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

From: Greg Kroah-Hartman
Date: Thu Feb 15 2018 - 13:15:33 EST


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. */