564 lines
18 KiB
C
564 lines
18 KiB
C
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/* **********************************************************
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* Copyright 2004 - 2009 VMware, Inc. All rights reserved.
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* **********************************************************/
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/*
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* @VMKAPIMOD_LICENSE@
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*/
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/*
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***********************************************************************
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* Semaphores */ /**
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* \defgroup Semaphores Semaphores
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*
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* \par Binary Semaphore Ranks:
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* Binary semaphores are semaphores which may be treated like blocking
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* locks. As such, they take a rank and sub-rank in a manner analogous
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* the the lock ranking used for spinlocks.\n
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* \n
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* When a world locks a binary semaphore \em BS1 with major rank \em R1 and
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* minor rank \em r1, it may only lock another binary semaphore BS2 with
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* major rank \em R2 and minor rank \em r2 when:
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* \n
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* \em R2 > \em R1 \n
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* or \n
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* \em R2 == \em R1 and \em r2 > \em r1 \n
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* \n
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* Be aware that rank checking is only performed on debug builds.
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* @{
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***********************************************************************
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*/
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#ifndef _VMKAPI_SEM_H_
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#define _VMKAPI_SEM_H_
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/** \cond never */
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#ifndef VMK_HEADER_INCLUDED_FROM_VMKAPI_H
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#error This vmkapi file should never be included directly but only via vmkapi.h
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#endif
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/** \endcond never */
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#include "base/vmkapi_types.h"
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#include "base/vmkapi_module.h"
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#include "base/vmkapi_status.h"
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/** \cond nodoc */
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/* Private definitions */
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#define _VMK_SEMA_RANK_UNRANKED 0x10000
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#define _VMK_SEMA_RANK_MAX 0xffff
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#define _VMK_SEMA_RANK_MIN 0
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#define _VMK_SEMA_RANK_LEAF _VMK_SEMA_RANK_MAX
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#define _VMK_SEMA_RANK_STORAGE 0x8000
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typedef vmk_uint32 _vmk_SemaRank, _vmk_SemaRankMinor;
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/** \endcond nodoc */
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/**
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* \brief unranked rank
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*/
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#define VMK_SEMA_RANK_UNRANKED _VMK_SEMA_RANK_UNRANKED
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/**
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* \brief Leaf rank for semaphores
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*/
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#define VMK_SEMA_RANK_LEAF _VMK_SEMA_RANK_LEAF
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/**
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* \brief Maximum rank for semaphores
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*/
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#define VMK_SEMA_RANK_MAX _VMK_SEMA_RANK_MAX
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/**
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* \brief Minimum rank for semaphores
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*/
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#define VMK_SEMA_RANK_MIN _VMK_SEMA_RANK_MIN
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/**
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* \brief Rank for semaphores in storage components
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*/
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#define VMK_SEMA_RANK_STORAGE _VMK_SEMA_RANK_STORAGE
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/**
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* \brief Rank for semaphores
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*/
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typedef _vmk_SemaRank vmk_SemaphoreRank;
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/**
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* \brief Sub rank for semaphores
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*/
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typedef _vmk_SemaRankMinor vmk_SemaphoreRankMinor;
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/**
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* \brief Opaque handle for semaphores
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*/
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typedef struct vmk_SemaphoreInt *vmk_Semaphore;
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/**
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* \brief Opaque handle for readers-writers semaphores
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*/
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typedef struct vmk_SemaphoreRWInt *vmk_SemaphoreRW;
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/*
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***********************************************************************
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* vmk_SemaCreate -- */ /**
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*
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* \ingroup Semaphores
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* \brief Allocate and initialize a counting semaphore
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*
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* \note Requires that the module heap be initialized.
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*
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* \param[out] sema New counting semaphore.
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* \param[in] moduleID Module on whose behalf the semaphore
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* is created.
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* \param[in] name Human-readable name of the semaphore.
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* \param[in] value Initial count.
