linux-kernel - [PATCH] regulator: core: Fix error return for /sys access

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Message-Id: <f37f2a1276efcb34cf3b7f1a25481175be048806.1568143348.git.hns@goldelico.com>
Date:   Tue, 10 Sep 2019 21:22:29 +0200
From:   "H. Nikolaus Schaller" <hns@...delico.com>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, Adam Ford <aford173@...il.com>
Cc:     linux-kernel@...r.kernel.org, letux-kernel@...nphoenux.org,
        kernel@...a-handheld.com,
        "H. Nikolaus Schaller" <hns@...delico.com>
Subject: [PATCH] regulator: core: Fix error return for /sys access

regulator_uV_show() is missing error handling if regulator_get_voltage_rdev()
returns negative values. Instead it prints the errno as a string, e.g. -EINVAL
as "-22" which could be interpreted as -22 µV.

We also do not need to hold the lock while converting the integer to a string.

Reported-by: Adam Ford <aford173@...il.com>
Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
---
 drivers/regulator/core.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index e0c0cf462004..ea48cb5a68b8 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -564,13 +564,15 @@ static ssize_t regulator_uV_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	struct regulator_dev *rdev = dev_get_drvdata(dev);
-	ssize_t ret;
+	int uV;
 
 	regulator_lock(rdev);
-	ret = sprintf(buf, "%d\n", regulator_get_voltage_rdev(rdev));
+	uV = regulator_get_voltage_rdev(rdev);
 	regulator_unlock(rdev);
 
-	return ret;
+	if (uV < 0)
+		return uV;
+	return sprintf(buf, "%d\n", uV);
 }
 static DEVICE_ATTR(microvolts, 0444, regulator_uV_show, NULL);
 
-- 
2.19.1