From fbc3906576475f4b87afdfe3e38dd5b53ae869ae Mon Sep 17 00:00:00 2001
From: Robert Baldyga <robert.baldyga@intel.com>
Date: Mon, 17 May 2021 17:02:59 +0200
Subject: [PATCH 1/9] Replace removed kernel API function with new one

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 modules/cas_cache/volume/vol_block_dev_top.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/cas_cache/volume/vol_block_dev_top.c b/modules/cas_cache/volume/vol_block_dev_top.c
index ba88a02..1820827 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.c
+++ b/modules/cas_cache/volume/vol_block_dev_top.c
@@ -627,7 +627,7 @@ static int _blockdev_set_geometry(struct casdsk_disk *dsk, void *private)
 		return -KCAS_ERR_UNALIGNED;
 	}
 
-	blk_queue_stack_limits(exp_q, core_q);
+	blk_stack_limits(&exp_q->limits, &core_q->limits, 0);
 
 	/* We don't want to receive splitted requests*/
 	CAS_SET_QUEUE_CHUNK_SECTORS(exp_q, 0);

From 7343cb55fa70d5fae3c491a17969fc1ed6b141b6 Mon Sep 17 00:00:00 2001
From: Robert Baldyga <robert.baldyga@intel.com>
Date: Mon, 17 May 2021 17:02:38 +0200
Subject: [PATCH 2/9] Handle all io on bio handler

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 configure.d/1_bio_gendisk.conf                |  34 ++
 configure.d/1_flush_flag.conf                 |  32 +-
 configure.d/1_make_request.conf               |  12 +-
 configure.d/1_req_flush.conf                  |  40 +++
 configure.d/1_set_submit_bio.conf             |  31 ++
 configure.d/2_queue_write.conf                |   4 +-
 modules/cas_cache/volume/obj_blk.h            |   7 +-
 .../cas_cache/volume/vol_atomic_dev_bottom.c  |  13 +-
 .../cas_cache/volume/vol_block_dev_bottom.c   |   5 +-
 modules/cas_cache/volume/vol_block_dev_top.c  | 328 +++++++++++-------
 modules/cas_disk/cas_disk.h                   |  12 +-
 modules/cas_disk/cas_disk_defs.h              |   1 +
 modules/cas_disk/exp_obj.c                    |  33 +-
 modules/cas_disk/exp_obj.h                    |   2 -
 14 files changed, 374 insertions(+), 180 deletions(-)
 create mode 100644 configure.d/1_bio_gendisk.conf
 create mode 100644 configure.d/1_req_flush.conf
 create mode 100644 configure.d/1_set_submit_bio.conf

diff --git a/configure.d/1_bio_gendisk.conf b/configure.d/1_bio_gendisk.conf
new file mode 100644
index 0000000..475b43e
--- /dev/null
+++ b/configure.d/1_bio_gendisk.conf
@@ -0,0 +1,34 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+check() {
+	cur_name=$(basename $2)
+	config_file_path=$1
+	if compile_module $cur_name "struct bio *bio; bio->bi_disk;" "linux/blk_types.h"
+	then
+		echo $cur_name "1" >> $config_file_path
+	elif compile_module $cur_name "struct bio *bio; bio->bi_bdev;" "linux/blk_types.h"
+    then
+		echo $cur_name "2" >> $config_file_path
+	else
+		echo $cur_name "X" >> $config_file_path
+    fi
+}
+
+apply() {
+    case "$1" in
+    "1")
+	    add_define "CAS_BIO_GET_GENDISK(bio) (bio->bi_disk)" ;;
+    "2")
+	    add_define "CAS_BIO_GET_GENDISK(bio) (bio->bi_bdev->bd_disk)" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/1_flush_flag.conf b/configure.d/1_flush_flag.conf
index 0648fc9..5dd9d26 100644
--- a/configure.d/1_flush_flag.conf
+++ b/configure.d/1_flush_flag.conf
@@ -9,12 +9,15 @@
 check() {
 	cur_name=$(basename $2)
 	config_file_path=$1
-	if compile_module $cur_name "REQ_PREFLUSH" "linux/blk_types.h"
+    if compile_module $cur_name "BIO_FLUSH" "linux/bio.h"
 	then
 		echo $cur_name "1" >> $config_file_path
 	elif compile_module $cur_name "REQ_FLUSH" "linux/blk_types.h"
 	then
 		echo $cur_name "2" >> $config_file_path
+	elif compile_module $cur_name "REQ_PREFLUSH" "linux/blk_types.h"
+	then
+		echo $cur_name "3" >> $config_file_path
     else
         echo $cur_name "X" >> $config_file_path
     fi
@@ -23,15 +26,26 @@ check() {
 apply() {
     case "$1" in
     "1")
-		add_define "CAS_REQ_FLUSH \\
-			REQ_PREFLUSH"
-		add_define "CAS_FLUSH_SUPPORTED \\
-			1" ;;
+        add_define "CAS_IS_SET_FLUSH(flags) \\
+            ((flags) & BIO_FLUSH)"
+        add_define "CAS_SET_FLUSH(flags) \\
+            ((flags) | BIO_FLUSH)"
+        add_define "CAS_CLEAR_FLUSH(flags) \\
+            ((flags) & ~BIO_FLUSH)" ;;
     "2")
-		add_define "CAS_REQ_FLUSH \\
-			REQ_FLUSH"
-		add_define "CAS_FLUSH_SUPPORTED \\
-			1" ;;
+        add_define "CAS_IS_SET_FLUSH(flags) \\
+            ((flags) & REQ_FLUSH)"
+        add_define "CAS_SET_FLUSH(flags) \\
+            ((flags) | REQ_FLUSH)"
+        add_define "CAS_CLEAR_FLUSH(flags) \\
+            ((flags) & ~REQ_FLUSH)" ;;
+    "3")
+        add_define "CAS_IS_SET_FLUSH(flags) \\
+            ((flags) & REQ_PREFLUSH)"
+        add_define "CAS_SET_FLUSH(flags) \\
+            ((flags) | REQ_PREFLUSH)"
+        add_define "CAS_CLEAR_FLUSH(flags) \\
+            ((flags) & ~REQ_PREFLUSH)" ;;
     *)
         exit 1
     esac
diff --git a/configure.d/1_make_request.conf b/configure.d/1_make_request.conf
index ded54f5..b1f3f6d 100644
--- a/configure.d/1_make_request.conf
+++ b/configure.d/1_make_request.conf
@@ -12,8 +12,11 @@ check() {
     if compile_module $cur_name "blk_queue_make_request" "linux/blkdev.h"
     then
         echo $cur_name "1" >> $config_file_path
-    else
+    elif compile_module $cur_name "struct request_queue *q; q->make_request_fn;" "linux/blkdev.h"
+    then
         echo $cur_name "2" >> $config_file_path
+    else
+        echo $cur_name "3" >> $config_file_path
     fi
 }
 
@@ -33,6 +36,13 @@ apply() {
         {
             q->make_request_fn = mfn;
         }" ;;
+    "3")
+		add_define "make_request_fn void"
+        add_function "
+        static inline void cas_blk_queue_make_request(struct request_queue *q,
+                make_request_fn *mfn)
+        {
+        }" ;;
     *)
         exit 1
     esac
diff --git a/configure.d/1_req_flush.conf b/configure.d/1_req_flush.conf
new file mode 100644
index 0000000..0648fc9
--- /dev/null
+++ b/configure.d/1_req_flush.conf
@@ -0,0 +1,40 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+check() {
+	cur_name=$(basename $2)
+	config_file_path=$1
+	if compile_module $cur_name "REQ_PREFLUSH" "linux/blk_types.h"
+	then
+		echo $cur_name "1" >> $config_file_path
+	elif compile_module $cur_name "REQ_FLUSH" "linux/blk_types.h"
+	then
+		echo $cur_name "2" >> $config_file_path
+    else
+        echo $cur_name "X" >> $config_file_path
+    fi
+}
+
+apply() {
+    case "$1" in
+    "1")
+		add_define "CAS_REQ_FLUSH \\
+			REQ_PREFLUSH"
+		add_define "CAS_FLUSH_SUPPORTED \\
+			1" ;;
+    "2")
+		add_define "CAS_REQ_FLUSH \\
+			REQ_FLUSH"
+		add_define "CAS_FLUSH_SUPPORTED \\
+			1" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/1_set_submit_bio.conf b/configure.d/1_set_submit_bio.conf
new file mode 100644
index 0000000..8938c54
--- /dev/null
+++ b/configure.d/1_set_submit_bio.conf
@@ -0,0 +1,31 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+check() {
+    cur_name=$(basename $2)
+    config_file_path=$1
+    if compile_module $cur_name "struct block_device_operations *ops; ops->submit_bio;" "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_define "CAS_SET_SUBMIT_BIO(_fn) .submit_bio = _fn," ;;
+    "2")
+		add_define "CAS_SET_SUBMIT_BIO(_fn)" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/2_queue_write.conf b/configure.d/2_queue_write.conf
index 98e620b..64908fd 100644
--- a/configure.d/2_queue_write.conf
+++ b/configure.d/2_queue_write.conf
@@ -35,7 +35,7 @@ apply() {
 	}" ;;
     "2")
 		add_define "CAS_CHECK_QUEUE_FLUSH(q) \\
-			((q)->flush_flags & CAS_REQ_FLUSH)"
+			CAS_IS_SET_FLUSH((q)->flush_flags)"
 		add_define "CAS_CHECK_QUEUE_FUA(q) \\
 			((q)->flush_flags & REQ_FUA)"
 		add_function "static inline void cas_set_queue_flush_fua(struct request_queue *q,
@@ -43,7 +43,7 @@ apply() {
 	{
 		unsigned int flags = 0;
 		if (flush)
-			flags |= CAS_REQ_FLUSH;
+			flags = CAS_SET_FLUSH(flags);
 		if (fua)
 			flags |= REQ_FUA;
 		if (flags)
diff --git a/modules/cas_cache/volume/obj_blk.h b/modules/cas_cache/volume/obj_blk.h
index a9af2f7..00d3a38 100644
--- a/modules/cas_cache/volume/obj_blk.h
+++ b/modules/cas_cache/volume/obj_blk.h
@@ -31,8 +31,11 @@ struct bd_object {
 	atomic64_t pending_rqs;
 		/*!< This fields describes in flight IO requests */
 
-	struct workqueue_struct *workqueue;
-		/*< Workqueue for internally trigerred I/O */
+	struct workqueue_struct *btm_wq;
+		/*< Workqueue for I/O internally trigerred in bottom vol */
+
+	struct workqueue_struct *expobj_wq;
+		/*< Workqueue for I/O handled by top vol */
 };
 
 static inline struct bd_object *bd_object(ocf_volume_t vol)
diff --git a/modules/cas_cache/volume/vol_atomic_dev_bottom.c b/modules/cas_cache/volume/vol_atomic_dev_bottom.c
index 376ca91..82046a5 100644
--- a/modules/cas_cache/volume/vol_atomic_dev_bottom.c
+++ b/modules/cas_cache/volume/vol_atomic_dev_bottom.c
@@ -903,8 +903,7 @@ void cas_atomic_submit_io(struct ocf_io *io)
 {
 	CAS_DEBUG_TRACE();
 
-	if (!CAS_IS_WRITE_FLUSH_FUA(io->flags) &&
-			CAS_IS_WRITE_FLUSH(io->flags)) {
+	if (CAS_IS_SET_FLUSH(io->flags)) {
 		/* FLUSH */
 		cas_atomic_submit_flush(io);
 		return;
@@ -953,8 +952,8 @@ void cas_atomic_close_object(ocf_volume_t volume)
 {
 	struct bd_object *bdobj = bd_object(volume);
 
-	if(bdobj->workqueue)
-		destroy_workqueue(bdobj->workqueue);
+	if(bdobj->btm_wq)
+		destroy_workqueue(bdobj->btm_wq);
 
 	block_dev_close_object(volume);
 }
@@ -976,8 +975,8 @@ int cas_atomic_open_object(ocf_volume_t volume, void *volume_params)
 	memcpy(&bdobj->atomic_params, volume_params,
 			sizeof(bdobj->atomic_params));
 
-	bdobj->workqueue = create_workqueue("CAS_AT_ZER");
-	if (!bdobj->workqueue) {
+	bdobj->btm_wq = create_workqueue("CAS_AT_ZER");
+	if (!bdobj->btm_wq) {
 		cas_atomic_close_object(volume);
 		result = -ENOMEM;
 		goto end;
@@ -1036,7 +1035,7 @@ static void _cas_atomic_write_zeroes_step_cmpl(struct ocf_io *io, int error)
 		_cas_atomic_write_zeroes_end(ctx, error);
 	} else {
 		/* submit next IO from work context */
-		queue_work(bdobj->workqueue, &ctx->cmpl_work);
+		queue_work(bdobj->btm_wq, &ctx->cmpl_work);
 	}
 }
 
diff --git a/modules/cas_cache/volume/vol_block_dev_bottom.c b/modules/cas_cache/volume/vol_block_dev_bottom.c
index 7109bda..dae8728 100644
--- a/modules/cas_cache/volume/vol_block_dev_bottom.c
+++ b/modules/cas_cache/volume/vol_block_dev_bottom.c
@@ -267,7 +267,7 @@ static void block_dev_submit_flush(struct ocf_io *io)
 	bio->bi_private = io;
 
 	atomic_inc(&blkio->rq_remaning);
-	cas_submit_bio(CAS_WRITE_FLUSH, bio);
+	cas_submit_bio(CAS_SET_FLUSH(0), bio);
 
 out:
 	cas_bd_io_end(io, blkio->error);
@@ -412,8 +412,7 @@ static void block_dev_submit_io(struct ocf_io *io)
 	uint32_t bytes = io->bytes;
 	int dir = io->dir;
 
-	if (!CAS_IS_WRITE_FLUSH_FUA(io->flags) &&
-			CAS_IS_WRITE_FLUSH(io->flags)) {
+	if (CAS_IS_SET_FLUSH(io->flags)) {
 		CAS_DEBUG_MSG("Flush request");
 		/* It is flush requests handle it */
 		block_dev_submit_flush(io);
diff --git a/modules/cas_cache/volume/vol_block_dev_top.c b/modules/cas_cache/volume/vol_block_dev_top.c
index 1820827..01af060 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.c
+++ b/modules/cas_cache/volume/vol_block_dev_top.c
@@ -73,34 +73,13 @@ static inline void _blockdev_end_io_acct(struct bio *bio,
 	cas_generic_end_io_acct(gd->queue, bio, &gd->part0, start_time);
 }
 
