1 | /* $Id: semrw-generic.cpp 62592 2016-07-27 13:24:48Z vboxsync $ */
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2 | /** @file
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3 | * IPRT - Read-Write Semaphore, Generic.
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4 | *
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5 | * This is a generic implementation for OSes which don't have
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6 | * native RW semaphores.
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7 | */
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8 |
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9 | /*
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10 | * Copyright (C) 2006-2016 Oracle Corporation
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11 | *
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12 | * This file is part of VirtualBox Open Source Edition (OSE), as
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13 | * available from http://www.virtualbox.org. This file is free software;
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14 | * you can redistribute it and/or modify it under the terms of the GNU
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15 | * General Public License (GPL) as published by the Free Software
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16 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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17 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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18 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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19 | *
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20 | * The contents of this file may alternatively be used under the terms
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21 | * of the Common Development and Distribution License Version 1.0
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22 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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23 | * VirtualBox OSE distribution, in which case the provisions of the
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24 | * CDDL are applicable instead of those of the GPL.
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25 | *
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26 | * You may elect to license modified versions of this file under the
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27 | * terms and conditions of either the GPL or the CDDL or both.
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28 | */
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29 |
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30 |
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31 | /*********************************************************************************************************************************
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32 | * Header Files *
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33 | *********************************************************************************************************************************/
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34 | #define RTSEMRW_WITHOUT_REMAPPING
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35 | #include <iprt/semaphore.h>
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36 | #include "internal/iprt.h"
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37 |
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38 | #include <iprt/asm.h>
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39 | #include <iprt/assert.h>
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40 | #include <iprt/critsect.h>
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41 | #include <iprt/err.h>
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42 | #include <iprt/lockvalidator.h>
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43 | #include <iprt/mem.h>
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44 | #include <iprt/time.h>
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45 | #include <iprt/thread.h>
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46 |
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47 | #include "internal/magics.h"
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48 | #include "internal/strict.h"
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49 |
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50 |
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51 | /*********************************************************************************************************************************
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52 | * Structures and Typedefs *
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53 | *********************************************************************************************************************************/
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54 |
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55 | /** Internal representation of a Read-Write semaphore for the
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56 | * Generic implementation. */
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57 | struct RTSEMRWINTERNAL
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58 | {
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59 | /** The usual magic. (RTSEMRW_MAGIC) */
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60 | uint32_t u32Magic;
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61 | /* Alignment padding. */
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62 | uint32_t u32Padding;
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63 | /** This critical section serializes the access to and updating of the structure members. */
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64 | RTCRITSECT CritSect;
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65 | /** The current number of reads. (pure read recursion counts too) */
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66 | uint32_t cReads;
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67 | /** The current number of writes. (recursion counts too) */
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68 | uint32_t cWrites;
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69 | /** Number of read recursions by the writer. */
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70 | uint32_t cWriterReads;
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71 | /** Number of writers waiting. */
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72 | uint32_t cWritesWaiting;
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73 | /** The write owner of the lock. */
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74 | RTNATIVETHREAD hWriter;
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75 | /** The handle of the event object on which the waiting readers block. (manual reset). */
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76 | RTSEMEVENTMULTI ReadEvent;
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77 | /** The handle of the event object on which the waiting writers block. (automatic reset). */
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78 | RTSEMEVENT WriteEvent;
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79 | /** Need to reset ReadEvent. */
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80 | bool fNeedResetReadEvent;
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81 | #ifdef RTSEMRW_STRICT
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82 | /** The validator record for the writer. */
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83 | RTLOCKVALRECEXCL ValidatorWrite;
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84 | /** The validator record for the readers. */
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85 | RTLOCKVALRECSHRD ValidatorRead;
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86 | #endif
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87 | };
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88 |
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89 |
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90 |
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91 | RTDECL(int) RTSemRWCreate(PRTSEMRW phRWSem)
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92 | {
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93 | return RTSemRWCreateEx(phRWSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, "RTSemRW");
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94 | }
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95 | RT_EXPORT_SYMBOL(RTSemRWCreate);
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96 |
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97 |
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98 | RTDECL(int) RTSemRWCreateEx(PRTSEMRW phRWSem, uint32_t fFlags,
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99 | RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...)
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100 | {
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101 | AssertReturn(!(fFlags & ~RTSEMRW_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
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102 |
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103 | /*
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104 | * Allocate memory.
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105 | */
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106 | int rc;
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107 | struct RTSEMRWINTERNAL *pThis = (struct RTSEMRWINTERNAL *)RTMemAlloc(sizeof(struct RTSEMRWINTERNAL));
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108 | if (pThis)
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109 | {
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110 | /*
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111 | * Create the semaphores.
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112 | */
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113 | rc = RTSemEventCreateEx(&pThis->WriteEvent, RTSEMEVENT_FLAGS_NO_LOCK_VAL, NIL_RTLOCKVALCLASS, NULL);
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114 | if (RT_SUCCESS(rc))
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115 | {
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116 | rc = RTSemEventMultiCreateEx(&pThis->ReadEvent, RTSEMEVENT_FLAGS_NO_LOCK_VAL, NIL_RTLOCKVALCLASS, NULL);
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117 | if (RT_SUCCESS(rc))
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118 | {
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119 | rc = RTCritSectInitEx(&pThis->CritSect, RTCRITSECT_FLAGS_NO_LOCK_VAL,
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120 | NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, NULL);
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121 | if (RT_SUCCESS(rc))
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122 | {
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123 | /*
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124 | * Signal the read semaphore and initialize other variables.
