[trusty 1/1] UBUNTU: SAUCE: storvsc: force SPC-3 compliance on win8 and win8 r2 hosts

[Andy Whitcroft]

From: "K. Y. Srinivasan" <kys at microsoft.com>

On win8 and win8 r2 hosts force SPC-3 compliance for MSFT virtual disks.
Ubuntu has been carrying a similar patch outside the tree for a while now.
Starting with win10, the host will support SPC-3 compliance. Based on all
the testing that has been done on win8 and win8 r2 hosts, we are comfortable
claiming SPC-3 compliance on these hosts as well. This will enable TRIM
support on these hosts.

Suggested by: James Bottomley <James.Bottomley at HansenPartnership.com>
Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Reviewed-by: Long Li <longli at microsoft.com>
Signed-off-by: Christoph Hellwig <hch at lst.de>

[pending for v3.20 in the scsi-drivers tree]
BugLink: http://bugs.launchpad.net/bugs/1406867
Signed-off-by: Andy Whitcroft <apw at canonical.com>
---
 drivers/scsi/storvsc_drv.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index a11e5e9..1e1256c 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1459,6 +1459,19 @@ static int storvsc_device_configure(struct scsi_device *sdevice)
 	 */
 	sdevice->sdev_bflags |= msft_blist_flags;
 
+	/*
+	 * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
+	 * if the device is a MSFT virtual device.
+	 */
+	if (!strncmp(sdevice->vendor, "Msft", 4)) {
+		switch (vmbus_proto_version) {
+		case VERSION_WIN8:
+		case VERSION_WIN8_1:
+			sdevice->scsi_level = SCSI_SPC_3;
+			break;
+		}
+	}
+
 	return 0;
 }
 
-- 
2.1.4