Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1496 insertions, 0 deletions

diff --git a/drivers/misc/mic/scif/scif_api.c b/drivers/misc/mic/scif/scif_api.c
new file mode 100644
index 000000000..8dd0ccede
--- /dev/null
+++ b/drivers/misc/mic/scif/scif_api.c
@@ -0,0 +1,1496 @@
+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * Copyright(c) 2014 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * Intel SCIF driver.
+ *
+ */
+#include <linux/scif.h>
+#include "scif_main.h"
+#include "scif_map.h"
+
+static const char * const scif_ep_states[] = {
+	"Unbound",
+	"Bound",
+	"Listening",
+	"Connected",
+	"Connecting",
+	"Mapping",
+	"Closing",
+	"Close Listening",
+	"Disconnected",
+	"Zombie"};
+
+enum conn_async_state {
+	ASYNC_CONN_IDLE = 1,	/* ep setup for async connect */
+	ASYNC_CONN_INPROGRESS,	/* async connect in progress */
+	ASYNC_CONN_FLUSH_WORK	/* async work flush in progress  */
+};
+
+/*
+ * File operations for anonymous inode file associated with a SCIF endpoint,
+ * used in kernel mode SCIF poll. Kernel mode SCIF poll calls portions of the
+ * poll API in the kernel and these take in a struct file *. Since a struct
+ * file is not available to kernel mode SCIF, it uses an anonymous file for
+ * this purpose.
+ */
+const struct file_operations scif_anon_fops = {
+	.owner = THIS_MODULE,
+};
+
+scif_epd_t scif_open(void)
+{
+	struct scif_endpt *ep;
+	int err;
+
+	might_sleep();
+	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
+	if (!ep)
+		goto err_ep_alloc;
+
+	ep->qp_info.qp = kzalloc(sizeof(*ep->qp_info.qp), GFP_KERNEL);
+	if (!ep->qp_info.qp)
+		goto err_qp_alloc;
+
+	err = scif_anon_inode_getfile(ep);
+	if (err)
+		goto err_anon_inode;
+
+	spin_lock_init(&ep->lock);
+	mutex_init(&ep->sendlock);
+	mutex_init(&ep->recvlock);
+
+	scif_rma_ep_init(ep);
+	ep->state = SCIFEP_UNBOUND;
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI open: ep %p success\n", ep);
+	return ep;
+
+err_anon_inode:
+	kfree(ep->qp_info.qp);
+err_qp_alloc:
+	kfree(ep);
+err_ep_alloc:
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(scif_open);
+
+/*
+ * scif_disconnect_ep - Disconnects the endpoint if found
+ * @epd: The end point returned from scif_open()
+ */
+static struct scif_endpt *scif_disconnect_ep(struct scif_endpt *ep)
+{
+	struct scifmsg msg;
+	struct scif_endpt *fep = NULL;
+	struct scif_endpt *tmpep;
+	struct list_head *pos, *tmpq;
+	int err;
+
+	/*
+	 * Wake up any threads blocked in send()/recv() before closing
+	 * out the connection. Grabbing and releasing the send/recv lock
+	 * will ensure that any blocked senders/receivers have exited for
+	 * Ring 0 endpoints. It is a Ring 0 bug to call send/recv after
+	 * close. Ring 3 endpoints are not affected since close will not
+	 * be called while there are IOCTLs executing.
+	 */
+	wake_up_interruptible(&ep->sendwq);
+	wake_up_interruptible(&ep->recvwq);
+	mutex_lock(&ep->sendlock);
+	mutex_unlock(&ep->sendlock);
+	mutex_lock(&ep->recvlock);
+	mutex_unlock(&ep->recvlock);
+
+	/* Remove from the connected list */
+	mutex_lock(&scif_info.connlock);
+	list_for_each_safe(pos, tmpq, &scif_info.connected) {
+		tmpep = list_entry(pos, struct scif_endpt, list);
+		if (tmpep == ep) {
+			list_del(pos);
+			fep = tmpep;
+			spin_lock(&ep->lock);
+			break;
+		}
+	}
+
+	if (!fep) {
+		/*
+		 * The other side has completed the disconnect before
+		 * the end point can be removed from the list. Therefore
+		 * the ep lock is not locked, traverse the disconnected
+		 * list to find the endpoint and release the conn lock.
+		 */
+		list_for_each_safe(pos, tmpq, &scif_info.disconnected) {
+			tmpep = list_entry(pos, struct scif_endpt, list);
+			if (tmpep == ep) {
+				list_del(pos);
+				break;
+			}
+		}
+		mutex_unlock(&scif_info.connlock);
+		return NULL;
+	}
+
+	init_completion(&ep->discon);
+	msg.uop = SCIF_DISCNCT;
+	msg.src = ep->port;
+	msg.dst = ep->peer;
+	msg.payload[0] = (u64)ep;
+	msg.payload[1] = ep->remote_ep;
+
+	err = scif_nodeqp_send(ep->remote_dev, &msg);
+	spin_unlock(&ep->lock);
+	mutex_unlock(&scif_info.connlock);
+
+	if (!err)
+		/* Wait for the remote node to respond with SCIF_DISCNT_ACK */
+		wait_for_completion_timeout(&ep->discon,
+					    SCIF_NODE_ALIVE_TIMEOUT);
+	return ep;
+}
+
+int scif_close(scif_epd_t epd)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	struct scif_endpt *tmpep;
+	struct list_head *pos, *tmpq;
+	enum scif_epd_state oldstate;
+	bool flush_conn;
+
+	dev_dbg(scif_info.mdev.this_device, "SCIFAPI close: ep %p %s\n",
+		ep, scif_ep_states[ep->state]);
+	might_sleep();
