Re: [PATCH net] veth: Update XDP feature set when bringing up device

Paolo Abeni [off-list ref] writes:

Hi,

On Mon, 2023-09-11 at 15:58 +0200, Toke Høiland-Jørgensen wrote:

quoted

There's an early return in veth_set_features() if the device is in a down
state, which leads to the XDP feature flags not being updated when enabling
GRO while the device is down. Which in turn leads to XDP_REDIRECT not
working, because the redirect code now checks the flags.

Fix this by updating the feature flags after bringing the device up.

Before this patch:

NETDEV_XDP_ACT_BASIC:		yes
NETDEV_XDP_ACT_REDIRECT:	yes
NETDEV_XDP_ACT_NDO_XMIT:	no
NETDEV_XDP_ACT_XSK_ZEROCOPY:	no
NETDEV_XDP_ACT_HW_OFFLOAD:	no
NETDEV_XDP_ACT_RX_SG:		yes
NETDEV_XDP_ACT_NDO_XMIT_SG:	no

After this patch:

NETDEV_XDP_ACT_BASIC:		yes
NETDEV_XDP_ACT_REDIRECT:	yes
NETDEV_XDP_ACT_NDO_XMIT:	yes
NETDEV_XDP_ACT_XSK_ZEROCOPY:	no
NETDEV_XDP_ACT_HW_OFFLOAD:	no
NETDEV_XDP_ACT_RX_SG:		yes
NETDEV_XDP_ACT_NDO_XMIT_SG:	yes

Fixes: fccca038f300 ("veth: take into account device reconfiguration for xdp_features flag")
Fixes: 66c0e13ad236 ("drivers: net: turn on XDP features")
Signed-off-by: Toke Høiland-Jørgensen <redacted>
---
 drivers/net/veth.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 9c6f4f83f22b..0deefd1573cf 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c

@@ -1446,6 +1446,8 @@ static int veth_open(struct net_device *dev)
 		netif_carrier_on(peer);
 	}
 
+	veth_set_xdp_features(dev);
+
 	return 0;
 }

The patch LGTM, thanks!

I think it would be nice to add some specific self-tests here. Could
you please consider following-up with them?

Sure! Do you want me to resubmit this as well, or are you just going to
apply it as-is and do the selftest as a follow-up?

-Toke