-void block_dev_start_bio_fast(struct ocf_io *io)
+void block_dev_start_bio(struct ocf_io *io)
 {
 	struct blk_data *data = ocf_io_get_data(io);
 	struct bio *bio = data->master_io_req;
 
 	data->start_time = _blockdev_start_io_acct(bio);
 }
-
-void block_dev_complete_bio_fast(struct ocf_io *io, int error)
-{
-	struct blk_data *data = ocf_io_get_data(io);
-	struct bio *bio = data->master_io_req;
-
-	_blockdev_end_io_acct(bio, data->start_time);
-
-	CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(error));
-	ocf_io_put(io);
-	cas_free_blk_data(data);
-}
-
-void block_dev_complete_bio_discard(struct ocf_io *io, int error)
-{
-	struct bio *bio = io->priv1;
-
-	CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(error));
-	ocf_io_put(io);
-}
-
 void block_dev_complete_rq(struct ocf_io *io, int error)
 
 {
@@ -507,23 +486,6 @@ static inline int _blkdev_can_hndl_bio(struct bio *bio)
 	return 0;
 }
 
-static inline bool _blkdev_is_flush_fua_bio(struct bio *bio)
-{
-	if (CAS_IS_WRITE_FLUSH_FUA(CAS_BIO_OP_FLAGS(bio))) {
-		/* FLUSH and FUA */
-		return true;
-	} else if (CAS_IS_WRITE_FUA(CAS_BIO_OP_FLAGS(bio))) {
-		/* FUA */
-		return true;
-	} else if (CAS_IS_WRITE_FLUSH(CAS_BIO_OP_FLAGS(bio))) {
-		/* FLUSH */
-		return true;
-
-	}
-
-	return false;
-}
-
 void _blockdev_set_exported_object_flush_fua(ocf_core_t core)
 {
 #ifdef CAS_FLUSH_SUPPORTED
@@ -670,10 +632,125 @@ static void _blockdev_pending_req_dec(struct casdsk_disk *dsk, void *private)
 	atomic64_dec(&bvol->pending_rqs);
 }
 
-static void _blockdev_make_request_discard(struct casdsk_disk *dsk,
-		struct request_queue *q, struct bio *bio, void *private)
+struct defer_bio_context {
+	struct work_struct io_work;
+	void (*cb)(ocf_core_t core, struct bio *bio);
+	ocf_core_t core;
+	struct bio *bio;
+};
+
+static void _blockdev_defer_bio_work(struct work_struct *work)
+{
+	struct defer_bio_context *context;
+
+	context = container_of(work, struct defer_bio_context, io_work);
+	context->cb(context->core, context->bio);
+	kfree(context);
+}
+
+static void _blockdev_defer_bio(ocf_core_t core, struct bio *bio,
+	void (*cb)(ocf_core_t core, struct bio *bio))
+{
+	struct defer_bio_context *context;
+	ocf_volume_t volume = ocf_core_get_volume(core);
+	struct bd_object *bvol = bd_object(volume);
+
+	BUG_ON(!bvol->expobj_wq);
+
+	context = kmalloc(sizeof(*context), GFP_ATOMIC);
+	if (!context) {
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio),
+			CAS_ERRNO_TO_BLK_STS(-ENOMEM));
+		return;
+	}
+
+	context->cb = cb;
+	context->bio = bio;
+	context->core = core;
+	INIT_WORK(&context->io_work, _blockdev_defer_bio_work);
+	queue_work(bvol->expobj_wq, &context->io_work);
+}
+
+static void block_dev_complete_data(struct ocf_io *io, int error)
+{
+	struct blk_data *data = ocf_io_get_data(io);
+	struct bio *bio = data->master_io_req;
+
+	_blockdev_end_io_acct(bio, data->start_time);
+
+	CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(error));
+	ocf_io_put(io);
+	cas_free_blk_data(data);
+}
+
+static void _blockdev_handle_data(ocf_core_t core, struct bio *bio)
+{
+	ocf_cache_t cache;
+	struct cache_priv *cache_priv;
+	struct ocf_io *io;
+	struct blk_data *data;
+	uint64_t flags = CAS_BIO_OP_FLAGS(bio);
+	int ret;
+
+	cache = ocf_core_get_cache(core);
+	cache_priv = ocf_cache_get_priv(cache);
+
+	if (unlikely(CAS_BIO_BISIZE(bio) == 0)) {
+		CAS_PRINT_RL(KERN_ERR
+			"Not able to handle empty BIO, flags = "
+			CAS_BIO_OP_FLAGS_FORMAT "\n",  CAS_BIO_OP_FLAGS(bio));
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EINVAL));
+		return;
+	}
+
+	data = cas_alloc_blk_data(bio_segments(bio), GFP_NOIO);
+	if (!data) {
+		CAS_PRINT_RL(KERN_CRIT "BIO data vector allocation error\n");
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-ENOMEM));
+		return;
+	}
+
+	_blockdev_set_bio_data(data, bio);
+
+	data->master_io_req = bio;
+
+	io = ocf_core_new_io(core, cache_priv->io_queues[smp_processor_id()],
+			CAS_BIO_BISECTOR(bio) << SECTOR_SHIFT,
+			CAS_BIO_BISIZE(bio), (bio_data_dir(bio) == READ) ?
+					OCF_READ : OCF_WRITE,
+			cas_cls_classify(cache, bio), CAS_CLEAR_FLUSH(flags));
+
+	if (!io) {
+		printk(KERN_CRIT "Out of memory. Ending IO processing.\n");
+		cas_free_blk_data(data);
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-ENOMEM));
+		return;
+	}
+
+	ret = ocf_io_set_data(io, data, 0);
+	if (ret < 0) {
+		ocf_io_put(io);
+		cas_free_blk_data(data);
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EINVAL));
+		return;
+	}
+
+	ocf_io_set_cmpl(io, NULL, NULL, block_dev_complete_data);
+	ocf_io_set_start(io, block_dev_start_bio);
+
+	ocf_core_submit_io(io);
+}
+
+static void block_dev_complete_discard(struct ocf_io *io, int error)
+{
+	struct bio *bio = io->priv1;
+
+	CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(error));
+	ocf_io_put(io);
+}
+
+static void _blockdev_handle_discard(ocf_core_t core, struct bio *bio)
 {
-	ocf_core_t core = private;
 	ocf_cache_t cache = ocf_core_get_cache(core);
 	struct cache_priv *cache_priv = ocf_cache_get_priv(cache);
 	struct ocf_io *io;
@@ -689,105 +766,89 @@ static void _blockdev_make_request_discard(struct casdsk_disk *dsk,
 		return;
 	}
 
-	ocf_io_set_cmpl(io, bio, NULL, block_dev_complete_bio_discard);
+	ocf_io_set_cmpl(io, bio, NULL, block_dev_complete_discard);
 
 	ocf_core_submit_discard(io);
 }
 
-static int _blockdev_make_request_fast(struct casdsk_disk *dsk,
-		struct request_queue *q, struct bio *bio, void *private)
+static void _blockdev_handle_bio_noflush(ocf_core_t core, struct bio *bio)
 {
-	ocf_core_t core;
-	ocf_cache_t cache;
-	struct cache_priv *cache_priv;
-	struct ocf_io *io;
-	struct blk_data *data;
-	int ret;
+	if (CAS_IS_DISCARD(bio))
+		_blockdev_handle_discard(core, bio);
+	else
+		_blockdev_handle_data(core, bio);
+}
 
-	BUG_ON(!private);
-	core = private;
-	cache = ocf_core_get_cache(core);
-	cache_priv = ocf_cache_get_priv(cache);
+static void block_dev_complete_flush(struct ocf_io *io, int error)
+{
+	struct bio *bio = io->priv1;
+	ocf_core_t core = io->priv2;
+
+	ocf_io_put(io);
+
+	if (CAS_BIO_BISIZE(bio) == 0 || error) {
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio),
+				CAS_ERRNO_TO_BLK_STS(error));
+		return;
+	}
 
 	if (in_interrupt())
-		return CASDSK_BIO_NOT_HANDLED;
+		_blockdev_defer_bio(core, bio, _blockdev_handle_bio_noflush);
+	else
+		_blockdev_handle_bio_noflush(core, bio);
+}
 
-	if (_blkdev_can_hndl_bio(bio))
-		return CASDSK_BIO_HANDLED;
-
-	if (_blkdev_is_flush_fua_bio(bio))
-		return CASDSK_BIO_NOT_HANDLED;
-
-	if (CAS_IS_DISCARD(bio)) {
-		_blockdev_make_request_discard(dsk, q, bio, private);
-		return CASDSK_BIO_HANDLED;
-	}
-
-	if (unlikely(CAS_BIO_BISIZE(bio) == 0)) {
-		CAS_PRINT_RL(KERN_ERR
-			"Not able to handle empty BIO, flags = "
-			CAS_BIO_OP_FLAGS_FORMAT "\n",  CAS_BIO_OP_FLAGS(bio));
-		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EINVAL));
-		return CASDSK_BIO_HANDLED;
-	}
-
-	data = cas_alloc_blk_data(bio_segments(bio), GFP_NOIO);
-	if (!data) {
-		CAS_PRINT_RL(KERN_CRIT "BIO data vector allocation error\n");
-		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-ENOMEM));
-		return CASDSK_BIO_HANDLED;
-	}
-
-	_blockdev_set_bio_data(data, bio);
-
-	data->master_io_req = bio;
+static void _blkdev_handle_flush(ocf_core_t core, struct bio *bio)
+{
+	struct ocf_io *io;
+	ocf_cache_t cache = ocf_core_get_cache(core);
+	struct cache_priv *cache_priv = ocf_cache_get_priv(cache);
 
 	io = ocf_core_new_io(core, cache_priv->io_queues[smp_processor_id()],
-			CAS_BIO_BISECTOR(bio) << SECTOR_SHIFT,
-			CAS_BIO_BISIZE(bio), (bio_data_dir(bio) == READ) ?
-					OCF_READ : OCF_WRITE,
-			cas_cls_classify(cache, bio), 0);
-
+			0, 0, OCF_WRITE, 0, CAS_SET_FLUSH(0));
 	if (!io) {
-		printk(KERN_CRIT "Out of memory. Ending IO processing.\n");
-		cas_free_blk_data(data);
+		CAS_PRINT_RL(KERN_CRIT
+			"Out of memory. Ending IO processing.\n");
 		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-ENOMEM));
-		return CASDSK_BIO_HANDLED;
+		return;
 	}
 
-	ret = ocf_io_set_data(io, data, 0);
-	if (ret < 0) {
-		ocf_io_put(io);
-		cas_free_blk_data(data);
-		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EINVAL));
-		return CASDSK_BIO_HANDLED;
+	ocf_io_set_cmpl(io, bio, core, block_dev_complete_flush);
+
+	ocf_core_submit_flush(io);
+}
+
+static void _blockdev_handle_bio(ocf_core_t core, struct bio *bio)
+{
+	if (CAS_IS_SET_FLUSH(CAS_BIO_OP_FLAGS(bio)))
+		_blkdev_handle_flush(core, bio);
+	else
+		_blockdev_handle_bio_noflush(core, bio);
+}
+
+static void _blockdev_submit_bio(struct casdsk_disk *dsk,
+		struct bio *bio, void *private)
+{
+	ocf_core_t core = private;
+
+	BUG_ON(!core);
+
+	if (_blkdev_can_hndl_bio(bio)) {
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio),
+				CAS_ERRNO_TO_BLK_STS(-ENOTSUPP));
+		return;
 	}
 
-	ocf_io_set_cmpl(io, NULL, NULL, block_dev_complete_bio_fast);
-	ocf_io_set_start(io, block_dev_start_bio_fast);
-
-	ret = ocf_core_submit_io_fast(io);
-	if (ret < 0)
-		goto err;
-
-	return CASDSK_BIO_HANDLED;
-
-err:
-	/*
-	 * - Not able to processed fast path for this BIO,
-	 * - Cleanup current request
-	 * - Put it to the IO scheduler
-	 */
-	ocf_io_put(io);
-	cas_free_blk_data(data);
-
-	return CASDSK_BIO_NOT_HANDLED;
+	if (in_interrupt())
+		_blockdev_defer_bio(core, bio, _blockdev_handle_bio);
+	else
+		_blockdev_handle_bio(core, bio);
 }
 
 static struct casdsk_exp_obj_ops _blockdev_exp_obj_ops = {
 	.set_geometry = _blockdev_set_geometry,
-	.make_request_fn = _blockdev_make_request_fast,
 	.queue_rq_fn = _block_dev_queue_request,
+	.submit_bio = _blockdev_submit_bio,
 	.pending_rq_inc = _blockdev_pending_req_inc,
 	.pending_rq_dec = _blockdev_pending_req_dec,
 };
@@ -866,10 +927,23 @@ int block_dev_create_exported_object(ocf_core_t core)
 		return 0;
 	}
 
+	bvol->expobj_wq = alloc_workqueue("expobj_wq%s-%s",
+			WQ_MEM_RECLAIM | WQ_HIGHPRI, 0,
+			get_cache_id_string(cache),
+			get_core_id_string(core));
+	if (!bvol->expobj_wq) {
+		result = -ENOMEM;
+		goto end;
+	}
+
 	result = casdisk_functions.casdsk_exp_obj_create(dsk, dev_name,
 			THIS_MODULE, &_blockdev_exp_obj_ops);
-	if (!result)
-		bvol->expobj_valid = true;
+	if (result) {
+		destroy_workqueue(bvol->expobj_wq);
+		goto end;
+	}
+
+	bvol->expobj_valid = true;
 
 end:
 	if (result) {
@@ -899,6 +973,8 @@ int block_dev_destroy_exported_object(ocf_core_t core)
 	if (!bvol->expobj_valid)
 		return 0;
 
