From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753295AbaLNOGQ (ORCPT ); Sun, 14 Dec 2014 09:06:16 -0500 Received: from a.ns.miles-group.at ([95.130.255.143]:65275 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750789AbaLNOGO (ORCPT ); Sun, 14 Dec 2014 09:06:14 -0500 Message-ID: <548D9951.1070003@nod.at> Date: Sun, 14 Dec 2014 15:06:09 +0100 From: Richard Weinberger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.0 MIME-Version: 1.0 To: Hartmut Knaack , jic23@kernel.org CC: harald@ccbib.org, lars@metafoo.de, pmeerw@pmeerw.net, sanjeev_sharma@mentor.com, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] iio: dht11: Add locking References: <1417563176-31972-1-git-send-email-richard@nod.at> <1417563176-31972-2-git-send-email-richard@nod.at> <548D8317.2070405@gmx.de> In-Reply-To: <548D8317.2070405@gmx.de> Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 14.12.2014 um 13:31 schrieb Hartmut Knaack: > Richard Weinberger schrieb am 03.12.2014 um 00:32: >> Make sure that the read function is not interrupted... > There is already a mutex iio_dev->info_exist_lock used to serialize > iio_channel_read(), which in turn accesses _read_raw(). See [1]. > > [1]http://lxr.free-electrons.com/ident?i=iio_channel_read This is only for the in-kernel API and not for sysfs access. I.e. if you access via sysfs it is not protected. Thanks, //richard >> Signed-off-by: Richard Weinberger >> --- >> drivers/iio/humidity/dht11.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c >> index d8771f5..168ebc4 100644 >> --- a/drivers/iio/humidity/dht11.c >> +++ b/drivers/iio/humidity/dht11.c >> @@ -29,6 +29,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -57,6 +58,7 @@ struct dht11 { >> int irq; >> >> struct completion completion; >> + struct mutex lock; >> >> s64 timestamp; >> int temperature; >> @@ -145,6 +147,7 @@ static int dht11_read_raw(struct iio_dev *iio_dev, >> struct dht11 *dht11 = iio_priv(iio_dev); >> int ret; >> >> + mutex_lock(&dht11->lock); >> if (dht11->timestamp + DHT11_DATA_VALID_TIME < iio_get_time_ns()) { >> reinit_completion(&dht11->completion); >> >> @@ -185,6 +188,7 @@ static int dht11_read_raw(struct iio_dev *iio_dev, >> ret = -EINVAL; >> err: >> dht11->num_edges = -1; >> + mutex_unlock(&dht11->lock); >> return ret; >> } >> >> @@ -268,6 +272,7 @@ static int dht11_probe(struct platform_device *pdev) >> platform_set_drvdata(pdev, iio); >> >> init_completion(&dht11->completion); >> + mutex_init(&dht11->lock); >> iio->name = pdev->name; >> iio->dev.parent = &pdev->dev; >> iio->info = &dht11_iio_info; >> >