1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 #include <linux/percpu.h>
5 #include <linux/hashtable.h>
12 typedef int (elevator_merge_fn
) (struct request_queue
*, struct request
**,
15 typedef void (elevator_merge_req_fn
) (struct request_queue
*, struct request
*, struct request
*);
17 typedef void (elevator_merged_fn
) (struct request_queue
*, struct request
*, int);
19 typedef int (elevator_allow_bio_merge_fn
) (struct request_queue
*,
20 struct request
*, struct bio
*);
22 typedef int (elevator_allow_rq_merge_fn
) (struct request_queue
*,
23 struct request
*, struct request
*);
25 typedef void (elevator_bio_merged_fn
) (struct request_queue
*,
26 struct request
*, struct bio
*);
28 typedef int (elevator_dispatch_fn
) (struct request_queue
*, int);
30 typedef void (elevator_add_req_fn
) (struct request_queue
*, struct request
*);
31 typedef struct request
*(elevator_request_list_fn
) (struct request_queue
*, struct request
*);
32 typedef void (elevator_completed_req_fn
) (struct request_queue
*, struct request
*);
33 typedef int (elevator_may_queue_fn
) (struct request_queue
*, int, int);
35 typedef void (elevator_init_icq_fn
) (struct io_cq
*);
36 typedef void (elevator_exit_icq_fn
) (struct io_cq
*);
37 typedef int (elevator_set_req_fn
) (struct request_queue
*, struct request
*,
39 typedef void (elevator_put_req_fn
) (struct request
*);
40 typedef void (elevator_activate_req_fn
) (struct request_queue
*, struct request
*);
41 typedef void (elevator_deactivate_req_fn
) (struct request_queue
*, struct request
*);
43 typedef int (elevator_init_fn
) (struct request_queue
*,
44 struct elevator_type
*e
);
45 typedef void (elevator_exit_fn
) (struct elevator_queue
*);
46 typedef void (elevator_registered_fn
) (struct request_queue
*);
50 elevator_merge_fn
*elevator_merge_fn
;
51 elevator_merged_fn
*elevator_merged_fn
;
52 elevator_merge_req_fn
*elevator_merge_req_fn
;
53 elevator_allow_bio_merge_fn
*elevator_allow_bio_merge_fn
;
54 elevator_allow_rq_merge_fn
*elevator_allow_rq_merge_fn
;
55 elevator_bio_merged_fn
*elevator_bio_merged_fn
;
57 elevator_dispatch_fn
*elevator_dispatch_fn
;
58 elevator_add_req_fn
*elevator_add_req_fn
;
59 elevator_activate_req_fn
*elevator_activate_req_fn
;
60 elevator_deactivate_req_fn
*elevator_deactivate_req_fn
;
62 elevator_completed_req_fn
*elevator_completed_req_fn
;
64 elevator_request_list_fn
*elevator_former_req_fn
;
65 elevator_request_list_fn
*elevator_latter_req_fn
;
67 elevator_init_icq_fn
*elevator_init_icq_fn
; /* see iocontext.h */
68 elevator_exit_icq_fn
*elevator_exit_icq_fn
; /* ditto */
70 elevator_set_req_fn
*elevator_set_req_fn
;
71 elevator_put_req_fn
*elevator_put_req_fn
;
73 elevator_may_queue_fn
*elevator_may_queue_fn
;
75 elevator_init_fn
*elevator_init_fn
;
76 elevator_exit_fn
*elevator_exit_fn
;
77 elevator_registered_fn
*elevator_registered_fn
;
80 #define ELV_NAME_MAX (16)
83 struct attribute attr
;
84 ssize_t (*show
)(struct elevator_queue
*, char *);
85 ssize_t (*store
)(struct elevator_queue
*, const char *, size_t);
89 * identifies an elevator type, such as AS or deadline
93 /* managed by elevator core */
94 struct kmem_cache
*icq_cache
;
96 /* fields provided by elevator implementation */
97 struct elevator_ops ops
;
98 size_t icq_size
; /* see iocontext.h */
99 size_t icq_align
; /* ditto */
100 struct elv_fs_entry
*elevator_attrs
;
101 char elevator_name
[ELV_NAME_MAX
];
102 struct module
*elevator_owner
;
104 /* managed by elevator core */
105 char icq_cache_name
[ELV_NAME_MAX
+ 5]; /* elvname + "_io_cq" */
106 struct list_head list
;
109 #define ELV_HASH_BITS 6
