RDMA: iWARP Connection Manager.

Add an iWARP Connection Manager (CM), which abstracts connection
management for iWARP devices (RNICs).  It is a logical instance of the
xx_cm where xx is the transport type (ib or iw).  The symbols exported
are used by the transport independent rdma_cm module, and are
available also for transport dependent ULPs.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 1019 insertions, 0 deletions

diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
new file mode 100644
index 000000000000..c3fb304a4e86
--- /dev/null
+++ b/drivers/infiniband/core/iwcm.c
@@ -0,0 +1,1019 @@
+/*
+ * Copyright (c) 2004, 2005 Intel Corporation.  All rights reserved.
+ * Copyright (c) 2004 Topspin Corporation.  All rights reserved.
+ * Copyright (c) 2004, 2005 Voltaire Corporation.  All rights reserved.
+ * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
+ * Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
+ * Copyright (c) 2005 Network Appliance, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/idr.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <linux/completion.h>
+
+#include <rdma/iw_cm.h>
+#include <rdma/ib_addr.h>
+
+#include "iwcm.h"
+
+MODULE_AUTHOR("Tom Tucker");
+MODULE_DESCRIPTION("iWARP CM");
+MODULE_LICENSE("Dual BSD/GPL");
+
+static struct workqueue_struct *iwcm_wq;
+struct iwcm_work {
+	struct work_struct work;
+	struct iwcm_id_private *cm_id;
+	struct list_head list;
+	struct iw_cm_event event;
+	struct list_head free_list;
+};
+
+/*
+ * The following services provide a mechanism for pre-allocating iwcm_work
+ * elements.  The design pre-allocates them  based on the cm_id type:
+ *	LISTENING IDS: 	Get enough elements preallocated to handle the
+ *			listen backlog.
+ *	ACTIVE IDS:	4: CONNECT_REPLY, ESTABLISHED, DISCONNECT, CLOSE
+ *	PASSIVE IDS:	3: ESTABLISHED, DISCONNECT, CLOSE
+ *
+ * Allocating them in connect and listen avoids having to deal
+ * with allocation failures on the event upcall from the provider (which
+ * is called in the interrupt context).
+ *
+ * One exception is when creating the cm_id for incoming connection requests.
+ * There are two cases:
+ * 1) in the event upcall, cm_event_handler(), for a listening cm_id.  If
+ *    the backlog is exceeded, then no more connection request events will
+ *    be processed.  cm_event_handler() returns -ENOMEM in this case.  Its up
+ *    to the provider to reject the connectino request.
+ * 2) in the connection request workqueue handler, cm_conn_req_handler().
+ *    If work elements cannot be allocated for the new connect request cm_id,
+ *    then IWCM will call the provider reject method.  This is ok since
+ *    cm_conn_req_handler() runs in the workqueue thread context.
+ */
+
+static struct iwcm_work *get_work(struct iwcm_id_private *cm_id_priv)
+{
+	struct iwcm_work *work;
+
+	if (list_empty(&cm_id_priv->work_free_list))
+		return NULL;
+	work = list_entry(cm_id_priv->work_free_list.next, struct iwcm_work,
+			  free_list);
+	list_del_init(&work->free_list);
+	return work;
+}
+
+static void put_work(struct iwcm_work *work)
+{
+	list_add(&work->free_list, &work->cm_id->work_free_list);
+}
+
+static void dealloc_work_entries(struct iwcm_id_private *cm_id_priv)
+{
+	struct list_head *e, *tmp;
+
+	list_for_each_safe(e, tmp, &cm_id_priv->work_free_list)
+		kfree(list_entry(e, struct iwcm_work, free_list));
+}
+
+static int alloc_work_entries(struct iwcm_id_private *cm_id_priv, int count)
+{
+	struct iwcm_work *work;
+
+	BUG_ON(!list_empty(&cm_id_priv->work_free_list));
+	while (count--) {
+		work = kmalloc(sizeof(struct iwcm_work), GFP_KERNEL);
+		if (!work) {
+			dealloc_work_entries(cm_id_priv);
+			return -ENOMEM;
+		}
+		work->cm_id = cm_id_priv;
+		INIT_LIST_HEAD(&work->list);
+		put_work(work);
+	}
+	return 0;
+}
+
+/*
+ * Save private data from incoming connection requests in the
+ * cm_id_priv so the low level driver doesn't have to.  Adjust
+ * the event ptr to point to the local copy.
