Re: [PATCH 6/8] iio: __iio_update_buffers: Split enable and disable path into helper functions

[Jonathan Cameron <jic23@kernel.org>]

On 13/05/15 15:04, Lars-Peter Clausen wrote:
> __iio_update_buffers is already a rather large function with many different
> error paths and it is going to get even larger. This patch factors out the
> device enable and device disable paths into separate helper functions.
> 
> The patch also re-implements iio_disable_all_buffers() using the new
> iio_disable_buffers() function removing a fair bit of redundant code.
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Also looks fine to me.
> ---
>  drivers/iio/industrialio-buffer.c | 174 +++++++++++++++++++++-----------------
>  1 file changed, 95 insertions(+), 79 deletions(-)
> 
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index 68e2669..dd04e35 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -539,29 +539,6 @@ static void iio_buffer_deactivate(struct iio_buffer *buffer)
>  	iio_buffer_put(buffer);
>  }
>  
> -void iio_disable_all_buffers(struct iio_dev *indio_dev)
> -{
> -	struct iio_buffer *buffer, *_buffer;
> -
> -	if (list_empty(&indio_dev->buffer_list))
> -		return;
> -
> -	if (indio_dev->setup_ops->predisable)
> -		indio_dev->setup_ops->predisable(indio_dev);
> -
> -	list_for_each_entry_safe(buffer, _buffer,
> -			&indio_dev->buffer_list, buffer_list)
> -		iio_buffer_deactivate(buffer);
> -
> -	if (indio_dev->setup_ops->postdisable)
> -		indio_dev->setup_ops->postdisable(indio_dev);
> -
> -	indio_dev->currentmode = INDIO_DIRECT_MODE;
> -
> -	if (indio_dev->available_scan_masks == NULL)
> -		kfree(indio_dev->active_scan_mask);
> -}
> -
>  static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
>  	struct iio_buffer *buffer)
>  {
> @@ -684,62 +661,40 @@ static int iio_verify_update(struct iio_dev *indio_dev,
>  	return 0;
>  }
>  
> -static int __iio_update_buffers(struct iio_dev *indio_dev,
> -		       struct iio_buffer *insert_buffer,
> -		       struct iio_buffer *remove_buffer)
> +static int iio_disable_buffers(struct iio_dev *indio_dev)
>  {
>  	int ret;
> -	const unsigned long *old_mask;
> -	struct iio_device_config new_config;
>  
> -	ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
> -		&new_config);
> -	if (ret)
> -		return ret;
> +	/* Wind down existing buffers - iff there are any */
> +	if (list_empty(&indio_dev->buffer_list))
> +		return 0;
>  
> -	if (insert_buffer) {
> -		ret = iio_buffer_request_update(indio_dev, insert_buffer);
> +	if (indio_dev->setup_ops->predisable) {
> +		ret = indio_dev->setup_ops->predisable(indio_dev);
>  		if (ret)
> -			goto err_free_config;
> +			return ret;
>  	}
>  
> -	/* Wind down existing buffers - iff there are any */
> -	if (!list_empty(&indio_dev->buffer_list)) {
> -		if (indio_dev->setup_ops->predisable) {
> -			ret = indio_dev->setup_ops->predisable(indio_dev);
> -			if (ret)
> -				goto err_free_config;
> -		}
> -
> -		if (indio_dev->setup_ops->postdisable) {
> -			ret = indio_dev->setup_ops->postdisable(indio_dev);
> -			if (ret)
> -				goto err_free_config;
> -		}
> -
> -		indio_dev->currentmode = INDIO_DIRECT_MODE;
> +	if (indio_dev->setup_ops->postdisable) {
> +		ret = indio_dev->setup_ops->postdisable(indio_dev);
> +		if (ret)
> +			return ret;
>  	}
> -	/* Keep a copy of current setup to allow roll back */
> -	old_mask = indio_dev->active_scan_mask;
> -	if (!indio_dev->available_scan_masks)
> -		indio_dev->active_scan_mask = NULL;
>  
> -	if (remove_buffer)
> -		iio_buffer_deactivate(remove_buffer);
> -	if (insert_buffer)
> -		iio_buffer_activate(indio_dev, insert_buffer);
> +	indio_dev->currentmode = INDIO_DIRECT_MODE;
>  
> -	/* If no buffers in list, we are done */
> -	if (list_empty(&indio_dev->buffer_list)) {
> -		indio_dev->currentmode = INDIO_DIRECT_MODE;
> -		iio_free_scan_mask(indio_dev, old_mask);
> -		return 0;
> -	}
> +	return 0;
> +}
>  
> -	indio_dev->currentmode = new_config.mode;
