ULONG
MmGetMdlByteOffset(
IN PMDL Mdl
);
MmGetMdlByteOffset returns the byte offset within a page of the buffer described by a given MDL.
MmGetMdlByteOffset returns the offset in bytes.
Callers of MmGetMdlByteOffset can be running at any IRQL. Usually, callers are running at IRQL <= DISPATCH_LEVEL.