diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index 2e7c136bb805..f57009b348d6 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -128,9 +128,27 @@ struct c4_inquiry {
 	u8	reserved[2];
 };
 
+#define UNIQUE_ID_LEN 16
+struct c8_inquiry {
+	u8	peripheral_info;
+	u8	page_code; /* 0xC8 */
+	u8	reserved1;
+	u8	page_len;
+	u8	page_id[4]; /* "edid" */
+	u8	reserved2[3];
+	u8	vol_uniq_id_len;
+	u8	vol_uniq_id[16];
+	u8	vol_user_label_len;
+	u8	vol_user_label[60];
+	u8	array_uniq_id_len;
+	u8	array_unique_id[UNIQUE_ID_LEN];
+	u8	array_user_label_len;
+	u8	array_user_label[60];
+	u8	lun[8];
+};
+
 struct rdac_controller {
-	u8			subsys_id[SUBSYS_ID_LEN];
-	u8			slot_id[SLOT_ID_LEN];
+	u8			array_id[UNIQUE_ID_LEN];
 	int			use_ms10;
 	struct kref		kref;
 	struct list_head	node; /* list of all controllers */
@@ -147,24 +165,6 @@ struct rdac_controller {
 	struct list_head	ms_head;
 };
 
-struct c8_inquiry {
-	u8	peripheral_info;
-	u8	page_code; /* 0xC8 */
-	u8	reserved1;
-	u8	page_len;
-	u8	page_id[4]; /* "edid" */
-	u8	reserved2[3];
-	u8	vol_uniq_id_len;
-	u8	vol_uniq_id[16];
-	u8	vol_user_label_len;
-	u8	vol_user_label[60];
-	u8	array_uniq_id_len;
-	u8	array_unique_id[16];
-	u8	array_user_label_len;
-	u8	array_user_label[60];
-	u8	lun[8];
-};
-
 struct c2_inquiry {
 	u8	peripheral_info;
 	u8	page_code;	/* 0xC2 */
@@ -369,16 +369,16 @@ static void release_controller(struct kref *kref)
 	kfree(ctlr);
 }
 
-static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id,
-						char *array_name)
+static struct rdac_controller *get_controller(int index, char *array_name,
+						u8 *array_id)
 {
 	struct rdac_controller *ctlr, *tmp;
 
 	spin_lock(&list_lock);
 
 	list_for_each_entry(tmp, &ctlr_list, node) {
-		if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0) &&
-			  (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) {
+		if ((memcmp(tmp->array_id, array_id, UNIQUE_ID_LEN) == 0) &&
+			  (tmp->index == index)) {
 			kref_get(&tmp->kref);
 			spin_unlock(&list_lock);
 			return tmp;
@@ -389,16 +389,10 @@ static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id,
 		goto done;
 
 	/* initialize fields of controller */
-	memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN);
-	memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN);
+	memcpy(ctlr->array_id, array_id, UNIQUE_ID_LEN);
+	ctlr->index = index;
 	memcpy(ctlr->array_name, array_name, ARRAY_LABEL_LEN);
 
-	/* update the controller index */
-	if (slot_id[1] == 0x31)
-		ctlr->index = 0;
-	else
-		ctlr->index = 1;
-
 	kref_init(&ctlr->kref);
 	ctlr->use_ms10 = -1;
 	ctlr->ms_queued = 0;
@@ -444,7 +438,7 @@ done:
 }
 
 static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
-			char *array_name)
+			char *array_name, u8 *array_id)
 {
 	int err, i;
 	struct c8_inquiry *inqp;
@@ -463,6 +457,8 @@ static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
 			*(array_name+i) = inqp->array_user_label[(2*i)+1];
 
 		*(array_name+ARRAY_LABEL_LEN-1) = '\0';
+		memset(array_id, 0, UNIQUE_ID_LEN);
+		memcpy(array_id, inqp->array_unique_id, inqp->array_uniq_id_len);
 	}
 	return err;
 }
@@ -504,16 +500,20 @@ static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
 }
 
 static int initialize_controller(struct scsi_device *sdev,
-				 struct rdac_dh_data *h, char *array_name)
+		struct rdac_dh_data *h, char *array_name, u8 *array_id)
 {
-	int err;
+	int err, index;
 	struct c4_inquiry *inqp;
 
 	err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h);
 	if (err == SCSI_DH_OK) {
 		inqp = &h->inq.c4;
-		h->ctlr = get_controller(inqp->subsys_id, inqp->slot_id,
-					array_name);
+		/* get the controller index */
+		if (inqp->slot_id[1] == 0x31)
+			index = 0;
+		else
+			index = 1;
+		h->ctlr = get_controller(index, array_name, array_id);
 		if (!h->ctlr)
 			err = SCSI_DH_RES_TEMP_UNAVAIL;
 	}
@@ -835,6 +835,7 @@ static int rdac_bus_attach(struct scsi_device *sdev)
 	unsigned long flags;
 	int err;
 	char array_name[ARRAY_LABEL_LEN];
+	char array_id[UNIQUE_ID_LEN];
 
 	scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
 			       + sizeof(*h) , GFP_KERNEL);
@@ -849,11 +850,11 @@ static int rdac_bus_attach(struct scsi_device *sdev)
 	h->lun = UNINITIALIZED_LUN;
 	h->state = RDAC_STATE_ACTIVE;
 
-	err = get_lun_info(sdev, h, array_name);
+	err = get_lun_info(sdev, h, array_name, array_id);
 	if (err != SCSI_DH_OK)
 		goto failed;
 
-	err = initialize_controller(sdev, h, array_name);
+	err = initialize_controller(sdev, h, array_name, array_id);
 	if (err != SCSI_DH_OK)
 		goto failed;