ipv4: Use per-netns RTNL helpers in inet_rtm_newaddr().

inet_rtm_to_ifa() and find_matching_ifa() are called
under rtnl_net_lock().

__in_dev_get_rtnl() and in_dev_for_each_ifa_rtnl() there
can use per-netns RTNL helpers.

Let's define and use __in_dev_get_rtnl_net() and
in_dev_for_each_ifa_rtnl_net().

Signed-off-by: Kuniyuki Iwashima <[e-mail]>
Reviewed-by: Eric Dumazet <[e-mail]>
Signed-off-by: Paolo Abeni <[e-mail]>

include/linux/inetdevice.h

···
 	for (ifa = rtnl_dereference((in_dev)->ifa_list); ifa;	\
 	     ifa = rtnl_dereference(ifa->ifa_next))
 
+#define in_dev_for_each_ifa_rtnl_net(net, ifa, in_dev)			\
+	for (ifa = rtnl_net_dereference(net, (in_dev)->ifa_list); ifa;	\
+	     ifa = rtnl_net_dereference(net, ifa->ifa_next))
+
 #define in_dev_for_each_ifa_rcu(ifa, in_dev)			\
 	for (ifa = rcu_dereference((in_dev)->ifa_list); ifa;	\
 	     ifa = rcu_dereference(ifa->ifa_next))
···
 static inline struct in_device *__in_dev_get_rtnl(const struct net_device *dev)
 {
 	return rtnl_dereference(dev->ip_ptr);
+}
+
+static inline struct in_device *__in_dev_get_rtnl_net(const struct net_device *dev)
+{
+	return rtnl_net_dereference(dev_net(dev), dev->ip_ptr);
 }
 
 /* called with rcu_read_lock or rtnl held */

net/ipv4/devinet.c

···
 		goto errout;
 	}
 
-	in_dev = __in_dev_get_rtnl(dev);
+	in_dev = __in_dev_get_rtnl_net(dev);
 	err = -ENOBUFS;
 	if (!in_dev)
 		goto errout;
···
 	return ERR_PTR(err);
 }
 
-static struct in_ifaddr *find_matching_ifa(struct in_ifaddr *ifa)
+static struct in_ifaddr *find_matching_ifa(struct net *net, struct in_ifaddr *ifa)
 {
 	struct in_device *in_dev = ifa->ifa_dev;
 	struct in_ifaddr *ifa1;
 
-	in_dev_for_each_ifa_rtnl(ifa1, in_dev) {
+	in_dev_for_each_ifa_rtnl_net(net, ifa1, in_dev) {
 		if (ifa1->ifa_mask == ifa->ifa_mask &&
 		    inet_ifa_match(ifa1->ifa_address, ifa) &&
 		    ifa1->ifa_local == ifa->ifa_local)
···
 		goto unlock;
 	}
 
-	ifa_existing = find_matching_ifa(ifa);
+	ifa_existing = find_matching_ifa(net, ifa);
 	if (!ifa_existing) {
 		/* It would be best to check for !NLM_F_CREATE here but
 		 * userspace already relies on not having to provide this.