| Message ID | 20160927074203.GA3968@akamai.com |
|---|---|
| State | Changes Requested |
| Delegated to: | Pablo Neira |
| Headers | show |
Hi Vishwanath Pai, 2016-09-27 15:42 GMT+08:00 Vishwanath Pai <vpai@akamai.com>: > 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); > } > } > -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 2016-09-27 at 03:42 -0400, Vishwanath Pai wrote: > Fix link error in 32bit arch because of 64bit division > > Division of 64bit integers will cause linker error undefined reference > to `__udivdi3'. Fix this by replacing divisions with div64_64 > > Signed-off-by: Vishwanath Pai <vpai@akamai.com> > > --- > net/netfilter/xt_hashlimit.c | 15 ++++++++------- > 1 file changed, 8 insertions(+), 7 deletions(-) > > diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c > index 44a095e..7fc694e 100644 > --- 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))) How can this be needed ? 0xFFFFFFFF is 32bits, compiler knows how to compute 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY_v1) itself, without using a 64 bit divide ! Please be selective. > /* 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) *\ Probably same remark here. > + if (user > div64_u64(0xFFFFFFFFFFFFFFFF, (HZ*CREDITS_PER_JIFFY))) > + 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); > } > } > -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index 44a095e..7fc694e 100644 --- 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))) /* 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))) + 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); } }
Fix link error in 32bit arch because of 64bit division Division of 64bit integers will cause linker error undefined reference to `__udivdi3'. Fix this by replacing divisions with div64_64 Signed-off-by: Vishwanath Pai <vpai@akamai.com> --- net/netfilter/xt_hashlimit.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)