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125 | */
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126 | rc = RTSemEventMultiSignal(pThis->ReadEvent);
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127 | if (RT_SUCCESS(rc))
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128 | {
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129 | pThis->u32Padding = UINT32_C(0xa5a55a5a);
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130 | pThis->cReads = 0;
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131 | pThis->cWrites = 0;
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132 | pThis->cWriterReads = 0;
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133 | pThis->cWritesWaiting = 0;
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134 | pThis->hWriter = NIL_RTNATIVETHREAD;
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135 | pThis->fNeedResetReadEvent = true;
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136 | pThis->u32Magic = RTSEMRW_MAGIC;
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137 | #ifdef RTSEMRW_STRICT
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138 | bool const fLVEnabled = !(fFlags & RTSEMRW_FLAGS_NO_LOCK_VAL);
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139 | if (!pszNameFmt)
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140 | {
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141 | static uint32_t volatile s_iSemRWAnon = 0;
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142 | uint32_t i = ASMAtomicIncU32(&s_iSemRWAnon) - 1;
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143 | RTLockValidatorRecExclInit(&pThis->ValidatorWrite, hClass, uSubClass, pThis,
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144 | fLVEnabled, "RTSemRW-%u", i);
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145 | RTLockValidatorRecSharedInit(&pThis->ValidatorRead, hClass, uSubClass, pThis,
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146 | false /*fSignaller*/, fLVEnabled, "RTSemRW-%u", i);
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147 | }
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148 | else
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149 | {
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150 | va_list va;
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151 | va_start(va, pszNameFmt);
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152 | RTLockValidatorRecExclInitV(&pThis->ValidatorWrite, hClass, uSubClass, pThis,
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153 | fLVEnabled, pszNameFmt, va);
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154 | va_end(va);
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155 | va_start(va, pszNameFmt);
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156 | RTLockValidatorRecSharedInitV(&pThis->ValidatorRead, hClass, uSubClass, pThis,
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157 | false /*fSignaller*/, fLVEnabled, pszNameFmt, va);
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158 | va_end(va);
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159 | }
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160 | RTLockValidatorRecMakeSiblings(&pThis->ValidatorWrite.Core, &pThis->ValidatorRead.Core);
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161 | #else
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162 | RT_NOREF_PV(hClass); RT_NOREF_PV(uSubClass); RT_NOREF_PV(pszNameFmt);
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163 | #endif
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164 | *phRWSem = pThis;
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165 | return VINF_SUCCESS;
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166 | }
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167 | RTCritSectDelete(&pThis->CritSect);
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168 | }
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169 | RTSemEventMultiDestroy(pThis->ReadEvent);
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170 | }
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171 | RTSemEventDestroy(pThis->WriteEvent);
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172 | }
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173 | RTMemFree(pThis);
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174 | }
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175 | else
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176 | rc = VERR_NO_MEMORY;
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177 |
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178 | return rc;
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179 | }
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180 | RT_EXPORT_SYMBOL(RTSemRWCreate);
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181 |
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182 |
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183 | RTDECL(int) RTSemRWDestroy(RTSEMRW hRWSem)
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184 | {
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185 | struct RTSEMRWINTERNAL *pThis = hRWSem;
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186 |
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187 | /*
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188 | * Validate handle.
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189 | */
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190 | if (pThis == NIL_RTSEMRW)
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191 | return VINF_SUCCESS;
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192 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
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193 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
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194 |
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195 | /*
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196 | * Check if busy.
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197 | */
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198 | int rc = RTCritSectTryEnter(&pThis->CritSect);
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199 | if (RT_SUCCESS(rc))
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200 | {
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201 | if (!pThis->cReads && !pThis->cWrites)
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202 | {
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203 | /*
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204 | * Make it invalid and unusable.
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205 | */
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206 | ASMAtomicWriteU32(&pThis->u32Magic, ~RTSEMRW_MAGIC);
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207 | pThis->cReads = UINT32_MAX;
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208 |
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209 | /*
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210 | * Do actual cleanup. None of these can now fail.
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211 | */
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212 | rc = RTSemEventMultiDestroy(pThis->ReadEvent);
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213 | AssertMsgRC(rc, ("RTSemEventMultiDestroy failed! rc=%Rrc\n", rc));
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214 | pThis->ReadEvent = NIL_RTSEMEVENTMULTI;
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215 |
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216 | rc = RTSemEventDestroy(pThis->WriteEvent);
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217 | AssertMsgRC(rc, ("RTSemEventDestroy failed! rc=%Rrc\n", rc));
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218 | pThis->WriteEvent = NIL_RTSEMEVENT;
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219 |
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220 | RTCritSectLeave(&pThis->CritSect);
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221 | rc = RTCritSectDelete(&pThis->CritSect);
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222 | AssertMsgRC(rc, ("RTCritSectDelete failed! rc=%Rrc\n", rc));
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223 |
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224 | #ifdef RTSEMRW_STRICT
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225 | RTLockValidatorRecSharedDelete(&pThis->ValidatorRead);
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226 | RTLockValidatorRecExclDelete(&pThis->ValidatorWrite);
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227 | #endif
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228 | RTMemFree(pThis);
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229 | rc = VINF_SUCCESS;
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230 | }
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231 | else
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232 | {
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233 | rc = VERR_SEM_BUSY;
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234 | RTCritSectLeave(&pThis->CritSect);
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235 | }
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236 | }
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237 | else
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238 | {
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239 | AssertMsgRC(rc, ("RTCritSectTryEnter failed! rc=%Rrc\n", rc));
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240 | rc = VERR_SEM_BUSY;
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241 | }
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242 |
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243 | return rc;
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244 | }
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245 | RT_EXPORT_SYMBOL(RTSemRWDestroy);
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246 |
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247 |
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248 | RTDECL(uint32_t) RTSemRWSetSubClass(RTSEMRW hRWSem, uint32_t uSubClass)
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249 | {
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250 | #ifdef RTSEMRW_STRICT
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251 | /*
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252 | * Validate handle.
