From patchwork Tue Sep 15 14:13:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 263812 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=-12.7 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=unavailable 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 A1A84C43461 for ; Wed, 16 Sep 2020 00:24:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 61DA5206A4 for ; Wed, 16 Sep 2020 00:24:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600215874; bh=Dz3z0d97SlQA4zKA/Bynm64n63535f8ww6CFV3dTdAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=R0lXVyRxiVwy2PlnwQOh9gT3AOnA4+sQrkPM88QbAGKjQSZhnTqxlsSXrWhllyUnX UgDNiwQHp1fwJxEbI5Fa3r1sQvydDQ+yb7af+bK7L22+h+0fAyxcTpLiHUL34fz0q9 XRm+X/KntlwdRc6ftof0SlD1YYM30thL3M3mJdto= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726734AbgIPAYb (ORCPT ); Tue, 15 Sep 2020 20:24:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:60630 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726742AbgIOOTx (ORCPT ); Tue, 15 Sep 2020 10:19:53 -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 6550E2222B; Tue, 15 Sep 2020 14:16:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179386; bh=Dz3z0d97SlQA4zKA/Bynm64n63535f8ww6CFV3dTdAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cD4f/N/68sJwTLIbwA+fks+ERMJSHD5JN+PwHD3BSeaGC+/pNK3NfI0xYQI+gTdNI uTkwUkzx5ws3wLXyexsYxgaZFmAhWxOpANNrjPc14M8BefVElFl6aoce1KHhTjHsEQ nTDq3M45QwZKKgUOioO18cCm3qtnPmztDCitHVlA= 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 4.19 40/78] iio: adc: mcp3422: fix locking scope Date: Tue, 15 Sep 2020 16:13:05 +0200 Message-Id: <20200915140635.594299228@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140633.552502750@linuxfoundation.org> References: <20200915140633.552502750@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org 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; @@ -155,7 +153,11 @@ 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,