/* SPDX-License-Identifier: GPL-2.0 */#ifndef _ELEVATOR_H#define _ELEVATOR_H #include <linux/percpu.h>#include <linux/hashtable.h>#include "blk-mq.h" struct io_cq;struct elevator_type;struct blk_mq_debugfs_attr; /* * Return values from elevator merger */enum elv_merge {	ELEVATOR_NO_MERGE	= 0,	ELEVATOR_FRONT_MERGE	= 1,	ELEVATOR_BACK_MERGE	= 2,	ELEVATOR_DISCARD_MERGE	= 3,}; struct blk_mq_alloc_data;struct blk_mq_hw_ctx; struct elevator_tags {	/* num. of hardware queues for which tags are allocated */	unsigned int nr_hw_queues;	/* depth used while allocating tags */	unsigned int nr_requests;	/* shared tag is stored at index 0 */	struct blk_mq_tags *tags[];}; struct elevator_resources {	/* holds elevator data */	void *data;	/* holds elevator tags */	struct elevator_tags *et;}; /* Holding context data for changing elevator */struct elv_change_ctx {	const char *name;	bool no_uevent; 	/* for unregistering old elevator */	struct elevator_queue *old;	/* for registering new elevator */	struct elevator_queue *new;	/* store elevator type */	struct elevator_type *type;	/* store elevator resources */	struct elevator_resources res;}; struct elevator_mq_ops {	int (*init_sched)(struct request_queue *, struct elevator_queue *);	void (*exit_sched)(struct elevator_queue *);	int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int);	void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int);	void (*depth_updated)(struct request_queue *);	void *(*alloc_sched_data)(struct request_queue *);	void (*free_sched_data)(void *); 	bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);	bool (*bio_merge)(struct request_queue *, struct bio *, unsigned int);	int (*request_merge)(struct request_queue *q, struct request **, struct bio *);	void (*request_merged)(struct request_queue *, struct request *, enum elv_merge);	void (*requests_merged)(struct request_queue *, struct request *, struct request *);	void (*limit_depth)(blk_opf_t, struct blk_mq_alloc_data *);	void (*prepare_request)(struct request *);	void (*finish_request)(struct request *);	void (*insert_requests)(struct blk_mq_hw_ctx *hctx, struct list_head *list,			blk_insert_t flags);	struct request *(*dispatch_request)(struct blk_mq_hw_ctx *);	bool (*has_work)(struct blk_mq_hw_ctx *);	void (*completed_request)(struct request *, u64);	void (*requeue_request)(struct request *);	struct request *(*former_request)(struct request_queue *, struct request *);	struct request *(*next_request)(struct request_queue *, struct request *);	void (*init_icq)(struct io_cq *);	void (*exit_icq)(struct io_cq *);}; #define ELV_NAME_MAX	(16) struct elv_fs_entry {	struct attribute attr;	ssize_t (*show)(struct elevator_queue *, char *);	ssize_t (*store)(struct elevator_queue *, const char *, size_t);}; /* * identifies an elevator type, such as AS or deadline */struct elevator_type{	/* managed by elevator core */	struct kmem_cache *icq_cache; 	/* fields provided by elevator implementation */	struct elevator_mq_ops ops; 	size_t icq_size;	/* see iocontext.h */	size_t icq_align;	/* ditto */	const struct elv_fs_entry *elevator_attrs;	const char *elevator_name;	const char *elevator_alias;	struct module *elevator_owner;#ifdef CONFIG_BLK_DEBUG_FS	const struct blk_mq_debugfs_attr *queue_debugfs_attrs;	const struct blk_mq_debugfs_attr *hctx_debugfs_attrs;#endif 	/* managed by elevator core */	char icq_cache_name[ELV_NAME_MAX + 6];	/* elvname + "_io_cq" */	struct list_head list;}; static inline bool elevator_tryget(struct elevator_type *e){	return try_module_get(e->elevator_owner);} static inline void __elevator_get(struct elevator_type *e){	__module_get(e->elevator_owner);} static inline void elevator_put(struct elevator_type *e){	module_put(e->elevator_owner);} #define ELV_HASH_BITS 6 void elv_rqhash_del(struct request_queue *q, struct request *rq);void elv_rqhash_add(struct request_queue *q, struct request *rq);void elv_rqhash_reposition(struct request_queue *q, struct request *rq);struct request *elv_rqhash_find(struct request_queue *q, sector_t offset); /* * each queue has an elevator_queue associated with it */struct elevator_queue{	struct elevator_type *type;	struct elevator_tags *et;	void *elevator_data;	struct kobject kobj;	struct mutex sysfs_lock;	unsigned long flags;	DECLARE_HASHTABLE(hash, ELV_HASH_BITS);}; #define ELEVATOR_FLAG_REGISTERED	0#define ELEVATOR_FLAG_DYING		1 /* * block elevator interface */extern enum elv_merge elv_merge(struct request_queue *, struct request **,		struct bio *);extern void elv_merge_requests(struct request_queue *, struct request *,			       struct request *);extern void elv_merged_request(struct request_queue *, struct request *,		enum elv_merge);extern bool elv_attempt_insert_merge(struct request_queue *, struct request *,				     struct list_head *);extern struct request *elv_former_request(struct request_queue *, struct request *);extern struct request *elv_latter_request(struct request_queue *, struct request *); /* * io scheduler registration */extern int elv_register(struct elevator_type *);extern void elv_unregister(struct elevator_type *); /* * io scheduler sysfs switching */ssize_t elv_iosched_show(struct gendisk *disk, char *page);ssize_t elv_iosched_store(struct gendisk *disk, const char *page, size_t count); extern bool elv_bio_merge_ok(struct request *, struct bio *);struct elevator_queue *elevator_alloc(struct request_queue *,		struct elevator_type *, struct elevator_resources *); /* * Helper functions. */extern struct request *elv_rb_former_request(struct request_queue *, struct request *);extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); /* * rb support functions. */extern void elv_rb_add(struct rb_root *, struct request *);extern void elv_rb_del(struct rb_root *, struct request *);extern struct request *elv_rb_find(struct rb_root *, sector_t); /* * Insertion selection */#define ELEVATOR_INSERT_FRONT	1#define ELEVATOR_INSERT_BACK	2#define ELEVATOR_INSERT_SORT	3#define ELEVATOR_INSERT_REQUEUE	4#define ELEVATOR_INSERT_FLUSH	5#define ELEVATOR_INSERT_SORT_MERGE	6 #define rb_entry_rq(node)	rb_entry((node), struct request, rb_node) #define rq_entry_fifo(ptr)	list_entry((ptr), struct request, queuelist)#define rq_fifo_clear(rq)	list_del_init(&(rq)->queuelist) void blk_mq_sched_reg_debugfs(struct request_queue *q);void blk_mq_sched_unreg_debugfs(struct request_queue *q); #endif /* _ELEVATOR_H */