Storage/testcase/VDIoBackendMem.cpp

078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync/** $Id$ */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync/** @file
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync *
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * VBox HDD container test utility, async I/O memory backend
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync/*
c7814cf6e1240a519cbec0441e033d0e2470ed00vboxsync * Copyright (C) 2011-2012 Oracle Corporation
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync *
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * This file is part of VirtualBox Open Source Edition (OSE), as
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * available from http://www.virtualbox.org. This file is free software;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * you can redistribute it and/or modify it under the terms of the GNU
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * General Public License (GPL) as published by the Free Software
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * Foundation, in version 2 as it comes in the "COPYING" file of the
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#define LOGGROUP LOGGROUP_DEFAULT /** @todo: Log group */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include <iprt/err.h>
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include <iprt/log.h>
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include <iprt/assert.h>
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include <iprt/asm.h>
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include <iprt/mem.h>
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include <iprt/thread.h>
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include <iprt/circbuf.h>
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include <iprt/semaphore.h>
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include "VDMemDisk.h"
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#include "VDIoBackendMem.h"
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync#define VDMEMIOBACKEND_REQS 1024
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync/**
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * Memory I/O request.
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsynctypedef struct VDIOBACKENDREQ
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync{
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** I/O request direction. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    VDIOTXDIR       enmTxDir;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** Memory disk handle. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    PVDMEMDISK      pMemDisk;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** Start offset. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    uint64_t        off;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** Size of the transfer. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    size_t          cbTransfer;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** Completion handler to call. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    PFNVDIOCOMPLETE pfnComplete;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** Opaque user data. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    void           *pvUser;
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync    /** S/G buffer. */
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync    RTSGBUF         SgBuf;
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync    /** Segment array - variable size. */
39cac49f62afd27b0ffdbb779c7c64211939030cvboxsync    RTSGSEG         aSegs[1];
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync} VDIOBACKENDREQ, *PVDIOBACKENDREQ;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsynctypedef PVDIOBACKENDREQ *PPVDIOBACKENDREQ;
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync/**
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * I/O memory backend
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsynctypedef struct VDIOBACKENDMEM
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync{
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** Thread handle for the backend. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    RTTHREAD    hThreadIo;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** Circular buffer used for submitting requests. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    PRTCIRCBUF  pRequestRing;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** Size of the buffer in request items. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    unsigned    cReqsRing;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    /** Event semaphore the thread waits on for more work. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    RTSEMEVENT  EventSem;
4bfa7b58e362a1bca0628643c352c137900bf01avboxsync    /** Flag whether the server should be still running. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    volatile bool fRunning;
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    /** Number of requests waiting in the request buffer. */
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    volatile uint32_t cReqsWaiting;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync} VDIOBACKENDMEM;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsyncstatic int vdIoBackendMemThread(RTTHREAD hThread, void *pvUser);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync/**
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * Pokes the I/O thread that something interesting happened.
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync *
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * @returns IPRT status code.
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync *
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * @param pIoBackend    The backend to poke.
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsyncstatic int vdIoBackendMemThreadPoke(PVDIOBACKENDMEM pIoBackend)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync{
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    return RTSemEventSignal(pIoBackend->EventSem);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync}
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsyncint VDIoBackendMemCreate(PPVDIOBACKENDMEM ppIoBackend)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync{
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    int rc = VINF_SUCCESS;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    PVDIOBACKENDMEM pIoBackend = NULL;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    pIoBackend = (PVDIOBACKENDMEM)RTMemAllocZ(sizeof(VDIOBACKENDMEM));
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    if (pIoBackend)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    {
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync        rc = RTCircBufCreate(&pIoBackend->pRequestRing, VDMEMIOBACKEND_REQS * sizeof(PVDIOBACKENDREQ));
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        if (RT_SUCCESS(rc))
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        {
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            pIoBackend->cReqsRing = VDMEMIOBACKEND_REQS * sizeof(VDIOBACKENDREQ);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            pIoBackend->fRunning  = true;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            rc = RTSemEventCreate(&pIoBackend->EventSem);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            if (RT_SUCCESS(rc))
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            {
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                rc = RTThreadCreate(&pIoBackend->hThreadIo, vdIoBackendMemThread, pIoBackend, 0, RTTHREADTYPE_IO,
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                                    RTTHREADFLAGS_WAITABLE, "MemIo");
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                if (RT_SUCCESS(rc))
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                {
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                    *ppIoBackend = pIoBackend;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                    LogFlowFunc(("returns success\n"));
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                    return VINF_SUCCESS;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                }
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                RTSemEventDestroy(pIoBackend->EventSem);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            }
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            RTCircBufDestroy(pIoBackend->pRequestRing);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        }
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        RTMemFree(pIoBackend);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    }
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    else
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        rc = VERR_NO_MEMORY;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    return rc;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync}
