Adding upstream version 6.0.4-dfsg.upstream/6.0.4-dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 838 insertions, 0 deletions

diff --git a/src/VBox/Runtime/r3/linux/fileaio-linux.cpp b/src/VBox/Runtime/r3/linux/fileaio-linux.cpp
new file mode 100644
index 00000000..9df7f96c
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/fileaio-linux.cpp
@@ -0,0 +1,838 @@
+/* $Id: fileaio-linux.cpp $ */
+/** @file
+ * IPRT - File async I/O, native implementation for the Linux host platform.
+ */
+
+/*
+ * Copyright (C) 2006-2019 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.
+ */
+
+/** @page pg_rtfileaio_linux     RTFile Async I/O - Linux Implementation Notes
+ * @internal
+ *
+ * Linux implements the kernel async I/O API through the io_* syscalls. They are
+ * not exposed in the glibc (the aio_* API uses userspace threads and blocking
+ * I/O operations to simulate async behavior). There is an external library
+ * called libaio which implements these syscalls but because we don't want to
+ * have another dependency and this library is not installed by default and the
+ * interface is really simple we use the kernel interface directly using wrapper
+ * functions.
+ *
+ * The interface has some limitations. The first one is that the file must be
+ * opened with O_DIRECT. This disables caching done by the kernel which can be
+ * compensated if the user of this API implements caching itself. The next
+ * limitation is that data buffers must be aligned at a 512 byte boundary or the
+ * request will fail.
+ */
+/** @todo r=bird: What's this about "must be opened with O_DIRECT"? An
+ *        explanation would be nice, esp. seeing what Linus is quoted saying
+ *        about it in the open man page... */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include <iprt/asm.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 <unistd.h>
+#include <sys/syscall.h>
+#include <errno.h>
+
+#include <iprt/file.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** The async I/O context handle */
+typedef unsigned long LNXKAIOCONTEXT;
+
+/**
+ * Supported commands for the iocbs
+ */
+enum
+{
+    LNXKAIO_IOCB_CMD_READ   = 0,
+    LNXKAIO_IOCB_CMD_WRITE  = 1,
+    LNXKAIO_IOCB_CMD_FSYNC  = 2,
+    LNXKAIO_IOCB_CMD_FDSYNC = 3
+};
+
+/**
+ * The iocb structure of a request which is passed to the kernel.
+ *
+ * We redefined this here because the version in the header lacks padding
+ * for 32bit.
+ */
+typedef struct LNXKAIOIOCB
+{
+    /** Opaque pointer to data which is returned on an I/O event. */
+    void     *pvUser;
+#ifdef RT_ARCH_X86
+    uint32_t  u32Padding0;
+#endif
+    /** Contains the request number and is set by the kernel. */
+    uint32_t  u32Key;
+    /** Reserved. */
+    uint32_t  u32Reserved0;
+    /** The I/O opcode. */
+    uint16_t  u16IoOpCode;
+    /** Request priority. */
+    int16_t   i16Priority;
+    /** The file descriptor. */
+    uint32_t  uFileDesc;
+    /** The userspace pointer to the buffer containing/receiving the data. */
+    void     *pvBuf;
+#ifdef RT_ARCH_X86
+    uint32_t  u32Padding1;
+#endif
+    /** How many bytes to transfer. */
+#ifdef RT_ARCH_X86
+    uint32_t  cbTransfer;
+    uint32_t  u32Padding2;
+#elif defined(RT_ARCH_AMD64)
+    uint64_t  cbTransfer;
+#else
+# error "Unknown architecture"
+#endif
+    /** At which offset to start the transfer. */
+    int64_t   off;
+    /** Reserved. */
+    uint64_t  u64Reserved1;
+    /** Flags */
+    uint32_t  fFlags;
+    /** Readyness signal file descriptor. */
+    uint32_t  u32ResFd;
+} LNXKAIOIOCB, *PLNXKAIOIOCB;
+
+/**
+ * I/O event structure to notify about completed requests.
