From patchwork Mon Sep 28 13:13:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mircea Caprioru X-Patchwork-Id: 11803825 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 49723618 for ; Mon, 28 Sep 2020 13:14:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 338A82076D for ; Mon, 28 Sep 2020 13:14:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726765AbgI1NOZ (ORCPT ); Mon, 28 Sep 2020 09:14:25 -0400 Received: from mx0a-00128a01.pphosted.com ([148.163.135.77]:24990 "EHLO mx0a-00128a01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726506AbgI1NOV (ORCPT ); Mon, 28 Sep 2020 09:14:21 -0400 Received: from pps.filterd (m0167089.ppops.net [127.0.0.1]) by mx0a-00128a01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08SD7QBg001014; Mon, 28 Sep 2020 09:14:08 -0400 Received: from nwd2mta4.analog.com ([137.71.173.58]) by mx0a-00128a01.pphosted.com with ESMTP id 33t2j4f81u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Sep 2020 09:14:08 -0400 Received: from ASHBMBX8.ad.analog.com (ASHBMBX8.ad.analog.com [10.64.17.5]) by nwd2mta4.analog.com (8.14.7/8.14.7) with ESMTP id 08SDE69h064524 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=FAIL); Mon, 28 Sep 2020 09:14:06 -0400 Received: from ASHBMBX9.ad.analog.com (10.64.17.10) by ASHBMBX8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Mon, 28 Sep 2020 09:14:00 -0400 Received: from zeus.spd.analog.com (10.66.68.11) by ASHBMBX9.ad.analog.com (10.64.17.10) with Microsoft SMTP Server id 15.1.1779.2 via Frontend Transport; Mon, 28 Sep 2020 09:14:00 -0400 Received: from localhost.localdomain ([10.48.65.12]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 08SDDuB6030926; Mon, 28 Sep 2020 09:14:02 -0400 From: Mircea Caprioru To: CC: , , , , , , Sergiu Cuciurean , Mircea Caprioru Subject: [PATCH 3/5] iio: adc: npcm_adc: Replace indio_dev->mlock with own device lock Date: Mon, 28 Sep 2020 16:13:31 +0300 Message-ID: <20200928131333.36646-3-mircea.caprioru@analog.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200928131333.36646-1-mircea.caprioru@analog.com> References: <20200928131333.36646-1-mircea.caprioru@analog.com> MIME-Version: 1.0 X-ADIRoutedOnPrem: True X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-28_11:2020-09-28,2020-09-28 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 suspectscore=0 priorityscore=1501 phishscore=0 spamscore=0 malwarescore=0 bulkscore=0 clxscore=1015 mlxlogscore=742 mlxscore=0 adultscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009280104 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org From: Sergiu Cuciurean As part of the general cleanup of indio_dev->mlock, this change replaces it with a local lock on the device's state structure. This is part of a bigger cleanup. Link: https://lore.kernel.org/linux-iio/CA+U=Dsoo6YABe5ODLp+eFNPGFDjk5ZeQEceGkqjxXcVEhLWubw@mail.gmail.com/ Signed-off-by: Sergiu Cuciurean Signed-off-by: Mircea Caprioru --- drivers/iio/adc/npcm_adc.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/npcm_adc.c b/drivers/iio/adc/npcm_adc.c index d9d105920001..f7bc0bb7f112 100644 --- a/drivers/iio/adc/npcm_adc.c +++ b/drivers/iio/adc/npcm_adc.c @@ -25,6 +25,15 @@ struct npcm_adc { wait_queue_head_t wq; struct regulator *vref; struct reset_control *reset; + /* + * Lock to protect the device state during a potential concurrent + * read access from userspace. Reading a raw value requires a sequence + * of register writes, then a wait for a event and finally a register + * read, during which userspace could issue another read request. + * This lock protects a read access from ocurring before another one + * has finished. + */ + struct mutex lock; }; /* ADC registers */ @@ -135,9 +144,9 @@ static int npcm_adc_read_raw(struct iio_dev *indio_dev, switch (mask) { case IIO_CHAN_INFO_RAW: - mutex_lock(&indio_dev->mlock); + mutex_lock(&info->lock); ret = npcm_adc_read(info, val, chan->channel); - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); if (ret) { dev_err(info->dev, "NPCM ADC read failed\n"); return ret; @@ -187,6 +196,8 @@ static int npcm_adc_probe(struct platform_device *pdev) return -ENOMEM; info = iio_priv(indio_dev); + mutex_init(&info->lock); + info->dev = &pdev->dev; info->regs = devm_platform_ioremap_resource(pdev, 0);