bonding: add ESP offload features when slaves support

Add NETIF_F_GSO_ESP bit to bond's gso_partial_features if all slaves
support it, such that ESP segmentation is handled by hardware if possible.

Signed-off-by: Jianbo Liu <[e-mail]>
Reviewed-by: Boris Pismenny <[e-mail]>
Signed-off-by: Tariq Toukan <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/bonding/bond_main.c

···
 {
 	unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE |
 					IFF_XMIT_DST_RELEASE_PERM;
+	netdev_features_t gso_partial_features = NETIF_F_GSO_ESP;
 	netdev_features_t vlan_features = BOND_VLAN_FEATURES;
 	netdev_features_t enc_features  = BOND_ENC_FEATURES;
 #ifdef CONFIG_XFRM_OFFLOAD
···
 							  BOND_XFRM_FEATURES);
 #endif /* CONFIG_XFRM_OFFLOAD */
 
+		if (slave->dev->hw_enc_features & NETIF_F_GSO_PARTIAL)
+			gso_partial_features &= slave->dev->gso_partial_features;
+
 		mpls_features = netdev_increment_features(mpls_features,
 							  slave->dev->mpls_features,
 							  BOND_MPLS_FEATURES);
···
 		tso_max_segs = min(tso_max_segs, slave->dev->tso_max_segs);
 	}
 	bond_dev->hard_header_len = max_hard_header_len;
+
+	if (gso_partial_features & NETIF_F_GSO_ESP)
+		bond_dev->gso_partial_features |= NETIF_F_GSO_ESP;
+	else
+		bond_dev->gso_partial_features &= ~NETIF_F_GSO_ESP;
 
 done:
 	bond_dev->vlan_features = vlan_features;