1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include <sys/zfs_context.h> 30 #include <sys/avl.h> 31 #include <sys/unique.h> 32 33 static avl_tree_t unique_avl; 34 static kmutex_t unique_mtx; 35 36 typedef struct unique { 37 avl_node_t un_link; 38 uint64_t un_value; 39 } unique_t; 40 41 #define UNIQUE_MASK ((1ULL << UNIQUE_BITS) - 1) 42 43 static int 44 unique_compare(const void *a, const void *b) 45 { 46 const unique_t *una = a; 47 const unique_t *unb = b; 48 49 if (una->un_value < unb->un_value) 50 return (-1); 51 if (una->un_value > unb->un_value) 52 return (+1); 53 return (0); 54 } 55 56 void 57 unique_init(void) 58 { 59 avl_create(&unique_avl, unique_compare, 60 sizeof (unique_t), offsetof(unique_t, un_link)); 61 } 62 63 uint64_t 64 unique_create(void) 65 { 66 return (unique_insert(0)); 67 } 68 69 uint64_t 70 unique_insert(uint64_t value) 71 { 72 avl_index_t idx; 73 unique_t *un = kmem_alloc(sizeof (unique_t), KM_SLEEP); 74 75 un->un_value = value; 76 77 mutex_enter(&unique_mtx); 78 while (un->un_value == 0 || un->un_value & ~UNIQUE_MASK || 79 avl_find(&unique_avl, un, &idx)) { 80 mutex_exit(&unique_mtx); 81 (void) random_get_pseudo_bytes((void*)&un->un_value, 82 sizeof (un->un_value)); 83 un->un_value &= UNIQUE_MASK; 84 mutex_enter(&unique_mtx); 85 } 86 87 avl_insert(&unique_avl, un, idx); 88 mutex_exit(&unique_mtx); 89 90 return (un->un_value); 91 } 92 93 void 94 unique_remove(uint64_t value) 95 { 96 unique_t un_tofind; 97 unique_t *un; 98 99 un_tofind.un_value = value; 100 mutex_enter(&unique_mtx); 101 un = avl_find(&unique_avl, &un_tofind, NULL); 102 if (un != NULL) { 103 avl_remove(&unique_avl, un); 104 kmem_free(un, sizeof (unique_t)); 105 } 106 mutex_exit(&unique_mtx); 107 } 108