Re: [PATCH bpf-next v3 2/3] libbpf: add low level TC-BPF API

On 4/22/21 11:47 AM, Shaun Crampton wrote:

quoted

Nope, just get it from the prog itself.

Looks like the API returns the prog ID, so from that we can look up the prog
and then get its tag? If so that meets our needs.  Alternatively, if
the API allows
for atomic replacement of a BPF program with another, that'd also work for us.

Both is the case: from prog ID you can already retrieve that same tag, and progs
can be atomically replaced with the current API code.

Exposing the tag in here otherwise feels just odd/wrong from a design PoV, explain
that to a user of this API on /why/ such field is in the tc API when it already
can be retrieved via bpf_prog_get_info_by_fd(), as in, what is so special on this
field in the tc API here (aside from legacy reasons when there was no mentioned
helper [which we don't need to support given it dates way too far back]) ... I
cannot. ;-) Hence lets drop it from there.

Thanks,
Daniel