net: Remove spinlock from get_net_ns_by_id()

idr_find() is safe under rcu_read_lock() and
maybe_get_net() guarantees that net is alive.

Signed-off-by: Kirill Tkhai <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Kirill Tkhai

net/core/net_namespace.c

@@ -273,11 +273,9 @@ struct net *get_net_ns_by_id(struct net *net, int id)
 		return NULL;
 
 	rcu_read_lock();
-	spin_lock_bh(&net->nsid_lock);
 	peer = idr_find(&net->netns_ids, id);
 	if (peer)
 		peer = maybe_get_net(peer);
-	spin_unlock_bh(&net->nsid_lock);
 	rcu_read_unlock();
 
 	return peer;