[PATCH bpf-next 4/6] selftests/bpf: Allow one single recursion in fentry recursion test

[Yafang Shao]

This is a prepation for replacing prog->active with
test_recursion_{acquire,release}, in which one single recursion in the
process context is allowed. The behavior will be as follows,

SEC("fentry/htab_map_delete_elem")
    pass2++;   <<<< Turn out to be 1 after this operation.
    bpf_map_delete_elem(&hash2, &key);
         SEC("fentry/htab_map_delete_elem")    <<<< not recursion
            pass2++; <<<< Turn out to be 2 after this operation.
            bpf_map_delete_elem(&hash2, &key);
                SEC("fentry/htab_map_delete_elem") <<<< RECURSION

Hence we need to change the selftest to allow it. To be
backward-compatibility, we allow both the old value and the new value
to be expected, so a new helper ASSERT_IN_ARRAY() is introduced.

Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
 tools/testing/selftests/bpf/prog_tests/recursion.c |  7 +++++--
 tools/testing/selftests/bpf/test_progs.h           | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/recursion.c b/tools/testing/selftests/bpf/prog_tests/recursion.c
index 23552d3..dfbed2e 100644
--- a/tools/testing/selftests/bpf/prog_tests/recursion.c
+++ b/tools/testing/selftests/bpf/prog_tests/recursion.c
@@ -8,6 +8,7 @@ void test_recursion(void)
 	struct bpf_prog_info prog_info = {};
 	__u32 prog_info_len = sizeof(prog_info);
 	struct recursion *skel;
+	int expected[2];
 	int key = 0;
 	int err;
 
@@ -27,9 +28,11 @@ void test_recursion(void)
 
 	ASSERT_EQ(skel->bss->pass2, 0, "pass2 == 0");
 	bpf_map_delete_elem(bpf_map__fd(skel->maps.hash2), &key);
-	ASSERT_EQ(skel->bss->pass2, 1, "pass2 == 1");
+	expected[1] = 2;
+	ASSERT_IN_ARRAY(skel->bss->pass2, expected, "pass2 in [0 2]");
 	bpf_map_delete_elem(bpf_map__fd(skel->maps.hash2), &key);
-	ASSERT_EQ(skel->bss->pass2, 2, "pass2 == 2");
+	expected[1] = 4;
+	ASSERT_IN_ARRAY(skel->bss->pass2, expected, "pass2 in [0 4]");
 
 	err = bpf_prog_get_info_by_fd(bpf_program__fd(skel->progs.on_delete),
 				      &prog_info, &prog_info_len);
diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h
index 10ba432..79e96cc 100644
--- a/tools/testing/selftests/bpf/test_progs.h
+++ b/tools/testing/selftests/bpf/test_progs.h
@@ -245,6 +245,25 @@ struct msg {
 	___ok;								\
 })
 
+#define ASSERT_IN_ARRAY(actual, expected, name) ({			\
+	static int duration;						\
+	typeof(actual) ___act = (actual);				\
+	typeof((expected)[0]) * ___exp = (expected);			\
+	bool ___ok = false;						\
+	int i;								\
+									\
+	for (i = 0; i < ARRAY_SIZE(expected); i++) {			\
+		if (___act == ___exp[i]) {				\
+			___ok = true;					\
+			break;						\
+		}							\
+	}								\
+	CHECK(!___ok, (name),						\
+	      "unexpected %s: actual %lld not in array\n",		\
+	      (name), (long long)(___act));				\
+	___ok;								\
+})
+
 #define ASSERT_NEQ(actual, expected, name) ({				\
 	static int duration = 0;					\
 	typeof(actual) ___act = (actual);				\
-- 
1.8.3.1