+	spin_lock(&ep->lock);
+	flush_conn = (ep->conn_async_state == ASYNC_CONN_INPROGRESS);
+	spin_unlock(&ep->lock);
+
+	if (flush_conn)
+		flush_work(&scif_info.conn_work);
+
+	spin_lock(&ep->lock);
+	oldstate = ep->state;
+
+	ep->state = SCIFEP_CLOSING;
+
+	switch (oldstate) {
+	case SCIFEP_ZOMBIE:
+		dev_err(scif_info.mdev.this_device,
+			"SCIFAPI close: zombie state unexpected\n");
+		/* fall through */
+	case SCIFEP_DISCONNECTED:
+		spin_unlock(&ep->lock);
+		scif_unregister_all_windows(epd);
+		/* Remove from the disconnected list */
+		mutex_lock(&scif_info.connlock);
+		list_for_each_safe(pos, tmpq, &scif_info.disconnected) {
+			tmpep = list_entry(pos, struct scif_endpt, list);
+			if (tmpep == ep) {
+				list_del(pos);
+				break;
+			}
+		}
+		mutex_unlock(&scif_info.connlock);
+		break;
+	case SCIFEP_UNBOUND:
+	case SCIFEP_BOUND:
+	case SCIFEP_CONNECTING:
+		spin_unlock(&ep->lock);
+		break;
+	case SCIFEP_MAPPING:
+	case SCIFEP_CONNECTED:
+	case SCIFEP_CLOSING:
+	{
+		spin_unlock(&ep->lock);
+		scif_unregister_all_windows(epd);
+		scif_disconnect_ep(ep);
+		break;
+	}
+	case SCIFEP_LISTENING:
+	case SCIFEP_CLLISTEN:
+	{
+		struct scif_conreq *conreq;
+		struct scifmsg msg;
+		struct scif_endpt *aep;
+
+		spin_unlock(&ep->lock);
+		mutex_lock(&scif_info.eplock);
+
+		/* remove from listen list */
+		list_for_each_safe(pos, tmpq, &scif_info.listen) {
+			tmpep = list_entry(pos, struct scif_endpt, list);
+			if (tmpep == ep)
+				list_del(pos);
+		}
+		/* Remove any dangling accepts */
+		while (ep->acceptcnt) {
+			aep = list_first_entry(&ep->li_accept,
+					       struct scif_endpt, liacceptlist);
+			list_del(&aep->liacceptlist);
+			scif_put_port(aep->port.port);
+			list_for_each_safe(pos, tmpq, &scif_info.uaccept) {
+				tmpep = list_entry(pos, struct scif_endpt,
+						   miacceptlist);
+				if (tmpep == aep) {
+					list_del(pos);
+					break;
+				}
+			}
+			mutex_unlock(&scif_info.eplock);
+			mutex_lock(&scif_info.connlock);
+			list_for_each_safe(pos, tmpq, &scif_info.connected) {
+				tmpep = list_entry(pos,
+						   struct scif_endpt, list);
+				if (tmpep == aep) {
+					list_del(pos);
+					break;
+				}
+			}
+			list_for_each_safe(pos, tmpq, &scif_info.disconnected) {
+				tmpep = list_entry(pos,
+						   struct scif_endpt, list);
+				if (tmpep == aep) {
+					list_del(pos);
+					break;
+				}
+			}
+			mutex_unlock(&scif_info.connlock);
+			scif_teardown_ep(aep);
+			mutex_lock(&scif_info.eplock);
+			scif_add_epd_to_zombie_list(aep, SCIF_EPLOCK_HELD);
+			ep->acceptcnt--;
+		}
+
+		spin_lock(&ep->lock);
+		mutex_unlock(&scif_info.eplock);
+
+		/* Remove and reject any pending connection requests. */
+		while (ep->conreqcnt) {
+			conreq = list_first_entry(&ep->conlist,
+						  struct scif_conreq, list);
+			list_del(&conreq->list);
+
+			msg.uop = SCIF_CNCT_REJ;
+			msg.dst.node = conreq->msg.src.node;
+			msg.dst.port = conreq->msg.src.port;
+			msg.payload[0] = conreq->msg.payload[0];
+			msg.payload[1] = conreq->msg.payload[1];
+			/*
+			 * No Error Handling on purpose for scif_nodeqp_send().
+			 * If the remote node is lost we still want free the
+			 * connection requests on the self node.
+			 */
+			scif_nodeqp_send(&scif_dev[conreq->msg.src.node],
+					 &msg);
+			ep->conreqcnt--;
+			kfree(conreq);
+		}
+
+		spin_unlock(&ep->lock);
+		/* If a kSCIF accept is waiting wake it up */
+		wake_up_interruptible(&ep->conwq);
+		break;
+	}
+	}
+	scif_put_port(ep->port.port);
+	scif_anon_inode_fput(ep);
+	scif_teardown_ep(ep);
+	scif_add_epd_to_zombie_list(ep, !SCIF_EPLOCK_HELD);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(scif_close);
+
+/**
+ * scif_flush() - Wakes up any blocking accepts. The endpoint will no longer
+ *			accept new connections.
+ * @epd: The end point returned from scif_open()
+ */
+int __scif_flush(scif_epd_t epd)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+
+	switch (ep->state) {
+	case SCIFEP_LISTENING:
+	{
+		ep->state = SCIFEP_CLLISTEN;
+
+		/* If an accept is waiting wake it up */
+		wake_up_interruptible(&ep->conwq);
+		break;
+	}
+	default:
+		break;
+	}
+	return 0;
+}
+
+int scif_bind(scif_epd_t epd, u16 pn)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	int ret = 0;
+	int tmp;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI bind: ep %p %s requested port number %d\n",
+		ep, scif_ep_states[ep->state], pn);
+	if (pn) {
+		/*
+		 * Similar to IETF RFC 1700, SCIF ports below
+		 * SCIF_ADMIN_PORT_END can only be bound by system (or root)
+		 * processes or by processes executed by privileged users.
