Patchwork [net-next-2.6] net: avoid two atomic ops in ip_rcv_options()

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Submitter Eric Dumazet
Date June 7, 2010, 1:54 p.m.
Message ID <1275918886.2545.87.camel@edumazet-laptop>
Download mbox | patch
Permalink /patch/54855/
State Accepted
Delegated to: David Miller
Headers show

Comments

Eric Dumazet - June 7, 2010, 1:54 p.m.
in_dev_get() -> __in_dev_get_rcu() in a rcu protected function.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
 net/ipv4/ip_input.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)



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David Miller - June 8, 2010, 4:26 a.m.
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Mon, 07 Jun 2010 15:54:46 +0200

> in_dev_get() -> __in_dev_get_rcu() in a rcu protected function.
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Applied.
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Patch

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index d52c9da..27b5a09 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -298,18 +298,16 @@  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))