[PATCH v2] ata: libata-scsi: Fix get identity data failed

[Xingui Yang <yangxingui@xxxxxxxxxx>]

The function ata_get_identity() uses the helper ata_scsi_find_dev() to get
the ata_device structure of a scsi device. However, when the ata device is
managed by libsas, ata_scsi_find_dev() returns NULL, turning
ata_get_identity() into a nop and always returns -ENOMSG.

Fix this by checking whether ATA_FLAG_SAS_HOST is set for ap->flags in
ata_scsi_find_dev(), as the flag is only used in libsas. If
ATA_FLAG_SAS_HOST is set, use sas_to_ata_dev() to find associated ATA
device.

Signed-off-by: Xingui Yang <yangxingui@xxxxxxxxxx>
---
Changes to v1 
- Let ata_scsi_find_dev() return the correct value and don't keep replacing
calls to ata_scsi_find_dev().

 drivers/ata/libata-scsi.c | 12 ++++++++++--
 drivers/ata/libata.h      |  2 +-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 7bb12deab70c..aa580ea341fa 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -26,6 +26,7 @@
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_tcq.h>
 #include <scsi/scsi_transport.h>
+#include <scsi/libsas.h>
 #include <linux/libata.h>
 #include <linux/hdreg.h>
 #include <linux/uaccess.h>
@@ -2745,10 +2746,17 @@ static struct ata_device *__ata_scsi_find_dev(struct ata_port *ap,
  *	Associated ATA device, or %NULL if not found.
  */
 struct ata_device *
-ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev)
+ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev)
 {
-	struct ata_device *dev = __ata_scsi_find_dev(ap, scsidev);
+	struct ata_device *dev;
+
+	if (ap->flags & ATA_FLAG_SAS_HOST) {
+		struct domain_device *ddev = sdev_to_domain_dev(scsidev);
+
+		return sas_to_ata_dev(ddev);
+	}
 
+	dev = __ata_scsi_find_dev(ap, scsidev);
 	if (unlikely(!dev || !ata_dev_enabled(dev)))
 		return NULL;
 
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 926d0d33cd29..6d66f46da064 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -109,7 +109,7 @@ static inline void ata_acpi_bind_dev(struct ata_device *dev) {}
 
 /* libata-scsi.c */
 extern struct ata_device *ata_scsi_find_dev(struct ata_port *ap,
-					    const struct scsi_device *scsidev);
+					    struct scsi_device *scsidev);
 extern int ata_scsi_add_hosts(struct ata_host *host,
 			      const struct scsi_host_template *sht);
 extern void ata_scsi_scan_host(struct ata_port *ap, int sync);
-- 
2.17.1