Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (21 commits)
  dca: disable dca on IOAT ver.3.0 multiple-IOH platforms
  netpoll: Disable IRQ around RCU dereference in netpoll_rx
  sctp: Do not reset the packet during sctp_packet_config().
  net/llc: storing negative error codes in unsigned short
  MAINTAINERS: move atlx discussions to netdev
  drivers/net/cxgb3/cxgb3_main.c: prevent reading uninitialized stack memory
  drivers/net/eql.c: prevent reading uninitialized stack memory
  drivers/net/usb/hso.c: prevent reading uninitialized memory
  xfrm: dont assume rcu_read_lock in xfrm_output_one()
  r8169: Handle rxfifo errors on 8168 chips
  3c59x: Remove atomic context inside vortex_{set|get}_wol
  tcp: Prevent overzealous packetization by SWS logic.
  net: RPS needs to depend upon USE_GENERIC_SMP_HELPERS
  phylib: fix PAL state machine restart on resume
  net: use rcu_barrier() in rollback_registered_many
  bonding: correctly process non-linear skbs
  ipv4: enable getsockopt() for IP_NODEFRAG
  ipv4: force_igmp_version ignored when a IGMPv3 query received
  ppp: potential NULL dereference in ppp_mp_explode()
  net/llc: make opt unsigned in llc_ui_setsockopt()
  ...

1 files changed, 16 insertions, 2 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index eaa9582779d0..3e4b33e36602 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;
 }