Sample Code
Windows Driver Samples/ ClassPnP Storage Class Driver Library/ C++/ src/ retry.c/
/*++
Copyright (C) Microsoft Corporation, 1991 - 2010
Module Name:
retry.c
Abstract:
Packet retry routines for CLASSPNP
Environment:
kernel mode only
Notes:
Revision History:
--*/
#include "classp.h"
#include "debug.h"
#ifdef DEBUG_USE_WPP
#include "retry.tmh"
#endif
/*
* InterpretTransferPacketError
*
* Interpret the SRB error into a meaningful IRP status.
* ClassInterpretSenseInfo also may modify the SRB for the retry.
*
* Return TRUE iff packet should be retried.
*/
BOOLEAN InterpretTransferPacketError(PTRANSFER_PACKET Pkt)
{
PFUNCTIONAL_DEVICE_EXTENSION fdoExtension = Pkt->Fdo->DeviceExtension;
PCLASS_PRIVATE_FDO_DATA fdoData = fdoExtension->PrivateFdoData;
ULONG timesAlreadyRetried;
BOOLEAN shouldRetry = FALSE;
PCDB pCdb = ClasspTransferPacketGetCdb(Pkt);
/*
* Interpret the error using the returned sense info first.
*/
Pkt->RetryIn100nsUnits = 0;
/*
* Pre-calculate the number of times the IO has already been
* retried, so that all InterpretSenseInfo routines get the right value.
*/
if (pCdb->MEDIA_REMOVAL.OperationCode == SCSIOP_MEDIUM_REMOVAL)
{
timesAlreadyRetried = NUM_LOCKMEDIAREMOVAL_RETRIES - Pkt->NumRetries;
}
else if ((pCdb->MODE_SENSE.OperationCode == SCSIOP_MODE_SENSE) ||
(pCdb->MODE_SENSE.OperationCode == SCSIOP_MODE_SENSE10))
{
timesAlreadyRetried = NUM_MODESENSE_RETRIES - Pkt->NumRetries;
}
else if ((pCdb->CDB10.OperationCode == SCSIOP_READ_CAPACITY) ||
(pCdb->CDB16.OperationCode == SCSIOP_READ_CAPACITY16))
{
timesAlreadyRetried = NUM_DRIVECAPACITY_RETRIES - Pkt->NumRetries;
}
else if (IS_SCSIOP_READWRITE(pCdb->CDB10.OperationCode))
{
timesAlreadyRetried = fdoData->MaxNumberOfIoRetries - Pkt->NumRetries;
}
else if (pCdb->TOKEN_OPERATION.OperationCode == SCSIOP_POPULATE_TOKEN &&
pCdb->TOKEN_OPERATION.ServiceAction == SERVICE_ACTION_POPULATE_TOKEN)
{
timesAlreadyRetried = NUM_POPULATE_TOKEN_RETRIES - Pkt->NumRetries;
}
else if (pCdb->TOKEN_OPERATION.OperationCode == SCSIOP_WRITE_USING_TOKEN &&
pCdb->TOKEN_OPERATION.ServiceAction == SERVICE_ACTION_WRITE_USING_TOKEN)
{
timesAlreadyRetried = NUM_WRITE_USING_TOKEN_RETRIES - Pkt->NumRetries;
}
else if (ClasspIsReceiveTokenInformation(pCdb))
{
timesAlreadyRetried = NUM_RECEIVE_TOKEN_INFORMATION_RETRIES - Pkt->NumRetries;
}
else
{
TracePrint((TRACE_LEVEL_ERROR, TRACE_FLAG_GENERAL, "Unhandled SRB Function %xh in error path for packet %p (did miniport change Srb.Cdb.OperationCode ?)", (ULONG)pCdb->CDB10.OperationCode, Pkt));
timesAlreadyRetried = 0;
}
if (fdoData->InterpretSenseInfo != NULL) {
SCSI_REQUEST_BLOCK tempSrb = {0};
PSCSI_REQUEST_BLOCK srbPtr = (PSCSI_REQUEST_BLOCK)Pkt->Srb;
// SAL annotation and ClassInitializeEx() both validate this
NT_ASSERT(fdoData->InterpretSenseInfo->Interpret != NULL);
//
// If class driver does not support extended SRB and this is
// an extended SRB, convert to legacy SRB and pass to class
// driver.
