bpf: selftests: Add sk_state to bpf_tcp_helpers.h

Add sk_state define to bpf_tcp_helpers.h.  Rename the existing
global variable "sk_state" in the kfunc_call test to "sk_state_res".
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210824173013.3977316-1-kafai@fb.com

tools/testing/selftests/bpf/bpf_tcp_helpers.h

@@ -31,6 +31,7 @@ enum sk_pacing {
 
 struct sock {
 	struct sock_common	__sk_common;
+#define sk_state		__sk_common.skc_state
 	unsigned long		sk_pacing_rate;
 	__u32			sk_pacing_status; /* see enum sk_pacing */
 } __attribute__((preserve_access_index));

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

@@ -44,7 +44,7 @@ static void test_subprog(void)
 	ASSERT_OK(err, "bpf_prog_test_run(test1)");
 	ASSERT_EQ(retval, 10, "test1-retval");
 	ASSERT_NEQ(skel->data->active_res, -1, "active_res");
-	ASSERT_EQ(skel->data->sk_state, BPF_TCP_CLOSE, "sk_state");
+	ASSERT_EQ(skel->data->sk_state_res, BPF_TCP_CLOSE, "sk_state_res");
 
 	kfunc_call_test_subprog__destroy(skel);
 }

tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c

@@ -9,7 +9,7 @@ extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
 				  __u32 c, __u64 d) __ksym;
 extern struct sock *bpf_kfunc_call_test3(struct sock *sk) __ksym;
 int active_res = -1;
-int sk_state = -1;
+int sk_state_res = -1;
 
 int __noinline f1(struct __sk_buff *skb)
 {
@@ -28,7 +28,7 @@ int __noinline f1(struct __sk_buff *skb)
 	if (active)
 		active_res = *active;
 
-	sk_state = bpf_kfunc_call_test3((struct sock *)sk)->__sk_common.skc_state;
+	sk_state_res = bpf_kfunc_call_test3((struct sock *)sk)->sk_state;
 
 	return (__u32)bpf_kfunc_call_test1((struct sock *)sk, 1, 2, 3, 4);
 }