RE: [PATCH RFC 2/2] RDMA/isert: Support iWARP transport

Steve Wise
2015-06-25T18:33:33Z

> -----Original Message-----
> From: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Hefty, Sean
> Sent: Thursday, June 25, 2015 1:30 PM
> To: Jason Gunthorpe; Steve Wise
> Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org; orgerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org; raid-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org
> Subject: RE: [PATCH RFC 2/2] RDMA/isert: Support iWARP transport
>
> > > + * IWARP transports need REMOTE_WRITE for MRs used as the target of
> > > + * an RDMA_READ. Since the DMA MR is used for all ports, then if
> > > + * any port is running IWARP, add REMOTE_WRITE.
> > > + */
> > > + if (any_port_is_iwarp(device))
> >
> > It would be nice to have a new-style cap test for this instead of open
> > coding iwarp. Similar to rdma_cap_read_multi_sge
>
> This should be pushed down into the devices, or at least within verbs, rather than having ULPs needing to know this oddness.

How would you envision doing this? At the time a MR is registered the device driver doesn't know if the application will be doing
RDMA reads or not on that MR.

Steve.