[ 3.5.y.z extended stable ] Patch "xen/blkback: Don't trust the handle from the frontend." has been added to staging queue

[Jan Beulich]

>>> On 04.03.13 at 21:48, Luis Henriques <luis.henriques at canonical.com> wrote:
> This is a note to let you know that I have just added a patch titled
> 
>     xen/blkback: Don't trust the handle from the frontend.
> 
> to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
> which can be found at:
> 
>  
> http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux- 
> 3.5.y-queue
> 
> If you, or anyone else, feels it should not be added to this tree, please 
> reply to this email.

Yesterday we settled on dropping this from stable branches.

Jan

> For more information about the 3.5.y.z tree, see
> https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable 
> 
> Thanks.
> -Luis
> 
> ------
> 
> From 386927b0c93e2f86e8a08076194483910626f121 Mon Sep 17 00:00:00 2001
> From: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
> Date: Wed, 16 Jan 2013 11:36:23 -0500
> Subject: [PATCH] xen/blkback: Don't trust the handle from the frontend.
> 
> commit 01c681d4c70d64cb72142a2823f27c4146a02e63 upstream.
> 
> The 'handle' is the device that the request is from. For the life-time
> of the ring we copy it from a request to a response so that the frontend
> is not surprised by it. But we do not need it - when we start processing
> I/Os we have our own 'struct phys_req' which has only most essential
> information about the request. In fact the 'vbd_translate' ends up
> over-writing the preq.dev with a value from the backend.
> 
> This assignment of preq.dev with the 'handle' value is superfluous
> so lets not do it.
> 
> Acked-by: Jan Beulich <jbeulich at suse.com>
> Acked-by: Ian Campbell <ian.campbell at citrix.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
> Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
> ---
>  drivers/block/xen-blkback/blkback.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/block/xen-blkback/blkback.c 
> b/drivers/block/xen-blkback/blkback.c
> index c6decb9..73d8c92 100644
> --- a/drivers/block/xen-blkback/blkback.c
> +++ b/drivers/block/xen-blkback/blkback.c
> @@ -623,7 +623,6 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
>  		goto fail_response;
>  	}
> 
> -	preq.dev           = req->u.rw.handle;
>  	preq.sector_number = req->u.rw.sector_number;
>  	preq.nr_sects      = 0;
> 
> --
> 1.8.1.2