This is a note to let you know that I've just added the patch titled iio: adc: ad_sigma_delta: do not use internal iio_dev lock to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: iio-adc-ad_sigma_delta-do-not-use-internal-iio_dev-lock.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 20228a1d5a55e7db0c6720840f2c7d2b48c55f69 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Nuno=20S=C3=A1?= <nuno.sa@xxxxxxxxxx> Date: Tue, 20 Sep 2022 13:28:07 +0200 Subject: iio: adc: ad_sigma_delta: do not use internal iio_dev lock MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Nuno Sá <nuno.sa@xxxxxxxxxx> 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: af3008485ea0 ("iio:adc: Add common code for ADI Sigma Delta devices") Signed-off-by: Nuno Sá <nuno.sa@xxxxxxxxxx> Reviewed-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx> Cc: <Stable@xxxxxxxxxxxxxxx> #No rush as race is very old. Link: https://lore.kernel.org/r/20220920112821.975359-2-nuno.sa@xxxxxxxxxx Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/iio/adc/ad_sigma_delta.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/drivers/iio/adc/ad_sigma_delta.c +++ b/drivers/iio/adc/ad_sigma_delta.c @@ -283,10 +283,10 @@ int ad_sigma_delta_single_conversion(str 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 @@ out: 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; Patches currently in stable-queue which might be from nuno.sa@xxxxxxxxxx are queue-5.4/iio-adc-ad_sigma_delta-do-not-use-internal-iio_dev-lock.patch