/* $Id$ */
/** @file
* IPRT - File async I/O, native implementation for the FreeBSD host platform.
*/
/*
* Copyright (C) 2006-2011 Oracle Corporation
*
* 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.
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
#define LOG_GROUP RTLOGGROUP_FILE
#include <iprt/asm.h>
#include <iprt/file.h>
#include <iprt/mem.h>
#include <iprt/assert.h>
#include <iprt/string.h>
#include <iprt/err.h>
#include <iprt/log.h>
#include <iprt/thread.h>
#include "internal/fileaio.h"
#include <sys/types.h>
#include <sys/event.h>
#include <sys/time.h>
#include <sys/sysctl.h>
#include <aio.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
/*******************************************************************************
* Structures and Typedefs *
*******************************************************************************/
/**
* Async I/O completion context state.
*/
typedef struct RTFILEAIOCTXINTERNAL
{
/** Handle to the kernel queue. */
int iKQueue;
/** Current number of requests active on this context. */
volatile int32_t cRequests;
/** The ID of the thread which is currently waiting for requests. */
volatile RTTHREAD hThreadWait;
/** Flag whether the thread was woken up. */
volatile bool fWokenUp;
/** Flag whether the thread is currently waiting in the syscall. */
volatile bool fWaiting;
/** Flags given during creation. */
uint32_t fFlags;
/** Magic value (RTFILEAIOCTX_MAGIC). */
uint32_t u32Magic;
} RTFILEAIOCTXINTERNAL;
/** Pointer to an internal context structure. */
typedef RTFILEAIOCTXINTERNAL *PRTFILEAIOCTXINTERNAL;
/**
* Async I/O request state.
*/
typedef struct RTFILEAIOREQINTERNAL
{
/** The aio control block. Must be the FIRST
* element. */
struct aiocb AioCB;
/** Current state the request is in. */
RTFILEAIOREQSTATE enmState;
/** Flag whether this is a flush request. */
bool fFlush;
/** Opaque user data. */
void *pvUser;
/** Completion context we are assigned to. */
PRTFILEAIOCTXINTERNAL pCtxInt;
/** Number of bytes actually transferred. */
size_t cbTransfered;
/** Status code. */
int Rc;
/** Magic value (RTFILEAIOREQ_MAGIC). */
uint32_t u32Magic;
} RTFILEAIOREQINTERNAL;
/** Pointer to an internal request structure. */
typedef RTFILEAIOREQINTERNAL *PRTFILEAIOREQINTERNAL;
/*******************************************************************************
* Defined Constants And Macros *
*******************************************************************************/
/** The max number of events to get in one call. */
#define AIO_MAXIMUM_REQUESTS_PER_CONTEXT 64
RTR3DECL(int) RTFileAioGetLimits(PRTFILEAIOLIMITS pAioLimits)
{
int rcBSD = 0;
AssertPtrReturn(pAioLimits, VERR_INVALID_POINTER);
/*
* The AIO API is implemented in a kernel module which is not
* loaded by default.
* If it is loaded there are additional sysctl parameters.
*/
int cReqsOutstandingMax = 0;
size_t cbParameter = sizeof(int);
rcBSD = sysctlbyname("vfs.aio.max_aio_per_proc", /* name */
&cReqsOutstandingMax, /* Where to store the old value. */
&cbParameter, /* Size of the memory pointed to. */
NULL, /* Where the new value is located. */
0); /* Where the size of the new value is stored. */
if (rcBSD == -1)
{
/* ENOENT means the value is unknown thus the module is not loaded. */
if (errno == ENOENT)
return VERR_NOT_SUPPORTED;
else
return RTErrConvertFromErrno(errno);
}
pAioLimits->cReqsOutstandingMax = cReqsOutstandingMax;
pAioLimits->cbBufferAlignment = 0;
return VINF_SUCCESS;
}
RTR3DECL(int) RTFileAioReqCreate(PRTFILEAIOREQ phReq)
{
AssertPtrReturn(phReq, VERR_INVALID_POINTER);
PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOREQINTERNAL));
if (RT_UNLIKELY(!pReqInt))
return VERR_NO_MEMORY;
/* Ininitialize static parts. */
pReqInt->AioCB.aio_sigevent.sigev_notify = SIGEV_KEVENT;
pReqInt->AioCB.aio_sigevent.sigev_value.sival_ptr = pReqInt;
pReqInt->pCtxInt = NULL;
pReqInt->u32Magic = RTFILEAIOREQ_MAGIC;
RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
*phReq = (RTFILEAIOREQ)pReqInt;
return VINF_SUCCESS;
}
RTDECL(int) RTFileAioReqDestroy(RTFILEAIOREQ hReq)
{
/*
* Validate the handle and ignore nil.
