[ 016/187] bql: Fix POSDIFF() to integer overflow aware.

Greg Kroah-Hartman
2012-07-12T22:36:34Z

From: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>

[ Upstream commit 0cfd32b736ae0c36b42697584811042726c07cba ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
lib/dynamic_queue_limits.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- 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)