projects / mirror_zfs-debian.git / blame
| Commit | Line | Data |
|---|---|---|
| 34dc7c2f BB |
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 (the "License"). | |
| 6 | * You may not use this file except in compliance with the License. | |
| 7 | * | |
| 8 | * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE | |
| 9 | * or http://www.opensolaris.org/os/licensing. | |
| 10 | * See the License for the specific language governing permissions | |
| 11 | * and limitations under the License. | |
| 12 | * | |
| 13 | * When distributing Covered Code, include this CDDL HEADER in each | |
| 14 | * file and include the License file at usr/src/OPENSOLARIS.LICENSE. | |
| 15 | * If applicable, add the following below this CDDL HEADER, with the | |
| 16 | * fields enclosed by brackets "[]" replaced with your own identifying | |
| 17 | * information: Portions Copyright [yyyy] [name of copyright owner] | |
| 18 | * | |
| 19 | * CDDL HEADER END | |
| 20 | */ | |
| 21 | /* | |
| 22 | * Copyright 2007 Sun Microsystems, Inc. All rights reserved. | |
| 23 | * Use is subject to license terms. | |
| 24 | */ | |
| 25 | ||
| b128c09f | 26 | #pragma ident "%Z%%M% %I% %E% SMI" |
| 34dc7c2f BB |
27 | |
| 28 | #include <sys/zfs_context.h> | |
| 29 | #include <sys/avl.h> | |
| 30 | #include <sys/unique.h> | |
| 31 | ||
| 32 | static avl_tree_t unique_avl; | |
| 33 | static kmutex_t unique_mtx; | |
| 34 | ||
| 35 | typedef struct unique { | |
| 36 | avl_node_t un_link; | |
| 37 | uint64_t un_value; | |
| 38 | } unique_t; | |
| 39 | ||
| 40 | #define UNIQUE_MASK ((1ULL << UNIQUE_BITS) - 1) | |
| 41 | ||
| 42 | static int | |
| 43 | unique_compare(const void *a, const void *b) | |
| 44 | { | |
| 45 | const unique_t *una = a; | |
| 46 | const unique_t *unb = b; | |
| 47 | ||
| 48 | if (una->un_value < unb->un_value) | |
| 49 | return (-1); | |
| 50 | if (una->un_value > unb->un_value) | |
| 51 | return (+1); | |
| 52 | return (0); | |
| 53 | } | |
| 54 | ||
| 55 | void | |
| 56 | unique_init(void) | |
| 57 | { | |
| 58 | avl_create(&unique_avl, unique_compare, | |
| 59 | sizeof (unique_t), offsetof(unique_t, un_link)); | |
| 60 | mutex_init(&unique_mtx, NULL, MUTEX_DEFAULT, NULL); | |
| 61 | } | |
| 62 | ||
| 63 | void | |
| 64 | unique_fini(void) | |
| 65 | { | |
| 66 | avl_destroy(&unique_avl); | |
| 67 | mutex_destroy(&unique_mtx); | |
| 68 | } | |
| 69 | ||
| 70 | uint64_t | |
| 71 | unique_create(void) | |
| 72 | { | |
| 73 | uint64_t value = unique_insert(0); | |
| 74 | unique_remove(value); | |
| 75 | return (value); | |
| 76 | } | |
| 77 | ||
| 78 | uint64_t | |
| 79 | unique_insert(uint64_t value) | |
| 80 | { | |
| 81 | avl_index_t idx; | |
| 82 | unique_t *un = kmem_alloc(sizeof (unique_t), KM_SLEEP); | |
| 83 | ||
| 84 | un->un_value = value; | |
| 85 | ||
| 86 | mutex_enter(&unique_mtx); | |
| 87 | while (un->un_value == 0 || un->un_value & ~UNIQUE_MASK || | |
| 88 | avl_find(&unique_avl, un, &idx)) { | |
| 89 | mutex_exit(&unique_mtx); | |
| 90 | (void) random_get_pseudo_bytes((void*)&un->un_value, | |
| 91 | sizeof (un->un_value)); | |
| 92 | un->un_value &= UNIQUE_MASK; | |
| 93 | mutex_enter(&unique_mtx); | |
| 94 | } | |
| 95 | ||
| 96 | avl_insert(&unique_avl, un, idx); | |
| 97 | mutex_exit(&unique_mtx); | |
| 98 | ||
| 99 | return (un->un_value); | |
| 100 | } | |
| 101 | ||
| 102 | void | |
| 103 | unique_remove(uint64_t value) | |
| 104 | { | |
| 105 | unique_t un_tofind; | |
| 106 | unique_t *un; | |
| 107 | ||
| 108 | un_tofind.un_value = value; | |
| 109 | mutex_enter(&unique_mtx); | |
| 110 | un = avl_find(&unique_avl, &un_tofind, NULL); | |
| 111 | if (un != NULL) { | |
| 112 | avl_remove(&unique_avl, un); | |
| 113 | kmem_free(un, sizeof (unique_t)); | |
| 114 | } | |
| 115 | mutex_exit(&unique_mtx); | |
| 116 | } |