IB/mad: Split IB SMI handling from MAD Recv handler

Make a helper function to process Directed Route SMPs to be called by the IB
MAD Recv Handler, ib_mad_recv_done_handler.

This cleans up the MAD receive handler code a bit and allows for us to better
share the SMP processing code between IB and OPA SMPs.

IB and OPA SMPs share the same processing algorithm but have different header
formats and permissive LID detection.  Therefore this and subsequent patches
split the common processing code from the IB specific code in anticipation of
sharing those algorithms with the OPA code.
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/mad.c

@@ -1924,6 +1924,52 @@ static void ib_mad_complete_recv(struct ib_mad_agent_private *mad_agent_priv,
 	}
 }
 
+static enum smi_action handle_ib_smi(const struct ib_mad_port_private *port_priv,
+				     const struct ib_mad_qp_info *qp_info,
+				     const struct ib_wc *wc,
+				     int port_num,
+				     struct ib_mad_private *recv,
+				     struct ib_mad_private *response)
+{
+	enum smi_forward_action retsmi;
+
+	if (smi_handle_dr_smp_recv(&recv->mad.smp,
+				   port_priv->device->node_type,
+				   port_num,
+				   port_priv->device->phys_port_cnt) ==
+				   IB_SMI_DISCARD)
+		return IB_SMI_DISCARD;
+
+	retsmi = smi_check_forward_dr_smp(&recv->mad.smp);
+	if (retsmi == IB_SMI_LOCAL)
+		return IB_SMI_HANDLE;
+
+	if (retsmi == IB_SMI_SEND) { /* don't forward */
+		if (smi_handle_dr_smp_send(&recv->mad.smp,
+					   port_priv->device->node_type,
+					   port_num) == IB_SMI_DISCARD)
+			return IB_SMI_DISCARD;
+
+		if (smi_check_local_smp(&recv->mad.smp, port_priv->device) == IB_SMI_DISCARD)
+			return IB_SMI_DISCARD;
+	} else if (port_priv->device->node_type == RDMA_NODE_IB_SWITCH) {
+		/* forward case for switches */
+		memcpy(response, recv, sizeof(*response));
+		response->header.recv_wc.wc = &response->header.wc;
+		response->header.recv_wc.recv_buf.mad = &response->mad.mad;
+		response->header.recv_wc.recv_buf.grh = &response->grh;
+
+		agent_send_response(&response->mad.mad,
+				    &response->grh, wc,
+				    port_priv->device,
+				    smi_get_fwd_port(&recv->mad.smp),
+				    qp_info->qp->qp_num);
+
+		return IB_SMI_DISCARD;
+	}
+	return IB_SMI_HANDLE;
+}
+
 static bool generate_unmatched_resp(struct ib_mad_private *recv,
 				    struct ib_mad_private *response)
 {
@@ -1996,45 +2042,12 @@ static void ib_mad_recv_done_handler(struct ib_mad_port_private *port_priv,
 
 	if (recv->mad.mad.mad_hdr.mgmt_class ==
 	    IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) {
-		enum smi_forward_action retsmi;
-
-		if (smi_handle_dr_smp_recv(&recv->mad.smp,
-					   port_priv->device->node_type,
-					   port_num,
-					   port_priv->device->phys_port_cnt) ==
-					   IB_SMI_DISCARD)
+		if (handle_ib_smi(port_priv, qp_info, wc, port_num, recv,
+				  response)
+		    == IB_SMI_DISCARD)
 			goto out;
-
-		retsmi = smi_check_forward_dr_smp(&recv->mad.smp);
-		if (retsmi == IB_SMI_LOCAL)
-			goto local;
-
-		if (retsmi == IB_SMI_SEND) { /* don't forward */
-			if (smi_handle_dr_smp_send(&recv->mad.smp,
-						   port_priv->device->node_type,
-						   port_num) == IB_SMI_DISCARD)
-				goto out;
-
-			if (smi_check_local_smp(&recv->mad.smp, port_priv->device) == IB_SMI_DISCARD)
-				goto out;
-		} else if (port_priv->device->node_type == RDMA_NODE_IB_SWITCH) {
-			/* forward case for switches */
-			memcpy(response, recv, sizeof(*response));
-			response->header.recv_wc.wc = &response->header.wc;
-			response->header.recv_wc.recv_buf.mad = &response->mad.mad;
-			response->header.recv_wc.recv_buf.grh = &response->grh;
-
-			agent_send_response(&response->mad.mad,
-					    &response->grh, wc,
-					    port_priv->device,
-					    smi_get_fwd_port(&recv->mad.smp),
-					    qp_info->qp->qp_num);
-
-			goto out;
-		}
 	}
 
-local:
 	/* Give driver "right of first refusal" on incoming MAD */
 	if (port_priv->device->process_mad) {
 		ret = port_priv->device->process_mad(port_priv->device, 0,