1 files changed, 21 insertions, 14 deletions

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index d8970ecfcfc8..8f1480808f90 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -114,13 +114,31 @@ static int tcp_orphan_retries(struct sock *sk, int alive)
         return retries;
 }
 
+static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk)
+{
+        int mss;
+
+        /* Black hole detection */
+        if (sysctl_tcp_mtu_probing) {
+                if (!icsk->icsk_mtup.enabled) {
+                        icsk->icsk_mtup.enabled = 1;
+                        tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
+                } else {
+                        struct tcp_sock *tp = tcp_sk(sk);
+                        mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low)/2;
+                        mss = min(sysctl_tcp_base_mss, mss);
+                        mss = max(mss, 68 - tp->tcp_header_len);
+                        icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
+                        tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
+                }
+        }
+}
+
 /* A write timeout has occurred. Process the after effects. */
 static int tcp_write_timeout(struct sock *sk)
 {
         struct inet_connection_sock *icsk = inet_csk(sk);
-        struct tcp_sock *tp = tcp_sk(sk);
         int retry_until;
-        int mss;
 
         if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
                 if (icsk->icsk_retransmits)
@@ -129,18 +147,7 @@ static int tcp_write_timeout(struct sock *sk)
         } else {
                 if (icsk->icsk_retransmits >= sysctl_tcp_retries1) {
                         /* Black hole detection */
-                        if (sysctl_tcp_mtu_probing) {
-                                if (!icsk->icsk_mtup.enabled) {
-                                        icsk->icsk_mtup.enabled = 1;
-                                        tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
-                                } else {
-                                        mss = min(sysctl_tcp_base_mss,
-                                                  tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low)/2);
-                                        mss = max(mss, 68 - tp->tcp_header_len);
-                                        icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
-                                        tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
-                                }
-                        }
+                        tcp_mtu_probing(icsk, sk);
 
                         dst_negative_advice(&sk->sk_dst_cache);
                 }