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[23.128.96.18]) by mx.google.com with ESMTP id p8si3850742edj.482.2021.09.02.12.07.28; Thu, 02 Sep 2021 12:07:55 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b="EF/FsMDX"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347254AbhIBTGK (ORCPT + 99 others); Thu, 2 Sep 2021 15:06:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347090AbhIBTGJ (ORCPT ); Thu, 2 Sep 2021 15:06:09 -0400 Received: from mail-ed1-x529.google.com (mail-ed1-x529.google.com [IPv6:2a00:1450:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4AED8C061575; Thu, 2 Sep 2021 12:05:10 -0700 (PDT) Received: by mail-ed1-x529.google.com with SMTP id q17so4471150edv.2; Thu, 02 Sep 2021 12:05:10 -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=F3V7EjM9yRS05v9IOxp0t6fq7hXaIjKJDbM8wh8rkpk=; b=EF/FsMDX4vrswrhLo9RSoWV7HVr/ZuqCV/v0uXSO4x2FsIxogZq5BuPlR+fsgfohcH zI0QY9+Dt2Pif4GIio7YUYPjwq0IzvxcH4KX75/77YnDRCOygKHqN3GAc2qtWAcAAwfG zTgIys+QTvqR2qSOb7PG8M4ZZok4O45gV6JIRiCGCG0xhdJ3v9AEK6uB36cICO/IXyky m759QMzjFOH/t81EWzu0meQM0wCKpNTV8lSasgcJ1DE0agc0hpifYPSeo9sf7QQ7axQA 5VWPoQ4LtoVhTx+yVrNHp2RkYQ1WTfZuLL4GWWLqY+yGDYy321Qvv/UFbQtNLe/sLB69 TmXA== 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=F3V7EjM9yRS05v9IOxp0t6fq7hXaIjKJDbM8wh8rkpk=; b=bw+XrO+WlTvznO8xueA4U28srzpnhJ2ILPeZD0P378wfkr2st+oJOMn4TD3IR9OVuJ Y9Tuz0DkUZyYcqqnbR8TLkFvj0DgyrdE4X/Ed9pG53/NB6OsDngpYxE/dyxa3Q/KONo/ 5ScTKnxwOGFS+E3aq2QwjQhYXVY9CsEdXJ2g0zm3l4MtHqC4NmKjOXl1olVTKbwDQg/z uXxOinl+6T3woh0Ja3qmMTCfFpfgFN9a8IMRMuB0zdu+uuGr5FLok6xOxE7dOpQJf/CZ Pb5nxtIYMTXsBGVR3hTaR0qRgmNC+g+ExadsZvpyEY8pKjo5odbyVaznlnPUVqXi0kCT cT4Q== X-Gm-Message-State: AOAM533+2FjBh5YJ7HZ/P+jC/HawG3z8Ao+cx/tLZzcyDQfMUPRHA1nI PBKE7nGVEUj6xOWVgWWJaRg= X-Received: by 2002:aa7:d986:: with SMTP id u6mr5083172eds.156.1630609508814; Thu, 02 Sep 2021 12:05:08 -0700 (PDT) Received: from skbuf ([82.78.148.104]) by smtp.gmail.com with ESMTPSA id b2sm1574735ejj.124.2021.09.02.12.05.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Sep 2021 12:05:08 -0700 (PDT) Date: Thu, 2 Sep 2021 22:05:07 +0300 From: Vladimir Oltean To: "Russell King (Oracle)" Cc: Vladimir Oltean , "netdev@vger.kernel.org" , Greg Kroah-Hartman , "Rafael J. Wysocki" , Andrew Lunn , Heiner Kallweit , "David S. Miller" , Jakub Kicinski , Vivien Didelot , Florian Fainelli , "linux-kernel@vger.kernel.org" , Linus Walleij , Alvin =?utf-8?Q?=C5=A0ipraga?= , ACPI Devel Maling List , kernel-team , Len Brown Subject: Re: [RFC PATCH net-next 0/3] Make the PHY library stop being so greedy when binding the generic PHY driver Message-ID: <20210902190507.shcdmfi3v55l2zuj@skbuf> References: <20210901225053.1205571-1-vladimir.oltean@nxp.com> <20210902121927.GE22278@shell.armlinux.org.uk> <20210902123532.ruvuecxoig67yv5v@skbuf> <20210902132635.GG22278@shell.armlinux.org.uk> <20210902152342.vett7qfhvhiyejvo@skbuf> <20210902163144.GH22278@shell.armlinux.org.uk> <20210902171033.4byfnu3g25ptnghg@skbuf> <20210902175043.GK22278@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210902175043.GK22278@shell.armlinux.org.uk> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 02, 2021 at 06:50:43PM +0100, Russell King (Oracle) wrote: > On Thu, Sep 02, 2021 at 05:10:34PM +0000, Vladimir Oltean wrote: > > On Thu, Sep 02, 2021 at 05:31:44PM +0100, Russell King (Oracle) wrote: > > > On Thu, Sep 02, 2021 at 06:23:42PM +0300, Vladimir Oltean wrote: > > > > On Thu, Sep 02, 2021 at 02:26:35PM +0100, Russell King (Oracle) wrote: > > > > > Debian has had support for configuring bridges at boot time via > > > > > the interfaces file for years. Breaking that is going to upset a > > > > > lot of people (me included) resulting in busted networks. It > > > > > would