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsyncint VDIoBackendMemDestroy(PVDIOBACKENDMEM pIoBackend)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync{
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    ASMAtomicXchgBool(&pIoBackend->fRunning, false);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    vdIoBackendMemThreadPoke(pIoBackend);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    RTThreadWait(pIoBackend->hThreadIo, RT_INDEFINITE_WAIT, NULL);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    RTSemEventDestroy(pIoBackend->EventSem);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    RTCircBufDestroy(pIoBackend->pRequestRing);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    RTMemFree(pIoBackend);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    return VINF_SUCCESS;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync}
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsyncint VDIoBackendMemTransfer(PVDIOBACKENDMEM pIoBackend, PVDMEMDISK pMemDisk,
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync                           VDIOTXDIR enmTxDir, uint64_t off, size_t cbTransfer,
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync                           PRTSGBUF pSgBuf, PFNVDIOCOMPLETE pfnComplete, void *pvUser)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync{
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    PVDIOBACKENDREQ pReq = NULL;
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    PPVDIOBACKENDREQ ppReq = NULL;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    size_t cbData;
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync    unsigned cSegs = 0;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    LogFlowFunc(("Queuing request\n"));
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync    if (enmTxDir != VDIOTXDIR_FLUSH)
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync        RTSgBufSegArrayCreate(pSgBuf, NULL, &cSegs, cbTransfer);
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    pReq = (PVDIOBACKENDREQ)RTMemAlloc(RT_OFFSETOF(VDIOBACKENDREQ, aSegs[cSegs]));
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    if (!pReq)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        return VERR_NO_MEMORY;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    RTCircBufAcquireWriteBlock(pIoBackend->pRequestRing, sizeof(PVDIOBACKENDREQ), (void **)&ppReq, &cbData);
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    if (!pReq)
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    {
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync        RTMemFree(pReq);
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync        return VERR_NO_MEMORY;
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    }
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    Assert(cbData == sizeof(PVDIOBACKENDREQ));
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    pReq->enmTxDir    = enmTxDir;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    pReq->cbTransfer  = cbTransfer;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    pReq->off         = off;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    pReq->pMemDisk    = pMemDisk;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    pReq->pfnComplete = pfnComplete;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    pReq->pvUser      = pvUser;
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync    if (enmTxDir != VDIOTXDIR_FLUSH)
39cac49f62afd27b0ffdbb779c7c64211939030cvboxsync    {
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync        RTSgBufSegArrayCreate(pSgBuf, &pReq->aSegs[0], &cSegs, cbTransfer);
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync        RTSgBufInit(&pReq->SgBuf, pReq->aSegs, cSegs);
39cac49f62afd27b0ffdbb779c7c64211939030cvboxsync    }
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    *ppReq = pReq;
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    RTCircBufReleaseWriteBlock(pIoBackend->pRequestRing, sizeof(PVDIOBACKENDREQ));
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    uint32_t cReqsWaiting = ASMAtomicIncU32(&pIoBackend->cReqsWaiting);
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync    if (cReqsWaiting == 1)
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync        vdIoBackendMemThreadPoke(pIoBackend);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    return VINF_SUCCESS;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync}
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync/**
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * I/O thread for the memory backend.
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync *
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * @returns IPRT status code.
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync *
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * @param hThread    The thread handle.
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync * @param pvUser     Opaque user data.
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsyncstatic int vdIoBackendMemThread(RTTHREAD hThread, void *pvUser)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync{
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    PVDIOBACKENDMEM pIoBackend = (PVDIOBACKENDMEM)pvUser;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    while (pIoBackend->fRunning)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    {
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        int rc = RTSemEventWait(pIoBackend->EventSem, RT_INDEFINITE_WAIT);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        if (RT_FAILURE(rc) || !pIoBackend->fRunning)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            break;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        PVDIOBACKENDREQ pReq;
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync        PPVDIOBACKENDREQ ppReq;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        size_t cbData;
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync        uint32_t cReqsWaiting = ASMAtomicXchgU32(&pIoBackend->cReqsWaiting, 0);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync        while (cReqsWaiting)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        {
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            int rcReq = VINF_SUCCESS;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync            /* Do we have another request? */
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync            RTCircBufAcquireReadBlock(pIoBackend->pRequestRing, sizeof(PVDIOBACKENDREQ), (void **)&ppReq, &cbData);
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync            Assert(!ppReq || cbData == sizeof(PVDIOBACKENDREQ));
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync            RTCircBufReleaseReadBlock(pIoBackend->pRequestRing, cbData);
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync            pReq = *ppReq;
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync            cReqsWaiting--;
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync            LogFlowFunc(("Processing request\n"));
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            switch (pReq->enmTxDir)
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            {
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                case VDIOTXDIR_READ:
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                {
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync                    rcReq = VDMemDiskRead(pReq->pMemDisk, pReq->off, pReq->cbTransfer, &pReq->SgBuf);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                    break;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                }
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                case VDIOTXDIR_WRITE:
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                {
14a9673ef19f6d8d49f83050d86cb444a55d4008vboxsync                    rcReq = VDMemDiskWrite(pReq->pMemDisk, pReq->off, pReq->cbTransfer, &pReq->SgBuf);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                    break;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                }
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                case VDIOTXDIR_FLUSH:
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                    break;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                default:
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync                    AssertMsgFailed(("Invalid TX direction!\n"));
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            }
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            /* Notify completion. */
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync            pReq->pfnComplete(pReq->pvUser, rcReq);
d82d7a8b44b27420e50f410d8ee5b990bb8b8f12vboxsync            RTMemFree(pReq);
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync        }
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    }
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync    return VINF_SUCCESS;
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync}
078c5b8c5c814755aab943bf62cadef7e91c419cvboxsync