patch "iio: scd4x: check return of scd4x_write_and_fetch" added to char-misc-linus

patch "iio: scd4x: check return of scd4x_write_and_fetch" added to char-misc-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    iio: scd4x: check return of scd4x_write_and_fetch

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From f50232193e61cf89a73130b5e843fef30763c428 Mon Sep 17 00:00:00 2001
From: Tom Rix <trix@redhat.com>
Date: Mon, 28 Feb 2022 18:52:23 -0800
Subject: iio: scd4x: check return of scd4x_write_and_fetch

Clang static analysis reports this problem
scd4x.c:474:10: warning: The left operand of '==' is a
  garbage value
  if (val == 0xff) {
      ~~~ ^
val is only set from a successful call to scd4x_write_and_fetch()
So check it's return.

Fixes: 49d22b695cbb ("drivers: iio: chemical: Add support for Sensirion SCD4x CO2 sensor")
Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20220301025223.223223-1-trix@redhat.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/chemical/scd4x.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/chemical/scd4x.c b/drivers/iio/chemical/scd4x.c
index 20d4e7584e92..37143b5526ee 100644
--- a/drivers/iio/chemical/scd4x.c
+++ b/drivers/iio/chemical/scd4x.c
@@ -471,12 +471,15 @@ static ssize_t calibration_forced_value_store(struct device *dev,
 	ret = scd4x_write_and_fetch(state, CMD_FRC, arg, &val, sizeof(val));
 	mutex_unlock(&state->lock);
 
+	if (ret)
+		return ret;
+
 	if (val == 0xff) {
 		dev_err(dev, "forced calibration has failed");
 		return -EINVAL;
 	}
 
-	return ret ?: len;
+	return len;
 }
 
 static IIO_DEVICE_ATTR_RW(calibration_auto_enable, 0);
-- 
2.36.0