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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>
Sasha Levin242d98f2012-12-17 10:01:27 -05005#include <linux/hashtable.h>
Jens Axboe4a893e82006-07-22 15:37:43 +02006
David Howells93614012006-09-30 20:45:40 +02007#ifdef CONFIG_BLOCK
8
Tejun Heo7e5a8792011-12-14 00:33:42 +01009struct io_cq;
10
Jens Axboe165125e2007-07-24 09:28:11 +020011typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 struct bio *);
13
Jens Axboe165125e2007-07-24 09:28:11 +020014typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
Jens Axboe165125e2007-07-24 09:28:11 +020016typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
Jens Axboe165125e2007-07-24 09:28:11 +020018typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *);
Jens Axboeda775262006-12-20 11:04:12 +010019
Divyesh Shah812d4022010-04-08 21:14:23 -070020typedef void (elevator_bio_merged_fn) (struct request_queue *,
21 struct request *, struct bio *);
22
Jens Axboe165125e2007-07-24 09:28:11 +020023typedef int (elevator_dispatch_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
Jens Axboe165125e2007-07-24 09:28:11 +020025typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020026typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
27typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
28typedef int (elevator_may_queue_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
Tejun Heo9b84cac2011-12-14 00:33:42 +010030typedef void (elevator_init_icq_fn) (struct io_cq *);
Tejun Heo7e5a8792011-12-14 00:33:42 +010031typedef void (elevator_exit_icq_fn) (struct io_cq *);
Tejun Heo852c7882012-03-05 13:15:27 -080032typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
33 struct bio *, gfp_t);
Jens Axboebb37b942006-12-01 10:42:33 +010034typedef void (elevator_put_req_fn) (struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020035typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
36typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
Tejun Heob2fab5a2012-03-05 13:14:57 -080038typedef int (elevator_init_fn) (struct request_queue *);
Jens Axboeb374d182008-10-31 10:05:07 +010039typedef void (elevator_exit_fn) (struct elevator_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
41struct elevator_ops
42{
43 elevator_merge_fn *elevator_merge_fn;
44 elevator_merged_fn *elevator_merged_fn;
45 elevator_merge_req_fn *elevator_merge_req_fn;
Jens Axboeda775262006-12-20 11:04:12 +010046 elevator_allow_merge_fn *elevator_allow_merge_fn;
Divyesh Shah812d4022010-04-08 21:14:23 -070047 elevator_bio_merged_fn *elevator_bio_merged_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
Tejun Heo8922e162005-10-20 16:23:44 +020049 elevator_dispatch_fn *elevator_dispatch_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 elevator_add_req_fn *elevator_add_req_fn;
Tejun Heo8922e162005-10-20 16:23:44 +020051 elevator_activate_req_fn *elevator_activate_req_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
53
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 elevator_completed_req_fn *elevator_completed_req_fn;
55
56 elevator_request_list_fn *elevator_former_req_fn;
57 elevator_request_list_fn *elevator_latter_req_fn;
58
Tejun Heof1f8cc92011-12-14 00:33:42 +010059 elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
60 elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
Tejun Heo7e5a8792011-12-14 00:33:42 +010061
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 elevator_set_req_fn *elevator_set_req_fn;
63 elevator_put_req_fn *elevator_put_req_fn;
64
65 elevator_may_queue_fn *elevator_may_queue_fn;
66
67 elevator_init_fn *elevator_init_fn;
68 elevator_exit_fn *elevator_exit_fn;
69};
70
71#define ELV_NAME_MAX (16)
72
Al Viroe572ec72006-03-18 22:27:18 -050073struct elv_fs_entry {
74 struct attribute attr;
Jens Axboeb374d182008-10-31 10:05:07 +010075 ssize_t (*show)(struct elevator_queue *, char *);
76 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
Al Viroe572ec72006-03-18 22:27:18 -050077};
78
Linus Torvalds1da177e2005-04-16 15:20:36 -070079/*
80 * identifies an elevator type, such as AS or deadline
81 */
82struct elevator_type
83{
Tejun Heo3d3c2372011-12-14 00:33:42 +010084 /* managed by elevator core */
85 struct kmem_cache *icq_cache;
86
87 /* fields provided by elevator implementation */
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 struct elevator_ops ops;
Tejun Heof1f8cc92011-12-14 00:33:42 +010089 size_t icq_size; /* see iocontext.h */
90 size_t icq_align; /* ditto */
Al Viroe572ec72006-03-18 22:27:18 -050091 struct elv_fs_entry *elevator_attrs;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 char elevator_name[ELV_NAME_MAX];
93 struct module *elevator_owner;
Tejun Heo3d3c2372011-12-14 00:33:42 +010094
95 /* managed by elevator core */
96 char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
Tejun Heo22f746e2011-12-14 00:33:41 +010097 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098};
99
Sasha Levin242d98f2012-12-17 10:01:27 -0500100#define ELV_HASH_BITS 6
101
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102/*
Adrian Bunk54069582006-01-10 00:09:36 +0100103 * each queue has an elevator_queue associated with it
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 */
105struct elevator_queue
106{
Tejun Heo22f746e2011-12-14 00:33:41 +0100107 struct elevator_type *type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 void *elevator_data;
109 struct kobject kobj;
Al Viro3d1ab402006-03-18 18:35:43 -0500110 struct mutex sysfs_lock;
Jens Axboe430c62f2010-10-07 09:35:16 +0200111 unsigned int registered:1;
Sasha Levin242d98f2012-12-17 10:01:27 -0500112 DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113};
114
115/*
