[openib-general] Reserved L_Key API

[Roland Dreier]

    Fabian> Since we need an input PD anyway, I suggest having a call
    Fabian> like:

    Fabian> struct ib_mr *ib_reg_dma_mr(struct ib_pd *pd, int
    Fabian> mr_access_flags );

    Fabian> Depending on the mr_access_flags, the returned MR could
    Fabian> have a valid RKEY with PD enforcement.  If only local
    Fabian> access is needed, the LKEY could be the reserved LKEY if
    Fabian> the device supports it.  This would enable both your
    Fabian> desired usage as well as future usage by kernel clients
    Fabian> that perform RDMA.  With the above call, I think
    Fabian> ib_reg_phys_mr can be eliminated.

Thinking about this some more, I don't have a problem with adding the
mr_access_flags.  However I think reg_phys_mr is still required,
because it allows things like combining multiple buffers into a single
virtually contiguous region and setting the IO virtual address (and
will be needed to implement userspace memory registration anyway).

 - R.