[PATCH 3.12 055/182] iio: querying buffer scan_mask should return 0/1

Jiri Slaby
2014-05-13T09:55:28Z

From: Alec Berg <alecaberg@chromium.org>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 2076a20fc1a06f7b0333c62a2bb4eeeac7ed1bcb upstream.

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>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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 2db7dcd826b9..376de1cc85db 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -119,7 +119,8 @@ 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);
@@ -789,7 +790,8 @@ 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);

--
1.9.3