fxmemorybufferfrompool.cpp

Go to the documentation of this file.

/*++
 
Copyright (c) Microsoft Corporation
 
Module Name:
 
    FxMemoryBufferFromPool.cpp
 
Abstract:
 
    This module implements a frameworks managed FxMemoryBufferFromPool
 
Author:
 
 
Environment:
 
    kernel mode only
 
Revision History:
 
--*/
 
#include "coreprivshared.hpp"
 
FxMemoryBufferFromPool::FxMemoryBufferFromPool(
    __in PFX_DRIVER_GLOBALS FxDriverGlobals,
    __in size_t BufferSize
    ) :
    FxMemoryObject(FxDriverGlobals, sizeof(*this), BufferSize)
/*++
 
Routine Description:
    Constructor for this object.
 
Arguments:
    BufferSize - The buffer size associated with this object
 
Return Value:
    None
 
  --*/
{
    m_Pool = NULL;
}
 
FxMemoryBufferFromPool::FxMemoryBufferFromPool(
    __in PFX_DRIVER_GLOBALS FxDriverGlobals,
    __in size_t BufferSize,
    __in USHORT ObjectSize
    ) :
    FxMemoryObject(FxDriverGlobals, ObjectSize, BufferSize)
/*++
 
Routine Description:
    Constructor for this object.
 
Arguments:
    BufferSize - The buffer size associated with this object
 
    ObjectSize - size of the derived object
 
Return Value:
    None
 
  --*/
{
    m_Pool = NULL;
}
 
FxMemoryBufferFromPool::~FxMemoryBufferFromPool()
/*++
 
Routine Description:
    Destructor for this object.  This function does nothing, it lets
    SelfDestruct do all the work.
 
Arguments:
    None
 
Return Value:
    None
 
  --*/
{
    if (m_Pool != NULL) {
        MxMemory::MxFreePool(m_Pool);
    }
}
 
_Must_inspect_result_
NTSTATUS
FxMemoryBufferFromPool::_Create(
    __in PFX_DRIVER_GLOBALS FxDriverGlobals,
    __in_opt PWDF_OBJECT_ATTRIBUTES Attributes,
    __in POOL_TYPE PoolType,
    __in ULONG PoolTag,
    __in size_t BufferSize,
    __out FxMemoryObject** Buffer
    )
{
    CfxDeviceBase* pDeviceBase;
    FxMemoryBufferFromPool* pBuffer;
    NTSTATUS status;
    BOOLEAN isPaged;
 
    isPaged = FxIsPagedPoolType(PoolType);
 
    if (isPaged) {
        pDeviceBase = FxDeviceBase::_SearchForDevice(FxDriverGlobals,
                                                     Attributes);
    }
    else {
        pDeviceBase = NULL;
    }
 
    //
    // FxMemoryBufferFromPool can handle paged allocation as well.  We only
    // use FxMemoryPagedBufferFromPool if we have an FxDeviceBase that we can use
    // in the dispose path, otherwise these 2 classes are the same.
    //
    if (pDeviceBase != NULL) {
        ASSERT(isPaged);
        pBuffer = new(FxDriverGlobals, Attributes)
            FxMemoryPagedBufferFromPool(FxDriverGlobals, BufferSize, pDeviceBase);
    }
    else {
        pBuffer = new(FxDriverGlobals, Attributes)
            FxMemoryBufferFromPool(FxDriverGlobals, BufferSize);
    }
 
    if (pBuffer == NULL) {
        return STATUS_INSUFFICIENT_RESOURCES;
    }
 
    status = STATUS_SUCCESS;
 
    if (pBuffer->AllocateBuffer(PoolType, PoolTag) == FALSE) {
        status = STATUS_INSUFFICIENT_RESOURCES;
    }
 
    if (!NT_SUCCESS(status)) {
        pBuffer->DeleteFromFailedCreate();
        return status;
    }
 
    if (isPaged) {
        //
        // Callbacks might be a bit excessive (passive dispose is what we are
        // really after) because this object has no callbacks, but this is being
        // proactive in case any callbacks are added.  If they are added, this
        // will take care of them w/out additional changes to object setup.
        //
        pBuffer->MarkPassiveCallbacks(ObjectDoNotLock);
    }
 
    *Buffer = pBuffer;
 
    return STATUS_SUCCESS;
}