+		 */
+		if (pn < SCIF_ADMIN_PORT_END && !capable(CAP_SYS_ADMIN)) {
+			ret = -EACCES;
+			goto scif_bind_admin_exit;
+		}
+	}
+
+	spin_lock(&ep->lock);
+	if (ep->state == SCIFEP_BOUND) {
+		ret = -EINVAL;
+		goto scif_bind_exit;
+	} else if (ep->state != SCIFEP_UNBOUND) {
+		ret = -EISCONN;
+		goto scif_bind_exit;
+	}
+
+	if (pn) {
+		tmp = scif_rsrv_port(pn);
+		if (tmp != pn) {
+			ret = -EINVAL;
+			goto scif_bind_exit;
+		}
+	} else {
+		ret = scif_get_new_port();
+		if (ret < 0)
+			goto scif_bind_exit;
+		pn = ret;
+	}
+
+	ep->state = SCIFEP_BOUND;
+	ep->port.node = scif_info.nodeid;
+	ep->port.port = pn;
+	ep->conn_async_state = ASYNC_CONN_IDLE;
+	ret = pn;
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI bind: bound to port number %d\n", pn);
+scif_bind_exit:
+	spin_unlock(&ep->lock);
+scif_bind_admin_exit:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(scif_bind);
+
+int scif_listen(scif_epd_t epd, int backlog)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI listen: ep %p %s\n", ep, scif_ep_states[ep->state]);
+	spin_lock(&ep->lock);
+	switch (ep->state) {
+	case SCIFEP_ZOMBIE:
+	case SCIFEP_CLOSING:
+	case SCIFEP_CLLISTEN:
+	case SCIFEP_UNBOUND:
+	case SCIFEP_DISCONNECTED:
+		spin_unlock(&ep->lock);
+		return -EINVAL;
+	case SCIFEP_LISTENING:
+	case SCIFEP_CONNECTED:
+	case SCIFEP_CONNECTING:
+	case SCIFEP_MAPPING:
+		spin_unlock(&ep->lock);
+		return -EISCONN;
+	case SCIFEP_BOUND:
+		break;
+	}
+
+	ep->state = SCIFEP_LISTENING;
+	ep->backlog = backlog;
+
+	ep->conreqcnt = 0;
+	ep->acceptcnt = 0;
+	INIT_LIST_HEAD(&ep->conlist);
+	init_waitqueue_head(&ep->conwq);
+	INIT_LIST_HEAD(&ep->li_accept);
+	spin_unlock(&ep->lock);
+
+	/*
+	 * Listen status is complete so delete the qp information not needed
+	 * on a listen before placing on the list of listening ep's
+	 */
+	scif_teardown_ep(ep);
+	ep->qp_info.qp = NULL;
+
+	mutex_lock(&scif_info.eplock);
+	list_add_tail(&ep->list, &scif_info.listen);
+	mutex_unlock(&scif_info.eplock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(scif_listen);
+
+/*
+ ************************************************************************
+ * SCIF connection flow:
+ *
+ * 1) A SCIF listening endpoint can call scif_accept(..) to wait for SCIF
+ *	connections via a SCIF_CNCT_REQ message
+ * 2) A SCIF endpoint can initiate a SCIF connection by calling
+ *	scif_connect(..) which calls scif_setup_qp_connect(..) which
+ *	allocates the local qp for the endpoint ring buffer and then sends
+ *	a SCIF_CNCT_REQ to the remote node and waits for a SCIF_CNCT_GNT or
+ *	a SCIF_CNCT_REJ message
+ * 3) The peer node handles a SCIF_CNCT_REQ via scif_cnctreq_resp(..) which
+ *	wakes up any threads blocked in step 1 or sends a SCIF_CNCT_REJ
+ *	message otherwise
+ * 4) A thread blocked waiting for incoming connections allocates its local
+ *	endpoint QP and ring buffer following which it sends a SCIF_CNCT_GNT
+ *	and waits for a SCIF_CNCT_GNT(N)ACK. If the allocation fails then
+ *	the node sends a SCIF_CNCT_REJ message
+ * 5) Upon receipt of a SCIF_CNCT_GNT or a SCIF_CNCT_REJ message the
+ *	connecting endpoint is woken up as part of handling
+ *	scif_cnctgnt_resp(..) following which it maps the remote endpoints'
+ *	QP, updates its outbound QP and sends a SCIF_CNCT_GNTACK message on
+ *	success or a SCIF_CNCT_GNTNACK message on failure and completes
+ *	the scif_connect(..) API
+ * 6) Upon receipt of a SCIF_CNCT_GNT(N)ACK the accepting endpoint blocked
+ *	in step 4 is woken up and completes the scif_accept(..) API
+ * 7) The SCIF connection is now established between the two SCIF endpoints.
+ */
+static int scif_conn_func(struct scif_endpt *ep)
+{
+	int err = 0;
+	struct scifmsg msg;
+	struct device *spdev;
+
+	err = scif_reserve_dma_chan(ep);
+	if (err) {
+		dev_err(&ep->remote_dev->sdev->dev,
+			"%s %d err %d\n", __func__, __LINE__, err);
+		ep->state = SCIFEP_BOUND;
+		goto connect_error_simple;
+	}
+	/* Initiate the first part of the endpoint QP setup */
+	err = scif_setup_qp_connect(ep->qp_info.qp, &ep->qp_info.qp_offset,
+				    SCIF_ENDPT_QP_SIZE, ep->remote_dev);
+	if (err) {
+		dev_err(&ep->remote_dev->sdev->dev,
+			"%s err %d qp_offset 0x%llx\n",
+			__func__, err, ep->qp_info.qp_offset);
+		ep->state = SCIFEP_BOUND;
+		goto connect_error_simple;
+	}
+
+	spdev = scif_get_peer_dev(ep->remote_dev);
+	if (IS_ERR(spdev)) {
+		err = PTR_ERR(spdev);
+		goto cleanup_qp;
+	}
+	/* Format connect message and send it */
+	msg.src = ep->port;
+	msg.dst = ep->conn_port;
+	msg.uop = SCIF_CNCT_REQ;
+	msg.payload[0] = (u64)ep;
+	msg.payload[1] = ep->qp_info.qp_offset;
+	err = _scif_nodeqp_send(ep->remote_dev, &msg);
+	if (err)
+		goto connect_error_dec;
+	scif_put_peer_dev(spdev);
+	/*
+	 * Wait for the remote node to respond with SCIF_CNCT_GNT or
+	 * SCIF_CNCT_REJ message.
