net/mlx4_en: Fix race when setting the device MAC address

Remove unnecessary use of workqueue for the device MAC address setting
flow, and fix a race when setting MAC address which was introduced by
commit c07cb4b0a "net/mlx4_en: Manage hash of MAC addresses per port"

The race happened when mlx4_en_replace_mac was being executed in parallel
with a successive call to ndo_set_mac_address, e.g witn an A/B/A MAC
setting configuration test, the third set fails.

With this change we also properly report an error if set MAC fails.

Signed-off-by: Yan Burman <yanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 21 insertions, 22 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index bb4d8d99f36d..217e618fd712 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -650,28 +650,10 @@ u64 mlx4_en_mac_to_u64(u8 *addr)
         return mac;
 }
 
-static int mlx4_en_set_mac(struct net_device *dev, void *addr)
+static int mlx4_en_do_set_mac(struct mlx4_en_priv *priv)
 {
-        struct mlx4_en_priv *priv = netdev_priv(dev);
-        struct mlx4_en_dev *mdev = priv->mdev;
-        struct sockaddr *saddr = addr;
-
-        if (!is_valid_ether_addr(saddr->sa_data))
-                return -EADDRNOTAVAIL;
-
-        memcpy(dev->dev_addr, saddr->sa_data, ETH_ALEN);
-        queue_work(mdev->workqueue, &priv->mac_task);
-        return 0;
-}
-
-static void mlx4_en_do_set_mac(struct work_struct *work)
-{
-        struct mlx4_en_priv *priv = container_of(work, struct mlx4_en_priv,
-                                                 mac_task);
-        struct mlx4_en_dev *mdev = priv->mdev;
         int err = 0;
 
-        mutex_lock(&mdev->state_lock);
         if (priv->port_up) {
                 /* Remove old MAC and insert the new one */
                 err = mlx4_en_replace_mac(priv, priv->base_qpn,
@@ -683,7 +665,26 @@ static void mlx4_en_do_set_mac(struct work_struct *work)
         } else
                 en_dbg(HW, priv, "Port is down while registering mac, exiting...\n");
 
+        return err;
+}
+
+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;
+        int err;
+
+        if (!is_valid_ether_addr(saddr->sa_data))
+                return -EADDRNOTAVAIL;
+
+        memcpy(dev->dev_addr, saddr->sa_data, ETH_ALEN);
+
+        mutex_lock(&mdev->state_lock);
+        err = mlx4_en_do_set_mac(priv);
         mutex_unlock(&mdev->state_lock);
+
+        return err;
 }
 
 static void mlx4_en_clear_list(struct net_device *dev)
@@ -1348,7 +1349,7 @@ 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]) {
-                queue_work(mdev->workqueue, &priv->mac_task);
+                mlx4_en_do_set_mac(priv);
                 mdev->mac_removed[MLX4_MAX_PORTS + 1 - priv->port] = 0;
         }
         mutex_unlock(&mdev->state_lock);
@@ -2078,7 +2079,6 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
         priv->msg_enable = MLX4_EN_MSG_LEVEL;
         spin_lock_init(&priv->stats_lock);
         INIT_WORK(&priv->rx_mode_task, mlx4_en_do_set_rx_mode);
-        INIT_WORK(&priv->mac_task, mlx4_en_do_set_mac);
         INIT_WORK(&priv->watchdog_task, mlx4_en_restart);
         INIT_WORK(&priv->linkstate_task, mlx4_en_linkstate);
         INIT_DELAYED_WORK(&priv->stats_task, mlx4_en_do_get_stats);
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index c313d7e943a9..f710b7ce0dcb 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -509,7 +509,6 @@ struct mlx4_en_priv {
         struct mlx4_en_cq rx_cq[MAX_RX_RINGS];
         struct mlx4_qp drop_qp;
         struct work_struct rx_mode_task;
-        struct work_struct mac_task;
         struct work_struct watchdog_task;
         struct work_struct linkstate_task;
         struct delayed_work stats_task;