From 1771228a4646732f690b0a1bd2271763522790d1 Mon Sep 17 00:00:00 2001
From: Michal Mielewczyk <michal.mielewczyk@intel.com>
Date: Wed, 20 Feb 2019 17:05:39 -0500
Subject: [PATCH 1/2] Removed starting cache from load

Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
---
 src/mngt/ocf_mngt_cache.c | 20 +-------------------
 1 file changed, 1 insertion(+), 19 deletions(-)

diff --git a/src/mngt/ocf_mngt_cache.c b/src/mngt/ocf_mngt_cache.c
index 663c1d3..f230be3 100644
--- a/src/mngt/ocf_mngt_cache.c
+++ b/src/mngt/ocf_mngt_cache.c
@@ -1635,35 +1635,17 @@ static void _ocf_mngt_cache_load_log(ocf_cache_t cache)
 }
 
 int ocf_mngt_cache_load(ocf_ctx_t ctx, ocf_cache_t *cache,
-		struct ocf_mngt_cache_config *cfg,
 		struct ocf_mngt_cache_device_config *device_cfg)
 {
 	int result;
 
-	if (!ctx || !cache || !cfg || !device_cfg)
+	if (!ctx || !cache || !device_cfg)
 		return -OCF_ERR_INVAL;
 
-	result = _ocf_mngt_cache_validate_cfg(cfg);
-	if (result)
-		return result;
-
 	result = _ocf_mngt_cache_validate_device_cfg(device_cfg);
 	if (result)
 		return result;
 
-	result = _ocf_mngt_cache_start(ctx, cache, cfg);
-	if (!result) {
-		ocf_cache_log(*cache, log_info, "Successfully added\n");
-	} else {
-		if (cfg->name) {
-			ocf_log(ctx, log_err, "Inserting cache %s failed\n",
-					cfg->name);
-		} else {
-			ocf_log(ctx, log_err, "Inserting cache failed\n");
-		}
-		return result;
-	}
-
 	result =  _ocf_mngt_cache_attach(*cache, device_cfg, true);
 	if (result) {
 		_ocf_mngt_init_handle_error(*cache, ctx, NULL);

From e53944d472f8ee2fa69f6bdd23e5e1af8e7e60a4 Mon Sep 17 00:00:00 2001
From: Michal Mielewczyk <michal.mielewczyk@intel.com>
Date: Fri, 15 Feb 2019 08:12:00 -0500
Subject: [PATCH 2/2] Dynamic I/O queue management

- Queue allocation is now separated from starting cache.
- Queue can be created and destroyed in runtime.
- All queue ops accept queue handle instead of queue id.
- Cache stores queues as list instead of array.

Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
---
 example/simple/src/ctx.c                      | 45 ---------
 example/simple/src/main.c                     | 52 +++++++++-
 inc/ocf_cache.h                               | 12 ---
 inc/ocf_cleaner.h                             |  7 +-
 inc/ocf_ctx.h                                 | 51 ----------
 inc/ocf_io.h                                  | 10 +-
 inc/ocf_mngt.h                                |  7 --
 inc/ocf_queue.h                               | 75 ++++++++++++--
 inc/ocf_trace.h                               |  7 +-
 src/cleaning/acp.c                            |  2 +-
 src/cleaning/alru.c                           |  2 +-
 src/cleaning/cleaning.c                       | 21 ++--
 src/cleaning/cleaning.h                       |  2 +-
 src/engine/cache_engine.c                     | 12 ++-
 src/engine/engine_common.c                    | 21 ++--
 src/eviction/eviction.c                       |  4 +-
 src/eviction/eviction.h                       | 22 ++---
 src/eviction/lru.c                            | 36 +++----
 src/eviction/lru.h                            |  2 +-
 src/eviction/ops.h                            |  2 +-
 src/metadata/metadata_io.c                    | 26 ++---
 src/metadata/metadata_io.h                    | 22 ++---
 src/metadata/metadata_raw.c                   | 42 ++++----
 src/mngt/ocf_mngt_cache.c                     | 40 ++------
 src/mngt/ocf_mngt_common.c                    |  1 -
 src/ocf_cache_priv.h                          |  3 +-
 src/ocf_core.c                                | 26 ++---
 src/ocf_ctx_priv.h                            | 19 ----
 src/ocf_queue.c                               | 98 +++++++------------
 src/ocf_queue_priv.h                          | 23 +++--
 src/ocf_request.h                             |  6 +-
 src/ocf_trace.c                               | 29 +++---
 src/ocf_trace_priv.h                          | 28 +++---
 src/utils/utils_cleaner.c                     |  6 +-
 src/utils/utils_cleaner.h                     |  2 +-
 src/utils/utils_req.c                         | 30 +++---
 src/utils/utils_req.h                         | 24 ++---
 .../cleaning.c/ocf_cleaner_run_test.c         |  7 +-
 38 files changed, 379 insertions(+), 445 deletions(-)

diff --git a/example/simple/src/ctx.c b/example/simple/src/ctx.c
index d53d665..6baea83 100644
--- a/example/simple/src/ctx.c
+++ b/example/simple/src/ctx.c
@@ -134,42 +134,6 @@ static void ctx_data_secure_erase(ctx_data_t *ctx_data)
 {
 }
 
-/*
- * Initialize queue thread. To keep this example simple we handle queues
- * synchronously, thus it's left non-implemented.
- */
-static int ctx_queue_init(ocf_queue_t q)
-{
-	return 0;
-}
-
-/*
- * Trigger queue asynchronously. Made synchronous for simplicity.
- */
-static inline void ctx_queue_kick_async(ocf_queue_t q)
-{
-	ocf_queue_run(q);
-}
-
-/*
- * Trigger queue synchronously. May be implemented as asynchronous as well,
- * but in some environments kicking queue synchronously may reduce latency,
- * so to take advantage of such situations OCF call synchronous variant of
- * queue kick callback where possible.
- */
-static void ctx_queue_kick_sync(ocf_queue_t q)
-{
-	ocf_queue_run(q);
-}
-
-/*
- * Stop queue thread. To keep this example simple we handle queues
- * synchronously, thus it's left non-implemented.
- */
-static void ctx_queue_stop(ocf_queue_t q)
-{
-}
-
 /*
  * Initialize cleaner thread. Cleaner thread is left non-implemented,
  * to keep this example as simple as possible.
@@ -257,8 +221,6 @@ static int ctx_logger_dump_stack(ocf_logger_t logger)
  * This structure describes context config, containing simple context info
  * and pointers to ops callbacks. Ops are splitted into few categories:
  * - data ops, providing context specific data handing interface,
- * - queue ops, providing interface for starting, stoping and kicking
- *   queue thread in both synchronous and asynchronous way,
  * - cleaner ops, providing interface to start and stop clener thread,
  * - metadata updater ops, providing interface for starting, stoping
  *   and kicking metadata updater thread.
@@ -280,13 +242,6 @@ static const struct ocf_ctx_config ctx_cfg = {
 			.secure_erase = ctx_data_secure_erase,
 		},
 
-		.queue = {
-			.init = ctx_queue_init,
-			.kick_sync = ctx_queue_kick_sync,
-			.kick = ctx_queue_kick_async,
-			.stop = ctx_queue_stop,
-		},
-
 		.cleaner = {
 			.init = ctx_cleaner_init,
 			.stop = ctx_cleaner_stop,
diff --git a/example/simple/src/main.c b/example/simple/src/main.c
index 4ff4328..4360829 100644
--- a/example/simple/src/main.c
+++ b/example/simple/src/main.c
@@ -18,6 +18,44 @@ void error(char *msg)
 	exit(1);
 }
 
+/*
+ * Trigger queue asynchronously. Made synchronous for simplicity.
+ */
+static inline void queue_kick_async(ocf_queue_t q)
+{
+	ocf_queue_run(q);
+}
+
+/*
+ * Trigger queue synchronously. May be implemented as asynchronous as well,
+ * but in some environments kicking queue synchronously may reduce latency,
+ * so to take advantage of such situations OCF call synchronous variant of
+ * queue kick callback where possible.
+ */
+static void queue_kick_sync(ocf_queue_t q)
+{
+	ocf_queue_run(q);
+}
+
+/*
+ * Stop queue thread. To keep this example simple we handle queues
+ * synchronously, thus it's left non-implemented.
+ */
+static void queue_stop(ocf_queue_t q)
+{
+}
+
+/*
+ * Queue ops providing interface for running queue thread in both synchronous
+ * and asynchronous way. The stop() operation in called just before queue is
+ * being destroyed.
+ */
+const struct ocf_queue_ops queue_ops = {
+	.kick_sync = queue_kick_sync,
+	.kick = queue_kick_async,
+	.stop = queue_stop,
+};
+
 /*
  * Function starting cache and attaching cache device.
  */
@@ -25,6 +63,7 @@ int initialize_cache(ocf_ctx_t ctx, ocf_cache_t *cache)
 {
 	struct ocf_mngt_cache_config cache_cfg = { };
 	struct ocf_mngt_cache_device_config device_cfg = { };
+	ocf_queue_t queue;
 	int ret;
 
 	/* Cache configuration */
@@ -33,7 +72,6 @@ int initialize_cache(ocf_ctx_t ctx, ocf_cache_t *cache)
 	cache_cfg.cache_line_size = ocf_cache_line_size_4;
 	cache_cfg.cache_mode = ocf_cache_mode_wt;
 	cache_cfg.metadata_volatile = true;
-	cache_cfg.io_queues = 1;
 	cache_cfg.name = "cache1";
 
 	/* Cache deivce (volume) configuration */
@@ -48,6 +86,14 @@ int initialize_cache(ocf_ctx_t ctx, ocf_cache_t *cache)
 	if (ret)
 		return ret;
 
+	ret = ocf_queue_create(*cache, &queue, &queue_ops);
+	if (!queue) {
+		ocf_mngt_cache_stop(*cache);
+		return -ENOMEM;
+	}
+
+	ocf_cache_set_priv(*cache, queue);
+
 	/* Attach volume to cache */
 	ret = ocf_mngt_cache_attach(*cache, &device_cfg);
 	if (ret) {
@@ -113,6 +159,8 @@ int submit_io(ocf_core_t core, struct volume_data *data,
 		uint64_t addr, uint64_t len, int dir, ocf_end_io_t cmpl)
 {
 	struct ocf_io *io;
+	ocf_cache_t cache = ocf_core_get_cache(core);
+	ocf_queue_t queue = (ocf_queue_t)ocf_cache_get_priv(cache);
 
 	/* Allocate new io */
 	io = ocf_core_new_io(core);
@@ -123,6 +171,8 @@ int submit_io(ocf_core_t core, struct volume_data *data,
 	ocf_io_configure(io, addr, len, dir, 0, 0);
 	/* Assign data to io */
 	ocf_io_set_data(io, data, 0);
+	/* Setup io queue to */
+	ocf_io_set_queue(io, queue);
 	/* Setup completion function */
 	ocf_io_set_cmpl(io, NULL, NULL, cmpl);
 	/* Submit io */
diff --git a/inc/ocf_cache.h b/inc/ocf_cache.h
index c31d72b..b43bbde 100644
--- a/inc/ocf_cache.h
+++ b/inc/ocf_cache.h
@@ -109,18 +109,6 @@ ocf_volume_t ocf_cache_get_volume(ocf_cache_t cache);
  */
 ocf_cache_id_t ocf_cache_get_id(ocf_cache_t cache);
 
-/**
- * @brief Get queue object associated with cache
- *
- * @param[in] cache Cache object
- * @param[in] id Queue id
- * @param[out] q Queue object
- *
- * @retval 0 Success
- * @retval Non-zero Fail
- */
-int ocf_cache_get_queue(ocf_cache_t cache, unsigned id, ocf_queue_t *q);
-
 /**
  * @brief Set name of given cache object
  *
diff --git a/inc/ocf_cleaner.h b/inc/ocf_cleaner.h
index 42c218b..6d849fa 100644
--- a/inc/ocf_cleaner.h
+++ b/inc/ocf_cleaner.h
@@ -34,16 +34,17 @@ void ocf_cleaner_set_cmpl(ocf_cleaner_t cleaner, ocf_cleaner_end_t fn);
  * @brief Set cleaner queue
  *
  * @param[in] cleaner Cleaner instance
- * @param[in] io_queue Queue number
+ * @param[in] io_queue Queue handle
  */
-void ocf_cleaner_set_io_queue(ocf_cleaner_t cleaner, uint32_t io_queue);
+void ocf_cleaner_set_io_queue(ocf_cleaner_t cleaner, ocf_queue_t io_queue);
 
