1 files changed, 31 insertions, 9 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 8327e5e86d15..0a4cd24b6578 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -887,6 +887,7 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         struct sk_buff *skb;
+        unsigned int tso_segs, cwnd_quota;
         int sent_pkts;
 
         /* If we are closed, the bytes will have to remain here.
@@ -896,19 +897,31 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle)
         if (unlikely(sk->sk_state == TCP_CLOSE))
                 return 0;
 
+        skb = sk->sk_send_head;
+        if (unlikely(!skb))
+                return 0;
+
+        tso_segs = tcp_init_tso_segs(sk, skb);
+        cwnd_quota = tcp_cwnd_test(tp, skb);
         sent_pkts = 0;
-        while ((skb = sk->sk_send_head) &&
-               tcp_snd_test(sk, skb, mss_now,
-                            tcp_skb_is_last(sk, skb) ? nonagle :
-                            TCP_NAGLE_PUSH)) {
-                if (skb->len > mss_now) {
-                        if (tcp_fragment(sk, skb, mss_now))
+
+        while (cwnd_quota >= tso_segs) {
+                if (unlikely(!tcp_nagle_test(tp, skb, mss_now,
+                                             (tcp_skb_is_last(sk, skb) ?
+                                              nonagle : TCP_NAGLE_PUSH))))
+                        break;
+
+                if (unlikely(!tcp_snd_wnd_test(tp, skb, mss_now)))
+                        break;
+
+                if (unlikely(skb->len > mss_now)) {
+                        if (unlikely(tcp_fragment(sk, skb,  mss_now)))
                                 break;
                 }
 
                 TCP_SKB_CB(skb)->when = tcp_time_stamp;
                 tcp_tso_set_push(skb);
-                if (tcp_transmit_skb(sk, skb_clone(skb, GFP_ATOMIC)))
+                if (unlikely(tcp_transmit_skb(sk, skb_clone(skb, GFP_ATOMIC))))
                         break;
 
                 /* Advance the send_head.  This one is sent out.
@@ -917,10 +930,19 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle)
                 update_send_head(sk, tp, skb);
 
                 tcp_minshall_update(tp, mss_now, skb);
-                sent_pkts = 1;
+                sent_pkts++;
+
+                /* Do not optimize this to use tso_segs. If we chopped up
+                 * the packet above, tso_segs will no longer be valid.
+                 */
+                cwnd_quota -= tcp_skb_pcount(skb);
+                skb = sk->sk_send_head;
+                if (!skb)
+                        break;
+                tso_segs = tcp_init_tso_segs(sk, skb);
         }
 
-        if (sent_pkts) {
+        if (likely(sent_pkts)) {
                 tcp_cwnd_validate(sk, tp);
                 return 0;
         }