Re: [PATCH bpf-next v3 7/8] libbpf: add bpf_map__inner_map API

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

On Wed, Mar 31, 2021 at 9:45 AM Yauheni Kaliuta
<yauheni.kaliuta@redhat.com> wrote:
>
> From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
>
> The API gives access to inner map for map in map types (array or
> hash of map). It will be used to dynamically set max_entries in it.
>
> Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
> ---
>  tools/lib/bpf/libbpf.c   | 10 ++++++++++
>  tools/lib/bpf/libbpf.h   |  1 +
>  tools/lib/bpf/libbpf.map |  1 +
>  3 files changed, 12 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 7aad78dbb4b4..b48dc380059d 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -2194,6 +2194,7 @@ static int parse_btf_map_def(struct bpf_object *obj,
>                         map->inner_map = calloc(1, sizeof(*map->inner_map));
>                         if (!map->inner_map)
>                                 return -ENOMEM;
> +                       map->inner_map->fd = -1;
>                         map->inner_map->sec_idx = obj->efile.btf_maps_shndx;
>                         map->inner_map->name = malloc(strlen(map->name) +
>                                                       sizeof(".inner") + 1);
> @@ -3845,6 +3846,14 @@ __u32 bpf_map__max_entries(const struct bpf_map *map)
>         return map->def.max_entries;
>  }
>
> +struct bpf_map *bpf_map__inner_map(struct bpf_map *map)
> +{
> +    if (!bpf_map_type__is_map_in_map(map->def.type))
> +        return NULL;
> +
> +    return map->inner_map;
> +}
> +
>  int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries)
>  {
>         if (map->fd >= 0)
> @@ -9476,6 +9485,7 @@ int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
>                 pr_warn("error: inner_map_fd already specified\n");
>                 return -EINVAL;
>         }
> +       zfree(&map->inner_map);
>         map->inner_map_fd = fd;
>         return 0;
>  }
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index f500621d28e5..bec4e6a6e31d 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -480,6 +480,7 @@ LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path);
>  LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path);
>
>  LIBBPF_API int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd);
> +LIBBPF_API struct bpf_map *bpf_map__inner_map(struct bpf_map *map);
>
>  LIBBPF_API long libbpf_get_error(const void *ptr);
>
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index f5990f7208ce..eeb6d5ebd1cc 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -360,4 +360,5 @@ LIBBPF_0.4.0 {
>                 bpf_linker__free;
>                 bpf_linker__new;
>                 bpf_object__set_kversion;
> +               bpf_map__inner_map;

please keep the list sorted alphabetically

>  } LIBBPF_0.3.0;
> --
> 2.31.1
>