*/
if (hReq == NIL_RTFILEAIOREQ)
return VINF_SUCCESS;
PRTFILEAIOREQINTERNAL pReqInt = hReq;
RTFILEAIOREQ_VALID_RETURN(pReqInt);
RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
/*
* Trash the magic and free it.
*/
ASMAtomicUoWriteU32(&pReqInt->u32Magic, ~RTFILEAIOREQ_MAGIC);
RTMemFree(pReqInt);
return VINF_SUCCESS;
}
/**
* Worker setting up the request.
*/
DECLINLINE(int) rtFileAioReqPrepareTransfer(RTFILEAIOREQ hReq, RTFILE hFile,
unsigned uTransferDirection,
RTFOFF off, void *pvBuf, size_t cbTransfer,
void *pvUser)
{
/*
* Validate the input.
*/
PRTFILEAIOREQINTERNAL pReqInt = hReq;
RTFILEAIOREQ_VALID_RETURN(pReqInt);
RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
Assert(hFile != NIL_RTFILE);
AssertPtr(pvBuf);
Assert(off >= 0);
Assert(cbTransfer > 0);
pReqInt->AioCB.aio_sigevent.sigev_notify = SIGEV_KEVENT;
pReqInt->AioCB.aio_sigevent.sigev_value.sival_ptr = pReqInt;
pReqInt->AioCB.aio_lio_opcode = uTransferDirection;
pReqInt->AioCB.aio_fildes = RTFileToNative(hFile);
pReqInt->AioCB.aio_offset = off;
pReqInt->AioCB.aio_nbytes = cbTransfer;
pReqInt->AioCB.aio_buf = pvBuf;
pReqInt->fFlush = false;
pReqInt->pvUser = pvUser;
pReqInt->pCtxInt = NULL;
pReqInt->Rc = VERR_FILE_AIO_IN_PROGRESS;
RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
return VINF_SUCCESS;
}
RTDECL(int) RTFileAioReqPrepareRead(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
void *pvBuf, size_t cbRead, void *pvUser)
{
return rtFileAioReqPrepareTransfer(hReq, hFile, LIO_READ,
off, pvBuf, cbRead, pvUser);
}
RTDECL(int) RTFileAioReqPrepareWrite(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
void const *pvBuf, size_t cbWrite, void *pvUser)
{
return rtFileAioReqPrepareTransfer(hReq, hFile, LIO_WRITE,
off, (void *)pvBuf, cbWrite, pvUser);
}
RTDECL(int) RTFileAioReqPrepareFlush(RTFILEAIOREQ hReq, RTFILE hFile, void *pvUser)
{
PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)hReq;
RTFILEAIOREQ_VALID_RETURN(pReqInt);
Assert(hFile != NIL_RTFILE);
RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
pReqInt->fFlush = true;
pReqInt->AioCB.aio_fildes = RTFileToNative(hFile);
pReqInt->AioCB.aio_offset = 0;
pReqInt->AioCB.aio_nbytes = 0;
pReqInt->AioCB.aio_buf = NULL;
pReqInt->pvUser = pvUser;
RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
return VINF_SUCCESS;
}
RTDECL(void *) RTFileAioReqGetUser(RTFILEAIOREQ hReq)
{
PRTFILEAIOREQINTERNAL pReqInt = hReq;
RTFILEAIOREQ_VALID_RETURN_RC(pReqInt, NULL);
return pReqInt->pvUser;
}
RTDECL(int) RTFileAioReqCancel(RTFILEAIOREQ hReq)
{
PRTFILEAIOREQINTERNAL pReqInt = hReq;
RTFILEAIOREQ_VALID_RETURN(pReqInt);
RTFILEAIOREQ_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_NOT_SUBMITTED);
int rcBSD = aio_cancel(pReqInt->AioCB.aio_fildes, &pReqInt->AioCB);
if (rcBSD == AIO_CANCELED)
{
/*
* Decrement request count because the request will never arrive at the
* completion port.
