[PATCH net-next 12/14] rxrpc: Provide more refcount helper functions [ver #2]

[David Howells]

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@xxxxxxxxxx>
---

 net/rxrpc/af_rxrpc.c     |    7 ++-----
 net/rxrpc/ar-internal.h  |   15 +++++++++++++--
 net/rxrpc/call_accept.c  |    2 +-
 net/rxrpc/call_object.c  |    2 +-
 net/rxrpc/conn_event.c   |    2 +-
 net/rxrpc/conn_object.c  |   12 ++++++------
 net/rxrpc/input.c        |    2 +-
 net/rxrpc/local_object.c |    2 +-
 8 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index b29bb50af5de..57dcbfc061e4 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 cfbd028aa551..c0ed5e7f22ef 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 5a70dc4e28c6..833ad0622b61 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 d83f2cbb80a9..45849a66bc56 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 a022439f6f5a..bf6971555eac 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 312b75091d29..1754f2e2e16b 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 cf540efa9c17..799aec18aa7b 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 009b321712bc..5703b0d18ed4 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;