irplist.cpp

pci 底层驱动

//
//  File:   irplist.cpp
//  Description: implementation of class IrpList
//
//  Created:  Wed. Jan 15, 2003
//
//
// Copyright and Disclaimer:
//
//   ---------------------------------------------------------------
//   THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
//   EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
//   IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
//   PARTICULAR PURPOSE.
//
//   IN NO EVENT SHALL CONEXANT BE LIABLE TO ANY PARTY FOR DIRECT,
//   INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
//   INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE
//   AND ITS DOCUMENTATION, EVEN IF CONEXANT HAS BEEN ADVISED OF THE
//   POSSIBILITY OF SUCH DAMAGE.
//
//   Copyright (c) 2000-2001 Conexant Systems, Inc.
//
//   All Rights Reserved.
//   ---------------------------------------------------------------
//
// Module Revision Id:
//
//

#include "common.h"
#include "irplist.h"

/////////////////////////////////////////////////////////////////////////////////////////
//IrpList::IrpList (constructor)
//
// Initializes the list head and spinlock so that the list will be ready to use.
//
IrpList::IrpList()
{
    KeInitializeSpinLock (&_spin_lock);
    InitializeListHead (&_list_head);
}

/////////////////////////////////////////////////////////////////////////////////////////
//IrpList::add
//
// Adds an IRP to the tail of the list
//
VOID IrpList::add(PIRP p_irp)
{
    PLIST_ENTRY p_list_entry = &p_irp->Tail.Overlay.ListEntry;

    KIRQL old_irql;
    KeAcquireSpinLock (&_spin_lock, &old_irql);

    InsertTailList (&_list_head, p_list_entry);

    KeReleaseSpinLock (&_spin_lock, old_irql);
}

/////////////////////////////////////////////////////////////////////////////////////////
//IrpList::remove
//
// Removes an IRP from the head of the list
//
PIRP IrpList::remove()
{
    PIRP p_irp = NULL;

    KIRQL old_irql;
    KeAcquireSpinLock (&_spin_lock, &old_irql);

    if (!IsListEmpty(&_list_head)) 
    {
        PLIST_ENTRY p_list_entry = RemoveHeadList(&_list_head);
        p_irp = (PIRP) ((PUCHAR)p_list_entry - FIELD_OFFSET(IRP, Tail.Overlay.ListEntry));
    }
    
    KeReleaseSpinLock (&_spin_lock, old_irql);

    return p_irp;
}

/////////////////////////////////////////////////////////////////////////////////////////
//IrpList::remove
//
//Removes a specific IRP from the list.  Returns TRUE if the 
// IRP was in the list
//
BOOLEAN IrpList::remove(PIRP p_irp)
{
    //Get the list entry from the IRP
    PLIST_ENTRY p_list_entry = &p_irp->Tail.Overlay.ListEntry;
    BOOLEAN  found = FALSE;
    
    KIRQL old_irql;
    KeAcquireSpinLock (&_spin_lock, &old_irql);

    // Loop through the linked list checking for the IRP's entry.
    PLIST_ENTRY p_current_entry = _list_head.Flink;
    while (p_current_entry != &_list_head) 
    {
        if(p_current_entry == p_list_entry)
        {
            //The IRP was found in the list.  Remove it.
            RemoveEntryList(p_list_entry);
            found = TRUE;
            break;
        }
        p_current_entry = p_current_entry->Flink;
    }

    KeReleaseSpinLock (&_spin_lock, old_irql);

    return found;
}