Commit 82a9c16a authored by Sean Hefty's avatar Sean Hefty Committed by Roland Dreier
Browse files

IB/cm: Send DREP in response to unmatched DREQ

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.
To handle this, we send a DREP in response to a DREQ, even if a local
connection is not found.  This avoids maintaining disconnected
id's in timewait states for excessively long times, just to handle a
lost DREP.
Signed-off-by: default avatarSean Hefty <>
Signed-off-by: default avatarRoland Dreier <>
parent 8575329d
......@@ -1902,6 +1902,32 @@ out: spin_unlock_irqrestore(&cm_id_priv->lock, flags);
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)
return ret;
static int cm_dreq_handler(struct cm_work *work)
struct cm_id_private *cm_id_priv;
......@@ -1913,8 +1939,10 @@ static int cm_dreq_handler(struct cm_work *work)
dreq_msg = (struct cm_dreq_msg *)work->mad_recv_wc->recv_buf.mad;
cm_id_priv = cm_acquire_id(dreq_msg->remote_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;
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment