| 1 | /* $Id: lock.h 48940 2013-10-07 21:26:19Z vboxsync $ */
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| 2 | /** @file
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| 3 | * Lock.h - Haiku, private locking internals.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2012 Oracle Corporation
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | */
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| 17 |
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| 18 | /*
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| 19 | * This code is based on:
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| 20 | *
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| 21 | * VirtualBox Guest Additions for Haiku.
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| 22 | *
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| 23 | * Copyright 2008-2010, Ingo Weinhold, [email protected].
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| 24 | * Copyright 2002-2009, Axel Dörfler, [email protected].
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| 25 | * Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
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| 26 | * Distributed under the terms of the MIT License.
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| 27 | */
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| 28 |
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| 29 | /** @todo r=ramshankar: Eventually this file should be shipped by Haiku and
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| 30 | * should be removed from the VBox tree. */
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| 31 |
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| 32 | #ifndef _KERNEL_LOCK_H
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| 33 | #define _KERNEL_LOCK_H
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| 34 |
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| 35 | #include <OS.h>
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| 36 |
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| 37 |
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| 38 | struct mutex_waiter;
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| 39 |
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| 40 | typedef struct mutex {
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| 41 | const char* name;
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| 42 | struct mutex_waiter* waiters;
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| 43 | #if KDEBUG
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| 44 | thread_id holder;
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| 45 | #else
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| 46 | int32 count;
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| 47 | uint16 ignore_unlock_count;
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| 48 | #endif
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| 49 | uint8 flags;
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| 50 | } mutex;
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| 51 |
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| 52 | #define MUTEX_FLAG_CLONE_NAME 0x1
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| 53 |
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| 54 |
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| 55 | typedef struct recursive_lock {
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| 56 | mutex lock;
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| 57 | #if !KDEBUG
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| 58 | thread_id holder;
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| 59 | #endif
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| 60 | int recursion;
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| 61 | } recursive_lock;
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| 62 |
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| 63 |
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| 64 | struct rw_lock_waiter;
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| 65 |
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| 66 | typedef struct rw_lock {
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| 67 | const char* name;
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| 68 | struct rw_lock_waiter* waiters;
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| 69 | thread_id holder;
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| 70 | vint32 count;
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| 71 | int32 owner_count;
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| 72 | int16 active_readers;
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| 73 | // Only > 0 while a writer is waiting: number
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| 74 | // of active readers when the first waiting
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| 75 | // writer started waiting.
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| 76 | int16 pending_readers;
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| 77 | // Number of readers that have already
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| 78 | // incremented "count", but have not yet started
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| 79 | // to wait at the time the last writer unlocked.
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| 80 | uint32 flags;
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| 81 | } rw_lock;
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| 82 |
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| 83 | #define RW_LOCK_WRITER_COUNT_BASE 0x10000
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| 84 |
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| 85 | #define RW_LOCK_FLAG_CLONE_NAME 0x1
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| 86 |
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| 87 |
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| 88 | #if KDEBUG
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| 89 | # define KDEBUG_RW_LOCK_DEBUG 0
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| 90 | // Define to 1 if you want to use ASSERT_READ_LOCKED_RW_LOCK().
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| 91 | // The rw_lock will just behave like a recursive locker then.
