[openib-general] new IB CM reject reason

[Sean Hefty]

> No, I don't think "application crashed" makes sense as an element of wire protocol.
> I think an optional logging of errors in kernel CM would be a much better
> solution. I know I had to add some printks it each time I was debugging SDP.

The "application crashed" scenario is what high-lighted the issue.  The problem 
is that the CM must provide a reject reason.  Which reject reason do you use? 
My suggestion was for a reject reason of other/unknown/none given (pick one).

> 2. Another objection is that this feature seems to invite misuse where applications
> will use REJ reason as a hint on whether remote side crashed. But REJ could be
> lost. Wouldn't this confuse the remote side?

Currently, the CM issues the reject using "consumer defined", since nothing else 
maps any better under this condition.  But the reject isn't consumer defined... 
  By doing this, an application that expects specific private data in the reject 
message won't find it, which is just as likely to confuse the remote side.  This 
is why I think an unknown/unspecified reject reason is needed.

How an application interprets a reject with 'unknown' reason is up to the 
application, but I do think this is better than the application trying to guess 
whether 'consumer defined' really does mean consumer defined.

- Sean