1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 #include <linux/percpu.h>
10 typedef int (elevator_merge_fn
) (struct request_queue
*, struct request
**,
13 typedef void (elevator_merge_req_fn
) (struct request_queue
*, struct request
*, struct request
*);
15 typedef void (elevator_merged_fn
) (struct request_queue
*, struct request
*, int);
17 typedef int (elevator_allow_merge_fn
) (struct request_queue
*, struct request
*, struct bio
*);
19 typedef void (elevator_bio_merged_fn
) (struct request_queue
*,
20 struct request
*, struct bio
*);
22 typedef int (elevator_dispatch_fn
) (struct request_queue
*, int);
24 typedef void (elevator_add_req_fn
) (struct request_queue
*, struct request
*);
25 typedef struct request
*(elevator_request_list_fn
) (struct request_queue
*, struct request
*);
26 typedef void (elevator_completed_req_fn
) (struct request_queue
*, struct request
*);
27 typedef int (elevator_may_queue_fn
) (struct request_queue
*, int);
29 typedef void (elevator_init_icq_fn
) (struct io_cq
*);
30 typedef void (elevator_exit_icq_fn
) (struct io_cq
*);
31 typedef int (elevator_set_req_fn
) (struct request_queue
*, struct request
*,
33 typedef void (elevator_put_req_fn
) (struct request
*);
34 typedef void (elevator_activate_req_fn
) (struct request_queue
*, struct request
*);
35 typedef void (elevator_deactivate_req_fn
) (struct request_queue
*, struct request
*);
37 typedef int (elevator_init_fn
) (struct request_queue
*);
38 typedef void (elevator_exit_fn
) (struct elevator_queue
*);
42 elevator_merge_fn
*elevator_merge_fn
;
43 elevator_merged_fn
*elevator_merged_fn
;
44 elevator_merge_req_fn
*elevator_merge_req_fn
;
45 elevator_allow_merge_fn
*elevator_allow_merge_fn
;
46 elevator_bio_merged_fn
*elevator_bio_merged_fn
;
48 elevator_dispatch_fn
*elevator_dispatch_fn
;
49 elevator_add_req_fn
*elevator_add_req_fn
;
50 elevator_activate_req_fn
*elevator_activate_req_fn
;
51 elevator_deactivate_req_fn
*elevator_deactivate_req_fn
;
53 elevator_completed_req_fn
*elevator_completed_req_fn
;
55 elevator_request_list_fn
*elevator_former_req_fn
;
56 elevator_request_list_fn
*elevator_latter_req_fn
;
58 elevator_init_icq_fn
*elevator_init_icq_fn
; /* see iocontext.h */
59 elevator_exit_icq_fn
*elevator_exit_icq_fn
; /* ditto */
61 elevator_set_req_fn
*elevator_set_req_fn
;
62 elevator_put_req_fn
*elevator_put_req_fn
;
64 elevator_may_queue_fn
*elevator_may_queue_fn
;
66 elevator_init_fn
*elevator_init_fn
;
67 elevator_exit_fn
*elevator_exit_fn
;
70 #define ELV_NAME_MAX (16)
73 struct attribute attr
;
74 ssize_t (*show
)(struct elevator_queue
*, char *);
75 ssize_t (*store
)(struct elevator_queue
*, const char *, size_t);
79 * identifies an elevator type, such as AS or deadline
83 /* managed by elevator core */
84 struct kmem_cache
*icq_cache
;
86 /* fields provided by elevator implementation */
87 struct elevator_ops ops
;
88 size_t icq_size
; /* see iocontext.h */
89 size_t icq_align
; /* ditto */
90 struct elv_fs_entry
*elevator_attrs
;
91 char elevator_name
[ELV_NAME_MAX
];
92 struct module
*elevator_owner
;
94 /* managed by elevator core */
95 char icq_cache_name
[ELV_NAME_MAX
+ 5]; /* elvname + "_io_cq" */
96 struct list_head list
;
100 * each queue has an elevator_queue associated with it
102 struct elevator_queue
104 struct elevator_type
*type
;
107 struct mutex sysfs_lock
;
108 struct hlist_head
*hash
;
109 unsigned int registered
:1;
113 * block elevator interface
115 extern void elv_dispatch_sort(struct request_queue
*, struct request
*);
116 extern void elv_dispatch_add_tail(struct request_queue
*, struct request
*);
117 extern void elv_add_request(struct request_queue
*, struct request
*, int);
118 extern void __elv_add_request(struct request_queue
*, struct request
*, int);
119 extern int elv_merge(struct request_queue
*, struct request
**, struct bio
*);
120 extern void elv_merge_requests(struct request_queue
*, struct request
*,
122 extern void elv_merged_request(struct request_queue
*, struct request
*, int);
123 extern void elv_bio_merged(struct request_queue
*q
, struct request
*,
125 extern void elv_requeue_request(struct request_queue
*, struct request
*);
126 extern struct request
*elv_former_request(struct request_queue
*, struct request
*);
127 extern struct request
*elv_latter_request(struct request_queue
*, struct request
*);
128 extern int elv_register_queue(struct request_queue
*q
);
129 extern void elv_unregister_queue(struct request_queue
*q
);
130 extern int elv_may_queue(struct request_queue
*, int);
131 extern void elv_abort_queue(struct request_queue
*);
132 extern void elv_completed_request(struct request_queue
*, struct request
*);
133 extern int elv_set_request(struct request_queue
*q
, struct request
*rq
,
134 struct bio
*bio
, gfp_t gfp_mask
);
135 extern void elv_put_request(struct request_queue
*, struct request
*);
136 extern void elv_drain_elevator(struct request_queue
*);
139 * io scheduler registration
141 extern int elv_register(struct elevator_type
*);
142 extern void elv_unregister(struct elevator_type
*);
145 * io scheduler sysfs switching
147 extern ssize_t
elv_iosched_show(struct request_queue
*, char *);
148 extern ssize_t
elv_iosched_store(struct request_queue
*, const char *, size_t);
150 extern int elevator_init(struct request_queue
*, char *);
151 extern void elevator_exit(struct elevator_queue
*);
152 extern int elevator_change(struct request_queue
*, const char *);
153 extern bool elv_rq_merge_ok(struct request
*, struct bio
*);
158 extern struct request
*elv_rb_former_request(struct request_queue
*, struct request
*);
159 extern struct request
*elv_rb_latter_request(struct request_queue
*, struct request
*);
162 * rb support functions.
164 extern void elv_rb_add(struct rb_root
*, struct request
*);
165 extern void elv_rb_del(struct rb_root
*, struct request
*);
166 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
169 * Return values from elevator merger
171 #define ELEVATOR_NO_MERGE 0
172 #define ELEVATOR_FRONT_MERGE 1
173 #define ELEVATOR_BACK_MERGE 2
176 * Insertion selection
178 #define ELEVATOR_INSERT_FRONT 1
179 #define ELEVATOR_INSERT_BACK 2
180 #define ELEVATOR_INSERT_SORT 3
181 #define ELEVATOR_INSERT_REQUEUE 4
182 #define ELEVATOR_INSERT_FLUSH 5
183 #define ELEVATOR_INSERT_SORT_MERGE 6
186 * return values from elevator_may_queue_fn
194 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
195 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
198 * Hack to reuse the csd.list list_head as the fifo time holder while
199 * the request is in the io scheduler. Saves an unsigned long in rq.
201 #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
202 #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
203 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
204 #define rq_fifo_clear(rq) do { \
205 list_del_init(&(rq)->queuelist); \
206 INIT_LIST_HEAD(&(rq)->csd.list); \
209 #endif /* CONFIG_BLOCK */