#ifndef INT_BLK_MQ_TAG_H
  #define INT_BLK_MQ_TAG_H

  #include "blk-mq.h"

  enum {
  	BT_WAIT_QUEUES	= 8,
  	BT_WAIT_BATCH	= 8,
  };
  
  struct bt_wait_state {
  	atomic_t wait_cnt;
  	wait_queue_head_t wait;
  } ____cacheline_aligned_in_smp;

  #define TAG_TO_INDEX(bt, tag)	((tag) >> (bt)->bits_per_word)
  #define TAG_TO_BIT(bt, tag)	((tag) & ((1 << (bt)->bits_per_word) - 1))

  struct blk_mq_bitmap_tags {
  	unsigned int depth;
  	unsigned int wake_cnt;

  	unsigned int bits_per_word;

  	unsigned int map_nr;

  	struct blk_align_bitmap *map;

  	atomic_t wake_index;

  	struct bt_wait_state *bs;
  };

  
  /*
   * Tag address space map.
   */
  struct blk_mq_tags {
  	unsigned int nr_tags;
  	unsigned int nr_reserved_tags;

  	atomic_t active_queues;

  	struct blk_mq_bitmap_tags bitmap_tags;
  	struct blk_mq_bitmap_tags breserved_tags;

  
  	struct request **rqs;
  	struct list_head page_list;

  
  	int alloc_policy;

  	cpumask_var_t cpumask;

  };

  extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int reserved_tags, int node, int alloc_policy);

  extern void blk_mq_free_tags(struct blk_mq_tags *tags);

  extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data);

  extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, unsigned int *last_tag);

  extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
  extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);

  extern void blk_mq_tag_init_last_tag(struct blk_mq_tags *tags, unsigned int *last_tag);

  extern int blk_mq_tag_update_depth(struct blk_mq_tags *tags, unsigned int depth);

  extern void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool);

  void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
  		void *priv);

  
  enum {
  	BLK_MQ_TAG_CACHE_MIN	= 1,
  	BLK_MQ_TAG_CACHE_MAX	= 64,
  };
  
  enum {
  	BLK_MQ_TAG_FAIL		= -1U,
  	BLK_MQ_TAG_MIN		= BLK_MQ_TAG_CACHE_MIN,
  	BLK_MQ_TAG_MAX		= BLK_MQ_TAG_FAIL - 1,
  };

  extern bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *);
  extern void __blk_mq_tag_idle(struct blk_mq_hw_ctx *);
  
  static inline bool blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
  {
  	if (!(hctx->flags & BLK_MQ_F_TAG_SHARED))
  		return false;
  
  	return __blk_mq_tag_busy(hctx);
  }
  
  static inline void blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
  {
  	if (!(hctx->flags & BLK_MQ_F_TAG_SHARED))
  		return;
  
  	__blk_mq_tag_idle(hctx);
  }

  /*
   * This helper should only be used for flush request to share tag
   * with the request cloned from, and both the two requests can't be
   * in flight at the same time. The caller has to make sure the tag
   * can't be freed.
   */
  static inline void blk_mq_tag_set_rq(struct blk_mq_hw_ctx *hctx,
  		unsigned int tag, struct request *rq)
  {
  	hctx->tags->rqs[tag] = rq;
  }

  #endif