On Mon, Dec 3, 2018 at 10:14 PM Cong Wang <xiyou.wangc...@gmail.com> wrote:
>
> When an ethernet frame is padded to meet the minimum ethernet frame
> size, the padding octets are not covered by the hardware checksum.
> Fortunately the padding octets are ususally zero's, which don't affect
> checksum. However, we have a switch which pads non-zero octets, this
> causes kernel hardware checksum fault repeatedly.
>
> Prior to commit 88078d98d1bb ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE
> are friends"),
> skb checksum was forced to be CHECKSUM_NONE when padding is detected.
> After it, we need to keep skb->csum updated, like what we do for RXFCS.
> However, fixing up CHECKSUM_COMPLETE requires to verify and parse IP
> headers, it is not worthy the effort as the packets are so small that
> CHECKSUM_COMPLETE can't save anything.
>
> I tested this patch with RXFCS on and off, it works fine without any
> warning in both cases.
>
> Fixes: 88078d98d1bb ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are
> friends"),
> Cc: Saeed Mahameed <sae...@mellanox.com>
> Cc: Eric Dumazet <eduma...@google.com>
> Cc: Tariq Toukan <tar...@mellanox.com>
> Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
Nacked-by: Cong Wang <xiyou.wangc...@gmail.com>
This patch has no value for upstream. Let's discard it.
Thanks!