*/
AssertMsg(VALID_PTR(pReqInt->pCtxInt),
("Invalid state. Request was canceled but wasn't submitted\n"));
ASMAtomicDecS32(&pReqInt->pCtxInt->cRequests);
pReqInt->Rc = VERR_FILE_AIO_CANCELED;
RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
return VINF_SUCCESS;
}
else if (rcBSD == AIO_ALLDONE)
return VERR_FILE_AIO_COMPLETED;
else if (rcBSD == AIO_NOTCANCELED)
return VERR_FILE_AIO_IN_PROGRESS;
else
return RTErrConvertFromErrno(errno);
}
RTDECL(int) RTFileAioReqGetRC(RTFILEAIOREQ hReq, size_t *pcbTransfered)
{
PRTFILEAIOREQINTERNAL pReqInt = hReq;
RTFILEAIOREQ_VALID_RETURN(pReqInt);
AssertPtrNull(pcbTransfered);
RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, PREPARED, VERR_FILE_AIO_NOT_SUBMITTED);
if ( (RT_SUCCESS(pReqInt->Rc))
&& (pcbTransfered))
*pcbTransfered = pReqInt->cbTransfered;
return pReqInt->Rc;
}
RTDECL(int) RTFileAioCtxCreate(PRTFILEAIOCTX phAioCtx, uint32_t cAioReqsMax,
uint32_t fFlags)
{
int rc = VINF_SUCCESS;
PRTFILEAIOCTXINTERNAL pCtxInt;
AssertPtrReturn(phAioCtx, VERR_INVALID_POINTER);
AssertReturn(!(fFlags & ~RTFILEAIOCTX_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
pCtxInt = (PRTFILEAIOCTXINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOCTXINTERNAL));
if (RT_UNLIKELY(!pCtxInt))
return VERR_NO_MEMORY;
/* Init the event handle. */
pCtxInt->iKQueue = kqueue();
if (RT_LIKELY(pCtxInt->iKQueue > 0))
{
pCtxInt->fFlags = fFlags;
pCtxInt->u32Magic = RTFILEAIOCTX_MAGIC;
*phAioCtx = (RTFILEAIOCTX)pCtxInt;
}
else
{
RTMemFree(pCtxInt);
rc = RTErrConvertFromErrno(errno);
}
return rc;
}
RTDECL(int) RTFileAioCtxDestroy(RTFILEAIOCTX hAioCtx)
{
/* Validate the handle and ignore nil. */
if (hAioCtx == NIL_RTFILEAIOCTX)
return VINF_SUCCESS;
PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
RTFILEAIOCTX_VALID_RETURN(pCtxInt);
/* Cannot destroy a busy context. */
if (RT_UNLIKELY(pCtxInt->cRequests))
return VERR_FILE_AIO_BUSY;
close(pCtxInt->iKQueue);
ASMAtomicUoWriteU32(&pCtxInt->u32Magic, RTFILEAIOCTX_MAGIC_DEAD);
RTMemFree(pCtxInt);
return VINF_SUCCESS;
}
RTDECL(uint32_t) RTFileAioCtxGetMaxReqCount(RTFILEAIOCTX hAioCtx)
{
return RTFILEAIO_UNLIMITED_REQS;
}
RTDECL(int) RTFileAioCtxAssociateWithFile(RTFILEAIOCTX hAioCtx, RTFILE hFile)
{
return VINF_SUCCESS;
}
RTDECL(int) RTFileAioCtxSubmit(RTFILEAIOCTX hAioCtx, PRTFILEAIOREQ pahReqs, size_t cReqs)
{
/*
* Parameter validation.
