tipc: eliminate upcall function pointers between port and socket

Due to the original one-to-many relation between port and user API
layers, upcalls to the API have been performed via function pointers,
installed in struct tipc_port at creation. Since this relation now
always is one-to-one, we can instead use ordinary function calls.

We remove the function pointers 'dispatcher' and ´wakeup' from
struct tipc_port, and replace them with calls to the renamed
functions tipc_sk_rcv() and tipc_sk_wakeup().

At the same time we change the name and signature of the functions
tipc_createport() and tipc_deleteport() to reflect their new role
as mere initialization/destruction functions.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/link.c

@@ -327,8 +327,6 @@ static int link_schedule_port(struct tipc_link *l_ptr, u32 origport, u32 sz)
 	spin_lock_bh(&tipc_port_list_lock);
 	p_ptr = tipc_port_lock(origport);
 	if (p_ptr) {
-		if (!p_ptr->wakeup)
-			goto exit;
 		if (!list_empty(&p_ptr->wait_list))
 			goto exit;
 		p_ptr->congested = 1;
@@ -363,7 +361,7 @@ void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all)
 		list_del_init(&p_ptr->wait_list);
 		spin_lock_bh(p_ptr->lock);
 		p_ptr->congested = 0;
-		p_ptr->wakeup(p_ptr);
+		tipc_port_wakeup(p_ptr);
 		win -= p_ptr->waiting_pkts;
 		spin_unlock_bh(p_ptr->lock);
 	}

net/tipc/port.c

@@ -190,33 +190,32 @@ void tipc_port_mcast_rcv(struct sk_buff *buf, struct tipc_port_list *dp)
 	tipc_port_list_free(dp);
 }
 
-/**
- * tipc_createport - create a generic TIPC port
+
+void tipc_port_wakeup(struct tipc_port *port)
+{
+	tipc_sk_wakeup(tipc_port_to_sk(port));
+}
+
+/* tipc_port_init - intiate TIPC port and lock it
  *
- * Returns pointer to (locked) TIPC port, or NULL if unable to create it
+ * Returns obtained reference if initialization is successful, zero otherwise
  */
-struct tipc_port *tipc_createport(struct sock *sk,
-				  u32 (*dispatcher)(struct tipc_port *,
-				  struct sk_buff *),
-				  void (*wakeup)(struct tipc_port *),
-				  const u32 importance)
+u32 tipc_port_init(struct tipc_port *p_ptr,
+		   const unsigned int importance)
 {
-	struct tipc_port *p_ptr = tipc_sk_port(sk);
 	struct tipc_msg *msg;
 	u32 ref;
 
 	ref = tipc_ref_acquire(p_ptr, &p_ptr->lock);
 	if (!ref) {
 		pr_warn("Port registration failed, ref. table exhausted\n");
-		return NULL;
+		return 0;
 	}
 
 	p_ptr->max_pkt = MAX_PKT_DEFAULT;
 	p_ptr->ref = ref;
 	INIT_LIST_HEAD(&p_ptr->wait_list);
 	INIT_LIST_HEAD(&p_ptr->subscription.nodesub_list);
-	p_ptr->dispatcher = dispatcher;
-	p_ptr->wakeup = wakeup;
 	k_init_timer(&p_ptr->timer, (Handler)port_timeout, ref);
 	INIT_LIST_HEAD(&p_ptr->publications);
 	INIT_LIST_HEAD(&p_ptr->port_list);
@@ -232,10 +231,10 @@ struct tipc_port *tipc_createport(struct sock *sk,
 	msg_set_origport(msg, ref);
 	list_add_tail(&p_ptr->port_list, &ports);
 	spin_unlock_bh(&tipc_port_list_lock);
-	return p_ptr;
+	return ref;
 }
 
-int tipc_deleteport(struct tipc_port *p_ptr)
+void tipc_port_destroy(struct tipc_port *p_ptr)
 {
 	struct sk_buff *buf = NULL;
 
