[linux-block.git] / net / smc / smc_close.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 *  Socket Closing - normal and abnormal
 *
 *  Copyright IBM Corp. 2016
 *
 *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
 */

#include <linux/workqueue.h>
#include <linux/sched/signal.h>

#include <net/sock.h>
#include <net/tcp.h>

#include "smc.h"
#include "smc_tx.h"
#include "smc_cdc.h"
#include "smc_close.h"

/* release the clcsock that is assigned to the smc_sock */
void smc_clcsock_release(struct smc_sock *smc)
{
	struct socket *tcp;

	if (smc->listen_smc && current_work() != &smc->smc_listen_work)
		cancel_work_sync(&smc->smc_listen_work);
	mutex_lock(&smc->clcsock_release_lock);
	if (smc->clcsock) {
		tcp = smc->clcsock;
		smc->clcsock = NULL;
		sock_release(tcp);
	}
	mutex_unlock(&smc->clcsock_release_lock);
}

static void smc_close_cleanup_listen(struct sock *parent)
{
	struct sock *sk;

	/* Close non-accepted connections */
	while ((sk = smc_accept_dequeue(parent, NULL)))
		smc_close_non_accepted(sk);
}

/* wait for sndbuf data being transmitted */
static void smc_close_stream_wait(struct smc_sock *smc, long timeout)
{
	DEFINE_WAIT_FUNC(wait, woken_wake_function);
	struct sock *sk = &smc->sk;

	if (!timeout)
		return;

	if (!smc_tx_prepared_sends(&smc->conn))
		return;

	/* Send out corked data remaining in sndbuf */
	smc_tx_pending(&smc->conn);

	smc->wait_close_tx_prepared = 1;
	add_wait_queue(sk_sleep(sk), &wait);
	while (!signal_pending(current) && timeout) {
		int rc;

		rc = sk_wait_event(sk, &timeout,
				   !smc_tx_prepared_sends(&smc->conn) ||
				   READ_ONCE(sk->sk_err) == ECONNABORTED ||
				   READ_ONCE(sk->sk_err) == ECONNRESET ||
				   smc->conn.killed,
				   &wait);
		if (rc)
			break;
	}
	remove_wait_queue(sk_sleep(sk), &wait);
	smc->wait_close_tx_prepared = 0;
}

void smc_close_wake_tx_prepared(struct smc_sock *smc)
{
	if (smc->wait_close_tx_prepared)
		/* wake up socket closing */
		smc->sk.sk_state_change(&smc->sk);
}

static int smc_close_wr(struct smc_connection *conn)
{
	conn->local_tx_ctrl.conn_state_flags.peer_done_writing = 1;

	return smc_cdc_get_slot_and_msg_send(conn);
}

static int smc_close_final(struct smc_connection *conn)
{
	if (atomic_read(&conn->bytes_to_rcv))
		conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
	else
		conn->local_tx_ctrl.conn_state_flags.peer_conn_closed = 1;
	if (conn->killed)
		return -EPIPE;

	return smc_cdc_get_slot_and_msg_send(conn);
}

int smc_close_abort(struct smc_connection *conn)
{
	conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;

	return smc_cdc_get_slot_and_msg_send(conn);
}

static void smc_close_cancel_work(struct smc_sock *smc)
{
	struct sock *sk = &smc->sk;

	release_sock(sk);
	if (cancel_work_sync(&smc->conn.close_work))
		sock_put(sk);
	cancel_delayed_work_sync(&smc->conn.tx_work);
	lock_sock(sk);
}

/* terminate smc socket abnormally - active abort
 * link group is terminated, i.e. RDMA communication no longer possible
 */
void smc_close_active_abort(struct smc_sock *smc)
{
	struct sock *sk = &smc->sk;
	bool release_clcsock = false;

	if (sk->sk_state != SMC_INIT && smc->clcsock && smc->clcsock->sk) {
		sk->sk_err = ECONNABORTED;
		if (smc->clcsock && smc->clcsock->sk)
			tcp_abort(smc->clcsock->sk, ECONNABORTED);
	}
	switch (sk->sk_state) {
	case SMC_ACTIVE:
	case SMC_APPCLOSEWAIT1:
	case SMC_APPCLOSEWAIT2:
		sk->sk_state = SMC_PEERABORTWAIT;
		smc_close_cancel_work(smc);
		if (sk->sk_state != SMC_PEERABORTWAIT)
			break;
		sk->sk_state = SMC_CLOSED;
		sock_put(sk); /* (postponed) passive closing */
		break;
	case SMC_PEERCLOSEWAIT1:
	case SMC_PEERCLOSEWAIT2:
	case SMC_PEERFINCLOSEWAIT:
		sk->sk_state = SMC_PEERABORTWAIT;
		smc_close_cancel_work(smc);
		if (sk->sk_state != SMC_PEERABORTWAIT)
			break;
		sk->sk_state = SMC_CLOSED;
		smc_conn_free(&smc->conn);
		release_clcsock = true;
		sock_put(sk); /* passive closing */
		break;
	case SMC_PROCESSABORT:
	case SMC_APPFINCLOSEWAIT:
		sk->sk_state = SMC_PEERABORTWAIT;
		smc_close_cancel_work(smc);
		if (sk->sk_state != SMC_PEERABORTWAIT)
			break;
		sk->sk_state = SMC_CLOSED;
		smc_conn_free(&smc->conn);
		release_clcsock = true;
		break;
	case SMC_INIT:
	case SMC_PEERABORTWAIT:
	case SMC_CLOSED:
		break;
	}

