C++ simple_unlock函数代码示例

/*
 * Retry wait for CARR_ON for open.
 * No locks may be held.
 * May run on any CPU.
 */
boolean_t char_open_done(
	io_req_t	ior)
{
	register struct tty *tp = (struct tty *)ior->io_dev_ptr;
	spl_t s = spltty();

	simple_lock(&tp->t_lock);
	if ((tp->t_state & TS_ISOPEN) == 0) {
	    queue_delayed_reply(&tp->t_delayed_open, ior, char_open_done);
	    simple_unlock(&tp->t_lock);
	    splx(s);
	    return FALSE;
	}

	tp->t_state |= TS_ISOPEN;
	tp->t_state &= ~TS_WOPEN;

	if (tp->t_mctl)
		(*tp->t_mctl)(tp, TM_RTS, DMBIS);

	simple_unlock(&tp->t_lock);
	splx(s);

	ior->io_error = D_SUCCESS;
	(void) ds_open_done(ior);
	return TRUE;
}

/*
 * Retry wait for output queue emptied, for write.
 * No locks may be held.
 * May run on any CPU.
 */
boolean_t char_write_done(
	register io_req_t	ior)
{
	register struct tty *tp = (struct tty *)ior->io_dev_ptr;
	register spl_t s = spltty();

	simple_lock(&tp->t_lock);
	if (tp->t_outq.c_cc > TTHIWAT(tp) ||
	    (tp->t_state & TS_CARR_ON) == 0) {

	    queue_delayed_reply(&tp->t_delayed_write, ior, char_write_done);
	    simple_unlock(&tp->t_lock);
	    splx(s);
	    return FALSE;
	}
	simple_unlock(&tp->t_lock);
	splx(s);

	if (IP_VALID(ior->io_reply_port)) {
	  (void) (*((ior->io_op & IO_INBAND) ?
		    ds_device_write_reply_inband :
		    ds_device_write_reply))(ior->io_reply_port,
					    ior->io_reply_port_type,
					    ior->io_error,
					    (int) (ior->io_total -
						   ior->io_residual));
	}
	mach_device_deallocate(ior->io_device);
	return TRUE;
}

void
cpu_exit_wait(
	int cpu)
{
    	cpu_data_t	*cdp = cpu_datap(cpu);
	boolean_t	intrs_enabled;
	uint64_t	tsc_timeout;

	/*
	 * Wait until the CPU indicates that it has stopped.
	 * Disable interrupts while the topo lock is held -- arguably
	 * this should always be done but in this instance it can lead to
	 * a timeout if long-running interrupt were to occur here.
	 */
	intrs_enabled = ml_set_interrupts_enabled(FALSE);
	simple_lock(&x86_topo_lock);
	/* Set a generous timeout of several seconds (in TSC ticks) */
	tsc_timeout = rdtsc64() + (10ULL * 1000 * 1000 * 1000);
	while ((cdp->lcpu.state != LCPU_HALT)
	       && (cdp->lcpu.state != LCPU_OFF)
	       && !cdp->lcpu.stopped) {
	    simple_unlock(&x86_topo_lock);
	    ml_set_interrupts_enabled(intrs_enabled);
	    cpu_pause();
	    if (rdtsc64() > tsc_timeout)
		panic("cpu_exit_wait(%d) timeout", cpu);
	    ml_set_interrupts_enabled(FALSE);
	    simple_lock(&x86_topo_lock);
	}
	simple_unlock(&x86_topo_lock);
	ml_set_interrupts_enabled(intrs_enabled);
}

/*
 * dmio_usrreq_done:
 *
 *	Dmover completion callback.
 */
static void
dmio_usrreq_done(struct dmover_request *dreq)
{
	struct dmio_usrreq_state *dus = dreq->dreq_cookie;
	struct dmio_state *ds = dreq->dreq_session->dses_cookie;

	/* We're already at splsoftclock(). */

	simple_lock(&ds->ds_slock);
	TAILQ_REMOVE(&ds->ds_pending, dus, dus_q);
	if (ds->ds_flags & DMIO_STATE_DEAD) {
		ds->ds_nreqs--;
		dmio_usrreq_fini(ds, dus);
		dmover_request_free(dreq);
		if (ds->ds_nreqs == 0) {
			simple_unlock(&ds->ds_slock);
			seldestroy(&ds->ds_selq);
			pool_put(&dmio_state_pool, ds);
			return;
		}
	} else {
		TAILQ_INSERT_TAIL(&ds->ds_complete, dus, dus_q);
		if (ds->ds_flags & DMIO_STATE_READ_WAIT) {
			ds->ds_flags &= ~DMIO_STATE_READ_WAIT;
			wakeup(&ds->ds_complete);
		}
		if (ds->ds_flags & DMIO_STATE_SEL) {
			ds->ds_flags &= ~DMIO_STATE_SEL;
			selnotify(&ds->ds_selq, POLLOUT | POLLWRNORM, 0);
		}
	}
	simple_unlock(&ds->ds_slock);
}

