On 2/25/21 3:25 PM, Andrii Nakryiko wrote:

On Thu, Feb 25, 2021 at 1:35 AM Yonghong Song [off-list ref] wrote:

quoted

A test case is added for hashmap and percpu hashmap. The test
also exercises nested bpf_for_each_map_elem() calls like
     bpf_prog:
       bpf_for_each_map_elem(func1)
     func1:
       bpf_for_each_map_elem(func2)
     func2:

   $ ./test_progs -n 45
   #45/1 hash_map:OK
   #45 for_each:OK
   Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Yonghong Song <redacted>
---

I think I'll just add all the variants of ASSERT_XXX and will enforce
their use :)

For now:

Acked-by: Andrii Nakryiko <andrii@kernel.org>

quoted

  .../selftests/bpf/prog_tests/for_each.c       | 74 +++++++++++++++
  .../bpf/progs/for_each_hash_map_elem.c        | 95 +++++++++++++++++++
  2 files changed, 169 insertions(+)
  create mode 100644 tools/testing/selftests/bpf/prog_tests/for_each.c
  create mode 100644 tools/testing/selftests/bpf/progs/for_each_hash_map_elem.c

[...]

quoted

+
+       ASSERT_EQ(skel->bss->hashmap_output, 4, "hashmap_output");
+       ASSERT_EQ(skel->bss->hashmap_elems, max_entries, "hashmap_elems");
+
+       key = 1;
+       err = bpf_map_lookup_elem(hashmap_fd, &key, &val);
+       ASSERT_ERR(err, "hashmap_lookup");
+
+       ASSERT_EQ(skel->bss->percpu_called, 1, "percpu_called");
+       ASSERT_EQ(skel->bss->cpu < num_cpus, 1, "num_cpus");

well, this is cheating (it will print something like "0 != 1" on
error) :) why didn't you just add ASSERT_LT?

quoted

+       ASSERT_EQ(skel->bss->percpu_map_elems, 1, "percpu_map_elems");
+       ASSERT_EQ(skel->bss->percpu_key, 1, "percpu_key");
+       ASSERT_EQ(skel->bss->percpu_val, skel->bss->cpu + 1, "percpu_val");
+       ASSERT_EQ(skel->bss->percpu_output, 100, "percpu_output");
+out:
+       free(percpu_valbuf);
+       for_each_hash_map_elem__destroy(skel);
+}
+
+void test_for_each(void)
+{
+       if (test__start_subtest("hash_map"))
+               test_hash_map();
+}

[...]

quoted

+int hashmap_output = 0;
+int hashmap_elems = 0;
+int percpu_map_elems = 0;
+
+SEC("classifier/")

nit: just "classifier" didn't work?

from libbpf.c, I think it should work. Will remove "/"
if it does work!

quoted

+int test_pkt_access(struct __sk_buff *skb)
+{
+       struct callback_ctx data;
+
+       data.ctx = skb;
+       data.input = 10;
+       data.output = 0;
+       hashmap_elems = bpf_for_each_map_elem(&hashmap, check_hash_elem, &data, 0);
+       hashmap_output = data.output;
+
+       percpu_map_elems = bpf_for_each_map_elem(&percpu_map, check_percpu_elem,
+                                                (void *)0, 0);
+       return 0;
+}
--
2.24.1