Re: [PATCHv2 bpf-next] selftests/bpf: Add missing bpf_iter_vma_offset__destroy call

[Jiri Olsa <olsajiri@gmail.com>]

On Thu, Oct 06, 2022 at 10:36:08AM -0700, Andrii Nakryiko wrote:
> On Thu, Oct 6, 2022 at 10:21 AM Martin KaFai Lau <martin.lau@linux.dev> wrote:
> >
> > On 10/6/22 1:31 AM, Jiri Olsa wrote:
> > > Adding missing bpf_iter_vma_offset__destroy call and using in-skeletin
> > > link pointer so we don't need extra bpf_link__destroy call.
> > >
> > > Fixes: b3e1331eb925 ("selftests/bpf: Test parameterized task BPF iterators.")
> > > Cc: Kui-Feng Lee <kuifeng@fb.com>
> > > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > > ---
> > >   v2 changes:
> > >   - use in-skeletin link pointer and destroy call [Martin]
> > >
> > >   tools/testing/selftests/bpf/prog_tests/bpf_iter.c | 13 +++++++------
> > >   1 file changed, 7 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> > > index 3369c5ec3a17..d4437a2bba28 100644
> > > --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> > > +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> > > @@ -1498,7 +1498,6 @@ static noinline int trigger_func(int arg)
> > >   static void test_task_vma_offset_common(struct bpf_iter_attach_opts *opts, bool one_proc)
> > >   {
> > >       struct bpf_iter_vma_offset *skel;
> > > -     struct bpf_link *link;
> > >       char buf[16] = {};
> > >       int iter_fd, len;
> > >       int pgsz, shift;
> > > @@ -1513,11 +1512,13 @@ static void test_task_vma_offset_common(struct bpf_iter_attach_opts *opts, bool
> > >               ;
> > >       skel->bss->page_shift = shift;
> > >
> > > -     link = bpf_program__attach_iter(skel->progs.get_vma_offset, opts);
> > > -     if (!ASSERT_OK_PTR(link, "attach_iter"))
> > > -             return;
> > > +     skel->links.get_vma_offset = bpf_program__attach_iter(skel->progs.get_vma_offset, opts);
> > > +     if (!ASSERT_OK_PTR(skel->links.get_vma_offset, "attach_iter")) {
> > > +             skel->links.get_vma_offset = NULL;
> >
> > Applied with this NULL assignment removed.  bpf_link__destroy() can handle err
> > ptr.  Thanks.
> >
> 
> It's even better, with libbpf 1.0 there is no err ptr, it's NULL on
> error. So good call for removing this!

great, thanks :)

jirka

> 
> >
> > > +             goto exit;
> > > +     }
> > >
> > > -     iter_fd = bpf_iter_create(bpf_link__fd(link));
> > > +     iter_fd = bpf_iter_create(bpf_link__fd(skel->links.get_vma_offset));
> > >       if (!ASSERT_GT(iter_fd, 0, "create_iter"))
> > >               goto exit;
> > >
> > > @@ -1535,7 +1536,7 @@ static void test_task_vma_offset_common(struct bpf_iter_attach_opts *opts, bool
> > >       close(iter_fd);
> > >
> > >   exit:
> > > -     bpf_link__destroy(link);
> > > +     bpf_iter_vma_offset__destroy(skel);
> > >   }
> > >
> > >   static void test_task_vma_offset(void)
> >