[linux-2.6-block.git] / net / rxrpc / call_event.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/circ_buf.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/udp.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"

/*
 * Propose a PING ACK be sent.
 */
static void rxrpc_propose_ping(struct rxrpc_call *call,
			       bool immediate, bool background)
{
	if (immediate) {
		if (background &&
		    !test_and_set_bit(RXRPC_CALL_EV_PING, &call->events))
			rxrpc_queue_call(call);
	} else {
		unsigned long now = jiffies;
		unsigned long ping_at = now + rxrpc_idle_ack_delay;

		if (time_before(ping_at, call->ping_at)) {
			WRITE_ONCE(call->ping_at, ping_at);
			rxrpc_reduce_call_timer(call, ping_at, now,
						rxrpc_timer_set_for_ping);
		}
	}
}

/*
 * propose an ACK be sent
 */
static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
				u32 serial, bool immediate, bool background,
				enum rxrpc_propose_ack_trace why)
{
	enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
	unsigned long expiry = rxrpc_soft_ack_delay;
	s8 prior = rxrpc_ack_priority[ack_reason];

	/* Pings are handled specially because we don't want to accidentally
	 * lose a ping response by subsuming it into a ping.
	 */
	if (ack_reason == RXRPC_ACK_PING) {
		rxrpc_propose_ping(call, immediate, background);
		goto trace;
	}

	/* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
	 * numbers, but we don't alter the timeout.
	 */
	_debug("prior %u %u vs %u %u",
	       ack_reason, prior,
	       call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
	if (ack_reason == call->ackr_reason) {
		if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
			outcome = rxrpc_propose_ack_update;
			call->ackr_serial = serial;
		}
		if (!immediate)
			goto trace;
	} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
		call->ackr_reason = ack_reason;
		call->ackr_serial = serial;
	} else {
		outcome = rxrpc_propose_ack_subsume;
	}

	switch (ack_reason) {
	case RXRPC_ACK_REQUESTED:
		if (rxrpc_requested_ack_delay < expiry)
			expiry = rxrpc_requested_ack_delay;
		if (serial == 1)
			immediate = false;
		break;

	case RXRPC_ACK_DELAY:
		if (rxrpc_soft_ack_delay < expiry)
			expiry = rxrpc_soft_ack_delay;
		break;

	case RXRPC_ACK_IDLE:
		if (rxrpc_idle_ack_delay < expiry)
			expiry = rxrpc_idle_ack_delay;
		break;

	default:
		immediate = true;
		break;
	}

	if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
		_debug("already scheduled");
	} else if (immediate || expiry == 0) {
		_debug("immediate ACK %lx", call->events);
		if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
		    background)
			rxrpc_queue_call(call);
	} else {
		unsigned long now = jiffies, ack_at;

		if (call->peer->rtt_usage > 0)
			ack_at = nsecs_to_jiffies(call->peer->rtt);
		else
			ack_at = expiry;

		ack_at += READ_ONCE(call->tx_backoff);
		ack_at += now;
		if (time_before(ack_at, call->ack_at)) {
			WRITE_ONCE(call->ack_at, ack_at);
			rxrpc_reduce_call_timer(call, ack_at, now,
						rxrpc_timer_set_for_ack);
		}
	}

trace:
	trace_rxrpc_propose_ack(call, why, ack_reason, serial, immediate,
				background, outcome);
}

/*
 * propose an ACK be sent, locking the call structure
 */
void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
		       u32 serial, bool immediate, bool background,
		       enum rxrpc_propose_ack_trace why)
{
	spin_lock_bh(&call->lock);
	__rxrpc_propose_ACK(call, ack_reason, serial,
			    immediate, background, why);
	spin_unlock_bh(&call->lock);
}

/*
 * Handle congestion being detected by the retransmit timeout.
 */
static void rxrpc_congestion_timeout(struct rxrpc_call *call)
{
	set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
}

/*
 * Perform retransmission of NAK'd and unack'd packets.
 */
static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j)
{
	struct sk_buff *skb;
	unsigned long resend_at;
	rxrpc_seq_t cursor, seq, top;
	ktime_t now, max_age, oldest, ack_ts, timeout, min_timeo;
	int ix;
	u8 annotation, anno_type, retrans = 0, unacked = 0;

