infiniband: remove dev_base_lock use

dev_base_lock is the legacy way to lock the device list, and is planned
to disappear. (writers hold RTNL, readers hold RCU lock)

Convert rdma_translate_ip() and update_ipv6_gids() to RCU locking.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c
index bf3e20c..4e55a28 100644
--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -848,8 +848,8 @@
 		goto out;
 	}
 
-	read_lock(&dev_base_lock);
-	for_each_netdev(&init_net, tmp) {
+	rcu_read_lock();
+	for_each_netdev_rcu(&init_net, tmp) {
 		if (ndev && (tmp == ndev || rdma_vlan_dev_real_dev(tmp) == ndev)) {
 			gid.global.subnet_prefix = cpu_to_be64(0xfe80000000000000LL);
 			vid = rdma_vlan_dev_vlan_id(tmp);
@@ -884,7 +884,7 @@
 			}
 		}
 	}
-	read_unlock(&dev_base_lock);
+	rcu_read_unlock();
 
 	for (i = 0; i < 128; ++i)
 		if (!hits[i]) {