+ * Redefined here too because of the padding.
+ */
+typedef struct LNXKAIOIOEVENT
+{
+    /** The pvUser field from the iocb. */
+    void         *pvUser;
+#ifdef RT_ARCH_X86
+    uint32_t      u32Padding0;
+#endif
+    /** The LNXKAIOIOCB object this event is for. */
+    PLNXKAIOIOCB *pIoCB;
+#ifdef RT_ARCH_X86
+    uint32_t      u32Padding1;
+#endif
+    /** The result code of the operation .*/
+#ifdef RT_ARCH_X86
+    int32_t       rc;
+    uint32_t      u32Padding2;
+#elif defined(RT_ARCH_AMD64)
+    int64_t       rc;
+#else
+# error "Unknown architecture"
+#endif
+    /** Secondary result code. */
+#ifdef RT_ARCH_X86
+    int32_t       rc2;
+    uint32_t      u32Padding3;
+#elif defined(RT_ARCH_AMD64)
+    int64_t       rc2;
+#else
+# error "Unknown architecture"
+#endif
+} LNXKAIOIOEVENT, *PLNXKAIOIOEVENT;
+
+
+/**
+ * Async I/O completion context state.
+ */
+typedef struct RTFILEAIOCTXINTERNAL
+{
+    /** Handle to the async I/O context. */
+    LNXKAIOCONTEXT      AioContext;
+    /** Maximum number of requests this context can handle. */
+    int                 cRequestsMax;
+    /** 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. This must be the FIRST elment in
+     *  the structure! (see notes below) */
+    LNXKAIOIOCB           AioCB;
+    /** Current state the request is in. */
+    RTFILEAIOREQSTATE     enmState;
+    /** The I/O context this request is associated with. */
+    LNXKAIOCONTEXT        AioContext;
+    /** Return code the request completed with. */
+    int                   Rc;
+    /** Number of bytes actually transferred. */
+    size_t                cbTransfered;
+    /** Completion context we are assigned to. */
+    PRTFILEAIOCTXINTERNAL pCtxInt;
+    /** 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
+
+
+/**
+ * Creates a new async I/O context.
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxCreate(unsigned cEvents, LNXKAIOCONTEXT *pAioContext)
+{
+    int rc = syscall(__NR_io_setup, cEvents, pAioContext);
+    if (RT_UNLIKELY(rc == -1))
+    {
+        if (errno == EAGAIN)
+            return VERR_FILE_AIO_INSUFFICIENT_EVENTS;
+        else
+            return RTErrConvertFromErrno(errno);
+    }
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Destroys a async I/O context.
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxDestroy(LNXKAIOCONTEXT AioContext)
+{
+    int rc = syscall(__NR_io_destroy, AioContext);
+    if (RT_UNLIKELY(rc == -1))
+        return RTErrConvertFromErrno(errno);
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Submits an array of I/O requests to the kernel.
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxSubmit(LNXKAIOCONTEXT AioContext, long cReqs, LNXKAIOIOCB **ppIoCB, int *pcSubmitted)
+{
+    int rc = syscall(__NR_io_submit, AioContext, cReqs, ppIoCB);
+    if (RT_UNLIKELY(rc == -1))
+        return RTErrConvertFromErrno(errno);
+
+    *pcSubmitted = rc;
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Cancels a I/O request.
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxCancel(LNXKAIOCONTEXT AioContext, PLNXKAIOIOCB pIoCB, PLNXKAIOIOEVENT pIoResult)
+{
+    int rc = syscall(__NR_io_cancel, AioContext, pIoCB, pIoResult);
+    if (RT_UNLIKELY(rc == -1))
+        return RTErrConvertFromErrno(errno);
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Waits for I/O events.
+ * @returns Number of events (natural number w/ 0), IPRT error code (negative).