	_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);

	if (call->peer->rtt_usage > 1)
		timeout = ns_to_ktime(call->peer->rtt * 3 / 2);
	else
		timeout = ms_to_ktime(rxrpc_resend_timeout);
	min_timeo = ns_to_ktime((1000000000 / HZ) * 4);
	if (ktime_before(timeout, min_timeo))
		timeout = min_timeo;

	now = ktime_get_real();
	max_age = ktime_sub(now, timeout);

	spin_lock_bh(&call->lock);

	cursor = call->tx_hard_ack;
	top = call->tx_top;
	ASSERT(before_eq(cursor, top));
	if (cursor == top)
		goto out_unlock;

	/* Scan the packet list without dropping the lock and decide which of
	 * the packets in the Tx buffer we're going to resend and what the new
	 * resend timeout will be.
	 */
	trace_rxrpc_resend(call, (cursor + 1) & RXRPC_RXTX_BUFF_MASK);
	oldest = now;
	for (seq = cursor + 1; before_eq(seq, top); seq++) {
		ix = seq & RXRPC_RXTX_BUFF_MASK;
		annotation = call->rxtx_annotations[ix];
		anno_type = annotation & RXRPC_TX_ANNO_MASK;
		annotation &= ~RXRPC_TX_ANNO_MASK;
		if (anno_type == RXRPC_TX_ANNO_ACK)
			continue;

		skb = call->rxtx_buffer[ix];
		rxrpc_see_skb(skb, rxrpc_skb_seen);

		if (anno_type == RXRPC_TX_ANNO_UNACK) {
			if (ktime_after(skb->tstamp, max_age)) {
				if (ktime_before(skb->tstamp, oldest))
					oldest = skb->tstamp;
				continue;
			}
			if (!(annotation & RXRPC_TX_ANNO_RESENT))
				unacked++;
		}

		/* Okay, we need to retransmit a packet. */
		call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS | annotation;
		retrans++;
		trace_rxrpc_retransmit(call, seq, annotation | anno_type,
				       ktime_to_ns(ktime_sub(skb->tstamp, max_age)));
	}

	resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
	resend_at += jiffies + rxrpc_resend_timeout;
	WRITE_ONCE(call->resend_at, resend_at);

	if (unacked)
		rxrpc_congestion_timeout(call);

	/* If there was nothing that needed retransmission then it's likely
	 * that an ACK got lost somewhere.  Send a ping to find out instead of
	 * retransmitting data.
	 */
	if (!retrans) {
		rxrpc_reduce_call_timer(call, resend_at, now_j,
					rxrpc_timer_set_for_resend);
		spin_unlock_bh(&call->lock);
		ack_ts = ktime_sub(now, call->acks_latest_ts);
		if (ktime_to_ns(ack_ts) < call->peer->rtt)
			goto out;
		rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, false,
				  rxrpc_propose_ack_ping_for_lost_ack);
		rxrpc_send_ack_packet(call, true, NULL);
		goto out;
	}

	/* Now go through the Tx window and perform the retransmissions.  We
	 * have to drop the lock for each send.  If an ACK comes in whilst the
	 * lock is dropped, it may clear some of the retransmission markers for
	 * packets that it soft-ACKs.
	 */
	for (seq = cursor + 1; before_eq(seq, top); seq++) {
		ix = seq & RXRPC_RXTX_BUFF_MASK;
		annotation = call->rxtx_annotations[ix];
		anno_type = annotation & RXRPC_TX_ANNO_MASK;
		if (anno_type != RXRPC_TX_ANNO_RETRANS)
			continue;

		skb = call->rxtx_buffer[ix];
		rxrpc_get_skb(skb, rxrpc_skb_got);
		spin_unlock_bh(&call->lock);

		if (rxrpc_send_data_packet(call, skb, true) < 0) {
			rxrpc_free_skb(skb, rxrpc_skb_freed);
			return;
		}

		if (rxrpc_is_client_call(call))
			rxrpc_expose_client_call(call);

		rxrpc_free_skb(skb, rxrpc_skb_freed);
		spin_lock_bh(&call->lock);