+ */
+static int copy_private_data(struct iwcm_id_private *cm_id_priv,
+		       struct iw_cm_event *event)
+{
+	void *p;
+
+	p = kmalloc(event->private_data_len, GFP_ATOMIC);
+	if (!p)
+		return -ENOMEM;
+	memcpy(p, event->private_data, event->private_data_len);
+	event->private_data = p;
+	return 0;
+}
+
+/*
+ * Release a reference on cm_id. If the last reference is being removed
+ * and iw_destroy_cm_id is waiting, wake up the waiting thread.
+ */
+static int iwcm_deref_id(struct iwcm_id_private *cm_id_priv)
+{
+	int ret = 0;
+
+	BUG_ON(atomic_read(&cm_id_priv->refcount)==0);
+	if (atomic_dec_and_test(&cm_id_priv->refcount)) {
+		BUG_ON(!list_empty(&cm_id_priv->work_list));
+		if (waitqueue_active(&cm_id_priv->destroy_comp.wait)) {
+			BUG_ON(cm_id_priv->state != IW_CM_STATE_DESTROYING);
+			BUG_ON(test_bit(IWCM_F_CALLBACK_DESTROY,
+					&cm_id_priv->flags));
+			ret = 1;
+		}
+		complete(&cm_id_priv->destroy_comp);
+	}
+
+	return ret;
+}
+
+static void add_ref(struct iw_cm_id *cm_id)
+{
+	struct iwcm_id_private *cm_id_priv;
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	atomic_inc(&cm_id_priv->refcount);
+}
+
+static void rem_ref(struct iw_cm_id *cm_id)
+{
+	struct iwcm_id_private *cm_id_priv;
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	iwcm_deref_id(cm_id_priv);
+}
+
+static int cm_event_handler(struct iw_cm_id *cm_id, struct iw_cm_event *event);
+
+struct iw_cm_id *iw_create_cm_id(struct ib_device *device,
+				 iw_cm_handler cm_handler,
+				 void *context)
+{
+	struct iwcm_id_private *cm_id_priv;
+
+	cm_id_priv = kzalloc(sizeof(*cm_id_priv), GFP_KERNEL);
+	if (!cm_id_priv)
+		return ERR_PTR(-ENOMEM);
+
+	cm_id_priv->state = IW_CM_STATE_IDLE;
+	cm_id_priv->id.device = device;
+	cm_id_priv->id.cm_handler = cm_handler;
+	cm_id_priv->id.context = context;
+	cm_id_priv->id.event_handler = cm_event_handler;
+	cm_id_priv->id.add_ref = add_ref;
+	cm_id_priv->id.rem_ref = rem_ref;
+	spin_lock_init(&cm_id_priv->lock);
+	atomic_set(&cm_id_priv->refcount, 1);
+	init_waitqueue_head(&cm_id_priv->connect_wait);
+	init_completion(&cm_id_priv->destroy_comp);
+	INIT_LIST_HEAD(&cm_id_priv->work_list);
+	INIT_LIST_HEAD(&cm_id_priv->work_free_list);
+
+	return &cm_id_priv->id;
+}
+EXPORT_SYMBOL(iw_create_cm_id);
+
+
+static int iwcm_modify_qp_err(struct ib_qp *qp)
+{
+	struct ib_qp_attr qp_attr;
+
+	if (!qp)
+		return -EINVAL;
+
+	qp_attr.qp_state = IB_QPS_ERR;
+	return ib_modify_qp(qp, &qp_attr, IB_QP_STATE);
+}
+
+/*
+ * This is really the RDMAC CLOSING state. It is most similar to the
+ * IB SQD QP state.
