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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=unavailable 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 32FC9C4360F for ; Wed, 3 Apr 2019 09:58:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00FF020830 for ; Wed, 3 Apr 2019 09:58:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rsKHSM7M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726486AbfDCJ6o (ORCPT ); Wed, 3 Apr 2019 05:58:44 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:34384 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725954AbfDCJ6n (ORCPT ); Wed, 3 Apr 2019 05:58:43 -0400 Received: by mail-wm1-f66.google.com with SMTP id r186so4427287wmf.1; Wed, 03 Apr 2019 02:58:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=jJhJoAKR6Xx6zdUywkAozy/HWnK00UYRpu6873wjNrU=; b=rsKHSM7Mt25mKPrreYX61hjNPRc/lww1vVqGlWdGAkivw7QsbhWflbiIS+Dfizc59q MbLL8sd/AIwsVwqSDJdToqHZohfcvhfNap6oWSSYnKqKGnGnIaB6pOFbau5Ruxn1A94s qHIaEbXXZNbTB+tP2roN8WgFvbkTk90CSEUHLW7G1zzq6Uttfpa86CKGygPfKBZwjIfs OSkulBTJd+q8mGnz7AQYYYc2IXvv2G/J/2pGNKnqnXcOk6AXX0SpOg9o9kMjZvZ4VCf9 Brybm5pTMsci0sTrHKrjp28oI2k12SFChgO/bfppRaAmfPWIy0SrEAu1FpVrAD/ZoXQD K17w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=jJhJoAKR6Xx6zdUywkAozy/HWnK00UYRpu6873wjNrU=; b=VHpwtwP+ikJ7SLK4Wq7LdHiq3qmOwPQACFhuXa9ejZUoOG2LHITtUYzzeWHb2TJMHM q4PGjcDhpgTNhjl2CHSyABZa22vUjWrOfyTtlk/hLAXh2JjhvviLUPER1oPR7E90uX3L i7u6i4B4jTRsOvhi0y+HY5fkjqCx6S6e4YA8D4Rq+BCjyJ7axsh0+uzLwX57T4nqYxdn I4ABmMku7fu/35d8HvR6wUu6taSPOO++UKjb28ptqjIbmZQhAj8/QskAiXdXyKlAOfzD k28kpJMCIUMq+0Q4+oR/rJypyzB/2NdexSp0yYECe1U+8zCDswTN27Tbu6m2N6CnGtxr r55g== X-Gm-Message-State: APjAAAXU3Uj2PER4Vb2s+wjlb/lV/vuPcvATpsU6VPLdctXi9Mam7Dg7 8wHjr9TPeWYZcmsbJ3vGHc8= X-Google-Smtp-Source: APXvYqwU4/DVNbkTmtnqe8ID5gcRDvzUyFSmU27AxR/5Rn0fKwz6WzjVz3H4yF0JlbbxHy1Ux6FnTg== X-Received: by 2002:a7b:cb04:: with SMTP id u4mr1543916wmj.0.1554285521985; Wed, 03 Apr 2019 02:58:41 -0700 (PDT) Received: from [192.168.1.22] ([94.230.156.24]) by smtp.gmail.com with ESMTPSA id b204sm28226478wmh.29.2019.04.03.02.58.41 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Wed, 03 Apr 2019 02:58:41 -0700 (PDT) Subject: Re: [PATCH net-next 06/17] net: dsa: Call driver's setup callback after setting up its switchdev notifier To: Andrew Lunn Cc: f.fainelli@gmail.com, vivien.didelot@gmail.com, davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linus.walleij@linaro.org, georg.waibel@sensor-technik.de References: <20190331174232.22060-1-olteanv@gmail.com> <20190331174232.22060-7-olteanv@gmail.com> <20190402210349.GG22349@lunn.ch> From: Vladimir Oltean Message-ID: <75b2250e-d6a5-44cb-42af-1d5838a03863@gmail.com> Date: Wed, 3 Apr 2019 12:58:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.3 MIME-Version: 1.0 In-Reply-To: <20190402210349.GG22349@lunn.ch> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 4/3/19 12:03 AM, Andrew Lunn wrote: > On Sun, Mar 31, 2019 at 08:42:21PM +0300, Vladimir Oltean wrote: >> This allows the driver to perform some manipulations of its own during >> setup, using generic code. >> One current usage scenario is for the driver to request DSA to set up >> 802.1Q based switch tagging for its ports. >> >> Signed-off-by: Vladimir Oltean >> Reviewed-by: Florian Fainelli >> --- >> net/dsa/dsa2.c | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c >> index c00ee464afc7..5beceb18b7e2 100644 >> --- a/net/dsa/dsa2.c >> +++ b/net/dsa/dsa2.c >> @@ -360,14 +360,14 @@ static int dsa_switch_setup(struct dsa_switch *ds) >> if (err) >> return err; >> >> - err = ds->ops->setup(ds); >> - if (err < 0) >> - return err; >> - >> err = dsa_switch_register_notifier(ds); >> if (err) >> return err; > > It seems that notifiers are the important thing here? Maybe state that > in the commit message? > > I'm also wondering how safe this is in general. If we have not yet > called the driver setup, the switch is potentially not yet ready to > actually handle an requests that come via the notifier. If such > notifiers can only come from the driver itself, it should be > safe. However, if they could come from the rest of the stack, i could > see bad things happening. > > Andrew > Hi Andrew, Correct me if I'm wrong, but the switchdev notifiers coming from the stack are coming through a net device, and the slave net devices are only created in dsa_port_setup, which is later than the code I'm modifying anyway? Do you have an example of potentially racy situation caused by this change? Thanks, -Vladimir