smc: socket closing and linkgroup cleanup

smc_shutdown() and smc_release() handling
delayed linkgroup cleanup for linkgroups without connections

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 441 insertions, 0 deletions

diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c
new file mode 100644
index 000000000000..d70c05b57021
--- /dev/null
+++ b/net/smc/smc_close.c
@@ -0,0 +1,441 @@
+/*
+ *  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 <net/sock.h>
+
+#include "smc.h"
+#include "smc_tx.h"
+#include "smc_cdc.h"
+#include "smc_close.h"
+
+#define SMC_CLOSE_WAIT_TX_PENDS_TIME		(5 * HZ)
+
+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);
+}
+
+static void smc_close_wait_tx_pends(struct smc_sock *smc)
+{
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	struct sock *sk = &smc->sk;
+	signed long timeout;
+
+	timeout = SMC_CLOSE_WAIT_TX_PENDS_TIME;
+	add_wait_queue(sk_sleep(sk), &wait);
+	while (!signal_pending(current) && timeout) {
+		int rc;
+
+		rc = sk_wait_event(sk, &timeout,
+				   !smc_cdc_tx_has_pending(&smc->conn),
+				   &wait);
+		if (rc)
+			break;
+	}
+	remove_wait_queue(sk_sleep(sk), &wait);
+}
+
+/* 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;
+
+	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) ||
+				   (sk->sk_err == ECONNABORTED) ||
+				   (sk->sk_err == ECONNRESET),
+				   &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;
+
+	return smc_cdc_get_slot_and_msg_send(conn);
+}
+
+static 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);
+}
+
+/* terminate smc socket abnormally - active abort
+ * RDMA communication no longer possible
+ */
+void smc_close_active_abort(struct smc_sock *smc)
+{
+	struct smc_cdc_conn_state_flags *txflags =
+		&smc->conn.local_tx_ctrl.conn_state_flags;
+
+	bh_lock_sock(&smc->sk);
+	smc->sk.sk_err = ECONNABORTED;
+	if (smc->clcsock && smc->clcsock->sk) {
+		smc->clcsock->sk->sk_err = ECONNABORTED;
+		smc->clcsock->sk->sk_state_change(smc->clcsock->sk);
+	}
+	switch (smc->sk.sk_state) {
+	case SMC_INIT:
+		smc->sk.sk_state = SMC_PEERABORTWAIT;
+		break;
+	case SMC_APPCLOSEWAIT1:
+	case SMC_APPCLOSEWAIT2:
+		txflags->peer_conn_abort = 1;
+		sock_release(smc->clcsock);
+		if (!smc_cdc_rxed_any_close(&smc->conn))
+			smc->sk.sk_state = SMC_PEERABORTWAIT;
+		else
+			smc->sk.sk_state = SMC_CLOSED;
+		break;
+	case SMC_PEERCLOSEWAIT1:
+	case SMC_PEERCLOSEWAIT2:
+		if (!txflags->peer_conn_closed) {
+			smc->sk.sk_state = SMC_PEERABORTWAIT;
+			txflags->peer_conn_abort = 1;
+			sock_release(smc->clcsock);
+		} else {
+			smc->sk.sk_state = SMC_CLOSED;
+		}
+		break;
+	case SMC_PROCESSABORT:
+	case SMC_APPFINCLOSEWAIT:
+		if (!txflags->peer_conn_closed) {
+			txflags->peer_conn_abort = 1;
+			sock_release(smc->clcsock);
+		}
+		smc->sk.sk_state = SMC_CLOSED;
+		break;
+	case SMC_PEERFINCLOSEWAIT:
+	case SMC_PEERABORTWAIT:
+	case SMC_CLOSED:
+		break;
+	}
+
+	sock_set_flag(&smc->sk, SOCK_DEAD);
+	bh_unlock_sock(&smc->sk);
+	smc->sk.sk_state_change(&smc->sk);
+}
+
+int smc_close_active(struct smc_sock *smc)
+{
+	struct smc_cdc_conn_state_flags *txflags =
+		&smc->conn.local_tx_ctrl.conn_state_flags;
+	long timeout = SMC_MAX_STREAM_WAIT_TIMEOUT;
