[PATCH v8 1/2] scsi: libsas: refactor sas_ex_to_ata() using new helper sas_ex_to_dev()

[Xingui Yang <yangxingui@huawei.com>]

Introduce sas_ex_to_dev() to return any device type attached to an
expander phy. The new helper is then used by sas_ex_to_ata() to reduce
code duplication.

Also add a defensive NULL check for ex_dev to guard against callers
passing a NULL device.

Signed-off-by: Xingui Yang <yangxingui@huawei.com>
---
 drivers/scsi/libsas/sas_expander.c | 18 +++++++++++++-----
 drivers/scsi/libsas/sas_internal.h |  1 +
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index f471ab464a78..cb9d3b748222 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -345,13 +345,15 @@ static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
 		 SAS_ADDR(phy->attached_sas_addr), type);
 }
 
-/* check if we have an existing attached ata device on this expander phy */
-struct domain_device *sas_ex_to_ata(struct domain_device *ex_dev, int phy_id)
+struct domain_device *sas_ex_to_dev(struct domain_device *ex_dev, int phy_id)
 {
-	struct ex_phy *ex_phy = &ex_dev->ex_dev.ex_phy[phy_id];
-	struct domain_device *dev;
+	struct ex_phy *ex_phy;
 	struct sas_rphy *rphy;
 
+	if (!ex_dev)
+		return NULL;
+
+	ex_phy = &ex_dev->ex_dev.ex_phy[phy_id];
 	if (!ex_phy->port)
 		return NULL;
 
@@ -359,7 +361,13 @@ struct domain_device *sas_ex_to_ata(struct domain_device *ex_dev, int phy_id)
 	if (!rphy)
 		return NULL;
 
-	dev = sas_find_dev_by_rphy(rphy);
+	return sas_find_dev_by_rphy(rphy);
+}
+
+/* check if we have an existing attached ata device on this expander phy */
+struct domain_device *sas_ex_to_ata(struct domain_device *ex_dev, int phy_id)
+{
+	struct domain_device *dev = sas_ex_to_dev(ex_dev, phy_id);
 
 	if (dev && dev_is_sata(dev))
 		return dev;
diff --git a/drivers/scsi/libsas/sas_internal.h b/drivers/scsi/libsas/sas_internal.h
index 7dce0f587149..350a70484bde 100644
--- a/drivers/scsi/libsas/sas_internal.h
+++ b/drivers/scsi/libsas/sas_internal.h
@@ -91,6 +91,7 @@ int sas_smp_get_phy_events(struct sas_phy *phy);
 
 void sas_device_set_phy(struct domain_device *dev, struct sas_port *port);
 struct domain_device *sas_find_dev_by_rphy(struct sas_rphy *rphy);
+struct domain_device *sas_ex_to_dev(struct domain_device *ex_dev, int phy_id);
 struct domain_device *sas_ex_to_ata(struct domain_device *ex_dev, int phy_id);
 int sas_ex_phy_discover(struct domain_device *dev, int single);
 int sas_get_report_phy_sata(struct domain_device *dev, int phy_id,
-- 
2.43.0