Hi Vishwanath Pai,
2016-09-27 15:42 GMT+08:00 Vishwanath Pai <[email protected]>:
> Fix link error in 32bit arch because of 64bit division
This should be "netfilter: xt_hashlimit: fix ... "
>
> --- a/net/netfilter/xt_hashlimit.c
> +++ b/net/netfilter/xt_hashlimit.c
> @@ -465,19 +465,20 @@ static u64 user2credits(u64 user, int revision)
> {
> if (revision == 1) {
> /* If multiplying would overflow... */
> - if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY_v1))
> + if (user > div64_u64(0xFFFFFFFF, (HZ*CREDITS_PER_JIFFY_v1)))
Here divisor and dividend are all 32-bit integer, so covert "/" to div64_u64
seems unnecessary.
> /* Divide first. */
> - return (user / XT_HASHLIMIT_SCALE) *\
> + return div64_u64(user, XT_HASHLIMIT_SCALE) *\
> HZ * CREDITS_PER_JIFFY_v1;
>
> - return (user * HZ * CREDITS_PER_JIFFY_v1) \
> - / XT_HASHLIMIT_SCALE;
> + return div64_u64((user * HZ * CREDITS_PER_JIFFY_v1),
> + XT_HASHLIMIT_SCALE);
> } else {
> - if (user > 0xFFFFFFFFFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
> - return (user / XT_HASHLIMIT_SCALE_v2) *\
> + if (user > div64_u64(0xFFFFFFFFFFFFFFFF,
> (HZ*CREDITS_PER_JIFFY)))
0xFFFFFFFFFFFFFFFF and "HZ*CREDITS_PER_JIFFY" are both
constant, and GCC will do constant folding optimization, so I think
convert "/" to div64_u64 here is also unnecessary.
> + return div64_u64(user, XT_HASHLIMIT_SCALE_v2) *\
> HZ * CREDITS_PER_JIFFY;
>
> - return (user * HZ * CREDITS_PER_JIFFY) /
> XT_HASHLIMIT_SCALE_v2;
> + return div64_u64((user * HZ * CREDITS_PER_JIFFY),
> + XT_HASHLIMIT_SCALE_v2);
> }
> }
>
