Leaked source code of windows server 2003
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/*++
Copyright (c) 1996 Microsoft Corporation
Module Name:
pingpong.c
Abstract
Interrupt style collections like to always have a read pending in case
something happens. This file contains routines to keep IRPs down
in the miniport, and to complete client reads (if a client read IRP is
pending) or queue them (if not).
Author:
Ervin P.
Environment:
Kernel mode only
Revision History:
--*/
#include "pch.h"
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, HidpInitializePingPongIrps)
#pragma alloc_text(PAGE, HidpReallocPingPongIrps)
#endif
/*
********************************************************************************
* HidpInitializePingPongIrps
********************************************************************************
*
*
*/
NTSTATUS HidpInitializePingPongIrps(FDO_EXTENSION *fdoExtension)
{
NTSTATUS result = STATUS_SUCCESS;
ULONG i;
CCHAR numIrpStackLocations;
PAGED_CODE();
/*
* Note that our functional device object normally requires FDO->StackSize stack
* locations; but these IRPs will only be sent to the minidriver, so we need one less.
*
* THIS MEANS THAT WE SHOULD NEVER TOUCH OUR OWN STACK LOCATION (we don't have one!)
*/
numIrpStackLocations = fdoExtension->fdo->StackSize - 1;
//
// Next determine the size of each input HID report. There
// must be at least one collection of type interrupt, or we wouldn't
// need the ping-pong stuff at all and therefore wouldn't be here.
//
ASSERT(fdoExtension->maxReportSize > 0);
ASSERT(fdoExtension->numPingPongs > 0);
fdoExtension->pingPongs = ALLOCATEPOOL(NonPagedPool, fdoExtension->numPingPongs*sizeof(HIDCLASS_PINGPONG));
if (fdoExtension->pingPongs){
ULONG reportBufferSize = fdoExtension->maxReportSize;
RtlZeroMemory(fdoExtension->pingPongs, fdoExtension->numPingPongs*sizeof(HIDCLASS_PINGPONG));
#if DBG
// reserve space for guard word
reportBufferSize += sizeof(ULONG);
#endif
for (i = 0; i < fdoExtension->numPingPongs; i++){
fdoExtension->pingPongs[i].myFdoExt = fdoExtension;
fdoExtension->pingPongs[i].weAreCancelling = 0;
fdoExtension->pingPongs[i].sig = PINGPONG_SIG;
/*
* Initialize backoff timeout to 1 second (in neg 100-nsec units)
*/
fdoExtension->pingPongs[i].backoffTimerPeriod.HighPart = -1;
fdoExtension->pingPongs[i].backoffTimerPeriod.LowPart = -10000000;
KeInitializeTimer(&fdoExtension->pingPongs[i].backoffTimer);
KeInitializeDpc(&fdoExtension->pingPongs[i].backoffTimerDPC,
HidpPingpongBackoffTimerDpc,
&fdoExtension->pingPongs[i]);
fdoExtension->pingPongs[i].reportBuffer = ALLOCATEPOOL(NonPagedPool, reportBufferSize);
if (fdoExtension->pingPongs[i].reportBuffer){
PIRP irp;
#if DBG
#ifdef _X86_
// this sets off alignment problems on Alpha
// place guard word
*(PULONG)(&fdoExtension->pingPongs[i].reportBuffer[fdoExtension->maxReportSize]) = HIDCLASS_REPORT_BUFFER_GUARD;
#endif
#endif
irp = IoAllocateIrp(numIrpStackLocations, FALSE);
if (irp){
/*
* Point the ping-pong IRP's UserBuffer to the corresponding
* ping-pong object's report buffer.
