From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from saturn.retrosnub.co.uk ([178.18.118.26]:52118 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755343AbbITTSg (ORCPT ); Sun, 20 Sep 2015 15:18:36 -0400 Subject: Re: [PATCH] iio: gyro: ssp_gyro_sensor: Use devm_iio_device_register To: Vaishali Thakkar References: <20150914160849.GA21748@localhost> Cc: Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Karol Wrona From: Jonathan Cameron Message-ID: <55FF068A.30302@kernel.org> Date: Sun, 20 Sep 2015 20:18:34 +0100 MIME-Version: 1.0 In-Reply-To: <20150914160849.GA21748@localhost> Content-Type: text/plain; charset=windows-1252 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 14/09/15 17:08, Vaishali Thakkar wrote: > Use resourced managed function devm_iio_device_register to > make error path simpler. To be compatible with the change, > the remove function is removed as it is now redundant. > > Signed-off-by: Vaishali Thakkar This patch is reasonable, but makes me wonder if there is an issue in the remove path for this driver. It relies on the ssp_sensors common module. That in ssp_spi.c uses the fact ssp_register_consumer has saved the struct iio_dev into a local array in the core driver. I think this means that a remove of this function will leave a possible null pointer de reference. Now I suspect that case doesn't actually occur because the relevant device elements are disabled whenever this module is removed. Having said that we might expect an ssp_unregister_consumer function that sets the relevant pointer back to null on removal so as to avoid any possible race conditions around driver removal / reprobing. A spot of defensive programming rather than necessarily a bug to be fixed! One little process thing. This driver was written by Karol so patches should probably always cc Karol as well as the more general maintainer / reviewers for IIO. Added cc. Jonathan > --- > drivers/iio/gyro/ssp_gyro_sensor.c | 12 +----------- > 1 file changed, 1 insertion(+), 11 deletions(-) > > diff --git a/drivers/iio/gyro/ssp_gyro_sensor.c b/drivers/iio/gyro/ssp_gyro_sensor.c > index 0a8afdd..ac88de7 100644 > --- a/drivers/iio/gyro/ssp_gyro_sensor.c > +++ b/drivers/iio/gyro/ssp_gyro_sensor.c > @@ -134,7 +134,7 @@ static int ssp_gyro_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, indio_dev); > > - ret = iio_device_register(indio_dev); > + ret = devm_iio_device_register(&pdev->dev, indio_dev); > if (ret < 0) > return ret; > > @@ -144,21 +144,11 @@ static int ssp_gyro_probe(struct platform_device *pdev) > return 0; > } > > -static int ssp_gyro_remove(struct platform_device *pdev) > -{ > - struct iio_dev *indio_dev = platform_get_drvdata(pdev); > - > - iio_device_unregister(indio_dev); > - > - return 0; > -} > - > static struct platform_driver ssp_gyro_driver = { > .driver = { > .name = SSP_GYROSCOPE_NAME, > }, > .probe = ssp_gyro_probe, > - .remove = ssp_gyro_remove, > }; > > module_platform_driver(ssp_gyro_driver); >