	smc_sock_set_flag(sk, SOCK_DEAD);
	sk->sk_state_change(sk);

	if (release_clcsock) {
		release_sock(sk);
		smc_clcsock_release(smc);
		lock_sock(sk);
	}
}

static inline bool smc_close_sent_any_close(struct smc_connection *conn)
{
	return conn->local_tx_ctrl.conn_state_flags.peer_conn_abort ||
	       conn->local_tx_ctrl.conn_state_flags.peer_conn_closed;
}

int smc_close_active(struct smc_sock *smc)
{
	struct smc_cdc_conn_state_flags *txflags =
		&smc->conn.local_tx_ctrl.conn_state_flags;
	struct smc_connection *conn = &smc->conn;
	struct sock *sk = &smc->sk;
	int old_state;
	long timeout;
	int rc = 0;
	int rc1 = 0;

	timeout = current->flags & PF_EXITING ?
		  0 : sock_flag(sk, SOCK_LINGER) ?
		      sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;

	old_state = sk->sk_state;
again:
	switch (sk->sk_state) {
	case SMC_INIT:
		sk->sk_state = SMC_CLOSED;
		break;
	case SMC_LISTEN:
		sk->sk_state = SMC_CLOSED;
		sk->sk_state_change(sk); /* wake up accept */
		if (smc->clcsock && smc->clcsock->sk) {
			write_lock_bh(&smc->clcsock->sk->sk_callback_lock);
			smc_clcsock_restore_cb(&smc->clcsock->sk->sk_data_ready,
					       &smc->clcsk_data_ready);
			smc->clcsock->sk->sk_user_data = NULL;
			write_unlock_bh(&smc->clcsock->sk->sk_callback_lock);
			rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
		}
		smc_close_cleanup_listen(sk);
		release_sock(sk);
		flush_work(&smc->tcp_listen_work);
		lock_sock(sk);
		break;
	case SMC_ACTIVE:
		smc_close_stream_wait(smc, timeout);
		release_sock(sk);
		cancel_delayed_work_sync(&conn->tx_work);
		lock_sock(sk);
		if (sk->sk_state == SMC_ACTIVE) {
			/* send close request */
			rc = smc_close_final(conn);
			sk->sk_state = SMC_PEERCLOSEWAIT1;

			/* actively shutdown clcsock before peer close it,
			 * prevent peer from entering TIME_WAIT state.
			 */
			if (smc->clcsock && smc->clcsock->sk) {
				rc1 = kernel_sock_shutdown(smc->clcsock,
							   SHUT_RDWR);
				rc = rc ? rc : rc1;
			}
		} else {
			/* peer event has changed the state */
			goto again;
		}
		break;
	case SMC_APPFINCLOSEWAIT:
		/* socket already shutdown wr or both (active close) */
		if (txflags->peer_done_writing &&
		    !smc_close_sent_any_close(conn)) {
			/* just shutdown wr done, send close request */
			rc = smc_close_final(conn);
		}
		sk->sk_state = SMC_CLOSED;
		break;
	case SMC_APPCLOSEWAIT1:
	case SMC_APPCLOSEWAIT2:
		if (!smc_cdc_rxed_any_close(conn))
			smc_close_stream_wait(smc, timeout);
		release_sock(sk);
		cancel_delayed_work_sync(&conn->tx_work);
		lock_sock(sk);
		if (sk->sk_state != SMC_APPCLOSEWAIT1 &&
		    sk->sk_state != SMC_APPCLOSEWAIT2)
			goto again;
		/* confirm close from peer */
		rc = smc_close_final(conn);
		if (smc_cdc_rxed_any_close(conn)) {
			/* peer has closed the socket already */
			sk->sk_state = SMC_CLOSED;
			sock_put(sk); /* postponed passive closing */
		} else {
			/* peer has just issued a shutdown write */
			sk->sk_state = SMC_PEERFINCLOSEWAIT;
		}
		break;
	case SMC_PEERCLOSEWAIT1:
	case SMC_PEERCLOSEWAIT2:
		if (txflags->peer_done_writing &&
		    !smc_close_sent_any_close(conn)) {
			/* just shutdown wr done, send close request */
			rc = smc_close_final(conn);
		}
		/* peer sending PeerConnectionClosed will cause transition */
		break;
	case SMC_PEERFINCLOSEWAIT:
		/* peer sending PeerConnectionClosed will cause transition */
		break;
	case SMC_PROCESSABORT:
		rc = smc_close_abort(conn);
		sk->sk_state = SMC_CLOSED;
		break;
	case SMC_PEERABORTWAIT:
		sk->sk_state = SMC_CLOSED;
		break;
	case SMC_CLOSED:
		/* nothing to do, add tracing in future patch */
		break;
	}