+	 */
+	err = wait_event_timeout(ep->conwq, ep->state != SCIFEP_CONNECTING,
+				 SCIF_NODE_ALIVE_TIMEOUT);
+	if (!err) {
+		dev_err(&ep->remote_dev->sdev->dev,
+			"%s %d timeout\n", __func__, __LINE__);
+		ep->state = SCIFEP_BOUND;
+	}
+	spdev = scif_get_peer_dev(ep->remote_dev);
+	if (IS_ERR(spdev)) {
+		err = PTR_ERR(spdev);
+		goto cleanup_qp;
+	}
+	if (ep->state == SCIFEP_MAPPING) {
+		err = scif_setup_qp_connect_response(ep->remote_dev,
+						     ep->qp_info.qp,
+						     ep->qp_info.gnt_pld);
+		/*
+		 * If the resource to map the queue are not available then
+		 * we need to tell the other side to terminate the accept
+		 */
+		if (err) {
+			dev_err(&ep->remote_dev->sdev->dev,
+				"%s %d err %d\n", __func__, __LINE__, err);
+			msg.uop = SCIF_CNCT_GNTNACK;
+			msg.payload[0] = ep->remote_ep;
+			_scif_nodeqp_send(ep->remote_dev, &msg);
+			ep->state = SCIFEP_BOUND;
+			goto connect_error_dec;
+		}
+
+		msg.uop = SCIF_CNCT_GNTACK;
+		msg.payload[0] = ep->remote_ep;
+		err = _scif_nodeqp_send(ep->remote_dev, &msg);
+		if (err) {
+			ep->state = SCIFEP_BOUND;
+			goto connect_error_dec;
+		}
+		ep->state = SCIFEP_CONNECTED;
+		mutex_lock(&scif_info.connlock);
+		list_add_tail(&ep->list, &scif_info.connected);
+		mutex_unlock(&scif_info.connlock);
+		dev_dbg(&ep->remote_dev->sdev->dev,
+			"SCIFAPI connect: ep %p connected\n", ep);
+	} else if (ep->state == SCIFEP_BOUND) {
+		dev_dbg(&ep->remote_dev->sdev->dev,
+			"SCIFAPI connect: ep %p connection refused\n", ep);
+		err = -ECONNREFUSED;
+		goto connect_error_dec;
+	}
+	scif_put_peer_dev(spdev);
+	return err;
+connect_error_dec:
+	scif_put_peer_dev(spdev);
+cleanup_qp:
+	scif_cleanup_ep_qp(ep);
+connect_error_simple:
+	return err;
+}
+
+/*
+ * scif_conn_handler:
+ *
+ * Workqueue handler for servicing non-blocking SCIF connect
+ *
+ */
+void scif_conn_handler(struct work_struct *work)
+{
+	struct scif_endpt *ep;
+
+	do {
+		ep = NULL;
+		spin_lock(&scif_info.nb_connect_lock);
+		if (!list_empty(&scif_info.nb_connect_list)) {
+			ep = list_first_entry(&scif_info.nb_connect_list,
+					      struct scif_endpt, conn_list);
+			list_del(&ep->conn_list);
+		}
+		spin_unlock(&scif_info.nb_connect_lock);
+		if (ep) {
+			ep->conn_err = scif_conn_func(ep);
+			wake_up_interruptible(&ep->conn_pend_wq);
+		}
+	} while (ep);
+}
+
+int __scif_connect(scif_epd_t epd, struct scif_port_id *dst, bool non_block)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	int err = 0;
+	struct scif_dev *remote_dev;
+	struct device *spdev;
+
+	dev_dbg(scif_info.mdev.this_device, "SCIFAPI connect: ep %p %s\n", ep,
+		scif_ep_states[ep->state]);
+
+	if (!scif_dev || dst->node > scif_info.maxid)
+		return -ENODEV;
+
+	might_sleep();
+
+	remote_dev = &scif_dev[dst->node];
+	spdev = scif_get_peer_dev(remote_dev);
+	if (IS_ERR(spdev)) {
+		err = PTR_ERR(spdev);
+		return err;
+	}
+
+	spin_lock(&ep->lock);
+	switch (ep->state) {
+	case SCIFEP_ZOMBIE:
+	case SCIFEP_CLOSING:
+		err = -EINVAL;
+		break;
+	case SCIFEP_DISCONNECTED:
+		if (ep->conn_async_state == ASYNC_CONN_INPROGRESS)
+			ep->conn_async_state = ASYNC_CONN_FLUSH_WORK;
+		else
+			err = -EINVAL;
+		break;
+	case SCIFEP_LISTENING:
+	case SCIFEP_CLLISTEN:
+		err = -EOPNOTSUPP;
+		break;
+	case SCIFEP_CONNECTING:
+	case SCIFEP_MAPPING:
+		if (ep->conn_async_state == ASYNC_CONN_INPROGRESS)
+			err = -EINPROGRESS;
+		else
+			err = -EISCONN;
+		break;
+	case SCIFEP_CONNECTED:
+		if (ep->conn_async_state == ASYNC_CONN_INPROGRESS)
+			ep->conn_async_state = ASYNC_CONN_FLUSH_WORK;
+		else
+			err = -EISCONN;
+		break;
+	case SCIFEP_UNBOUND:
+		err = scif_get_new_port();
+		if (err < 0)
+			break;
+		ep->port.port = err;
+		ep->port.node = scif_info.nodeid;
+		ep->conn_async_state = ASYNC_CONN_IDLE;
+		/* Fall through */
+	case SCIFEP_BOUND:
+		/*
+		 * If a non-blocking connect has been already initiated
+		 * (conn_async_state is either ASYNC_CONN_INPROGRESS or
+		 * ASYNC_CONN_FLUSH_WORK), the end point could end up in
+		 * SCIF_BOUND due an error in the connection process
+		 * (e.g., connection refused) If conn_async_state is
+		 * ASYNC_CONN_INPROGRESS - transition to ASYNC_CONN_FLUSH_WORK
+		 * so that the error status can be collected. If the state is
+		 * already ASYNC_CONN_FLUSH_WORK - then set the error to
+		 * EINPROGRESS since some other thread is waiting to collect
+		 * error status.
+		 */
+		if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) {
+			ep->conn_async_state = ASYNC_CONN_FLUSH_WORK;
+		} else if (ep->conn_async_state == ASYNC_CONN_FLUSH_WORK) {
+			err = -EINPROGRESS;
+		} else {
+			ep->conn_port = *dst;
+			init_waitqueue_head(&ep->sendwq);
+			init_waitqueue_head(&ep->recvwq);
+			init_waitqueue_head(&ep->conwq);
+			ep->conn_async_state = 0;
+
+			if (unlikely(non_block))
+				ep->conn_async_state = ASYNC_CONN_INPROGRESS;
+		}
+		break;
+	}
+
+	if (err || ep->conn_async_state == ASYNC_CONN_FLUSH_WORK)
+			goto connect_simple_unlock1;
+
+	ep->state = SCIFEP_CONNECTING;
+	ep->remote_dev = &scif_dev[dst->node];
+	ep->qp_info.qp->magic = SCIFEP_MAGIC;
+	if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) {
+		init_waitqueue_head(&ep->conn_pend_wq);
+		spin_lock(&scif_info.nb_connect_lock);
+		list_add_tail(&ep->conn_list, &scif_info.nb_connect_list);
+		spin_unlock(&scif_info.nb_connect_lock);
+		err = -EINPROGRESS;
+		schedule_work(&scif_info.conn_work);
+	}
+connect_simple_unlock1:
+	spin_unlock(&ep->lock);
+	scif_put_peer_dev(spdev);
+	if (err) {
+		return err;
+	} else if (ep->conn_async_state == ASYNC_CONN_FLUSH_WORK) {
+		flush_work(&scif_info.conn_work);
+		err = ep->conn_err;
+		spin_lock(&ep->lock);
+		ep->conn_async_state = ASYNC_CONN_IDLE;
+		spin_unlock(&ep->lock);
+	} else {
+		err = scif_conn_func(ep);
+	}
+	return err;
+}
+
+int scif_connect(scif_epd_t epd, struct scif_port_id *dst)
+{
+	return __scif_connect(epd, dst, false);
+}
+EXPORT_SYMBOL_GPL(scif_connect);
+
+/**
+ * scif_accept() - Accept a connection request from the remote node
+ *
+ * The function accepts a connection request from the remote node.  Successful
+ * complete is indicate by a new end point being created and passed back
+ * to the caller for future reference.