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253 | */
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254 | struct RTSEMRWINTERNAL *pThis = hRWSem;
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255 | AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID);
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256 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID);
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257 |
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258 | RTLockValidatorRecSharedSetSubClass(&pThis->ValidatorRead, uSubClass);
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259 | return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorWrite, uSubClass);
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260 | #else
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261 | RT_NOREF_PV(hRWSem); RT_NOREF_PV(uSubClass);
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262 | return RTLOCKVAL_SUB_CLASS_INVALID;
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263 | #endif
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264 | }
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265 | RT_EXPORT_SYMBOL(RTSemRWSetSubClass);
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266 |
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267 |
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268 | DECL_FORCE_INLINE(int) rtSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos)
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269 | {
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270 | /*
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271 | * Validate handle.
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272 | */
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273 | struct RTSEMRWINTERNAL *pThis = hRWSem;
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274 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
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275 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
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276 |
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277 | RTMSINTERVAL cMilliesInitial = cMillies;
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278 | uint64_t tsStart = 0;
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279 | if (cMillies != RT_INDEFINITE_WAIT && cMillies != 0)
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280 | tsStart = RTTimeNanoTS();
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281 |
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282 | #ifdef RTSEMRW_STRICT
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283 | RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
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284 | if (cMillies > 0)
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285 | {
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286 | int rc9;
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287 | if (pThis->hWriter != NIL_RTTHREAD && pThis->hWriter == RTThreadNativeSelf())
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288 | rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, cMillies);
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289 | else
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290 | rc9 = RTLockValidatorRecSharedCheckOrder(&pThis->ValidatorRead, hThreadSelf, pSrcPos, cMillies);
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291 | if (RT_FAILURE(rc9))
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292 | return rc9;
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293 | }
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294 | #endif
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295 |
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296 | /*
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297 | * Take critsect.
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298 | */
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299 | int rc = RTCritSectEnter(&pThis->CritSect);
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300 | if (RT_FAILURE(rc))
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301 | {
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302 | AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
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303 | return rc;
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304 | }
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305 |
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306 | /*
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307 | * Check if the state of affairs allows read access.
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308 | * Do not block further readers if there is a writer waiting, as
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309 | * that will break/deadlock reader recursion.
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310 | */
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311 | if ( pThis->hWriter == NIL_RTNATIVETHREAD
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312 | #if 0
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313 | && ( !pThis->cWritesWaiting
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314 | || pThis->cReads)
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315 | #endif
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316 | )
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317 | {
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318 | pThis->cReads++;
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319 | Assert(pThis->cReads > 0);
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320 | #ifdef RTSEMRW_STRICT
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321 | RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
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322 | #endif
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323 |
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324 | RTCritSectLeave(&pThis->CritSect);
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325 | return VINF_SUCCESS;
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326 | }
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327 |
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328 | RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner;
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329 | if (pThis->hWriter == hNativeSelf)
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330 | {
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331 | #ifdef RTSEMRW_STRICT
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332 | int rc9 = RTLockValidatorRecExclRecursionMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core, pSrcPos);
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333 | if (RT_FAILURE(rc9))
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334 | {
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335 | RTCritSectLeave(&pThis->CritSect);
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336 | return rc9;
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337 | }
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338 | #endif
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339 |
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340 | pThis->cWriterReads++;
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341 | Assert(pThis->cWriterReads > 0);
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342 |
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343 | RTCritSectLeave(&pThis->CritSect);
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344 | return VINF_SUCCESS;
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345 | }
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346 |
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347 | RTCritSectLeave(&pThis->CritSect);
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348 |
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349 | /*
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350 | * Wait till it's ready for reading.
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351 | */
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352 | if (cMillies == 0)
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353 | return VERR_TIMEOUT;
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354 |
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355 | #ifndef RTSEMRW_STRICT
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356 | RTTHREAD hThreadSelf = RTThreadSelf();
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357 | #endif
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358 | for (;;)
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359 | {
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360 | if (cMillies != RT_INDEFINITE_WAIT)
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361 | {
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362 | int64_t tsDelta = RTTimeNanoTS() - tsStart;
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363 | if (tsDelta >= 1000000)
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364 | {
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365 | tsDelta /= 1000000;
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366 | if ((uint64_t)tsDelta < cMilliesInitial)
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367 | cMilliesInitial = (RTMSINTERVAL)tsDelta;
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368 | else
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369 | cMilliesInitial = 1;
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370 | }
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371 | }
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372 | #ifdef RTSEMRW_STRICT
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373 | rc = RTLockValidatorRecSharedCheckBlocking(&pThis->ValidatorRead, hThreadSelf, pSrcPos, true,
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374 | cMillies, RTTHREADSTATE_RW_READ, false);
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375 | if (RT_FAILURE(rc))
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376 | break;
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377 | #else
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378 | RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_READ, false);
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379 | RT_NOREF_PV(pSrcPos);
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380 | #endif
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381 | int rcWait;
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382 | if (fInterruptible)
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383 | rcWait = rc = RTSemEventMultiWaitNoResume(pThis->ReadEvent, cMillies);
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384 | else
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385 | rcWait = rc = RTSemEventMultiWait(pThis->ReadEvent, cMillies);
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386 | RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ);
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387 | if (RT_FAILURE(rc) && rc != VERR_TIMEOUT) /* handle timeout below */
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388 | {
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389 | AssertMsgRC(rc, ("RTSemEventMultiWait failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
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390 | break;
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391 | }
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392 |
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393 | if (pThis->u32Magic != RTSEMRW_MAGIC)
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394 | {
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395 | rc = VERR_SEM_DESTROYED;
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396 | break;
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397 | }
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398 |
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399 | /*
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400 | * Re-take critsect and repeat the check we did before the loop.
