From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752844AbeDOTd3 (ORCPT ); Sun, 15 Apr 2018 15:33:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:52012 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752464AbeDOTd1 (ORCPT ); Sun, 15 Apr 2018 15:33:27 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E0DC82172D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=jic23@kernel.org Date: Sun, 15 Apr 2018 20:33:21 +0100 From: Jonathan Cameron To: Eugen Hristev Cc: , , , , , , , , , Subject: Re: [PATCH v3 06/11] iio: inkern: add module put/get on iio dev module when requesting channels Message-ID: <20180415203321.1aaaf91e@archlinux> In-Reply-To: <1523350677-27106-7-git-send-email-eugen.hristev@microchip.com> References: <1523350677-27106-1-git-send-email-eugen.hristev@microchip.com> <1523350677-27106-7-git-send-email-eugen.hristev@microchip.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 10 Apr 2018 11:57:52 +0300 Eugen Hristev wrote: > When requesting channels for a particular consumer device, > besides requesting the device (incrementing the reference counter), also > do it for the driver module of the iio dev. This will avoid the situation > where the producer IIO device can be removed and the consumer is still > present in the kernel. > > Signed-off-by: Eugen Hristev > --- > drivers/iio/inkern.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c > index ec98790..68d9b87 100644 > --- a/drivers/iio/inkern.c > +++ b/drivers/iio/inkern.c > @@ -11,6 +11,7 @@ > #include > #include > #include > +#include > > #include > #include "iio_core.h" > @@ -152,6 +153,7 @@ static int __of_iio_channel_get(struct iio_channel *channel, > if (index < 0) > goto err_put; > channel->channel = &indio_dev->channels[index]; > + try_module_get(channel->indio_dev->driver_module); And if it fails? (the module we are trying to get is going away...) We should try and handle it I think. Be it by just erroring out of here. > > return 0; > > @@ -256,8 +258,10 @@ static struct iio_channel *of_iio_channel_get_all(struct device *dev) > return chans; > > error_free_chans: > - for (i = 0; i < mapind; i++) > + for (i = 0; i < mapind; i++) { > + module_put(chans[i].indio_dev->driver_module); > iio_device_put(chans[i].indio_dev); > + } > kfree(chans); > return ERR_PTR(ret); > } > @@ -351,6 +355,7 @@ void iio_channel_release(struct iio_channel *channel) > { > if (!channel) > return; > + module_put(channel->indio_dev->driver_module); > iio_device_put(channel->indio_dev); > kfree(channel); > } > @@ -482,6 +487,7 @@ void iio_channel_release_all(struct iio_channel *channels) > struct iio_channel *chan = &channels[0]; > > while (chan->indio_dev) { > + module_put(chan->indio_dev->driver_module); > iio_device_put(chan->indio_dev); > chan++; > }