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-rw-r--r--include/net/tcp.h18
1 files changed, 16 insertions, 2 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index eaa9582779d..3e4b33e3660 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -475,8 +475,22 @@ extern unsigned int tcp_current_mss(struct sock *sk);
/* Bound MSS / TSO packet size with the half of the window */
static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
{
- if (tp->max_window && pktsize > (tp->max_window >> 1))
- return max(tp->max_window >> 1, 68U - tp->tcp_header_len);
+ int cutoff;
+
+ /* When peer uses tiny windows, there is no use in packetizing
+ * to sub-MSS pieces for the sake of SWS or making sure there
+ * are enough packets in the pipe for fast recovery.
+ *
+ * On the other hand, for extremely large MSS devices, handling
+ * smaller than MSS windows in this way does make sense.
+ */
+ if (tp->max_window >= 512)
+ cutoff = (tp->max_window >> 1);
+ else
+ cutoff = tp->max_window;
+
+ if (cutoff && pktsize > cutoff)
+ return max_t(int, cutoff, 68U - tp->tcp_header_len);
else
return pktsize;
}