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=-7.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 230BAC433E0 for ; Tue, 2 Mar 2021 21:21:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E56A364F2A for ; Tue, 2 Mar 2021 21:21:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1837367AbhCBVTV (ORCPT ); Tue, 2 Mar 2021 16:19:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244196AbhCBS17 (ORCPT ); Tue, 2 Mar 2021 13:27:59 -0500 Received: from mail-ej1-x630.google.com (mail-ej1-x630.google.com [IPv6:2a00:1450:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 102E0C06121F; Tue, 2 Mar 2021 08:11:44 -0800 (PST) Received: by mail-ej1-x630.google.com with SMTP id mm21so35972845ejb.12; Tue, 02 Mar 2021 08:11:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=cimOH74ExOm9n45WQhr2uwq67qtoQ7z880rvlczqwuo=; b=lia4ZT8TqvrwoMgkKSX2e6p/voNPp4KfheU9My7YSyJu+O0vf/lx6oeOB5vWSztukm lW2fWp87EdzWpntwmu1+89J5j9Z3f8Onj787Jxn5Ii7wHzf0VpTGhhwPl454uK1O6Bjv 7KdxQocMnc7bcPuExxpeI4YVxuobUuPprW9/9aVbEc8NrLm+07ARj+HgiVDj9Zi39Dco DN+guwJTa5ufvMYqg3OgqjigwgfP6Wfvk/YNS7HZjM3/CRk//1gQf5PKVvOUQAGpLHqZ Hsb7XLHmgvkGN9Yg6eAMndxIgjeZEKCAy0f8EtVURCYgmpNFCBg43QLoGDO4GpKmU1hh BJfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=cimOH74ExOm9n45WQhr2uwq67qtoQ7z880rvlczqwuo=; b=SQToOhi7Cl2D5/dCeVVIkVDH8LvhBuIeYd/MZbEDwsOpZqbo4mF9NjyzUOcUGUzsRY 5KohYiEbyz8UMobeNGMeQdiGLMyzIcHzGdt/GyxTStDDBRb/4nB3l4PCJ7kfPDYK3dTO eM2X3/P87E/oYNTMqZurH+SIxhfo6ED5+qNIEO8wezLKWvuf/+dhjeykiPUCMA7rYoK7 l2SYaJfn2xRT2vqEhIBgYfv3UyidtWQaC+UeM8vbkwXyUa0+9D6Xh6m/UExJuGDFDDDH JoSazjJB/ulVKSPxdjTwo3hImvYQQfJMQNkzL1YuZdSoWslCYgiMKjr/NgIHBwWFlo5d b3yA== X-Gm-Message-State: AOAM531xPGmwl19braqoaZQrL798QJCSYB7LxfHzWCHCFaXdzaca3I10 fKQAcFe1iqqDy1UCTbr7n4M= X-Google-Smtp-Source: ABdhPJxBEHbIAr9oL6dyFLIaky9rTvZwAzmWifVZVvQpbPSK5A4ogtHIa5jmErDB3J/6JfqMld8AlQ== X-Received: by 2002:a17:906:71d3:: with SMTP id i19mr1210810ejk.347.1614701502805; Tue, 02 Mar 2021 08:11:42 -0800 (PST) Received: from skbuf ([188.25.217.13]) by smtp.gmail.com with ESMTPSA id q11sm17924852ejr.36.2021.03.02.08.11.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Mar 2021 08:11:42 -0800 (PST) Date: Tue, 2 Mar 2021 18:11:40 +0200 From: Vladimir Oltean To: Linus Walleij Cc: DENG Qingfang , Andrew Lunn , Vivien Didelot , Florian Fainelli , "David S. Miller" , Jakub Kicinski , Russell King , netdev , "linux-kernel@vger.kernel.org" Subject: Re: [RFC net-next] net: dsa: rtl8366rb: support bridge offloading Message-ID: <20210302161140.l3jtvkcm3tvlv5q3@skbuf> References: <20210224061205.23270-1-dqfext@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 02, 2021 at 05:05:00PM +0100, Linus Walleij wrote: > On Tue, Mar 2, 2021 at 4:58 AM DENG Qingfang wrote: > > On Mon, Mar 1, 2021 at 9:48 PM Linus Walleij wrote: > > > With my minor changes: > > > Tested-by: Linus Walleij > > > > How about using a mutex lock in port_bridge_{join,leave} ? > > In my opinion all functions that access multiple registers should be > > synchronized. > > That's one way, in some cases the framework (DSA) serialize > the accesses so I don't know if that already happens on a > higher level? Since it is accessed over a slow bus we should go > for mutex in that case indeed. DSA does not serialize this. The .port_bridge_join and .port_bridge_leave calls are initiated from the NETDEV_CHANGEUPPER net device event, which is called under rtnl_mutex (see call_netdevice_notifiers). This is pretty fundamental and I don't think it will ever change. However, if you still want to add an extra layer of locking (with code paths that for some reason are not under the rtnl_mutex), then go ahead, I suppose. It will be challenging to make sure they do something that isn't snake oil, though.