mirror of https://gitee.com/openkylin/linux.git
36 lines
703 B
Plaintext
36 lines
703 B
Plaintext
C MP+polockmbonce+poacquiresilsil
|
|
|
|
(*
|
|
* Result: Never
|
|
*
|
|
* Do spinlocks combined with smp_mb__after_spinlock() provide order
|
|
* to outside observers using spin_is_locked() to sense the lock-held
|
|
* state, ordered by acquire? Note that when the first spin_is_locked()
|
|
* returns false and the second true, we know that the smp_load_acquire()
|
|
* executed before the lock was acquired (loosely speaking).
|
|
*)
|
|
|
|
{
|
|
}
|
|
|
|
P0(spinlock_t *lo, int *x)
|
|
{
|
|
spin_lock(lo);
|
|
smp_mb__after_spinlock();
|
|
WRITE_ONCE(*x, 1);
|
|
spin_unlock(lo);
|
|
}
|
|
|
|
P1(spinlock_t *lo, int *x)
|
|
{
|
|
int r1;
|
|
int r2;
|
|
int r3;
|
|
|
|
r1 = smp_load_acquire(x);
|
|
r2 = spin_is_locked(lo);
|
|
r3 = spin_is_locked(lo);
|
|
}
|
|
|
|
exists (1:r1=1 /\ 1:r2=0 /\ 1:r3=1)
|