net: bonding: Inherit MPLS features from slave devices

When setting the bonding interface net device features,
the kernel code doesn't address the slaves' MPLS features
and doesn't inherit them.

Therefore, HW offloads that enhance performance such as
checksumming and TSO are disabled for MPLS tagged traffic
flowing via the bonding interface.

The patch add the inheritance of the MPLS features from the
slave devices with a similar logic to setting the bonding device's
VLAN and encapsulation features.

CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Veaceslav Falico <vfalico@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -1077,12 +1077,16 @@ static netdev_features_t bond_fix_features(struct net_device *dev,
 #define BOND_ENC_FEATURES	(NETIF_F_HW_CSUM | NETIF_F_SG | \
 				 NETIF_F_RXCSUM | NETIF_F_ALL_TSO)
 
+#define BOND_MPLS_FEATURES	(NETIF_F_HW_CSUM | NETIF_F_SG | \
+				 NETIF_F_ALL_TSO)
+
 static void bond_compute_features(struct bonding *bond)
 {
 	unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE |
 					IFF_XMIT_DST_RELEASE_PERM;
 	netdev_features_t vlan_features = BOND_VLAN_FEATURES;
 	netdev_features_t enc_features  = BOND_ENC_FEATURES;
+	netdev_features_t mpls_features  = BOND_MPLS_FEATURES;
 	struct net_device *bond_dev = bond->dev;
 	struct list_head *iter;
 	struct slave *slave;
@@ -1093,6 +1097,7 @@ static void bond_compute_features(struct bonding *bond)
 	if (!bond_has_slaves(bond))
 		goto done;
 	vlan_features &= NETIF_F_ALL_FOR_ALL;
+	mpls_features &= NETIF_F_ALL_FOR_ALL;
 
 	bond_for_each_slave(bond, slave, iter) {
 		vlan_features = netdev_increment_features(vlan_features,
@@ -1101,6 +1106,11 @@ static void bond_compute_features(struct bonding *bond)
 		enc_features = netdev_increment_features(enc_features,
 							 slave->dev->hw_enc_features,
 							 BOND_ENC_FEATURES);
+
+		mpls_features = netdev_increment_features(mpls_features,
+							  slave->dev->mpls_features,
+							  BOND_MPLS_FEATURES);
+
 		dst_release_flag &= slave->dev->priv_flags;
 		if (slave->dev->hard_header_len > max_hard_header_len)
 			max_hard_header_len = slave->dev->hard_header_len;
@@ -1114,6 +1124,7 @@ static void bond_compute_features(struct bonding *bond)
 	bond_dev->vlan_features = vlan_features;
 	bond_dev->hw_enc_features = enc_features | NETIF_F_GSO_ENCAP_ALL |
 				    NETIF_F_GSO_UDP_L4;
+	bond_dev->mpls_features = mpls_features;
 	bond_dev->gso_max_segs = gso_max_segs;
 	netif_set_gso_max_size(bond_dev, gso_max_size);