From patchwork Tue Jun 28 15:16:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudiu Beznea X-Patchwork-Id: 12898439 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCA1AC433EF for ; Tue, 28 Jun 2022 15:14:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346166AbiF1PO0 (ORCPT ); Tue, 28 Jun 2022 11:14:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347648AbiF1POY (ORCPT ); Tue, 28 Jun 2022 11:14:24 -0400 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 940E92D1CE; Tue, 28 Jun 2022 08:14:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1656429263; x=1687965263; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=q7FahIoKfYcG6zpF9uJ/ng+YHB8nrWgCQyPp3cp9kiw=; b=H1ZZ+AtEqQq46RlOFH4t/z9YW+O9UdvQk5Tt2ejzU422aJRFqgvsShiv FRSrwc8ip//n6dBAPT9PYHQK4P9EJbjpvAl4+6hzFPcgoUndlnL+55jGh 3H/+73rsWaj/zeqN5xEh/O0syeb1o1JFysk1Nqo5dc6ne53pCXHV7SB7/ 8C+A4NOpIG5lLsBMk0lzrk+aHIsPxZTienWzyAGlvU7dSTZ3OuYa/HMg1 3GOvfUiDivDDtWvHIIVRMbBi36vssF11mDVVDAzOWIerCknZ2iPOwvGo2 ezGW6AAJl1mIWqmwYmXDfhBDHTdAKl5j6WGFE562sYqp9dgTXt+W/CZnI g==; X-IronPort-AV: E=Sophos;i="5.92,229,1650956400"; d="scan'208";a="165465254" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa2.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 28 Jun 2022 08:14:23 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.17; Tue, 28 Jun 2022 08:14:22 -0700 Received: from localhost.localdomain (10.10.115.15) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.2375.17 via Frontend Transport; Tue, 28 Jun 2022 08:14:19 -0700 From: Claudiu Beznea To: , , , , , , , CC: , , , Subject: [PATCH v2 03/19] iio: adc: at91-sama5d2_adc: lock around oversampling and sample freq Date: Tue, 28 Jun 2022 18:16:15 +0300 Message-ID: <20220628151631.3116454-4-claudiu.beznea@microchip.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20220628151631.3116454-1-claudiu.beznea@microchip.com> References: <20220628151631.3116454-1-claudiu.beznea@microchip.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org .read_raw()/.write_raw() could be called asynchronously from user space or other in kernel drivers. Without locking on st->lock these could be called asynchronously while there is a conversion in progress. Read will be harmless but changing registers while conversion is in progress may lead to inconsistent results. Thus, to avoid this lock st->lock. Fixes: 27e177190891 ("iio:adc:at91_adc8xx: introduce new atmel adc driver") Fixes: 6794e23fa3fe ("iio: adc: at91-sama5d2_adc: add support for oversampling resolution") Signed-off-by: Claudiu Beznea --- drivers/iio/adc/at91-sama5d2_adc.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c index c3301c749164..40a95d2fd5c8 100644 --- a/drivers/iio/adc/at91-sama5d2_adc.c +++ b/drivers/iio/adc/at91-sama5d2_adc.c @@ -1542,10 +1542,10 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev, ret = at91_adc_read_position(st, chan->channel, &tmp_val); *val = tmp_val; - mutex_unlock(&st->lock); - iio_device_release_direct_mode(indio_dev); if (ret > 0) ret = at91_adc_adjust_val_osr(st, val); + mutex_unlock(&st->lock); + iio_device_release_direct_mode(indio_dev); return ret; } @@ -1558,10 +1558,10 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev, ret = at91_adc_read_pressure(st, chan->channel, &tmp_val); *val = tmp_val; - mutex_unlock(&st->lock); - iio_device_release_direct_mode(indio_dev); if (ret > 0) ret = at91_adc_adjust_val_osr(st, val); + mutex_unlock(&st->lock); + iio_device_release_direct_mode(indio_dev); return ret; } @@ -1650,16 +1650,20 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev, /* if no change, optimize out */ if (val == st->oversampling_ratio) return 0; + mutex_lock(&st->lock); st->oversampling_ratio = val; /* update ratio */ at91_adc_config_emr(st); + mutex_unlock(&st->lock); return 0; case IIO_CHAN_INFO_SAMP_FREQ: if (val < st->soc_info.min_sample_rate || val > st->soc_info.max_sample_rate) return -EINVAL; + mutex_lock(&st->lock); at91_adc_setup_samp_freq(indio_dev, val); + mutex_unlock(&st->lock); return 0; default: return -EINVAL;