1789Sahrens /* 2789Sahrens * CDDL HEADER START 3789Sahrens * 4789Sahrens * The contents of this file are subject to the terms of the 52856Snd150628 * Common Development and Distribution License (the "License"). 62856Snd150628 * You may not use this file except in compliance with the License. 7789Sahrens * 8789Sahrens * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9789Sahrens * or http://www.opensolaris.org/os/licensing. 10789Sahrens * See the License for the specific language governing permissions 11789Sahrens * and limitations under the License. 12789Sahrens * 13789Sahrens * When distributing Covered Code, include this CDDL HEADER in each 14789Sahrens * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15789Sahrens * If applicable, add the following below this CDDL HEADER, with the 16789Sahrens * fields enclosed by brackets "[]" replaced with your own identifying 17789Sahrens * information: Portions Copyright [yyyy] [name of copyright owner] 18789Sahrens * 19789Sahrens * CDDL HEADER END 20789Sahrens */ 21789Sahrens /* 22*4787Sahrens * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23789Sahrens * Use is subject to license terms. 24789Sahrens */ 25789Sahrens 26789Sahrens #pragma ident "%Z%%M% %I% %E% SMI" 27789Sahrens 28789Sahrens #include <sys/zfs_context.h> 29789Sahrens #include <sys/avl.h> 30789Sahrens #include <sys/unique.h> 31789Sahrens 32789Sahrens static avl_tree_t unique_avl; 33*4787Sahrens static kmutex_t unique_mtx; 34789Sahrens 35789Sahrens typedef struct unique { 36789Sahrens avl_node_t un_link; 37789Sahrens uint64_t un_value; 38789Sahrens } unique_t; 39789Sahrens 40789Sahrens #define UNIQUE_MASK ((1ULL << UNIQUE_BITS) - 1) 41789Sahrens 42789Sahrens static int 43789Sahrens unique_compare(const void *a, const void *b) 44789Sahrens { 45789Sahrens const unique_t *una = a; 46789Sahrens const unique_t *unb = b; 47789Sahrens 48789Sahrens if (una->un_value < unb->un_value) 49789Sahrens return (-1); 50789Sahrens if (una->un_value > unb->un_value) 51789Sahrens return (+1); 52789Sahrens return (0); 53789Sahrens } 54789Sahrens 55789Sahrens void 56789Sahrens unique_init(void) 57789Sahrens { 58789Sahrens avl_create(&unique_avl, unique_compare, 59789Sahrens sizeof (unique_t), offsetof(unique_t, un_link)); 60*4787Sahrens mutex_init(&unique_mtx, NULL, MUTEX_DEFAULT, NULL); 61*4787Sahrens } 62*4787Sahrens 63*4787Sahrens void 64*4787Sahrens unique_fini(void) 65*4787Sahrens { 66*4787Sahrens avl_destroy(&unique_avl); 67*4787Sahrens mutex_destroy(&unique_mtx); 68789Sahrens } 69789Sahrens 70789Sahrens uint64_t 71789Sahrens unique_create(void) 72789Sahrens { 73*4787Sahrens uint64_t value = unique_insert(0); 74*4787Sahrens unique_remove(value); 75*4787Sahrens return (value); 76789Sahrens } 77789Sahrens 78789Sahrens uint64_t 79789Sahrens unique_insert(uint64_t value) 80789Sahrens { 81789Sahrens avl_index_t idx; 82789Sahrens unique_t *un = kmem_alloc(sizeof (unique_t), KM_SLEEP); 83789Sahrens 84789Sahrens un->un_value = value; 85789Sahrens 86789Sahrens mutex_enter(&unique_mtx); 87789Sahrens while (un->un_value == 0 || un->un_value & ~UNIQUE_MASK || 88789Sahrens avl_find(&unique_avl, un, &idx)) { 89789Sahrens mutex_exit(&unique_mtx); 90789Sahrens (void) random_get_pseudo_bytes((void*)&un->un_value, 91789Sahrens sizeof (un->un_value)); 92789Sahrens un->un_value &= UNIQUE_MASK; 93789Sahrens mutex_enter(&unique_mtx); 94789Sahrens } 95789Sahrens 96789Sahrens avl_insert(&unique_avl, un, idx); 97789Sahrens mutex_exit(&unique_mtx); 98789Sahrens 99789Sahrens return (un->un_value); 100789Sahrens } 101789Sahrens 102789Sahrens void 103789Sahrens unique_remove(uint64_t value) 104789Sahrens { 105789Sahrens unique_t un_tofind; 106789Sahrens unique_t *un; 107789Sahrens 108789Sahrens un_tofind.un_value = value; 109789Sahrens mutex_enter(&unique_mtx); 110789Sahrens un = avl_find(&unique_avl, &un_tofind, NULL); 111789Sahrens if (un != NULL) { 112789Sahrens avl_remove(&unique_avl, un); 113789Sahrens kmem_free(un, sizeof (unique_t)); 114789Sahrens } 115789Sahrens mutex_exit(&unique_mtx); 116789Sahrens } 117