+	destroy_workqueue(bvol->expobj_wq);
+
 	ret = casdisk_functions.casdsk_exp_obj_lock(bvol->dsk);
 	if (ret) {
 		if (-EBUSY == ret)
@@ -907,11 +983,11 @@ int block_dev_destroy_exported_object(ocf_core_t core)
 	}
 
 	ret = casdisk_functions.casdsk_exp_obj_destroy(bvol->dsk);
-	casdisk_functions.casdsk_exp_obj_unlock(bvol->dsk);
-
 	if (!ret)
 		bvol->expobj_valid = false;
 
+	casdisk_functions.casdsk_exp_obj_unlock(bvol->dsk);
+
 	return ret;
 }
 
@@ -954,6 +1030,7 @@ static int _block_dev_stop_exported_object(ocf_core_t core, void *cntx)
 {
 	struct bd_object *bvol = bd_object(
 			ocf_core_get_volume(core));
+	int ret;
 
 	if (bvol->expobj_valid) {
 		BUG_ON(!bvol->expobj_locked);
@@ -961,8 +1038,9 @@ static int _block_dev_stop_exported_object(ocf_core_t core, void *cntx)
 		printk(KERN_INFO "Stopping device %s\n",
 			casdisk_functions.casdsk_exp_obj_get_gendisk(bvol->dsk)->disk_name);
 
-		casdisk_functions.casdsk_exp_obj_destroy(bvol->dsk);
-		bvol->expobj_valid = false;
+		ret = casdisk_functions.casdsk_exp_obj_destroy(bvol->dsk);
+		if (!ret)
+			bvol->expobj_valid = false;
 	}
 
 	if (bvol->expobj_locked) {
diff --git a/modules/cas_disk/cas_disk.h b/modules/cas_disk/cas_disk.h
index bb70d2a..78aecfb 100644
--- a/modules/cas_disk/cas_disk.h
+++ b/modules/cas_disk/cas_disk.h
@@ -11,13 +11,10 @@
 /**
  * Version of cas_disk interface
  */
-#define CASDSK_IFACE_VERSION 2
+#define CASDSK_IFACE_VERSION 3
 
 struct casdsk_disk;
 
-#define CASDSK_BIO_NOT_HANDLED 0
-#define CASDSK_BIO_HANDLED 1
-
 struct casdsk_exp_obj_ops {
 
 	/**
@@ -41,14 +38,11 @@ struct casdsk_exp_obj_ops {
 	int (*set_geometry)(struct casdsk_disk *dsk, void *private);
 
 	/**
-	 * @brief make_request_fn of exported object (top) block device.
+	 * @brief submit_bio of exported object (top) block device.
 	 * Called by cas_disk when cas_disk device is in attached mode.
 	 *
-	 * @return casdsk_BIO_HANDLED when bio was handled.
-	 * Otherwise casdsk_BIO_NOT_HANDLED. In this case bio will be submitted
-	 * to I/O scheduler and should be handled by request_fn.
 	 */
-	int (*make_request_fn)(struct casdsk_disk *dsk, struct request_queue *q,
+	void (*submit_bio)(struct casdsk_disk *dsk,
 			       struct bio *bio, void *private);
 
 	/**
diff --git a/modules/cas_disk/cas_disk_defs.h b/modules/cas_disk/cas_disk_defs.h
index b8ced1f..24ae5a2 100644
--- a/modules/cas_disk/cas_disk_defs.h
+++ b/modules/cas_disk/cas_disk_defs.h
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/kobject.h>
+#include <linux/blkdev.h>
 
 struct casdsk_stored_config {
 	size_t n_blobs;
diff --git a/modules/cas_disk/exp_obj.c b/modules/cas_disk/exp_obj.c
index 7842b4b..bfd309b 100644
--- a/modules/cas_disk/exp_obj.c
+++ b/modules/cas_disk/exp_obj.c
@@ -67,17 +67,9 @@ void casdsk_deinit_exp_objs(void)
 }
 
 static inline void _casdsk_exp_obj_handle_bio_att(struct casdsk_disk *dsk,
-						struct request_queue *q,
 						struct bio *bio)
 {
-	int status = CASDSK_BIO_NOT_HANDLED;
-
-	if (likely(dsk->exp_obj->ops->make_request_fn))
-		status = dsk->exp_obj->ops->
-				make_request_fn(dsk, q, bio, dsk->private);
-
-	if (status == CASDSK_BIO_NOT_HANDLED)
-		cas_call_default_mk_request_fn(dsk->exp_obj->mk_rq_fn, q, bio);
+	dsk->exp_obj->ops->submit_bio(dsk, bio, dsk->private);
 }
 
 CAS_DECLARE_BLOCK_CALLBACK(_casdsk_exp_obj_bio_pt_io, struct bio *bio,
@@ -102,7 +94,6 @@ CAS_DECLARE_BLOCK_CALLBACK(_casdsk_exp_obj_bio_pt_io, struct bio *bio,
 }
 
 static inline void _casdsk_exp_obj_handle_bio_pt(struct casdsk_disk *dsk,
-					       struct request_queue *q,
 					       struct bio *bio)
 {
 	struct bio *cloned_bio;
@@ -133,13 +124,12 @@ static inline void _casdsk_exp_obj_handle_bio_pt(struct casdsk_disk *dsk,
 }
 
 static inline void _casdsk_exp_obj_handle_bio(struct casdsk_disk *dsk,
-					    struct request_queue *q,
 					    struct bio *bio)
 {
 	if (likely(casdsk_disk_is_attached(dsk)))
-		_casdsk_exp_obj_handle_bio_att(dsk, q, bio);
+		_casdsk_exp_obj_handle_bio_att(dsk, bio);
 	else if (casdsk_disk_is_pt(dsk))
-		_casdsk_exp_obj_handle_bio_pt(dsk, q, bio);
+		_casdsk_exp_obj_handle_bio_pt(dsk, bio);
 	else if (casdsk_disk_is_shutdown(dsk))
 		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EIO));
 	else
@@ -176,26 +166,29 @@ retry:
 	return cpu;
 }
 
-static MAKE_RQ_RET_TYPE _casdsk_exp_obj_make_rq_fn(struct request_queue *q,
-						 struct bio *bio)
+static MAKE_RQ_RET_TYPE _casdsk_exp_obj_submit_bio(struct bio *bio)
 {
 	struct casdsk_disk *dsk;
 	unsigned int cpu;
 
 	BUG_ON(!bio);
-	BUG_ON(!q);
-	BUG_ON(!q->queuedata);
-	dsk = q->queuedata;
+	dsk = CAS_BIO_GET_GENDISK(bio)->private_data;
 
 	cpu = _casdsk_exp_obj_begin_rq(dsk);
 
-	_casdsk_exp_obj_handle_bio(dsk, q, bio);
+	_casdsk_exp_obj_handle_bio(dsk, bio);
 
 	_casdsk_exp_obj_end_rq(dsk, cpu);
 
 	KRETURN(0);
 }
 
+static MAKE_RQ_RET_TYPE _casdsk_exp_obj_make_rq_fn(struct request_queue *q,
+						 struct bio *bio)
+{
+	return _casdsk_exp_obj_submit_bio(bio);
+}
+
 static int _casdsk_get_next_part_no(struct block_device *bd)
 {
 	int part_no = 0;
@@ -369,6 +362,7 @@ static void _casdsk_exp_obj_clear_dev_t(struct casdsk_disk *dsk)
 
 static const struct block_device_operations _casdsk_exp_obj_ops = {
 	.owner = THIS_MODULE,
+	CAS_SET_SUBMIT_BIO(_casdsk_exp_obj_submit_bio)
 };
 
 static int casdsk_exp_obj_alloc(struct casdsk_disk *dsk)
@@ -611,7 +605,6 @@ int casdsk_exp_obj_create(struct casdsk_disk *dsk, const char *dev_name,
 	gd->private_data = dsk;
 	strlcpy(gd->disk_name, exp_obj->dev_name, sizeof(gd->disk_name));
 
-	dsk->exp_obj->mk_rq_fn = cas_get_default_mk_request_fn(queue);
 	cas_blk_queue_make_request(queue, _casdsk_exp_obj_make_rq_fn);
 
 	if (exp_obj->ops->set_geometry) {
diff --git a/modules/cas_disk/exp_obj.h b/modules/cas_disk/exp_obj.h
index ccd050f..616ee71 100644
--- a/modules/cas_disk/exp_obj.h
+++ b/modules/cas_disk/exp_obj.h
@@ -28,8 +28,6 @@ struct casdsk_exp_obj {
 
 	struct casdsk_exp_obj_ops *ops;
 
-	make_request_fn *mk_rq_fn;
-
 	const char *dev_name;
 	struct kobject kobj;
 

From b82b338c53a5840611e607bbecca7755a7467b7f Mon Sep 17 00:00:00 2001
From: Robert Baldyga <robert.baldyga@intel.com>
Date: Mon, 17 May 2021 16:50:44 +0200
Subject: [PATCH 3/9] Remove blk request handling path

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 configure.d/1_blk_status.conf                |   4 +-
 modules/cas_cache/volume/vol_blk_utils.h     |  11 -
 modules/cas_cache/volume/vol_block_dev_top.c | 423 -------------------
 modules/cas_disk/cas_disk.h                  |   7 -
 modules/cas_disk/exp_obj.c                   |  25 +-
 5 files changed, 4 insertions(+), 466 deletions(-)

diff --git a/configure.d/1_blk_status.conf b/configure.d/1_blk_status.conf
index 4db529c..e3197c4 100644
--- a/configure.d/1_blk_status.conf
+++ b/configure.d/1_blk_status.conf
@@ -21,10 +21,10 @@ apply() {
     case "$1" in
     "1")
 		add_define "CAS_BLK_STATUS_T blk_status_t"
-		add_define "CAS_BLK_STS_OK BLK_STS_OK" ;;
+		add_define "CAS_BLK_STS_NOTSUPP BLK_STS_NOTSUPP" ;;
     "2")
 		add_define "CAS_BLK_STATUS_T int"
-		add_define "CAS_BLK_STS_OK 0" ;;
+		add_define "CAS_BLK_STS_NOTSUPP -ENOTSUPP" ;;
 
     *)
         exit 1
diff --git a/modules/cas_cache/volume/vol_blk_utils.h b/modules/cas_cache/volume/vol_blk_utils.h
index 151154f..0d069a5 100644
--- a/modules/cas_cache/volume/vol_blk_utils.h
+++ b/modules/cas_cache/volume/vol_blk_utils.h
@@ -9,17 +9,6 @@
 #include "obj_blk.h"
 #include "context.h"
 
-static inline bool cas_blk_is_flush_io(unsigned long flags)
-{
-	if ((flags & CAS_WRITE_FLUSH) == CAS_WRITE_FLUSH)
-		return true;
-
-	if ((flags & CAS_WRITE_FLUSH_FUA) == CAS_WRITE_FLUSH_FUA)
-		return true;
-
-	return false;
-}
-
 struct blkio {
 	int error;
 	atomic_t rq_remaning;
diff --git a/modules/cas_cache/volume/vol_block_dev_top.c b/modules/cas_cache/volume/vol_block_dev_top.c
index 01af060..4dae980 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.c
+++ b/modules/cas_cache/volume/vol_block_dev_top.c
@@ -6,34 +6,6 @@
 #include "cas_cache.h"
 #include "utils/cas_err.h"
 
-#define BLK_RQ_POS(rq) (CAS_BIO_BISECTOR((rq)->bio))
-#define BLK_RQ_BYTES(rq) blk_rq_bytes(rq)
-
-static inline void _blockdev_end_request_all(struct request *rq, int error)
-{
-	CAS_END_REQUEST_ALL(rq, CAS_ERRNO_TO_BLK_STS(
-					map_cas_err_to_generic(error)));
-}
-
-static inline bool _blockdev_can_handle_rq(struct request *rq)
-{
-	int error = 0;
-
-	if (unlikely(!cas_is_rq_type_fs(rq)))
-		error = __LINE__;
-
-	if (unlikely(CAS_BLK_BIDI_RQ(rq)))
-		error = __LINE__;
-
-	if (error != 0) {
-		CAS_PRINT_RL(KERN_ERR "%s cannot handle request (ERROR %d)\n",
-			rq->rq_disk->disk_name, error);
-		return false;
-	}
-
-	return true;
-}
-
 static void _blockdev_set_bio_data(struct blk_data *data, struct bio *bio)
 {
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 14, 0)
@@ -80,400 +52,6 @@ void block_dev_start_bio(struct ocf_io *io)
 
