From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2FC1C636CD for ; Mon, 19 Jul 2021 09:03:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A72E611EF for ; Mon, 19 Jul 2021 09:03:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235728AbhGSIWm (ORCPT ); Mon, 19 Jul 2021 04:22:42 -0400 Received: from mout.gmx.net ([212.227.17.21]:35513 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235073AbhGSIWk (ORCPT ); Mon, 19 Jul 2021 04:22:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1626685395; bh=hgrS4whYS4mlBgjCJJ3krDPj9t9aNc71BUlz4g1F6FU=; h=X-UI-Sender-Class:From:To:Cc:Subject:Date:In-Reply-To:References; b=OjiOCYEGAblNtLZA2LfU5MKYKfYvgZkOI2V+efNdUVRaFLdXbOOwFfPzGC+Ss/HoM aj+nHOhS8nGl9ao0SAckj/FAOKii+/IB21IczzqACldribc1YO7OzZZ1psBM47JAxA 7yXhTK7VV45tTk5eTcVKT8SSCGZHYnRugyFMi5Ds= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [87.130.101.138] ([87.130.101.138]) by web-mail.gmx.net (3c-app-gmx-bap33.server.lan [172.19.172.103]) (via HTTP); Mon, 19 Jul 2021 10:20:13 +0200 MIME-Version: 1.0 Message-ID: From: Lino Sanfilippo To: Vladimir Oltean Cc: Andrew Lunn , woojung.huh@microchip.com, UNGLinuxDriver@microchip.com, vivien.didelot@gmail.com, f.fainelli@gmail.com, davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Aw: Re: [PATCH 2/2] net: dsa: tag_ksz: dont let the hardware process the layer 4 checksum Content-Type: text/plain; charset=UTF-8 Date: Mon, 19 Jul 2021 10:20:13 +0200 Importance: normal Sensitivity: Normal In-Reply-To: <20210715143648.yutq6vceoblnhhfp@skbuf> References: <20210714191723.31294-1-LinoSanfilippo@gmx.de> <20210714191723.31294-3-LinoSanfilippo@gmx.de> <20210714194812.stay3oqyw3ogshhj@skbuf> <20210715065455.7nu7zgle2haa6wku@skbuf> <20210715143648.yutq6vceoblnhhfp@skbuf> X-UI-Message-Type: mail X-Priority: 3 X-Provags-ID: V03:K1:oyX0+TuW8PHL+WK/JEozk6jlWR2O/yBuSlUBcGgGWhBxNvMorJ0I01RBiHgA50eYXf8E8 8sgNFp+WL6gbGwdyFBwyhFH4Ts381FPUkIMPfHIFAqJ8tC7CDwHr1JQH2gjUMBT1BHMK2jbyKNl1 QPHt+BBnzcEbKXxy8Taqp5ShQ3wJ8Fkz4pEaGcD6hieK9aaGYKHhN4qg7Dpko3IUGgJj6h96lwkl 7y/cSU7rk2a5BDjeROD+oAJB2GF4sZ7kf2CQmEUyoSDBohoDpmvHmbDyDB+Isqg1xruY1Kq0JLw+ dY= X-UI-Out-Filterresults: notjunk:1;V03:K0:UrWgcxsN8To=:J4sw6C5qkIfBDmaTLY6kFg EkTgLaC4xKg6kQTcwnhoK/ud0HXNmD7R5bpeMUU7lHmCqEigX4+ZvHh/kbgk1diF+QmNF28dg O637nOtUORnFfMSXhRsQhjPOzwJXvuASxeI6DGqH0XFPAEc8/A+EOhcViRws0uZ3OWxvU4UlS 1uWWgeDagQ4MrBAMOf8kEn6KIYi7LVcfHGHy7+QhC+NwTNBoYwrR+vjxjkaw7vA6FnqczN2VC ctvf4jJr236Mk+Qf2UpCZW+Szwn8hON7Cxldg3Tm76UUZ6QCdl9jQRyfbg0gLPeAWhXBTqCTi h/PylXplAfWWFym4Emh5iXsGLU8jF8UpBzDsXVYK8J9qZVeV2KlwGC+fbbgb7s5+lCnz0ZATT OoxgLY7DNCWUwJ0cvVa6vnh+Kt9M8vLnVHbuELY9nOp/Oqd5o32XJHrpwA0MiFRDsfWcWKxU6 HlqE0Ce5cE7bzbEflOM6xD/75tmZCXJEioBf9+ED519gH81TGVfgYP4swb6+B2eYxsvcDBeU/ qbe0IIC1QyNyYPzfjySNUFdXf4vemlEXILsc2oZ4UA6zJxNvA+MCb02PcYIeaJC+3NM2/FRJJ aucRfPUnUQDRhK7UC59wn6/l/LwJv/S+ETOEtiezdQxcbFKuF0Ge8qDtDdtjqNwA/LWC8pJmm miNL7IAbbp+TBDDJpzY6U9pzqGg8eRnDoos8Z1kas4H5AFDMWXjWHgqh03iTKoK/0FF0gfukL X9Wv2Or/KIhj++KJaJaMpuhPftmoaOvEkbWE10TPmM2fQtOmLFZES21jMlrKWhaPqEHv5O3WB CcukA53MmfbJlgSwN3n2SPaF0U5lQ== Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, > Gesendet: Donnerstag, 15. Juli 2021 um 16:36 Uhr > Von: "Vladimir Oltean" > An: "Andrew Lunn" > Cc: "Lino Sanfilippo" , woojung.huh@microchip.com= , UNGLinuxDriver@microchip.com, vivien.didelot@gmail.com, f.fainelli@gmail= .com, davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, linux-= kernel@vger.kernel.org > Betreff: Re: [PATCH 2/2] net: dsa: tag_ksz: dont let the hardware proces= s the layer 4 checksum > > On Thu, Jul 15, 2021 at 03:08:53PM +0200, Andrew Lunn wrote: > > > - If we inherit NETIF_F_HW_CSUM from the master for tail taggers, it= is > > > actively detrimential to keep this feature enabled, as proven my L= ino. > > > As for header taggers, I fail to see how this would be helpful, si= nce > > > the DSA master would always fail to see the real IP header (it has > > > been pushed to the right by the DSA tag), and therefore, the DSA > > > master offload would be effectively bypassed. > > > > The Marvell MACs know about DSA and should be able to perform hardware > > checksumming. It is a long time since i looked at how this works, but > > i think there is a field in the descriptor which gets set with the > > offset to the IP header, so it work for DSA as well as EDSA. > > > > I _think_ Broadcom MACs also know about Broadcom tags and can do the > > right thing. > > > > So we need to be a bit careful here to prevent performance regressions > > for same vendor MAC+Switch combinations. > > Tell me more (show me some code). Do Marvell Ethernet controllers which > support TX checksumming with Marvell switches do different things > depending on whether DSA or EDSA is used? Because we can currently > toggle between DSA and EDSA at runtime. > > This new information means we can only accept Lino's patch 2/2 as-is for > the "net" tree, otherwise we will introduce regressions one way or > another. It will only be a partial fix for the particular case of KSZ > switches which probably have no DSA master counterpart to support TX > checksumming. > Should I then resend the series with patch 1 handling the NETIF_F_SG and NETIF_F_FRAGLIST flags (i.e. deleting them if tailroom is needed) in dsa_slave_setup_tagger() as you suggested and patch 2 as it is? Regards, Lino