*/
irp->UserBuffer = fdoExtension->pingPongs[i].reportBuffer;
fdoExtension->pingPongs[i].irp = irp;
KeInitializeEvent(&fdoExtension->pingPongs[i].sentEvent,
NotificationEvent,
TRUE); // Set to signaled
KeInitializeEvent(&fdoExtension->pingPongs[i].pumpDoneEvent,
NotificationEvent,
TRUE); // Set to signaled
}
else {
result = STATUS_INSUFFICIENT_RESOURCES;
break;
}
}
else {
result = STATUS_INSUFFICIENT_RESOURCES;
break;
}
}
}
else {
result = STATUS_INSUFFICIENT_RESOURCES;
}
DBGSUCCESS(result, TRUE)
return result;
}
/*
********************************************************************************
* HidpReallocPingPongIrps
********************************************************************************
*
*
*/
NTSTATUS HidpReallocPingPongIrps(FDO_EXTENSION *fdoExtension, ULONG newNumBufs)
{
NTSTATUS status = STATUS_SUCCESS;
PAGED_CODE();
if (fdoExtension->driverExt->DevicesArePolled){
/*
* Polled devices don't _HAVE_ ping-pong IRPs.
*/
DBGERR(("Minidriver devices polled fdo %x.", fdoExtension))
fdoExtension->numPingPongs = 0;
fdoExtension->pingPongs = BAD_POINTER;
status = STATUS_SUCCESS;
}
else if (newNumBufs < MIN_PINGPONG_IRPS){
DBGERR(("newNumBufs < MIN_PINGPONG_IRPS!"))
status = STATUS_INVALID_DEVICE_REQUEST;
}
else {
DestroyPingPongs(fdoExtension);
if (HidpSetMaxReportSize(fdoExtension)){
/*
* Initialize and restart the new ping-pong IRPs.
* If we can't allocate the desired number of buffers,
* keep reducing until we get some.
*/
do {
fdoExtension->numPingPongs = newNumBufs;
status = HidpInitializePingPongIrps(fdoExtension);
newNumBufs /= 2;
} while (!NT_SUCCESS(status) && (newNumBufs >= MIN_PINGPONG_IRPS));
if (!NT_SUCCESS(status)) {
/*
* The device will no longer function !!!
*/
TRAP;
fdoExtension->numPingPongs = 0;
}
}
}
DBGSUCCESS(status, TRUE)
return status;
}
/*
********************************************************************************
* HidpSubmitInterruptRead
********************************************************************************
*
*
*/
NTSTATUS HidpSubmitInterruptRead(
IN FDO_EXTENSION *fdoExt,
HIDCLASS_PINGPONG *pingPong,
BOOLEAN *irpSent)
{
NTSTATUS status = STATUS_SUCCESS;
PIO_STACK_LOCATION irpSp;
KIRQL oldIrql;
BOOLEAN proceed;
LONG oldInterlock;
PIRP irp = pingPong->irp;
ASSERT(irp);
*irpSent = FALSE;
while (1) {
if (NT_SUCCESS(status)) {
HidpSetDeviceBusy(fdoExt);
oldInterlock = InterlockedExchange(&pingPong->ReadInterlock,
PINGPONG_START_READ);
ASSERT(oldInterlock == PINGPONG_END_READ);
irp->Cancel = FALSE;
irp->IoStatus.Status = STATUS_NOT_SUPPORTED;
irpSp = IoGetNextIrpStackLocation(irp);
irpSp->MajorFunction = IRP_MJ_INTERNAL_DEVICE_CONTROL;
irpSp->Parameters.DeviceIoControl.IoControlCode = IOCTL_HID_READ_REPORT;
irpSp->Parameters.DeviceIoControl.OutputBufferLength = fdoExt->maxReportSize;
/*
* Indicate interrupt collection (default).
* We use .InputBufferLength for this
*/
irpSp->Parameters.DeviceIoControl.InputBufferLength = 0;
ASSERT(irp->UserBuffer == pingPong->reportBuffer);
#ifdef _X86_
// this sets off alignment problems on Alpha
ASSERT(*(PULONG)(&pingPong->reportBuffer[fdoExt->maxReportSize]) == HIDCLASS_REPORT_BUFFER_GUARD);
#endif
/*
* Set the completion, passing the FDO extension as context.