 	data->start_time = _blockdev_start_io_acct(bio);
 }
-void block_dev_complete_rq(struct ocf_io *io, int error)
-
-{
-	struct blk_data *data = ocf_io_get_data(io);
-	struct request *rq = data->master_io_req;
-
-	_blockdev_end_request_all(rq, error);
-	ocf_io_put(io);
-	cas_free_blk_data(data);
-}
-
-void block_dev_complete_sub_rq(struct ocf_io *io, int error)
-{
-	struct blk_data *data = ocf_io_get_data(io);
-	struct ocf_io *master = data->master_io_req;
-	struct blk_data *master_data = ocf_io_get_data(master);
-
-	if (error)
-		master_data->error = error;
-
-	if (atomic_dec_return(&master_data->master_remaining) == 0) {
-		_blockdev_end_request_all(master_data->master_io_req,
-				master_data->error);
-		cas_free_blk_data(master_data);
-		ocf_io_put(master);
-	}
-
-	ocf_io_put(io);
-	cas_free_blk_data(data);
-}
-
-void block_dev_complete_flush(struct ocf_io *io, int error)
-{
-	struct request *rq = io->priv1;
-
-	_blockdev_end_request_all(rq, error);
-	ocf_io_put(io);
-}
-
-bool _blockdev_is_request_barier(struct request *rq)
-{
-	struct bio *i_bio = rq->bio;
-
-	for_each_bio(i_bio) {
-		if (CAS_CHECK_BARRIER(i_bio))
-			return true;
-	}
-	return false;
-}
-
-static int _blockdev_alloc_many_requests(ocf_core_t core,
-		struct list_head *list, struct request *rq,
-		struct ocf_io *master)
-{
-	ocf_cache_t cache = ocf_core_get_cache(core);
-	struct cache_priv *cache_priv = ocf_cache_get_priv(cache);
-	int error = 0;
-	int flags = 0;
-	struct bio *bio;
-	struct ocf_io *sub_io;
-	struct blk_data *master_data = ocf_io_get_data(master);
-	struct blk_data *data;
-
-	INIT_LIST_HEAD(list);
-
-	/* Go over requests and allocate sub requests */
-	bio = rq->bio;
-	for_each_bio(bio) {
-		/* Setup BIO flags */
-		if (CAS_IS_WRITE_FLUSH_FUA(CAS_BIO_OP_FLAGS(bio))) {
-			/* FLUSH and FUA */
-			flags = CAS_WRITE_FLUSH_FUA;
-		} else if (CAS_IS_WRITE_FUA(CAS_BIO_OP_FLAGS(bio))) {
-			/* FUA */
-			flags = CAS_WRITE_FUA;
-		} else if (CAS_IS_WRITE_FLUSH(CAS_BIO_OP_FLAGS(bio))) {
-			/* FLUSH - It shall be handled in request handler */
-			error = -EINVAL;
-			break;
-		} else {
-			flags = 0;
-		}
-
-		data = cas_alloc_blk_data(bio_segments(bio), GFP_NOIO);
-		if (!data) {
-			CAS_PRINT_RL(KERN_CRIT "BIO data vector allocation error\n");
-			error = -ENOMEM;
-			break;
-		}
-
-		_blockdev_set_bio_data(data, bio);
-
-		data->master_io_req = master;
-
-		sub_io = ocf_core_new_io(core,
-				cache_priv->io_queues[smp_processor_id()],
-				CAS_BIO_BISECTOR(bio) << SECTOR_SHIFT,
-				CAS_BIO_BISIZE(bio), (bio_data_dir(bio) == READ) ?
-						OCF_READ : OCF_WRITE,
-				cas_cls_classify(cache, bio), flags);
-
-		if (!sub_io) {
-			cas_free_blk_data(data);
-			error = -ENOMEM;
-			break;
-		}
-
-		data->io = sub_io;
-
-		error = ocf_io_set_data(sub_io, data, 0);
-		if (error) {
-			ocf_io_put(sub_io);
-			cas_free_blk_data(data);
-			break;
-		}
-
-		ocf_io_set_cmpl(sub_io, NULL, NULL, block_dev_complete_sub_rq);
-
-		list_add_tail(&data->list, list);
-		atomic_inc(&master_data->master_remaining);
-	}
-
-	if (error) {
-		CAS_PRINT_RL(KERN_ERR "Cannot handle request (ERROR %d)\n", error);
-
-		/* Go over list and free all */
-		while (!list_empty(list)) {
-			data = list_first_entry(list, struct blk_data, list);
-			list_del(&data->list);
-
-			sub_io = data->io;
-			ocf_io_put(sub_io);
-			cas_free_blk_data(data);
-		}
-	}
-
-	return error;
-}
-
-static void _blockdev_set_request_data(struct blk_data *data, struct request *rq)
-{
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 14, 0)
-	struct req_iterator iter;
-	struct bio_vec *bvec;
-	uint32_t i = 0;
-
-	rq_for_each_segment(bvec, rq, iter) {
-		BUG_ON(i >= data->size);
-		data->vec[i] = *bvec;
-		i++;
-	}
-#else
-	struct req_iterator iter;
-	struct bio_vec bvec;
-	uint32_t i = 0;
-
-	rq_for_each_segment(bvec, rq, iter) {
-		BUG_ON(i >= data->size);
-		data->vec[i] = bvec;
-		i++;
-	}
-#endif
-}
-
-/**
- * @brief push flush request upon execution queue for given core device
- */
-static int _blkdev_handle_flush_request(struct request *rq, ocf_core_t core)
-{
-	struct ocf_io *io;
-	ocf_cache_t cache = ocf_core_get_cache(core);
-	struct cache_priv *cache_priv = ocf_cache_get_priv(cache);
-
-	io = ocf_core_new_io(core, cache_priv->io_queues[smp_processor_id()],
-			0, 0, OCF_WRITE, 0, CAS_WRITE_FLUSH);
-	if (!io)
-		return -ENOMEM;
-
-	ocf_io_set_cmpl(io, rq, NULL, block_dev_complete_flush);
-
-	ocf_core_submit_flush(io);
-
-	return 0;
-}
-
-#ifdef RQ_CHECK_CONTINOUS
-static inline bool _bvec_is_mergeable(struct bio_vec *bv1, struct bio_vec *bv2)
-{
-	if (bv1 == NULL)
-		return true;
-
-	if (BIOVEC_PHYS_MERGEABLE(bv1, bv2))
-		return true;
-
-	return !bv2->bv_offset && !((bv1->bv_offset + bv1->bv_len) % PAGE_SIZE);
-}
-#endif
-
-static uint32_t _blkdev_scan_request(ocf_cache_t cache, struct request *rq,
-		struct ocf_io *io, bool *single_io)
-{
-	uint32_t size = 0;
-	struct req_iterator iter;
-	struct bio *bio_prev = NULL;
-	uint32_t io_class;
-
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 14, 0)
-	struct bio_vec bvec;
-#ifdef RQ_CHECK_CONTINOUS
-	struct bio_vec bvec_prev = { NULL, };
-#endif
-#else
-	struct bio_vec *bvec;
-#ifdef RQ_CHECK_CONTINOUS
-	struct bio_vec *bvec_prev = NULL;
-#endif
-#endif
-
-	*single_io = true;
-
-	/* Scan BIOs in the request to:
-	 * 1. Count the segments number
-	 * 2. Check if requests contains many IO classes
-	 * 3. Check if request is continuous (when process kernel stack is 8KB)
-	 */
-	rq_for_each_segment(bvec, rq, iter) {
-		/* Increase BIO data vector counter */
-		size++;
-
-		if (*single_io == false) {
-			/* Already detected complex request */
-			continue;
-		}
-
-#ifdef RQ_CHECK_CONTINOUS
-		/*
-		 * If request is not continous submit each bio as separate
-		 * request, and prevent nvme driver from splitting requests.
-		 * For large requests, nvme splitting causes stack overrun.
-		 */
-		if (!_bvec_is_mergeable(CAS_SEGMENT_BVEC(bvec_prev),
-				CAS_SEGMENT_BVEC(bvec))) {
-			*single_io = false;
-			continue;
-		}
-		bvec_prev = bvec;
-#endif
-
-		if (bio_prev == iter.bio)
-			continue;
-
-		bio_prev = iter.bio;
-
-		/* Get class ID for given BIO */
-		io_class = cas_cls_classify(cache, iter.bio);
-
-		if (io->io_class != io_class) {
-			/*
-			 * Request contains BIO with different IO classes and
-			 * need to handle BIO separately
-			 */
-			*single_io = false;
-		}
-	}
-
-	return size;
-}
-
-static int __block_dev_queue_rq(struct request *rq, ocf_core_t core)
-{
-	ocf_cache_t cache = ocf_core_get_cache(core);
-	struct cache_priv *cache_priv = ocf_cache_get_priv(cache);
-	struct ocf_io *io;
-	struct blk_data *data;
-	int master_flags = 0;
-	bool single_io;
-	uint32_t size;
-	int ret;
-
-	if (_blockdev_is_request_barier(rq) || !_blockdev_can_handle_rq(rq)) {
-		CAS_PRINT_RL(KERN_WARNING
-			"special bio was sent,not supported!\n");
-		return -ENOTSUPP;
-	}
-
-	if ((rq->cmd_flags & REQ_FUA) && CAS_RQ_IS_FLUSH(rq)) {
-		/* FLUSH and FUA */
-		master_flags = CAS_WRITE_FLUSH_FUA;
-	} else if (rq->cmd_flags & REQ_FUA) {
-		/* FUA */
-		master_flags = CAS_WRITE_FUA;
-	} else if (CAS_RQ_IS_FLUSH(rq)) {
-		/* FLUSH */
-		return _blkdev_handle_flush_request(rq, core);
-	}
-
-	io = ocf_core_new_io(core, cache_priv->io_queues[smp_processor_id()],
-			BLK_RQ_POS(rq) << SECTOR_SHIFT, BLK_RQ_BYTES(rq),
-			(rq_data_dir(rq) == CAS_RQ_DATA_DIR_WR) ?
-					OCF_WRITE : OCF_READ,
-			cas_cls_classify(cache, rq->bio), master_flags);
-	if (!io) {
-		CAS_PRINT_RL(KERN_CRIT "Out of memory. Ending IO processing.\n");
-		return -ENOMEM;
-	}
-
-
-	size = _blkdev_scan_request(cache, rq, io, &single_io);
-
-	if (unlikely(size == 0)) {
-		CAS_PRINT_RL(KERN_ERR "Empty IO request\n");
-		ocf_io_put(io);
-		return -EINVAL;
-	}
-
-	if (single_io) {
-		data = cas_alloc_blk_data(size, GFP_NOIO);
-		if (data == NULL) {
-			CAS_PRINT_RL(KERN_CRIT
-				"Out of memory. Ending IO processing.\n");
-			ocf_io_put(io);
-			return -ENOMEM;
-		}
-
-		_blockdev_set_request_data(data, rq);
-
-		data->master_io_req = rq;
-
-		ret = ocf_io_set_data(io, data, 0);
-		if (ret) {
-			ocf_io_put(io);
-			cas_free_blk_data(data);
-			return -EINVAL;
-		}
-
-		ocf_io_set_cmpl(io, NULL, NULL, block_dev_complete_rq);
-
-		ocf_core_submit_io(io);
-	} else {
-		struct list_head list = LIST_HEAD_INIT(list);
-
-		data = cas_alloc_blk_data(0, GFP_NOIO);
-		if (data == NULL) {
-			printk(KERN_CRIT
-				"Out of memory. Ending IO processing.\n");
-			ocf_io_put(io);
-			return -ENOMEM;
-		}
-		data->master_io_req = rq;
-
-		if (ocf_io_set_data(io, data, 0)) {
-			ocf_io_put(io);
-			cas_free_blk_data(data);
-			return -EINVAL;
-		}
-
-		/* Allocate setup and setup */
-		ret = _blockdev_alloc_many_requests(core, &list, rq, io);
-		if (ret < 0) {
-			printk(KERN_CRIT
-				"Out of memory. Ending IO processing.\n");
-			cas_free_blk_data(data);
-			ocf_io_put(io);
-			return -ENOMEM;
-		}
-
-		BUG_ON(list_empty(&list));
-
-		/* Go over list and push request to the engine */
-		while (!list_empty(&list)) {
-			struct ocf_io *sub_io;
-
-			data = list_first_entry(&list, struct blk_data, list);
-			list_del(&data->list);
-
-			sub_io = data->io;
-
-			ocf_core_submit_io(sub_io);
-		}
-	}
-
-	return ret;
-}
-
-static CAS_BLK_STATUS_T _block_dev_queue_request(struct casdsk_disk *dsk, struct request *rq, void *private)
-{
-	ocf_core_t core = private;
-	int ret = __block_dev_queue_rq(rq, core);
-	if (ret)
-		_blockdev_end_request_all(rq, ret);
-
-	return CAS_ERRNO_TO_BLK_STS(ret);
-}
-
 static inline int _blkdev_can_hndl_bio(struct bio *bio)
 {
 	if (CAS_CHECK_BARRIER(bio)) {
@@ -847,7 +425,6 @@ static void _blockdev_submit_bio(struct casdsk_disk *dsk,
 
 static struct casdsk_exp_obj_ops _blockdev_exp_obj_ops = {
 	.set_geometry = _blockdev_set_geometry,
-	.queue_rq_fn = _block_dev_queue_request,
 	.submit_bio = _blockdev_submit_bio,
 	.pending_rq_inc = _blockdev_pending_req_inc,
 	.pending_rq_dec = _blockdev_pending_req_dec,
diff --git a/modules/cas_disk/cas_disk.h b/modules/cas_disk/cas_disk.h
index 78aecfb..17d2b6b 100644
--- a/modules/cas_disk/cas_disk.h
+++ b/modules/cas_disk/cas_disk.h
@@ -45,13 +45,6 @@ struct casdsk_exp_obj_ops {
 	void (*submit_bio)(struct casdsk_disk *dsk,
 			       struct bio *bio, void *private);
 
-	/**
-	 * @brief queue_rq_fn of exported object (top) block device.
-	 * Called by cas_disk when cas_disk device is in attached mode.
-	 */
-	CAS_BLK_STATUS_T (*queue_rq_fn)(struct casdsk_disk *dsk, struct request *rq,
-			   void *private);
-
 	/**
 	 * @brief Increment exported object pending request counter.
 	 */
diff --git a/modules/cas_disk/exp_obj.c b/modules/cas_disk/exp_obj.c
index bfd309b..fee97fa 100644
--- a/modules/cas_disk/exp_obj.c
+++ b/modules/cas_disk/exp_obj.c
@@ -461,30 +461,9 @@ static int _casdsk_exp_obj_init_kobject(struct casdsk_disk *dsk)
 }
 
 static CAS_BLK_STATUS_T _casdsk_exp_obj_queue_rq(struct blk_mq_hw_ctx *hctx,
-			const struct blk_mq_queue_data *bd)
+		const struct blk_mq_queue_data *bd)
 {
-	struct casdsk_disk *dsk = hctx->driver_data;
-	struct casdsk_exp_obj *exp_obj = dsk->exp_obj;
-	struct request *rq = bd->rq;
-	CAS_BLK_STATUS_T result = CAS_BLK_STS_OK;
-
-	if (likely(exp_obj->ops && exp_obj->ops->queue_rq_fn)) {
-		exp_obj->ops->pending_rq_inc(dsk, dsk->private);
-
-		result = exp_obj->ops->queue_rq_fn(dsk, rq, dsk->private);
-
-		exp_obj->ops->pending_rq_dec(dsk, dsk->private);
-	} else {
-		/*
-		* queue_rq_fn() is required, as we can't do any default
-		* action in attached mode. In PT mode we handle all bios
-		* directly in make_request_fn(), so queue_rq_fn() will not
-		* be called.
-		*/
-		BUG_ON(rq);
-	}
-
-	return result;
+	return CAS_BLK_STS_NOTSUPP;
 }
 
 static struct blk_mq_ops casdsk_mq_ops = {

From 7f89e59b1ad226a147d6e59d1684b83c8239556e Mon Sep 17 00:00:00 2001
From: Robert Baldyga <robert.baldyga@intel.com>
Date: Wed, 19 May 2021 23:34:13 +0200
Subject: [PATCH 4/9] Remove CAS_FLUSH_SUPPORTED

It's defined on every single supported kernel, so there is actually no need
for this define at all.