> -	indio_dev->active_scan_mask = new_config.scan_mask;
> -	indio_dev->scan_timestamp = new_config.scan_timestamp;
> -	indio_dev->scan_bytes = new_config.scan_bytes;
> +static int iio_enable_buffers(struct iio_dev *indio_dev,
> +	struct iio_device_config *config)
> +{
> +	int ret;
> +
> +	indio_dev->currentmode = config->mode;
> +	indio_dev->active_scan_mask = config->scan_mask;
> +	indio_dev->scan_timestamp = config->scan_timestamp;
> +	indio_dev->scan_bytes = config->scan_bytes;
>  
>  	iio_update_demux(indio_dev);
>  
> @@ -749,7 +704,7 @@ static int __iio_update_buffers(struct iio_dev *indio_dev,
>  		if (ret) {
>  			dev_dbg(&indio_dev->dev,
>  			       "Buffer not started: buffer preenable failed (%d)\n", ret);
> -			goto error_remove_inserted;
> +			goto err_undo_config;
>  		}
>  	}
>  
> @@ -761,7 +716,7 @@ static int __iio_update_buffers(struct iio_dev *indio_dev,
>  			dev_dbg(&indio_dev->dev,
>  				"Buffer not started: update scan mode failed (%d)\n",
>  				ret);
> -			goto error_run_postdisable;
> +			goto err_run_postdisable;
>  		}
>  	}
>  
> @@ -770,24 +725,72 @@ static int __iio_update_buffers(struct iio_dev *indio_dev,
>  		if (ret) {
>  			dev_dbg(&indio_dev->dev,
>  			       "Buffer not started: postenable failed (%d)\n", ret);
> -			goto error_run_postdisable;
> +			goto err_run_postdisable;
>  		}
>  	}
>  
> -	iio_free_scan_mask(indio_dev, old_mask);
> -
>  	return 0;
>  
> -error_run_postdisable:
> +err_run_postdisable:
>  	if (indio_dev->setup_ops->postdisable)
>  		indio_dev->setup_ops->postdisable(indio_dev);
> -error_remove_inserted:
> +err_undo_config:
>  	indio_dev->currentmode = INDIO_DIRECT_MODE;
> -	if (insert_buffer)
> -		iio_buffer_deactivate(insert_buffer);
> -	iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
> -	indio_dev->active_scan_mask = old_mask;
> +	indio_dev->active_scan_mask = NULL;
> +
>  	return ret;
> +}
> +
> +static int __iio_update_buffers(struct iio_dev *indio_dev,
> +		       struct iio_buffer *insert_buffer,
> +		       struct iio_buffer *remove_buffer)
> +{
> +	int ret;
> +	const unsigned long *old_mask;
> +	struct iio_device_config new_config;
> +
> +	ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
> +		&new_config);
> +	if (ret)
> +		return ret;
> +
> +	if (insert_buffer) {
> +		ret = iio_buffer_request_update(indio_dev, insert_buffer);
> +		if (ret)
> +			goto err_free_config;
> +	}
> +
> +	/* Keep a copy of current setup to allow roll back */
> +	old_mask = indio_dev->active_scan_mask;
> +	indio_dev->active_scan_mask = NULL;
> +
> +	ret = iio_disable_buffers(indio_dev);
> +	if (ret) {
> +		iio_free_scan_mask(indio_dev, old_mask);
> +		goto err_free_config;
> +	}
> +
> +	if (remove_buffer)
> +		iio_buffer_deactivate(remove_buffer);
> +	if (insert_buffer)
> +		iio_buffer_activate(indio_dev, insert_buffer);
> +
> +	/* If no buffers in list, we are done */
> +	if (list_empty(&indio_dev->buffer_list)) {
> +		iio_free_scan_mask(indio_dev, old_mask);
> +		return 0;
> +	}
> +
> +	ret = iio_enable_buffers(indio_dev, &new_config);
> +	if (ret) {
> +		if (insert_buffer)
> +			iio_buffer_deactivate(insert_buffer);
> +		indio_dev->active_scan_mask = old_mask;
> +		goto err_free_config;
> +	}
> +
> +	iio_free_scan_mask(indio_dev, old_mask);
> +	return 0;
>  
>  err_free_config:
>  	iio_free_scan_mask(indio_dev, new_config.scan_mask);
> @@ -832,6 +835,19 @@ out_unlock:
>  }
>  EXPORT_SYMBOL_GPL(iio_update_buffers);
>  
> +void iio_disable_all_buffers(struct iio_dev *indio_dev)
> +{
> +	struct iio_buffer *buffer, *_buffer;
> +
> +	iio_disable_buffers(indio_dev);
> +	iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
> +	indio_dev->active_scan_mask = NULL;
> +
> +	list_for_each_entry_safe(buffer, _buffer,
> +			&indio_dev->buffer_list, buffer_list)
> +		iio_buffer_deactivate(buffer);
> +}
> +
>  static ssize_t iio_buffer_store_enable(struct device *dev,
>  				       struct device_attribute *attr,
>  				       const char *buf,
>