1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 #include <linux/percpu.h>
6 typedef int (elevator_merge_fn
) (request_queue_t
*, struct request
**,
9 typedef void (elevator_merge_req_fn
) (request_queue_t
*, struct request
*, struct request
*);
11 typedef void (elevator_merged_fn
) (request_queue_t
*, struct request
*, int);
13 typedef int (elevator_dispatch_fn
) (request_queue_t
*, int);
15 typedef void (elevator_add_req_fn
) (request_queue_t
*, struct request
*);
16 typedef int (elevator_queue_empty_fn
) (request_queue_t
*);
17 typedef struct request
*(elevator_request_list_fn
) (request_queue_t
*, struct request
*);
18 typedef void (elevator_completed_req_fn
) (request_queue_t
*, struct request
*);
19 typedef int (elevator_may_queue_fn
) (request_queue_t
*, int);
21 typedef int (elevator_set_req_fn
) (request_queue_t
*, struct request
*, gfp_t
);
22 typedef void (elevator_put_req_fn
) (request_queue_t
*, struct request
*);
23 typedef void (elevator_activate_req_fn
) (request_queue_t
*, struct request
*);
24 typedef void (elevator_deactivate_req_fn
) (request_queue_t
*, struct request
*);
26 typedef void *(elevator_init_fn
) (request_queue_t
*, elevator_t
*);
27 typedef void (elevator_exit_fn
) (elevator_t
*);
31 elevator_merge_fn
*elevator_merge_fn
;
32 elevator_merged_fn
*elevator_merged_fn
;
33 elevator_merge_req_fn
*elevator_merge_req_fn
;
35 elevator_dispatch_fn
*elevator_dispatch_fn
;
36 elevator_add_req_fn
*elevator_add_req_fn
;
37 elevator_activate_req_fn
*elevator_activate_req_fn
;
38 elevator_deactivate_req_fn
*elevator_deactivate_req_fn
;
40 elevator_queue_empty_fn
*elevator_queue_empty_fn
;
41 elevator_completed_req_fn
*elevator_completed_req_fn
;
43 elevator_request_list_fn
*elevator_former_req_fn
;
44 elevator_request_list_fn
*elevator_latter_req_fn
;
46 elevator_set_req_fn
*elevator_set_req_fn
;
47 elevator_put_req_fn
*elevator_put_req_fn
;
49 elevator_may_queue_fn
*elevator_may_queue_fn
;
51 elevator_init_fn
*elevator_init_fn
;
52 elevator_exit_fn
*elevator_exit_fn
;
53 void (*trim
)(struct io_context
*);
56 #define ELV_NAME_MAX (16)
59 struct attribute attr
;
60 ssize_t (*show
)(elevator_t
*, char *);
61 ssize_t (*store
)(elevator_t
*, const char *, size_t);
65 * identifies an elevator type, such as AS or deadline
69 struct list_head list
;
70 struct elevator_ops ops
;
71 struct elevator_type
*elevator_type
;
72 struct elv_fs_entry
*elevator_attrs
;
73 char elevator_name
[ELV_NAME_MAX
];
74 struct module
*elevator_owner
;
78 * each queue has an elevator_queue associated with it
82 struct elevator_ops
*ops
;
85 struct elevator_type
*elevator_type
;
86 struct mutex sysfs_lock
;
87 struct hlist_head
*hash
;
91 * block elevator interface
93 extern void elv_dispatch_sort(request_queue_t
*, struct request
*);
94 extern void elv_dispatch_add_tail(request_queue_t
*, struct request
*);
95 extern void elv_add_request(request_queue_t
*, struct request
*, int, int);
96 extern void __elv_add_request(request_queue_t
*, struct request
*, int, int);
97 extern void elv_insert(request_queue_t
*, struct request
*, int);
98 extern int elv_merge(request_queue_t
*, struct request
**, struct bio
*);
99 extern void elv_merge_requests(request_queue_t
*, struct request
*,
101 extern void elv_merged_request(request_queue_t
*, struct request
*, int);
102 extern void elv_dequeue_request(request_queue_t
*, struct request
*);
103 extern void elv_requeue_request(request_queue_t
*, struct request
*);
104 extern int elv_queue_empty(request_queue_t
*);
105 extern struct request
*elv_next_request(struct request_queue
*q
);
106 extern struct request
*elv_former_request(request_queue_t
*, struct request
*);
107 extern struct request
*elv_latter_request(request_queue_t
*, struct request
*);
108 extern int elv_register_queue(request_queue_t
*q
);
109 extern void elv_unregister_queue(request_queue_t
*q
);
110 extern int elv_may_queue(request_queue_t
*, int);
111 extern void elv_completed_request(request_queue_t
*, struct request
*);
112 extern int elv_set_request(request_queue_t
*, struct request
*, gfp_t
);
113 extern void elv_put_request(request_queue_t
*, struct request
*);
116 * io scheduler registration
118 extern int elv_register(struct elevator_type
*);
119 extern void elv_unregister(struct elevator_type
*);
122 * io scheduler sysfs switching
124 extern ssize_t
elv_iosched_show(request_queue_t
*, char *);
125 extern ssize_t
elv_iosched_store(request_queue_t
*, const char *, size_t);
127 extern int elevator_init(request_queue_t
*, char *);
128 extern void elevator_exit(elevator_t
*);
129 extern int elv_rq_merge_ok(struct request
*, struct bio
*);
134 extern struct request
*elv_rb_former_request(request_queue_t
*, struct request
*);
135 extern struct request
*elv_rb_latter_request(request_queue_t
*, struct request
*);
138 * rb support functions.
140 extern struct request
*elv_rb_add(struct rb_root
*, struct request
*);
141 extern void elv_rb_del(struct rb_root
*, struct request
*);
142 extern struct request
*elv_rb_find(struct rb_root
*, sector_t
);
145 * Return values from elevator merger
147 #define ELEVATOR_NO_MERGE 0
148 #define ELEVATOR_FRONT_MERGE 1
149 #define ELEVATOR_BACK_MERGE 2
152 * Insertion selection
154 #define ELEVATOR_INSERT_FRONT 1
155 #define ELEVATOR_INSERT_BACK 2
156 #define ELEVATOR_INSERT_SORT 3
157 #define ELEVATOR_INSERT_REQUEUE 4
160 * return values from elevator_may_queue_fn
168 #define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
169 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
172 * Hack to reuse the donelist list_head as the fifo time holder while
173 * the request is in the io scheduler. Saves an unsigned long in rq.
175 #define rq_fifo_time(rq) ((unsigned long) (rq)->donelist.next)
176 #define rq_set_fifo_time(rq,exp) ((rq)->donelist.next = (void *) (exp))
177 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
178 #define rq_fifo_clear(rq) do { \
179 list_del_init(&(rq)->queuelist); \
180 INIT_LIST_HEAD(&(rq)->donelist); \
184 * io context count accounting
186 #define elv_ioc_count_mod(name, __val) \
189 __get_cpu_var(name) += (__val); \
193 #define elv_ioc_count_inc(name) elv_ioc_count_mod(name, 1)
194 #define elv_ioc_count_dec(name) elv_ioc_count_mod(name, -1)
196 #define elv_ioc_count_read(name) \
198 unsigned long __val = 0; \
201 for_each_possible_cpu(__cpu) \
202 __val += per_cpu(name, __cpu); \