From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F2362628D; Fri, 1 Aug 2025 13:15:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754054122; cv=none; b=VJtW2iqtfmxapyzkVVucq8hJ2f70KzM437H/mZX1jDP7PI0TNiPcFB5c9I3XaUshRwxUbnUOBfOPFq8902mwfgDDdykUvUSCsrUXNzE1Zj4O0tcvJlMbWSqI9IwvVV20IYNwO2gfiy1BR2vPI1Ma1/jHcB7b0OPE4FxmRH6nviQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754054122; c=relaxed/simple; bh=KpY+pHTlEqtqKPX++6/jobAXDKvdILMuJ5/p/I4i5n0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=d0oa8F168fjo1fsdO5upFjSnmAmVeEKM2KrReTVJbFfirWkq1oUOVS6RZuhtfl5nKaeSQaOVchRTR/+E7tafSaKT2dPoMsn3/DQggOW3VcMDqxaJ+Fv+LN+L2txFk3vdXjZaMMD+99rXKhVMp7e4iAKkUpM28g024hivv4RdDGY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=goBBN0+C; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="goBBN0+C" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To: Content-Transfer-Encoding:Content-Type: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-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Kad9jR19PDpT1ZcaPhylvlERiT+jB6wY6uHs03XcUFA=; b=goBBN0+CfNCrvTuDwuvuVQJM/z uGPmZwn0XR4bv6YmSUS+73iloqSjMUegnZqe8xyTrVUIhdP6lMGkSqf+BAPQcXir5Jbx7qAr/aO1W TxgWjm/yFITBN8fbzdZ1e+Zoktoq3i/JAR3jOMS5zZub+5yyBdLnqXP5KqB+cJ6FN1jwb+Tbs3X0v OofLtY6MaU7ABSdxm3fQNsrTuNdVUUi4qfmQvcxAc6PgSYzOHs7m3Jwo1aXFNOSDkUhsr7trxyYJz VKVtHHZTeDd7yiozVAh74qzw+d4bTSgfKD+/U1aHcof4z78NCPH5hudMz5sych2k9ZjrWVjTb/eGK TIcYEzrw==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:43298) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uhpbJ-0006YZ-28; Fri, 01 Aug 2025 14:15:09 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.96) (envelope-from ) id 1uhpbG-00026a-0a; Fri, 01 Aug 2025 14:15:06 +0100 Date: Fri, 1 Aug 2025 14:15:06 +0100 From: "Russell King (Oracle)" To: =?iso-8859-1?B?Q3Pza+Fz?= Bence Cc: Geert Uytterhoeven , Mark Brown , Sergei Shtylyov , "David S. Miller" , Rob Herring , Andrew Lunn , Andy Shevchenko , Dmitry Torokhov , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Csaba Buday , Heiner Kallweit , Eric Dumazet , Jakub Kicinski , Paolo Abeni Subject: Re: [PATCH net] net: mdio_bus: Use devm for getting reset GPIO Message-ID: References: <20250728153455.47190-2-csokas.bence@prolan.hu> <95449490-fa58-41d4-9493-c9213c1f2e7d@sirena.org.uk> <86bb6477-56d9-415a-a0ad-9a5d963a285e@prolan.hu> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <86bb6477-56d9-415a-a0ad-9a5d963a285e@prolan.hu> Sender: Russell King (Oracle) On Fri, Aug 01, 2025 at 03:04:31PM +0200, Csókás Bence wrote: > Hi, > > On 2025. 08. 01. 14:33, Russell King (Oracle) wrote: > > On Fri, Aug 01, 2025 at 02:25:17PM +0200, Geert Uytterhoeven wrote: > > > Hi Mark, > > > > > > On Fri, 1 Aug 2025 at 14:01, Mark Brown wrote: > > > > On Mon, Jul 28, 2025 at 05:34:55PM +0200, Bence Csókás wrote: > > > > > Commit bafbdd527d56 ("phylib: Add device reset GPIO support") removed > > > > > devm_gpiod_get_optional() in favor of the non-devres managed > > > > > fwnode_get_named_gpiod(). When it was kind-of reverted by commit > > > > > 40ba6a12a548 ("net: mdio: switch to using gpiod_get_optional()"), the devm > > > > > functionality was not reinstated. Nor was the GPIO unclaimed on device > > > > > remove. This leads to the GPIO being claimed indefinitely, even when the > > > > > device and/or the driver gets removed. > > > > > > > > I'm seeing multiple platforms including at least Beaglebone Black, > > > > Tordax Mallow and Libre Computer Alta printing errors in > > > > next/pending-fixes today: > > > > > > > > [ 3.252885] mdio_bus 4a101000.mdio:00: Resources present before probing > > > > > > > > Bisects are pointing to this patch which is 3b98c9352511db in -next, > > > > > > My guess is that &mdiodev->dev is not the correct device for > > > resource management. > > > > No, looking at the patch, the patch is completely wrong. > > > > Take for example mdiobus_register_gpiod(). Using devm_*() there is > > completely wrong, because this is called from mdiobus_register_device(). > > This is not the probe function for the device, and thus there is no > > code to trigger the release of the resource on unregistration. > > > > Moreover, when the mdiodev is eventually probed, if the driver fails > > or the driver is unbound, the GPIO will be released, but a reference > > will be left behind. > > > > Using devm* with a struct device that is *not* currently being probed > > is fundamentally wrong - an abuse of devm. > > The real question is: why on Earth is mdiobus_register_device() called > _before_ the probe()? Please review the code and *understand* it before making changes. This is what any experienced programmer will do, so please get into that habbit - it'll help you not to get a bad name in the kernel community. If you don't understand that mdiobus_register_device() would be called outside of the device's probe function, then you need to gain that knowledge through research. Please treat this as a learning exercise. First step: grep -r mdiobus_register_device drivers/net/phy Thanks. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!