1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 #include <linux/percpu.h>
5 #include <linux/hashtable.h>
11 typedef int (elevator_merge_fn
) (struct request_queue
*, struct request
**,
14 typedef void (elevator_merge_req_fn
) (struct request_queue
*, struct request
*, struct request
*);
16 typedef void (elevator_merged_fn
) (struct request_queue
*, struct request
*, int);
18 typedef int (elevator_allow_merge_fn
) (struct request_queue
*, struct request
*, struct bio
*);
20 typedef void (elevator_bio_merged_fn
) (struct request_queue
*,
21 struct request
*, struct bio
*);
23 typedef int (elevator_dispatch_fn
) (struct request_queue
*, int);
25 typedef void (elevator_add_req_fn
) (struct request_queue
*, struct request
*);
26 typedef struct request
*(elevator_request_list_fn
) (struct request_queue
*, struct request
*);
27 typedef void (elevator_completed_req_fn
) (struct request_queue
*, struct request
*);
28 typedef int (elevator_may_queue_fn
) (struct request_queue
*, int);
30 typedef void (elevator_init_icq_fn
) (struct io_cq
*);
31 typedef void (elevator_exit_icq_fn
) (struct io_cq
*);
32 typedef int (elevator_set_req_fn
) (struct request_queue
*, struct request
*,
34 typedef void (elevator_put_req_fn
) (struct request
*);
35 typedef void (elevator_activate_req_fn
) (struct request_queue
*, struct request
*);
36 typedef void (elevator_deactivate_req_fn
) (struct request_queue
*, struct request
*);
38 typedef int (elevator_init_fn
) (struct request_queue
*);
39 typedef void (elevator_exit_fn
) (struct elevator_queue
*);
43 elevator_merge_fn
*elevator_merge_fn
;
44 elevator_merged_fn
*elevator_merged_fn
;
45 elevator_merge_req_fn
*elevator_merge_req_fn
;
46 elevator_allow_merge_fn
*elevator_allow_merge_fn
;
47 elevator_bio_merged_fn
*elevator_bio_merged_fn
;
49 elevator_dispatch_fn
*elevator_dispatch_fn
;
50 elevator_add_req_fn
*elevator_add_req_fn
;
51 elevator_activate_req_fn
*elevator_activate_req_fn
;
52 elevator_deactivate_req_fn
*elevator_deactivate_req_fn
;
54 elevator_completed_req_fn
*elevator_completed_req_fn
;
56 elevator_request_list_fn
*elevator_former_req_fn
;
57 elevator_request_list_fn
*elevator_latter_req_fn
;
59 elevator_init_icq_fn
*elevator_init_icq_fn
; /* see iocontext.h */
60 elevator_exit_icq_fn
*elevator_exit_icq_fn
; /* ditto */
62 elevator_set_req_fn
*elevator_set_req_fn
;
63 elevator_put_req_fn
*elevator_put_req_fn
;
65 elevator_may_queue_fn
*elevator_may_queue_fn
;
67 elevator_init_fn
*elevator_init_fn
;
68 elevator_exit_fn
*elevator_exit_fn
;
71 #define ELV_NAME_MAX (16)
74 struct attribute attr
;
75 ssize_t (*show
)(struct elevator_queue
*, char *);
76 ssize_t (*store
)(struct elevator_queue
*, const char *, size_t);
80 * identifies an elevator type, such as AS or deadline
84 /* managed by elevator core */
85 struct kmem_cache
*icq_cache
;
87 /* fields provided by elevator implementation */
88 struct elevator_ops ops
;
89 size_t icq_size
; /* see iocontext.h */
90 size_t icq_align
; /* ditto */
91 struct elv_fs_entry
*elevator_attrs
;
92 char elevator_name
[ELV_NAME_MAX
];
93 struct module
*elevator_owner
;
95 /* managed by elevator core */
96 char icq_cache_name
[ELV_NAME_MAX
+ 5]; /* elvname + "_io_cq" */
97 struct list_head list
;
100 #define ELV_HASH_BITS 6
103 * each queue has an elevator_queue associated with it
105 struct elevator_queue
107 struct elevator_type
*type
;
110 struct mutex sysfs_lock
;
111 unsigned int registered
:1;
112 DECLARE_HASHTABLE(hash
, ELV_HASH_BITS
);
116 * block elevator interface
118 extern void elv_dispatch_sort(struct request_queue