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401 | */
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402 | rc = RTCritSectEnter(&pThis->CritSect);
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403 | if (RT_FAILURE(rc))
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404 | {
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405 | AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
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406 | break;
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407 | }
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408 |
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409 | if ( pThis->hWriter == NIL_RTNATIVETHREAD
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410 | #if 0
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411 | && ( !pThis->cWritesWaiting
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412 | || pThis->cReads)
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413 | #endif
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414 | )
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415 | {
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416 | pThis->cReads++;
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417 | Assert(pThis->cReads > 0);
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418 | #ifdef RTSEMRW_STRICT
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419 | RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
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420 | #endif
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421 |
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422 | RTCritSectLeave(&pThis->CritSect);
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423 | return VINF_SUCCESS;
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424 | }
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425 |
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426 | RTCritSectLeave(&pThis->CritSect);
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427 |
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428 | /*
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429 | * Quit if the wait already timed out.
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430 | */
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431 | if (rcWait == VERR_TIMEOUT)
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432 | {
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433 | rc = VERR_TIMEOUT;
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434 | break;
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435 | }
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436 | }
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437 |
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438 | /* failed */
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439 | return rc;
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440 | }
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441 |
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442 |
|
---|
443 | RTDECL(int) RTSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
|
---|
444 | {
|
---|
445 | #ifndef RTSEMRW_STRICT
|
---|
446 | return rtSemRWRequestRead(hRWSem, cMillies, false, NULL);
|
---|
447 | #else
|
---|
448 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
|
---|
449 | return rtSemRWRequestRead(hRWSem, cMillies, false, &SrcPos);
|
---|
450 | #endif
|
---|
451 | }
|
---|
452 | RT_EXPORT_SYMBOL(RTSemRWRequestRead);
|
---|
453 |
|
---|
454 |
|
---|
455 | RTDECL(int) RTSemRWRequestReadDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
|
---|
456 | {
|
---|
457 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
|
---|
458 | return rtSemRWRequestRead(hRWSem, cMillies, false, &SrcPos);
|
---|
459 | }
|
---|
460 | RT_EXPORT_SYMBOL(RTSemRWRequestReadDebug);
|
---|
461 |
|
---|
462 |
|
---|
463 | RTDECL(int) RTSemRWRequestReadNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
|
---|
464 | {
|
---|
465 | #ifndef RTSEMRW_STRICT
|
---|
466 | return rtSemRWRequestRead(hRWSem, cMillies, true, NULL);
|
---|
467 | #else
|
---|
468 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
|
---|
469 | return rtSemRWRequestRead(hRWSem, cMillies, true, &SrcPos);
|
---|
470 | #endif
|
---|
471 | }
|
---|
472 | RT_EXPORT_SYMBOL(RTSemRWRequestReadNoResume);
|
---|
473 |
|
---|
474 |
|
---|
475 | RTDECL(int) RTSemRWRequestReadNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
|
---|
476 | {
|
---|
477 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
|
---|
478 | return rtSemRWRequestRead(hRWSem, cMillies, true, &SrcPos);
|
---|
479 | }
|
---|
480 | RT_EXPORT_SYMBOL(RTSemRWRequestReadNoResumeDebug);
|
---|
481 |
|
---|
482 |
|
---|
483 | RTDECL(int) RTSemRWReleaseRead(RTSEMRW hRWSem)
|
---|
484 | {
|
---|
485 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
486 |
|
---|
487 | /*
|
---|
488 | * Validate handle.
|
---|
489 | */
|
---|
490 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
|
---|
491 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
|
---|
492 |
|
---|
493 | /*
|
---|
494 | * Take critsect.
