From: Simon Horman <horms@kernel.org>
To: iugfdin <iugfdin@proton.me>
Cc: netdev@vger.kernel.org, Heiner Kallweit <hkallweit1@gmail.com>,
nic_swsd@realtek.com, Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@kernel.org>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH net 1/2] r8169: preserve checksum offload when packet padding is unnecessary
Date: Wed, 7 Oct 2026 16:34:38 +0100 [thread overview]
Message-ID: <20261007153438.GV83879@horms.kernel.org> (raw)
In-Reply-To: <179098478410.1174319.5605355405318252998.r8169-1@proton.me>
On Sat, Oct 03, 2026 at 12:07:54AM +0000, iugfdin wrote:
> rtl_quirk_packet_padto() returns the minimum packet length required by
> the padding quirks. For RTL8168evl and RTL8125-family chips this is at
> least ETH_ZLEN, even when the skb is already longer.
>
> rtl8169_features_check() treats that nonzero target as a boolean and
> therefore disables checksum offload for ordinary non-GSO
> CHECKSUM_PARTIAL packets on these chips. Packets that need no padding
> are unnecessarily checksummed in software.
>
> Compare the skb length with the padding target instead. Packets that
> actually need padding continue to use software checksumming; the
> existing short-frame and transport-offset checks are unchanged.
>
> Fixes: 8d520b4de3ed ("r8169: work around RTL8125 UDP hw bug")
> Assisted-by: LLM
> Signed-off-by: iugfdin <iugfdin@proton.me>
Please consider using your real name in the From header and Signed-off-by tag.
Apologies if I am misreading things and that is already the case.
> ---
> Tested with W=1 driver-target builds on net under x86-64
> allmodconfig and allyesconfig, and source-executing ASan/UBSan
> checks with modeled kernel/DMA/MMIO boundaries. No physical
> Realtek NIC was available; this is not an on-device test claim.
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2026-10-07 15:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-03 0:07 [PATCH net 0/2] r8169: fix checksum eligibility and failed TX batch progress iugfdin
2026-10-03 0:07 ` [PATCH net 1/2] r8169: preserve checksum offload when packet padding is unnecessary iugfdin
2026-10-07 15:34 ` Simon Horman [this message]
2026-10-08 0:27 ` Jakub Kicinski
2026-10-03 0:08 ` [PATCH net 2/2] r8169: flush pending transmit packets when an skb is dropped iugfdin
2026-10-07 15:34 ` Simon Horman
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