[NET] Introduce sk_reset_timer and sk_stop_timer

This makes the best practices already in place in bluetooth
and tcp/ip available for all protocols, i.e. references must
be managed when associating timers with struct sock instances,
also makes the code a bit more clean.
Signed-off-by: Arnaldo Carvalho de Melo <acme@conectiva.com.br>

include/net/sock.h

@@ -898,6 +898,11 @@ static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
 	atomic_add(skb->truesize, &sk->sk_rmem_alloc);
 }
 
+extern void sk_reset_timer(struct sock *sk, struct timer_list* timer,
+			   unsigned long expires);
+
+extern void sk_stop_timer(struct sock *sk, struct timer_list* timer);
+
 static inline int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
 	int err = 0;

include/net/tcp.h

@@ -989,9 +989,7 @@ static inline void tcp_clear_xmit_timer(struct sock *sk, int what)
 		tp->pending = 0;
 
 #ifdef TCP_CLEAR_TIMERS
-		if (timer_pending(&tp->retransmit_timer) &&
-		    del_timer(&tp->retransmit_timer))
-			__sock_put(sk);
+		sk_stop_timer(sk, &tp->retransmit_timer);
 #endif
 		break;
 	case TCP_TIME_DACK:
@@ -999,9 +997,7 @@ static inline void tcp_clear_xmit_timer(struct sock *sk, int what)
 		tp->ack.pending = 0;
 
 #ifdef TCP_CLEAR_TIMERS
-		if (timer_pending(&tp->delack_timer) &&
-		    del_timer(&tp->delack_timer))
-			__sock_put(sk);
+		sk_stop_timer(sk, &tp->delack_timer);
 #endif
 		break;
 	default:
@@ -1030,15 +1026,13 @@ static inline void tcp_reset_xmit_timer(struct sock *sk, int what, unsigned long
 	case TCP_TIME_PROBE0:
 		tp->pending = what;
 		tp->timeout = jiffies+when;
-		if (!mod_timer(&tp->retransmit_timer, tp->timeout))
-			sock_hold(sk);
+		sk_reset_timer(sk, &tp->retransmit_timer, tp->timeout);
 		break;
 
 	case TCP_TIME_DACK:
 		tp->ack.pending |= TCP_ACK_TIMER;
 		tp->ack.timeout = jiffies+when;
-		if (!mod_timer(&tp->delack_timer, tp->ack.timeout))
-			sock_hold(sk);
+		sk_reset_timer(sk, &tp->delack_timer, tp->ack.timeout);
 		break;
 
 	default:

net/bluetooth/l2cap.c

@@ -95,17 +95,13 @@ static void l2cap_sock_timeout(unsigned long arg)
 static void l2cap_sock_set_timer(struct sock *sk, long timeout)
 {
 	BT_DBG("sk %p state %d timeout %ld", sk, sk->sk_state, timeout);
-
-	if (!mod_timer(&sk->sk_timer, jiffies + timeout))
-		sock_hold(sk);
+	sk_reset_timer(sk, &sk->sk_timer, jiffies + timeout);
 }
 
 static void l2cap_sock_clear_timer(struct sock *sk)
 {
 	BT_DBG("sock %p state %d", sk, sk->sk_state);
-
-	if (timer_pending(&sk->sk_timer) && del_timer(&sk->sk_timer))
-		__sock_put(sk);
+	sk_stop_timer(sk, &sk->sk_timer);
 }
 
 static void l2cap_sock_init_timer(struct sock *sk)

net/bluetooth/sco.c

@@ -91,17 +91,13 @@ static void sco_sock_timeout(unsigned long arg)
 static void sco_sock_set_timer(struct sock *sk, long timeout)
 {
 	BT_DBG("sock %p state %d timeout %ld", sk, sk->sk_state, timeout);
-
-	if (!mod_timer(&sk->sk_timer, jiffies + timeout))
-		sock_hold(sk);
+	sk_reset_timer(sk, &sk->sk_timer, jiffies + timeout);
 }
 
 static void sco_sock_clear_timer(struct sock *sk)
 {
 	BT_DBG("sock %p state %d", sk, sk->sk_state);
-
-	if (timer_pending(&sk->sk_timer) && del_timer(&sk->sk_timer))
-		__sock_put(sk);
+	sk_stop_timer(sk, &sk->sk_timer);
 }
 
 static void sco_sock_init_timer(struct sock *sk)

net/core/sock.c

@@ -1099,6 +1099,23 @@ void sk_send_sigurg(struct sock *sk)
 			sk_wake_async(sk, 3, POLL_PRI);
 }
 
