188 lines · c
1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _ELEVATOR_H3#define _ELEVATOR_H4 5#include <linux/percpu.h>6#include <linux/hashtable.h>7#include "blk-mq.h"8 9struct io_cq;10struct elevator_type;11struct blk_mq_debugfs_attr;12 13/*14 * Return values from elevator merger15 */16enum elv_merge {17 ELEVATOR_NO_MERGE = 0,18 ELEVATOR_FRONT_MERGE = 1,19 ELEVATOR_BACK_MERGE = 2,20 ELEVATOR_DISCARD_MERGE = 3,21};22 23struct blk_mq_alloc_data;24struct blk_mq_hw_ctx;25 26struct elevator_mq_ops {27 int (*init_sched)(struct request_queue *, struct elevator_type *);28 void (*exit_sched)(struct elevator_queue *);29 int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int);30 void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int);31 void (*depth_updated)(struct blk_mq_hw_ctx *);32 33 bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);34 bool (*bio_merge)(struct request_queue *, struct bio *, unsigned int);35 int (*request_merge)(struct request_queue *q, struct request **, struct bio *);36 void (*request_merged)(struct request_queue *, struct request *, enum elv_merge);37 void (*requests_merged)(struct request_queue *, struct request *, struct request *);38 void (*limit_depth)(blk_opf_t, struct blk_mq_alloc_data *);39 void (*prepare_request)(struct request *);40 void (*finish_request)(struct request *);41 void (*insert_requests)(struct blk_mq_hw_ctx *hctx, struct list_head *list,42 blk_insert_t flags);43 struct request *(*dispatch_request)(struct blk_mq_hw_ctx *);44 bool (*has_work)(struct blk_mq_hw_ctx *);45 void (*completed_request)(struct request *, u64);46 void (*requeue_request)(struct request *);47 struct request *(*former_request)(struct request_queue *, struct request *);48 struct request *(*next_request)(struct request_queue *, struct request *);49 void (*init_icq)(struct io_cq *);50 void (*exit_icq)(struct io_cq *);51};52 53#define ELV_NAME_MAX (16)54 55struct elv_fs_entry {56 struct attribute attr;57 ssize_t (*show)(struct elevator_queue *, char *);58 ssize_t (*store)(struct elevator_queue *, const char *, size_t);59};60 61/*62 * identifies an elevator type, such as AS or deadline63 */64struct elevator_type65{66 /* managed by elevator core */67 struct kmem_cache *icq_cache;68 69 /* fields provided by elevator implementation */70 struct elevator_mq_ops ops;71 72 size_t icq_size; /* see iocontext.h */73 size_t icq_align; /* ditto */74 struct elv_fs_entry *elevator_attrs;75 const char *elevator_name;76 const char *elevator_alias;77 struct module *elevator_owner;78#ifdef CONFIG_BLK_DEBUG_FS79 const struct blk_mq_debugfs_attr *queue_debugfs_attrs;80 const struct blk_mq_debugfs_attr *hctx_debugfs_attrs;81#endif82 83 /* managed by elevator core */84 char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */85 struct list_head list;86};87 88static inline bool elevator_tryget(struct elevator_type *e)89{90 return try_module_get(e->elevator_owner);91}92 93static inline void __elevator_get(struct elevator_type *e)94{95 __module_get(e->elevator_owner);96}97 98static inline void elevator_put(struct elevator_type *e)99{100 module_put(e->elevator_owner);101}102 103#define ELV_HASH_BITS 6104 105void elv_rqhash_del(struct request_queue *q, struct request *rq);106void elv_rqhash_add(struct request_queue *q, struct request *rq);107void elv_rqhash_reposition(struct request_queue *q, struct request *rq);108struct request *elv_rqhash_find(struct request_queue *q, sector_t offset);109 110/*111 * each queue has an elevator_queue associated with it112 */113struct elevator_queue114{115 struct elevator_type *type;116 void *elevator_data;117 struct kobject kobj;118 struct mutex sysfs_lock;119 unsigned long flags;120 DECLARE_HASHTABLE(hash, ELV_HASH_BITS);121};122 123#define ELEVATOR_FLAG_REGISTERED 0124#define ELEVATOR_FLAG_DISABLE_WBT 1125 126/*127 * block elevator interface128 */129extern enum elv_merge elv_merge(struct request_queue *, struct request **,130 struct bio *);131extern void elv_merge_requests(struct request_queue *, struct request *,132 struct request *);133extern void elv_merged_request(struct request_queue *, struct request *,134 enum elv_merge);135extern bool elv_attempt_insert_merge(struct request_queue *, struct request *,136 struct list_head *);137extern struct request *elv_former_request(struct request_queue *, struct request *);138extern struct request *elv_latter_request(struct request_queue *, struct request *);139void elevator_init_mq(struct request_queue *q);140 141/*142 * io scheduler registration143 */144extern int elv_register(struct elevator_type *);145extern void elv_unregister(struct elevator_type *);146 147/*148 * io scheduler sysfs switching149 */150ssize_t elv_iosched_show(struct gendisk *disk, char *page);151int elv_iosched_load_module(struct gendisk *disk, const char *page,152 size_t count);153ssize_t elv_iosched_store(struct gendisk *disk, const char *page, size_t count);154 155extern bool elv_bio_merge_ok(struct request *, struct bio *);156extern struct elevator_queue *elevator_alloc(struct request_queue *,157 struct elevator_type *);158 159/*160 * Helper functions.161 */162extern struct request *elv_rb_former_request(struct request_queue *, struct request *);163extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);164 165/*166 * rb support functions.167 */168extern void elv_rb_add(struct rb_root *, struct request *);169extern void elv_rb_del(struct rb_root *, struct request *);170extern struct request *elv_rb_find(struct rb_root *, sector_t);171 172/*173 * Insertion selection174 */175#define ELEVATOR_INSERT_FRONT 1176#define ELEVATOR_INSERT_BACK 2177#define ELEVATOR_INSERT_SORT 3178#define ELEVATOR_INSERT_REQUEUE 4179#define ELEVATOR_INSERT_FLUSH 5180#define ELEVATOR_INSERT_SORT_MERGE 6181 182#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)183 184#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)185#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)186 187#endif /* _ELEVATOR_H */188