selftests/bpf: regroup and declare similar kfuncs selftests in an array

Similar to tools/testing/selftests/bpf/prog_tests/dynptr.c:
we declare an array of tests that we run one by one in a for loop.

Followup patches will add more similar-ish tests, so avoid a lot of copy
paste by grouping the declaration in an array.

For light skeletons, we have to rely on the offsetof() macro so we can
statically declare which program we are using.
In the libbpf case, we can rely on bpf_object__find_program_by_name().
So also change the Makefile to generate both light skeletons and normal
ones.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220906151303.2780789-2-benjamin.tissoires@redhat.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/Makefile

@@ -351,11 +351,12 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h		\
 		test_subskeleton.skel.h test_subskeleton_lib.skel.h	\
 		test_usdt.skel.h
 
-LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \
+LSKELS := fentry_test.c fexit_test.c fexit_sleep.c \
 	test_ringbuf.c atomics.c trace_printk.c trace_vprintk.c \
 	map_ptr_kern.c core_kern.c core_kern_overflow.c
 # Generate both light skeleton and libbpf skeleton for these
-LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test_subprog.c
+LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test.c \
+	kfunc_call_test_subprog.c
 SKEL_BLACKLIST += $$(LSKELS)
 
 test_static_linked.skel.h-deps := test_static_linked1.bpf.o test_static_linked2.bpf.o

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

@@ -2,6 +2,7 @@
 /* Copyright (c) 2021 Facebook */
 #include <test_progs.h>
 #include <network_helpers.h>
+#include "kfunc_call_test.skel.h"
 #include "kfunc_call_test.lskel.h"
 #include "kfunc_call_test_subprog.skel.h"
 #include "kfunc_call_test_subprog.lskel.h"
@@ -9,9 +10,31 @@
 
 #include "cap_helpers.h"
 
-static void test_main(void)
+struct kfunc_test_params {
+	const char *prog_name;
+	unsigned long lskel_prog_desc_offset;
+	int retval;
+};
+
+#define TC_TEST(name, __retval) \
+	{ \
+	  .prog_name = #name, \
+	  .lskel_prog_desc_offset = offsetof(struct kfunc_call_test_lskel, progs.name), \
+	  .retval = __retval, \
+	}
+
+static struct kfunc_test_params kfunc_tests[] = {
+	TC_TEST(kfunc_call_test1, 12),
+	TC_TEST(kfunc_call_test2, 3),
+	TC_TEST(kfunc_call_test_ref_btf_id, 0),
+};
+
+static void verify_success(struct kfunc_test_params *param)
 {
-	struct kfunc_call_test_lskel *skel;
+	struct kfunc_call_test_lskel *lskel = NULL;
+	struct bpf_prog_desc *lskel_prog;
+	struct kfunc_call_test *skel;
+	struct bpf_program *prog;
 	int prog_fd, err;
 	LIBBPF_OPTS(bpf_test_run_opts, topts,
 		.data_in = &pkt_v4,
@@ -19,26 +42,53 @@ static void test_main(void)
 		.repeat = 1,
 	);
 
-	skel = kfunc_call_test_lskel__open_and_load();
+	/* first test with normal libbpf */
+	skel = kfunc_call_test__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "skel"))
 		return;
 
-	prog_fd = skel->progs.kfunc_call_test1.prog_fd;
-	err = bpf_prog_test_run_opts(prog_fd, &topts);
-	ASSERT_OK(err, "bpf_prog_test_run(test1)");
-	ASSERT_EQ(topts.retval, 12, "test1-retval");
+	prog = bpf_object__find_program_by_name(skel->obj, param->prog_name);
+	if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+		goto cleanup;
 
-	prog_fd = skel->progs.kfunc_call_test2.prog_fd;
+	prog_fd = bpf_program__fd(prog);
 	err = bpf_prog_test_run_opts(prog_fd, &topts);
-	ASSERT_OK(err, "bpf_prog_test_run(test2)");
-	ASSERT_EQ(topts.retval, 3, "test2-retval");
+	if (!ASSERT_OK(err, param->prog_name))
+		goto cleanup;
+
+	if (!ASSERT_EQ(topts.retval, param->retval, "retval"))
+		goto cleanup;
+
+	/* second test with light skeletons */
+	lskel = kfunc_call_test_lskel__open_and_load();
+	if (!ASSERT_OK_PTR(lskel, "lskel"))
+		goto cleanup;
+
+	lskel_prog = (struct bpf_prog_desc *)((char *)lskel + param->lskel_prog_desc_offset);
 
-	prog_fd = skel->progs.kfunc_call_test_ref_btf_id.prog_fd;
+	prog_fd = lskel_prog->prog_fd;
 	err = bpf_prog_test_run_opts(prog_fd, &topts);
-	ASSERT_OK(err, "bpf_prog_test_run(test_ref_btf_id)");
-	ASSERT_EQ(topts.retval, 0, "test_ref_btf_id-retval");
+	if (!ASSERT_OK(err, param->prog_name))
+		goto cleanup;
+
+	ASSERT_EQ(topts.retval, param->retval, "retval");
+
+cleanup:
+	kfunc_call_test__destroy(skel);
+	if (lskel)
+		kfunc_call_test_lskel__destroy(lskel);
+}
+
+static void test_main(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(kfunc_tests); i++) {
+		if (!test__start_subtest(kfunc_tests[i].prog_name))
+			continue;
 
-	kfunc_call_test_lskel__destroy(skel);
+		verify_success(&kfunc_tests[i]);
+	}
 }
 
 static void test_subprog(void)
@@ -121,8 +171,7 @@ static void test_destructive(void)
 
 void test_kfunc_call(void)
 {
-	if (test__start_subtest("main"))
-		test_main();
+	test_main();
 
 	if (test__start_subtest("subprog"))
 		test_subprog();