167 lines
5.2 KiB
C
167 lines
5.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ELEVATOR_H
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#define _ELEVATOR_H
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#include <linux/percpu.h>
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#include <linux/hashtable.h>
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struct io_cq;
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struct elevator_type;
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struct blk_mq_debugfs_attr;
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/*
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* Return values from elevator merger
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*/
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enum elv_merge {
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ELEVATOR_NO_MERGE = 0,
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ELEVATOR_FRONT_MERGE = 1,
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ELEVATOR_BACK_MERGE = 2,
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ELEVATOR_DISCARD_MERGE = 3,
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};
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struct blk_mq_alloc_data;
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struct blk_mq_hw_ctx;
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struct elevator_mq_ops {
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int (*init_sched)(struct request_queue *, struct elevator_type *);
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void (*exit_sched)(struct elevator_queue *);
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int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int);
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void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int);
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void (*depth_updated)(struct blk_mq_hw_ctx *);
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bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);
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bool (*bio_merge)(struct request_queue *, struct bio *, unsigned int);
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int (*request_merge)(struct request_queue *q, struct request **, struct bio *);
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void (*request_merged)(struct request_queue *, struct request *, enum elv_merge);
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void (*requests_merged)(struct request_queue *, struct request *, struct request *);
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void (*limit_depth)(unsigned int, struct blk_mq_alloc_data *);
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void (*prepare_request)(struct request *);
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void (*finish_request)(struct request *);
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void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool);
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struct request *(*dispatch_request)(struct blk_mq_hw_ctx *);
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bool (*has_work)(struct blk_mq_hw_ctx *);
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void (*completed_request)(struct request *, u64);
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void (*requeue_request)(struct request *);
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struct request *(*former_request)(struct request_queue *, struct request *);
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struct request *(*next_request)(struct request_queue *, struct request *);
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void (*init_icq)(struct io_cq *);
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void (*exit_icq)(struct io_cq *);
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};
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#define ELV_NAME_MAX (16)
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struct elv_fs_entry {
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struct attribute attr;
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ssize_t (*show)(struct elevator_queue *, char *);
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ssize_t (*store)(struct elevator_queue *, const char *, size_t);
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};
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/*
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* identifies an elevator type, such as AS or deadline
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*/
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struct elevator_type
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{
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/* managed by elevator core */
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struct kmem_cache *icq_cache;
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/* fields provided by elevator implementation */
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struct elevator_mq_ops ops;
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size_t icq_size; /* see iocontext.h */
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size_t icq_align; /* ditto */
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struct elv_fs_entry *elevator_attrs;
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const char *elevator_name;
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const char *elevator_alias;
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const unsigned int elevator_features;
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struct module *elevator_owner;
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#ifdef CONFIG_BLK_DEBUG_FS
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const struct blk_mq_debugfs_attr *queue_debugfs_attrs;
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const struct blk_mq_debugfs_attr *hctx_debugfs_attrs;
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#endif
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/* managed by elevator core */
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char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */
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struct list_head list;
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};
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#define ELV_HASH_BITS 6
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void elv_rqhash_del(struct request_queue *q, struct request *rq);
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void elv_rqhash_add(struct request_queue *q, struct request *rq);
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void elv_rqhash_reposition(struct request_queue *q, struct request *rq);
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struct request *elv_rqhash_find(struct request_queue *q, sector_t offset);
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/*
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* each queue has an elevator_queue associated with it
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*/
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struct elevator_queue
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{
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struct elevator_type *type;
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void *elevator_data;
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struct kobject kobj;
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struct mutex sysfs_lock;
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unsigned int registered:1;
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DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
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};
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/*
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* block elevator interface
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*/
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extern enum elv_merge elv_merge(struct request_queue *, struct request **,
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struct bio *);
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extern void elv_merge_requests(struct request_queue *, struct request *,
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struct request *);
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extern void elv_merged_request(struct request_queue *, struct request *,
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enum elv_merge);
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extern bool elv_attempt_insert_merge(struct request_queue *, struct request *,
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struct list_head *);
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extern struct request *elv_former_request(struct request_queue *, struct request *);
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extern struct request *elv_latter_request(struct request_queue *, struct request *);
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void elevator_init_mq(struct request_queue *q);
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/*
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* io scheduler registration
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*/
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extern int elv_register(struct elevator_type *);
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extern void elv_unregister(struct elevator_type *);
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/*
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* io scheduler sysfs switching
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*/
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extern ssize_t elv_iosched_show(struct request_queue *, char *);
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extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
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extern bool elv_bio_merge_ok(struct request *, struct bio *);
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extern struct elevator_queue *elevator_alloc(struct request_queue *,
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struct elevator_type *);
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/*
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* Helper functions.
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*/
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extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
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extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
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/*
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* rb support functions.
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*/
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extern void elv_rb_add(struct rb_root *, struct request *);
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extern void elv_rb_del(struct rb_root *, struct request *);
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extern struct request *elv_rb_find(struct rb_root *, sector_t);
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/*
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* Insertion selection
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*/
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#define ELEVATOR_INSERT_FRONT 1
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#define ELEVATOR_INSERT_BACK 2
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#define ELEVATOR_INSERT_SORT 3
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#define ELEVATOR_INSERT_REQUEUE 4
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#define ELEVATOR_INSERT_FLUSH 5
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#define ELEVATOR_INSERT_SORT_MERGE 6
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#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
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#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
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#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
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#endif /* _ELEVATOR_H */
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