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 int (elevator_dispatch_fn
) (struct request_queue
*, int);
19 typedef void (elevator_add_req_fn
) (struct request_queue
*, struct request
*);
20 typedef int (elevator_queue_empty_fn
) (struct request_queue
*);
21 typedef struct request
*(elevator_request_list_fn
) (struct request_queue
*, struct request
*);
22 typedef void (elevator_completed_req_fn
) (struct request_queue
*, struct request
*);
23 typedef int (elevator_may_queue_fn
) (struct request_queue
*, int);
25 typedef int (elevator_set_req_fn
) (struct request_queue
*, struct request
*, gfp_t
);
26 typedef void (elevator_put_req_fn
) (struct request
*);
27 typedef void (elevator_activate_req_fn
) (struct request_queue
*, struct request
*);
28 typedef void (elevator_deactivate_req_fn
) (struct request_queue
*, struct request
*);
30 typedef void *(elevator_init_fn
) (struct request_queue
*);
31 typedef void (elevator_exit_fn
) (struct elevator_queue
*);
35 elevator_merge_fn
*elevator_merge_fn
;
36 elevator_merged_fn
*elevator_merged_fn
;
37 elevator_merge_req_fn
*elevator_merge_req_fn
;
38 elevator_allow_merge_fn
*elevator_allow_merge_fn
;
40 elevator_dispatch_fn
*elevator_dispatch_fn
;
41 elevator_add_req_fn
*elevator_add_req_fn
;
42 elevator_activate_req_fn
*elevator_activate_req_fn
;
43 elevator_deactivate_req_fn
*elevator_deactivate_req_fn
;
45 elevator_queue_empty_fn
*elevator_queue_empty_fn
;
46 elevator_completed_req_fn
*elevator_completed_req_fn
;
48 elevator_request_list_fn
*elevator_former_req_fn
;
49 elevator_request_list_fn
*elevator_latter_req_fn
;
51 elevator_set_req_fn
*elevator_set_req_fn
;
52 elevator_put_req_fn
*elevator_put_req_fn
;
54 elevator_may_queue_fn
*elevator_may_queue_fn
;
56 elevator_init_fn
*elevator_init_fn
;
57 elevator_exit_fn
*elevator_exit_fn
;
58 void (*trim
)(struct io_context
*);
61 #define ELV_NAME_MAX (16)
64 struct attribute attr
;
65 ssize_t (*show
)(struct elevator_queue
*, char *);
66 ssize_t (*store
)(struct elevator_queue
*, const char *, size_t);
70 * identifies an elevator type, such as AS or deadline
74 struct list_head list
;
75 struct elevator_ops ops
;
76 struct elv_fs_entry
*elevator_attrs
;
77 char elevator_name
[ELV_NAME_MAX
];
78 struct module
*elevator_owner
;
82 * each queue has an elevator_queue associated with it
86 struct elevator_ops
*ops
;
89 struct elevator_type
*elevator_type
;
90 struct mutex sysfs_lock
;
91 struct hlist_head
*hash
;
95 * block elevator interface
97 extern void elv_dispatch_sort(struct request_queue
*, struct request
*);
98 extern void elv_dispatch_add_tail(struct request_queue
*, struct request
*);
99 extern void elv_add_request(struct request_queue
*, struct request
*, int, int);
100 extern void __elv_add_request(struct request_queue
*, struct request
*, int, int);
101 extern void elv_insert(struct request_queue
*, struct request
*, int);
102 extern int elv_merge(struct request_queue
*, struct request
**, struct bio
*);
103 extern void elv_merge_requests(struct request_queue
*, struct request
*,
105 extern void elv_merged_request(struct request_queue
*, struct request
*, int);
106 extern void elv_dequeue_request(struct request_queue
*, struct request
*);
107 extern void elv_requeue_request(struct request_queue
*, struct request
*);
108 extern int elv_queue_empty(struct request_queue
*);
109 extern struct request
*elv_next_request(struct request_queue
*q
);
110 extern struct request
*elv_former_request(struct request_queue
*, struct request
*);
111 extern struct request
*elv_latter_request(struct request_queue
*, struct request
*);
112 extern int elv_register_queue(struct request_queue
*q
);
113 extern void elv_unregister_queue(struct request_queue
*q
);
114 extern int elv_may_queue(struct request_queue
*, int);
115 extern void elv_abort_queue(struct request_queue
*);
116 extern void elv_completed_request(struct request_queue
*, struct request
*);
117 extern int elv_set_request(struct request_queue
*, struct request
*, gfp_t
);
118 extern void elv_put_request(struct request_queue
*, struct request
*);
121 * io scheduler registration
123 extern void elv_register(struct elevator_type
*);
124 extern void elv_unregister(struct elevator_type
*);
127 * io scheduler sysfs switching
129 extern ssize_t
elv_iosched_show(struct request_queue
*, char *);
130 extern ssize_t
elv_iosched_store(struct request_queue
*, const char *, size_t);
132 extern int elevator_init(struct request_queue
*, char *);
133 extern void elevator_exit(struct elevator_queue
*);
134 extern int elv_rq_merge_ok(struct request
*, struct bio
*);
139 extern struct request
*elv_rb_former_request(struct request_queue
*, struct request
*);
140 extern struct request
*elv_rb_latter_request(struct request_queue
*, struct request
*);
143 * rb support functions.
145 extern struct request
*elv_rb_add(struct rb_root
*, struct request
*);
146 extern void elv_rb_del(struct rb_root
*, struct request
*);
147 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
150 * Return values from elevator merger
152 #define ELEVATOR_NO_MERGE 0
153 #define ELEVATOR_FRONT_MERGE 1
154 #define ELEVATOR_BACK_MERGE 2
157 * Insertion selection
159 #define ELEVATOR_INSERT_FRONT 1
160 #define ELEVATOR_INSERT_BACK 2
161 #define ELEVATOR_INSERT_SORT 3
162 #define ELEVATOR_INSERT_REQUEUE 4
165 * return values from elevator_may_queue_fn
173 #define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
174 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
177 * Hack to reuse the csd.list list_head as the fifo time holder while
178 * the request is in the io scheduler. Saves an unsigned long in rq.
180 #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
181 #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
182 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
183 #define rq_fifo_clear(rq) do { \
184 list_del_init(&(rq)->queuelist); \
185 INIT_LIST_HEAD(&(rq)->csd.list); \
189 * io context count accounting
191 #define elv_ioc_count_mod(name, __val) \
194 __get_cpu_var(name) += (__val); \
198 #define elv_ioc_count_inc(name) elv_ioc_count_mod(name, 1)
199 #define elv_ioc_count_dec(name) elv_ioc_count_mod(name, -1)
201 #define elv_ioc_count_read(name) \
203 unsigned long __val = 0; \
206 for_each_possible_cpu(__cpu) \
207 __val += per_cpu(name, __cpu); \
211 #endif /* CONFIG_BLOCK */