From: Xin Long <lucien.xin@gmail.com>
Date: Sun, 15 Oct 2017 18:13:41 +0800
Subject: rtnetlink: bring NETDEV_CHANGEMTU event process back in
 rtnetlink_event
Patch-mainline: v4.14-rc6
Git-commit: 8a212589fe0e45f26c549dfa271a157ca8eea1ac
References: bsc#1056787

Commit 085e1a65f04f ("rtnetlink: Do not generate notifications for MTU
events") tried to fix the redundant notifications issue when ip link
set mtu by removing NETDEV_CHANGEMTU event process in rtnetlink_event.

But it also resulted in no notification generated when dev's mtu is
changed via other methods, like:
  'ifconfig eth1 mtu 1400' or 'echo 1400 > /sys/class/net/eth1/mtu'
It would cause users not to be notified by this change.

This patch is to fix it by bringing NETDEV_CHANGEMTU event back into
rtnetlink_event, and the redundant notifications issue will be fixed
in the later patch 'rtnetlink: check DO_SETLINK_NOTIFY correctly in
do_setlink'.

Fixes: 085e1a65f04f ("rtnetlink: Do not generate notifications for MTU events")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/core/rtnetlink.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -4231,6 +4231,7 @@ static int rtnetlink_event(struct notifi
 
 	switch (event) {
 	case NETDEV_REBOOT:
+	case NETDEV_CHANGEMTU:
 	case NETDEV_CHANGEADDR:
 	case NETDEV_CHANGENAME:
 	case NETDEV_FEAT_CHANGE: