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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B516CC433EF for ; Tue, 10 May 2022 16:54:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=xPyJp8mUVdN2l2JXufR7k0AMfBF07t8Zy2n/rE0TPSg=; b=SqCMb2H0doIATf 5xzHN5xxcaF+rQlcQtqr+ySzNFxptNn9HnDmR8fDylOtG5FsAKFClQ9CEQMGSBq/xvhUEjnHOCjIn ekG4VfnBhrlwNY48kqN8FxTKUZB1m8WIADqdfFkIjnoi11S7IdfojyJacaNBH/zHTjhSzZLg2Aot9 lTYHRRzj9dyO/CiR6D9AGsTOem2WK8OTgNgj9ACQ1frgsXUvfcWThknz/wmFc8TWbNY7V/zBQjzQk eUxZQyuTCw40TKDOIDj1iequ6uep+73ge0bVToD4qhYv4Wc2SUJBCARY5mpcTTuUoSXIuypT9NnyX bwQI/sDiWgiwQiZIZ/FQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1noT6P-003ECe-QP; Tue, 10 May 2022 16:52:51 +0000 Received: from mail-ej1-x631.google.com ([2a00:1450:4864:20::631]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1noT6H-003E6X-5e; Tue, 10 May 2022 16:52:43 +0000 Received: by mail-ej1-x631.google.com with SMTP id ks9so27750490ejb.2; Tue, 10 May 2022 09:52:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=9xQwPtQrBfYT0IuemJx5F5so+crXxKK0HLvlBxjKC0s=; b=Okxteym8CaF/RHkBfO6Cp/WIgRcGbMBTJWIdNmMU19vXsWaAS8Z9L5ircpFp6VDy1S u10DkF0PLDeKl0gv5ijUtxkdcF6bG192cWFecvN8MBUJG7Gf6mTiy5C5HhKL4yKu+y7C fuY6AdEp9N1XEYZGCa4lJVnIb7TNode2Iu5C1xlRmg0nS7mbu3qxTeimBa81215XyjFo QElNUXkGIvL4YkC8lKNY8VCKfeTD0cAqUcjHZxtS/9ZzoiyeCWdvf6MDRaohKXFJocJ4 hgsSm0nftb8Eh1JEkwsZlH1sB4qIgwF0i7eJAzKg0c4C7PNz0ybEYElL1dvCdzxHrOvq D4Aw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=9xQwPtQrBfYT0IuemJx5F5so+crXxKK0HLvlBxjKC0s=; b=zS2y2QUhaHoNVP0Uw+lJxVauEy+FRpUiFvA0fkRkwo7u6/pWvNPZOV5+7XhVrYs78K D0zNjfeq16HyiGl6ud1gEWWyzp/anZd4OPhJVo1StIYGTXSdsJHZaMj5nHha04EKQKyX niZlkk8JV3GYZgRjNGZ52kbJdlc+Rzu/5cy1My8qkkDv6ZBq7KTBJD3PK6+u0x/qf0JA 9JXS8+LEsK3TLxSlHF00CAk06Mrx82vCcGtf3SNEk9L6ixJ/Rgo09OsvQTnMLpp4STDI F2aOi89JUppLq4Q5qXEXkzUOab/ma7gnCs/A3xm5apusDK1dz4jQrzYLif5tjaIMqI48 cOrA== X-Gm-Message-State: AOAM533bkRPzD99450k9xbqBJ2E5a2SNrv3ioVxWJDRLrb907qx8C5Ea Rer0AZ/3uqqF884mW4X5LJI= X-Google-Smtp-Source: ABdhPJxZw7qCY5xAugBz1OmSZd7IfwPIm4rayHyJ2D2Dl9oe0PTmAbGz9w3tCVGoNe698i+vy9lkAw== X-Received: by 2002:a17:907:d88:b0:6f5:1321:37ed with SMTP id go8-20020a1709070d8800b006f5132137edmr20817558ejc.67.1652201556379; Tue, 10 May 2022 09:52:36 -0700 (PDT) Received: from skbuf ([188.25.160.86]) by smtp.gmail.com with ESMTPSA id a21-20020a170906685500b006f3ef214dffsm6221861ejs.101.2022.05.10.09.52.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 May 2022 09:52:35 -0700 (PDT) Date: Tue, 10 May 2022 19:52:33 +0300 From: Vladimir Oltean To: Felix Fietkau Cc: Sean Wang , Landen Chao , DENG Qingfang , Andrew Lunn , Vivien Didelot , Florian Fainelli , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Matthias Brugger , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] net: dsa: tag_mtk: add padding for tx packets Message-ID: <20220510165233.yahsznxxb5yq6rai@skbuf> References: <20220510094014.68440-1-nbd@nbd.name> <20220510123724.i2xqepc56z4eouh2@skbuf> <5959946d-1d34-49b9-1abe-9f9299cc194e@nbd.name> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5959946d-1d34-49b9-1abe-9f9299cc194e@nbd.name> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220510_095241_264579_27FB0804 X-CRM114-Status: GOOD ( 15.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, May 10, 2022 at 04:52:16PM +0200, Felix Fietkau wrote: > > On 10.05.22 14:37, Vladimir Oltean wrote: > > On Tue, May 10, 2022 at 11:40:13AM +0200, Felix Fietkau wrote: > > > Padding for transmitted packets needs to account for the special tag. > > > With not enough padding, garbage bytes are inserted by the switch at the > > > end of small packets. > > > > I don't think padding bytes are guaranteed to be zeroes. Aren't they > > discarded? What is the issue? > With the broken padding, ARP requests are silently discarded on the receiver > side in my test. Adding the padding explicitly fixes the issue. > > - Felix Ok, I'm not going to complain too much about the patch, but I'm still curious where are the so-called "broken" packets discarded. I think the receiving MAC should be passing up to software a buffer without the extra padding beyond the L2 payload length (at least that's the behavior I'm familiar with). _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel