tcp: remove unused min_cwnd member of tcp_congestion_ops

Commit 684bad110757 "tcp: use PRR to reduce cwin in CWR state" removed all
calls to min_cwnd, so we can safely remove it.
Also, remove tcp_reno_min_cwnd because it was only used for min_cwnd.

Signed-off-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Joe Maples <joe@frap129.org>

Conflicts:
	include/net/tcp.h

11 files changed, 1 insertions, 22 deletions

diff --git a/Documentation/networking/tcp.txt b/Documentation/networking/tcp.txt
index 7d11bb5dc..bdc4c0db5 100644
--- a/Documentation/networking/tcp.txt
+++ b/Documentation/networking/tcp.txt
@@ -30,7 +30,7 @@ A congestion control mechanism can be registered through functions in
 tcp_cong.c. The functions used by the congestion control mechanism are
 registered via passing a tcp_congestion_ops struct to
 tcp_register_congestion_control. As a minimum name, ssthresh,
-cong_avoid, min_cwnd must be valid.
+cong_avoid must be valid.
 
 Private data for a congestion control mechanism is stored in tp->ca_priv.
 tcp_ca(tp) returns a pointer to this space.  This is preallocated space - it
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 5c16c3cf9..8ba2f83ab 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -784,8 +784,6 @@ struct tcp_congestion_ops {
 
 	/* return slow start threshold (required) */
 	u32 (*ssthresh)(struct sock *sk);
-	/* lower bound for congestion window (optional) */
-	u32 (*min_cwnd)(const struct sock *sk);
 	/* do new cwnd calculation (required) */
 	void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
 	/* call before changing ca_state (optional) */
@@ -820,7 +818,6 @@ extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w);
 extern struct tcp_congestion_ops tcp_init_congestion_ops;
 extern u32 tcp_reno_ssthresh(struct sock *sk);
 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
-extern u32 tcp_reno_min_cwnd(const struct sock *sk);
 extern struct tcp_congestion_ops tcp_reno;
 
 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index ad7ab403f..76f218141 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -372,21 +372,12 @@ u32 tcp_reno_ssthresh(struct sock *sk)
 }
 EXPORT_SYMBOL_GPL(tcp_reno_ssthresh);
 
-/* Lower bound on congestion window with halving. */
-u32 tcp_reno_min_cwnd(const struct sock *sk)
-{
-	const struct tcp_sock *tp = tcp_sk(sk);
-	return tp->snd_ssthresh/2;
-}
-EXPORT_SYMBOL_GPL(tcp_reno_min_cwnd);
-
 struct tcp_congestion_ops tcp_reno = {
 	.flags		= TCP_CONG_NON_RESTRICTED,
 	.name		= "reno",
 	.owner		= THIS_MODULE,
 	.ssthresh	= tcp_reno_ssthresh,
 	.cong_avoid	= tcp_reno_cong_avoid,
-	.min_cwnd	= tcp_reno_min_cwnd,
 };
 
 /* Initial congestion control used (until SYN)
@@ -398,6 +389,5 @@ struct tcp_congestion_ops tcp_init_congestion_ops  = {
 	.owner		= THIS_MODULE,
 	.ssthresh	= tcp_reno_ssthresh,
 	.cong_avoid	= tcp_reno_cong_avoid,
-	.min_cwnd	= tcp_reno_min_cwnd,
 };
 EXPORT_SYMBOL_GPL(tcp_init_congestion_ops);
diff --git a/net/ipv4/tcp_highspeed.c b/net/ipv4/tcp_highspeed.c
index aecca5374..9a0b71086 100644
--- a/net/ipv4/tcp_highspeed.c
+++ b/net/ipv4/tcp_highspeed.c
@@ -161,7 +161,6 @@ static struct tcp_congestion_ops tcp_highspeed __read_mostly = {
 	.init		= hstcp_init,
 	.ssthresh	= hstcp_ssthresh,
 	.cong_avoid	= hstcp_cong_avoid,
-	.min_cwnd	= tcp_reno_min_cwnd,
 
