Re: [PATCH] Fix link error in 32bit arch because of 64bit division
flat view
From: Liping Zhang <hidden>
Date: 2016-09-27 10:23:50
Also in:
netfilter-devel
Hi Vishwanath Pai, 2016-09-27 15:42 GMT+08:00 Vishwanath Pai [off-list ref]:
Fix link error in 32bit arch because of 64bit division
This should be "netfilter: xt_hashlimit: fix ... "
quoted hunk ↗ jump to hunk
--- 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.
quoted hunk ↗ jump to hunk
/* 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.
quoted hunk ↗ jump to hunk
+ 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); } }