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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_ELEVATOR_H
2#define _LINUX_ELEVATOR_H
3
Jens Axboe4a893e82006-07-22 15:37:43 +02004#include <linux/percpu.h>
5
David Howells93614012006-09-30 20:45:40 +02006#ifdef CONFIG_BLOCK
7
Jens Axboe165125e2007-07-24 09:28:11 +02008typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 struct bio *);
10
Jens Axboe165125e2007-07-24 09:28:11 +020011typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070012
Jens Axboe165125e2007-07-24 09:28:11 +020013typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
Jens Axboe165125e2007-07-24 09:28:11 +020015typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *);
Jens Axboeda775262006-12-20 11:04:12 +010016
Divyesh Shah812d4022010-04-08 21:14:23 -070017typedef void (elevator_bio_merged_fn) (struct request_queue *,
18 struct request *, struct bio *);
19
Jens Axboe165125e2007-07-24 09:28:11 +020020typedef int (elevator_dispatch_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
Jens Axboe165125e2007-07-24 09:28:11 +020022typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020023typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
24typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
25typedef int (elevator_may_queue_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070026
Jens Axboe165125e2007-07-24 09:28:11 +020027typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t);
Jens Axboebb37b942006-12-01 10:42:33 +010028typedef void (elevator_put_req_fn) (struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020029typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
30typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
Jens Axboe165125e2007-07-24 09:28:11 +020032typedef void *(elevator_init_fn) (struct request_queue *);
Jens Axboeb374d182008-10-31 10:05:07 +010033typedef void (elevator_exit_fn) (struct elevator_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35struct elevator_ops
36{
37 elevator_merge_fn *elevator_merge_fn;
38 elevator_merged_fn *elevator_merged_fn;
39 elevator_merge_req_fn *elevator_merge_req_fn;
Jens Axboeda775262006-12-20 11:04:12 +010040 elevator_allow_merge_fn *elevator_allow_merge_fn;
Divyesh Shah812d4022010-04-08 21:14:23 -070041 elevator_bio_merged_fn *elevator_bio_merged_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Tejun Heo8922e162005-10-20 16:23:44 +020043 elevator_dispatch_fn *elevator_dispatch_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 elevator_add_req_fn *elevator_add_req_fn;
Tejun Heo8922e162005-10-20 16:23:44 +020045 elevator_activate_req_fn *elevator_activate_req_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
47
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 elevator_completed_req_fn *elevator_completed_req_fn;
49
50 elevator_request_list_fn *elevator_former_req_fn;
51 elevator_request_list_fn *elevator_latter_req_fn;
52
53 elevator_set_req_fn *elevator_set_req_fn;
54 elevator_put_req_fn *elevator_put_req_fn;
55
56 elevator_may_queue_fn *elevator_may_queue_fn;
57
58 elevator_init_fn *elevator_init_fn;
59 elevator_exit_fn *elevator_exit_fn;
Al Viroe17a9482006-03-18 13:21:20 -050060 void (*trim)(struct io_context *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061};
62
63#define ELV_NAME_MAX (16)
64
Al Viroe572ec72006-03-18 22:27:18 -050065struct elv_fs_entry {
66 struct attribute attr;
Jens Axboeb374d182008-10-31 10:05:07 +010067 ssize_t (*show)(struct elevator_queue *, char *);
68 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
Al Viroe572ec72006-03-18 22:27:18 -050069};
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071/*
72 * identifies an elevator type, such as AS or deadline
73 */
74struct elevator_type
75{
76 struct list_head list;
77 struct elevator_ops ops;
Al Viroe572ec72006-03-18 22:27:18 -050078 struct elv_fs_entry *elevator_attrs;
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 char elevator_name[ELV_NAME_MAX];
80 struct module *elevator_owner;
81};
82
83/*
Adrian Bunk54069582006-01-10 00:09:36 +010084 * each queue has an elevator_queue associated with it
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 */
86struct elevator_queue
87{
88 struct elevator_ops *ops;
89 void *elevator_data;
90 struct kobject kobj;
91 struct elevator_type *elevator_type;
Al Viro3d1ab402006-03-18 18:35:43 -050092 struct mutex sysfs_lock;
Jens Axboe98170642006-07-28 09:23:08 +020093 struct hlist_head *hash;
Jens Axboe430c62f2010-10-07 09:35:16 +020094 unsigned int registered:1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095};
96
97/*
98 * block elevator interface
99 */
Jens Axboe165125e2007-07-24 09:28:11 +0200100extern void elv_dispatch_sort(struct request_queue *, struct request *);
101extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
Jens Axboe7eaceac2011-03-10 08:52:07 +0100102extern void elv_add_request(struct request_queue *, struct request *, int);
103extern void __elv_add_request(struct request_queue *, struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200104extern int elv_merge(struct request_queue *, struct request **, struct bio *);
