selftests: bpf: Check that PROG_TEST_RUN repeats as requested

Extend a simple prog_run test to check that PROG_TEST_RUN adheres
to the requested repetitions. Convert it to use BPF skeleton.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210303101816.36774-5-lmb@cloudflare.com

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

@@ -2,12 +2,31 @@
 #include <test_progs.h>
 #include <network_helpers.h>
 
-void test_prog_run_xattr(void)
+#include "test_pkt_access.skel.h"
+
+static const __u32 duration;
+
+static void check_run_cnt(int prog_fd, __u64 run_cnt)
 {
-	const char *file = "./test_pkt_access.o";
-	struct bpf_object *obj;
-	char buf[10];
+	struct bpf_prog_info info = {};
+	__u32 info_len = sizeof(info);
 	int err;
+
+	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
+	if (CHECK(err, "get_prog_info", "failed to get bpf_prog_info for fd %d\n", prog_fd))
+		return;
+
+	CHECK(run_cnt != info.run_cnt, "run_cnt",
+	      "incorrect number of repetitions, want %llu have %llu\n", run_cnt, info.run_cnt);
+}
+
+void test_prog_run_xattr(void)
+{
+	struct test_pkt_access *skel;
+	int err, stats_fd = -1;
+	char buf[10] = {};
+	__u64 run_cnt = 0;
+
 	struct bpf_prog_test_run_attr tattr = {
 		.repeat = 1,
 		.data_in = &pkt_v4,
@@ -16,12 +35,15 @@ void test_prog_run_xattr(void)
 		.data_size_out = 5,
 	};
 
-	err = bpf_prog_load(file, BPF_PROG_TYPE_SCHED_CLS, &obj,
-			    &tattr.prog_fd);
-	if (CHECK_ATTR(err, "load", "err %d errno %d\n", err, errno))
+	stats_fd = bpf_enable_stats(BPF_STATS_RUN_TIME);
+	if (CHECK_ATTR(stats_fd < 0, "enable_stats", "failed %d\n", errno))
 		return;
 
-	memset(buf, 0, sizeof(buf));
+	skel = test_pkt_access__open_and_load();
+	if (CHECK_ATTR(!skel, "open_and_load", "failed\n"))
+		goto cleanup;
+
+	tattr.prog_fd = bpf_program__fd(skel->progs.test_pkt_access);
 
 	err = bpf_prog_test_run_xattr(&tattr);
 	CHECK_ATTR(err != -1 || errno != ENOSPC || tattr.retval, "run",
@@ -34,8 +56,12 @@ void test_prog_run_xattr(void)
 	CHECK_ATTR(buf[5] != 0, "overflow",
 	      "BPF_PROG_TEST_RUN ignored size hint\n");
 
+	run_cnt += tattr.repeat;
+	check_run_cnt(tattr.prog_fd, run_cnt);
+
 	tattr.data_out = NULL;
 	tattr.data_size_out = 0;
+	tattr.repeat = 2;
 	errno = 0;
 
 	err = bpf_prog_test_run_xattr(&tattr);
@@ -46,5 +72,12 @@ void test_prog_run_xattr(void)
 	err = bpf_prog_test_run_xattr(&tattr);
 	CHECK_ATTR(err != -EINVAL, "run_wrong_size_out", "err %d\n", err);
 
-	bpf_object__close(obj);
+	run_cnt += tattr.repeat;
+	check_run_cnt(tattr.prog_fd, run_cnt);
+
+cleanup:
+	if (skel)
+		test_pkt_access__destroy(skel);
+	if (stats_fd != -1)
+		close(stats_fd);
 }