diff --git a/include/net/tcp.h b/include/net/tcp.h
index dba22fc1b065..364426a2be5a 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -991,7 +991,7 @@ static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
 
 static inline bool tcp_in_slow_start(const struct tcp_sock *tp)
 {
-	return tp->snd_cwnd <= tp->snd_ssthresh;
+	return tp->snd_cwnd < tp->snd_ssthresh;
 }
 
 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp)
diff --git a/net/ipv4/tcp_cdg.c b/net/ipv4/tcp_cdg.c
index 8c6fd3d5e40f..167b6a3e1b98 100644
--- a/net/ipv4/tcp_cdg.c
+++ b/net/ipv4/tcp_cdg.c
@@ -264,7 +264,7 @@ static void tcp_cdg_cong_avoid(struct sock *sk, u32 ack, u32 acked)
 	u32 prior_snd_cwnd;
 	u32 incr;
 
-	if (tp->snd_cwnd < tp->snd_ssthresh && hystart_detect)
+	if (tcp_in_slow_start(tp) && hystart_detect)
 		tcp_cdg_hystart_update(sk);
 
 	if (after(ack, ca->rtt_seq) && ca->rtt.v64) {
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 654729a8cb23..a2ed23c595cf 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -365,10 +365,8 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
  */
 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked)
 {
-	u32 cwnd = tp->snd_cwnd + acked;
+	u32 cwnd = min(tp->snd_cwnd + acked, tp->snd_ssthresh);
 
-	if (cwnd > tp->snd_ssthresh)
-		cwnd = tp->snd_ssthresh + 1;
 	acked -= cwnd - tp->snd_cwnd;
 	tp->snd_cwnd = min(cwnd, tp->snd_cwnd_clamp);
 
diff --git a/net/ipv4/tcp_hybla.c b/net/ipv4/tcp_hybla.c
index f963b274f2b0..083831e359df 100644
--- a/net/ipv4/tcp_hybla.c
+++ b/net/ipv4/tcp_hybla.c
@@ -112,7 +112,7 @@ static void hybla_cong_avoid(struct sock *sk, u32 ack, u32 acked)
 
 	rho_fractions = ca->rho_3ls - (ca->rho << 3);
 
-	if (tp->snd_cwnd < tp->snd_ssthresh) {
+	if (tcp_in_slow_start(tp)) {
 		/*
 		 * slow start
 		 *      INC = 2^RHO - 1