 /**
  * @brief Run cleaner
  *
  * @param[in] c Cleaner instance to run
+ * @param[in] queue IO queue handle
  */
-void ocf_cleaner_run(ocf_cleaner_t c);
+void ocf_cleaner_run(ocf_cleaner_t c, ocf_queue_t queue);
 
 /**
  * @brief Set cleaner private data
diff --git a/inc/ocf_ctx.h b/inc/ocf_ctx.h
index ba8c707..4ca4366 100644
--- a/inc/ocf_ctx.h
+++ b/inc/ocf_ctx.h
@@ -128,54 +128,6 @@ struct ocf_data_ops {
 	void (*secure_erase)(ctx_data_t *dst);
 };
 
-/**
- * @brief I/O queue operations
- */
-struct ocf_queue_ops {
-	/**
-	 * @brief Initialize I/O queue.
-	 *
-	 * This function should create worker, thread or any other queue
-	 * processing related stuff specific to given environment.
-	 *
-	 * @param[in] q I/O queue to be initialized
-	 *
-	 * @retval 0 I/O queue has been initializaed successfully
-	 * @retval Non-zero I/O queue initialization failure
-	 */
-	int (*init)(ocf_queue_t q);
-
-	/**
-	 * @brief Kick I/O queue processing
-	 *
-	 * This function should inform worker, thread or any other queue
-	 * processing mechanism, that there are new requests in queue to
-	 * be processed. Processing requests inside current call is not allowed.
-	 *
-	 * @param[in] q I/O queue to be kicked
-	 */
-	void (*kick)(ocf_queue_t q);
-
-	/**
-	 * @brief Kick I/O queue processing
-	 *
-	 * This function should inform worker, thread or any other queue
-	 * processing mechanism, that there are new requests in queue to
-	 * be processed. Kick function is allowed to process requests in current
-	 * call
-	 *
-	 * @param[in] q I/O queue to be kicked
-	 */
-	void (*kick_sync)(ocf_queue_t q);
-
-	/**
-	 * @brief Stop I/O queue
-	 *
-	 * @param[in] q I/O queue beeing stopped
-	 */
-	void (*stop)(ocf_queue_t q);
-};
-
 /**
  * @brief Cleaner operations
  */
@@ -243,9 +195,6 @@ struct ocf_ctx_ops {
 	/* Context data operations */
 	struct ocf_data_ops data;
 
-	/* Queue operations */
-	struct ocf_queue_ops queue;
-
 	/* Cleaner operations */
 	struct ocf_cleaner_ops cleaner;
 
diff --git a/inc/ocf_io.h b/inc/ocf_io.h
index 4162d6c..6892c46 100644
--- a/inc/ocf_io.h
+++ b/inc/ocf_io.h
@@ -84,9 +84,9 @@ struct ocf_io {
 	uint32_t dir;
 
 	/**
-	 * @brief Queue id
+	 * @brief Queue handle
 	 */
-	uint32_t io_queue;
+	ocf_queue_t io_queue;
 
 	/**
 	 * @brief OCF IO start function
@@ -258,12 +258,12 @@ static inline ctx_data_t *ocf_io_get_data(struct ocf_io *io)
 }
 
 /**
- * @brief Set queue id to which IO should be submitted
+ * @brief Set queue to which IO should be submitted
  *
  * @param[in] io OCF IO to set up
- * @param[in] queue IO queue id
+ * @param[in] queue IO queue handle
  */
-static inline void ocf_io_set_queue(struct ocf_io *io, uint32_t queue)
+static inline void ocf_io_set_queue(struct ocf_io *io, ocf_queue_t queue)
 {
 	io->io_queue = queue;
 }
diff --git a/inc/ocf_mngt.h b/inc/ocf_mngt.h
index 8b8606d..53b8477 100644
--- a/inc/ocf_mngt.h
+++ b/inc/ocf_mngt.h
@@ -240,11 +240,6 @@ struct ocf_mngt_cache_config {
 		 uint32_t queue_unblock_size;
 	} backfill;
 
-	/**
-	 * @brief Number of I/O queues to be created
-	 */
-	uint32_t io_queues;
-
 	/**
 	 * @brief Start cache and keep it locked
 	 *
@@ -360,14 +355,12 @@ int ocf_mngt_cache_detach(ocf_cache_t cache);
  *
  * @param[in] ctx OCF context
  * @param[out] cache Cache handle
- * @param[in] cfg Cache configuration
  * @param[in] device_cfg Caching device configuration
  *
  * @retval 0 Cache successfully loaded
  * @retval Non-zero Error occurred during loading cache
  */
 int ocf_mngt_cache_load(ocf_ctx_t ctx, ocf_cache_t *cache,
-		struct ocf_mngt_cache_config *cfg,
 		struct ocf_mngt_cache_device_config *device_cfg);
 
 /* Adding and removing cores */
diff --git a/inc/ocf_queue.h b/inc/ocf_queue.h
index 1ce3a8d..3d795cd 100644
--- a/inc/ocf_queue.h
+++ b/inc/ocf_queue.h
@@ -11,6 +11,72 @@
  * @brief OCF queues API
  */
 
+/**
+ * @brief I/O queue operations
+ */
+struct ocf_queue_ops {
+	/**
+	 * @brief Kick I/O queue processing
+	 *
+	 * This function should inform worker, thread or any other queue
+	 * processing mechanism, that there are new requests in queue to
+	 * be processed. Processing requests synchronously in this function
+	 * is not allowed.
+	 *
+	 * @param[in] q I/O queue to be kicked
+	 */
+	void (*kick)(ocf_queue_t q);
+
+	/**
+	 * @brief Kick I/O queue processing
+	 *
+	 * This function should inform worker, thread or any other queue
+	 * processing mechanism, that there are new requests in queue to
+	 * be processed. Function kick_sync is allowed to process requests
+	 * synchronously without delegating them to the worker.
+	 *
+	 * @param[in] q I/O queue to be kicked
+	 */
+	void (*kick_sync)(ocf_queue_t q);
+
+	/**
+	 * @brief Stop I/O queue
+	 *
+	 * @param[in] q I/O queue beeing stopped
+	 */
+	void (*stop)(ocf_queue_t q);
+};
+
+/**
+ * @brief Allocate IO queue and add it to list in cache
+ *
+ * @param[in] cache Handle to cache instance
+ * @param[out] queue Handle to created queue
+ * @param[in] ops Queue operations
+ *
+ * @return Zero on success, otherwise error code
+ */
+int ocf_queue_create(ocf_cache_t cache, ocf_queue_t *queue,
+		const struct ocf_queue_ops *ops);
+
+/**
+ * @brief Increase reference counter in queue
+ *
+ * @param[in] queue Queue
+ *
+ */
+void ocf_queue_get(ocf_queue_t queue);
+
+/**
+ * @brief Decrease reference counter in queue
+ *
+ * @note If queue don't have any reference - deallocate it
+ *
+ * @param[in] queue Queue
+ *
+ */
+void ocf_queue_put(ocf_queue_t queue);
+
 /**
  * @brief Process single request from queue
  *
@@ -60,13 +126,4 @@ uint32_t ocf_queue_pending_io(ocf_queue_t q);
  */
 ocf_cache_t ocf_queue_get_cache(ocf_queue_t q);
 
-/**
- * @brief Get I/O queue id
- *
- * @param[in] q I/O queue
- *
- * @retval I/O queue id
- */
-uint32_t ocf_queue_get_id(ocf_queue_t q);
-
 #endif
diff --git a/inc/ocf_trace.h b/inc/ocf_trace.h
index 92439cf..f46c222 100644
--- a/inc/ocf_trace.h
+++ b/inc/ocf_trace.h
@@ -74,9 +74,6 @@ struct ocf_event_cache_desc {
 	/** Number of cores */
 	uint32_t cores_no;
 
-	/** Number of IO queues */
-	uint32_t io_queues_no;
-
 	/** Trace version */
 	uint32_t version;
 };
@@ -152,7 +149,7 @@ struct ocf_event_io_cmpl {
  *
  * @param[in] cache OCF cache
  * @param[in] trace_ctx Tracing context
- * @param[in] qid Queue Id
+ * @param[in] queue Queue handle
  * @param[out] trace Event log
  * @param[out] size Size of event log
  *
@@ -160,7 +157,7 @@ struct ocf_event_io_cmpl {
  * @return Non-zero error
  */
 typedef void (*ocf_trace_callback_t)(ocf_cache_t cache, void *trace_ctx,
-		uint32_t qid, const void* trace, const uint32_t size);
+		ocf_queue_t queue, const void* trace, const uint32_t size);
 
 /**
  * @brief Start tracing
diff --git a/src/cleaning/acp.c b/src/cleaning/acp.c
index 2f3f528..64abe5e 100644
--- a/src/cleaning/acp.c
+++ b/src/cleaning/acp.c
@@ -536,7 +536,7 @@ static bool _acp_prepare_flush_data(struct acp_context *acp,
 
 /* Clean at most 'flush_max_buffers' cache lines from current or newly
  * selected chunk */
-void cleaning_policy_acp_perform_cleaning(struct ocf_cache *cache,
+void cleaning_policy_acp_perform_cleaning(ocf_cache_t cache,
 		ocf_cleaner_end_t cmpl)
 {
 	struct acp_cleaning_policy_config *config;
diff --git a/src/cleaning/alru.c b/src/cleaning/alru.c
index 6d0373e..9ffaeb1 100644
--- a/src/cleaning/alru.c
+++ b/src/cleaning/alru.c
@@ -449,7 +449,7 @@ void cleaning_policy_alru_setup(struct ocf_cache *cache)
 	config->activity_threshold = OCF_ALRU_DEFAULT_ACTIVITY_THRESHOLD;
 }
 
-int cleaning_policy_alru_initialize(struct ocf_cache *cache, int init_metadata)
+int cleaning_policy_alru_initialize(ocf_cache_t cache, int init_metadata)
 {
 	struct ocf_user_part *part;
 	ocf_part_id_t part_id;
diff --git a/src/cleaning/cleaning.c b/src/cleaning/cleaning.c
index 3997e71..dc8496e 100644
--- a/src/cleaning/cleaning.c
+++ b/src/cleaning/cleaning.c
@@ -11,6 +11,7 @@
 #include "../ocf_ctx_priv.h"
 #include "../mngt/ocf_mngt_common.h"
 #include "../metadata/metadata.h"
+#include "../ocf_queue_priv.h"
 
 #define SLEEP_TIME_MS (1000)
 
@@ -63,11 +64,6 @@ void ocf_cleaner_set_cmpl(ocf_cleaner_t cleaner, ocf_cleaner_end_t fn)
 	cleaner->end = fn;
 }
 
-void ocf_cleaner_set_io_queue(ocf_cleaner_t cleaner, uint32_t io_queue)
-{
-	cleaner->io_queue = io_queue;
-}
-
 void ocf_cleaner_set_priv(ocf_cleaner_t c, void *priv)
 {
 	OCF_CHECK_NULL(c);
@@ -112,13 +108,21 @@ static void ocf_cleaner_run_complete(ocf_cleaner_t cleaner, uint32_t interval)
 
 	env_rwsem_up_write(&cache->lock);
 	cleaner->end(cleaner, interval);
+
+	ocf_queue_put(cleaner->io_queue);
+	cleaner->io_queue = NULL;
 }
 
