linux-kernel - [PATCH 3.2 127/140] media: v4l2-ioctl.c: don't copy back the result for -ENOTTY

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Message-ID: <lsq.1519831222.825418476@decadent.org.uk>
Date:   Wed, 28 Feb 2018 15:20:22 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Sakari Ailus" <sakari.ailus@...ux.intel.com>,
        "Mauro Carvalho Chehab" <mchehab@...pensource.com>,
        "Hans Verkuil" <hans.verkuil@...co.com>,
        "Hans Verkuil" <hverkuil@...all.nl>
Subject: [PATCH 3.2 127/140] media: v4l2-ioctl.c: don't copy back the 
 result for -ENOTTY

3.2.100-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Hans Verkuil <hverkuil@...all.nl>

From: Hans Verkuil <hans.verkuil@...co.com>

commit 181a4a2d5a0a7b43cab08a70710d727e7764ccdd 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@...co.com>
Acked-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...pensource.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/media/video/v4l2-ioctl.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index 639abeee3392..bae5dd776d82 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -2308,8 +2308,10 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
 
 	/* Handles IOCTL */
 	err = func(file, cmd, parg);
-	if (err == -ENOIOCTLCMD)
-		err = -EINVAL;
+	if (err == -ENOTTY || err == -ENOIOCTLCMD) {
+		err = -ENOTTY;
+		goto out;
+	}
 
 	if (has_array_args) {
 		*kernel_ptr = user_ptr;