[TCP]: Fix quick-ack decrementing with TSO.

On each packet output, we call tcp_dec_quickack_mode() if the ACK flag is set. It drops tp->ack.quick until it hits zero, at which time we deflate the ATO value. When doing TSO, we are emitting multiple packets with ACK set, so we should decrement tp->ack.quick that many segments. Note that, unlike this case, tcp_enter_cwr() should not take the tcp_skb_pcount(skb) into consideration. That function, one time, readjusts tp->snd_cwnd and moves into TCP_CA_CWR state. Signed-off-by: David S. Miller <[email protected]>
caleberi · Jul 5, 2005 · fc6415b · fc6415b
1 parent c65f7f0
commit fc6415b
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Showing 2 changed files with 12 additions and 7 deletions.
diff --git a/include/net/tcp.h b/include/net/tcp.h
@@ -721,11 +721,16 @@ static inline int tcp_ack_scheduled(struct tcp_sock *tp)
 	return tp->ack.pending&TCP_ACK_SCHED;
 }
 
-static __inline__ void tcp_dec_quickack_mode(struct tcp_sock *tp)
+static __inline__ void tcp_dec_quickack_mode(struct tcp_sock *tp, unsigned int pkts)
 {
-	if (tp->ack.quick && --tp->ack.quick == 0) {
-		/* Leaving quickack mode we deflate ATO. */
-		tp->ack.ato = TCP_ATO_MIN;
+	if (tp->ack.quick) {
+		if (pkts >= tp->ack.quick) {
+			tp->ack.quick = 0;
+
+			/* Leaving quickack mode we deflate ATO. */
+			tp->ack.ato = TCP_ATO_MIN;
+		} else
+			tp->ack.quick -= pkts;
 	}
 }
 

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
@@ -140,11 +140,11 @@ static inline void tcp_event_data_sent(struct tcp_sock *tp,
 		tp->ack.pingpong = 1;
 }
 
-static __inline__ void tcp_event_ack_sent(struct sock *sk)
+static __inline__ void tcp_event_ack_sent(struct sock *sk, unsigned int pkts)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
-	tcp_dec_quickack_mode(tp);
+	tcp_dec_quickack_mode(tp, pkts);
 	tcp_clear_xmit_timer(sk, TCP_TIME_DACK);
 }
 
@@ -355,7 +355,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb)
 		tp->af_specific->send_check(sk, th, skb->len, skb);
 
 		if (tcb->flags & TCPCB_FLAG_ACK)
-			tcp_event_ack_sent(sk);
+			tcp_event_ack_sent(sk, tcp_skb_pcount(skb));
 
 		if (skb->len != tcp_header_size)
 			tcp_event_data_sent(tp, skb, sk);