rxrpc: Provide more refcount helper functions

Provide refcount helper functions for connections so that the code doesn't
touch local or connection usage counts directly.

Also make it such that local and peer put functions can take a NULL
pointer.

Signed-off-by: David Howells <dhowells@redhat.com>

8 files changed, 26 insertions, 18 deletions

diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index b29bb50..57dcbfc 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -674,11 +674,8 @@ static int rxrpc_release_sock(struct sock *sk)
 	flush_workqueue(rxrpc_workqueue);
 	rxrpc_purge_queue(&sk->sk_receive_queue);
 
-	if (rx->local) {
-		rxrpc_put_local(rx->local);
-		rx->local = NULL;
-	}
-
+	rxrpc_put_local(rx->local);
+	rx->local = NULL;
 	key_put(rx->key);
 	rx->key = NULL;
 	key_put(rx->securities);
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index cfbd028..c0ed5e7 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -597,6 +597,17 @@ static inline bool rxrpc_conn_is_service(const struct rxrpc_connection *conn)
 	return conn->proto.in_clientflag;
 }
 
+static inline void rxrpc_get_connection(struct rxrpc_connection *conn)
+{
+	atomic_inc(&conn->usage);
+}
+
+static inline
+struct rxrpc_connection *rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
+{
+	return atomic_inc_not_zero(&conn->usage) ? conn : NULL;
+}
+
 /*
  * input.c
  */
@@ -645,7 +656,7 @@ struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local)
 
 static inline void rxrpc_put_local(struct rxrpc_local *local)
 {
-	if (atomic_dec_and_test(&local->usage))
+	if (local && atomic_dec_and_test(&local->usage))
 		__rxrpc_put_local(local);
 }
 
@@ -702,7 +713,7 @@ struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
 extern void __rxrpc_put_peer(struct rxrpc_peer *peer);
 static inline void rxrpc_put_peer(struct rxrpc_peer *peer)
 {
-	if (atomic_dec_and_test(&peer->usage))
+	if (peer && atomic_dec_and_test(&peer->usage))
 		__rxrpc_put_peer(peer);
 }
 
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index 5a70dc4..833ad06 100644
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -141,7 +141,7 @@ static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
 			_debug("await conn sec");
 			list_add_tail(&call->accept_link, &rx->secureq);
 			call->conn->state = RXRPC_CONN_SERVER_CHALLENGING;
-			atomic_inc(&call->conn->usage);
+			rxrpc_get_connection(call->conn);
 			set_bit(RXRPC_CONN_CHALLENGE, &call->conn->events);
 			rxrpc_queue_conn(call->conn);
 		} else {
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index d83f2cb..45849a6 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -515,7 +515,7 @@ struct rxrpc_call *rxrpc_incoming_call(struct rxrpc_sock *rx,
 	rb_insert_color(&call->conn_node, &conn->calls);
 	conn->channels[call->channel] = call;
 	sock_hold(&rx->sk);
-	atomic_inc(&conn->usage);
+	rxrpc_get_connection(conn);
 	write_unlock_bh(&conn->lock);
 
 	spin_lock(&conn->params.peer->lock);
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index a022439..bf69715 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -263,7 +263,7 @@ void rxrpc_process_connection(struct work_struct *work)
 
 	_enter("{%d}", conn->debug_id);
 
-	atomic_inc(&conn->usage);
+	rxrpc_get_connection(conn);
 
 	if (test_and_clear_bit(RXRPC_CONN_CHALLENGE, &conn->events)) {
 		rxrpc_secure_connection(conn);
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 312b750..1754f2e 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -333,7 +333,7 @@ static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
 	 * channel.
 	 */
 	chan = 0;
-	atomic_inc(&conn->usage);
+	rxrpc_get_connection(conn);
 	conn->avail_calls = RXRPC_MAXCALLS - 1;
 	conn->channels[chan] = call;
 	conn->call_counter = 1;
@@ -392,7 +392,7 @@ int rxrpc_connect_call(struct rxrpc_sock *rx,
 			       conn->channels[1] == NULL ||
 			       conn->channels[2] == NULL ||
 			       conn->channels[3] == NULL);
-			atomic_inc(&conn->usage);
+			rxrpc_get_connection(conn);
 			break;
 		}
 
@@ -412,7 +412,7 @@ int rxrpc_connect_call(struct rxrpc_sock *rx,
 			       conn->channels[1] == NULL &&
 			       conn->channels[2] == NULL &&
 			       conn->channels[3] == NULL);
-			atomic_inc(&conn->usage);
+			rxrpc_get_connection(conn);
 			list_move(&conn->bundle_link, &bundle->avail_conns);
 			break;
 		}
@@ -629,7 +629,7 @@ found_extant_connection:
 		read_unlock_bh(&trans->conn_lock);
 		goto security_mismatch;
 	}
-	atomic_inc(&conn->usage);
+	rxrpc_get_connection(conn);
 	read_unlock_bh(&trans->conn_lock);
 	goto success;
 
@@ -639,7 +639,7 @@ found_extant_second:
 		write_unlock_bh(&trans->conn_lock);
 		goto security_mismatch;
 	}
-	atomic_inc(&conn->usage);
+	rxrpc_get_connection(conn);
 	write_unlock_bh(&trans->conn_lock);
 	kfree(candidate);
 	goto success;
@@ -698,7 +698,7 @@ struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_transport *trans,
 	return NULL;
 
 found:
-	atomic_inc(&conn->usage);
+	rxrpc_get_connection(conn);
 	read_unlock_bh(&trans->conn_lock);
 	_leave(" = %p", conn);
 	return conn;
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index cf540ef..799aec1 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -580,7 +580,7 @@ static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 {
 	_enter("%p,%p", conn, skb);
 
-	atomic_inc(&conn->usage);
+	rxrpc_get_connection(conn);
 	skb_queue_tail(&conn->rx_queue, skb);
 	rxrpc_queue_conn(conn);
 }
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index 009b321..5703b0d 100644
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -209,7 +209,7 @@ struct rxrpc_local *rxrpc_lookup_local(const struct sockaddr_rxrpc *srx)
 		 * bind the transport socket may still fail if we're attempting
 		 * to use a local address that the dying object is still using.
 		 */
-		if (!atomic_inc_not_zero(&local->usage)) {
+		if (!rxrpc_get_local_maybe(local)) {
 			cursor = cursor->next;
 			list_del_init(&local->link);
 			break;