*/
IoSetCompletionRoutine( irp,
HidpInterruptReadComplete,
(PVOID)fdoExt,
TRUE,
TRUE,
TRUE );
/*
* Send down the read IRP.
*/
KeResetEvent(&pingPong->sentEvent);
if (pingPong->weAreCancelling) {
//
// Ordering of the next two instructions is crucial, since
// CancelPingPongs will exit after pumpDoneEvent is set, and the
// pingPongs could be deleted after that.
//
DBGVERBOSE(("Pingpong %x cancelled in submit before sending\n", pingPong))
KeSetEvent (&pingPong->sentEvent, 0, FALSE);
KeSetEvent(&pingPong->pumpDoneEvent, 0, FALSE);
status = STATUS_CANCELLED;
break;
} else {
InterlockedIncrement(&fdoExt->outstandingRequests);
DBGVERBOSE(("Sending pingpong %x from Submit\n", pingPong))
status = HidpCallDriver(fdoExt->fdo, irp);
KeSetEvent (&pingPong->sentEvent, 0, FALSE);
*irpSent = TRUE;
}
if (PINGPONG_IMMEDIATE_READ != InterlockedExchange(&pingPong->ReadInterlock,
PINGPONG_END_READ)) {
//
// The read is asynch, will call SubmitInterruptRead from the
// completion routine
//
DBGVERBOSE(("read is pending\n"))
break;
} else {
//
// The read was synchronous (probably bytes in the buffer). The
// completion routine will not call SubmitInterruptRead, so we
// just loop here. This is to prevent us from running out of stack
// space if always call StartRead from the completion routine
//
status = irp->IoStatus.Status;
DBGVERBOSE(("read is looping with status %x\n", status))
}
} else {
if (pingPong->weAreCancelling ){
// We are stopping the read pump.
// set this event and stop resending the pingpong IRP.
DBGVERBOSE(("We are cancelling bit set for pingpong %x\n", pingPong))
KeSetEvent(&pingPong->pumpDoneEvent, 0, FALSE);
} else {
/*
* The device returned error.
* In order to support slightly-broken devices which
* "hiccup" occasionally, we implement a back-off timer
* algorithm; this way, the device gets a second chance,
* but if it spits back error each time, this doesn't
* eat up all the available CPU.
*/
DBGVERBOSE(("Queuing backoff timer on pingpong %x\n", pingPong))
ASSERT((LONG)pingPong->backoffTimerPeriod.HighPart == -1);
ASSERT((LONG)pingPong->backoffTimerPeriod.LowPart < 0);
KeSetTimer( &pingPong->backoffTimer,
pingPong->backoffTimerPeriod,
&pingPong->backoffTimerDPC);
}
break;
}
}
DBGSUCCESS(status, FALSE)
return status;
}
/*
********************************************************************************
* HidpProcessInterruptReport
********************************************************************************
*
* Take the new interrupt read report and either:
* 1. If there is a pending read IRP, use it to satisfy that read IRP
* and complete the read IRP
*
* or
*
* 2. If there is no pending read IRP,
* queue the report for a future read.
*
*/
NTSTATUS HidpProcessInterruptReport(
PHIDCLASS_COLLECTION collection,
PHIDCLASS_FILE_EXTENSION FileExtension,
PUCHAR Report,
ULONG ReportLength,
PIRP *irpToComplete
)
{
KIRQL oldIrql;
NTSTATUS result;
PIRP readIrpToSatisfy;
LockFileExtension(FileExtension, &oldIrql);
/*
* Dequeue the next interrupt read.
*/
readIrpToSatisfy = DequeueInterruptReadIrp(collection, FileExtension);
if (readIrpToSatisfy){
/*
* We have dequeued a pended read IRP
* which we will complete with this report.
