Commit a762a980 authored by David S. Miller's avatar David S. Miller
Browse files

[TCP]: Kill extra cwnd validate in __tcp_push_pending_frames(). 



The tcp_cwnd_validate() function should only be invoked
if we actually send some frames, yet __tcp_push_pending_frames()
will always invoke it.  tcp_write_xmit() does the call for us,
so the call here can simply be removed.

Also, tcp_write_xmit() can be marked static.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f44b5271

include/net/tcp.h

+3 −23
Original line number Diff line number Diff line
@@ -848,7 +848,6 @@ extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 


/* tcp_output.c */



extern int tcp_write_xmit(struct sock *, int nonagle);

extern void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb);

extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,

				      unsigned cur_mss, int nonagle);
@@ -868,6 +867,9 @@ extern void tcp_push_one(struct sock *, unsigned mss_now); 
extern void tcp_send_ack(struct sock *sk);

extern void tcp_send_delayed_ack(struct sock *sk);



/* tcp_input.c */

extern void tcp_cwnd_application_limited(struct sock *sk);



/* tcp_timer.c */

extern void tcp_init_xmit_timers(struct sock *);

extern void tcp_clear_xmit_timers(struct sock *);
@@ -1234,28 +1236,6 @@ static inline void tcp_sync_left_out(struct tcp_sock *tp) 
	tp->left_out = tp->sacked_out + tp->lost_out;

}



extern void tcp_cwnd_application_limited(struct sock *sk);



/* Congestion window validation. (RFC2861) */



static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp)

{

	__u32 packets_out = tp->packets_out;



	if (packets_out >= tp->snd_cwnd) {

		/* Network is feed fully. */

		tp->snd_cwnd_used = 0;

		tp->snd_cwnd_stamp = tcp_time_stamp;

	} else {

		/* Network starves. */

		if (tp->packets_out > tp->snd_cwnd_used)

			tp->snd_cwnd_used = tp->packets_out;



		if ((s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= tp->rto)

			tcp_cwnd_application_limited(sk);

	}

}



/* Set slow start threshould and cwnd not falling to slow start */

static inline void __tcp_enter_cwr(struct tcp_sock *tp)

{

net/ipv4/tcp_output.c

+49 −30
Original line number Diff line number Diff line
@@ -511,35 +511,6 @@ static inline int tcp_skb_is_last(const struct sock *sk, 
	return skb->next == (struct sk_buff *)&sk->sk_write_queue;

}



/* Push out any pending frames which were held back due to

 * TCP_CORK or attempt at coalescing tiny packets.

 * The socket must be locked by the caller.

 */

void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,

			       unsigned cur_mss, int nonagle)

{

	struct sk_buff *skb = sk->sk_send_head;



	if (skb) {

		if (!tcp_skb_is_last(sk, skb))

			nonagle = TCP_NAGLE_PUSH;

		if (!tcp_snd_test(sk, skb, cur_mss, nonagle) ||

		    tcp_write_xmit(sk, nonagle))

			tcp_check_probe_timer(sk, tp);

	}

	tcp_cwnd_validate(sk, tp);

}



void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb)

{

	struct tcp_sock *tp = tcp_sk(sk);



	if (after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd) ||

	    tcp_packets_in_flight(tp) >= tp->snd_cwnd ||

	    tcp_write_xmit(sk, tp->nonagle))

		tcp_check_probe_timer(sk, tp);

}



int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp)

{

	struct sk_buff *skb = sk->sk_send_head;
@@ -841,6 +812,26 @@ unsigned int tcp_current_mss(struct sock *sk, int large) 
	return mss_now;

}



/* Congestion window validation. (RFC2861) */



static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp)

{

	__u32 packets_out = tp->packets_out;



	if (packets_out >= tp->snd_cwnd) {

		/* Network is feed fully. */

		tp->snd_cwnd_used = 0;

		tp->snd_cwnd_stamp = tcp_time_stamp;

	} else {

		/* Network starves. */

		if (tp->packets_out > tp->snd_cwnd_used)

			tp->snd_cwnd_used = tp->packets_out;



		if ((s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= tp->rto)

			tcp_cwnd_application_limited(sk);

	}

}



/* This routine writes packets to the network.  It advances the

 * send_head.  This happens as incoming acks open up the remote

 * window for us.
@@ -848,7 +839,7 @@ unsigned int tcp_current_mss(struct sock *sk, int large) 
 * Returns 1, if no segments are in flight and we have queued segments, but

 * cannot send anything now because of SWS or another problem.

 */

int tcp_write_xmit(struct sock *sk, int nonagle)

static int tcp_write_xmit(struct sock *sk, int nonagle)

{

	struct tcp_sock *tp = tcp_sk(sk);

	unsigned int mss_now;
@@ -901,6 +892,34 @@ int tcp_write_xmit(struct sock *sk, int nonagle) 
	return 0;

}



/* Push out any pending frames which were held back due to

 * TCP_CORK or attempt at coalescing tiny packets.

 * The socket must be locked by the caller.

 */

void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,

			       unsigned cur_mss, int nonagle)

{

	struct sk_buff *skb = sk->sk_send_head;



	if (skb) {

		if (!tcp_skb_is_last(sk, skb))

			nonagle = TCP_NAGLE_PUSH;

		if (!tcp_snd_test(sk, skb, cur_mss, nonagle) ||

		    tcp_write_xmit(sk, nonagle))

			tcp_check_probe_timer(sk, tp);

	}

}



void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb)

{

	struct tcp_sock *tp = tcp_sk(sk);



	if (after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd) ||

	    tcp_packets_in_flight(tp) >= tp->snd_cwnd ||

	    tcp_write_xmit(sk, tp->nonagle))

		tcp_check_probe_timer(sk, tp);

}



/* This function returns the amount that we can raise the

 * usable window based on the following constraints

 *

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