On 2019/5/20 下午5:11, Jiri Pirko wrote:
Sun, May 19, 2019 at 05:10:46AM CEST, stephen@xxxxxxxxxxxxxxxxxx wrote:When a device is stacked like (team, bonding, failsafe or netvsc) the XDP generic program for the parent device is not called. In these cases, the rx handler changes skb->dev to its own in the receive handler, and returns RX_HANDLER_ANOTHER. Fix this by calling do_xdp_generic if necessary before starting another round. Review of all the places RX_HANDLER_ANOTHER is returned show that the current devices do correctly change skb->dev. There was an older patch that got abandoned that did the same thing, this is just a rewrite. Suggested-by: Jason Wang <jasowang@xxxxxxxxxx> Fixes: d445516966dc ("net: xdp: support xdp generic on virtual devices") Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx> Acked-by: Jason Wang <jasowang@xxxxxxxxxx> --- net/core/dev.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index b6b8505cfb3e..240d0b2de1a8 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4921,6 +4921,16 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc, ret = NET_RX_SUCCESS; goto out; case RX_HANDLER_ANOTHER: + if (static_branch_unlikely(&generic_xdp_needed_key)) { + struct bpf_prog *xdp_prog; + + xdp_prog = rcu_dereference(skb->dev->xdp_prog); + ret = do_xdp_generic(xdp_prog, skb); + if (ret != XDP_PASS) { + ret = NET_RX_SUCCESS; + goto out; + } + }I'm always scarred of changes like this. The history tells us that this codepaths are very fragile. It took us non-trivial efford to fix bonding here, not to mention vlans (that was pain).
I may miss something, did you see any issue for bonding with this patch?
The reason for troubles was often fact that different flows were treated differently (vlan accel/non-accel).
Do you mean we need do something similar after vlan_do_receive() returns true?
This patch calls do_xdp_generic for master device in different point in the receive patch comparing to lower device. Would it be possible to unify this? E.g. by moving do_xdp_generice() call from netif_rx_internal()/netif_receive_skb_internal() here, to the beginning of __netif_receive_skb_core()?
Probably just after another_round label. And this means generic XDP is done after RPS which could be even better.
Thanks
goto another_round; case RX_HANDLER_EXACT: deliver_exact = true; -- 2.20.1
