scsi_dh_alua: improved logging

Issue different logging messages if ALUA is not supported
or the TPGS setting is invalid.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

BugLink: http://bugs.launchpad.net/bugs/1567602

(cherry-picked from commit 6cc05d45)
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/scsi/device_handler/scsi_dh_alua.c

@@ -310,12 +310,18 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
 		sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
 			    ALUA_DH_NAME);
 		break;
-	default:
-		h->tpgs = TPGS_MODE_NONE;
+	case TPGS_MODE_NONE:
 		sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
 			    ALUA_DH_NAME);
 		err = SCSI_DH_DEV_UNSUPP;
 		break;
+	default:
+		sdev_printk(KERN_INFO, sdev,
+			    "%s: unsupported TPGS setting %d\n",
+			    ALUA_DH_NAME, h->tpgs);
+		h->tpgs = TPGS_MODE_NONE;
+		err = SCSI_DH_DEV_UNSUPP;
+		break;
 	}
 
 	return err;