1 | /* $Id: semrw-lockless-generic.cpp 56290 2015-06-09 14:01:31Z vboxsync $ */
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2 | /** @file
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3 | * IPRT - Read-Write Semaphore, Generic, lockless variant.
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2009-2015 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 | * The contents of this file may alternatively be used under the terms
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18 | * of the Common Development and Distribution License Version 1.0
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19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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20 | * VirtualBox OSE distribution, in which case the provisions of the
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21 | * CDDL are applicable instead of those of the GPL.
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22 | *
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23 | * You may elect to license modified versions of this file under the
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24 | * terms and conditions of either the GPL or the CDDL or both.
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25 | */
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26 |
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27 |
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28 | /*******************************************************************************
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29 | * Header Files *
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30 | *******************************************************************************/
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31 | #define RTSEMRW_WITHOUT_REMAPPING
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32 | #define RTASSERT_QUIET
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33 | #include <iprt/semaphore.h>
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34 | #include "internal/iprt.h"
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35 |
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36 | #include <iprt/asm.h>
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37 | #include <iprt/assert.h>
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38 | #include <iprt/err.h>
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39 | #include <iprt/lockvalidator.h>
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40 | #include <iprt/mem.h>
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41 | #include <iprt/thread.h>
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42 |
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43 | #include "internal/magics.h"
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44 | #include "internal/strict.h"
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45 |
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46 |
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47 | /*******************************************************************************
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48 | * Structures and Typedefs *
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49 | *******************************************************************************/
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50 | typedef struct RTSEMRWINTERNAL
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51 | {
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52 | /** Magic value (RTSEMRW_MAGIC). */
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53 | uint32_t volatile u32Magic;
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54 | /** Indicates whether hEvtRead needs resetting. */
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55 | bool volatile fNeedReset;
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56 |
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57 | /** The state variable.
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58 | * All accesses are atomic and it bits are defined like this:
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59 | * Bits 0..14 - cReads.
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60 | * Bit 15 - Unused.
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61 | * Bits 16..31 - cWrites. - doesn't make sense here
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62 | * Bit 31 - fDirection; 0=Read, 1=Write.
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63 | * Bits 32..46 - cWaitingReads
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64 | * Bit 47 - Unused.
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65 | * Bits 48..62 - cWaitingWrites
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66 | * Bit 63 - Unused.
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67 | */
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68 | uint64_t volatile u64State;
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69 | /** The write owner. */
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70 | RTNATIVETHREAD volatile hNativeWriter;
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71 | /** The number of reads made by the current writer. */
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72 | uint32_t volatile cWriterReads;
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73 | /** The number of recursions made by the current writer. (The initial grabbing
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74 | * of the lock counts as the first one.) */
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75 | uint32_t volatile cWriteRecursions;
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76 |
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77 | /** What the writer threads are blocking on. */
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78 | RTSEMEVENT hEvtWrite;
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79 | /** What the read threads are blocking on when waiting for the writer to
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80 | * finish. */
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81 | RTSEMEVENTMULTI hEvtRead;
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82 |
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83 | #ifdef RTSEMRW_STRICT
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84 | /** The validator record for the writer. */
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85 | RTLOCKVALRECEXCL ValidatorWrite;
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86 | /** The validator record for the readers. */
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87 | RTLOCKVALRECSHRD ValidatorRead;
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88 | #endif
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89 | } RTSEMRWINTERNAL;
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90 |
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91 |
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92 | /*******************************************************************************
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93 | * Defined Constants And Macros *
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94 | *******************************************************************************/
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95 | #define RTSEMRW_CNT_BITS 15
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96 | #define RTSEMRW_CNT_MASK UINT64_C(0x00007fff)
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97 |
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98 | #define RTSEMRW_CNT_RD_SHIFT 0
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99 | #define RTSEMRW_CNT_RD_MASK (RTSEMRW_CNT_MASK << RTSEMRW_CNT_RD_SHIFT)
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100 | #define RTSEMRW_CNT_WR_SHIFT 16
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101 | #define RTSEMRW_CNT_WR_MASK (RTSEMRW_CNT_MASK << RTSEMRW_CNT_WR_SHIFT)
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102 | #define RTSEMRW_DIR_SHIFT 31
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103 | #define RTSEMRW_DIR_MASK RT_BIT_64(RTSEMRW_DIR_SHIFT)
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104 | #define RTSEMRW_DIR_READ UINT64_C(0)
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105 | #define RTSEMRW_DIR_WRITE UINT64_C(1)
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106 |
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107 | #define RTSEMRW_WAIT_CNT_RD_SHIFT 32
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108 | #define RTSEMRW_WAIT_CNT_RD_MASK (RTSEMRW_CNT_MASK << RTSEMRW_WAIT_CNT_RD_SHIFT)
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109 | //#define RTSEMRW_WAIT_CNT_WR_SHIFT 48
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110 | //#define RTSEMRW_WAIT_CNT_WR_MASK (RTSEMRW_CNT_MASK << RTSEMRW_WAIT_CNT_WR_SHIFT)
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111 |
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112 |
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113 | RTDECL(int) RTSemRWCreate(PRTSEMRW phRWSem)
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114 | {
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115 | return RTSemRWCreateEx(phRWSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, "RTSemRW");
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116 | }
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117 | RT_EXPORT_SYMBOL(RTSemRWCreate);
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118 |
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119 |
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120 | RTDECL(int) RTSemRWCreateEx(PRTSEMRW phRWSem, uint32_t fFlags,
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121 | RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...)
