[IPV4]: Replace __in_dev_get with __in_dev_get_rcu/rtnl

The following patch renames __in_dev_get() to __in_dev_get_rtnl() and
introduces __in_dev_get_rcu() to cover the second case.

1) RCU with refcnt should use in_dev_get().
2) RCU without refcnt should use __in_dev_get_rcu().
3) All others must hold RTNL and use __in_dev_get_rtnl().

There is one exception in net/ipv4/route.c which is in fact a pre-existing
race condition.  I've marked it as such so that we remember to fix it.

This patch is based on suggestions and prior work by Suzanne Wood and
Paul McKenney.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index d41219e8037c..186f20c4a45e 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -1087,7 +1087,7 @@ fib_convert_rtentry(int cmd, struct nlmsghdr *nl, struct rtmsg *rtm,
                 rta->rta_oif = &dev->ifindex;
                 if (colon) {
                         struct in_ifaddr *ifa;
-                        struct in_device *in_dev = __in_dev_get(dev);
+                        struct in_device *in_dev = __in_dev_get_rtnl(dev);
                         if (!in_dev)
                                 return -ENODEV;
                         *colon = ':';
@@ -1268,7 +1268,7 @@ int fib_sync_up(struct net_device *dev)
                         }
                         if (nh->nh_dev == NULL || !(nh->nh_dev->flags&IFF_UP))
                                 continue;
-                        if (nh->nh_dev != dev || __in_dev_get(dev) == NULL)
+                        if (nh->nh_dev != dev || !__in_dev_get_rtnl(dev))
                                 continue;
                         alive++;
                         spin_lock_bh(&fib_multipath_lock);