+ */
+static int iwcm_modify_qp_sqd(struct ib_qp *qp)
+{
+	struct ib_qp_attr qp_attr;
+
+	BUG_ON(qp == NULL);
+	qp_attr.qp_state = IB_QPS_SQD;
+	return ib_modify_qp(qp, &qp_attr, IB_QP_STATE);
+}
+
+/*
+ * CM_ID <-- CLOSING
+ *
+ * Block if a passive or active connection is currenlty being processed. Then
+ * process the event as follows:
+ * - If we are ESTABLISHED, move to CLOSING and modify the QP state
+ *   based on the abrupt flag
+ * - If the connection is already in the CLOSING or IDLE state, the peer is
+ *   disconnecting concurrently with us and we've already seen the
+ *   DISCONNECT event -- ignore the request and return 0
+ * - Disconnect on a listening endpoint returns -EINVAL
+ */
+int iw_cm_disconnect(struct iw_cm_id *cm_id, int abrupt)
+{
+	struct iwcm_id_private *cm_id_priv;
+	unsigned long flags;
+	int ret = 0;
+	struct ib_qp *qp = NULL;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	/* Wait if we're currently in a connect or accept downcall */
+	wait_event(cm_id_priv->connect_wait,
+		   !test_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags));
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	switch (cm_id_priv->state) {
+	case IW_CM_STATE_ESTABLISHED:
+		cm_id_priv->state = IW_CM_STATE_CLOSING;
+
+		/* QP could be <nul> for user-mode client */
+		if (cm_id_priv->qp)
+			qp = cm_id_priv->qp;
+		else
+			ret = -EINVAL;
+		break;
+	case IW_CM_STATE_LISTEN:
+		ret = -EINVAL;
+		break;
+	case IW_CM_STATE_CLOSING:
+		/* remote peer closed first */
+	case IW_CM_STATE_IDLE:
+		/* accept or connect returned !0 */
+		break;
+	case IW_CM_STATE_CONN_RECV:
+		/*
+		 * App called disconnect before/without calling accept after
+		 * connect_request event delivered.
+		 */
+		break;
+	case IW_CM_STATE_CONN_SENT:
+		/* Can only get here if wait above fails */
+	default:
+		BUG();
+	}
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+
+	if (qp) {
+		if (abrupt)
+			ret = iwcm_modify_qp_err(qp);
+		else
+			ret = iwcm_modify_qp_sqd(qp);
+
+		/*
+		 * If both sides are disconnecting the QP could
+		 * already be in ERR or SQD states
+		 */
+		ret = 0;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(iw_cm_disconnect);
+
+/*
+ * CM_ID <-- DESTROYING
+ *
+ * Clean up all resources associated with the connection and release
+ * the initial reference taken by iw_create_cm_id.
+ */
+static void destroy_cm_id(struct iw_cm_id *cm_id)
+{
+	struct iwcm_id_private *cm_id_priv;
+	unsigned long flags;
+	int ret;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	/*
+	 * Wait if we're currently in a connect or accept downcall. A
+	 * listening endpoint should never block here.
+	 */
+	wait_event(cm_id_priv->connect_wait,
+		   !test_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags));
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	switch (cm_id_priv->state) {
+	case IW_CM_STATE_LISTEN:
+		cm_id_priv->state = IW_CM_STATE_DESTROYING;
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		/* destroy the listening endpoint */
+		ret = cm_id->device->iwcm->destroy_listen(cm_id);
+		spin_lock_irqsave(&cm_id_priv->lock, flags);
+		break;
+	case IW_CM_STATE_ESTABLISHED:
+		cm_id_priv->state = IW_CM_STATE_DESTROYING;
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		/* Abrupt close of the connection */
+		(void)iwcm_modify_qp_err(cm_id_priv->qp);
+		spin_lock_irqsave(&cm_id_priv->lock, flags);
+		break;
+	case IW_CM_STATE_IDLE:
+	case IW_CM_STATE_CLOSING:
+		cm_id_priv->state = IW_CM_STATE_DESTROYING;
+		break;
+	case IW_CM_STATE_CONN_RECV:
+		/*
+		 * App called destroy before/without calling accept after
+		 * receiving connection request event notification.
