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Commit ed7865a4 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9a57a9d2

net/ipv4/route.c

+3 −7
Original line number Diff line number Diff line
@@ -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 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, 
		       &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)