	if (old_state != sk->sk_state)
		sk->sk_state_change(sk);
	return rc;
}

static void smc_close_passive_abort_received(struct smc_sock *smc)
{
	struct smc_cdc_conn_state_flags *txflags =
		&smc->conn.local_tx_ctrl.conn_state_flags;
	struct sock *sk = &smc->sk;

	switch (sk->sk_state) {
	case SMC_INIT:
	case SMC_ACTIVE:
	case SMC_APPCLOSEWAIT1:
		sk->sk_state = SMC_PROCESSABORT;
		sock_put(sk); /* passive closing */
		break;
	case SMC_APPFINCLOSEWAIT:
		sk->sk_state = SMC_PROCESSABORT;
		break;
	case SMC_PEERCLOSEWAIT1:
	case SMC_PEERCLOSEWAIT2:
		if (txflags->peer_done_writing &&
		    !smc_close_sent_any_close(&smc->conn))
			/* just shutdown, but not yet closed locally */
			sk->sk_state = SMC_PROCESSABORT;
		else
			sk->sk_state = SMC_CLOSED;
		sock_put(sk); /* passive closing */
		break;
	case SMC_APPCLOSEWAIT2:
	case SMC_PEERFINCLOSEWAIT:
		sk->sk_state = SMC_CLOSED;
		sock_put(sk); /* passive closing */
		break;
	case SMC_PEERABORTWAIT:
		sk->sk_state = SMC_CLOSED;
		break;
	case SMC_PROCESSABORT:
	/* nothing to do, add tracing in future patch */
		break;
	}
}

/* Either some kind of closing has been received: peer_conn_closed,
 * peer_conn_abort, or peer_done_writing
 * or the link group of the connection terminates abnormally.
 */
static void smc_close_passive_work(struct work_struct *work)
{
	struct smc_connection *conn = container_of(work,
						   struct smc_connection,
						   close_work);
	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
	struct smc_cdc_conn_state_flags *rxflags;
	bool release_clcsock = false;
	struct sock *sk = &smc->sk;
	int old_state;

	lock_sock(sk);
	old_state = sk->sk_state;

	rxflags = &conn->local_rx_ctrl.conn_state_flags;
	if (rxflags->peer_conn_abort) {
		/* peer has not received all data */
		smc_close_passive_abort_received(smc);
		release_sock(sk);
		cancel_delayed_work_sync(&conn->tx_work);
		lock_sock(sk);
		goto wakeup;
	}

	switch (sk->sk_state) {
	case SMC_INIT:
		sk->sk_state = SMC_APPCLOSEWAIT1;
		break;
	case SMC_ACTIVE:
		sk->sk_state = SMC_APPCLOSEWAIT1;
		/* postpone sock_put() for passive closing to cover
		 * received SEND_SHUTDOWN as well
		 */
		break;
	case SMC_PEERCLOSEWAIT1:
		if (rxflags->peer_done_writing)
			sk->sk_state = SMC_PEERCLOSEWAIT2;
		fallthrough;
		/* to check for closing */
	case SMC_PEERCLOSEWAIT2:
		if (!smc_cdc_rxed_any_close(conn))
			break;
		if (sock_flag(sk, SOCK_DEAD) &&
		    smc_close_sent_any_close(conn)) {
			/* smc_release has already been called locally */
			sk->sk_state = SMC_CLOSED;
		} else {
			/* just shutdown, but not yet closed locally */
			sk->sk_state = SMC_APPFINCLOSEWAIT;
		}
		sock_put(sk); /* passive closing */
		break;
	case SMC_PEERFINCLOSEWAIT:
		if (smc_cdc_rxed_any_close(conn)) {
			sk->sk_state = SMC_CLOSED;
			sock_put(sk); /* passive closing */
		}
		break;
	case SMC_APPCLOSEWAIT1:
	case SMC_APPCLOSEWAIT2:
		/* postpone sock_put() for passive closing to cover
		 * received SEND_SHUTDOWN as well
		 */
		break;
	case SMC_APPFINCLOSEWAIT:
	case SMC_PEERABORTWAIT:
	case SMC_PROCESSABORT:
	case SMC_CLOSED:
		/* nothing to do, add tracing in future patch */
		break;
	}

