[openib-general] [RFC] [PATCH] user_mad: Support RMPP on send side

[Sean Hefty]

Hal Rosenstock wrote:
> The main issue I see on the send side is that without examining the
> header, one can't get all the parameters for ib_create_send_mad. Even
> with some variant of this call (perhaps broken up into 2 parts), I think
> the mad_agent is the key parameter needed. I don't see a way to get this
> ahead of time without 2 copies. Am I then back to not using this routine
> and doing it "by hand" ?

Why not copy down the ib_user_mad, or any necessary header information, 
separately from the actual MAD data itself?  I.e. read in the mad_agent and 
MAD length first, allocate the send MAD, and then copy the data.  (I'll 
admit that I'm not overly familiar with this code, so if this is overly 
difficult just say so...)

I'm concerned about having excessive copies on the opensm node, especially 
if it's sending a large number of RMPP packets.

- Sean