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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 2507FC07E96 for ; Thu, 15 Jul 2021 15:50:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 029506128C for ; Thu, 15 Jul 2021 15:50:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239415AbhGOPxm (ORCPT ); Thu, 15 Jul 2021 11:53:42 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:57158 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238841AbhGOPxj (ORCPT ); Thu, 15 Jul 2021 11:53:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=1EFyQ8ie4h3mbGIJ1dxorPzj8uRnod+uetVD2o2OJKM=; b=mgkXGI/nwWsq2mDsXt8XTySciO kstWDHDz03080VYmuyyETkxNbVV3hSV5X/npVOZYSAjAOkQPNJlPoOb/wprd5cKLOsuQqVpX2JGEE uqXhnOjkAtQtwLtvihB5K6dfOTarIRKHMhhiO2oRWAWduMX0KvktJPPm6XkAlviqlNPY=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1m43dE-00DVG6-Hv; Thu, 15 Jul 2021 17:50:36 +0200 Date: Thu, 15 Jul 2021 17:50:36 +0200 From: Andrew Lunn To: Vladimir Oltean 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 Subject: Re: [PATCH 2/2] net: dsa: tag_ksz: dont let the hardware process the layer 4 checksum Message-ID: References: <20210714191723.31294-1-LinoSanfilippo@gmx.de> <20210714191723.31294-3-LinoSanfilippo@gmx.de> <20210714194812.stay3oqyw3ogshhj@skbuf> <20210715065455.7nu7zgle2haa6wku@skbuf> <20210715143648.yutq6vceoblnhhfp@skbuf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210715143648.yutq6vceoblnhhfp@skbuf> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > Tell me more (show me some code). https://elixir.bootlin.com/linux/latest/source/drivers/net/ethernet/marvell/mvneta.c#L1747 and https://elixir.bootlin.com/linux/latest/source/drivers/net/ethernet/marvell/mvneta.c#L1944 It uses skb_network_offset(skb) to know where the real header is. This should work independent of DSA or EDSA. mvpp2_main.c looks to have something similar. The older mv643xx_eth.c also has something, but it is more subtle. Ah, found it: https://elixir.bootlin.com/linux/latest/source/drivers/net/ethernet/marvell/mv643xx_eth.c#L683 > I expect Marvell switches to be equally broken on the Broadcom genet > controller? Maybe. Depends on how genet works. A Broadcom switch connected to a Marvell MAC probably works, since the code is generic. It should work for any switch which uses head tagging, although mv643xx_eth.c is limited to 4 or 8 byte tags. Andrew