/*
 * Retry wait for characters, for read.
 * No locks may be held.
 * May run on any CPU - does not talk to device driver.
 */
boolean_t char_read_done(
	register io_req_t	ior)
{
	register struct tty *tp = (struct tty *)ior->io_dev_ptr;
	register spl_t s = spltty();

	simple_lock(&tp->t_lock);

	if (tp->t_inq.c_cc <= 0 ||
	    (tp->t_state & TS_CARR_ON) == 0) {

	    queue_delayed_reply(&tp->t_delayed_read, ior, char_read_done);
	    simple_unlock(&tp->t_lock);
	    splx(s);
	    return FALSE;
	}

	ior->io_residual = ior->io_count - q_to_b(&tp->t_inq,
						  ior->io_data,
						  (int)ior->io_count);
	if (tp->t_state & TS_RTS_DOWN) {
	    (*tp->t_mctl)(tp, TM_RTS, DMBIS);
	    tp->t_state &= ~TS_RTS_DOWN;
	}

	simple_unlock(&tp->t_lock);
	splx(s);

	(void) ds_read_done(ior);
	return TRUE;
}

/*
 *	Routine:	lock_try_read_to_write
 *	Function:
 *		Improves a read-only lock to one with
 *		write permission.  If another reader has
 *		already requested an upgrade to a write lock,
 *		the read lock is still held upon return.
 *
 *		Returns FALSE if the upgrade *failed*.
 */
boolean_t lock_try_read_to_write(
	register lock_t	l)
{
	check_simple_locks();
	simple_lock(&l->interlock);

	if (l->thread == current_thread()) {
		/*
		 *	Recursive lock
		 */
		l->read_count--;
		l->recursion_depth++;
		simple_unlock(&l->interlock);
		return TRUE;
	}

	if (l->want_upgrade) {
		simple_unlock(&l->interlock);
		return FALSE;
	}
	l->want_upgrade = TRUE;
	l->read_count--;

	while (l->read_count != 0) {
		l->waiting = TRUE;
		thread_sleep(l,
			simple_lock_addr(l->interlock), FALSE);
		simple_lock(&l->interlock);
	}

	simple_unlock(&l->interlock);
	return TRUE;
}

boolean_t lock_try_write(
	register lock_t	l)
{
	simple_lock(&l->interlock);

	if (l->thread == current_thread()) {
		/*
		 *	Recursive lock
		 */
		l->recursion_depth++;
		simple_unlock(&l->interlock);
		return TRUE;
	}

	if (l->want_write || l->want_upgrade || l->read_count) {
		/*
		 *	Can't get lock.
		 */
		simple_unlock(&l->interlock);
		return FALSE;
	}

	/*
	 *	Have lock.
	 */

	l->want_write = TRUE;
	simple_unlock(&l->interlock);
	return TRUE;
}

void
action_thread(void)
{
	register processor_t	processor;
	spl_t			s;

	thread_swappable(current_act(), FALSE);

	while (TRUE) {
		s = splsched();
		simple_lock(&action_lock);
		while ( !queue_empty(&action_queue)) {
			processor = (processor_t) queue_first(&action_queue);
			queue_remove(&action_queue, processor, processor_t,
				     processor_queue);
			simple_unlock(&action_lock);
			splx(s);

			processor_doaction(processor);

			s = splsched();
			simple_lock(&action_lock);
		}

		assert_wait((event_t) &action_queue, FALSE);
		simple_unlock(&action_lock);
		splx(s);
		counter(c_action_thread_block++);
		thread_block((void (*)(void)) 0);
	}
}

boolean_t
lock_try_read(
	register lock_t	* l)
{
	start_data_node_t  entry = {0};
	unsigned short     trace = 0;
	pc_t		   pc;

        ETAP_STAMP(lock_event_table(l), trace, trace);
        ETAP_CREATE_ENTRY(entry, trace);

	simple_lock(&l->interlock);

	if (l->want_write || l->want_upgrade) {
		simple_unlock(&l->interlock);
                ETAP_DESTROY_ENTRY(entry);
		return(FALSE);
	}

	l->read_count++;

        ETAP_LINK_ENTRY(l, entry, trace);

	simple_unlock(&l->interlock);