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122 | {
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123 | AssertReturn(!(fFlags & ~RTSEMRW_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
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124 |
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125 | RTSEMRWINTERNAL *pThis = (RTSEMRWINTERNAL *)RTMemAlloc(sizeof(*pThis));
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126 | if (!pThis)
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127 | return VERR_NO_MEMORY;
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128 |
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129 | int rc = RTSemEventMultiCreate(&pThis->hEvtRead);
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130 | if (RT_SUCCESS(rc))
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131 | {
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132 | rc = RTSemEventCreate(&pThis->hEvtWrite);
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133 | if (RT_SUCCESS(rc))
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134 | {
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135 | pThis->u32Magic = RTSEMRW_MAGIC;
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136 | pThis->u32Padding = 0;
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137 | pThis->u64State = 0;
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138 | pThis->hNativeWriter = NIL_RTNATIVETHREAD;
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139 | pThis->cWriterReads = 0;
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140 | pThis->cWriteRecursions = 0;
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141 | pThis->fNeedReset = false;
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142 | #ifdef RTSEMRW_STRICT
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143 | bool const fLVEnabled = !(fFlags & RTSEMRW_FLAGS_NO_LOCK_VAL);
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144 | if (!pszNameFmt)
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145 | {
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146 | static uint32_t volatile s_iSemRWAnon = 0;
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147 | uint32_t i = ASMAtomicIncU32(&s_iSemRWAnon) - 1;
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148 | RTLockValidatorRecExclInit(&pThis->ValidatorWrite, hClass, uSubClass, pThis,
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149 | fLVEnabled, "RTSemRW-%u", i);
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150 | RTLockValidatorRecSharedInit(&pThis->ValidatorRead, hClass, uSubClass, pThis,
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151 | false /*fSignaller*/, fLVEnabled, "RTSemRW-%u", i);
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152 | }
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153 | else
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154 | {
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155 | va_list va;
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156 | va_start(va, pszNameFmt);
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157 | RTLockValidatorRecExclInitV(&pThis->ValidatorWrite, hClass, uSubClass, pThis,
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158 | fLVEnabled, pszNameFmt, va);
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159 | va_end(va);
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160 | va_start(va, pszNameFmt);
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161 | RTLockValidatorRecSharedInitV(&pThis->ValidatorRead, hClass, uSubClass, pThis,
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162 | false /*fSignaller*/, fLVEnabled, pszNameFmt, va);
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163 | va_end(va);
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164 | }
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165 | RTLockValidatorRecMakeSiblings(&pThis->ValidatorWrite.Core, &pThis->ValidatorRead.Core);
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166 | #endif
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167 |
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168 | *phRWSem = pThis;
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169 | return VINF_SUCCESS;
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170 | }
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171 | RTSemEventMultiDestroy(pThis->hEvtRead);
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172 | }
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173 | return rc;
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174 | }
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175 | RT_EXPORT_SYMBOL(RTSemRWCreateEx);
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176 |
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177 |
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178 | RTDECL(int) RTSemRWDestroy(RTSEMRW hRWSem)
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179 | {
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180 | /*
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181 | * Validate input.
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182 | */
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183 | RTSEMRWINTERNAL *pThis = hRWSem;
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184 | if (pThis == NIL_RTSEMRW)
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185 | return VINF_SUCCESS;
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186 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
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187 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
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188 | Assert(!(ASMAtomicReadU64(&pThis->u64State) & (RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK)));
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189 |
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190 | /*
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191 | * Invalidate the object and free up the resources.
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192 | */
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193 | AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTSEMRW_MAGIC, RTSEMRW_MAGIC), VERR_INVALID_HANDLE);
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194 |
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195 | RTSEMEVENTMULTI hEvtRead;
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196 | ASMAtomicXchgHandle(&pThis->hEvtRead, NIL_RTSEMEVENTMULTI, &hEvtRead);
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197 | int rc = RTSemEventMultiDestroy(hEvtRead);
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198 | AssertRC(rc);
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199 |
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200 | RTSEMEVENT hEvtWrite;
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201 | ASMAtomicXchgHandle(&pThis->hEvtWrite, NIL_RTSEMEVENT, &hEvtWrite);
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202 | rc = RTSemEventDestroy(hEvtWrite);
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203 | AssertRC(rc);
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204 |
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205 | #ifdef RTSEMRW_STRICT
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206 | RTLockValidatorRecSharedDelete(&pThis->ValidatorRead);
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207 | RTLockValidatorRecExclDelete(&pThis->ValidatorWrite);
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208 | #endif
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209 | RTMemFree(pThis);
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210 | return VINF_SUCCESS;
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211 | }
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212 | RT_EXPORT_SYMBOL(RTSemRWDestroy);
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213 |
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214 |
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215 | RTDECL(uint32_t) RTSemRWSetSubClass(RTSEMRW hRWSem, uint32_t uSubClass)
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216 | {
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217 | #ifdef RTSEMRW_STRICT
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218 | /*
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219 | * Validate handle.
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220 | */
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221 | struct RTSEMRWINTERNAL *pThis = hRWSem;
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222 | AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID);
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223 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID);
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224 |
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225 | RTLockValidatorRecSharedSetSubClass(&pThis->ValidatorRead, uSubClass);
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226 | return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorWrite, uSubClass);
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227 | #else
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228 | return RTLOCKVAL_SUB_CLASS_INVALID;
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229 | #endif
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230 | }
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231 | RT_EXPORT_SYMBOL(RTSemRWSetSubClass);
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232 |
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233 |
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234 | static int rtSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos)
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235 | {
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236 | /*
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237 | * Validate input.
