Re: [PATCH v2 bpf-next 1/4] libbpf: migrate internal use of bpf_program__get_prog_info_linear

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Mon, Oct 11, 2021 at 1:20 AM Dave Marchevsky <davemarchevsky@fb.com> wrote:
>
> In preparation for bpf_program__get_prog_info_linear, move the single

for bpf_program__get_prog_info_linear *deprecation* ? fixed it up while applying

> use in libbpf to call bpf_obj_get_info_by_fd directly.
>
> Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
> ---

I've applied this patch for now, as it is pretty independent (and I've
already fixed it up already and didn't want to lose that :) I hope you
don't mind.

>  tools/lib/bpf/libbpf.c | 15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index ed313fd491bd..8b86c4831aa8 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -8459,26 +8459,24 @@ int libbpf_find_vmlinux_btf_id(const char *name,
>
>  static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
>  {
> -       struct bpf_prog_info_linear *info_linear;
> -       struct bpf_prog_info *info;
> +       struct bpf_prog_info info = {};
> +       __u32 info_len = sizeof(info);
>         struct btf *btf;
>         int err;
>
> -       info_linear = bpf_program__get_prog_info_linear(attach_prog_fd, 0);
> -       err = libbpf_get_error(info_linear);
> +       err = bpf_obj_get_info_by_fd(attach_prog_fd, &info, &info_len);
>         if (err) {
> -               pr_warn("failed get_prog_info_linear for FD %d\n",
> +               pr_warn("failed bpf_obj_get_info_by_fd for FD %d\n",

I've also added err code into warn message here

>                         attach_prog_fd);
>                 return err;
>         }
>
>         err = -EINVAL;
> -       info = &info_linear->info;
> -       if (!info->btf_id) {
> +       if (!info.btf_id) {
>                 pr_warn("The target program doesn't have BTF\n");
>                 goto out;
>         }
> -       btf = btf__load_from_kernel_by_id(info->btf_id);
> +       btf = btf__load_from_kernel_by_id(info.btf_id);
>         if (libbpf_get_error(btf)) {
>                 pr_warn("Failed to get BTF of the program\n");

and here




>                 goto out;
> @@ -8490,7 +8488,6 @@ static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
>                 goto out;
>         }
>  out:
> -       free(info_linear);
>         return err;
>  }
>
> --
> 2.30.2
>