[PATCH net-next v2 1/2] devlink: don't crash if netdev is NULL

[Jakub Kicinski]

Following change will add support for a corner case where
we may not have a netdev to pass to devlink_port_type_eth_set()
but we still want to set port type.

This is definitely a corner case, and drivers should not normally
pass NULL netdev - print a warning message when this happens.

Sadly for other port types (ib) switches don't have a device
reference, the way we always do for Ethernet, so we can't put
the warning in __devlink_port_type_set().

Signed-off-by: Jakub Kicinski <k...@kernel.org>
---
 net/core/devlink.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 49e911c19881..31cac8365b22 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -7603,14 +7603,8 @@ static void __devlink_port_type_set(struct devlink_port 
*devlink_port,
        devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
 }
 
-/**
- *     devlink_port_type_eth_set - Set port type to Ethernet
- *
- *     @devlink_port: devlink port
- *     @netdev: related netdevice
- */
-void devlink_port_type_eth_set(struct devlink_port *devlink_port,
-                              struct net_device *netdev)
+static void devlink_port_type_netdev_checks(struct devlink_port *devlink_port,
+                                           struct net_device *netdev)
 {
        const struct net_device_ops *ops = netdev->netdev_ops;
 
@@ -7644,6 +7638,24 @@ void devlink_port_type_eth_set(struct devlink_port 
*devlink_port,
                err = ops->ndo_get_port_parent_id(netdev, &ppid);
                WARN_ON(err != -EOPNOTSUPP);
        }
+}
+
+/**
+ *     devlink_port_type_eth_set - Set port type to Ethernet
+ *
+ *     @devlink_port: devlink port
+ *     @netdev: related netdevice
+ */
+void devlink_port_type_eth_set(struct devlink_port *devlink_port,
+                              struct net_device *netdev)
+{
+       if (netdev)
+               devlink_port_type_netdev_checks(devlink_port, netdev);
+       else
+               dev_warn(devlink_port->devlink->dev,
+                        "devlink port type for port %d set to Ethernet without 
a software interface reference, device type not supported by the kernel?\n",
+                        devlink_port->index);
+
        __devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_ETH, netdev);
 }
 EXPORT_SYMBOL_GPL(devlink_port_type_eth_set);
-- 
2.26.2