bonding: fix alb mode locking regression

Fix locking issue in alb MAC address management; removed
incorrect locking and replaced with correct locking. This bug was
introduced in commit 059fe7a578fba5bbb0fdc0365bfcf6218fa25eb0
("bonding: Convert locks to _bh, rework alb locking for new locking")

Bug reported by Paul Smith <[e-mail]>, who also
tested the fix.

Signed-off-by: Jay Vosburgh <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/bonding/bond_alb.c

···
  * Called with RTNL
  */
 int bond_alb_set_mac_address(struct net_device *bond_dev, void *addr)
-	__releases(&bond->curr_slave_lock)
-	__releases(&bond->lock)
 	__acquires(&bond->lock)
-	__acquires(&bond->curr_slave_lock)
+	__releases(&bond->lock)
 {
 	struct bonding *bond = netdev_priv(bond_dev);
 	struct sockaddr *sa = addr;
···
 		}
 	}
 
-	write_unlock_bh(&bond->curr_slave_lock);
-	read_unlock(&bond->lock);
-
 	if (swap_slave) {
 		alb_swap_mac_addr(bond, swap_slave, bond->curr_active_slave);
 		alb_fasten_mac_swap(bond, swap_slave, bond->curr_active_slave);
···
 		alb_set_slave_mac_addr(bond->curr_active_slave, bond_dev->dev_addr,
 				       bond->alb_info.rlb_enabled);
 
+		read_lock(&bond->lock);
 		alb_send_learning_packets(bond->curr_active_slave, bond_dev->dev_addr);
 		if (bond->alb_info.rlb_enabled) {
 			/* inform clients mac address has changed */
 			rlb_req_update_slave_clients(bond, bond->curr_active_slave);
 		}
+		read_unlock(&bond->lock);
 	}
-
-	read_lock(&bond->lock);
-	write_lock_bh(&bond->curr_slave_lock);
 
 	return 0;
 }