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mtx: add mtx_wait_unlocked

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This commit is contained in:
mjg 2020-08-04 23:00:00 +00:00
parent 3cf4e11179
commit a83b4ff63f
2 changed files with 30 additions and 0 deletions
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29
sys/kern/kern_mutex.c
View File

@ -1275,6 +1275,35 @@ mtx_spin_wait_unlocked(struct mtx *m)
}
}
void
mtx_wait_unlocked(struct mtx *m)
{
struct thread *owner;
uintptr_t v;
KASSERT(m->mtx_lock != MTX_DESTROYED,
("%s() of destroyed mutex %p", __func__, m));
KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
("%s() not a sleep mutex %p (%s)", __func__, m,
m->lock_object.lo_name));
KASSERT(!mtx_owned(m), ("%s() waiting on myself on lock %p (%s)", __func__, m,
m->lock_object.lo_name));
for (;;) {
v = atomic_load_acq_ptr(&m->mtx_lock);
if (v == MTX_UNOWNED) {
break;
}
owner = lv_mtx_owner(v);
if (!TD_IS_RUNNING(owner)) {
mtx_lock(m);
mtx_unlock(m);
break;
}
cpu_spinwait();
}
}
#ifdef DDB
void
db_show_mtx(const struct lock_object *lock)

1
sys/sys/mutex.h
View File

@ -106,6 +106,7 @@ void __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v, int opts,
void __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v);
void __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v);
#endif
void mtx_wait_unlocked(struct mtx *m);
#ifdef SMP
#if LOCK_DEBUG > 0