lwp-futex.c

static inline void qemu_futex_wait(Futex *f, unsigned val)
{
    push(f->targets);

    if (f->val == val) {
        _lwp_park(f);
    }
}

static inline void qemu_futex_wake_all(Futex *f)
{
    _lwp_unpark_all(move(f->targets), f->val);
}

static inline void qemu_futex_post_wake(Futex *f)
{
    if (!f->refs--) {
        free(f);
    }
}

static inline void qemu_futex_ref(Futex *f)
{
    f->refs++;
}

static inline void qemu_futex_unref(Futex *f)
{
    if (!f->refs--) {
        free(f);
    }
}

init(f) {
    qemu_futex_ref(f);
}

wake(f) {
    qemu_futex_ref(f);
    if (xchg(&f->val, SET) == BUSY) {
        qemu_futex_wake_all(f);
    }
    qemu_futex_unref(f);
}

wait(f) {
    f->val = BUSY;
    qemu_futex_wait(f, BUSY);
}

destroy(f) {
    qemu_futex_unref(f);
}