        MON_ASSIGN_PC(entry->start_pc, pc, trace);
        ETAP_DURATION_TIMESTAMP(entry, trace);

	return(TRUE);
}

/*
 *	thread_stack_daemon:
 *
 *	Perform stack allocation as required due to
 *	invoke failures.
 */
static void
thread_stack_daemon(void)
{
	thread_t		thread;

	simple_lock(&thread_stack_lock);

	while ((thread = (thread_t)dequeue_head(&thread_stack_queue)) != THREAD_NULL) {
		simple_unlock(&thread_stack_lock);

		stack_alloc(thread);
		
		(void)splsched();
		thread_lock(thread);
		thread_setrun(thread, SCHED_PREEMPT | SCHED_TAILQ);
		thread_unlock(thread);
		(void)spllo();

		simple_lock(&thread_stack_lock);
	}

	assert_wait((event_t)&thread_stack_queue, THREAD_UNINT);
	simple_unlock(&thread_stack_lock);

	thread_block((thread_continue_t)thread_stack_daemon);
	/*NOTREACHED*/
}

kern_return_t
get_sched_statistics( 
		struct _processor_statistics_np *out, 
		uint32_t *count)
{
	processor_t processor;

	if (!sched_stats_active) {
		return KERN_FAILURE;
	}

	simple_lock(&processor_list_lock);
	
	if (*count < (processor_count + 2) * sizeof(struct _processor_statistics_np)) { /* One for RT, one for FS */
		simple_unlock(&processor_list_lock);
		return KERN_FAILURE;
	}

	processor = processor_list;
	while (processor) {
		struct processor_sched_statistics *stats = &processor->processor_data.sched_stats;

		out->ps_cpuid 			= processor->cpu_id;
		out->ps_csw_count 		= stats->csw_count;
		out->ps_preempt_count 		= stats->preempt_count;
		out->ps_preempted_rt_count 	= stats->preempted_rt_count;
		out->ps_preempted_by_rt_count 	= stats->preempted_by_rt_count;
		out->ps_rt_sched_count		= stats->rt_sched_count;
		out->ps_interrupt_count 	= stats->interrupt_count;
		out->ps_ipi_count 		= stats->ipi_count;
		out->ps_timer_pop_count 	= stats->timer_pop_count;
		out->ps_runq_count_sum 		= SCHED(processor_runq_stats_count_sum)(processor);
		out->ps_idle_transitions	= stats->idle_transitions;
		out->ps_quantum_timer_expirations	= stats->quantum_timer_expirations;

		out++;
		processor = processor->processor_list;
	}

	*count = (uint32_t) (processor_count * sizeof(struct _processor_statistics_np));

	simple_unlock(&processor_list_lock);

	/* And include RT Queue information */
	bzero(out, sizeof(*out));
	out->ps_cpuid = (-1);
	out->ps_runq_count_sum = rt_runq.runq_stats.count_sum;
	out++;
	*count += (uint32_t)sizeof(struct _processor_statistics_np);

	/* And include Fair Share Queue information at the end */
	bzero(out, sizeof(*out));
	out->ps_cpuid = (-2);
	out->ps_runq_count_sum = SCHED(fairshare_runq_stats_count_sum)();
	*count += (uint32_t)sizeof(struct _processor_statistics_np);
	
	return KERN_SUCCESS;
}

void lock_write(
	register lock_t	l)
{
	register int	i;

	check_simple_locks();
	simple_lock(&l->interlock);

	if (l->thread == current_thread()) {
		/*
		 *	Recursive lock.
		 */
		l->recursion_depth++;
		simple_unlock(&l->interlock);
		return;
	}

	/*
	 *	Try to acquire the want_write bit.
	 */
	while (l->want_write) {
		if ((i = lock_wait_time) > 0) {
			simple_unlock(&l->interlock);
			while (--i > 0 && l->want_write)
				continue;
			simple_lock(&l->interlock);
		}

		if (l->can_sleep && l->want_write) {
			l->waiting = TRUE;
			thread_sleep(l,
				simple_lock_addr(l->interlock), FALSE);
			simple_lock(&l->interlock);
		}
	}
	l->want_write = TRUE;

	/* Wait for readers (and upgrades) to finish */

	while ((l->read_count != 0) || l->want_upgrade) {
		if ((i = lock_wait_time) > 0) {
			simple_unlock(&l->interlock);
			while (--i > 0 && (l->read_count != 0 ||
					l->want_upgrade))
				continue;
			simple_lock(&l->interlock);
		}

		if (l->can_sleep && (l->read_count != 0 || l->want_upgrade)) {
			l->waiting = TRUE;
			thread_sleep(l,
				simple_lock_addr(l->interlock), FALSE);
			simple_lock(&l->interlock);
		}
	}
	simple_unlock(&l->interlock);
}

