[NET] generalise wait_for_tcp_connect

This will be used by the poor cousins, look, for instance, at
x25_wait_for_connection_establishment :-)
Signed-off-by: Arnaldo Carvalho de Melo <acme@conectiva.com.br>

include/linux/tcp.h

@@ -371,8 +371,6 @@ struct tcp_opt {
 	struct open_request	*accept_queue;
 	struct open_request	*accept_queue_tail;
 
-	int			write_pending;	/* A write to socket waits to start. */
-
 	unsigned int		keepalive_time;	  /* time before keep alive takes place */
 	unsigned int		keepalive_intvl;  /* time interval between keep alive probes */
 	int			linger2;

include/net/sock.h

@@ -167,6 +167,7 @@ struct sock_common {
   *	@sk_socket - Identd and reporting IO signals
   *	@sk_user_data - RPC layer private data
   *	@sk_owner - module that owns this socket
+  *	@sk_write_pending - a write to stream socket waits to start
   *	@sk_state_change - callback to indicate change in the state of the sock
   *	@sk_data_ready - callback to indicate there is data to be processed
   *	@sk_write_space - callback to indicate there is bf sending space available
@@ -247,6 +248,7 @@ struct sock {
 	struct socket		*sk_socket;
 	void			*sk_user_data;
 	struct module		*sk_owner;
+	int			sk_write_pending;
 	void			*sk_security;
 	void			(*sk_state_change)(struct sock *sk);
 	void			(*sk_data_ready)(struct sock *sk, int bytes);
@@ -458,6 +460,8 @@ do {	if (!(__sk)->sk_backlog.tail) {				\
 	rc;							\
 })
 
+extern int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
+
 extern int sk_wait_data(struct sock *sk, long *timeo);
 
 /* IP protocol blocks we attach to sockets.

net/core/sock.c

@@ -1176,6 +1176,7 @@ void sock_init_data(struct socket *sock, struct sock *sk)
 	sk->sk_peercred.pid 	=	0;
 	sk->sk_peercred.uid	=	-1;
 	sk->sk_peercred.gid	=	-1;
+	sk->sk_write_pending	=	0;
 	sk->sk_rcvlowat		=	1;
 	sk->sk_rcvtimeo		=	MAX_SCHEDULE_TIMEOUT;
 	sk->sk_sndtimeo		=	MAX_SCHEDULE_TIMEOUT;

net/core/stream.c

@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/net.h>
 #include <linux/signal.h>
+#include <linux/tcp.h>
 #include <linux/wait.h>
 #include <net/sock.h>
 
@@ -39,3 +40,39 @@ void sk_stream_write_space(struct sock *sk)
 }
 
 EXPORT_SYMBOL(sk_stream_write_space);
+
+/**
+ * sk_stream_wait_connect - Wait for a socket to get into the connected state
+ * @sk - sock to wait on
+ * @timeo_p - for how long to wait
+ *
+ * Must be called with the socket locked.
+ */
+int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
+{
+	struct task_struct *tsk = current;
+	DEFINE_WAIT(wait);
+
+	while (1) {
+		if (sk->sk_err)
+			return sock_error(sk);
+		if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))
+			return -EPIPE;
+		if (!*timeo_p)
+			return -EAGAIN;
+		if (signal_pending(tsk))
+			return sock_intr_errno(*timeo_p);
+
+		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+		sk->sk_write_pending++;
+		if (sk_wait_event(sk, timeo_p,
+				  !((1 << sk->sk_state) & 
+				    ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))))
+			break;
+		finish_wait(sk->sk_sleep, &wait);
+		sk->sk_write_pending--;
+	}
+	return 0;
+}
+
+EXPORT_SYMBOL(sk_stream_wait_connect);

net/ipv4/tcp.c

@@ -636,46 +636,11 @@ static void tcp_listen_stop (struct sock *sk)
 	BUG_TRAP(!sk->sk_ack_backlog);
 }
 
-/*
- *	Wait for a socket to get into the connected state
- *
- *	Note: Must be called with the socket locked.
- */
-static int wait_for_tcp_connect(struct sock *sk, int flags, long *timeo_p)
-{
-	struct tcp_opt *tp = tcp_sk(sk);
-	struct task_struct *tsk = current;
-	DEFINE_WAIT(wait);
-
-	while ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
-		if (sk->sk_err)
-			return sock_error(sk);
-		if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))
-			return -EPIPE;
-		if (!*timeo_p)
-			return -EAGAIN;
-		if (signal_pending(tsk))
-			return sock_intr_errno(*timeo_p);
-
-		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
-		tp->write_pending++;
-
-		release_sock(sk);
-		*timeo_p = schedule_timeout(*timeo_p);
-		lock_sock(sk);
-
-		finish_wait(sk->sk_sleep, &wait);
-		tp->write_pending--;
-	}
-	return 0;
-}
-
 /*
  *	Wait for more memory for a socket
  */
 static int wait_for_tcp_memory(struct sock *sk, long *timeo)
 {
-	struct tcp_opt *tp = tcp_sk(sk);
 	int err = 0;
 	long vm_wait = 0;
 	long current_timeo = *timeo;
@@ -700,12 +665,12 @@ static int wait_for_tcp_memory(struct sock *sk, long *timeo)
 			break;
 
 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
-		tp->write_pending++;
+		sk->sk_write_pending++;
 		release_sock(sk);
 		if (!sk_stream_memory_free(sk) || vm_wait)
 			current_timeo = schedule_timeout(current_timeo);
 		lock_sock(sk);
-		tp->write_pending--;
+		sk->sk_write_pending--;
 
 		if (vm_wait) {
 			vm_wait -= current_timeo;
@@ -812,7 +777,7 @@ static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffse
 
 	/* Wait for a connection to finish. */
 	if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
-		if ((err = wait_for_tcp_connect(sk, 0, &timeo)) != 0)
+		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 			goto out_err;
 
 	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
@@ -965,7 +930,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 
 	/* Wait for a connection to finish. */
 	if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
-		if ((err = wait_for_tcp_connect(sk, flags, &timeo)) != 0)
+		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 			goto out_err;
 
 	/* This should be in poll */

net/ipv4/tcp_input.c

@@ -4474,7 +4474,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 			sk_wake_async(sk, 0, POLL_OUT);
 		}
 
-		if (tp->write_pending || tp->defer_accept || tp->ack.pingpong) {
+		if (sk->sk_write_pending || tp->defer_accept || tp->ack.pingpong) {
 			/* Save one ACK. Data will be ready after
 			 * several ticks, if write_pending is set.
 			 *