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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;
Jianpeng Mad50235b2013-07-03 13:25:24 +020010struct elevator_type;
Tejun Heo7e5a8792011-12-14 00:33:42 +010011
Jens Axboe165125e2007-07-24 09:28:11 +020012typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 struct bio *);
14
Jens Axboe165125e2007-07-24 09:28:11 +020015typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070016
Jens Axboe165125e2007-07-24 09:28:11 +020017typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
Jens Axboe165125e2007-07-24 09:28:11 +020019typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *);
Jens Axboeda775262006-12-20 11:04:12 +010020
Divyesh Shah812d4022010-04-08 21:14:23 -070021typedef void (elevator_bio_merged_fn) (struct request_queue *,
22 struct request *, struct bio *);
23
Jens Axboe165125e2007-07-24 09:28:11 +020024typedef int (elevator_dispatch_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
Jens Axboe165125e2007-07-24 09:28:11 +020026typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020027typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
28typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
29typedef int (elevator_may_queue_fn) (struct request_queue *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
Tejun Heo9b84cac2011-12-14 00:33:42 +010031typedef void (elevator_init_icq_fn) (struct io_cq *);
Tejun Heo7e5a8792011-12-14 00:33:42 +010032typedef void (elevator_exit_icq_fn) (struct io_cq *);
Tejun Heo852c7882012-03-05 13:15:27 -080033typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
34 struct bio *, gfp_t);
Jens Axboebb37b942006-12-01 10:42:33 +010035typedef void (elevator_put_req_fn) (struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +020036typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
37typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
Jianpeng Mad50235b2013-07-03 13:25:24 +020039typedef int (elevator_init_fn) (struct request_queue *,
40 struct elevator_type *e);
Jens Axboeb374d182008-10-31 10:05:07 +010041typedef void (elevator_exit_fn) (struct elevator_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43struct elevator_ops
44{
45 elevator_merge_fn *elevator_merge_fn;
46 elevator_merged_fn *elevator_merged_fn;
47 elevator_merge_req_fn *elevator_merge_req_fn;
Jens Axboeda775262006-12-20 11:04:12 +010048 elevator_allow_merge_fn *elevator_allow_merge_fn;
Divyesh Shah812d4022010-04-08 21:14:23 -070049 elevator_bio_merged_fn *elevator_bio_merged_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
Tejun Heo8922e162005-10-20 16:23:44 +020051 elevator_dispatch_fn *elevator_dispatch_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 elevator_add_req_fn *elevator_add_req_fn;
Tejun Heo8922e162005-10-20 16:23:44 +020053 elevator_activate_req_fn *elevator_activate_req_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 elevator_completed_req_fn *elevator_completed_req_fn;
57
58 elevator_request_list_fn *elevator_former_req_fn;
59 elevator_request_list_fn *elevator_latter_req_fn;
60
Tejun Heof1f8cc92011-12-14 00:33:42 +010061 elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
62 elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
Tejun Heo7e5a8792011-12-14 00:33:42 +010063
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 elevator_set_req_fn *elevator_set_req_fn;
65 elevator_put_req_fn *elevator_put_req_fn;
66
67 elevator_may_queue_fn *elevator_may_queue_fn;
68
69 elevator_init_fn *elevator_init_fn;
70 elevator_exit_fn *elevator_exit_fn;
71};
72
73#define ELV_NAME_MAX (16)
74
Al Viroe572ec72006-03-18 22:27:18 -050075struct elv_fs_entry {
76 struct attribute attr;
Jens Axboeb374d182008-10-31 10:05:07 +010077 ssize_t (*show)(struct elevator_queue *, char *);
78 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
Al Viroe572ec72006-03-18 22:27:18 -050079};
80
Linus Torvalds1da177e2005-04-16 15:20:36 -070081/*
82 * identifies an elevator type, such as AS or deadline
83 */
84struct elevator_type
85{
Tejun Heo3d3c2372011-12-14 00:33:42 +010086 /* managed by elevator core */
87 struct kmem_cache *icq_cache;
88
89 /* fields provided by elevator implementation */
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 struct elevator_ops ops;
Tejun Heof1f8cc92011-12-14 00:33:42 +010091 size_t icq_size; /* see iocontext.h */
92 size_t icq_align; /* ditto */
Al Viroe572ec72006-03-18 22:27:18 -050093 struct elv_fs_entry *elevator_attrs;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 char elevator_name[ELV_NAME_MAX];
95 struct module *elevator_owner;
Tejun Heo3d3c2372011-12-14 00:33:42 +010096
97 /* managed by elevator core */
98 char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
Tejun Heo22f746e2011-12-14 00:33:41 +010099 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100};
101
Sasha Levin242d98f2012-12-17 10:01:27 -0500102#define ELV_HASH_BITS 6
103
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104/*
Adrian Bunk54069582006-01-10 00:09:36 +0100105 * each queue has an elevator_queue associated with it
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 */
107struct elevator_queue
108{
Tejun Heo22f746e2011-12-14 00:33:41 +0100109 struct elevator_type *type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 void *elevator_data;
111 struct kobject kobj;
Al Viro3d1ab402006-03-18 18:35:43 -0500112 struct mutex sysfs_lock;
