/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_ELEVATOR_H #define _LINUX_ELEVATOR_H #include <linux/percpu.h> #include <linux/hashtable.h> #ifdef CONFIG_BLOCK struct io_cq; struct elevator_type; #ifdef CONFIG_BLK_DEBUG_FS struct blk_mq_debugfs_attr; #endif /* * 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_mq_ops { int (*init_sched)(struct request_queue *, struct elevator_type *); 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 blk_mq_hw_ctx *); bool (*allow_merge)(struct request_queue *, struct request *, struct bio *); bool (*bio_merge)(struct blk_mq_hw_ctx *, 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)(unsigned int, struct blk_mq_alloc_data *); void (*prepare_request)(struct request *); void (*finish_request)(struct request *); void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool); 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 */ struct elv_fs_entry *elevator_attrs; const char *elevator_name; const char *elevator_alias; const unsigned int elevator_features; 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; }; #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; void *elevator_data; struct kobject kobj; struct mutex sysfs_lock; unsigned int registered:1; DECLARE_HASHTABLE(hash, ELV_HASH_BITS); }; /* * 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 *); 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 */ extern ssize_t elv_iosched_show(struct request_queue *, char *); extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); extern bool elv_bio_merge_ok(struct request *, struct bio *); extern struct elevator_queue *elevator_alloc(struct request_queue *, struct elevator_type *); /* * 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 rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) #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) /* * Elevator features. */ /* Supports zoned block devices sequential write constraint */ #define ELEVATOR_F_ZBD_SEQ_WRITE (1U << 0) #endif /* CONFIG_BLOCK */ #endif