Commit 2e202ad8 authored by Kent Gibson's avatar Kent Gibson Committed by Bartosz Golaszewski
Browse files

gpiolib: cdev: fix frame size warning in gpio_ioctl() 

The kernel test robot reports the following warning in [1]:

 drivers/gpio/gpiolib-cdev.c: In function 'gpio_ioctl':
 >>drivers/gpio/gpiolib-cdev.c:1437:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]

Refactor gpio_ioctl() to handle each ioctl in its own helper function
and so reduce the variables stored on the stack to those explicitly
required to service the ioctl at hand.

The lineinfo_get_v1() helper handles both the GPIO_GET_LINEINFO_IOCTL
and GPIO_GET_LINEINFO_WATCH_IOCTL, as per the corresponding v2
implementation - lineinfo_get().

[1] https://lore.kernel.org/lkml/202012270910.VW3qc1ER-lkp@intel.com/



Fixes: aad95584 ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Reported-by: default avatarkernel test robot <lkp@intel.com>
Signed-off-by: default avatarKent Gibson <warthog618@gmail.com>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
parent 5c8fe583

drivers/gpio/gpiolib-cdev.c

+73 −72
Original line number Diff line number Diff line
@@ -1979,6 +1979,21 @@ struct gpio_chardev_data { 
#endif

};



static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)

{

	struct gpio_device *gdev = cdev->gdev;

	struct gpiochip_info chipinfo;



	memset(&chipinfo, 0, sizeof(chipinfo));



	strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));

	strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));

	chipinfo.lines = gdev->ngpio;

	if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))

		return -EFAULT;

	return 0;

}



#ifdef CONFIG_GPIO_CDEV_V1

/*

 * returns 0 if the versions match, else the previously selected ABI version
@@ -1993,6 +2008,41 @@ static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata, 


	return abiv;

}



static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,

			   bool watch)

{

	struct gpio_desc *desc;

	struct gpioline_info lineinfo;

	struct gpio_v2_line_info lineinfo_v2;



	if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))

		return -EFAULT;



	/* this doubles as a range check on line_offset */

	desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);

	if (IS_ERR(desc))

		return PTR_ERR(desc);



	if (watch) {

		if (lineinfo_ensure_abi_version(cdev, 1))

			return -EPERM;



		if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))

			return -EBUSY;

	}



	gpio_desc_to_lineinfo(desc, &lineinfo_v2);

	gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);



	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {

		if (watch)

			clear_bit(lineinfo.line_offset, cdev->watched_lines);

		return -EFAULT;

	}



	return 0;

}

#endif



static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
@@ -2030,6 +2080,22 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, 
	return 0;

}



static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)

{

	__u32 offset;



	if (copy_from_user(&offset, ip, sizeof(offset)))

		return -EFAULT;



	if (offset >= cdev->gdev->ngpio)

		return -EINVAL;



	if (!test_and_clear_bit(offset, cdev->watched_lines))

		return -EBUSY;



	return 0;

}



/*

 * gpio_ioctl() - ioctl handler for the GPIO chardev

 */
@@ -2037,80 +2103,24 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
{

	struct gpio_chardev_data *cdev = file->private_data;

	struct gpio_device *gdev = cdev->gdev;

	struct gpio_chip *gc = gdev->chip;

	void __user *ip = (void __user *)arg;

	__u32 offset;



	/* We fail any subsequent ioctl():s when the chip is gone */

	if (!gc)

	if (!gdev->chip)

		return -ENODEV;



	/* Fill in the struct and pass to userspace */

	if (cmd == GPIO_GET_CHIPINFO_IOCTL) {

		struct gpiochip_info chipinfo;



		memset(&chipinfo, 0, sizeof(chipinfo));



		strscpy(chipinfo.name, dev_name(&gdev->dev),

			sizeof(chipinfo.name));

		strscpy(chipinfo.label, gdev->label,

			sizeof(chipinfo.label));

		chipinfo.lines = gdev->ngpio;

		if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))

			return -EFAULT;

		return 0;

		return chipinfo_get(cdev, ip);

#ifdef CONFIG_GPIO_CDEV_V1

	} else if (cmd == GPIO_GET_LINEINFO_IOCTL) {

		struct gpio_desc *desc;

		struct gpioline_info lineinfo;

		struct gpio_v2_line_info lineinfo_v2;



		if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))

			return -EFAULT;



		/* this doubles as a range check on line_offset */

		desc = gpiochip_get_desc(gc, lineinfo.line_offset);

		if (IS_ERR(desc))

			return PTR_ERR(desc);



		gpio_desc_to_lineinfo(desc, &lineinfo_v2);

		gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);



		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))

			return -EFAULT;

		return 0;

	} else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {

		return linehandle_create(gdev, ip);

	} else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {

		return lineevent_create(gdev, ip);

	} else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {

		struct gpio_desc *desc;

		struct gpioline_info lineinfo;

		struct gpio_v2_line_info lineinfo_v2;



		if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))

			return -EFAULT;



		/* this doubles as a range check on line_offset */

		desc = gpiochip_get_desc(gc, lineinfo.line_offset);

		if (IS_ERR(desc))

			return PTR_ERR(desc);



		if (lineinfo_ensure_abi_version(cdev, 1))

			return -EPERM;



		if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))

			return -EBUSY;



		gpio_desc_to_lineinfo(desc, &lineinfo_v2);

		gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);



		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {

			clear_bit(lineinfo.line_offset, cdev->watched_lines);

			return -EFAULT;

		}



		return 0;

	} else if (cmd == GPIO_GET_LINEINFO_IOCTL ||

		   cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {

		return lineinfo_get_v1(cdev, ip,

				       cmd == GPIO_GET_LINEINFO_WATCH_IOCTL);

#endif /* CONFIG_GPIO_CDEV_V1 */

	} else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL ||

		   cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) {
@@ -2119,16 +2129,7 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	} else if (cmd == GPIO_V2_GET_LINE_IOCTL) {

		return linereq_create(gdev, ip);

	} else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {

		if (copy_from_user(&offset, ip, sizeof(offset)))

			return -EFAULT;



		if (offset >= cdev->gdev->ngpio)

			return -EINVAL;



		if (!test_and_clear_bit(offset, cdev->watched_lines))

			return -EBUSY;



		return 0;

		return lineinfo_unwatch(cdev, ip);

	}

	return -EINVAL;

}