security: Remove rtnl_lock() in selinux_xfrm_notify_policyload()

rt_genid_bump_all() consists of ipv4 and ipv6 part.
ipv4 part is incrementing of net::ipv4::rt_genid,
and I see many places, where it's read without rtnl_lock().

ipv6 part calls __fib6_clean_all(), and it's also
called without rtnl_lock() in other places.

So, rtnl_lock() here was used to iterate net_namespace_list only,
and we can remove it.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

security/selinux/include/xfrm.h

@@ -47,12 +47,10 @@ static inline void selinux_xfrm_notify_policyload(void)
 {
 	struct net *net;
 
-	rtnl_lock();
 	down_read(&net_rwsem);
 	for_each_net(net)
 		rt_genid_bump_all(net);
 	up_read(&net_rwsem);
-	rtnl_unlock();
 }
 #else
 static inline int selinux_xfrm_enabled(void)