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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 B2EE8C43441 for ; Fri, 23 Nov 2018 15:08:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7698920824 for ; Fri, 23 Nov 2018 15:08:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="23VDG7MR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7698920824 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lunn.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2504810AbeKXBwp (ORCPT ); Fri, 23 Nov 2018 20:52:45 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:47014 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2504792AbeKXBwo (ORCPT ); Fri, 23 Nov 2018 20:52:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=+g2W/obI3cWbottSoUi5ycyOnVZOBTkOEsXK/8dB/vk=; b=23VDG7MRE+bBBThhLbaWS5TlCtZ0p/Pa+BhoEMUDgJcv8tO9o8slbINt/KkqpeKogaEb1XLgD+7WPaDP1dQa6IiZImfDT3aKD9EpqRYbwKHVtNHRAhnroK+SHqmAfgRaJSyuD0lPQAhcaL5KGK0OGYNqyEI1eGEsXHkjG1qOWCs=; Received: from andrew by vps0.lunn.ch with local (Exim 4.84_2) (envelope-from ) id 1gQD3u-00089i-MK; Fri, 23 Nov 2018 16:08:06 +0100 Date: Fri, 23 Nov 2018 16:08:06 +0100 From: Andrew Lunn To: Quentin Schulz Cc: davem@davemloft.net, f.fainelli@gmail.com, allan.nielsen@microchip.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, thomas.petazzoni@bootlin.com, alexandre.belloni@bootlin.com Subject: Re: [PATCH net v2] net: phy: mscc: fix deadlock in vsc85xx_default_config Message-ID: <20181123150806.GB30913@lunn.ch> References: <20181123081636.18795-1-quentin.schulz@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181123081636.18795-1-quentin.schulz@bootlin.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 23, 2018 at 09:16:36AM +0100, Quentin Schulz wrote: > The vsc85xx_default_config function called in the vsc85xx_config_init > function which is used by VSC8530, VSC8531, VSC8540 and VSC8541 PHYs > mistakenly calls phy_read and phy_write in-between phy_select_page and > phy_restore_page. > > phy_select_page and phy_restore_page actually take and release the MDIO > bus lock and phy_write and phy_read take and release the lock to write > or read to a PHY register. > > Let's fix this deadlock by using phy_modify_paged which handles > correctly a read followed by a write in a non-standard page. > > Fixes: 6a0bfbbe20b0 ("net: phy: mscc: migrate to phy_select/restore_page functions") > > Signed-off-by: Quentin Schulz > --- > > v2: > - use phy_modify_paged instead of > phy_select_page -> __phy_read -> __phy_write -> phy_restore_page > > drivers/net/phy/mscc.c | 13 ++++++------- > 1 file changed, 6 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/phy/mscc.c b/drivers/net/phy/mscc.c > index 62269e578718..4dcf7ad06259 100644 > --- a/drivers/net/phy/mscc.c > +++ b/drivers/net/phy/mscc.c > @@ -810,17 +810,16 @@ static int vsc85xx_default_config(struct phy_device *phydev) > > phydev->mdix_ctrl = ETH_TP_MDI_AUTO; > mutex_lock(&phydev->lock); > - rc = phy_select_page(phydev, MSCC_PHY_PAGE_EXTENDED_2); > + > + reg_val = RGMII_RX_CLK_DELAY_1_1_NS << RGMII_RX_CLK_DELAY_POS; > + > + rc = phy_modify_paged(phydev, MSCC_PHY_PAGE_EXTENDED_2, > + MSCC_PHY_RGMII_CNTL, RGMII_RX_CLK_DELAY_MASK, > + reg_val); > if (rc < 0) > goto out_unlock; Hi Quentin Isn't this goto now pointless. You are not jumping over anything. Andrew > > - reg_val = phy_read(phydev, MSCC_PHY_RGMII_CNTL); > - reg_val &= ~(RGMII_RX_CLK_DELAY_MASK); > - reg_val |= (RGMII_RX_CLK_DELAY_1_1_NS << RGMII_RX_CLK_DELAY_POS); > - phy_write(phydev, MSCC_PHY_RGMII_CNTL, reg_val); > - > out_unlock: > - rc = phy_restore_page(phydev, rc, rc > 0 ? 0 : rc); > mutex_unlock(&phydev->lock); > > return rc; > -- > 2.17.1 >