[RFC] Move InfiniBand .h files

[Roland Dreier <rolandd@cisco.com>]

I would like to get people's reactions to moving the InfiniBand .h
files from their current location in drivers/infiniband/include/ to
include/linux/rdma/.  If we agree that this is a good idea then I'll
push this change as soon as 2.6.14 starts.

The advantages of doing this are:

  - The headers become more easily accessible to other parts of the
    tree that might want to use IB support.  For example, an NFS/RDMA
    client probably wants to live under fs/
  - It makes it easier to build IB modules outside the tree, since
    include/linux gets put in /lib/modules/<ver>/build.  I realize
    that we don't really care about out-of-tree modules, but it is
    convenient to be able to develop and distribute new drivers that
    build against someone's existing kernels.
  - We can kill off the ugly

        EXTRA_CFLAGS += -Idrivers/infiniband/include

    lines in our Makefiles.

The disadvantages are:

  - It's churn with little technical merit.
  - It makes it a little harder to pull the OpenIB svn tree into a
    kernel tree, since one would have to link both drivers/infiniband
    and include/linux/rdma instead of just drivers/infiniband.  This
    problem goes away if/when OpenIB shifts over to a new source code
    control system.

Thanks,
  Roland