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=-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 79BDEC43466 for ; Mon, 21 Sep 2020 16:33:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 40C2023A03 for ; Mon, 21 Sep 2020 16:33:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600705990; bh=D6ioDQNlnawCrx2GcOF/N/wwukoyQL0N+drj/kH08Bs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SV6mcpseA/H5pjTYmj3ElSm3R3QrDUaKV8ThE4H4ojOm+YrxUKngKtb3nh46aHaQ4 uJLdPEsyY5/RuPvfBDvnBBpz41ckKUdoiQ6tj84s+qO2Pvty0BBrAlWtnfwl/L5hFE PvsdKovd9bVGUPwliHLJ/5+cvQyOq+oF/xInyko0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728579AbgIUQdI (ORCPT ); Mon, 21 Sep 2020 12:33:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:58924 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728561AbgIUQdB (ORCPT ); Mon, 21 Sep 2020 12:33:01 -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 AB110239D0; Mon, 21 Sep 2020 16:33:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600705981; bh=D6ioDQNlnawCrx2GcOF/N/wwukoyQL0N+drj/kH08Bs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V+aCAq4unyKq4VxOjFi39ixKmidyfib1zM3Yhfvzx0UkylNzLfSATiTkE0U/dcOQA aWQoIm4cMUeP4yrgf5fZFNhhESYcjgpBuqc9gNmA/ANThLRpYsXtj5Lpk5v5c3YsNX Gzp3kNcs6N5s6v5zDFRQz85NmMgqqr2QCj3dTHBQ= 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 4.4 10/46] iio: adc: mcp3422: fix locking scope Date: Mon, 21 Sep 2020 18:27:26 +0200 Message-Id: <20200921162033.840827318@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162033.346434578@linuxfoundation.org> References: <20200921162033.346434578@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 @@ -98,16 +98,12 @@ 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; } @@ -140,6 +136,8 @@ 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; @@ -152,7 +150,11 @@ 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,