+	struct smc_connection *conn = &smc->conn;
+	struct sock *sk = &smc->sk;
+	int old_state;
+	int rc = 0;
+
+	if (sock_flag(sk, SOCK_LINGER) &&
+	    !(current->flags & PF_EXITING))
+		timeout = sk->sk_lingertime;
+
+again:
+	old_state = sk->sk_state;
+	switch (old_state) {
+	case SMC_INIT:
+		sk->sk_state = SMC_CLOSED;
+		if (smc->smc_listen_work.func)
+			flush_work(&smc->smc_listen_work);
+		sock_put(sk);
+		break;
+	case SMC_LISTEN:
+		sk->sk_state = SMC_CLOSED;
+		sk->sk_state_change(sk); /* wake up accept */
+		if (smc->clcsock && smc->clcsock->sk) {
+			rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
+			/* wake up kernel_accept of smc_tcp_listen_worker */
+			smc->clcsock->sk->sk_data_ready(smc->clcsock->sk);
+		}
+		release_sock(sk);
+		smc_close_cleanup_listen(sk);
+		flush_work(&smc->tcp_listen_work);
+		lock_sock(sk);
+		break;
+	case SMC_ACTIVE:
+		smc_close_stream_wait(smc, timeout);
+		release_sock(sk);
+		cancel_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;
+		} 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 &&
+		    !txflags->peer_conn_closed) {
+			/* just shutdown wr done, send close request */
+			rc = smc_close_final(conn);
+		}
+		sk->sk_state = SMC_CLOSED;
+		smc_close_wait_tx_pends(smc);
+		break;
+	case SMC_APPCLOSEWAIT1:
+	case SMC_APPCLOSEWAIT2:
+		if (!smc_cdc_rxed_any_close(conn))
+			smc_close_stream_wait(smc, timeout);
+		release_sock(sk);
+		cancel_work_sync(&conn->tx_work);
+		lock_sock(sk);
+		if (sk->sk_err != ECONNABORTED) {
+			/* confirm close from peer */
+			rc = smc_close_final(conn);
+			if (rc)
+				break;
+		}
+		if (smc_cdc_rxed_any_close(conn))
+			/* peer has closed the socket already */
+			sk->sk_state = SMC_CLOSED;
+		else
+			/* peer has just issued a shutdown write */
+			sk->sk_state = SMC_PEERFINCLOSEWAIT;
+		smc_close_wait_tx_pends(smc);
+		break;
+	case SMC_PEERCLOSEWAIT1:
+	case SMC_PEERCLOSEWAIT2:
+	case SMC_PEERFINCLOSEWAIT:
+		/* peer sending PeerConnectionClosed will cause transition */
+		break;
+	case SMC_PROCESSABORT:
+		cancel_work_sync(&conn->tx_work);
+		smc_close_abort(conn);
+		sk->sk_state = SMC_CLOSED;
+		smc_close_wait_tx_pends(smc);
+		break;
+	case SMC_PEERABORTWAIT:
+	case SMC_CLOSED:
+		/* nothing to do, add tracing in future patch */
+		break;
+	}
+
+	if (old_state != sk->sk_state)
+		sk->sk_state_change(&smc->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_ACTIVE:
+	case SMC_APPFINCLOSEWAIT:
+	case SMC_APPCLOSEWAIT1:
+	case SMC_APPCLOSEWAIT2:
+		smc_close_abort(&smc->conn);
+		sk->sk_state = SMC_PROCESSABORT;
+		break;
+	case SMC_PEERCLOSEWAIT1:
+	case SMC_PEERCLOSEWAIT2:
+		if (txflags->peer_done_writing &&
+		    !txflags->peer_conn_closed) {
+			/* just shutdown, but not yet closed locally */
+			smc_close_abort(&smc->conn);
+			sk->sk_state = SMC_PROCESSABORT;
+		} else {
+			sk->sk_state = SMC_CLOSED;
+		}
+		break;
+	case SMC_PEERFINCLOSEWAIT:
+	case SMC_PEERABORTWAIT:
+		sk->sk_state = SMC_CLOSED;
+		break;
+	case SMC_INIT:
+	case SMC_PROCESSABORT:
+	/* nothing to do, add tracing in future patch */
+		break;
+	}
+}
+
+/* Some kind of closing has been received: peer_conn_closed, peer_conn_abort,
+ * or peer_done_writing.
+ * Called under tasklet context.