+ *
+ * Upon successful complete a zero will be returned and the peer information
+ * will be filled in.
+ *
+ * If the end point is not in the listening state -EINVAL will be returned.
+ *
+ * If during the connection sequence resource allocation fails the -ENOMEM
+ * will be returned.
+ *
+ * If the function is called with the ASYNC flag set and no connection requests
+ * are pending it will return -EAGAIN.
+ *
+ * If the remote side is not sending any connection requests the caller may
+ * terminate this function with a signal.  If so a -EINTR will be returned.
+ */
+int scif_accept(scif_epd_t epd, struct scif_port_id *peer,
+		scif_epd_t *newepd, int flags)
+{
+	struct scif_endpt *lep = (struct scif_endpt *)epd;
+	struct scif_endpt *cep;
+	struct scif_conreq *conreq;
+	struct scifmsg msg;
+	int err;
+	struct device *spdev;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI accept: ep %p %s\n", lep, scif_ep_states[lep->state]);
+
+	if (flags & ~SCIF_ACCEPT_SYNC)
+		return -EINVAL;
+
+	if (!peer || !newepd)
+		return -EINVAL;
+
+	might_sleep();
+	spin_lock(&lep->lock);
+	if (lep->state != SCIFEP_LISTENING) {
+		spin_unlock(&lep->lock);
+		return -EINVAL;
+	}
+
+	if (!lep->conreqcnt && !(flags & SCIF_ACCEPT_SYNC)) {
+		/* No connection request present and we do not want to wait */
+		spin_unlock(&lep->lock);
+		return -EAGAIN;
+	}
+
+	lep->files = current->files;
+retry_connection:
+	spin_unlock(&lep->lock);
+	/* Wait for the remote node to send us a SCIF_CNCT_REQ */
+	err = wait_event_interruptible(lep->conwq,
+				       (lep->conreqcnt ||
+				       (lep->state != SCIFEP_LISTENING)));
+	if (err)
+		return err;
+
+	if (lep->state != SCIFEP_LISTENING)
+		return -EINTR;
+
+	spin_lock(&lep->lock);
+
+	if (!lep->conreqcnt)
+		goto retry_connection;
+
+	/* Get the first connect request off the list */
+	conreq = list_first_entry(&lep->conlist, struct scif_conreq, list);
+	list_del(&conreq->list);
+	lep->conreqcnt--;
+	spin_unlock(&lep->lock);
+
+	/* Fill in the peer information */
+	peer->node = conreq->msg.src.node;
+	peer->port = conreq->msg.src.port;
+
+	cep = kzalloc(sizeof(*cep), GFP_KERNEL);
+	if (!cep) {
+		err = -ENOMEM;
+		goto scif_accept_error_epalloc;
+	}
+	spin_lock_init(&cep->lock);
+	mutex_init(&cep->sendlock);
+	mutex_init(&cep->recvlock);
+	cep->state = SCIFEP_CONNECTING;
+	cep->remote_dev = &scif_dev[peer->node];
+	cep->remote_ep = conreq->msg.payload[0];
+
+	scif_rma_ep_init(cep);
+
+	err = scif_reserve_dma_chan(cep);
+	if (err) {
+		dev_err(scif_info.mdev.this_device,
+			"%s %d err %d\n", __func__, __LINE__, err);
+		goto scif_accept_error_qpalloc;
+	}
+
+	cep->qp_info.qp = kzalloc(sizeof(*cep->qp_info.qp), GFP_KERNEL);
+	if (!cep->qp_info.qp) {
+		err = -ENOMEM;
+		goto scif_accept_error_qpalloc;
+	}
+
+	err = scif_anon_inode_getfile(cep);
+	if (err)
+		goto scif_accept_error_anon_inode;
+
+	cep->qp_info.qp->magic = SCIFEP_MAGIC;
+	spdev = scif_get_peer_dev(cep->remote_dev);
+	if (IS_ERR(spdev)) {
+		err = PTR_ERR(spdev);
+		goto scif_accept_error_map;
+	}
+	err = scif_setup_qp_accept(cep->qp_info.qp, &cep->qp_info.qp_offset,
+				   conreq->msg.payload[1], SCIF_ENDPT_QP_SIZE,
+				   cep->remote_dev);
+	if (err) {
+		dev_dbg(&cep->remote_dev->sdev->dev,
+			"SCIFAPI accept: ep %p new %p scif_setup_qp_accept %d qp_offset 0x%llx\n",
+			lep, cep, err, cep->qp_info.qp_offset);
+		scif_put_peer_dev(spdev);
+		goto scif_accept_error_map;
+	}
+
+	cep->port.node = lep->port.node;
+	cep->port.port = lep->port.port;
+	cep->peer.node = peer->node;
+	cep->peer.port = peer->port;
+	init_waitqueue_head(&cep->sendwq);
+	init_waitqueue_head(&cep->recvwq);
+	init_waitqueue_head(&cep->conwq);
+
+	msg.uop = SCIF_CNCT_GNT;
+	msg.src = cep->port;
+	msg.payload[0] = cep->remote_ep;
+	msg.payload[1] = cep->qp_info.qp_offset;
+	msg.payload[2] = (u64)cep;
+
+	err = _scif_nodeqp_send(cep->remote_dev, &msg);
+	scif_put_peer_dev(spdev);
+	if (err)
+		goto scif_accept_error_map;
+retry:
+	/* Wait for the remote node to respond with SCIF_CNCT_GNT(N)ACK */
+	err = wait_event_timeout(cep->conwq, cep->state != SCIFEP_CONNECTING,
+				 SCIF_NODE_ACCEPT_TIMEOUT);
+	if (!err && scifdev_alive(cep))
+		goto retry;
+	err = !err ? -ENODEV : 0;
+	if (err)
+		goto scif_accept_error_map;
+	kfree(conreq);
+
+	spin_lock(&cep->lock);
+
+	if (cep->state == SCIFEP_CLOSING) {
+		/*
+		 * Remote failed to allocate resources and NAKed the grant.
+		 * There is at this point nothing referencing the new end point.
