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 my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>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
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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>
---
drivers/iio/adc/ad_sigma_delta.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index 261a9a6b45e1..d8570f620785 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -281,10 +281,10 @@ 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);
@@ -323,7 +323,7 @@ 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;
--
2.38.1
