[SCSI] scsi_dh_alua: Attach to UNAVAILABLE/OFFLINE AAS devices

The SCSI ALUA handler currently fails to attach to devices
reporting an UNAVAILABLE/OFFLINE AAS. But given that an
UNAVAILABLE/OFFLINE AAS can transition to other states
like ACTIVE/OPTIMIZED, ACTIVE/NON-OPTIMIZED, etc. as per
SPC4, this ALUA handler behavior should be rectified so
as to attach to devices which also report an
UNAVAILABLE/OFFLINE AAS.

Signed-off-by: Martin George <marting@netapp.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/device_handler/scsi_dh_alua.c

@@ -782,7 +782,7 @@ static int alua_bus_attach(struct scsi_device *sdev)
 	h->sdev = sdev;
 
 	err = alua_initialize(sdev, h);
-	if (err != SCSI_DH_OK)
+	if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED))
 		goto failed;
 
 	if (!try_module_get(THIS_MODULE))