2 files changed, 13 insertions, 2 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index ad2021ccc55a..9d5078bd23a3 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -248,6 +248,7 @@ struct tcp_sock {
         /* inet_connection_sock has to be the first member of tcp_sock */
         struct inet_connection_sock     inet_conn;
         u16     tcp_header_len; /* Bytes of tcp header to send          */
+        u16     xmit_size_goal_segs; /* Goal for segmenting output packets */
 
 /*
  *      Header prediction flags
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 886596ff0aae..0db9f3b984f7 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -665,7 +665,7 @@ static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
                                        int large_allowed)
 {
         struct tcp_sock *tp = tcp_sk(sk);
-        u32 xmit_size_goal;
+        u32 xmit_size_goal, old_size_goal;
 
         xmit_size_goal = mss_now;
 
@@ -676,7 +676,17 @@ static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
                                   tp->tcp_header_len);
 
                 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
-                xmit_size_goal -= (xmit_size_goal % mss_now);
+
+                /* We try hard to avoid divides here */
+                old_size_goal = tp->xmit_size_goal_segs * mss_now;
+
+                if (likely(old_size_goal <= xmit_size_goal &&
+                           old_size_goal + mss_now > xmit_size_goal)) {
+                        xmit_size_goal = old_size_goal;
+                } else {
+                        tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
+                        xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
+                }
         }
 
         return xmit_size_goal;