1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 #include <linux/percpu.h>
5 #include <linux/hashtable.h>
13 * Return values from elevator merger
16 ELEVATOR_NO_MERGE
= 0,
17 ELEVATOR_FRONT_MERGE
= 1,
18 ELEVATOR_BACK_MERGE
= 2,
19 ELEVATOR_DISCARD_MERGE
= 3,
22 typedef enum elv_merge (elevator_merge_fn
) (struct request_queue
*, struct request
**,
25 typedef void (elevator_merge_req_fn
) (struct request_queue
*, struct request
*, struct request
*);
27 typedef void (elevator_merged_fn
) (struct request_queue
*, struct request
*, enum elv_merge
);
29 typedef int (elevator_allow_bio_merge_fn
) (struct request_queue
*,
30 struct request
*, struct bio
*);
32 typedef int (elevator_allow_rq_merge_fn
) (struct request_queue
*,
33 struct request
*, struct request
*);
35 typedef void (elevator_bio_merged_fn
) (struct request_queue
*,
36 struct request
*, struct bio
*);
38 typedef int (elevator_dispatch_fn
) (struct request_queue
*, int);
40 typedef void (elevator_add_req_fn
) (struct request_queue
*, struct request
*);
41 typedef struct request
*(elevator_request_list_fn
) (struct request_queue
*, struct request
*);
42 typedef void (elevator_completed_req_fn
) (struct request_queue
*, struct request
*);
43 typedef int (elevator_may_queue_fn
) (struct request_queue
*, unsigned int);
45 typedef void (elevator_init_icq_fn
) (struct io_cq
*);
46 typedef void (elevator_exit_icq_fn
) (struct io_cq
*);
47 typedef int (elevator_set_req_fn
) (struct request_queue
*, struct request
*,
49 typedef void (elevator_put_req_fn
) (struct request
*);
50 typedef void (elevator_activate_req_fn
) (struct request_queue
*, struct request
*);
51 typedef void (elevator_deactivate_req_fn
) (struct request_queue
*, struct request
*);
53 typedef int (elevator_init_fn
) (struct request_queue
*,
54 struct elevator_type
*e
);
55 typedef void (elevator_exit_fn
) (struct elevator_queue
*);
56 typedef void (elevator_registered_fn
) (struct request_queue
*);
60 elevator_merge_fn
*elevator_merge_fn
;
61 elevator_merged_fn
*elevator_merged_fn
;
62 elevator_merge_req_fn
*elevator_merge_req_fn
;
63 elevator_allow_bio_merge_fn
*elevator_allow_bio_merge_fn
;
64 elevator_allow_rq_merge_fn
*elevator_allow_rq_merge_fn
;
65 elevator_bio_merged_fn
*elevator_bio_merged_fn
;
67 elevator_dispatch_fn
*elevator_dispatch_fn
;
68 elevator_add_req_fn
*elevator_add_req_fn
;
69 elevator_activate_req_fn
*elevator_activate_req_fn
;
70 elevator_deactivate_req_fn
*elevator_deactivate_req_fn
;
72 elevator_completed_req_fn
*elevator_completed_req_fn
;
74 elevator_request_list_fn
*elevator_former_req_fn
;
75 elevator_request_list_fn
*elevator_latter_req_fn
;
77 elevator_init_icq_fn
*elevator_init_icq_fn
; /* see iocontext.h */
78 elevator_exit_icq_fn
*elevator_exit_icq_fn
; /* ditto */
80 elevator_set_req_fn
*elevator_set_req_fn
;
81 elevator_put_req_fn
*elevator_put_req_fn
;
83 elevator_may_queue_fn
*elevator_may_queue_fn
;
85 elevator_init_fn
*elevator_init_fn
;
86 elevator_exit_fn
*elevator_exit_fn
;
87 elevator_registered_fn
*elevator_registered_fn
;
90 struct blk_mq_alloc_data
;
93 struct elevator_mq_ops
{
94 int (*init_sched
)(struct request_queue
*, struct elevator_type
*);
95 void (*exit_sched
)(struct elevator_queue
*);
96 int (*init_hctx
)(struct blk_mq_hw_ctx
*, unsigned int);
97 void (*exit_hctx
)(struct blk_mq_hw_ctx
*, unsigned int);
99 bool (*allow_merge
)(struct request_queue
*, struct request
*, struct bio
*);
100 bool (*bio_merge
)(struct blk_mq_hw_ctx
*, struct bio
*);
101 int (*request_merge
)(struct request_queue
*q
, struct request
**, struct bio
*);
102 void (*request_merged
)(struct request_queue
*, struct request
*, enum elv_merge
);
103 void (*requests_merged
)(struct request_queue
*, struct request
*, struct request
*);
104 struct request
*(*get_request
)(struct request_queue
*, unsigned int, struct blk_mq_alloc_data
*);
105 void (*put_request
)(struct request
*);
106 void (*insert_requests
)(struct blk_mq_hw_ctx
*, struct list_head
*, bool);
107 struct request
*(*dispatch_request
)(struct blk_mq_hw_ctx
*);
108 bool (*has_work
)(struct blk_mq_hw_ctx
*);
109 void (*completed_request
)(struct request
*);
110 void (*started_request
)(struct request
*);
111 void (*requeue_request
)(struct request
*);
112 struct request
*(*former_request
)(struct request_queue
*, struct request
*);
113 struct request
*(*next_request
)(struct request_queue
*, struct request
*);
114 int (*get_rq_priv
)(struct request_queue
*, struct request
*, struct bio
*);
115 void (*put_rq_priv
)(struct request_queue
*, struct request
*);
116 void (*init_icq
)(struct io_cq
*);
117 void (*exit_icq
)(struct io_cq
*);
120 #define ELV_NAME_MAX (16)
