Re: [PATCH net-next v4 02/12] udp: gso: Simplify handling length in GSO_PARTIAL

[Gal Pressman <gal@nvidia.com>]

On 13/05/2026 12:23, Alice Mikityanska wrote:
> On Wed, May 13, 2026, at 09:53, Gal Pressman wrote:
>> Hi Alice,
>>
>> On 12/05/2026 19:56, Alice Mikityanska wrote:
>>> From: Alice Mikityanska <alice@isovalent.com>
>>>
>>> Taking further the idea of commit b10b446ce7ad ("udp: gso: Use single
>>> MSS length in UDP header for GSO_PARTIAL"), simplify the implementation
>>> and fix the checksum (apparently ignored by hardware anyway).
>>>
>>> The mentioned commit started using msslen for uh->len, but still uses
>>> newlen to adjust uh->check. If the formula for check is fixed, newlen is
>>> assigned but never used before the loop, and newlen is overwritten after
>>> the loop. This makes msslen not really necessary, as we can reuse
>>> newlen, if we don't adjust mss before. The adjustment of mss can be
>>> simply dropped, because mss is not used anywhere else below.
>>>
>>> This brings us back to one variable, drops an unneeded arithmetic for
>>> mss, and fixes the UDP checksum.
>>>
>>> Signed-off-by: Alice Mikityanska <alice@isovalent.com>
>>> Cc: Gal Pressman <gal@nvidia.com>
>>> Reviewed-by: Willem de Bruijn <willemb@google.com>
>>
>> Heads up, this is going to conflict with this fix:
>> https://lore.kernel.org/netdev/20260513074349.2152146-1-gal@nvidia.com/
> 
> Thanks for the heads up! When I submitted mine, your patch wasn't on the
> list yet, so it's rather the other way around :). Anyway, let's combine
> our efforts, since we are fixing different aspects of the same area of
> code. I commented on your patch and suggested to base it on top of mine
> to avoid creating a new bug with the checksum. If my series doesn't get
> merged in this iteration, feel free to cherry-pick this commit, it's
> pretty much independent.

Right, but the fix goes to net.