Re: [PATCH 1/2] iWARP Connection Manager.

On Wed, 31 May 2006 13:26:52 -0500
Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx> wrote:


This patch provides the new files implementing the iWARP Connection
Manager.
---

drivers/infiniband/core/iwcm.c | 887 ++++++++++++++++++++++++++++++++++++++++
include/rdma/iw_cm.h | 254 +++++++++++
include/rdma/iw_cm_private.h | 62 +++
3 files changed, 1203 insertions(+), 0 deletions(-)

diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
new file mode 100644
index 0000000..5657ee8
--- /dev/null
+++ b/drivers/infiniband/core/iwcm.c
@@ -0,0 +1,887 @@
+/*
+ * 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.
+ *
+ */

Shouldn't all the EXPORT_SYMBOL's in this new code be EXPORT_SYMBOL_GPL
to impede use of binary vendor module's?


+#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 <rdma/iw_cm.h>
+#include <rdma/iw_cm_private.h>
+#include <rdma/ib_addr.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;
+};
+
+/*
+ * 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_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;
+ wake_up(&cm_id_priv->destroy_wait);
+ }
+ }
+
+ 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 void 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);

Please put paren's after sizeof, it is not required by C but it
is easier to read.

+
+/*
+ * 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;
+
+ 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;
+ spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+ if (cm_id_priv->qp) { /* QP could be <nul> for user-mode client */
+ if (abrupt)
+ ret = iwcm_modify_qp_err(cm_id_priv->qp);
+ else
+ ret = iwcm_modify_qp_sqd(cm_id_priv->qp);
+ /*
+ * If both sides are disconnecting the QP could
+ * already be in ERR or SQD states
+ */
+ ret = 0;
+ }
+ else
+ ret = -EINVAL;
+ break;
+ case IW_CM_STATE_LISTEN:
+ spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+ ret = -EINVAL;
+ break;
+ case IW_CM_STATE_CLOSING:
+ /* remote peer closed first */
+ case IW_CM_STATE_IDLE:
+ /* accept or connect returned !0 */
+ spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+ break;
+ case IW_CM_STATE_CONN_RECV:
+ /*
+ * App called disconnect before/without calling accept after
+ * connect_request event delivered.
+ */
+ spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+ break;
+ case IW_CM_STATE_CONN_SENT:
+ /* Can only get here if wait above fails */
+ default:
+ BUG_ON(1);
+ }

Switch statement's like this where the case does the unlock are error prone
because of the many code paths.

If you just recode slightly by using a separate return in the ESTABLISHED
case, then you can move the unlock outside of the switch.

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