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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
Tejun Heo7e5a8792011-12-14 00:33:42 +01008struct io_cq;
9
Jens Axboe165125e2007-07-24 09:28:11 +020010typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 struct bio *);
12
Jens Axboe165125e2007-07-24 09:28:11 +020013typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
Jens Axboe165125e2007-07-24 09:28:11 +020015typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070016
Jens Axboe165125e2007-07-24 09:28:11 +020017typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *);
Jens Axboeda775262006-12-20 11:04:12 +010018
Divyesh Shah812d4022010-04-08 21:14:23 -070019typedef void (elevator_bio_merged_fn) (struct request_queue *,
20 struct request *, struct bio *);
21
Jens Axboe165125e2007-07-24 09:28:11 +020022typedef int (elevator_dispatch_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Jens Axboe165125e2007-07-24 09:28:11 +020024typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020025typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
26typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
27typedef int (elevator_may_queue_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
Tejun Heo9b84cac2011-12-14 00:33:42 +010029typedef void (elevator_init_icq_fn) (struct io_cq *);
Tejun Heo7e5a8792011-12-14 00:33:42 +010030typedef void (elevator_exit_icq_fn) (struct io_cq *);
Tejun Heo852c7882012-03-05 13:15:27 -080031typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
32 struct bio *, gfp_t);
Jens Axboebb37b942006-12-01 10:42:33 +010033typedef void (elevator_put_req_fn) (struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020034typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
35typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
Tejun Heob2fab5a2012-03-05 13:14:57 -080037typedef int (elevator_init_fn) (struct request_queue *);
Jens Axboeb374d182008-10-31 10:05:07 +010038typedef void (elevator_exit_fn) (struct elevator_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
40struct elevator_ops
41{
42 elevator_merge_fn *elevator_merge_fn;
43 elevator_merged_fn *elevator_merged_fn;
44 elevator_merge_req_fn *elevator_merge_req_fn;
Jens Axboeda775262006-12-20 11:04:12 +010045 elevator_allow_merge_fn *elevator_allow_merge_fn;
Divyesh Shah812d4022010-04-08 21:14:23 -070046 elevator_bio_merged_fn *elevator_bio_merged_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
Tejun Heo8922e162005-10-20 16:23:44 +020048 elevator_dispatch_fn *elevator_dispatch_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 elevator_add_req_fn *elevator_add_req_fn;
Tejun Heo8922e162005-10-20 16:23:44 +020050 elevator_activate_req_fn *elevator_activate_req_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
52
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 elevator_completed_req_fn *elevator_completed_req_fn;
54
55 elevator_request_list_fn *elevator_former_req_fn;
56 elevator_request_list_fn *elevator_latter_req_fn;
57
Tejun Heof1f8cc92011-12-14 00:33:42 +010058 elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
59 elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
Tejun Heo7e5a8792011-12-14 00:33:42 +010060
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 elevator_set_req_fn *elevator_set_req_fn;
62 elevator_put_req_fn *elevator_put_req_fn;
63
64 elevator_may_queue_fn *elevator_may_queue_fn;
65
66 elevator_init_fn *elevator_init_fn;
67 elevator_exit_fn *elevator_exit_fn;
68};
69
70#define ELV_NAME_MAX (16)
71
Al Viroe572ec72006-03-18 22:27:18 -050072struct elv_fs_entry {
73 struct attribute attr;
Jens Axboeb374d182008-10-31 10:05:07 +010074 ssize_t (*show)(struct elevator_queue *, char *);
75 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
Al Viroe572ec72006-03-18 22:27:18 -050076};
77
Linus Torvalds1da177e2005-04-16 15:20:36 -070078/*
79 * identifies an elevator type, such as AS or deadline
80 */
81struct elevator_type
82{
Tejun Heo3d3c2372011-12-14 00:33:42 +010083 /* managed by elevator core */
84 struct kmem_cache *icq_cache;
85
86 /* fields provided by elevator implementation */
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 struct elevator_ops ops;
Tejun Heof1f8cc92011-12-14 00:33:42 +010088 size_t icq_size; /* see iocontext.h */
89 size_t icq_align; /* ditto */
Al Viroe572ec72006-03-18 22:27:18 -050090 struct elv_fs_entry *elevator_attrs;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 char elevator_name[ELV_NAME_MAX];
92 struct module *elevator_owner;
Tejun Heo3d3c2372011-12-14 00:33:42 +010093
94 /* managed by elevator core */
95 char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
Tejun Heo22f746e2011-12-14 00:33:41 +010096 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097};
98
99/*
Adrian Bunk54069582006-01-10 00:09:36 +0100100 * each queue has an elevator_queue associated with it
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 */
102struct elevator_queue
103{
Tejun Heo22f746e2011-12-14 00:33:41 +0100104 struct elevator_type *type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 void *elevator_data;
106 struct kobject kobj;
Al Viro3d1ab402006-03-18 18:35:43 -0500107 struct mutex sysfs_lock;
Jens Axboe98170642006-07-28 09:23:08 +0200108 struct hlist_head *hash;
Jens Axboe430c62f2010-10-07 09:35:16 +0200109 unsigned int registered:1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110};
111
112/*
113 * block elevator interface
114 */
Jens Axboe165125e2007-07-24 09:28:11 +0200115extern void elv_dispatch_sort(struct request_queue *, struct request *);
116extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
Jens Axboe7eaceac2011-03-10 08:52:07 +0100117extern void elv_add_request(struct request_queue *, struct request *, int);
118extern void __elv_add_request(struct request_queue *, struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200119extern int elv_merge(struct request_queue *, struct request **, struct bio *);
120extern void elv_merge_requests(struct request_queue *, struct request *,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200122extern void elv_merged_request(struct request_queue *, struct request *, int);
Divyesh Shah812d4022010-04-08 21:14:23 -0700123extern void elv_bio_merged(struct request_queue *q, struct request *,
124 struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200125extern void elv_requeue_request(struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200126extern struct request *elv_former_request(struct request_queue *, struct request *);
127extern struct request *elv_latter_request(struct request_queue *, struct request *);
128extern int elv_register_queue(struct request_queue *q);
129extern void elv_unregister_queue(struct request_queue *q);
130extern int elv_may_queue(struct request_queue *, int);
Mike Anderson11914a52008-09-13 20:31:27 +0200131extern void elv_abort_queue(struct request_queue *);
Jens Axboe165125e2007-07-24 09:28:11 +0200132extern void elv_completed_request(struct request_queue *, struct request *);
Tejun Heo852c7882012-03-05 13:15:27 -0800133extern int elv_set_request(struct request_queue *q, struct request *rq,
134 struct bio *bio, gfp_t gfp_mask);
Jens Axboe165125e2007-07-24 09:28:11 +0200135extern void elv_put_request(struct request_queue *, struct request *);
Jerome Marchand26308ea2009-03-27 10:31:51 +0100136extern void elv_drain_elevator(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137
138/*
139 * io scheduler registration
140 */
Tejun Heobb813f42013-01-18 14:05:56 -0800141extern void __init load_default_elevator_module(void);
Tejun Heo3d3c2372011-12-14 00:33:42 +0100142extern int elv_register(struct elevator_type *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143extern void elv_unregister(struct elevator_type *);
144
145/*
146 * io scheduler sysfs switching
147 */
Jens Axboe165125e2007-07-24 09:28:11 +0200148extern ssize_t elv_iosched_show(struct request_queue *, char *);
149extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
Jens Axboe165125e2007-07-24 09:28:11 +0200151extern int elevator_init(struct request_queue *, char *);
Jens Axboeb374d182008-10-31 10:05:07 +0100152extern void elevator_exit(struct elevator_queue *);
Jens Axboe5dd531a2010-08-23 13:52:19 +0200153extern int elevator_change(struct request_queue *, const char *);
Tejun Heo050c8ea2012-02-08 09:19:38 +0100154extern bool elv_rq_merge_ok(struct request *, struct bio *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
156/*
Jens Axboe2e662b62006-07-13 11:55:04 +0200157 * Helper functions.
158 */
Jens Axboe165125e2007-07-24 09:28:11 +0200159extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
160extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200161
162/*
163 * rb support functions.
164 */
Jeff Moyer796d5112011-06-02 21:19:05 +0200165extern void elv_rb_add(struct rb_root *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200166extern void elv_rb_del(struct rb_root *, struct request *);
167extern struct request *elv_rb_find(struct rb_root *, sector_t);
168
169/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 * Return values from elevator merger
171 */
172#define ELEVATOR_NO_MERGE 0
173#define ELEVATOR_FRONT_MERGE 1
174#define ELEVATOR_BACK_MERGE 2
175
176/*
177 * Insertion selection
178 */
179#define ELEVATOR_INSERT_FRONT 1
180#define ELEVATOR_INSERT_BACK 2
181#define ELEVATOR_INSERT_SORT 3
Tejun Heo797e7db2006-01-06 09:51:03 +0100182#define ELEVATOR_INSERT_REQUEUE 4
Tejun Heoae1b1532011-01-25 12:43:54 +0100183#define ELEVATOR_INSERT_FLUSH 5
Jens Axboe5e84ea32011-03-21 10:14:27 +0100184#define ELEVATOR_INSERT_SORT_MERGE 6
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
186/*
187 * return values from elevator_may_queue_fn
188 */
189enum {
190 ELV_MQUEUE_MAY,
191 ELV_MQUEUE_NO,
192 ELV_MQUEUE_MUST,
193};
194
Tejun Heo2e46e8b2009-05-07 22:24:41 +0900195#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
Jens Axboe2e662b62006-07-13 11:55:04 +0200196#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
Jens Axboe1b47f532005-10-20 16:37:00 +0200197
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200198/*
Jens Axboec7c22e42008-09-13 20:26:01 +0200199 * Hack to reuse the csd.list list_head as the fifo time holder while
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200200 * the request is in the io scheduler. Saves an unsigned long in rq.
201 */
Jens Axboec7c22e42008-09-13 20:26:01 +0200202#define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
203#define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200204#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
205#define rq_fifo_clear(rq) do { \
206 list_del_init(&(rq)->queuelist); \
Jens Axboec7c22e42008-09-13 20:26:01 +0200207 INIT_LIST_HEAD(&(rq)->csd.list); \
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200208 } while (0)
209
Tejun Heobb813f42013-01-18 14:05:56 -0800210#else /* CONFIG_BLOCK */
211
212static inline void load_default_elevator_module(void) { }
213
David Howells93614012006-09-30 20:45:40 +0200214#endif /* CONFIG_BLOCK */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215#endif