text: /* SPDX-License-Identifier: GPL-2.0 */
  #ifndef BLK_INTERNAL_H
  #define BLK_INTERNAL_H
  
  #include <linux/idr.h>
  #include <linux/blk-mq.h>
  #include <xen/xen.h>
  #include "blk-mq.h"
  #include "blk-mq-sched.h"
  
  /* Max future timer expiry for timeouts */
  #define BLK_MAX_TIMEOUT		(5 * HZ)
  
  #ifdef CONFIG_DEBUG_FS
  extern struct dentry *blk_debugfs_root;
  #endif
  
  struct blk_flush_queue {
  	unsigned int		flush_queue_delayed:1;
  	unsigned int		flush_pending_idx:1;
  	unsigned int		flush_running_idx:1;
  	unsigned long		flush_pending_since;
  	struct list_head	flush_queue[2];
  	struct list_head	flush_data_in_flight;
  	struct request		*flush_rq;
  
  	/*
  	 * flush_rq shares tag with this rq, both can't be active
  	 * at the same time
  	 */
  	struct request		*orig_rq;
  	spinlock_t		mq_flush_lock;
  };
  
  extern struct kmem_cache *blk_requestq_cachep;
  extern struct kobj_type blk_queue_ktype;
  extern struct ida blk_queue_ida;
  
  static inline struct blk_flush_queue *
  blk_get_flush_queue(struct request_queue *q, struct blk_mq_ctx *ctx)
  {
  	return blk_mq_map_queue(q, REQ_OP_FLUSH, ctx)->fq;
  }
  
  static inline void __blk_get_queue(struct request_queue *q)
  {
  	kobject_get(&q->kobj);
  }
  
  struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
  		int node, int cmd_size, gfp_t flags);
  void blk_free_flush_queue(struct blk_flush_queue *q);
  
  void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
  			struct bio *bio);
  void blk_freeze_queue(struct request_queue *q);
  
  static inline void blk_queue_enter_live(struct request_queue *q)
  {
  	/*
  	 * Given that running in generic_make_request() context
  	 * guarantees that a live reference against q_usage_counter has
  	 * been established, further references under that same context
  	 * need not check that the queue has been frozen (marked dead).
  	 */
  	percpu_ref_get(&q->q_usage_counter);
  }
  
  static inline bool biovec_phys_mergeable(struct request_queue *q,
  		struct bio_vec *vec1, struct bio_vec *vec2)
  {
  	unsigned long mask = queue_segment_boundary(q);
  	phys_addr_t addr1 = page_to_phys(vec1->bv_page) + vec1->bv_offset;
  	phys_addr_t addr2 = page_to_phys(vec2->bv_page) + vec2->bv_offset;
  
  	if (addr1 + vec1->bv_len != addr2)
  		return false;
  	if (xen_domain() && !xen_biovec_phys_mergeable(vec1, vec2->bv_page))
  		return false;
  	if ((addr1 | mask) != ((addr2 + vec2->bv_len - 1) | mask))
  		return false;
  	return true;
  }
  
  static inline bool __bvec_gap_to_prev(struct request_queue *q,
  		struct bio_vec *bprv, unsigned int offset)
  {
  	return (offset & queue_virt_boundary(q)) ||
  		((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q));
  }
  
  /*
   * Check if adding a bio_vec after bprv with offset would create a gap in
   * the SG list. Most drivers don't care about this, but some do.
   */
  static inline bool bvec_gap_to_prev(struct request_queue *q,
  		struct bio_vec *bprv, unsigned int offset)
  {
  	if (!queue_virt_boundary(q))
  		return false;
  	return __bvec_gap_to_prev(q, bprv, offset);
  }
  
  #ifdef CONFIG_BLK_DEV_INTEGRITY
  void blk_flush_integrity(void);
  bool __bio_integrity_endio(struct bio *);
  static inline bool bio_integrity_endio(struct bio *bio)
  {
  	if (bio_integrity(bio))
  		return __bio_integrity_endio(bio);
  	return true;
  }
  
  static inline bool integrity_req_gap_back_merge(struct request *req,
  		struct bio *next)
  {
  	struct bio_integrity_payload *bip = bio_integrity(req->bio);
  	struct bio_integrity_payload *bip_next = bio_integrity(next);
  
  	return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
  				bip_next->bip_vec[0].bv_offset);
  }
  
  static inline bool integrity_req_gap_front_merge(struct request *req,
  		struct bio *bio)
  {
  	struct bio_integrity_payload *bip = bio_integrity(bio);
  	struct bio_integrity_payload *bip_next = bio_integrity(req->bio);
  
  	return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
  				bip_next->bip_vec[0].bv_offset);
  }
  #else /* CONFIG_BLK_DEV_INTEGRITY */
  static inline bool integrity_req_gap_back_merge(struct request *req,
  		struct bio *next)
  {
  	return false;
  }
  static inline bool integrity_req_gap_front_merge(struct request *req,
  		struct bio *bio)
  {
  	return false;
  }
  
  static inline void blk_flush_integrity(void)
  {
  }
  static inline bool bio_integrity_endio(struct bio *bio)
  {
  	return true;
  }
  #endif /* CONFIG_BLK_DEV_INTEGRITY */
  
  unsigned long blk_rq_timeout(unsigned long timeout);
  void blk_add_timer(struct request *req);
  
  bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
  			     struct bio *bio);
  bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
  			    struct bio *bio);
  bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
  		struct bio *bio);
  bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
  			    struct request **same_queue_rq);
  
  void blk_account_io_start(struct request *req, bool new_io);
  void blk_account_io_completion(struct request *req, unsigned int bytes);
  void blk_account_io_done(struct request *req, u64 now);
  
