net/mlx4_core: Fixed memory leak and incorrect refcount in mlx4_load_one

The current mlx4_load_one has a memory leak as it always allocates
dev_cap, but frees it only on error.

In addition, even if VFs exist when mlx4_load_one is called,
we still need to notify probed VFs that we're loading (by
incrementing pf_loading).

Fixes: a0eacca9 ('net/mlx4_core: Refactor mlx4_load_one')
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -2488,29 +2488,30 @@ static u64 mlx4_enable_sriov(struct mlx4_dev *dev, struct pci_dev *pdev,
 			     u8 total_vfs, int existing_vfs)
 {
 	u64 dev_flags = dev->flags;
-
-	dev->dev_vfs = kzalloc(
-			total_vfs * sizeof(*dev->dev_vfs),
-			GFP_KERNEL);
-	if (NULL == dev->dev_vfs) {
-		mlx4_err(dev, "Failed to allocate memory for VFs\n");
-		goto disable_sriov;
-	} else if (!(dev->flags &  MLX4_FLAG_SRIOV)) {
 	int err = 0;
 
 	atomic_inc(&pf_loading);
-		if (existing_vfs) {
-			if (existing_vfs != total_vfs)
+	if (dev->flags &  MLX4_FLAG_SRIOV) {
+		if (existing_vfs != total_vfs) {
 			mlx4_err(dev, "SR-IOV was already enabled, but with num_vfs (%d) different than requested (%d)\n",
 				 existing_vfs, total_vfs);
-		} else {
+			total_vfs = existing_vfs;
+		}
+	}
+
+	dev->dev_vfs = kzalloc(total_vfs * sizeof(*dev->dev_vfs), GFP_KERNEL);
+	if (NULL == dev->dev_vfs) {
+		mlx4_err(dev, "Failed to allocate memory for VFs\n");
+		goto disable_sriov;
+	}
+
+	if (!(dev->flags &  MLX4_FLAG_SRIOV)) {
 		mlx4_warn(dev, "Enabling SR-IOV with %d VFs\n", total_vfs);
 		err = pci_enable_sriov(pdev, total_vfs);
 	}
 	if (err) {
 		mlx4_err(dev, "Failed to enable SR-IOV, continuing without SR-IOV (err = %d)\n",
 			 err);
-			atomic_dec(&pf_loading);
 		goto disable_sriov;
 	} else {
 		mlx4_warn(dev, "Running in master mode\n");
@@ -2519,10 +2520,10 @@ static u64 mlx4_enable_sriov(struct mlx4_dev *dev, struct pci_dev *pdev,
 		dev_flags &= ~MLX4_FLAG_SLAVE;
 		dev->num_vfs = total_vfs;
 	}
-	}
 	return dev_flags;
 
 disable_sriov:
+	atomic_dec(&pf_loading);
 	dev->num_vfs = 0;
 	kfree(dev->dev_vfs);
 	return dev_flags & ~MLX4_FLAG_MASTER;
@@ -2606,8 +2607,10 @@ static int mlx4_load_one(struct pci_dev *pdev, int pci_dev_data,
 		}
 
 		if (total_vfs) {
-			existing_vfs = pci_num_vf(pdev);
 			dev->flags = MLX4_FLAG_MASTER;
+			existing_vfs = pci_num_vf(pdev);
+			if (existing_vfs)
+				dev->flags |= MLX4_FLAG_SRIOV;
 			dev->num_vfs = total_vfs;
 		}
 	}
@@ -2643,6 +2646,7 @@ static int mlx4_load_one(struct pci_dev *pdev, int pci_dev_data,
 	}
 
 	if (mlx4_is_master(dev)) {
+		/* when we hit the goto slave_start below, dev_cap already initialized */
 		if (!dev_cap) {
 			dev_cap = kzalloc(sizeof(*dev_cap), GFP_KERNEL);
 
@@ -2849,6 +2853,7 @@ static int mlx4_load_one(struct pci_dev *pdev, int pci_dev_data,
 	if (mlx4_is_master(dev) && dev->num_vfs)
 		atomic_dec(&pf_loading);
 
+	kfree(dev_cap);
 	return 0;
 
 err_port: