From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: Request for review of Linux iSCSI driver version 4.0.0.1 Date: 05 Dec 2003 10:33:09 -0500 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <1070594036.1603.34.camel@mulgrave> References: <200310231734.10263.krmurthy@cisco.com> <200312011740.09693.krmurthy@cisco.com> <1070292174.2007.14.camel@mulgrave> <200312041800.55663.krmurthy@cisco.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from nat9.steeleye.com ([65.114.3.137]:28422 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S264591AbTLEPeC (ORCPT ); Fri, 5 Dec 2003 10:34:02 -0500 In-Reply-To: <200312041800.55663.krmurthy@cisco.com> List-Id: linux-scsi@vger.kernel.org To: "N.C.Krishna Murthy" Cc: Christoph Hellwig , SCSI Mailing List , davmyers@cisco.com On Thu, 2003-12-04 at 07:30, N.C.Krishna Murthy wrote: > Having user level utility trigger the rescan thru sysfs interfaces will call > scsi_scan() which will inturn call scsi_scan_host_selected(). > Instead wouldn't it be preferable to call scsi_scan_host_selected() > from the iSCSI driver itself? Well, consider all the ramifications: what happens if the reconfiguration is deleting an existing LUN with a mounted filesystem? What happens if the user wants to do something with the new LUN as soon as it appears (like fold it into a VM volume, or format it). The hotplug system is designed to propagate events that others might be interested in, which it strikes me this is. So, if you have to trigger a hotplug event anyway, you may as well go the whole hog and do the reconfiguration as part of the hotplug subsystem. > > We could do with a generic infrastructure within SCSI for generating > > these events, anyway, if you want to go that route... > > > I am not much familiar with SCSI hotplug. > > If the generic infrastructure which you mentioned does not exist now and in > case there is a plan to do one such thing is there any framework for that? > Wouldn't that require a kernel API which is capable of both > "adding new luns" and "deleting luns which no longer exist"? Well, a hotplug event feeds certain information into the environment when it triggers the call. All we really need is a wrapper in SCSI to add the SCSI information to the environment and trigger the event in a generic fashion. James