-void ocf_cleaner_run(ocf_cleaner_t cleaner)
+void ocf_cleaner_run(ocf_cleaner_t cleaner, ocf_queue_t queue)
 {
-	ocf_cache_t cache = ocf_cleaner_get_cache(cleaner);
+	ocf_cache_t cache;
 	ocf_cleaning_t clean_type;
 
+	OCF_CHECK_NULL(cleaner);
+	OCF_CHECK_NULL(queue);
+
+	cache = ocf_cleaner_get_cache(cleaner);
+
 	/* Do not involve cleaning when cache is not running
 	 * (error, etc.).
 	 */
@@ -143,6 +147,9 @@ void ocf_cleaner_run(ocf_cleaner_t cleaner)
 
 	ENV_BUG_ON(clean_type >= ocf_cleaning_max);
 
+	ocf_queue_get(queue);
+	cleaner->io_queue = queue;
+
 	/* Call cleaning. */
 	if (cleaning_policy_ops[clean_type].perform_cleaning) {
 		cleaning_policy_ops[clean_type].perform_cleaning(cache,
diff --git a/src/cleaning/cleaning.h b/src/cleaning/cleaning.h
index d625e26..bb9061e 100644
--- a/src/cleaning/cleaning.h
+++ b/src/cleaning/cleaning.h
@@ -59,7 +59,7 @@ extern struct cleaning_policy_ops cleaning_policy_ops[ocf_cleaning_max];
 
 struct ocf_cleaner {
 	void *cleaning_policy_context;
-	uint32_t io_queue;
+	ocf_queue_t io_queue;
 	ocf_cleaner_end_t end;
 	void *priv;
 };
diff --git a/src/engine/cache_engine.c b/src/engine/cache_engine.c
index cbfe539..8512e17 100644
--- a/src/engine/cache_engine.c
+++ b/src/engine/cache_engine.c
@@ -106,8 +106,7 @@ const struct ocf_io_if *ocf_get_io_if(ocf_req_cache_mode_t req_cache_mode)
 	return cache_mode_io_if_map[req_cache_mode];
 }
 
-struct ocf_request *ocf_engine_pop_req(struct ocf_cache *cache,
-		struct ocf_queue *q)
+struct ocf_request *ocf_engine_pop_req(ocf_cache_t cache, ocf_queue_t q)
 {
 	unsigned long lock_flags = 0;
 	struct ocf_request *req;
@@ -263,6 +262,7 @@ int ocf_engine_hndl_fast_req(struct ocf_request *req,
 		ocf_req_cache_mode_t req_cache_mode)
 {
 	const struct ocf_io_if *io_if;
+	int ret;
 
 	io_if = ocf_get_io_if(req_cache_mode);
 	if (!io_if)
@@ -270,12 +270,16 @@ int ocf_engine_hndl_fast_req(struct ocf_request *req,
 
 	switch (req->rw) {
 	case OCF_READ:
-		return io_if->read(req);
+		ret = io_if->read(req);
+		break;
 	case OCF_WRITE:
-		return io_if->write(req);
+		ret = io_if->write(req);
+		break;
 	default:
 		return OCF_FAST_PATH_NO;
 	}
+
+	return ret;
 }
 
 static void ocf_engine_hndl_2dc_req(struct ocf_request *req)
diff --git a/src/engine/engine_common.c b/src/engine/engine_common.c
index 934ac36..55e4e83 100644
--- a/src/engine/engine_common.c
+++ b/src/engine/engine_common.c
@@ -117,7 +117,7 @@ void ocf_engine_update_req_info(struct ocf_cache *cache,
 			req->info.dirty_any++;
 
 			/* Check if cache line is fully dirty */
-			if (metadata_test_dirty_sec(cache, _entry->coll_idx, 
+			if (metadata_test_dirty_sec(cache, _entry->coll_idx,
 				start_sector, end_sector))
 				req->info.dirty_all++;
 		}
@@ -488,14 +488,14 @@ void ocf_engine_update_request_stats(struct ocf_request *req)
 
 void ocf_engine_push_req_back(struct ocf_request *req, bool allow_sync)
 {
-	struct ocf_cache *cache = req->cache;
-	struct ocf_queue *q = NULL;
+	ocf_cache_t cache = req->cache;
+	ocf_queue_t q = NULL;
 	unsigned long lock_flags = 0;
 
 	INIT_LIST_HEAD(&req->list);
 
-	ENV_BUG_ON(req->io_queue >= cache->io_queues_no);
-	q = &cache->io_queues[req->io_queue];
+	ENV_BUG_ON(!req->io_queue);
+	q = req->io_queue;
 
 	env_spinlock_lock_irqsave(&q->io_list_lock, lock_flags);
 
@@ -508,19 +508,18 @@ void ocf_engine_push_req_back(struct ocf_request *req, bool allow_sync)
 		env_atomic_set(&cache->last_access_ms,
 				env_ticks_to_msecs(env_get_tick_count()));
 
-	ctx_queue_kick(cache->owner, q, allow_sync);
+	ocf_queue_kick(q, allow_sync);
 }
 
 void ocf_engine_push_req_front(struct ocf_request *req, bool allow_sync)
 {
-	struct ocf_cache *cache = req->cache;
-	struct ocf_queue *q = NULL;
+	ocf_cache_t cache = req->cache;
+	ocf_queue_t q = NULL;
 	unsigned long lock_flags = 0;
 
 	INIT_LIST_HEAD(&req->list);
 
-	ENV_BUG_ON(req->io_queue >= cache->io_queues_no);
-	q = &cache->io_queues[req->io_queue];
+	q = req->io_queue;
 
 	env_spinlock_lock_irqsave(&q->io_list_lock, lock_flags);
 
@@ -533,7 +532,7 @@ void ocf_engine_push_req_front(struct ocf_request *req, bool allow_sync)
 		env_atomic_set(&cache->last_access_ms,
 				env_ticks_to_msecs(env_get_tick_count()));
 
-	ctx_queue_kick(cache->owner, q, allow_sync);
+	ocf_queue_kick(q, allow_sync);
 }
 
 void ocf_engine_push_req_front_if(struct ocf_request *req,
diff --git a/src/eviction/eviction.c b/src/eviction/eviction.c
index 01f463a..9c59903 100644
--- a/src/eviction/eviction.c
+++ b/src/eviction/eviction.c
@@ -40,8 +40,8 @@ static uint32_t ocf_evict_calculate(struct ocf_user_part *part,
 	return to_evict;
 }
 
-static inline uint32_t ocf_evict_do(struct ocf_cache *cache,
-		uint32_t io_queue, const uint32_t evict_cline_no,
+static inline uint32_t ocf_evict_do(ocf_cache_t cache,
+		ocf_queue_t io_queue, const uint32_t evict_cline_no,
 		ocf_core_id_t core_id, ocf_part_id_t target_part_id)
 {
 	uint32_t to_evict = 0, evicted = 0;
diff --git a/src/eviction/eviction.h b/src/eviction/eviction.h
index d213063..eb4de45 100644
--- a/src/eviction/eviction.h
+++ b/src/eviction/eviction.h
@@ -32,22 +32,22 @@ union eviction_policy_meta {
  * set core_id to -2 to purge the whole cache partition
  */
 struct eviction_policy_ops {
-	void (*init_cline)(struct ocf_cache *cache,
+	void (*init_cline)(ocf_cache_t cache,
 			ocf_cache_line_t cline);
-	void (*rm_cline)(struct ocf_cache *cache,
+	void (*rm_cline)(ocf_cache_t cache,
 			ocf_cache_line_t cline);
-	bool (*can_evict)(struct ocf_cache *cache);
-	uint32_t (*req_clines)(struct ocf_cache *cache,
-			uint32_t io_queue, ocf_part_id_t part_id,
+	bool (*can_evict)(ocf_cache_t cache);
+	uint32_t (*req_clines)(ocf_cache_t cache,
+			ocf_queue_t io_queue, ocf_part_id_t part_id,
 			uint32_t cline_no, ocf_core_id_t core_id);
-	void (*hot_cline)(struct ocf_cache *cache,
+	void (*hot_cline)(ocf_cache_t cache,
 			ocf_cache_line_t cline);
-	void (*init_evp)(struct ocf_cache *cache,
+	void (*init_evp)(ocf_cache_t cache,
 			ocf_part_id_t part_id);
-	void (*dirty_cline)(struct ocf_cache *cache,
+	void (*dirty_cline)(ocf_cache_t cache,
 			ocf_part_id_t part_id,
 			uint32_t cline_no);
-	void (*clean_cline)(struct ocf_cache *cache,
+	void (*clean_cline)(ocf_cache_t cache,
 			ocf_part_id_t part_id,
 			uint32_t cline_no);
 	const char *name;
@@ -62,9 +62,9 @@ extern struct eviction_policy_ops evict_policy_ops[ocf_eviction_max];
  * or the destination partition ID for the free buffers
  * (it matches label and is part of the object (#core_id) IO group)
  */
-int space_managment_evict_do(struct ocf_cache *cache,
+int space_managment_evict_do(ocf_cache_t cache,
 		struct ocf_request *req, uint32_t evict_cline_no);
 
-int space_management_free(struct ocf_cache *cache, uint32_t count);
+int space_management_free(ocf_cache_t cache, uint32_t count);
 
 #endif
diff --git a/src/eviction/lru.c b/src/eviction/lru.c
index d7f9c2c..604e1fc 100644
--- a/src/eviction/lru.c
+++ b/src/eviction/lru.c
@@ -29,7 +29,7 @@
 #define is_lru_tail(x) (x == collision_table_entries)
 
 /* Sets the given collision_index as the new _head_ of the LRU list. */
-static inline void update_lru_head(struct ocf_cache *cache,
+static inline void update_lru_head(ocf_cache_t cache,
 		int partition_id, unsigned int collision_index,
 		int cline_dirty)
 {
@@ -43,7 +43,7 @@ static inline void update_lru_head(struct ocf_cache *cache,
 }
 
 /* Sets the given collision_index as the new _tail_ of the LRU list. */
-static inline void update_lru_tail(struct ocf_cache *cache,
+static inline void update_lru_tail(ocf_cache_t cache,
 		int partition_id, unsigned int collision_index,
 		int cline_dirty)
 {
@@ -58,7 +58,7 @@ static inline void update_lru_tail(struct ocf_cache *cache,
 /* Sets the given collision_index as the new _head_ and _tail_ of
  * the LRU list.
  */
-static inline void update_lru_head_tail(struct ocf_cache *cache,
+static inline void update_lru_head_tail(ocf_cache_t cache,
 		int partition_id, unsigned int collision_index, int cline_dirty)
 {
 	update_lru_head(cache, partition_id, collision_index, cline_dirty);
@@ -66,7 +66,7 @@ static inline void update_lru_head_tail(struct ocf_cache *cache,
 }
 
 /* Adds the given collision_index to the _head_ of the LRU list */
-static void add_lru_head(struct ocf_cache *cache, int partition_id,
+static void add_lru_head(ocf_cache_t cache, int partition_id,
 		unsigned int collision_index, int cline_dirty)
 {
 	unsigned int curr_head_index;
@@ -121,7 +121,7 @@ static void add_lru_head(struct ocf_cache *cache, int partition_id,
 }
 
 /* Deletes the node with the given collision_index from the lru list */
-static void remove_lru_list(struct ocf_cache *cache, int partition_id,
+static void remove_lru_list(ocf_cache_t cache, int partition_id,
 		unsigned int collision_index, int cline_dirty)
 {
 	int is_clean_head = 0, is_clean_tail = 0, is_dirty_head = 0, is_dirty_tail = 0;
@@ -250,7 +250,7 @@ static void remove_lru_list(struct ocf_cache *cache, int partition_id,
 
 /*-- End of LRU functions*/
 
-void evp_lru_init_cline(struct ocf_cache *cache, ocf_cache_line_t cline)
+void evp_lru_init_cline(ocf_cache_t cache, ocf_cache_line_t cline)
 {
 	union eviction_policy_meta eviction;
 
@@ -264,7 +264,7 @@ void evp_lru_init_cline(struct ocf_cache *cache, ocf_cache_line_t cline)
 