//
if ((Pkt->Srb->Function == SRB_FUNCTION_STORAGE_REQUEST_BLOCK) &&
((fdoExtension->CommonExtension.DriverExtension->SrbSupport &
CLASS_SRB_STORAGE_REQUEST_BLOCK) == 0)) {
ClasspConvertToScsiRequestBlock(&tempSrb, (PSTORAGE_REQUEST_BLOCK)Pkt->Srb);
srbPtr = &tempSrb;
}
shouldRetry = fdoData->InterpretSenseInfo->Interpret(Pkt->Fdo,
Pkt->OriginalIrp,
srbPtr,
IRP_MJ_SCSI,
0,
timesAlreadyRetried,
Pkt->RetryHistory,
&Pkt->Irp->IoStatus.Status,
&Pkt->RetryIn100nsUnits);
}
else if (pCdb->MEDIA_REMOVAL.OperationCode == SCSIOP_MEDIUM_REMOVAL){
ULONG retryIntervalSeconds = 0;
/*
* This is an Ejection Control SRB. Interpret its sense info specially.
*/
shouldRetry = ClassInterpretSenseInfo(
Pkt->Fdo,
(PSCSI_REQUEST_BLOCK)Pkt->Srb,
IRP_MJ_SCSI,
0,
timesAlreadyRetried,
&Pkt->Irp->IoStatus.Status,
&retryIntervalSeconds);
if (shouldRetry){
/*
* If the device is not ready, wait at least 2 seconds before retrying.
*/
PVOID senseInfoBuffer = ClasspTransferPacketGetSenseInfoBuffer(Pkt);
UCHAR senseInfoBufferLength = ClasspTransferPacketGetSenseInfoBufferLength(Pkt);
BOOLEAN validSense = FALSE;
UCHAR additionalSenseCode = 0;
BOOLEAN setRetryIntervalSeconds = FALSE;
validSense = ScsiGetSenseKeyAndCodes(senseInfoBuffer,
senseInfoBufferLength,
SCSI_SENSE_OPTIONS_FIXED_FORMAT_IF_UNKNOWN_FORMAT_INDICATED,
NULL,
&additionalSenseCode,
NULL);
if (validSense) {
if ((Pkt->Irp->IoStatus.Status == STATUS_DEVICE_NOT_READY) &&
(additionalSenseCode == SCSI_ADSENSE_LUN_NOT_READY)) {
setRetryIntervalSeconds = TRUE;
}
}
if (!setRetryIntervalSeconds && (SRB_STATUS(Pkt->Srb->SrbStatus) == SRB_STATUS_SELECTION_TIMEOUT)) {
setRetryIntervalSeconds = TRUE;
}
if (setRetryIntervalSeconds) {
retryIntervalSeconds = MAX(retryIntervalSeconds, 2);
}
}
if (shouldRetry)
{
Pkt->RetryIn100nsUnits = retryIntervalSeconds;
Pkt->RetryIn100nsUnits *= 1000 * 1000 * 10;
}
}
else if ((pCdb->MODE_SENSE.OperationCode == SCSIOP_MODE_SENSE) ||
(pCdb->MODE_SENSE.OperationCode == SCSIOP_MODE_SENSE10)){
ULONG retryIntervalSeconds = 0;
/*
* This is an Mode Sense SRB. Interpret its sense info specially.
*/
shouldRetry = ClassInterpretSenseInfo(
Pkt->Fdo,
(PSCSI_REQUEST_BLOCK)Pkt->Srb,
IRP_MJ_SCSI,
0,
timesAlreadyRetried,
&Pkt->Irp->IoStatus.Status,
&retryIntervalSeconds);
if (shouldRetry){
/*
* If the device is not ready, wait at least 2 seconds before retrying.
