2 files changed, 20 insertions, 6 deletions

diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 791d5109f34c..50d8009be86c 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -63,20 +63,20 @@ static inline bool netpoll_rx(struct sk_buff *skb)
         unsigned long flags;
         bool ret = false;
 
-        rcu_read_lock_bh();
+        local_irq_save(flags);
         npinfo = rcu_dereference_bh(skb->dev->npinfo);
 
         if (!npinfo || (list_empty(&npinfo->rx_np) && !npinfo->rx_flags))
                 goto out;
 
-        spin_lock_irqsave(&npinfo->rx_lock, flags);
+        spin_lock(&npinfo->rx_lock);
         /* check rx_flags again with the lock held */
         if (npinfo->rx_flags && __netpoll_rx(skb))
                 ret = true;
-        spin_unlock_irqrestore(&npinfo->rx_lock, flags);
+        spin_unlock(&npinfo->rx_lock);
 
 out:
-        rcu_read_unlock_bh();
+        local_irq_restore(flags);
         return ret;
 }
 
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;
 }