 	.owner		= THIS_MODULE,
 	.name		= "highspeed"
diff --git a/net/ipv4/tcp_hybla.c b/net/ipv4/tcp_hybla.c
index b5100aaea..792c16072 100644
--- a/net/ipv4/tcp_hybla.c
+++ b/net/ipv4/tcp_hybla.c
@@ -164,7 +164,6 @@ static void hybla_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
 static struct tcp_congestion_ops tcp_hybla __read_mostly = {
 	.init		= hybla_init,
 	.ssthresh	= tcp_reno_ssthresh,
-	.min_cwnd	= tcp_reno_min_cwnd,
 	.cong_avoid	= hybla_cong_avoid,
 	.set_state	= hybla_state,
 
diff --git a/net/ipv4/tcp_illinois.c b/net/ipv4/tcp_illinois.c
index 6845012e6..8dc03ec75 100644
--- a/net/ipv4/tcp_illinois.c
+++ b/net/ipv4/tcp_illinois.c
@@ -326,7 +326,6 @@ static struct tcp_congestion_ops tcp_illinois __read_mostly = {
 	.flags		= TCP_CONG_RTT_STAMP,
 	.init		= tcp_illinois_init,
 	.ssthresh	= tcp_illinois_ssthresh,
-	.min_cwnd	= tcp_reno_min_cwnd,
 	.cong_avoid	= tcp_illinois_cong_avoid,
 	.set_state	= tcp_illinois_state,
 	.get_info	= tcp_illinois_info,
diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c
index 72f7218b0..e52ecb1f6 100644
--- a/net/ipv4/tcp_lp.c
+++ b/net/ipv4/tcp_lp.c
@@ -318,7 +318,6 @@ static struct tcp_congestion_ops tcp_lp __read_mostly = {
 	.init = tcp_lp_init,
 	.ssthresh = tcp_reno_ssthresh,
 	.cong_avoid = tcp_lp_cong_avoid,
-	.min_cwnd = tcp_reno_min_cwnd,
 	.pkts_acked = tcp_lp_pkts_acked,
 
 	.owner = THIS_MODULE,
diff --git a/net/ipv4/tcp_scalable.c b/net/ipv4/tcp_scalable.c
index e018e734a..cd50bbb41 100644
--- a/net/ipv4/tcp_scalable.c
+++ b/net/ipv4/tcp_scalable.c
@@ -38,7 +38,6 @@ static u32 tcp_scalable_ssthresh(struct sock *sk)
 static struct tcp_congestion_ops tcp_scalable __read_mostly = {
 	.ssthresh	= tcp_scalable_ssthresh,
 	.cong_avoid	= tcp_scalable_cong_avoid,
-	.min_cwnd	= tcp_reno_min_cwnd,
 
 	.owner		= THIS_MODULE,
 	.name		= "scalable",
diff --git a/net/ipv4/tcp_vegas.c b/net/ipv4/tcp_vegas.c
index c042e529a..0e4b6d2a4 100644
--- a/net/ipv4/tcp_vegas.c
+++ b/net/ipv4/tcp_vegas.c
@@ -310,7 +310,6 @@ static struct tcp_congestion_ops tcp_vegas __read_mostly = {
 	.init		= tcp_vegas_init,
 	.ssthresh	= tcp_reno_ssthresh,
 	.cong_avoid	= tcp_vegas_cong_avoid,
-	.min_cwnd	= tcp_reno_min_cwnd,
 	.pkts_acked	= tcp_vegas_pkts_acked,
 	.set_state	= tcp_vegas_state,
 	.cwnd_event	= tcp_vegas_cwnd_event,
diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c
index 3c9c80c04..81911a923 100644
--- a/net/ipv4/tcp_westwood.c
+++ b/net/ipv4/tcp_westwood.c
@@ -273,7 +273,6 @@ static struct tcp_congestion_ops tcp_westwood __read_mostly = {
 	.init		= tcp_westwood_init,
 	.ssthresh	= tcp_reno_ssthresh,
 	.cong_avoid	= tcp_reno_cong_avoid,
-	.min_cwnd	= tcp_westwood_bw_rttmin,
 	.cwnd_event	= tcp_westwood_event,
 	.get_info	= tcp_westwood_info,
 	.pkts_acked	= tcp_westwood_pkts_acked,
diff --git a/net/ipv4/tcp_yeah.c b/net/ipv4/tcp_yeah.c
index 80e9c70c0..e50c6df2c 100644
--- a/net/ipv4/tcp_yeah.c
+++ b/net/ipv4/tcp_yeah.c
@@ -227,7 +227,6 @@ static struct tcp_congestion_ops tcp_yeah __read_mostly = {
 	.init		= tcp_yeah_init,
 	.ssthresh	= tcp_yeah_ssthresh,
 	.cong_avoid	= tcp_yeah_cong_avoid,
-	.min_cwnd	= tcp_reno_min_cwnd,
 	.set_state	= tcp_vegas_state,
 	.cwnd_event	= tcp_vegas_cwnd_event,
 	.get_info	= tcp_vegas_get_info,