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| author | William Breathitt Gray <william.gray@linaro.org> | 2023-04-06 17:40:10 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-11 17:03:01 +0300 |
| commit | 9fd4768b09379c5513c3be58d9f9ab57f05a4b0c (patch) | |
| tree | f8a5dc78ed8a7d8e02a3d1525a158d92ef9b9179 /drivers/iio | |
| parent | c38a4eb8aa47c80ea546e087b9f21c9d5757d9d7 (diff) | |
| download | linux-9fd4768b09379c5513c3be58d9f9ab57f05a4b0c.tar.xz | |
iio: addac: stx104: Fix race condition for stx104_write_raw()
commit 9740827468cea80c42db29e7171a50e99acf7328 upstream.
The priv->chan_out_states array and actual DAC value can become
mismatched if stx104_write_raw() is called concurrently. Prevent such a
race condition by utilizing a mutex.
Fixes: 97a445dad37a ("iio: Add IIO support for the DAC on the Apex Embedded Systems STX104")
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/c95c9a77fcef36b2a052282146950f23bbc1ebdc.1680790580.git.william.gray@linaro.org
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/iio')
| -rw-r--r-- | drivers/iio/addac/stx104.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/iio/addac/stx104.c b/drivers/iio/addac/stx104.c index 46b46b7a3c8d..b658a75d4e3a 100644 --- a/drivers/iio/addac/stx104.c +++ b/drivers/iio/addac/stx104.c @@ -15,6 +15,7 @@ #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> +#include <linux/mutex.h> #include <linux/spinlock.h> #include <linux/types.h> @@ -69,10 +70,12 @@ struct stx104_reg { /** * struct stx104_iio - IIO device private data structure + * @lock: synchronization lock to prevent I/O race conditions * @chan_out_states: channels' output states * @reg: I/O address offset for the device registers */ struct stx104_iio { + struct mutex lock; unsigned int chan_out_states[STX104_NUM_OUT_CHAN]; struct stx104_reg __iomem *reg; }; @@ -182,9 +185,12 @@ static int stx104_write_raw(struct iio_dev *indio_dev, if ((unsigned int)val > 65535) return -EINVAL; + mutex_lock(&priv->lock); + priv->chan_out_states[chan->channel] = val; iowrite16(val, &priv->reg->dac[chan->channel]); + mutex_unlock(&priv->lock); return 0; } return -EINVAL; @@ -355,6 +361,8 @@ static int stx104_probe(struct device *dev, unsigned int id) indio_dev->name = dev_name(dev); + mutex_init(&priv->lock); + /* configure device for software trigger operation */ iowrite8(0, &priv->reg->acr); |