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b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
1da177e4
LT
2#ifndef _LINUX_ELEVATOR_H
3#define _LINUX_ELEVATOR_H
4
4a893e83 5#include <linux/percpu.h>
242d98f0 6#include <linux/hashtable.h>
4a893e83 7
9361401e
DH
8#ifdef CONFIG_BLOCK
9
7e5a8794 10struct io_cq;
d50235b7 11struct elevator_type;
d332ce09
OS
12#ifdef CONFIG_BLK_DEBUG_FS
13struct blk_mq_debugfs_attr;
14#endif
7e5a8794 15
34fe7c05
CH
16/*
17 * Return values from elevator merger
18 */
19enum elv_merge {
20 ELEVATOR_NO_MERGE = 0,
21 ELEVATOR_FRONT_MERGE = 1,
22 ELEVATOR_BACK_MERGE = 2,
1e739730 23 ELEVATOR_DISCARD_MERGE = 3,
34fe7c05
CH
24};
25
26typedef enum elv_merge (elevator_merge_fn) (struct request_queue *, struct request **,
1da177e4
LT
27 struct bio *);
28
165125e1 29typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
1da177e4 30
34fe7c05 31typedef void (elevator_merged_fn) (struct request_queue *, struct request *, enum elv_merge);
1da177e4 32
72ef799b
TE
33typedef int (elevator_allow_bio_merge_fn) (struct request_queue *,
34 struct request *, struct bio *);
35
36typedef int (elevator_allow_rq_merge_fn) (struct request_queue *,
37 struct request *, struct request *);
da775265 38
812d4026
DS
39typedef void (elevator_bio_merged_fn) (struct request_queue *,
40 struct request *, struct bio *);
41
165125e1 42typedef int (elevator_dispatch_fn) (struct request_queue *, int);
1da177e4 43
165125e1 44typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
165125e1
JA
45typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
46typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
ef295ecf 47typedef int (elevator_may_queue_fn) (struct request_queue *, unsigned int);
1da177e4 48
9b84cacd 49typedef void (elevator_init_icq_fn) (struct io_cq *);
7e5a8794 50typedef void (elevator_exit_icq_fn) (struct io_cq *);
852c788f
TH
51typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
52 struct bio *, gfp_t);
bb37b94c 53typedef void (elevator_put_req_fn) (struct request *);
165125e1
JA
54typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
55typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
1da177e4 56
d50235b7
JM
57typedef int (elevator_init_fn) (struct request_queue *,
58 struct elevator_type *e);
b374d18a 59typedef void (elevator_exit_fn) (struct elevator_queue *);
0bb97947 60typedef void (elevator_registered_fn) (struct request_queue *);
1da177e4
LT
61
62struct elevator_ops
63{
64 elevator_merge_fn *elevator_merge_fn;
65 elevator_merged_fn *elevator_merged_fn;
66 elevator_merge_req_fn *elevator_merge_req_fn;
72ef799b
TE
67 elevator_allow_bio_merge_fn *elevator_allow_bio_merge_fn;
68 elevator_allow_rq_merge_fn *elevator_allow_rq_merge_fn;
812d4026 69 elevator_bio_merged_fn *elevator_bio_merged_fn;
1da177e4 70
8922e16c 71 elevator_dispatch_fn *elevator_dispatch_fn;
1da177e4 72 elevator_add_req_fn *elevator_add_req_fn;
8922e16c 73 elevator_activate_req_fn *elevator_activate_req_fn;
1da177e4
LT
74 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
75
1da177e4
LT
76 elevator_completed_req_fn *elevator_completed_req_fn;
77
78 elevator_request_list_fn *elevator_former_req_fn;
79 elevator_request_list_fn *elevator_latter_req_fn;
80
f1f8cc94
TH
81 elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
82 elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
7e5a8794 83
1da177e4
LT
84 elevator_set_req_fn *elevator_set_req_fn;
85 elevator_put_req_fn *elevator_put_req_fn;
86
87 elevator_may_queue_fn *elevator_may_queue_fn;
88
89 elevator_init_fn *elevator_init_fn;
90 elevator_exit_fn *elevator_exit_fn;
0bb97947 91 elevator_registered_fn *elevator_registered_fn;
1da177e4
LT
92};
93
bd166ef1
JA
94struct blk_mq_alloc_data;
95struct blk_mq_hw_ctx;
96
