Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756811Ab2BGTxZ (ORCPT ); Tue, 7 Feb 2012 14:53:25 -0500 Received: from kamaji.grokhost.net ([87.117.218.43]:36776 "EHLO kamaji.grokhost.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755937Ab2BGTxY (ORCPT ); Tue, 7 Feb 2012 14:53:24 -0500 Message-ID: <4F318131.7020004@bootc.net> Date: Tue, 07 Feb 2012 19:53:21 +0000 From: Chris Boot User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0) Gecko/20111222 Thunderbird/9.0.1 MIME-Version: 1.0 To: Stefan Richter CC: Julian Calaby , Clemens Ladisch , target-devel@vger.kernel.org, linux1394-devel@lists.sourceforge.net, Boaz Harrosh , Andy Grover , linux-scsi@vger.kernel.org, lkml Subject: Re: FireWire/SBP2 Target mode References: <4E4BD560.4010806@bootc.net> <4E4D3B88.30003@ladisch.de> <4F29978A.3010707@redhat.com> <20120201224156.0773ebc6@stein> <4F2A55B9.4040005@panasas.com> <4F2A60DC.9030007@ladisch.de> <4F2FD1F4.9050702@bootc.net> <4F2FE705.3070509@ladisch.de> <4F2FE8DA.70502@bootc.net> <20120206212628.6880c506@stein> <5C167A1D-2203-4F1C-B538-E99DD87E7E42@bootc.net> <476E7976-738A-4202-9FC4-FA5B060EA95F@bootc.net> <4F30D4F6.1040802@bootc.net> <20120207201730.1c8cf6a3@stein> In-Reply-To: <20120207201730.1c8cf6a3@stein> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2139 Lines: 50 On 07/02/2012 19:17, Stefan Richter wrote: > On Feb 07 Chris Boot wrote: >> On 06/02/2012 23:09, Chris Boot wrote: >>> On 6 Feb 2012, at 23:00, Julian Calaby wrote: >>>> Stupid question: Could you use a completion queue or something >>>> equivalent to wait until you have seen the fw_node, *then* process the >>>> LOGIN request? >>> >>> The fw_address_handler callback is called in interrupt context, and >>> I can't sleep from within there. As far as I'm aware I must call >>> fw_send_response() from within the callback and can't defer that until >>> I've scheduled something on a work queue. Please correct me if I'm >>> wrong though, as that might be useful anyway. >> >> Hmm sorry I've thought about this overnight and clearly I was talking >> rubbish. Yes, I need to reply in the fw_address_handler but all I tend >> to do in there is schedule a task to the the main part of the work >> anyway. As most of the operations require fetching an ORB from the >> initiator I have to do this from user context. > > Technically there are two things to perform: > > 1. Finish the inbound IEEE 1394 transaction to the management agent > register by means of fw_send_response(). As far as I can tell, you > don't have to do that in the address_callback(). But there is little > reason not to. > > fw_send_response() ends the lifetime of an fw_request, so read the > speed code before you respond. > > 2. Finish the inbound SBP-2 transaction; here the login. This and > everything that leads up to it is definitely easiest to implement in > a process context, e.g. workqueue item. Yep I do exactly that - I save the speed then schedule_work() inside the address callback, then call fw_send_response() still within the callback. The work callback uses fw_run_transaction() to fetch the ORB and deal with it. Cheers, Chris -- Chris Boot bootc@bootc.net -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/