		/* We need to clear the retransmit state, but there are two
		 * things we need to be aware of: A new ACK/NAK might have been
		 * received and the packet might have been hard-ACK'd (in which
		 * case it will no longer be in the buffer).
		 */
		if (after(seq, call->tx_hard_ack)) {
			annotation = call->rxtx_annotations[ix];
			anno_type = annotation & RXRPC_TX_ANNO_MASK;
			if (anno_type == RXRPC_TX_ANNO_RETRANS ||
			    anno_type == RXRPC_TX_ANNO_NAK) {
				annotation &= ~RXRPC_TX_ANNO_MASK;
				annotation |= RXRPC_TX_ANNO_UNACK;
			}
			annotation |= RXRPC_TX_ANNO_RESENT;
			call->rxtx_annotations[ix] = annotation;
		}

		if (after(call->tx_hard_ack, seq))
			seq = call->tx_hard_ack;
	}

out_unlock:
	spin_unlock_bh(&call->lock);
out:
	_leave("");
}

/*
 * Handle retransmission and deferred ACK/abort generation.
 */
void rxrpc_process_call(struct work_struct *work)
{
	struct rxrpc_call *call =
		container_of(work, struct rxrpc_call, processor);
	rxrpc_serial_t *send_ack;
	unsigned long now, next, t;
	unsigned int iterations = 0;

	rxrpc_see_call(call);

	//printk("\n--------------------\n");
	_enter("{%d,%s,%lx}",
	       call->debug_id, rxrpc_call_states[call->state], call->events);

recheck_state:
	/* Limit the number of times we do this before returning to the manager */
	iterations++;
	if (iterations > 5)
		goto requeue;

	if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
		rxrpc_send_abort_packet(call);
		goto recheck_state;
	}

	if (call->state == RXRPC_CALL_COMPLETE) {
		del_timer_sync(&call->timer);
		rxrpc_notify_socket(call);
		goto out_put;
	}

	/* Work out if any timeouts tripped */
	now = jiffies;
	t = READ_ONCE(call->expect_rx_by);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
		set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	}

	t = READ_ONCE(call->expect_req_by);
	if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST &&
	    time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
		set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	}

	t = READ_ONCE(call->expect_term_by);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_hard, now);
		set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	}

	t = READ_ONCE(call->ack_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
		cmpxchg(&call->ack_at, t, now + MAX_JIFFY_OFFSET);
		set_bit(RXRPC_CALL_EV_ACK, &call->events);
	}

	t = READ_ONCE(call->ack_lost_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_lost_ack, now);
		cmpxchg(&call->ack_lost_at, t, now + MAX_JIFFY_OFFSET);
		set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
	}

	t = READ_ONCE(call->keepalive_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
		cmpxchg(&call->keepalive_at, t, now + MAX_JIFFY_OFFSET);
		rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, true,
				  rxrpc_propose_ack_ping_for_keepalive);
		set_bit(RXRPC_CALL_EV_PING, &call->events);
	}

	t = READ_ONCE(call->ping_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
		cmpxchg(&call->ping_at, t, now + MAX_JIFFY_OFFSET);
		set_bit(RXRPC_CALL_EV_PING, &call->events);
	}

	t = READ_ONCE(call->resend_at);
	if (time_after_eq(now, t)) {
		trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
		cmpxchg(&call->resend_at, t, now + MAX_JIFFY_OFFSET);
		set_bit(RXRPC_CALL_EV_RESEND, &call->events);
	}

	/* Process events */
	if (test_and_clear_bit(RXRPC_CALL_EV_EXPIRED, &call->events)) {
		if (test_bit(RXRPC_CALL_RX_HEARD, &call->flags) &&
		    (int)call->conn->hi_serial - (int)call->rx_serial > 0) {
			trace_rxrpc_call_reset(call);
			rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ECONNRESET);
		} else {
			rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ETIME);
		}
		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
		goto recheck_state;
	}

	send_ack = NULL;
	if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events)) {
		call->acks_lost_top = call->tx_top;
		rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, false,
				  rxrpc_propose_ack_ping_for_lost_ack);
		send_ack = &call->acks_lost_ping;
	}

	if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) ||
	    send_ack) {
		if (call->ackr_reason) {
			rxrpc_send_ack_packet(call, false, send_ack);
			goto recheck_state;
		}
	}

	if (test_and_clear_bit(RXRPC_CALL_EV_PING, &call->events)) {
		rxrpc_send_ack_packet(call, true, NULL);
		goto recheck_state;
	}

