1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 #include <linux/percpu.h>
5 #include <linux/hashtable.h>
11 #ifdef CONFIG_BLK_DEBUG_FS
12 struct blk_mq_debugfs_attr
;
16 * Return values from elevator merger
19 ELEVATOR_NO_MERGE
= 0,
20 ELEVATOR_FRONT_MERGE
= 1,
21 ELEVATOR_BACK_MERGE
= 2,
22 ELEVATOR_DISCARD_MERGE
= 3,
25 typedef enum elv_merge (elevator_merge_fn
) (struct request_queue
*, struct request
**,
28 typedef void (elevator_merge_req_fn
) (struct request_queue
*, struct request
*, struct request
*);
30 typedef void (elevator_merged_fn
) (struct request_queue
*, struct request
*, enum elv_merge
);
32 typedef int (elevator_allow_bio_merge_fn
) (struct request_queue
*,
33 struct request
*, struct bio
*);
35 typedef int (elevator_allow_rq_merge_fn
) (struct request_queue
*,
36 struct request
*, struct request
*);
38 typedef void (elevator_bio_merged_fn
) (struct request_queue
*,
39 struct request
*, struct bio
*);
41 typedef int (elevator_dispatch_fn
) (struct request_queue
*, int);
43 typedef void (elevator_add_req_fn
) (struct request_queue
*, struct request
*);
44 typedef struct request
*(elevator_request_list_fn
) (struct request_queue
*, struct request
*);
45 typedef void (elevator_completed_req_fn
) (struct request_queue
*, struct request
*);
46 typedef int (elevator_may_queue_fn
) (struct request_queue
*, unsigned int);
48 typedef void (elevator_init_icq_fn
) (struct io_cq
*);
49 typedef void (elevator_exit_icq_fn
) (struct io_cq
*);
50 typedef int (elevator_set_req_fn
) (struct request_queue
*, struct request
*,
52 typedef void (elevator_put_req_fn
) (struct request
*);
53 typedef void (elevator_activate_req_fn
) (struct request_queue
*, struct request
*);
54 typedef void (elevator_deactivate_req_fn
) (struct request_queue
*, struct request
*);
56 typedef int (elevator_init_fn
) (struct request_queue
*,
57 struct elevator_type
*e
);
58 typedef void (elevator_exit_fn
) (struct elevator_queue
*);
59 typedef void (elevator_registered_fn
) (struct request_queue
*);
63 elevator_merge_fn
*elevator_merge_fn
;
64 elevator_merged_fn
*elevator_merged_fn
;
65 elevator_merge_req_fn
*elevator_merge_req_fn
;
66 elevator_allow_bio_merge_fn
*elevator_allow_bio_merge_fn
;
67 elevator_allow_rq_merge_fn
*elevator_allow_rq_merge_fn
;
68 elevator_bio_merged_fn
*elevator_bio_merged_fn
;
70 elevator_dispatch_fn
*elevator_dispatch_fn
;
71 elevator_add_req_fn
*elevator_add_req_fn
;
72 elevator_activate_req_fn
*elevator_activate_req_fn
;
73 elevator_deactivate_req_fn
*elevator_deactivate_req_fn
;
75 elevator_completed_req_fn
*elevator_completed_req_fn
;
77 elevator_request_list_fn
*elevator_former_req_fn
;
78 elevator_request_list_fn
*elevator_latter_req_fn
;
80 elevator_init_icq_fn
*elevator_init_icq_fn
; /* see iocontext.h */
81 elevator_exit_icq_fn
*elevator_exit_icq_fn
; /* ditto */
83 elevator_set_req_fn
*elevator_set_req_fn
;
84 elevator_put_req_fn
*elevator_put_req_fn
;
86 elevator_may_queue_fn
*elevator_may_queue_fn
;
88 elevator_init_fn
*elevator_init_fn
;
89 elevator_exit_fn
*elevator_exit_fn
;
90 elevator_registered_fn
*elevator_registered_fn
;
93 struct blk_mq_alloc_data
;
96 struct elevator_mq_ops
{
97 int (*init_sched
)(struct request_queue
*, struct elevator_type
*);
98 void (*exit_sched
)(struct elevator_queue
*);
99 int (*init_hctx
)(struct blk_mq_hw_ctx
*, unsigned int);
100 void (*exit_hctx
)(struct blk_mq_hw_ctx
*, unsigned int);
102 bool (*allow_merge
)(struct request_queue
*, struct request
*, struct bio
*);
103 bool (*bio_merge
)(struct blk_mq_hw_ctx
*, struct bio
*);
104 int (*request_merge
)(struct request_queue
*q
, struct request
**, struct bio
*);
105 void (*request_merged
)(struct request_queue
*, struct request
*, enum elv_merge
);
106 void (*requests_merged
)(struct request_queue
*, struct request
*, struct request
*);
107 void (*limit_depth
)(unsigned int, struct blk_mq_alloc_data
*);
108 void (*prepare_request
)(struct request
*, struct bio
*bio
);
109 void (*finish_request
)(struct request
*);
110 void (*insert_requests
)(struct blk_mq_hw_ctx
*, struct list_head
*, bool);
111 struct request
*(*dispatch_request
)(struct blk_mq_hw_ctx
*);
112 bool (*has_work
)(struct blk_mq_hw_ctx
*);
113 void (*completed_request
)(struct request
*);
114 void (*started_request
)(struct request
*);
115 void (*requeue_request
)(struct request
*);
116 struct request
*(*former_request
)(struct request_queue
*, struct request
*);
117 struct request
*(*next_request
)(struct request_queue
*, struct request
*);
118 void (*init_icq
)(struct io_cq
*);
119 void (*exit_icq
)(struct io_cq
*);
122 #define ELV_NAME_MAX (16)
124 struct elv_fs_entry
{
125 struct attribute attr
;
126 ssize_t (*show
