xref: /linux/Documentation/litmus-tests/atomic/cmpxchg-fail-ordered-1.litmus (revision 621cde16e49b3ecf7d59a8106a20aaebfb4a59a9) 
1C cmpxchg-fail-ordered-1
2
3(*
4 * Result: Never
5 *
6 * Demonstrate that a failing cmpxchg() operation will act as a full
7 * barrier when followed by smp_mb__after_atomic().
8 *)
9
10{}
11
12P0(int *x, int *y, int *z)
13{
14	int r0;
15	int r1;
16
17	WRITE_ONCE(*x, 1);
18	r1 = cmpxchg(z, 1, 0);
19	smp_mb__after_atomic();
20	r0 = READ_ONCE(*y);
21}
22
23P1(int *x, int *y, int *z)
24{
25	int r0;
26	int r1;
27
28	WRITE_ONCE(*y, 1);
29	r1 = cmpxchg(z, 1, 0);
30	smp_mb__after_atomic();
31	r0 = READ_ONCE(*x);
32}
33
34locations[0:r1;1:r1]
35exists (0:r0=0 /\ 1:r0=0)
36