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

[Luis Henriques]

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.

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