From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: Converting from RC to UC Date: Fri, 11 Mar 2011 11:58:31 -0700 Message-ID: <20110311185831.GX22729@obsidianresearch.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Alan Cook Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org On Fri, Mar 11, 2011 at 06:29:19PM +0000, Alan Cook wrote: > I currently have a working RDMA InfiniBand based client-server application using > Reliable Connection (RC) service. I would like to change the application to use > Unreliable Connection (UC) service. I am not performing RDMA reads, so I should > be able to use UC. > > I was under the impression that the only change that would be required would be > changing the queue pair type from IBV_QPT_RC to IBV_QPT_UC. After making this > change on both the client and server applications, I receive an Invalid > Parameter error from rdma_accept() on the server side of the application. The > client side reports no errors (other than the rejected server connection). > > Internet searches have not been fruitful, as it seems most people are using RC > rather than UC. > > What else needs to be changed in the setup for switching from RC to UC? I think what you are hitting is some code is calling ibv_modify_qp with an invalid qp_attr_mask for one of the state transitions. UC and RC have different requirements. Assuming you are not calling ibv_modify_qp in your app it is probably a kernel bug? Jason -- 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