tcp: Stalling connections: Move timeout calculation routine

This patch moves retransmits_timed_out() from include/net/tcp.h
to tcp_timer.c, where it is used.

Reported-by: Frederic Leroy <fredo@starox.org>
Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -1261,34 +1261,6 @@ static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_bu
 #define tcp_for_write_queue_from_safe(skb, tmp, sk)			\
 	skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
 
-/* This function calculates a "timeout" which is equivalent to the timeout of a
- * TCP connection after "boundary" unsucessful, exponentially backed-off
- * retransmissions with an initial RTO of TCP_RTO_MIN.
- */
-static inline bool retransmits_timed_out(struct sock *sk,
-					 unsigned int boundary)
-{
-	unsigned int timeout, linear_backoff_thresh;
-	unsigned int start_ts;
-
-	if (!inet_csk(sk)->icsk_retransmits)
-		return false;
-
-	if (unlikely(!tcp_sk(sk)->retrans_stamp))
-		start_ts = TCP_SKB_CB(tcp_write_queue_head(sk))->when;
-	else
-		start_ts = tcp_sk(sk)->retrans_stamp;
-
-	linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN);
-
-	if (boundary <= linear_backoff_thresh)
-		timeout = ((2 << boundary) - 1) * TCP_RTO_MIN;
-	else
-		timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN +
-			  (boundary - linear_backoff_thresh) * TCP_RTO_MAX;
-
-	return (tcp_time_stamp - start_ts) >= timeout;
-}
 
 static inline struct sk_buff *tcp_send_head(struct sock *sk)
 {

net/ipv4/tcp_timer.c

@@ -132,6 +132,35 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk)
 	}
 }
 
+/* This function calculates a "timeout" which is equivalent to the timeout of a
+ * TCP connection after "boundary" unsucessful, exponentially backed-off
+ * retransmissions with an initial RTO of TCP_RTO_MIN.
+ */
+static bool retransmits_timed_out(struct sock *sk,
+				  unsigned int boundary)
+{
+	unsigned int timeout, linear_backoff_thresh;
+	unsigned int start_ts;
+
+	if (!inet_csk(sk)->icsk_retransmits)
+		return false;
+
+	if (unlikely(!tcp_sk(sk)->retrans_stamp))
+		start_ts = TCP_SKB_CB(tcp_write_queue_head(sk))->when;
+	else
+		start_ts = tcp_sk(sk)->retrans_stamp;
+
+	linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN);
+
+	if (boundary <= linear_backoff_thresh)
+		timeout = ((2 << boundary) - 1) * TCP_RTO_MIN;
+	else
+		timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN +
+			  (boundary - linear_backoff_thresh) * TCP_RTO_MAX;
+
+	return (tcp_time_stamp - start_ts) >= timeout;
+}
+
 /* A write timeout has occurred. Process the after effects. */
 static int tcp_write_timeout(struct sock *sk)
 {