From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Wise Subject: Re: [PATCH v2] RDMA/CMA: fix iWARP adapter TCP port space usage Date: Wed, 23 Jun 2010 13:46:47 -0500 Message-ID: <4C225697.6060702@opengridcomputing.com> References: <4C225078.6050001@opengridcomputing.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Roland Dreier Cc: Bernard Metzler , "Tung, Chien Tin" , Jason Gunthorpe , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Peter P Waskiewicz Jr List-Id: linux-rdma@vger.kernel.org Roland Dreier wrote: > > Roland, do you think the iSCSI approach is a "good design" for iWARP > > devices? > > Well, it's a different problem since as I said the port collision > problem is a non-issue for iSCSI anyway. But yes having a separate > interface to assign an iWARP IP address to an RNIC does seem to avoid > the immediate problem. > > I actually don't know what the right answer is -- having a separate IP > address for iWARP does seem to lead to having to duplicate everything > for configuring it. (And this is the approach for the cxgb[34] iSCSI > drivers, right?) > > Yes. Perusing the drivers/scsi/cxgb3i code I see the iscsi ipaddr is actually stored in the port_info struct which is hung of the netdev_priv of the cxgb3 device. It is set by cxgb3i_host_set_param() which is part of the iscsi transport interface. I just think the customer looses when we add iwarp-specific tools, ipaddrs, subnets, etc etc. And what about software iwarp? Will it use the host stack tools and not these new tools? So then we end up with 2 sets of tools for iwarp devices. :( > On the other hand trying to hook offloaded iWARP into the normal stack > does seem to lead to a mess. I see DaveM's point: TCP port space is > just the beginning -- filtering, queueing, etc also have config that > ultimately an offload device would want to hook too. > > Maybe the sanest out of a bad set of options would be to come up with a > standard way to configure independent TCP/IP stacks that share a link. > > really, dunno. > > - R. > -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html