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*
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* \retval VMK_OK The semaphore was successfully created
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* \retval VMK_NO_MEMORY The semaphore could not be allocated
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* \retval VMK_NO_MODULE_HEAP The module has no heap to allocate from
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*
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***********************************************************************
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*/
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VMK_ReturnStatus vmk_SemaCreate(
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vmk_Semaphore *sema,
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vmk_ModuleID moduleID,
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const char *name,
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vmk_int32 value);
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/*
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***********************************************************************
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* vmk_BinarySemaCreate -- */ /**
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*
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* \ingroup Semaphores
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* \brief Allocate and initialize a binary semaphore
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*
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* \note Requires that the module heap be initialized.
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*
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* \param[out] sema New counting semaphore.
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* \param[in] moduleID Module on whose behalf the semaphore
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* is created.
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* \param[in] name Human-readable name of the semaphore.
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* \param[in] majorRank Major rank of the semaphore.
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* The rank value must be greater than or
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* equal to VMK_SEMA_RANK_MIN and less than
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* or equal to VMK_SEMA_RANK_MAX.
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* \param[in] minorRank Minor rank of the semaphore.
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* The rank value must be greater than or
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* equal to VMK_SEMA_RANK_MIN and less than
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* or equal to VMK_SEMA_RANK_MAX.
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*
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* \retval VMK_OK The semaphore was successfully created
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* \retval VMK_NO_MEMORY The semaphore could not be allocated
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* \retval VMK_NO_MODULE_HEAP The module has no heap to allocate from
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*
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***********************************************************************
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*/
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VMK_ReturnStatus vmk_BinarySemaCreate(
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vmk_Semaphore *sema,
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vmk_ModuleID moduleID,
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const char *name,
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vmk_SemaphoreRank majorRank,
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vmk_SemaphoreRankMinor minorRank);
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/*
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***********************************************************************
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* _vmkSemaIsLocked
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*
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* This is used by VMK_ASSERT_SEMA_LOCKED and VMK_ASSERT_SEMA_UNLOCKED.
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* VMKAPI users should not call this function directly.
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*
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***********************************************************************
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*/
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/** \cond nodoc */
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VMK_ReturnStatus _vmkSemaIsLocked(
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vmk_Semaphore *sema,
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vmk_Bool *isLocked);
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/** \endcond */
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/*
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***********************************************************************
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* VMK_ASSERT_SEMA_LOCKED -- */ /**
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*
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* \ingroup Semaphores
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* \brief Assert that a semaphore is currently locked only in
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* debug builds.
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*
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* \param[in] sema Semaphore to check.
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*
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***********************************************************************
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*/
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#if defined(VMX86_DEBUG)
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#define VMK_ASSERT_SEMA_LOCKED(sema) \
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do { \
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vmk_Bool _vmkCheckLockState ; \
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VMK_ASSERT(_vmkSemaIsLocked((sema),&_vmkCheckLockState) == \
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VMK_OK); \
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VMK_ASSERT(_vmkCheckLockState); \
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} while(0)
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#else
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#define VMK_ASSERT_SEMA_LOCKED(sema)
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#endif
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/*
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***********************************************************************
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* VMK_ASSERT_SEMA_UNLOCKED -- */ /**
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*
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* \ingroup Semaphores
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* \brief Assert that a semaphore is currently unlocked only in
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* debug builds.
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*
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* \param[in] sema Semaphore to check.
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*
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***********************************************************************
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*/
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#if defined(VMX86_DEBUG)
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#define VMK_ASSERT_SEMA_UNLOCKED(sema) \
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do { \
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vmk_Bool _vmkCheckLockState ; \
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VMK_ASSERT(_vmkSemaIsLocked((sema),&_vmkCheckLockState) == \
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VMK_OK); \
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VMK_ASSERT(!_vmkCheckLockState); \
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} while(0)
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#else
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#define VMK_ASSERT_SEMA_UNLOCKED(sema)
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#endif
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/*
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***********************************************************************
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* vmk_SemaLock -- */ /**
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*
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* \ingroup Semaphores
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* \brief Acquire a semaphore
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*
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* \pre Shall be called from a blockable context.
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* \pre The caller shall not already hold a semaphore of lower or equal
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* rank if the semaphore is a binary semaphore.
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*
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* \param[in] sema The semaphore to acquire.
