From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH] IB/srp: Fix initiator lockup Date: Wed, 13 Jan 2010 11:16:15 -0700 Message-ID: <20100113181615.GC16490@obsidianresearch.com> References: <20100112232421.GA16490@obsidianresearch.com> 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: Bart Van Assche Cc: Roland Dreier , OFED mailing list , Chris Worley List-Id: linux-rdma@vger.kernel.org On Wed, Jan 13, 2010 at 08:23:27AM +0100, Bart Van Assche wrote: > On Wed, Jan 13, 2010 at 12:24 AM, Jason Gunthorpe > wrote: > > [ ... ] > > > > Also, I couldn't tell for sure from a cursory examination of the > > patch, but the initiator must be designed to not stall processing the > > RQ dependent on the SQ or the credit level, when using a credit scheme > > like this. Or you will deadlock. > > > > For instance it isn't clear to me how the control flow around > > srp_process_cred_req is ment to work - it tries to send a reply, but > > if it can't due to srp_get_txp_iu failing it just gives up forever? > > For a standards-conforming SRP target, srp_get_txp_iu() will never > fail. A quote from section 5.5.2 of the SRP r16a document: What guarantees that that the send completion for the reply is processed before a receive completion for the next request? 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