	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events)) {
		rxrpc_resend(call, now);
		goto recheck_state;
	}

	/* Make sure the timer is restarted */
	next = call->expect_rx_by;

#define set(T) { t = READ_ONCE(T); if (time_before(t, next)) next = t; }

	set(call->expect_req_by);
	set(call->expect_term_by);
	set(call->ack_at);
	set(call->ack_lost_at);
	set(call->resend_at);
	set(call->keepalive_at);
	set(call->ping_at);

	now = jiffies;
	if (time_after_eq(now, next))
		goto recheck_state;

	rxrpc_reduce_call_timer(call, next, now, rxrpc_timer_restart);

	/* other events may have been raised since we started checking */
	if (call->events && call->state < RXRPC_CALL_COMPLETE)
		goto requeue;

out_put:
	rxrpc_put_call(call, rxrpc_call_put);
out:
	_leave("");
	return;

requeue:
	__rxrpc_queue_call(call);
	goto out;
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
17926a79 DH	2	/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
	3	*
	4	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
17926a79 DH	6	*/
17926a79 DH	7
9b6d5398 JP	8	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9b6d5398 JP	9
17926a79 DH	10	#include <linux/module.h>
	11	#include <linux/circ_buf.h>
	12	#include <linux/net.h>
	13	#include <linux/skbuff.h>
5a0e3ad6	14	#include <linux/slab.h>
17926a79 DH	15	#include <linux/udp.h>
	16	#include <net/sock.h>
	17	#include <net/af_rxrpc.h>
	18	#include "ar-internal.h"
	19
a5af7e1f DH	20	/*
	21	* Propose a PING ACK be sent.
	22	*/
	23	static void rxrpc_propose_ping(struct rxrpc_call *call,
	24	bool immediate, bool background)
	25	{
	26	if (immediate) {
	27	if (background &&
	28	!test_and_set_bit(RXRPC_CALL_EV_PING, &call->events))
	29	rxrpc_queue_call(call);
	30	} else {
a158bdd3 DH	31	unsigned long now = jiffies;
a158bdd3 DH	32	unsigned long ping_at = now + rxrpc_idle_ack_delay;
a5af7e1f	33
a158bdd3 DH	34	if (time_before(ping_at, call->ping_at)) {
	35	WRITE_ONCE(call->ping_at, ping_at);
	36	rxrpc_reduce_call_timer(call, ping_at, now,
	37	rxrpc_timer_set_for_ping);
a5af7e1f DH	38	}
	39	}
	40	}
	41
17926a79	42	/*
248f219c	43	* propose an ACK be sent
17926a79	44	*/
248f219c	45	static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
e8c3af6b	46	u32 serial, bool immediate, bool background,
9c7ad434	47	enum rxrpc_propose_ack_trace why)
17926a79	48	{
9c7ad434	49	enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
beb8e5e4	50	unsigned long expiry = rxrpc_soft_ack_delay;
17926a79 DH	51	s8 prior = rxrpc_ack_priority[ack_reason];
17926a79 DH	52
a5af7e1f DH	53	/* Pings are handled specially because we don't want to accidentally
	54	* lose a ping response by subsuming it into a ping.
	55	*/
	56	if (ack_reason == RXRPC_ACK_PING) {
	57	rxrpc_propose_ping(call, immediate, background);
	58	goto trace;
	59	}
	60
248f219c DH	61	/* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
	62	* numbers, but we don't alter the timeout.
	63	*/
	64	_debug("prior %u %u vs %u %u",
	65	ack_reason, prior,
	66	call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
	67	if (ack_reason == call->ackr_reason) {
	68	if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
9c7ad434	69	outcome = rxrpc_propose_ack_update;
248f219c	70	call->ackr_serial = serial;
17926a79	71	}
248f219c	72	if (!immediate)
9c7ad434	73	goto trace;
248f219c DH	74	} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
	75	call->ackr_reason = ack_reason;
	76	call->ackr_serial = serial;
9c7ad434 DH	77	} else {
