Commit a594920f authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller
Browse files

inet: Remove an unnecessary argument of syn_ack_recalc(). 



Commit 0c3d79bc ("tcp: reduce SYN-ACK
retrans for TCP_DEFER_ACCEPT") introduces syn_ack_recalc() which decides
if a minisock is held and a SYN+ACK is retransmitted or not.

If rskq_defer_accept is not zero in syn_ack_recalc(), max_retries always
has the same value because max_retries is overwritten by rskq_defer_accept
in reqsk_timer_handler().

This commit adds three changes:
- remove redundant non-zero check for rskq_defer_accept in
   reqsk_timer_handler().
- remove max_retries from the arguments of syn_ack_recalc() and use
   rskq_defer_accept instead.
- rename thresh to max_syn_ack_retries for readability.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.co.jp>
Reviewed-by: default avatarBenjamin Herrenschmidt <benh@amazon.com>
CC: Julian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ac4cd478

net/ipv4/inet_connection_sock.c

+13 −20
Original line number Diff line number Diff line
@@ -648,20 +648,19 @@ no_route: 
EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);



/* Decide when to expire the request and when to resend SYN-ACK */

static inline void syn_ack_recalc(struct request_sock *req, const int thresh,

				  const int max_retries,

static void syn_ack_recalc(struct request_sock *req,

			   const int max_syn_ack_retries,

			   const u8 rskq_defer_accept,

			   int *expire, int *resend)

{

	if (!rskq_defer_accept) {

		*expire = req->num_timeout >= thresh;

		*expire = req->num_timeout >= max_syn_ack_retries;

		*resend = 1;

		return;

	}

	*expire = req->num_timeout >= thresh &&

		  (!inet_rsk(req)->acked || req->num_timeout >= max_retries);

	/*

	 * Do not resend while waiting for data after ACK,

	*expire = req->num_timeout >= max_syn_ack_retries &&

		  (!inet_rsk(req)->acked || req->num_timeout >= rskq_defer_accept);

	/* Do not resend while waiting for data after ACK,

	 * start to resend on end of deferring period to give

	 * last chance for data or ACK to create established socket.

	 */
@@ -720,15 +719,12 @@ static void reqsk_timer_handler(struct timer_list *t) 
	struct net *net = sock_net(sk_listener);

	struct inet_connection_sock *icsk = inet_csk(sk_listener);

	struct request_sock_queue *queue = &icsk->icsk_accept_queue;

	int qlen, expire = 0, resend = 0;

	int max_retries, thresh;

	u8 defer_accept;

	int max_syn_ack_retries, qlen, expire = 0, resend = 0;



	if (inet_sk_state_load(sk_listener) != TCP_LISTEN)

		goto drop;



	max_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;

	thresh = max_retries;

	max_syn_ack_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;

	/* Normally all the openreqs are young and become mature

	 * (i.e. converted to established socket) for first timeout.

	 * If synack was not acknowledged for 1 second, it means
@@ -750,17 +746,14 @@ static void reqsk_timer_handler(struct timer_list *t) 
	if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {

		int young = reqsk_queue_len_young(queue) << 1;



		while (thresh > 2) {

		while (max_syn_ack_retries > 2) {

			if (qlen < young)

				break;

			thresh--;

			max_syn_ack_retries--;

			young <<= 1;

		}

	}

	defer_accept = READ_ONCE(queue->rskq_defer_accept);

	if (defer_accept)

		max_retries = defer_accept;

	syn_ack_recalc(req, thresh, max_retries, defer_accept,

	syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept),

		       &expire, &resend);

	req->rsk_ops->syn_ack_timeout(req);

	if (!expire &&

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