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1da177e4
LT
1#ifndef _LINUX_ELEVATOR_H
2#define _LINUX_ELEVATOR_H
3
4a893e83 4#include <linux/percpu.h>
242d98f0 5#include <linux/hashtable.h>
4a893e83 6
9361401e
DH
7#ifdef CONFIG_BLOCK
8
7e5a8794 9struct io_cq;
d50235b7 10struct elevator_type;
7e5a8794 11
165125e1 12typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
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13 struct bio *);
14
165125e1 15typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
1da177e4 16
165125e1 17typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int);
1da177e4 18
165125e1 19typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *);
da775265 20
812d4026
DS
21typedef void (elevator_bio_merged_fn) (struct request_queue *,
22 struct request *, struct bio *);
23
165125e1 24typedef int (elevator_dispatch_fn) (struct request_queue *, int);
1da177e4 25
165125e1 26typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
165125e1
JA
27typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
28typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
29typedef int (elevator_may_queue_fn) (struct request_queue *, int);
1da177e4 30
9b84cacd 31typedef void (elevator_init_icq_fn) (struct io_cq *);
7e5a8794 32typedef void (elevator_exit_icq_fn) (struct io_cq *);
852c788f
TH
33typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
34 struct bio *, gfp_t);
bb37b94c 35typedef void (elevator_put_req_fn) (struct request *);
165125e1
JA
36typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
37typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
1da177e4 38
d50235b7
JM
39typedef int (elevator_init_fn) (struct request_queue *,
40 struct elevator_type *e);
b374d18a 41typedef void (elevator_exit_fn) (struct elevator_queue *);
1da177e4
LT
42
43struct elevator_ops
44{
45 elevator_merge_fn *elevator_merge_fn;
46 elevator_merged_fn *elevator_merged_fn;
47 elevator_merge_req_fn *elevator_merge_req_fn;
da775265 48 elevator_allow_merge_fn *elevator_allow_merge_fn;
812d4026 49 elevator_bio_merged_fn *elevator_bio_merged_fn;
1da177e4 50
8922e16c 51 elevator_dispatch_fn *elevator_dispatch_fn;
1da177e4 52 elevator_add_req_fn *elevator_add_req_fn;
8922e16c 53 elevator_activate_req_fn *elevator_activate_req_fn;
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54 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
55
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LT
56 elevator_completed_req_fn *elevator_completed_req_fn;
57
58 elevator_request_list_fn *elevator_former_req_fn;
59 elevator_request_list_fn *elevator_latter_req_fn;
60
f1f8cc94
TH
61 elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
62 elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
7e5a8794 63
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LT
64 elevator_set_req_fn *elevator_set_req_fn;
65 elevator_put_req_fn *elevator_put_req_fn;
66
67 elevator_may_queue_fn *elevator_may_queue_fn;
68
69 elevator_init_fn *elevator_init_fn;
70 elevator_exit_fn *elevator_exit_fn;
71};
72
73#define ELV_NAME_MAX (16)
74
e572ec7e
AV
75struct elv_fs_entry {
76 struct attribute attr;
b374d18a
JA
77 ssize_t (*show)(struct elevator_queue *, char *);
78 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
e572ec7e
AV
79};
80
1da177e4
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81/*
82 * identifies an elevator type, such as AS or deadline
83 */
84struct elevator_type
85{
3d3c2379
TH
86 /* managed by elevator core */
87 struct kmem_cache *icq_cache;
88
89 /* fields provided by elevator implementation */
1da177e4 90 struct elevator_ops ops;
f1f8cc94
TH
91 size_t icq_size; /* see iocontext.h */
92 size_t icq_align; /* ditto */
e572ec7e 93 struct elv_fs_entry *elevator_attrs;
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LT
94 char elevator_name[ELV_NAME_MAX];
95 struct module *elevator_owner;
3d3c2379
TH
96
97 /* managed by elevator core */
98 char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
22f746e2 99 struct list_head list;
1da177e4
LT
100};
101
242d98f0
SL
102#define ELV_HASH_BITS 6
103
1da177e4 104/*
54069588 105 * each queue has an elevator_queue associated with it
1da177e4
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106 */
107struct elevator_queue
108{
