net/mlx5e: Force CHECKSUM_UNNECESSARY for short ethernet frames
authorCong Wang <xiyou.wangcong@gmail.com>
Tue, 4 Dec 2018 06:14:04 +0000 (22:14 -0800)
committerSaeed Mahameed <saeedm@mellanox.com>
Sat, 19 Jan 2019 00:15:30 +0000 (16:15 -0800)
commit62a30d7e34c8f4e51984d25b6c2a7da229f2dc65
treed5ae7059af99e0809dd048f3de4d84d899515d34
parentd6952d4b95d3a6897fcea7446c97f59f8d24556b
net/mlx5e: Force CHECKSUM_UNNECESSARY for short ethernet frames

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 usually 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 'e63754b567b2 ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE ...")'
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.

Fixes: e63754b567b2 ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends"),
Cc: Eric Dumazet <edumazet@google.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Nikola Ciprich <nikola.ciprich@linuxbox.cz>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
drivers/net/ethernet/mellanox/mlx5/core/en_rx.c