/*
 *	Routine:	lock_read_to_write
 *	Function:
 *		Improves a read-only lock to one with
 *		write permission.  If another reader has
 *		already requested an upgrade to a write lock,
 *		no lock is held upon return.
 *
 *		Returns TRUE if the upgrade *failed*.
 */
boolean_t lock_read_to_write(
	register lock_t	l)
{
	register int	i;

	check_simple_locks();
	simple_lock(&l->interlock);

	l->read_count--;

	if (l->thread == current_thread()) {
		/*
		 *	Recursive lock.
		 */
		l->recursion_depth++;
		simple_unlock(&l->interlock);
		return(FALSE);
	}

	if (l->want_upgrade) {
		/*
		 *	Someone else has requested upgrade.
		 *	Since we've released a read lock, wake
		 *	him up.
		 */
		if (l->waiting && (l->read_count == 0)) {
			l->waiting = FALSE;
			thread_wakeup(l);
		}

		simple_unlock(&l->interlock);
		return TRUE;
	}

	l->want_upgrade = TRUE;

	while (l->read_count != 0) {
		if ((i = lock_wait_time) > 0) {
			simple_unlock(&l->interlock);
			while (--i > 0 && l->read_count != 0)
				continue;
			simple_lock(&l->interlock);
		}

		if (l->can_sleep && l->read_count != 0) {
			l->waiting = TRUE;
			thread_sleep(l,
				simple_lock_addr(l->interlock), FALSE);
			simple_lock(&l->interlock);
		}
	}

	simple_unlock(&l->interlock);
	return FALSE;
}

/*
 * dmio_ioctl:
 *
 *	Ioctl file op.
 */
static int
dmio_ioctl(struct file *fp, u_long cmd, void *data)
{
	struct dmio_state *ds = (struct dmio_state *) fp->f_data;
	int error, s;

	switch (cmd) {
	case FIONBIO:
	case FIOASYNC:
		return (0);

	case DMIO_SETFUNC:
	    {
		struct dmio_setfunc *dsf = data;
		struct dmover_session *dses;

		s = splsoftclock();
		simple_lock(&ds->ds_slock);

		if (ds->ds_session != NULL ||
		    (ds->ds_flags & DMIO_STATE_LARVAL) != 0) {
			simple_unlock(&ds->ds_slock);
			splx(s);
			return (EBUSY);
		}

		ds->ds_flags |= DMIO_STATE_LARVAL;

		simple_unlock(&ds->ds_slock);
		splx(s);

		dsf->dsf_name[DMIO_MAX_FUNCNAME - 1] = '\0';
		error = dmover_session_create(dsf->dsf_name, &dses);

		s = splsoftclock();
		simple_lock(&ds->ds_slock);

		if (error == 0) {
			dses->dses_cookie = ds;
			ds->ds_session = dses;
		}
		ds->ds_flags &= ~DMIO_STATE_LARVAL;

		simple_unlock(&ds->ds_slock);
		splx(s);
		break;
	    }

	default:
		error = ENOTTY;
	}

	return (error);
}

static void
rf_RaidIOThread(RF_ThreadArg_t arg)
{
	RF_Raid_t *raidPtr;
	RF_DiskQueueData_t *req;
	int s;

	raidPtr = (RF_Raid_t *) arg;

	s = splbio();
	simple_lock(&(raidPtr->iodone_lock));

	while (!raidPtr->shutdown_raidio) {
		/* if there is nothing to do, then snooze. */
		if (TAILQ_EMPTY(&(raidPtr->iodone)) &&
		    rf_buf_queue_check(raidPtr->raidid)) {
			ltsleep(&(raidPtr->iodone), PRIBIO, "raidiow", 0,
				&(raidPtr->iodone_lock));
		}

		/* Check for deferred parity-map-related work. */
		if (raidPtr->parity_map != NULL) {
			simple_unlock(&(raidPtr->iodone_lock));
			rf_paritymap_checkwork(raidPtr->parity_map);
			simple_lock(&(raidPtr->iodone_lock));
		}

		/* See what I/Os, if any, have arrived */
		while ((req = TAILQ_FIRST(&(raidPtr->iodone))) != NULL) {
			TAILQ_REMOVE(&(raidPtr->iodone), req, iodone_entries);
			simple_unlock(&(raidPtr->iodone_lock));
			rf_DiskIOComplete(req->queue, req, req->error);
			(req->CompleteFunc) (req->argument, req->error);
			simple_lock(&(raidPtr->iodone_lock));
		}

		/* process any pending outgoing IO */
		simple_unlock(&(raidPtr->iodone_lock));
		raidstart(raidPtr);
		simple_lock(&(raidPtr->iodone_lock));

	}

	/* Let rf_ShutdownEngine know that we're done... */
	raidPtr->shutdown_raidio = 0;
	wakeup(&(raidPtr->shutdown_raidio));

	simple_unlock(&(raidPtr->iodone_lock));
	splx(s);

	kthread_exit(0);
}