diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c index 2be6109d0093..5706d471692d 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c @@ -62,6 +62,13 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj, const struct drm_i915_gem_object_ops *ops, struct lock_class_key *key, unsigned flags) { + /* + * A gem object is embedded both in a struct ttm_buffer_object :/ and + * in a drm_i915_gem_object. Make sure they are aliased. + */ + BUILD_BUG_ON(offsetof(typeof(*obj), base) != + offsetof(typeof(*obj), __do_not_access.base)); + spin_lock_init(&obj->vma.lock); INIT_LIST_HEAD(&obj->vma.list); diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h index f5b46d11e6e6..d047ea126029 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h @@ -10,6 +10,7 @@ #include #include +#include #include #include "i915_active.h" @@ -99,7 +100,16 @@ struct i915_gem_object_page_iter { }; struct drm_i915_gem_object { - struct drm_gem_object base; + /* + * We might have reason to revisit the below since it wastes + * a lot of space for non-ttm gem objects. + * In any case, always use the accessors for the ttm_buffer_object + * when accessing it. + */ + union { + struct drm_gem_object base; + struct ttm_buffer_object __do_not_access; + }; const struct drm_i915_gem_object_ops *ops;