)(struct elevator_queue
*, char *);
127 ssize_t (*store
)(struct elevator_queue
*, const char *, size_t);
131 * identifies an elevator type, such as AS or deadline
135 /* managed by elevator core */
136 struct kmem_cache
*icq_cache
;
138 /* fields provided by elevator implementation */
140 struct elevator_ops sq
;
141 struct elevator_mq_ops mq
;
143 size_t icq_size
; /* see iocontext.h */
144 size_t icq_align
; /* ditto */
145 struct elv_fs_entry
*elevator_attrs
;
146 char elevator_name
[ELV_NAME_MAX
];
147 struct module
*elevator_owner
;
149 #ifdef CONFIG_BLK_DEBUG_FS
150 const struct blk_mq_debugfs_attr
*queue_debugfs_attrs
;
151 const struct blk_mq_debugfs_attr
*hctx_debugfs_attrs
;
154 /* managed by elevator core */
155 char icq_cache_name
[ELV_NAME_MAX
+ 6]; /* elvname + "_io_cq" */
156 struct list_head list
;
159 #define ELV_HASH_BITS 6
161 void elv_rqhash_del(struct request_queue
*q
, struct request
*rq
);
162 void elv_rqhash_add(struct request_queue
*q
, struct request
*rq
);
163 void elv_rqhash_reposition(struct request_queue
*q
, struct request
*rq
);
164 struct request
*elv_rqhash_find(struct request_queue
*q
, sector_t offset
);
167 * each queue has an elevator_queue associated with it
169 struct elevator_queue
171 struct elevator_type
*type
;
174 struct mutex sysfs_lock
;
175 unsigned int registered
:1;
176 unsigned int uses_mq
:1;
177 DECLARE_HASHTABLE(hash
, ELV_HASH_BITS
);
181 * block elevator interface
183 extern void elv_dispatch_sort(struct request_queue
*, struct request
*);
184 extern void elv_dispatch_add_tail(struct request_queue
*, struct request
*);
185 extern void elv_add_request(struct request_queue
*, struct request
*, int);
186 extern void __elv_add_request(struct request_queue
*, struct request
*, int);
187 extern enum elv_merge
elv_merge(struct request_queue
*, struct request
**,
189 extern void elv_merge_requests(struct request_queue
*, struct request
*,
191 extern void elv_merged_request(struct request_queue
*, struct request
*,
193 extern void elv_bio_merged(struct request_queue
*q
, struct request
*,
195 extern bool elv_attempt_insert_merge(struct request_queue
*, struct request
*);
196 extern void elv_requeue_request(struct request_queue
*, struct request
*);
197 extern struct request
*elv_former_request(struct request_queue
*, struct request
*);
198 extern struct request
*elv_latter_request(struct request_queue
*, struct request
*);
199 extern int elv_register_queue(struct request_queue
*q
);
200 extern void elv_unregister_queue(struct request_queue
*q
);
201 extern int elv_may_queue(struct request_queue
*, unsigned int);
202 extern void elv_completed_request(struct request_queue
*, struct request
*);
203 extern int elv_set_request(struct request_queue
*q
, struct request
*rq
,
204 struct bio
*bio
, gfp_t gfp_mask
);
205 extern void elv_put_request(struct request_queue
*, struct request
*);
206 extern void elv_drain_elevator(struct request_queue
*);
209 * io scheduler registration
211 extern void __init
load_default_elevator_module(void);
212 extern int elv_register(struct elevator_type
*);
213 extern void elv_unregister(struct elevator_type
*);
216 * io scheduler sysfs switching
218 extern ssize_t
elv_iosched_show(struct request_queue
*, char *);
219 extern ssize_t
elv_iosched_store(struct request_queue
*, const char *, size_t);
221 extern int elevator_init(struct request_queue
*, char *);
222 extern void elevator_exit(struct request_queue
*, struct elevator_queue
*);
223 extern bool elv_bio_merge_ok(struct request
*, struct bio
*);
224 extern struct elevator_queue
*elevator_alloc(struct request_queue
*,
225 struct elevator_type
*);
230 extern struct request
*elv_rb_former_request(struct request_queue
*, struct request
*);
231 extern struct request
*elv_rb_latter_request(struct request_queue
*, struct request
*);
234 * rb support functions.
236 extern void elv_rb_add(struct rb_root
*, struct request
*);
237 extern void elv_rb_del(struct rb_root
*, struct request
*);
238 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
241 * Insertion selection
243 #define ELEVATOR_INSERT_FRONT 1
244 #define ELEVATOR_INSERT_BACK 2
245 #define ELEVATOR_INSERT_SORT 3
246 #define ELEVATOR_INSERT_REQUEUE 4
247 #define ELEVATOR_INSERT_FLUSH 5
248 #define ELEVATOR_INSERT_SORT_MERGE 6
251 * return values from elevator_may_queue_fn
259 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
260 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
262 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
263 #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
265 #else /* CONFIG_BLOCK */
267 static inline void load_default_elevator_module(void) { }
269 #endif /* CONFIG_BLOCK */