+		 */
+		spin_unlock(&cep->lock);
+		scif_teardown_ep(cep);
+		kfree(cep);
+
+		/* If call with sync flag then go back and wait. */
+		if (flags & SCIF_ACCEPT_SYNC) {
+			spin_lock(&lep->lock);
+			goto retry_connection;
+		}
+		return -EAGAIN;
+	}
+
+	scif_get_port(cep->port.port);
+	*newepd = (scif_epd_t)cep;
+	spin_unlock(&cep->lock);
+	return 0;
+scif_accept_error_map:
+	scif_anon_inode_fput(cep);
+scif_accept_error_anon_inode:
+	scif_teardown_ep(cep);
+scif_accept_error_qpalloc:
+	kfree(cep);
+scif_accept_error_epalloc:
+	msg.uop = SCIF_CNCT_REJ;
+	msg.dst.node = conreq->msg.src.node;
+	msg.dst.port = conreq->msg.src.port;
+	msg.payload[0] = conreq->msg.payload[0];
+	msg.payload[1] = conreq->msg.payload[1];
+	scif_nodeqp_send(&scif_dev[conreq->msg.src.node], &msg);
+	kfree(conreq);
+	return err;
+}
+EXPORT_SYMBOL_GPL(scif_accept);
+
+/*
+ * scif_msg_param_check:
+ * @epd: The end point returned from scif_open()
+ * @len: Length to receive
+ * @flags: blocking or non blocking
+ *
+ * Validate parameters for messaging APIs scif_send(..)/scif_recv(..).
+ */
+static inline int scif_msg_param_check(scif_epd_t epd, int len, int flags)
+{
+	int ret = -EINVAL;
+
+	if (len < 0)
+		goto err_ret;
+	if (flags && (!(flags & SCIF_RECV_BLOCK)))
+		goto err_ret;
+	ret = 0;
+err_ret:
+	return ret;
+}
+
+static int _scif_send(scif_epd_t epd, void *msg, int len, int flags)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	struct scifmsg notif_msg;
+	int curr_xfer_len = 0, sent_len = 0, write_count;
+	int ret = 0;
+	struct scif_qp *qp = ep->qp_info.qp;
+
+	if (flags & SCIF_SEND_BLOCK)
+		might_sleep();
+
+	spin_lock(&ep->lock);
+	while (sent_len != len && SCIFEP_CONNECTED == ep->state) {
+		write_count = scif_rb_space(&qp->outbound_q);
+		if (write_count) {
+			/* Best effort to send as much data as possible */
+			curr_xfer_len = min(len - sent_len, write_count);
+			ret = scif_rb_write(&qp->outbound_q, msg,
+					    curr_xfer_len);
+			if (ret < 0)
+				break;
+			/* Success. Update write pointer */
+			scif_rb_commit(&qp->outbound_q);
+			/*
+			 * Send a notification to the peer about the
+			 * produced data message.
+			 */
+			notif_msg.src = ep->port;
+			notif_msg.uop = SCIF_CLIENT_SENT;
+			notif_msg.payload[0] = ep->remote_ep;
+			ret = _scif_nodeqp_send(ep->remote_dev, &notif_msg);
+			if (ret)
+				break;
+			sent_len += curr_xfer_len;
+			msg = msg + curr_xfer_len;
+			continue;
+		}
+		curr_xfer_len = min(len - sent_len, SCIF_ENDPT_QP_SIZE - 1);
+		/* Not enough RB space. return for the Non Blocking case */
+		if (!(flags & SCIF_SEND_BLOCK))
+			break;
+
+		spin_unlock(&ep->lock);
+		/* Wait for a SCIF_CLIENT_RCVD message in the Blocking case */
+		ret =
+		wait_event_interruptible(ep->sendwq,
+					 (SCIFEP_CONNECTED != ep->state) ||
+					 (scif_rb_space(&qp->outbound_q) >=
+					 curr_xfer_len));
+		spin_lock(&ep->lock);
+		if (ret)
+			break;
+	}
+	if (sent_len)
+		ret = sent_len;
+	else if (!ret && SCIFEP_CONNECTED != ep->state)
+		ret = SCIFEP_DISCONNECTED == ep->state ?
+			-ECONNRESET : -ENOTCONN;
+	spin_unlock(&ep->lock);
+	return ret;
+}
+
+static int _scif_recv(scif_epd_t epd, void *msg, int len, int flags)
+{
+	int read_size;
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	struct scifmsg notif_msg;
+	int curr_recv_len = 0, remaining_len = len, read_count;
+	int ret = 0;
+	struct scif_qp *qp = ep->qp_info.qp;
+
+	if (flags & SCIF_RECV_BLOCK)
+		might_sleep();
+	spin_lock(&ep->lock);
+	while (remaining_len && (SCIFEP_CONNECTED == ep->state ||
+				 SCIFEP_DISCONNECTED == ep->state)) {
+		read_count = scif_rb_count(&qp->inbound_q, remaining_len);
+		if (read_count) {
+			/*
+			 * Best effort to recv as much data as there
+			 * are bytes to read in the RB particularly
+			 * important for the Non Blocking case.
+			 */
+			curr_recv_len = min(remaining_len, read_count);
+			read_size = scif_rb_get_next(&qp->inbound_q,
+						     msg, curr_recv_len);
+			if (ep->state == SCIFEP_CONNECTED) {
+				/*
+				 * Update the read pointer only if the endpoint
+				 * is still connected else the read pointer
+				 * might no longer exist since the peer has
+				 * freed resources!
+				 */
+				scif_rb_update_read_ptr(&qp->inbound_q);
+				/*
+				 * Send a notification to the peer about the
+				 * consumed data message only if the EP is in
+				 * SCIFEP_CONNECTED state.
+				 */
+				notif_msg.src = ep->port;
+				notif_msg.uop = SCIF_CLIENT_RCVD;
+				notif_msg.payload[0] = ep->remote_ep;
+				ret = _scif_nodeqp_send(ep->remote_dev,
+							&notif_msg);
+				if (ret)
+					break;
+			}
+			remaining_len -= curr_recv_len;
+			msg = msg + curr_recv_len;
+			continue;
+		}
+		/*
+		 * Bail out now if the EP is in SCIFEP_DISCONNECTED state else
+		 * we will keep looping forever.
+		 */
+		if (ep->state == SCIFEP_DISCONNECTED)
+			break;
+		/*
+		 * Return in the Non Blocking case if there is no data
+		 * to read in this iteration.
+		 */
+		if (!(flags & SCIF_RECV_BLOCK))
+			break;
+		curr_recv_len = min(remaining_len, SCIF_ENDPT_QP_SIZE - 1);
+		spin_unlock(&ep->lock);
+		/*
+		 * Wait for a SCIF_CLIENT_SEND message in the blocking case
+		 * or until other side disconnects.
+		 */
+		ret =
+		wait_event_interruptible(ep->recvwq,
+					 SCIFEP_CONNECTED != ep->state ||
+					 scif_rb_count(&qp->inbound_q,
+						       curr_recv_len)
+					 >= curr_recv_len);
+		spin_lock(&ep->lock);
+		if (ret)
+			break;
+	}
+	if (len - remaining_len)
+		ret = len - remaining_len;
+	else if (!ret && ep->state != SCIFEP_CONNECTED)
+		ret = ep->state == SCIFEP_DISCONNECTED ?
