ASoC: Only run power_check() on a widget once per run
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / include / linux / elevator.h
blobd800d5142184216bab18fb1858452fd896e85612
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 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 *);
35 struct elevator_ops
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;
41 elevator_bio_merged_fn *elevator_bio_merged_fn;
43 elevator_dispatch_fn *elevator_dispatch_fn;
44 elevator_add_req_fn *elevator_add_req_fn;
45 elevator_activate_req_fn *elevator_activate_req_fn;
46 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
48 elevator_completed_req_fn *elevator_completed_req_fn;
50 elevator_request_list_fn *elevator_former_req_fn;
51 elevator_request_list_fn *elevator_latter_req_fn;
53 elevator_set_req_fn *elevator_set_req_fn;
54 elevator_put_req_fn *elevator_put_req_fn;
56 elevator_may_queue_fn *elevator_may_queue_fn;
58 elevator_init_fn *elevator_init_fn;
59 elevator_exit_fn *elevator_exit_fn;
60 void (*trim)(struct io_context *);
63 #define ELV_NAME_MAX (16)
65 struct elv_fs_entry {
66 struct attribute attr;
67 ssize_t (*show)(struct elevator_queue *, char *);
68 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
72 * identifies an elevator type, such as AS or deadline
74 struct elevator_type
76 struct list_head list;
77 struct elevator_ops ops;
78 struct elv_fs_entry *elevator_attrs;
79 char elevator_name[ELV_NAME_MAX];
80 struct module *elevator_owner;
84 * each queue has an elevator_queue associated with it
86 struct elevator_queue
88 struct elevator_ops *ops;
89 void *elevator_data;
90 struct kobject kobj;
91 struct elevator_type *elevator_type;
92 struct mutex sysfs_lock;
93 struct hlist_head *hash;
94 unsigned int registered:1;
98 * block elevator interface
100 extern void elv_dispatch_sort(struct request_queue *, struct request *);
101 extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
102 extern void elv_add_request(struct request_queue *, struct request *, int);
103 extern void __elv_add_request(struct request_queue *, struct request *, int);
104 extern int elv_merge(struct request_queue *, struct request **, struct bio *);
105 extern int elv_try_merge(struct request *, struct bio *);
106 extern void elv_merge_requests(struct request_queue *, struct request *,
107 struct request *);
108 extern void elv_merged_request(struct request_queue *, struct request *, int);
109 extern void elv_bio_merged(struct request_queue *q, struct request *,
110 struct bio *);
111 extern void elv_requeue_request(struct request_queue *, struct request *);
112 extern struct request *elv_former_request(struct request_queue *, struct request *);
113 extern struct request *elv_latter_request(struct request_queue *, struct request *);
114 extern int elv_register_queue(struct request_queue *q);
115 extern void elv_unregister_queue(struct request_queue *q);
116 extern int elv_may_queue(struct request_queue *, int);
117 extern void elv_abort_queue(struct request_queue *);
118 extern void elv_completed_request(struct request_queue *, struct request *);
119 extern int elv_set_request(struct request_queue *, struct request *, gfp_t);
120 extern void elv_put_request(struct request_queue *, struct request *);
121 extern void elv_drain_elevator(struct request_queue *);
124 * io scheduler registration
126 extern void elv_register(struct elevator_type *);
127 extern void elv_unregister(struct elevator_type *);
130 * io scheduler sysfs switching
132 extern ssize_t elv_iosched_show(struct request_queue *, char *);
133 extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
135 extern int elevator_init(struct request_queue *, char *);
136 extern void elevator_exit(struct elevator_queue *);
137 extern int elevator_change(struct request_queue *, const char *);
138 extern int elv_rq_merge_ok(struct request *, struct bio *);
141 * Helper functions.
143 extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
144 extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
147 * rb support functions.
149 extern void elv_rb_add(struct rb_root *, struct request *);
150 extern void elv_rb_del(struct rb_root *, struct request *);
151 extern struct request *elv_rb_find(struct rb_root *, sector_t);
154 * Return values from elevator merger
156 #define ELEVATOR_NO_MERGE 0
157 #define ELEVATOR_FRONT_MERGE 1
158 #define ELEVATOR_BACK_MERGE 2
161 * Insertion selection
163 #define ELEVATOR_INSERT_FRONT 1
164 #define ELEVATOR_INSERT_BACK 2
165 #define ELEVATOR_INSERT_SORT 3
166 #define ELEVATOR_INSERT_REQUEUE 4
167 #define ELEVATOR_INSERT_FLUSH 5
168 #define ELEVATOR_INSERT_SORT_MERGE 6
171 * return values from elevator_may_queue_fn
173 enum {
174 ELV_MQUEUE_MAY,
175 ELV_MQUEUE_NO,
176 ELV_MQUEUE_MUST,
179 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
180 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
183 * Hack to reuse the csd.list list_head as the fifo time holder while
184 * the request is in the io scheduler. Saves an unsigned long in rq.
186 #define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
187 #define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
188 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
189 #define rq_fifo_clear(rq) do { \
190 list_del_init(&(rq)->queuelist); \
191 INIT_LIST_HEAD(&(rq)->csd.list); \
192 } while (0)
195 * io context count accounting
197 #define elv_ioc_count_mod(name, __val) this_cpu_add(name, __val)
198 #define elv_ioc_count_inc(name) this_cpu_inc(name)
199 #define elv_ioc_count_dec(name) this_cpu_dec(name)
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