[openib-general] Reserved L_Key API

[Roland Dreier]

    Roland> I don't think consumers ever really want to pass remote
    Roland> entities an R_Key with translation off (which would allow
    Roland> RDMA to arbitrary addreses).  I think the solution for
    Roland> creating R_Keys is FMRs (either Tavor-style or verbs
    Roland> extension-style).

    Fabian> Are the ramifications of such an RKEY any worse than those
    Fabian> of locally attached DMA-capable adapters?  If your FC HBA
    Fabian> goes haywire and decides to write all over memory, there's
    Fabian> not much you can do.  SRP just uses IB as a bus extension
    Fabian> of sorts.

All I can say is that in the real world people don't like it.  That's
why features like remote invalidate get added.

 - R.