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 modules/cas_cache/volume/vol_atomic_dev_bottom.c | 13 -------------
 modules/cas_cache/volume/vol_block_dev_bottom.c  | 13 -------------
 modules/cas_cache/volume/vol_block_dev_top.c     |  2 --
 3 files changed, 28 deletions(-)

diff --git a/modules/cas_cache/volume/vol_atomic_dev_bottom.c b/modules/cas_cache/volume/vol_atomic_dev_bottom.c
index 82046a5..ef956e4 100644
--- a/modules/cas_cache/volume/vol_atomic_dev_bottom.c
+++ b/modules/cas_cache/volume/vol_atomic_dev_bottom.c
@@ -832,7 +832,6 @@ out:
 
 void cas_atomic_submit_flush(struct ocf_io *io)
 {
-#ifdef CAS_FLUSH_SUPPORTED
 	struct bd_object *bdobj = bd_object(ocf_io_get_volume(io));
 	struct block_device *bdev = bdobj->btm_bd;
 	struct request_queue *q = bdev_get_queue(bdev);
@@ -885,18 +884,6 @@ void cas_atomic_submit_flush(struct ocf_io *io)
 
 out:
 	cas_atomic_end_atom(atom, blkio->error);
-#else
-	/* Running operating system without support for REQ_FLUSH
-	 * (i.e. SLES 11 SP 1) CAS cannot use flushing requests to handle
-	 * power-fail safe Write-Back
-	 */
-	struct blkio *bdio = cas_io_to_blkio(io);
-
-	io->end(io, -EINVAL);
-	/* on SLES 11 SP 1 powerfail safety can only be achieved through
-	 * disabling volatile write cache of disk itself.
-	 */
-#endif
 }
 
 void cas_atomic_submit_io(struct ocf_io *io)
diff --git a/modules/cas_cache/volume/vol_block_dev_bottom.c b/modules/cas_cache/volume/vol_block_dev_bottom.c
index dae8728..949b66e 100644
--- a/modules/cas_cache/volume/vol_block_dev_bottom.c
+++ b/modules/cas_cache/volume/vol_block_dev_bottom.c
@@ -229,7 +229,6 @@ CAS_DECLARE_BLOCK_CALLBACK(cas_bd_io_end, struct bio *bio,
 
 static void block_dev_submit_flush(struct ocf_io *io)
 {
-#ifdef CAS_FLUSH_SUPPORTED
 	struct blkio *blkio = cas_io_to_blkio(io);
 	struct bd_object *bdobj = bd_object(ocf_io_get_volume(io));
 	struct block_device *bdev = bdobj->btm_bd;
@@ -271,18 +270,6 @@ static void block_dev_submit_flush(struct ocf_io *io)
 
 out:
 	cas_bd_io_end(io, blkio->error);
-
-#else
-	/* Running operating system without support for REQ_FLUSH
-	 * (i.e. SLES 11 SP 1) CAS cannot use flushing requests to
-	 * handle power-fail safe Write-Back
-	 */
-	io->end(io, -ENOTSUPP);
-
-	/* on SLES 11 SP 1 powerfail safety can only be achieved
-	 * through disabling volatile write cache of disk itself.
-	 */
-#endif
 }
 
 void block_dev_submit_discard(struct ocf_io *io)
diff --git a/modules/cas_cache/volume/vol_block_dev_top.c b/modules/cas_cache/volume/vol_block_dev_top.c
index 4dae980..18e5cea 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.c
+++ b/modules/cas_cache/volume/vol_block_dev_top.c
@@ -66,7 +66,6 @@ static inline int _blkdev_can_hndl_bio(struct bio *bio)
 
 void _blockdev_set_exported_object_flush_fua(ocf_core_t core)
 {
-#ifdef CAS_FLUSH_SUPPORTED
 	ocf_cache_t cache = ocf_core_get_cache(core);
 	ocf_volume_t core_vol = ocf_core_get_volume(core);
 	ocf_volume_t cache_vol = ocf_cache_get_volume(cache);
@@ -87,7 +86,6 @@ void _blockdev_set_exported_object_flush_fua(ocf_core_t core)
 	fua = (CAS_CHECK_QUEUE_FUA(core_q) || CAS_CHECK_QUEUE_FUA(cache_q));
 
 	cas_set_queue_flush_fua(exp_q, flush, fua);
-#endif
 }
 
 static void _blockdev_set_discard_properties(ocf_cache_t cache,

From c7ac8c55f42eab3864ba7b735ef47ad593e9aa6e Mon Sep 17 00:00:00 2001
From: Robert Baldyga <robert.baldyga@intel.com>
Date: Mon, 17 May 2021 16:57:32 +0200
Subject: [PATCH 5/9] Remove unused configs

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 configure.d/1_blk_bidi_req.conf         | 33 -------------
 configure.d/1_default_make_request.conf | 54 ---------------------
 configure.d/1_req_flush.conf            | 40 ----------------
 configure.d/1_req_fs.conf               | 47 ------------------
 configure.d/1_write_fua.conf            | 55 ---------------------
 configure.d/2_flush_fua.conf            | 55 ---------------------
 configure.d/2_write_flush.conf          | 63 -------------------------
 7 files changed, 347 deletions(-)
 delete mode 100644 configure.d/1_blk_bidi_req.conf
 delete mode 100644 configure.d/1_default_make_request.conf
 delete mode 100644 configure.d/1_req_flush.conf
 delete mode 100644 configure.d/1_req_fs.conf
 delete mode 100644 configure.d/1_write_fua.conf
 delete mode 100644 configure.d/2_flush_fua.conf
 delete mode 100644 configure.d/2_write_flush.conf

diff --git a/configure.d/1_blk_bidi_req.conf b/configure.d/1_blk_bidi_req.conf
deleted file mode 100644
index 967aa23..0000000
--- a/configure.d/1_blk_bidi_req.conf
+++ /dev/null
@@ -1,33 +0,0 @@
-#!/bin/bash
-#
-# Copyright(c) 2012-2021 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause-Clear
-#
-
-. $(dirname $3)/conf_framework
-
-check() {
-    cur_name=$(basename $2)
-    config_file_path=$1
-    if compile_module $cur_name "blk_bidi_rq(rq);" "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_define "CAS_BLK_BIDI_RQ(rq) \\
-            blk_bidi_rq(rq)" ;;
-    "2")
-        add_define "CAS_BLK_BIDI_RQ(rq) \\
-            false" ;;
-    *)
-        exit 1
-    esac
-}
-
-conf_run $@
diff --git a/configure.d/1_default_make_request.conf b/configure.d/1_default_make_request.conf
deleted file mode 100644
index 1b9301d..0000000
--- a/configure.d/1_default_make_request.conf
+++ /dev/null
@@ -1,54 +0,0 @@
-#!/bin/bash
-#
-# Copyright(c) 2012-2021 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause-Clear
-#
-
-. $(dirname $3)/conf_framework
-
-check() {
-    cur_name=$(basename $2)
-    config_file_path=$1
-    if compile_module $cur_name "blk_mq_make_request(NULL, NULL);" "linux/blk-mq.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_get_default_mk_request_fn(struct request_queue *q)
-        {
-            if (q->make_request_fn)
-                return q->make_request_fn;
-            return blk_mq_make_request;
-        }"
-        add_function "
-        static inline void cas_call_default_mk_request_fn(make_request_fn *fn,
-            struct request_queue *q, struct bio *bio)
-        {
-            percpu_ref_get(&q->q_usage_counter);
-            fn(q, bio);
-        }" ;;
-    "2")
-        add_function "
-        static inline void *cas_get_default_mk_request_fn(struct request_queue *q)
-        {
-            return q->make_request_fn;
-        }"
-        add_function "
-        static inline void cas_call_default_mk_request_fn(make_request_fn *fn,
-            struct request_queue *q, struct bio *bio)
-        {
-            fn(q, bio);
-        }" ;;
-    *)
-        exit 1
-    esac
-}
-
-conf_run $@
diff --git a/configure.d/1_req_flush.conf b/configure.d/1_req_flush.conf
deleted file mode 100644
index 0648fc9..0000000
--- a/configure.d/1_req_flush.conf
+++ /dev/null
@@ -1,40 +0,0 @@
-#!/bin/bash
-#
-# Copyright(c) 2012-2021 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause-Clear
-#
-
-. $(dirname $3)/conf_framework
-
-check() {
-	cur_name=$(basename $2)
-	config_file_path=$1
-	if compile_module $cur_name "REQ_PREFLUSH" "linux/blk_types.h"
-	then
-		echo $cur_name "1" >> $config_file_path
-	elif compile_module $cur_name "REQ_FLUSH" "linux/blk_types.h"
-	then
-		echo $cur_name "2" >> $config_file_path
-    else
-        echo $cur_name "X" >> $config_file_path
-    fi
-}
-
-apply() {
-    case "$1" in
-    "1")
-		add_define "CAS_REQ_FLUSH \\
-			REQ_PREFLUSH"
-		add_define "CAS_FLUSH_SUPPORTED \\
-			1" ;;
-    "2")
-		add_define "CAS_REQ_FLUSH \\
-			REQ_FLUSH"
-		add_define "CAS_FLUSH_SUPPORTED \\
-			1" ;;
-    *)
-        exit 1
-    esac
-}
-
-conf_run $@
diff --git a/configure.d/1_req_fs.conf b/configure.d/1_req_fs.conf
deleted file mode 100644
index 6a972d7..0000000
--- a/configure.d/1_req_fs.conf
+++ /dev/null
@@ -1,47 +0,0 @@
-#!/bin/bash
-#
-# Copyright(c) 2012-2021 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause-Clear
-#
-
-. $(dirname $3)/conf_framework
-
-check() {
-	cur_name=$(basename $2)
-	config_file_path=$1
-	if compile_module $cur_name "REQ_TYPE_FS" "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 int cas_is_rq_type_fs(struct request *rq)
-	{
-		return rq->cmd_type == REQ_TYPE_FS;
-	}" ;;
-    "2")
-		add_function "
-	static inline int cas_is_rq_type_fs(struct request *rq)
-	{
-		switch (req_op(rq)){
-		case REQ_OP_READ:
-		case REQ_OP_WRITE:
-		case REQ_OP_FLUSH:
-		case REQ_OP_DISCARD:
-			return true;
-		default:
-			return false;
-		}
-	}" ;;
-    *)
-        exit 1
-    esac
-}
-
-conf_run $@
diff --git a/configure.d/1_write_fua.conf b/configure.d/1_write_fua.conf
deleted file mode 100644
index b636fec..0000000
--- a/configure.d/1_write_fua.conf
+++ /dev/null
@@ -1,55 +0,0 @@
-#!/bin/bash
-#
-# Copyright(c) 2012-2021 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause-Clear
-#
-
-. $(dirname $3)/conf_framework
-
-check() {
-	cur_name=$(basename $2)
-	config_file_path=$1
-	if compile_module $cur_name "WRITE_FUA" "linux/fs.h"
-	then
-		if compile_module $cur_name "BIO_FUA" "linux/bio.h"
-		then
-			echo $cur_name "1" >> $config_file_path
-		else
-			echo $cur_name "2" >> $config_file_path
-		fi
-	elif compile_module $cur_name "REQ_FUA" "linux/blk_types.h"
-	then
-		echo $cur_name "3" >> $config_file_path
-	else
-		echo $cur_name "4" >> $config_file_path
-    fi
-}
-
-apply() {
-    case "$1" in
-    "1")
-		add_define "CAS_WRITE_FUA \\
-			WRITE_FUA"
-		add_define "CAS_IS_WRITE_FUA(flags) \\
-			((flags) & BIO_FUA)" ;;
-    "2")
-		add_define "CAS_WRITE_FUA \\
-			WRITE_FUA"
-		add_define "CAS_IS_WRITE_FUA(flags) \\
-			((flags) & REQ_FUA)" ;;
-	"3")
-		add_define "CAS_IS_WRITE_FUA(flags) \\
-			((flags) & REQ_FUA)"
-		add_define "CAS_WRITE_FUA \\
-			REQ_FUA" ;;
-	"4")
-		add_define "CAS_IS_WRITE_FUA(flags) \\
-			0"
-		add_define "CAS_WRITE_FUA \\
-			WRITE_BARRIER" ;;
-    *)
-        exit 1
-    esac
-}
-
-conf_run $@
diff --git a/configure.d/2_flush_fua.conf b/configure.d/2_flush_fua.conf
deleted file mode 100644
index 190ff58..0000000
--- a/configure.d/2_flush_fua.conf
+++ /dev/null
@@ -1,55 +0,0 @@
-#!/bin/bash
-#
-# Copyright(c) 2012-2021 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause-Clear
-#
-
-. $(dirname $3)/conf_framework
-
-check() {
-	cur_name=$(basename $2)
-	config_file_path=$1
-	if compile_module $cur_name "WRITE_FLUSH_FUA" "linux/fs.h"
-	then
-		if compile_module $cur_name "BIO_FUA" "linux/bio.h"
-		then
-			echo $cur_name "1" >> $config_file_path
-		else
-			echo $cur_name "2" >> $config_file_path
-		fi
-	elif compile_module $cur_name "REQ_PREFLUSH" "linux/blk_types.h"
-	then
-		echo $cur_name "3" >> $config_file_path
-	else
-		echo $cur_name "4" >> $config_file_path
-	fi
-}
-
-apply() {
-    case "$1" in
-	"1")
-		add_define "CAS_WRITE_FLUSH_FUA \\
-			WRITE_FLUSH_FUA"
-		add_define "CAS_IS_WRITE_FLUSH_FUA(flags) \\
-			((BIO_FUA | BIO_FLUSH) == ((flags) & (BIO_FUA | BIO_FLUSH)))" ;;
-	"2")
-		add_define "CAS_WRITE_FLUSH_FUA \\
-			WRITE_FLUSH_FUA"
-		add_define "CAS_IS_WRITE_FLUSH_FUA(flags) \\
-			((REQ_FUA | CAS_REQ_FLUSH) == ((flags) & (REQ_FUA | CAS_REQ_FLUSH)))" ;;
-	"3")
-		add_define "CAS_IS_WRITE_FLUSH_FUA(flags) \\
-			((REQ_PREFLUSH | REQ_FUA) == ((flags) & (REQ_PREFLUSH |REQ_FUA)))"
-		add_define "CAS_WRITE_FLUSH_FUA \\
-			(REQ_PREFLUSH | REQ_FUA)" ;;
-	"4")
-		add_define "CAS_IS_WRITE_FLUSH_FUA(flags) \\
-			0"
-		add_define "CAS_WRITE_FLUSH_FUA \\
-			WRITE_BARRIER" ;;
-    *)
-        exit 1
-    esac
-}
-
-conf_run $@
diff --git a/configure.d/2_write_flush.conf b/configure.d/2_write_flush.conf
deleted file mode 100644
index 6d0a5d5..0000000
--- a/configure.d/2_write_flush.conf
+++ /dev/null
@@ -1,63 +0,0 @@
-#!/bin/bash
-#
-# Copyright(c) 2012-2021 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause-Clear
-#
-
-. $(dirname $3)/conf_framework
-
-check() {
-	cur_name=$(basename $2)
-	config_file_path=$1
-	if compile_module $cur_name "WRITE_FLUSH" "linux/fs.h"
-	then
-		if compile_module $cur_name "BIO_FLUSH" "linux/bio.h"
-		then
-			echo $cur_name "1" >> $config_file_path
-		else
-			echo $cur_name "2" >> $config_file_path
-		fi
-	elif compile_module $cur_name "REQ_PREFLUSH" "linux/blk_types.h"
-	then
-		echo $cur_name "3" >> $config_file_path
-	else
-		echo $cur_name "4" >> $config_file_path
-    fi
-}
-
-apply() {
-    case "$1" in
-    "1")
-		add_define "CAS_RQ_IS_FLUSH(rq) \\
-			((rq)->cmd_flags & CAS_REQ_FLUSH)"
-		add_define "CAS_WRITE_FLUSH \\
-			WRITE_FLUSH"
-		add_define "CAS_IS_WRITE_FLUSH(flags) \\
-			((flags) & BIO_FLUSH)" ;;
-    "2")
-		add_define "CAS_RQ_IS_FLUSH(rq) \\
-			((rq)->cmd_flags & CAS_REQ_FLUSH)"
-		add_define "CAS_WRITE_FLUSH \\
-			WRITE_FLUSH"
-		add_define "CAS_IS_WRITE_FLUSH(flags) \\
-			((flags) & CAS_REQ_FLUSH)" ;;
-	"3")
-		add_define "CAS_RQ_IS_FLUSH(rq) \\
-			((rq)->cmd_flags & REQ_PREFLUSH)"
-		add_define "CAS_WRITE_FLUSH \\
-			(REQ_OP_WRITE | REQ_PREFLUSH)"
-		add_define "CAS_IS_WRITE_FLUSH(flags) \\
-			(CAS_WRITE_FLUSH == ((flags) & CAS_WRITE_FLUSH))" ;;
-	"4")
-		add_define "CAS_RQ_IS_FLUSH(rq) \\
-			0"
-		add_define "CAS_IS_WRITE_FLUSH(flags) \\
-			(WRITE_BARRIER == ((flags) & WRITE_BARRIER))"
-		add_define "CAS_WRITE_FLUSH \\
-			WRITE_BARRIER" ;;
-    *)
-        exit 1
-    esac
-}
-
-conf_run $@