+		 */
+		cm_id_priv->state = IW_CM_STATE_DESTROYING;
+		break;
+	case IW_CM_STATE_CONN_SENT:
+	case IW_CM_STATE_DESTROYING:
+	default:
+		BUG();
+		break;
+	}
+	if (cm_id_priv->qp) {
+		cm_id_priv->id.device->iwcm->rem_ref(cm_id_priv->qp);
+		cm_id_priv->qp = NULL;
+	}
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+
+	(void)iwcm_deref_id(cm_id_priv);
+}
+
+/*
+ * This function is only called by the application thread and cannot
+ * be called by the event thread. The function will wait for all
+ * references to be released on the cm_id and then kfree the cm_id
+ * object.
+ */
+void iw_destroy_cm_id(struct iw_cm_id *cm_id)
+{
+	struct iwcm_id_private *cm_id_priv;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	BUG_ON(test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags));
+
+	destroy_cm_id(cm_id);
+
+	wait_for_completion(&cm_id_priv->destroy_comp);
+
+	dealloc_work_entries(cm_id_priv);
+
+	kfree(cm_id_priv);
+}
+EXPORT_SYMBOL(iw_destroy_cm_id);
+
+/*
+ * CM_ID <-- LISTEN
+ *
+ * Start listening for connect requests. Generates one CONNECT_REQUEST
+ * event for each inbound connect request.
+ */
+int iw_cm_listen(struct iw_cm_id *cm_id, int backlog)
+{
+	struct iwcm_id_private *cm_id_priv;
+	unsigned long flags;
+	int ret = 0;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+
+	ret = alloc_work_entries(cm_id_priv, backlog);
+	if (ret)
+		return ret;
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	switch (cm_id_priv->state) {
+	case IW_CM_STATE_IDLE:
+		cm_id_priv->state = IW_CM_STATE_LISTEN;
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		ret = cm_id->device->iwcm->create_listen(cm_id, backlog);
+		if (ret)
+			cm_id_priv->state = IW_CM_STATE_IDLE;
+		spin_lock_irqsave(&cm_id_priv->lock, flags);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(iw_cm_listen);
+
+/*
+ * CM_ID <-- IDLE
+ *
+ * Rejects an inbound connection request. No events are generated.
+ */
+int iw_cm_reject(struct iw_cm_id *cm_id,
+		 const void *private_data,
+		 u8 private_data_len)
+{
+	struct iwcm_id_private *cm_id_priv;
+	unsigned long flags;
+	int ret;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	set_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	if (cm_id_priv->state != IW_CM_STATE_CONN_RECV) {
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+		wake_up_all(&cm_id_priv->connect_wait);
+		return -EINVAL;
+	}
+	cm_id_priv->state = IW_CM_STATE_IDLE;
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+
+	ret = cm_id->device->iwcm->reject(cm_id, private_data,
+					  private_data_len);
+
+	clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+	wake_up_all(&cm_id_priv->connect_wait);
+
+	return ret;
+}
+EXPORT_SYMBOL(iw_cm_reject);
+
+/*
+ * CM_ID <-- ESTABLISHED
+ *
+ * Accepts an inbound connection request and generates an ESTABLISHED
+ * event. Callers of iw_cm_disconnect and iw_destroy_cm_id will block
+ * until the ESTABLISHED event is received from the provider.
+ */
+int iw_cm_accept(struct iw_cm_id *cm_id,
+		 struct iw_cm_conn_param *iw_param)
+{
+	struct iwcm_id_private *cm_id_priv;
+	struct ib_qp *qp;
+	unsigned long flags;
+	int ret;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	set_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	if (cm_id_priv->state != IW_CM_STATE_CONN_RECV) {
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+		wake_up_all(&cm_id_priv->connect_wait);
+		return -EINVAL;
+	}
+	/* Get the ib_qp given the QPN */
+	qp = cm_id->device->iwcm->get_qp(cm_id->device, iw_param->qpn);
+	if (!qp) {
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		return -EINVAL;
+	}
+	cm_id->device->iwcm->add_ref(qp);
+	cm_id_priv->qp = qp;
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+
+	ret = cm_id->device->iwcm->accept(cm_id, iw_param);
+	if (ret) {
+		/* An error on accept precludes provider events */
+		BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_RECV);
+		cm_id_priv->state = IW_CM_STATE_IDLE;
+		spin_lock_irqsave(&cm_id_priv->lock, flags);
+		if (cm_id_priv->qp) {
+			cm_id->device->iwcm->rem_ref(qp);
+			cm_id_priv->qp = NULL;
+		}
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+		wake_up_all(&cm_id_priv->connect_wait);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(iw_cm_accept);
+
+/*
+ * Active Side: CM_ID <-- CONN_SENT
+ *
+ * If successful, results in the generation of a CONNECT_REPLY
+ * event. iw_cm_disconnect and iw_cm_destroy will block until the
+ * CONNECT_REPLY event is received from the provider.
