ipv4, ipv6: kill ip_mc_{join, leave}_group and ipv6_sock_mc_{join, drop}

in favor of their inner __ ones, which doesn't grab rtnl.

As these functions need to operate on a locked socket, we can't be
grabbing rtnl by then. It's too late and doing so causes reversed
locking.

So this patch:
- move rtnl handling to callers instead while already fixing some
  reversed locking situations, like on vxlan and ipvs code.
- renames __ ones to not have the __ mark:
  __ip_mc_{join,leave}_group -> ip_mc_{join,leave}_group
  __ipv6_sock_mc_{join,drop} -> ipv6_sock_mc_{join,drop}

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -1097,7 +1097,6 @@ EXPORT_SYMBOL_GPL(vxlan_sock_release);
 
 /* Callback to update multicast group membership when first VNI on
  * multicast asddress is brought up
- * Done as workqueue because ip_mc_join_group acquires RTNL.
  */
 static void vxlan_igmp_join(struct work_struct *work)
 {
@@ -1107,6 +1106,7 @@ static void vxlan_igmp_join(struct work_struct *work)
 	union vxlan_addr *ip = &vxlan->default_dst.remote_ip;
 	int ifindex = vxlan->default_dst.remote_ifindex;
 
+	rtnl_lock();
 	lock_sock(sk);
 	if (ip->sa.sa_family == AF_INET) {
 		struct ip_mreqn mreq = {
@@ -1122,6 +1122,7 @@ static void vxlan_igmp_join(struct work_struct *work)
 #endif
 	}
 	release_sock(sk);
+	rtnl_unlock();
 
 	vxlan_sock_release(vs);
 	dev_put(vxlan->dev);
@@ -1136,6 +1137,7 @@ static void vxlan_igmp_leave(struct work_struct *work)
 	union vxlan_addr *ip = &vxlan->default_dst.remote_ip;
 	int ifindex = vxlan->default_dst.remote_ifindex;
 
+	rtnl_lock();
 	lock_sock(sk);
 	if (ip->sa.sa_family == AF_INET) {
 		struct ip_mreqn mreq = {
@@ -1152,6 +1154,7 @@ static void vxlan_igmp_leave(struct work_struct *work)
 	}
 
 	release_sock(sk);
+	rtnl_unlock();
 
 	vxlan_sock_release(vs);
 	dev_put(vxlan->dev);