wifi: add tcp delay ack support [1/1]

PD#OTT-5388

Problem:
wifi rx throughput issue

Solution:
add tcp delay ack support
enable tcp dealy ack by following command:
echo 1 > /proc/sys/net/ipv4/tcp_use_userconfig
echo 60 > /proc/sys/net/ipv4/tcp_delack_seg

Verify:
u211

Change-Id: I060810b2800bae377388ba6ed9f9256597c9e6ea
Signed-off-by: libo <bo.li@amlogic.com>

5 files changed, 102 insertions, 9 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index e511825..370161d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -140,6 +140,8 @@ void tcp_time_wait(struct sock *sk, int state, int timeo);
 						 * most likely due to retrans in 3WHS.
 						 */
 
+#define TCP_DELACK_SEG 1 /*Number of full MSS to receive before Acking RFC2581*/
+
 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
 					                 * for local resources.
 					                 */
@@ -266,6 +268,11 @@ extern int sysctl_tcp_early_retrans;
 extern int sysctl_tcp_limit_output_bytes;
 extern int sysctl_tcp_challenge_ack_limit;
 extern int sysctl_tcp_min_tso_segs;
+
+/* sysctl variables for controlling various tcp parameters */
+extern int sysctl_tcp_delack_seg;
+extern int sysctl_tcp_use_userconfig;
+
 extern int sysctl_tcp_min_rtt_wlen;
 extern int sysctl_tcp_autocorking;
 extern int sysctl_tcp_invalid_ratelimit;
@@ -364,6 +371,11 @@ ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
 			struct pipe_inode_info *pipe, size_t len,
 			unsigned int flags);
 
+extern int tcp_use_userconfig_sysctl_handler(struct ctl_table *table, int write,
+	void __user *buffer, size_t *length, loff_t *ppos);
+extern int tcp_proc_delayed_ack_control(struct ctl_table *table, int write,
+	void __user *buffer, size_t *length, loff_t *ppos);
+
 static inline void tcp_dec_quickack_mode(struct sock *sk,
 					 const unsigned int pkts)
 {
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index d540bf1..a8d8b8d 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -42,6 +42,11 @@ static int tcp_syn_retries_max = MAX_TCP_SYNCNT;
 static int ip_ping_group_range_min[] = { 0, 0 };
 static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };
 
+static int tcp_delack_seg_min = TCP_DELACK_MIN;
+static int tcp_delack_seg_max = 60;
+static int tcp_use_userconfig_min;
+static int tcp_use_userconfig_max = 1;
+
 /* Update system visible IP port range */
 static void set_local_port_range(struct net *net, int range[2])
 {
@@ -684,6 +689,24 @@ static struct ctl_table ipv4_table[] = {
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= &one
 	},
+	{
+		.procname	= "tcp_delack_seg",
+		.data		= &sysctl_tcp_delack_seg,
+		.maxlen		= sizeof(sysctl_tcp_delack_seg),
+		.mode		= 0644,
+		.proc_handler   = tcp_proc_delayed_ack_control,
+		.extra1		= &tcp_delack_seg_min,
+		.extra2		= &tcp_delack_seg_max,
+	},
+	{
+		.procname	= "tcp_use_userconfig",
+		.data	        = &sysctl_tcp_use_userconfig,
+		.maxlen		= sizeof(sysctl_tcp_use_userconfig),
+		.mode		= 0644,
+		.proc_handler	= tcp_use_userconfig_sysctl_handler,
+		.extra1		= &tcp_use_userconfig_min,
+		.extra2		= &tcp_use_userconfig_max,
+	},
 	{ }
 };
 
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f0a2a86..3729137 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -297,6 +297,12 @@ EXPORT_SYMBOL(sysctl_tcp_mem);
 EXPORT_SYMBOL(sysctl_tcp_rmem);
 EXPORT_SYMBOL(sysctl_tcp_wmem);
 
+int sysctl_tcp_delack_seg __read_mostly = TCP_DELACK_SEG;
+EXPORT_SYMBOL(sysctl_tcp_delack_seg);
+
+int sysctl_tcp_use_userconfig __read_mostly;
+EXPORT_SYMBOL(sysctl_tcp_use_userconfig);
+
 atomic_long_t tcp_memory_allocated;	/* Current allocated memory. */
 EXPORT_SYMBOL(tcp_memory_allocated);
 
@@ -1463,8 +1469,12 @@ static void tcp_cleanup_rbuf(struct sock *sk, int copied)
 		   /* Delayed ACKs frequently hit locked sockets during bulk
 		    * receive. */
 		if (icsk->icsk_ack.blocked ||
-		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
-		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
+			/* Once-per-sysctl_tcp_delack_seg segments
+			 * ACK was not sent by tcp_input.c
+			 */
+			tp->rcv_nxt - tp->rcv_wup > (icsk->icsk_ack.rcv_mss) *
+				sysctl_tcp_delack_seg ||
+
 		    /*
 		     * If this read emptied read buffer, we send ACK, if
 		     * connection is not bidirectional, user drained
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 17d88e4..f384e0c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5130,8 +5130,10 @@ static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
-	    /* More than one full frame received... */
-	if (((tp->rcv_nxt - tp->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss &&
+	/* More than one full frame received... */
+	if (((tp->rcv_nxt - tp->rcv_wup) >
+			(inet_csk(sk)->icsk_ack.rcv_mss) *
+				sysctl_tcp_delack_seg &&
 	     /* ... and right edge of window advances far enough.
 	      * (tcp_recvmsg() will send ACK otherwise). Or...
 	      */
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 6952338..84383ad 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -24,6 +24,57 @@
 
 int sysctl_tcp_thin_linear_timeouts __read_mostly;
 
+static void tcp_write_timer(unsigned long);
+static void tcp_delack_timer(unsigned long);
+static void tcp_keepalive_timer(unsigned long data);
+
+/*Function to reset tcp_ack related sysctl on resetting master control */
+void set_tcp_default(void)
+{
+	sysctl_tcp_delack_seg = TCP_DELACK_SEG;
+}
+
+/*sysctl handler for tcp_ack realted master control */
+int tcp_proc_delayed_ack_control(
+	struct ctl_table *table,
+	int write,
+	void __user *buffer,
+	size_t *length,
+	loff_t *ppos)
+{
+	int ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
+
+	/* The ret value will be 0 if the input validation is successful
+	 * and the values are written to sysctl table. If not, the stack
+	 * will continue to work with currently configured values
+	 */
+	return ret;
+}
+
+/*sysctl handler for tcp_ack realted master control */
+int tcp_use_userconfig_sysctl_handler(
+	struct ctl_table *table,
+	int write,
+	void __user *buffer,
+	size_t *length,
+	loff_t *ppos)
+{
+	int ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
+
+	if (write && ret == 0) {
+		if (!sysctl_tcp_use_userconfig)
+			set_tcp_default();
+	}
+	return ret;
+}
+
+void tcp_init_xmit_timers(struct sock *sk)
+{
+	inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer,
+				  &tcp_keepalive_timer);
+}
+EXPORT_SYMBOL(tcp_init_xmit_timers);
+
 /**
  *  tcp_write_err() - close socket and save error info
  *  @sk:  The socket the error has appeared on.
@@ -722,8 +773,3 @@ out:
 	sock_put(sk);
 }
 
-void tcp_init_xmit_timers(struct sock *sk)
-{
-	inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer,
-				  &tcp_keepalive_timer);
-}