> 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). > > I'm not arguing against removing this check in the future, I'm just wondering > if we need a different mechanism than outright prohibiting XDP_REDIRECT with MB > to protect against the redirected device not having MB support? > > > > > > ri->map_id = 0; /* Valid map id idr range: [1,INT_MAX[ */ > > > ri->map_type = BPF_MAP_TYPE_UNSPEC; > > > > > > > > >
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