selftests/bpf: test_xsk: Fix __testapp_validate_traffic()'s return value

__testapp_validate_traffic is supposed to return an integer value that
tells if the test passed (0), failed (-1) or was skiped (2). It actually
returns a boolean in the end. This doesn't harm when the test is
successful but can lead to misinterpretation in case of failure as 1
will be returned instead of -1.

Return TEST_FAILURE (-1) in case of failure, TEST_PASS (0) otherwise.

Reviewed-by: Maciej Fijalkowski <[email protected]>
Signed-off-by: Bastien Curutchet (eBPF Foundation) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: bastien-curutchet

tools/testing/selftests/bpf/test_xsk.c

@@ -1725,7 +1725,10 @@ static int __testapp_validate_traffic(struct test_spec *test, struct ifobject *i
 			testapp_clean_xsk_umem(ifobj2);
 	}
 
-	return !!test->fail;
+	if (test->fail)
+		return TEST_FAILURE;
+
+	return TEST_PASS;
 }
 
 static int testapp_validate_traffic(struct test_spec *test)