/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or https://opensource.org/licenses/CDDL-1.0. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2007 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #include <sys/zfs_context.h> #include <sys/avl.h> #include <sys/unique.h> static avl_tree_t unique_avl; static kmutex_t unique_mtx; typedef struct unique { avl_node_t un_link; uint64_t un_value; } unique_t; #define UNIQUE_MASK ((1ULL << UNIQUE_BITS) - 1) static int unique_compare(const void *a, const void *b) { const unique_t *una = (const unique_t *)a; const unique_t *unb = (const unique_t *)b; return (TREE_CMP(una->un_value, unb->un_value)); } void unique_init(void) { avl_create(&unique_avl, unique_compare, sizeof (unique_t), offsetof(unique_t, un_link)); mutex_init(&unique_mtx, NULL, MUTEX_DEFAULT, NULL); } void unique_fini(void) { avl_destroy(&unique_avl); mutex_destroy(&unique_mtx); } uint64_t unique_create(void) { uint64_t value = unique_insert(0); unique_remove(value); return (value); } uint64_t unique_insert(uint64_t value) { avl_index_t idx; unique_t *un = kmem_alloc(sizeof (unique_t), KM_SLEEP); un->un_value = value; mutex_enter(&unique_mtx); while (un->un_value == 0 || un->un_value & ~UNIQUE_MASK || avl_find(&unique_avl, un, &idx)) { mutex_exit(&unique_mtx); (void) random_get_pseudo_bytes((void*)&un->un_value, sizeof (un->un_value)); un->un_value &= UNIQUE_MASK; mutex_enter(&unique_mtx); } avl_insert(&unique_avl, un, idx); mutex_exit(&unique_mtx); return (un->un_value); } void unique_remove(uint64_t value) { unique_t un_tofind; unique_t *un; un_tofind.un_value = value; mutex_enter(&unique_mtx); un = avl_find(&unique_avl, &un_tofind, NULL); if (un != NULL) { avl_remove(&unique_avl, un); kmem_free(un, sizeof (unique_t)); } mutex_exit(&unique_mtx); }