thunderbolt: Fix memory leak in margining

Memory for the usb4->margining needs to be relased for the upstream port
of the router as well, even though the debugfs directory gets released
with the router device removal. Fix this.

Fixes: d0f1e0c2 ("thunderbolt: Add support for receiver lane margining")
Cc: stable@vger.kernel.org
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/debugfs.c

@@ -942,7 +942,8 @@ static void margining_port_remove(struct tb_port *port)
 
 	snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
 	parent = debugfs_lookup(dir_name, port->sw->debugfs_dir);
-	debugfs_remove_recursive(debugfs_lookup("margining", parent));
+	if (parent)
+		debugfs_remove_recursive(debugfs_lookup("margining", parent));
 
 	kfree(port->usb4->margining);
 	port->usb4->margining = NULL;
@@ -967,19 +968,18 @@ static void margining_switch_init(struct tb_switch *sw)
 
 static void margining_switch_remove(struct tb_switch *sw)
 {
+	struct tb_port *upstream, *downstream;
 	struct tb_switch *parent_sw;
-	struct tb_port *downstream;
 	u64 route = tb_route(sw);
 
 	if (!route)
 		return;
 
-	/*
-	 * Upstream is removed with the router itself but we need to
-	 * remove the downstream port margining directory.
-	 */
+	upstream = tb_upstream_port(sw);
 	parent_sw = tb_switch_parent(sw);
 	downstream = tb_port_at(route, parent_sw);
+
+	margining_port_remove(upstream);
 	margining_port_remove(downstream);
 }