net/mlx4_en: Fix mac_hash database inconsistency

Using a local copy of dev_addr in mlx4_en_set_mac() to prevent dev_addr
from being modified during error flow or when dev_addr is modified in
another context (which is another problem that is being discussed over
the mailing list [1]).
Also fixing bad naming of priv->prev_mac into priv->current_mac.

[1] - http://patchwork.ozlabs.org/patch/351489/Reviewed-by: Eyal Perry <eyalpe@mellanox.com>
Signed-off-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

@@ -760,21 +760,22 @@ static int mlx4_en_replace_mac(struct mlx4_en_priv *priv, int qpn,
 	return __mlx4_replace_mac(dev, priv->port, qpn, new_mac_u64);
 }
 
-static int mlx4_en_do_set_mac(struct mlx4_en_priv *priv)
+static int mlx4_en_do_set_mac(struct mlx4_en_priv *priv,
+			      unsigned char new_mac[ETH_ALEN + 2])
 {
 	int err = 0;
 
 	if (priv->port_up) {
 		/* Remove old MAC and insert the new one */
 		err = mlx4_en_replace_mac(priv, priv->base_qpn,
-					  priv->dev->dev_addr, priv->prev_mac);
+					  new_mac, priv->current_mac);
 		if (err)
 			en_err(priv, "Failed changing HW MAC address\n");
 	} else
 		en_dbg(HW, priv, "Port is down while registering mac, exiting...\n");
 
-	memcpy(priv->prev_mac, priv->dev->dev_addr,
-	       sizeof(priv->prev_mac));
+	if (!err)
+		memcpy(priv->current_mac, new_mac, sizeof(priv->current_mac));
 
 	return err;
 }
@@ -784,14 +785,17 @@ static int mlx4_en_set_mac(struct net_device *dev, void *addr)
 	struct mlx4_en_priv *priv = netdev_priv(dev);
 	struct mlx4_en_dev *mdev = priv->mdev;
 	struct sockaddr *saddr = addr;
+	unsigned char new_mac[ETH_ALEN + 2];
 	int err;
 
 	if (!is_valid_ether_addr(saddr->sa_data))
 		return -EADDRNOTAVAIL;
 
 	mutex_lock(&mdev->state_lock);
-	memcpy(dev->dev_addr, saddr->sa_data, ETH_ALEN);
-	err = mlx4_en_do_set_mac(priv);
+	memcpy(new_mac, saddr->sa_data, ETH_ALEN);
+	err = mlx4_en_do_set_mac(priv, new_mac);
+	if (!err)
+		memcpy(dev->dev_addr, saddr->sa_data, ETH_ALEN);
 	mutex_unlock(&mdev->state_lock);
 
 	return err;
@@ -1156,7 +1160,8 @@ static void mlx4_en_do_uc_filter(struct mlx4_en_priv *priv,
 			}
 
 			/* MAC address of the port is not in uc list */
-			if (ether_addr_equal_64bits(entry->mac, dev->dev_addr))
+			if (ether_addr_equal_64bits(entry->mac,
+						    priv->current_mac))
 				found = true;
 
 			if (!found) {
@@ -1466,7 +1471,7 @@ static void mlx4_en_do_get_stats(struct work_struct *work)
 		queue_delayed_work(mdev->workqueue, &priv->stats_task, STATS_DELAY);
 	}
 	if (mdev->mac_removed[MLX4_MAX_PORTS + 1 - priv->port]) {
-		mlx4_en_do_set_mac(priv);
+		mlx4_en_do_set_mac(priv, priv->current_mac);
 		mdev->mac_removed[MLX4_MAX_PORTS + 1 - priv->port] = 0;
 	}
 	mutex_unlock(&mdev->state_lock);
@@ -2524,7 +2529,7 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 		}
 	}
 
-	memcpy(priv->prev_mac, dev->dev_addr, sizeof(priv->prev_mac));
+	memcpy(priv->current_mac, dev->dev_addr, sizeof(priv->current_mac));
 
 	priv->stride = roundup_pow_of_two(sizeof(struct mlx4_en_rx_desc) +
 					  DS_SIZE * MLX4_EN_MAX_RX_FRAGS);

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

@@ -530,7 +530,7 @@ struct mlx4_en_priv {
 	int registered;
 	int allocated;
 	int stride;
-	unsigned char prev_mac[ETH_ALEN + 2];
+	unsigned char current_mac[ETH_ALEN + 2];
 	int mac_index;
 	unsigned max_mtu;
 	int base_qpn;