Currently a DREP is only sent in response to a DREQ if a connection
has been found matching the DREQ, and it is in the proper state. Once
a DREP is sent, the local connection moves into timewait. Duplicate
DREQs received while in this state result in re-sending the DREP.
However, it's likely that the local connection will enter and exit
timewait before the remote side times out a lost DREP and resends a DREQ.
There are a couple possible solutions to this. One is to increase how
long a connection remains in timewait, by multiplying its wait time by
max_cm_retries. This can greatly increase the timewait state before a QP
can be re-used when CM messages are not lost.
An alternative is to send a DREP in response to a DREQ, even if a local
connection is not found, which is what this patch does.
Signed-off-by: Sean Hefty <[EMAIL PROTECTED]>
---
Index: cm.c
===================================================================
--- cm.c (revision 9490)
+++ cm.c (working copy)
@@ -1900,6 +1900,32 @@ out: spin_unlock_irqrestore(&cm_id_priv-
}
EXPORT_SYMBOL(ib_send_cm_drep);
+static int cm_issue_drep(struct cm_port *port,
+ struct ib_mad_recv_wc *mad_recv_wc)
+{
+ struct ib_mad_send_buf *msg = NULL;
+ struct cm_dreq_msg *dreq_msg;
+ struct cm_drep_msg *drep_msg;
+ int ret;
+
+ ret = cm_alloc_response_msg(port, mad_recv_wc, &msg);
+ if (ret)
+ return ret;
+
+ dreq_msg = (struct cm_dreq_msg *) mad_recv_wc->recv_buf.mad;
+ drep_msg = (struct cm_drep_msg *) msg->mad;
+
+ cm_format_mad_hdr(&drep_msg->hdr, CM_DREP_ATTR_ID, dreq_msg->hdr.tid);
+ drep_msg->remote_comm_id = dreq_msg->local_comm_id;
+ drep_msg->local_comm_id = dreq_msg->remote_comm_id;
+
+ ret = ib_post_send_mad(msg, NULL);
+ if (ret)
+ cm_free_msg(msg);
+
+ return ret;
+}
+
static int cm_dreq_handler(struct cm_work *work)
{
struct cm_id_private *cm_id_priv;
@@ -1911,8 +1937,10 @@ static int cm_dreq_handler(struct cm_wor
dreq_msg = (struct cm_dreq_msg *)work->mad_recv_wc->recv_buf.mad;
cm_id_priv = cm_acquire_id(dreq_msg->remote_comm_id,
dreq_msg->local_comm_id);
- if (!cm_id_priv)
+ if (!cm_id_priv) {
+ cm_issue_drep(work->port, work->mad_recv_wc);
return -EINVAL;
+ }
work->cm_event.private_data = &dreq_msg->private_data;
_______________________________________________
openib-general mailing list
[email protected]
http://openib.org/mailman/listinfo/openib-general
To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
