From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 3/3] dm mpath: add support for using previously attached scsi_dh Date: Tue, 08 May 2012 18:20:45 +0200 Message-ID: <4FA947DD.8060908@suse.de> References: <1336447147-3830-1-git-send-email-snitzer@redhat.com> <1336447147-3830-2-git-send-email-snitzer@redhat.com> <4FA8BBA3.3030705@suse.de> <20120508140541.GB8383@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20120508140541.GB8383@redhat.com> Sender: linux-scsi-owner@vger.kernel.org To: Mike Snitzer Cc: dm-devel@redhat.com, agk@redhat.com, babu.moger@netapp.com, sekharan@us.ibm.com, linux-scsi@vger.kernel.org List-Id: dm-devel.ids On 05/08/2012 04:05 PM, Mike Snitzer wrote: > On Tue, May 08 2012 at 2:22am -0400, > Hannes Reinecke wrote: > >> On 05/08/2012 05:19 AM, Mike Snitzer wrote: >>> Use the previously attached scsi_dh if "default" is provided as the >>> hardware handler name (the new 'use_default_hw_handler' flag is set= in >>> the multipath structure). >>> >>> Leverage scsi_dh_attach's ability to increment the scsi_dh's refere= nce >>> count if the same scsi_dh name is provided when attaching -- curren= tly >>> attached scsi_dh name is determined with scsi_dh_attached_handler_n= ame. >>> >> Not sure it that's the correct way. >> >> Using 'default' as the hardware handler name has the drawback that >> the original information (ie the original hardware handler name) >> is lost. > > BTW, on this point: How is the original handler's name lost with my > patches? I set m->hw_handler_name to the original (aka attached) > handler's name (as returned scsi_dh_attached_handler_name). > > "default" is only used as a key to trigger the use of the attached > handler (it causes m->use_default_hw_handler to be set). > What I meant is that within multipath you can only specify one hardware= =20 handler. So if it's 'default' and no hardware handler is attached we=20 wouldn't know what to look for. > Was my description or code somehow unclear? Guess so... otherwise I'= d > not be clarifying this... unfortunately I'm not seeing where I fell > short. > Meanwhile I've sent the patchset, Please check that for details. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: Markus Rex, HRB 16746 (AG N=FCrnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html