IB/cm: Send DREP in response to unmatched DREQ (82a9c16a) · Commits · 戴 / test

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:

Sean Hefty <sean.hefty@intel.com> Signed-off-by:

Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/cm.c

+29 −1

Original line number	Diff line number	Diff line
		@@ -1902,6 +1902,32 @@ out: spin_unlock_irqrestore(&cm_id_priv->lock, flags);
		}
		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;
		@@ -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,
		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;

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