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From:   Andrii Nakryiko <andrii.nakryiko@gmail.com>
Date:   Fri, 8 Jan 2021 12:25:22 -0800
Message-ID: <CAEf4BzZr=hgWGuU4EPEZbavAsN7hy+j-9RQAL7xvfMJ8hqv58g@mail.gmail.com>
Subject: Re: [PATCH] tools/bpf: Remove unnecessary parameter in bpf_object__probe_loading
To:     =?UTF-8?B?5b2t5rWpKFJpY2hhcmQp?= <richard.peng@oppo.com>
Cc:     "ast@kernel.org" <ast@kernel.org>,
        "andrii@kernel.org" <andrii@kernel.org>,
        "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Thu, Jan 7, 2021 at 6:08 PM =E5=BD=AD=E6=B5=A9(Richard) <richard.peng@op=
po.com> wrote:
>
> struct bpf_object *obj is not used in bpf_object__probe_loading, so we
> can remove it.
>
> Signed-off-by: Peng Hao <richard.peng@oppo.com>
> ---

It causes no harm, no performance cost, and no maintenance issues. I
consider eventually allowing to have a per-bpf_object log callback (as
opposed to current global one), so at that time I'd need to re-add
struct bpf_object back to this. Which means just unnecessary code
churn.

So thanks for the patch, there is nothing wrong with it, but I'll
leave this code as is for now. Thanks!


>  tools/lib/bpf/libbpf.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 313034117070..17d90779f09a 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -3685,7 +3685,7 @@ int bpf_map__resize(struct bpf_map *map, __u32 max_=
entries)
>  }
>
>  static int
> -bpf_object__probe_loading(struct bpf_object *obj)
> +bpf_object__probe_loading(void)
>  {
>         struct bpf_load_program_attr attr;
>         char *cp, errmsg[STRERR_BUFSIZE];
> @@ -7258,7 +7258,7 @@ int bpf_object__load_xattr(struct bpf_object_load_a=
ttr *attr)
>                 return -EINVAL;
>         }
>
> -       err =3D bpf_object__probe_loading(obj);
> +       err =3D bpf_object__probe_loading();
>         err =3D err ? : bpf_object__load_vmlinux_btf(obj);
>         err =3D err ? : bpf_object__resolve_externs(obj, obj->kconfig);
>         err =3D err ? : bpf_object__sanitize_and_load_btf(obj);
> --
> 2.18.4