*/
PVOID senseInfoBuffer = ClasspTransferPacketGetSenseInfoBuffer(Pkt);
UCHAR senseInfoBufferLength = ClasspTransferPacketGetSenseInfoBufferLength(Pkt);
BOOLEAN validSense = FALSE;
UCHAR additionalSenseCode = 0;
BOOLEAN setRetryIntervalSeconds = FALSE;
NT_ASSERT(senseInfoBuffer);
validSense = ScsiGetSenseKeyAndCodes(senseInfoBuffer,
senseInfoBufferLength,
SCSI_SENSE_OPTIONS_FIXED_FORMAT_IF_UNKNOWN_FORMAT_INDICATED,
NULL,
&additionalSenseCode,
NULL);
if (validSense) {
if ((Pkt->Irp->IoStatus.Status == STATUS_DEVICE_NOT_READY) &&
(additionalSenseCode == SCSI_ADSENSE_LUN_NOT_READY)) {
setRetryIntervalSeconds = TRUE;
}
}
if (!setRetryIntervalSeconds && (SRB_STATUS(Pkt->Srb->SrbStatus) == SRB_STATUS_SELECTION_TIMEOUT)) {
setRetryIntervalSeconds = TRUE;
}
if (setRetryIntervalSeconds) {
retryIntervalSeconds = MAX(retryIntervalSeconds, 2);
}
}
/*
* Some special cases for mode sense.
*/
if (Pkt->Irp->IoStatus.Status == STATUS_VERIFY_REQUIRED){
shouldRetry = TRUE;
}
else if (SRB_STATUS(Pkt->Srb->SrbStatus) == SRB_STATUS_DATA_OVERRUN){
/*
* This is a HACK.
* Atapi returns SRB_STATUS_DATA_OVERRUN when it really means
* underrun (i.e. success, and the buffer is longer than needed).
* So treat this as a success.
* When the caller of this function sees that the status was changed to success,
* it will add the transferred length to the original irp.
*/
Pkt->Irp->IoStatus.Status = STATUS_SUCCESS;
shouldRetry = FALSE;
}
if (shouldRetry)
{
Pkt->RetryIn100nsUnits = retryIntervalSeconds;
Pkt->RetryIn100nsUnits *= 1000 * 1000 * 10;
}
}
else if ((pCdb->CDB10.OperationCode == SCSIOP_READ_CAPACITY) ||
(pCdb->CDB16.OperationCode == SCSIOP_READ_CAPACITY16)) {
ULONG retryIntervalSeconds = 0;
/*
* This is a Drive Capacity SRB. Interpret its sense info specially.
*/
shouldRetry = ClassInterpretSenseInfo(
Pkt->Fdo,
(PSCSI_REQUEST_BLOCK)Pkt->Srb,
IRP_MJ_SCSI,
0,
timesAlreadyRetried,
&Pkt->Irp->IoStatus.Status,
&retryIntervalSeconds);
if (Pkt->Irp->IoStatus.Status == STATUS_VERIFY_REQUIRED){
shouldRetry = TRUE;
}
if (shouldRetry)
{
Pkt->RetryIn100nsUnits = retryIntervalSeconds;
Pkt->RetryIn100nsUnits *= 1000 * 1000 * 10;
}
}
else if (IS_SCSIOP_READWRITE(pCdb->CDB10.OperationCode)) {
ULONG retryIntervalSeconds = 0;
/*
* This is a Read/Write Data packet.
*/
PIO_STACK_LOCATION origCurrentSp = IoGetCurrentIrpStackLocation(Pkt->OriginalIrp);
shouldRetry = ClassInterpretSenseInfo(Pkt->Fdo,
(PSCSI_REQUEST_BLOCK)Pkt->Srb,
origCurrentSp->MajorFunction,
0,
timesAlreadyRetried,
&Pkt->Irp->IoStatus.Status,
&retryIntervalSeconds);
/*
* Deal with some special cases.
*/
if (Pkt->Irp->IoStatus.Status == STATUS_INSUFFICIENT_RESOURCES){
/*
* We are in extreme low-memory stress.
* We will retry in smaller chunks.
*/
shouldRetry = TRUE;
}
else if (TEST_FLAG(origCurrentSp->Flags, SL_OVERRIDE_VERIFY_VOLUME) &&
(Pkt->Irp->IoStatus.Status == STATUS_VERIFY_REQUIRED)){
/*
* We are still verifying a (possibly) reloaded disk/cdrom.
* So retry the request.
