[openib-general] [PATCH] user_mad: Add receive side RMPP support

[Sean Hefty]

Roland Dreier wrote:
> I understand and agree with the sentiment of not wanting to add
> another ioctl() to get the length.  Instead, how about returning a
> ib_user_mad_hdr with a status of ENOSPC and putting the actual length
> somewhere.  I'm not sure if it's better to change the ABI and add a
> length field to ib_user_mad_hdr, or if we want to return the first 36
> bytes of an RMPP MAD so the user can figure out the correct length.

Unless the MAD layer modifies the received MAD, the length may not be set in 
the header.  Setting this doesn't seem like a big deal.  If it is set, then 
I'm guessing that we'd want to set the PayloadLength to the value indicated 
by the spec, but that's not the easiest value to use in order to determine 
the size of the read.

Given that, I think that it makes more sense to add a length field to the 
ib_user_mad_hdr.

- Sean