9c7ad434 DH	78	outcome = rxrpc_propose_ack_subsume;
17926a79 DH	79	}
17926a79 DH	80
248f219c DH	81	switch (ack_reason) {
	82	case RXRPC_ACK_REQUESTED:
	83	if (rxrpc_requested_ack_delay < expiry)
	84	expiry = rxrpc_requested_ack_delay;
	85	if (serial == 1)
	86	immediate = false;
	87	break;
17926a79	88
248f219c DH	89	case RXRPC_ACK_DELAY:
	90	if (rxrpc_soft_ack_delay < expiry)
	91	expiry = rxrpc_soft_ack_delay;
	92	break;
17926a79	93
248f219c	94	case RXRPC_ACK_IDLE:
91c2c7b6	95	if (rxrpc_idle_ack_delay < expiry)
248f219c DH	96	expiry = rxrpc_idle_ack_delay;
248f219c DH	97	break;
17926a79	98
248f219c DH	99	default:
	100	immediate = true;
	101	break;
17926a79 DH	102	}
17926a79 DH	103
248f219c DH	104	if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
	105	_debug("already scheduled");
	106	} else if (immediate \|\| expiry == 0) {
	107	_debug("immediate ACK %lx", call->events);
	108	if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
	109	background)
	110	rxrpc_queue_call(call);
	111	} else {
beb8e5e4 DH	112	unsigned long now = jiffies, ack_at;
	113
	114	if (call->peer->rtt_usage > 0)
	115	ack_at = nsecs_to_jiffies(call->peer->rtt);
	116	else
	117	ack_at = expiry;
	118
c7e86acf	119	ack_at += READ_ONCE(call->tx_backoff);
282ef472	120	ack_at += now;
a158bdd3 DH	121	if (time_before(ack_at, call->ack_at)) {
	122	WRITE_ONCE(call->ack_at, ack_at);
	123	rxrpc_reduce_call_timer(call, ack_at, now,
	124	rxrpc_timer_set_for_ack);
17926a79 DH	125	}
17926a79 DH	126	}
9c7ad434 DH	127
	128	trace:
	129	trace_rxrpc_propose_ack(call, why, ack_reason, serial, immediate,
	130	background, outcome);
17926a79 DH	131	}
	132
	133	/*
248f219c	134	* propose an ACK be sent, locking the call structure
17926a79	135	*/
248f219c	136	void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
e8c3af6b	137	u32 serial, bool immediate, bool background,
9c7ad434	138	enum rxrpc_propose_ack_trace why)
17926a79	139	{
248f219c	140	spin_lock_bh(&call->lock);
e8c3af6b	141	__rxrpc_propose_ACK(call, ack_reason, serial,
9c7ad434	142	immediate, background, why);
248f219c	143	spin_unlock_bh(&call->lock);
17926a79 DH	144	}
17926a79 DH	145
57494343 DH	146	/*
	147	* Handle congestion being detected by the retransmit timeout.
	148	*/
	149	static void rxrpc_congestion_timeout(struct rxrpc_call *call)
	150	{
	151	set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
	152	}
	153
17926a79	154	/*
248f219c	155	* Perform retransmission of NAK'd and unack'd packets.
17926a79	156	*/
a158bdd3	157	static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j)
17926a79	158	{
17926a79	159	struct sk_buff *skb;
a158bdd3	160	unsigned long resend_at;
248f219c	161	rxrpc_seq_t cursor, seq, top;
beb8e5e4	162	ktime_t now, max_age, oldest, ack_ts, timeout, min_timeo;
248f219c	163	int ix;
57494343	164	u8 annotation, anno_type, retrans = 0, unacked = 0;
17926a79	165
248f219c	166	_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
17926a79	167
beb8e5e4 DH	168	if (call->peer->rtt_usage > 1)
	169	timeout = ns_to_ktime(call->peer->rtt * 3 / 2);
	170	else
	171	timeout = ms_to_ktime(rxrpc_resend_timeout);
	172	min_timeo = ns_to_ktime((1000000000 / HZ) * 4);
	173	if (ktime_before(timeout, min_timeo))
	174	timeout = min_timeo;
	175
a158bdd3	176	now = ktime_get_real();
beb8e5e4	177	max_age = ktime_sub(now, timeout);
50235c4b	178
17926a79 DH	179	spin_lock_bh(&call->lock);
17926a79 DH	180
248f219c DH	181	cursor = call->tx_hard_ack;
	182	top = call->tx_top;
	183	ASSERT(before_eq(cursor, top));
