On Fri, 2019-01-25 at 10:31 -0800, Eric Dumazet wrote: > > On 01/25/2019 10:22 AM, Saeed Mahameed wrote: > > On Tue, 2019-01-22 at 13:30 -0800, Cong Wang wrote: > > > On Fri, Jan 18, 2019 at 4:25 PM Saeed Mahameed < > > > sae...@mellanox.com> > > > wrote: > > > > From: Cong Wang <xiyou.wangc...@gmail.com> > > > > > > I don't know why you want to make me as the author here, but I > > > never > > > agree on _your_ updates on my previous patch. > > > > > > Please see below. > > > > > > > sorry, i just took your patch and worked on top of it, i thought > > you > > would like to get the credit for this. > > > > I thought the issue was that the hardware csum provided by both mlx4 > and mlx5 only > covered the bytes included in the IP (v4 or v6) frame. > > Meaning that any non zero padding bytes are not checksummed.
in case of non IP, mlx5 will provide csum complete on the whole frame. > If this can not be fixed by a firmware change, then the fix has > nothing to do with a frame being > smaller than ETH_ZLEN + ETH_FCS_LEN > Again, most of the switches/routers that have non-zero padding bug are padding only small frames. > Alternative would be for the driver to trim the frame (pretend the > skb->len is exactly the expected one), > but one could argue that tcpdump should be able to see padding bytes. > That requires parsing the IP headers in the driver, we are trying to avoid that, this patch is not perfect but eliminates many of the csum warnings seen on mlx5. >
