[openib-general] Re: [PATCH] ib_mad: prevent duplicateoutstanding MADtransactions with same TID

[Sean Hefty]

Michael S. Tsirkin wrote:
> Sorry for being dense, I'm not sure I understand.  Do you mean response when you
> say receive? We never have both a request and a response outstanding to the
> same remove GID with the same TID, do we?

I was meaning:

Request - response bit is 0
Response - response bit is 1
Send - outgoing MAD (may be request or response)
Receive - incoming MAD (may be request or response)

In your example, you had host A sending a request to B (I'll call transaction 
1), and host B sending a request to A (transaction 2).  Host A has one request 
being sent, and another being received.  An ACK from B to A must match with 
transaction 1.  A NACK from B to A can match with either transaction.

To match NACKs using the response bit implies that requests can only flow one 
direction, and responses the other.  This adds a policy that I don't think 
should be part of the general MAD layer code.

- Sean