*/
int rc = VINF_SUCCESS;
PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
RTFILEAIOCTX_VALID_RETURN(pCtxInt);
AssertReturn(cReqs > 0, VERR_INVALID_PARAMETER);
AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
do
{
int rcBSD = 0;
size_t cReqsSubmit = 0;
size_t i = 0;
PRTFILEAIOREQINTERNAL pReqInt;
while ( (i < cReqs)
&& (i < AIO_LISTIO_MAX))
{
pReqInt = pahReqs[i];
if (RTFILEAIOREQ_IS_NOT_VALID(pReqInt))
{
/* Undo everything and stop submitting. */
for (size_t iUndo = 0; iUndo < i; iUndo++)
{
pReqInt = pahReqs[iUndo];
RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
pReqInt->pCtxInt = NULL;
pReqInt->AioCB.aio_sigevent.sigev_notify_kqueue = 0;
}
rc = VERR_INVALID_HANDLE;
break;
}
pReqInt->AioCB.aio_sigevent.sigev_notify_kqueue = pCtxInt->iKQueue;
pReqInt->pCtxInt = pCtxInt;
RTFILEAIOREQ_SET_STATE(pReqInt, SUBMITTED);
if (pReqInt->fFlush)
break;
cReqsSubmit++;
i++;
}
if (cReqsSubmit)
{
rcBSD = lio_listio(LIO_NOWAIT, (struct aiocb **)pahReqs, cReqsSubmit, NULL);
if (RT_UNLIKELY(rcBSD < 0))
{
if (errno == EAGAIN)
rc = VERR_FILE_AIO_INSUFFICIENT_RESSOURCES;
else
rc = RTErrConvertFromErrno(errno);
/* Check which requests got actually submitted and which not. */
for (i = 0; i < cReqs; i++)
{
pReqInt = pahReqs[i];
rcBSD = aio_error(&pReqInt->AioCB);
if ( rcBSD == -1
&& errno == EINVAL)
{
/* Was not submitted. */
RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
pReqInt->pCtxInt = NULL;
}
else if (rcBSD != EINPROGRESS)
{
/* The request encountered an error. */
RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
pReqInt->Rc = RTErrConvertFromErrno(rcBSD);
pReqInt->pCtxInt = NULL;
pReqInt->cbTransfered = 0;
}
}
break;
}
ASMAtomicAddS32(&pCtxInt->cRequests, cReqsSubmit);
cReqs -= cReqsSubmit;
pahReqs += cReqsSubmit;
}
/* Check if we have a flush request now. */
if (cReqs && RT_SUCCESS_NP(rc))
{
pReqInt = pahReqs[0];
RTFILEAIOREQ_VALID_RETURN(pReqInt);
if (pReqInt->fFlush)
{
/*
* lio_listio does not work with flush requests so
* we have to use aio_fsync directly.
*/
rcBSD = aio_fsync(O_SYNC, &pReqInt->AioCB);
if (RT_UNLIKELY(rcBSD < 0))
{
if (rcBSD == EAGAIN)
{
/* Was not submitted. */
RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
pReqInt->pCtxInt = NULL;
return VERR_FILE_AIO_INSUFFICIENT_RESSOURCES;
}
else
{
RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
pReqInt->Rc = RTErrConvertFromErrno(errno);
pReqInt->cbTransfered = 0;
return pReqInt->Rc;
}
}
ASMAtomicIncS32(&pCtxInt->cRequests);
cReqs--;
pahReqs++;
}
}
} while (cReqs);
return rc;
}
RTDECL(int) RTFileAioCtxWait(RTFILEAIOCTX hAioCtx, size_t cMinReqs, RTMSINTERVAL cMillies,
PRTFILEAIOREQ pahReqs, size_t cReqs, uint32_t *pcReqs)
{
int rc = VINF_SUCCESS;
int cRequestsCompleted = 0;
/*
* Validate the parameters, making sure to always set pcReqs.
*/
AssertPtrReturn(pcReqs, VERR_INVALID_POINTER);
*pcReqs = 0; /* always set */
PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
RTFILEAIOCTX_VALID_RETURN(pCtxInt);
AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
AssertReturn(cReqs != 0, VERR_INVALID_PARAMETER);
AssertReturn(cReqs >= cMinReqs, VERR_OUT_OF_RANGE);
if ( RT_UNLIKELY(ASMAtomicReadS32(&pCtxInt->cRequests) == 0)
&& !(pCtxInt->fFlags & RTFILEAIOCTX_FLAGS_WAIT_WITHOUT_PENDING_REQUESTS))
return VERR_FILE_AIO_NO_REQUEST;
/*
* Convert the timeout if specified.
*/
struct timespec *pTimeout = NULL;
struct timespec Timeout = {0,0};
uint64_t StartNanoTS = 0;
if (cMillies != RT_INDEFINITE_WAIT)
{
Timeout.tv_sec = cMillies / 1000;
Timeout.tv_nsec = cMillies % 1000 * 1000000;
pTimeout = &Timeout;
StartNanoTS = RTTimeNanoTS();
}
/* Wait for at least one. */
if (!cMinReqs)
cMinReqs = 1;
/* For the wakeup call. */
Assert(pCtxInt->hThreadWait == NIL_RTTHREAD);
ASMAtomicWriteHandle(&pCtxInt->hThreadWait, RTThreadSelf());
while ( cMinReqs
&& RT_SUCCESS_NP(rc))
{
struct kevent aKEvents[AIO_MAXIMUM_REQUESTS_PER_CONTEXT];
int cRequestsToWait = cMinReqs < AIO_MAXIMUM_REQUESTS_PER_CONTEXT ? cReqs : AIO_MAXIMUM_REQUESTS_PER_CONTEXT;
int rcBSD;
uint64_t StartTime;
ASMAtomicXchgBool(&pCtxInt->fWaiting, true);
rcBSD = kevent(pCtxInt->iKQueue, NULL, 0, aKEvents, cRequestsToWait, pTimeout);
ASMAtomicXchgBool(&pCtxInt->fWaiting, false);
if (RT_UNLIKELY(rcBSD < 0))
{
rc = RTErrConvertFromErrno(errno);
break;
}
uint32_t const cDone = rcBSD;
/* Process received events. */
for (uint32_t i = 0; i < cDone; i++)
{
PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)aKEvents[i].udata;
AssertPtr(pReqInt);
Assert(pReqInt->u32Magic == RTFILEAIOREQ_MAGIC);
/*
* Retrieve the status code here already because the
* user may omit the RTFileAioReqGetRC() call and
* we will leak kernel resources then.