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| 92 | # define ASSERT_LOCKED_RECURSIVE(r) \
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| 93 | { ASSERT(find_thread(NULL) == (r)->lock.holder); }
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| 94 | # define ASSERT_LOCKED_MUTEX(m) { ASSERT(find_thread(NULL) == (m)->holder); }
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| 95 | # define ASSERT_WRITE_LOCKED_RW_LOCK(l) \
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| 96 | { ASSERT(find_thread(NULL) == (l)->holder); }
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| 97 | # if KDEBUG_RW_LOCK_DEBUG
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| 98 | # define ASSERT_READ_LOCKED_RW_LOCK(l) \
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| 99 | { ASSERT(find_thread(NULL) == (l)->holder); }
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| 100 | # else
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| 101 | # define ASSERT_READ_LOCKED_RW_LOCK(l) do {} while (false)
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| 102 | # endif
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| 103 | #else
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| 104 | # define ASSERT_LOCKED_RECURSIVE(r) do {} while (false)
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| 105 | # define ASSERT_LOCKED_MUTEX(m) do {} while (false)
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| 106 | # define ASSERT_WRITE_LOCKED_RW_LOCK(m) do {} while (false)
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| 107 | # define ASSERT_READ_LOCKED_RW_LOCK(l) do {} while (false)
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| 108 | #endif
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| 109 |
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| 110 |
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| 111 | // static initializers
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| 112 | #if KDEBUG
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| 113 | # define MUTEX_INITIALIZER(name) { name, NULL, -1, 0 }
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| 114 | # define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), 0 }
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| 115 | #else
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| 116 | # define MUTEX_INITIALIZER(name) { name, NULL, 0, 0, 0 }
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| 117 | # define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), -1, 0 }
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| 118 | #endif
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| 119 |
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| 120 | #define RW_LOCK_INITIALIZER(name) { name, NULL, -1, 0, 0, 0 }
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| 121 |
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| 122 |
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| 123 | #if KDEBUG
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| 124 | # define RECURSIVE_LOCK_HOLDER(recursiveLock) ((recursiveLock)->lock.holder)
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| 125 | #else
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| 126 | # define RECURSIVE_LOCK_HOLDER(recursiveLock) ((recursiveLock)->holder)
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| 127 | #endif
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| 128 |
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| 129 |
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| 130 | #ifdef __cplusplus
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| 131 | extern "C" {
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| 132 | #endif
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| 133 |
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| 134 | extern void recursive_lock_init(recursive_lock *lock, const char *name);
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| 135 | // name is *not* cloned nor freed in recursive_lock_destroy()
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| 136 | extern void recursive_lock_init_etc(recursive_lock *lock, const char *name,
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| 137 | uint32 flags);
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| 138 | extern void recursive_lock_destroy(recursive_lock *lock);
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| 139 | extern status_t recursive_lock_lock(recursive_lock *lock);
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| 140 | extern status_t recursive_lock_trylock(recursive_lock *lock);
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| 141 | extern void recursive_lock_unlock(recursive_lock *lock);
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| 142 | extern int32 recursive_lock_get_recursion(recursive_lock *lock);
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| 143 |
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| 144 | extern void rw_lock_init(rw_lock* lock, const char* name);
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| 145 | // name is *not* cloned nor freed in rw_lock_destroy()
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| 146 | extern void rw_lock_init_etc(rw_lock* lock, const char* name, uint32 flags);
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| 147 | extern void rw_lock_destroy(rw_lock* lock);
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| 148 | extern status_t rw_lock_write_lock(rw_lock* lock);
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| 149 |
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| 150 | extern void mutex_init(mutex* lock, const char* name);
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| 151 | // name is *not* cloned nor freed in mutex_destroy()
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| 152 | extern void mutex_init_etc(mutex* lock, const char* name, uint32 flags);
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| 153 | extern void mutex_destroy(mutex* lock);
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| 154 | extern status_t mutex_switch_lock(mutex* from, mutex* to);
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| 155 | // Unlocks "from" and locks "to" such that unlocking and starting to wait
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| 156 | // for the lock is atomically. I.e. if "from" guards the object "to" belongs
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| 157 | // to, the operation is safe as long as "from" is held while destroying
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| 158 | // "to".
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| 159 | extern status_t mutex_switch_from_read_lock(rw_lock* from, mutex* to);
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| 160 | // Like mutex_switch_lock(), just for a switching from a read-locked
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| 161 | // rw_lock.
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| 162 |
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| 163 |
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| 164 | // implementation private:
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| 165 |
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| 166 | extern status_t _rw_lock_read_lock(rw_lock* lock);
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| 167 | extern status_t _rw_lock_read_lock_with_timeout(rw_lock* lock,
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| 168 | uint32 timeoutFlags, bigtime_t timeout);
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| 169 | extern void _rw_lock_read_unlock(rw_lock* lock, bool threadsLocked);
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| 170 | extern void _rw_lock_write_unlock(rw_lock* lock, bool threadsLocked);
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| 171 |
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| 172 | extern status_t _mutex_lock(mutex* lock, bool threadsLocked);
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| 173 | extern void _mutex_unlock(mutex* lock, bool threadsLocked);
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| 174 | extern status_t _mutex_trylock(mutex* lock);
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| 175 | extern status_t _mutex_lock_with_timeout(mutex* lock, uint32 timeoutFlags,
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| 176 | bigtime_t timeout);
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| 177 |
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| 178 |
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| 179 | static inline status_t
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| 180 | rw_lock_read_lock(rw_lock* lock)
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| 181 | {
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| 182 | #if KDEBUG_RW_LOCK_DEBUG
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| 183 | return rw_lock_write_lock(lock);
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| 184 | #else
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| 185 | int32 oldCount = atomic_add(&lock->count, 1);
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| 186 | if (oldCount >= RW_LOCK_WRITER_COUNT_BASE)
