scsi: libsas: add transport class for ATA devices

Now ata devices attached with sas controller do not have transport
class, so that we can not see any information of these ata devices in
/sys/class/ata_port(or ata_link or ata_device).

Add transport class for the ata devices attached with sas controller.
The /sys/class directory will show the infomation of the ata devices
as follows:

localhost:/sys/class # ls ata*
ata_device:
dev1.0  dev2.0

ata_link:
link1  link2

ata_port:
ata1  ata2

No functional change of the device scanning and io path. The ata
transport class was deleted when destroying the sas devices.
Signed-off-by: Jason Yan <yanaijie@huawei.com>
CC: Dan Williams <dan.j.williams@intel.com>
CC: Tejun Heo <tj@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/ata/libata-scsi.c

@@ -5051,6 +5051,18 @@ int ata_sas_port_init(struct ata_port *ap)
 }
 EXPORT_SYMBOL_GPL(ata_sas_port_init);
 
+int ata_sas_tport_add(struct device *parent, struct ata_port *ap)
+{
+	return ata_tport_add(parent, ap);
+}
+EXPORT_SYMBOL_GPL(ata_sas_tport_add);
+
+void ata_sas_tport_delete(struct ata_port *ap)
+{
+	ata_tport_delete(ap);
+}
+EXPORT_SYMBOL_GPL(ata_sas_tport_delete);
+
 /**
  *	ata_sas_port_destroy - Destroy a SATA port allocated by ata_sas_port_alloc
  *	@ap: SATA port to destroy

drivers/scsi/libsas/sas_ata.c

@@ -577,6 +577,11 @@ int sas_ata_init(struct domain_device *found_dev)
 		ata_sas_port_destroy(ap);
 		return rc;
 	}
+	rc = ata_sas_tport_add(found_dev->sata_dev.ata_host.dev, ap);
+	if (rc) {
+		ata_sas_port_destroy(ap);
+		return rc;
+	}
 	found_dev->sata_dev.ap = ap;
 
 	return 0;

drivers/scsi/libsas/sas_discover.c

@@ -314,6 +314,7 @@ void sas_free_device(struct kref *kref)
 		kfree(dev->ex_dev.ex_phy);
 
 	if (dev_is_sata(dev) && dev->sata_dev.ap) {
+		ata_sas_tport_delete(dev->sata_dev.ap);
 		ata_sas_port_destroy(dev->sata_dev.ap);
 		dev->sata_dev.ap = NULL;
 	}

include/linux/libata.h

@@ -1130,6 +1130,8 @@ extern void ata_sas_async_probe(struct ata_port *ap);
 extern int ata_sas_sync_probe(struct ata_port *ap);
 extern int ata_sas_port_init(struct ata_port *);
 extern int ata_sas_port_start(struct ata_port *ap);
+extern int ata_sas_tport_add(struct device *parent, struct ata_port *ap);
+extern void ata_sas_tport_delete(struct ata_port *ap);
 extern void ata_sas_port_stop(struct ata_port *ap);
 extern int ata_sas_slave_configure(struct scsi_device *, struct ata_port *);
 extern int ata_sas_queuecmd(struct scsi_cmnd *cmd, struct ata_port *ap);