tcp: Add tcp_retransmit_stamp() helper routine

Create a seperate helper routine as per Neal Cardwells suggestion. To
be used by the final commit in this series and retransmits_timed_out().

Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 8 deletions

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index fa34984d0b12..d212f183dd2d 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -22,6 +22,20 @@
 #include <linux/gfp.h>
 #include <net/tcp.h>
 
+u32 tcp_retransmit_stamp(const struct sock *sk)
+{
+        u32 start_ts = tcp_sk(sk)->retrans_stamp;
+
+        if (unlikely(!start_ts)) {
+                struct sk_buff *head = tcp_rtx_queue_head(sk);
+
+                if (!head)
+                        return 0;
+                start_ts = tcp_skb_timestamp(head);
+        }
+        return start_ts;
+}
+
 /**
  *  tcp_write_err() - close socket and save error info
  *  @sk:  The socket the error has appeared on.
@@ -166,14 +180,9 @@ static bool retransmits_timed_out(struct sock *sk,
         if (!inet_csk(sk)->icsk_retransmits)
                 return false;
 
-        start_ts = tcp_sk(sk)->retrans_stamp;
-        if (unlikely(!start_ts)) {
-                struct sk_buff *head = tcp_rtx_queue_head(sk);
-
-                if (!head)
-                        return false;
-                start_ts = tcp_skb_timestamp(head);
-        }
+        start_ts = tcp_retransmit_stamp(sk);
+        if (!start_ts)
+                return false;
 
         if (likely(timeout == 0)) {
                 linear_backoff_thresh = ilog2(TCP_RTO_MAX/rto_base);