selftests/bpf: abstract away test log output

This patch changes how test output is printed out. By default, if test
had no errors, the only output will be a single line with test number,
name, and verdict at the end, e.g.:

  #31 xdp:OK

If test had any errors, all log output captured during test execution
will be output after test completes.

It's possible to force output of log with `-v` (`--verbose`) option, in
which case output won't be buffered and will be output immediately.

To support this, individual tests are required to use helper methods for
logging: `test__printf()` and `test__vprintf()`.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/map_lock.c b/tools/testing/selftests/bpf/prog_tests/map_lock.c
index ee99368c595c..2e78217ed3fd 100644
--- a/tools/testing/selftests/bpf/prog_tests/map_lock.c
+++ b/tools/testing/selftests/bpf/prog_tests/map_lock.c
@@ -9,12 +9,12 @@ static void *parallel_map_access(void *arg)
 	for (i = 0; i < 10000; i++) {
 		err = bpf_map_lookup_elem_flags(map_fd, &key, vars, BPF_F_LOCK);
 		if (err) {
-			printf("lookup failed\n");
+			test__printf("lookup failed\n");
 			error_cnt++;
 			goto out;
 		}
 		if (vars[0] != 0) {
-			printf("lookup #%d var[0]=%d\n", i, vars[0]);
+			test__printf("lookup #%d var[0]=%d\n", i, vars[0]);
 			error_cnt++;
 			goto out;
 		}
@@ -22,8 +22,8 @@ static void *parallel_map_access(void *arg)
 		for (j = 2; j < 17; j++) {
 			if (vars[j] == rnd)
 				continue;
-			printf("lookup #%d var[1]=%d var[%d]=%d\n",
-			       i, rnd, j, vars[j]);
+			test__printf("lookup #%d var[1]=%d var[%d]=%d\n",
+				     i, rnd, j, vars[j]);
 			error_cnt++;
 			goto out;
 		}
@@ -43,7 +43,7 @@ void test_map_lock(void)
 
 	err = bpf_prog_load(file, BPF_PROG_TYPE_CGROUP_SKB, &obj, &prog_fd);
 	if (err) {
-		printf("test_map_lock:bpf_prog_load errno %d\n", errno);
+		test__printf("test_map_lock:bpf_prog_load errno %d\n", errno);
 		goto close_prog;
 	}
 	map_fd[0] = bpf_find_map(__func__, obj, "hash_map");