net: use core MTU range checking in core net infra

geneve:
- Merge __geneve_change_mtu back into geneve_change_mtu, set max_mtu
- This one isn't quite as straight-forward as others, could use some
  closer inspection and testing

macvlan:
- set min/max_mtu

tun:
- set min/max_mtu, remove tun_net_change_mtu

vxlan:
- Merge __vxlan_change_mtu back into vxlan_change_mtu
- Set max_mtu to IP_MAX_MTU and retain dynamic MTU range checks in
  change_mtu function
- This one is also not as straight-forward and could use closer inspection
  and testing from vxlan folks

bridge:
- set max_mtu of IP_MAX_MTU and retain dynamic MTU range checks in
  change_mtu function

openvswitch:
- set min/max_mtu, remove internal_dev_change_mtu
- note: max_mtu wasn't checked previously, it's been set to 65535, which
  is the largest possible size supported

sch_teql:
- set min/max_mtu (note: max_mtu previously unchecked, used max of 65535)

macsec:
- min_mtu = 0, max_mtu = 65535

macvlan:
- min_mtu = 0, max_mtu = 65535

ntb_netdev:
- min_mtu = 0, max_mtu = 65535

veth:
- min_mtu = 68, max_mtu = 65535

8021q:
- min_mtu = 0, max_mtu = 65535

CC: netdev@vger.kernel.org
CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
CC: Hannes Frederic Sowa <hannes@stressinduktion.org>
CC: Tom Herbert <tom@herbertland.com>
CC: Daniel Borkmann <daniel@iogearbox.net>
CC: Alexander Duyck <alexander.h.duyck@intel.com>
CC: Paolo Abeni <pabeni@redhat.com>
CC: Jiri Benc <jbenc@redhat.com>
CC: WANG Cong <xiyou.wangcong@gmail.com>
CC: Roopa Prabhu <roopa@cumulusnetworks.com>
CC: Pravin B Shelar <pshelar@ovn.org>
CC: Sabrina Dubroca <sd@queasysnail.net>
CC: Patrick McHardy <kaber@trash.net>
CC: Stephen Hemminger <stephen@networkplumber.org>
CC: Pravin Shelar <pshelar@nicira.com>
CC: Maxim Krasnyansky <maxk@qti.qualcomm.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/8021q/vlan_dev.c

@@ -826,5 +826,8 @@ void vlan_setup(struct net_device *dev)
 	dev->destructor		= vlan_dev_free;
 	dev->ethtool_ops	= &vlan_ethtool_ops;
 
+	dev->min_mtu		= 0;
+	dev->max_mtu		= ETH_MAX_MTU;
+
 	eth_zero_addr(dev->broadcast);
 }

net/bridge/br_device.c

@@ -185,7 +185,7 @@ static struct rtnl_link_stats64 *br_get_stats64(struct net_device *dev,
 static int br_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct net_bridge *br = netdev_priv(dev);
-	if (new_mtu < 68 || new_mtu > br_min_mtu(br))
+	if (new_mtu > br_min_mtu(br))
 		return -EINVAL;
 
 	dev->mtu = new_mtu;
@@ -410,6 +410,7 @@ void br_dev_setup(struct net_device *dev)
 	br->bridge_hello_time = br->hello_time = 2 * HZ;
 	br->bridge_forward_delay = br->forward_delay = 15 * HZ;
 	br->ageing_time = BR_DEFAULT_AGEING_TIME;
+	dev->max_mtu = ETH_MAX_MTU;
 
 	br_netfilter_rtable_init(br);
 	br_stp_timer_init(br);

net/openvswitch/vport-internal_dev.c

@@ -89,15 +89,6 @@ static const struct ethtool_ops internal_dev_ethtool_ops = {
 	.get_link	= ethtool_op_get_link,
 };
 
-static int internal_dev_change_mtu(struct net_device *netdev, int new_mtu)
-{
-	if (new_mtu < 68)
-		return -EINVAL;
-
-	netdev->mtu = new_mtu;
-	return 0;
-}
-
 static void internal_dev_destructor(struct net_device *dev)
 {
 	struct vport *vport = ovs_internal_dev_get_vport(dev);
@@ -148,7 +139,6 @@ static const struct net_device_ops internal_dev_netdev_ops = {
 	.ndo_stop = internal_dev_stop,
 	.ndo_start_xmit = internal_dev_xmit,
 	.ndo_set_mac_address = eth_mac_addr,
-	.ndo_change_mtu = internal_dev_change_mtu,
 	.ndo_get_stats64 = internal_get_stats,
 	.ndo_set_rx_headroom = internal_set_rx_headroom,
 };

net/sched/sch_teql.c

@@ -418,9 +418,6 @@ static int teql_master_mtu(struct net_device *dev, int new_mtu)
 	struct teql_master *m = netdev_priv(dev);
 	struct Qdisc *q;
 
-	if (new_mtu < 68)
-		return -EINVAL;
-
 	q = m->slaves;
 	if (q) {
 		do {
@@ -460,6 +457,8 @@ static __init void teql_master_setup(struct net_device *dev)
 	dev->netdev_ops =       &teql_netdev_ops;
 	dev->type		= ARPHRD_VOID;
 	dev->mtu		= 1500;
+	dev->min_mtu		= 68;
+	dev->max_mtu		= 65535;
 	dev->tx_queue_len	= 100;
 	dev->flags		= IFF_NOARP;
 	dev->hard_header_len	= LL_MAX_HEADER;