gpiolib: Separate GPIO_GET_LINEINFO_WATCH_IOCTL conditional

We already have two conditionals inside the outer one to check
if the command is GPIO_GET_LINEINFO_WATCH_IOCTL. I think it's
time to actually do what I have proposed in the first place, i.e.
to separate GPIO_GET_LINEINFO_WATCH_IOCTL from GPIO_GET_LINEINFO_IOCTL.
It's +13 LOCs, and surprisingly only +13 bytes of binary on x86_32,
but for the price of much better readability.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20200525194028.74236-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 2e4aacb..34259c1 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1265,8 +1265,7 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
                        return -EFAULT;
                return 0;
-       } else if (cmd == GPIO_GET_LINEINFO_IOCTL ||
-                  cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
+       } else if (cmd == GPIO_GET_LINEINFO_IOCTL) {
                struct gpioline_info lineinfo;
 
                if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
@@ -1278,23 +1277,37 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
                hwgpio = gpio_chip_hwgpio(desc);
 
-               if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL &&
-                   test_bit(hwgpio, priv->watched_lines))
-                       return -EBUSY;
-
                gpio_desc_to_lineinfo(desc, &lineinfo);
 
                if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
                        return -EFAULT;
-
-               if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL)
-                       set_bit(hwgpio, priv->watched_lines);
-
                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 gpioline_info lineinfo;
+
+               if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+                       return -EFAULT;
+
+               desc = gpiochip_get_desc(gc, lineinfo.line_offset);
+               if (IS_ERR(desc))
+                       return PTR_ERR(desc);
+
+               hwgpio = gpio_chip_hwgpio(desc);
+
+               if (test_bit(hwgpio, priv->watched_lines))
+                       return -EBUSY;
+
+               gpio_desc_to_lineinfo(desc, &lineinfo);
+
+               if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
+                       return -EFAULT;
+
+               set_bit(hwgpio, priv->watched_lines);
+               return 0;
        } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
                if (copy_from_user(&offset, ip, sizeof(offset)))
                        return -EFAULT;