*/
ULONG userReportLength;
PCHAR pDest;
PIO_STACK_LOCATION irpSp;
NTSTATUS status;
ASSERT(IsListEmpty(&FileExtension->ReportList));
irpSp = IoGetCurrentIrpStackLocation(readIrpToSatisfy);
pDest = HidpGetSystemAddressForMdlSafe(readIrpToSatisfy->MdlAddress);
if(pDest) {
userReportLength = irpSp->Parameters.Read.Length;
status = HidpCopyInputReportToUser( FileExtension,
Report,
&userReportLength,
pDest);
DBGASSERT(NT_SUCCESS(status),
("HidpCopyInputReportToUser returned status = %x", status),
TRUE)
readIrpToSatisfy->IoStatus.Status = status;
readIrpToSatisfy->IoStatus.Information = userReportLength;
DBG_RECORD_READ(readIrpToSatisfy, userReportLength, (ULONG)Report[0], TRUE)
result = status;
} else {
result = STATUS_INVALID_USER_BUFFER;
readIrpToSatisfy->IoStatus.Status = result;
}
} else {
/*
* We don't have any pending read IRPs.
* So queue this report for the next read.
*/
PHIDCLASS_REPORT report;
ULONG reportSize;
reportSize = FIELD_OFFSET(HIDCLASS_REPORT, UnparsedReport) + ReportLength;
report = ALLOCATEPOOL(NonPagedPool, reportSize);
if (report){
report->reportLength = ReportLength;
RtlCopyMemory(report->UnparsedReport, Report, ReportLength);
EnqueueInterruptReport(FileExtension, report);
result = STATUS_PENDING;
} else {
result = STATUS_INSUFFICIENT_RESOURCES;
}
}
UnlockFileExtension(FileExtension, oldIrql);
/*
* This function is called with the fileExtensionsList spinlock held.
* So we can't complete the IRP here. Pass it back to the caller and it'll
* be completed as soon as we drop all the spinlocks.
*/
*irpToComplete = readIrpToSatisfy;
DBGSUCCESS(result, FALSE)
return result;
}
/*
********************************************************************************
* HidpDistributeInterruptReport
********************************************************************************
*
*
*/
VOID HidpDistributeInterruptReport(
IN PHIDCLASS_COLLECTION hidclassCollection,
PUCHAR Report,
ULONG ReportLength
)
{
PLIST_ENTRY listEntry;
KIRQL oldIrql;
LIST_ENTRY irpsToComplete;
ULONG secureReadMode;
#if DBG
ULONG numRecipients = 0;
ULONG numPending = 0;
ULONG numFailed = 0;
#endif
InitializeListHead(&irpsToComplete);
KeAcquireSpinLock(&hidclassCollection->FileExtensionListSpinLock, &oldIrql);
listEntry = &hidclassCollection->FileExtensionList;
secureReadMode = hidclassCollection->secureReadMode;
while ((listEntry = listEntry->Flink) != &hidclassCollection->FileExtensionList){
PIRP irpToComplete;
PHIDCLASS_FILE_EXTENSION fileExtension = CONTAINING_RECORD(listEntry, HIDCLASS_FILE_EXTENSION, FileList);
NTSTATUS status;
//
// This is to enforce security for devices such as a digitizer on a
// tablet PC at the logon screen
//
if (secureReadMode && !fileExtension->isSecureOpen) {
continue;
}
#if DBG
status =
#endif
HidpProcessInterruptReport(hidclassCollection, fileExtension, Report, ReportLength, &irpToComplete);
if (irpToComplete){
InsertTailList(&irpsToComplete, &irpToComplete->Tail.Overlay.ListEntry);
}
#if DBG
if (status == STATUS_SUCCESS){
}
else if (status == STATUS_PENDING){
numPending++;
}
else {
DBGSUCCESS(status, FALSE)
numFailed++;
}
numRecipients++;
#endif
}
DBG_LOG_REPORT(hidclassCollection->CollectionNumber, numRecipients, numPending, numFailed, Report, ReportLength)
KeReleaseSpinLock(&hidclassCollection->FileExtensionListSpinLock, oldIrql);
/*
* Now that we've dropped all the spinlocks, complete all the dequeued read IRPs.