 
 /* the caller must hold the metadata lock */
-void evp_lru_rm_cline(struct ocf_cache *cache, ocf_cache_line_t cline)
+void evp_lru_rm_cline(ocf_cache_t cache, ocf_cache_line_t cline)
 {
 	ocf_part_id_t part_id = ocf_metadata_get_partition_id(cache, cline);
 
@@ -278,7 +278,7 @@ static void evp_lru_clean_end(void *private_data, int error)
 	env_atomic_set(cleaning_in_progress, 0);
 }
 
-static int evp_lru_clean_getter(struct ocf_cache *cache,
+static int evp_lru_clean_getter(ocf_cache_t cache,
 		void *getter_context, uint32_t item, ocf_cache_line_t *line)
 {
 	union eviction_policy_meta eviction;
@@ -306,7 +306,7 @@ static int evp_lru_clean_getter(struct ocf_cache *cache,
 	return -1;
 }
 
-static void evp_lru_clean(struct ocf_cache *cache, uint32_t io_queue,
+static void evp_lru_clean(ocf_cache_t cache, ocf_queue_t io_queue,
 		ocf_part_id_t part_id, uint32_t count)
 {
 	env_atomic *progress = &cache->cleaning[part_id];
@@ -342,7 +342,7 @@ static void evp_lru_zero_line_complete(struct ocf_request *ocf_req, int error)
 	env_atomic_dec(&ocf_req->cache->pending_eviction_clines);
 }
 
-static void evp_lru_zero_line(struct ocf_cache *cache, uint32_t io_queue,
+static void evp_lru_zero_line(ocf_cache_t cache, ocf_queue_t io_queue,
 		ocf_cache_line_t line)
 {
 	struct ocf_request *req;
@@ -352,11 +352,11 @@ static void evp_lru_zero_line(struct ocf_cache *cache, uint32_t io_queue,
 	ocf_metadata_get_core_info(cache, line, &id, &core_line);
 	addr = core_line * ocf_line_size(cache);
 
-	req = ocf_req_new(cache, id, addr, ocf_line_size(cache), OCF_WRITE);
+	req = ocf_req_new(io_queue, &cache->core[id], addr,
+			ocf_line_size(cache), OCF_WRITE);
 	if (req) {
 		req->info.internal = true;
 		req->complete = evp_lru_zero_line_complete;
-		req->io_queue = io_queue;
 
 		env_atomic_inc(&cache->pending_eviction_clines);
 
@@ -364,7 +364,7 @@ static void evp_lru_zero_line(struct ocf_cache *cache, uint32_t io_queue,
 	}
 }
 
-bool evp_lru_can_evict(struct ocf_cache *cache)
+bool evp_lru_can_evict(ocf_cache_t cache)
 {
 	if (env_atomic_read(&cache->pending_eviction_clines) >=
 			OCF_PENDING_EVICTION_LIMIT) {
@@ -375,7 +375,7 @@ bool evp_lru_can_evict(struct ocf_cache *cache)
 }
 
 /* the caller must hold the metadata lock */
-uint32_t evp_lru_req_clines(struct ocf_cache *cache, uint32_t io_queue,
+uint32_t evp_lru_req_clines(ocf_cache_t cache, ocf_queue_t io_queue,
 		ocf_part_id_t part_id, uint32_t cline_no, ocf_core_id_t core_id)
 {
 	uint32_t i;
@@ -438,7 +438,7 @@ uint32_t evp_lru_req_clines(struct ocf_cache *cache, uint32_t io_queue,
 }
 
 /* the caller must hold the metadata lock */
-void evp_lru_hot_cline(struct ocf_cache *cache, ocf_cache_line_t cline)
+void evp_lru_hot_cline(ocf_cache_t cache, ocf_cache_line_t cline)
 {
 	ocf_part_id_t part_id = ocf_metadata_get_partition_id(cache, cline);
 	struct ocf_user_part *part = &cache->user_parts[part_id];
@@ -469,7 +469,7 @@ void evp_lru_hot_cline(struct ocf_cache *cache, ocf_cache_line_t cline)
 	add_lru_head(cache, part_id, cline, cline_dirty);
 }
 
-void evp_lru_init_evp(struct ocf_cache *cache, ocf_part_id_t part_id)
+void evp_lru_init_evp(ocf_cache_t cache, ocf_part_id_t part_id)
 {
 	unsigned int collision_table_entries =
 			cache->device->collision_table_entries;
@@ -483,7 +483,7 @@ void evp_lru_init_evp(struct ocf_cache *cache, ocf_part_id_t part_id)
 	part->runtime->eviction.policy.lru.dirty_tail = collision_table_entries;
 }
 
-void evp_lru_clean_cline(struct ocf_cache *cache, ocf_part_id_t part_id,
+void evp_lru_clean_cline(ocf_cache_t cache, ocf_part_id_t part_id,
 		uint32_t cline)
 {
 	OCF_METADATA_EVICTION_LOCK();
@@ -492,7 +492,7 @@ void evp_lru_clean_cline(struct ocf_cache *cache, ocf_part_id_t part_id,
 	OCF_METADATA_EVICTION_UNLOCK();
 }
 
-void evp_lru_dirty_cline(struct ocf_cache *cache, ocf_part_id_t part_id,
+void evp_lru_dirty_cline(ocf_cache_t cache, ocf_part_id_t part_id,
 		uint32_t cline)
 {
 	OCF_METADATA_EVICTION_LOCK();
diff --git a/src/eviction/lru.h b/src/eviction/lru.h
index 7e2df4e..602f63a 100644
--- a/src/eviction/lru.h
+++ b/src/eviction/lru.h
@@ -12,7 +12,7 @@ void evp_lru_init_cline(struct ocf_cache *cache,
 		ocf_cache_line_t cline);
 void evp_lru_rm_cline(struct ocf_cache *cache, ocf_cache_line_t cline);
 bool evp_lru_can_evict(struct ocf_cache *cache);
-uint32_t evp_lru_req_clines(struct ocf_cache *cache, uint32_t io_queue,
+uint32_t evp_lru_req_clines(struct ocf_cache *cache, ocf_queue_t io_queue,
 		ocf_part_id_t part_id, uint32_t cline_no,
 		ocf_core_id_t core_id);
 void evp_lru_hot_cline(struct ocf_cache *cache, ocf_cache_line_t cline);
diff --git a/src/eviction/ops.h b/src/eviction/ops.h
index 53cab6b..2d57c14 100644
--- a/src/eviction/ops.h
+++ b/src/eviction/ops.h
@@ -53,7 +53,7 @@ static inline bool ocf_eviction_can_evict(struct ocf_cache *cache)
 }
 
 static inline uint32_t ocf_eviction_need_space(struct ocf_cache *cache,
-		uint32_t io_queue, ocf_part_id_t part_id, uint32_t clines,
+		ocf_queue_t io_queue, ocf_part_id_t part_id, uint32_t clines,
 		ocf_core_id_t core_id)
 {
 	uint8_t type;
diff --git a/src/metadata/metadata_io.c b/src/metadata/metadata_io.c
index 72b074c..020694e 100644
--- a/src/metadata/metadata_io.c
+++ b/src/metadata/metadata_io.c
@@ -44,7 +44,7 @@ static struct ocf_io_if meta_restart_if = {
 /*
  * Get max pages for IO
  */
-static uint32_t metadata_io_max_page(struct ocf_cache *cache)
+static uint32_t metadata_io_max_page(ocf_cache_t cache)
 {
 	return ocf_volume_get_max_io_size(&cache->device->volume) / PAGE_SIZE;
 }
@@ -65,7 +65,7 @@ static void metadata_io_read_i_atomic_end(struct ocf_io *io, int error)
 /*
  * Iterative read request
  */
-int metadata_io_read_i_atomic(struct ocf_cache *cache,
+int metadata_io_read_i_atomic(ocf_cache_t cache,
 		ocf_metadata_atomic_io_event_t hndl)
 {
 	uint64_t i;
@@ -159,7 +159,7 @@ static int ocf_restart_meta_io(struct ocf_request *req)
 {
 	struct ocf_io *io;
 	struct metadata_io_request *meta_io_req;
-	struct ocf_cache *cache;
+	ocf_cache_t cache;
 	int i;
 	int ret;
 
@@ -205,7 +205,7 @@ static void metadata_io_write_i_asynch_end(struct metadata_io_request *request,
 		int error)
 {
 	struct metadata_io_request_asynch *a_req;
-	struct ocf_cache *cache;
+	ocf_cache_t cache;
 
 	OCF_CHECK_NULL(request);
 
@@ -247,7 +247,7 @@ static void metadata_io_write_i_asynch_end(struct metadata_io_request *request,
 	ocf_metadata_updater_kick(cache);
 }
 
-static void metadata_io_req_error(struct ocf_cache *cache,
+static void metadata_io_req_error(ocf_cache_t cache,
 				  struct metadata_io_request_asynch *a_req,
 				  uint32_t i, int error)
 {
@@ -262,7 +262,7 @@ static void metadata_io_req_error(struct ocf_cache *cache,
 /*
  * Iterative write request asynchronously
  */
-int metadata_io_write_i_asynch(struct ocf_cache *cache, uint32_t queue,
+int metadata_io_write_i_asynch(ocf_cache_t cache, ocf_queue_t queue,
 		void *context, uint32_t page, uint32_t count,
 		ocf_metadata_io_event_t fill_hndl,
 		ocf_metadata_io_hndl_on_write_t compl_hndl)
@@ -439,7 +439,7 @@ static void metadata_io_end(struct ocf_io *io, int error)
 	ctx_data_t *data = ocf_io_get_data(io);
 	uint32_t page = BYTES_TO_PAGES(io->addr);
 	uint32_t count = BYTES_TO_PAGES(io->bytes);
-	struct ocf_cache *cache = mio->cache;
+	ocf_cache_t cache = mio->cache;
 	uint32_t i = 0;
 
 	if (error) {
@@ -463,7 +463,7 @@ out:
 }
 
 static int metadata_submit_io(
-		struct ocf_cache *cache,
+		ocf_cache_t cache,
 		struct metadata_io *mio,
 		uint32_t count,
 		uint32_t written)
@@ -532,7 +532,7 @@ static int metadata_io(struct metadata_io *mio)
 	unsigned char step = 0;
 	int err;
 
-	struct ocf_cache *cache = mio->cache;
+	ocf_cache_t cache = mio->cache;
 
 	/* Check direction value correctness */
 	switch (mio->dir) {
@@ -572,7 +572,7 @@ static int metadata_io(struct metadata_io *mio)
 /*
  *
  */
-int metadata_io_write_i(struct ocf_cache *cache,
+int metadata_io_write_i(ocf_cache_t cache,
 		uint32_t page, uint32_t count,
 		ocf_metadata_io_event_t hndl_fn, void *hndl_cntx)
 {
@@ -591,7 +591,7 @@ int metadata_io_write_i(struct ocf_cache *cache,
 /*
  *
  */
-int metadata_io_read_i(struct ocf_cache *cache,
+int metadata_io_read_i(ocf_cache_t cache,
 		uint32_t page, uint32_t count,
 		ocf_metadata_io_event_t hndl_fn, void *hndl_cntx)
 {
@@ -610,7 +610,7 @@ int metadata_io_read_i(struct ocf_cache *cache,
 /*
  *
  */
-static int metadata_io_write_fill(struct ocf_cache *cache,
+static int metadata_io_write_fill(ocf_cache_t cache,
 		ctx_data_t *data, uint32_t page, void *context)
 {
 	ctx_data_wr_check(cache->owner, data, context, PAGE_SIZE);
@@ -620,7 +620,7 @@ static int metadata_io_write_fill(struct ocf_cache *cache,
 /*
  * Write request
  */
-int metadata_io_write(struct ocf_cache *cache,
+int metadata_io_write(ocf_cache_t cache,
 		void *data, uint32_t page)
 {
 	struct metadata_io mio = {
diff --git a/src/metadata/metadata_io.h b/src/metadata/metadata_io.h
index ee74227..fb2d355 100644
--- a/src/metadata/metadata_io.h
+++ b/src/metadata/metadata_io.h
@@ -25,7 +25,7 @@
  * @retval 0 Success
  * @retval Non-zero Error which will bee finally returned to the caller
  */
-typedef int (*ocf_metadata_io_event_t)(struct ocf_cache *cache,
+typedef int (*ocf_metadata_io_event_t)(ocf_cache_t cache,
 		ctx_data_t *data, uint32_t page, void *context);
 
