netdev - Re: [PATCH net] net/mlx4_en: Force CHECKSUM

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Message-ID: <CANn89iKXNVBrUpBR6AgarrVC1_kPMQLmiwJDcdQ4CrYex_hO2Q@mail.gmail.com>
Date:   Thu, 31 Jan 2019 11:42:04 -0800
From:   Eric Dumazet <edumazet@...gle.com>
To:     Saeed Mahameed <saeedm@...lanox.com>
Cc:     Eran Ben Elisha <eranbe@...lanox.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Tariq Toukan <tariqt@...lanox.com>
Subject: Re: [PATCH net] net/mlx4_en: Force CHECKSUM_NONE for short ethernet frames

On Thu, Jan 31, 2019 at 11:27 AM Saeed Mahameed <saeedm@...lanox.com> wrote:
>
> Are you sure ? you are claiming that the hardware will skip csum
> complete i.e cqe->checksum will be 0xffff for padded short IP frames.
> i don't think this is the case, the whole bug is that the hw does
> provide a partial cqe->checksum (i.e doesn't included the padding
> bytes) even for short eth frames.

If the padding is not included, then cqe->checksum is 0xFFFF for
correctly received frames.

Otherwise, what would be cqe->checksum in this case ? A random value ?