+ */
+int iw_cm_connect(struct iw_cm_id *cm_id, struct iw_cm_conn_param *iw_param)
+{
+	struct iwcm_id_private *cm_id_priv;
+	int ret = 0;
+	unsigned long flags;
+	struct ib_qp *qp;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+
+	ret = alloc_work_entries(cm_id_priv, 4);
+	if (ret)
+		return ret;
+
+	set_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+
+	if (cm_id_priv->state != IW_CM_STATE_IDLE) {
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+		wake_up_all(&cm_id_priv->connect_wait);
+		return -EINVAL;
+	}
+
+	/* Get the ib_qp given the QPN */
+	qp = cm_id->device->iwcm->get_qp(cm_id->device, iw_param->qpn);
+	if (!qp) {
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		return -EINVAL;
+	}
+	cm_id->device->iwcm->add_ref(qp);
+	cm_id_priv->qp = qp;
+	cm_id_priv->state = IW_CM_STATE_CONN_SENT;
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+
+	ret = cm_id->device->iwcm->connect(cm_id, iw_param);
+	if (ret) {
+		spin_lock_irqsave(&cm_id_priv->lock, flags);
+		if (cm_id_priv->qp) {
+			cm_id->device->iwcm->rem_ref(qp);
+			cm_id_priv->qp = NULL;
+		}
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_SENT);
+		cm_id_priv->state = IW_CM_STATE_IDLE;
+		clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+		wake_up_all(&cm_id_priv->connect_wait);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(iw_cm_connect);
+
+/*
+ * Passive Side: new CM_ID <-- CONN_RECV
+ *
+ * Handles an inbound connect request. The function creates a new
+ * iw_cm_id to represent the new connection and inherits the client
+ * callback function and other attributes from the listening parent.
+ *
+ * The work item contains a pointer to the listen_cm_id and the event. The
+ * listen_cm_id contains the client cm_handler, context and
+ * device. These are copied when the device is cloned. The event
+ * contains the new four tuple.
+ *
+ * An error on the child should not affect the parent, so this
+ * function does not return a value.
+ */
+static void cm_conn_req_handler(struct iwcm_id_private *listen_id_priv,
+				struct iw_cm_event *iw_event)
+{
+	unsigned long flags;
+	struct iw_cm_id *cm_id;
+	struct iwcm_id_private *cm_id_priv;
+	int ret;
+
+	/*
+	 * The provider should never generate a connection request
+	 * event with a bad status.
+	 */
+	BUG_ON(iw_event->status);
+
+	/*
+	 * We could be destroying the listening id. If so, ignore this
+	 * upcall.
