[ofa-general] [PATCH RFC] RDMA/cxgb3: Fixes for zero-stag.

[Roland Dreier]

 > > How about enhancing the iWARP HW drivers implementation of
 > > get_dma_mr to switch on the access flags provided by the caller, and
 > > if no remote access it needed, just return zero stag for mr.lkey
 > > without doing any registration.

 > I think that sounds reasonable.  I can add that for chelsio.

that makes some sense although I don't know of any code that uses the
zero STag or ib_get_dma_mr() with only local permissions to be honest,
with the exception of IPoIB, which of course has no relevance to iwarp.

Also using the zero STag breaks the semantics slightly in that there is
no longer any PD attached to the key returned by ib_get_dma_mr().

Another point to note is that IB has the analogous concept of "reserved
L_Key" which we could expose if anyone actually cared.

 - R.