  /*
   * Internal elevator interface
   */
  #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
  
  void blk_insert_flush(struct request *rq);
  
  int elevator_init_mq(struct request_queue *q);
  int elevator_switch_mq(struct request_queue *q,
  			      struct elevator_type *new_e);
  void __elevator_exit(struct request_queue *, struct elevator_queue *);
  int elv_register_queue(struct request_queue *q);
  void elv_unregister_queue(struct request_queue *q);
  
  static inline void elevator_exit(struct request_queue *q,
  		struct elevator_queue *e)
  {
  	blk_mq_sched_free_requests(q);
  	__elevator_exit(q, e);
  }
  
  struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
  
  #ifdef CONFIG_FAIL_IO_TIMEOUT
  int blk_should_fake_timeout(struct request_queue *);
  ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
  ssize_t part_timeout_store(struct device *, struct device_attribute *,
  				const char *, size_t);
  #else
  static inline int blk_should_fake_timeout(struct request_queue *q)
  {
  	return 0;
  }
  #endif
  
  int ll_back_merge_fn(struct request_queue *q, struct request *req,
  		     struct bio *bio);
  int ll_front_merge_fn(struct request_queue *q, struct request *req, 
  		      struct bio *bio);
  struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
  struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
  int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
  				struct request *next);
  void blk_recalc_rq_segments(struct request *rq);
  void blk_rq_set_mixed_merge(struct request *rq);
  bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
  enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
  
  int blk_dev_init(void);
  
  /*
   * Contribute to IO statistics IFF:
   *
   *	a) it's attached to a gendisk, and
   *	b) the queue had IO stats enabled when this request was started, and
   *	c) it's a file system request
   */
  static inline bool blk_do_io_stat(struct request *rq)
  {
  	return rq->rq_disk &&
  	       (rq->rq_flags & RQF_IO_STAT) &&
  		!blk_rq_is_passthrough(rq);
  }
  
  static inline void req_set_nomerge(struct request_queue *q, struct request *req)
  {
  	req->cmd_flags |= REQ_NOMERGE;
  	if (req == q->last_merge)
  		q->last_merge = NULL;
  }
  
  /*
   * The max size one bio can handle is UINT_MAX becasue bvec_iter.bi_size
   * is defined as 'unsigned int', meantime it has to aligned to with logical
   * block size which is the minimum accepted unit by hardware.
   */
  static inline unsigned int bio_allowed_max_sectors(struct request_queue *q)
  {
  	return round_down(UINT_MAX, queue_logical_block_size(q)) >> 9;
  }
  
  /*
   * Internal io_context interface
   */
  void get_io_context(struct io_context *ioc);
  struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
  struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
  			     gfp_t gfp_mask);
  void ioc_clear_queue(struct request_queue *q);
  
  int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
  
  /**
   * create_io_context - try to create task->io_context
   * @gfp_mask: allocation mask
   * @node: allocation node
   *
   * If %current->io_context is %NULL, allocate a new io_context and install
   * it.  Returns the current %current->io_context which may be %NULL if
   * allocation failed.
   *
   * Note that this function can't be called with IRQ disabled because
   * task_lock which protects %current->io_context is IRQ-unsafe.
   */
  static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
  {
  	WARN_ON_ONCE(irqs_disabled());
  	if (unlikely(!current->io_context))
  		create_task_io_context(current, gfp_mask, node);
  	return current->io_context;
  }
  
  /*
   * Internal throttling interface
   */
  #ifdef CONFIG_BLK_DEV_THROTTLING
  extern void blk_throtl_drain(struct request_queue *q);
  extern int blk_throtl_init(struct request_queue *q);
  extern void blk_throtl_exit(struct request_queue *q);
  extern void blk_throtl_register_queue(struct request_queue *q);
  #else /* CONFIG_BLK_DEV_THROTTLING */
  static inline void blk_throtl_drain(struct request_queue *q) { }
  static inline int blk_throtl_init(struct request_queue *q) { return 0; }
  static inline void blk_throtl_exit(struct request_queue *q) { }
  static inline void blk_throtl_register_queue(struct request_queue *q) { }
  #endif /* CONFIG_BLK_DEV_THROTTLING */
  #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
  extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
  extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
  	const char *page, size_t count);
  extern void blk_throtl_bio_endio(struct bio *bio);
  extern void blk_throtl_stat_add(struct request *rq, u64 time);
  #else
  static inline void blk_throtl_bio_endio(struct bio *bio) { }
  static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
  #endif
  
  #ifdef CONFIG_BOUNCE
  extern int init_emergency_isa_pool(void);
  extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
  #else
  static inline int init_emergency_isa_pool(void)
  {
  	return 0;
  }
  static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
  {
  }
  #endif /* CONFIG_BOUNCE */
  
  #ifdef CONFIG_BLK_CGROUP_IOLATENCY
  extern int blk_iolatency_init(struct request_queue *q);
  #else
  static inline int blk_iolatency_init(struct request_queue *q) { return 0; }
  #endif
  
  struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp);
  
  #ifdef CONFIG_BLK_DEV_ZONED
  void blk_queue_free_zone_bitmaps(struct request_queue *q);
  #else
  static inline void blk_queue_free_zone_bitmaps(struct request_queue *q) {}
  #endif
  
  #endif /* BLK_INTERNAL_H */
  