From 4f5f85e9a70e13c8919e26609914253d18fbf858 Mon Sep 17 00:00:00 2001
From: Guillaume Nault <g.nault@alphalink.fr>
Date: Fri, 10 Aug 2018 13:22:03 +0200
Subject: [PATCH] l2tp: let pppol2tp_ioctl() fallback to dev_ioctl()

Return -ENOIOCTLCMD for unknown ioctl commands. This lets dev_ioctl()
handle generic socket ioctls like SIOCGIFNAME or SIOCGIFINDEX.
PF_PPPOX/PX_PROTO_OL2TP was one of the few socket types not honouring
this mechanism.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/l2tp/l2tp_ppp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index e2eea60bf875..62f2d3f1e431 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -1137,7 +1137,7 @@ static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
 		break;
 
 	default:
-		return -ENOSYS;
+		return -ENOIOCTLCMD;
 	}
 
 	return 0;