*/
Pkt->Irp->IoStatus.Status = STATUS_IO_DEVICE_ERROR;
shouldRetry = TRUE;
}
if (shouldRetry)
{
Pkt->RetryIn100nsUnits = retryIntervalSeconds;
Pkt->RetryIn100nsUnits *= 1000 * 1000 * 10;
}
} else if (ClasspIsOffloadDataTransferCommand(pCdb)) {
ULONG retryIntervalSeconds = 0;
Pkt->TransferCount = 0;
shouldRetry = ClassInterpretSenseInfo(
Pkt->Fdo,
(PSCSI_REQUEST_BLOCK)Pkt->Srb,
IRP_MJ_SCSI,
0,
timesAlreadyRetried,
&Pkt->Irp->IoStatus.Status,
&retryIntervalSeconds);
if (shouldRetry) {
Pkt->RetryIn100nsUnits = retryIntervalSeconds;
Pkt->RetryIn100nsUnits *= 1000 * 1000 * 10;
} else {
if (ClasspIsTokenOperation(pCdb)) {
PVOID senseInfoBuffer = ClasspTransferPacketGetSenseInfoBuffer(Pkt);
UCHAR senseInfoBufferLength = ClasspTransferPacketGetSenseInfoBufferLength(Pkt);
BOOLEAN validSense = FALSE;
UCHAR senseKey = 0;
UCHAR additionalSenseCode = 0;
UCHAR additionalSenseQual = 0;
BOOLEAN isInformationValid = FALSE;
ULONGLONG information = 0;
NT_ASSERT(senseInfoBuffer);
validSense = ScsiGetSenseKeyAndCodes(senseInfoBuffer,
senseInfoBufferLength,
SCSI_SENSE_OPTIONS_FIXED_FORMAT_IF_UNKNOWN_FORMAT_INDICATED,
&senseKey,
&additionalSenseCode,
&additionalSenseQual);
if (validSense) {
//
// If this is a data underrun condition (i.e. target truncated the offload data transfer),
// the SenseData's Information field may have the TransferCount.
//
if ((senseKey == SCSI_SENSE_COPY_ABORTED || senseKey == SCSI_SENSE_ABORTED_COMMAND) &&
(additionalSenseCode == SCSI_ADSENSE_COPY_TARGET_DEVICE_ERROR && additionalSenseQual == SCSI_SENSEQ_DATA_UNDERRUN)) {
//
// Sense data in Descriptor format
//
if (IsDescriptorSenseDataFormat(senseInfoBuffer)) {
PVOID startBuffer = NULL;
UCHAR startBufferLength = 0;
if (ScsiGetSenseDescriptor(senseInfoBuffer,
SrbGetSenseInfoBufferLength(Pkt->Srb),
&startBuffer,
&startBufferLength)) {
UCHAR outType;
PVOID outBuffer = NULL;
UCHAR outBufferLength = 0;
UCHAR typeList[1] = {SCSI_SENSE_DESCRIPTOR_TYPE_INFORMATION};
if (ScsiGetNextSenseDescriptorByType(startBuffer,
startBufferLength,
typeList,
ARRAYSIZE(typeList),
&outType,
&outBuffer,
&outBufferLength)) {
if (outType == SCSI_SENSE_DESCRIPTOR_TYPE_INFORMATION) {
if (ScsiValidateInformationSenseDescriptor(outBuffer, outBufferLength)) {
REVERSE_BYTES_QUAD(&information, &(((PSCSI_SENSE_DESCRIPTOR_INFORMATION)outBuffer)->Information));
isInformationValid = TRUE;
}
} else {
//
// ScsiGetNextDescriptorByType should only return a type that is specified by us.
//
NT_ASSERT(FALSE);
}
}
}
} else {
//
// Sense data in Fixed format
//
REVERSE_BYTES(&information, &(((PFIXED_SENSE_DATA)senseInfoBuffer)->Information));
isInformationValid = TRUE;
}
if (isInformationValid) {
Pkt->TransferCount = information;
}
}
}
}
}
}
else {
TracePrint((TRACE_LEVEL_ERROR, TRACE_FLAG_GENERAL, "Unhandled SRB Function %xh in error path for packet %p (did miniport change Srb.Cdb.OperationCode ?)", (ULONG)pCdb->CDB10.OperationCode, Pkt));
}
return shouldRetry;
}
/*
* RetryTransferPacket
*
* Retry sending a TRANSFER_PACKET.
*
* Return TRUE iff the packet is complete.
* (if so the status in pkt->irp is the final status).