@@ -257,7 +256,6 @@ int tipc_deleteport(struct tipc_port *p_ptr)
 	spin_unlock_bh(&tipc_port_list_lock);
 	k_term_timer(&p_ptr->timer);
 	tipc_net_route_msg(buf);
-	return 0;
 }
 
 static int port_unreliable(struct tipc_port *p_ptr)
@@ -530,13 +528,12 @@ void tipc_port_proto_rcv(struct sk_buff *buf)
 	/* Process protocol message sent by peer */
 	switch (msg_type(msg)) {
 	case CONN_ACK:
-		wakeable = tipc_port_congested(p_ptr) && p_ptr->congested &&
-			p_ptr->wakeup;
+		wakeable = tipc_port_congested(p_ptr) && p_ptr->congested;
 		p_ptr->acked += msg_msgcnt(msg);
 		if (!tipc_port_congested(p_ptr)) {
 			p_ptr->congested = 0;
 			if (wakeable)
-				p_ptr->wakeup(p_ptr);
+				tipc_port_wakeup(p_ptr);
 		}
 		break;
 	case CONN_PROBE:
@@ -865,7 +862,7 @@ int tipc_port_rcv(struct sk_buff *buf)
 	/* validate destination & pass to port, otherwise reject message */
 	p_ptr = tipc_port_lock(destport);
 	if (likely(p_ptr)) {
-		err = p_ptr->dispatcher(p_ptr, buf);
+		err = tipc_sk_rcv(tipc_port_to_sk(p_ptr), buf);
 		tipc_port_unlock(p_ptr);
 		if (likely(!err))
 			return dsz;

net/tipc/port.h

@@ -59,8 +59,6 @@
  * @ref: unique reference to port in TIPC object registry
  * @phdr: preformatted message header used when sending messages
  * @port_list: adjacent ports in TIPC's global list of ports
- * @dispatcher: ptr to routine which handles received messages
- * @wakeup: ptr to routine to call when port is no longer congested
  * @wait_list: adjacent ports in list of ports waiting on link congestion
  * @waiting_pkts:
  * @sent: # of non-empty messages sent by port
@@ -84,8 +82,6 @@ struct tipc_port {
 	u32 ref;
 	struct tipc_msg phdr;
 	struct list_head port_list;
-	u32 (*dispatcher)(struct tipc_port *, struct sk_buff *);
-	void (*wakeup)(struct tipc_port *);
 	struct list_head wait_list;
 	u32 waiting_pkts;
 	u32 sent;
@@ -104,17 +100,14 @@ struct tipc_port_list;
 /*
  * TIPC port manipulation routines
  */
-struct tipc_port *tipc_createport(struct sock *sk,
-				  u32 (*dispatcher)(struct tipc_port *,
-				  struct sk_buff *),
-				  void (*wakeup)(struct tipc_port *),
-				  const u32 importance);
+u32 tipc_port_init(struct tipc_port *p_ptr,
+		   const unsigned int importance);
 
 int tipc_reject_msg(struct sk_buff *buf, u32 err);
 
 void tipc_acknowledge(u32 port_ref, u32 ack);
 
-int tipc_deleteport(struct tipc_port *p_ptr);
+void tipc_port_destroy(struct tipc_port *p_ptr);
 
 int tipc_portimportance(u32 portref, unsigned int *importance);
 int tipc_set_portimportance(u32 portref, unsigned int importance);
@@ -136,6 +129,7 @@ int tipc_port_disconnect(u32 portref);
 
 int tipc_port_shutdown(u32 ref);
 
+void tipc_port_wakeup(struct tipc_port *port);
 
