selftests/bpf: fix incorrect users of create_and_get_cgroup

We have some tests that assume create_and_get_cgroup returns -1 on error
which is incorrect (it returns 0 on error). Since fd might be zero in
general case, change create_and_get_cgroup to return -1 on error
and fix the users that assume 0 on error.

Fixes: f269099a7e7a ("tools/bpf: add a selftest for bpf_get_current_cgroup_id() helper")
Fixes: 7d2c6cfc5411 ("bpf: use --cgroup in test_suite if supplied")

v2:
- instead of fixing the uses that assume -1 on error, convert the users
  that assume 0 on error (fd might be zero in general case)

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c b/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c
index c121cc59f314..9220747c069d 100644
--- a/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c
+++ b/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c
@@ -164,7 +164,7 @@ int main(int argc, char **argv)
 		goto err;
 
 	cgfd = create_and_get_cgroup(CGROUP_PATH);
-	if (!cgfd)
+	if (cgfd < 0)
 		goto err;
 
 	if (join_cgroup(CGROUP_PATH))