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 struct request
*(*get_request
)(struct request_queue
*, unsigned int, struct blk_mq_alloc_data
*);
108 void (*put_request
)(struct request
*);
109 void (*insert_requests
)(struct blk_mq_hw_ctx
*, struct list_head
*, bool);
110 struct request
*(*dispatch_request
)(struct blk_mq_hw_ctx
*);
111 bool (*has_work
)(struct blk_mq_hw_ctx
*);
112 void (*completed_request
)(struct request
*);
113 void (*started_request
)(struct request
*);
114 void (*requeue_request
)(struct request
*);
115 struct request
*(*former_request
)(struct request_queue
*, struct request
*);
116 struct request
*(*next_request
)(struct request_queue
*, struct request
*);
117 int (*get_rq_priv
)(struct request_queue
*, struct request
*, struct bio
*);
118 void (*put_rq_priv
)(struct request_queue
*, struct request
*);
119 void (*init_icq
)(struct io_cq
*);
120 void (*exit_icq
)(struct io_cq
*);
123 #define ELV_NAME_MAX (16)
125 struct elv_fs_entry
{
126 struct attribute attr
;
127 ssize_t (*show
)(struct elevator_queue
*, char *);
128 ssize_t (*store
)(struct elevator_queue
*, const char *, size_t);
132 * identifies an elevator type, such as AS or deadline
136 /* managed by elevator core */
137 struct kmem_cache
*icq_cache
;
139 /* fields provided by elevator implementation */
141 struct elevator_ops sq
;
142 struct elevator_mq_ops mq
;
144 size_t icq_size
; /* see iocontext.h */
145 size_t icq_align
; /* ditto */
146 struct elv_fs_entry
*elevator_attrs
;
147 char elevator_name
[ELV_NAME_MAX
];
148 struct module
*elevator_owner
;
150 #ifdef CONFIG_BLK_DEBUG_FS
151 const struct blk_mq_debugfs_attr
*queue_debugfs_attrs
;
152 const struct blk_mq_debugfs_attr
*hctx_debugfs_attrs
;
155 /* managed by elevator core */
156 char icq_cache_name
[ELV_NAME_MAX
+ 5]; /* elvname + "_io_cq" */
157 struct list_head list
;
160 #define ELV_HASH_BITS 6
162 void elv_rqhash_del(struct request_queue
*q
, struct request
*rq
);
163 void elv_rqhash_add(struct request_queue
*q
, struct request
*rq
);
164 void elv_rqhash_reposition(struct request_queue
*q
, struct request
*rq
);
165 struct request
*elv_rqhash_find(struct request_queue
*q
, sector_t offset
);
168 * each queue has an elevator_queue associated with it
170 struct elevator_queue
172 struct elevator_type
*type
;
175 struct mutex sysfs_lock
;
176 unsigned int registered
:1;
177 unsigned int uses_mq
:1;
178 DECLARE_HASHTABLE(hash
, ELV_HASH_BITS
);
182 * block elevator interface
184 extern void elv_dispatch_sort(struct request_queue
*, struct request
*);
185 extern void elv_dispatch_add_tail(struct request_queue
*, struct request
*);
186 extern void elv_add_request(struct request_queue
*, struct request
*, int);
187 extern void __elv_add_request(struct request_queue
*, struct request
*, int);
188 extern enum elv_merge
elv_merge(struct request_queue
*, struct request
**,
190 extern void elv_merge_requests(struct request_queue
*, struct request
*,
192 extern void elv_merged_request(struct request_queue
*, struct request
*,
194 extern void elv_bio_merged(struct request_queue
*q
, struct request
*,
196 extern bool elv_attempt_insert_merge(struct request_queue
*, struct request
*);
197 extern void elv_requeue_request(struct request_queue
*, struct request
*);
198 extern struct request
*elv_former_request(struct request_queue
*, struct request
*);
199 extern struct request
*elv_latter_request(struct request_queue
*, struct request
*);
200 extern int elv_register_queue(struct request_queue
*q
);
201 extern void elv_unregister_queue(struct request_queue
*q
);
202 extern int elv_may_queue(struct request_queue
*, unsigned int);
203 extern void elv_completed_request(struct request_queue
*, struct request
*);
204 extern int elv_set_request(struct request_queue
*q
, struct request
*rq
,
205 struct bio
*bio
, gfp_t gfp_mask
);
206 extern void elv_put_request(struct request_queue
*, struct request
*);
207 extern void elv_drain_elevator(struct request_queue
*);
210 * io scheduler registration
212 extern void __init
load_default_elevator_module(void);
213 extern int elv_register(struct elevator_type
*);
214 extern void elv_unregister(struct elevator_type
*);
217 * io scheduler sysfs switching
219 extern ssize_t
elv_iosched_show(struct request_queue
*, char *);
220 extern ssize_t
elv_iosched_store(struct request_queue
*, const char *, size_t);
222 extern int elevator_init(struct request_queue
*, char *);
223 extern void elevator_exit(struct request_queue
*, struct elevator_queue
*);
224 extern bool elv_bio_merge_ok(struct request
*, struct bio
*);
225 extern struct elevator_queue
*elevator_alloc(struct request_queue
*,
226 struct elevator_type
*);
231 extern struct request
*elv_rb_former_request(struct request_queue
*, struct request
*);
232 extern struct request
*elv_rb_latter_request(struct request_queue
*, struct request
*);
235 * rb support functions.
237 extern void elv_rb_add(struct rb_root
*, struct request
*);
238 extern void elv_rb_del(struct rb_root
*, struct request
*);
239 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
242 * Insertion selection
244 #define ELEVATOR_INSERT_FRONT 1
245 #define ELEVATOR_INSERT_BACK 2
246 #define ELEVATOR_INSERT_SORT 3
247 #define ELEVATOR_INSERT_REQUEUE 4
248 #define ELEVATOR_INSERT_FLUSH 5
249 #define ELEVATOR_INSERT_SORT_MERGE 6
252 * return values from elevator_may_queue_fn
260 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
261 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
263 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
264 #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
266 #else /* CONFIG_BLOCK */
268 static inline void load_default_elevator_module(void) { }
270 #endif /* CONFIG_BLOCK */