|
---|
495 | */
|
---|
496 | int rc = RTCritSectEnter(&pThis->CritSect);
|
---|
497 | if (RT_SUCCESS(rc))
|
---|
498 | {
|
---|
499 | if (pThis->hWriter == NIL_RTNATIVETHREAD)
|
---|
500 | {
|
---|
501 | #ifdef RTSEMRW_STRICT
|
---|
502 | rc = RTLockValidatorRecSharedCheckAndRelease(&pThis->ValidatorRead, NIL_RTTHREAD);
|
---|
503 | if (RT_SUCCESS(rc))
|
---|
504 | #endif
|
---|
505 | {
|
---|
506 | if (RT_LIKELY(pThis->cReads > 0))
|
---|
507 | {
|
---|
508 | pThis->cReads--;
|
---|
509 |
|
---|
510 | /* Kick off a writer if appropriate. */
|
---|
511 | if ( pThis->cWritesWaiting > 0
|
---|
512 | && !pThis->cReads)
|
---|
513 | {
|
---|
514 | rc = RTSemEventSignal(pThis->WriteEvent);
|
---|
515 | AssertMsgRC(rc, ("Failed to signal writers on rwsem %p, rc=%Rrc\n", hRWSem, rc));
|
---|
516 | }
|
---|
517 | }
|
---|
518 | else
|
---|
519 | {
|
---|
520 | AssertFailed();
|
---|
521 | rc = VERR_NOT_OWNER;
|
---|
522 | }
|
---|
523 | }
|
---|
524 | }
|
---|
525 | else
|
---|
526 | {
|
---|
527 | RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner;
|
---|
528 | if (pThis->hWriter == hNativeSelf)
|
---|
529 | {
|
---|
530 | if (pThis->cWriterReads > 0)
|
---|
531 | {
|
---|
532 | #ifdef RTSEMRW_STRICT
|
---|
533 | rc = RTLockValidatorRecExclUnwindMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core);
|
---|
534 | if (RT_SUCCESS(rc))
|
---|
535 | #endif
|
---|
536 | {
|
---|
537 | pThis->cWriterReads--;
|
---|
538 | }
|
---|
539 | }
|
---|
540 | else
|
---|
541 | {
|
---|
542 | AssertFailed();
|
---|
543 | rc = VERR_NOT_OWNER;
|
---|
544 | }
|
---|
545 | }
|
---|
546 | else
|
---|
547 | {
|
---|
548 | AssertFailed();
|
---|
549 | rc = VERR_NOT_OWNER;
|
---|
550 | }
|
---|
551 | }
|
---|
552 |
|
---|
553 | RTCritSectLeave(&pThis->CritSect);
|
---|
554 | }
|
---|
555 | else
|
---|
556 | AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
|
---|
557 |
|
---|
558 | return rc;
|
---|
559 | }
|
---|
560 | RT_EXPORT_SYMBOL(RTSemRWReleaseRead);
|
---|
561 |
|
---|
562 |
|
---|
563 | DECL_FORCE_INLINE(int) rtSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos)
|
---|
564 | {
|
---|
565 | /*
|
---|
566 | * Validate handle.
|
---|
567 | */
|
---|
568 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
569 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
|
---|
570 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
|
---|
571 |
|
---|
572 | RTMSINTERVAL cMilliesInitial = cMillies;
|
---|
573 | uint64_t tsStart = 0;
|
---|
574 | if (cMillies != RT_INDEFINITE_WAIT && cMillies != 0)
|
---|
575 | tsStart = RTTimeNanoTS();
|
---|
576 |
|
---|
577 | #ifdef RTSEMRW_STRICT
|
---|
578 | RTTHREAD hThreadSelf = NIL_RTTHREAD;
|
---|
579 | if (cMillies)
|
---|
580 | {
|
---|
581 | hThreadSelf = RTThreadSelfAutoAdopt();
|
---|
582 | int rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, cMillies);
|
---|
583 | if (RT_FAILURE(rc9))
|
---|
584 | return rc9;
|
---|
585 | }
|
---|
586 | #endif
|
---|
587 |
|
---|
588 | /*
|
---|
589 | * Take critsect.
|
---|
590 | */
|
---|
591 | int rc = RTCritSectEnter(&pThis->CritSect);
|
---|
592 | if (RT_FAILURE(rc))
|
---|
593 | {
|
---|
594 | AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
|
---|
595 | return rc;
|
---|
596 | }
|
---|
597 |
|
---|
598 | /*
|
---|
599 | * Check if the state of affairs allows write access.
|
---|
600 | */
|
---|
601 | RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner;
|
---|
602 | if ( !pThis->cReads
|
---|
603 | && ( ( !pThis->cWrites
|
---|
604 | && ( !pThis->cWritesWaiting /* play fair if we can wait */
|
---|
605 | || !cMillies)
|
---|
606 | )
|
---|
607 | || pThis->hWriter == hNativeSelf
|
---|
608 | )
|
---|
609 | )
|
---|
610 | {
|
---|
611 | /*
|
---|
612 | * Reset the reader event semaphore if necessary.
|
---|
613 | */
|
---|
614 | if (pThis->fNeedResetReadEvent)
|
---|
615 | {
|
---|
616 | pThis->fNeedResetReadEvent = false;
|
---|
617 | rc = RTSemEventMultiReset(pThis->ReadEvent);
|
---|
618 | AssertMsgRC(rc, ("Failed to reset readers, rwsem %p, rc=%Rrc.\n", hRWSem, rc));
|
---|
619 | }
|
---|
620 |
|
---|
621 | pThis->cWrites++;
|
---|
622 | pThis->hWriter = hNativeSelf;
|
---|
623 | #ifdef RTSEMRW_STRICT
|
---|
624 | RTLockValidatorRecExclSetOwner(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, pThis->cWrites == 1);
|
---|
625 | #endif
|
---|
626 | RTCritSectLeave(&pThis->CritSect);
|
---|
627 | return VINF_SUCCESS;
|
---|
628 | }
|
---|
629 |
|
---|
630 | /*
|
---|
631 | * Signal writer presence.
