sys/refcount.h

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/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#ifndef _SYS_REFCOUNT_H
#define _SYS_REFCOUNT_H

#include <sys/cdefs.h>
#include <sys/types.h>
#include_next <sys/refcount.h>
#include <sys/list.h>
#include <sys/zfs_context.h>

#ifdef  __cplusplus
extern "C" {
#endif

#define FTAG ((char *)__func__)

#ifdef  ZFS_DEBUG
typedef struct reference {
        list_node_t ref_link;
        void *ref_holder;
        uint64_t ref_number;
        uint8_t *ref_removed;
} reference_t;

typedef struct refcount {
        kmutex_t rc_mtx;
        list_t rc_list;
        list_t rc_removed;
        int64_t rc_count;
        int64_t rc_removed_count;
} refcount_t;

void refcount_create(refcount_t *rc);
void refcount_destroy(refcount_t *rc);
void refcount_destroy_many(refcount_t *rc, uint64_t number);
int refcount_is_zero(refcount_t *rc);
int64_t refcount_count(refcount_t *rc);
int64_t refcount_add(refcount_t *rc, void *holder_tag);
int64_t refcount_remove(refcount_t *rc, void *holder_tag);
int64_t refcount_add_many(refcount_t *rc, uint64_t number, void *holder_tag);
int64_t refcount_remove_many(refcount_t *rc, uint64_t number, void *holder_tag);
void refcount_transfer(refcount_t *dst, refcount_t *src);

void refcount_sysinit(void);
void refcount_fini(void);

#else   /* ZFS_DEBUG */

typedef struct refcount {
        uint64_t rc_count;
} refcount_t;

#define refcount_create(rc) ((rc)->rc_count = 0)
#define refcount_destroy(rc) ((rc)->rc_count = 0)
#define refcount_destroy_many(rc, number) ((rc)->rc_count = 0)
#define refcount_is_zero(rc) ((rc)->rc_count == 0)
#define refcount_count(rc) ((rc)->rc_count)
#define refcount_add(rc, holder) atomic_add_64_nv(&(rc)->rc_count, 1)
#define refcount_remove(rc, holder) atomic_add_64_nv(&(rc)->rc_count, -1)
#define refcount_add_many(rc, number, holder) \
        atomic_add_64_nv(&(rc)->rc_count, number)
#define refcount_remove_many(rc, number, holder) \
        atomic_add_64_nv(&(rc)->rc_count, -number)
#define refcount_transfer(dst, src) { \
        uint64_t __tmp = (src)->rc_count; \
        atomic_add_64(&(src)->rc_count, -__tmp); \
        atomic_add_64(&(dst)->rc_count, __tmp); \
}

#define refcount_sysinit()
#define refcount_fini()

#endif  /* ZFS_DEBUG */

#ifdef  __cplusplus
}
#endif

#endif /* _SYS_REFCOUNT_H */