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