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