[PATCH 4.9 47/88] media: v4l2-compat-ioctl32.c: dont copy back the result for certain errors

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hans Verkuil <hans.verkuil@xxxxxxxxx>

commit d83a8243aaefe62ace433e4384a4f077bed86acb upstream.

Some ioctls need to copy back the result even if the ioctl returned
an error. However, don't do this for the error code -ENOTTY.
It makes no sense in that cases.

Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -956,6 +956,9 @@ static long do_video_ioctl(struct file *
 		set_fs(old_fs);
 	}
 
+	if (err == -ENOTTY)
+		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. */