[PATCH bpf-next 2/3] selftests/bpf: name the failing registration in bpf_testmod_init

[Wang Yibo <szwyb123@gmail.com>]

bpf_testmod_init() chains its registrations with ret = ret ?: ...;
when one of them fails the module only reports the final error code,
and there is no way to tell which call failed without instrumenting
the code. Wrap the calls in a macro that prints the failing expression
and its return value instead.

Signed-off-by: Wang Yibo <szwyb123@gmail.com>
---
 .../selftests/bpf/test_kmods/bpf_testmod.c    | 41 +++++++++++--------
 1 file changed, 25 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
index 6380f52f4..625b6dc3b 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
@@ -2593,22 +2593,31 @@ static int bpf_testmod_init(void)
 	void **tramp;
 	int ret;
 
-	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &bpf_testmod_common_kfunc_set);
-	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_testmod_kfunc_set);
-	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_testmod_kfunc_set);
-	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_testmod_kfunc_set);
-	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &bpf_testmod_kfunc_set);
-	ret = ret ?: register_btf_fmodret_id_set(&bpf_testmod_trampoline_count_fmodret_set);
-	ret = ret ?: register_bpf_struct_ops(&bpf_bpf_testmod_ops, bpf_testmod_ops);
-	ret = ret ?: register_bpf_struct_ops(&bpf_testmod_ops2, bpf_testmod_ops2);
-	ret = ret ?: register_bpf_struct_ops(&bpf_testmod_ops3, bpf_testmod_ops3);
-	ret = ret ?: register_bpf_struct_ops(&testmod_st_ops, bpf_testmod_st_ops);
-	ret = ret ?: register_bpf_struct_ops(&testmod_multi_st_ops, bpf_testmod_multi_st_ops);
-	ret = ret ?: register_btf_id_dtor_kfuncs(bpf_testmod_dtors,
-						 ARRAY_SIZE(bpf_testmod_dtors),
-						 THIS_MODULE);
-	if (ret < 0)
-		return ret;
+#define TRY(expr)							\
+	do {								\
+		ret = (expr);						\
+		if (ret < 0) {						\
+			pr_err("%s: %s failed, ret %d\n",		\
+			       __func__, #expr, ret);			\
+			return ret;					\
+		}							\
+	} while (0)
+
+	TRY(register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &bpf_testmod_common_kfunc_set));
+	TRY(register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_testmod_kfunc_set));
+	TRY(register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_testmod_kfunc_set));
+	TRY(register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_testmod_kfunc_set));
+	TRY(register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &bpf_testmod_kfunc_set));
+	TRY(register_btf_fmodret_id_set(&bpf_testmod_trampoline_count_fmodret_set));
+	TRY(register_bpf_struct_ops(&bpf_bpf_testmod_ops, bpf_testmod_ops));
+	TRY(register_bpf_struct_ops(&bpf_testmod_ops2, bpf_testmod_ops2));
+	TRY(register_bpf_struct_ops(&bpf_testmod_ops3, bpf_testmod_ops3));
+	TRY(register_bpf_struct_ops(&testmod_st_ops, bpf_testmod_st_ops));
+	TRY(register_bpf_struct_ops(&testmod_multi_st_ops, bpf_testmod_multi_st_ops));
+	TRY(register_btf_id_dtor_kfuncs(bpf_testmod_dtors,
+					ARRAY_SIZE(bpf_testmod_dtors),
+					THIS_MODULE));
+#undef TRY
 	if (bpf_fentry_test1(0) < 0)
 		return -EINVAL;
 	sock = NULL;
-- 
2.51.0