+	 */
+	spin_lock_irqsave(&listen_id_priv->lock, flags);
+	if (listen_id_priv->state != IW_CM_STATE_LISTEN) {
+		spin_unlock_irqrestore(&listen_id_priv->lock, flags);
+		return;
+	}
+	spin_unlock_irqrestore(&listen_id_priv->lock, flags);
+
+	cm_id = iw_create_cm_id(listen_id_priv->id.device,
+				listen_id_priv->id.cm_handler,
+				listen_id_priv->id.context);
+	/* If the cm_id could not be created, ignore the request */
+	if (IS_ERR(cm_id))
+		return;
+
+	cm_id->provider_data = iw_event->provider_data;
+	cm_id->local_addr = iw_event->local_addr;
+	cm_id->remote_addr = iw_event->remote_addr;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	cm_id_priv->state = IW_CM_STATE_CONN_RECV;
+
+	ret = alloc_work_entries(cm_id_priv, 3);
+	if (ret) {
+		iw_cm_reject(cm_id, NULL, 0);
+		iw_destroy_cm_id(cm_id);
+		return;
+	}
+
+	/* Call the client CM handler */
+	ret = cm_id->cm_handler(cm_id, iw_event);
+	if (ret) {
+		set_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
+		destroy_cm_id(cm_id);
+		if (atomic_read(&cm_id_priv->refcount)==0)
+			kfree(cm_id);
+	}
+
+	if (iw_event->private_data_len)
+		kfree(iw_event->private_data);
+}
+
+/*
+ * Passive Side: CM_ID <-- ESTABLISHED
+ *
+ * The provider generated an ESTABLISHED event which means that
+ * the MPA negotion has completed successfully and we are now in MPA
+ * FPDU mode.
+ *
+ * This event can only be received in the CONN_RECV state. If the
+ * remote peer closed, the ESTABLISHED event would be received followed
+ * by the CLOSE event. If the app closes, it will block until we wake
+ * it up after processing this event.
+ */
+static int cm_conn_est_handler(struct iwcm_id_private *cm_id_priv,
+			       struct iw_cm_event *iw_event)
+{
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+
+	/*
+	 * We clear the CONNECT_WAIT bit here to allow the callback
+	 * function to call iw_cm_disconnect. Calling iw_destroy_cm_id
+	 * from a callback handler is not allowed.
+	 */
+	clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+	BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_RECV);
+	cm_id_priv->state = IW_CM_STATE_ESTABLISHED;
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+	ret = cm_id_priv->id.cm_handler(&cm_id_priv->id, iw_event);
+	wake_up_all(&cm_id_priv->connect_wait);
+
+	return ret;
+}
+
+/*
+ * Active Side: CM_ID <-- ESTABLISHED
+ *
+ * The app has called connect and is waiting for the established event to
+ * post it's requests to the server. This event will wake up anyone
+ * blocked in iw_cm_disconnect or iw_destroy_id.
+ */
+static int cm_conn_rep_handler(struct iwcm_id_private *cm_id_priv,
+			       struct iw_cm_event *iw_event)
+{
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	/*
+	 * Clear the connect wait bit so a callback function calling
+	 * iw_cm_disconnect will not wait and deadlock this thread
+	 */
+	clear_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags);
+	BUG_ON(cm_id_priv->state != IW_CM_STATE_CONN_SENT);
+	if (iw_event->status == IW_CM_EVENT_STATUS_ACCEPTED) {
+		cm_id_priv->id.local_addr = iw_event->local_addr;
+		cm_id_priv->id.remote_addr = iw_event->remote_addr;
+		cm_id_priv->state = IW_CM_STATE_ESTABLISHED;
+	} else {
+		/* REJECTED or RESET */
+		cm_id_priv->id.device->iwcm->rem_ref(cm_id_priv->qp);
+		cm_id_priv->qp = NULL;
+		cm_id_priv->state = IW_CM_STATE_IDLE;
+	}
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+	ret = cm_id_priv->id.cm_handler(&cm_id_priv->id, iw_event);
+
+	if (iw_event->private_data_len)
+		kfree(iw_event->private_data);
+
+	/* Wake up waiters on connect complete */
+	wake_up_all(&cm_id_priv->connect_wait);
+
+	return ret;
+}
+
+/*
+ * CM_ID <-- CLOSING
+ *
+ * If in the ESTABLISHED state, move to CLOSING.
+ */
+static void cm_disconnect_handler(struct iwcm_id_private *cm_id_priv,
+				  struct iw_cm_event *iw_event)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	if (cm_id_priv->state == IW_CM_STATE_ESTABLISHED)
+		cm_id_priv->state = IW_CM_STATE_CLOSING;
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+}
+
+/*
+ * CM_ID <-- IDLE
+ *
+ * If in the ESTBLISHED or CLOSING states, the QP will have have been
+ * moved by the provider to the ERR state. Disassociate the CM_ID from
+ * the QP,  move to IDLE, and remove the 'connected' reference.
