From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7FF9833D6D4; Thu, 19 Feb 2026 11:04:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771499099; cv=none; b=I79NDM4bVplWeDtKH48uKVPj3jguR80bVbfU+Rk7AKhEYeX8lAZ9MY0DxCRLxKW7+FGSTg96ij4/g0hk7g90LI5oT6Agt0nNvQ5r7cVtnk0GK4/hih5IFowgXraGywRIG/wK0izNkGvhoGmtNzp9EcOomQYw4R1x73WgpSf1X3o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771499099; c=relaxed/simple; bh=dypEWTVlE89/7xWq0IMW0YOdKTTzDMNo3Lyu5x3skpc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dqdy75vjS/wuHdF8z7SIOzC+3oqwvhUjrk2eOhxo8mwFkVRhIeq/BZuPc9qAlV0DXAiAB+FXMW8erUd6NdzUdoGOuK50BzHgvnU7dRLvrelcZY1euHPK6YiYm1Nu9P7AVpoTW3HFBZSEW+8WqdaKoMZDhM+9x/tfofhZ90PjZLk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gAtAjWUv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gAtAjWUv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA6CCC4CEF7; Thu, 19 Feb 2026 11:04:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771499099; bh=dypEWTVlE89/7xWq0IMW0YOdKTTzDMNo3Lyu5x3skpc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gAtAjWUvVDmTRToDssVu6nnZikmwl3JN7acRo2iLd0lEvmhvgfXflHnTynALA9mrq nTHeuHwRaRZY615Y8GKhJcQeL4r4a64YN20cDYuJFOE46yhNoSyO9SQ4ld+5JYiR3M N8RLdY8Ha/7M69wnFNBNtL95Y34OFoZi03vsTgYT97t5cJvJ20Ys+HF67rNOuxooQR 8jN+mOTIvtulLGPfmGWSn/cmg79C1iRwlPkT8P6G+XYIVviS8c6h4pa1rFzMlJIiIc 070DFDc3uDPap4Rjh1pjsjApp/txIT6RjA3087C0vptI1egOPum1zhC/Sc8rsfhVI2 HAnIbLUnh/1Sg== Date: Thu, 19 Feb 2026 12:04:56 +0100 From: Lorenzo Bianconi To: Jakub Kicinski Cc: Donald Hunter , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , Andrew Lunn , Tony Nguyen , Przemek Kitszel , Alexander Lobakin , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , Shuah Khan , Maciej Fijalkowski , Jakub Sitnicki , netdev@vger.kernel.org, bpf@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH bpf-next v3 1/5] netlink: specs: Add XDP RX checksum capability to XDP metadata specs Message-ID: References: <20260217-bpf-xdp-meta-rxcksum-v3-0-30024c50ba71@kernel.org> <20260217-bpf-xdp-meta-rxcksum-v3-1-30024c50ba71@kernel.org> <20260218174742.62a4074f@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="7EEdEqOMZc2AsItl" Content-Disposition: inline In-Reply-To: <20260218174742.62a4074f@kernel.org> --7EEdEqOMZc2AsItl Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > On Tue, 17 Feb 2026 09:33:56 +0100 Lorenzo Bianconi wrote: > > + * In case of success, ``ip_summed`` is set to the RX checksum result.= Possible > > + * values are: > > + * ``XDP_CHECKSUM_NONE`` > > + * ``XDP_CHECKSUM_UNNECESSARY`` > > + * ``XDP_CHECKSUM_COMPLETE`` > > + * > > + * In case of success, ``cksum_meta`` contains the hw computed checksu= m value > > + * for ``XDP_CHECKSUM_COMPLETE`` or the ``csum_level`` for > > + * ``XDP_CHECKSUM_UNNECESSARY``. It is set to 0 for ``XDP_CHECKSUM_NON= E`` >=20 > It's fairly common for NICs to report both csum complete and > unnecessary. Which one should the driver return in that case? Do you mean what is value for cksum_meta if we do not report csum_level for XDP_CHECKSUM_UNNECESSARY/CHECKSUM_UNNECESSARY use-case? (as suggested by Stanislav). My original idea is: - if the hw reports CHECKSUM_COMPLETE: - ip_summed =3D XDP_CHECKSUM_COMPLETE - cksum_meta contains the checksum computed by the hw - if the hw reports CHECKSUM_UNNECESSARY - ip_summed =3D XDP_CHECKSUM_UNNECESSARY - cksum_meta =3D csum_level <-- Stanislav suggests to drop this one - if the hw reports CHECKSUM_NONE - ip_summed =3D XDP_CHECKSUM_NONE - cksum_meta =3D 0 Regards, Lorenzo > What if the user prefers the other one?.. --7EEdEqOMZc2AsItl Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTquNwa3Txd3rGGn7Y6cBh0uS2trAUCaZbuWAAKCRA6cBh0uS2t rK3sAP0Y8MEfTYmbOSyx5stUp9dR847DtJFisjm3SerE8v89VgEAxRUCoRfB45R8 ogSiJLBtXUXr8+9VJlQ99d28Dja/LgY= =gmGu -----END PGP SIGNATURE----- --7EEdEqOMZc2AsItl--