From 1bf7ba400173c3a134aae3187b550d79c2a5f585 Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Wed, 8 Jul 2020 12:15:54 +0800 Subject: [PATCH] gpiolib: cdev: remove recalculation of offset Remove recalculation of offset from desc, where desc itself was calculated from offset. There is no benefit from the desc -> hwgpio conversion in this context. The only implicit benefit of the offset -> desc -> hwgpio is the range check in the offset -> desc, but where desc is required you still get that, and where desc isn't required it is simpler to perform the range check directly. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index b2b26dc25051..c86fb9305681 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -832,7 +832,6 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) void __user *ip = (void __user *)arg; struct gpio_desc *desc; __u32 offset; - int hwgpio; /* We fail any subsequent ioctl():s when the chip is gone */ if (!gc) @@ -860,12 +859,11 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 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); - hwgpio = gpio_chip_hwgpio(desc); - gpio_desc_to_lineinfo(desc, &lineinfo); if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) @@ -881,19 +879,18 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 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); - hwgpio = gpio_chip_hwgpio(desc); - - if (test_and_set_bit(hwgpio, cdev->watched_lines)) + if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines)) return -EBUSY; gpio_desc_to_lineinfo(desc, &lineinfo); if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { - clear_bit(hwgpio, cdev->watched_lines); + clear_bit(lineinfo.line_offset, cdev->watched_lines); return -EFAULT; } @@ -902,13 +899,10 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if (copy_from_user(&offset, ip, sizeof(offset))) return -EFAULT; - desc = gpiochip_get_desc(gc, offset); - if (IS_ERR(desc)) - return PTR_ERR(desc); + if (offset >= cdev->gdev->ngpio) + return -EINVAL; - hwgpio = gpio_chip_hwgpio(desc); - - if (!test_and_clear_bit(hwgpio, cdev->watched_lines)) + if (!test_and_clear_bit(offset, cdev->watched_lines)) return -EBUSY; return 0;