diff --git a/configure.d/1_block_pc.conf b/configure.d/1_block_pc.conf
deleted file mode 100644
index eb6f5fa..0000000
--- a/configure.d/1_block_pc.conf
+++ /dev/null
@@ -1,49 +0,0 @@
-#!/bin/bash
-#
-# Copyright(c) 2012-2021 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause
-#
-
-. $(dirname $3)/conf_framework
-
-check() {
-	cur_name=$(basename $2)
-	config_file_path=$1
-	if compile_module $cur_name "blk_rq_set_block_pc(NULL)"  "linux/blkdev.h"
-	then
-		echo $cur_name "1" >> $config_file_path
-	else
-		echo $cur_name "2" >> $config_file_path
-    fi
-}
-
-apply() {
-    case "$1" in
-    "1")
-		add_function "
-        static inline void cas_blk_rq_set_block_pc(struct request *rq)
-        {
-			blk_rq_set_block_pc(rq);
-        }" ;;
-    "2")
-		add_function "
-        #include <linux/blk-mq.h>
-        #include <scsi/scsi_request.h>
-        #include <scsi/scsi_cmnd.h>
-        static inline void cas_blk_rq_set_block_pc(struct request *rq)
-        {
-            struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
-
-	    struct scsi_request *req = &cmd->req;
-
-	    memset(req->__cmd, 0, sizeof(req->__cmd));
-	    req->cmd = req->__cmd;
-            req->cmd_len = BLK_MAX_CDB;
-            req->sense_len = 0;
-        }" ;;
-    *)
-        exit 1
-    esac
-}
-
-conf_run $@
diff --git a/configure.d/2_make_req.conf b/configure.d/2_make_req.conf
deleted file mode 100644
index 0b960d1..0000000
--- a/configure.d/2_make_req.conf
+++ /dev/null
@@ -1,56 +0,0 @@
-#!/bin/bash
-#
-# Copyright(c) 2012-2021 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause
-#
-
-. $(dirname $3)/conf_framework
-
-check() {
-	cur_name=$(basename $2)
-	config_file_path=$1
-	if compile_module $cur_name "blk_make_request(NULL, NULL, 0)" "linux/blkdev.h"
-	then
-        echo $cur_name "1" >> $config_file_path
-    else
-        echo $cur_name "2" >> $config_file_path
-    fi
-}
-
-apply() {
-    case "$1" in
-    "1")
-		add_function "
-	static inline struct request *cas_blk_make_request(struct request_queue *q,
-			struct bio *bio, gfp_t gfp_mask)
-	{
-		return blk_make_request(q, bio, gfp_mask);
-	}" ;;
-    "2")
-		add_function "
-	static inline struct request *cas_blk_make_request(struct request_queue *q,
-		struct bio *bio, gfp_t gfp_mask)
-	{
-		struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask);
-		if (IS_ERR(rq))
-			return rq;
-		cas_blk_rq_set_block_pc(rq);
-		rq->q = q;
-		for_each_bio(bio) {
-			struct bio *bounce_bio = bio;
-			int ret;
-			cas_blk_queue_bounce(q, &bounce_bio);
-			ret = cas_blk_rq_append_bio(rq, bounce_bio);
-			if (unlikely(ret)) {
-				blk_put_request(rq);
-				return ERR_PTR(ret);
-			}
-		}
-		return rq;
-	}" ;;
-    *)
-        exit 1
-    esac
-}
-
-conf_run $@
diff --git a/modules/cas_disk/exp_obj.c b/modules/cas_disk/exp_obj.c
index 0636242..8f4faa7 100644
--- a/modules/cas_disk/exp_obj.c
+++ b/modules/cas_disk/exp_obj.c
@@ -347,8 +347,12 @@ static int _casdsk_exp_obj_open(struct block_device *bdev, fmode_t mode)
 	mutex_lock(&dsk->openers_lock);
 
 	if (!dsk->claimed) {
-		dsk->openers++;
-		result = 0;
+		if (unlikely(dsk->openers == UINT_MAX)) {
+			result = -EBUSY;
+		} else {
+			dsk->openers++;
+			result = 0;
+		}
 	}
 
 	mutex_unlock(&dsk->openers_lock);