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238 | */
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239 | RTSEMRWINTERNAL *pThis = hRWSem;
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240 | if (pThis == NIL_RTSEMRW)
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241 | return VINF_SUCCESS;
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242 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
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243 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
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244 |
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245 | #ifdef RTSEMRW_STRICT
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246 | RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
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247 | if (cMillies > 0)
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248 | {
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249 | int rc9;
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250 | RTNATIVETHREAD hNativeWriter;
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251 | ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
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252 | if (hNativeWriter != NIL_RTTHREAD && hNativeWriter == RTThreadNativeSelf())
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253 | rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, cMillies);
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254 | else
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255 | rc9 = RTLockValidatorRecSharedCheckOrder(&pThis->ValidatorRead, hThreadSelf, pSrcPos, cMillies);
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256 | if (RT_FAILURE(rc9))
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257 | return rc9;
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258 | }
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259 | #endif
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260 |
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261 | /*
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262 | * Get cracking...
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263 | */
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264 | uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
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265 | uint64_t u64OldState = u64State;
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266 |
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267 | for (;;)
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268 | {
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269 | if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT))
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270 | {
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271 | /* It flows in the right direction, try follow it before it changes. */
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272 | uint64_t c = (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT;
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273 | c++;
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274 | Assert(c < RTSEMRW_CNT_MASK / 2);
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275 | u64State &= ~RTSEMRW_CNT_RD_MASK;
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276 | u64State |= c << RTSEMRW_CNT_RD_SHIFT;
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277 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
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278 | {
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279 | #ifdef RTSEMRW_STRICT
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280 | RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
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281 | #endif
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282 | break;
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283 | }
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284 | }
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285 | else if ((u64State & (RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK)) == 0)
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286 | {
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287 | /* Wrong direction, but we're alone here and can simply try switch the direction. */
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288 | u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK | RTSEMRW_DIR_MASK);
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289 | u64State |= (UINT64_C(1) << RTSEMRW_CNT_RD_SHIFT) | (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT);
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290 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
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291 | {
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292 | Assert(!pThis->fNeedReset);
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293 | #ifdef RTSEMRW_STRICT
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294 | RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
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295 | #endif
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296 | break;
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297 | }
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298 | }
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299 | else
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300 | {
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301 | /* Is the writer perhaps doing a read recursion? */
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302 | RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
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303 | RTNATIVETHREAD hNativeWriter;
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304 | ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
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305 | if (hNativeSelf == hNativeWriter)
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306 | {
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307 | #ifdef RTSEMRW_STRICT
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308 | int rc9 = RTLockValidatorRecExclRecursionMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core, pSrcPos);
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309 | if (RT_FAILURE(rc9))
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310 | return rc9;
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311 | #endif
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312 | Assert(pThis->cWriterReads < UINT32_MAX / 2);
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313 | ASMAtomicIncU32(&pThis->cWriterReads);
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314 | return VINF_SUCCESS; /* don't break! */
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315 | }
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316 |
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317 | /* If the timeout is 0, return already. */
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318 | if (!cMillies)
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319 | return VERR_TIMEOUT;
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320 |
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321 | /* Add ourselves to the queue and wait for the direction to change. */
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322 | uint64_t c = (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT;
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323 | c++;
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324 | Assert(c < RTSEMRW_CNT_MASK / 2);
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325 |
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326 | uint64_t cWait = (u64State & RTSEMRW_WAIT_CNT_RD_MASK) >> RTSEMRW_WAIT_CNT_RD_SHIFT;
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327 | cWait++;
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328 | Assert(cWait <= c);
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329 | Assert(cWait < RTSEMRW_CNT_MASK / 2);
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330 |
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331 | u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_WAIT_CNT_RD_MASK);
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332 | u64State |= (c << RTSEMRW_CNT_RD_SHIFT) | (cWait << RTSEMRW_WAIT_CNT_RD_SHIFT);
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333 |
