Re: [PATCH v6 6/6] iio: imu: st_lsm6dsx: prohibit the use of events and buffered reads simultaneously

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> When events and buffered reads is enabled simultaneously, and the first
> event accours the interrupt pin stays high.
> 
> This can be reverted when we find a solution to allow events and
> buffered reads simultaneously.
> 
> Signed-off-by: Sean Nyekjaer <sean@geanix.com>
> ---
> Changes since v4:
>  * Use fifo configuration mutex to prevent a race in hw->enable_event check.
> 
> Changes since v5:
>  * Updated do not return without unlocking mutexes
>  * Lock mutex before unlock
>  * Runtime tested ;-)
> 

[...]

> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> @@ -1340,8 +1340,12 @@ static int st_lsm6dsx_write_event_config(struct iio_dev *iio_dev,
>  	if (type != IIO_EV_TYPE_THRESH)
>  		return -EINVAL;
>  
> -	if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS)
> -		return -EBUSY;
> +	mutex_lock(&hw->conf_lock);
> +
> +	if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS) {
> +		err = -EBUSY;
> +		goto out;
> +	}

This patch is still broken!!! Returning in case of error you need to relase the
lock.

>  
>  	/* do not enable events if they are already enabled */
>  	if (state && hw->enable_event)
> @@ -1357,7 +1361,10 @@ static int st_lsm6dsx_write_event_config(struct iio_dev *iio_dev,
>  
>  	hw->enable_event = state;
>  
> -	return 0;
> +out:
> +	mutex_unlock(&hw->conf_lock);
> +
> +	return err;
>  }
>  
>  int st_lsm6dsx_set_watermark(struct iio_dev *iio_dev, unsigned int val)
> -- 
> 2.23.0
> 

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