|
---|
632 | */
|
---|
633 | if (cMillies != 0)
|
---|
634 | pThis->cWritesWaiting++;
|
---|
635 |
|
---|
636 | RTCritSectLeave(&pThis->CritSect);
|
---|
637 |
|
---|
638 | /*
|
---|
639 | * Wait till it's ready for writing.
|
---|
640 | */
|
---|
641 | if (cMillies == 0)
|
---|
642 | return VERR_TIMEOUT;
|
---|
643 |
|
---|
644 | #ifndef RTSEMRW_STRICT
|
---|
645 | RTTHREAD hThreadSelf = RTThreadSelf();
|
---|
646 | #endif
|
---|
647 | for (;;)
|
---|
648 | {
|
---|
649 | if (cMillies != RT_INDEFINITE_WAIT)
|
---|
650 | {
|
---|
651 | int64_t tsDelta = RTTimeNanoTS() - tsStart;
|
---|
652 | if (tsDelta >= 1000000)
|
---|
653 | {
|
---|
654 | tsDelta /= 1000000;
|
---|
655 | if ((uint64_t)tsDelta < cMilliesInitial)
|
---|
656 | cMilliesInitial = (RTMSINTERVAL)tsDelta;
|
---|
657 | else
|
---|
658 | cMilliesInitial = 1;
|
---|
659 | }
|
---|
660 | }
|
---|
661 |
|
---|
662 | #ifdef RTSEMRW_STRICT
|
---|
663 | rc = RTLockValidatorRecExclCheckBlocking(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true,
|
---|
664 | cMillies, RTTHREADSTATE_RW_WRITE, false);
|
---|
665 | if (RT_FAILURE(rc))
|
---|
666 | break;
|
---|
667 | #else
|
---|
668 | RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_WRITE, false);
|
---|
669 | RT_NOREF_PV(pSrcPos);
|
---|
670 | #endif
|
---|
671 | int rcWait;
|
---|
672 | if (fInterruptible)
|
---|
673 | rcWait = rc = RTSemEventWaitNoResume(pThis->WriteEvent, cMillies);
|
---|
674 | else
|
---|
675 | rcWait = rc = RTSemEventWait(pThis->WriteEvent, cMillies);
|
---|
676 | RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_WRITE);
|
---|
677 | if (RT_UNLIKELY(RT_FAILURE_NP(rc) && rc != VERR_TIMEOUT)) /* timeouts are handled below */
|
---|
678 | {
|
---|
679 | AssertMsgRC(rc, ("RTSemEventWait failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
|
---|
680 | break;
|
---|
681 | }
|
---|
682 |
|
---|
683 | if (RT_UNLIKELY(pThis->u32Magic != RTSEMRW_MAGIC))
|
---|
684 | {
|
---|
685 | rc = VERR_SEM_DESTROYED;
|
---|
686 | break;
|
---|
687 | }
|
---|
688 |
|
---|
689 | /*
|
---|
690 | * Re-take critsect and repeat the check we did prior to this loop.
|
---|
691 | */
|
---|
692 | rc = RTCritSectEnter(&pThis->CritSect);
|
---|
693 | if (RT_FAILURE(rc))
|
---|
694 | {
|
---|
695 | AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
|
---|
696 | break;
|
---|
697 | }
|
---|
698 |
|
---|
699 | if (!pThis->cReads && (!pThis->cWrites || pThis->hWriter == hNativeSelf))
|
---|
700 | {
|
---|
701 | /*
|
---|
702 | * Reset the reader event semaphore if necessary.
|
---|
703 | */
|
---|
704 | if (pThis->fNeedResetReadEvent)
|
---|
705 | {
|
---|
706 | pThis->fNeedResetReadEvent = false;
|
---|
707 | rc = RTSemEventMultiReset(pThis->ReadEvent);
|
---|
708 | AssertMsgRC(rc, ("Failed to reset readers, rwsem %p, rc=%Rrc.\n", hRWSem, rc));
|
---|
709 | }
|
---|
710 |
|
---|
711 | pThis->cWrites++;
|
---|
712 | pThis->hWriter = hNativeSelf;
|
---|
713 | pThis->cWritesWaiting--;
|
---|
714 | #ifdef RTSEMRW_STRICT
|
---|
715 | RTLockValidatorRecExclSetOwner(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true);
|
---|
716 | #endif
|
---|
717 |
|
---|
718 | RTCritSectLeave(&pThis->CritSect);
|
---|
719 | return VINF_SUCCESS;
|
---|
720 | }
|
---|
721 |
|
---|
722 | RTCritSectLeave(&pThis->CritSect);
|
---|
723 |
|
---|
724 | /*
|
---|
725 | * Quit if the wait already timed out.
|
---|
726 | */
|
---|
727 | if (rcWait == VERR_TIMEOUT)
|
---|
728 | {
|
---|
729 | rc = VERR_TIMEOUT;
|
---|
730 | break;
|
---|
731 | }
|
---|
732 | }
|
---|
733 |
|
---|
734 | /*
|
---|
735 | * Timeout/error case, clean up.