wakeup:
	sk->sk_data_ready(sk); /* wakeup blocked rcvbuf consumers */
	sk->sk_write_space(sk); /* wakeup blocked sndbuf producers */

	if (old_state != sk->sk_state) {
		sk->sk_state_change(sk);
		if ((sk->sk_state == SMC_CLOSED) &&
		    (sock_flag(sk, SOCK_DEAD) || !sk->sk_socket)) {
			smc_conn_free(conn);
			if (smc->clcsock)
				release_clcsock = true;
		}
	}
	release_sock(sk);
	if (release_clcsock)
		smc_clcsock_release(smc);
	sock_put(sk); /* sock_hold done by schedulers of close_work */
}

int smc_close_shutdown_write(struct smc_sock *smc)
{
	struct smc_connection *conn = &smc->conn;
	struct sock *sk = &smc->sk;
	int old_state;
	long timeout;
	int rc = 0;

	timeout = current->flags & PF_EXITING ?
		  0 : sock_flag(sk, SOCK_LINGER) ?
		      sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;

	old_state = sk->sk_state;
again:
	switch (sk->sk_state) {
	case SMC_ACTIVE:
		smc_close_stream_wait(smc, timeout);
		release_sock(sk);
		cancel_delayed_work_sync(&conn->tx_work);
		lock_sock(sk);
		if (sk->sk_state != SMC_ACTIVE)
			goto again;
		/* send close wr request */
		rc = smc_close_wr(conn);
		sk->sk_state = SMC_PEERCLOSEWAIT1;
		break;
	case SMC_APPCLOSEWAIT1:
		/* passive close */
		if (!smc_cdc_rxed_any_close(conn))
			smc_close_stream_wait(smc, timeout);
		release_sock(sk);
		cancel_delayed_work_sync(&conn->tx_work);
		lock_sock(sk);
		if (sk->sk_state != SMC_APPCLOSEWAIT1)
			goto again;
		/* confirm close from peer */
		rc = smc_close_wr(conn);
		sk->sk_state = SMC_APPCLOSEWAIT2;
		break;
	case SMC_APPCLOSEWAIT2:
	case SMC_PEERFINCLOSEWAIT:
	case SMC_PEERCLOSEWAIT1:
	case SMC_PEERCLOSEWAIT2:
	case SMC_APPFINCLOSEWAIT:
	case SMC_PROCESSABORT:
	case SMC_PEERABORTWAIT:
		/* nothing to do, add tracing in future patch */
		break;
	}

