Re: [PATCH 11/12] v4l2-compat-ioctl32.c: don't copy back the result for certain errors

[Sakari Ailus <sakari.ailus@iki.fi>]

Hi Hans,

On Fri, Jan 26, 2018 at 01:43:26PM +0100, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
> 
> Some ioctls need to copy back the result even if the ioctl returned
> an error. However, don't do this for the error codes -ENOTTY, -EFAULT
> and -ENOIOCTLCMD. It makes no sense in those cases.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Shouldn't such a change be made to video_usercopy() as well? Doesn't need
to be in this set though.

> ---
>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> index 790473b45a21..2aa9b43daf60 100644
> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> @@ -966,6 +966,9 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
>  		set_fs(old_fs);
>  	}
>  
> +	if (err == -ENOTTY || err == -EFAULT || err == -ENOIOCTLCMD)
> +		return err;
> +
>  	/* Special case: even after an error we need to put the
>  	   results back for these ioctls since the error_idx will
>  	   contain information on which control failed. */

-- 
Sakari Ailus
e-mail: sakari.ailus@iki.fi