Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx> writes: >> On Mon, Dec 6, 2021 at 11:11 AM Jesper Dangaard Brouer >> <jbrouer@xxxxxxxxxx> wrote: >> > >> > On 30/11/2021 12.53, Lorenzo Bianconi wrote: >> > > XDP_REDIRECT is not fully supported yet for xdp multi-buff since not >> > > all XDP capable drivers can map non-linear xdp_frame in ndo_xdp_xmit >> > > so disable it for the moment. >> > > >> > > Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx> >> > > --- >> > > net/core/filter.c | 7 +++++++ >> > > 1 file changed, 7 insertions(+) >> > > >> > > diff --git a/net/core/filter.c b/net/core/filter.c >> > > index b70725313442..a87d835d1122 100644 >> > > --- a/net/core/filter.c >> > > +++ b/net/core/filter.c >> > > @@ -4189,6 +4189,13 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, >> > > struct bpf_map *map; >> > > int err; >> > > >> > > + /* XDP_REDIRECT is not fully supported yet for xdp multi-buff since >> > > + * not all XDP capable drivers can map non-linear xdp_frame in >> > > + * ndo_xdp_xmit. >> > > + */ >> > > + if (unlikely(xdp_buff_is_mb(xdp))) >> > > + return -EOPNOTSUPP; >> > > + >> > >> > This approach also exclude 'cpumap' use-case, which you AFAIK have added >> > MB support for in this patchset. >> > >> > Generally this check is hopefully something we can remove again, once >> > drivers add MB ndo_xdp_xmit support. >> > >> >> What happens in the future when a new driver is added without (in its intial >> version) MB ndo_xdp_xmit support? Is MB support for ndo_xdp_xmit going to be a >> requirement for a driver (with ndo_xdp_xmit) to be accepted to the kernel? > > I think the optimal solution would be export the driver XDP capabilities (AFAIK > there is an ogoing effort for this, but it is not available yet). Until that materialises I think we can at least require new drivers to check the MB flag and drop the frame if it doesn't know what to do with it. A follow-on patch could also just update all the existing drivers to do this and then remove this check... -Toke
