From: Ignat Korchagin ignat@cloudflare.com
[ Upstream commit d7db7775ea2e31502d46427f5efd385afc4ff1eb ]
Commit d3256efd8e8b ("veth: allow enabling NAPI even without XDP") tried to fix the fact that GRO was not possible without XDP, because veth did not use NAPI without XDP. However, it also introduced the behaviour that GRO is always enabled, when XDP is enabled.
While it might be desired for most cases, it is confusing for the user at best as the GRO flag suddenly changes, when an XDP program is attached. It also introduces some complexities in state management as was partially addressed in commit fe9f801355f0 ("net: veth: clear GRO when clearing XDP even when down").
But the biggest problem is that it is not possible to disable GRO at all, when an XDP program is attached, which might be needed for some use cases.
Fix this by not touching the GRO flag on XDP enable/disable as the code already supports switching to NAPI if either GRO or XDP is requested.
Link: https://lore.kernel.org/lkml/20240311124015.38106-1-ignat@cloudflare.com/ Fixes: d3256efd8e8b ("veth: allow enabling NAPI even without XDP") Fixes: fe9f801355f0 ("net: veth: clear GRO when clearing XDP even when down") Signed-off-by: Ignat Korchagin ignat@cloudflare.com Reviewed-by: Toke Høiland-Jørgensen toke@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/veth.c | 18 ------------------ 1 file changed, 18 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c index a2e80278eb2f9..2f3fd287378fd 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -1533,8 +1533,6 @@ static netdev_features_t veth_fix_features(struct net_device *dev, if (peer_priv->_xdp_prog) features &= ~NETIF_F_GSO_SOFTWARE; } - if (priv->_xdp_prog) - features |= NETIF_F_GRO;
return features; } @@ -1638,14 +1636,6 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog, }
if (!old_prog) { - if (!veth_gro_requested(dev)) { - /* user-space did not require GRO, but adding - * XDP is supposed to get GRO working - */ - dev->features |= NETIF_F_GRO; - netdev_features_change(dev); - } - peer->hw_features &= ~NETIF_F_GSO_SOFTWARE; peer->max_mtu = max_mtu; } @@ -1661,14 +1651,6 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog, if (dev->flags & IFF_UP) veth_disable_xdp(dev);
- /* if user-space did not require GRO, since adding XDP - * enabled it, clear it now - */ - if (!veth_gro_requested(dev)) { - dev->features &= ~NETIF_F_GRO; - netdev_features_change(dev); - } - if (peer) { peer->hw_features |= NETIF_F_GSO_SOFTWARE; peer->max_mtu = ETH_MAX_MTU;