r6040: make printks consistent with DRV_NAME
[linux-2.6/linux-2.6-openrd.git] / include / linux / elevator.h
blob7a204256b1550f889f96a666808e805fe749c186
1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 #include <linux/percpu.h>
6 #ifdef CONFIG_BLOCK
8 typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
9 struct bio *);
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 *);
33 struct elevator_ops
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)
63 struct elv_fs_entry {
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
72 struct elevator_type
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
84 struct elevator_queue
86 struct elevator_ops *ops;
87 void *elevator_data;
88 struct kobject kobj;
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 *,
104 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 *);
137 * Helper functions.
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
167 enum {
168 ELV_MQUEUE_MAY,
169 ELV_MQUEUE_NO,
170 ELV_MQUEUE_MUST,
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); \
186 } while (0)
189 * io context count accounting
191 #define elv_ioc_count_mod(name, __val) \
192 do { \
193 preempt_disable(); \
194 __get_cpu_var(name) += (__val); \
195 preempt_enable(); \
196 } while (0)
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) \
202 ({ \
203 unsigned long __val = 0; \
204 int __cpu; \
205 smp_wmb(); \
206 for_each_possible_cpu(__cpu) \
207 __val += per_cpu(name, __cpu); \
208 __val; \
211 #endif /* CONFIG_BLOCK */
212 #endif