selftests/bpf: ringbuf_multi: Use runtime page size

Set bpf table sizes dynamically according to the runtime page size
value.

Do not switch to ASSERT macros, keep CHECK, for consistency with the
rest of the test. Can be a separate cleanup patch.
Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210408061310.95877-8-yauheni.kaliuta@redhat.com

tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c

@@ -41,13 +41,30 @@ static int process_sample(void *ctx, void *data, size_t len)
 void test_ringbuf_multi(void)
 {
 	struct test_ringbuf_multi *skel;
-	struct ring_buffer *ringbuf;
+	struct ring_buffer *ringbuf = NULL;
 	int err;
+	int page_size = getpagesize();
 
-	skel = test_ringbuf_multi__open_and_load();
-	if (CHECK(!skel, "skel_open_load", "skeleton open&load failed\n"))
+	skel = test_ringbuf_multi__open();
+	if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
 		return;
 
+	err = bpf_map__set_max_entries(skel->maps.ringbuf1, page_size);
+	if (CHECK(err != 0, "bpf_map__set_max_entries", "bpf_map__set_max_entries failed\n"))
+		goto cleanup;
+
+	err = bpf_map__set_max_entries(skel->maps.ringbuf2, page_size);
+	if (CHECK(err != 0, "bpf_map__set_max_entries", "bpf_map__set_max_entries failed\n"))
+		goto cleanup;
+
+	err = bpf_map__set_max_entries(bpf_map__inner_map(skel->maps.ringbuf_arr), page_size);
+	if (CHECK(err != 0, "bpf_map__set_max_entries", "bpf_map__set_max_entries failed\n"))
+		goto cleanup;
+
+	err = test_ringbuf_multi__load(skel);
+	if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
+		goto cleanup;
+
 	/* only trigger BPF program for current process */
 	skel->bss->pid = getpid();
 

tools/testing/selftests/bpf/progs/test_ringbuf_multi.c

@@ -15,7 +15,6 @@ struct sample {
 
 struct ringbuf_map {
 	__uint(type, BPF_MAP_TYPE_RINGBUF);
-	__uint(max_entries, 1 << 12);
 } ringbuf1 SEC(".maps"),
   ringbuf2 SEC(".maps");