1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 #include <linux/percpu.h>
8 typedef int (elevator_merge_fn
) (struct request_queue
*, struct request
**,
11 typedef void (elevator_merge_req_fn
) (struct request_queue
*, struct request
*, struct request
*);
13 typedef void (elevator_merged_fn
) (struct request_queue
*, struct request
*, int);
15 typedef int (elevator_allow_merge_fn
) (struct request_queue
*, struct request
*, struct bio
*);
17 typedef void (elevator_bio_merged_fn
) (struct request_queue
*,
18 struct request
*, struct bio
*);
20 typedef int (elevator_dispatch_fn
) (struct request_queue
*, int);
22 typedef void (elevator_add_req_fn
) (struct request_queue
*, struct request
*);
23 typedef struct request
*(elevator_request_list_fn
) (struct request_queue
*, struct request
*);
24 typedef void (elevator_completed_req_fn
) (struct request_queue
*, struct request
*);
25 typedef int (elevator_may_queue_fn
) (struct request_queue
*, int);
27 typedef int (elevator_set_req_fn
) (struct request_queue
*, struct request
*, gfp_t
);
28 typedef void (elevator_put_req_fn
) (struct request
*);
29 typedef void (elevator_activate_req_fn
) (struct request_queue
*, struct request
*);
30 typedef void (elevator_deactivate_req_fn
) (struct request_queue
*, struct request
*);
32 typedef void *(elevator_init_fn
) (struct request_queue
*);
33 typedef void (elevator_exit_fn
) (struct elevator_queue
*);
37 elevator_merge_fn
*elevator_merge_fn
;
38 elevator_merged_fn
*elevator_merged_fn
;
39 elevator_merge_req_fn
*elevator_merge_req_fn
;
40 elevator_allow_merge_fn
*elevator_allow_merge_fn
;
43 * Used for both plugged list and elevator merging and in the
44 * former case called without queue_lock. Read comment on top of
45 * attempt_plug_merge() for details.
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_set_req_fn
*elevator_set_req_fn
;
60 elevator_put_req_fn
*elevator_put_req_fn
;
62 elevator_may_queue_fn
*elevator_may_queue_fn
;
64 elevator_init_fn
*elevator_init_fn
;
65 elevator_exit_fn
*elevator_exit_fn
;
66 void (*trim
)(struct io_context
*);
69 #define ELV_NAME_MAX (16)
72 struct attribute attr
;
73 ssize_t (*show
)(struct elevator_queue
*, char *);
74 ssize_t (*store
)(struct elevator_queue
*, const char *, size_t);
78 * identifies an elevator type, such as AS or deadline
82 struct list_head list
;
83 struct elevator_ops ops
;
84 struct elv_fs_entry
*elevator_attrs
;
85 char elevator_name
[ELV_NAME_MAX
];
86 struct module
*elevator_owner
;
90 * each queue has an elevator_queue associated with it
94 struct elevator_ops
*ops
;
97 struct elevator_type
*elevator_type
;
98 struct mutex sysfs_lock
;
99 struct hlist_head
*hash
;
100 unsigned int registered
:1;
104 * block elevator interface
106 extern void elv_dispatch_sort(struct request_queue
*, struct request
*);
107 extern void elv_dispatch_add_tail(struct request_queue
*, struct request
*);
108 extern void elv_add_request(struct request_queue
*, struct request
*, int);
109 extern void __elv_add_request(struct request_queue
*, struct request
*, int);
110 extern int elv_merge(struct request_queue
*, struct request
**, struct bio
*);
111 extern int elv_try_merge(struct request
*, struct bio
*);
112 extern void elv_merge_requests(struct request_queue
*, struct request
*,
114 extern void elv_merged_request(struct request_queue
*, struct request
*, int);
115 extern void elv_bio_merged(struct request_queue
*q
, struct request
*,
117 extern void elv_requeue_request(struct request_queue
*, struct request
*);
118 extern struct request
*elv_former_request(struct request_queue
*, struct request
*);
119 extern struct request
*elv_latter_request(struct request_queue
*, struct request
*);
120 extern int elv_register_queue(struct request_queue
*q
);
121 extern void elv_unregister_queue(struct request_queue
*q
);
122 extern int elv_may_queue(struct request_queue
*, int);
123 extern void elv_abort_queue(struct request_queue
*);
124 extern void elv_completed_request(struct request_queue
*, struct request
*);
125 extern int elv_set_request(struct request_queue
*, struct request
*, gfp_t
);
126 extern void elv_put_request(struct request_queue
*, struct request
*);
127 extern void elv_drain_elevator(struct request_queue
*);
130 * io scheduler registration
132 extern void elv_register(struct elevator_type
*);
133 extern void elv_unregister(struct elevator_type
*);
136 * io scheduler sysfs switching
138 extern ssize_t
elv_iosched_show(struct request_queue
*, char *);
139 extern ssize_t
elv_iosched_store(struct request_queue
*, const char *, size_t);
141 extern int elevator_init(struct request_queue
*, char *);
142 extern void elevator_exit(struct elevator_queue
*);
143 extern int elevator_change(struct request_queue
*, const char *);
144 extern int elv_rq_merge_ok(struct request
*, struct bio
*);
149 extern struct request
*elv_rb_former_request(struct request_queue
*, struct request
*);
150 extern struct request
*elv_rb_latter_request(struct request_queue
*, struct request
*);
153 * rb support functions.
155 extern void elv_rb_add(struct rb_root
*, struct request
*);
156 extern void elv_rb_del(struct rb_root
*, struct request
*);
157 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
160 * Return values from elevator merger
162 #define ELEVATOR_NO_MERGE 0
163 #define ELEVATOR_FRONT_MERGE 1
164 #define ELEVATOR_BACK_MERGE 2
167 * Insertion selection
169 #define ELEVATOR_INSERT_FRONT 1
170 #define ELEVATOR_INSERT_BACK 2
171 #define ELEVATOR_INSERT_SORT 3
172 #define ELEVATOR_INSERT_REQUEUE 4
173 #define ELEVATOR_INSERT_FLUSH 5
174 #define ELEVATOR_INSERT_SORT_MERGE 6
177 * return values from elevator_may_queue_fn
185 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
186 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
189 * Hack to reuse the csd.list list_head as the fifo time holder while
190 * the request is in the io scheduler. Saves an unsigned long in rq.
192 #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
193 #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
194 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
195 #define rq_fifo_clear(rq) do { \
196 list_del_init(&(rq)->queuelist); \
197 INIT_LIST_HEAD(&(rq)->csd.list); \
201 * io context count accounting
203 #define elv_ioc_count_mod(name, __val) this_cpu_add(name, __val)
204 #define elv_ioc_count_inc(name) this_cpu_inc(name)
205 #define elv_ioc_count_dec(name) this_cpu_dec(name)
207 #define elv_ioc_count_read(name) \
209 unsigned long __val = 0; \
212 for_each_possible_cpu(__cpu) \
213 __val += per_cpu(name, __cpu); \
217 #endif /* CONFIG_BLOCK */