linux-kernel - [PATCH] gpiolib: fix the size of the ngpios variable

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Date:   Sat,  5 Mar 2022 16:42:56 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <brgl@...ev.pl>
Subject: [PATCH] gpiolib: fix the size of the ngpios variable

The ngpio fields both in struct gpio_device as well as gpio_chip are
16 bit unsigned integers. Let's not risk an overflow and use the correct
size when reading the device property.

Fixes: 9dbd1ab20509 ("gpiolib: check the 'ngpios' property in core gpiolib code")
Signed-off-by: Bartosz Golaszewski <brgl@...ev.pl>
---
 drivers/gpio/gpiolib.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a3d14277f17c..147b86db16aa 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -607,7 +607,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	int base = gc->base;
 	unsigned int i;
 	int ret = 0;
-	u32 ngpios;
+	u16 ngpios;
 
 	if (gc->fwnode)
 		fwnode = gc->fwnode;
@@ -665,7 +665,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	 * of GPIO lines.
 	 */
 	if (gc->ngpio == 0) {
-		ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
+		ret = device_property_read_u16(&gdev->dev, "ngpios", &ngpios);
 		if (ret == -ENODATA)
 			/*
 			 * -ENODATA means that there is no property found and
-- 
2.30.1