From ce3c869283739379134e1a90c37dd1a30b5f31b7 Mon Sep 17 00:00:00 2001
From: Nicolas Kaiser <nikai@nikai.net>
Date: Fri, 4 Mar 2011 13:49:41 +0000
Subject: [PATCH] drivers/net/macvtap: fix error check

'len' is unsigned of type size_t and can't be negative.

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/macvtap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 5933621ac3ff..fc27a9926d9e 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -528,8 +528,9 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q,
 		vnet_hdr_len = q->vnet_hdr_sz;
 
 		err = -EINVAL;
-		if ((len -= vnet_hdr_len) < 0)
+		if (len < vnet_hdr_len)
 			goto err;
+		len -= vnet_hdr_len;
 
 		err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,
 					   sizeof(vnet_hdr));