media: v4l2-ioctl.c: don't copy back the result for -ENOTTY

BugLink: http://bugs.launchpad.net/bugs/1756121

commit 181a4a2d upstream.

If the ioctl returned -ENOTTY, then don't bother copying
back the result as there is no point.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -2783,8 +2783,11 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
 
 	/* Handles IOCTL */
 	err = func(file, cmd, parg);
-	if (err == -ENOIOCTLCMD)
+	if (err == -ENOTTY || err == -ENOIOCTLCMD) {
 		err = -ENOTTY;
+		goto out;
+	}
+
 	if (err == 0) {
 		if (cmd == VIDIOC_DQBUF)
 			trace_v4l2_dqbuf(video_devdata(file)->minor, parg);