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>
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 6cdba5f..f444817 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -569,15 +569,25 @@
 	return 0;
 }
 
-static int ethtool_get_settings(struct net_device *dev, void __user *useraddr)
+int __ethtool_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 {
-	struct ethtool_cmd cmd = { .cmd = ETHTOOL_GSET };
-	int err;
+	ASSERT_RTNL();
 
-	if (!dev->ethtool_ops->get_settings)
+	if (!dev->ethtool_ops || !dev->ethtool_ops->get_settings)
 		return -EOPNOTSUPP;
 
-	err = dev->ethtool_ops->get_settings(dev, &cmd);
+	memset(cmd, 0, sizeof(struct ethtool_cmd));
+	cmd->cmd = ETHTOOL_GSET;
+	return dev->ethtool_ops->get_settings(dev, cmd);
+}
+EXPORT_SYMBOL(__ethtool_get_settings);
+
+static int ethtool_get_settings(struct net_device *dev, void __user *useraddr)
+{
+	int err;
+	struct ethtool_cmd cmd;
+
+	err = __ethtool_get_settings(dev, &cmd);
 	if (err < 0)
 		return err;