static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
				      long delta)
{
	long ret = delta;

	if (!spool)
		return ret;

	spin_lock_irq(&spool->lock);

	if (spool->max_hpages != -1) {		/* maximum size accounting */
		if ((spool->used_hpages + delta) <= spool->max_hpages)
			spool->used_hpages += delta;
		else {
			ret = -ENOMEM;
			goto unlock_ret;
		}
	}

	/* minimum size accounting */
	if (spool->min_hpages != -1 && spool->rsv_hpages) {
		if (delta > spool->rsv_hpages) {
			/*
			 * Asking for more reserves than those already taken on
			 * behalf of subpool.  Return difference.
			 */
			ret = delta - spool->rsv_hpages;
			spool->rsv_hpages = 0;
		} else {
			ret = 0;	/* reserves already accounted for */
			spool->rsv_hpages -= delta;
		}
	}

unlock_ret:
	spin_unlock_irq(&spool->lock);
	return ret;
}
Unknown