[3.16.y-ckt stable] Patch "ARM: 8404/1: dma-mapping: fix off-by-one error in bitmap size check" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    ARM: 8404/1: dma-mapping: fix off-by-one error in bitmap size check

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 26f98b66a55738783d7f543baa7ba502092d9ad8 Mon Sep 17 00:00:00 2001
From: Marek Szyprowski <m.szyprowski at samsung.com>
Date: Wed, 8 Jul 2015 13:21:55 +0100
Subject: ARM: 8404/1: dma-mapping: fix off-by-one error in bitmap size check

commit 462859aa7bbe1ac83ec4377a0a06fe60778f3f27 upstream.

nr_bitmaps member of mapping structure stores the number of already
allocated bitmaps and it is interpreted as loop iterator (it starts from
0 not from 1), so a comparison against number of possible bitmap
extensions should include this fact. This patch fixes this by changing
the extension failure condition. This issue has been introduced by
commit 4d852ef8c2544ce21ae41414099a7504c61164a0 ("arm: dma-mapping: Add
support to extend DMA IOMMU mappings").

Reported-by: Hyungwon Hwang <human.hwang at samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
Reviewed-by: Hyungwon Hwang <human.hwang at samsung.com>
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm/mm/dma-mapping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 1f88db06b133..0e09af35f69a 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -2013,7 +2013,7 @@ static int extend_iommu_mapping(struct dma_iommu_mapping *mapping)
 {
 	int next_bitmap;

-	if (mapping->nr_bitmaps > mapping->extensions)
+	if (mapping->nr_bitmaps >= mapping->extensions)
 		return -EINVAL;

 	next_bitmap = mapping->nr_bitmaps;