*/
while (!IsListEmpty(&irpsToComplete)){
PIRP irp;
PLIST_ENTRY listEntry = RemoveHeadList(&irpsToComplete);
irp = CONTAINING_RECORD(listEntry, IRP, Tail.Overlay.ListEntry);
IoCompleteRequest(irp, IO_KEYBOARD_INCREMENT);
}
}
/*
********************************************************************************
* GetPingPongFromIrp
********************************************************************************
*
*
*/
HIDCLASS_PINGPONG *GetPingPongFromIrp(FDO_EXTENSION *fdoExt, PIRP irp)
{
HIDCLASS_PINGPONG *pingPong = NULL;
ULONG i;
for (i = 0; i < fdoExt->numPingPongs; i++){
if (fdoExt->pingPongs[i].irp == irp){
pingPong = &fdoExt->pingPongs[i];
break;
}
}
ASSERT(pingPong);
return pingPong;
}
/*
********************************************************************************
* HidpInterruptReadComplete
********************************************************************************
*
*
*/
NTSTATUS HidpInterruptReadComplete(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp,
IN PVOID Context
)
{
FDO_EXTENSION *fdoExt = (FDO_EXTENSION *)Context;
HIDCLASS_PINGPONG *pingPong;
KIRQL irql;
BOOLEAN startRead;
DBG_COMMON_ENTRY()
DBGLOG_INTSTART()
//
// Track the number of outstanding requests to this device.
//
ASSERT(fdoExt->outstandingRequests > 0 );
InterlockedDecrement(&fdoExt->outstandingRequests);
pingPong = GetPingPongFromIrp(fdoExt, Irp);
if (!pingPong) {
//
// Something is terribly wrong, but do nothing. Hopefully
// just exiting will clear up this pimple.
//
DBGERR(("A pingPong structure could not be found!!! Have this looked at!"))
goto InterruptReadCompleteExit;
}
//
// If ReadInterlock is == START_READ, this func has been completed
// synchronously. Place IMMEDIATE_READ into the interlock to signify this
// situation; this will notify StartRead to loop when IoCallDriver returns.
// Otherwise, we have been completed async and it is safe to call StartRead()
//
startRead =
(PINGPONG_START_READ !=
InterlockedCompareExchange(&pingPong->ReadInterlock,
PINGPONG_IMMEDIATE_READ,
PINGPONG_START_READ));
/*
* Take appropriate action based on the completion code of this pingpong irp.
*/
if (NT_SUCCESS(Irp->IoStatus.Status)){
/*
* We've read one or more input reports.
* They are sitting consecutively in Irp->UserBuffer.
*/
PUCHAR reportStart = Irp->UserBuffer;
LONG bytesRemaining = (LONG)Irp->IoStatus.Information;
DBGASSERT(bytesRemaining > 0, ("BAD HARDWARE. Device returned zero bytes. If this happens repeatedly, remove device."), FALSE);
/*
* Deliver each report separately.
*/
while (bytesRemaining > 0){
UCHAR reportId;
PHIDP_REPORT_IDS reportIdentifier;
/*
* If the first report ID is 0, then there is only one report id
* and it is known implicitly by the device, so it is not included
* in the reports sent to or from the device.
* Otherwise, there are multiple report ids and the report id is the
* first byte of the report.
*/
if (fdoExt->deviceDesc.ReportIDs[0].ReportID == 0){
/*
* This device has only a single input report ID, so call it report id 0;
*/
reportId = 0;
}
else {
/*
* This device has multiple input report IDs, so each report
* begins with a UCHAR report ID.
*/
reportId = *reportStart;
DBGASSERT(reportId,
("Bad Hardware. Not returning a report id although it has multiple ids."),
FALSE) // Bad hardware, bug 354829.
reportStart += sizeof(UCHAR);
bytesRemaining--;
}
/*
* Extract the report identifier with the given id from the HID device extension.
