[PATCH] nvme-rdma: Support 2 inline data SGEs for write commands.

[swise@opengridcomputing.com (Steve Wise)]

> >
> > This looks fine to me in general, but I'm a little curious how your arrived
at
> > that 2 number.  Why not 4 or 8?
> 
> Some adapters doesn't support more than 5 sges. So increasing it to 4 or 8
would
> fail them.
> Chuck reported 1 out of 3 adapters only support 3. Its likely due to
min(send_sge,
> recv_sge).
> With total of 3 SGEs (64B cmd sge + data sges), WQE fits in 64 bytes size at
the
> provider driver level. So to strike balance between cache line usage and
> performance, and to be nice to those adapters which has low SGE (either due to
> min(send_sge, recv) or other otherwise, I picked 2 data sges.
> 
> Side  note: I have split out send and recv sge in other unrelated patch which
is in
> review internally from linux-rdma tree.

I'm looking forward to this patch since cxgb4 has max_recv_sge of 4 and
max_send_sge of 17!

Steve.