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// SPDX-License-Identifier: CDDL-1.0
/*
* 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 https://opensource.org/licenses/CDDL-1.0.
* 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_ZFS_REFCOUNT_H
#define _SYS_ZFS_REFCOUNT_H
#include <sys/inttypes.h>
#include <sys/avl.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 *)(uintptr_t)__func__)
#ifdef ZFS_DEBUG
typedef struct reference {
union {
avl_node_t a;
list_node_t l;
} ref_link;
const void *ref_holder;
uint64_t ref_number;
boolean_t ref_search;
} reference_t;
typedef struct refcount {
uint64_t rc_count;
kmutex_t rc_mtx;
avl_tree_t rc_tree;
list_t rc_removed;
uint_t rc_removed_count;
boolean_t rc_tracked;
} zfs_refcount_t;
/*
* Note: zfs_refcount_t must be initialized with
* refcount_create[_untracked]()
*/
void zfs_refcount_create(zfs_refcount_t *);
void zfs_refcount_create_untracked(zfs_refcount_t *);
void zfs_refcount_create_tracked(zfs_refcount_t *);
void zfs_refcount_destroy(zfs_refcount_t *);
void zfs_refcount_destroy_many(zfs_refcount_t *, uint64_t);
int zfs_refcount_is_zero(zfs_refcount_t *);
int64_t zfs_refcount_count(zfs_refcount_t *);
int64_t zfs_refcount_add(zfs_refcount_t *, const void *);
int64_t zfs_refcount_remove(zfs_refcount_t *, const void *);
/*
* Note that (add|remove)_many adds/removes one reference with "number" N,
* _not_ N references with "number" 1, which is what (add|remove)_few does,
* or what vanilla zfs_refcount_(add|remove) called N times would do.
*
* Attempting to remove a reference with number N when none exists is a
* panic on debug kernels with reference_tracking enabled.
*/
void zfs_refcount_add_few(zfs_refcount_t *, uint64_t, const void *);
void zfs_refcount_remove_few(zfs_refcount_t *, uint64_t, const void *);
int64_t zfs_refcount_add_many(zfs_refcount_t *, uint64_t, const void *);
int64_t zfs_refcount_remove_many(zfs_refcount_t *, uint64_t, const void *);
void zfs_refcount_transfer(zfs_refcount_t *, zfs_refcount_t *);
void zfs_refcount_transfer_ownership(zfs_refcount_t *, const void *,
const void *);
void zfs_refcount_transfer_ownership_many(zfs_refcount_t *, uint64_t,
const void *, const void *);
boolean_t zfs_refcount_held(zfs_refcount_t *, const void *);
boolean_t zfs_refcount_not_held(zfs_refcount_t *, const void *);
void zfs_refcount_init(void);
void zfs_refcount_fini(void);
#else /* ZFS_DEBUG */
typedef struct refcount {
uint64_t rc_count;
} zfs_refcount_t;
#define zfs_refcount_create(rc) ((rc)->rc_count = 0)
#define zfs_refcount_create_untracked(rc) ((rc)->rc_count = 0)
#define zfs_refcount_create_tracked(rc) ((rc)->rc_count = 0)
#define zfs_refcount_destroy(rc) ((rc)->rc_count = 0)
#define zfs_refcount_destroy_many(rc, number) ((rc)->rc_count = 0)
#define zfs_refcount_is_zero(rc) (zfs_refcount_count(rc) == 0)
#define zfs_refcount_count(rc) atomic_load_64(&(rc)->rc_count)
#define zfs_refcount_add(rc, holder) atomic_inc_64_nv(&(rc)->rc_count)
#define zfs_refcount_remove(rc, holder) atomic_dec_64_nv(&(rc)->rc_count)
#define zfs_refcount_add_few(rc, number, holder) \
atomic_add_64(&(rc)->rc_count, number)
#define zfs_refcount_remove_few(rc, number, holder) \
atomic_add_64(&(rc)->rc_count, -number)
#define zfs_refcount_add_many(rc, number, holder) \
atomic_add_64_nv(&(rc)->rc_count, number)
#define zfs_refcount_remove_many(rc, number, holder) \
atomic_add_64_nv(&(rc)->rc_count, -number)
#define zfs_refcount_transfer(dst, src) { \
uint64_t __tmp = zfs_refcount_count(src); \
atomic_add_64(&(src)->rc_count, -__tmp); \
atomic_add_64(&(dst)->rc_count, __tmp); \
}
#define zfs_refcount_transfer_ownership(rc, ch, nh) ((void)0)
#define zfs_refcount_transfer_ownership_many(rc, nr, ch, nh) ((void)0)
#define zfs_refcount_held(rc, holder) (zfs_refcount_count(rc) > 0)
#define zfs_refcount_not_held(rc, holder) (B_TRUE)
#define zfs_refcount_init()
#define zfs_refcount_fini()
#endif /* ZFS_DEBUG */
#ifdef __cplusplus
}
#endif
#endif /* _SYS_REFCOUNT_H */
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