net: devlink: introduce devlink_compat_phys_port_name_get()

Introduce devlink_compat_phys_port_name_get() helper that
gets the physical port name for specified netdevice
according to devlink port attributes.
Call this helper from dev_get_phys_port_name()
in case ndo_get_phys_port_name is not defined.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/devlink.h

@@ -739,6 +739,8 @@ devlink_health_reporter_state_update(struct devlink_health_reporter *reporter,
 void devlink_compat_running_version(struct net_device *dev,
 				    char *buf, size_t len);
 int devlink_compat_flash_update(struct net_device *dev, const char *file_name);
+int devlink_compat_phys_port_name_get(struct net_device *dev,
+				      char *name, size_t len);
 
 #else
 
@@ -753,6 +755,13 @@ devlink_compat_flash_update(struct net_device *dev, const char *file_name)
 	return -EOPNOTSUPP;
 }
 
+static inline int
+devlink_compat_phys_port_name_get(struct net_device *dev,
+				  char *name, size_t len)
+{
+	return -EOPNOTSUPP;
+}
+
 #endif
 
 #endif /* _NET_DEVLINK_H_ */

net/core/dev.c

@@ -146,6 +146,7 @@
 #include <net/udp_tunnel.h>
 #include <linux/net_namespace.h>
 #include <linux/indirect_call_wrapper.h>
+#include <net/devlink.h>
 
 #include "net-sysfs.h"
 
@@ -7877,10 +7878,14 @@ int dev_get_phys_port_name(struct net_device *dev,
 			   char *name, size_t len)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
+	int err;
 
-	if (!ops->ndo_get_phys_port_name)
+	if (ops->ndo_get_phys_port_name) {
-		return -EOPNOTSUPP;
+		err = ops->ndo_get_phys_port_name(dev, name, len);
-	return ops->ndo_get_phys_port_name(dev, name, len);
+		if (err != -EOPNOTSUPP)
+			return err;
+	}
+	return devlink_compat_phys_port_name_get(dev, name, len);
 }
 EXPORT_SYMBOL(dev_get_phys_port_name);
 

net/core/devlink.c

@@ -5414,8 +5414,8 @@ void devlink_port_attrs_set(struct devlink_port *devlink_port,
 }
 EXPORT_SYMBOL_GPL(devlink_port_attrs_set);
 
-int devlink_port_get_phys_port_name(struct devlink_port *devlink_port,
+static int __devlink_port_phys_port_name_get(struct devlink_port *devlink_port,
-				    char *name, size_t len)
+					     char *name, size_t len)
 {
 	struct devlink_port_attrs *attrs = &devlink_port->attrs;
 	int n = 0;
@@ -5445,6 +5445,12 @@ int devlink_port_get_phys_port_name(struct devlink_port *devlink_port,
 
 	return 0;
 }
+
+int devlink_port_get_phys_port_name(struct devlink_port *devlink_port,
+				    char *name, size_t len)
+{
+	return __devlink_port_phys_port_name_get(devlink_port, name, len);
+}
 EXPORT_SYMBOL_GPL(devlink_port_get_phys_port_name);
 
 int devlink_sb_register(struct devlink *devlink, unsigned int sb_index,
@@ -6459,6 +6465,24 @@ out:
 	return ret;
 }
 
+int devlink_compat_phys_port_name_get(struct net_device *dev,
+				      char *name, size_t len)
+{
+	struct devlink_port *devlink_port;
+
+	/* RTNL mutex is held here which ensures that devlink_port
+	 * instance cannot disappear in the middle. No need to take
+	 * any devlink lock as only permanent values are accessed.
+	 */
+	ASSERT_RTNL();
+
+	devlink_port = netdev_to_devlink_port(dev);
+	if (!devlink_port)
+		return -EOPNOTSUPP;
+
+	return __devlink_port_phys_port_name_get(devlink_port, name, len);
+}
+
 static int __init devlink_init(void)
 {
 	return genl_register_family(&devlink_nl_family);