	184	if (cursor == top)
	185	goto out_unlock;
	186
	187	/* Scan the packet list without dropping the lock and decide which of
	188	* the packets in the Tx buffer we're going to resend and what the new
	189	* resend timeout will be.
	190	*/
827efed6	191	trace_rxrpc_resend(call, (cursor + 1) & RXRPC_RXTX_BUFF_MASK);
50235c4b	192	oldest = now;
dfa7d920	193	for (seq = cursor + 1; before_eq(seq, top); seq++) {
248f219c DH	194	ix = seq & RXRPC_RXTX_BUFF_MASK;
248f219c DH	195	annotation = call->rxtx_annotations[ix];
f07373ea DH	196	anno_type = annotation & RXRPC_TX_ANNO_MASK;
	197	annotation &= ~RXRPC_TX_ANNO_MASK;
	198	if (anno_type == RXRPC_TX_ANNO_ACK)
248f219c	199	continue;
17926a79	200
248f219c	201	skb = call->rxtx_buffer[ix];
987db9f7	202	rxrpc_see_skb(skb, rxrpc_skb_seen);
17926a79	203
f07373ea	204	if (anno_type == RXRPC_TX_ANNO_UNACK) {
50235c4b DH	205	if (ktime_after(skb->tstamp, max_age)) {
	206	if (ktime_before(skb->tstamp, oldest))
	207	oldest = skb->tstamp;
248f219c	208	continue;
33c40e24	209	}
57494343 DH	210	if (!(annotation & RXRPC_TX_ANNO_RESENT))
57494343 DH	211	unacked++;
17926a79	212	}
17926a79	213
248f219c	214	/* Okay, we need to retransmit a packet. */
f07373ea	215	call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS \| annotation;
57494343	216	retrans++;
c6672e3f DH	217	trace_rxrpc_retransmit(call, seq, annotation \| anno_type,
c6672e3f DH	218	ktime_to_ns(ktime_sub(skb->tstamp, max_age)));
dfa7d920	219	}
248f219c	220
59299aa1	221	resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
a158bdd3 DH	222	resend_at += jiffies + rxrpc_resend_timeout;
a158bdd3 DH	223	WRITE_ONCE(call->resend_at, resend_at);
248f219c	224
57494343 DH	225	if (unacked)
	226	rxrpc_congestion_timeout(call);
	227
	228	/* If there was nothing that needed retransmission then it's likely
	229	* that an ACK got lost somewhere. Send a ping to find out instead of
	230	* retransmitting data.
	231	*/
	232	if (!retrans) {
f82eb88b	233	rxrpc_reduce_call_timer(call, resend_at, now_j,
a158bdd3	234	rxrpc_timer_set_for_resend);
57494343 DH	235	spin_unlock_bh(&call->lock);
	236	ack_ts = ktime_sub(now, call->acks_latest_ts);
	237	if (ktime_to_ns(ack_ts) < call->peer->rtt)
	238	goto out;
e8c3af6b	239	rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, false,
57494343	240	rxrpc_propose_ack_ping_for_lost_ack);
bd1fdf8c	241	rxrpc_send_ack_packet(call, true, NULL);
57494343 DH	242	goto out;
	243	}
	244
248f219c DH	245	/* Now go through the Tx window and perform the retransmissions. We
	246	* have to drop the lock for each send. If an ACK comes in whilst the
	247	* lock is dropped, it may clear some of the retransmission markers for
	248	* packets that it soft-ACKs.
	249	*/
dfa7d920	250	for (seq = cursor + 1; before_eq(seq, top); seq++) {
248f219c DH	251	ix = seq & RXRPC_RXTX_BUFF_MASK;
248f219c DH	252	annotation = call->rxtx_annotations[ix];
f07373ea DH	253	anno_type = annotation & RXRPC_TX_ANNO_MASK;
f07373ea DH	254	if (anno_type != RXRPC_TX_ANNO_RETRANS)
248f219c	255	continue;
17926a79	256
248f219c	257	skb = call->rxtx_buffer[ix];
987db9f7	258	rxrpc_get_skb(skb, rxrpc_skb_got);
17926a79	259	spin_unlock_bh(&call->lock);
17926a79	260
a1767077	261	if (rxrpc_send_data_packet(call, skb, true) < 0) {
987db9f7	262	rxrpc_free_skb(skb, rxrpc_skb_freed);
248f219c DH	263	return;
248f219c DH	264	}
17926a79	265
248f219c DH	266	if (rxrpc_is_client_call(call))
248f219c DH	267	rxrpc_expose_client_call(call);
