On Wed, 2025-01-22 at 13:52 +0000, Hangbin Liu wrote:
The fixed commit adds NETIF_F_GSO_ESP bit for bonding gso_partial_features. However, if we don't set the dev NETIF_F_GSO_PARTIAL bit, the later netdev_change_features() -> netdev_fix_features() will remove the NETIF_F_GSO_ESP bit from the dev features. This causes ethtool to show that the bond does not support tx-esp-segmentation. For example
# ethtool -k bond0 | grep esp tx-esp-segmentation: off [requested on] esp-hw-offload: on esp-tx-csum-hw-offload: on
Add the NETIF_F_GSO_PARTIAL bit to bond dev features when set gso_partial_features to fix this issue.
Fixes: 4861333b4217 ("bonding: add ESP offload features when slaves support") Reported-by: Liang Li liali@redhat.com Signed-off-by: Hangbin Liu liuhangbin@gmail.com
v2: remove NETIF_F_GSO_PARTIAL bit if not set gso_partial_features.
I don't think this is needed, to avoid having bond_compute_features modify bond_dev->features directly. And in general, I think NETIF_F_GSO_PARTIAL should be set in bond_setup once and left on.
NETIF_F_GSO_PARTIAL is used in __skb_gso_segment to invoke skb_gso_ok, which checks if skb->gso_type is in (features & gso_partial_features). If not, it locally disables NETIF_F_GSO_PARTIAL. Later, skb_segment does another check for skb_gso_ok and skips segmentation if NETIF_F_GSO_PARTIAL is locally disabled. So a packet with SKB_GSO_ESP sent on a device with only NETIF_F_GSO_PARTIAL but no NETIF_F_GSO_ESP with behave correctly: __skb_gso_segment will locally remove NETIF_F_GSO_PARTIAL and skb_segment will not do segmentation.
The issue is reported internally, so there is no Closes tag.
BTW, I saw some drivers set NETIF_F_GSO_PARTIAL on dev->features. Some other drivers set NETIF_F_GSO_PARTIAL on dev->hw_enc_features. I haven't see a doc about where we should set. So I just set it on dev-
features.
It seems NETIF_F_GSO_PARTIAL is needed on both features and hw_enc_features, otherwise traffic is not segmented and performance suffers. netif_skb_features returns the intersection of features & hw_enc_features, and that is used to drive skb_gso_segment. The same approach (features & hw_enc_features) is taken in a few .gso_segment callbacks.
drivers/net/bonding/bond_main.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 7b78c2bada81..09d5a8433d86 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1598,10 +1598,13 @@ 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)
- if (gso_partial_features & NETIF_F_GSO_ESP) {
bond_dev->gso_partial_features |= NETIF_F_GSO_ESP;
- else
bond_dev->features |= NETIF_F_GSO_PARTIAL;- } else {
bond_dev->gso_partial_features &= ~NETIF_F_GSO_ESP;
bond_dev->features &= ~NETIF_F_GSO_PARTIAL;- }
done: bond_dev->vlan_features = vlan_features;