• Saeed Mahameed's avatar
    net/mlx4_en: Force CHECKSUM_NONE for short ethernet frames · fde4151c
    Saeed Mahameed authored
    [ Upstream commit 29dded89 ]
    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, it is not guaranteed. For example, switches might
    choose to make other use of these octets.
    This repeatedly causes kernel hardware checksum fault.
    Prior to the cited commit below, skb checksum was forced to be
    CHECKSUM_NONE when padding is detected. After it, we need to keep
    skb->csum updated. However, fixing up CHECKSUM_COMPLETE requires to
    verify and parse IP headers, it does not worth the effort as the packets
    are so small that CHECKSUM_COMPLETE has no significant advantage.
    Future work: when reporting checksum complete is not an option for
    IP non-TCP/UDP packets, we can actually fallback to report checksum
    unnecessary, by looking at cqe IPOK bit.
    Fixes: 88078d98
     ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends")
    Cc: Eric Dumazet <edumazet@google.com>
    Signed-off-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
    Signed-off-by: default avatarTariq Toukan <tariqt@mellanox.com>
    Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
en_rx.c 35 KB