IB/mlx5: Avoid load failure due to unknown link width

If the firmware reports a connection width that is not 1x, 4x, 8x or 12x
it causes the driver to fail during initialization.

To prevent this failure every time a new width is introduced to the RDMA
stack, we will set a default 4x width for these widths which ar unknown to
the driver.

This is needed to allow to run old kernels with new firmware.

Cc: <stable@vger.kernel.org> # 4.1
Fixes: 1b5daf11b015 ("IB/mlx5: Avoid using the MAD_IFC command under ISSI > 0 mode")
Signed-off-by: Michael Guralnik <michaelgur@mellanox.com>
Reviewed-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -1094,31 +1094,26 @@ enum mlx5_ib_width {
 	MLX5_IB_WIDTH_12X	= 1 << 4
 };
 
-static int translate_active_width(struct ib_device *ibdev, u8 active_width,
+static void translate_active_width(struct ib_device *ibdev, u8 active_width,
 				  u8 *ib_width)
 {
 	struct mlx5_ib_dev *dev = to_mdev(ibdev);
-	int err = 0;
 
-	if (active_width & MLX5_IB_WIDTH_1X) {
+	if (active_width & MLX5_IB_WIDTH_1X)
 		*ib_width = IB_WIDTH_1X;
-	} else if (active_width & MLX5_IB_WIDTH_2X) {
-		mlx5_ib_dbg(dev, "active_width %d is not supported by IB spec\n",
-			    (int)active_width);
-		err = -EINVAL;
-	} else if (active_width & MLX5_IB_WIDTH_4X) {
+	else if (active_width & MLX5_IB_WIDTH_4X)
 		*ib_width = IB_WIDTH_4X;
-	} else if (active_width & MLX5_IB_WIDTH_8X) {
+	else if (active_width & MLX5_IB_WIDTH_8X)
 		*ib_width = IB_WIDTH_8X;
-	} else if (active_width & MLX5_IB_WIDTH_12X) {
+	else if (active_width & MLX5_IB_WIDTH_12X)
 		*ib_width = IB_WIDTH_12X;
-	} else {
-		mlx5_ib_dbg(dev, "Invalid active_width %d\n",
+	else {
+		mlx5_ib_dbg(dev, "Invalid active_width %d, setting width to default value: 4x\n",
 			    (int)active_width);
-		err = -EINVAL;
+		*ib_width = IB_WIDTH_4X;
 	}
 
-	return err;
+	return;
 }
 
 static int mlx5_mtu_to_ib_mtu(int mtu)
@@ -1225,10 +1220,8 @@ static int mlx5_query_hca_port(struct ib_device *ibdev, u8 port,
 	if (err)
 		goto out;
 
-	err = translate_active_width(ibdev, ib_link_width_oper,
-				     &props->active_width);
-	if (err)
-		goto out;
+	translate_active_width(ibdev, ib_link_width_oper, &props->active_width);
+
 	err = mlx5_query_port_ib_proto_oper(mdev, &props->active_speed, port);
 	if (err)
 		goto out;