116 * block elevator interface
117 */
Jens Axboe165125e2007-07-24 09:28:11 +0200118extern void elv_dispatch_sort(struct request_queue *, struct request *);
119extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
Jens Axboe7eaceac2011-03-10 08:52:07 +0100120extern void elv_add_request(struct request_queue *, struct request *, int);
121extern void __elv_add_request(struct request_queue *, struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200122extern int elv_merge(struct request_queue *, struct request **, struct bio *);
123extern void elv_merge_requests(struct request_queue *, struct request *,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200125extern void elv_merged_request(struct request_queue *, struct request *, int);
Divyesh Shah812d4022010-04-08 21:14:23 -0700126extern void elv_bio_merged(struct request_queue *q, struct request *,
127 struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200128extern void elv_requeue_request(struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200129extern struct request *elv_former_request(struct request_queue *, struct request *);
130extern struct request *elv_latter_request(struct request_queue *, struct request *);
131extern int elv_register_queue(struct request_queue *q);
132extern void elv_unregister_queue(struct request_queue *q);
133extern int elv_may_queue(struct request_queue *, int);
Mike Anderson11914a52008-09-13 20:31:27 +0200134extern void elv_abort_queue(struct request_queue *);
Jens Axboe165125e2007-07-24 09:28:11 +0200135extern void elv_completed_request(struct request_queue *, struct request *);
Tejun Heo852c7882012-03-05 13:15:27 -0800136extern int elv_set_request(struct request_queue *q, struct request *rq,
137 struct bio *bio, gfp_t gfp_mask);
Jens Axboe165125e2007-07-24 09:28:11 +0200138extern void elv_put_request(struct request_queue *, struct request *);
Jerome Marchand26308ea2009-03-27 10:31:51 +0100139extern void elv_drain_elevator(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140
141/*
142 * io scheduler registration
143 */
Tejun Heobb813f42013-01-18 14:05:56 -0800144extern void __init load_default_elevator_module(void);
Tejun Heo3d3c2372011-12-14 00:33:42 +0100145extern int elv_register(struct elevator_type *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146extern void elv_unregister(struct elevator_type *);
147
148/*
149 * io scheduler sysfs switching
150 */
Jens Axboe165125e2007-07-24 09:28:11 +0200151extern ssize_t elv_iosched_show(struct request_queue *, char *);
152extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
Jens Axboe165125e2007-07-24 09:28:11 +0200154extern int elevator_init(struct request_queue *, char *);
Jens Axboeb374d182008-10-31 10:05:07 +0100155extern void elevator_exit(struct elevator_queue *);
Jens Axboe5dd531a2010-08-23 13:52:19 +0200156extern int elevator_change(struct request_queue *, const char *);
Tejun Heo050c8ea2012-02-08 09:19:38 +0100157extern bool elv_rq_merge_ok(struct request *, struct bio *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
159/*
Jens Axboe2e662b62006-07-13 11:55:04 +0200160 * Helper functions.
161 */
Jens Axboe165125e2007-07-24 09:28:11 +0200162extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
163extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200164
165/*
166 * rb support functions.
167 */
Jeff Moyer796d5112011-06-02 21:19:05 +0200168extern void elv_rb_add(struct rb_root *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200169extern void elv_rb_del(struct rb_root *, struct request *);
170extern struct request *elv_rb_find(struct rb_root *, sector_t);
171
172/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 * Return values from elevator merger
174 */
175#define ELEVATOR_NO_MERGE 0
176#define ELEVATOR_FRONT_MERGE 1
177#define ELEVATOR_BACK_MERGE 2
178
179/*
180 * Insertion selection
181 */
182#define ELEVATOR_INSERT_FRONT 1
183#define ELEVATOR_INSERT_BACK 2
184#define ELEVATOR_INSERT_SORT 3
Tejun Heo797e7db2006-01-06 09:51:03 +0100185#define ELEVATOR_INSERT_REQUEUE 4
Tejun Heoae1b1532011-01-25 12:43:54 +0100186#define ELEVATOR_INSERT_FLUSH 5
Jens Axboe5e84ea32011-03-21 10:14:27 +0100187#define ELEVATOR_INSERT_SORT_MERGE 6
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188
189/*
190 * return values from elevator_may_queue_fn
191 */
192enum {
193 ELV_MQUEUE_MAY,
194 ELV_MQUEUE_NO,
195 ELV_MQUEUE_MUST,
196};
197
Tejun Heo2e46e8b2009-05-07 22:24:41 +0900198#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
Jens Axboe2e662b62006-07-13 11:55:04 +0200199#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
Jens Axboe1b47f532005-10-20 16:37:00 +0200200
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200201/*
Jens Axboec7c22e42008-09-13 20:26:01 +0200202 * Hack to reuse the csd.list list_head as the fifo time holder while
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200203 * the request is in the io scheduler. Saves an unsigned long in rq.
204 */
Jens Axboec7c22e42008-09-13 20:26:01 +0200205#define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
206#define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200207#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
208#define rq_fifo_clear(rq) do { \
209 list_del_init(&(rq)->queuelist); \
Jens Axboec7c22e42008-09-13 20:26:01 +0200210 INIT_LIST_HEAD(&(rq)->csd.list); \
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200211 } while (0)
212
Tejun Heobb813f42013-01-18 14:05:56 -0800213#else /* CONFIG_BLOCK */
214
215static inline void load_default_elevator_module(void) { }
216
David Howells93614012006-09-30 20:45:40 +0200217#endif /* CONFIG_BLOCK */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218#endif