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*
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***********************************************************************
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*/
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void vmk_SemaLock(
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vmk_Semaphore *sema);
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/*
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***********************************************************************
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* vmk_SemaTryLock -- */ /**
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*
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* \ingroup Semaphores
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* \brief Try to acquire a semaphore.
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*
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* This tries to acquire the given semaphore once.
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* If the semaphore is already locked, it returns immediately.
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*
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* \pre Shall be called from a blockable context.
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*
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* \param[in] sema Semaphore to attempt to acquire.
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*
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* \retval VMK_OK The semaphore was successfully acquired.
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* \retval VMK_BUSY The semaphore is currently locked.
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*
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***********************************************************************
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*/
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VMK_ReturnStatus vmk_SemaTryLock(
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vmk_Semaphore *sema);
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/*
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***********************************************************************
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* vmk_SemaUnlock -- */ /**
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*
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* \ingroup Semaphores
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* \brief Release a semaphore
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*
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* \param[in] sema Semaphore to unlock.
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*
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***********************************************************************
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*/
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void vmk_SemaUnlock(
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vmk_Semaphore *sema);
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/*
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***********************************************************************
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* vmk_SemaDestroy -- */ /**
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*
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* \ingroup Semaphores
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* \brief Destroy a semaphore
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*
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* Revert all side effects of vmk_SemaCreate or vmk_BinarySemaCreate.
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*
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* \param[in] sema Semaphore to destroy.
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*
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***********************************************************************
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*/
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void vmk_SemaDestroy(vmk_Semaphore *sema);
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/*
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***********************************************************************
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* VMK_ASSERT_RWSEMA_HAS_READERS -- */ /**
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*
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* \ingroup Semaphores
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* \brief Assert that a readers-writers semaphore has at least one
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* shared reader only in debug builds.
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*
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* \param[in] sema Semaphore to check.
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*
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***********************************************************************
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*/
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#if defined(VMX86_DEBUG)
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#define VMK_ASSERT_RWSEMA_HAS_READERS(sema) \
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do { \
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VMK_ASSERT(vmk_RWSemaHasReaders(sema) == VMK_TRUE); \
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} while(0)
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#else
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#define VMK_ASSERT_RWSEMA_HAS_READERS(sema)
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#endif
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/*
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***********************************************************************
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* VMK_ASSERT_RWSEMA_HAS_WRITER -- */ /**
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*
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* \ingroup Semaphores
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* \brief Assert that a readers-writers semaphore has a writer only in
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* debug builds.
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*
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* \param[in] sema Semaphore to check.
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*
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***********************************************************************
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*/
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#if defined(VMX86_DEBUG)
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#define VMK_ASSERT_RWSEMA_HAS_WRITER(sema) \
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do { \
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VMK_ASSERT(vmk_RWSemaHasWriter(sema) == VMK_TRUE); \
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} while(0)
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#else
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#define VMK_ASSERT_RWSEMA_HAS_WRITER(sema)
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#endif
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/*
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***********************************************************************
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* VMK_ASSERT_RWSEMA_HAS_READERS_WRITERS -- */ /**
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*
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* \ingroup Semaphores
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* \brief Assert that a readers-writers semaphore has a writer only in
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* debug builds.
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*
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* \param[in] sema Semaphore to check.
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*
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***********************************************************************
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*/
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#if defined(VMX86_DEBUG)
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#define VMK_ASSERT_RWSEMA_HAS_READERS_WRITERS(sema) \
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do { \
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VMK_ASSERT(vmk_RWSemaHasReadersWriters(sema) == VMK_TRUE); \
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} while(0)
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#else
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#define VMK_ASSERT_RWSEMA_HAS_READERS_WRITERS(sema)
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#endif
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/*
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***********************************************************************
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* vmk_RWSemaCreate -- */ /**
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*
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* \ingroup Semaphores
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* \brief Allocate and initialize a readers-writers semaphore
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*
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* \param[out] sema New readers-writers semaphore.
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* \param[in] moduleID Module on whose behalf the semaphore
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* is created.
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* \param[in] name Human-readable name of the semaphore.
