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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.
* Copyright (c) 2012, 2015 by Delphix. All rights reserved.
*/
#ifndef _SYS_REFCOUNT_H
#define _SYS_REFCOUNT_H
#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__)
/*
* Starting with 4.11, torvalds/linux@f405df5, the linux kernel defines a
* refcount_t type of its own. The macro below effectively changes references
* in the ZFS code from refcount_t to zfs_refcount_t at compile time, so that
* existing code need not be altered, reducing conflicts when landing openZFS
* patches.
*/
#define refcount_t zfs_refcount_t
#define refcount_add zfs_refcount_add
#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;
boolean_t rc_tracked;
list_t rc_list;
list_t rc_removed;
uint64_t rc_count;
uint64_t rc_removed_count;
} zfs_refcount_t;
/* Note: refcount_t must be initialized with refcount_create[_untracked]() */
void refcount_create(refcount_t *rc);
void refcount_create_untracked(refcount_t *rc);
void refcount_create_tracked(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 zfs_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_transfer_ownership(refcount_t *, void *, void *);
boolean_t refcount_held(refcount_t *, void *);
boolean_t refcount_not_held(refcount_t *, void *);
void refcount_init(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_create_untracked(rc) ((rc)->rc_count = 0)
#define refcount_create_tracked(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 zfs_refcount_add(rc, holder) atomic_inc_64_nv(&(rc)->rc_count)
#define refcount_remove(rc, holder) atomic_dec_64_nv(&(rc)->rc_count)
#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_transfer_ownership(rc, current_holder, new_holder) (void)0
#define refcount_held(rc, holder) ((rc)->rc_count > 0)
#define refcount_not_held(rc, holder) (B_TRUE)
#define refcount_init()
#define refcount_fini()
#endif /* ZFS_DEBUG */
#ifdef __cplusplus
}
#endif
#endif /* _SYS_REFCOUNT_H */
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