122 struct elv_fs_entry
{
123 struct attribute attr
;
124 ssize_t (*show
)(struct elevator_queue
*, char *);
125 ssize_t (*store
)(struct elevator_queue
*, const char *, size_t);
129 * identifies an elevator type, such as AS or deadline
133 /* managed by elevator core */
134 struct kmem_cache
*icq_cache
;
136 /* fields provided by elevator implementation */
138 struct elevator_ops sq
;
139 struct elevator_mq_ops mq
;
141 size_t icq_size
; /* see iocontext.h */
142 size_t icq_align
; /* ditto */
143 struct elv_fs_entry
*elevator_attrs
;
144 char elevator_name
[ELV_NAME_MAX
];
145 struct module
*elevator_owner
;
148 /* managed by elevator core */
149 char icq_cache_name
[ELV_NAME_MAX
+ 5]; /* elvname + "_io_cq" */
150 struct list_head list
;
153 #define ELV_HASH_BITS 6
155 void elv_rqhash_del(struct request_queue
*q
, struct request
*rq
);
156 void elv_rqhash_add(struct request_queue
*q
, struct request
*rq
);
157 void elv_rqhash_reposition(struct request_queue
*q
, struct request
*rq
);
158 struct request
*elv_rqhash_find(struct request_queue
*q
, sector_t offset
);
161 * each queue has an elevator_queue associated with it
163 struct elevator_queue
165 struct elevator_type
*type
;
168 struct mutex sysfs_lock
;
169 unsigned int registered
:1;
170 unsigned int uses_mq
:1;
171 DECLARE_HASHTABLE(hash
, ELV_HASH_BITS
);
175 * block elevator interface
177 extern void elv_dispatch_sort(struct request_queue
*, struct request
*);
178 extern void elv_dispatch_add_tail(struct request_queue
*, struct request
*);
179 extern void elv_add_request(struct request_queue
*, struct request
*, int);
180 extern void __elv_add_request(struct request_queue
*, struct request
*, int);
181 extern enum elv_merge
elv_merge(struct request_queue
*, struct request
**,
183 extern void elv_merge_requests(struct request_queue
*, struct request
*,
185 extern void elv_merged_request(struct request_queue
*, struct request
*,
187 extern void elv_bio_merged(struct request_queue
*q
, struct request
*,
189 extern bool elv_attempt_insert_merge(struct request_queue
*, struct request
*);
190 extern void elv_requeue_request(struct request_queue
*, struct request
*);
191 extern struct request
*elv_former_request(struct request_queue
*, struct request
*);
192 extern struct request
*elv_latter_request(struct request_queue
*, struct request
*);
193 extern int elv_register_queue(struct request_queue
*q
);
194 extern void elv_unregister_queue(struct request_queue
*q
);
195 extern int elv_may_queue(struct request_queue
*, unsigned int);
196 extern void elv_completed_request(struct request_queue
*, struct request
*);
197 extern int elv_set_request(struct request_queue
*q
, struct request
*rq
,
198 struct bio
*bio
, gfp_t gfp_mask
);
199 extern void elv_put_request(struct request_queue
*, struct request
*);
200 extern void elv_drain_elevator(struct request_queue
*);
203 * io scheduler registration
205 extern void __init
load_default_elevator_module(void);
206 extern int elv_register(struct elevator_type
*);
207 extern void elv_unregister(struct elevator_type
*);
210 * io scheduler sysfs switching
212 extern ssize_t
elv_iosched_show(struct request_queue
*, char *);
213 extern ssize_t
elv_iosched_store(struct request_queue
*, const char *, size_t);
215 extern int elevator_init(struct request_queue
*, char *);
216 extern void elevator_exit(struct request_queue
*, struct elevator_queue
*);
217 extern int elevator_change(struct request_queue
*, const char *);
218 extern bool elv_bio_merge_ok(struct request
*, struct bio
*);
219 extern struct elevator_queue
*elevator_alloc(struct request_queue
*,
220 struct elevator_type
*);
225 extern struct request
*elv_rb_former_request(struct request_queue
*, struct request
*);
226 extern struct request
*elv_rb_latter_request(struct request_queue
*, struct request
*);
229 * rb support functions.
231 extern void elv_rb_add(struct rb_root
*, struct request
*);
232 extern void elv_rb_del(struct rb_root
*, struct request
*);
233 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
236 * Insertion selection
238 #define ELEVATOR_INSERT_FRONT 1
239 #define ELEVATOR_INSERT_BACK 2
240 #define ELEVATOR_INSERT_SORT 3
241 #define ELEVATOR_INSERT_REQUEUE 4
242 #define ELEVATOR_INSERT_FLUSH 5
243 #define ELEVATOR_INSERT_SORT_MERGE 6
246 * return values from elevator_may_queue_fn
254 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
255 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
257 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
258 #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
260 #else /* CONFIG_BLOCK */
262 static inline void load_default_elevator_module(void) { }
264 #endif /* CONFIG_BLOCK */