be a sure way to make oneself unpopular. > > > > > > > > > > > I expect there to be 2 call paths of phy_attach_direct: > > > > > > - At probe time. Both the MAC driver and the PHY driver are probing. > > > > > > This is what has this patch addresses. There is no issue to return > > > > > > -EPROBE_DEFER at that time, since drivers connect to the PHY before > > > > > > they register their netdev. So if connecting defers, there is no > > > > > > netdev to unregister, and user space knows nothing of this. > > > > > > - At .ndo_open time. This is where it maybe gets interesting, but not to > > > > > > user space. If you open a netdev and it connects to the PHY then, I > > > > > > wouldn't expect the PHY to be undergoing a probing process, all of > > > > > > that should have been settled by then, should it not? Where it might > > > > > > get interesting is with NFS root, and I admit I haven't tested that. > > > > > > > > > > I don't think you can make that assumption. Consider the case where > > > > > systemd is being used, DSA stuff is modular, and we're trying to > > > > > setup a bridge device on DSA. DSA could be probing while the bridge > > > > > is being setup. > > > > > > > > > > Sadly, this isn't theoretical. I've ended up needing: > > > > > > > > > > pre-up sleep 1 > > > > > > > > > > in my bridge configuration to allow time for DSA to finish probing. > > > > > It's not a pleasant solution, nor a particularly reliable one at > > > > > that, but it currently works around the problem. > > > > > > > > What problem? This is the first time I've heard of this report, and you > > > > should definitely not need that. > > > > > > I found it when upgrading the Clearfog by the DSL modems to v5.13. > > > When I rebooted it with a previously working kernel (v5.7) it has > > > never had a problem. With v5.13, it failed to add all the lan ports > > > into the bridge, because the bridge was still being setup by the > > > kernel while userspace was trying to configure it. Note that I have > > > extra debug in my kernels, hence the extra messages: > > > > Ok, first you talked about the interfaces file, then systemd. If it's > > not about systemd's network manager then I don't see how it is relevant. > > You're reading in stuff to what I write that I did not write... I said: > > "Consider the case where systemd is being used, DSA stuff is modular, > and we're trying to setup a bridge device on DSA." > > That does not mean I'm using systemd's network manager - which is > something I know little about and have never used. You should definitely try it out, it gets a lot of new features added all the time, it uses the netlink interface, it reacts on udev events. > The reason I mentioned systemd is precisely because with systemd, you > get a hell of a lot happening parallel - and that's significiant in > this case, because it's very clear that modules are being loaded in > parallel with networking being brought up - and that is where the > problems begin. In fact, modules themselves get loaded in paralllel > with systemd. So that's what I don't understand. You're saying that the ifupdown service runs in parallel with systemd-modules-load.service, and networking is a kernel module? Doesn't that mean it behaves as expected, then? /shrug/ Have you tried adding an 'After=systemd-modules-load.service' dependency to the ifupdown service? I don't think that DSA is that bad that it registers its net devices outside of the process context in which the insmod mv88e6xxx.ko is called. Quite the opposite, I think (but I haven't actually taken a close look yet) that the component stuff Saravana is proposing would do exactly that. So you "fix" one issue, you introduce another.