Re: [PATCH v2] selftests/bpf: fix array_size.cocci warning

[Guo Zhengkui]

On 2022/3/12 2:38, Andrii Nakryiko wrote:
> On Tue, Mar 8, 2022 at 7:36 PM Guo Zhengkui <guozhengkui@xxxxxxxx> wrote:
> > Fix the array_size.cocci warning in tools/testing/selftests/bpf/
> >
> > Use `ARRAY_SIZE(arr)` in bpf_util.h instead of forms like
> > `sizeof(arr)/sizeof(arr[0])`.
> >
> > Signed-off-by: Guo Zhengkui <guozhengkui@xxxxxxxx>
> > ---
> >   .../selftests/bpf/prog_tests/cgroup_attach_autodetach.c     | 2 +-
> >   .../testing/selftests/bpf/prog_tests/cgroup_attach_multi.c  | 2 +-
> >   .../selftests/bpf/prog_tests/cgroup_attach_override.c       | 2 +-
> >   tools/testing/selftests/bpf/prog_tests/global_data.c        | 6 +++---
> >   tools/testing/selftests/bpf/prog_tests/obj_name.c           | 2 +-
> >   tools/testing/selftests/bpf/progs/syscall.c                 | 3 ++-
> >   tools/testing/selftests/bpf/progs/test_rdonly_maps.c        | 3 ++-
> >   tools/testing/selftests/bpf/test_cgroup_storage.c           | 2 +-
> >   tools/testing/selftests/bpf/test_lru_map.c                  | 4 ++--
> >   tools/testing/selftests/bpf/test_sock_addr.c                | 6 +++---
> >   tools/testing/selftests/bpf/test_sockmap.c                  | 4 ++--
> >   11 files changed, 19 insertions(+), 17 deletions(-)
>
> [...]
>
> > diff --git a/tools/testing/selftests/bpf/progs/test_rdonly_maps.c b/tools/testing/selftests/bpf/progs/test_rdonly_maps.c
> > index fc8e8a34a3db..a500f2c15970 100644
> > --- a/tools/testing/selftests/bpf/progs/test_rdonly_maps.c
> > +++ b/tools/testing/selftests/bpf/progs/test_rdonly_maps.c
> > @@ -3,6 +3,7 @@
> >
> >   #include <linux/ptrace.h>
> >   #include <linux/bpf.h>
> > +#include <bpf_util.h>
>
> bpf_util.h isn't supposed to be included from BPF source code side. Is
> this ARRAY_SIZE() use so important for BPF programs? Maybe just leave
> existing code under progs/*.c as is?

I think so. Just leave progs/*.c unchanged. I'll commit PATCH v3.

> >   #include <bpf/bpf_helpers.h>
> >
> >   const struct {
> > @@ -64,7 +65,7 @@ int full_loop(struct pt_regs *ctx)
> >   {
> >          /* prevent compiler to optimize everything out */
> >          unsigned * volatile p = (void *)&rdonly_values.a;
> > -       int i = sizeof(rdonly_values.a) / sizeof(rdonly_values.a[0]);
> > +       int i = ARRAY_SIZE(rdonly_values.a);
> >          unsigned iters = 0, sum = 0;
> >
> >          /* validate verifier can allow full loop as well */
>
> [...]

Zhengkui