netdev - [PATCH net-next 5/6] tcp: remove CA_ACK

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Date:   Sun, 30 Jul 2017 03:57:22 +0200
From:   Florian Westphal <fw@...len.de>
To:     <netdev@...r.kernel.org>
Cc:     Florian Westphal <fw@...len.de>
Subject: [PATCH net-next 5/6] tcp: remove CA_ACK_SLOWPATH

re-indent tcp_ack, and remove CA_ACK_SLOWPATH; it is always set now.

Signed-off-by: Florian Westphal <fw@...len.de>
---
 include/net/tcp.h       |  5 ++---
 net/ipv4/tcp_input.c    | 35 ++++++++++++++++-------------------
 net/ipv4/tcp_westwood.c | 31 ++++---------------------------
 3 files changed, 22 insertions(+), 49 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 8f11b82b5b5a..3ecb62811004 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -880,9 +880,8 @@ enum tcp_ca_event {
 
 /* Information about inbound ACK, passed to cong_ops->in_ack_event() */
 enum tcp_ca_ack_event_flags {
-	CA_ACK_SLOWPATH		= (1 << 0),	/* In slow path processing */
-	CA_ACK_WIN_UPDATE	= (1 << 1),	/* ACK updated window */
-	CA_ACK_ECE		= (1 << 2),	/* ECE bit is set on ack */
+	CA_ACK_WIN_UPDATE	= (1 << 0),	/* ACK updated window */
+	CA_ACK_ECE		= (1 << 1),	/* ECE bit is set on ack */
 };
 
 /*
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index bfde9d7d210e..af0a98d54b62 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3547,6 +3547,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	u32 lost = tp->lost;
 	int acked = 0; /* Number of packets newly acked */
 	int rexmit = REXMIT_NONE; /* Flag to (re)transmit to recover losses */
+	u32 ack_ev_flags = 0;
 
 	sack_state.first_sackt = 0;
 	sack_state.rate = &rs;
@@ -3590,30 +3591,26 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	if (flag & FLAG_UPDATE_TS_RECENT)
 		tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
 
-	{
-		u32 ack_ev_flags = CA_ACK_SLOWPATH;
-
-		if (ack_seq != TCP_SKB_CB(skb)->end_seq)
-			flag |= FLAG_DATA;
-		else
-			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPUREACKS);
+	if (ack_seq != TCP_SKB_CB(skb)->end_seq)
+		flag |= FLAG_DATA;
+	else
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPUREACKS);
 
-		flag |= tcp_ack_update_window(sk, skb, ack, ack_seq);
+	flag |= tcp_ack_update_window(sk, skb, ack, ack_seq);
 
-		if (TCP_SKB_CB(skb)->sacked)
-			flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una,
-							&sack_state);
+	if (TCP_SKB_CB(skb)->sacked)
+		flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una,
+						&sack_state);
 
-		if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb))) {
-			flag |= FLAG_ECE;
-			ack_ev_flags |= CA_ACK_ECE;
-		}
+	if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb))) {
+		flag |= FLAG_ECE;
+		ack_ev_flags = CA_ACK_ECE;
+	}
 
-		if (flag & FLAG_WIN_UPDATE)
-			ack_ev_flags |= CA_ACK_WIN_UPDATE;
+	if (flag & FLAG_WIN_UPDATE)
+		ack_ev_flags |= CA_ACK_WIN_UPDATE;
 
-		tcp_in_ack_event(sk, ack_ev_flags);
-	}
+	tcp_in_ack_event(sk, ack_ev_flags);
 
 	/* We passed data and got it acked, remove any soft error
 	 * log. Something worked...
diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c
index bec9cafbe3f9..e5de84310949 100644
--- a/net/ipv4/tcp_westwood.c
+++ b/net/ipv4/tcp_westwood.c
@@ -154,24 +154,6 @@ static inline void update_rtt_min(struct westwood *w)
 }
 
 /*
- * @westwood_fast_bw
- * It is called when we are in fast path. In particular it is called when
- * header prediction is successful. In such case in fact update is
- * straight forward and doesn't need any particular care.
- */
-static inline void westwood_fast_bw(struct sock *sk)
-{
-	const struct tcp_sock *tp = tcp_sk(sk);
-	struct westwood *w = inet_csk_ca(sk);
-
-	westwood_update_window(sk);
-
-	w->bk += tp->snd_una - w->snd_una;
-	w->snd_una = tp->snd_una;
-	update_rtt_min(w);
-}
-
-/*
  * @westwood_acked_count
  * This function evaluates cumul_ack for evaluating bk in case of
  * delayed or partial acks.
@@ -223,17 +205,12 @@ static u32 tcp_westwood_bw_rttmin(const struct sock *sk)
 
 static void tcp_westwood_ack(struct sock *sk, u32 ack_flags)
 {
-	if (ack_flags & CA_ACK_SLOWPATH) {
-		struct westwood *w = inet_csk_ca(sk);
-
-		westwood_update_window(sk);
-		w->bk += westwood_acked_count(sk);
+	struct westwood *w = inet_csk_ca(sk);
 
-		update_rtt_min(w);
-		return;
-	}
+	westwood_update_window(sk);
+	w->bk += westwood_acked_count(sk);
 
-	westwood_fast_bw(sk);
+	update_rtt_min(w);
 }
 
 static void tcp_westwood_event(struct sock *sk, enum tcp_ca_event event)
-- 
2.13.0