 /**
@@ -36,7 +36,7 @@ typedef int (*ocf_metadata_io_event_t)(struct ocf_cache *cache,
  * @param error - error
  * @param page - page that was written
  */
-typedef void (*ocf_metadata_io_hndl_on_write_t)(struct ocf_cache *cache,
+typedef void (*ocf_metadata_io_hndl_on_write_t)(ocf_cache_t cache,
 		void *context, int error);
 
 struct metadata_io_request_asynch;
@@ -45,7 +45,7 @@ struct metadata_io_request_asynch;
  * IO request context
  */
 struct metadata_io_request {
-	struct ocf_cache *cache;
+	ocf_cache_t cache;
 	void *context;
 	uint32_t page;
 	uint32_t count;
@@ -75,7 +75,7 @@ struct metadata_io_request_atomic {
 struct metadata_io {
 	int error;
 	int dir;
-	struct ocf_cache *cache;
+	ocf_cache_t cache;
 	uint32_t page;
 	uint32_t count;
 	env_completion completion;
@@ -88,7 +88,7 @@ struct metadata_io {
  * Asynchronous IO request context
  */
 struct metadata_io_request_asynch {
-	struct ocf_cache *cache;
+	ocf_cache_t cache;
 	struct metadata_io_request *reqs;
 	void *context;
 	int error;
@@ -111,7 +111,7 @@ struct metadata_io_request_asynch {
  * @retval Non-zero Error which will bee finally returned to the caller
  */
 typedef int (*ocf_metadata_atomic_io_event_t)(
-		struct ocf_cache *cache, uint64_t sector_addr,
+		ocf_cache_t cache, uint64_t sector_addr,
 		uint32_t sector_no, ctx_data_t *data);
 
 /**
@@ -122,10 +122,10 @@ typedef int (*ocf_metadata_atomic_io_event_t)(
  * @param page - Page of SSD (cache device) where data has to be placed
  * @return 0 - No errors, otherwise error occurred
  */
-int metadata_io_write(struct ocf_cache *cache,
+int metadata_io_write(ocf_cache_t cache,
 		void *data, uint32_t page);
 
-int metadata_io_read_i_atomic(struct ocf_cache *cache,
+int metadata_io_read_i_atomic(ocf_cache_t cache,
 		ocf_metadata_atomic_io_event_t hndl);
 
 /**
@@ -139,7 +139,7 @@ int metadata_io_read_i_atomic(struct ocf_cache *cache,
  *
  * @return 0 - No errors, otherwise error occurred
  */
-int metadata_io_write_i(struct ocf_cache *cache,
+int metadata_io_write_i(ocf_cache_t cache,
 		uint32_t page, uint32_t count,
 		ocf_metadata_io_event_t hndl_fn, void *hndl_cntx);
 
@@ -154,7 +154,7 @@ int metadata_io_write_i(struct ocf_cache *cache,
  *
  * @return 0 - No errors, otherwise error occurred
  */
-int metadata_io_read_i(struct ocf_cache *cache,
+int metadata_io_read_i(ocf_cache_t cache,
 		uint32_t page, uint32_t count,
 		ocf_metadata_io_event_t hndl_fn, void *hndl_cntx);
 
@@ -170,7 +170,7 @@ int metadata_io_read_i(struct ocf_cache *cache,
  *
  * @return 0 - No errors, otherwise error occurred
  */
-int metadata_io_write_i_asynch(struct ocf_cache *cache, uint32_t queue,
+int metadata_io_write_i_asynch(ocf_cache_t cache, ocf_queue_t queue,
 		void *context, uint32_t page, uint32_t count,
 		ocf_metadata_io_event_t fill_hndl,
 		ocf_metadata_io_hndl_on_write_t compl_hndl);
diff --git a/src/metadata/metadata_raw.c b/src/metadata/metadata_raw.c
index 6473bf7..db172ba 100644
--- a/src/metadata/metadata_raw.c
+++ b/src/metadata/metadata_raw.c
@@ -72,7 +72,7 @@ static bool _raw_ssd_page_is_valid(struct ocf_metadata_raw *raw, uint32_t page)
 /*
  * RAM Implementation - De-Initialize
  */
-static int _raw_ram_deinit(struct ocf_cache *cache,
+static int _raw_ram_deinit(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw)
 {
 	OCF_DEBUG_TRACE(cache);
@@ -88,7 +88,7 @@ static int _raw_ram_deinit(struct ocf_cache *cache,
 /*
  * RAM Implementation - Initialize
  */
-static int _raw_ram_init(struct ocf_cache *cache,
+static int _raw_ram_init(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw)
 {
 	size_t mem_pool_size;
@@ -109,7 +109,7 @@ static int _raw_ram_init(struct ocf_cache *cache,
 /*
  * RAM Implementation - Size of
  */
-static size_t _raw_ram_size_of(struct ocf_cache *cache,
+static size_t _raw_ram_size_of(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw)
 {
 	size_t size;
@@ -123,7 +123,7 @@ static size_t _raw_ram_size_of(struct ocf_cache *cache,
 /*
  * RAM Implementation - Size on SSD
  */
-static uint32_t _raw_ram_size_on_ssd(struct ocf_cache *cache,
+static uint32_t _raw_ram_size_on_ssd(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw)
 {
 	const size_t alignment = 128 * KiB / PAGE_SIZE;
@@ -134,7 +134,7 @@ static uint32_t _raw_ram_size_on_ssd(struct ocf_cache *cache,
 /*
  * RAM Implementation - Checksum
  */
-static uint32_t _raw_ram_checksum(struct ocf_cache *cache,
+static uint32_t _raw_ram_checksum(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw)
 {
 	uint64_t i;
@@ -152,7 +152,7 @@ static uint32_t _raw_ram_checksum(struct ocf_cache *cache,
 /*
  * RAM Implementation - Get entry
  */
-static int _raw_ram_get(struct ocf_cache *cache,
+static int _raw_ram_get(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw, ocf_cache_line_t line,
 		void *data, uint32_t size)
 {
@@ -164,7 +164,7 @@ static int _raw_ram_get(struct ocf_cache *cache,
 /*
  * RAM Implementation - Read only entry access
  */
-static const void *_raw_ram_rd_access(struct ocf_cache *cache,
+static const void *_raw_ram_rd_access(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw, ocf_cache_line_t line,
 		uint32_t size)
 {
@@ -176,7 +176,7 @@ static const void *_raw_ram_rd_access(struct ocf_cache *cache,
 /*
  * RAM Implementation - Read only entry access
  */
-static void *_raw_ram_wr_access(struct ocf_cache *cache,
+static void *_raw_ram_wr_access(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw, ocf_cache_line_t line,
 		uint32_t size)
 {
@@ -188,7 +188,7 @@ static void *_raw_ram_wr_access(struct ocf_cache *cache,
 /*
  * RAM Implementation - Set Entry
  */
-static int _raw_ram_set(struct ocf_cache *cache,
+static int _raw_ram_set(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw, ocf_cache_line_t line,
 		void *data, uint32_t size)
 {
@@ -200,7 +200,7 @@ static int _raw_ram_set(struct ocf_cache *cache,
 /*
  * RAM Implementation - Flush specified element from SSD
  */
-static int _raw_ram_flush(struct ocf_cache *cache,
+static int _raw_ram_flush(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw, ocf_cache_line_t line)
 {
 	OCF_DEBUG_PARAM(cache, "Line = %u", line);
@@ -215,7 +215,7 @@ static int _raw_ram_flush(struct ocf_cache *cache,
 /*
  * RAM Implementation - Load all IO callback
  */
-static int _raw_ram_load_all_io(struct ocf_cache *cache,
+static int _raw_ram_load_all_io(ocf_cache_t cache,
 		ctx_data_t *data, uint32_t page, void *context)
 {
 	ocf_cache_line_t line;
@@ -241,7 +241,7 @@ static int _raw_ram_load_all_io(struct ocf_cache *cache,
 /*
  * RAM Implementation - Load all metadata elements from SSD
  */
-static int _raw_ram_load_all(struct ocf_cache *cache,
+static int _raw_ram_load_all(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw)
 {
 	OCF_DEBUG_TRACE(cache);
@@ -253,7 +253,7 @@ static int _raw_ram_load_all(struct ocf_cache *cache,
 /*
  * RAM Implementation - Flush IO callback - Fill page
  */
-static int _raw_ram_flush_all_fill(struct ocf_cache *cache,
+static int _raw_ram_flush_all_fill(ocf_cache_t cache,
 		ctx_data_t *data, uint32_t page, void *context)
 {
 	ocf_cache_line_t line;
@@ -278,7 +278,7 @@ static int _raw_ram_flush_all_fill(struct ocf_cache *cache,
 /*
  * RAM Implementation - Flush all elements
  */
-static int _raw_ram_flush_all(struct ocf_cache *cache,
+static int _raw_ram_flush_all(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw)
 {
 	OCF_DEBUG_TRACE(cache);
@@ -290,7 +290,7 @@ static int _raw_ram_flush_all(struct ocf_cache *cache,
 /*
  * RAM RAM Implementation - Mark to Flush
  */
-static void _raw_ram_flush_mark(struct ocf_cache *cache,
+static void _raw_ram_flush_mark(ocf_cache_t cache,
 		struct ocf_request *req, uint32_t map_idx, int to_state,
 		uint8_t start, uint8_t stop)
 {
@@ -311,7 +311,7 @@ struct _raw_ram_flush_ctx {
 	int error;
 };
 
-static void _raw_ram_flush_do_asynch_io_complete(struct ocf_cache *cache,
+static void _raw_ram_flush_do_asynch_io_complete(ocf_cache_t cache,
 		void *context, int error)
 {
 	struct _raw_ram_flush_ctx *ctx = context;
@@ -336,7 +336,7 @@ static void _raw_ram_flush_do_asynch_io_complete(struct ocf_cache *cache,
 /*
  * RAM Implementation - Flush IO callback - Fill page
  */
-static int _raw_ram_flush_do_asynch_fill(struct ocf_cache *cache,
+static int _raw_ram_flush_do_asynch_fill(ocf_cache_t cache,
 		ctx_data_t *data, uint32_t page, void *context)
 {
 	ocf_cache_line_t line;
@@ -400,7 +400,7 @@ static void __raw_ram_flush_do_asynch_add_pages(struct ocf_request *req,
 	*pages_to_flush = j;
 }
 
-static int _raw_ram_flush_do_asynch(struct ocf_cache *cache,
+static int _raw_ram_flush_do_asynch(ocf_cache_t cache,
 		struct ocf_request *req, struct ocf_metadata_raw *raw,
 		ocf_req_end_t complete)
 {
@@ -575,7 +575,7 @@ static const struct raw_iface IRAW[metadata_raw_type_max] = {
  * RAW Top interface implementation
  ******************************************************************************/
 
-int ocf_metadata_raw_init(struct ocf_cache *cache,
+int ocf_metadata_raw_init(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw)
 {
 	ENV_BUG_ON(raw->raw_type < metadata_raw_type_min);
@@ -585,7 +585,7 @@ int ocf_metadata_raw_init(struct ocf_cache *cache,
 	return raw->iface->init(cache, raw);
 }
 
-int ocf_metadata_raw_deinit(struct ocf_cache *cache,
+int ocf_metadata_raw_deinit(ocf_cache_t cache,
 		struct ocf_metadata_raw *raw)
 {
 	int result;
@@ -599,7 +599,7 @@ int ocf_metadata_raw_deinit(struct ocf_cache *cache,
 	return result;
 }
 