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334 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
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335 | {
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336 | for (uint32_t iLoop = 0; ; iLoop++)
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337 | {
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338 | int rc;
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339 | #ifdef RTSEMRW_STRICT
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340 | rc = RTLockValidatorRecSharedCheckBlocking(&pThis->ValidatorRead, hThreadSelf, pSrcPos, true,
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341 | cMillies, RTTHREADSTATE_RW_READ, false);
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342 | if (RT_SUCCESS(rc))
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343 | #else
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344 | RTTHREAD hThreadSelf = RTThreadSelf();
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345 | RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_READ, false);
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346 | #endif
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347 | {
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348 | if (fInterruptible)
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349 | rc = RTSemEventMultiWaitNoResume(pThis->hEvtRead, cMillies);
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350 | else
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351 | rc = RTSemEventMultiWait(pThis->hEvtRead, cMillies);
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352 | RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ);
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353 | if (pThis->u32Magic != RTSEMRW_MAGIC)
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354 | return VERR_SEM_DESTROYED;
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355 | }
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356 | if (RT_FAILURE(rc))
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357 | {
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358 | /* Decrement the counts and return the error. */
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359 | for (;;)
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360 | {
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361 | u64OldState = u64State = ASMAtomicReadU64(&pThis->u64State);
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362 | c = (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT; Assert(c > 0);
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363 | c--;
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364 | cWait = (u64State & RTSEMRW_WAIT_CNT_RD_MASK) >> RTSEMRW_WAIT_CNT_RD_SHIFT; Assert(cWait > 0);
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365 | cWait--;
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366 | u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_WAIT_CNT_RD_MASK);
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367 | u64State |= (c << RTSEMRW_CNT_RD_SHIFT) | (cWait << RTSEMRW_WAIT_CNT_RD_SHIFT);
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368 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
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369 | break;
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370 | }
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371 | return rc;
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372 | }
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373 |
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374 | Assert(pThis->fNeedReset);
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375 | u64State = ASMAtomicReadU64(&pThis->u64State);
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376 | if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT))
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377 | break;
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378 | AssertMsg(iLoop < 1, ("%u\n", iLoop));
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379 | }
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380 |
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381 | /* Decrement the wait count and maybe reset the semaphore (if we're last). */
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382 | for (;;)
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383 | {
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384 | u64OldState = u64State;
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385 |
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386 | cWait = (u64State & RTSEMRW_WAIT_CNT_RD_MASK) >> RTSEMRW_WAIT_CNT_RD_SHIFT;
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387 | Assert(cWait > 0);
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388 | cWait--;
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389 | u64State &= ~RTSEMRW_WAIT_CNT_RD_MASK;
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390 | u64State |= cWait << RTSEMRW_WAIT_CNT_RD_SHIFT;
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391 |
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392 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
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393 | {
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394 | if (cWait == 0)
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395 | {
|
---|
396 | if (ASMAtomicXchgBool(&pThis->fNeedReset, false))
|
---|
397 | {
|
---|
398 | int rc = RTSemEventMultiReset(pThis->hEvtRead);
|
---|
399 | AssertRCReturn(rc, rc);
|
---|
400 | }
|
---|
401 | }
|
---|
402 | break;
|
---|
403 | }
|
---|
404 | u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
405 | }
|
---|
406 |
|
---|
407 | #ifdef RTSEMRW_STRICT
|
---|
408 | RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
|
---|
409 | #endif
|
---|
410 | break;
|
---|
411 | }
|
---|
412 | }
|
---|
413 |
|
---|
414 | if (pThis->u32Magic != RTSEMRW_MAGIC)
|
---|
415 | return VERR_SEM_DESTROYED;
|
---|
416 |
|
---|
417 | ASMNopPause();
|
---|
418 | u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
419 | u64OldState = u64State;
|
---|
420 | }
|
---|
421 |
|
---|
422 | /* got it! */
|
---|
423 | Assert((ASMAtomicReadU64(&pThis->u64State) & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT));
|
---|
424 | return VINF_SUCCESS;
|
---|
425 |
|
---|
426 | }
|
---|
427 |
|
---|
428 |
|
---|
429 | RTDECL(int) RTSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
|
---|
430 | {
|
---|
431 | #ifndef RTSEMRW_STRICT
|
---|
432 | return rtSemRWRequestRead(hRWSem, cMillies, false, NULL);
|
---|
433 | #else
|
---|
434 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
|
---|
435 | return rtSemRWRequestRead(hRWSem, cMillies, false, &SrcPos);
|
---|
436 | #endif
|
---|
437 | }
|
---|
438 | RT_EXPORT_SYMBOL(RTSemRWRequestRead);
|
---|
439 |
|
---|
440 |
|
---|
441 | RTDECL(int) RTSemRWRequestReadDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
|
---|
442 | {
|
---|
443 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
|
---|
444 | return rtSemRWRequestRead(hRWSem, cMillies, false, &SrcPos);
|
---|
445 | }
|
---|
446 | RT_EXPORT_SYMBOL(RTSemRWRequestReadDebug);
|
---|
447 |
|
---|
448 |
|
---|
449 | RTDECL(int) RTSemRWRequestReadNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
|
---|
450 | {
|
---|
451 | #ifndef RTSEMRW_STRICT
|
---|
452 | return rtSemRWRequestRead(hRWSem, cMillies, true, NULL);
|
---|
453 | #else
|
---|
454 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
|
---|
455 | return rtSemRWRequestRead(hRWSem, cMillies, true, &SrcPos);
|
---|
456 | #endif
|
---|
457 | }
|
---|
458 | RT_EXPORT_SYMBOL(RTSemRWRequestReadNoResume);
|
---|
459 |
|
---|
460 |
|
---|
461 | RTDECL(int) RTSemRWRequestReadNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
|
---|
462 | {
|
---|
463 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
|
---|
464 | return rtSemRWRequestRead(hRWSem, cMillies, true, &SrcPos);
|
---|
465 | }
|
---|
466 | RT_EXPORT_SYMBOL(RTSemRWRequestReadNoResumeDebug);
|
---|
467 |
|
---|
468 |
|
---|
469 |
|
---|
470 | RTDECL(int) RTSemRWReleaseRead(RTSEMRW hRWSem)
|
---|
471 | {
|
---|
472 | /*
|
---|
473 | * Validate handle.
|
---|
474 | */
|
---|
475 | RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
476 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
|
---|
477 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
|
---|
478 |
|
---|
479 | /*
|
---|
480 | * Check the direction and take action accordingly.
