diff options
| author | William Breathitt Gray <william.gray@linaro.org> | 2023-04-06 10:40:10 -0400 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2023-04-10 12:26:33 +0100 |
| commit | 9740827468cea80c42db29e7171a50e99acf7328 (patch) | |
| tree | b1b79488918389314a5e1859735079da803c0ae8 | |
| parent | 86fb8b3aebd7f2236c11521ee0c460cceb0e4d6f (diff) | |
| download | iio-9740827468cea80c42db29e7171a50e99acf7328.tar.gz | |
iio: addac: stx104: Fix race condition for stx104_write_raw()
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>
| -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 e45b70aa5bb7a2..4239aafe42fc8c 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; }; @@ -178,9 +181,12 @@ 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; @@ -351,6 +357,8 @@ 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); |