scsi: storvsc: Add support for FC rport.

Included in the current storvsc driver for Hyper-V is the ability to
access luns on an FC fabric via a virtualized fiber channel adapter
exposed by the Hyper-V host. The driver also attaches to the FC
transport to allow host and port names to be published under
/sys/class/fc_host/hostX. Current customer tools running on the VM
require that these names be available in the well known standard
location under fc_host/hostX.

This patch stubs in an rport per fc_host and sets its rport role as
FC_PORT_ROLE_FCP_DUMMY_INITIATOR to indicate to the fc_transport that it
is a pseudo rport in order to scan the scsi stack via echo "- - -" >
/sys/class/scsi_host/hostX/scan.

Signed-off-by: Cathy Avery <cavery@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/storvsc_drv.c

@@ -478,6 +478,9 @@ struct storvsc_device {
 	 */
 	u64 node_name;
 	u64 port_name;
+#if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
+	struct fc_rport *rport;
+#endif
 };
 
 struct hv_host_device {
@@ -1814,19 +1817,27 @@ static int storvsc_probe(struct hv_device *device,
 		target = (device->dev_instance.b[5] << 8 |
 			 device->dev_instance.b[4]);
 		ret = scsi_add_device(host, 0, target, 0);
-		if (ret) {
-			scsi_remove_host(host);
-			goto err_out2;
-		}
+		if (ret)
+			goto err_out3;
 	}
 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
 	if (host->transportt == fc_transport_template) {
+		struct fc_rport_identifiers ids = {
+			.roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
+		};
+
 		fc_host_node_name(host) = stor_device->node_name;
 		fc_host_port_name(host) = stor_device->port_name;
+		stor_device->rport = fc_remote_port_add(host, 0, &ids);
+		if (!stor_device->rport)
+			goto err_out3;
 	}
 #endif
 	return 0;
 
+err_out3:
+	scsi_remove_host(host);
+
 err_out2:
 	/*
 	 * Once we have connected with the host, we would need to
@@ -1852,8 +1863,10 @@ static int storvsc_remove(struct hv_device *dev)
 	struct Scsi_Host *host = stor_device->host;
 
 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
-	if (host->transportt == fc_transport_template)
+	if (host->transportt == fc_transport_template) {
+		fc_remote_port_delete(stor_device->rport);
 		fc_remove_host(host);
+	}
 #endif
 	scsi_remove_host(host);
 	storvsc_dev_remove(dev);