tipc: enqueue arrived buffers in socket in separate function

The code for enqueuing arriving buffers in the function tipc_sk_rcv()
contains long code lines and currently goes to two indentation levels.
As a cosmetic preparaton for the next commits, we break it out into
a separate function.
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/socket.c

@@ -1764,6 +1764,35 @@ static int tipc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 	return 0;
 }
 
+/**
+ * tipc_sk_enqueue_skb - enqueue buffer to socket or backlog queue
+ * @sk: socket
+ * @skb: pointer to message. Set to NULL if buffer is consumed.
+ * @dnode: if buffer should be forwarded/returned, send to this node
+ *
+ * Caller must hold socket lock
+ *
+ * Returns TIPC_OK (0) or -tipc error code
+ */
+static int tipc_sk_enqueue_skb(struct sock *sk, struct sk_buff **skb)
+{
+	unsigned int lim;
+	atomic_t *dcnt;
+
+	if (unlikely(!*skb))
+		return TIPC_OK;
+	if (!sock_owned_by_user(sk))
+		return filter_rcv(sk, skb);
+	dcnt = &tipc_sk(sk)->dupl_rcvcnt;
+	if (sk->sk_backlog.len)
+		atomic_set(dcnt, 0);
+	lim = rcvbuf_limit(sk, *skb) + atomic_read(dcnt);
+	if (unlikely(sk_add_backlog(sk, *skb, lim)))
+		return -TIPC_ERR_OVERLOAD;
+	*skb = NULL;
+	return TIPC_OK;
+}
+
 /**
  * tipc_sk_rcv - handle incoming message
  * @skb: buffer containing arriving message
@@ -1776,8 +1805,7 @@ int tipc_sk_rcv(struct net *net, struct sk_buff *skb)
 	struct tipc_net *tn;
 	struct sock *sk;
 	u32 dport = msg_destport(buf_msg(skb));
-	int err = TIPC_OK;
-	uint limit;
+	int err;
 	u32 dnode;
 
 	/* Validate destination and message */
@@ -1788,20 +1816,8 @@ int tipc_sk_rcv(struct net *net, struct sk_buff *skb)
 	}
 	sk = &tsk->sk;
 
-	/* Queue message */
 	spin_lock_bh(&sk->sk_lock.slock);
-
-	if (!sock_owned_by_user(sk)) {
-		err = filter_rcv(sk, &skb);
-	} else {
-		if (sk->sk_backlog.len == 0)
-			atomic_set(&tsk->dupl_rcvcnt, 0);
-		limit = rcvbuf_limit(sk, skb) + atomic_read(&tsk->dupl_rcvcnt);
-		if (likely(!sk_add_backlog(sk, skb, limit)))
-			skb = NULL;
-		else
-			err = -TIPC_ERR_OVERLOAD;
-	}
+	err = tipc_sk_enqueue_skb(sk, &skb);
 	spin_unlock_bh(&sk->sk_lock.slock);
 	sock_put(sk);
 exit: