1 files changed, 20 insertions, 25 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9579e1a5a144..86b5fa72ff9e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2430,12 +2430,14 @@ static void tcp_init_cwnd_reduction(struct sock *sk, const bool set_ssthresh)
 	TCP_ECN_queue_cwr(tp);
 }
 
-static void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked,
+static void tcp_cwnd_reduction(struct sock *sk, const int prior_unsacked,
 			       int fast_rexmit)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	int sndcnt = 0;
 	int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp);
+	int newly_acked_sacked = prior_unsacked -
+				 (tp->packets_out - tp->sacked_out);
 
 	tp->prr_delivered += newly_acked_sacked;
 	if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) {
@@ -2492,7 +2494,7 @@ static void tcp_try_keep_open(struct sock *sk)
 	}
 }
 
-static void tcp_try_to_open(struct sock *sk, int flag, int newly_acked_sacked)
+static void tcp_try_to_open(struct sock *sk, int flag, const int prior_unsacked)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
@@ -2509,7 +2511,7 @@ static void tcp_try_to_open(struct sock *sk, int flag, int newly_acked_sacked)
 		if (inet_csk(sk)->icsk_ca_state != TCP_CA_Open)
 			tcp_moderate_cwnd(tp);
 	} else {
-		tcp_cwnd_reduction(sk, newly_acked_sacked, 0);
+		tcp_cwnd_reduction(sk, prior_unsacked, 0);
 	}
 }
 
@@ -2678,15 +2680,14 @@ static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack)
  * It does _not_ decide what to send, it is made in function
  * tcp_xmit_retransmit_queue().
  */
-static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
-				  int prior_sacked, int prior_packets,
+static void tcp_fastretrans_alert(struct sock *sk, const int acked,
+				  const int prior_unsacked,
 				  bool is_dupack, int flag)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
 	int do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) &&
 				    (tcp_fackets_out(tp) > tp->reordering));
-	int newly_acked_sacked = 0;
 	int fast_rexmit = 0;
 
 	if (WARN_ON(!tp->packets_out && tp->sacked_out))
@@ -2739,9 +2740,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
 			if (tcp_is_reno(tp) && is_dupack)
 				tcp_add_reno_sack(sk);
 		} else
-			do_lost = tcp_try_undo_partial(sk, pkts_acked);
-		newly_acked_sacked = prior_packets - tp->packets_out +
-				     tp->sacked_out - prior_sacked;
+			do_lost = tcp_try_undo_partial(sk, acked);
 		break;
 	case TCP_CA_Loss:
 		tcp_process_loss(sk, flag, is_dupack);
@@ -2755,14 +2754,12 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
 			if (is_dupack)
 				tcp_add_reno_sack(sk);
 		}
-		newly_acked_sacked = prior_packets - tp->packets_out +
-				     tp->sacked_out - prior_sacked;
 
 		if (icsk->icsk_ca_state <= TCP_CA_Disorder)
 			tcp_try_undo_dsack(sk);
 
 		if (!tcp_time_to_recover(sk, flag)) {
-			tcp_try_to_open(sk, flag, newly_acked_sacked);
+			tcp_try_to_open(sk, flag, prior_unsacked);
 			return;
 		}
 
@@ -2784,7 +2781,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
 
 	if (do_lost)
 		tcp_update_scoreboard(sk, fast_rexmit);
-	tcp_cwnd_reduction(sk, newly_acked_sacked, fast_rexmit);
+	tcp_cwnd_reduction(sk, prior_unsacked, fast_rexmit);
 	tcp_xmit_retransmit_queue(sk);
 }
 
@@ -3268,9 +3265,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	u32 prior_in_flight;
 	u32 prior_fackets;
 	int prior_packets = tp->packets_out;
-	int prior_sacked = tp->sacked_out;
-	int pkts_acked = 0;
-	int previous_packets_out = 0;
+	const int prior_unsacked = tp->packets_out - tp->sacked_out;
+	int acked = 0; /* Number of packets newly acked */
 
 	/* If the ack is older than previous acks
 	 * then we can probably ignore it.
@@ -3345,18 +3341,17 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 		goto no_queue;
 
 	/* See if we can take anything off of the retransmit queue. */
-	previous_packets_out = tp->packets_out;
+	acked = tp->packets_out;
 	flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una);
-
-	pkts_acked = previous_packets_out - tp->packets_out;
+	acked -= tp->packets_out;
 
 	if (tcp_ack_is_dubious(sk, flag)) {
 		/* Advance CWND, if state allows this. */
 		if ((flag & FLAG_DATA_ACKED) && tcp_may_raise_cwnd(sk, flag))
 			tcp_cong_avoid(sk, ack, prior_in_flight);
 		is_dupack = !(flag & (FLAG_SND_UNA_ADVANCED | FLAG_NOT_DUP));
-		tcp_fastretrans_alert(sk, pkts_acked, prior_sacked,
-				      prior_packets, is_dupack, flag);
+		tcp_fastretrans_alert(sk, acked, prior_unsacked,
+				      is_dupack, flag);
 	} else {
 		if (flag & FLAG_DATA_ACKED)
 			tcp_cong_avoid(sk, ack, prior_in_flight);
@@ -3378,8 +3373,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 no_queue:
 	/* If data was DSACKed, see if we can undo a cwnd reduction. */
 	if (flag & FLAG_DSACKING_ACK)
-		tcp_fastretrans_alert(sk, pkts_acked, prior_sacked,
-				      prior_packets, is_dupack, flag);
+		tcp_fastretrans_alert(sk, acked, prior_unsacked,
+				      is_dupack, flag);
 	/* If this ack opens up a zero window, clear backoff.  It was
 	 * being used to time the probes, and is probably far higher than
 	 * it needs to be for normal retransmission.
@@ -3401,8 +3396,8 @@ old_ack:
 	 */
 	if (TCP_SKB_CB(skb)->sacked) {
 		flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una);
-		tcp_fastretrans_alert(sk, pkts_acked, prior_sacked,
-				      prior_packets, is_dupack, flag);
+		tcp_fastretrans_alert(sk, acked, prior_unsacked,
+				      is_dupack, flag);
 	}
 
 	SOCK_DEBUG(sk, "Ack %u before %u:%u\n", ack, tp->snd_una, tp->snd_nxt);