xref: /linux/Documentation/litmus-tests/atomic/cmpxchg-fail-unordered-1.litmus (revision 621cde16e49b3ecf7d59a8106a20aaebfb4a59a9) 
1C cmpxchg-fail-unordered-1
2
3(*
4 * Result: Sometimes
5 *
6 * Demonstrate that a failing cmpxchg() operation does not act as a
7 * full barrier.  (In contrast, a successful cmpxchg() does act as a
8 * full barrier.)
9 *)
10
11{}
12
13P0(int *x, int *y, int *z)
14{
15	int r0;
16	int r1;
17
18	WRITE_ONCE(*x, 1);
19	r1 = cmpxchg(z, 1, 0);
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	r0 = READ_ONCE(*x);
31}
32
33locations[0:r1;1:r1]
34exists (0:r0=0 /\ 1:r0=0)
35