From: Jiang Liu <jiang.liu@linux.intel.com>
Date: Wed, 26 Nov 2014 01:42:10 +0000 (+0800)
Subject: iommu/vt-d: Fix an off-by-one bug in __domain_mapping()
X-Git-Tag: v3.2.67~106
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c17a5f8956af869bd85195fc4f980a1acce03574;p=pandora-kernel.git

iommu/vt-d: Fix an off-by-one bug in __domain_mapping()

commit cc4f14aa170d895c9a43bdb56f62070c8a6da908 upstream.

There's an off-by-one bug in function __domain_mapping(), which may
trigger the BUG_ON(nr_pages < lvl_pages) when
	(nr_pages + 1) & superpage_mask == 0

The issue was introduced by commit 9051aa0268dc "intel-iommu: Combine
domain_pfn_mapping() and domain_sg_mapping()", which sets sg_res to
"nr_pages + 1" to avoid some of the 'sg_res==0' code paths.

It's safe to remove extra "+1" because sg_res is only used to calculate
page size now.

Reported-And-Tested-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-By: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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