net: use core MTU range checking in misc drivers

firewire-net:
- set min/max_mtu
- remove fwnet_change_mtu

nes:
- set max_mtu
- clean up nes_netdev_change_mtu

xpnet:
- set min/max_mtu
- remove xpnet_dev_change_mtu

hippi:
- set min/max_mtu
- remove hippi_change_mtu

batman-adv:
- set max_mtu
- remove batadv_interface_change_mtu
- initialization is a little async, not 100% certain that max_mtu is set
  in the optimal place, don't have hardware to test with

rionet:
- set min/max_mtu
- remove rionet_change_mtu

slip:
- set min/max_mtu
- streamline sl_change_mtu

um/net_kern:
- remove pointless ndo_change_mtu

hsi/clients/ssi_protocol:
- use core MTU range checking
- remove now redundant ssip_pn_set_mtu

ipoib:
- set a default max MTU value
- Note: ipoib's actual max MTU can vary, depending on if the device is in
  connected mode or not, so we'll just set the max_mtu value to the max
  possible, and let the ndo_change_mtu function continue to validate any new
  MTU change requests with checks for CM or not. Note that ipoib has no
  min_mtu set, and thus, the network core's mtu > 0 check is the only lower
  bounds here.

mptlan:
- use net core MTU range checking
- remove now redundant mpt_lan_change_mtu

fddi:
- min_mtu = 21, max_mtu = 4470
- remove now redundant fddi_change_mtu (including export)

fjes:
- min_mtu = 8192, max_mtu = 65536
- The max_mtu value is actually one over IP_MAX_MTU here, but the idea is to
  get past the core net MTU range checks so fjes_change_mtu can validate a
  new MTU against what it supports (see fjes_support_mtu in fjes_hw.c)

hsr:
- min_mtu = 0 (calls ether_setup, max_mtu is 1500)

f_phonet:
- min_mtu = 6, max_mtu = 65541

u_ether:
- min_mtu = 14, max_mtu = 15412

phonet/pep-gprs:
- min_mtu = 576, max_mtu = 65530
- remove redundant gprs_set_mtu

CC: [email protected]
CC: [email protected]
CC: Stefan Richter <[email protected]>
CC: Faisal Latif <[email protected]>
CC: [email protected]
CC: Cliff Whickman <[email protected]>
CC: Robin Holt <[email protected]>
CC: Jes Sorensen <[email protected]>
CC: Marek Lindner <[email protected]>
CC: Simon Wunderlich <[email protected]>
CC: Antonio Quartulli <[email protected]>
CC: Sathya Prakash <[email protected]>
CC: Chaitra P B <[email protected]>
CC: Suganath Prabu Subramani <[email protected]>
CC: [email protected]
CC: Sebastian Reichel <[email protected]>
CC: Felipe Balbi <[email protected]>
CC: Arvid Brodin <[email protected]>
CC: Remi Denis-Courmont <[email protected]>
Signed-off-by: Jarod Wilson <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

drivers/firewire/net.c

@@ -1349,15 +1349,6 @@ static netdev_tx_t fwnet_tx(struct sk_buff *skb, struct net_device *net)
 	return NETDEV_TX_OK;
 }
 
-static int fwnet_change_mtu(struct net_device *net, int new_mtu)
-{
-	if (new_mtu < 68)
-		return -EINVAL;
-
-	net->mtu = new_mtu;
-	return 0;
-}
-
 static const struct ethtool_ops fwnet_ethtool_ops = {
 	.get_link	= ethtool_op_get_link,
 };
@@ -1366,7 +1357,6 @@ static const struct net_device_ops fwnet_netdev_ops = {
 	.ndo_open       = fwnet_open,
 	.ndo_stop	= fwnet_stop,
 	.ndo_start_xmit = fwnet_tx,
-	.ndo_change_mtu = fwnet_change_mtu,
 };
 
 static void fwnet_init_dev(struct net_device *net)
@@ -1435,7 +1425,6 @@ static int fwnet_probe(struct fw_unit *unit,
 	struct net_device *net;
 	bool allocated_netdev = false;
 	struct fwnet_device *dev;
-	unsigned max_mtu;
 	int ret;
 	union fwnet_hwaddr *ha;
 
@@ -1478,9 +1467,10 @@ static int fwnet_probe(struct fw_unit *unit,
 	 * Use the RFC 2734 default 1500 octets or the maximum payload
 	 * as initial MTU
 	 */
-	max_mtu = (1 << (card->max_receive + 1))
-		  - sizeof(struct rfc2734_header) - IEEE1394_GASP_HDR_SIZE;
-	net->mtu = min(1500U, max_mtu);
+	net->max_mtu = (1 << (card->max_receive + 1))
+		       - sizeof(struct rfc2734_header) - IEEE1394_GASP_HDR_SIZE;
+	net->mtu = min(1500U, net->max_mtu);
+	net->min_mtu = ETH_MIN_MTU;
 
 	/* Set our hardware address while we're at it */
 	ha = (union fwnet_hwaddr *)net->dev_addr;