[openib-general] RFC: detecting duplicate MAD requests

[Sean Hefty]

Michael S. Tsirkin wrote:
> Another concern with this approach: consider an application that accepts
> incoming MAD requests and drops some of them.  With current code it can do this
> safely and remote side will retry. With the duplicate tracking in umad module
> that you propose, MAD will stay in the list forever, and application will never
> again get called.

This is why I proposed a timeout for responses.

> This kind of subtle behaviour change seems to me worse than outright ABI
> breakage.

If everyone is okay with breaking the ABI, then I would add send completion 
notification to umad, and put the responsibility on callers not to generate 
duplicate responses.

- Sean