From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 3/4] scsi: improved eh timeout handler Date: Mon, 10 Jun 2013 07:48:03 +0200 Message-ID: <51B56893.6040803@suse.de> References: <1370511835-50072-1-git-send-email-hare@suse.de> <1370511835-50072-4-git-send-email-hare@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from cantor2.suse.de ([195.135.220.15]:58995 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750997Ab3FJFsN (ORCPT ); Mon, 10 Jun 2013 01:48:13 -0400 In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Baruch Even Cc: James Bottomley , linux-scsi , Joern Engel , Ewan Milne , James Smart , Ren Mingxin , Roland Dreier , Bryn Reeves , Christoph Hellwig On 06/10/2013 02:12 AM, Baruch Even wrote: > On Thu, Jun 6, 2013 at 12:43 PM, Hannes Reinecke wrote= : >> When a command runs into a timeout we need to send an 'ABORT TASK' >> TMF. This is typically done by the 'eh_abort_handler' LLDD callback. >> >> Conceptually, however, this function is a normal SCSI command, so >> there is no need to enter the error handler. >> >> This patch implements a new scsi_abort_command() function which >> invokes an asynchronous function scsi_eh_abort_handler() to >> abort the commands via 'eh_abort_handler'. >> >> If the 'eh_abort_handler' returns SUCCESS or FAST_IO_FAIL the >> command will be retried if possible. If no retries are allowed >> the command will be returned immediately, as we have to assume >> the TMF succeeded and the command is completed with the LLDD. >> For any other return code from 'eh_abort_handler' the command >> will be pushed onto the existing SCSI EH handler, or aborted >> with DID_TIME_OUT if that fails. >> >=20 > Why would you do a retry at this low level? We already have a bad pat= h, > the IO may already be rerouted through another path and continuing wi= th this > IO here may interfere with the multipath handling. >=20 =46or multipathing no retries would be set, so the command would be returned immediately. I checked. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=C3=BCrnberg GF: J. Hawn, J. Guild, F. Imend=C3=B6rffer, HRB 16746 (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