1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 typedef int (elevator_merge_fn
) (request_queue_t
*, struct request
**,
7 typedef void (elevator_merge_req_fn
) (request_queue_t
*, struct request
*, struct request
*);
9 typedef void (elevator_merged_fn
) (request_queue_t
*, struct request
*, int);
11 typedef int (elevator_dispatch_fn
) (request_queue_t
*, int);
13 typedef void (elevator_add_req_fn
) (request_queue_t
*, struct request
*);
14 typedef int (elevator_queue_empty_fn
) (request_queue_t
*);
15 typedef struct request
*(elevator_request_list_fn
) (request_queue_t
*, struct request
*);
16 typedef void (elevator_completed_req_fn
) (request_queue_t
*, struct request
*);
17 typedef int (elevator_may_queue_fn
) (request_queue_t
*, int);
19 typedef int (elevator_set_req_fn
) (request_queue_t
*, struct request
*, gfp_t
);
20 typedef void (elevator_put_req_fn
) (request_queue_t
*, struct request
*);
21 typedef void (elevator_activate_req_fn
) (request_queue_t
*, struct request
*);
22 typedef void (elevator_deactivate_req_fn
) (request_queue_t
*, struct request
*);
24 typedef void *(elevator_init_fn
) (request_queue_t
*, elevator_t
*);
25 typedef void (elevator_exit_fn
) (elevator_t
*);
29 elevator_merge_fn
*elevator_merge_fn
;
30 elevator_merged_fn
*elevator_merged_fn
;
31 elevator_merge_req_fn
*elevator_merge_req_fn
;
33 elevator_dispatch_fn
*elevator_dispatch_fn
;
34 elevator_add_req_fn
*elevator_add_req_fn
;
35 elevator_activate_req_fn
*elevator_activate_req_fn
;
36 elevator_deactivate_req_fn
*elevator_deactivate_req_fn
;
38 elevator_queue_empty_fn
*elevator_queue_empty_fn
;
39 elevator_completed_req_fn
*elevator_completed_req_fn
;
41 elevator_request_list_fn
*elevator_former_req_fn
;
42 elevator_request_list_fn
*elevator_latter_req_fn
;
44 elevator_set_req_fn
*elevator_set_req_fn
;
45 elevator_put_req_fn
*elevator_put_req_fn
;
47 elevator_may_queue_fn
*elevator_may_queue_fn
;
49 elevator_init_fn
*elevator_init_fn
;
50 elevator_exit_fn
*elevator_exit_fn
;
51 void (*trim
)(struct io_context
*);
54 #define ELV_NAME_MAX (16)
57 struct attribute attr
;
58 ssize_t (*show
)(elevator_t
*, char *);
59 ssize_t (*store
)(elevator_t
*, const char *, size_t);
63 * identifies an elevator type, such as AS or deadline
67 struct list_head list
;
68 struct elevator_ops ops
;
69 struct elevator_type
*elevator_type
;
70 struct elv_fs_entry
*elevator_attrs
;
71 char elevator_name
[ELV_NAME_MAX
];
72 struct module
*elevator_owner
;
76 * each queue has an elevator_queue associated with it
80 struct elevator_ops
*ops
;
83 struct elevator_type
*elevator_type
;
84 struct mutex sysfs_lock
;
85 struct hlist_head
*hash
;
89 * block elevator interface
91 extern void elv_dispatch_sort(request_queue_t
*, struct request
*);
92 extern void elv_dispatch_add_tail(request_queue_t
*, struct request
*);
93 extern void elv_add_request(request_queue_t
*, struct request
*, int, int);
94 extern void __elv_add_request(request_queue_t
*, struct request
*, int, int);
95 extern void elv_insert(request_queue_t
*, struct request
*, int);
96 extern int elv_merge(request_queue_t
*, struct request
**, struct bio
*);
97 extern void elv_merge_requests(request_queue_t
*, struct request
*,
99 extern void elv_merged_request(request_queue_t
*, struct request
*, int);
100 extern void elv_dequeue_request(request_queue_t
*, struct request
*);
101 extern void elv_requeue_request(request_queue_t
*, struct request
*);
102 extern int elv_queue_empty(request_queue_t
*);
103 extern struct request
*elv_next_request(struct request_queue
*q
);
104 extern struct request
*elv_former_request(request_queue_t
*, struct request
*);
105 extern struct request
*elv_latter_request(request_queue_t
*, struct request
*);
106 extern int elv_register_queue(request_queue_t
*q
);
107 extern void elv_unregister_queue(request_queue_t
*q
);
108 extern int elv_may_queue(request_queue_t
*, int);
109 extern void elv_completed_request(request_queue_t
*, struct request
*);
110 extern int elv_set_request(request_queue_t
*, struct request
*, gfp_t
);
111 extern void elv_put_request(request_queue_t
*, struct request
*);
114 * io scheduler registration
116 extern int elv_register(struct elevator_type
*);
117 extern void elv_unregister(struct elevator_type
*);
120 * io scheduler sysfs switching
122 extern ssize_t
elv_iosched_show(request_queue_t
*, char *);
123 extern ssize_t
elv_iosched_store(request_queue_t
*, const char *, size_t);
125 extern int elevator_init(request_queue_t
*, char *);
126 extern void elevator_exit(elevator_t
*);
127 extern int elv_rq_merge_ok(struct request
*, struct bio
*);
132 extern struct request
*elv_rb_former_request(request_queue_t
*, struct request
*);
133 extern struct request
*elv_rb_latter_request(request_queue_t
*, struct request
*);
136 * rb support functions.
138 extern struct request
*elv_rb_add(struct rb_root
*, struct request
*);
139 extern void elv_rb_del(struct rb_root
*, struct request
*);
140 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
143 * Return values from elevator merger
145 #define ELEVATOR_NO_MERGE 0
146 #define ELEVATOR_FRONT_MERGE 1
147 #define ELEVATOR_BACK_MERGE 2
150 * Insertion selection
152 #define ELEVATOR_INSERT_FRONT 1
153 #define ELEVATOR_INSERT_BACK 2
154 #define ELEVATOR_INSERT_SORT 3
155 #define ELEVATOR_INSERT_REQUEUE 4
158 * return values from elevator_may_queue_fn
166 #define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
167 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
170 * Hack to reuse the donelist list_head as the fifo time holder while
171 * the request is in the io scheduler. Saves an unsigned long in rq.
173 #define rq_fifo_time(rq) ((unsigned long) (rq)->donelist.next)
174 #define rq_set_fifo_time(rq,exp) ((rq)->donelist.next = (void *) (exp))
175 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
176 #define rq_fifo_clear(rq) do { \
177 list_del_init(&(rq)->queuelist); \
178 INIT_LIST_HEAD(&(rq)->donelist); \