+void sk_reset_timer(struct sock *sk, struct timer_list* timer,
+		    unsigned long expires)
+{
+	if (!mod_timer(timer, expires))
+		sock_hold(sk);
+}
+
+EXPORT_SYMBOL(sk_reset_timer);
+
+void sk_stop_timer(struct sock *sk, struct timer_list* timer)
+{
+	if (timer_pending(timer) && del_timer(timer))
+		__sock_put(sk);
+}
+
+EXPORT_SYMBOL(sk_stop_timer);
+
 void sock_init_data(struct socket *sock, struct sock *sk)
 {
 	skb_queue_head_init(&sk->sk_receive_queue);

net/ipv4/tcp_output.c

@@ -1389,8 +1389,7 @@ void tcp_send_delayed_ack(struct sock *sk)
 	}
 	tp->ack.pending |= TCP_ACK_SCHED|TCP_ACK_TIMER;
 	tp->ack.timeout = timeout;
-	if (!mod_timer(&tp->delack_timer, timeout))
-		sock_hold(sk);
+	sk_reset_timer(sk, &tp->delack_timer, timeout);
 }
 
 /* This routine sends an ack and also updates the window. */

net/ipv4/tcp_timer.c

@@ -68,18 +68,13 @@ void tcp_clear_xmit_timers(struct sock *sk)
 	struct tcp_opt *tp = tcp_sk(sk);
 
 	tp->pending = 0;
-	if (timer_pending(&tp->retransmit_timer) &&
-	    del_timer(&tp->retransmit_timer))
-		__sock_put(sk);
+	sk_stop_timer(sk, &tp->retransmit_timer);
 
 	tp->ack.pending = 0;
 	tp->ack.blocked = 0;
-	if (timer_pending(&tp->delack_timer) &&
-	    del_timer(&tp->delack_timer))
-		__sock_put(sk);
+	sk_stop_timer(sk, &tp->delack_timer);
 
-	if (timer_pending(&sk->sk_timer) && del_timer(&sk->sk_timer))
-		__sock_put(sk);
+	sk_stop_timer(sk, &sk->sk_timer);
 }
 
 static void tcp_write_err(struct sock *sk)
@@ -218,8 +213,7 @@ static void tcp_delack_timer(unsigned long data)
 		/* Try again later. */
 		tp->ack.blocked = 1;
 		NET_INC_STATS_BH(DelayedACKLocked);
-		if (!mod_timer(&tp->delack_timer, jiffies + TCP_DELACK_MIN))
-			sock_hold(sk);
+		sk_reset_timer(sk, &tp->delack_timer, jiffies + TCP_DELACK_MIN);
 		goto out_unlock;
 	}
 
@@ -229,8 +223,7 @@ static void tcp_delack_timer(unsigned long data)
 		goto out;
 
 	if (time_after(tp->ack.timeout, jiffies)) {
-		if (!mod_timer(&tp->delack_timer, tp->ack.timeout))
-			sock_hold(sk);
+		sk_reset_timer(sk, &tp->delack_timer, tp->ack.timeout);
 		goto out;
 	}
 	tp->ack.pending &= ~TCP_ACK_TIMER;
@@ -429,8 +422,7 @@ static void tcp_write_timer(unsigned long data)
 	bh_lock_sock(sk);
 	if (sock_owned_by_user(sk)) {
 		/* Try again later */
-		if (!mod_timer(&tp->retransmit_timer, jiffies + (HZ/20)))
-			sock_hold(sk);
+		sk_reset_timer(sk, &tp->retransmit_timer, jiffies + (HZ / 20));
 		goto out_unlock;
 	}
 
@@ -438,8 +430,7 @@ static void tcp_write_timer(unsigned long data)
 		goto out;
 
 	if (time_after(tp->timeout, jiffies)) {
-		if (!mod_timer(&tp->retransmit_timer, tp->timeout))
-			sock_hold(sk);
+		sk_reset_timer(sk, &tp->retransmit_timer, tp->timeout);
 		goto out;
 	}
 
@@ -557,14 +548,12 @@ static void tcp_synack_timer(struct sock *sk)
 
 void tcp_delete_keepalive_timer (struct sock *sk)
 {
-	if (timer_pending(&sk->sk_timer) && del_timer (&sk->sk_timer))
-		__sock_put(sk);
+	sk_stop_timer(sk, &sk->sk_timer);
 }
 
 void tcp_reset_keepalive_timer (struct sock *sk, unsigned long len)
 {
-	if (!mod_timer(&sk->sk_timer, jiffies + len))
-		sock_hold(sk);
+	sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
 }
 
 void tcp_set_keepalive(struct sock *sk, int val)