*/
reportIdentifier = GetReportIdentifier(fdoExt, reportId);
if (reportIdentifier){
LONG reportDataLen = (reportId ?
reportIdentifier->InputLength-1 :
reportIdentifier->InputLength);
if ((reportDataLen > 0) && (reportDataLen <= bytesRemaining)){
PHIDCLASS_COLLECTION collection;
PHIDP_COLLECTION_DESC hidCollectionDesc;
/*
* This report represents the state of some collection on the device.
* Find that collection.
*/
collection = GetHidclassCollection( fdoExt,
reportIdentifier->CollectionNumber);
hidCollectionDesc = GetCollectionDesc( fdoExt,
reportIdentifier->CollectionNumber);
if (collection && hidCollectionDesc){
PDO_EXTENSION *pdoExt;
/*
* The collection's inputLength is the size of the
* largest report (including report id); so it should
* be at least as big as this one.
*/
ASSERT(hidCollectionDesc->InputLength >= reportDataLen+1);
/*
* Make sure that the PDO for this collection has gotten
* START_DEVICE before returning anything for it.
* (collection-PDOs can get REMOVE_DEVICE/START_DEVICE intermittently).
*/
if (ISPTR(fdoExt->collectionPdoExtensions)
&& ISPTR(fdoExt->collectionPdoExtensions[collection->CollectionIndex])) {
pdoExt = &fdoExt->collectionPdoExtensions[collection->CollectionIndex]->pdoExt;
ASSERT(ISPTR(pdoExt));
if (pdoExt->state == COLLECTION_STATE_RUNNING){
/*
* "Cook" the report
* (if it doesn't already have a report id byte, add one).
*/
ASSERT(ISPTR(collection->cookedInterruptReportBuf));
collection->cookedInterruptReportBuf[0] = reportId;
RtlCopyMemory( collection->cookedInterruptReportBuf+1,
reportStart,
reportDataLen);
/*
* If this report contains a power-button event, alert this system.
*/
CheckReportPowerEvent( fdoExt,
collection,
collection->cookedInterruptReportBuf,
hidCollectionDesc->InputLength);
/*
* Distribute the report to all of the open file objects on this collection.
*/
HidpDistributeInterruptReport(collection,
collection->cookedInterruptReportBuf,
hidCollectionDesc->InputLength);
}
else {
DBGVERBOSE(("Report dropped because collection-PDO not started (pdoExt->state = %d).", pdoExt->state))
}
}
else {
DBGVERBOSE(("Report dropped because collection-PDO doesn't exist"))
}
}
else {
// PDO hasn't been initialized yet. Throw away data.
DBGVERBOSE(("Report dropped because collection-PDO not initialized."))
// TRAP;
break;
}
}
else {
DBGASSERT(reportDataLen > 0, ("Device returning report id with zero-length input report as part of input data."), FALSE)
if (reportDataLen > bytesRemaining) {
DBGVERBOSE(("Device has corrupt input report"));
}
break;
}
/*
* Move to the next report in the buffer.
*/
bytesRemaining -= reportDataLen;
reportStart += reportDataLen;
}
else {
//
// We have thrown away data because we couldn't find a report
// identifier corresponding to this data that we've been
// returned. Bad hardware, bug 354829.
//
break;
}
}
/*
* The read succeeded.
* Reset the backoff timer stuff (for when reads fail)
* and re-submit this ping-pong IRP.
*/
pingPong->backoffTimerPeriod.HighPart = -1;
pingPong->backoffTimerPeriod.LowPart = -10000000;
}
//
// Business as usual.
//
if (startRead) {
if (pingPong->weAreCancelling ){
// We are stopping the read pump.
// Set this event and stop resending the pingpong IRP.
DBGVERBOSE(("We are cancelling bit set for pingpong %x\n", pingPong))
KeSetEvent(&pingPong->pumpDoneEvent, 0, FALSE);
} else {
if (NT_SUCCESS(Irp->IoStatus.Status)){
BOOLEAN irpSent;
DBGVERBOSE(("Submitting pingpong %x from completion routine\n", pingPong))
HidpSubmitInterruptRead(fdoExt, pingPong, &irpSent);
} else {
/*
* The device returned error.
