Re: [PATCH v22 bpf-next 18/23] libbpf: Add SEC name for xdp multi-frags programs

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> On Mon, Jan 17, 2022 at 06:28:30PM +0100, Lorenzo Bianconi wrote:
> > Introduce support for the following SEC entries for XDP multi-frags
> > property:
> > - SEC("xdp.frags")
> > - SEC("xdp.frags/devmap")
> > - SEC("xdp.frags/cpumap")
> > 
> > Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
> > Acked-by: John Fastabend <john.fastabend@gmail.com>
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> >  tools/lib/bpf/libbpf.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index fdb3536afa7d..611e81357fb6 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -6562,6 +6562,9 @@ static int libbpf_preload_prog(struct bpf_program *prog,
> >  	if (def & SEC_SLEEPABLE)
> >  		opts->prog_flags |= BPF_F_SLEEPABLE;
> >  
> > +	if (prog->type == BPF_PROG_TYPE_XDP && strstr(prog->sec_name, ".frags"))
> > +		opts->prog_flags |= BPF_F_XDP_HAS_FRAGS;
> 
> That's a bit sloppy.
> Could you handle it similar to SEC_SLEEPABLE?
> 
> > +
> >  	if ((prog->type == BPF_PROG_TYPE_TRACING ||
> >  	     prog->type == BPF_PROG_TYPE_LSM ||
> >  	     prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
> > @@ -8600,8 +8603,11 @@ static const struct bpf_sec_def section_defs[] = {
> >  	SEC_DEF("lsm.s/",		LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm),
> >  	SEC_DEF("iter/",		TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF, attach_iter),
> >  	SEC_DEF("syscall",		SYSCALL, 0, SEC_SLEEPABLE),
> > +	SEC_DEF("xdp.frags/devmap",	XDP, BPF_XDP_DEVMAP, SEC_NONE),
> >  	SEC_DEF("xdp_devmap/",		XDP, BPF_XDP_DEVMAP, SEC_ATTACHABLE),
> > +	SEC_DEF("xdp.frags/cpumap",	XDP, BPF_XDP_CPUMAP, SEC_NONE),
> >  	SEC_DEF("xdp_cpumap/",		XDP, BPF_XDP_CPUMAP, SEC_ATTACHABLE),
> > +	SEC_DEF("xdp.frags",		XDP, BPF_XDP, SEC_NONE),
> 
> It would be SEC_FRAGS here instead of SEC_NONE.

ack, I dropped SEC_FRAGS (SEC_XDP_MB before) from sec_def_flags because Andrii asked to remove
it but I am fine to add it back. Agree?

Regards,
Lorenzo

> 
> >  	SEC_DEF("xdp",			XDP, BPF_XDP, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX),
> >  	SEC_DEF("perf_event",		PERF_EVENT, 0, SEC_NONE | SEC_SLOPPY_PFX),
> >  	SEC_DEF("lwt_in",		LWT_IN, 0, SEC_NONE | SEC_SLOPPY_PFX),
> > -- 
> > 2.34.1
> > 
> 
> -- 

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