| /* 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) |
| /* Supports scheduling on multiple hardware queues */ |
| #define ELEVATOR_F_MQ_AWARE (1U << 1) |
| |
| #endif /* CONFIG_BLOCK */ |
| #endif |