[3.13.y.z extended stable] Patch "iio: querying buffer scan_mask should return 0/1" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    iio: querying buffer scan_mask should return 0/1

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.3.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 1d62d021f7be5507cd452ee46faeeb78fbc53a8b Mon Sep 17 00:00:00 2001
From: Alec Berg <alecaberg at chromium.org>
Date: Wed, 19 Mar 2014 18:50:00 +0000
Subject: iio: querying buffer scan_mask should return 0/1

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 at chromium.org>
Signed-off-by: Jonathan Cameron <jic23 at kernel.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 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 7f9152c..4bf831a 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -136,7 +136,8 @@ 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);
@@ -837,7 +838,8 @@ 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);

--
1.9.1