[openib-general][PATCH][RFC]: CMA IB implementation

[Caitlin Bestler]

> > enum cma_close_flags {
> >       CMA_CLOSE_ABRUPT = 0,
> >       CMA_CLOSE_GRACEFUL
> > };
> 
> Not sure what these are for.  Why not have the user always destroy the cma_id?
> If it hasn't yet been destroyed when a disconnect comes in, callback the user.
> If a connection hasn't been disconnected when it is destroyed, automatically
> send a disconnect message.
> 

DAT defines a graceful close as one that occurs *after*
any work requests already posted to the send queue
have had a chance to complete normally. It serves the
same application layer purpose as half-closing a socket.

While this may be a somewhat advanced option for a
low level interface there are advantages to letting the
verb layer implement it. The device dependent code
may have options available that will allow the graceful
close to be issued promptly after the currently newest
work request already posted to the QP.

However it can be, and has been, implemented above
the verb layer by the DAT Provider without device
specific support.