devlink: Use controller while building phys_port_name

Now that controller number attribute is available, use it when
building phsy_port_name for external controller ports.

An example devlink port and representor netdev name consist of controller
annotation for external controller with controller number = 1,
for a VF 1 of PF 0:

$ devlink port show pci/0000:06:00.0/2
pci/0000:06:00.0/2: type eth netdev ens2f0c1pf0vf1 flavour pcivf controller 1 pfnum 0 vfnum 1 external true splittable false
  function:
    hw_addr 00:00:00:00:00:00

$ devlink port show pci/0000:06:00.0/2 -jp
{
    "port": {
        "pci/0000:06:00.0/2": {
            "type": "eth",
            "netdev": "ens2f0c1pf0vf1",
            "flavour": "pcivf",
            "controller": 1,
            "pfnum": 0,
            "vfnum": 1,
            "external": true,
            "splittable": false,
            "function": {
                "hw_addr": "00:00:00:00:00:00"
            }
        }
    }
}

Controller number annotation is skipped for non external controllers to
maintain backward compatibility.
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/devlink.c

@@ -7793,9 +7793,23 @@ static int __devlink_port_phys_port_name_get(struct devlink_port *devlink_port,
 		WARN_ON(1);
 		return -EINVAL;
 	case DEVLINK_PORT_FLAVOUR_PCI_PF:
+		if (attrs->pci_pf.external) {
+			n = snprintf(name, len, "c%u", attrs->pci_pf.controller);
+			if (n >= len)
+				return -EINVAL;
+			len -= n;
+			name += n;
+		}
 		n = snprintf(name, len, "pf%u", attrs->pci_pf.pf);
 		break;
 	case DEVLINK_PORT_FLAVOUR_PCI_VF:
+		if (attrs->pci_vf.external) {
+			n = snprintf(name, len, "c%u", attrs->pci_vf.controller);
+			if (n >= len)
+				return -EINVAL;
+			len -= n;
+			name += n;
+		}
 		n = snprintf(name, len, "pf%uvf%u",
 			     attrs->pci_vf.pf, attrs->pci_vf.vf);
 		break;