net, team, bonding: Add netdev_base_features helper

Both bonding and team driver have logic to derive the base feature
flags before iterating over their slave devices to refine the set
via netdev_increment_features().

Add a small helper netdev_base_features() so this can be reused
instead of having it open-coded multiple times.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Cc: Ido Schimmel <idosch@idosch.org>
Cc: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241210141245.327886-1-daniel@iogearbox.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: borkmann

drivers/net/bonding/bond_main.c

@@ -1520,9 +1520,7 @@ static netdev_features_t bond_fix_features(struct net_device *dev,
 	struct slave *slave;
 
 	mask = features;
-
-	features &= ~NETIF_F_ONE_FOR_ALL;
-	features |= NETIF_F_ALL_FOR_ALL;
+	features = netdev_base_features(features);
 
 	bond_for_each_slave(bond, slave, iter) {
 		features = netdev_increment_features(features,

drivers/net/team/team_core.c

@@ -2011,8 +2011,7 @@ static netdev_features_t team_fix_features(struct net_device *dev,
 	netdev_features_t mask;
 
 	mask = features;
-	features &= ~NETIF_F_ONE_FOR_ALL;
-	features |= NETIF_F_ALL_FOR_ALL;
+	features = netdev_base_features(features);
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(port, &team->port_list, list) {

include/linux/netdev_features.h

@@ -253,4 +253,11 @@ static inline int find_next_netdev_feature(u64 feature, unsigned long start)
 				 NETIF_F_GSO_UDP_TUNNEL |		\
 				 NETIF_F_GSO_UDP_TUNNEL_CSUM)
 
+static inline netdev_features_t netdev_base_features(netdev_features_t features)
+{
+	features &= ~NETIF_F_ONE_FOR_ALL;
+	features |= NETIF_F_ALL_FOR_ALL;
+	return features;
+}
+
 #endif	/* _LINUX_NETDEV_FEATURES_H */