddr; }; -static inline struct drm_gem_cma_object * -to_drm_gem_cma_obj(struct drm_gem_object *gem_obj) -{ - return container_of(gem_obj, struct drm_gem_cma_object, base); -} +#define to_drm_gem_cma_obj(gem_obj) \ + container_of(gem_obj, struct drm_gem_cma_object, base) #ifndef CONFIG_MMU #define DRM_GEM_CMA_UNMAPPED_AREA_FOPS \