Re: [PATCH bpf-next 2/2] bpf: adding tests for mapinmap helpber in libbpf

[Y Song <ys114321@gmail.com>]

On Mon, Nov 19, 2018 at 4:13 PM Nikita V. Shirokov <tehnerd@tehnerd.com> wrote:
>
> adding test/example of bpf_map__add_inner_map_fd usage
>
> Signed-off-by: Nikita V. Shirokov <tehnerd@tehnerd.com>
> ---
>  tools/testing/selftests/bpf/Makefile        |  3 +-
>  tools/testing/selftests/bpf/test_mapinmap.c | 53 ++++++++++++++++++++
>  tools/testing/selftests/bpf/test_maps.c     | 76 +++++++++++++++++++++++++++++
>  3 files changed, 131 insertions(+), 1 deletion(-)
>  create mode 100644 tools/testing/selftests/bpf/test_mapinmap.c
>
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index 57b4712a6276..a3ea69dc9bdf 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -38,7 +38,8 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
>         test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o \
>         get_cgroup_id_kern.o socket_cookie_prog.o test_select_reuseport_kern.o \
>         test_skb_cgroup_id_kern.o bpf_flow.o netcnt_prog.o \
> -       test_sk_lookup_kern.o test_xdp_vlan.o test_queue_map.o test_stack_map.o
> +       test_sk_lookup_kern.o test_xdp_vlan.o test_queue_map.o test_stack_map.o \
> +       test_mapinmap.o
>
>  # Order correspond to 'make run_tests' order
>  TEST_PROGS := test_kmod.sh \
> diff --git a/tools/testing/selftests/bpf/test_mapinmap.c b/tools/testing/selftests/bpf/test_mapinmap.c
> new file mode 100644
> index 000000000000..8aef6c652c9c
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/test_mapinmap.c
> @@ -0,0 +1,53 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2018 Facebook */
> +#include <stddef.h>
> +#include <linux/bpf.h>
> +#include <linux/types.h>
> +#include "bpf_helpers.h"
> +
> +
nit: extra new line

> +struct bpf_map_def SEC("maps") mim_array = {
> +       .type = BPF_MAP_TYPE_ARRAY_OF_MAPS,
> +       .key_size = sizeof(int),
> +       /* must be sizeof(__u32) for map in map */
> +       .value_size = sizeof(__u32),
> +       .max_entries = 1,
> +       .map_flags = 0,
> +};
> +
> +struct bpf_map_def SEC("maps") mim_hash = {
> +       .type = BPF_MAP_TYPE_HASH_OF_MAPS,
> +       .key_size = sizeof(int),
> +       /* must be sizeof(__u32) for map in map */
> +       .value_size = sizeof(__u32),
> +       .max_entries = 1,
> +       .map_flags = 0,
> +};
> +
> +
> +
nit: extra new lines.
> +SEC("xdp_mimtest")
> +int xdp_mimtest0(struct xdp_md *ctx)
> +{
> +       int value = 123;
> +       int key = 0;
> +       void *map;
> +
> +       map = bpf_map_lookup_elem(&mim_array, &key);
> +       if (!map)
> +               return XDP_DROP;
> +
> +       bpf_map_update_elem(map, &key, &value, 0);
> +
> +       map = bpf_map_lookup_elem(&mim_hash, &key);
> +       if (!map)
> +               return XDP_DROP;
> +
> +       bpf_map_update_elem(map, &key, &value, 0);
> +
> +       return XDP_PASS;
> +}
> +
> +
nit: extra new line
> +int _version SEC("version") = 1;
> +char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c
> index 4db2116e52be..a49ab294971d 100644
> --- a/tools/testing/selftests/bpf/test_maps.c
> +++ b/tools/testing/selftests/bpf/test_maps.c
> @@ -1080,6 +1080,80 @@ static void test_sockmap(int tasks, void *data)
>         exit(1);
>  }
>
> +#define MAPINMAP_PROG "./test_mapinmap.o"
> +static void test_mapinmap(void)
> +{
> +       struct bpf_program *prog;
> +       struct bpf_object *obj;
> +       struct bpf_map *map;
> +       int mim_fd, fd;
> +       int pos = 0;
> +
> +       obj = bpf_object__open(MAPINMAP_PROG);
> +
> +       fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(int), sizeof(int),
> +                           2, 0);
> +       if (fd < 0) {
> +               printf("Failed to create hashmap '%s'!\n", strerror(errno));
> +               exit(1);
> +       }
> +       printf("fd is %d\n", fd);
not sure whether you need to print fd in the console or not. Any particular
reason?
> +
> +       map = bpf_object__find_map_by_name(obj, "mim_array");
> +       if (IS_ERR(map)) {
> +               printf("Failed to load array of maps from test prog\n");
> +               goto out_mapinmap;
> +       }
> +       bpf_map__add_inner_map_fd(map, fd);
> +
> +       map = bpf_object__find_map_by_name(obj, "mim_hash");
> +       if (IS_ERR(map)) {
> +               printf("Failed to load hash of maps from test prog\n");
> +               goto out_mapinmap;
> +       }
> +       bpf_map__add_inner_map_fd(map, fd);
> +
> +
nit: extra new line
> +       bpf_object__for_each_program(prog, obj) {
> +               bpf_program__set_xdp(prog);
> +       }
> +       bpf_object__load(obj);
> +
> +       map = bpf_object__find_map_by_name(obj, "mim_array");
> +       if (IS_ERR(map)) {
> +               printf("Failed to load array of maps from test prog\n");
> +               goto out_mapinmap;
> +       }
> +       mim_fd = bpf_map__fd(map);
> +       if (mim_fd < 0) {
> +               printf("Failed to get descriptor for array of maps\n");
> +               goto out_mapinmap;
> +       }
> +
> +       bpf_map_update_elem(mim_fd, &pos, &fd, 0);
do you want to test return value of bpf_map_update_elem() to make sure
update is successful?
> +
> +       map = bpf_object__find_map_by_name(obj, "mim_hash");
> +       if (IS_ERR(map)) {
> +               printf("Failed to load hash of maps from test prog\n");
> +               goto out_mapinmap;
> +       }
> +       mim_fd = bpf_map__fd(map);
> +       if (mim_fd < 0) {
> +               printf("Failed to get descriptor for hash of maps\n");
> +               goto out_mapinmap;
> +       }
> +       bpf_map_update_elem(mim_fd, &pos, &fd, 0);
do you want to test return value of bpf_map_update_elem()?
> +
> +
nit: extra new line
> +       close(fd);
> +       bpf_object__close(obj);
> +       return;
> +
> +out_mapinmap:
> +       close(fd);
> +       exit(1);
> +}
> +
>  #define MAP_SIZE (32 * 1024)
>
>  static void test_map_large(void)
> @@ -1554,6 +1628,8 @@ static void run_all_tests(void)
>
>         test_queuemap(0, NULL);
>         test_stackmap(0, NULL);
> +
> +       test_mapinmap();
>  }
>
>  int main(void)
> --
> 2.15.1
>