*, struct request
*);
119 extern void elv_dispatch_add_tail(struct request_queue
*, struct request
*);
120 extern void elv_add_request(struct request_queue
*, struct request
*, int);
121 extern void __elv_add_request(struct request_queue
*, struct request
*, int);
122 extern int elv_merge(struct request_queue
*, struct request
**, struct bio
*);
123 extern void elv_merge_requests(struct request_queue
*, struct request
*,
125 extern void elv_merged_request(struct request_queue
*, struct request
*, int);
126 extern void elv_bio_merged(struct request_queue
*q
, struct request
*,
128 extern void elv_requeue_request(struct request_queue
*, struct request
*);
129 extern struct request
*elv_former_request(struct request_queue
*, struct request
*);
130 extern struct request
*elv_latter_request(struct request_queue
*, struct request
*);
131 extern int elv_register_queue(struct request_queue
*q
);
132 extern void elv_unregister_queue(struct request_queue
*q
);
133 extern int elv_may_queue(struct request_queue
*, int);
134 extern void elv_abort_queue(struct request_queue
*);
135 extern void elv_completed_request(struct request_queue
*, struct request
*);
136 extern int elv_set_request(struct request_queue
*q
, struct request
*rq
,
137 struct bio
*bio
, gfp_t gfp_mask
);
138 extern void elv_put_request(struct request_queue
*, struct request
*);
139 extern void elv_drain_elevator(struct request_queue
*);
142 * io scheduler registration
144 extern void __init
load_default_elevator_module(void);
145 extern int elv_register(struct elevator_type
*);
146 extern void elv_unregister(struct elevator_type
*);
149 * io scheduler sysfs switching
151 extern ssize_t
elv_iosched_show(struct request_queue
*, char *);
152 extern ssize_t
elv_iosched_store(struct request_queue
*, const char *, size_t);
154 extern int elevator_init(struct request_queue
*, char *);
155 extern void elevator_exit(struct elevator_queue
*);
156 extern int elevator_change(struct request_queue
*, const char *);
157 extern bool elv_rq_merge_ok(struct request
*, struct bio
*);
162 extern struct request
*elv_rb_former_request(struct request_queue
*, struct request
*);
163 extern struct request
*elv_rb_latter_request(struct request_queue
*, struct request
*);
166 * rb support functions.
168 extern void elv_rb_add(struct rb_root
*, struct request
*);
169 extern void elv_rb_del(struct rb_root
*, struct request
*);
170 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
173 * Return values from elevator merger
175 #define ELEVATOR_NO_MERGE 0
176 #define ELEVATOR_FRONT_MERGE 1
177 #define ELEVATOR_BACK_MERGE 2
180 * Insertion selection
182 #define ELEVATOR_INSERT_FRONT 1
183 #define ELEVATOR_INSERT_BACK 2
184 #define ELEVATOR_INSERT_SORT 3
185 #define ELEVATOR_INSERT_REQUEUE 4
186 #define ELEVATOR_INSERT_FLUSH 5
187 #define ELEVATOR_INSERT_SORT_MERGE 6
190 * return values from elevator_may_queue_fn
198 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
199 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
202 * Hack to reuse the csd.list list_head as the fifo time holder while
203 * the request is in the io scheduler. Saves an unsigned long in rq.
205 #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
206 #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
207 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
208 #define rq_fifo_clear(rq) do { \
209 list_del_init(&(rq)->queuelist); \
210 INIT_LIST_HEAD(&(rq)->csd.list); \
213 #else /* CONFIG_BLOCK */
215 static inline void load_default_elevator_module(void) { }
217 #endif /* CONFIG_BLOCK */