[V2,next] media: uvcvideo: Fix memory leak when gpiod_to_irq fails

From: Colin Ian King <colin.king@canonical.com>

Currently when the call to gpiod_to_irq fails the error return
path does not kfree the recently allocated object 'unit'. Fix this
swapping the order of the irq call and the allocation of unit.

Thanks to Ricardo Ribalda for suggesting this fix.

Addresses-Coverity: ("Resource leak")
Fixes: 2886477ff987 ("media: uvcvideo: Implement UVC_EXT_GPIO_UNIT")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---

V2: swap order of gpiod_to_irq call and allocation of unit to simplify
    error cleanup.

---
 drivers/media/usb/uvc/uvc_driver.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Thanks for the fix!

On Thu, Jan 28, 2021 at 2:59 PM Colin King <colin.king@canonical.com> wrote:
>
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently when the call to gpiod_to_irq fails the error return
> path does not kfree the recently allocated object 'unit'. Fix this
> swapping the order of the irq call and the allocation of unit.
>
> Thanks to Ricardo Ribalda for suggesting this fix.
>
> Addresses-Coverity: ("Resource leak")
> Fixes: 2886477ff987 ("media: uvcvideo: Implement UVC_EXT_GPIO_UNIT")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>

> ---
>
> V2: swap order of gpiod_to_irq call and allocation of unit to simplify
>     error cleanup.
>
> ---
>  drivers/media/usb/uvc/uvc_driver.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 1abc122a0977..f62e6cb66daf 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -1534,10 +1534,6 @@ static int uvc_gpio_parse(struct uvc_device *dev)
>         if (IS_ERR_OR_NULL(gpio_privacy))
>                 return PTR_ERR_OR_ZERO(gpio_privacy);
>
> -       unit = uvc_alloc_entity(UVC_EXT_GPIO_UNIT, UVC_EXT_GPIO_UNIT_ID, 0, 1);
> -       if (!unit)
> -               return -ENOMEM;
> -
>         irq = gpiod_to_irq(gpio_privacy);
>         if (irq < 0) {
>                 if (irq != EPROBE_DEFER)
> @@ -1546,6 +1542,10 @@ static int uvc_gpio_parse(struct uvc_device *dev)
>                 return irq;
>         }
>
> +       unit = uvc_alloc_entity(UVC_EXT_GPIO_UNIT, UVC_EXT_GPIO_UNIT_ID, 0, 1);
> +       if (!unit)
> +               return -ENOMEM;
> +
>         unit->gpio.gpio_privacy = gpio_privacy;
>         unit->gpio.irq = irq;
>         unit->gpio.bControlSize = 1;
> --
> 2.29.2
>