+			-ECONNRESET : -ENOTCONN;
+	spin_unlock(&ep->lock);
+	return ret;
+}
+
+/**
+ * scif_user_send() - Send data to connection queue
+ * @epd: The end point returned from scif_open()
+ * @msg: Address to place data
+ * @len: Length to receive
+ * @flags: blocking or non blocking
+ *
+ * This function is called from the driver IOCTL entry point
+ * only and is a wrapper for _scif_send().
+ */
+int scif_user_send(scif_epd_t epd, void __user *msg, int len, int flags)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	int err = 0;
+	int sent_len = 0;
+	char *tmp;
+	int loop_len;
+	int chunk_len = min(len, (1 << (MAX_ORDER + PAGE_SHIFT - 1)));
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI send (U): ep %p %s\n", ep, scif_ep_states[ep->state]);
+	if (!len)
+		return 0;
+
+	err = scif_msg_param_check(epd, len, flags);
+	if (err)
+		goto send_err;
+
+	tmp = kmalloc(chunk_len, GFP_KERNEL);
+	if (!tmp) {
+		err = -ENOMEM;
+		goto send_err;
+	}
+	/*
+	 * Grabbing the lock before breaking up the transfer in
+	 * multiple chunks is required to ensure that messages do
+	 * not get fragmented and reordered.
+	 */
+	mutex_lock(&ep->sendlock);
+	while (sent_len != len) {
+		loop_len = len - sent_len;
+		loop_len = min(chunk_len, loop_len);
+		if (copy_from_user(tmp, msg, loop_len)) {
+			err = -EFAULT;
+			goto send_free_err;
+		}
+		err = _scif_send(epd, tmp, loop_len, flags);
+		if (err < 0)
+			goto send_free_err;
+		sent_len += err;
+		msg += err;
+		if (err != loop_len)
+			goto send_free_err;
+	}
+send_free_err:
+	mutex_unlock(&ep->sendlock);
+	kfree(tmp);
+send_err:
+	return err < 0 ? err : sent_len;
+}
+
+/**
+ * scif_user_recv() - Receive data from connection queue
+ * @epd: The end point returned from scif_open()
+ * @msg: Address to place data
+ * @len: Length to receive
+ * @flags: blocking or non blocking
+ *
+ * This function is called from the driver IOCTL entry point
+ * only and is a wrapper for _scif_recv().
+ */
+int scif_user_recv(scif_epd_t epd, void __user *msg, int len, int flags)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	int err = 0;
+	int recv_len = 0;
+	char *tmp;
+	int loop_len;
+	int chunk_len = min(len, (1 << (MAX_ORDER + PAGE_SHIFT - 1)));
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI recv (U): ep %p %s\n", ep, scif_ep_states[ep->state]);
+	if (!len)
+		return 0;
+
+	err = scif_msg_param_check(epd, len, flags);
+	if (err)
+		goto recv_err;
+
+	tmp = kmalloc(chunk_len, GFP_KERNEL);
+	if (!tmp) {
+		err = -ENOMEM;
+		goto recv_err;
+	}
+	/*
+	 * Grabbing the lock before breaking up the transfer in
+	 * multiple chunks is required to ensure that messages do
+	 * not get fragmented and reordered.
+	 */
+	mutex_lock(&ep->recvlock);
+	while (recv_len != len) {
+		loop_len = len - recv_len;
+		loop_len = min(chunk_len, loop_len);
+		err = _scif_recv(epd, tmp, loop_len, flags);
+		if (err < 0)
+			goto recv_free_err;
+		if (copy_to_user(msg, tmp, err)) {
+			err = -EFAULT;
+			goto recv_free_err;
+		}
+		recv_len += err;
+		msg += err;
+		if (err != loop_len)
+			goto recv_free_err;
+	}
+recv_free_err:
+	mutex_unlock(&ep->recvlock);
+	kfree(tmp);
+recv_err:
+	return err < 0 ? err : recv_len;
+}
+
+/**
+ * scif_send() - Send data to connection queue
+ * @epd: The end point returned from scif_open()
+ * @msg: Address to place data
+ * @len: Length to receive
+ * @flags: blocking or non blocking
+ *
+ * This function is called from the kernel mode only and is
+ * a wrapper for _scif_send().
+ */
+int scif_send(scif_epd_t epd, void *msg, int len, int flags)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	int ret;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI send (K): ep %p %s\n", ep, scif_ep_states[ep->state]);
+	if (!len)
+		return 0;
+
+	ret = scif_msg_param_check(epd, len, flags);
+	if (ret)
+		return ret;
+	if (!ep->remote_dev)
+		return -ENOTCONN;
+	/*
+	 * Grab the mutex lock in the blocking case only
+	 * to ensure messages do not get fragmented/reordered.
+	 * The non blocking mode is protected using spin locks
+	 * in _scif_send().
+	 */
+	if (flags & SCIF_SEND_BLOCK)
+		mutex_lock(&ep->sendlock);
+
+	ret = _scif_send(epd, msg, len, flags);
+
+	if (flags & SCIF_SEND_BLOCK)
+		mutex_unlock(&ep->sendlock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(scif_send);
+
+/**
+ * scif_recv() - Receive data from connection queue
+ * @epd: The end point returned from scif_open()
+ * @msg: Address to place data
+ * @len: Length to receive
+ * @flags: blocking or non blocking
+ *
+ * This function is called from the kernel mode only and is
+ * a wrapper for _scif_recv().
+ */
+int scif_recv(scif_epd_t epd, void *msg, int len, int flags)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	int ret;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI recv (K): ep %p %s\n", ep, scif_ep_states[ep->state]);
+	if (!len)
+		return 0;
+
+	ret = scif_msg_param_check(epd, len, flags);
+	if (ret)
+		return ret;
+	/*
+	 * Grab the mutex lock in the blocking case only
+	 * to ensure messages do not get fragmented/reordered.
+	 * The non blocking mode is protected using spin locks
+	 * in _scif_send().
+	 */
+	if (flags & SCIF_RECV_BLOCK)
+		mutex_lock(&ep->recvlock);
+
+	ret = _scif_recv(epd, msg, len, flags);
+
+	if (flags & SCIF_RECV_BLOCK)
+		mutex_unlock(&ep->recvlock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(scif_recv);
+
+static inline void _scif_poll_wait(struct file *f, wait_queue_head_t *wq,
+				   poll_table *p, struct scif_endpt *ep)
+{
+	/*
+	 * Because poll_wait makes a GFP_KERNEL allocation, give up the lock
+	 * and regrab it afterwards. Because the endpoint state might have
+	 * changed while the lock was given up, the state must be checked
+	 * again after re-acquiring the lock. The code in __scif_pollfd(..)