22f746e2 109 struct elevator_type *type;
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110 void *elevator_data;
111 struct kobject kobj;
3d1ab40f 112 struct mutex sysfs_lock;
430c62fb 113 unsigned int registered:1;
242d98f0 114 DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
1da177e4
LT
115};
116
117/*
118 * block elevator interface
119 */
165125e1
JA
120extern void elv_dispatch_sort(struct request_queue *, struct request *);
121extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
7eaceacc
JA
122extern void elv_add_request(struct request_queue *, struct request *, int);
123extern void __elv_add_request(struct request_queue *, struct request *, int);
165125e1
JA
124extern int elv_merge(struct request_queue *, struct request **, struct bio *);
125extern void elv_merge_requests(struct request_queue *, struct request *,
1da177e4 126 struct request *);
165125e1 127extern void elv_merged_request(struct request_queue *, struct request *, int);
812d4026
DS
128extern void elv_bio_merged(struct request_queue *q, struct request *,
129 struct bio *);
165125e1 130extern void elv_requeue_request(struct request_queue *, struct request *);
165125e1
JA
131extern struct request *elv_former_request(struct request_queue *, struct request *);
132extern struct request *elv_latter_request(struct request_queue *, struct request *);
133extern int elv_register_queue(struct request_queue *q);
134extern void elv_unregister_queue(struct request_queue *q);
135extern int elv_may_queue(struct request_queue *, int);
136extern void elv_completed_request(struct request_queue *, struct request *);
852c788f
TH
137extern int elv_set_request(struct request_queue *q, struct request *rq,
138 struct bio *bio, gfp_t gfp_mask);
165125e1 139extern void elv_put_request(struct request_queue *, struct request *);
26308eab 140extern void elv_drain_elevator(struct request_queue *);
1da177e4
LT
141
142/*
143 * io scheduler registration
144 */
bb813f4c 145extern void __init load_default_elevator_module(void);
e567bf71 146extern int elv_register(struct elevator_type *);
1da177e4
LT
147extern void elv_unregister(struct elevator_type *);
148
149/*
150 * io scheduler sysfs switching
151 */
165125e1
JA
152extern ssize_t elv_iosched_show(struct request_queue *, char *);
153extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
1da177e4 154
165125e1 155extern int elevator_init(struct request_queue *, char *);
b374d18a 156extern void elevator_exit(struct elevator_queue *);
5dd531a0 157extern int elevator_change(struct request_queue *, const char *);
050c8ea8 158extern bool elv_rq_merge_ok(struct request *, struct bio *);
d50235b7
JM
159extern struct elevator_queue *elevator_alloc(struct request_queue *,
160 struct elevator_type *);
1da177e4 161
2e662b65
JA
162/*
163 * Helper functions.
164 */
165125e1
JA
165extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
166extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
2e662b65
JA
167
168/*
169 * rb support functions.
170 */
796d5116 171extern void elv_rb_add(struct rb_root *, struct request *);
2e662b65
JA
172extern void elv_rb_del(struct rb_root *, struct request *);
173extern struct request *elv_rb_find(struct rb_root *, sector_t);
174
1da177e4
LT
175/*
176 * Return values from elevator merger
177 */
178#define ELEVATOR_NO_MERGE 0
179#define ELEVATOR_FRONT_MERGE 1
180#define ELEVATOR_BACK_MERGE 2
181
182/*
183 * Insertion selection
184 */
185#define ELEVATOR_INSERT_FRONT 1
186#define ELEVATOR_INSERT_BACK 2
187#define ELEVATOR_INSERT_SORT 3
797e7dbb 188#define ELEVATOR_INSERT_REQUEUE 4
ae1b1539 189#define ELEVATOR_INSERT_FLUSH 5
5e84ea3a 190#define ELEVATOR_INSERT_SORT_MERGE 6
1da177e4
LT
191
192/*
193 * return values from elevator_may_queue_fn
194 */
195enum {
196 ELV_MQUEUE_MAY,
197 ELV_MQUEUE_NO,
198 ELV_MQUEUE_MUST,
199};
200
2e46e8b2 201#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
2e662b65 202#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
1b47f531 203
1fbfdfcd 204#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
d9a74df5 205#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
1fbfdfcd 206
bb813f4c
TH
207#else /* CONFIG_BLOCK */
208
209static inline void load_default_elevator_module(void) { }
210
9361401e 211#endif /* CONFIG_BLOCK */
1da177e4 212#endif