/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_CONTAINER_OF_H #define _LINUX_CONTAINER_OF_H #include <linux/build_bug.h> #include <linux/err.h> #define typeof_member(T, m) typeof(((T*)0)->m) /** * container_of - cast a member of a structure out to the containing structure * @ptr: the pointer to the member. * @type: the type of the container struct this is embedded in. * @member: the name of the member within the struct. * */ #define container_of(ptr, type, member) ({ \ void *__mptr = (void *)(ptr); \ static_assert(__same_type(*(ptr), ((type *)0)->member) || \ __same_type(*(ptr), void), \ "pointer type mismatch in container_of()"); \ ((type *)(__mptr - offsetof(type, member))); }) /** * container_of_safe - cast a member of a structure out to the containing structure * @ptr: the pointer to the member. * @type: the type of the container struct this is embedded in. * @member: the name of the member within the struct. * * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged. */ #define container_of_safe(ptr, type, member) ({ \ void *__mptr = (void *)(ptr); \ static_assert(__same_type(*(ptr), ((type *)0)->member) || \ __same_type(*(ptr), void), \ "pointer type mismatch in container_of_safe()"); \ IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \ ((type *)(__mptr - offsetof(type, member))); }) #endif /* _LINUX_CONTAINER_OF_H */