-size_t ocf_metadata_raw_size_on_ssd(struct ocf_cache* cache,
+size_t ocf_metadata_raw_size_on_ssd(ocf_cache_t cache,
                 struct ocf_metadata_raw* raw)
 {
 	ENV_BUG_ON(raw->raw_type < metadata_raw_type_min);
diff --git a/src/mngt/ocf_mngt_cache.c b/src/mngt/ocf_mngt_cache.c
index f230be3..e70391d 100644
--- a/src/mngt/ocf_mngt_cache.c
+++ b/src/mngt/ocf_mngt_cache.c
@@ -77,13 +77,8 @@ struct ocf_cachemng_init_params {
 		bool metadata_inited : 1;
 			/*!< Metadata is inited to valid state */
 
-		bool queues_inited : 1;
-
 		bool cache_locked : 1;
 			/*!< Cache has been locked */
-
-		bool io_queues_started : 1;
-			/*!< queues are started */
 	} flags;
 
 	struct ocf_metadata_init_params {
@@ -743,7 +738,6 @@ static int _ocf_mngt_init_prepare_cache(struct ocf_cachemng_init_params *param,
 	env_rwsem_down_write(&cache->lock); /* Lock cache during setup */
 	param->flags.cache_locked = true;
 
-	cache->io_queues_no = cfg->io_queues;
 	cache->pt_unaligned_io = cfg->pt_unaligned_io;
 	cache->use_submit_io_fast = cfg->use_submit_io_fast;
 
@@ -1018,8 +1012,8 @@ static int check_ram_availability(ocf_ctx_t ctx,
  */
 static int _ocf_mngt_init_post_action(struct ocf_cachemng_attach_params *attach_params)
 {
-	int result = 0;
 	struct ocf_cache *cache = attach_params->cache;
+	int result;
 
 	/* clear clean shutdown status */
 	if (ocf_metadata_set_shutdown_status(cache,
@@ -1059,17 +1053,16 @@ static int _ocf_mngt_init_post_action(struct ocf_cachemng_attach_params *attach_
 static void _ocf_mngt_init_handle_error(ocf_cache_t cache,
 		ocf_ctx_t ctx, struct ocf_cachemng_init_params *params)
 {
-	if (!params || params->flags.io_queues_started)
-		ocf_stop_queues(cache);
-
-	if (!params || params->flags.queues_inited)
-		ocf_free_queues(cache);
+	ocf_queue_t queue, tmp_queue;
 
 	if (!params || params->flags.metadata_inited)
 		ocf_metadata_deinit(cache);
 
 	env_mutex_lock(&ctx->lock);
 
+	list_for_each_entry_safe(queue, tmp_queue, &cache->io_queues, list)
+		ocf_queue_put(queue);
+
 	if (!params || params->flags.cache_alloc) {
 		list_del(&cache->list);
 		env_vfree(cache);
@@ -1150,7 +1143,6 @@ static int _ocf_mngt_cache_init(ocf_cache_t cache,
 		struct ocf_cachemng_init_params *params)
 {
 	int i;
-	int result;
 
 	/*
 	 * Super block elements initialization
@@ -1163,10 +1155,7 @@ static int _ocf_mngt_cache_init(ocf_cache_t cache,
 				&cache->conf_meta->user_parts[i];
 	}
 
-	result = ocf_alloc_queues(cache);
-	if (result)
-		return result;
-	params->flags.queues_inited = 1;
+	INIT_LIST_HEAD(&cache->io_queues);
 
 	/* Init Partitions */
 	ocf_part_init(cache);
@@ -1219,16 +1208,6 @@ static int _ocf_mngt_cache_start(ocf_ctx_t ctx, ocf_cache_t *cache,
 	ocf_log(ctx, log_debug, "Metadata initialized\n");
 	params.flags.metadata_inited = true;
 
-	if (!params.flags.io_queues_started) {
-		result = ocf_start_queues(*cache);
-		if (result) {
-			ocf_log(ctx, log_err,
-					"Error while creating I/O queues\n");
-			return result;
-		}
-		params.flags.io_queues_started = true;
-	}
-
 	if (params.locked) {
 		/* Increment reference counter to match cache_lock /
 		   cache_unlock convention. User is expected to call
@@ -1405,9 +1384,6 @@ static int _ocf_mngt_cache_validate_cfg(struct ocf_mngt_cache_config *cfg)
 	if (!ocf_cache_line_size_is_valid(cfg->cache_line_size))
 		return -OCF_ERR_INVALID_CACHE_LINE_SIZE;
 
-	if (!cfg->io_queues)
-		return -OCF_ERR_INVAL;
-
 	if (cfg->metadata_layout >= ocf_metadata_layout_max ||
 			cfg->metadata_layout < 0) {
 		return -OCF_ERR_INVAL;
@@ -1573,6 +1549,7 @@ static int _ocf_mngt_cache_stop(ocf_cache_t cache)
 {
 	int i, j, no, result = 0;
 	ocf_ctx_t owner = cache->owner;
+	ocf_queue_t queue, tmp_queue;
 
 	no = cache->conf_meta->core_count;
 
@@ -1596,7 +1573,8 @@ static int _ocf_mngt_cache_stop(ocf_cache_t cache)
 	if (env_atomic_read(&cache->attached))
 		result = _ocf_mngt_cache_unplug(cache, true);
 
-	ocf_stop_queues(cache);
+	list_for_each_entry_safe(queue, tmp_queue, &cache->io_queues, list)
+		ocf_queue_put(queue);
 
 	env_mutex_lock(&owner->lock);
 	/* Mark device uninitialized */
diff --git a/src/mngt/ocf_mngt_common.c b/src/mngt/ocf_mngt_common.c
index 65c786a..9f2fd4f 100644
--- a/src/mngt/ocf_mngt_common.c
+++ b/src/mngt/ocf_mngt_common.c
@@ -169,7 +169,6 @@ void ocf_mngt_cache_put(ocf_cache_t cache)
 	OCF_CHECK_NULL(cache);
 
 	if (env_atomic_dec_return(&cache->ref_count) == 0) {
-		ocf_free_queues(cache);
 		ocf_metadata_deinit(cache);
 		env_vfree(cache);
 	}
diff --git a/src/ocf_cache_priv.h b/src/ocf_cache_priv.h
index 819025c..150ab0d 100644
--- a/src/ocf_cache_priv.h
+++ b/src/ocf_cache_priv.h
@@ -185,8 +185,7 @@ struct ocf_cache {
 
 	env_atomic pending_eviction_clines;
 
-	struct ocf_queue *io_queues;
-	uint32_t io_queues_no;
+	struct list_head io_queues;
 
 	uint16_t ocf_core_inactive_count;
 	struct ocf_core core[OCF_CORE_MAX];
diff --git a/src/ocf_core.c b/src/ocf_core.c
index 5976e60..146cae7 100644
--- a/src/ocf_core.c
+++ b/src/ocf_core.c
@@ -273,9 +273,6 @@ static inline void dec_counter_if_req_was_dirty(struct ocf_core_io *core_io,
 
 static inline int ocf_core_validate_io(struct ocf_io *io)
 {
-	ocf_core_t core = ocf_volume_to_core(io->volume);
-	ocf_cache_t cache = ocf_core_get_cache(core);
-
 	if (!io->volume)
 		return -EINVAL;
 
@@ -294,7 +291,7 @@ static inline int ocf_core_validate_io(struct ocf_io *io)
 	if (io->dir != OCF_READ && io->dir != OCF_WRITE)
 		return -EINVAL;
 
-	if (io->io_queue >= cache->io_queues_no)
+	if (!io->io_queue)
 		return -EINVAL;
 
 	if (!io->end)
@@ -364,8 +361,8 @@ void ocf_core_submit_io_mode(struct ocf_io *io, ocf_cache_mode_t cache_mode)
 			dec_counter_if_req_was_dirty(core_io, cache);
 	}
 
-	core_io->req = ocf_req_new(cache, ocf_core_get_id(core),
-			io->addr, io->bytes, io->dir);
+	core_io->req = ocf_req_new(io->io_queue, core, io->addr, io->bytes,
+			io->dir);
 	if (!core_io->req) {
 		dec_counter_if_req_was_dirty(core_io, cache);
 		io->end(io, -ENOMEM);
@@ -375,7 +372,6 @@ void ocf_core_submit_io_mode(struct ocf_io *io, ocf_cache_mode_t cache_mode)
 	if (core_io->req->d2c)
 		req_cache_mode = ocf_req_cache_mode_d2c;
 
-	core_io->req->io_queue = io->io_queue;
 	core_io->req->part_id = ocf_part_class2id(cache, io->io_class);
 	core_io->req->data = core_io->data;
 	core_io->req->complete = ocf_req_complete;
@@ -453,7 +449,7 @@ int ocf_core_submit_io_fast(struct ocf_io *io)
 		req_cache_mode = ocf_req_cache_mode_fast;
 	}
 
-	core_io->req = ocf_req_new_extended(cache, ocf_core_get_id(core),
+	core_io->req = ocf_req_new_extended(io->io_queue, core,
 			io->addr, io->bytes, io->dir);
 	// We need additional pointer to req in case completion arrives before
 	// we leave this function and core_io is freed
@@ -470,7 +466,6 @@ int ocf_core_submit_io_fast(struct ocf_io *io)
 		return -EIO;
 	}
 
-	req->io_queue = io->io_queue;
 	req->part_id = ocf_part_class2id(cache, io->io_class);
 	req->data = core_io->data;
 	req->complete = ocf_req_complete;
@@ -489,8 +484,7 @@ int ocf_core_submit_io_fast(struct ocf_io *io)
 
 	fast = ocf_engine_hndl_fast_req(req, req_cache_mode);
 	if (fast != OCF_FAST_PATH_NO) {
-		ocf_trace_push(cache, core_io->req->io_queue,
-				&trace_event, sizeof(trace_event));
+		ocf_trace_push(io->io_queue, &trace_event, sizeof(trace_event));
 		ocf_seq_cutoff_update(core, req);
 		return 0;
 	}
@@ -533,14 +527,13 @@ static void ocf_core_volume_submit_flush(struct ocf_io *io)
 		return;
 	}
 
-	core_io->req = ocf_req_new(cache, ocf_core_get_id(core),
-			io->addr, io->bytes, io->dir);
+	core_io->req = ocf_req_new(io->io_queue, core, io->addr, io->bytes,
+			io->dir);
 	if (!core_io->req) {
 		ocf_io_end(io, -ENOMEM);
 		return;
 	}
 
-	core_io->req->io_queue = io->io_queue;
 	core_io->req->complete = ocf_req_complete;
 	core_io->req->io = io;
 	core_io->req->data = core_io->data;
@@ -576,14 +569,13 @@ static void ocf_core_volume_submit_discard(struct ocf_io *io)
 		return;
 	}
 
-	core_io->req = ocf_req_new_discard(cache, ocf_core_get_id(core),
+	core_io->req = ocf_req_new_discard(io->io_queue, core,
 			io->addr, io->bytes, OCF_WRITE);
 	if (!core_io->req) {
 		ocf_io_end(io, -ENOMEM);
 		return;
 	}
 
-	core_io->req->io_queue = io->io_queue;
 	core_io->req->complete = ocf_req_complete;
 	core_io->req->io = io;
 	core_io->req->data = core_io->data;
@@ -653,7 +645,7 @@ static ctx_data_t *ocf_core_io_get_data(struct ocf_io *io)
 	return core_io->data;
 }
 
-const struct ocf_volume_properties ocf_core_volume_properties = { 
+const struct ocf_volume_properties ocf_core_volume_properties = {
 	.name = "OCF Core",
 	.io_priv_size = sizeof(struct ocf_core_io),
 	.volume_priv_size = sizeof(struct ocf_core_volume),
diff --git a/src/ocf_ctx_priv.h b/src/ocf_ctx_priv.h
index bd242aa..dca2461 100644
--- a/src/ocf_ctx_priv.h
+++ b/src/ocf_ctx_priv.h
@@ -136,25 +136,6 @@ static inline void ctx_data_secure_erase(ocf_ctx_t ctx, ctx_data_t *dst)
 	return ctx->ops->data.secure_erase(dst);
 }
 
