From patchwork Mon Sep 21 16:27:15 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: 263750 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 DD0D1C4346A for ; Mon, 21 Sep 2020 16:34:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A70E9239D0 for ; Mon, 21 Sep 2020 16:34:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706046; bh=UQ9uhk9yESmpsuclrVoey/brZ5TMAsHuztHElWFK4Kc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=J4+vXYeW2Tw+zDLx2uk04GbZg7sf4xC22CoAjKzx0aP/9KSUhMp+yRZwrrwOI5bF6 cAlXtephf5Sab3+WcuqQhc3JgFwNY8MPJNVUWE+XkOCQMtBQDR5GMGPfa3Ju/zyfKu /+wxvOPpdXt1SNA0aGILZNbWQr+1ljf1j8RjrNDo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728701AbgIUQeF (ORCPT ); Mon, 21 Sep 2020 12:34:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:60448 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728674AbgIUQd5 (ORCPT ); Mon, 21 Sep 2020 12:33:57 -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 3C9CA23976; Mon, 21 Sep 2020 16:33:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600706036; bh=UQ9uhk9yESmpsuclrVoey/brZ5TMAsHuztHElWFK4Kc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J5GdkIkZoA/5J+wUyykNv++OWvFVHVTz7HsB01a7ToUiDr7XuBHBAnuWRdQJz3/eW Rap4zl3EYb6PQaWvsYENqTcG8f4XMFmVlWwHq5fsKV0cuuXuYWnobjW6YiXeJkIN0W hIAX3I5+ZQ1igYvbjZBR+mfUEDDOnzLhql1Q8Yuc= 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 4.9 15/70] iio: adc: mcp3422: fix locking scope Date: Mon, 21 Sep 2020 18:27:15 +0200 Message-Id: <20200921162035.825651264@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162035.136047591@linuxfoundation.org> References: <20200921162035.136047591@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,