Subject: [PATCH 06/53] ipvlan: fix IFLA_MTU ignored on NEWLINK

From: Xin Long <[email-masked]>
Date: Thu, 21 Jun 2018 12:56:04 +0800

[ Upstream commit 30877961b1cdd6fdca783c2e8c4f0f47e95dc58c ]

Commit 296d48568042 ("ipvlan: inherit MTU from master device") adjusted
the mtu from the master device when creating a ipvlan device, but it
would also override the mtu value set in rtnl_create_link. It causes
IFLA_MTU param not to take effect.

So this patch is to not adjust the mtu if IFLA_MTU param is set when
creating a ipvlan device.

Fixes: 296d48568042 ("ipvlan: inherit MTU from master device")
Reported-by: Jianlin Shi <[email-masked]>
Signed-off-by: Xin Long <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/net/ipvlan/ipvlan_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index 4377c26f714d..6641fd5355e0 100644
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -594,7 +594,8 @@ int ipvlan_link_new(struct net *src_net, struct net_device *dev,
 	ipvlan->phy_dev = phy_dev;
 	ipvlan->dev = dev;
 	ipvlan->sfeatures = IPVLAN_FEATURES;
-	ipvlan_adjust_mtu(ipvlan, phy_dev);
+	if (!tb[IFLA_MTU])
+		ipvlan_adjust_mtu(ipvlan, phy_dev);
 	INIT_LIST_HEAD(&ipvlan->addrs);
 	spin_lock_init(&ipvlan->addrs_lock);
 
-- 
2.17.1