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/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
deviosup.c
Abstract:
This module implements the memory locking routines for MSFS.
Author:
Manny Weiser (mannyw) 05-Apr-1991
Revision History:
--*/
#include "mailslot.h"
//
// Local debug trace level
//
#define Dbg (DEBUG_TRACE_DEVIOSUP)
#ifdef ALLOC_PRAGMA
#pragma alloc_text( PAGE, MsMapUserBuffer )
#endif
VOID
MsMapUserBuffer (
IN OUT PIRP Irp,
IN KPROCESSOR_MODE AccessMode,
OUT PVOID *UserBuffer
)
/*++
Routine Description:
This routine obtains a usable virtual address for the user buffer
for the current I/O request in the specified mode.
Arguments:
Irp - Pointer to the Irp for the request.
AccessMode - UserMode or KernelMode.
UserBuffer - Returns pointer to mapped user buffer.
Return Value:
None.
--*/
{
AccessMode;
PAGED_CODE();
//
// If there is no Mdl, then we must be in the Fsd, and we can simply
// return the UserBuffer field from the Irp.
//
if (Irp->MdlAddress == NULL) {
*UserBuffer = Irp->UserBuffer;
return;
}
//
// Get a system virtual address for the buffer.
//
*UserBuffer = MmGetSystemAddressForMdl( Irp->MdlAddress );
return;
} // MsMapUserBuffer
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