+ */
+void smc_close_passive_received(struct smc_sock *smc)
+{
+	struct smc_cdc_conn_state_flags *rxflags =
+		&smc->conn.local_rx_ctrl.conn_state_flags;
+	struct sock *sk = &smc->sk;
+	int old_state;
+
+	sk->sk_shutdown |= RCV_SHUTDOWN;
+	if (smc->clcsock && smc->clcsock->sk)
+		smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
+	sock_set_flag(&smc->sk, SOCK_DONE);
+
+	old_state = sk->sk_state;
+
+	if (rxflags->peer_conn_abort) {
+		smc_close_passive_abort_received(smc);
+		goto wakeup;
+	}
+
+	switch (sk->sk_state) {
+	case SMC_INIT:
+		if (atomic_read(&smc->conn.bytes_to_rcv) ||
+		    (rxflags->peer_done_writing &&
+		     !rxflags->peer_conn_closed))
+			sk->sk_state = SMC_APPCLOSEWAIT1;
+		else
+			sk->sk_state = SMC_CLOSED;
+		break;
+	case SMC_ACTIVE:
+		sk->sk_state = SMC_APPCLOSEWAIT1;
+		break;
+	case SMC_PEERCLOSEWAIT1:
+		if (rxflags->peer_done_writing)
+			sk->sk_state = SMC_PEERCLOSEWAIT2;
+		/* fall through to check for closing */
+	case SMC_PEERCLOSEWAIT2:
+	case SMC_PEERFINCLOSEWAIT:
+		if (!smc_cdc_rxed_any_close(&smc->conn))
+			break;
+		if (sock_flag(sk, SOCK_DEAD) &&
+		    (sk->sk_shutdown == SHUTDOWN_MASK)) {
+			/* 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;
+		}
+		break;
+	case SMC_APPCLOSEWAIT1:
+	case SMC_APPCLOSEWAIT2:
+	case SMC_APPFINCLOSEWAIT:
+	case SMC_PEERABORTWAIT:
+	case SMC_PROCESSABORT:
+	case SMC_CLOSED:
+		/* nothing to do, add tracing in future patch */
+		break;
+	}
+
+wakeup:
+	if (old_state != sk->sk_state)
+		sk->sk_state_change(sk);
+	sk->sk_data_ready(sk); /* wakeup blocked rcvbuf consumers */
+	sk->sk_write_space(sk); /* wakeup blocked sndbuf producers */
+
+	if ((sk->sk_state == SMC_CLOSED) &&
+	    (sock_flag(sk, SOCK_DEAD) || (old_state == SMC_INIT))) {
+		smc_conn_free(&smc->conn);
+		schedule_delayed_work(&smc->sock_put_work,
+				      SMC_CLOSE_SOCK_PUT_DELAY);
+	}
+}
+
+void smc_close_sock_put_work(struct work_struct *work)
+{
+	struct smc_sock *smc = container_of(to_delayed_work(work),
+					    struct smc_sock,
+					    sock_put_work);
+
+	sock_put(&smc->sk);
+}
+
+int smc_close_shutdown_write(struct smc_sock *smc)
+{
+	struct smc_connection *conn = &smc->conn;
+	long timeout = SMC_MAX_STREAM_WAIT_TIMEOUT;
+	struct sock *sk = &smc->sk;
+	int old_state;
+	int rc = 0;
+
+	if (sock_flag(sk, SOCK_LINGER))
+		timeout = sk->sk_lingertime;
+
+again:
+	old_state = sk->sk_state;
+	switch (old_state) {
+	case SMC_ACTIVE:
+		smc_close_stream_wait(smc, timeout);
+		release_sock(sk);
+		cancel_work_sync(&conn->tx_work);
+		lock_sock(sk);
+		/* send close wr request */
+		rc = smc_close_wr(conn);
+		if (sk->sk_state == SMC_ACTIVE)
+			sk->sk_state = SMC_PEERCLOSEWAIT1;
+		else
+			goto again;
+		break;
+	case SMC_APPCLOSEWAIT1:
+		/* passive close */
+		if (!smc_cdc_rxed_any_close(conn))
+			smc_close_stream_wait(smc, timeout);
+		release_sock(sk);
+		cancel_work_sync(&conn->tx_work);
+		lock_sock(sk);
+		/* 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(&smc->sk);
+	return rc;
+}