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

[Luis Henriques]

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-3.11.y-queue branch of the 3.11.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-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From b82e01dcf1fbf56ce57a9724cd0dab7cf12a716b 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: Luis Henriques <luis.henriques 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 e73033f..54adea8 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);
@@ -760,7 +761,8 @@ 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