 /*
  * The following routines require that the port be locked on entry

net/tipc/socket.c

@@ -44,10 +44,7 @@
 
 #define CONN_TIMEOUT_DEFAULT	8000	/* default connect timeout = 8s */
 
-
 static int backlog_rcv(struct sock *sk, struct sk_buff *skb);
-static u32 dispatch(struct tipc_port *tport, struct sk_buff *buf);
-static void wakeupdispatch(struct tipc_port *tport);
 static void tipc_data_ready(struct sock *sk, int len);
 static void tipc_write_space(struct sock *sk);
 static int tipc_release(struct socket *sock);
@@ -181,10 +178,8 @@ static int tipc_sk_create(struct net *net, struct socket *sock, int protocol,
 	if (sk == NULL)
 		return -ENOMEM;
 
-	/* Allocate TIPC port for socket to use */
-	tp_ptr = tipc_createport(sk, &dispatch, &wakeupdispatch,
-				 TIPC_LOW_IMPORTANCE);
-	if (unlikely(!tp_ptr)) {
+	tp_ptr = tipc_sk_port(sk);
+	if (!tipc_port_init(tp_ptr, TIPC_LOW_IMPORTANCE)) {
 		sk_free(sk);
 		return -ENOMEM;
 	}
@@ -199,7 +194,6 @@ static int tipc_sk_create(struct net *net, struct socket *sock, int protocol,
 	sk->sk_data_ready = tipc_data_ready;
 	sk->sk_write_space = tipc_write_space;
 	tipc_sk(sk)->conn_timeout = CONN_TIMEOUT_DEFAULT;
-
 	spin_unlock_bh(tp_ptr->lock);
 
 	if (sock->state == SS_READY) {
@@ -207,7 +201,6 @@ static int tipc_sk_create(struct net *net, struct socket *sock, int protocol,
 		if (sock->type == SOCK_DGRAM)
 			tipc_set_portunreliable(tp_ptr->ref, 1);
 	}
-
 	return 0;
 }
 
@@ -337,7 +330,7 @@ static int tipc_release(struct socket *sock)
 	 * Delete TIPC port; this ensures no more messages are queued
 	 * (also disconnects an active connection & sends a 'FIN-' to peer)
 	 */
-	res = tipc_deleteport(tport);
+	tipc_port_destroy(tport);
 
 	/* Discard any remaining (connection-based) messages in receive queue */
 	__skb_queue_purge(&sk->sk_receive_queue);
@@ -1430,17 +1423,16 @@ static int backlog_rcv(struct sock *sk, struct sk_buff *buf)
 }
 
 /**
- * dispatch - handle incoming message
- * @tport: TIPC port that received message
+ * tipc_sk_rcv - handle incoming message
+ * @sk:  socket receiving message
  * @buf: message
  *
  * Called with port lock already taken.
  *
  * Returns TIPC error status code (TIPC_OK if message is not to be rejected)
  */
-static u32 dispatch(struct tipc_port *port, struct sk_buff *buf)
+u32 tipc_sk_rcv(struct sock *sk, struct sk_buff *buf)
 {
-	struct sock *sk = tipc_port_to_sk(port);
 	u32 res;
 
 	/*
@@ -1463,18 +1455,6 @@ static u32 dispatch(struct tipc_port *port, struct sk_buff *buf)
 	return res;
 }
 
-/**
- * wakeupdispatch - wake up port after congestion
- * @tport: port to wakeup
- *
- * Called with port lock already taken.
- */
-static void wakeupdispatch(struct tipc_port *port)
-{
-	struct sock *sk = tipc_port_to_sk(port);
-	sk->sk_write_space(sk);
-}
-
 static int tipc_wait_for_connect(struct socket *sock, long *timeo_p)
 {
 	struct sock *sk = sock->sk;

net/tipc/socket.h

@@ -67,4 +67,11 @@ static inline struct sock *tipc_port_to_sk(const struct tipc_port *port)
 	return &(container_of(port, struct tipc_sock, port))->sk;
 }
 
+static inline void tipc_sk_wakeup(struct sock *sk)
+{
+	sk->sk_write_space(sk);
+}
+
+u32 tipc_sk_rcv(struct sock *sk, struct sk_buff *buf);
+
 #endif