selftests/bpf: Adding pid filtering for atomics test

This make atomics test able to run in parallel with other tests.
Signed-off-by: Yucong Sun <sunyucong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211006185619.364369-11-fallentree@fb.com

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

@@ -225,6 +225,7 @@ void test_atomics(void)
 		test__skip();
 		goto cleanup;
 	}
+	skel->bss->pid = getpid();
 
 	if (test__start_subtest("add"))
 		test_add(skel);

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

@@ -10,6 +10,8 @@ bool skip_tests __attribute((__section__(".data"))) = false;
 bool skip_tests = true;
 #endif
 
+__u32 pid = 0;
+
 __u64 add64_value = 1;
 __u64 add64_result = 0;
 __u32 add32_value = 1;
@@ -21,6 +23,8 @@ __u64 add_noreturn_value = 1;
 SEC("fentry/bpf_fentry_test1")
 int BPF_PROG(add, int a)
 {
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
 #ifdef ENABLE_ATOMICS_TESTS
 	__u64 add_stack_value = 1;
 
@@ -45,6 +49,8 @@ __s64 sub_noreturn_value = 1;
 SEC("fentry/bpf_fentry_test1")
 int BPF_PROG(sub, int a)
 {
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
 #ifdef ENABLE_ATOMICS_TESTS
 	__u64 sub_stack_value = 1;
 
@@ -67,6 +73,8 @@ __u64 and_noreturn_value = (0x110ull << 32);
 SEC("fentry/bpf_fentry_test1")
 int BPF_PROG(and, int a)
 {
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
 #ifdef ENABLE_ATOMICS_TESTS
 
 	and64_result = __sync_fetch_and_and(&and64_value, 0x011ull << 32);
@@ -86,6 +94,8 @@ __u64 or_noreturn_value = (0x110ull << 32);
 SEC("fentry/bpf_fentry_test1")
 int BPF_PROG(or, int a)
 {
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
 #ifdef ENABLE_ATOMICS_TESTS
 	or64_result = __sync_fetch_and_or(&or64_value, 0x011ull << 32);
 	or32_result = __sync_fetch_and_or(&or32_value, 0x011);
@@ -104,6 +114,8 @@ __u64 xor_noreturn_value = (0x110ull << 32);
 SEC("fentry/bpf_fentry_test1")
 int BPF_PROG(xor, int a)
 {
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
 #ifdef ENABLE_ATOMICS_TESTS
 	xor64_result = __sync_fetch_and_xor(&xor64_value, 0x011ull << 32);
 	xor32_result = __sync_fetch_and_xor(&xor32_value, 0x011);
@@ -123,6 +135,8 @@ __u32 cmpxchg32_result_succeed = 0;
 SEC("fentry/bpf_fentry_test1")
 int BPF_PROG(cmpxchg, int a)
 {
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
 #ifdef ENABLE_ATOMICS_TESTS
 	cmpxchg64_result_fail = __sync_val_compare_and_swap(&cmpxchg64_value, 0, 3);
 	cmpxchg64_result_succeed = __sync_val_compare_and_swap(&cmpxchg64_value, 1, 2);
@@ -142,6 +156,8 @@ __u32 xchg32_result = 0;
 SEC("fentry/bpf_fentry_test1")
 int BPF_PROG(xchg, int a)
 {
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
 #ifdef ENABLE_ATOMICS_TESTS
 	__u64 val64 = 2;
 	__u32 val32 = 2;