net: consolidate and fix ethtool_ops->get_settings calling

This patch does several things:
- introduces __ethtool_get_settings which is called from ethtool code and
  from drivers as well. Put ASSERT_RTNL there.
- dev_ethtool_get_settings() is replaced by __ethtool_get_settings()
- changes calling in drivers so rtnl locking is respected. In
  iboe_get_rate was previously ->get_settings() called unlocked. This
  fixes it. Also prb_calc_retire_blk_tmo() in af_packet.c had the same
  problem. Also fixed by calling __dev_get_by_index() instead of
  dev_get_by_index() and holding rtnl_lock for both calls.
- introduces rtnl_lock in bnx2fc_vport_create() and fcoe_vport_create()
  so bnx2fc_if_create() and fcoe_if_create() are called locked as they
  are from other places.
- use __ethtool_get_settings() in bonding code

Signed-off-by: Jiri Pirko <jpirko@redhat.com>

v2->v3:
	-removed dev_ethtool_get_settings()
	-added ASSERT_RTNL into __ethtool_get_settings()
	-prb_calc_retire_blk_tmo - use __dev_get_by_index() and lock
	 around it and __ethtool_get_settings() call
v1->v2:
        add missing export_symbol
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com> [except FCoE bits]
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -557,7 +557,7 @@ down:
 static int bond_update_speed_duplex(struct slave *slave)
 {
 	struct net_device *slave_dev = slave->dev;
-	struct ethtool_cmd etool = { .cmd = ETHTOOL_GSET };
+	struct ethtool_cmd ecmd;
 	u32 slave_speed;
 	int res;
 
@@ -565,18 +565,15 @@ static int bond_update_speed_duplex(struct slave *slave)
 	slave->speed = SPEED_100;
 	slave->duplex = DUPLEX_FULL;
 
-	if (!slave_dev->ethtool_ops || !slave_dev->ethtool_ops->get_settings)
-		return -1;
-
-	res = slave_dev->ethtool_ops->get_settings(slave_dev, &etool);
+	res = __ethtool_get_settings(slave_dev, &ecmd);
 	if (res < 0)
 		return -1;
 
-	slave_speed = ethtool_cmd_speed(&etool);
+	slave_speed = ethtool_cmd_speed(&ecmd);
 	if (slave_speed == 0 || slave_speed == ((__u32) -1))
 		return -1;
 
-	switch (etool.duplex) {
+	switch (ecmd.duplex) {
 	case DUPLEX_FULL:
 	case DUPLEX_HALF:
 		break;
@@ -585,7 +582,7 @@ static int bond_update_speed_duplex(struct slave *slave)
 	}
 
 	slave->speed = slave_speed;
-	slave->duplex = etool.duplex;
+	slave->duplex = ecmd.duplex;
 
 	return 0;
 }