From: Andrew Lunn <andrew@lunn.ch>
To: Jisheng Zhang <jszhang@kernel.org>
Cc: Maxime Chevallier <maxime.chevallier@bootlin.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: stmmac: Disable checksum insertion for XDP frame TX
Date: Tue, 29 Sep 2026 22:29:14 +0200 [thread overview]
Message-ID: <f0d8c25f-96e1-4da8-af6c-3286610338ba@lunn.ch> (raw)
In-Reply-To: <20260929121025.20821-1-jszhang@kernel.org>
On Tue, Sep 29, 2026 at 08:10:25PM +0800, Jisheng Zhang wrote:
> stmmac enables TX checksum insertion for XDP frames whenever the queue
> supports it. XDP frames carry no TX checksum offload request, so this
> can overwrite a checksum already present in the packet.
>
> Pass false to stmmac_prepare_tx_desc() when transmitting an XDP frame
> so that the packet is sent with its checksum fields unchanged.
This seems odd to me.
If the frame contains a checksum, it is either correct, and the
hardware calculated one will come out the same, not an issue. Or the
checksum in the frame is actually wrong, because the frame has got
mangled by eBPF before sending it out, and you want the hardware to
calculate the correct value.
What an i missing?
Andrew
next prev parent reply other threads:[~2026-09-29 20:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-29 12:10 [PATCH] net: stmmac: Disable checksum insertion for XDP frame TX Jisheng Zhang
2026-09-29 12:34 ` netdev-bot+sinfo
2026-09-29 20:29 ` Andrew Lunn [this message]
2026-10-05 23:28 ` Jakub Kicinski
2026-10-02 6:10 ` netdev-bot+sashiko
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