On Fri, May 20, 2022 at 1:51 PM Martin KaFai Lau <kafai@xxxxxx> wrote:
>
> On Tue, May 10, 2022 at 01:59:19PM -0700, Kui-Feng Lee wrote:
> [ ... ]
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -1013,6 +1013,7 @@ enum bpf_link_type {
> > BPF_LINK_TYPE_XDP = 6,
> > BPF_LINK_TYPE_PERF_EVENT = 7,
> > BPF_LINK_TYPE_KPROBE_MULTI = 8,
> > + BPF_LINK_TYPE_STRUCT_OPS = 9,
> Sorry for the late question. I just noticed it while looking at the
> cgroup-lsm set.
>
> Does BPF_LINK_TYPE_STRUCT_OPS need to be in the uapi?
> The current links of the struct_ops progs should not be
> visible to the user space.
>
bpf_link_init() expects link_type to be specified, so we have to
provide some value. We probably could have specified
BPF_LINK_TYPE_UNSPEC, but that seems wrong. But right now those links
are not going to be visible outside as they don't get their ID
allocated (no bpf_link_settle() call), so we just basically have a
reserved enum for future STRUCT_OPS link, if we ever add it
explicitly.
> >
> > MAX_BPF_LINK_TYPE,
> > };
[...]
