[PATCH] scsi: hyper-v storsvc switch up to SPC-3

[Andy Whitcroft]

Suggested-By: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxxx>
---
 drivers/scsi/storvsc_drv.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 9969fa1..3903c8a 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1441,6 +1441,14 @@ static int storvsc_device_configure(struct scsi_device *sdevice)
 
 	sdevice->no_write_same = 1;
 
+	/*
+	 * hyper-v lies about its capabilities indicating it is only SPC-2
+	 * compliant, but actually implements the core SPC-3 features.
+	 * If we pretend to be SPC-3, we send RC16 which activates trim and
+	 * will query the appropriate VPD pages to enable trim.
+	 */
+	sdevice->scsi_level = SCSI_SPC_3;
+
 	return 0;
 }
 
-- 
1.7.9.5

(Downloaded from
http://kernel.ubuntu.com/git?p=jsalisbury/stable/trusty/ubuntu-trusty.git;a=patch;h=ff2c5fa3fa9adf0b919b9425e71a8ba044c31a7d
).

I think it's unwise to override the scsi_level at this particular point
because you are going to do it for ALL Hyper-V "disks" (perhaps all
Hyper-V SCSI devices?)...

Here's the SCSI inquiry information reported by a USB 2 hard disk being
passed passed-through by one of my 2012 R2 hosts:

# sg_inq /dev/sdc
standard INQUIRY:
  PQual=0  Device_type=0  RMB=0  version=0x02  [SCSI-2]
  [AERC=0]  [TrmTsk=0]  NormACA=0  HiSUP=0  Resp_data_format=1
  SCCS=0  ACC=0  TPGS=0  3PC=0  Protect=0  [BQue=0]
  EncServ=0  MultiP=0  [MChngr=0]  [ACKREQQ=0]  Addr16=0
  [RelAdr=0]  WBus16=0  Sync=0  Linked=0  [TranDis=0]  CmdQue=0
    length=36 (0x24)   Peripheral device type: disk
 Vendor identification: MDT MD50
 Product identification: 00AAKS-00TMA0   
 Product revision level: 

Is it OK to replace a scsi_level of SCSI-2 with SCSI_SPC_3? Additionally
is it also OK to force SCSI_SPC_3 on Hyper-V 2008?

> > > NryزXvØ?){nÇ?{zX}zj:v zZzf~zwÚ¢)jyA
> > >
> > > i
> N?????r??y????b?X??ǧv?^?)Þº{.n?+????{????zX????ܨ}???Æ z?&j:+v???????zZ+??+zf???h???~????i???z??w?????????&?)ߢf??^jÇ«y?m??@A?a???0??h???i

^^^ Where do these characters come from? I've occasionally seen them on
emails from other Microsoft folks posting to LKML too...

-- 
Sitsofe | http://sucs.org/~sits/
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