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
26#ifndef	_SYS_REFCOUNT_H
27#define	_SYS_REFCOUNT_H
28
29#pragma ident	"%Z%%M%	%I%	%E% SMI"
30
31#include <sys/inttypes.h>
32#include <sys/list.h>
33#include <sys/zfs_context.h>
34
35#ifdef	__cplusplus
36extern "C" {
37#endif
38
39/*
40 * If the reference is held only by the calling function and not any
41 * particular object, use FTAG (which is a string) for the holder_tag.
42 * Otherwise, use the object that holds the reference.
43 */
44#define	FTAG ((char *)__func__)
45
46#if defined(DEBUG) || !defined(_KERNEL)
47typedef struct reference {
48	list_node_t ref_link;
49	void *ref_holder;
50	uint64_t ref_number;
51	uint8_t *ref_removed;
52} reference_t;
53
54typedef struct refcount {
55	kmutex_t rc_mtx;
56	list_t rc_list;
57	list_t rc_removed;
58	int64_t rc_count;
59	int64_t rc_removed_count;
60} refcount_t;
61
62/* Note: refcount_t must be initialized with refcount_create() */
63
64void refcount_create(refcount_t *rc);
65void refcount_destroy(refcount_t *rc);
66void refcount_destroy_many(refcount_t *rc, uint64_t number);
67int refcount_is_zero(refcount_t *rc);
68int64_t refcount_count(refcount_t *rc);
69int64_t refcount_add(refcount_t *rc, void *holder_tag);
70int64_t refcount_remove(refcount_t *rc, void *holder_tag);
71int64_t refcount_add_many(refcount_t *rc, uint64_t number, void *holder_tag);
72int64_t refcount_remove_many(refcount_t *rc, uint64_t number, void *holder_tag);
73
74void refcount_init(void);
75void refcount_fini(void);
76
77#else /* DEBUG */
78
79typedef struct refcount {
80	uint64_t rc_count;
81} refcount_t;
82
83#define	refcount_create(rc) ((rc)->rc_count = 0)
84#define	refcount_destroy(rc) ((rc)->rc_count = 0)
85#define	refcount_destroy_many(rc, number) ((rc)->rc_count = 0)
86#define	refcount_is_zero(rc) ((rc)->rc_count == 0)
87#define	refcount_count(rc) ((rc)->rc_count)
88#define	refcount_add(rc, holder) atomic_add_64_nv(&(rc)->rc_count, 1)
89#define	refcount_remove(rc, holder) atomic_add_64_nv(&(rc)->rc_count, -1)
90#define	refcount_add_many(rc, number, holder) \
91	atomic_add_64_nv(&(rc)->rc_count, number)
92#define	refcount_remove_many(rc, number, holder) \
93	atomic_add_64_nv(&(rc)->rc_count, -number)
94
95#define	refcount_init()
96#define	refcount_fini()
97
98#endif /* DEBUG */
99
100#ifdef	__cplusplus
101}
102#endif
103
104#endif /* _SYS_REFCOUNT_H */
105