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxGetEvents(LNXKAIOCONTEXT AioContext, long cReqsMin, long cReqs,
+                                            PLNXKAIOIOEVENT paIoResults, struct timespec *pTimeout)
+{
+    int rc = syscall(__NR_io_getevents, AioContext, cReqsMin, cReqs, paIoResults, pTimeout);
+    if (RT_UNLIKELY(rc == -1))
+        return RTErrConvertFromErrno(errno);
+
+    return rc;
+}
+
+RTR3DECL(int) RTFileAioGetLimits(PRTFILEAIOLIMITS pAioLimits)
+{
+    int rc = VINF_SUCCESS;
+    AssertPtrReturn(pAioLimits, VERR_INVALID_POINTER);
+
+    /*
+     * Check if the API is implemented by creating a
+     * completion port.
+     */
+    LNXKAIOCONTEXT AioContext = 0;
+    rc = rtFileAsyncIoLinuxCreate(1, &AioContext);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    rc = rtFileAsyncIoLinuxDestroy(AioContext);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /* Supported - fill in the limits. The alignment is the only restriction. */
+    pAioLimits->cReqsOutstandingMax = RTFILEAIO_UNLIMITED_REQS;
+    pAioLimits->cbBufferAlignment   = 512;
+
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTFileAioReqCreate(PRTFILEAIOREQ phReq)
+{
+    AssertPtrReturn(phReq, VERR_INVALID_POINTER);
+
+    /*
+     * Allocate a new request and initialize it.
+     */
+    PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)RTMemAllocZ(sizeof(*pReqInt));
+    if (RT_UNLIKELY(!pReqInt))
+        return VERR_NO_MEMORY;
+
+    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,
+                                            uint16_t 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);
+
+    if (uTransferDirection != LNXKAIO_IOCB_CMD_FSYNC)
+    {
+        AssertPtr(pvBuf);
+        Assert(off >= 0);
+        Assert(cbTransfer > 0);
+    }
+
+    /*
+     * Setup the control block and clear the finished flag.
+     */
+    pReqInt->AioCB.u16IoOpCode = uTransferDirection;
+    pReqInt->AioCB.uFileDesc   = RTFileToNative(hFile);
+    pReqInt->AioCB.off         = off;
+    pReqInt->AioCB.cbTransfer  = cbTransfer;
+    pReqInt->AioCB.pvBuf       = pvBuf;
+    pReqInt->AioCB.pvUser      = pvUser;
+
+    pReqInt->pCtxInt           = NULL;
+    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, LNXKAIO_IOCB_CMD_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, LNXKAIO_IOCB_CMD_WRITE,
+                                       off, (void *)pvBuf, cbWrite, pvUser);
+}
+
+
+RTDECL(int) RTFileAioReqPrepareFlush(RTFILEAIOREQ hReq, RTFILE hFile, void *pvUser)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    AssertReturn(hFile != NIL_RTFILE, VERR_INVALID_HANDLE);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+
+    return rtFileAioReqPrepareTransfer(pReqInt, hFile, LNXKAIO_IOCB_CMD_FSYNC,
+                                       0, NULL, 0, pvUser);
+}
+
+
+RTDECL(void *) RTFileAioReqGetUser(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN_RC(pReqInt, NULL);
+
+    return pReqInt->AioCB.pvUser;
+}
+
+
+RTDECL(int) RTFileAioReqCancel(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_NOT_SUBMITTED);
+
+    LNXKAIOIOEVENT AioEvent;
+    int rc = rtFileAsyncIoLinuxCancel(pReqInt->AioContext, &pReqInt->AioCB, &AioEvent);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * 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;
+    }
+    if (rc == VERR_TRY_AGAIN)
+        return VERR_FILE_AIO_IN_PROGRESS;
+    return rc;
+}
+
+
+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 (    pcbTransfered
+        &&  RT_SUCCESS(pReqInt->Rc))
+        *pcbTransfered = pReqInt->cbTransfered;
+
+    return pReqInt->Rc;
