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ipv4: avoid two atomic ops in ip_rt_redirect()
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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>
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Eric Dumazet authored and David S. Miller committed Jun 8, 2010
1 parent 9a57a9d commit ed7865a
Showing 1 changed file with 3 additions and 7 deletions.
10 changes: 3 additions & 7 deletions net/ipv4/route.c
Original file line number Diff line number Diff line change
Expand Up @@ -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 };
Expand Down Expand Up @@ -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;

Expand All @@ -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;
}

Expand Down Expand Up @@ -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:
Expand All @@ -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)
Expand Down

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