[PATCH net v4 2/6] net: phy: unregister SFP upstream before port cleanup

[Xuanqiang Luo]

From: Xuanqiang Luo <luoxuanqiang@xxxxxxxxxx>

Commit 4497f5028675 ("net: phy: Clean the phy_ports after unregistering
the downstream SFP bus") established that an SFP upstream must be
unregistered before its phy_ports are destroyed because SFP callbacks
may access these ports.

phy_setup_ports() does not follow this order when a later port setup
step fails after phy_sfp_probe() succeeds. It destroys the SFP phy_port
and leaves phy_probe() to unregister the upstream later, creating a race
between port destruction and SFP upstream callbacks.

The error unwind is also split across three functions. If
phy_setup_sfp_port() fails, phy_sfp_probe() leaves the upstream
registered and relies on phy_probe() to remove it after
phy_setup_ports() returns.

Make each layer unwind the resources it successfully set up. Unregister
only the upstream in phy_sfp_probe() when SFP port setup fails, since
the failed port has already been destroyed. Add phy_sfp_release() for a
successful SFP probe, and make phy_setup_ports() use it before cleaning
up the remaining ports. Once phy_setup_ports() has rolled back all port
setup, make phy_probe() skip this cleanup.

Fixes: 589e934d2735 ("net: phy: Introduce PHY ports representation")
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: Xuanqiang Luo <luoxuanqiang@xxxxxxxxxx>
---
 drivers/net/phy/phy_device.c | 49 ++++++++++++++++++++++++++++--------
 1 file changed, 38 insertions(+), 11 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 2cf70471ae089..4b9b2300422fb 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1723,12 +1723,41 @@ static int phy_sfp_probe(struct phy_device *phydev)
 			phydev->sfp_bus = NULL;
 	}
 
-	if (!ret && phydev->sfp_bus)
+	if (!ret && phydev->sfp_bus) {
 		ret = phy_setup_sfp_port(phydev);
+		if (ret) {
+			sfp_bus_del_upstream(phydev->sfp_bus);
+			phydev->sfp_bus = NULL;
+		}
+	}
 
 	return ret;
 }
 
+/**
+ * phy_sfp_release - release resources set up by phy_sfp_probe()
+ * @phydev: the PHY device
+ *
+ * Release the SFP resources set up by a successful phy_sfp_probe(). Unregister
+ * the upstream before destroying its phy_port, so SFP upstream callbacks cannot
+ * race with port destruction.
+ */
+static void phy_sfp_release(struct phy_device *phydev)
+{
+	struct phy_port *port, *tmp;
+
+	sfp_bus_del_upstream(phydev->sfp_bus);
+	phydev->sfp_bus = NULL;
+
+	list_for_each_entry_safe(port, tmp, &phydev->ports, head) {
+		if (!port->is_sfp)
+			continue;
+
+		phy_del_port(phydev, port);
+		phy_port_destroy(port);
+	}
+}
+
 static bool phy_drv_supports_irq(const struct phy_driver *phydrv)
 {
 	return phydrv->config_intr && phydrv->handle_interrupt;
@@ -3547,13 +3576,13 @@ static int phy_setup_ports(struct phy_device *phydev)
 	if (!phydev->is_genphy_driven) {
 		ret = phy_sfp_probe(phydev);
 		if (ret)
-			goto out;
+			goto err_ports;
 	}
 
 	if (phydev->n_ports < phydev->max_n_ports) {
 		ret = phy_default_setup_single_port(phydev);
 		if (ret)
-			goto out;
+			goto err_sfp;
 	}
 
 	linkmode_zero(ports_supported);
@@ -3580,7 +3609,9 @@ static int phy_setup_ports(struct phy_device *phydev)
 
 	return 0;
 
-out:
+err_sfp:
+	phy_sfp_release(phydev);
+err_ports:
 	phy_cleanup_ports(phydev);
 	return ret;
 }
@@ -3744,7 +3775,7 @@ static int phy_probe(struct device *dev)
 
 	err = phy_setup_ports(phydev);
 	if (err)
-		goto out_sfp_release;
+		goto out_reset;
 
 	phy_advertise_supported(phydev);
 
@@ -3816,9 +3847,7 @@ static int phy_probe(struct device *dev)
 		phy_led_triggers_unregister(phydev);
 
 out_sfp_release:
-	sfp_bus_del_upstream(phydev->sfp_bus);
-	phydev->sfp_bus = NULL;
-
+	phy_sfp_release(phydev);
 	phy_cleanup_ports(phydev);
 
 out_reset:
@@ -3842,9 +3871,7 @@ static int phy_remove(struct device *dev)
 
 	phydev->state = PHY_DOWN;
 
-	sfp_bus_del_upstream(phydev->sfp_bus);
-	phydev->sfp_bus = NULL;
-
+	phy_sfp_release(phydev);
 	phy_cleanup_ports(phydev);
 
 	if (phydev->drv && phydev->drv->remove)
-- 
2.43.0