A useful use case for min_t and max_t is comparing two values with larger type. For example comparing an u64 and an u32, usually we do not want to truncate the u64, so we need use min_t or max_t with u64. To simplify the usage introducing two more macros min_lt and max_lt, 'lt' means larger type. Signed-off-by: Dave Young --- include/linux/kernel.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- linux.orig/include/linux/kernel.h +++ linux/include/linux/kernel.h @@ -798,6 +798,19 @@ static inline void ftrace_dump(enum ftra type __max2 = (y); \ __max1 > __max2 ? __max1: __max2; }) +/* + * use type of larger size in min_lt and max_lt + */ +#define min_lt(x, y) ({ \ + int sx = sizeof(typeof(x)); \ + int sy = sizeof(typeof(y)); \ + sx > sy ? min_t(typeof(x), x, y) : min_t(typeof(y), x, y); }) + +#define max_lt(x, y) ({ \ + int sx = sizeof(typeof(x)); \ + int sy = sizeof(typeof(y)); \ + sx > sy ? max_t(typeof(x), x, y) : max_t(typeof(y), x, y); }) + /** * clamp_t - return a value clamped to a given range using a given type * @type: the type of variable to use