From patchwork Mon Sep 21 16:27:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 309467 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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 2AF84C43469 for ; Mon, 21 Sep 2020 16:38:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E340823A03 for ; Mon, 21 Sep 2020 16:38:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706335; bh=UQ9uhk9yESmpsuclrVoey/brZ5TMAsHuztHElWFK4Kc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=HOXdJKMPZyazNNwVdgPWv7R0OaSk3rBgjSurGg4hJNm5hOHSrnSrnK5eUVoIwyupd FZ3210eN53qGOFdu6F3/Jpa0bJwoS0EGCXQ8jRuClx6Q1breM4QJx/fJoMC/sIZHzO ZiJkmxKfNvxk43M42U9ZiQtGerbnEC6cvwGduI/4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728654AbgIUQiy (ORCPT ); Mon, 21 Sep 2020 12:38:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:39786 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728614AbgIUQif (ORCPT ); Mon, 21 Sep 2020 12:38:35 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B64C7238EE; Mon, 21 Sep 2020 16:38:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706314; bh=UQ9uhk9yESmpsuclrVoey/brZ5TMAsHuztHElWFK4Kc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=egm473pQdXx8rPphpec9nEqSgB/ejkkxz93Zm93iBxSc5vwXw7+dwbwO5Q1QeBuD8 VFR7H56fTUIvnG9t09Vuyzr8lZZJcvSCYjenmug886OerIglJk9WBMb4rlgifHep+f +OGgY3B3kTadyLA9ZMmA08dDnZD8rfZaTsmBg+/E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Angelo Compagnucci , Stable@vger.kernel.org, Jonathan Cameron Subject: [PATCH 4.14 23/94] iio: adc: mcp3422: fix locking scope Date: Mon, 21 Sep 2020 18:27:10 +0200 Message-Id: <20200921162036.617304797@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162035.541285330@linuxfoundation.org> References: <20200921162035.541285330@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Angelo Compagnucci commit 3f1093d83d7164e4705e4232ccf76da54adfda85 upstream. Locking should be held for the entire reading sequence involving setting the channel, waiting for the channel switch and reading from the channel. If not, reading from a channel can result mixing with the reading from another channel. Fixes: 07914c84ba30 ("iio: adc: Add driver for Microchip MCP3422/3/4 high resolution ADC") Signed-off-by: Angelo Compagnucci Link: https://lore.kernel.org/r/20200819075525.1395248-1-angelo.compagnucci@gmail.com Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/adc/mcp3422.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/drivers/iio/adc/mcp3422.c +++ b/drivers/iio/adc/mcp3422.c @@ -99,16 +99,12 @@ static int mcp3422_update_config(struct { int ret; - mutex_lock(&adc->lock); - ret = i2c_master_send(adc->i2c, &newconfig, 1); if (ret > 0) { adc->config = newconfig; ret = 0; } - mutex_unlock(&adc->lock); - return ret; } @@ -141,6 +137,8 @@ static int mcp3422_read_channel(struct m u8 config; u8 req_channel = channel->channel; + mutex_lock(&adc->lock); + if (req_channel != MCP3422_CHANNEL(adc->config)) { config = adc->config; config &= ~MCP3422_CHANNEL_MASK; @@ -153,7 +151,11 @@ static int mcp3422_read_channel(struct m msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]); } - return mcp3422_read(adc, value, &config); + ret = mcp3422_read(adc, value, &config); + + mutex_unlock(&adc->lock); + + return ret; } static int mcp3422_read_raw(struct iio_dev *iio,