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

Jonathan Cameron
2014-03-19T20:31:47Z

On March 19, 2014 6:50:44 PM GMT+00:00, Alec Berg <alecaberg@chromium.org> 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().
I'm curious now. Which architectures? Change is fine BTW. Will pick when I get a few mins...
>
>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>
>---
> 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);
>

--
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