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| 187 | return _rw_lock_read_lock(lock);
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| 188 | return B_OK;
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| 189 | #endif
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| 190 | }
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| 191 |
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| 192 |
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| 193 | static inline status_t
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| 194 | rw_lock_read_lock_with_timeout(rw_lock* lock, uint32 timeoutFlags,
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| 195 | bigtime_t timeout)
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| 196 | {
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| 197 | #if KDEBUG_RW_LOCK_DEBUG
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| 198 | return mutex_lock_with_timeout(lock, timeoutFlags, timeout);
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| 199 | #else
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| 200 | int32 oldCount = atomic_add(&lock->count, 1);
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| 201 | if (oldCount >= RW_LOCK_WRITER_COUNT_BASE)
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| 202 | return _rw_lock_read_lock_with_timeout(lock, timeoutFlags, timeout);
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| 203 | return B_OK;
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| 204 | #endif
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| 205 | }
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| 206 |
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| 207 |
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| 208 | static inline void
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| 209 | rw_lock_read_unlock(rw_lock* lock)
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| 210 | {
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| 211 | #if KDEBUG_RW_LOCK_DEBUG
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| 212 | rw_lock_write_unlock(lock);
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| 213 | #else
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| 214 | int32 oldCount = atomic_add(&lock->count, -1);
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| 215 | if (oldCount >= RW_LOCK_WRITER_COUNT_BASE)
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| 216 | _rw_lock_read_unlock(lock, false);
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| 217 | #endif
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| 218 | }
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| 219 |
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| 220 |
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| 221 | static inline void
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| 222 | rw_lock_write_unlock(rw_lock* lock)
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| 223 | {
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| 224 | _rw_lock_write_unlock(lock, false);
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| 225 | }
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| 226 |
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| 227 |
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| 228 | static inline status_t
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| 229 | mutex_lock(mutex* lock)
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| 230 | {
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| 231 | #if KDEBUG
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| 232 | return _mutex_lock(lock, false);
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| 233 | #else
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| 234 | if (atomic_add(&lock->count, -1) < 0)
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| 235 | return _mutex_lock(lock, false);
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| 236 | return B_OK;
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| 237 | #endif
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| 238 | }
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| 239 |
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| 240 |
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| 241 | static inline status_t
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| 242 | mutex_lock_threads_locked(mutex* lock)
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| 243 | {
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| 244 | #if KDEBUG
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| 245 | return _mutex_lock(lock, true);
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| 246 | #else
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| 247 | if (atomic_add(&lock->count, -1) < 0)
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| 248 | return _mutex_lock(lock, true);
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| 249 | return B_OK;
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| 250 | #endif
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| 251 | }
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| 252 |
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| 253 |
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| 254 | static inline status_t
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| 255 | mutex_trylock(mutex* lock)
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| 256 | {
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| 257 | #if KDEBUG
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| 258 | return _mutex_trylock(lock);
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| 259 | #else
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| 260 | if (atomic_test_and_set(&lock->count, -1, 0) != 0)
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| 261 | return B_WOULD_BLOCK;
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| 262 | return B_OK;
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| 263 | #endif
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| 264 | }
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| 265 |
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| 266 |
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| 267 | static inline status_t
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| 268 | mutex_lock_with_timeout(mutex* lock, uint32 timeoutFlags, bigtime_t timeout)
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| 269 | {
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| 270 | #if KDEBUG
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| 271 | return _mutex_lock_with_timeout(lock, timeoutFlags, timeout);
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| 272 | #else
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| 273 | if (atomic_add(&lock->count, -1) < 0)
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| 274 | return _mutex_lock_with_timeout(lock, timeoutFlags, timeout);
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| 275 | return B_OK;
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| 276 | #endif
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| 277 | }
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| 278 |
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| 279 |
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| 280 | static inline void
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| 281 | mutex_unlock(mutex* lock)
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| 282 | {
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| 283 | #if !KDEBUG
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| 284 | if (atomic_add(&lock->count, 1) < -1)
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| 285 | #endif
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| 286 | _mutex_unlock(lock, false);
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| 287 | }
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| 288 |
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| 289 |
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| 290 | static inline void
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| 291 | mutex_transfer_lock(mutex* lock, thread_id thread)
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| 292 | {
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| 293 | #if KDEBUG
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| 294 | lock->holder = thread;
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| 295 | #endif
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| 296 | }
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| 297 |
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| 298 |
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| 299 | extern void lock_debug_init();
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| 300 |
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| 301 | #ifdef __cplusplus
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| 302 | }
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| 303 | #endif
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| 304 |
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| 305 | #endif /* _KERNEL_LOCK_H */
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