netdev: Add netdev->addr_list_lock protection.

Add netif_addr_{lock,unlock}{,_bh}() helpers.

Use them to protect operations that operate on or read
the network device unicast and multicast address lists.

Also use them in cases where the code simply wants to
block calls into the driver's ->set_rx_mode() and
->set_multicast_list() methods.

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wireless/libertas/main.c

@@ -594,6 +594,7 @@ static int lbs_add_mcast_addrs(struct cmd_ds_mac_multicast_adr *cmd,
 		return nr_addrs;
 
 	netif_tx_lock_bh(dev);
+	netif_addr_lock(dev);
 	for (mc_list = dev->mc_list; mc_list; mc_list = mc_list->next) {
 		if (mac_in_list(cmd->maclist, nr_addrs, mc_list->dmi_addr)) {
 			lbs_deb_net("mcast address %s:%s skipped\n", dev->name,
@@ -608,6 +609,7 @@ static int lbs_add_mcast_addrs(struct cmd_ds_mac_multicast_adr *cmd,
 			    print_mac(mac, mc_list->dmi_addr));
 		i++;
 	}
+	netif_addr_unlock(dev);
 	netif_tx_unlock_bh(dev);
 	if (mc_list)
 		return -EOVERFLOW;