-static inline int ctx_queue_init(ocf_ctx_t ctx, ocf_queue_t queue)
-{
-	return ctx->ops->queue.init(queue);
-}
-
-static inline void ctx_queue_kick(ocf_ctx_t ctx, ocf_queue_t queue,
-		bool allow_sync)
-{
-	if (allow_sync && ctx->ops->queue.kick_sync)
-		ctx->ops->queue.kick_sync(queue);
-	else
-		ctx->ops->queue.kick(queue);
-}
-
-static inline void ctx_queue_stop(ocf_ctx_t ctx, ocf_queue_t queue)
-{
-	ctx->ops->queue.stop(queue);
-}
-
 static inline int ctx_cleaner_init(ocf_ctx_t ctx, ocf_cleaner_t cleaner)
 {
 	return ctx->ops->cleaner.init(cleaner);
diff --git a/src/ocf_queue.c b/src/ocf_queue.c
index 72c614b..3e1e5ff 100644
--- a/src/ocf_queue.c
+++ b/src/ocf_queue.c
@@ -13,67 +13,52 @@
 #include "engine/cache_engine.h"
 #include "ocf_def_priv.h"
 
-int ocf_alloc_queues(struct ocf_cache *cache)
-{
-	ENV_BUG_ON(!cache->io_queues_no);
-
-	cache->io_queues = env_zalloc(
-		sizeof(*cache->io_queues) * cache->io_queues_no, ENV_MEM_NORMAL);
-	if (!cache->io_queues)
-		return -ENOMEM;
-
-	return 0;
-}
-
-void ocf_free_queues(struct ocf_cache *cache)
-{
-	env_free(cache->io_queues);
-	cache->io_queues_no = 0;
-	cache->io_queues = NULL;
-}
-
-static void ocf_init_queue(struct ocf_queue *q)
+static void ocf_init_queue(ocf_queue_t q)
 {
 	env_atomic_set(&q->io_no, 0);
 	env_spinlock_init(&q->io_list_lock);
 	INIT_LIST_HEAD(&q->io_list);
+	env_atomic_set(&q->ref_count, 1);
 }
 
-int ocf_start_queues(ocf_cache_t cache)
+int ocf_queue_create(ocf_cache_t cache, ocf_queue_t *queue,
+		const struct ocf_queue_ops *ops)
 {
-	int id, result = 0;
-	struct ocf_queue *q;
+	ocf_queue_t tmp_queue;
 
-	for (id = 0; id < cache->io_queues_no; id++) {
-		q = &cache->io_queues[id];
-		q->cache = cache;
-		q->id = id;
-		ocf_init_queue(q);
-		result = ctx_queue_init(cache->owner, q);
-		if (result)
-			break;
-	}
-	if (result) {
-		while (id) {
-			ctx_queue_stop(cache->owner,
-					&cache->io_queues[--id]);
-		}
-	}
+	OCF_CHECK_NULL(cache);
 
-	return result;
+	tmp_queue = env_zalloc(sizeof(*tmp_queue), ENV_MEM_NORMAL);
+	if (!tmp_queue)
+		return -ENOMEM;
+
+	tmp_queue->cache = cache;
+	ocf_init_queue(tmp_queue);
+
+	tmp_queue->ops = ops;
+
+	list_add(&tmp_queue->list, &cache->io_queues);
+
+	*queue = tmp_queue;
+
+	return 0;
 }
 
-void ocf_stop_queues(ocf_cache_t cache)
+void ocf_queue_get(ocf_queue_t queue)
 {
-	int i;
-	struct ocf_queue *curr;
+	OCF_CHECK_NULL(queue);
 
-	ocf_cache_wait_for_io_finish(cache);
+	env_atomic_inc(&queue->ref_count);
+}
 
-	/* Stop IO threads. */
-	for (i = 0 ; i < cache->io_queues_no; i++) {
-		curr = &cache->io_queues[i];
-		ctx_queue_stop(cache->owner, curr);
+void ocf_queue_put(ocf_queue_t queue)
+{
+	OCF_CHECK_NULL(queue);
+
+	if (env_atomic_dec_return(&queue->ref_count) == 0) {
+		list_del(&queue->list);
+		queue->ops->stop(queue);
+		env_free(queue);
 	}
 }
 
@@ -92,7 +77,7 @@ void ocf_io_handle(struct ocf_io *io, void *opaque)
 void ocf_queue_run_single(ocf_queue_t q)
 {
 	struct ocf_request *io_req = NULL;
-	struct ocf_cache *cache;
+	ocf_cache_t cache;
 
 	OCF_CHECK_NULL(q);
 
@@ -145,20 +130,3 @@ ocf_cache_t ocf_queue_get_cache(ocf_queue_t q)
 	OCF_CHECK_NULL(q);
 	return q->cache;
 }
-
-uint32_t ocf_queue_get_id(ocf_queue_t q)
-{
-	OCF_CHECK_NULL(q);
-	return q->id;
-}
-
-int ocf_cache_get_queue(ocf_cache_t cache, unsigned id, ocf_queue_t *q)
-{
-	OCF_CHECK_NULL(cache);
-
-	if (!q || id >= cache->io_queues_no)
-		return -OCF_ERR_INVAL;
-
-	*q = &cache->io_queues[id];
-	return 0;
-}
diff --git a/src/ocf_queue_priv.h b/src/ocf_queue_priv.h
index 9989b11..6a7f4df 100644
--- a/src/ocf_queue_priv.h
+++ b/src/ocf_queue_priv.h
@@ -9,11 +9,12 @@
 #include "ocf_env.h"
 
 struct ocf_queue {
-	struct ocf_cache *cache;
-	uint32_t id;
+	ocf_cache_t cache;
 
 	env_atomic io_no;
 
+	env_atomic ref_count;
+
 	struct list_head io_list;
 	env_spinlock io_list_lock;
 
@@ -23,15 +24,19 @@ struct ocf_queue {
 	/* Tracing stop request */
 	env_atomic trace_stop;
 
+	struct list_head list;
+
+	const struct ocf_queue_ops *ops;
+
 	void *priv;
 };
 
-int ocf_alloc_queues(struct ocf_cache *cache);
-
-int ocf_start_queues(struct ocf_cache *cache);
-
-void ocf_stop_queues(struct ocf_cache *cache);
-
-void ocf_free_queues(struct ocf_cache *cache);
+static inline void ocf_queue_kick(ocf_queue_t queue, bool allow_sync)
+{
+	if (allow_sync && queue->ops->kick_sync)
+		queue->ops->kick_sync(queue);
+	else
+		queue->ops->kick(queue);
+}
 
 #endif
diff --git a/src/ocf_request.h b/src/ocf_request.h
index e3f422d..030e479 100644
--- a/src/ocf_request.h
+++ b/src/ocf_request.h
@@ -120,7 +120,7 @@ struct ocf_request {
 	env_atomic master_remaining;
 	/*!< Atomic counter for core device */
 
-	struct ocf_cache *cache;
+	ocf_cache_t cache;
 	/*!< Handle to cache instance */
 
 	const struct ocf_io_if *io_if;
@@ -165,8 +165,8 @@ struct ocf_request {
 	uint32_t alloc_core_line_count;
 	/*! Core line count for which request was initially allocated */
 
-	uint32_t io_queue;
-	/*!< I/O queue id for which request should be submitted */
+	ocf_queue_t io_queue;
+	/*!< I/O queue handle for which request should be submitted */
 
 	int error;
 	/*!< This filed indicates an error for OCF request */
diff --git a/src/ocf_trace.c b/src/ocf_trace.c
index 314fe8a..3f173f9 100644
--- a/src/ocf_trace.c
+++ b/src/ocf_trace.c
@@ -13,7 +13,7 @@
 
 struct core_trace_visitor_ctx {
 	ocf_cache_t cache;
-	uint32_t io_queue;
+	ocf_queue_t io_queue;
 };
 
 static int _ocf_core_desc(ocf_core_t core, void  *ctx)
@@ -31,13 +31,13 @@ static int _ocf_core_desc(ocf_core_t core, void  *ctx)
 	core_desc.core_size = ocf_volume_get_length(
 			ocf_core_get_volume(core));
 
-	ocf_trace_push(cache, visitor_ctx->io_queue,
+	ocf_trace_push(visitor_ctx->io_queue,
 			&core_desc, sizeof(core_desc));
 
 	return 0;
 }
 
-static int _ocf_trace_cache_info(ocf_cache_t cache, uint32_t io_queue)
+static int _ocf_trace_cache_info(ocf_cache_t cache, ocf_queue_t io_queue)
 {
 	struct ocf_event_cache_desc cache_desc;
 	int retval;
@@ -62,9 +62,8 @@ static int _ocf_trace_cache_info(ocf_cache_t cache, uint32_t io_queue)
 
 	cache_desc.cores_no = ocf_cache_get_core_count(cache);
 	cache_desc.version = OCF_EVENT_VERSION;
-	cache_desc.io_queues_no = cache->io_queues_no;
 
-	ocf_trace_push(cache, io_queue, &cache_desc, sizeof(cache_desc));
+	ocf_trace_push(io_queue, &cache_desc, sizeof(cache_desc));
 
 	visitor_ctx.cache = cache;
 	visitor_ctx.io_queue = io_queue;
@@ -77,8 +76,8 @@ static int _ocf_trace_cache_info(ocf_cache_t cache, uint32_t io_queue)
 int ocf_mngt_start_trace(ocf_cache_t cache, void *trace_ctx,
 	ocf_trace_callback_t trace_callback)
 {
-	int queue, result;
-	uint32_t i;
+	ocf_queue_t queue;
+	int result;
 
 	OCF_CHECK_NULL(cache);
 
@@ -96,11 +95,12 @@ int ocf_mngt_start_trace(ocf_cache_t cache, void *trace_ctx,
 	cache->trace.trace_ctx = trace_ctx;
 
 	// Reset trace stop flag
-	for (queue = 0; queue < cache->io_queues_no; queue++)
-		env_atomic_set(&cache->io_queues[queue].trace_stop, 0);
+	list_for_each_entry(queue, &cache->io_queues, list) {
+		env_atomic_set(&queue->trace_stop, 0);
+	}
 
-	for (i = 0; i < cache->io_queues_no; i++) {
-		result = _ocf_trace_cache_info(cache, i);
+	list_for_each_entry(queue, &cache->io_queues, list) {
+		result = _ocf_trace_cache_info(cache, queue);
 		if (result) {
 			cache->trace.trace_callback = NULL;
 			return result;
@@ -115,7 +115,7 @@ int ocf_mngt_start_trace(ocf_cache_t cache, void *trace_ctx,
 
 int ocf_mngt_stop_trace(ocf_cache_t cache)
 {
-	int queue;
+	ocf_queue_t queue;
 
 	OCF_CHECK_NULL(cache);
 
@@ -127,9 +127,8 @@ int ocf_mngt_stop_trace(ocf_cache_t cache)
 	}
 
 	// Set trace stop flag
-	for (queue = 0; queue < cache->io_queues_no; queue++) {
-		env_atomic_set(&cache->io_queues[queue].trace_stop,
-				OCF_TRACING_STOP);
+	list_for_each_entry(queue, &cache->io_queues, list) {
+		env_atomic_set(&queue->trace_stop, OCF_TRACING_STOP);
 	}
 
 	cache->trace.trace_callback = NULL;
diff --git a/src/ocf_trace_priv.h b/src/ocf_trace_priv.h
index a9645bc..3e68b3a 100644
--- a/src/ocf_trace_priv.h
+++ b/src/ocf_trace_priv.h
@@ -16,10 +16,10 @@
 
 static inline bool ocf_is_trace_ongoing(ocf_cache_t cache)
 {
-	int i;
+	ocf_queue_t q;
 
-	for (i = 0; i < cache->io_queues_no; i++) {
-		if (env_atomic64_read(&cache->io_queues[i].trace_ref_cntr))
+	list_for_each_entry(q, &cache->io_queues, list) {
+		if (env_atomic64_read(&q->trace_ref_cntr))
 			return true;
 	}
 