+ *
+ * If in some other state, the cm_id was destroyed asynchronously.
+ * This is the last reference that will result in waking up
+ * the app thread blocked in iw_destroy_cm_id.
+ */
+static int cm_close_handler(struct iwcm_id_private *cm_id_priv,
+				  struct iw_cm_event *iw_event)
+{
+	unsigned long flags;
+	int ret = 0;
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+
+	if (cm_id_priv->qp) {
+		cm_id_priv->id.device->iwcm->rem_ref(cm_id_priv->qp);
+		cm_id_priv->qp = NULL;
+	}
+	switch (cm_id_priv->state) {
+	case IW_CM_STATE_ESTABLISHED:
+	case IW_CM_STATE_CLOSING:
+		cm_id_priv->state = IW_CM_STATE_IDLE;
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		ret = cm_id_priv->id.cm_handler(&cm_id_priv->id, iw_event);
+		spin_lock_irqsave(&cm_id_priv->lock, flags);
+		break;
+	case IW_CM_STATE_DESTROYING:
+		break;
+	default:
+		BUG();
+	}
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+
+	return ret;
+}
+
+static int process_event(struct iwcm_id_private *cm_id_priv,
+			 struct iw_cm_event *iw_event)
+{
+	int ret = 0;
+
+	switch (iw_event->event) {
+	case IW_CM_EVENT_CONNECT_REQUEST:
+		cm_conn_req_handler(cm_id_priv, iw_event);
+		break;
+	case IW_CM_EVENT_CONNECT_REPLY:
+		ret = cm_conn_rep_handler(cm_id_priv, iw_event);
+		break;
+	case IW_CM_EVENT_ESTABLISHED:
+		ret = cm_conn_est_handler(cm_id_priv, iw_event);
+		break;
+	case IW_CM_EVENT_DISCONNECT:
+		cm_disconnect_handler(cm_id_priv, iw_event);
+		break;
+	case IW_CM_EVENT_CLOSE:
+		ret = cm_close_handler(cm_id_priv, iw_event);
+		break;
+	default:
+		BUG();
+	}
+
+	return ret;
+}
+
+/*
+ * Process events on the work_list for the cm_id. If the callback
+ * function requests that the cm_id be deleted, a flag is set in the
+ * cm_id flags to indicate that when the last reference is
+ * removed, the cm_id is to be destroyed. This is necessary to
+ * distinguish between an object that will be destroyed by the app
+ * thread asleep on the destroy_comp list vs. an object destroyed
+ * here synchronously when the last reference is removed.
+ */
+static void cm_work_handler(void *arg)
+{
+	struct iwcm_work *work = arg, lwork;
+	struct iwcm_id_private *cm_id_priv = work->cm_id;
+	unsigned long flags;
+	int empty;
+	int ret = 0;
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	empty = list_empty(&cm_id_priv->work_list);
+	while (!empty) {
+		work = list_entry(cm_id_priv->work_list.next,
+				  struct iwcm_work, list);
+		list_del_init(&work->list);
+		empty = list_empty(&cm_id_priv->work_list);
+		lwork = *work;
+		put_work(work);
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+
+		ret = process_event(cm_id_priv, &work->event);
+		if (ret) {
+			set_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
+			destroy_cm_id(&cm_id_priv->id);
+		}
+		BUG_ON(atomic_read(&cm_id_priv->refcount)==0);
+		if (iwcm_deref_id(cm_id_priv))
+			return;
+
+		if (atomic_read(&cm_id_priv->refcount)==0 &&
+		    test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags)) {
+			dealloc_work_entries(cm_id_priv);
+			kfree(cm_id_priv);
+			return;
+		}
+		spin_lock_irqsave(&cm_id_priv->lock, flags);
+	}
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+}
+
+/*
+ * This function is called on interrupt context. Schedule events on
+ * the iwcm_wq thread to allow callback functions to downcall into
+ * the CM and/or block.  Events are queued to a per-CM_ID
+ * work_list. If this is the first event on the work_list, the work
+ * element is also queued on the iwcm_wq thread.
