ipv4: RCU changes in __mkroute_input()

Avoid two atomic ops on output device refcount

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

1 files changed, 3 insertions, 5 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 1cfe0d199e7c..7b8eacd5ac26 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1957,22 +1957,22 @@ static void ip_handle_martian_source(struct net_device *dev,
 #endif
 }
 
+/* called in rcu_read_lock() section */
 static int __mkroute_input(struct sk_buff *skb,
                            struct fib_result *res,
                            struct in_device *in_dev,
                            __be32 daddr, __be32 saddr, u32 tos,
                            struct rtable **result)
 {
-
         struct rtable *rth;
         int err;
         struct in_device *out_dev;
-        unsigned flags = 0;
+        unsigned int flags = 0;
         __be32 spec_dst;
         u32 itag;
 
         /* get a working reference to the output device */
-        out_dev = in_dev_get(FIB_RES_DEV(*res));
+        out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
         if (out_dev == NULL) {
                 if (net_ratelimit())
                         printk(KERN_CRIT "Bug in ip_route_input" \
@@ -2053,8 +2053,6 @@ static int __mkroute_input(struct sk_buff *skb,
         *result = rth;
         err = 0;
  cleanup:
-        /* release the working reference to the output device */
-        in_dev_put(out_dev);
         return err;
 }