On Tue, 13 Jun 2017 17:37:50 -0700, Martin KaFai Lau wrote:
> On Tue, Jun 13, 2017 at 04:52:32PM -0700, Jakub Kicinski wrote:
> > On Tue, 13 Jun 2017 14:08:40 -0700, Martin KaFai Lau wrote:
> > > - case XDP_QUERY_PROG:
> > > - xdp->prog_attached = !!nn->dp.xdp_prog;
> > > + case XDP_QUERY_PROG: {
> > > + const struct bpf_prog *xdp_prog;
> > > +
> > > + xdp_prog = nn->dp.xdp_prog;
> > > + if (xdp_prog) {
> > > + xdp->prog_id = xdp_prog->aux->id;
> > > + xdp->prog_attached = true;
> > > + } else {
> > > + xdp->prog_id = 0;
> > > + xdp->prog_attached = false;
> > > + }
> > > return 0;
> > > + }
> >
> > I'm sorry to nit pick but it could be done on a single line:
> >
> > case XDP_QUERY_PROG:
> > xdp->prog_attached = !!nn->dp.xdp_prog;
> > + xdp->prog_id = nn->dp.xdp_prog ? nn->dp.xdp_prog->aux->id : 0;
> > return 0;
> > default:
> > return -EINVAL;
> OK...
>
> >
> >
> > What would be even cooler is a helper like this:
> >
> > static inline u32 bpf_prog_id(struct bpf_prog *prog)
> > {
> > if (!prog)
> > return 0;
> > return prog->aux->id;
> > }
> >
> > in linux/bpf.h.
> Good idea.
You may actually have to add that into a source file, because bpf.h
does not know the definition of struct bpf_prog :(
> I had been thinking I may not need to change all the
> drivers now. I did that in v1 because I wanted to remove
> prog_attached which is redundant. With prog_attached reserved,
> prog_id is optional.
>
> Considering I don't have all the hardwares to test it, I think
> it may make more sense for me to only change the HW that I have?
Coccinelle to the rescue?
@@
expression ex;
@@
xdp->prog_attached = !!(ex);
+ xdp->prog_id = bpf_prog_id(ex);
> > In patch 1 I would be tempted to add a new command for getting the prog
> > id, instead of muxing through query to avoid the output parameter? But
> > I'm OK with the code as is, its just a preference rather than an objection
> > :)
> Have one command to query a new field? I think it is overkilled.
Perhaps. I was just trying to come up with a way of avoiding the
output parameter. It seems hard to do unless we stop using
__dev_xdp_attached() for filling in the netlink attributes. I'm OK
with leaving the code as is..