17926a79	268
987db9f7	269	rxrpc_free_skb(skb, rxrpc_skb_freed);
17926a79	270	spin_lock_bh(&call->lock);
17926a79	271
248f219c DH	272	/* We need to clear the retransmit state, but there are two
	273	* things we need to be aware of: A new ACK/NAK might have been
	274	* received and the packet might have been hard-ACK'd (in which
	275	* case it will no longer be in the buffer).
	276	*/
f07373ea DH	277	if (after(seq, call->tx_hard_ack)) {
	278	annotation = call->rxtx_annotations[ix];
	279	anno_type = annotation & RXRPC_TX_ANNO_MASK;
	280	if (anno_type == RXRPC_TX_ANNO_RETRANS \|\|
	281	anno_type == RXRPC_TX_ANNO_NAK) {
	282	annotation &= ~RXRPC_TX_ANNO_MASK;
	283	annotation \|= RXRPC_TX_ANNO_UNACK;
	284	}
	285	annotation \|= RXRPC_TX_ANNO_RESENT;
	286	call->rxtx_annotations[ix] = annotation;
	287	}
248f219c DH	288
	289	if (after(call->tx_hard_ack, seq))
	290	seq = call->tx_hard_ack;
dfa7d920	291	}
248f219c DH	292
	293	out_unlock:
	294	spin_unlock_bh(&call->lock);
57494343	295	out:
248f219c	296	_leave("");
17926a79 DH	297	}
	298
	299	/*
248f219c	300	* Handle retransmission and deferred ACK/abort generation.
17926a79 DH	301	*/
	302	void rxrpc_process_call(struct work_struct *work)
	303	{
	304	struct rxrpc_call *call =
	305	container_of(work, struct rxrpc_call, processor);
bd1fdf8c	306	rxrpc_serial_t *send_ack;
a158bdd3	307	unsigned long now, next, t;
c7e86acf	308	unsigned int iterations = 0;
17926a79	309
e34d4234 DH	310	rxrpc_see_call(call);
e34d4234 DH	311
17926a79	312	//printk("\n--------------------\n");
248f219c DH	313	_enter("{%d,%s,%lx}",
248f219c DH	314	call->debug_id, rxrpc_call_states[call->state], call->events);
17926a79	315
248f219c	316	recheck_state:
c7e86acf DH	317	/* Limit the number of times we do this before returning to the manager */
	318	iterations++;
	319	if (iterations > 5)
	320	goto requeue;
	321
248f219c	322	if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
26cb02aa	323	rxrpc_send_abort_packet(call);
248f219c	324	goto recheck_state;
17926a79 DH	325	}
17926a79 DH	326
248f219c DH	327	if (call->state == RXRPC_CALL_COMPLETE) {
248f219c DH	328	del_timer_sync(&call->timer);
94bc669e	329	rxrpc_notify_socket(call);
248f219c	330	goto out_put;
17926a79 DH	331	}
17926a79 DH	332
a158bdd3 DH	333	/* Work out if any timeouts tripped */
	334	now = jiffies;
	335	t = READ_ONCE(call->expect_rx_by);
	336	if (time_after_eq(now, t)) {
	337	trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
	338	set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	339	}
	340
	341	t = READ_ONCE(call->expect_req_by);
	342	if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST &&
	343	time_after_eq(now, t)) {
	344	trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
	345	set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	346	}
	347
	348	t = READ_ONCE(call->expect_term_by);
	349	if (time_after_eq(now, t)) {
	350	trace_rxrpc_timer(call, rxrpc_timer_exp_hard, now);
	351	set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
	352	}
	353
	354	t = READ_ONCE(call->ack_at);
	355	if (time_after_eq(now, t)) {
	356	trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
	357	cmpxchg(&call->ack_at, t, now + MAX_JIFFY_OFFSET);
	358	set_bit(RXRPC_CALL_EV_ACK, &call->events);
	359	}
	360
bd1fdf8c DH	361	t = READ_ONCE(call->ack_lost_at);
	362	if (time_after_eq(now, t)) {
	363	trace_rxrpc_timer(call, rxrpc_timer_exp_lost_ack, now);
	364	cmpxchg(&call->ack_lost_at, t, now + MAX_JIFFY_OFFSET);