|
---|
481 | */
|
---|
482 | uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
483 | uint64_t u64OldState = u64State;
|
---|
484 | if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT))
|
---|
485 | {
|
---|
486 | #ifdef RTSEMRW_STRICT
|
---|
487 | int rc9 = RTLockValidatorRecSharedCheckAndRelease(&pThis->ValidatorRead, NIL_RTTHREAD);
|
---|
488 | if (RT_FAILURE(rc9))
|
---|
489 | return rc9;
|
---|
490 | #endif
|
---|
491 | for (;;)
|
---|
492 | {
|
---|
493 | uint64_t c = (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT;
|
---|
494 | AssertReturn(c > 0, VERR_NOT_OWNER);
|
---|
495 | c--;
|
---|
496 |
|
---|
497 | if ( c > 0
|
---|
498 | || (u64State & RTSEMRW_CNT_WD_MASK) == 0)
|
---|
499 | {
|
---|
500 | /* Don't change the direction. */
|
---|
501 | u64State &= ~RTSEMRW_CNT_RD_MASK;
|
---|
502 | u64State |= c << RTSEMRW_CNT_RD_SHIFT;
|
---|
503 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
|
---|
504 | break;
|
---|
505 | }
|
---|
506 | else
|
---|
507 | {
|
---|
508 | /* Reverse the direction and signal the reader threads. */
|
---|
509 | u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_DIR_MASK);
|
---|
510 | u64State |= RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT;
|
---|
511 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
|
---|
512 | {
|
---|
513 | int rc = RTSemEventSignal(pThis->hEvtWrite);
|
---|
514 | AssertRC(rc);
|
---|
515 | break;
|
---|
516 | }
|
---|
517 | }
|
---|
518 |
|
---|
519 | ASMNopPause();
|
---|
520 | u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
521 | u64OldState = u64State;
|
---|
522 | }
|
---|
523 | }
|
---|
524 | else
|
---|
525 | {
|
---|
526 | RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
|
---|
527 | RTNATIVETHREAD hNativeWriter;
|
---|
528 | ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
|
---|
529 | AssertReturn(hNativeSelf == hNativeWriter, VERR_NOT_OWNER);
|
---|
530 | AssertReturn(pThis->cWriterReads > 0, VERR_NOT_OWNER);
|
---|
531 | #ifdef RTSEMRW_STRICT
|
---|
532 | int rc = RTLockValidatorRecExclUnwindMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core);
|
---|
533 | if (RT_FAILURE(rc))
|
---|
534 | return rc;
|
---|
535 | #endif
|
---|
536 | ASMAtomicDecU32(&pThis->cWriterReads);
|
---|
537 | }
|
---|
538 |
|
---|
539 | return VINF_SUCCESS;
|
---|
540 | }
|
---|
541 | RT_EXPORT_SYMBOL(RTSemRWReleaseRead);
|
---|
542 |
|
---|
543 |
|
---|
544 | DECL_FORCE_INLINE(int) rtSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos)
|
---|
545 | {
|
---|
546 | /*
|
---|
547 | * Validate input.
|
---|
548 | */
|
---|
549 | RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
550 | if (pThis == NIL_RTSEMRW)
|
---|
551 | return VINF_SUCCESS;
|
---|
552 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
|
---|
553 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
|
---|
554 |
|
---|
555 | #ifdef RTSEMRW_STRICT
|
---|
556 | RTTHREAD hThreadSelf = NIL_RTTHREAD;
|
---|
557 | if (cMillies)
|
---|
558 | {
|
---|
559 | hThreadSelf = RTThreadSelfAutoAdopt();
|
---|
560 | int rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, cMillies);
|
---|
561 | if (RT_FAILURE(rc9))
|
---|
562 | return rc9;
|
---|
563 | }
|
---|
564 | #endif
|
---|
565 |
|
---|
566 | /*
|
---|
567 | * Check if we're already the owner and just recursing.
|
---|
568 | */
|
---|
569 | RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
|
---|
570 | RTNATIVETHREAD hNativeWriter;
|
---|
571 | ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
|
---|
572 | if (hNativeSelf == hNativeWriter)
|
---|
573 | {
|
---|
574 | Assert((ASMAtomicReadU64(&pThis->u64State) & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT));
|
---|
575 | #ifdef RTSEMRW_STRICT
|
---|
576 | int rc9 = RTLockValidatorRecExclRecursion(&pThis->ValidatorWrite, pSrcPos);
|
---|
577 | if (RT_FAILURE(rc9))
|
---|
578 | return rc9;
|
---|
579 | #endif
|
---|
580 | Assert(pThis->cWriteRecursions < UINT32_MAX / 2);
|
---|
581 | ASMAtomicIncU32(&pThis->cWriteRecursions);
|
---|
582 | return VINF_SUCCESS;
|
---|
583 | }
|
---|
584 |
|
---|
585 | /*
|
---|
586 | * Get cracking.
|
---|
587 | */
|
---|
588 | uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
589 | uint64_t u64OldState = u64State;
|
---|
590 |
|
---|
591 | for (;;)
|
---|
592 | {
|
---|
593 | if ( (u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT)
|
---|
594 | || (u64State & (RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK)) != 0)
|
---|
595 | {
|
---|
596 | /* It flows in the right direction, try follow it before it changes. */
|
---|
597 | uint64_t c = (u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT;
|
---|
598 | c++;
|
---|
599 | Assert(c < RTSEMRW_CNT_MASK / 2);
|
---|
600 | u64State &= ~RTSEMRW_CNT_WR_MASK;
|
---|
601 | u64State |= c << RTSEMRW_CNT_WR_SHIFT;
|
---|
602 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
|
---|
603 | break;
|
---|
604 | }
|
---|
605 | else if ((u64State & (RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK)) == 0)
|
---|
606 | {
|
---|
607 | /* Wrong direction, but we're alone here and can simply try switch the direction. */
|
---|
608 | u64State &= ~(RTSEMRW_CNT_RD_MASK | RTSEMRW_CNT_WR_MASK | RTSEMRW_DIR_MASK);
|
---|
609 | u64State |= (UINT64_C(1) << RTSEMRW_CNT_WR_SHIFT) | (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT);
|
---|
610 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
|
---|
611 | break;
|
---|
612 | }
|
---|
613 | else if (!cMillies)
|
---|
614 | /* Wrong direction and we're not supposed to wait, just return. */
|
---|
615 | return VERR_TIMEOUT;
|
---|
616 | else
|
---|
617 | {
|
---|
618 | /* Add ourselves to the write count and break out to do the wait. */
|
---|
619 | uint64_t c = (u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT;
|
---|
620 | c++;
|
---|
621 | Assert(c < RTSEMRW_CNT_MASK / 2);
|
---|
622 | u64State &= ~RTSEMRW_CNT_WR_MASK;
|
---|
623 | u64State |= c << RTSEMRW_CNT_WR_SHIFT;
|
---|
624 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
|
---|
625 | break;
|
---|
626 | }
|
---|
627 |
|
---|
628 | if (pThis->u32Magic != RTSEMRW_MAGIC)
|
---|
629 | return VERR_SEM_DESTROYED;
|
---|
630 |
|
---|
631 | ASMNopPause();
|
---|
632 | u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
633 | u64OldState = u64State;
|
---|
634 | }
|
---|
635 |
|
---|
636 | /*
|
---|
637 | * If we're in write mode now try grab the ownership. Play fair if there
|
---|
638 | * are threads already waiting.
