[Openib-windows] [PATCH] HCA: Allocate MDLs for memory registrationmanually

[Jan Bottorff]

>Instead of calling IoAllocateMdl to setup the MDL for a memory region,
the >code will manually allocate a buffer large enough for the MDL and
call >MmInitializeMdl instead.
>This is needed to allow buffers that exceed the limits of IoAllocateMdl
to >be registered.  The DDK docs detail the limitations on size of
>IoAllocateMdl.

The buffer size limitation that can be described by an MDL is because
the size field in the MDL structure is only 16-bits (on 32-bit Windows).
The calculation shown in the DDK docs for IoAllocateMdl: