From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kashyap Desai Subject: RE: Scsi Error handling query Date: Mon, 30 Mar 2015 17:15:41 +0530 Message-ID: References: <5d00e10b067fd4d0fb82ecdec18dd325@mail.gmail.com> <55142C6D.1060205@suse.de> <55157F08.3070707@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-wi0-f182.google.com ([209.85.212.182]:37790 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751398AbbC3Lpo convert rfc822-to-8bit (ORCPT ); Mon, 30 Mar 2015 07:45:44 -0400 Received: by wiaa2 with SMTP id a2so125524554wia.0 for ; Mon, 30 Mar 2015 04:45:43 -0700 (PDT) In-Reply-To: <55157F08.3070707@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke , linux-scsi@vger.kernel.org > -----Original Message----- > From: Hannes Reinecke [mailto:hare@suse.de] > Sent: Friday, March 27, 2015 9:32 PM > To: Kashyap Desai; linux-scsi@vger.kernel.org > Subject: Re: Scsi Error handling query > > On 03/26/2015 07:43 PM, Kashyap Desai wrote: > >> -----Original Message----- > >> From: Hannes Reinecke [mailto:hare@suse.de] > >> Sent: Thursday, March 26, 2015 9:28 PM > >> To: Kashyap Desai; linux-scsi@vger.kernel.org > >> Subject: Re: Scsi Error handling query > >> > >> On 03/26/2015 02:38 PM, Kashyap Desai wrote: > >>> Hi Hannes, > >>> > >>> I was going through one of the slide posted at below link. > >>> > >>> http://events.linuxfoundation.org/sites/events/files/slides/SCSI-= EH. > >>> pd > >>> f > >>> > >>> Slide #59 has below data. I was trying to correlate with latest > >>> upstream code, but do not understand few things. Does Linux handl= e > >>> blocking I/O to the device and target before it actually start > >>> legacy EH > >> recovery ? > >> > >> Yes. This is handled by 'scsi_eh_scmd_add()', which adds the comma= nd > >> to the internal 'eh_entry' list and starts recovery once all > >> remaining outstanding commands are completed. > > > > Thanks Hannes..! Scsi_eh_scmd_add() move shost state to recovery, s= o > > it means blocking further IO to the Host and not really a limited = to > > Device/Target for which command was timed out. Right ? > > I understood that, new improvement of scsi error handling will allo= w > > IOs to the other Devices attached to the host except the IO belongs= to > > specific target. > > > > Also, one more thing to clarify... In presentation, term "task set > > aborts" > > was used. Does this mean task set abort is handled as traversing > > complete list of timed out command and sending individual TASK ABOR= T ? > > > No. The idea was to send 'task set aborts' as a single TMF. Thanks Hannes.! OK so idea was to have single TMF for "Task set abort.= " I am not sure how to frame my next question.. But what if Linux SCSI lay= er traverse each IO of one particular target and issue individual Task abo= rt? Don=E2=80=99t we call that as "task set aborts" ? How LLD Driver shoul= d interface for "task set aborts" as single TMF ? My understanding is "Task set abo= rt" will be internally converted to single Task abort either by SCSI layer = or HBA FW. > However, I'm not sure if I'll be going ahead with that one; once we'v= e > issued a > 'transport reset the commands will be cone anyway. > > Cheers, > > Hannes > -- > Dr. Hannes Reinecke zSeries & Storage > hare@suse.de +49 911 74053 688 > SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N=C3=BCrnberg > GF: F. Imend=C3=B6rffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton= HRB 21284 > (AG > N=C3=BCrnberg) -- 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