|
---|
639 | */
|
---|
640 | bool fDone = (u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT)
|
---|
641 | && ( ((u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT) == 1
|
---|
642 | || cMillies == 0);
|
---|
643 | if (fDone)
|
---|
644 | ASMAtomicCmpXchgHandle(&pThis->hNativeWriter, hNativeSelf, NIL_RTNATIVETHREAD, fDone);
|
---|
645 | if (!fDone)
|
---|
646 | {
|
---|
647 | /*
|
---|
648 | * Wait for our turn.
|
---|
649 | */
|
---|
650 | for (uint32_t iLoop = 0; ; iLoop++)
|
---|
651 | {
|
---|
652 | int rc;
|
---|
653 | #ifdef RTSEMRW_STRICT
|
---|
654 | if (cMillies)
|
---|
655 | {
|
---|
656 | if (hThreadSelf == NIL_RTTHREAD)
|
---|
657 | hThreadSelf = RTThreadSelfAutoAdopt();
|
---|
658 | rc = RTLockValidatorRecExclCheckBlocking(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true,
|
---|
659 | cMillies, RTTHREADSTATE_RW_WRITE, false);
|
---|
660 | }
|
---|
661 | else
|
---|
662 | rc = VINF_SUCCESS;
|
---|
663 | if (RT_SUCCESS(rc))
|
---|
664 | #else
|
---|
665 | RTTHREAD hThreadSelf = RTThreadSelf();
|
---|
666 | RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_WRITE, false);
|
---|
667 | #endif
|
---|
668 | {
|
---|
669 | if (fInterruptible)
|
---|
670 | rc = RTSemEventWaitNoResume(pThis->hEvtWrite, cMillies);
|
---|
671 | else
|
---|
672 | rc = RTSemEventWait(pThis->hEvtWrite, cMillies);
|
---|
673 | RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_WRITE);
|
---|
674 | if (pThis->u32Magic != RTSEMRW_MAGIC)
|
---|
675 | return VERR_SEM_DESTROYED;
|
---|
676 | }
|
---|
677 | if (RT_FAILURE(rc))
|
---|
678 | {
|
---|
679 | /* Decrement the counts and return the error. */
|
---|
680 | for (;;)
|
---|
681 | {
|
---|
682 | u64OldState = u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
683 | uint64_t c = (u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT; Assert(c > 0);
|
---|
684 | c--;
|
---|
685 | u64State &= ~RTSEMRW_CNT_WR_MASK;
|
---|
686 | u64State |= c << RTSEMRW_CNT_WR_SHIFT;
|
---|
687 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
|
---|
688 | break;
|
---|
689 | }
|
---|
690 | return rc;
|
---|
691 | }
|
---|
692 |
|
---|
693 | u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
694 | if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT))
|
---|
695 | {
|
---|
696 | ASMAtomicCmpXchgHandle(&pThis->hNativeWriter, hNativeSelf, NIL_RTNATIVETHREAD, fDone);
|
---|
697 | if (fDone)
|
---|
698 | break;
|
---|
699 | }
|
---|
700 | AssertMsg(iLoop < 1000, ("%u\n", iLoop)); /* may loop a few times here... */
|
---|
701 | }
|
---|
702 | }
|
---|
703 |
|
---|
704 | /*
|
---|
705 | * Got it!
