net/mlx4_core: Defer VF initialization till PF is fully initialized

Fix in commit [1] is not sufficient since a deferred VF initialization
could happen after pci_enable_sriov() is finished, but before the PF is
fully initialized.
Need to prevent VFs from initializing till the PF is fully ready and
comm channel is operational.

[1] - 9798935 "net/mlx4_core: mlx4_init_slave() shouldn't access comm
      channel before PF is ready"

CC: Stuart Hayes <Stuart_Hayes@Dell.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -2369,10 +2369,10 @@ static int __mlx4_init_one(struct pci_dev *pdev, int pci_dev_data)
 			} else {
 				atomic_inc(&pf_loading);
 				err = pci_enable_sriov(pdev, total_vfs);
-				atomic_dec(&pf_loading);
 				if (err) {
 					mlx4_err(dev, "Failed to enable SR-IOV, continuing without SR-IOV (err = %d).\n",
 						 err);
+					atomic_dec(&pf_loading);
 					err = 0;
 				} else {
 					mlx4_warn(dev, "Running in master mode\n");
@@ -2532,6 +2532,9 @@ slave_start:
 
 	priv->removed = 0;
 
+	if (mlx4_is_master(dev) && dev->num_vfs)
+		atomic_dec(&pf_loading);
+
 	return 0;
 
 err_port:
@@ -2582,6 +2585,9 @@ err_rel_own:
 	if (!mlx4_is_slave(dev))
 		mlx4_free_ownership(dev);
 
+	if (mlx4_is_master(dev) && dev->num_vfs)
+		atomic_dec(&pf_loading);
+
 	kfree(priv->dev.dev_vfs);
 
 err_free_dev:
@@ -2675,6 +2681,7 @@ static void __mlx4_remove_one(struct pci_dev *pdev)
 	if (dev->flags & MLX4_FLAG_SRIOV) {
 		mlx4_warn(dev, "Disabling SR-IOV\n");
 		pci_disable_sriov(pdev);
+		dev->num_vfs = 0;
 	}
 
 	if (!mlx4_is_slave(dev))