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*
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***********************************************************************
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*/
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VMK_ReturnStatus vmk_RWSemaCreate(
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vmk_SemaphoreRW *sema,
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vmk_ModuleID moduleID,
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const char *name);
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/*
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***********************************************************************
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* vmk_RWSemaDestroy -- */ /**
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*
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* \ingroup Semaphores
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* \brief Destroy a readers-writers semaphore
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*
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||
|
|
* Revert all side effects of vmk_RWSemaCreate.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to destroy.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
void vmk_RWSemaDestroy(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_RWSemaReadLock -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Acquire a readers-writers semaphore for shared read access.
|
||
|
|
*
|
||
|
|
* \pre Shall be called from a blockable context.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to acquire.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
void vmk_RWSemaReadLock(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_RWSemaWriteLock -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Acquire a readers-writers semaphore for exclusive write
|
||
|
|
* access.
|
||
|
|
*
|
||
|
|
* \pre Shall be called from a blockable context.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to acquire.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
void vmk_RWSemaWriteLock(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_RWSemaReadUnlock -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Release a readers-writers semaphore from shared read access.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to release.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
void vmk_RWSemaReadUnlock(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_RWSemaWriteUnlock -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Release a readers-writers semaphore from exclusive write
|
||
|
|
* access.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to release.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
void vmk_RWSemaWriteUnlock(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_RWSemaUpgradeFromRead -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Upgrade a readers-writers semaphore to exclusive write access.
|
||
|
|
*
|
||
|
|
* This requests an upgrade to exclusive writers access for the
|
||
|
|
* readers-writers semaphore while already holding shared reader access.
|
||
|
|
* If the upgrade is not immediately available, only the first caller
|
||
|
|
* can block waiting for the upgrade. Others fail, but they retain
|
||
|
|
* shared reader access.
|
||
|
|
*
|
||
|
|
* \pre Shall be called from a blockable context.
|
||
|
|
* \pre Shall already have read access to the semaphore.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to upgrade.
|
||
|
|
*
|
||
|
|
* \retval VMK_OK The semaphore was upgraded.
|
||
|
|
* \retval VMK_BUSY The semaphore could not be upgraded.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
VMK_ReturnStatus vmk_RWSemaUpgradeFromRead(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_RWSemaTryUpgradeFromRead -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Attempt to upgrade a readers-writers semaphore to
|
||
|
|
* exclusive write access.
|
||
|
|
*
|
||
|
|
* This attempts to obtain exclusive writers access to the
|
||
|
|
* readers-writers semaphore while already holding shared reader access.
|
||
|
|
* If the upgrade is not immediately available, shared reader access
|
||
|
|
* is retained.
|
||
|
|
*
|
||
|
|
* \pre Shall already have read access to the semaphore.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to upgrade.
|
||
|
|
*
|
||
|
|
* \retval VMK_OK The semaphore was upgraded.
|
||
|
|
* \retval VMK_BUSY The semaphore could not be upgraded.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
VMK_ReturnStatus vmk_RWSemaTryUpgradeFromRead(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_RWSemaDowngradeToRead -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Downgrade a readers-writers semaphore from exclusive
|
||
|
|
* write access to shared read access.
|
||
|
|
*
|
||
|
|
* \pre Shall already have write access to the semaphore.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to downgrade.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
void vmk_RWSemaDowngradeToRead(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_RWSemaHasReaders -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Determine if a readers-writers semaphore currently has one or
|
||
|
|
* more readers.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to inspect.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
vmk_Bool vmk_RWSemaHasReaders(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_SemaHasWriter -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Determine if a readers-writers semaphore currently has
|
||
|
|
* a writer.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to inspect.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
vmk_Bool vmk_RWSemaHasWriter(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
/*
|
||
|
|
***********************************************************************
|
||
|
|
* vmk_SemaHasReadersWriters -- */ /**
|
||
|
|
*
|
||
|
|
* \ingroup Semaphores
|
||
|
|
* \brief Determine if a readers-writers semaphore currently has any
|
||
|
|
* readers or an exclusive writer.
|
||
|
|
*
|
||
|
|
* \param[in] sema Readers-writers semaphore to inspect.
|
||
|
|
*
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
vmk_Bool vmk_RWSemaHasReadersWriters(vmk_SemaphoreRW *sema);
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
#endif /* _VMKAPI_SEM_H_ */
|
||
|
|
/** @} */
|