|
---|
706 | */
|
---|
707 | Assert((ASMAtomicReadU64(&pThis->u64State) & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT));
|
---|
708 | ASMAtomicWriteU32(&pThis->cWriteRecursions, 1);
|
---|
709 | Assert(pThis->cWriterReads == 0);
|
---|
710 | #ifdef RTSEMRW_STRICT
|
---|
711 | RTLockValidatorRecExclSetOwner(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true);
|
---|
712 | #endif
|
---|
713 |
|
---|
714 | return VINF_SUCCESS;
|
---|
715 | }
|
---|
716 |
|
---|
717 |
|
---|
718 | RTDECL(int) RTSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
|
---|
719 | {
|
---|
720 | #ifndef RTSEMRW_STRICT
|
---|
721 | return rtSemRWRequestWrite(hRWSem, cMillies, false, NULL);
|
---|
722 | #else
|
---|
723 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
|
---|
724 | return rtSemRWRequestWrite(hRWSem, cMillies, false, &SrcPos);
|
---|
725 | #endif
|
---|
726 | }
|
---|
727 | RT_EXPORT_SYMBOL(RTSemRWRequestWrite);
|
---|
728 |
|
---|
729 |
|
---|
730 | RTDECL(int) RTSemRWRequestWriteDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
|
---|
731 | {
|
---|
732 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
|
---|
733 | return rtSemRWRequestWrite(hRWSem, cMillies, false, &SrcPos);
|
---|
734 | }
|
---|
735 | RT_EXPORT_SYMBOL(RTSemRWRequestWriteDebug);
|
---|
736 |
|
---|
737 |
|
---|
738 | RTDECL(int) RTSemRWRequestWriteNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
|
---|
739 | {
|
---|
740 | #ifndef RTSEMRW_STRICT
|
---|
741 | return rtSemRWRequestWrite(hRWSem, cMillies, true, NULL);
|
---|
742 | #else
|
---|
743 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
|
---|
744 | return rtSemRWRequestWrite(hRWSem, cMillies, true, &SrcPos);
|
---|
745 | #endif
|
---|
746 | }
|
---|
747 | RT_EXPORT_SYMBOL(RTSemRWRequestWriteNoResume);
|
---|
748 |
|
---|
749 |
|
---|
750 | RTDECL(int) RTSemRWRequestWriteNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
|
---|
751 | {
|
---|
752 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
|
---|
753 | return rtSemRWRequestWrite(hRWSem, cMillies, true, &SrcPos);
|
---|
754 | }
|
---|
755 | RT_EXPORT_SYMBOL(RTSemRWRequestWriteNoResumeDebug);
|
---|
756 |
|
---|
757 |
|
---|
758 | RTDECL(int) RTSemRWReleaseWrite(RTSEMRW hRWSem)
|
---|
759 | {
|
---|
760 |
|
---|
761 | /*
|
---|
762 | * Validate handle.
|
---|
763 | */
|
---|
764 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
765 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
|
---|
766 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
|
---|
767 |
|
---|
768 | RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
|
---|
769 | RTNATIVETHREAD hNativeWriter;
|
---|
770 | ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
|
---|
771 | AssertReturn(hNativeSelf == hNativeWriter, VERR_NOT_OWNER);
|
---|
772 |
|
---|
773 | /*
|
---|
774 | * Unwind a recursion.
|
---|
775 | */
|
---|
776 | if (pThis->cWriteRecursions == 1)
|
---|
777 | {
|
---|
778 | AssertReturn(pThis->cWriterReads == 0, VERR_WRONG_ORDER); /* (must release all read recursions before the final write.) */
|
---|
779 | #ifdef RTSEMRW_STRICT
|
---|
780 | int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorWrite, true);
|
---|
781 | if (RT_FAILURE(rc9))
|
---|
782 | return rc9;
|
---|
783 | #endif
|
---|
784 | /*
|
---|
785 | * Update the state.
|
---|
786 | */
|
---|
787 | ASMAtomicWriteU32(&pThis->cWriteRecursions, 0);
|
---|
788 | ASMAtomicWriteHandle(&pThis->hNativeWriter, NIL_RTNATIVETHREAD);
|
---|
789 |
|
---|
790 | for (;;)
|
---|
791 | {
|
---|
792 | uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
793 | uint64_t u64OldState = u64State;
|
---|
794 |
|
---|
795 | uint64_t c = (u64State & RTSEMRW_CNT_WR_MASK) >> RTSEMRW_CNT_WR_SHIFT;
|
---|
796 | Assert(c > 0);
|
---|
797 | c--;
|
---|
798 |
|
---|
799 | if ( c > 0
|
---|
800 | || (u64State & RTSEMRW_CNT_RD_MASK) == 0)
|
---|
801 | {
|
---|
802 | /* Don't change the direction, wait up the next writer if any. */
|
---|
803 | u64State &= ~RTSEMRW_CNT_WR_MASK;
|
---|
804 | u64State |= c << RTSEMRW_CNT_WR_SHIFT;
|
---|
805 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
|
---|
806 | {
|
---|
807 | if (c > 0)
|
---|
808 | {
|
---|
809 | int rc = RTSemEventSignal(pThis->hEvtWrite);
|
---|
810 | AssertRC(rc);
|
---|
811 | }
|
---|
812 | break;
|
---|
813 | }
|
---|
814 | }
|
---|
815 | else
|
---|
816 | {
|
---|
817 | /* Reverse the direction and signal the reader threads. */
|
---|
818 | u64State &= ~(RTSEMRW_CNT_WR_MASK | RTSEMRW_DIR_MASK);
|
---|
819 | u64State |= RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT;
|
---|
820 | if (ASMAtomicCmpXchgU64(&pThis->u64State, u64State, u64OldState))
|
---|
821 | {
|
---|
822 | Assert(!pThis->fNeedReset);
|
---|
823 | ASMAtomicWriteBool(&pThis->fNeedReset, true);
|
---|
824 | int rc = RTSemEventMultiSignal(pThis->hEvtRead);
|
---|
825 | AssertRC(rc);
|
---|
826 | break;
|
---|
827 | }
|
---|
828 | }
|
---|
829 |
|
---|
830 | ASMNopPause();
|
---|
831 | if (pThis->u32Magic != RTSEMRW_MAGIC)
|
---|
832 | return VERR_SEM_DESTROYED;
|
---|
833 | }
|
---|
834 | }
|
---|
835 | else
|
---|
836 | {
|
---|
837 | Assert(pThis->cWriteRecursions != 0);
|
---|
838 | #ifdef RTSEMRW_STRICT
|
---|
839 | int rc9 = RTLockValidatorRecExclUnwind(&pThis->ValidatorWrite);
|
---|
840 | if (RT_FAILURE(rc9))
|
---|
841 | return rc9;
|
---|
842 | #endif
|
---|
843 | ASMAtomicDecU32(&pThis->cWriteRecursions);
|
---|
844 | }
|
---|
845 |
|
---|
846 | return VINF_SUCCESS;
|
---|
847 | }
|
---|
848 | RT_EXPORT_SYMBOL(RTSemRWReleaseWrite);
|
---|
849 |
|
---|
850 |
|
---|
851 | RTDECL(bool) RTSemRWIsWriteOwner(RTSEMRW hRWSem)
|
---|
852 | {
|
---|
853 | /*
|
---|
854 | * Validate handle.