	if (old_state != sk->sk_state)
		sk->sk_state_change(sk);
	return rc;
}

/* Initialize close properties on connection establishment. */
void smc_close_init(struct smc_sock *smc)
{
	INIT_WORK(&smc->conn.close_work, smc_close_passive_work);
}
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Shared Memory Communications over RDMA (SMC-R) and RoCE
	4	*
	5	* Socket Closing - normal and abnormal
	6	*
	7	* Copyright IBM Corp. 2016
	8	*
	9	* Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
	10	*/
	11
	12	#include <linux/workqueue.h>
	13	#include <linux/sched/signal.h>
	14
	15	#include <net/sock.h>
	16	#include <net/tcp.h>
	17
	18	#include "smc.h"
	19	#include "smc_tx.h"
	20	#include "smc_cdc.h"
	21	#include "smc_close.h"
	22
	23	/* release the clcsock that is assigned to the smc_sock */
	24	void smc_clcsock_release(struct smc_sock *smc)
	25	{
	26	struct socket *tcp;
	27
	28	if (smc->listen_smc && current_work() != &smc->smc_listen_work)
	29	cancel_work_sync(&smc->smc_listen_work);
	30	mutex_lock(&smc->clcsock_release_lock);
	31	if (smc->clcsock) {
	32	tcp = smc->clcsock;
	33	smc->clcsock = NULL;
	34	sock_release(tcp);
	35	}
	36	mutex_unlock(&smc->clcsock_release_lock);
	37	}
	38
	39	static void smc_close_cleanup_listen(struct sock *parent)
	40	{
	41	struct sock *sk;
	42
	43	/* Close non-accepted connections */
	44	while ((sk = smc_accept_dequeue(parent, NULL)))
	45	smc_close_non_accepted(sk);
	46	}
	47
	48	/* wait for sndbuf data being transmitted */
	49	static void smc_close_stream_wait(struct smc_sock *smc, long timeout)
	50	{
	51	DEFINE_WAIT_FUNC(wait, woken_wake_function);
	52	struct sock *sk = &smc->sk;
	53
	54	if (!timeout)
	55	return;
	56
	57	if (!smc_tx_prepared_sends(&smc->conn))
	58	return;
	59
	60	/* Send out corked data remaining in sndbuf */
	61	smc_tx_pending(&smc->conn);
	62
	63	smc->wait_close_tx_prepared = 1;
	64	add_wait_queue(sk_sleep(sk), &wait);
	65	while (!signal_pending(current) && timeout) {
	66	int rc;
	67
	68	rc = sk_wait_event(sk, &timeout,
	69	!smc_tx_prepared_sends(&smc->conn) \|\|
	70	READ_ONCE(sk->sk_err) == ECONNABORTED \|\|
	71	READ_ONCE(sk->sk_err) == ECONNRESET \|\|
	72	smc->conn.killed,
	73	&wait);
	74	if (rc)
	75	break;
	76	}
	77	remove_wait_queue(sk_sleep(sk), &wait);
	78	smc->wait_close_tx_prepared = 0;
	79	}
	80
	81	void smc_close_wake_tx_prepared(struct smc_sock *smc)
	82	{
	83	if (smc->wait_close_tx_prepared)
	84	/* wake up socket closing */
	85	smc->sk.sk_state_change(&smc->sk);
	86	}
	87
	88	static int smc_close_wr(struct smc_connection *conn)
	89	{
	90	conn->local_tx_ctrl.conn_state_flags.peer_done_writing = 1;
	91
	92	return smc_cdc_get_slot_and_msg_send(conn);
	93	}
	94
	95	static int smc_close_final(struct smc_connection *conn)
	96	{
	97	if (atomic_read(&conn->bytes_to_rcv))
	98	conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
	99	else
	100	conn->local_tx_ctrl.conn_state_flags.peer_conn_closed = 1;
	101	if (conn->killed)
	102	return -EPIPE;
	103
	104	return smc_cdc_get_slot_and_msg_send(conn);
	105	}
	106
	107	int smc_close_abort(struct smc_connection *conn)
	108	{
	109	conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
	110
	111	return smc_cdc_get_slot_and_msg_send(conn);
	112	}
	113
	114	static void smc_close_cancel_work(struct smc_sock *smc)
	115	{
	116	struct sock *sk = &smc->sk;
	117
	118	release_sock(sk);
	119	if (cancel_work_sync(&smc->conn.close_work))
	120	sock_put(sk);
	121	cancel_delayed_work_sync(&smc->conn.tx_work);
	122	lock_sock(sk);
	123	}
	124
	125	/* terminate smc socket abnormally - active abort
	126	* link group is terminated, i.e. RDMA communication no longer possible
	127	*/
	128	void smc_close_active_abort(struct smc_sock *smc)
	129	{
	130	struct sock *sk = &smc->sk;
