iwcm.c

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		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;
	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);
		goto out;
	}
	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))
		goto out;

	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);
		goto out;
	}

	/* Call the client CM handler */
	ret = cm_id->cm_handler(cm_id, iw_event);
	if (ret) {
		iw_cm_reject(cm_id, NULL, 0);
		set_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
		destroy_cm_id(cm_id);
		if (atomic_read(&cm_id_priv->refcount)==0)
			free_cm_id(cm_id_priv);
	}

out:
	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;

	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;

	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(struct work_struct *_work)
{
	struct iwcm_work *work = container_of(_work, struct iwcm_work, work);
	struct iw_cm_event levent;
	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);
		levent = work->event;
		put_work(work);
		spin_unlock_irqrestore(&cm_id_priv->lock, flags);

		ret = process_event(cm_id_priv, &levent);
		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)) {
			if (test_bit(IWCM_F_CALLBACK_DESTROY,
				     &cm_id_priv->flags)) {
				BUG_ON(!list_empty(&cm_id_priv->work_list));
				free_cm_id(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->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(&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);