[PATCH v2] libata: Simulate REPORT LUNS for ATAPI devices

["Darrick J. Wong" <djwong@us.ibm.com>]

The Quantum GoVault SATAPI removable disk device returns ATA_ERR in
response to a REPORT LUNS packet.  If this happens to an ATAPI device
that is attached to a SAS controller (this is the case with sas_ata),
the device does not load because SCSI won't touch a "SCSI device"
that won't report its LUNs.  Since most ATAPI devices don't support
multiple LUNs anyway, we might as well fake a response like we do for
ATA devices.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
---

 drivers/ata/libata-scsi.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 47ea111..5ecf260 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2833,8 +2833,13 @@ static inline int __ata_scsi_queuecmd(st
 			rc = ata_scsi_translate(dev, cmd, done, xlat_func);
 		else
 			ata_scsi_simulate(dev, cmd, done);
-	} else
-		rc = ata_scsi_translate(dev, cmd, done, atapi_xlat);
+	} else {
+		/* Simulate REPORT LUNS for ATAPI devices */
+		if (cmd->cmnd[0] == REPORT_LUNS)
+			ata_scsi_simulate(dev, cmd, done);
+		else
+			rc = ata_scsi_translate(dev, cmd, done, atapi_xlat);
+	}
 
 	return rc;
 }