static void queue_io(struct mapped_device *md, struct bio *bio)
{
	unsigned long flags;

	spin_lock_irqsave(&md->deferred_lock, flags);
	bio_list_add(&md->deferred, bio);
	spin_unlock_irqrestore(&md->deferred_lock, flags);
	queue_work(md->wq, &md->work);
}
static void queue_io(struct mapped_device *md, struct bio *bio)
{
	unsigned long flags;

	spin_lock_irqsave(&md->deferred_lock, flags);
	bio_list_add(&md->deferred, bio);
	spin_unlock_irqrestore(&md->deferred_lock, flags);
	queue_work(md->wq, &md->work);
}