fa9e4066f08beec538e775443c5be79dd423fcabahrens/*
fa9e4066f08beec538e775443c5be79dd423fcabahrens * CDDL HEADER START
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * The contents of this file are subject to the terms of the
5ad820458efd0fdb914baff9c1447c22b819fa23nd * Common Development and Distribution License (the "License").
5ad820458efd0fdb914baff9c1447c22b819fa23nd * You may not use this file except in compliance with the License.
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
fa9e4066f08beec538e775443c5be79dd423fcabahrens * or http://www.opensolaris.org/os/licensing.
fa9e4066f08beec538e775443c5be79dd423fcabahrens * See the License for the specific language governing permissions
fa9e4066f08beec538e775443c5be79dd423fcabahrens * and limitations under the License.
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * When distributing Covered Code, include this CDDL HEADER in each
fa9e4066f08beec538e775443c5be79dd423fcabahrens * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
fa9e4066f08beec538e775443c5be79dd423fcabahrens * If applicable, add the following below this CDDL HEADER, with the
fa9e4066f08beec538e775443c5be79dd423fcabahrens * fields enclosed by brackets "[]" replaced with your own identifying
fa9e4066f08beec538e775443c5be79dd423fcabahrens * information: Portions Copyright [yyyy] [name of copyright owner]
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * CDDL HEADER END
fa9e4066f08beec538e775443c5be79dd423fcabahrens */
fa9e4066f08beec538e775443c5be79dd423fcabahrens/*
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
fa9e4066f08beec538e775443c5be79dd423fcabahrens * Use is subject to license terms.
fa9e4066f08beec538e775443c5be79dd423fcabahrens */
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens#pragma ident "%Z%%M% %I% %E% SMI"
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/zfs_context.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/avl.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/unique.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensstatic avl_tree_t unique_avl;
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrensstatic kmutex_t unique_mtx;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrenstypedef struct unique {
fa9e4066f08beec538e775443c5be79dd423fcabahrens avl_node_t un_link;
fa9e4066f08beec538e775443c5be79dd423fcabahrens uint64_t un_value;
fa9e4066f08beec538e775443c5be79dd423fcabahrens} unique_t;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens#define UNIQUE_MASK ((1ULL << UNIQUE_BITS) - 1)
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensstatic int
fa9e4066f08beec538e775443c5be79dd423fcabahrensunique_compare(const void *a, const void *b)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens const unique_t *una = a;
fa9e4066f08beec538e775443c5be79dd423fcabahrens const unique_t *unb = b;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens if (una->un_value < unb->un_value)
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (-1);
fa9e4066f08beec538e775443c5be79dd423fcabahrens if (una->un_value > unb->un_value)
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (+1);
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (0);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensvoid
fa9e4066f08beec538e775443c5be79dd423fcabahrensunique_init(void)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens avl_create(&unique_avl, unique_compare,
fa9e4066f08beec538e775443c5be79dd423fcabahrens sizeof (unique_t), offsetof(unique_t, un_link));
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens mutex_init(&unique_mtx, NULL, MUTEX_DEFAULT, NULL);
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens}
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrensvoid
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrensunique_fini(void)
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens{
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens avl_destroy(&unique_avl);
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens mutex_destroy(&unique_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensuint64_t
fa9e4066f08beec538e775443c5be79dd423fcabahrensunique_create(void)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens uint64_t value = unique_insert(0);
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens unique_remove(value);
91ebeef555ce7f899b6270a3c2df47b51f7ad59aahrens return (value);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensuint64_t
fa9e4066f08beec538e775443c5be79dd423fcabahrensunique_insert(uint64_t value)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens avl_index_t idx;
fa9e4066f08beec538e775443c5be79dd423fcabahrens unique_t *un = kmem_alloc(sizeof (unique_t), KM_SLEEP);
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens un->un_value = value;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_enter(&unique_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens while (un->un_value == 0 || un->un_value & ~UNIQUE_MASK ||
fa9e4066f08beec538e775443c5be79dd423fcabahrens avl_find(&unique_avl, un, &idx)) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_exit(&unique_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens (void) random_get_pseudo_bytes((void*)&un->un_value,
fa9e4066f08beec538e775443c5be79dd423fcabahrens sizeof (un->un_value));
fa9e4066f08beec538e775443c5be79dd423fcabahrens un->un_value &= UNIQUE_MASK;
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_enter(&unique_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens avl_insert(&unique_avl, un, idx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_exit(&unique_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens return (un->un_value);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensvoid
fa9e4066f08beec538e775443c5be79dd423fcabahrensunique_remove(uint64_t value)
fa9e4066f08beec538e775443c5be79dd423fcabahrens{
fa9e4066f08beec538e775443c5be79dd423fcabahrens unique_t un_tofind;
fa9e4066f08beec538e775443c5be79dd423fcabahrens unique_t *un;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens un_tofind.un_value = value;
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_enter(&unique_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens un = avl_find(&unique_avl, &un_tofind, NULL);
fa9e4066f08beec538e775443c5be79dd423fcabahrens if (un != NULL) {
fa9e4066f08beec538e775443c5be79dd423fcabahrens avl_remove(&unique_avl, un);
fa9e4066f08beec538e775443c5be79dd423fcabahrens kmem_free(un, sizeof (unique_t));
fa9e4066f08beec538e775443c5be79dd423fcabahrens }
fa9e4066f08beec538e775443c5be79dd423fcabahrens mutex_exit(&unique_mtx);
fa9e4066f08beec538e775443c5be79dd423fcabahrens}