*/
BOOLEAN RetryTransferPacket(PTRANSFER_PACKET Pkt)
{
BOOLEAN packetDone;
TracePrint((TRACE_LEVEL_INFORMATION, TRACE_FLAG_GENERAL, "retrying failed transfer (pkt=%ph, op=%s)", Pkt, DBGGETSCSIOPSTR(Pkt->Srb)));
NT_ASSERT(Pkt->NumRetries > 0 || Pkt->RetryHistory);
Pkt->NumRetries--;
//
// If this is the last retry, then turn off disconnect, sync transfer,
// and tagged queuing. On all other retries, leave the original settings.
//
if ( 0 == Pkt->NumRetries ) {
/*
* Tone down performance on the retry.
* This increases the chance for success on the retry.
* We've seen instances of drives that fail consistently but then start working
* once this scale-down is applied.
*/
SrbSetSrbFlags(Pkt->Srb, SRB_FLAGS_DISABLE_DISCONNECT);
SrbSetSrbFlags(Pkt->Srb, SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
SrbClearSrbFlags(Pkt->Srb, SRB_FLAGS_QUEUE_ACTION_ENABLE);
SrbSetRequestTag(Pkt->Srb, SP_UNTAGGED);
}
if (Pkt->Irp->IoStatus.Status == STATUS_INSUFFICIENT_RESOURCES) {
PCDB pCdb = SrbGetCdb(Pkt->Srb);
UCHAR cdbOpcode = 0;
BOOLEAN isReadWrite = FALSE;
PFUNCTIONAL_DEVICE_EXTENSION fdoExtension = Pkt->Fdo->DeviceExtension;
PCLASS_PRIVATE_FDO_DATA fdoData = fdoExtension->PrivateFdoData;
if (pCdb) {
cdbOpcode = pCdb->CDB10.OperationCode;
isReadWrite = IS_SCSIOP_READWRITE(cdbOpcode);
}
if ((Pkt->DriverUsesStartIO) &&
( (cdbOpcode == SCSIOP_WRITE6 ) ||
(cdbOpcode == SCSIOP_WRITE ) ||
(cdbOpcode == SCSIOP_WRITE12) ||
(cdbOpcode == SCSIOP_WRITE16) )) {
/* don't retry writes in super-low-memory conditions if the
* driver must serialize against StartIO. This is because
* some write methods used in such drivers cannot accept
* random-sized writes. (i.e CD-RW in packet writing mode)
* Reads, however, are always safe to split up.
*/
SET_FLAG(fdoData->TrackingFlags, TRACKING_FORWARD_PROGRESS_PATH1);
packetDone = TRUE;
}
else if (Pkt->InLowMemRetry || !isReadWrite){
/*
* This should never happen under normal circumstances.
* The memory manager guarantees that at least four pages will
* be available to allow forward progress in the port driver.
* So a one-page transfer should never fail with insufficient resources.
*
* However, it is possible to get in here with virtual storage
* or thin provisioned storage for example.
* A single sector write can trigger an allocation request and
* presently a forward progress guarantee is not provided.
* VHD also may have some limitations in forward progress guarantee.
* And USB too might also fall into this category.
*/
SET_FLAG(fdoData->TrackingFlags, TRACKING_FORWARD_PROGRESS_PATH2);
packetDone = TRUE;
}
else {
/*
* We are in low-memory stress.
* Start the low-memory retry state machine, which tries to
* resend the packet in little one-page chunks.
*/
SET_FLAG(fdoData->TrackingFlags, TRACKING_FORWARD_PROGRESS_PATH3);
InitLowMemRetry(Pkt,
Pkt->BufPtrCopy,
Pkt->BufLenCopy,
Pkt->TargetLocationCopy);
StepLowMemRetry(Pkt);
packetDone = FALSE;
}
}
else {
/*
* Retry the packet by simply resending it after a delay.
* Put the packet back in the pending queue and
* schedule a timer to retry the transfer.
*
* Do not call SetupReadWriteTransferPacket again because:
* (1) The minidriver may have set some bits
* in the SRB that it needs again and
* (2) doing so would reset numRetries.
*
* BECAUSE we do not call SetupReadWriteTransferPacket again,
* we have to reset a couple fields in the SRB that
* some miniports overwrite when they fail an SRB.