From 5e17d0833f117ca70db073999aaf832a30e1fd20 Mon Sep 17 00:00:00 2001
From: Robert Baldyga <robert.baldyga@intel.com>
Date: Mon, 17 May 2021 16:51:11 +0200
Subject: [PATCH 6/9] Remove unused callbacks from cas_disk ops

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 modules/cas_cache/volume/vol_block_dev_top.c | 32 --------------------
 modules/cas_disk/cas_disk.h                  | 32 --------------------
 2 files changed, 64 deletions(-)

diff --git a/modules/cas_cache/volume/vol_block_dev_top.c b/modules/cas_cache/volume/vol_block_dev_top.c
index 18e5cea..e8d33b1 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.c
+++ b/modules/cas_cache/volume/vol_block_dev_top.c
@@ -178,36 +178,6 @@ static int _blockdev_set_geometry(struct casdsk_disk *dsk, void *private)
 	return 0;
 }
 
-static void _blockdev_pending_req_inc(struct casdsk_disk *dsk, void *private)
-{
-	ocf_core_t core;
-	ocf_volume_t obj;
-	struct bd_object *bvol;
-
-	BUG_ON(!private);
-	core = private;
-	obj = ocf_core_get_volume(core);
-	bvol = bd_object(obj);
-	BUG_ON(!bvol);
-
-	atomic64_inc(&bvol->pending_rqs);
-}
-
-static void _blockdev_pending_req_dec(struct casdsk_disk *dsk, void *private)
-{
-	ocf_core_t core;
-	ocf_volume_t obj;
-	struct bd_object *bvol;
-
-	BUG_ON(!private);
-	core = private;
-	obj = ocf_core_get_volume(core);
-	bvol = bd_object(obj);
-	BUG_ON(!bvol);
-
-	atomic64_dec(&bvol->pending_rqs);
-}
-
 struct defer_bio_context {
 	struct work_struct io_work;
 	void (*cb)(ocf_core_t core, struct bio *bio);
@@ -424,8 +394,6 @@ static void _blockdev_submit_bio(struct casdsk_disk *dsk,
 static struct casdsk_exp_obj_ops _blockdev_exp_obj_ops = {
 	.set_geometry = _blockdev_set_geometry,
 	.submit_bio = _blockdev_submit_bio,
-	.pending_rq_inc = _blockdev_pending_req_inc,
-	.pending_rq_dec = _blockdev_pending_req_dec,
 };
 
 /**
diff --git a/modules/cas_disk/cas_disk.h b/modules/cas_disk/cas_disk.h
index 17d2b6b..cbc8911 100644
--- a/modules/cas_disk/cas_disk.h
+++ b/modules/cas_disk/cas_disk.h
@@ -16,21 +16,6 @@
 struct casdsk_disk;
 
 struct casdsk_exp_obj_ops {
-
-	/**
-	 * @brief Prepare request queue of exported object (top) block device.
-	 *	Could be NULL.
-	 */
-	int (*prepare_queue)(struct casdsk_disk *dsk, struct request_queue *q,
-			     void *private);
-
-	/**
-	 * @brief Cleanup request queue of exported object (top) block device.
-	 *	Could be NULL.
-	 */
-	void (*cleanup_queue)(struct casdsk_disk *dsk, struct request_queue *q,
-			      void *private);
-
 	/**
 	 * @brief Set geometry of exported object (top) block device.
 	 *	Could be NULL.
@@ -44,23 +29,6 @@ struct casdsk_exp_obj_ops {
 	 */
 	void (*submit_bio)(struct casdsk_disk *dsk,
 			       struct bio *bio, void *private);
-
-	/**
-	 * @brief Increment exported object pending request counter.
-	 */
-	void (*pending_rq_inc)(struct casdsk_disk *dsk, void *private);
-
-	/**
-	 * @brief Decrement exported object pending request counter.
-	 */
-	void (*pending_rq_dec)(struct casdsk_disk *dsk, void *private);
-
-	/**
-	 * @brief ioctl handler of exported object (top) block device.
-	 * Called by cas_disk when cas_disk device is in attached mode.
-	 */
-	int (*ioctl)(struct casdsk_disk *dsk, unsigned int cmd, unsigned long arg,
-		     void *private);
 };
 
 /**

From 62eb6dc3fd444e20c79ed005dbd8940cc52addc4 Mon Sep 17 00:00:00 2001
From: Robert Baldyga <robert.baldyga@intel.com>
Date: Tue, 27 Apr 2021 10:05:35 +0200
Subject: [PATCH 7/9] Remove unused functions from top volume

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 modules/cas_cache/volume/vol_block_dev_top.c | 46 ++++----------------
 modules/cas_cache/volume/vol_block_dev_top.h |  4 --
 2 files changed, 9 insertions(+), 41 deletions(-)

diff --git a/modules/cas_cache/volume/vol_block_dev_top.c b/modules/cas_cache/volume/vol_block_dev_top.c
index e8d33b1..b391dc5 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.c
+++ b/modules/cas_cache/volume/vol_block_dev_top.c
@@ -424,17 +424,6 @@ int block_dev_activate_exported_object(ocf_core_t core)
 	return ret;
 }
 
-static int _block_dev_activate_exported_object(ocf_core_t core, void *cntx)
-{
-	return block_dev_activate_exported_object(core);
-}
-
-int block_dev_activate_all_exported_objects(ocf_cache_t cache)
-{
-	return ocf_core_visit(cache, _block_dev_activate_exported_object, NULL,
-			true);
-}
-
 static const char *get_cache_id_string(ocf_cache_t cache)
 {
 	return ocf_cache_get_name(cache) + sizeof("cache") - 1;
@@ -496,17 +485,6 @@ end:
 	return result;
 }
 
-static int _block_dev_create_exported_object_visitor(ocf_core_t core, void *cntx)
-{
-	return block_dev_create_exported_object(core);
-}
-
-int block_dev_create_all_exported_objects(ocf_cache_t cache)
-{
-	return ocf_core_visit(cache, _block_dev_create_exported_object_visitor, NULL,
-			true);
-}
-
 int block_dev_destroy_exported_object(ocf_core_t core)
 {
 	int ret = 0;
@@ -594,6 +572,15 @@ static int _block_dev_stop_exported_object(ocf_core_t core, void *cntx)
 	return 0;
 }
 
+static int _block_dev_free_exported_object(ocf_core_t core, void *cntx)
+{
+	struct bd_object *bvol = bd_object(
+			ocf_core_get_volume(core));
+
+	casdisk_functions.casdsk_exp_obj_free(bvol->dsk);
+	return 0;
+}
+
 int block_dev_destroy_all_exported_objects(ocf_cache_t cache)
 {
 	int result;
@@ -610,21 +597,6 @@ int block_dev_destroy_all_exported_objects(ocf_cache_t cache)
 
 	ocf_core_visit(cache, _block_dev_stop_exported_object, NULL, true);
 
-	block_dev_free_all_exported_objects(cache);
-	return 0;
-}
-
-static int _block_dev_free_exported_object(ocf_core_t core, void *cntx)
-{
-	struct bd_object *bvol = bd_object(
-			ocf_core_get_volume(core));
-
-	casdisk_functions.casdsk_exp_obj_free(bvol->dsk);
-	return 0;
-}
-
-int block_dev_free_all_exported_objects(ocf_cache_t cache)
-{
 	return ocf_core_visit(cache, _block_dev_free_exported_object, NULL,
 			true);
 }
diff --git a/modules/cas_cache/volume/vol_block_dev_top.h b/modules/cas_cache/volume/vol_block_dev_top.h
index c4fcc86..e16bb8f 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.h
+++ b/modules/cas_cache/volume/vol_block_dev_top.h
@@ -6,15 +6,11 @@
 #ifndef __VOL_BLOCK_DEV_TOP_H__
 #define __VOL_BLOCK_DEV_TOP_H__
 
-int block_dev_activate_all_exported_objects(ocf_cache_t cache);
 int block_dev_activate_exported_object(ocf_core_t core);
 
-int block_dev_create_all_exported_objects(ocf_cache_t cache);
 int block_dev_create_exported_object(ocf_core_t core);
 
 int block_dev_destroy_all_exported_objects(ocf_cache_t cache);
 int block_dev_destroy_exported_object(ocf_core_t core);
 
-int block_dev_free_all_exported_objects(ocf_cache_t cache);
-
 #endif /* __VOL_BLOCK_DEV_TOP_H__ */

From 2d7b94fa2131144e8c0b0a1eddb0b37d96aa7655 Mon Sep 17 00:00:00 2001
From: Robert Baldyga <robert.baldyga@intel.com>
Date: Wed, 19 May 2021 23:47:56 +0200
Subject: [PATCH 8/9] Remove block_dev_start_bio()

Now submit_bio path has no fallback to request queue, so we can simplify
io accounting.

