Merge tag 'rxrpc-fixes-20190730' of git://git.kernel.org/pub/scm/linu…

…x/kernel/git/dhowells/linux-fs

David Howells says:

====================
Here are a couple of fixes for rxrpc:

 (1) Fix a potential deadlock in the peer keepalive dispatcher.

 (2) Fix a missing notification when a UDP sendmsg error occurs in rxrpc.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

net/rxrpc/ar-internal.h

@@ -1061,6 +1061,7 @@ void rxrpc_destroy_all_peers(struct rxrpc_net *);
 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *);
 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *);
 void rxrpc_put_peer(struct rxrpc_peer *);
+void rxrpc_put_peer_locked(struct rxrpc_peer *);
 
 /*
  * proc.c

net/rxrpc/peer_event.c

@@ -378,7 +378,7 @@ static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
 		spin_lock_bh(&rxnet->peer_hash_lock);
 		list_add_tail(&peer->keepalive_link,
 			      &rxnet->peer_keepalive[slot & mask]);
-		rxrpc_put_peer(peer);
+		rxrpc_put_peer_locked(peer);
 	}
 
 	spin_unlock_bh(&rxnet->peer_hash_lock);

net/rxrpc/peer_object.c

@@ -436,6 +436,24 @@ void rxrpc_put_peer(struct rxrpc_peer *peer)
 	}
 }
 
+/*
+ * Drop a ref on a peer record where the caller already holds the
+ * peer_hash_lock.
+ */
+void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
+{
+	const void *here = __builtin_return_address(0);
+	int n;
+
+	n = atomic_dec_return(&peer->usage);
+	trace_rxrpc_peer(peer, rxrpc_peer_put, n, here);
+	if (n == 0) {
+		hash_del_rcu(&peer->hash_link);
+		list_del_init(&peer->keepalive_link);
+		kfree_rcu(peer, rcu);
+	}
+}
+
 /*
  * Make sure all peer records have been discarded.
  */

net/rxrpc/sendmsg.c

@@ -226,6 +226,7 @@ static int rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
 			rxrpc_set_call_completion(call,
 						  RXRPC_CALL_LOCAL_ERROR,
 						  0, ret);
+			rxrpc_notify_socket(call);
 			goto out;
 		}
 		_debug("need instant resend %d", ret);