inet: RCU changes in inetdev_by_index()

Convert inetdev_by_index() to not increment in_dev refcount.

Callers hold RCU or RTNL, and should not decrement in_dev refcount.

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

1 files changed, 4 insertions, 3 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index c2ff48fa18c7..dc94b0316b78 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -403,6 +403,9 @@ static int inet_set_ifa(struct net_device *dev, struct in_ifaddr *ifa)
         return inet_insert_ifa(ifa);
 }
 
+/* Caller must hold RCU or RTNL :
+ * We dont take a reference on found in_device
+ */
 struct in_device *inetdev_by_index(struct net *net, int ifindex)
 {
         struct net_device *dev;
@@ -411,7 +414,7 @@ struct in_device *inetdev_by_index(struct net *net, int ifindex)
         rcu_read_lock();
         dev = dev_get_by_index_rcu(net, ifindex);
         if (dev)
-                in_dev = in_dev_get(dev);
+                in_dev = rcu_dereference_rtnl(dev->ip_ptr);
         rcu_read_unlock();
         return in_dev;
 }
@@ -453,8 +456,6 @@ static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg
                 goto errout;
         }
 
-        __in_dev_put(in_dev);
-
         for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
              ifap = &ifa->ifa_next) {
                 if (tb[IFA_LOCAL] &&