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 modules/cas_cache/volume/vol_block_dev_top.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/modules/cas_cache/volume/vol_block_dev_top.c b/modules/cas_cache/volume/vol_block_dev_top.c
index b391dc5..b4c179d 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.c
+++ b/modules/cas_cache/volume/vol_block_dev_top.c
@@ -45,13 +45,6 @@ static inline void _blockdev_end_io_acct(struct bio *bio,
 	cas_generic_end_io_acct(gd->queue, bio, &gd->part0, start_time);
 }
 
-void block_dev_start_bio(struct ocf_io *io)
-{
-	struct blk_data *data = ocf_io_get_data(io);
-	struct bio *bio = data->master_io_req;
-
-	data->start_time = _blockdev_start_io_acct(bio);
-}
 static inline int _blkdev_can_hndl_bio(struct bio *bio)
 {
 	if (CAS_CHECK_BARRIER(bio)) {
@@ -282,7 +275,7 @@ static void _blockdev_handle_data(ocf_core_t core, struct bio *bio)
 	}
 
 	ocf_io_set_cmpl(io, NULL, NULL, block_dev_complete_data);
-	ocf_io_set_start(io, block_dev_start_bio);
+	data->start_time = _blockdev_start_io_acct(bio);
 
 	ocf_core_submit_io(io);
 }

From e5e0697da46d6576dcbe20242c5e02206b059199 Mon Sep 17 00:00:00 2001
From: Robert Baldyga <robert.baldyga@intel.com>
Date: Fri, 21 May 2021 00:04:53 +0200
Subject: [PATCH 9/9] Add support for kernel 5.11

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 configure.d/1_bd_first_part.conf              | 74 ++++++++++++++++
 configure.d/1_bdev_lookup.conf                | 81 +++++++++++++++--
 configure.d/1_bdev_nr_sectors.conf            | 37 ++++++++
 configure.d/1_bdev_whole.conf                 | 37 ++++++++
 configure.d/1_bdget_disk.conf                 | 43 +++++++++
 ..._generic_acct.conf => 2_generic_acct.conf} | 87 ++++++++++---------
 configure.d/conf_framework                    |  1 +
 modules/cas_cache/layer_cache_management.c    | 25 +-----
 modules/cas_cache/volume/vol_blk_utils.c      |  2 +-
 .../cas_cache/volume/vol_block_dev_bottom.c   |  4 +-
 modules/cas_cache/volume/vol_block_dev_top.c  | 24 ++---
 modules/cas_disk/disk.c                       |  4 +-
 modules/cas_disk/exp_obj.c                    | 31 ++-----
 13 files changed, 333 insertions(+), 117 deletions(-)
 create mode 100644 configure.d/1_bd_first_part.conf
 create mode 100644 configure.d/1_bdev_nr_sectors.conf
 create mode 100644 configure.d/1_bdev_whole.conf
 create mode 100644 configure.d/1_bdget_disk.conf
 rename configure.d/{1_generic_acct.conf => 2_generic_acct.conf} (57%)

diff --git a/configure.d/1_bd_first_part.conf b/configure.d/1_bd_first_part.conf
new file mode 100644
index 0000000..d88f069
--- /dev/null
+++ b/configure.d/1_bd_first_part.conf
@@ -0,0 +1,74 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+check() {
+	cur_name=$(basename $2)
+	config_file_path=$1
+	if compile_module $cur_name "struct block_device *bd; bd->bd_partno;" "linux/blk_types.h"
+	then
+		echo $cur_name "1" >> $config_file_path
+	elif compile_module $cur_name "struct hd_struct *hd; hd->partno;" "linux/genhd.h"
+    then
+		echo $cur_name "2" >> $config_file_path
+	else
+		echo $cur_name "X" >> $config_file_path
+    fi
+}
+
+apply() {
+    case "$1" in
+    "1")
+		add_function "
+	static inline int cas_bd_get_next_part(struct block_device *bd)
+	{
+		int part_no = 0;
+		struct gendisk *disk = bd->bd_disk;
+		struct disk_part_iter piter;
+		struct block_device *part;
+
+		mutex_lock(&bd->bd_mutex);
+
+		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
+		while ((part = disk_part_iter_next(&piter))) {
+			part_no = part->bd_partno;
+			break;
+		}
+		disk_part_iter_exit(&piter);
+
+		mutex_unlock(&bd->bd_mutex);
+
+		return part_no;
+	}" ;;
+    "2")
+		add_function "
+	static inline int cas_bd_get_next_part(struct block_device *bd)
+	{
+		int part_no = 0;
+		struct gendisk *disk = bd->bd_disk;
+		struct disk_part_iter piter;
+		struct hd_struct *part;
+
+		mutex_lock(&bd->bd_mutex);
+
+		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
+		while ((part = disk_part_iter_next(&piter))) {
+			part_no = part->partno;
+			break;
+		}
+		disk_part_iter_exit(&piter);
+
+		mutex_unlock(&bd->bd_mutex);
+
+		return part_no;
+	}" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/1_bdev_lookup.conf b/configure.d/1_bdev_lookup.conf
index 51d49be..1d18a3f 100644
--- a/configure.d/1_bdev_lookup.conf
+++ b/configure.d/1_bdev_lookup.conf
@@ -9,12 +9,15 @@
 check() {
 	cur_name=$(basename $2)
 	config_file_path=$1
-    if compile_module $cur_name "lookup_bdev(\"some_path\")" "linux/fs.h" "linux/blkdev.h"
+    if compile_module $cur_name "dev_t dev; lookup_bdev(\"some_path\", &dev)" "linux/blkdev.h"
     then
         echo $cur_name "1" >> $config_file_path
-    elif compile_module $cur_name "lookup_bdev(\"some_path\", 0)" "linux/fs.h" "linux/blkdev.h"
+    elif compile_module $cur_name "lookup_bdev(\"some_path\")" "linux/fs.h" "linux/blkdev.h"
     then
         echo $cur_name "2" >> $config_file_path
+    elif compile_module $cur_name "lookup_bdev(\"some_path\", 0)" "linux/fs.h" "linux/blkdev.h"
+    then
+        echo $cur_name "3" >> $config_file_path
     else
         echo $cur_name "X" >> $config_file_path
     fi
@@ -23,11 +26,77 @@ check() {
 apply() {
     case "$1" in
     "1")
-        add_define "CAS_LOOKUP_BDEV(PATH) \\
-            lookup_bdev(PATH)" ;;
+        add_function "
+    static inline bool cas_bdev_exist(const char *path)
+    {
+        dev_t dev;
+        int result;
+
+        result = lookup_bdev(path, &dev);
+        return !result;
+    }"
+        add_function "
+    static inline bool cas_bdev_match(const char *path, struct block_device *bd)
+    {
+        dev_t dev;
+        int result;
+
+        result = lookup_bdev(path, &dev);
+        if (result)
+            return false;
+
+        return (bd->bd_dev == dev);
+    }" ;;
     "2")
-        add_define "CAS_LOOKUP_BDEV(PATH) \\
-            lookup_bdev(PATH, 0)" ;;
+        add_function "
+    static inline bool cas_bdev_exist(const char *path)
+    {
+        struct block_device *bdev;
+
+        bdev = lookup_bdev(path);
+        if (IS_ERR(bdev))
+            return false;
+        bdput(bdev);
+        return true;
+    }"
+        add_function "
+    static inline bool cas_bdev_match(const char *path, struct block_device *bd)
+    {
+        struct block_device *bdev;
+        bool match = false;
+
+        bdev = lookup_bdev(path);
+        if (IS_ERR(bdev))
+            return false;
+        match = (bdev == bd);
+        bdput(bdev);
+        return match;
+    }" ;;
+    "3")
+        add_function "
+    static inline bool cas_bdev_exist(const char *path)
+    {
+        struct block_device *bdev;
+
+        bdev = lookup_bdev(path, 0);
+        if (IS_ERR(bdev))
+            return false;
+        bdput(bdev);
+        return true;
+    }"
+        add_function "
+    static inline bool cas_bdev_match(const char *path, struct block_device *bd)
+    {
+        struct block_device *bdev;
+        bool match = false;
+
+        bdev = lookup_bdev(path, 0);
+        if (IS_ERR(bdev))
+            return false;
+        match = (bdev == bd);
+        bdput(bdev);
+        return match;
+    }" ;;
     *)
         exit 1
     esac
diff --git a/configure.d/1_bdev_nr_sectors.conf b/configure.d/1_bdev_nr_sectors.conf
new file mode 100644
index 0000000..33ccae7
--- /dev/null
+++ b/configure.d/1_bdev_nr_sectors.conf
@@ -0,0 +1,37 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+
+check() {
+	cur_name=$(basename $2)
+	config_file_path=$1
+    if compile_module $cur_name "bdev_nr_sectors(NULL);" "linux/genhd.h"
+    then
+        echo $cur_name 1 >> $config_file_path
+    elif compile_module $cur_name "struct block_device *bd; bd->bd_part->nr_sects;" "linux/blk_types.h"
+    then
+        echo $cur_name 2 >> $config_file_path
+    else
+        echo $cur_name X >> $config_file_path
+    fi
+}
+
+apply() {
+    case "$1" in
+    "1")
+        add_define "cas_bdev_nr_sectors(bd) \\
+            bdev_nr_sectors(bd)" ;;
+    "2")
+        add_define "cas_bdev_nr_sectors(bd) \\
+            (bd->bd_part->nr_sects)" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/1_bdev_whole.conf b/configure.d/1_bdev_whole.conf
new file mode 100644
index 0000000..b8981e8
--- /dev/null
+++ b/configure.d/1_bdev_whole.conf
@@ -0,0 +1,37 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+
+check() {
+	cur_name=$(basename $2)
+	config_file_path=$1
+    if compile_module $cur_name "struct block_device *bd; bdev_whole(bd);" "linux/blk_types.h" "linux/genhd.h"
+    then
+        echo $cur_name 1 >> $config_file_path
+    elif compile_module $cur_name "struct block_device *bd; bd->bd_contains;" "linux/blk_types.h"
+    then
+        echo $cur_name 2 >> $config_file_path
+    else
+        echo $cur_name X >> $config_file_path
+    fi
+}
+
+apply() {
+    case "$1" in
+    "1")
+        add_define "cas_bdev_whole(bd) \\
+            bdev_whole(bd)" ;;
+    "2")
+        add_define "cas_bdev_whole(bd) \\
+            (bd->bd_contains)" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/1_bdget_disk.conf b/configure.d/1_bdget_disk.conf
new file mode 100644
index 0000000..fbd2227
--- /dev/null
+++ b/configure.d/1_bdget_disk.conf
@@ -0,0 +1,43 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+
+check() {
+	cur_name=$(basename $2)
+	config_file_path=$1
+    if compile_module $cur_name "bdget_disk(NULL, 0);" "linux/genhd.h"
+    then
+        echo $cur_name 1 >> $config_file_path
+    elif compile_module $cur_name "bdgrab(NULL);" "linux/blkdev.h"
+    then
+        echo $cur_name 2 >> $config_file_path
+    else
+        echo $cur_name X >> $config_file_path
+    fi
+}
+
+apply() {
+    case "$1" in
+    "1")
+        add_function "
+        static inline struct block_device *cas_bdget_disk(struct gendisk *gd)
+        {
+            return bdget_disk(gd, 0);
+        }" ;;
+    "2")
+        add_function "
+        static inline struct block_device *cas_bdget_disk(struct gendisk *gd)
+        {
+            return bdgrab(gd->part0);
+        }" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/1_generic_acct.conf b/configure.d/2_generic_acct.conf
similarity index 57%
rename from configure.d/1_generic_acct.conf
rename to configure.d/2_generic_acct.conf
index a8afcfb..1b97789 100644
--- a/configure.d/1_generic_acct.conf
+++ b/configure.d/2_generic_acct.conf
@@ -34,56 +34,62 @@ apply() {
     "1")
         add_function "
         static inline unsigned long long cas_generic_start_io_acct(
-                struct request_queue *q, struct bio *bio,
-                struct hd_struct *part)
+                struct bio *bio)
         {
             return bio_start_io_acct(bio);
         }"
     add_function "
-        static inline void cas_generic_end_io_acct(struct request_queue *q,
-                struct bio *bio, struct hd_struct *part,
-                unsigned long start_time)
+        static inline void cas_generic_end_io_acct(
+                struct bio *bio, unsigned long start_time)
         {
             bio_end_io_acct(bio, start_time);
         }" ;;
     "2")
         add_function "
         static inline unsigned long long cas_generic_start_io_acct(
-                struct request_queue *q, struct bio *bio,
-                struct hd_struct *part)
+                struct bio *bio)
         {
-            generic_start_io_acct(q, bio_data_dir(bio), bio_sectors(bio), part);
+            struct gendisk *gd = CAS_BIO_GET_DEV(bio);
+
+            generic_start_io_acct(gd->queue, bio_data_dir(bio),
+                    bio_sectors(bio), &gd->part0);
             return jiffies;
         }"
     add_function "
-        static inline void cas_generic_end_io_acct(struct request_queue *q,
-                struct bio *bio, struct hd_struct *part,
-                unsigned long start_time)
+        static inline void cas_generic_end_io_acct(
+                struct bio *bio, unsigned long start_time)
         {
-            generic_end_io_acct(q, bio_data_dir(bio), part, start_time);
+            struct gendisk *gd = CAS_BIO_GET_DEV(bio);
+
+            generic_end_io_acct(gd->queue, bio_data_dir(bio),
+                    &gd->part0, start_time);
         }" ;;
     "3")
         add_function "
         static inline unsigned long long cas_generic_start_io_acct(
-                struct request_queue *q, struct bio *bio,
-                struct hd_struct *part)
+                struct bio *bio)
         {
-            generic_start_io_acct(bio_data_dir(bio), bio_sectors(bio), part);
+            struct gendisk *gd = CAS_BIO_GET_DEV(bio);
+
+            generic_start_io_acct(bio_data_dir(bio), bio_sectors(bio),
+                    &gd->part0);
             return jiffies;
         }"
     add_function "
-        static inline void cas_generic_end_io_acct(struct request_queue *q,
-                struct bio *bio, struct hd_struct *part,
-                unsigned long start_time)
+        static inline void cas_generic_end_io_acct(
+                struct bio *bio, unsigned long start_time)
         {
-            generic_end_io_acct(bio_data_dir(bio), part, start_time);
+            struct gendisk *gd = CAS_BIO_GET_DEV(bio);
+
+            generic_end_io_acct(bio_data_dir(bio), &gd->part0, start_time);
         }" ;;
     "4")
         add_function "
         static inline unsigned long long cas_generic_start_io_acct(
-                struct request_queue *q, struct bio *bio,
-                struct hd_struct *part)
+                struct bio *bio)
         {
+            struct gendisk *gd = CAS_BIO_GET_DEV(bio);
+
             int rw = bio_data_dir(bio);
             int cpu = part_stat_lock();
             part_round_stats(cpu, part);
@@ -94,44 +100,47 @@ apply() {
             return jiffies;
         }"
     add_function "
-        static inline void cas_generic_end_io_acct(struct request_queue *q,
-                struct bio *bio, struct hd_struct *part,
-                unsigned long start_time)
+        static inline void cas_generic_end_io_acct(
+                struct bio *bio, unsigned long start_time)
         {
+            struct gendisk *gd = CAS_BIO_GET_DEV(bio);
+
             int rw = bio_data_dir(bio);
             unsigned long duration = jiffies - start_time;
             int cpu = part_stat_lock();
-            part_stat_add(cpu, part, ticks[rw], duration);
-            part_round_stats(cpu, part);
-            part_dec_in_flight(part, rw);
+            part_stat_add(cpu, &gd->part0, ticks[rw], duration);
+            part_round_stats(cpu, &gd->part0);
+            part_dec_in_flight(&gd->part0, rw);
             part_stat_unlock();
         }" ;;
     "5")
         add_function "
         static inline unsigned long long cas_generic_start_io_acct(
-                struct request_queue *q, struct bio *bio,
-                struct hd_struct *part)
+                struct bio *bio)
         {
+            struct gendisk *gd = CAS_BIO_GET_DEV(bio);
+
             int rw = bio_data_dir(bio);
             int cpu = part_stat_lock();
-            part_round_stats(NULL, cpu, part);
-            part_stat_inc(cpu, part, ios[rw]);
-            part_stat_add(cpu, part, sectors[rw], bio_sectors(bio));
-            part_inc_in_flight(NULL, part, rw);
+            part_round_stats(NULL, cpu, &gd->part0);
+            part_stat_inc(cpu, &gd->part0, ios[rw]);
+            part_stat_add(cpu, &gd->part0, sectors[rw], bio_sectors(bio));
+            part_inc_in_flight(NULL, &gd->part0, rw);
             part_stat_unlock();
             return jiffies;
         }"
     add_function "
-        static inline void cas_generic_end_io_acct(struct request_queue *q,
-                struct bio *bio, struct hd_struct *part,
-                unsigned long start_time)
+        static inline void cas_generic_end_io_acct(
+                struct bio *bio, unsigned long start_time)
         {
+            struct gendisk *gd = CAS_BIO_GET_DEV(bio);
+
             int rw = bio_data_dir(bio);
             unsigned long duration = jiffies - start_time;
             int cpu = part_stat_lock();
-            part_stat_add(cpu, part, ticks[rw], duration);
-            part_round_stats(NULL, cpu, part);
-            part_dec_in_flight(NULL, part, rw);
+            part_stat_add(cpu, &gd->part0, ticks[rw], duration);
+            part_round_stats(NULL, cpu, &gd->part0);
+            part_dec_in_flight(NULL, &gd->part0, rw);
             part_stat_unlock();
         }" ;;
     *)
diff --git a/configure.d/conf_framework b/configure.d/conf_framework
index 40d0581..de79b4e 100644
--- a/configure.d/conf_framework
+++ b/configure.d/conf_framework
@@ -52,6 +52,7 @@ compile_module(){
 		return 0;
 	}
 	void cleanup_module(void) {};
+    MODULE_LICENSE("GPL");
 	EOF
 	#######################################
 