|
---|
736 | */
|
---|
737 | if (pThis->u32Magic == RTSEMRW_MAGIC)
|
---|
738 | {
|
---|
739 | RTCritSectEnter(&pThis->CritSect);
|
---|
740 | /* Adjust this counter, whether we got the critsect or not. */
|
---|
741 | pThis->cWritesWaiting--;
|
---|
742 | RTCritSectLeave(&pThis->CritSect);
|
---|
743 | }
|
---|
744 | return rc;
|
---|
745 | }
|
---|
746 |
|
---|
747 |
|
---|
748 | RTDECL(int) RTSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
|
---|
749 | {
|
---|
750 | #ifndef RTSEMRW_STRICT
|
---|
751 | return rtSemRWRequestWrite(hRWSem, cMillies, false, NULL);
|
---|
752 | #else
|
---|
753 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
|
---|
754 | return rtSemRWRequestWrite(hRWSem, cMillies, false, &SrcPos);
|
---|
755 | #endif
|
---|
756 | }
|
---|
757 | RT_EXPORT_SYMBOL(RTSemRWRequestWrite);
|
---|
758 |
|
---|
759 |
|
---|
760 | RTDECL(int) RTSemRWRequestWriteDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
|
---|
761 | {
|
---|
762 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
|
---|
763 | return rtSemRWRequestWrite(hRWSem, cMillies, false, &SrcPos);
|
---|
764 | }
|
---|
765 | RT_EXPORT_SYMBOL(RTSemRWRequestWriteDebug);
|
---|
766 |
|
---|
767 |
|
---|
768 | RTDECL(int) RTSemRWRequestWriteNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
|
---|
769 | {
|
---|
770 | #ifndef RTSEMRW_STRICT
|
---|
771 | return rtSemRWRequestWrite(hRWSem, cMillies, true, NULL);
|
---|
772 | #else
|
---|
773 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
|
---|
774 | return rtSemRWRequestWrite(hRWSem, cMillies, true, &SrcPos);
|
---|
775 | #endif
|
---|
776 | }
|
---|
777 | RT_EXPORT_SYMBOL(RTSemRWRequestWriteNoResume);
|
---|
778 |
|
---|
779 |
|
---|
780 | RTDECL(int) RTSemRWRequestWriteNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
|
---|
781 | {
|
---|
782 | RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
|
---|
783 | return rtSemRWRequestWrite(hRWSem, cMillies, true, &SrcPos);
|
---|
784 | }
|
---|
785 | RT_EXPORT_SYMBOL(RTSemRWRequestWriteNoResumeDebug);
|
---|
786 |
|
---|
787 |
|
---|
788 | RTDECL(int) RTSemRWReleaseWrite(RTSEMRW hRWSem)
|
---|
789 | {
|
---|
790 |
|
---|
791 | /*
|
---|
792 | * Validate handle.
|
---|
793 | */
|
---|
794 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
795 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
|
---|
796 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
|
---|
797 |
|
---|
798 | /*
|
---|
799 | * Take critsect.
|
---|
800 | */
|
---|
801 | int rc = RTCritSectEnter(&pThis->CritSect);
|
---|
802 | AssertRCReturn(rc, rc);
|
---|
803 |
|
---|
804 | /*
|
---|
805 | * Check if owner.
|
---|
806 | */
|
---|
807 | RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner;
|
---|
808 | if (pThis->hWriter != hNativeSelf)
|
---|
809 | {
|
---|
810 | RTCritSectLeave(&pThis->CritSect);
|
---|
811 | AssertMsgFailed(("Not read-write owner of rwsem %p.\n", hRWSem));
|
---|
812 | return VERR_NOT_OWNER;
|
---|
813 | }
|
---|
814 |
|
---|
815 | #ifdef RTSEMRW_STRICT
|
---|
816 | if (pThis->cWrites > 1 || !pThis->cWriterReads) /* don't check+release if VERR_WRONG_ORDER */
|
---|
817 | {
|
---|
818 | int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorWrite, pThis->cWrites == 1);
|
---|
819 | if (RT_FAILURE(rc9))
|
---|
820 | {
|
---|
821 | RTCritSectLeave(&pThis->CritSect);
|
---|
822 | return rc9;
|
---|
823 | }
|
---|
824 | }
|
---|
825 | #endif
|
---|
826 |
|
---|
827 | /*
|
---|
828 | * Release ownership and remove ourselves from the writers count.
|
---|
829 | */
|
---|
830 | Assert(pThis->cWrites > 0);
|
---|
831 | pThis->cWrites--;
|
---|
832 | if (!pThis->cWrites)
|
---|
833 | {
|
---|
834 | if (RT_UNLIKELY(pThis->cWriterReads > 0))
|
---|
835 | {
|
---|
836 | pThis->cWrites++;
|
---|
837 | RTCritSectLeave(&pThis->CritSect);
|
---|
838 | AssertMsgFailed(("All recursive read locks need to be released prior to the final write lock! (%p)n\n", pThis));
|
---|
839 | return VERR_WRONG_ORDER;
|
---|
840 | }
|
---|
841 |
|
---|
842 | pThis->hWriter = NIL_RTNATIVETHREAD;
|
---|
843 | }
|
---|
844 |
|
---|
845 | /*
|
---|
846 | * Release the readers if no more writers waiting, otherwise the writers.
