[Acked] [Utopic][Trusty SRU][PATCH] mptfusion: enable no_write_same for vmware scsi disks

[Andy Whitcroft]

On Fri, Sep 26, 2014 at 09:37:27AM -0500, Chris J Arges wrote:
> BugLink: http://bugs.launchpad.net/bugs/1371591
> 
> 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 at vger.kernel.org
> 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>
> (cherry picked from http://git.infradead.org/users/hch/scsi-queue.git/
> commit/4089b71cc820a426d601283c92fcd4ffeb5139c2)
> Signed-off-by: Chris J Arges <chris.j.arges 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 49d1133..2fb90e2 100644
> --- a/drivers/message/fusion/mptspi.c
> +++ b/drivers/message/fusion/mptspi.c
> @@ -1420,6 +1420,11 @@ 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
> -- 

Looks to be what hch finally is applying.  Looks simple and safe, and
well contained.

Acked-by: Andy Whitcroft <apw at canonical.com>

-apw