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

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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: aad955842d ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
This commit is contained in:
Kent Gibson 2020-12-28 00:10:40 +08:00 • committed by Bartosz Golaszewski
parent 5c8fe583cc
commit 2e202ad873
1 changed files with 73 additions and 72 deletions
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145
drivers/gpio/gpiolib-cdev.c
View file

@ -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;
}