1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ELEVATOR_H
#define _ELEVATOR_H
#include <linux/percpu.h>
#include <linux/hashtable.h>
struct io_cq;
struct elevator_type;
struct blk_mq_debugfs_attr;
/*
* 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 request_queue *, 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)(blk_opf_t, 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;
};
static inline bool elevator_tryget(struct elevator_type *e)
{
return try_module_get(e->elevator_owner);
}
static inline void __elevator_get(struct elevator_type *e)
{
__module_get(e->elevator_owner);
}
static inline void elevator_put(struct elevator_type *e)
{
module_put(e->elevator_owner);
}
#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 long flags;
DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
};
#define ELEVATOR_FLAG_REGISTERED 0
#define ELEVATOR_FLAG_DISABLE_WBT 1
/*
* 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 *,
struct list_head *);
extern struct request *elv_former_request(struct request_queue *, struct request *);
extern struct request *elv_latter_request(struct request_queue *, struct request *);
void elevator_init_mq(struct request_queue *q);
/*
* 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 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)
#endif /* _ELEVATOR_H */
|