* In order to support slightly-broken devices which
* "hiccup" occasionally, we implement a back-off timer
* algorithm; this way, the device gets a second chance,
* but if it spits back error each time, this doesn't
* eat up all the available CPU.
*/
#if DBG
if (dbgTrapOnHiccup){
DBGERR(("Device 'hiccuped' (status=%xh); setting backoff timer (fdoExt=%ph)...", Irp->IoStatus.Status, fdoExt))
}
#endif
DBGVERBOSE(("Device returned error %x on pingpong %x\n", Irp->IoStatus.Status, pingPong))
ASSERT((LONG)pingPong->backoffTimerPeriod.HighPart == -1);
ASSERT((LONG)pingPong->backoffTimerPeriod.LowPart < 0);
KeSetTimer( &pingPong->backoffTimer,
pingPong->backoffTimerPeriod,
&pingPong->backoffTimerDPC);
}
}
}
InterruptReadCompleteExit:
DBGLOG_INTEND()
DBG_COMMON_EXIT()
/*
* ALWAYS return STATUS_MORE_PROCESSING_REQUIRED;
* otherwise, the irp is required to have a thread.
*/
return STATUS_MORE_PROCESSING_REQUIRED;
}
/*
********************************************************************************
* HidpStartAllPingPongs
********************************************************************************
*
*
*/
NTSTATUS HidpStartAllPingPongs(FDO_EXTENSION *fdoExt)
{
NTSTATUS status = STATUS_SUCCESS;
ULONG i;
ASSERT(fdoExt->numPingPongs > 0);
for (i = 0; i < fdoExt->numPingPongs; i++){
BOOLEAN irpSent;
// Different threads may be trying to start this pump at the
// same time due to idle notification. Must only start once.
if (fdoExt->pingPongs[i].pumpDoneEvent.Header.SignalState) {
fdoExt->pingPongs[i].ReadInterlock = PINGPONG_END_READ;
KeResetEvent(&fdoExt->pingPongs[i].pumpDoneEvent);
DBGVERBOSE(("Starting pingpong %x from HidpStartAllPingPongs\n", &fdoExt->pingPongs[i]))
status = HidpSubmitInterruptRead(fdoExt, &fdoExt->pingPongs[i], &irpSent);
if (!NT_SUCCESS(status)){
if (irpSent){
DBGWARN(("Initial read failed with status %xh.", status))
#if DBG
if (dbgTrapOnHiccup){
DBGERR(("Device 'hiccuped' ?? (fdoExt=%ph).", fdoExt))
}
#endif
/*
* We'll let the back-off logic in the completion
* routine deal with this.
*/
status = STATUS_SUCCESS;
}
else {
DBGERR(("Initial read failed, irp not sent, status = %xh.", status))
break;
}
}
}
}
if (status == STATUS_PENDING){
status = STATUS_SUCCESS;
}
DBGSUCCESS(status, TRUE)
return status;
}
/*
********************************************************************************
* CancelAllPingPongIrps
********************************************************************************
*
*
*/
VOID CancelAllPingPongIrps(FDO_EXTENSION *fdoExt)
{
ULONG i;
for (i = 0; i < fdoExt->numPingPongs; i++){
HIDCLASS_PINGPONG *pingPong = &fdoExt->pingPongs[i];
DBGVERBOSE(("Cancelling pingpong %x\n", pingPong))
ASSERT(pingPong->sig == PINGPONG_SIG);
ASSERT(!pingPong->weAreCancelling);
//
// The order of the following instructions is crucial. We must set
// the weAreCancelling bit before waiting on the sentEvent, and the
// last thing that we should wait on is the pumpDoneEvent, which
// indicates that the read loop has finished all reads and will never
// run again.
