On Mon, Apr 27, 2020 at 11:41:39PM -0700, Andrii Nakryiko wrote:
> diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
> index 60aad054eea1..e3a6e9a1f5b4 100644
> --- a/tools/lib/bpf/bpf_helpers.h
> +++ b/tools/lib/bpf/bpf_helpers.h
> @@ -12,6 +12,7 @@
>
> #define __uint(name, val) int (*name)[val]
> #define __type(name, val) typeof(val) *name
> +#define __inner(name, val) typeof(val) *name[]
...
> +++ b/tools/testing/selftests/bpf/progs/test_btf_map_in_map.c
> @@ -0,0 +1,76 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright (c) 2020 Facebook */
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +
> +struct inner_map {
> + __uint(type, BPF_MAP_TYPE_ARRAY);
> + __uint(max_entries, 1);
> + __type(key, int);
> + __type(value, int);
> +} inner_map1 SEC(".maps"),
> + inner_map2 SEC(".maps");
> +
> +struct outer_arr {
> + __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
> + __uint(max_entries, 3);
> + __uint(key_size, sizeof(int));
> + __uint(value_size, sizeof(int));
> + /* it's possible to use anonymous struct as inner map definition here */
> + __inner(values, struct {
> + __uint(type, BPF_MAP_TYPE_ARRAY);
> + /* changing max_entries to 2 will fail during load
> + * due to incompatibility with inner_map definition */
> + __uint(max_entries, 1);
> + __type(key, int);
> + __type(value, int);
> + });
How about renaming it s/__inner/__array/ ?
Because that's what it defines from BTF pov.