Jens Axboe430c62f2010-10-07 09:35:16 +0200113 unsigned int registered:1;
Sasha Levin242d98f2012-12-17 10:01:27 -0500114 DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115};
116
117/*
118 * block elevator interface
119 */
Jens Axboe165125e2007-07-24 09:28:11 +0200120extern void elv_dispatch_sort(struct request_queue *, struct request *);
121extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
Jens Axboe7eaceac2011-03-10 08:52:07 +0100122extern void elv_add_request(struct request_queue *, struct request *, int);
123extern void __elv_add_request(struct request_queue *, struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200124extern int elv_merge(struct request_queue *, struct request **, struct bio *);
125extern void elv_merge_requests(struct request_queue *, struct request *,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200127extern void elv_merged_request(struct request_queue *, struct request *, int);
Divyesh Shah812d4022010-04-08 21:14:23 -0700128extern void elv_bio_merged(struct request_queue *q, struct request *,
129 struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200130extern void elv_requeue_request(struct request_queue *, struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200131extern struct request *elv_former_request(struct request_queue *, struct request *);
132extern struct request *elv_latter_request(struct request_queue *, struct request *);
133extern int elv_register_queue(struct request_queue *q);
134extern void elv_unregister_queue(struct request_queue *q);
135extern int elv_may_queue(struct request_queue *, int);
136extern void elv_completed_request(struct request_queue *, struct request *);
Tejun Heo852c7882012-03-05 13:15:27 -0800137extern int elv_set_request(struct request_queue *q, struct request *rq,
138 struct bio *bio, gfp_t gfp_mask);
Jens Axboe165125e2007-07-24 09:28:11 +0200139extern void elv_put_request(struct request_queue *, struct request *);
Jerome Marchand26308ea2009-03-27 10:31:51 +0100140extern void elv_drain_elevator(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
142/*
143 * io scheduler registration
144 */
Tejun Heobb813f42013-01-18 14:05:56 -0800145extern void __init load_default_elevator_module(void);
Jens Axboee567bf72014-06-22 16:32:48 -0600146extern int elv_register(struct elevator_type *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147extern void elv_unregister(struct elevator_type *);
148
149/*
150 * io scheduler sysfs switching
151 */
Jens Axboe165125e2007-07-24 09:28:11 +0200152extern ssize_t elv_iosched_show(struct request_queue *, char *);
153extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154
Jens Axboe165125e2007-07-24 09:28:11 +0200155extern int elevator_init(struct request_queue *, char *);
Jens Axboeb374d182008-10-31 10:05:07 +0100156extern void elevator_exit(struct elevator_queue *);
Jens Axboe5dd531a2010-08-23 13:52:19 +0200157extern int elevator_change(struct request_queue *, const char *);
Tejun Heo050c8ea2012-02-08 09:19:38 +0100158extern bool elv_rq_merge_ok(struct request *, struct bio *);
Jianpeng Mad50235b2013-07-03 13:25:24 +0200159extern struct elevator_queue *elevator_alloc(struct request_queue *,
160 struct elevator_type *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
162/*
Jens Axboe2e662b62006-07-13 11:55:04 +0200163 * Helper functions.
164 */
Jens Axboe165125e2007-07-24 09:28:11 +0200165extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
166extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200167
168/*
169 * rb support functions.
170 */
Jeff Moyer796d5112011-06-02 21:19:05 +0200171extern void elv_rb_add(struct rb_root *, struct request *);
Jens Axboe2e662b62006-07-13 11:55:04 +0200172extern void elv_rb_del(struct rb_root *, struct request *);
173extern struct request *elv_rb_find(struct rb_root *, sector_t);
174
175/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 * Return values from elevator merger
177 */
178#define ELEVATOR_NO_MERGE 0
179#define ELEVATOR_FRONT_MERGE 1
180#define ELEVATOR_BACK_MERGE 2
181
182/*
183 * Insertion selection
184 */
185#define ELEVATOR_INSERT_FRONT 1
186#define ELEVATOR_INSERT_BACK 2
187#define ELEVATOR_INSERT_SORT 3
Tejun Heo797e7db2006-01-06 09:51:03 +0100188#define ELEVATOR_INSERT_REQUEUE 4
Tejun Heoae1b1532011-01-25 12:43:54 +0100189#define ELEVATOR_INSERT_FLUSH 5
Jens Axboe5e84ea32011-03-21 10:14:27 +0100190#define ELEVATOR_INSERT_SORT_MERGE 6
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191
192/*
193 * return values from elevator_may_queue_fn
194 */
195enum {
196 ELV_MQUEUE_MAY,
197 ELV_MQUEUE_NO,
198 ELV_MQUEUE_MUST,
199};
200
Tejun Heo2e46e8b2009-05-07 22:24:41 +0900201#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
Jens Axboe2e662b62006-07-13 11:55:04 +0200202#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
Jens Axboe1b47f532005-10-20 16:37:00 +0200203
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200204#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
Frederic Weisbeckerd9a74df2014-02-24 16:39:53 +0100205#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
Jens Axboe1fbfdfc2006-07-11 21:49:15 +0200206
Tejun Heobb813f42013-01-18 14:05:56 -0800207#else /* CONFIG_BLOCK */
208
209static inline void load_default_elevator_module(void) { }
210
David Howells93614012006-09-30 20:45:40 +0200211#endif /* CONFIG_BLOCK */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212#endif