From: Paolo Abeni <pabeni@redhat.com>
To: Richard Gobert <richardbgobert@gmail.com>,
netdev@vger.kernel.org, ecree.xilinx@gmail.com,
willemdebruijn.kernel@gmail.com
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
horms@kernel.org, corbet@lwn.net, saeedm@nvidia.com,
tariqt@nvidia.com, mbloch@nvidia.com, leon@kernel.org,
dsahern@kernel.org, ncardwell@google.com, kuniyu@google.com,
shuah@kernel.org, sdf@fomichev.me, aleksander.lobakin@intel.com,
florian.fainelli@broadcom.com, alexander.duyck@gmail.com,
linux-kernel@vger.kernel.org, linux-net-drivers@amd.com
Subject: Re: [PATCH net-next v6 4/5] net: gro: remove unnecessary df checks
Date: Thu, 18 Sep 2025 10:10:18 +0200 [thread overview]
Message-ID: <c557acda-ad4e-4f07-a210-99c3de5960e2@redhat.com> (raw)
In-Reply-To: <20250916144841.4884-5-richardbgobert@gmail.com>
On 9/16/25 4:48 PM, Richard Gobert wrote:
> Currently, packets with fixed IDs will be merged only if their
> don't-fragment bit is set. This restriction is unnecessary since
> packets without the don't-fragment bit will be forwarded as-is even
> if they were merged together. The merged packets will be segmented
> into their original forms before being forwarded, either by GSO or
> by TSO. The IDs will also remain identical unless NETIF_F_TSO_MANGLEID
> is set, in which case the IDs can become incrementing, which is also fine.
>
> Note that IP fragmentation is not an issue here, since packets are
> segmented before being further fragmented. Fragmentation happens the
> same way regardless of whether the packets were first merged together.
I agree with Willem, that an explicit assertion somewhere (in
ip_do_fragmentation?!?) could be useful.
Also I'm not sure that "packets are segmented before being further
fragmented" is always true for the OVS forwarding scenario.
/P
next prev parent reply other threads:[~2025-09-18 8:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-16 14:48 [PATCH net-next v6 0/5] net: gso: restore outer ip ids correctly Richard Gobert
2025-09-16 14:48 ` [PATCH net-next v6 1/5] net: gro: remove is_ipv6 from napi_gro_cb Richard Gobert
2025-09-16 14:48 ` [PATCH net-next v6 2/5] net: gro: only merge packets with incrementing or fixed outer ids Richard Gobert
2025-09-22 19:28 ` Willem de Bruijn
2025-09-16 14:48 ` [PATCH net-next v6 3/5] net: gso: restore ids of outer ip headers correctly Richard Gobert
2025-09-22 19:35 ` Willem de Bruijn
2025-09-23 8:29 ` Richard Gobert
2025-09-16 14:48 ` [PATCH net-next v6 4/5] net: gro: remove unnecessary df checks Richard Gobert
2025-09-18 8:10 ` Paolo Abeni [this message]
2025-09-18 14:01 ` Richard Gobert
2025-09-22 8:19 ` Richard Gobert
2025-09-25 10:15 ` Paolo Abeni
2025-09-29 11:09 ` Ilya Maximets
2025-09-29 14:20 ` Willem de Bruijn
2025-09-16 14:48 ` [PATCH net-next v6 5/5] selftests/net: test ipip packets in gro.sh Richard Gobert
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