[SCSI] dh_rdac: Associate HBA and storage in rdac_controller to support partitions in storage

rdac hardware handler assumes that there is one-to-one relation ship
between the host and the controller w.r.t lun. IOW, it does not
support "multiple storage partitions" within a storage.

Example:
HBA1 and HBA2 see lun 0 and 1 in storage A (1)
HBA3 and HBA4 see lun 0 and 1 in storage A (2)
HBA5 and HBA6 see lun 0 and 1 in storage A (3)

luns 0 and 1 in (1), (2) and (3) are totally different.

But, rdac handler treats the lun 0s (and lun 1s) as the same when
sending a mode select to the controller, which is wrong.

This patch makes the rdac hardware handler associate HBA and the
storage w.r.t lun (and not the host itself).

Signed-off-by: Chandra Seetharaman <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/device_handler/scsi_dh_rdac.c

···
 	} mode_select;
 	u8	index;
 	u8	array_name[ARRAY_LABEL_LEN];
+	struct Scsi_Host	*host;
 	spinlock_t		ms_lock;
 	int			ms_queued;
 	struct work_struct	ms_work;
···
 }
 
 static struct rdac_controller *get_controller(int index, char *array_name,
-						u8 *array_id)
+			u8 *array_id, struct scsi_device *sdev)
 {
 	struct rdac_controller *ctlr, *tmp;
 
···
 
 	list_for_each_entry(tmp, &ctlr_list, node) {
 		if ((memcmp(tmp->array_id, array_id, UNIQUE_ID_LEN) == 0) &&
-			  (tmp->index == index)) {
+			  (tmp->index == index) &&
+			  (tmp->host == sdev->host)) {
 			kref_get(&tmp->kref);
 			spin_unlock(&list_lock);
 			return tmp;
···
 	/* initialize fields of controller */
 	memcpy(ctlr->array_id, array_id, UNIQUE_ID_LEN);
 	ctlr->index = index;
+	ctlr->host = sdev->host;
 	memcpy(ctlr->array_name, array_name, ARRAY_LABEL_LEN);
 
 	kref_init(&ctlr->kref);
···
 			index = 0;
 		else
 			index = 1;
-		h->ctlr = get_controller(index, array_name, array_id);
+		h->ctlr = get_controller(index, array_name, array_id, sdev);
 		if (!h->ctlr)
 			err = SCSI_DH_RES_TEMP_UNAVAIL;
 	}