linux-kernel - [PATCH v1 2/3] gpiolib: sysfs: Move kstrtox() calls outside of the mutex lock

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Message-Id: <20220209113117.25760-2-andriy.shevchenko@linux.intel.com>
Date:   Wed,  9 Feb 2022 13:31:16 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>
Subject: [PATCH v1 2/3] gpiolib: sysfs: Move kstrtox() calls outside of the mutex lock

In a few places we perform kstrtox() operations under mutex that
do not require any locking. Move them outside of the mutex locks.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 drivers/gpio/gpiolib-sysfs.c | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 57d8ecab53b7..e7828d4dc7a8 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -121,24 +121,18 @@ static ssize_t value_store(struct device *dev,
 {
 	struct gpiod_data *data = dev_get_drvdata(dev);
 	struct gpio_desc *desc = data->desc;
-	ssize_t status = 0;
+	ssize_t status;
+	long value;
+
+	status = kstrtol(buf, 0, &value);
 
 	mutex_lock(&data->mutex);
 
 	if (!test_bit(FLAG_IS_OUT, &desc->flags)) {
 		status = -EPERM;
-	} else {
-		long		value;
-
-		if (size <= 2 && isdigit(buf[0]) &&
-		    (size == 1 || buf[1] == '\n'))
-			value = buf[0] - '0';
-		else
-			status = kstrtol(buf, 0, &value);
-		if (status == 0) {
-			gpiod_set_value_cansleep(desc, value);
-			status = size;
-		}
+	} else if (status == 0) {
+		gpiod_set_value_cansleep(desc, value);
+		status = size;
 	}
 
 	mutex_unlock(&data->mutex);
@@ -342,11 +336,13 @@ static ssize_t active_low_store(struct device *dev,
 	ssize_t			status;
 	long			value;
 
+	status = kstrtol(buf, 0, &value);
+	if (status)
+		return status;
+
 	mutex_lock(&data->mutex);
 
-	status = kstrtol(buf, 0, &value);
-	if (status == 0)
-		status = gpio_sysfs_set_active_low(dev, value);
+	status = gpio_sysfs_set_active_low(dev, value);
 
 	mutex_unlock(&data->mutex);
 
-- 
2.34.1