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>

1 files changed, 2 insertions, 4 deletions

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index d274078b1665..08a3b121f908 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))