/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef RQ_QOS_H
  #define RQ_QOS_H
  
  #include <linux/kernel.h>
  #include <linux/blkdev.h>
  #include <linux/blk_types.h>
  #include <linux/atomic.h>
  #include <linux/wait.h>

  #include "blk-mq-debugfs.h"
  
  struct blk_mq_debugfs_attr;

  enum rq_qos_id {
  	RQ_QOS_WBT,

  	RQ_QOS_LATENCY,

  	RQ_QOS_COST,

  };
  
  struct rq_wait {
  	wait_queue_head_t wait;
  	atomic_t inflight;
  };
  
  struct rq_qos {
  	struct rq_qos_ops *ops;
  	struct request_queue *q;
  	enum rq_qos_id id;
  	struct rq_qos *next;

  #ifdef CONFIG_BLK_DEBUG_FS
  	struct dentry *debugfs_dir;
  #endif

  };
  
  struct rq_qos_ops {

  	void (*throttle)(struct rq_qos *, struct bio *);

  	void (*track)(struct rq_qos *, struct request *, struct bio *);

  	void (*merge)(struct rq_qos *, struct request *, struct bio *);

  	void (*issue)(struct rq_qos *, struct request *);
  	void (*requeue)(struct rq_qos *, struct request *);
  	void (*done)(struct rq_qos *, struct request *);

  	void (*done_bio)(struct rq_qos *, struct bio *);

  	void (*cleanup)(struct rq_qos *, struct bio *);

  	void (*queue_depth_changed)(struct rq_qos *);

  	void (*exit)(struct rq_qos *);

  	const struct blk_mq_debugfs_attr *debugfs_attrs;

  };
  
  struct rq_depth {
  	unsigned int max_depth;
  
  	int scale_step;
  	bool scaled_max;
  
  	unsigned int queue_depth;
  	unsigned int default_depth;
  };
  
  static inline struct rq_qos *rq_qos_id(struct request_queue *q,
  				       enum rq_qos_id id)
  {
  	struct rq_qos *rqos;
  	for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
  		if (rqos->id == id)
  			break;
  	}
  	return rqos;
  }
  
  static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
  {
  	return rq_qos_id(q, RQ_QOS_WBT);
  }
  
  static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q)
  {

  	return rq_qos_id(q, RQ_QOS_LATENCY);

  }

  static inline const char *rq_qos_id_to_name(enum rq_qos_id id)
  {
  	switch (id) {
  	case RQ_QOS_WBT:
  		return "wbt";

  	case RQ_QOS_LATENCY:
  		return "latency";

  	case RQ_QOS_COST:
  		return "cost";

  	}
  	return "unknown";
  }

  static inline void rq_wait_init(struct rq_wait *rq_wait)
  {
  	atomic_set(&rq_wait->inflight, 0);
  	init_waitqueue_head(&rq_wait->wait);
  }
  
  static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
  {
  	rqos->next = q->rq_qos;
  	q->rq_qos = rqos;

  
  	if (rqos->ops->debugfs_attrs)
  		blk_mq_debugfs_register_rqos(rqos);

  }
  
  static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
  {

  	struct rq_qos **cur;
  
  	for (cur = &q->rq_qos; *cur; cur = &(*cur)->next) {
  		if (*cur == rqos) {
  			*cur = rqos->next;

  			break;
  		}

  	}

  
  	blk_mq_debugfs_unregister_rqos(rqos);

  }

  typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data);
  typedef void (cleanup_cb_t)(struct rq_wait *rqw, void *private_data);
  
  void rq_qos_wait(struct rq_wait *rqw, void *private_data,
  		 acquire_inflight_cb_t *acquire_inflight_cb,
  		 cleanup_cb_t *cleanup_cb);

  bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit);

  bool rq_depth_scale_up(struct rq_depth *rqd);
  bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);

  bool rq_depth_calc_max_depth(struct rq_depth *rqd);

  void __rq_qos_cleanup(struct rq_qos *rqos, struct bio *bio);
  void __rq_qos_done(struct rq_qos *rqos, struct request *rq);
  void __rq_qos_issue(struct rq_qos *rqos, struct request *rq);
  void __rq_qos_requeue(struct rq_qos *rqos, struct request *rq);
  void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
  void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);

  void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);

  void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);

  void __rq_qos_queue_depth_changed(struct rq_qos *rqos);

  
  static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
  {
  	if (q->rq_qos)
  		__rq_qos_cleanup(q->rq_qos, bio);
  }
  
  static inline void rq_qos_done(struct request_queue *q, struct request *rq)
  {
  	if (q->rq_qos)
  		__rq_qos_done(q->rq_qos, rq);
  }
  
  static inline void rq_qos_issue(struct request_queue *q, struct request *rq)
  {
  	if (q->rq_qos)
  		__rq_qos_issue(q->rq_qos, rq);
  }
  
  static inline void rq_qos_requeue(struct request_queue *q, struct request *rq)
  {
  	if (q->rq_qos)
  		__rq_qos_requeue(q->rq_qos, rq);
  }
  
  static inline void rq_qos_done_bio(struct request_queue *q, struct bio *bio)
  {
  	if (q->rq_qos)
  		__rq_qos_done_bio(q->rq_qos, bio);
  }
  
  static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
  {

  	/*
  	 * BIO_TRACKED lets controllers know that a bio went through the
  	 * normal rq_qos path.
  	 */
  	bio_set_flag(bio, BIO_TRACKED);

  	if (q->rq_qos)
  		__rq_qos_throttle(q->rq_qos, bio);
  }
  
  static inline void rq_qos_track(struct request_queue *q, struct request *rq,
  				struct bio *bio)
  {
  	if (q->rq_qos)
  		__rq_qos_track(q->rq_qos, rq, bio);
  }

  static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
  				struct bio *bio)
  {
  	if (q->rq_qos)
  		__rq_qos_merge(q->rq_qos, rq, bio);
  }

  static inline void rq_qos_queue_depth_changed(struct request_queue *q)
  {
  	if (q->rq_qos)
  		__rq_qos_queue_depth_changed(q->rq_qos);
  }

  void rq_qos_exit(struct request_queue *);

  #endif