From: Stanislav Fomichev <sdf.kernel@gmail.com>
To: Rongzheng Wang <testwrzwrz@gmail.com>
Cc: netdev@vger.kernel.org,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
Magnus Karlsson <magnus.karlsson@intel.com>,
Jason Xing <kerneljasonxing@gmail.com>,
Stanislav Fomichev <sdf@google.com>,
Jesper Dangaard Brouer <hawk@kernel.org>,
stable@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v3 1/2] xsk: defer software checksum until the skb is complete
Date: Wed, 28 Oct 2026 08:57:42 -0700 [thread overview]
Message-ID: <auIbb0qeWoJ_eKw0@devvm16445.scu0.facebook.com> (raw)
In-Reply-To: <20261028025026.11401-2-testwrzwrz@gmail.com>
On 10/28, Rongzheng Wang wrote:
> When XDP_UMEM_TX_SW_CSUM is used with multi-buffer TX, xsk_skb_metadata()
> calls skb_checksum_help() while only the first descriptor has been added to
> the skb. The checksum therefore covers just the first fragment, and
> skb_checksum_help() sets ip_summed to CHECKSUM_NONE, so the remaining
> fragments are never included in the checksum.
>
> Move the software checksum calculation to the point where the last
> descriptor has been added to the skb.
>
> On a checksum failure the packet is now dropped instead of being returned
> to the application for a retry. This path is not reachable with the
> existing metadata validation, but the behavior change is intentional.
>
> Fixes: 11614723af26 ("xsk: Add option to calculate TX checksum in SW")
> Cc: stable@vger.kernel.org
> Signed-off-by: Rongzheng Wang <testwrzwrz@gmail.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
next prev parent reply other threads:[~2026-10-28 15:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-28 2:50 [PATCH net v3 0/2] xsk: fix multi-buffer TX software checksum Rongzheng Wang
2026-10-28 2:50 ` [PATCH net v3 1/2] xsk: defer software checksum until the skb is complete Rongzheng Wang
2026-10-28 13:21 ` Maciej Fijalkowski
2026-10-28 15:55 ` [PATCH net v3 2/2] selftests/bpf: cover AF_XDP multi-buffer TX software checksum Rongzheng Wang
2026-10-28 15:57 ` Stanislav Fomichev [this message]
2026-10-28 2:50 ` Rongzheng Wang
2026-10-28 13:20 ` Maciej Fijalkowski
2026-10-28 16:38 ` Rongzheng Wang
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