diff --git a/modules/cas_cache/layer_cache_management.c b/modules/cas_cache/layer_cache_management.c
index 0198486..8d8ae0a 100644
--- a/modules/cas_cache/layer_cache_management.c
+++ b/modules/cas_cache/layer_cache_management.c
@@ -1068,7 +1068,6 @@ out_bdev:
 int cache_mngt_prepare_core_cfg(struct ocf_mngt_core_config *cfg,
 		struct kcas_insert_core *cmd_info)
 {
-	struct block_device *bdev;
 	char core_name[OCF_CORE_NAME_SIZE] = {};
 	ocf_cache_t cache;
 	uint16_t core_id;
@@ -1109,10 +1108,8 @@ int cache_mngt_prepare_core_cfg(struct ocf_mngt_core_config *cfg,
 		return 0;
 	}
 
-	bdev = CAS_LOOKUP_BDEV(cfg->uuid.data);
-	if (IS_ERR(bdev))
+	if (!cas_bdev_exist(cfg->uuid.data))
 		return -OCF_ERR_INVAL_VOLUME_TYPE;
-	bdput(bdev);
 
 	if (cmd_info->update_path)
 		return 0;
@@ -1135,9 +1132,7 @@ static int cache_mngt_update_core_uuid(ocf_cache_t cache, const char *core_name,
 {
 	ocf_core_t core;
 	ocf_volume_t vol;
-	struct block_device *bdev;
 	struct bd_object *bdvol;
-	bool match;
 	int result;
 
 	if (ocf_core_get_by_name(cache, core_name, name_len, &core)) {
@@ -1154,19 +1149,7 @@ static int cache_mngt_update_core_uuid(ocf_cache_t cache, const char *core_name,
 	vol = ocf_core_get_volume(core);
 	bdvol = bd_object(vol);
 
-	/* lookup block device object for device pointed by uuid */
-	bdev =  CAS_LOOKUP_BDEV(uuid->data);
-	if (IS_ERR(bdev)) {
-		printk(KERN_ERR "failed to lookup bdev%s\n", (char*)uuid->data);
-		return -ENODEV;
-	}
-
-	/* check whether both core id and uuid point to the same block device */
-	match = (bdvol->btm_bd == bdev);
-
-	bdput(bdev);
-
-	if (!match) {
+	if (!cas_bdev_match(uuid->data, bdvol->btm_bd)) {
 		printk(KERN_ERR "UUID provided does not match target core device\n");
 		return -ENODEV;
 	}
@@ -1766,7 +1749,7 @@ int cache_mngt_prepare_cache_cfg(struct ocf_mngt_cache_config *cfg,
 				-OCF_ERR_INVAL_VOLUME_TYPE;
 	}
 
-	is_part = (bdev->bd_contains != bdev);
+	is_part = (cas_bdev_whole(bdev) != bdev);
 	part_count = cas_blk_get_part_count(bdev);
 	blkdev_put(bdev, (FMODE_EXCL|FMODE_READ));
 
@@ -1872,7 +1855,7 @@ static void init_instance_complete(struct _cache_mngt_attach_context *ctx,
 	bdev = bd_cache_obj->btm_bd;
 
 	/* If we deal with whole device, reread partitions */
-	if (bdev->bd_contains == bdev)
+	if (cas_bdev_whole(bdev) == bdev)
 		cas_reread_partitions(bdev);
 
 	/* Set other back information */
diff --git a/modules/cas_cache/volume/vol_blk_utils.c b/modules/cas_cache/volume/vol_blk_utils.c
index 55ad827..74cae21 100644
--- a/modules/cas_cache/volume/vol_blk_utils.c
+++ b/modules/cas_cache/volume/vol_blk_utils.c
@@ -303,7 +303,7 @@ int cas_blk_identify_type_by_bdev(struct block_device *bdev,
 		atomic_params_int.is_mode_optimal = 1;
 		break;
 #else
-		if (bdev == bdev->bd_contains) {
+		if (bdev == cas_bdev_whole(bdev)) {
 			/*
 			 * Entire device - format isn't optimal
 			 */
diff --git a/modules/cas_cache/volume/vol_block_dev_bottom.c b/modules/cas_cache/volume/vol_block_dev_bottom.c
index 949b66e..8777a17 100644
--- a/modules/cas_cache/volume/vol_block_dev_bottom.c
+++ b/modules/cas_cache/volume/vol_block_dev_bottom.c
@@ -84,9 +84,9 @@ uint64_t block_dev_get_byte_length(ocf_volume_t vol)
 	struct block_device *bd = bdobj->btm_bd;
 	uint64_t sector_length;
 
-	sector_length = (bd->bd_contains == bd) ?
+	sector_length = (cas_bdev_whole(bd) == bd) ?
 			get_capacity(bd->bd_disk) :
-			bd->bd_part->nr_sects;
+			cas_bdev_nr_sectors(bd);
 
 	return sector_length << SECTOR_SHIFT;
 }
diff --git a/modules/cas_cache/volume/vol_block_dev_top.c b/modules/cas_cache/volume/vol_block_dev_top.c
index b4c179d..cb7133c 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.c
+++ b/modules/cas_cache/volume/vol_block_dev_top.c
@@ -30,21 +30,6 @@ static void _blockdev_set_bio_data(struct blk_data *data, struct bio *bio)
 #endif
 }
 
-static inline unsigned long long _blockdev_start_io_acct(struct bio *bio)
-{
-	struct gendisk *gd = CAS_BIO_GET_DEV(bio);
-
-	return cas_generic_start_io_acct(gd->queue, bio, &gd->part0);
-}
-
-static inline void _blockdev_end_io_acct(struct bio *bio,
-		unsigned long start_time)
-{
-	struct gendisk *gd = CAS_BIO_GET_DEV(bio);
-
-	cas_generic_end_io_acct(gd->queue, bio, &gd->part0, start_time);
-}
-
 static inline int _blkdev_can_hndl_bio(struct bio *bio)
 {
 	if (CAS_CHECK_BARRIER(bio)) {
@@ -140,7 +125,7 @@ static int _blockdev_set_geometry(struct casdsk_disk *dsk, void *private)
 	cache_bd = casdisk_functions.casdsk_disk_get_blkdev(bd_cache_vol->dsk);
 	BUG_ON(!cache_bd);
 
-	core_q = core_bd->bd_contains->bd_disk->queue;
+	core_q = cas_bdev_whole(core_bd)->bd_disk->queue;
 	cache_q = cache_bd->bd_disk->queue;
 	exp_q = casdisk_functions.casdsk_exp_obj_get_queue(dsk);
 
@@ -215,7 +200,7 @@ static void block_dev_complete_data(struct ocf_io *io, int error)
 	struct blk_data *data = ocf_io_get_data(io);
 	struct bio *bio = data->master_io_req;
 
-	_blockdev_end_io_acct(bio, data->start_time);
+	cas_generic_end_io_acct(bio, data->start_time);
 
 	CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(error));
 	ocf_io_put(io);
@@ -275,7 +260,7 @@ static void _blockdev_handle_data(ocf_core_t core, struct bio *bio)
 	}
 
 	ocf_io_set_cmpl(io, NULL, NULL, block_dev_complete_data);
-	data->start_time = _blockdev_start_io_acct(bio);
+	data->start_time = cas_generic_start_io_acct(bio);
 
 	ocf_core_submit_io(io);
 }
@@ -296,7 +281,8 @@ static void _blockdev_handle_discard(ocf_core_t core, struct bio *bio)
 
 	io = ocf_core_new_io(core, cache_priv->io_queues[smp_processor_id()],
 			CAS_BIO_BISECTOR(bio) << SECTOR_SHIFT,
-			CAS_BIO_BISIZE(bio), OCF_WRITE, 0, 0);
+			CAS_BIO_BISIZE(bio), OCF_WRITE, 0,
+			CAS_CLEAR_FLUSH(CAS_BIO_OP_FLAGS(bio)));
 
 	if (!io) {
 		CAS_PRINT_RL(KERN_CRIT
diff --git a/modules/cas_disk/disk.c b/modules/cas_disk/disk.c
index f9e2708..3007e8b 100644
--- a/modules/cas_disk/disk.c
+++ b/modules/cas_disk/disk.c
@@ -281,9 +281,7 @@ struct request_queue *casdsk_disk_get_queue(struct casdsk_disk *dsk)
 {
 	BUG_ON(!dsk);
 	BUG_ON(!dsk->bd);
-	BUG_ON(!dsk->bd->bd_contains);
-	BUG_ON(!dsk->bd->bd_contains->bd_disk);
-	return dsk->bd->bd_contains->bd_disk->queue;
+	return cas_bdev_whole(dsk->bd)->bd_disk->queue;
 }
 EXPORT_SYMBOL(casdsk_disk_get_queue);
 
diff --git a/modules/cas_disk/exp_obj.c b/modules/cas_disk/exp_obj.c
index fee97fa..19f7b31 100644
--- a/modules/cas_disk/exp_obj.c
+++ b/modules/cas_disk/exp_obj.c
@@ -189,27 +189,6 @@ static MAKE_RQ_RET_TYPE _casdsk_exp_obj_make_rq_fn(struct request_queue *q,
 	return _casdsk_exp_obj_submit_bio(bio);
 }
 
-static int _casdsk_get_next_part_no(struct block_device *bd)
-{
-	int part_no = 0;
-	struct gendisk *disk = bd->bd_disk;
-	struct disk_part_iter piter;
-	struct hd_struct *part;
-
-	mutex_lock(&bd->bd_mutex);
-
-	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
-	while ((part = disk_part_iter_next(&piter))) {
-		part_no = part->partno;
-		break;
-	}
-	disk_part_iter_exit(&piter);
-
-	mutex_unlock(&bd->bd_mutex);
-
-	return part_no;
-}
-
 static int _casdsk_del_partitions(struct casdsk_disk *dsk)
 {
 	struct block_device *bd = casdsk_disk_get_blkdev(dsk);
@@ -249,7 +228,7 @@ static int _casdsk_del_partitions(struct casdsk_disk *dsk)
 		goto out_copy;
 	}
 
-	while ((part_no = _casdsk_get_next_part_no(bd))) {
+	while ((part_no = cas_bd_get_next_part(bd))) {
 		bpart.pno = part_no;
 		result = copy_to_user((void __user *)usr_bpart, &bpart,
 				sizeof(bpart));
@@ -288,7 +267,7 @@ static int _casdsk_exp_obj_hide_parts(struct casdsk_disk *dsk)
 	struct block_device *bd = casdsk_disk_get_blkdev(dsk);
 	struct gendisk *gdsk = casdsk_disk_get_gendisk(dsk);
 
-	if (bd != bd->bd_contains)
+	if (bd != cas_bdev_whole(bd))
 		/* It is partition, no more job required */
 		return 0;
 
@@ -325,7 +304,7 @@ static int _casdsk_exp_obj_set_dev_t(struct casdsk_disk *dsk, struct gendisk *gd
 	bdev = casdsk_disk_get_blkdev(dsk);
 	BUG_ON(!bdev);
 
-	if (bdev->bd_contains != bdev) {
+	if (cas_bdev_whole(bdev) != bdev) {
 		minors = 1;
 		flags = 0;
 	} else {
@@ -352,7 +331,7 @@ static void _casdsk_exp_obj_clear_dev_t(struct casdsk_disk *dsk)
 	struct block_device *bdev = casdsk_disk_get_blkdev(dsk);
 	struct gendisk *gdsk = casdsk_disk_get_gendisk(dsk);
 
-	if (bdev->bd_contains == bdev) {
+	if (cas_bdev_whole(bdev) == bdev) {
 		/* Restore previous configuration of bottom disk */
 		gdsk->minors = dsk->gd_minors;
 		gdsk->flags |= dsk->gd_flags;
@@ -718,7 +697,7 @@ int casdsk_exp_obj_lock(struct casdsk_disk *dsk)
 
 	exp_obj = dsk->exp_obj;
 
-	exp_obj->locked_bd = bdget_disk(exp_obj->gd, 0);
+	exp_obj->locked_bd = cas_bdget_disk(exp_obj->gd);
 	if (!exp_obj->locked_bd)
 		return -ENAVAIL;