[PATCH bpf-next 4/4] bpf/selftests: add simple selftest for bpf_smc_ops

["D. Wythe" <alibuda@linux.alibaba.com>]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This PATCH adds a tiny selftest for bpf_smc_ops, to verify the ability
to attach and write access.

Follow the steps below to run this test.

make -C tools/testing/selftests/bpf
cd tools/testing/selftests/bpf
sudo ./test_progs -t smc

Results shows:
Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 .../selftests/bpf/prog_tests/test_bpf_smc.c        | 21 +++++++++++
 tools/testing/selftests/bpf/progs/bpf_smc.c        | 44 ++++++++++++++++++++++
 2 files changed, 65 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/test_bpf_smc.c
 create mode 100644 tools/testing/selftests/bpf/progs/bpf_smc.c

diff --git a/tools/testing/selftests/bpf/prog_tests/test_bpf_smc.c b/tools/testing/selftests/bpf/prog_tests/test_bpf_smc.c
new file mode 100644
index 00000000..2299853
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_bpf_smc.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+
+#include "bpf_smc.skel.h"
+
+static void load(void)
+{
+	struct bpf_smc *skel;
+
+	skel = bpf_smc__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "bpf_smc__open_and_load"))
+		return;
+
+	bpf_smc__destroy(skel);
+}
+
+void test_bpf_smc(void)
+{
+	if (test__start_subtest("load"))
+		load();
+}
diff --git a/tools/testing/selftests/bpf/progs/bpf_smc.c b/tools/testing/selftests/bpf/progs/bpf_smc.c
new file mode 100644
index 00000000..ebff477
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_smc.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct smc_bpf_ops_ctx {
+	struct {
+		struct tcp_sock *tp;
+	} set_option;
+	struct {
+		const struct tcp_sock *tp;
+		struct inet_request_sock *ireq;
+		int smc_ok;
+	} set_option_cond;
+};
+
+struct smc_bpf_ops {
+	void (*set_option)(struct smc_bpf_ops_ctx *ctx);
+	void (*set_option_cond)(struct smc_bpf_ops_ctx *ctx);
+};
+
+SEC("struct_ops/bpf_smc_set_tcp_option_cond")
+void BPF_PROG(bpf_smc_set_tcp_option_cond, struct smc_bpf_ops_ctx *arg)
+{
+	arg->set_option_cond.smc_ok = 1;
+}
+
+SEC("struct_ops/bpf_smc_set_tcp_option")
+void BPF_PROG(bpf_smc_set_tcp_option, struct smc_bpf_ops_ctx *arg)
+{
+	struct tcp_sock *tp = arg->set_option.tp;
+
+	tp->syn_smc = 1;
+}
+
+SEC(".struct_ops.link")
+struct smc_bpf_ops sample_smc_bpf_ops = {
+	.set_option         = (void *) bpf_smc_set_tcp_option,
+	.set_option_cond    = (void *) bpf_smc_set_tcp_option_cond,
+};
-- 
1.8.3.1