/*

 * 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 2006 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

#ifndef	_SYS_REFCOUNT_H

#define	_SYS_REFCOUNT_H

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include <sys/inttypes.h>

#include <sys/list.h>

#include <sys/zfs_context.h>

#ifdef	__cplusplus

extern "C" {

#endif

/*

 * If the reference is held only by the calling function and not any

 * particular object, use FTAG (which is a string) for the holder_tag.

 * Otherwise, use the object that holds the reference.

 */

#define	FTAG ((char *)__func__)

#if defined(DEBUG) || !defined(_KERNEL)

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;

/* Note: refcount_t should be initialized to zero before use. */

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_init(void);

void refcount_fini(void);

#else /* 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_init()

#define	refcount_fini()

#endif /* DEBUG */

#ifdef	__cplusplus

}

#endif

#endif /* _SYS_REFCOUNT_H */