Let phylink handle the phy_port for PHY-less modules, and register it to
the topology.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/net/phy/phylink.c | 71 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 69 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 310af33d49a0..21af1dffa837 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -96,6 +96,7 @@ struct phylink {
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(sfp_support);
 	u8 sfp_port;
 	struct phy_port *sfp_bus_port;
+	struct phy_port *mod_port;
 
 	struct eee_config eee_cfg;
 
@@ -1786,13 +1787,31 @@ static int phylink_create_sfp_port(struct phylink *pl)
 	else
 		pl->sfp_bus_port = port;
 
+	if (pl->mod_port) {
+		ret = phy_link_topo_add_port(pl->netdev, pl->mod_port);
+		if (ret)
+			goto out_bus_port;
+	}
+
+	return 0;
+out_bus_port:
+	phy_link_topo_del_port(pl->netdev, port);
+	phy_port_destroy(port);
 	return ret;
 }
 
 static void phylink_destroy_sfp_port(struct phylink *pl)
 {
-	if (pl->netdev && pl->sfp_bus_port)
-		phy_link_topo_del_port(pl->netdev, pl->sfp_bus_port);
+	if (pl->netdev) {
+		if (pl->sfp_bus_port)
+			phy_link_topo_del_port(pl->netdev, pl->sfp_bus_port);
+
+		/* Only remove it from the topology, it will be destroyed at
+		 * module removal.
+		 */
+		if (pl->mod_port)
+			phy_link_topo_del_port(pl->netdev, pl->mod_port);
+	}
 
 	if (pl->sfp_bus_port)
 		phy_port_destroy(pl->sfp_bus_port);
@@ -3998,6 +4017,52 @@ static void phylink_sfp_disconnect_phy(void *upstream,
 	phylink_disconnect_phy(upstream);
 }
 
+static int phylink_sfp_connect_nophy(void *upstream)
+{
+	const struct sfp_module_caps *caps;
+	struct phylink *pl = upstream;
+	struct phy_port *port;
+	int ret = 0;
+
+	if (!pl->sfp_bus_port)
+		return 0;
+
+	/* Create mod port */
+	port = phy_port_alloc();
+	if (!port)
+		return -ENOMEM;
+
+	port->active = true;
+
+	caps = sfp_get_module_caps(pl->sfp_bus);
+
+	phy_caps_linkmode_filter_ifaces(port->supported, caps->link_modes,
+					pl->sfp_bus_port->interfaces);
+
+	if (pl->netdev) {
+		ret = phy_link_topo_add_port(pl->netdev, port);
+		if (ret) {
+			phy_port_destroy(port);
+			return ret;
+		}
+	}
+
+	pl->mod_port = port;
+
+	return 0;
+}
+
+static void phylink_sfp_disconnect_nophy(void *upstream)
+{
+	struct phylink *pl = upstream;
+
+	if (pl->netdev)
+		phy_link_topo_del_port(pl->netdev, pl->mod_port);
+
+	phy_port_destroy(pl->mod_port);
+	pl->mod_port = NULL;
+}
+
 static const struct sfp_upstream_ops sfp_phylink_ops = {
 	.attach = phylink_sfp_attach,
 	.detach = phylink_sfp_detach,
@@ -4009,6 +4074,8 @@ static const struct sfp_upstream_ops sfp_phylink_ops = {
 	.link_down = phylink_sfp_link_down,
 	.connect_phy = phylink_sfp_connect_phy,
 	.disconnect_phy = phylink_sfp_disconnect_phy,
+	.connect_nophy = phylink_sfp_connect_nophy,
+	.disconnect_nophy = phylink_sfp_disconnect_nophy,
 };
 
 /* Helpers for MAC drivers */
-- 
2.49.0

This is an AI-generated review of your patch. The human sending this
email has considered the AI review valid, or at least plausible.

For local reproduction steps see https://netdev-ai.bots.linux.dev/ai-local.html
---
net: phylink: Represent PHY-less SFP modules with phy_port

This patch adds support for representing PHY-less SFP modules using
phy_port by implementing connect_nophy and disconnect_nophy callbacks
for phylink.

> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
> index 310af33d49a0..21af1dffa837 100644

[ ... ]

> +static int phylink_sfp_connect_nophy(void *upstream)
> +{
> +	const struct sfp_module_caps *caps;
> +	struct phylink *pl = upstream;
> +	struct phy_port *port;
> +	int ret = 0;
> +
> +	if (!pl->sfp_bus_port)
> +		return 0;

This early return guards against sfp_bus_port being NULL, which prevents
mod_port from being allocated in that case.

> +
> +	/* Create mod port */
> +	port = phy_port_alloc();

[ ... ]

> +	pl->mod_port = port;
> +
> +	return 0;
> +}
> +
> +static void phylink_sfp_disconnect_nophy(void *upstream)
> +{
> +	struct phylink *pl = upstream;
> +
> +	if (pl->netdev)
> +		phy_link_topo_del_port(pl->netdev, pl->mod_port);
                                                     ^^^^^^^^^

Can pl->mod_port be NULL here? Looking at the SFP state machine in
sfp.c, sfp_module_disconnect_nophy() is called from the global cleanup
block when !sfp->mod_phy. This cleanup runs whenever the state machine
is not in SFP_S_DOWN and the module state changes.

If the module is removed while the state machine is in an early state
like SFP_S_WAIT or SFP_S_INIT (before PHY probing completes),
sfp_module_disconnect_nophy() will be called even though
phylink_sfp_connect_nophy() was never invoked. In that case, pl->mod_port
is still NULL.

The phy_link_topo_del_port() function dereferences port->id without a
NULL check, which would cause a NULL pointer dereference.

Should this check for pl->mod_port before calling phy_link_topo_del_port,
similar to how phylink_destroy_sfp_port() does?

> +
> +	phy_port_destroy(pl->mod_port);
> +	pl->mod_port = NULL;
> +}