|
---|
855 | */
|
---|
856 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
857 | AssertPtrReturn(pThis, false);
|
---|
858 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, false);
|
---|
859 |
|
---|
860 | /*
|
---|
861 | * Check ownership.
|
---|
862 | */
|
---|
863 | RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
|
---|
864 | RTNATIVETHREAD hNativeWriter;
|
---|
865 | ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hNativeWriter);
|
---|
866 | return hNativeWriter == hNativeSelf;
|
---|
867 | }
|
---|
868 | RT_EXPORT_SYMBOL(RTSemRWIsWriteOwner);
|
---|
869 |
|
---|
870 |
|
---|
871 | RTDECL(bool) RTSemRWIsReadOwner(RTSEMRW hRWSem, bool fWannaHear)
|
---|
872 | {
|
---|
873 | /*
|
---|
874 | * Validate handle.
|
---|
875 | */
|
---|
876 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
877 | AssertPtrReturn(pThis, false);
|
---|
878 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, false);
|
---|
879 |
|
---|
880 | /*
|
---|
881 | * Inspect the state.
|
---|
882 | */
|
---|
883 | uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
884 | if ((u64State & RTSEMRW_DIR_MASK) == (RTSEMRW_DIR_WRITE << RTSEMRW_DIR_SHIFT))
|
---|
885 | {
|
---|
886 | /*
|
---|
887 | * It's in write mode, so we can only be a reader if we're also the
|
---|
888 | * current writer.
|
---|
889 | */
|
---|
890 | RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
|
---|
891 | RTNATIVETHREAD hWriter;
|
---|
892 | ASMAtomicUoReadHandle(&pThis->hNativeWriter, &hWriter);
|
---|
893 | return hWriter == hNativeSelf;
|
---|
894 | }
|
---|
895 |
|
---|
896 | /*
|
---|
897 | * Read mode. If there are no current readers, then we cannot be a reader.
|
---|
898 | */
|
---|
899 | if (!(u64State & RTSEMRW_CNT_RD_MASK))
|
---|
900 | return false;
|
---|
901 |
|
---|
902 | #ifdef RTSEMRW_STRICT
|
---|
903 | /*
|
---|
904 | * Ask the lock validator.
|
---|
905 | */
|
---|
906 | return RTLockValidatorRecSharedIsOwner(&pThis->ValidatorRead, NIL_RTTHREAD);
|
---|
907 | #else
|
---|
908 | /*
|
---|
909 | * Ok, we don't know, just tell the caller what he want to hear.
|
---|
910 | */
|
---|
911 | return fWannaHear;
|
---|
912 | #endif
|
---|
913 | }
|
---|
914 | RT_EXPORT_SYMBOL(RTSemRWIsReadOwner);
|
---|
915 |
|
---|
916 |
|
---|
917 | RTDECL(uint32_t) RTSemRWGetWriteRecursion(RTSEMRW hRWSem)
|
---|
918 | {
|
---|
919 | /*
|
---|
920 | * Validate handle.
|
---|
921 | */
|
---|
922 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
923 | AssertPtrReturn(pThis, 0);
|
---|
924 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, 0);
|
---|
925 |
|
---|
926 | /*
|
---|
927 | * Return the requested data.
|
---|
928 | */
|
---|
929 | return pThis->cWriteRecursions;
|
---|
930 | }
|
---|
931 | RT_EXPORT_SYMBOL(RTSemRWGetWriteRecursion);
|
---|
932 |
|
---|
933 |
|
---|
934 | RTDECL(uint32_t) RTSemRWGetWriterReadRecursion(RTSEMRW hRWSem)
|
---|
935 | {
|
---|
936 | /*
|
---|
937 | * Validate handle.
|
---|
938 | */
|
---|
939 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
940 | AssertPtrReturn(pThis, 0);
|
---|
941 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, 0);
|
---|
942 |
|
---|
943 | /*
|
---|
944 | * Return the requested data.
|
---|
945 | */
|
---|
946 | return pThis->cWriterReads;
|
---|
947 | }
|
---|
948 | RT_EXPORT_SYMBOL(RTSemRWGetWriterReadRecursion);
|
---|
949 |
|
---|
950 |
|
---|
951 | RTDECL(uint32_t) RTSemRWGetReadCount(RTSEMRW hRWSem)
|
---|
952 | {
|
---|
953 | /*
|
---|
954 | * Validate input.
|
---|
955 | */
|
---|
956 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
957 | AssertPtrReturn(pThis, 0);
|
---|
958 | AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
|
---|
959 | ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
|
---|
960 | 0);
|
---|
961 |
|
---|
962 | /*
|
---|
963 | * Return the requested data.
|
---|
964 | */
|
---|
965 | uint64_t u64State = ASMAtomicReadU64(&pThis->u64State);
|
---|
966 | if ((u64State & RTSEMRW_DIR_MASK) != (RTSEMRW_DIR_READ << RTSEMRW_DIR_SHIFT))
|
---|
967 | return 0;
|
---|
968 | return (u64State & RTSEMRW_CNT_RD_MASK) >> RTSEMRW_CNT_RD_SHIFT;
|
---|
969 | }
|
---|
970 | RT_EXPORT_SYMBOL(RTSemRWGetReadCount);
|
---|
971 |
|
---|