	131	bool release_clcsock = false;
	132
	133	if (sk->sk_state != SMC_INIT && smc->clcsock && smc->clcsock->sk) {
	134	sk->sk_err = ECONNABORTED;
	135	if (smc->clcsock && smc->clcsock->sk)
	136	tcp_abort(smc->clcsock->sk, ECONNABORTED);
	137	}
	138	switch (sk->sk_state) {
	139	case SMC_ACTIVE:
	140	case SMC_APPCLOSEWAIT1:
	141	case SMC_APPCLOSEWAIT2:
	142	sk->sk_state = SMC_PEERABORTWAIT;
	143	smc_close_cancel_work(smc);
	144	if (sk->sk_state != SMC_PEERABORTWAIT)
	145	break;
	146	sk->sk_state = SMC_CLOSED;
	147	sock_put(sk); /* (postponed) passive closing */
	148	break;
	149	case SMC_PEERCLOSEWAIT1:
	150	case SMC_PEERCLOSEWAIT2:
	151	case SMC_PEERFINCLOSEWAIT:
	152	sk->sk_state = SMC_PEERABORTWAIT;
	153	smc_close_cancel_work(smc);
	154	if (sk->sk_state != SMC_PEERABORTWAIT)
	155	break;
	156	sk->sk_state = SMC_CLOSED;
	157	smc_conn_free(&smc->conn);
	158	release_clcsock = true;
	159	sock_put(sk); /* passive closing */
	160	break;
	161	case SMC_PROCESSABORT:
	162	case SMC_APPFINCLOSEWAIT:
	163	sk->sk_state = SMC_PEERABORTWAIT;
	164	smc_close_cancel_work(smc);
	165	if (sk->sk_state != SMC_PEERABORTWAIT)
	166	break;
	167	sk->sk_state = SMC_CLOSED;
	168	smc_conn_free(&smc->conn);
	169	release_clcsock = true;
	170	break;
	171	case SMC_INIT:
	172	case SMC_PEERABORTWAIT:
	173	case SMC_CLOSED:
	174	break;
	175	}
	176
	177	smc_sock_set_flag(sk, SOCK_DEAD);
	178	sk->sk_state_change(sk);
	179
	180	if (release_clcsock) {
	181	release_sock(sk);
	182	smc_clcsock_release(smc);
	183	lock_sock(sk);
	184	}
	185	}
	186
	187	static inline bool smc_close_sent_any_close(struct smc_connection *conn)
	188	{
	189	return conn->local_tx_ctrl.conn_state_flags.peer_conn_abort \|\|
	190	conn->local_tx_ctrl.conn_state_flags.peer_conn_closed;
	191	}
	192
	193	int smc_close_active(struct smc_sock *smc)
	194	{
	195	struct smc_cdc_conn_state_flags *txflags =
	196	&smc->conn.local_tx_ctrl.conn_state_flags;
	197	struct smc_connection *conn = &smc->conn;
	198	struct sock *sk = &smc->sk;
	199	int old_state;
	200	long timeout;
	201	int rc = 0;
	202	int rc1 = 0;
	203
	204	timeout = current->flags & PF_EXITING ?
	205	0 : sock_flag(sk, SOCK_LINGER) ?
	206	sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;
	207
	208	old_state = sk->sk_state;
	209	again:
	210	switch (sk->sk_state) {
	211	case SMC_INIT:
	212	sk->sk_state = SMC_CLOSED;
	213	break;
	214	case SMC_LISTEN:
	215	sk->sk_state = SMC_CLOSED;
	216	sk->sk_state_change(sk); /* wake up accept */
	217	if (smc->clcsock && smc->clcsock->sk) {
	218	write_lock_bh(&smc->clcsock->sk->sk_callback_lock);
	219	smc_clcsock_restore_cb(&smc->clcsock->sk->sk_data_ready,
	220	&smc->clcsk_data_ready);
	221	smc->clcsock->sk->sk_user_data = NULL;
	222	write_unlock_bh(&smc->clcsock->sk->sk_callback_lock);
	223	rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
	224	}
	225	smc_close_cleanup_listen(sk);
	226	release_sock(sk);
	227	flush_work(&smc->tcp_listen_work);
	228	lock_sock(sk);
	229	break;
	230	case SMC_ACTIVE:
	231	smc_close_stream_wait(smc, timeout);
	232	release_sock(sk);
	233	cancel_delayed_work_sync(&conn->tx_work);
	234	lock_sock(sk);
	235	if (sk->sk_state == SMC_ACTIVE) {
	236	/* send close request */
	237	rc = smc_close_final(conn);
	238	sk->sk_state = SMC_PEERCLOSEWAIT1;
	239
	240	/* actively shutdown clcsock before peer close it,
	241	* prevent peer from entering TIME_WAIT state.
	242	*/
	243	if (smc->clcsock && smc->clcsock->sk) {
	244	rc1 = kernel_sock_shutdown(smc->clcsock,
	245	SHUT_RDWR);
	246	rc = rc ? rc : rc1;
	247	}
	248	} else {
	249	/* peer event has changed the state */
	250	goto again;
	251	}
	252	break;
	253	case SMC_APPFINCLOSEWAIT:
	254	/* socket already shutdown wr or both (active close) */