+ *
+ * Each event holds a reference on the cm_id. Until the last posted
+ * event has been delivered and processed, the cm_id cannot be
+ * deleted.
+ *
+ * Returns:
+ * 	      0	- the event was handled.
+ *	-ENOMEM	- the event was not handled due to lack of resources.
+ */
+static int cm_event_handler(struct iw_cm_id *cm_id,
+			     struct iw_cm_event *iw_event)
+{
+	struct iwcm_work *work;
+	struct iwcm_id_private *cm_id_priv;
+	unsigned long flags;
+	int ret = 0;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	work = get_work(cm_id_priv);
+	if (!work) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	INIT_WORK(&work->work, cm_work_handler, work);
+	work->cm_id = cm_id_priv;
+	work->event = *iw_event;
+
+	if ((work->event.event == IW_CM_EVENT_CONNECT_REQUEST ||
+	     work->event.event == IW_CM_EVENT_CONNECT_REPLY) &&
+	    work->event.private_data_len) {
+		ret = copy_private_data(cm_id_priv, &work->event);
+		if (ret) {
+			put_work(work);
+			goto out;
+		}
+	}
+
+	atomic_inc(&cm_id_priv->refcount);
+	if (list_empty(&cm_id_priv->work_list)) {
+		list_add_tail(&work->list, &cm_id_priv->work_list);
+		queue_work(iwcm_wq, &work->work);
+	} else
+		list_add_tail(&work->list, &cm_id_priv->work_list);
+out:
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+	return ret;
+}
+
+static int iwcm_init_qp_init_attr(struct iwcm_id_private *cm_id_priv,
+				  struct ib_qp_attr *qp_attr,
+				  int *qp_attr_mask)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	switch (cm_id_priv->state) {
+	case IW_CM_STATE_IDLE:
+	case IW_CM_STATE_CONN_SENT:
+	case IW_CM_STATE_CONN_RECV:
+	case IW_CM_STATE_ESTABLISHED:
+		*qp_attr_mask = IB_QP_STATE | IB_QP_ACCESS_FLAGS;
+		qp_attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE |
+					   IB_ACCESS_REMOTE_WRITE|
+					   IB_ACCESS_REMOTE_READ;
+		ret = 0;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+	return ret;
+}
+
+static int iwcm_init_qp_rts_attr(struct iwcm_id_private *cm_id_priv,
+				  struct ib_qp_attr *qp_attr,
+				  int *qp_attr_mask)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&cm_id_priv->lock, flags);
+	switch (cm_id_priv->state) {
+	case IW_CM_STATE_IDLE:
+	case IW_CM_STATE_CONN_SENT:
+	case IW_CM_STATE_CONN_RECV:
+	case IW_CM_STATE_ESTABLISHED:
+		*qp_attr_mask = 0;
+		ret = 0;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+	return ret;
+}
+
+int iw_cm_init_qp_attr(struct iw_cm_id *cm_id,
+		       struct ib_qp_attr *qp_attr,
+		       int *qp_attr_mask)
+{
+	struct iwcm_id_private *cm_id_priv;
+	int ret;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	switch (qp_attr->qp_state) {
+	case IB_QPS_INIT:
+	case IB_QPS_RTR:
+		ret = iwcm_init_qp_init_attr(cm_id_priv,
+					     qp_attr, qp_attr_mask);
+		break;
+	case IB_QPS_RTS:
+		ret = iwcm_init_qp_rts_attr(cm_id_priv,
+					    qp_attr, qp_attr_mask);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	return ret;
+}
+EXPORT_SYMBOL(iw_cm_init_qp_attr);
+
+static int __init iw_cm_init(void)
+{
+	iwcm_wq = create_singlethread_workqueue("iw_cm_wq");
+	if (!iwcm_wq)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void __exit iw_cm_cleanup(void)
+{
+	destroy_workqueue(iwcm_wq);
+}
+
+module_init(iw_cm_init);
+module_exit(iw_cm_cleanup);