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 <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index b2b26dc..c86fb93 100644 (file)
--- 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);
-
-               hwgpio = gpio_chip_hwgpio(desc);
+               if (offset >= cdev->gdev->ngpio)
+                       return -EINVAL;
 
-               if (!test_and_clear_bit(hwgpio, cdev->watched_lines))
+               if (!test_and_clear_bit(offset, cdev->watched_lines))
                        return -EBUSY;
 
                return 0;