[PATCH 3.13 048/105] mptfusion: enable no_write_same for vmware scsi disks

Kamal Mostafa kamal at canonical.com
Mon Oct 27 18:56:23 UTC 2014 -stable review patch.  If anyone has any objections, please let me know.


From: Chris J Arges <chris.j.arges at canonical.com>

commit 4089b71cc820a426d601283c92fcd4ffeb5139c2 upstream.

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.

BugLink: http://bugs.launchpad.net/bugs/1371591
Reported-by: Bruce Lucas <bruce.lucas at mongodb.com>
Tested-by: Chris J Arges <chris.j.arges at canonical.com>
Signed-off-by: Chris J Arges <chris.j.arges at canonical.com>
Reviewed-by: Martin K. Petersen <martin.petersen at oracle.com>
Signed-off-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
 drivers/message/fusion/mptspi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/message/fusion/mptspi.c b/drivers/message/fusion/mptspi.c
index 5653e50..424f51d 100644
--- a/drivers/message/fusion/mptspi.c
+++ b/drivers/message/fusion/mptspi.c
@@ -1422,6 +1422,11 @@ 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

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