Re: [PATCH bpf-next v10 01/23] selftests/bpf: regroup and declare similar kfuncs selftests in an array

[Kumar Kartikeya Dwivedi]

On Fri, 2 Sept 2022 at 15:29, Benjamin Tissoires
<benjamin.tissoires@xxxxxxxxxx> wrote:
>
> Similar to tools/testing/selftests/bpf/prog_tests/dynptr.c:
> we declare an array of tests that we run one by one in a for loop.
>
> Followup patches will add more similar-ish tests, so avoid a lot of copy
> paste by grouping the declaration in an array.
>
> To be able to call bpf_object__find_program_by_name(), we need to use
> plain libbpf calls, and not light skeletons. So also change the Makefile
> to not generate light skeletons.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
>
> ---

I see your point, but this is also a test so that we keep verifying
kfunc call in light skeleton.
Code for relocating both is different in libbpf (we generate BPF ASM
for light skeleton so it is done inside a loader BPF program instead
of userspace).
You might then be able to make it work for both light and normal skeleton.

>
> new in v10
> ---
>  tools/testing/selftests/bpf/Makefile          |  2 +-
>  .../selftests/bpf/prog_tests/kfunc_call.c     | 56 +++++++++++++------
>  2 files changed, 39 insertions(+), 19 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index eecad99f1735..b19b0b35aec8 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -351,7 +351,7 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h               \
>                 test_subskeleton.skel.h test_subskeleton_lib.skel.h     \
>                 test_usdt.skel.h
>
> -LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \
> +LSKELS := fentry_test.c fexit_test.c fexit_sleep.c \
>         test_ringbuf.c atomics.c trace_printk.c trace_vprintk.c \
>         map_ptr_kern.c core_kern.c core_kern_overflow.c
>  # Generate both light skeleton and libbpf skeleton for these
> diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
> index eede7c304f86..21e347f46c93 100644
> --- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
> +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
> @@ -2,16 +2,28 @@
>  /* Copyright (c) 2021 Facebook */
>  #include <test_progs.h>
>  #include <network_helpers.h>
> -#include "kfunc_call_test.lskel.h"
> +#include "kfunc_call_test.skel.h"
>  #include "kfunc_call_test_subprog.skel.h"
>  #include "kfunc_call_test_subprog.lskel.h"
>  #include "kfunc_call_destructive.skel.h"
>
>  #include "cap_helpers.h"
>
> -static void test_main(void)
> +struct kfunc_test_params {
> +       const char *prog_name;
> +       int retval;
> +};
> +
> +static struct kfunc_test_params kfunc_tests[] = {
> +       {"kfunc_call_test1", 12},
> +       {"kfunc_call_test2", 3},
> +       {"kfunc_call_test_ref_btf_id", 0},
> +};
> +
> +static void verify_success(struct kfunc_test_params *param)
>  {
> -       struct kfunc_call_test_lskel *skel;
> +       struct kfunc_call_test *skel;
> +       struct bpf_program *prog;
>         int prog_fd, err;
>         LIBBPF_OPTS(bpf_test_run_opts, topts,
>                 .data_in = &pkt_v4,
> @@ -19,26 +31,35 @@ static void test_main(void)
>                 .repeat = 1,
>         );
>
> -       skel = kfunc_call_test_lskel__open_and_load();
> +       skel = kfunc_call_test__open_and_load();
>         if (!ASSERT_OK_PTR(skel, "skel"))
>                 return;
>
> -       prog_fd = skel->progs.kfunc_call_test1.prog_fd;
> -       err = bpf_prog_test_run_opts(prog_fd, &topts);
> -       ASSERT_OK(err, "bpf_prog_test_run(test1)");
> -       ASSERT_EQ(topts.retval, 12, "test1-retval");
> +       prog = bpf_object__find_program_by_name(skel->obj, param->prog_name);
> +       if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
> +               goto cleanup;
>
> -       prog_fd = skel->progs.kfunc_call_test2.prog_fd;
> +       prog_fd = bpf_program__fd(prog);
>         err = bpf_prog_test_run_opts(prog_fd, &topts);
> -       ASSERT_OK(err, "bpf_prog_test_run(test2)");
> -       ASSERT_EQ(topts.retval, 3, "test2-retval");
> +       if (!ASSERT_OK(err, param->prog_name))
> +               goto cleanup;
>
> -       prog_fd = skel->progs.kfunc_call_test_ref_btf_id.prog_fd;
> -       err = bpf_prog_test_run_opts(prog_fd, &topts);
> -       ASSERT_OK(err, "bpf_prog_test_run(test_ref_btf_id)");
> -       ASSERT_EQ(topts.retval, 0, "test_ref_btf_id-retval");
> +       ASSERT_EQ(topts.retval, param->retval, "retval");
> +
> +cleanup:
> +       kfunc_call_test__destroy(skel);
> +}
> +
> +static void test_main(void)
> +{
> +       int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(kfunc_tests); i++) {
> +               if (!test__start_subtest(kfunc_tests[i].prog_name))
> +                       continue;
>
> -       kfunc_call_test_lskel__destroy(skel);
> +               verify_success(&kfunc_tests[i]);
> +       }
>  }
>
>  static void test_subprog(void)
> @@ -121,8 +142,7 @@ static void test_destructive(void)
>
>  void test_kfunc_call(void)
>  {
> -       if (test__start_subtest("main"))
> -               test_main();
> +       test_main();
>
>         if (test__start_subtest("subprog"))
>                 test_subprog();
> --
> 2.36.1
>