@@ -66,20 +66,24 @@ static inline void ocf_trace_prep_io_event(struct ocf_event_io *ev,
 	ev->io_class = rq->io->io_class;
 }
 
-static inline void ocf_trace_push(ocf_cache_t cache, uint32_t io_queue,
-	void *trace, uint32_t size)
+static inline void ocf_trace_push(ocf_queue_t queue, void *trace, uint32_t size)
 {
+	ocf_cache_t cache;
 	ocf_trace_callback_t trace_callback;
 	void *trace_ctx;
 
+	OCF_CHECK_NULL(queue);
+
+	cache = ocf_queue_get_cache(queue);
+
 	if (cache->trace.trace_callback == NULL)
 		return;
 
-	env_atomic64_inc(&cache->io_queues[io_queue].trace_ref_cntr);
+	env_atomic64_inc(&queue->trace_ref_cntr);
 
-	if (env_atomic_read(&cache->io_queues[io_queue].trace_stop)) {
+	if (env_atomic_read(&queue->trace_stop)) {
 		// Tracing stop was requested
-		env_atomic64_dec(&cache->io_queues[io_queue].trace_ref_cntr);
+		env_atomic64_dec(&queue->trace_ref_cntr);
 		return;
 	}
 
@@ -93,10 +97,10 @@ static inline void ocf_trace_push(ocf_cache_t cache, uint32_t io_queue,
 	trace_ctx = cache->trace.trace_ctx;
 
 	if (trace_callback && trace_ctx) {
-		trace_callback(cache, trace_ctx, io_queue, trace, size);
+		trace_callback(cache, trace_ctx, queue, trace, size);
 	}
 
-	env_atomic64_dec(&cache->io_queues[io_queue].trace_ref_cntr);
+	env_atomic64_dec(&queue->trace_ref_cntr);
 }
 
 static inline void ocf_trace_io(struct ocf_core_io *io, ocf_event_operation_t dir, ocf_cache_t cache)
@@ -110,7 +114,7 @@ static inline void ocf_trace_io(struct ocf_core_io *io, ocf_event_operation_t di
 	rq  = io->req;
 	ocf_trace_prep_io_event(&ev, io, dir);
 
-	ocf_trace_push(cache, rq->io_queue, &ev, sizeof(ev));
+	ocf_trace_push(rq->io_queue, &ev, sizeof(ev));
 }
 
 static inline void ocf_trace_io_cmpl(struct ocf_core_io *io, ocf_cache_t cache)
@@ -129,7 +133,7 @@ static inline void ocf_trace_io_cmpl(struct ocf_core_io *io, ocf_cache_t cache)
 	ev.rsid = io->sid;
 	ev.is_hit = ocf_engine_is_hit(rq);
 
-	ocf_trace_push(cache, rq->io_queue, &ev, sizeof(ev));
+	ocf_trace_push(rq->io_queue, &ev, sizeof(ev));
 }
 
 #endif /* __OCF_TRACE_PRIV_H__ */
diff --git a/src/utils/utils_cleaner.c b/src/utils/utils_cleaner.c
index eedc92e..db2959f 100644
--- a/src/utils/utils_cleaner.c
+++ b/src/utils/utils_cleaner.c
@@ -37,8 +37,8 @@
 static struct ocf_request *_ocf_cleaner_alloc_req(struct ocf_cache *cache,
 		uint32_t count, const struct ocf_cleaner_attribs *attribs)
 {
-	struct ocf_request *req = ocf_req_new_extended(cache, 0, 0,
-			count * ocf_line_size(cache), OCF_READ);
+	struct ocf_request *req = ocf_req_new_extended(attribs->io_queue, NULL,
+			0, count * ocf_line_size(cache), OCF_READ);
 	int ret;
 
 	if (!req)
@@ -62,8 +62,6 @@ static struct ocf_request *_ocf_cleaner_alloc_req(struct ocf_cache *cache,
 		return NULL;
 	}
 
-	req->io_queue = attribs->io_queue;
-
 	return req;
 }
 
diff --git a/src/utils/utils_cleaner.h b/src/utils/utils_cleaner.h
index 8e09fe5..b2f3579 100644
--- a/src/utils/utils_cleaner.h
+++ b/src/utils/utils_cleaner.h
@@ -43,7 +43,7 @@ struct ocf_cleaner_attribs {
 		 * to iterate over items
 		 */
 
-	uint32_t io_queue;
+	ocf_queue_t io_queue;
 };
 
 /**
diff --git a/src/utils/utils_req.c b/src/utils/utils_req.c
index ff4d067..4a82fff 100644
--- a/src/utils/utils_req.c
+++ b/src/utils/utils_req.c
@@ -8,6 +8,7 @@
 #include "utils_cache_line.h"
 #include "../ocf_request.h"
 #include "../ocf_cache_priv.h"
+#include "../ocf_queue_priv.h"
 
 #define OCF_UTILS_RQ_DEBUG 0
 
@@ -165,10 +166,11 @@ static void start_cache_req(struct ocf_request *req)
 	}
 }
 
-struct ocf_request *ocf_req_new(struct ocf_cache *cache,
-		ocf_core_id_t core_id, uint64_t addr, uint32_t bytes, int rw)
+struct ocf_request *ocf_req_new(ocf_queue_t queue, ocf_core_t core,
+		uint64_t addr, uint32_t bytes, int rw)
 {
 	uint64_t core_line_first, core_line_last, core_line_count;
+	ocf_cache_t cache = queue->cache;
 	struct ocf_request *req;
 	env_allocator *allocator;
 
@@ -197,14 +199,17 @@ struct ocf_request *ocf_req_new(struct ocf_cache *cache,
 
 	OCF_DEBUG_TRACE(cache);
 
+	ocf_queue_get(queue);
+	req->io_queue = queue;
+
+	/* TODO: Store core pointer instead of id */
+	req->core_id = core ? ocf_core_get_id(core) : 0;
 	req->cache = cache;
 
 	env_atomic_inc(&cache->pending_requests);
 	start_cache_req(req);
 
-	req->io_queue = 0;
 	env_atomic_set(&req->ref_count, 1);
-	req->core_id = core_id;
 
 	req->byte_position = addr;
 	req->byte_length = bytes;
@@ -232,12 +237,12 @@ int ocf_req_alloc_map(struct ocf_request *req)
 	return 0;
 }
 
-struct ocf_request *ocf_req_new_extended(struct ocf_cache *cache,
-		ocf_core_id_t core_id, uint64_t addr, uint32_t bytes, int rw)
+struct ocf_request *ocf_req_new_extended(ocf_queue_t queue, ocf_core_t core,
+		uint64_t addr, uint32_t bytes, int rw)
 {
 	struct ocf_request *req;
 
-	req = ocf_req_new(cache, core_id, addr, bytes, rw);
+	req = ocf_req_new(queue, core, addr, bytes, rw);
 
 	if (likely(req) && ocf_req_alloc_map(req)) {
 		ocf_req_put(req);
@@ -247,14 +252,13 @@ struct ocf_request *ocf_req_new_extended(struct ocf_cache *cache,
 	return req;
 }
 
-struct ocf_request *ocf_req_new_discard(struct ocf_cache *cache,
-		ocf_core_id_t core_id, uint64_t addr, uint32_t bytes, int rw)
+struct ocf_request *ocf_req_new_discard(ocf_queue_t queue, ocf_core_t core,
+		uint64_t addr, uint32_t bytes, int rw)
 {
 	struct ocf_request *req;
 
-	req = ocf_req_new_extended(cache, core_id, addr,
-			OCF_MIN(bytes, MAX_TRIM_RQ_SIZE),rw);
-
+	req = ocf_req_new_extended(queue, core, addr,
+			OCF_MIN(bytes, MAX_TRIM_RQ_SIZE), rw);
 	if (!req)
 		return NULL;
 
@@ -279,6 +283,8 @@ void ocf_req_put(struct ocf_request *req)
 	if (env_atomic_dec_return(&req->ref_count))
 		return;
 
+	ocf_queue_put(req->io_queue);
+
 	OCF_DEBUG_TRACE(req->cache);
 
 	if (!req->d2c && !env_atomic_dec_return(
diff --git a/src/utils/utils_req.h b/src/utils/utils_req.h
index 63c9a17..1d64154 100644
--- a/src/utils/utils_req.h
+++ b/src/utils/utils_req.h
@@ -33,16 +33,16 @@ void ocf_req_allocator_deinit(struct ocf_ctx *ocf_ctx);
 /**
  * @brief Allocate new OCF request
  *
- * @param cache - OCF cache instance
- * @param core_id - Core id
+ * @param queue - I/O queue handle
+ * @param core - OCF core instance
  * @param addr - LBA of request
  * @param bytes - number of bytes of request
  * @param rw - Read or Write
  *
  * @return new OCF request
  */
-struct ocf_request *ocf_req_new(struct ocf_cache *cache,
-		ocf_core_id_t core_id, uint64_t addr, uint32_t bytes, int rw);
+struct ocf_request *ocf_req_new(ocf_queue_t queue, ocf_core_t core,
+		uint64_t addr, uint32_t bytes, int rw);
 
 /**
  * @brief Allocate OCF request map
@@ -57,8 +57,8 @@ int ocf_req_alloc_map(struct ocf_request *req);
 /**
  * @brief Allocate new OCF request with NOIO map allocation for huge request
  *
- * @param cache - OCF cache instance
- * @param core_id - Core id
+ * @param queue - I/O queue handle
+ * @param core - OCF core instance
  * @param addr - LBA of request
  * @param bytes - number of bytes of request
  * @param rw - Read or Write
@@ -66,22 +66,22 @@ int ocf_req_alloc_map(struct ocf_request *req);
  * @return new OCF request
  */
 
-struct ocf_request *ocf_req_new_extended(struct ocf_cache *cache,
-		ocf_core_id_t core_id, uint64_t addr, uint32_t bytes, int rw);
+struct ocf_request *ocf_req_new_extended(ocf_queue_t queue, ocf_core_t core,
+		uint64_t addr, uint32_t bytes, int rw);
 
 /**
  * @brief Allocate new OCF request for DISCARD operation
  *
- * @param cache - OCF cache instance
- * @param core_id - Core id
+ * @param queue - I/O queue handle
+ * @param core - OCF core instance
  * @param addr - LBA of request
  * @param bytes - number of bytes of request
  * @param rw - Read or Write
  *
  * @return new OCF request
  */
-struct ocf_request *ocf_req_new_discard(struct ocf_cache *cache,
-		ocf_core_id_t core_id, uint64_t addr, uint32_t bytes, int rw);
+struct ocf_request *ocf_req_new_discard(ocf_queue_t queue, ocf_core_t core,
+		uint64_t addr, uint32_t bytes, int rw);
 
 /**
  * @brief Get number of allocated requests
diff --git a/tests/unit/tests/cleaning/cleaning.c/ocf_cleaner_run_test.c b/tests/unit/tests/cleaning/cleaning.c/ocf_cleaner_run_test.c
index eaf32a9..72b4613 100644
--- a/tests/unit/tests/cleaning/cleaning.c/ocf_cleaner_run_test.c
+++ b/tests/unit/tests/cleaning/cleaning.c/ocf_cleaner_run_test.c
@@ -160,6 +160,11 @@ void __wrap_cleaning_policy_alru_get_cleaning_parameters(ocf_cache_t cache,
 
 }
 
+void __wrap_ocf_queue_get(ocf_queue_t queue)
+{
+
+}
+
 int __wrap_cleaning_alru_perform_cleaning(struct ocf_cache *cache, ocf_cleaner_end_t cmpl)
 {
 	function_called();
@@ -252,7 +257,7 @@ static void ocf_cleaner_run_test01(void **state)
 
 	ocf_cleaner_set_cmpl(&cache.cleaner, cleaner_complete);
 
-	ocf_cleaner_run(&cache.cleaner);
+	ocf_cleaner_run(&cache.cleaner, 0xdeadbeef);
 
 	/* Release allocated memory if allocated with test_* functions */