On Wed, 17 Sep 2008, Atsushi Nemoto wrote: > On Wed, 17 Sep 2008 11:40:01 +0100 (BST), "Maciej W. Rozycki" <macro@xxxxxxxxxxxxxx> wrote: > > > and it seems to fix the problem for me. Can you comment? > > > > It seems obvious that a carry from the bit #15 in the last addition of > > the passed checksum -- ADDC(sum, a2) -- will negate the effect of the > > folding. However a simpler fix should do as well. Try if the following > > patch works for you. Please note this is completely untested and further > > optimisation is possible, but I've skipped it in this version for clarity. > > Well, csum_partial()'s return value is __wsum (32-bit). So strictly > there is no need to folding into 16-bit. Hmm, what's the purpose of doing the fold in csum_partial() then? Anyway, having looked at the code again the byte swap at the end means the passed checksum should be added afterwards, so my proposal is incorrect. Your suggestion to use 32-bit addition in all cases is certainly valid. Maciej
