diff options
Diffstat (limited to 'include/linux/container_of.h')
| -rw-r--r-- | include/linux/container_of.h | 24 |
1 files changed, 11 insertions, 13 deletions
diff --git a/include/linux/container_of.h b/include/linux/container_of.h index 2f4944b791b8..1d898f9158b4 100644 --- a/include/linux/container_of.h +++ b/include/linux/container_of.h @@ -13,6 +13,7 @@ * @type: the type of the container struct this is embedded in. * @member: the name of the member within the struct. * + * WARNING: any const qualifier of @ptr is lost. */ #define container_of(ptr, type, member) ({ \ void *__mptr = (void *)(ptr); \ @@ -22,19 +23,16 @@ ((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. + * container_of_const - cast a member of a structure out to the containing + * structure and preserve the const-ness of the pointer + * @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_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))); }) +#define container_of_const(ptr, type, member) \ + _Generic(ptr, \ + const typeof(*(ptr)) *: ((const type *)container_of(ptr, type, member)),\ + default: ((type *)container_of(ptr, type, member)) \ + ) #endif /* _LINUX_CONTAINER_OF_H */ |