Re: [PATCH 12/15] iio: fyro: itg3200_core: do not use internal iio_dev lock

Jonathan Cameron
2022-10-23T10:57:15Z

On Tue, 20 Sep 2022 13:28:18 +0200
Nuno Sá <nuno.sa@analog.com> wrote:

> The iio_device lock is only meant for internal use. Hence define a
> device local lock to protect against concurrent accesses.
>
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> ---
> drivers/iio/gyro/itg3200_core.c | 9 ++++++---
> include/linux/iio/gyro/itg3200.h | 2 ++
> 2 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/gyro/itg3200_core.c b/drivers/iio/gyro/itg3200_core.c
> index 0491c64e1b32..358aa8ac0c6b 100644
> --- a/drivers/iio/gyro/itg3200_core.c
> +++ b/drivers/iio/gyro/itg3200_core.c
> @@ -18,6 +18,7 @@
> #include <linux/slab.h>
> #include <linux/stat.h>
> #include <linux/module.h>
> +#include <linux/mutex.h>
> #include <linux/delay.h>
>
> #include <linux/iio/iio.h>
> @@ -131,6 +132,7 @@ static int itg3200_write_raw(struct iio_dev *indio_dev,
> int val2,
> long mask)
> {
> + struct itg3200 *st = iio_priv(indio_dev);
> int ret;
> u8 t;
>
> @@ -139,11 +141,11 @@ static int itg3200_write_raw(struct iio_dev *indio_dev,
> if (val == 0 || val2 != 0)
> return -EINVAL;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
>
> ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &t);
> if (ret) {
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
> return ret;
> }
> t = ((t & ITG3200_DLPF_CFG_MASK) ? 1000u : 8000u) / val - 1;
> @@ -152,7 +154,7 @@ static int itg3200_write_raw(struct iio_dev *indio_dev,
> ITG3200_REG_SAMPLE_RATE_DIV,
> t);
>
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
> return ret;
>
> default:
> @@ -307,6 +309,7 @@ static int itg3200_probe(struct i2c_client *client,
> return -ENOMEM;
>
> st = iio_priv(indio_dev);
> + mutex_init(&st->lock);
>
> ret = iio_read_mount_matrix(&client->dev, &st->orientation);
> if (ret)
> diff --git a/include/linux/iio/gyro/itg3200.h b/include/linux/iio/gyro/itg3200.h
> index a602fe7b84fa..74b6d1cadc86 100644
> --- a/include/linux/iio/gyro/itg3200.h
> +++ b/include/linux/iio/gyro/itg3200.h
> @@ -102,6 +102,8 @@ struct itg3200 {
> struct i2c_client *i2c;
> struct iio_trigger *trig;
> struct iio_mount_matrix orientation;
> + /* lock to protect against multiple access to the device */
> + struct mutex lock;
> };
>
> enum ITG3200_SCAN_INDEX {