Re: [PATCH v2 0/3] Assume libbpf 1.0+

[Ian Rogers]

On Sun, Jan 15, 2023 at 5:01 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> libbpf 1.0 was a major change in API. Perf has partially supported
> older libbpf's but an implementation may be:
> ..
>        pr_err("%s: not support, update libbpf\n", __func__);
>        return -ENOTSUP;
> ..
>
> Rather than build a binary that would fail at runtime it is
> preferrential just to build libbpf statically and link against
> that. The static version is in the kernel tools tree and newer than
> 1.0.
>
> These patches change the libbpf test to only pass when at least
> version 1.0 is installed, then remove the conditional build and
> feature logic.
>
> The issue is discussed here:
> https://lore.kernel.org/lkml/20230106151320.619514-1-irogers@xxxxxxxxxx/
> perf bpf:
>
> A variant of this fix was added to Linux 6.2 in:
> "perf bpf: Avoid build breakage with libbpf < 0.8.0 + LIBBPF_DYNAMIC=1"
> https://lore.kernel.org/lkml/Y71+eh00Ju7WeEFX@xxxxxxxxxx/
> This change goes further in removing logic that is now no longer
> necessary.
>
> v2. Rebase now that breakage fix patch is in linus/master.

I missed the:
Acked/Tested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
I believe we are waiting for package maintainer input.

Thanks,
Ian



> Ian Rogers (3):
>   tools build: Pass libbpf feature only if libbpf 1.0+
>   perf build: Remove libbpf pre-1.0 feature tests
>   perf bpf: Remove pre libbpf 1.0 conditional logic
>
>  tools/build/feature/Makefile                  |  7 --
>  .../feature/test-libbpf-bpf_map_create.c      |  8 ---
>  .../test-libbpf-bpf_object__next_map.c        |  8 ---
>  .../test-libbpf-bpf_object__next_program.c    |  8 ---
>  .../build/feature/test-libbpf-bpf_prog_load.c |  9 ---
>  .../test-libbpf-bpf_program__set_insns.c      |  8 ---
>  .../test-libbpf-btf__load_from_kernel_by_id.c |  8 ---
>  .../build/feature/test-libbpf-btf__raw_data.c |  8 ---
>  tools/build/feature/test-libbpf.c             |  4 ++
>  tools/perf/Makefile.config                    | 39 +----------
>  tools/perf/util/bpf-event.c                   | 66 -------------------
>  tools/perf/util/bpf-loader.c                  | 18 -----
>  tools/perf/util/bpf_counter.c                 | 18 -----
>  13 files changed, 5 insertions(+), 204 deletions(-)
>  delete mode 100644 tools/build/feature/test-libbpf-bpf_map_create.c
>  delete mode 100644 tools/build/feature/test-libbpf-bpf_object__next_map.c
>  delete mode 100644 tools/build/feature/test-libbpf-bpf_object__next_program.c
>  delete mode 100644 tools/build/feature/test-libbpf-bpf_prog_load.c
>  delete mode 100644 tools/build/feature/test-libbpf-bpf_program__set_insns.c
>  delete mode 100644 tools/build/feature/test-libbpf-btf__load_from_kernel_by_id.c
>  delete mode 100644 tools/build/feature/test-libbpf-btf__raw_data.c
>
> --
> 2.39.0.314.g84b9a713c41-goog
>