97struct elevator_mq_ops {
98 int (*init_sched)(struct request_queue *, struct elevator_type *);
99 void (*exit_sched)(struct elevator_queue *);
ee056f98
OS
100 int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int);
101 void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int);
bd166ef1
JA
102
103 bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);
104 bool (*bio_merge)(struct blk_mq_hw_ctx *, struct bio *);
105 int (*request_merge)(struct request_queue *q, struct request **, struct bio *);
34fe7c05 106 void (*request_merged)(struct request_queue *, struct request *, enum elv_merge);
bd166ef1 107 void (*requests_merged)(struct request_queue *, struct request *, struct request *);
5bbf4e5a
CH
108 void (*limit_depth)(unsigned int, struct blk_mq_alloc_data *);
109 void (*prepare_request)(struct request *, struct bio *bio);
7b9e9361 110 void (*finish_request)(struct request *);
bd166ef1 111 void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool);
c13660a0 112 struct request *(*dispatch_request)(struct blk_mq_hw_ctx *);
bd166ef1 113 bool (*has_work)(struct blk_mq_hw_ctx *);
c05f8525 114 void (*completed_request)(struct request *);
bd166ef1
JA
115 void (*started_request)(struct request *);
116 void (*requeue_request)(struct request *);
117 struct request *(*former_request)(struct request_queue *, struct request *);
118 struct request *(*next_request)(struct request_queue *, struct request *);
bd166ef1
JA
119 void (*init_icq)(struct io_cq *);
120 void (*exit_icq)(struct io_cq *);
121};
122
1da177e4
LT
123#define ELV_NAME_MAX (16)
124
e572ec7e
AV
125struct elv_fs_entry {
126 struct attribute attr;
b374d18a
JA
127 ssize_t (*show)(struct elevator_queue *, char *);
128 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
e572ec7e
AV
129};
130
1da177e4
LT
131/*
132 * identifies an elevator type, such as AS or deadline
133 */
134struct elevator_type
135{
3d3c2379
TH
136 /* managed by elevator core */
137 struct kmem_cache *icq_cache;
138
139 /* fields provided by elevator implementation */
c51ca6cf
JA
140 union {
141 struct elevator_ops sq;
bd166ef1 142 struct elevator_mq_ops mq;
c51ca6cf 143 } ops;
f1f8cc94
TH
144 size_t icq_size; /* see iocontext.h */
145 size_t icq_align; /* ditto */
e572ec7e 146 struct elv_fs_entry *elevator_attrs;
1da177e4 147 char elevator_name[ELV_NAME_MAX];
8ac0d9a8 148 const char *elevator_alias;
1da177e4 149 struct module *elevator_owner;
bd166ef1 150 bool uses_mq;
d332ce09
OS
151#ifdef CONFIG_BLK_DEBUG_FS
152 const struct blk_mq_debugfs_attr *queue_debugfs_attrs;
153 const struct blk_mq_debugfs_attr *hctx_debugfs_attrs;
154#endif
3d3c2379
TH
155
156 /* managed by elevator core */
9bd2bbc0 157 char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */
22f746e2 158 struct list_head list;
1da177e4
LT
159};
160
242d98f0
SL
161#define ELV_HASH_BITS 6
162
70b3ea05
JA
163void elv_rqhash_del(struct request_queue *q, struct request *rq);
164void elv_rqhash_add(struct request_queue *q, struct request *rq);
165void elv_rqhash_reposition(struct request_queue *q, struct request *rq);
166struct request *elv_rqhash_find(struct request_queue *q, sector_t offset);
167
1da177e4 168/*
54069588 169 * each queue has an elevator_queue associated with it
1da177e4
LT
170 */
171struct elevator_queue
172{
22f746e2 173 struct elevator_type *type;
1da177e4
LT
174 void *elevator_data;
175 struct kobject kobj;
3d1ab40f 176 struct mutex sysfs_lock;
430c62fb 177 unsigned int registered:1;
bd166ef1 178 unsigned int uses_mq:1;
242d98f0 179 DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
1da177e4
LT
180};
181
182/*
183 * block elevator interface
184 */
165125e1
JA
185extern void elv_dispatch_sort(struct request_queue *, struct request *);
186extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
