diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 604382143bcf..594b419b7d20 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -82,10 +82,18 @@ __x - (__x % (y)); \ } \ ) + +/* + * Divide positive or negative dividend by positive divisor and round + * to closest integer. Result is undefined for negative divisors. + */ #define DIV_ROUND_CLOSEST(x, divisor)( \ { \ - typeof(divisor) __divisor = divisor; \ - (((x) + ((__divisor) / 2)) / (__divisor)); \ + typeof(x) __x = x; \ + typeof(divisor) __d = divisor; \ + (((typeof(x))-1) >= 0 || (__x) >= 0) ? \ + (((__x) + ((__d) / 2)) / (__d)) : \ + (((__x) - ((__d) / 2)) / (__d)); \ } \ )