Subject: Re: [RFC PATCH 08/11] IB/Verbs: Use management helper has_iwarp() for, iwarp-check

From: Jason Gunthorpe <[email-masked]>
Date: Fri, 27 Mar 2015 11:29:12 -0600

On Fri, Mar 27, 2015 at 01:16:31PM -0400, ira.weiny wrote:
> On Fri, Mar 27, 2015 at 10:13:19AM -0600, Jason Gunthorpe wrote:
> > On Fri, Mar 27, 2015 at 04:47:36PM +0100, Michael Wang wrote:
> > > 
> > > Introduce helper has_iwarp() to help us check if an IB device
> > > support IWARP protocol.
> > 
> > Should probably be !has_rdma_read_sges()
> > 
> > True if the device can handle more than one SGE entry on a RDMA READ
> > work request.
> 
> Isn't this value already provided by the query_device verb?
> 
> The verbs spec states the Query HCA contains the:
> 
> "Maximum number of scatter/gather entries per Work Request supported by the
> HCA."

http://www.spinics.net/lists/linux-rdma/msg22565.html

''Unlike IB, the iWARP protocol only allows 1 target/sink SGE in an
rdma read''

It is one of those annoying verbs is different on iWarp things.

So the max sge in the query_verbs must only apply to send/rdma write
on iWarp?

Jason