kern/40723: Disabling multicast on vlan interface caused kernel panic

[Gregory Bond]

>  Could someone tell me the file where the ROUNDUP() macro/function is defined?

Brute Force way:

hellcat$ find /usr/src -name '*.h' -print0 | xargs -0 grep "define *ROUNDUP"
/usr/src/sys/gmon.h:#define ROUNDUP(x,y)       roundup(x,y)
hellcat$

Let-someone-else-do-the-brute-force way:

http://minnie.tuhs.org/FreeBSD-srctree/FreeBSD.html