diff options
Diffstat (limited to 'include/linux/overflow.h')
| -rw-r--r-- | include/linux/overflow.h | 44 |
1 files changed, 37 insertions, 7 deletions
diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 0c7e3dcfe867..154ed0dbb43f 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -389,25 +389,38 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) struct_size((type *)NULL, member, count) /** - * _DEFINE_FLEX() - helper macro for DEFINE_FLEX() family. - * Enables caller macro to pass (different) initializer. + * __DEFINE_FLEX() - helper macro for DEFINE_FLEX() family. + * Enables caller macro to pass arbitrary trailing expressions * * @type: structure type name, including "struct" keyword. * @name: Name for a variable to define. * @member: Name of the array member. * @count: Number of elements in the array; must be compile-time const. - * @initializer: initializer expression (could be empty for no init). + * @trailer: Trailing expressions for attributes and/or initializers. */ -#define _DEFINE_FLEX(type, name, member, count, initializer...) \ +#define __DEFINE_FLEX(type, name, member, count, trailer...) \ _Static_assert(__builtin_constant_p(count), \ "onstack flex array members require compile-time const count"); \ union { \ u8 bytes[struct_size_t(type, member, count)]; \ type obj; \ - } name##_u initializer; \ + } name##_u trailer; \ type *name = (type *)&name##_u /** + * _DEFINE_FLEX() - helper macro for DEFINE_FLEX() family. + * Enables caller macro to pass (different) initializer. + * + * @type: structure type name, including "struct" keyword. + * @name: Name for a variable to define. + * @member: Name of the array member. + * @count: Number of elements in the array; must be compile-time const. + * @initializer: Initializer expression (e.g., pass `= { }` at minimum). + */ +#define _DEFINE_FLEX(type, name, member, count, initializer...) \ + __DEFINE_FLEX(type, name, member, count, = { .obj initializer }) + +/** * DEFINE_RAW_FLEX() - Define an on-stack instance of structure with a trailing * flexible array member, when it does not have a __counted_by annotation. * @@ -419,9 +432,12 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) * Define a zeroed, on-stack, instance of @type structure with a trailing * flexible array member. * Use __struct_size(@name) to get compile-time size of it afterwards. + * Use __member_size(@name->member) to get compile-time size of @name members. + * Use STACK_FLEX_ARRAY_SIZE(@name, @member) to get compile-time number of + * elements in array @member. */ #define DEFINE_RAW_FLEX(type, name, member, count) \ - _DEFINE_FLEX(type, name, member, count, = {}) + __DEFINE_FLEX(type, name, member, count, = { }) /** * DEFINE_FLEX() - Define an on-stack instance of structure with a trailing @@ -436,8 +452,22 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) * Define a zeroed, on-stack, instance of @TYPE structure with a trailing * flexible array member. * Use __struct_size(@NAME) to get compile-time size of it afterwards. + * Use __member_size(@NAME->member) to get compile-time size of @NAME members. + * Use STACK_FLEX_ARRAY_SIZE(@name, @member) to get compile-time number of + * elements in array @member. */ #define DEFINE_FLEX(TYPE, NAME, MEMBER, COUNTER, COUNT) \ - _DEFINE_FLEX(TYPE, NAME, MEMBER, COUNT, = { .obj.COUNTER = COUNT, }) + _DEFINE_FLEX(TYPE, NAME, MEMBER, COUNT, = { .COUNTER = COUNT, }) + +/** + * STACK_FLEX_ARRAY_SIZE() - helper macro for DEFINE_FLEX() family. + * Returns the number of elements in @array. + * + * @name: Name for a variable defined in DEFINE_RAW_FLEX()/DEFINE_FLEX(). + * @array: Name of the array member. + */ +#define STACK_FLEX_ARRAY_SIZE(name, array) \ + (__member_size((name)->array) / sizeof(*(name)->array) + \ + __must_be_array((name)->array)) #endif /* __LINUX_OVERFLOW_H */ |