From 0cfd32b736ae0c36b42697584811042726c07cba Mon Sep 17 00:00:00 2001
From: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Date: Wed, 30 May 2012 12:24:39 +0000
Subject: [PATCH] bql: Fix POSDIFF() to integer overflow aware.

POSDIFF() fails to take into account integer overflow case.

Signed-off-by: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Denys Fedoryshchenko <denys@visp.net.lb>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 lib/dynamic_queue_limits.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/dynamic_queue_limits.c b/lib/dynamic_queue_limits.c
index 6ab4587d052b..c87eb76f2fd4 100644
--- a/lib/dynamic_queue_limits.c
+++ b/lib/dynamic_queue_limits.c
@@ -10,7 +10,7 @@
 #include <linux/jiffies.h>
 #include <linux/dynamic_queue_limits.h>
 
-#define POSDIFF(A, B) ((A) > (B) ? (A) - (B) : 0)
+#define POSDIFF(A, B) ((int)((A) - (B)) > 0 ? (A) - (B) : 0)
 
 /* Records completed count and recalculates the queue limit */
 void dql_completed(struct dql *dql, unsigned int count)
-- 
2.30.2