semmutex-r0drv-linux.c revision 8f79fbb852ac192bf1b2ee23594f933662d14632
/* $Id$ */
/** @file
* IPRT - Mutex Semaphores, Ring-0 Driver, Linux.
*/
/*
* Copyright (C) 2006-2007 Sun Microsystems, Inc.
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 USA or visit http://www.sun.com if you need
* additional information or have any questions.
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
#include "the-linux-kernel.h"
#include "internal/iprt.h"
#include <iprt/semaphore.h>
#include <iprt/alloc.h>
#include <iprt/assert.h>
#include <iprt/asm.h>
#include <iprt/err.h>
#include "internal/magics.h"
/*******************************************************************************
* Structures and Typedefs *
*******************************************************************************/
/**
* Linux mutex semaphore.
*/
typedef struct RTSEMMUTEXINTERNAL
{
/** Magic value (RTSEMMUTEX_MAGIC). */
uint32_t volatile u32Magic;
/** Number of recursive locks - 0 if not owned by anyone, > 0 if owned. */
uint32_t volatile cRecursion;
/** The wait queue. */
wait_queue_head_t Head;
/** The current owner. */
void * volatile pOwner;
} RTSEMMUTEXINTERNAL, *PRTSEMMUTEXINTERNAL;
/* Undefine debug mappings. */
#undef RTSemMutexRequest
#undef RTSemMutexRequestNoResume
RTDECL(int) RTSemMutexCreate(PRTSEMMUTEX pMutexSem)
{
PRTSEMMUTEXINTERNAL pMutexInt = (PRTSEMMUTEXINTERNAL)RTMemAlloc(sizeof(*pMutexInt));
if (pMutexInt)
{
pMutexInt->u32Magic = RTSEMMUTEX_MAGIC;
init_waitqueue_head(&pMutexInt->Head);
*pMutexSem = pMutexInt;
AssertReleaseMsgFailed(("This mutex implementation is buggy, fix it!\n"));
return VINF_SUCCESS;
}
return VERR_NO_MEMORY;
}
RT_EXPORT_SYMBOL(RTSemMutexCreate);
RTDECL(int) RTSemMutexDestroy(RTSEMMUTEX MutexSem)
{
/*
* Validate input.
*/
PRTSEMMUTEXINTERNAL pMutexInt = (PRTSEMMUTEXINTERNAL)MutexSem;
if (!pMutexInt)
return VERR_INVALID_PARAMETER;
if (pMutexInt->u32Magic != RTSEMMUTEX_MAGIC)
{
AssertMsgFailed(("pMutexInt->u32Magic=%RX32 pMutexInt=%p\n", pMutexInt->u32Magic, pMutexInt));
return VERR_INVALID_PARAMETER;
}
/*
* Invalidate it and signal the object just in case.
*/
ASMAtomicIncU32(&pMutexInt->u32Magic);
ASMAtomicXchgU32(&pMutexInt->cRecursion, 0);
Assert(!waitqueue_active(&pMutexInt->Head));
wake_up_all(&pMutexInt->Head);
RTMemFree(pMutexInt);
return VINF_SUCCESS;
}
RT_EXPORT_SYMBOL(RTSemMutexDestroy);
RTDECL(int) RTSemMutexRequest(RTSEMMUTEX MutexSem, unsigned cMillies)
{
/*
* Validate input.
*/
PRTSEMMUTEXINTERNAL pMutexInt = (PRTSEMMUTEXINTERNAL)MutexSem;
if (!pMutexInt)
return VERR_INVALID_PARAMETER;
if ( !pMutexInt
|| pMutexInt->u32Magic != RTSEMMUTEX_MAGIC)
{
AssertMsgFailed(("pMutexInt->u32Magic=%RX32 pMutexInt=%p\n", pMutexInt ? pMutexInt->u32Magic : 0, pMutexInt));
return VERR_INVALID_PARAMETER;
}
/*
* Check for recursive request.
*/
if (pMutexInt->pOwner == current)
{
Assert(pMutexInt->cRecursion < 1000);
ASMAtomicIncU32(&pMutexInt->cRecursion);
return VINF_SUCCESS;
}
/*
* Try aquire it.
*/
if (ASMAtomicCmpXchgU32(&pMutexInt->cRecursion, 1, 0))
{
ASMAtomicXchgPtr(&pMutexInt->pOwner, current);
return VINF_SUCCESS;
}
else
{
/*
* Ok wait for it.
*/
DEFINE_WAIT(Wait);
int rc = VINF_SUCCESS;
long lTimeout = cMillies == RT_INDEFINITE_WAIT ? MAX_SCHEDULE_TIMEOUT : msecs_to_jiffies(cMillies);
for (;;)
{
/* make everything thru schedule() atomic scheduling wise. */
prepare_to_wait(&pMutexInt->Head, &Wait, TASK_INTERRUPTIBLE);
/* check the condition. */
if (ASMAtomicCmpXchgU32(&pMutexInt->cRecursion, 1, 0))
{
ASMAtomicXchgPtr(&pMutexInt->pOwner, current);
break;
}
/* check for pending signals. */
if (signal_pending(current))
{
rc = VERR_INTERRUPTED; /** @todo VERR_INTERRUPTED isn't correct anylonger. please fix r0drv stuff! */
break;
}
/* wait */
lTimeout = schedule_timeout(lTimeout);
after_wait(&Wait);
/* Check if someone destroyed the semaphore while we was waiting. */
if (pMutexInt->u32Magic != RTSEMMUTEX_MAGIC)
{
rc = VERR_SEM_DESTROYED;
break;
}
/* check for timeout. */
if (!lTimeout)
{
rc = VERR_TIMEOUT;
break;
}
}
finish_wait(&pMutexInt->Head, &Wait);
return rc;
}
return VINF_SUCCESS;
}
RT_EXPORT_SYMBOL(RTSemMutexRequest);
RTDECL(int) RTSemMutexRelease(RTSEMMUTEX MutexSem)
{
/*
* Validate input.
*/
PRTSEMMUTEXINTERNAL pMutexInt = (PRTSEMMUTEXINTERNAL)MutexSem;
if (!pMutexInt)
return VERR_INVALID_PARAMETER;
if ( !pMutexInt
|| pMutexInt->u32Magic != RTSEMMUTEX_MAGIC)
{
AssertMsgFailed(("pMutexInt->u32Magic=%RX32 pMutexInt=%p\n", pMutexInt ? pMutexInt->u32Magic : 0, pMutexInt));
return VERR_INVALID_PARAMETER;
}
if (pMutexInt->pOwner != current)
{
AssertMsgFailed(("Not owner, pOwner=%p current=%p\n", (void *)pMutexInt->pOwner, (void *)current));
return VERR_NOT_OWNER;
}
/*
* Release the mutex.
*/
if (pMutexInt->cRecursion == 1)
{
ASMAtomicXchgPtr(&pMutexInt->pOwner, NULL);
ASMAtomicXchgU32(&pMutexInt->cRecursion, 0);
}
else
ASMAtomicDecU32(&pMutexInt->cRecursion);
return VINF_SUCCESS;
}
RT_EXPORT_SYMBOL(RTSemMutexRelease);