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    SubjectRe: [PATCH] iio: gyro: ssp_gyro_sensor: Use devm_iio_device_register
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    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 <vthakkar1994@gmail.com>
    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);
    >



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