selftests/bpf: Correct map_fd to data_fd in tailcalls

Get and check data_fd. It should not check map_fd again.

Meanwhile, correct some 'return' to 'goto out'.

Thank the suggestion from Maciej in "bpf, x64: Fix tailcall infinite
loop"[0] discussions.

[0] https://lore.kernel.org/bpf/e496aef8-1f80-0f8e-dcdd-25a8c300319a@gmail.com/T/#m7d3b601066ba66400d436b7e7579b2df4a101033

Fixes: 79d49ba0 ("bpf, testing: Add various tail call test cases")
Fixes: 3b037911 ("selftests/bpf: Add tailcall_bpf2bpf tests")
Fixes: 5e0b0a4c ("selftests/bpf: Test tail call counting with bpf2bpf and data on stack")
Signed-off-by: Leon Hwang <hffilwlqm@gmail.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/r/20230906154256.95461-1-hffilwlqm@gmail.comSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

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

@@ -271,11 +271,11 @@ static void test_tailcall_count(const char *which)
 
 	data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 	if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
-		return;
+		goto out;
 
 	data_fd = bpf_map__fd(data_map);
-	if (CHECK_FAIL(map_fd < 0))
-		return;
+	if (CHECK_FAIL(data_fd < 0))
+		goto out;
 
 	i = 0;
 	err = bpf_map_lookup_elem(data_fd, &i, &val);
@@ -352,11 +352,11 @@ static void test_tailcall_4(void)
 
 	data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 	if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
-		return;
+		goto out;
 
 	data_fd = bpf_map__fd(data_map);
-	if (CHECK_FAIL(map_fd < 0))
-		return;
+	if (CHECK_FAIL(data_fd < 0))
+		goto out;
 
 	for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 		snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
@@ -442,11 +442,11 @@ static void test_tailcall_5(void)
 
 	data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 	if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
-		return;
+		goto out;
 
 	data_fd = bpf_map__fd(data_map);
-	if (CHECK_FAIL(map_fd < 0))
-		return;
+	if (CHECK_FAIL(data_fd < 0))
+		goto out;
 
 	for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
 		snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
@@ -631,11 +631,11 @@ static void test_tailcall_bpf2bpf_2(void)
 
 	data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 	if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
-		return;
+		goto out;
 
 	data_fd = bpf_map__fd(data_map);
-	if (CHECK_FAIL(map_fd < 0))
-		return;
+	if (CHECK_FAIL(data_fd < 0))
+		goto out;
 
 	i = 0;
 	err = bpf_map_lookup_elem(data_fd, &i, &val);
@@ -805,11 +805,11 @@ static void test_tailcall_bpf2bpf_4(bool noise)
 
 	data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
 	if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
-		return;
+		goto out;
 
 	data_fd = bpf_map__fd(data_map);
-	if (CHECK_FAIL(map_fd < 0))
-		return;
+	if (CHECK_FAIL(data_fd < 0))
+		goto out;
 
 	i = 0;
 	val.noise = noise;
@@ -872,7 +872,7 @@ static void test_tailcall_bpf2bpf_6(void)
 	ASSERT_EQ(topts.retval, 0, "tailcall retval");
 
 	data_fd = bpf_map__fd(obj->maps.bss);
-	if (!ASSERT_GE(map_fd, 0, "bss map fd"))
+	if (!ASSERT_GE(data_fd, 0, "bss map fd"))
 		goto out;
 
 	i = 0;