include/sys/rwlock_impl.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, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #ifndef _SYS_RWLOCK_IMPL_H
  28 #define _SYS_RWLOCK_IMPL_H
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 /*
  33  * Implementation-private definitions for readers/writer locks.
  34  */
  35
  36 #ifndef _ASM
  37
  38 #include <sys/rwlock.h>
  39
  40 #ifdef  __cplusplus
  41 extern "C" {
  42 #endif
  43
  44 typedef struct rwlock_impl {
  45         uintptr_t       rw_wwwh;        /* waiters, write wanted, hold count */
  46 } rwlock_impl_t;
  47
  48 #endif  /* _ASM */
  49
  50 #define RW_HAS_WAITERS          1
  51 #define RW_WRITE_WANTED         2
  52 #define RW_WRITE_LOCKED         4
  53 #define RW_READ_LOCK            8
  54 #define RW_WRITE_LOCK(thread)   ((uintptr_t)(thread) | RW_WRITE_LOCKED)
  55 #define RW_HOLD_COUNT           (-RW_READ_LOCK)
  56 #define RW_HOLD_COUNT_SHIFT     3               /* log2(RW_READ_LOCK) */
  57 #define RW_READ_COUNT           RW_HOLD_COUNT
  58 #define RW_OWNER                RW_HOLD_COUNT
  59 #define RW_LOCKED               RW_HOLD_COUNT
  60 #define RW_WRITE_CLAIMED        (RW_WRITE_LOCKED | RW_WRITE_WANTED)
  61 #define RW_DOUBLE_LOCK          (RW_WRITE_LOCK(0) | RW_READ_LOCK)
  62
  63 /*
  64  * These macros are used by both the implementation of rw_*() routines and
  65  * by the implementation of the rwlock-related DTrace subroutines.  (DTrace
  66  * cannot make calls into the rw_*() routines; it must use the macros.)
  67  */
  68 #define _RW_READ_HELD(rwlp, tmp)                                        \
  69         ((((tmp) = ((rwlock_impl_t *)(rwlp))->rw_wwwh) & RW_LOCKED) &&  \
  70         !((tmp) & RW_WRITE_LOCKED))
  71
  72 #define _RW_WRITE_HELD(rwlp)                                            \
  73         ((((rwlock_impl_t *)(rwlp))->rw_wwwh &                          \
  74         (RW_OWNER | RW_WRITE_LOCKED)) == RW_WRITE_LOCK(curthread))
  75
  76 #define _RW_LOCK_HELD(rwlp)                                             \
  77         ((((rwlock_impl_t *)(rwlp))->rw_wwwh & RW_LOCKED) ? 1 : 0)
  78
  79 #define _RW_ISWRITER(rwlp)                                              \
  80         ((((rwlock_impl_t *)(rwlp))->rw_wwwh & RW_WRITE_CLAIMED) ? 1 : 0)
  81
  82 #ifdef  __cplusplus
  83 }
  84 #endif
  85
  86 #endif  /* _SYS_RWLOCK_IMPL_H */