The phy_link_topology structure stores information about the PHY-related
components connected to a net_device. It is opportunistically allocated,
when we add the first item to the topology, as this is not relevant for
all kinds of net_devices.

In preparation for the addition of phy_port tracking in the topology,
let's make a dedicated helper for that allocation sequence.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/net/phy/phy_link_topology.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/net/phy/phy_link_topology.c b/drivers/net/phy/phy_link_topology.c
index 0e9e987f37dd..7dc2ff10c74a 100644
--- a/drivers/net/phy/phy_link_topology.c
+++ b/drivers/net/phy/phy_link_topology.c
@@ -27,21 +27,34 @@ static int netdev_alloc_phy_link_topology(struct net_device *dev)
 	return 0;
 }
 
+static struct phy_link_topology *phy_link_topo_get_or_alloc(struct net_device *dev)
+{
+	int ret;
+
+	if (dev->link_topo)
+		return dev->link_topo;
+
+	/* The topology is allocated the first time we add an object to it.
+	 * It is freed alongside the netdev.
+	 */
+	ret = netdev_alloc_phy_link_topology(dev);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return dev->link_topo;
+}
+
 int phy_link_topo_add_phy(struct net_device *dev,
 			  struct phy_device *phy,
 			  enum phy_upstream upt, void *upstream)
 {
-	struct phy_link_topology *topo = dev->link_topo;
+	struct phy_link_topology *topo;
 	struct phy_device_node *pdn;
 	int ret;
 
-	if (!topo) {
-		ret = netdev_alloc_phy_link_topology(dev);
-		if (ret)
-			return ret;
-
-		topo = dev->link_topo;
-	}
+	topo = phy_link_topo_get_or_alloc(dev);
+	if (IS_ERR(topo))
+		return PTR_ERR(topo);
 
 	pdn = kzalloc(sizeof(*pdn), GFP_KERNEL);
 	if (!pdn)
-- 
2.49.0