+/**
+ * struct blk_mq_tag_set - tag set that can be shared between request queues
+ * @map: One or more ctx -> hctx mappings. One map exists for each
+ * hardware queue type (enum hctx_type) that the driver wishes
+ * to support. There are no restrictions on maps being of the
+ * same size, and it's perfectly legal to share maps between
+ * types.
+ * @nr_maps: Number of elements in the @map array. A number in the range
+ * [1, HCTX_MAX_TYPES].
+ * @ops: Pointers to functions that implement block driver behavior.
+ * @nr_hw_queues: Number of hardware queues supported by the block driver that
+ * owns this data structure.
+ * @queue_depth: Number of tags per hardware queue, reserved tags included.
+ * @reserved_tags: Number of tags to set aside for BLK_MQ_REQ_RESERVED tag
+ * allocations.
+ * @cmd_size: Number of additional bytes to allocate per request. The block
+ * driver owns these additional bytes.
+ * @numa_node: NUMA node the storage adapter has been connected to.
+ * @timeout: Request processing timeout in jiffies.
+ * @flags: Zero or more BLK_MQ_F_* flags.
+ * @driver_data: Pointer to data owned by the block driver that created this
+ * tag set.
+ * @tags: Tag sets. One tag set per hardware queue. Has @nr_hw_queues
+ * elements.
+ * @tag_list_lock: Serializes tag_list accesses.
+ * @tag_list: List of the request queues that use this tag set. See also
+ * request_queue.tag_set_list.
+ */