Jens Axboe73c10102011-03-08 13:19:51 +0100105extern int elv_try_merge(struct request *, struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200106extern void elv_merge_requests(struct request_queue *, struct request *,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200108extern void elv_merged_request(struct request_queue *, struct request *, int);
Divyesh Shah812d4022010-04-08 21:14:23 -0700109extern void elv_bio_merged(struct request_queue *q, struct request *,
110 struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200111extern void elv_requeue_request(struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200112extern struct request *elv_former_request(struct request_queue *, struct request *);
113extern struct request *elv_latter_request(struct request_queue *, struct request *);
114extern int elv_register_queue(struct request_queue *q);
115extern void elv_unregister_queue(struct request_queue *q);
116extern int elv_may_queue(struct request_queue *, int);
Mike Anderson11914a52008-09-13 20:31:27 +0200117extern void elv_abort_queue(struct request_queue *);
Jens Axboe165125e2007-07-24 09:28:11 +0200118extern void elv_completed_request(struct request_queue *, struct request *);
119extern int elv_set_request(struct request_queue *, struct request *, gfp_t);
120extern void elv_put_request(struct request_queue *, struct request *);
Jerome Marchand26308ea2009-03-27 10:31:51 +0100121extern void elv_drain_elevator(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
123/*
124 * io scheduler registration
125 */
Adrian Bunk2fdd82b2007-12-12 18:51:56 +0100126extern void elv_register(struct elevator_type *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127extern void elv_unregister(struct elevator_type *);
128
129/*
130 * io scheduler sysfs switching
131 */
Jens Axboe165125e2007-07-24 09:28:11 +0200132extern ssize_t elv_iosched_show(struct request_queue *, char *);
133extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134
Jens Axboe165125e2007-07-24 09:28:11 +0200135extern int elevator_init(struct request_queue *, char *);
Jens Axboeb374d182008-10-31 10:05:07 +0100136extern void elevator_exit(struct elevator_queue *);
Jens Axboe5dd531a2010-08-23 13:52:19 +0200137extern int elevator_change(struct request_queue *, const char *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138extern int elv_rq_merge_ok(struct request *, struct bio *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139
140/*
Jens Axboe2e662b62006-07-13 11:55:04 +0200141 * Helper functions.
142 */
Jens Axboe165125e2007-07-24 09:28:11 +0200143extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
144extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200145
146/*
147 * rb support functions.
148 */
Jeff Moyer796d5112011-06-02 21:19:05 +0200149extern void elv_rb_add(struct rb_root *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200150extern void elv_rb_del(struct rb_root *, struct request *);
151extern struct request *elv_rb_find(struct rb_root *, sector_t);
152
153/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 * Return values from elevator merger
155 */
156#define ELEVATOR_NO_MERGE 0
157#define ELEVATOR_FRONT_MERGE 1
158#define ELEVATOR_BACK_MERGE 2
159
160/*
161 * Insertion selection
162 */
163#define ELEVATOR_INSERT_FRONT 1
164#define ELEVATOR_INSERT_BACK 2
165#define ELEVATOR_INSERT_SORT 3
Tejun Heo797e7db2006-01-06 09:51:03 +0100166#define ELEVATOR_INSERT_REQUEUE 4
Tejun Heoae1b1532011-01-25 12:43:54 +0100167#define ELEVATOR_INSERT_FLUSH 5
Jens Axboe5e84ea32011-03-21 10:14:27 +0100168#define ELEVATOR_INSERT_SORT_MERGE 6
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
170/*
171 * return values from elevator_may_queue_fn
172 */
173enum {
174 ELV_MQUEUE_MAY,
175 ELV_MQUEUE_NO,
176 ELV_MQUEUE_MUST,
177};
178
Tejun Heo2e46e8b2009-05-07 22:24:41 +0900179#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
Jens Axboe2e662b62006-07-13 11:55:04 +0200180#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
Jens Axboe1b47f532005-10-20 16:37:00 +0200181
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200182/*
Jens Axboec7c22e42008-09-13 20:26:01 +0200183 * Hack to reuse the csd.list list_head as the fifo time holder while
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200184 * the request is in the io scheduler. Saves an unsigned long in rq.
185 */
Jens Axboec7c22e42008-09-13 20:26:01 +0200186#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))
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200188#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
189#define rq_fifo_clear(rq) do { \
190 list_del_init(&(rq)->queuelist); \
Jens Axboec7c22e42008-09-13 20:26:01 +0200191 INIT_LIST_HEAD(&(rq)->csd.list); \
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200192 } while (0)
193
Jens Axboe4a893e82006-07-22 15:37:43 +0200194/*
195 * io context count accounting
196 */
Christoph Lameter909ea962010-12-08 16:22:55 +0100197#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)
Jens Axboe4a893e82006-07-22 15:37:43 +0200200
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; \
209})
210
David Howells93614012006-09-30 20:45:40 +0200211#endif /* CONFIG_BLOCK */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212#endif