[openib-general] RFC: detecting duplicate MAD requests

[Sean Hefty]

>Well the ACK for the direction switch is special, isn't it?
>All I'm saying, let's pass it up to the application.

I really don't think that this is the direction that we want to take the
interface.  A multithreaded application could see the ACK before the request.
Multiple ACKs could be received for the same request, or no ACK could be
received at all.  This pushes timeout handling and duplicate detection up to the
any application using DS RMPP.  We should work for a simpler interface,
especially one exposed to userspace.

Let's start with an interface that's efficient and works well in the kernel, and
then determine how to expose that interface up to userspace.  Let's try to keep
the complexity in one location.

Btw, it looks like Jack's patch has the MAD layer read MAD data while it is in
transfer.  I don't think that we can do this while the data is mapped.

- Sean