Queue visitor API

Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>

inc/ocf_queue.h

@@ -72,6 +72,28 @@ int ocf_queue_create(ocf_cache_t cache, ocf_queue_t *queue,
 int ocf_queue_create_mngt(ocf_cache_t cache, ocf_queue_t *queue,
 		const struct ocf_queue_ops *ops);
 
+/**
+ * @brief Queue visitor function
+ * @param[in] queue Queue handle
+ * @param[in] ctx Visitor function context
+ *
+ * @return Zero on success, otherwise error code
+ */
+typedef int (*ocf_cache_queue_visitor_t)(ocf_queue_t queue, void *ctx);
+
+/**
+ * @brief Call @visitor for every IO queue
+ *
+ * @param[in] cache Cache instance
+ * @param[in] visitor Function to be called on every queue.
+ *		The visitor function is called in atomic context
+ * @param[in] ctx Context to be passes to @visitor
+ *
+ * @return Zero on success, otherwise error code
+ */
+int ocf_queue_visit(ocf_cache_t cache, ocf_cache_queue_visitor_t visitor,
+		void *ctx);
+
 /**
  * @brief Increase reference counter in queue
  *

src/ocf_queue.c

@@ -78,6 +78,26 @@ int ocf_queue_create(ocf_cache_t cache, ocf_queue_t *queue,
 	return 0;
 }
 
+int ocf_queue_visit(ocf_cache_t cache, ocf_cache_queue_visitor_t visitor,
+		void *ctx)
+{
+	ocf_queue_t queue;
+	int result = 0;
+	unsigned long flags = 0;
+
+	env_spinlock_lock_irqsave(&cache->io_queues_lock, flags);
+
+	list_for_each_entry(queue, &cache->io_queues, list) {
+		result = visitor(queue, ctx);
+		if (result)
+			break;
+	}
+
+	env_spinlock_unlock_irqrestore(&cache->io_queues_lock, flags);
+
+	return result;
+}
+
 int ocf_queue_create_mngt(ocf_cache_t cache, ocf_queue_t *queue,
 		const struct ocf_queue_ops *ops)
 {