HelenOS sources

div_round_up       83 uspace/app/mkexfat/mkexfat.c #define div_round_up(a, b) (((a) + (b) - 1) / (b))
div_round_up       60 uspace/app/mkfat/mkfat.c #define div_round_up(a, b) (((a) + (b) - 1) / (b))
HelenOS homepage, sources at GitHub