112 * each queue has an elevator_queue associated with it
114 struct elevator_queue
116 struct elevator_type
*type
;
119 struct mutex sysfs_lock
;
120 unsigned int registered
:1;
121 DECLARE_HASHTABLE(hash
, ELV_HASH_BITS
);
125 * block elevator interface
127 extern void elv_dispatch_sort(struct request_queue
*, struct request
*);
128 extern void elv_dispatch_add_tail(struct request_queue
*, struct request
*);
129 extern void elv_add_request(struct request_queue
*, struct request
*, int);
130 extern void __elv_add_request(struct request_queue
*, struct request
*, int);
131 extern int elv_merge(struct request_queue
*, struct request
**, struct bio
*);
132 extern void elv_merge_requests(struct request_queue
*, struct request
*,
134 extern void elv_merged_request(struct request_queue
*, struct request
*, int);
135 extern void elv_bio_merged(struct request_queue
*q
, struct request
*,
137 extern void elv_requeue_request(struct request_queue
*, struct request
*);
138 extern struct request
*elv_former_request(struct request_queue
*, struct request
*);
139 extern struct request
*elv_latter_request(struct request_queue
*, struct request
*);
140 extern int elv_register_queue(struct request_queue
*q
);
141 extern void elv_unregister_queue(struct request_queue
*q
);
142 extern int elv_may_queue(struct request_queue
*, int, int);
143 extern void elv_completed_request(struct request_queue
*, struct request
*);
144 extern int elv_set_request(struct request_queue
*q
, struct request
*rq
,
145 struct bio
*bio
, gfp_t gfp_mask
);
146 extern void elv_put_request(struct request_queue
*, struct request
*);
147 extern void elv_drain_elevator(struct request_queue
*);
150 * io scheduler registration
152 extern void __init
load_default_elevator_module(void);
153 extern int elv_register(struct elevator_type
*);
154 extern void elv_unregister(struct elevator_type
*);
157 * io scheduler sysfs switching
159 extern ssize_t
elv_iosched_show(struct request_queue
*, char *);
160 extern ssize_t
elv_iosched_store(struct request_queue
*, const char *, size_t);
162 extern int elevator_init(struct request_queue
*, char *);
163 extern void elevator_exit(struct elevator_queue
*);
164 extern int elevator_change(struct request_queue
*, const char *);
165 extern bool elv_bio_merge_ok(struct request
*, struct bio
*);
166 extern struct elevator_queue
*elevator_alloc(struct request_queue
*,
167 struct elevator_type
*);
172 extern struct request
*elv_rb_former_request(struct request_queue
*, struct request
*);
173 extern struct request
*elv_rb_latter_request(struct request_queue
*, struct request
*);
176 * rb support functions.
178 extern void elv_rb_add(struct rb_root
*, struct request
*);
179 extern void elv_rb_del(struct rb_root
*, struct request
*);
180 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
183 * Return values from elevator merger
185 #define ELEVATOR_NO_MERGE 0
186 #define ELEVATOR_FRONT_MERGE 1
187 #define ELEVATOR_BACK_MERGE 2
190 * Insertion selection
192 #define ELEVATOR_INSERT_FRONT 1
193 #define ELEVATOR_INSERT_BACK 2
194 #define ELEVATOR_INSERT_SORT 3
195 #define ELEVATOR_INSERT_REQUEUE 4
196 #define ELEVATOR_INSERT_FLUSH 5
197 #define ELEVATOR_INSERT_SORT_MERGE 6
200 * return values from elevator_may_queue_fn
208 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
209 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
211 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
212 #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
214 #else /* CONFIG_BLOCK */
216 static inline void load_default_elevator_module(void) { }
218 #endif /* CONFIG_BLOCK */