net/smc/smc_close.c - linux - Git at Google

 // 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);
 }
	// 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);
	}