From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755917Ab0IFVxG (ORCPT ); Mon, 6 Sep 2010 17:53:06 -0400 Received: from moutng.kundenserver.de ([212.227.17.10]:59853 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752196Ab0IFVxA (ORCPT ); Mon, 6 Sep 2010 17:53:00 -0400 Message-ID: <4C85629D.90101@vlnb.net> Date: Tue, 07 Sep 2010 01:52:29 +0400 From: Vladislav Bolkhovitin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.10) Gecko/20100527 Thunderbird/3.0.5 MIME-Version: 1.0 To: "Nicholas A. Bellinger" CC: James Bottomley , Dirk Meister , linux-scsi@vger.kernel.org, Chetan Loke , Chetan Loke , scst-devel , linux-kernel@vger.kernel.org, Mike Christie , FUJITA Tomonori Subject: Re: [Scst-devel] Fwd: Re: linuxcon 2010... References: <594039.74663.qm@web111905.mail.gq1.yahoo.com> <1282144271.3035.31.camel@mulgrave.site> <1282148296.3035.49.camel@mulgrave.site> <4C6C1D70.7020502@vlnb.net> <41A1E2691BBB412BADCDE5F515CD8EDA@usish.com.cn> <8A96806D-6CD7-44AD-8A9D-143C098C95A4@uni-paderborn.de> <1282256949.30453.278.camel@haakon2.linux-iscsi.org> <4C701E08.2020005@vlnb.net> <1282423398.3015.39.camel@mulgrave.site> <4C73DA15.2010207@vlnb.net> <1282661876.2993.20.camel@mulgrave.site> <4C7421FB.2060007@vlnb.net> <1282685014.32007.51.camel@haakon2.linux-iscsi.org> <4C76CA57.3050405@vlnb.net> <1282857806.32007.175.camel@haakon2.linux-iscsi.org> <4C79484B.3090607@vlnb.net> <1283028468.32007.357.camel@haakon2.linux-iscsi.org> <4C7C18CE.5020103@vlnb.net> <1283204792.32007.448.camel@haakon2.linux-iscsi.org> <4C7FFD1A.8090509@vlnb.net> <1283459158.5598.143.camel@haakon2.linux-iscsi.org> In-Reply-To: <1283459158.5598.143.camel@haakon2.linux-iscsi.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: V02:K0:xBz7W1APtBxYO6X09QaN2JUHUwUdW0ty/VcLzhgc8Wa /cZlgmXpklCwq2flxVEMfZM8SjZFe7enqMiotZzCghcmrcLN11 OmoQOR/Or+kb/nCQlIQjB8oHE7oWAkvb5rXisI86f+utvw0UXz 05zEv8MNaynOI+7t+VzOa53nRKiB9BY+efUVw8OKSzfzsNoflU 2j8gjzwuXldTaKF5MUfCw== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nicholas A. Bellinger, on 09/03/2010 12:25 AM wrote: >>> Again, I still have no idea what you are trying to conjour up. The >>> passthrough for STGT compatibility with TCM_Loop via SG_IO and BSG has >>> already been merged by Tomo-san into tgt.git. Futhermore, we are using >>> the same TCM_Loop high level multi-fabric WWPN emulation together with >>> new (and old) QEMU HBA emulation into KVM guest using SG_IO and BSG as >>> well. >> >> The patches were good, but don't mislead people about that. For sake of >> clearness, what you called "the passthrough for STGT compatibility with >> TCM_Loop via SG_IO and BSG" has nothing with LIO/TCM_Loop. What merged >> fixed problems STGT had in the pass-through implementation. It at the >> same time fixed problems with SCST's scst_local, so similarly can be >> called "the passthrough for STGT compatibility with scst_local via SG_IO >> and BSG". >> > > Uh, I don't think TCM_Loop and scst_local are exactly comparable at this > point. TCM_Loop supports high level multi-fabric WWPN emulation that > allows it to work transparently with inter-nexus SPC-4 PR operation. > Therefore, using TCM_Loop, STGT userspace fabrics now support both PR > and ALUA emulation from TCM_Loop LUNs. This is done at struct > config_group_ops->make_group() time to report $PROTO_IDENT and the > necessary WWPN info to TCM Core logic. TCM_Loop also uses the fabric > indepent configfs handlers for pretty much all of it's control plane > code. TCM_Loop and scst_local are exactly comparable and do absolutely the same thing. If you see any difference, please be precise. Internal implementation doesn't matter as soon as it doesn't affect the functionality STGT uses. >> I have no doubts in benefits to TCM. But I have asked about benefits >> _for an average user_. STGT already can do what you listed above. >> > > Again, from above how it benefits users: > > 1) a userspace library in intrepted languages and 2) create high level > applications using said userspace libraries that allow compatiblity to > be contained in the lib below. > > 2) create high level applications using said userspace libraries that > allow compatiblity to be contained in the lib. All those can be done for STGT. LIO isn't needed for that. So, value for STGT users still not questionable to me. Vlad