270 lines
9.1 KiB
C
270 lines
9.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_ELEVATOR_H
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#define _LINUX_ELEVATOR_H
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#include <linux/percpu.h>
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#include <linux/hashtable.h>
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#ifdef CONFIG_BLOCK
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struct io_cq;
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struct elevator_type;
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#ifdef CONFIG_BLK_DEBUG_FS
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struct blk_mq_debugfs_attr;
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#endif
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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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typedef enum elv_merge (elevator_merge_fn) (struct request_queue *, struct request **,
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struct bio *);
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typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
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typedef void (elevator_merged_fn) (struct request_queue *, struct request *, enum elv_merge);
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typedef int (elevator_allow_bio_merge_fn) (struct request_queue *,
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struct request *, struct bio *);
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typedef int (elevator_allow_rq_merge_fn) (struct request_queue *,
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struct request *, struct request *);
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typedef void (elevator_bio_merged_fn) (struct request_queue *,
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struct request *, struct bio *);
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typedef int (elevator_dispatch_fn) (struct request_queue *, int);
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typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
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typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
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typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
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typedef int (elevator_may_queue_fn) (struct request_queue *, unsigned int);
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typedef void (elevator_init_icq_fn) (struct io_cq *);
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typedef void (elevator_exit_icq_fn) (struct io_cq *);
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typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
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struct bio *, gfp_t);
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typedef void (elevator_put_req_fn) (struct request *);
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typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
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typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
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typedef int (elevator_init_fn) (struct request_queue *,
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struct elevator_type *e);
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typedef void (elevator_exit_fn) (struct elevator_queue *);
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typedef void (elevator_registered_fn) (struct request_queue *);
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struct elevator_ops
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{
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elevator_merge_fn *elevator_merge_fn;
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elevator_merged_fn *elevator_merged_fn;
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elevator_merge_req_fn *elevator_merge_req_fn;
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elevator_allow_bio_merge_fn *elevator_allow_bio_merge_fn;
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elevator_allow_rq_merge_fn *elevator_allow_rq_merge_fn;
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elevator_bio_merged_fn *elevator_bio_merged_fn;
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elevator_dispatch_fn *elevator_dispatch_fn;
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elevator_add_req_fn *elevator_add_req_fn;
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elevator_activate_req_fn *elevator_activate_req_fn;
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elevator_deactivate_req_fn *elevator_deactivate_req_fn;
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elevator_completed_req_fn *elevator_completed_req_fn;
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elevator_request_list_fn *elevator_former_req_fn;
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elevator_request_list_fn *elevator_latter_req_fn;
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elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
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elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
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elevator_set_req_fn *elevator_set_req_fn;
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elevator_put_req_fn *elevator_put_req_fn;
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elevator_may_queue_fn *elevator_may_queue_fn;
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elevator_init_fn *elevator_init_fn;
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elevator_exit_fn *elevator_exit_fn;
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elevator_registered_fn *elevator_registered_fn;
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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 blk_mq_hw_ctx *, struct bio *);
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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 *, struct bio *bio);
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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 *);
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void (*started_request)(struct request *);
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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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union {
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struct elevator_ops sq;
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struct elevator_mq_ops mq;
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} 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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char elevator_name[ELV_NAME_MAX];
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const char *elevator_alias;
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struct module *elevator_owner;
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bool uses_mq;
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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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unsigned int uses_mq: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 void elv_dispatch_sort(struct request_queue *, struct request *);
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extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
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extern void elv_add_request(struct request_queue *, struct request *, int);
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extern void __elv_add_request(struct request_queue *, struct request *, int);
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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 void elv_bio_merged(struct request_queue *q, struct request *,
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struct bio *);
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extern bool elv_attempt_insert_merge(struct request_queue *, struct request *);
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extern void elv_requeue_request(struct request_queue *, struct request *);
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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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extern int elv_may_queue(struct request_queue *, unsigned int);
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extern void elv_completed_request(struct request_queue *, struct request *);
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extern int elv_set_request(struct request_queue *q, struct request *rq,
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struct bio *bio, gfp_t gfp_mask);
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extern void elv_put_request(struct request_queue *, struct request *);
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extern void elv_drain_elevator(struct request_queue *);
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/*
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* io scheduler registration
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*/
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extern void __init load_default_elevator_module(void);
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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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/*
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* return values from elevator_may_queue_fn
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*/
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enum {
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ELV_MQUEUE_MAY,
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ELV_MQUEUE_NO,
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ELV_MQUEUE_MUST,
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};
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#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
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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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#else /* CONFIG_BLOCK */
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static inline void load_default_elevator_module(void) { }
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#endif /* CONFIG_BLOCK */
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#endif
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