mptfusion: enable no_write_same for vmware scsi disks

When using a virtual SCSI disk in a VMWare VM if blkdev_issue_zeroout is used
data can be improperly zeroed out using the mptfusion driver. This patch
disables write_same for this driver and the vmware subsystem_vendor which
ensures that manual zeroing out is used instead.

Cc: stable@vger.kernel.org
BugLink: http://bugs.launchpad.net/bugs/1371591
Reported-by: Bruce Lucas <bruce.lucas@mongodb.com>
Tested-by: Chris J Arges <chris.j.arges@canonical.com>
Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/message/fusion/mptspi.c

@@ -1419,6 +1419,11 @@ mptspi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto out_mptspi_probe;
         }
 
+	/* VMWare emulation doesn't properly implement WRITE_SAME
+	 */
+	if (pdev->subsystem_vendor == 0x15AD)
+		sh->no_write_same = 1;
+
 	spin_lock_irqsave(&ioc->FreeQlock, flags);
 
 	/* Attach the SCSI Host to the IOC structure