+}
+
+
+RTDECL(int) RTFileAioCtxCreate(PRTFILEAIOCTX phAioCtx, uint32_t cAioReqsMax,
+                               uint32_t fFlags)
+{
+    PRTFILEAIOCTXINTERNAL pCtxInt;
+    AssertPtrReturn(phAioCtx, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTFILEAIOCTX_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /* The kernel interface needs a maximum. */
+    if (cAioReqsMax == RTFILEAIO_UNLIMITED_REQS)
+        return VERR_OUT_OF_RANGE;
+
+    pCtxInt = (PRTFILEAIOCTXINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOCTXINTERNAL));
+    if (RT_UNLIKELY(!pCtxInt))
+        return VERR_NO_MEMORY;
+
+    /* Init the event handle. */
+    int rc = rtFileAsyncIoLinuxCreate(cAioReqsMax, &pCtxInt->AioContext);
+    if (RT_SUCCESS(rc))
+    {
+        pCtxInt->fWokenUp     = false;
+        pCtxInt->fWaiting     = false;
+        pCtxInt->hThreadWait  = NIL_RTTHREAD;
+        pCtxInt->cRequestsMax = cAioReqsMax;
+        pCtxInt->fFlags       = fFlags;
+        pCtxInt->u32Magic     = RTFILEAIOCTX_MAGIC;
+        *phAioCtx = (RTFILEAIOCTX)pCtxInt;
+    }
+    else
+        RTMemFree(pCtxInt);
+
+    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;
+
+    /* The native bit first, then mark it as dead and free it. */
+    int rc = rtFileAsyncIoLinuxDestroy(pCtxInt->AioContext);
+    if (RT_FAILURE(rc))
+        return rc;
+    ASMAtomicUoWriteU32(&pCtxInt->u32Magic, RTFILEAIOCTX_MAGIC_DEAD);
+    RTMemFree(pCtxInt);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(uint32_t) RTFileAioCtxGetMaxReqCount(RTFILEAIOCTX hAioCtx)
+{
+    /* Nil means global here. */
+    if (hAioCtx == NIL_RTFILEAIOCTX)
+        return RTFILEAIO_UNLIMITED_REQS; /** @todo r=bird: I'm a bit puzzled by this return value since it
+                                          *                is completely useless in RTFileAioCtxCreate. */
+
+    /* Return 0 if the handle is invalid, it's better than garbage I think... */
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN_RC(pCtxInt, 0);
+
+    return pCtxInt->cRequestsMax;
+}
+
+RTDECL(int) RTFileAioCtxAssociateWithFile(RTFILEAIOCTX hAioCtx, RTFILE hFile)
+{
+    /* Nothing to do. */
+    NOREF(hAioCtx); NOREF(hFile);
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioCtxSubmit(RTFILEAIOCTX hAioCtx, PRTFILEAIOREQ pahReqs, size_t cReqs)
+{
+    int rc = VINF_SUCCESS;
+
+    /*
+     * Parameter validation.
+     */
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+    AssertReturn(cReqs > 0,  VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+    uint32_t i = cReqs;
+    PRTFILEAIOREQINTERNAL pReqInt = NULL;
+
+    /*
+     * Validate requests and associate with the context.
+     */
+    while (i-- > 0)
+    {
+        pReqInt = pahReqs[i];
+        if (RTFILEAIOREQ_IS_NOT_VALID(pReqInt))
+        {
+            /* Undo everything and stop submitting. */
+            size_t iUndo = cReqs;
+            while (iUndo-- > i)
+            {
+                pReqInt = pahReqs[iUndo];
+                RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                pReqInt->pCtxInt = NULL;
+            }
+            return VERR_INVALID_HANDLE;
+        }
+
+        pReqInt->AioContext = pCtxInt->AioContext;
+        pReqInt->pCtxInt    = pCtxInt;
+        RTFILEAIOREQ_SET_STATE(pReqInt, SUBMITTED);
+    }
+
+    do
+    {
+        /*
+         * We cast pahReqs to the Linux iocb structure to avoid copying the requests
+         * into a temporary array. This is possible because the iocb structure is
+         * the first element in the request structure (see PRTFILEAIOCTXINTERNAL).