//
// Note that we don't need spinlocks to guard since we only have two
// threads touching pingpong structures; the read pump thread and the
// pnp thread. PNP irps are synchronous, so those are safe. Using the
// weAreCancelling bit and the two events, sentEvent and pumpDoneEvent,
// the pnp irps are synchronized with the pnp routines. This insures
// that this cancel routine doesn't exit until the read pump has
// signalled the pumpDoneEvent and exited, hence the pingpong
// structures aren't ripped out from underneath it.
//
// If we have a backoff timer queued, it will eventually fire and
// call the submitinterruptread routine to restart reads. This will
// exit eventually, because we have set the weAreCancelling bit.
//
InterlockedIncrement(&pingPong->weAreCancelling);
{
/*
* Synchronize with the irp's completion routine.
*/
#if DBG
UCHAR beforeIrql = KeGetCurrentIrql();
UCHAR afterIrql;
PVOID cancelRoutine = (PVOID)pingPong->irp->CancelRoutine;
#endif
KeWaitForSingleObject(&pingPong->sentEvent,
Executive, // wait reason
KernelMode,
FALSE, // not alertable
NULL ); // no timeout
DBGVERBOSE(("Pingpong sent event set for pingpong %x\n", pingPong))
IoCancelIrp(pingPong->irp);
#if DBG
afterIrql = KeGetCurrentIrql();
if (afterIrql != beforeIrql){
DBGERR(("CancelAllPingPongIrps: cancel routine at %ph changed irql from %d to %d.", cancelRoutine, beforeIrql, afterIrql))
}
#endif
}
/*
* Cancelling the IRP causes a lower driver to
* complete it (either in a cancel routine or when
* the driver checks Irp->Cancel just before queueing it).
* Wait for the IRP to actually get cancelled.
*/
KeWaitForSingleObject( &pingPong->pumpDoneEvent,
Executive, // wait reason
KernelMode,
FALSE, // not alertable
NULL ); // no timeout
InterlockedDecrement(&pingPong->weAreCancelling);
DBGVERBOSE(("Pingpong pump done event set for %x\n", pingPong))
}
}
/*
********************************************************************************
* DestroyPingPongs
********************************************************************************
*
*
*/
VOID DestroyPingPongs(FDO_EXTENSION *fdoExt)
{
if (ISPTR(fdoExt->pingPongs)){
ULONG i;
CancelAllPingPongIrps(fdoExt);
for (i = 0; i < fdoExt->numPingPongs; i++){
IoFreeIrp(fdoExt->pingPongs[i].irp);
ExFreePool(fdoExt->pingPongs[i].reportBuffer);
#if DBG
fdoExt->pingPongs[i].sig = 0xDEADBEEF;
#endif
}
ExFreePool(fdoExt->pingPongs);
fdoExt->pingPongs = BAD_POINTER;
}
}
/*
********************************************************************************
* HidpPingpongBackoffTimerDpc
********************************************************************************
*
*
*
*/
VOID HidpPingpongBackoffTimerDpc(
IN PKDPC Dpc,
IN PVOID DeferredContext,
IN PVOID SystemArgument1,
IN PVOID SystemArgument2
)
{
HIDCLASS_PINGPONG *pingPong = (HIDCLASS_PINGPONG *)DeferredContext;
BOOLEAN irpSent;
ASSERT(pingPong->sig == PINGPONG_SIG);
/*
* Increase the back-off time by 1 second, up to a max of 5 secs
* (in negative 100-nanosecond units).
*/
ASSERT((LONG)pingPong->backoffTimerPeriod.HighPart == -1);
ASSERT((LONG)pingPong->backoffTimerPeriod.LowPart < 0);
if ((LONG)pingPong->backoffTimerPeriod.LowPart > -50000000){
(LONG)pingPong->backoffTimerPeriod.LowPart -= 10000000;
}
DBGVERBOSE(("Submitting Pingpong %x from backoff\n", pingPong))
//
// If we are being removed, or the CancelAllPingPongIrps has been called,
// this call will take care of things.
//
HidpSubmitInterruptRead(pingPong->myFdoExt, pingPong, &irpSent);
}