IB/mlx5: Simplify netdev unbinding

When dealing with netdev unregister events, we just need to know that this
is our currently bounded netdev. There's no need to do any further
checks/queries.

This patch doesn't change any functionality.
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -172,7 +172,6 @@ static int mlx5_netdev_event(struct notifier_block *this,
 
 	switch (event) {
 	case NETDEV_REGISTER:
-	case NETDEV_UNREGISTER:
 		write_lock(&roce->netdev_lock);
 		if (ibdev->rep) {
 			struct mlx5_eswitch *esw = ibdev->mdev->priv.eswitch;
@@ -181,15 +180,20 @@ static int mlx5_netdev_event(struct notifier_block *this,
 			rep_ndev = mlx5_ib_get_rep_netdev(esw,
 							  ibdev->rep->vport);
 			if (rep_ndev == ndev)
-				roce->netdev = (event == NETDEV_UNREGISTER) ?
-					NULL : ndev;
+				roce->netdev = ndev;
 		} else if (ndev->dev.parent == &mdev->pdev->dev) {
-			roce->netdev = (event == NETDEV_UNREGISTER) ?
-				NULL : ndev;
+			roce->netdev = ndev;
 		}
 		write_unlock(&roce->netdev_lock);
 		break;
 
+	case NETDEV_UNREGISTER:
+		write_lock(&roce->netdev_lock);
+		if (roce->netdev == ndev)
+			roce->netdev = NULL;
+		write_unlock(&roce->netdev_lock);
+		break;
+
 	case NETDEV_CHANGE:
 	case NETDEV_UP:
 	case NETDEV_DOWN: {