From fc7f0dd381720ea5ee5818645f7d0e9dece41cb0 Mon Sep 17 00:00:00 2001
From: Louis Langholtz <lou_langholtz@me.com>
Date: Thu, 15 Jan 2015 22:04:46 -0700
Subject: [PATCH] kernel: avoid overflow in cmp_range

Avoid overflow possibility.

[ The overflow is purely theoretical, since this is used for memory
  ranges that aren't even close to using the full 64 bits, but this is
  the right thing to do regardless.  - Linus ]

Signed-off-by: Louis Langholtz <lou_langholtz@me.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Peter Anvin <hpa@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/range.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/range.c b/kernel/range.c
index 322ea8e93e4b..82cfc285b046 100644
--- a/kernel/range.c
+++ b/kernel/range.c
@@ -113,12 +113,12 @@ static int cmp_range(const void *x1, const void *x2)
 {
 	const struct range *r1 = x1;
 	const struct range *r2 = x2;
-	s64 start1, start2;
 
-	start1 = r1->start;
-	start2 = r2->start;
-
-	return start1 - start2;
+	if (r1->start < r2->start)
+		return -1;
+	if (r1->start > r2->start)
+		return 1;
+	return 0;
 }
 
 int clean_sort_range(struct range *range, int az)
-- 
2.20.1