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