|
---|
847 | */
|
---|
848 | if (!pThis->cWritesWaiting)
|
---|
849 | {
|
---|
850 | rc = RTSemEventMultiSignal(pThis->ReadEvent);
|
---|
851 | AssertMsgRC(rc, ("RTSemEventMultiSignal failed for rwsem %p, rc=%Rrc.\n", hRWSem, rc));
|
---|
852 | pThis->fNeedResetReadEvent = true;
|
---|
853 | }
|
---|
854 | else
|
---|
855 | {
|
---|
856 | rc = RTSemEventSignal(pThis->WriteEvent);
|
---|
857 | AssertMsgRC(rc, ("Failed to signal writers on rwsem %p, rc=%Rrc\n", hRWSem, rc));
|
---|
858 | }
|
---|
859 | RTCritSectLeave(&pThis->CritSect);
|
---|
860 |
|
---|
861 | return rc;
|
---|
862 | }
|
---|
863 | RT_EXPORT_SYMBOL(RTSemRWReleaseWrite);
|
---|
864 |
|
---|
865 |
|
---|
866 | RTDECL(bool) RTSemRWIsWriteOwner(RTSEMRW hRWSem)
|
---|
867 | {
|
---|
868 | /*
|
---|
869 | * Validate handle.
|
---|
870 | */
|
---|
871 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
872 | AssertPtrReturn(pThis, false);
|
---|
873 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, false);
|
---|
874 |
|
---|
875 | /*
|
---|
876 | * Check ownership.
|
---|
877 | */
|
---|
878 | RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
|
---|
879 | RTNATIVETHREAD hWriter;
|
---|
880 | ASMAtomicUoReadHandle(&pThis->hWriter, &hWriter);
|
---|
881 | return hWriter == hNativeSelf;
|
---|
882 | }
|
---|
883 | RT_EXPORT_SYMBOL(RTSemRWIsWriteOwner);
|
---|
884 |
|
---|
885 |
|
---|
886 | RTDECL(bool) RTSemRWIsReadOwner(RTSEMRW hRWSem, bool fWannaHear)
|
---|
887 | {
|
---|
888 | /*
|
---|
889 | * Validate handle.
|
---|
890 | */
|
---|
891 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
892 | AssertPtrReturn(pThis, false);
|
---|
893 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, false);
|
---|
894 |
|
---|
895 | /*
|
---|
896 | * Check write ownership. The writer is also a valid reader.
|
---|
897 | */
|
---|
898 | RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
|
---|
899 | RTNATIVETHREAD hWriter;
|
---|
900 | ASMAtomicUoReadHandle(&pThis->hWriter, &hWriter);
|
---|
901 | if (hWriter == hNativeSelf)
|
---|
902 | return true;
|
---|
903 | if (hWriter != NIL_RTNATIVETHREAD)
|
---|
904 | return false;
|
---|
905 |
|
---|
906 | #ifdef RTSEMRW_STRICT
|
---|
907 | /*
|
---|
908 | * Ask the lock validator.
|
---|
909 | */
|
---|
910 | NOREF(fWannaHear);
|
---|
911 | return RTLockValidatorRecSharedIsOwner(&pThis->ValidatorRead, NIL_RTTHREAD);
|
---|
912 | #else
|
---|
913 | /*
|
---|
914 | * If there are no reads we cannot be one of them... But if there are we
|
---|
915 | * cannot know and can only return what the caller want to hear.
|
---|
916 | */
|
---|
917 | if (pThis->cReads == 0)
|
---|
918 | return false;
|
---|
919 | return fWannaHear;
|
---|
920 | #endif
|
---|
921 | }
|
---|
922 | RT_EXPORT_SYMBOL(RTSemRWIsReadOwner);
|
---|
923 |
|
---|
924 |
|
---|
925 | RTDECL(uint32_t) RTSemRWGetWriteRecursion(RTSEMRW hRWSem)
|
---|
926 | {
|
---|
927 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
928 |
|
---|
929 | /*
|
---|
930 | * Validate handle.
|
---|
931 | */
|
---|
932 | AssertPtrReturn(pThis, 0);
|
---|
933 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, 0);
|
---|
934 |
|
---|
935 | /*
|
---|
936 | * Return the requested data.
|
---|
937 | */
|
---|
938 | return pThis->cWrites;
|
---|
939 | }
|
---|
940 | RT_EXPORT_SYMBOL(RTSemRWGetWriteRecursion);
|
---|
941 |
|
---|
942 |
|
---|
943 | RTDECL(uint32_t) RTSemRWGetWriterReadRecursion(RTSEMRW hRWSem)
|
---|
944 | {
|
---|
945 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
946 |
|
---|
947 | /*
|
---|
948 | * Validate handle.
|
---|
949 | */
|
---|
950 | AssertPtrReturn(pThis, 0);
|
---|
951 | AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, 0);
|
---|
952 |
|
---|
953 | /*
|
---|
954 | * Return the requested data.
|
---|
955 | */
|
---|
956 | return pThis->cWriterReads;
|
---|
957 | }
|
---|
958 | RT_EXPORT_SYMBOL(RTSemRWGetWriterReadRecursion);
|
---|
959 |
|
---|
960 |
|
---|
961 | RTDECL(uint32_t) RTSemRWGetReadCount(RTSEMRW hRWSem)
|
---|
962 | {
|
---|
963 | /*
|
---|
964 | * Validate input.
|
---|
965 | */
|
---|
966 | struct RTSEMRWINTERNAL *pThis = hRWSem;
|
---|
967 | AssertPtrReturn(pThis, 0);
|
---|
968 | AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
|
---|
969 | ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
|
---|
970 | 0);
|
---|
971 |
|
---|
972 | /*
|
---|
973 | * Return the requested data.
|
---|
974 | */
|
---|
975 | return pThis->cReads;
|
---|
976 | }
|
---|
977 | RT_EXPORT_SYMBOL(RTSemRWGetReadCount);
|
---|
978 |
|
---|