bonding: Correctly support GSO ESP offload

JIRA: https://issues.redhat.com/browse/RHEL-75544

commit 9e6c4e6
Author: Cosmin Ratiu <cratiu@nvidia.com>
Date:   Mon Jan 27 12:41:47 2025 +0200

    bonding: Correctly support GSO ESP offload

    The referenced fix is incomplete. It correctly computes
    bond_dev->gso_partial_features across slaves, but unfortunately
    netdev_fix_features discards gso_partial_features from the feature set
    if NETIF_F_GSO_PARTIAL isn't set in bond_dev->features.

    This is visible with ethtool -k bond0 | grep esp:
    tx-esp-segmentation: off [requested on]
    esp-hw-offload: on
    esp-tx-csum-hw-offload: on

    This patch reworks the bonding GSO offload support by:
    - making aggregating gso_partial_features across slaves similar to the
      other feature sets (this part is a no-op).
    - advertising the default partial gso features on empty bond devs, same
      as with other feature sets (also a no-op).
    - adding NETIF_F_GSO_PARTIAL to hw_enc_features filtered across slaves.
    - adding NETIF_F_GSO_PARTIAL to features in bond_setup()

    With all of these, 'ethtool -k bond0 | grep esp' now reports:
    tx-esp-segmentation: on
    esp-hw-offload: on
    esp-tx-csum-hw-offload: on

    Fixes: 4861333 ("bonding: add ESP offload features when slaves support")
    Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
    Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
    Acked-by: Jay Vosburgh <jv@jvosburgh.net>
    Link: https://patch.msgid.link/20250127104147.759658-1-cratiu@nvidia.com
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Signed-off-by: CKI Backport Bot <cki-ci-bot+cki-gitlab-backport-bot@redhat.com>

Author: CKI Backport Bot

drivers/net/bonding/bond_main.c

@@ -1539,17 +1539,20 @@ static netdev_features_t bond_fix_features(struct net_device *dev,
 				 NETIF_F_HIGHDMA | NETIF_F_LRO)
 
 #define BOND_ENC_FEATURES	(NETIF_F_HW_CSUM | NETIF_F_SG | \
-				 NETIF_F_RXCSUM | NETIF_F_GSO_SOFTWARE)
+				 NETIF_F_RXCSUM | NETIF_F_GSO_SOFTWARE | \
+				 NETIF_F_GSO_PARTIAL)
 
 #define BOND_MPLS_FEATURES	(NETIF_F_HW_CSUM | NETIF_F_SG | \
 				 NETIF_F_GSO_SOFTWARE)
 
+#define BOND_GSO_PARTIAL_FEATURES (NETIF_F_GSO_ESP)
+
 
 static void bond_compute_features(struct bonding *bond)
 {
+	netdev_features_t gso_partial_features = BOND_GSO_PARTIAL_FEATURES;
 	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
@@ -1583,8 +1586,9 @@ static void bond_compute_features(struct bonding *bond)
 							  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;
+		gso_partial_features = netdev_increment_features(gso_partial_features,
+								 slave->dev->gso_partial_features,
+								 BOND_GSO_PARTIAL_FEATURES);
 
 		mpls_features = netdev_increment_features(mpls_features,
 							  slave->dev->mpls_features,
@@ -1599,12 +1603,8 @@ static void bond_compute_features(struct bonding *bond)
 	}
 	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->gso_partial_features = gso_partial_features;
 	bond_dev->vlan_features = vlan_features;
 	bond_dev->hw_enc_features = enc_features | NETIF_F_GSO_ENCAP_ALL |
 				    NETIF_F_HW_VLAN_CTAG_TX |
@@ -6037,6 +6037,7 @@ void bond_setup(struct net_device *bond_dev)
 	bond_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL;
 	bond_dev->features |= bond_dev->hw_features;
 	bond_dev->features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX;
+	bond_dev->features |= NETIF_F_GSO_PARTIAL;
 #ifdef CONFIG_XFRM_OFFLOAD
 	bond_dev->hw_features |= BOND_XFRM_FEATURES;
 	/* Only enable XFRM features if this is an active-backup config */