+	 * does this.
+	 */
+	spin_unlock(&ep->lock);
+	poll_wait(f, wq, p);
+	spin_lock(&ep->lock);
+}
+
+__poll_t
+__scif_pollfd(struct file *f, poll_table *wait, struct scif_endpt *ep)
+{
+	__poll_t mask = 0;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI pollfd: ep %p %s\n", ep, scif_ep_states[ep->state]);
+
+	spin_lock(&ep->lock);
+
+	/* Endpoint is waiting for a non-blocking connect to complete */
+	if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) {
+		_scif_poll_wait(f, &ep->conn_pend_wq, wait, ep);
+		if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) {
+			if (ep->state == SCIFEP_CONNECTED ||
+			    ep->state == SCIFEP_DISCONNECTED ||
+			    ep->conn_err)
+				mask |= EPOLLOUT;
+			goto exit;
+		}
+	}
+
+	/* Endpoint is listening for incoming connection requests */
+	if (ep->state == SCIFEP_LISTENING) {
+		_scif_poll_wait(f, &ep->conwq, wait, ep);
+		if (ep->state == SCIFEP_LISTENING) {
+			if (ep->conreqcnt)
+				mask |= EPOLLIN;
+			goto exit;
+		}
+	}
+
+	/* Endpoint is connected or disconnected */
+	if (ep->state == SCIFEP_CONNECTED || ep->state == SCIFEP_DISCONNECTED) {
+		if (poll_requested_events(wait) & EPOLLIN)
+			_scif_poll_wait(f, &ep->recvwq, wait, ep);
+		if (poll_requested_events(wait) & EPOLLOUT)
+			_scif_poll_wait(f, &ep->sendwq, wait, ep);
+		if (ep->state == SCIFEP_CONNECTED ||
+		    ep->state == SCIFEP_DISCONNECTED) {
+			/* Data can be read without blocking */
+			if (scif_rb_count(&ep->qp_info.qp->inbound_q, 1))
+				mask |= EPOLLIN;
+			/* Data can be written without blocking */
+			if (scif_rb_space(&ep->qp_info.qp->outbound_q))
+				mask |= EPOLLOUT;
+			/* Return EPOLLHUP if endpoint is disconnected */
+			if (ep->state == SCIFEP_DISCONNECTED)
+				mask |= EPOLLHUP;
+			goto exit;
+		}
+	}
+
+	/* Return EPOLLERR if the endpoint is in none of the above states */
+	mask |= EPOLLERR;
+exit:
+	spin_unlock(&ep->lock);
+	return mask;
+}
+
+/**
+ * scif_poll() - Kernel mode SCIF poll
+ * @ufds: Array of scif_pollepd structures containing the end points
+ *	  and events to poll on
+ * @nfds: Size of the ufds array
+ * @timeout_msecs: Timeout in msecs, -ve implies infinite timeout
+ *
+ * The code flow in this function is based on do_poll(..) in select.c
+ *
+ * Returns the number of endpoints which have pending events or 0 in
+ * the event of a timeout. If a signal is used for wake up, -EINTR is
+ * returned.
+ */
+int
+scif_poll(struct scif_pollepd *ufds, unsigned int nfds, long timeout_msecs)
+{
+	struct poll_wqueues table;
+	poll_table *pt;
+	int i, count = 0, timed_out = timeout_msecs == 0;
+	__poll_t mask;
+	u64 timeout = timeout_msecs < 0 ? MAX_SCHEDULE_TIMEOUT
+		: msecs_to_jiffies(timeout_msecs);
+
+	poll_initwait(&table);
+	pt = &table.pt;
+	while (1) {
+		for (i = 0; i < nfds; i++) {
+			pt->_key = ufds[i].events | EPOLLERR | EPOLLHUP;
+			mask = __scif_pollfd(ufds[i].epd->anon,
+					     pt, ufds[i].epd);
+			mask &= ufds[i].events | EPOLLERR | EPOLLHUP;
+			if (mask) {
+				count++;
+				pt->_qproc = NULL;
+			}
+			ufds[i].revents = mask;
+		}
+		pt->_qproc = NULL;
+		if (!count) {
+			count = table.error;
+			if (signal_pending(current))
+				count = -EINTR;
+		}
+		if (count || timed_out)
+			break;
+
+		if (!schedule_timeout_interruptible(timeout))
+			timed_out = 1;
+	}
+	poll_freewait(&table);
+	return count;
+}
+EXPORT_SYMBOL_GPL(scif_poll);
+
+int scif_get_node_ids(u16 *nodes, int len, u16 *self)
+{
+	int online = 0;
+	int offset = 0;
+	int node;
+
+	if (!scif_is_mgmt_node())
+		scif_get_node_info();
+
+	*self = scif_info.nodeid;
+	mutex_lock(&scif_info.conflock);
+	len = min_t(int, len, scif_info.total);
+	for (node = 0; node <= scif_info.maxid; node++) {
+		if (_scifdev_alive(&scif_dev[node])) {
+			online++;
+			if (offset < len)
+				nodes[offset++] = node;
+		}
+	}
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI get_node_ids total %d online %d filled in %d nodes\n",
+		scif_info.total, online, offset);
+	mutex_unlock(&scif_info.conflock);
+
+	return online;
+}
+EXPORT_SYMBOL_GPL(scif_get_node_ids);
+
+static int scif_add_client_dev(struct device *dev, struct subsys_interface *si)
+{
+	struct scif_client *client =
+		container_of(si, struct scif_client, si);
+	struct scif_peer_dev *spdev =
+		container_of(dev, struct scif_peer_dev, dev);
+
+	if (client->probe)
+		client->probe(spdev);
+	return 0;
+}
+
+static void scif_remove_client_dev(struct device *dev,
+				   struct subsys_interface *si)
+{
+	struct scif_client *client =
+		container_of(si, struct scif_client, si);
+	struct scif_peer_dev *spdev =
+		container_of(dev, struct scif_peer_dev, dev);
+
+	if (client->remove)
+		client->remove(spdev);
+}
+
+void scif_client_unregister(struct scif_client *client)
+{
+	subsys_interface_unregister(&client->si);
+}
+EXPORT_SYMBOL_GPL(scif_client_unregister);
+
+int scif_client_register(struct scif_client *client)
+{
+	struct subsys_interface *si = &client->si;
+
+	si->name = client->name;
+	si->subsys = &scif_peer_bus;
+	si->add_dev = scif_add_client_dev;
+	si->remove_dev = scif_remove_client_dev;
+
+	return subsys_interface_register(&client->si);
+}
+EXPORT_SYMBOL_GPL(scif_client_register);