From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH] storvsc: workaround for virtual DVD SCSI version Date: Wed, 8 Mar 2017 08:00:32 +0100 Message-ID: <7b3fcc1f-e446-032c-d02b-b9ab1ee6512e@suse.de> References: <20170307171553.13247-1-sthemmin@microsoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20170307171553.13247-1-sthemmin@microsoft.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: Stephen Hemminger , kys@microsoft.com, haiyangz@microsoft.com, longli@microsoft.com, martin.petersen@oracle.com, hch@lst.de Cc: devel@linuxdriverproject.org, Stephen Hemminger , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org List-Id: linux-scsi@vger.kernel.org On 03/07/2017 06:15 PM, Stephen Hemminger wrote: > 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 4.11 > 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 and that works correctly. > = > Patch needs to go in current 4.11, it is safe but not necessary > in older kernels. > = > Signed-off-by: Stephen Hemminger > --- > drivers/scsi/storvsc_drv.c | 27 +++++++++++++++++---------- > 1 file changed, 17 insertions(+), 10 deletions(-) > = > PS: The error handling does need to be fixed (have patches pending) > but that is interrelated with hotplug and can wait. > = Reviewed-by: Hannes Reinecke Cheers, Hannes -- = Dr. Hannes Reinecke Teamlead Storage & Networking hare@suse.de +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: F. Imend=F6rffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG N=FCrnberg)