Re: [PATCH] iio: querying buffer scan_mask should return 0/1

[Jonathan Cameron <jic23@kernel.org>]

On 19/03/14 18:50, Alec Berg wrote:
> Ensure that querying the IIO buffer scan_mask returns a value of
> 0 or 1. Currently querying the scan mask has the value returned
> by test_bit(), which returns either true or false. For some
> architectures test_bit() may return -1 for true, which will appear
> to return an error when returning from iio_scan_mask_query().
>
> Additionally, it's important for the sysfs interface to consistently
> return the same thing when querying the scan_mask.
>
> Signed-off-by: Alec Berg <alecaberg@chromium.org>
Applied to the fixes-togreg branch of iio.git and
marked for stable.

This will probably now go in shortly after rc1.

Thanks,

Jonathan
> ---
>   drivers/iio/industrialio-buffer.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index c67d83b..fe25042 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -165,7 +165,8 @@ static ssize_t iio_scan_el_show(struct device *dev,
>   	int ret;
>   	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>
> -	ret = test_bit(to_iio_dev_attr(attr)->address,
> +	/* Ensure ret is 0 or 1. */
> +	ret = !!test_bit(to_iio_dev_attr(attr)->address,
>   		       indio_dev->buffer->scan_mask);
>
>   	return sprintf(buf, "%d\n", ret);
> @@ -866,7 +867,8 @@ int iio_scan_mask_query(struct iio_dev *indio_dev,
>   	if (!buffer->scan_mask)
>   		return 0;
>
> -	return test_bit(bit, buffer->scan_mask);
> +	/* Ensure return value is 0 or 1. */
> +	return !!test_bit(bit, buffer->scan_mask);
>   };
>   EXPORT_SYMBOL_GPL(iio_scan_mask_query);
>
>