* This will result in errors during submission
* of other requests as soon as the max_aio_queue_per_proc
* limit is reached.
*/
int cbTransfered = aio_return(&pReqInt->AioCB);
if (cbTransfered < 0)
{
pReqInt->Rc = RTErrConvertFromErrno(cbTransfered);
pReqInt->cbTransfered = 0;
}
else
{
pReqInt->Rc = VINF_SUCCESS;
pReqInt->cbTransfered = cbTransfered;
}
RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
pahReqs[cRequestsCompleted++] = (RTFILEAIOREQ)pReqInt;
}
/*
* Done Yet? If not advance and try again.
*/
if (cDone >= cMinReqs)
break;
cMinReqs -= cDone;
cReqs -= cDone;
if (cMillies != RT_INDEFINITE_WAIT)
{
/* The API doesn't return ETIMEDOUT, so we have to fix that ourselves. */
uint64_t NanoTS = RTTimeNanoTS();
uint64_t cMilliesElapsed = (NanoTS - StartNanoTS) / 1000000;
if (cMilliesElapsed >= cMillies)
{
rc = VERR_TIMEOUT;
break;
}
/* The syscall supposedly updates it, but we're paranoid. :-) */
Timeout.tv_sec = (cMillies - (RTMSINTERVAL)cMilliesElapsed) / 1000;
Timeout.tv_nsec = (cMillies - (RTMSINTERVAL)cMilliesElapsed) % 1000 * 1000000;
}
}
/*
* Update the context state and set the return value.
*/
*pcReqs = cRequestsCompleted;
ASMAtomicSubS32(&pCtxInt->cRequests, cRequestsCompleted);
Assert(pCtxInt->hThreadWait == RTThreadSelf());
ASMAtomicWriteHandle(&pCtxInt->hThreadWait, NIL_RTTHREAD);
/*
* Clear the wakeup flag and set rc.
*/
if ( pCtxInt->fWokenUp
&& RT_SUCCESS(rc))
{
ASMAtomicXchgBool(&pCtxInt->fWokenUp, false);
rc = VERR_INTERRUPTED;
}
return rc;
}
RTDECL(int) RTFileAioCtxWakeup(RTFILEAIOCTX hAioCtx)
{
PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
RTFILEAIOCTX_VALID_RETURN(pCtxInt);
/** @todo r=bird: Define the protocol for how to resume work after calling
* this function. */
bool fWokenUp = ASMAtomicXchgBool(&pCtxInt->fWokenUp, true);
/*
* Read the thread handle before the status flag.
* If we read the handle after the flag we might
* end up with an invalid handle because the thread
* waiting in RTFileAioCtxWakeup() might get scheduled
* before we read the flag and returns.
* We can ensure that the handle is valid if fWaiting is true
* when reading the handle before the status flag.
*/
RTTHREAD hThread;
ASMAtomicReadHandle(&pCtxInt->hThreadWait, &hThread);
bool fWaiting = ASMAtomicReadBool(&pCtxInt->fWaiting);
if ( !fWokenUp
&& fWaiting)
{
/*
* If a thread waits the handle must be valid.
* It is possible that the thread returns from
* kevent() before the signal is send.
* This is no problem because we already set fWokenUp
* to true which will let the thread return VERR_INTERRUPTED
* and the next call to RTFileAioCtxWait() will not
* return VERR_INTERRUPTED because signals are not saved
* and will simply vanish if the destination thread can't
* receive it.
*/
Assert(hThread != NIL_RTTHREAD);
RTThreadPoke(hThread);
}
return VINF_SUCCESS;
}