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
*, gfp_t
);
32 typedef void (elevator_put_req_fn
) (struct request
*);
33 typedef void (elevator_activate_req_fn
) (struct request_queue
*, struct request
*);
34 typedef void (elevator_deactivate_req_fn
) (struct request_queue
*, struct request
*);
36 typedef void *(elevator_init_fn
) (struct request_queue
*);
37 typedef void (elevator_exit_fn
) (struct elevator_queue
*);
41 elevator_merge_fn
*elevator_merge_fn
;
42 elevator_merged_fn
*elevator_merged_fn
;
43 elevator_merge_req_fn
*elevator_merge_req_fn
;
44 elevator_allow_merge_fn
*elevator_allow_merge_fn
;
47 * Used for both plugged list and elevator merging and in the
48 * former case called without queue_lock. Read comment on top of
49 * attempt_plug_merge() for details.
51 elevator_bio_merged_fn
*elevator_bio_merged_fn
;
53 elevator_dispatch_fn
*elevator_dispatch_fn
;
54 elevator_add_req_fn
*elevator_add_req_fn
;
55 elevator_activate_req_fn
*elevator_activate_req_fn
;
56 elevator_deactivate_req_fn
*elevator_deactivate_req_fn
;
58 elevator_completed_req_fn
*elevator_completed_req_fn
;
60 elevator_request_list_fn
*elevator_former_req_fn
;
61 elevator_request_list_fn
*elevator_latter_req_fn
;
63 elevator_init_icq_fn
*elevator_init_icq_fn
; /* see iocontext.h */
64 elevator_exit_icq_fn
*elevator_exit_icq_fn
; /* ditto */
66 elevator_set_req_fn
*elevator_set_req_fn
;
67 elevator_put_req_fn
*elevator_put_req_fn
;
69 elevator_may_queue_fn
*elevator_may_queue_fn
;
71 elevator_init_fn
*elevator_init_fn
;
72 elevator_exit_fn
*elevator_exit_fn
;
75 #define ELV_NAME_MAX (16)
78 struct attribute attr
;
79 ssize_t (*show
)(struct elevator_queue
*, char *);
80 ssize_t (*store
)(struct elevator_queue
*, const char *, size_t);
84 * identifies an elevator type, such as AS or deadline
88 /* managed by elevator core */
89 struct kmem_cache
*icq_cache
;
91 /* fields provided by elevator implementation */
92 struct elevator_ops ops
;
93 size_t icq_size
; /* see iocontext.h */
94 size_t icq_align
; /* ditto */
95 struct elv_fs_entry
*elevator_attrs
;
96 char elevator_name
[ELV_NAME_MAX
];
97 struct module
*elevator_owner
;
99 /* managed by elevator core */
100 char icq_cache_name
[ELV_NAME_MAX
+ 5]; /* elvname + "_io_cq" */
101 struct list_head list
;
105 * each queue has an elevator_queue associated with it
107 struct elevator_queue
109 struct elevator_type
*type
;
112 struct mutex sysfs_lock
;
113 struct hlist_head
*hash
;
114 unsigned int registered
:1;
118 * block elevator interface
120 extern void elv_dispatch_sort(struct request_queue
*, struct request
*);
121 extern void elv_dispatch_add_tail(struct request_queue
*, struct request
*);
122 extern void elv_add_request(struct request_queue
*, struct request
*, int);
123 extern void __elv_add_request(struct request_queue
*, struct request
*, int);
124 extern int elv_merge(struct request_queue
*, struct request
**, struct bio
*);
125 extern int elv_try_merge(struct request
*, struct bio
*);
126 extern void elv_merge_requests(struct request_queue
*, struct request
*,
128 extern void elv_merged_request(struct request_queue
*, struct request
*, int);
129 extern void elv_bio_merged(struct request_queue
*q
, struct request
*,
131 extern void elv_requeue_request(struct request_queue
*, struct request
*);
132 extern struct request
*elv_former_request(struct request_queue
*, struct request
*);
133 extern struct request
*elv_latter_request(struct request_queue
*, struct request
*);
134 extern int elv_register_queue(struct request_queue
*q
);
135 extern void elv_unregister_queue(struct request_queue
*q
);
136 extern int elv_may_queue(struct request_queue
*, int);
137 extern void elv_abort_queue(struct request_queue
*);
138 extern void elv_completed_request(struct request_queue
*, struct request
*);
139 extern int elv_set_request(struct request_queue
*, struct request
*, gfp_t
);
140 extern void elv_put_request(struct request_queue
*, struct request
*);
141 extern void elv_drain_elevator(struct request_queue
*);
144 * io scheduler registration
146 extern int elv_register(struct elevator_type
*);
147 extern void elv_unregister(struct elevator_type
*);
150 * io scheduler sysfs switching
152 extern ssize_t
elv_iosched_show(struct request_queue
*, char *);
153 extern ssize_t
elv_iosched_store(struct request_queue
*, const char *, size_t);
155 extern int elevator_init(struct request_queue
*, char *);
156 extern void elevator_exit(struct elevator_queue
*);
157 extern int elevator_change(struct request_queue
*, const char *);
158 extern int elv_rq_merge_ok(struct request
*, struct bio
*);
163 extern struct request
*elv_rb_former_request(struct request_queue
*, struct request
*);
164 extern struct request
*elv_rb_latter_request(struct request_queue
*, struct request
*);
167 * rb support functions.
169 extern void elv_rb_add(struct rb_root
*, struct request
*);
170 extern void elv_rb_del(struct rb_root
*, struct request
*);
171 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
174 * Return values from elevator merger
176 #define ELEVATOR_NO_MERGE 0
177 #define ELEVATOR_FRONT_MERGE 1
178 #define ELEVATOR_BACK_MERGE 2
181 * Insertion selection
183 #define ELEVATOR_INSERT_FRONT 1
184 #define ELEVATOR_INSERT_BACK 2
185 #define ELEVATOR_INSERT_SORT 3
186 #define ELEVATOR_INSERT_REQUEUE 4
187 #define ELEVATOR_INSERT_FLUSH 5
188 #define ELEVATOR_INSERT_SORT_MERGE 6
191 * return values from elevator_may_queue_fn
199 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
200 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
203 * Hack to reuse the csd.list list_head as the fifo time holder while
204 * the request is in the io scheduler. Saves an unsigned long in rq.
206 #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
207 #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
208 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
209 #define rq_fifo_clear(rq) do { \
210 list_del_init(&(rq)->queuelist); \
211 INIT_LIST_HEAD(&(rq)->csd.list); \
214 #endif /* CONFIG_BLOCK */