From: Kent Gibson <warthog618@xxxxxxxxx> [ Upstream commit 2e202ad873365513c6ad72e29a531071dffa498a ] 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@xxxxxxxxx/ Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL") Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Kent Gibson <warthog618@xxxxxxxxx> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpio/gpiolib-cdev.c | 145 ++++++++++++++++++------------------ 1 file changed, 73 insertions(+), 72 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index e9faeaf65d14f..689c06cbbb457 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -1960,6 +1960,21 @@ 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 @@ -1974,6 +1989,41 @@ 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, @@ -2011,6 +2061,22 @@ 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 */ @@ -2018,80 +2084,24 @@ 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) { @@ -2100,16 +2110,7 @@ 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; } -- 2.27.0