	365	set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
	366	}
	367
415f44e4 DH	368	t = READ_ONCE(call->keepalive_at);
	369	if (time_after_eq(now, t)) {
	370	trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
	371	cmpxchg(&call->keepalive_at, t, now + MAX_JIFFY_OFFSET);
e8c3af6b	372	rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, true,
415f44e4 DH	373	rxrpc_propose_ack_ping_for_keepalive);
	374	set_bit(RXRPC_CALL_EV_PING, &call->events);
	375	}
	376
a158bdd3 DH	377	t = READ_ONCE(call->ping_at);
	378	if (time_after_eq(now, t)) {
	379	trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
	380	cmpxchg(&call->ping_at, t, now + MAX_JIFFY_OFFSET);
	381	set_bit(RXRPC_CALL_EV_PING, &call->events);
	382	}
	383
	384	t = READ_ONCE(call->resend_at);
	385	if (time_after_eq(now, t)) {
	386	trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
	387	cmpxchg(&call->resend_at, t, now + MAX_JIFFY_OFFSET);
	388	set_bit(RXRPC_CALL_EV_RESEND, &call->events);
	389	}
	390
	391	/* Process events */
	392	if (test_and_clear_bit(RXRPC_CALL_EV_EXPIRED, &call->events)) {
1a025028 DH	393	if (test_bit(RXRPC_CALL_RX_HEARD, &call->flags) &&
	394	(int)call->conn->hi_serial - (int)call->rx_serial > 0) {
	395	trace_rxrpc_call_reset(call);
	396	rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ECONNRESET);
	397	} else {
	398	rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ETIME);
	399	}
248f219c	400	set_bit(RXRPC_CALL_EV_ABORT, &call->events);
57494343	401	goto recheck_state;
17926a79 DH	402	}
17926a79 DH	403
bd1fdf8c DH	404	send_ack = NULL;
	405	if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events)) {
	406	call->acks_lost_top = call->tx_top;
e8c3af6b	407	rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, false,
bd1fdf8c DH	408	rxrpc_propose_ack_ping_for_lost_ack);
	409	send_ack = &call->acks_lost_ping;
	410	}
	411
	412	if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) \|\|
	413	send_ack) {
248f219c	414	if (call->ackr_reason) {
bd1fdf8c	415	rxrpc_send_ack_packet(call, false, send_ack);
248f219c	416	goto recheck_state;
17926a79 DH	417	}
	418	}
	419
a5af7e1f	420	if (test_and_clear_bit(RXRPC_CALL_EV_PING, &call->events)) {
bd1fdf8c	421	rxrpc_send_ack_packet(call, true, NULL);
a5af7e1f DH	422	goto recheck_state;
	423	}
	424
405dea1d	425	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events)) {
df0adc78	426	rxrpc_resend(call, now);
248f219c	427	goto recheck_state;
17926a79 DH	428	}
17926a79 DH	429
a158bdd3 DH	430	/* Make sure the timer is restarted */
	431	next = call->expect_rx_by;
	432
	433	#define set(T) { t = READ_ONCE(T); if (time_before(t, next)) next = t; }
3d7682af	434
a158bdd3 DH	435	set(call->expect_req_by);
	436	set(call->expect_term_by);
	437	set(call->ack_at);
bd1fdf8c	438	set(call->ack_lost_at);
a158bdd3	439	set(call->resend_at);
415f44e4	440	set(call->keepalive_at);
a158bdd3 DH	441	set(call->ping_at);
	442
	443	now = jiffies;
	444	if (time_after_eq(now, next))
	445	goto recheck_state;
	446
	447	rxrpc_reduce_call_timer(call, next, now, rxrpc_timer_restart);
17926a79 DH	448
17926a79 DH	449	/* other events may have been raised since we started checking */
c7e86acf DH	450	if (call->events && call->state < RXRPC_CALL_COMPLETE)
c7e86acf DH	451	goto requeue;
17926a79	452
248f219c DH	453	out_put:
	454	rxrpc_put_call(call, rxrpc_call_put);
	455	out:
17926a79	456	_leave("");
c7e86acf DH	457	return;
	458
	459	requeue:
	460	__rxrpc_queue_call(call);
	461	goto out;
17926a79	462	}