On Friday 30 September 2016, Eric Dumazet wrote: > On Fri, 2016-09-30 at 18:05 +0200, Arnd Bergmann wrote: > > net/netfilter/xt_hashlimit.c | 17 ++++++++++------- > > 1 file changed, 10 insertions(+), 7 deletions(-) > > > > diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c > > index 44a095ecc7b7..3d5525df6eb3 100644 > > --- a/net/netfilter/xt_hashlimit.c > > +++ b/net/netfilter/xt_hashlimit.c > > @@ -464,20 +464,23 @@ static u32 xt_hashlimit_len_to_chunks(u32 len) > > static u64 user2credits(u64 user, int revision) > > { > > if (revision == 1) { > > + u32 user32 = user; /* use 32-bit division */ > > + > > This looks dangerous to me. Have you really tried all possible cases ? Yes, I'm pretty certain about that: The 11d5f15723c9 patch that introduced this kept the existing implementation for the revision==1 case, except for changing the types. > Caller (even if using revision == 1) does > user2credits(cfg->avg * cfg->burst, revision); > > Since this is not a fast path, I would prefer to keep the 64bit divide. > > Vishwanath version looks safer. Ok, fair enough. I couldn't tell how much of a fast path this was, and it's more a general issue that I see with other developers blindly using div_u64() whenever getting this link error. Since I already had the patch by the time I saw the other one (which is also at v3 and got comments), I just sent it out along with the other two patches I had for netfilter. I also ended up introducing a typo in a last-minute change, so I'll let Vishwanath and you work out the best implementation and withdraw my version. Arnd -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html