From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out4-smtp.messagingengine.com ([66.111.4.28]:54529 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751235AbdEDTdw (ORCPT ); Thu, 4 May 2017 15:33:52 -0400 Date: Thu, 4 May 2017 12:33:42 -0700 From: Greg KH To: Stephen Hemminger Cc: stable@vger.kernel.org, Stephen Hemminger , "Martin K . Petersen" Subject: Re: [PATCH] scsi: storvsc: Workaround for virtual DVD SCSI version Message-ID: <20170504193342.GB5095@kroah.com> References: <20170503225632.19961-1-sthemmin@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170503225632.19961-1-sthemmin@microsoft.com> Sender: stable-owner@vger.kernel.org List-ID: On Wed, May 03, 2017 at 03:56:32PM -0700, Stephen Hemminger wrote: > From: Stephen Hemminger > > commit f1c635b439a5c01776fe3a25b1e2dc546ea82e6f upstream > > Hyper-V host emulation of SCSI for virtual DVD device reports SCSI > version 0 (UNKNOWN) but is still capable of supporting REPORTLUN. > > Without this patch, a GEN2 Linux guest on Hyper-V will not boot > successfully with virtual DVD ROM device. What happens is that the SCSI > scan process falls back to doing sequential probing by INQUIRY. But the > storvsc driver has a previous workaround that masks/blocks all errors > reports from INQUIRY (or MODE_SENSE) commands. This workaround causes > the scan to then populate a full set of bogus LUN's on the target and > then sends kernel spinning off into a death spiral doing block reads on > the non-existent LUNs. > > By setting the correct blacklist flags, the target with the DVD device > is scanned with REPORTLUN which works correctly. > > Signed-off-by: Stephen Hemminger > Reviewed-by: K. Y. Srinivasan > Reviewed-by: Christoph Hellwig > Signed-off-by: Martin K. Petersen > --- > drivers/scsi/storvsc_drv.c | 27 +++++++++++++++++---------- > 1 file changed, 17 insertions(+), 10 deletions(-) I've queued this up, but it's interesting how you deleted the changelog comments here saying this was only needed for 4.11 and no older kernels :) thanks, greg k-h