Re: [PATCH][V2] iio: st_accel: fix iio_triggered_buffer_{pre,post}enable positions

[Jonathan Cameron <jic23@jic23.retrosnub.co.uk>]

On Wed, 29 May 2019 16:58:48 +0300
Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:

> The iio_triggered_buffer_{predisable,postenable} functions attach/detach
> the poll functions.
> 
> For the predisable hook, the disable code should occur before detaching
> the poll func, and for the postenable hook, the poll func should be
> attached before the enable code.
> 
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
I think this is fine, but I'd like an ack from Lorenzo / Denis.

Note to those who have missed the background on this, the aim is
to both tidy up drivers, but long term to allow for simpler reworking
of the core by ensuring consistency of ordering and what is done
in each of these hooks.

Thanks,

Jonathan

> ---
> Changelog v1 -> v2:
> * record the first error in st_accel_buffer_predisable() and return that 
> 
>  drivers/iio/accel/st_accel_buffer.c | 21 ++++++++++++---------
>  1 file changed, 12 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/iio/accel/st_accel_buffer.c b/drivers/iio/accel/st_accel_buffer.c
> index 7fddc137e91e..711ecd9bc898 100644
> --- a/drivers/iio/accel/st_accel_buffer.c
> +++ b/drivers/iio/accel/st_accel_buffer.c
> @@ -40,6 +40,10 @@ static int st_accel_buffer_postenable(struct iio_dev *indio_dev)
>  	int err;
>  	struct st_sensor_data *adata = iio_priv(indio_dev);
>  
> +	err = iio_triggered_buffer_postenable(indio_dev);
> +	if (err < 0)
> +		return err;
> +
>  	adata->buffer_data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
>  	if (adata->buffer_data == NULL) {
>  		err = -ENOMEM;
> @@ -51,34 +55,33 @@ static int st_accel_buffer_postenable(struct iio_dev *indio_dev)
>  	if (err < 0)
>  		goto st_accel_buffer_postenable_error;
>  
> -	err = iio_triggered_buffer_postenable(indio_dev);
> -	if (err < 0)
> -		goto st_accel_buffer_postenable_error;
> -
>  	return err;
>  
>  st_accel_buffer_postenable_error:
>  	kfree(adata->buffer_data);
>  allocate_memory_error:
> +	iio_triggered_buffer_predisable(indio_dev);
>  	return err;
>  }
>  
>  static int st_accel_buffer_predisable(struct iio_dev *indio_dev)
>  {
> -	int err;
> +	int err, err2;
>  	struct st_sensor_data *adata = iio_priv(indio_dev);
>  
> -	err = iio_triggered_buffer_predisable(indio_dev);
> -	if (err < 0)
> -		goto st_accel_buffer_predisable_error;
> -
>  	err = st_sensors_set_axis_enable(indio_dev, ST_SENSORS_ENABLE_ALL_AXIS);
>  	if (err < 0)
>  		goto st_accel_buffer_predisable_error;
>  
>  	err = st_sensors_set_enable(indio_dev, false);
> +	if (err < 0)
> +		goto st_accel_buffer_predisable_error;
>  
>  st_accel_buffer_predisable_error:
> +	err2 = iio_triggered_buffer_predisable(indio_dev);
> +	if (!err)
> +		err = err2;
> +
>  	kfree(adata->buffer_data);
>  	return err;
>  }