*/
SrbSetDataBuffer(Pkt->Srb, Pkt->BufPtrCopy);
SrbSetDataTransferLength(Pkt->Srb, Pkt->BufLenCopy);
TransferPacketQueueRetryDpc(Pkt);
packetDone = FALSE;
}
return packetDone;
}
VOID TransferPacketQueueRetryDpc(PTRANSFER_PACKET Pkt)
{
KeInitializeDpc(&Pkt->RetryTimerDPC, TransferPacketRetryTimerDpc, Pkt);
if (Pkt->RetryIn100nsUnits == 0){
KeInsertQueueDpc(&Pkt->RetryTimerDPC, NULL, NULL);
}
else {
LARGE_INTEGER timerPeriod;
NT_ASSERT(Pkt->RetryIn100nsUnits < 100 * 1000 * 1000 * 10); // sanity check -- 100 seconds is normally too long
timerPeriod.QuadPart = -(Pkt->RetryIn100nsUnits);
KeInitializeTimer(&Pkt->RetryTimer);
KeSetTimer(&Pkt->RetryTimer, timerPeriod, &Pkt->RetryTimerDPC);
}
}
VOID TransferPacketRetryTimerDpc( IN PKDPC Dpc,
IN PVOID DeferredContext,
IN PVOID SystemArgument1,
IN PVOID SystemArgument2)
{
PTRANSFER_PACKET pkt;
PDEVICE_OBJECT fdo;
PFUNCTIONAL_DEVICE_EXTENSION fdoExtension;
_Analysis_assume_(DeferredContext != NULL);
pkt = (PTRANSFER_PACKET)DeferredContext;
fdo = pkt->Fdo;
fdoExtension = fdo->DeviceExtension;
UNREFERENCED_PARAMETER(Dpc);
UNREFERENCED_PARAMETER(SystemArgument1);
UNREFERENCED_PARAMETER(SystemArgument2);
/*
* Sometimes the port driver can allocates a new 'sense' buffer
* to report transfer errors, e.g. when the default sense buffer
* is too small. If so, it is up to us to free it.
* Now that we're done using the sense info, free it if appropriate.
* Then clear the sense buffer so it doesn't pollute future errors returned in this packet.
*/
if (PORT_ALLOCATED_SENSE_EX(fdoExtension, pkt->Srb)) {
TracePrint((TRACE_LEVEL_INFORMATION, TRACE_FLAG_RW, "Freeing port-allocated sense buffer for pkt %ph.", pkt));
FREE_PORT_ALLOCATED_SENSE_BUFFER_EX(fdoExtension, pkt->Srb);
SrbSetSenseInfoBuffer(pkt->Srb, &pkt->SrbErrorSenseData);
SrbSetSenseInfoBufferLength(pkt->Srb, sizeof(pkt->SrbErrorSenseData));
}
else {
NT_ASSERT(SrbGetSenseInfoBuffer(pkt->Srb) == &pkt->SrbErrorSenseData);
NT_ASSERT(SrbGetSenseInfoBufferLength(pkt->Srb) <= sizeof(pkt->SrbErrorSenseData));
}
RtlZeroMemory(&pkt->SrbErrorSenseData, sizeof(pkt->SrbErrorSenseData));
SubmitTransferPacket(pkt);
}
VOID InitLowMemRetry(PTRANSFER_PACKET Pkt, PVOID BufPtr, ULONG Len, LARGE_INTEGER TargetLocation)
{
NT_ASSERT(Len > 0);
NT_ASSERT(!Pkt->InLowMemRetry);
if (Pkt->DriverUsesStartIO)
{
/*
* special case: StartIO-based writing must stay serialized for performance
* and proper operations (i.e. sequential writing mode). If need more than
* one transfer to perform this operation, and it's a StartIO-based driver
* (such as CDROM), then just use a single packet and use the retry logic
* that's already built-in to the packet engine. Note that low-mem retry
* cannot be used directly because some write methods do not work if the
* writes are only PAGE_SIZE (i.e. packet writing may corrupt data).
