From ed7865a47d4759e85bbd7bed44bee411d868eaad Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 7 Jun 2010 21:49:44 -0700 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/ipv4/route.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 7b8eacd..883b5c7 100644 --- 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) -- 2.7.4