7eaceacc
JA
187extern void elv_add_request(struct request_queue *, struct request *, int);
188extern void __elv_add_request(struct request_queue *, struct request *, int);
34fe7c05
CH
189extern enum elv_merge elv_merge(struct request_queue *, struct request **,
190 struct bio *);
165125e1 191extern void elv_merge_requests(struct request_queue *, struct request *,
1da177e4 192 struct request *);
34fe7c05
CH
193extern void elv_merged_request(struct request_queue *, struct request *,
194 enum elv_merge);
812d4026
DS
195extern void elv_bio_merged(struct request_queue *q, struct request *,
196 struct bio *);
bd166ef1 197extern bool elv_attempt_insert_merge(struct request_queue *, struct request *);
165125e1 198extern void elv_requeue_request(struct request_queue *, struct request *);
165125e1
JA
199extern struct request *elv_former_request(struct request_queue *, struct request *);
200extern struct request *elv_latter_request(struct request_queue *, struct request *);
201extern int elv_register_queue(struct request_queue *q);
202extern void elv_unregister_queue(struct request_queue *q);
ef295ecf 203extern int elv_may_queue(struct request_queue *, unsigned int);
165125e1 204extern void elv_completed_request(struct request_queue *, struct request *);
852c788f
TH
205extern int elv_set_request(struct request_queue *q, struct request *rq,
206 struct bio *bio, gfp_t gfp_mask);
165125e1 207extern void elv_put_request(struct request_queue *, struct request *);
26308eab 208extern void elv_drain_elevator(struct request_queue *);
1da177e4
LT
209
210/*
211 * io scheduler registration
212 */
bb813f4c 213extern void __init load_default_elevator_module(void);
e567bf71 214extern int elv_register(struct elevator_type *);
1da177e4
LT
215extern void elv_unregister(struct elevator_type *);
216
217/*
218 * io scheduler sysfs switching
219 */
165125e1
JA
220extern ssize_t elv_iosched_show(struct request_queue *, char *);
221extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
1da177e4 222
165125e1 223extern int elevator_init(struct request_queue *, char *);
54d5329d 224extern void elevator_exit(struct request_queue *, struct elevator_queue *);
72ef799b 225extern bool elv_bio_merge_ok(struct request *, struct bio *);
d50235b7
JM
226extern struct elevator_queue *elevator_alloc(struct request_queue *,
227 struct elevator_type *);
1da177e4 228
2e662b65
JA
229/*
230 * Helper functions.
231 */
165125e1
JA
232extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
233extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
2e662b65
JA
234
235/*
236 * rb support functions.
237 */
796d5116 238extern void elv_rb_add(struct rb_root *, struct request *);
2e662b65
JA
239extern void elv_rb_del(struct rb_root *, struct request *);
240extern struct request *elv_rb_find(struct rb_root *, sector_t);
241
1da177e4
LT
242/*
243 * Insertion selection
244 */
245#define ELEVATOR_INSERT_FRONT 1
246#define ELEVATOR_INSERT_BACK 2
247#define ELEVATOR_INSERT_SORT 3
797e7dbb 248#define ELEVATOR_INSERT_REQUEUE 4
ae1b1539 249#define ELEVATOR_INSERT_FLUSH 5
5e84ea3a 250#define ELEVATOR_INSERT_SORT_MERGE 6
1da177e4
LT
251
252/*
253 * return values from elevator_may_queue_fn
254 */
255enum {
256 ELV_MQUEUE_MAY,
257 ELV_MQUEUE_NO,
258 ELV_MQUEUE_MUST,
259};
260
2e46e8b2 261#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
2e662b65 262#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
1b47f531 263
1fbfdfcd 264#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
d9a74df5 265#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
1fbfdfcd 266
bb813f4c
TH
267#else /* CONFIG_BLOCK */
268
269static inline void load_default_elevator_module(void) { }
270
9361401e 271#endif /* CONFIG_BLOCK */
1da177e4 272#endif