From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Mon, 7 Jun 2010 03:54:46 +0000 (+0000)
Subject: net: avoid two atomic ops in ip_rcv_options()
X-Git-Tag: v2.6.36-rc1~571^2~623
X-Git-Url: https://bbs.cooldavid.org/git/?a=commitdiff_plain;h=6e8b11b43b0c2e901734e2cdd70c6e325a90c4ef;p=net-next-2.6.git

net: avoid two atomic ops in ip_rcv_options()

in_dev_get() -> __in_dev_get_rcu() in a rcu protected function.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index d274078b166..08a3b121f90 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -293,18 +293,16 @@ static inline int ip_rcv_options(struct sk_buff *skb)
 	}
 
 	if (unlikely(opt->srr)) {
-		struct in_device *in_dev = in_dev_get(dev);
+		struct in_device *in_dev = __in_dev_get_rcu(dev);
+
 		if (in_dev) {
 			if (!IN_DEV_SOURCE_ROUTE(in_dev)) {
 				if (IN_DEV_LOG_MARTIANS(in_dev) &&
 				    net_ratelimit())
 					printk(KERN_INFO "source route option %pI4 -> %pI4\n",
 					       &iph->saddr, &iph->daddr);
-				in_dev_put(in_dev);
 				goto drop;
 			}
-
-			in_dev_put(in_dev);
 		}
 
 		if (ip_options_rcv_srr(skb))