team: don't traverse port list using rcu in team_set_mac_address

commit 9215f437 upstream.

Currently the list is traversed using rcu variant. That is not correct
since dev_set_mac_address can be called which eventually calls
rtmsg_ifinfo_build_skb and there, skb allocation can sleep. So fix this
by remove the rcu usage here.

Fixes: 3d249d4c "net: introduce ethernet teaming device"
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/net/team/team.c

@@ -1715,11 +1715,11 @@ static int team_set_mac_address(struct net_device *dev, void *p)
 	if (dev->type == ARPHRD_ETHER && !is_valid_ether_addr(addr->sa_data))
 		return -EADDRNOTAVAIL;
 	memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
-	rcu_read_lock();
-	list_for_each_entry_rcu(port, &team->port_list, list)
+	mutex_lock(&team->lock);
+	list_for_each_entry(port, &team->port_list, list)
 		if (team->ops.port_change_dev_addr)
 			team->ops.port_change_dev_addr(team, port);
-	rcu_read_unlock();
+	mutex_unlock(&team->lock);
 	return 0;
 }