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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 0996EC433F5 for ; Mon, 6 Sep 2021 08:30:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBAF260555 for ; Mon, 6 Sep 2021 08:30:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240682AbhIFIbP (ORCPT ); Mon, 6 Sep 2021 04:31:15 -0400 Received: from mga17.intel.com ([192.55.52.151]:16828 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240675AbhIFIbN (ORCPT ); Mon, 6 Sep 2021 04:31:13 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10098"; a="200127585" X-IronPort-AV: E=Sophos;i="5.85,271,1624345200"; d="scan'208";a="200127585" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Sep 2021 01:30:07 -0700 X-IronPort-AV: E=Sophos;i="5.85,271,1624345200"; d="scan'208";a="546120504" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Sep 2021 01:30:06 -0700 Received: from andy by smile with local (Exim 4.95-RC2) (envelope-from ) id 1mNA0y-000Ros-2H; Mon, 06 Sep 2021 11:30:04 +0300 Date: Mon, 6 Sep 2021 11:30:04 +0300 From: Andy Shevchenko To: Heiner Kallweit Cc: Jean Delvare , "linux-i2c@vger.kernel.org" Subject: Re: [PATCH] i2c: i801: Use PCI bus rescan mutex to protect P2SB access Message-ID: References: <7521c130-d777-6a26-bd14-1ed784f828cc@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7521c130-d777-6a26-bd14-1ed784f828cc@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On Sun, Sep 05, 2021 at 05:59:42PM +0200, Heiner Kallweit wrote: > As pointed out by Andy in [0] using a local mutex here isn't strictly > wrong but not sufficient. We should hold the PCI rescan lock for P2SB > operations. Thanks! Reviewed-by: Andy Shevchenko > [0] https://www.spinics.net/lists/linux-i2c/msg52717.html > > Fixes: 1a987c69ce2c ("i2c: i801: make p2sb_spinlock a mutex") > Reported-by: Andy Shevchenko > Signed-off-by: Heiner Kallweit > --- > drivers/i2c/busses/i2c-i801.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c > index 89ae78ef1..1f929e6c3 100644 > --- a/drivers/i2c/busses/i2c-i801.c > +++ b/drivers/i2c/busses/i2c-i801.c > @@ -1493,7 +1493,6 @@ static struct platform_device * > i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev, > struct resource *tco_res) > { > - static DEFINE_MUTEX(p2sb_mutex); > struct resource *res; > unsigned int devfn; > u64 base64_addr; > @@ -1506,7 +1505,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev, > * enumerated by the PCI subsystem, so we need to unhide/hide it > * to lookup the P2SB BAR. > */ > - mutex_lock(&p2sb_mutex); > + pci_lock_rescan_remove(); > > devfn = PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 1); > > @@ -1524,7 +1523,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev, > /* Hide the P2SB device, if it was hidden before */ > if (hidden) > pci_bus_write_config_byte(pci_dev->bus, devfn, 0xe1, hidden); > - mutex_unlock(&p2sb_mutex); > + pci_unlock_rescan_remove(); > > res = &tco_res[1]; > if (pci_dev->device == PCI_DEVICE_ID_INTEL_DNV_SMBUS) > -- > 2.33.0 > -- With Best Regards, Andy Shevchenko