linux-kernel - [PATCH 3.16 240/254] media: v4l2-ioctl.c: don't copy back the result for -ENOTTY

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Message-ID: <lsq.1519831218.186100743@decadent.org.uk>
Date:   Wed, 28 Feb 2018 15:20:18 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Hans Verkuil" <hans.verkuil@...co.com>,
        "Mauro Carvalho Chehab" <mchehab@...pensource.com>,
        "Sakari Ailus" <sakari.ailus@...ux.intel.com>
Subject: [PATCH 3.16 240/254] media: v4l2-ioctl.c: don't copy back the 
 result for -ENOTTY

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

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

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/v4l2-core/v4l2-ioctl.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 16bffd851bf9..e2f71def945a 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2402,8 +2402,11 @@ 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);