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Commit bcb052a8 authored by Nuno Sá's avatar Nuno Sá Committed by Greg Kroah-Hartman
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iio: adc: ad_sigma_delta: do not use internal iio_dev lock 



commit 20228a1d5a55e7db0c6720840f2c7d2b48c55f69 upstream.

Drop 'mlock' usage by making use of iio_device_claim_direct_mode().
This change actually makes sure we cannot do a single conversion while
buffering is enable. Note there was a potential race in the previous
code since we were only acquiring the lock after checking if the bus is
enabled.

Fixes: af300848 ("iio:adc: Add common code for ADI Sigma Delta devices")
Signed-off-by: default avatarNuno Sá <nuno.sa@analog.com>
Reviewed-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Cc: <Stable@vger.kernel.org> #No rush as race is very old.
Link: https://lore.kernel.org/r/20220920112821.975359-2-nuno.sa@analog.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ad4eb32c

drivers/iio/adc/ad_sigma_delta.c

+4 −4
Original line number Diff line number Diff line
@@ -283,10 +283,10 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, 
	unsigned int data_reg;

	int ret = 0;



	if (iio_buffer_enabled(indio_dev))

		return -EBUSY;

	ret = iio_device_claim_direct_mode(indio_dev);

	if (ret)

		return ret;



	mutex_lock(&indio_dev->mlock);

	ad_sigma_delta_set_channel(sigma_delta, chan->address);



	spi_bus_lock(sigma_delta->spi->master);
@@ -325,7 +325,7 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, 
	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);

	sigma_delta->bus_locked = false;

	spi_bus_unlock(sigma_delta->spi->master);

	mutex_unlock(&indio_dev->mlock);

	iio_device_release_direct_mode(indio_dev);



	if (ret)

		return ret;