*/
Pkt->InLowMemRetry = FALSE;
}
else
{
Pkt->InLowMemRetry = TRUE;
}
Pkt->LowMemRetry_remainingBufPtr = BufPtr;
Pkt->LowMemRetry_remainingBufLen = Len;
Pkt->LowMemRetry_nextChunkTargetLocation = TargetLocation;
}
/*
* StepLowMemRetry
*
* During extreme low-memory stress, this function retries
* a packet in small one-page chunks, sent serially.
*
* Returns TRUE iff the packet is done.
*/
BOOLEAN StepLowMemRetry(PTRANSFER_PACKET Pkt)
{
BOOLEAN packetDone;
if (Pkt->LowMemRetry_remainingBufLen == 0){
packetDone = TRUE;
}
else {
ULONG thisChunkLen;
if (Pkt->DriverUsesStartIO)
{
/*
* Need the fdoData for the HwMaxXferLen
*/
PFUNCTIONAL_DEVICE_EXTENSION fdoExt = Pkt->Fdo->DeviceExtension;
PCLASS_PRIVATE_FDO_DATA fdoData = fdoExt->PrivateFdoData;
/*
* Need the adapterDesc to limit transfers based on byte count
*/
PCOMMON_DEVICE_EXTENSION commonExtension = Pkt->Fdo->DeviceExtension;
PSTORAGE_ADAPTER_DESCRIPTOR adapterDesc = commonExtension->PartitionZeroExtension->AdapterDescriptor;
ULONG hwMaxXferLen;
/*
* special case: StartIO-based writing must stay serialized for performance
* and proper operations (i.e. sequential writing mode). If need more than
* one transfer to perform this operation, and it's a StartIO-based driver
* (such as CDROM), then just use a single packet and use the retry logic
* that's already built-in to the packet engine. Note that low-mem retry
* cannot be used directly because some write methods do not work if the
* writes are only PAGE_SIZE (i.e. packet writing may corrupt data).
*/
NT_ASSERT(!Pkt->InLowMemRetry);
/*
* We precomputed fdoData->HwMaxXferLen using (MaximumPhysicalPages-1).
* If the buffer is page-aligned, that's one less page crossing so we can add the page back in.
* Note: adapters that return MaximumPhysicalPages=0x10 depend on this to
* transfer aligned 64K requests in one piece.
* Also note: make sure adding PAGE_SIZE back in doesn't wrap to zero.
*/
if (((ULONG_PTR)(Pkt->LowMemRetry_remainingBufPtr) & (PAGE_SIZE-1)) || (fdoData->HwMaxXferLen > 0xffffffff-PAGE_SIZE)){
hwMaxXferLen = fdoData->HwMaxXferLen;
}
else {
NT_ASSERT((PAGE_SIZE%fdoExt->DiskGeometry.BytesPerSector) == 0);
hwMaxXferLen = min(fdoData->HwMaxXferLen+PAGE_SIZE, adapterDesc->MaximumTransferLength);
}
thisChunkLen = MIN(Pkt->LowMemRetry_remainingBufLen, hwMaxXferLen);
}
else {
/*
* Make sure the little chunk we send is <= a page length
* AND that it does not cross any page boundaries.
*/
ULONG bytesToNextPageBoundary;
bytesToNextPageBoundary = PAGE_SIZE-(ULONG)((ULONG_PTR)Pkt->LowMemRetry_remainingBufPtr%PAGE_SIZE);
thisChunkLen = MIN(Pkt->LowMemRetry_remainingBufLen, bytesToNextPageBoundary);
NT_ASSERT(Pkt->InLowMemRetry);
}
/*
* Set up the transfer packet for the new little chunk.
* This will reset numRetries so that we retry each chunk as required.
*/
SetupReadWriteTransferPacket(Pkt,
Pkt->LowMemRetry_remainingBufPtr,
thisChunkLen,
Pkt->LowMemRetry_nextChunkTargetLocation,
Pkt->OriginalIrp);
Pkt->LowMemRetry_remainingBufPtr += thisChunkLen;
Pkt->LowMemRetry_remainingBufLen -= thisChunkLen;
Pkt->LowMemRetry_nextChunkTargetLocation.QuadPart += thisChunkLen;
//
// When running in low-memory stress, always use a partial MDL.
// This allows lower drivers to potentially map a smaller buffer.
//
Pkt->UsePartialMdl = TRUE;
TransferPacketQueueRetryDpc(Pkt);
packetDone = FALSE;
}
return packetDone;
}
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