From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 1/1] scsi: add Synology to 1024 sector blacklist Date: Wed, 13 Jan 2016 10:41:20 +0100 Message-ID: <56961BC0.6090101@redhat.com> References: <1452206045-18332-1-git-send-email-mchristi@redhat.com> <56953DEF.1050306@redhat.com> <1452677624.27508.70.camel@haakon3.risingtidesystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wm0-f67.google.com ([74.125.82.67]:33048 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932963AbcAMJl2 (ORCPT ); Wed, 13 Jan 2016 04:41:28 -0500 Received: by mail-wm0-f67.google.com with SMTP id u188so35806708wmu.0 for ; Wed, 13 Jan 2016 01:41:28 -0800 (PST) In-Reply-To: <1452677624.27508.70.camel@haakon3.risingtidesystems.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Nicholas A. Bellinger" Cc: mchristi@redhat.com, linux-scsi@vger.kernel.org On 13/01/2016 10:33, Nicholas A. Bellinger wrote: >>> This results in IO errors when >>> handling large IOs. This patch just has us use the old 1024 default >>> sectors for this target by adding it to the scsi blacklist. We do >>> not have good contacs with this vendors, so I have not been able to >>> try and fix on their side. >> >> IIRC I saw similar problems a >> couple years ago with LIO because iscsit_map_iovec maps everything a >> page at a time and produced too large an iovec for the underlying >> storage. I'm afraid you're going to get this for pretty much every user >> of LIO. > > Two points here. > > We've been exposing backend dev->dev_attrib.hw_max_sectors settings for > block limits EVPD for FILEIO based on iov limits, and IBLOCK based on > queue_max_hw_sectors() for some time now. > > So initiators that honor block limits EVPD will work as expected. What I was describing is more like the backend request_queue's queue_max_segments influencing the backend's hw_max_sectors. Is that covered as well? Paolo