+         */
+        int cReqsSubmitted = 0;
+        rc = rtFileAsyncIoLinuxSubmit(pCtxInt->AioContext, cReqs,
+                                      (PLNXKAIOIOCB *)pahReqs,
+                                      &cReqsSubmitted);
+        if (RT_FAILURE(rc))
+        {
+            /*
+             * We encountered an error.
+             * This means that the first IoCB
+             * is not correctly initialized
+             * (invalid buffer alignment or bad file descriptor).
+             * Revert every request into the prepared state except
+             * the first one which will switch to completed.
+             * Another reason could be insufficient resources.
+             */
+            i = cReqs;
+            while (i-- > 0)
+            {
+                /* Already validated. */
+                pReqInt = pahReqs[i];
+                pReqInt->pCtxInt    = NULL;
+                pReqInt->AioContext = 0;
+                RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+            }
+
+            if (rc == VERR_TRY_AGAIN)
+                return VERR_FILE_AIO_INSUFFICIENT_RESSOURCES;
+            else
+            {
+                /* The first request failed. */
+                pReqInt = pahReqs[0];
+                RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+                pReqInt->Rc = rc;
+                pReqInt->cbTransfered = 0;
+                return rc;
+            }
+        }
+
+        /* Advance. */
+        cReqs   -= cReqsSubmitted;
+        pahReqs += cReqsSubmitted;
+        ASMAtomicAddS32(&pCtxInt->cRequests, cReqsSubmitted);
+
+    } while (cReqs);
+
+    return rc;
+}
+
+
+RTDECL(int) RTFileAioCtxWait(RTFILEAIOCTX hAioCtx, size_t cMinReqs, RTMSINTERVAL cMillies,
+                             PRTFILEAIOREQ pahReqs, size_t cReqs, uint32_t *pcReqs)
+{
+    /*
+     * 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);
+
+    /*
+     * Can't wait if there are not requests around.
+     */
+    if (   RT_UNLIKELY(ASMAtomicUoReadS32(&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());
+
+    /*
+     * Loop until we're woken up, hit an error (incl timeout), or
+     * have collected the desired number of requests.
+     */
+    int rc = VINF_SUCCESS;
+    int cRequestsCompleted = 0;
+    while (!pCtxInt->fWokenUp)
+    {
+        LNXKAIOIOEVENT  aPortEvents[AIO_MAXIMUM_REQUESTS_PER_CONTEXT];
+        int             cRequestsToWait = RT_MIN(cReqs, AIO_MAXIMUM_REQUESTS_PER_CONTEXT);
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, true);
+        rc = rtFileAsyncIoLinuxGetEvents(pCtxInt->AioContext, cMinReqs, cRequestsToWait, &aPortEvents[0], pTimeout);
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, false);
+        if (RT_FAILURE(rc))
+            break;
+        uint32_t const cDone = rc;
+        rc = VINF_SUCCESS;
+
+        /*
+         * Process received events / requests.
+         */
+        for (uint32_t i = 0; i < cDone; i++)
+        {
+            /*
+             * The iocb is the first element in our request structure.
+             * So we can safely cast it directly to the handle (see above)
+             */
+            PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)aPortEvents[i].pIoCB;
+            AssertPtr(pReqInt);
+            Assert(pReqInt->u32Magic == RTFILEAIOREQ_MAGIC);
+
+            /** @todo aeichner: The rc field contains the result code
+             *  like you can find in errno for the normal read/write ops.
+             *  But there is a second field called rc2. I don't know the
+             *  purpose for it yet.
+             */
+            if (RT_UNLIKELY(aPortEvents[i].rc < 0))
+                pReqInt->Rc = RTErrConvertFromErrno(-aPortEvents[i].rc); /* Convert to positive value. */
+            else
+            {
+                pReqInt->Rc = VINF_SUCCESS;
+                pReqInt->cbTransfered = aPortEvents[i].rc;
+            }
+
+            /* Mark the request as finished. */
+            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
+         * rtFileAsyncIoLinuxGetEvents() 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;
+}
+