	255	if (txflags->peer_done_writing &&
	256	!smc_close_sent_any_close(conn)) {
	257	/* just shutdown wr done, send close request */
	258	rc = smc_close_final(conn);
	259	}
	260	sk->sk_state = SMC_CLOSED;
	261	break;
	262	case SMC_APPCLOSEWAIT1:
	263	case SMC_APPCLOSEWAIT2:
	264	if (!smc_cdc_rxed_any_close(conn))
	265	smc_close_stream_wait(smc, timeout);
	266	release_sock(sk);
	267	cancel_delayed_work_sync(&conn->tx_work);
	268	lock_sock(sk);
	269	if (sk->sk_state != SMC_APPCLOSEWAIT1 &&
	270	sk->sk_state != SMC_APPCLOSEWAIT2)
	271	goto again;
	272	/* confirm close from peer */
	273	rc = smc_close_final(conn);
	274	if (smc_cdc_rxed_any_close(conn)) {
	275	/* peer has closed the socket already */
	276	sk->sk_state = SMC_CLOSED;
	277	sock_put(sk); /* postponed passive closing */
	278	} else {
	279	/* peer has just issued a shutdown write */
	280	sk->sk_state = SMC_PEERFINCLOSEWAIT;
	281	}
	282	break;
	283	case SMC_PEERCLOSEWAIT1:
	284	case SMC_PEERCLOSEWAIT2:
	285	if (txflags->peer_done_writing &&
	286	!smc_close_sent_any_close(conn)) {
	287	/* just shutdown wr done, send close request */
	288	rc = smc_close_final(conn);
	289	}
	290	/* peer sending PeerConnectionClosed will cause transition */
	291	break;
	292	case SMC_PEERFINCLOSEWAIT:
	293	/* peer sending PeerConnectionClosed will cause transition */
	294	break;
	295	case SMC_PROCESSABORT:
	296	rc = smc_close_abort(conn);
	297	sk->sk_state = SMC_CLOSED;
	298	break;
	299	case SMC_PEERABORTWAIT:
	300	sk->sk_state = SMC_CLOSED;
	301	break;
	302	case SMC_CLOSED:
	303	/* nothing to do, add tracing in future patch */
	304	break;
	305	}
	306
	307	if (old_state != sk->sk_state)
	308	sk->sk_state_change(sk);
	309	return rc;
	310	}
	311
	312	static void smc_close_passive_abort_received(struct smc_sock *smc)
	313	{
	314	struct smc_cdc_conn_state_flags *txflags =
	315	&smc->conn.local_tx_ctrl.conn_state_flags;
	316	struct sock *sk = &smc->sk;
	317
	318	switch (sk->sk_state) {
	319	case SMC_INIT:
	320	case SMC_ACTIVE:
	321	case SMC_APPCLOSEWAIT1:
	322	sk->sk_state = SMC_PROCESSABORT;
	323	sock_put(sk); /* passive closing */
	324	break;
	325	case SMC_APPFINCLOSEWAIT:
	326	sk->sk_state = SMC_PROCESSABORT;
	327	break;
	328	case SMC_PEERCLOSEWAIT1:
	329	case SMC_PEERCLOSEWAIT2:
	330	if (txflags->peer_done_writing &&
	331	!smc_close_sent_any_close(&smc->conn))
	332	/* just shutdown, but not yet closed locally */
	333	sk->sk_state = SMC_PROCESSABORT;
	334	else
	335	sk->sk_state = SMC_CLOSED;
	336	sock_put(sk); /* passive closing */
	337	break;
	338	case SMC_APPCLOSEWAIT2:
	339	case SMC_PEERFINCLOSEWAIT:
	340	sk->sk_state = SMC_CLOSED;
	341	sock_put(sk); /* passive closing */
	342	break;
	343	case SMC_PEERABORTWAIT:
	344	sk->sk_state = SMC_CLOSED;
	345	break;
	346	case SMC_PROCESSABORT:
	347	/* nothing to do, add tracing in future patch */
	348	break;
	349	}
	350	}
	351
	352	/* Either some kind of closing has been received: peer_conn_closed,
	353	* peer_conn_abort, or peer_done_writing
	354	* or the link group of the connection terminates abnormally.
	355	*/
	356	static void smc_close_passive_work(struct work_struct *work)
	357	{
	358	struct smc_connection *conn = container_of(work,
	359	struct smc_connection,
	360	close_work);
	361	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
	362	struct smc_cdc_conn_state_flags *rxflags;
	363	bool release_clcsock = false;
	364	struct sock *sk = &smc->sk;
	365	int old_state;
	366
	367	lock_sock(sk);
	368	old_state = sk->sk_state;
	369
	370	rxflags = &conn->local_rx_ctrl.conn_state_flags;
	371	if (rxflags->peer_conn_abort) {
	372	/* peer has not received all data */
	373	smc_close_passive_abort_received(smc);
	374	release_sock(sk);
	375	cancel_delayed_work_sync(&conn->tx_work);
