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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2012, 2015 by Delphix. All rights reserved. 24 */ 25 26 #ifndef _SYS_REFCOUNT_H 27 #define _SYS_REFCOUNT_H 28 29 #include <sys/inttypes.h> 30 #include <sys/list.h> 31 #include <sys/zfs_context.h> 32 33 #ifdef __cplusplus 34 extern "C" { 35 #endif 36 37 /* 38 * If the reference is held only by the calling function and not any 39 * particular object, use FTAG (which is a string) for the holder_tag. 40 * Otherwise, use the object that holds the reference. 41 */ 42 #define FTAG ((char *)(uintptr_t)__func__) 43 44 #ifdef ZFS_DEBUG 45 typedef struct reference { 46 list_node_t ref_link; 47 void *ref_holder; 48 uint64_t ref_number; 49 uint8_t *ref_removed; 50 } reference_t; 51 52 typedef struct refcount { 53 kmutex_t rc_mtx; 54 boolean_t rc_tracked; 55 list_t rc_list; 56 list_t rc_removed; 57 uint64_t rc_count; 58 uint64_t rc_removed_count; 59 } refcount_t; 60 61 /* Note: refcount_t must be initialized with refcount_create[_untracked]() */ 62 63 void refcount_create(refcount_t *rc); 64 void refcount_create_untracked(refcount_t *rc); 65 void refcount_create_tracked(refcount_t *rc); 66 void refcount_destroy(refcount_t *rc); 67 void refcount_destroy_many(refcount_t *rc, uint64_t number); 68 int refcount_is_zero(refcount_t *rc); 69 int64_t refcount_count(refcount_t *rc); 70 int64_t refcount_add(refcount_t *rc, void *holder_tag); 71 int64_t refcount_remove(refcount_t *rc, void *holder_tag); 72 int64_t refcount_add_many(refcount_t *rc, uint64_t number, void *holder_tag); 73 int64_t refcount_remove_many(refcount_t *rc, uint64_t number, void *holder_tag); 74 void refcount_transfer(refcount_t *dst, refcount_t *src); 75 void refcount_transfer_ownership(refcount_t *, void *, void *); 76 boolean_t refcount_held(refcount_t *, void *); 77 boolean_t refcount_not_held(refcount_t *, void *); 78 79 void refcount_init(void); 80 void refcount_fini(void); 81 82 #else /* ZFS_DEBUG */ 83 84 typedef struct refcount { 85 uint64_t rc_count; 86 } refcount_t; 87 88 #define refcount_create(rc) ((rc)->rc_count = 0) 89 #define refcount_create_untracked(rc) ((rc)->rc_count = 0) 90 #define refcount_create_tracked(rc) ((rc)->rc_count = 0) 91 #define refcount_destroy(rc) ((rc)->rc_count = 0) 92 #define refcount_destroy_many(rc, number) ((rc)->rc_count = 0) 93 #define refcount_is_zero(rc) ((rc)->rc_count == 0) 94 #define refcount_count(rc) ((rc)->rc_count) 95 #define refcount_add(rc, holder) atomic_inc_64_nv(&(rc)->rc_count) 96 #define refcount_remove(rc, holder) atomic_dec_64_nv(&(rc)->rc_count) 97 #define refcount_add_many(rc, number, holder) \ 98 atomic_add_64_nv(&(rc)->rc_count, number) 99 #define refcount_remove_many(rc, number, holder) \ 100 atomic_add_64_nv(&(rc)->rc_count, -number) 101 #define refcount_transfer(dst, src) { \ 102 uint64_t __tmp = (src)->rc_count; \ 103 atomic_add_64(&(src)->rc_count, -__tmp); \ 104 atomic_add_64(&(dst)->rc_count, __tmp); \ 105 } 106 #define refcount_transfer_ownership(rc, current_holder, new_holder) (void)0 107 #define refcount_held(rc, holder) ((rc)->rc_count > 0) 108 #define refcount_not_held(rc, holder) (B_TRUE) 109 110 #define refcount_init() 111 #define refcount_fini() 112 113 #endif /* ZFS_DEBUG */ 114 115 #ifdef __cplusplus 116 } 117 #endif 118 119 #endif /* _SYS_REFCOUNT_H */ 120