ipv4: avoid two atomic ops in ip_rt_redirect()

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

[ Fix build with CONFIG_IP_ROUTE_VERBOSE disabled. -DaveM ]

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

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 7b8eacd5ac26c70397af547120f7a5c47834d749..883b5c7195aca2470bf8826c3908bc5d7c3bf617 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1343,11 +1343,12 @@ static void rt_del(unsigned hash, struct rtable *rt)
        spin_unlock_bh(rt_hash_lock_addr(hash));
 }
 
+/* called in rcu_read_lock() section */
 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
                    __be32 saddr, struct net_device *dev)
 {
        int i, k;
-       struct in_device *in_dev = in_dev_get(dev);
+       struct in_device *in_dev = __in_dev_get_rcu(dev);
        struct rtable *rth, **rthp;
        __be32  skeys[2] = { saddr, 0 };
        int  ikeys[2] = { dev->ifindex, 0 };
@@ -1383,7 +1384,6 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
 
                        rthp=&rt_hash_table[hash].chain;
 
-                       rcu_read_lock();
                        while ((rth = rcu_dereference(*rthp)) != NULL) {
                                struct rtable *rt;
 
@@ -1405,12 +1405,10 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
                                        break;
 
                                dst_hold(&rth->u.dst);
-                               rcu_read_unlock();
 
                                rt = dst_alloc(&ipv4_dst_ops);
                                if (rt == NULL) {
                                        ip_rt_put(rth);
-                                       in_dev_put(in_dev);
                                        return;
                                }
 
@@ -1463,12 +1461,10 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
                                        ip_rt_put(rt);
                                goto do_next;
                        }
-                       rcu_read_unlock();
                do_next:
                        ;
                }
        }
-       in_dev_put(in_dev);
        return;
 
 reject_redirect:
@@ -1479,7 +1475,7 @@ reject_redirect:
                       &old_gw, dev->name, &new_gw,
                       &saddr, &daddr);
 #endif
-       in_dev_put(in_dev);
+       ;
 }
 
 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)