Re: [PATCH net-next 08/10] bpf: nfp: Report bpf_prog ID during XDP_QUERY_PROG

[Martin KaFai Lau]

On Mon, Jun 12, 2017 at 06:28:42PM -0700, Jakub Kicinski wrote:
> On Mon, 12 Jun 2017 18:00:23 -0700, Martin KaFai Lau wrote:
> > +   case XDP_QUERY_PROG: {
> > +           const struct bpf_prog *xdp_prog;
> > +
> > +           xdp_prog = READ_ONCE(nn->dp.xdp_prog);
> > +           if (xdp_prog)
> > +                   xdp->prog_id = xdp_prog->aux->id;
> > +           else
> > +                   xdp->prog_id = 0;
> >             return 0;
> > +   }
> >     default:
> >             return -EINVAL;
> >     }
>
> Why READ_ONCE?  I thought .ndo_xdp is always called under RTNL.
will remove in the next spin.