	376	lock_sock(sk);
	377	goto wakeup;
	378	}
	379
	380	switch (sk->sk_state) {
	381	case SMC_INIT:
	382	sk->sk_state = SMC_APPCLOSEWAIT1;
	383	break;
	384	case SMC_ACTIVE:
	385	sk->sk_state = SMC_APPCLOSEWAIT1;
	386	/* postpone sock_put() for passive closing to cover
	387	* received SEND_SHUTDOWN as well
	388	*/
	389	break;
	390	case SMC_PEERCLOSEWAIT1:
	391	if (rxflags->peer_done_writing)
	392	sk->sk_state = SMC_PEERCLOSEWAIT2;
	393	fallthrough;
	394	/* to check for closing */
	395	case SMC_PEERCLOSEWAIT2:
	396	if (!smc_cdc_rxed_any_close(conn))
	397	break;
	398	if (sock_flag(sk, SOCK_DEAD) &&
	399	smc_close_sent_any_close(conn)) {
	400	/* smc_release has already been called locally */
	401	sk->sk_state = SMC_CLOSED;
	402	} else {
	403	/* just shutdown, but not yet closed locally */
	404	sk->sk_state = SMC_APPFINCLOSEWAIT;
	405	}
	406	sock_put(sk); /* passive closing */
	407	break;
	408	case SMC_PEERFINCLOSEWAIT:
	409	if (smc_cdc_rxed_any_close(conn)) {
	410	sk->sk_state = SMC_CLOSED;
	411	sock_put(sk); /* passive closing */
	412	}
	413	break;
	414	case SMC_APPCLOSEWAIT1:
	415	case SMC_APPCLOSEWAIT2:
	416	/* postpone sock_put() for passive closing to cover
	417	* received SEND_SHUTDOWN as well
	418	*/
	419	break;
	420	case SMC_APPFINCLOSEWAIT:
	421	case SMC_PEERABORTWAIT:
	422	case SMC_PROCESSABORT:
	423	case SMC_CLOSED:
	424	/* nothing to do, add tracing in future patch */
	425	break;
	426	}
	427
	428	wakeup:
	429	sk->sk_data_ready(sk); /* wakeup blocked rcvbuf consumers */
	430	sk->sk_write_space(sk); /* wakeup blocked sndbuf producers */
	431
	432	if (old_state != sk->sk_state) {
	433	sk->sk_state_change(sk);
	434	if ((sk->sk_state == SMC_CLOSED) &&
	435	(sock_flag(sk, SOCK_DEAD) \|\| !sk->sk_socket)) {
	436	smc_conn_free(conn);
	437	if (smc->clcsock)
	438	release_clcsock = true;
	439	}
	440	}
	441	release_sock(sk);
	442	if (release_clcsock)
	443	smc_clcsock_release(smc);
	444	sock_put(sk); /* sock_hold done by schedulers of close_work */
	445	}
	446
	447	int smc_close_shutdown_write(struct smc_sock *smc)
	448	{
	449	struct smc_connection *conn = &smc->conn;
	450	struct sock *sk = &smc->sk;
	451	int old_state;
	452	long timeout;
	453	int rc = 0;
	454
	455	timeout = current->flags & PF_EXITING ?
	456	0 : sock_flag(sk, SOCK_LINGER) ?
	457	sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;
	458
	459	old_state = sk->sk_state;
	460	again:
	461	switch (sk->sk_state) {
	462	case SMC_ACTIVE:
	463	smc_close_stream_wait(smc, timeout);
	464	release_sock(sk);
	465	cancel_delayed_work_sync(&conn->tx_work);
	466	lock_sock(sk);
	467	if (sk->sk_state != SMC_ACTIVE)
	468	goto again;
	469	/* send close wr request */
	470	rc = smc_close_wr(conn);
	471	sk->sk_state = SMC_PEERCLOSEWAIT1;
	472	break;
	473	case SMC_APPCLOSEWAIT1:
	474	/* passive close */
	475	if (!smc_cdc_rxed_any_close(conn))
	476	smc_close_stream_wait(smc, timeout);
	477	release_sock(sk);
	478	cancel_delayed_work_sync(&conn->tx_work);
	479	lock_sock(sk);
	480	if (sk->sk_state != SMC_APPCLOSEWAIT1)
	481	goto again;
	482	/* confirm close from peer */
	483	rc = smc_close_wr(conn);
	484	sk->sk_state = SMC_APPCLOSEWAIT2;
	485	break;
	486	case SMC_APPCLOSEWAIT2:
	487	case SMC_PEERFINCLOSEWAIT:
	488	case SMC_PEERCLOSEWAIT1:
	489	case SMC_PEERCLOSEWAIT2:
	490	case SMC_APPFINCLOSEWAIT:
	491	case SMC_PROCESSABORT:
	492	case SMC_PEERABORTWAIT:
	493	/* nothing to do, add tracing in future patch */
	494	break;
	495	}
	496
	497	if (old_state != sk->sk_state)
	498	sk->sk_state_change(sk);
	499	return rc;
	500	}
	501
	502	/* Initialize close properties on connection establishment. */
	503	void smc_close_init(struct smc_sock *smc)
	504	{
	505	INIT_WORK(&smc->conn.close_work, smc_close_passive_work);
	506	}