1 #ifndef _LINUX_ELEVATOR_H
2 #define _LINUX_ELEVATOR_H
4 #include <linux/percpu.h>
5 #include <linux/hashtable.h>
12 typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
15 typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
17 typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int);
19 typedef int (elevator_allow_bio_merge_fn) (struct request_queue *,
20 struct request *, struct bio *);
22 typedef int (elevator_allow_rq_merge_fn) (struct request_queue *,
23 struct request *, struct request *);
25 typedef void (elevator_bio_merged_fn) (struct request_queue *,
26 struct request *, struct bio *);
28 typedef int (elevator_dispatch_fn) (struct request_queue *, int);
30 typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
31 typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
32 typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
33 typedef int (elevator_may_queue_fn) (struct request_queue *, unsigned int);
35 typedef void (elevator_init_icq_fn) (struct io_cq *);
36 typedef void (elevator_exit_icq_fn) (struct io_cq *);
37 typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
39 typedef void (elevator_put_req_fn) (struct request *);
40 typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
41 typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
43 typedef int (elevator_init_fn) (struct request_queue *,
44 struct elevator_type *e);
45 typedef void (elevator_exit_fn) (struct elevator_queue *);
46 typedef void (elevator_registered_fn) (struct request_queue *);
50 elevator_merge_fn *elevator_merge_fn;
51 elevator_merged_fn *elevator_merged_fn;
52 elevator_merge_req_fn *elevator_merge_req_fn;
53 elevator_allow_bio_merge_fn *elevator_allow_bio_merge_fn;
54 elevator_allow_rq_merge_fn *elevator_allow_rq_merge_fn;
55 elevator_bio_merged_fn *elevator_bio_merged_fn;
57 elevator_dispatch_fn *elevator_dispatch_fn;
58 elevator_add_req_fn *elevator_add_req_fn;
59 elevator_activate_req_fn *elevator_activate_req_fn;
60 elevator_deactivate_req_fn *elevator_deactivate_req_fn;
62 elevator_completed_req_fn *elevator_completed_req_fn;
64 elevator_request_list_fn *elevator_former_req_fn;
65 elevator_request_list_fn *elevator_latter_req_fn;
67 elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
68 elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
70 elevator_set_req_fn *elevator_set_req_fn;
71 elevator_put_req_fn *elevator_put_req_fn;
73 elevator_may_queue_fn *elevator_may_queue_fn;
75 elevator_init_fn *elevator_init_fn;
76 elevator_exit_fn *elevator_exit_fn;
77 elevator_registered_fn *elevator_registered_fn;
80 struct blk_mq_alloc_data;
83 struct elevator_mq_ops {
84 int (*init_sched)(struct request_queue *, struct elevator_type *);
85 void (*exit_sched)(struct elevator_queue *);
87 bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);
88 bool (*bio_merge)(struct blk_mq_hw_ctx *, struct bio *);
89 int (*request_merge)(struct request_queue *q, struct request **, struct bio *);
90 void (*request_merged)(struct request_queue *, struct request *, int);
91 void (*requests_merged)(struct request_queue *, struct request *, struct request *);
92 struct request *(*get_request)(struct request_queue *, unsigned int, struct blk_mq_alloc_data *);
93 void (*put_request)(struct request *);
94 void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool);
95 void (*dispatch_requests)(struct blk_mq_hw_ctx *, struct list_head *);
96 bool (*has_work)(struct blk_mq_hw_ctx *);
97 void (*completed_request)(struct blk_mq_hw_ctx *, struct request *);
98 void (*started_request)(struct request *);
99 void (*requeue_request)(struct request *);
100 struct request *(*former_request)(struct request_queue *, struct request *);
101 struct request *(*next_request)(struct request_queue *, struct request *);
102 int (*get_rq_priv)(struct request_queue *, struct request *);
103 void (*put_rq_priv)(struct request_queue *, struct request *);
104 void (*init_icq)(struct io_cq *);
105 void (*exit_icq)(struct io_cq *);
108 #define ELV_NAME_MAX (16)
110 struct elv_fs_entry {
111 struct attribute attr;
112 ssize_t (*show)(struct elevator_queue *, char *);
113 ssize_t (*store)(struct elevator_queue *, const char *, size_t);
117 * identifies an elevator type, such as AS or deadline
121 /* managed by elevator core */
122 struct kmem_cache *icq_cache;
124 /* fields provided by elevator implementation */
126 struct elevator_ops sq;
127 struct elevator_mq_ops mq;
129 size_t icq_size; /* see iocontext.h */
130 size_t icq_align; /* ditto */
131 struct elv_fs_entry *elevator_attrs;
132 char elevator_name[ELV_NAME_MAX];
133 struct module *elevator_owner;
136 /* managed by elevator core */
137 char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
138 struct list_head list;
141 #define ELV_HASH_BITS 6
143 void elv_rqhash_del(struct request_queue *q, struct request *rq);
144 void elv_rqhash_add(struct request_queue *q, struct request *rq);
145 void elv_rqhash_reposition(struct request_queue *q, struct request *rq);
146 struct request *elv_rqhash_find(struct request_queue *q, sector_t offset);
149 * each queue has an elevator_queue associated with it
151 struct elevator_queue
153 struct elevator_type *type;
156 struct mutex sysfs_lock;
157 unsigned int registered:1;
158 unsigned int uses_mq:1;
159 DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
163 * block elevator interface
165 extern void elv_dispatch_sort(struct request_queue *, struct request *);
166 extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
167 extern void elv_add_request(struct request_queue *, struct request *, int);
168 extern void __elv_add_request(struct request_queue *, struct request *, int);
169 extern int elv_merge(struct request_queue *, struct request **, struct bio *);
170 extern void elv_merge_requests(struct request_queue *, struct request *,
172 extern void elv_merged_request(struct request_queue *, struct request *, int);
173 extern void elv_bio_merged(struct request_queue *q, struct request *,
175 extern bool elv_attempt_insert_merge(struct request_queue *, struct request *);
176 extern void elv_requeue_request(struct request_queue *, struct request *);
177 extern struct request *elv_former_request(struct request_queue *, struct request *);
178 extern struct request *elv_latter_request(struct request_queue *, struct request *);
179 extern int elv_register_queue(struct request_queue *q);
180 extern void elv_unregister_queue(struct request_queue *q);
181 extern int elv_may_queue(struct request_queue *, unsigned int);
182 extern void elv_completed_request(struct request_queue *, struct request *);
183 extern int elv_set_request(struct request_queue *q, struct request *rq,
184 struct bio *bio, gfp_t gfp_mask);
185 extern void elv_put_request(struct request_queue *, struct request *);
186 extern void elv_drain_elevator(struct request_queue *);
189 * io scheduler registration
191 extern void __init load_default_elevator_module(void);
192 extern int elv_register(struct elevator_type *);
193 extern void elv_unregister(struct elevator_type *);
196 * io scheduler sysfs switching
198 extern ssize_t elv_iosched_show(struct request_queue *, char *);
199 extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
201 extern int elevator_init(struct request_queue *, char *);
202 extern void elevator_exit(struct elevator_queue *);
203 extern int elevator_change(struct request_queue *, const char *);
204 extern bool elv_bio_merge_ok(struct request *, struct bio *);
205 extern struct elevator_queue *elevator_alloc(struct request_queue *,
206 struct elevator_type *);
211 extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
212 extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
215 * rb support functions.
217 extern void elv_rb_add(struct rb_root *, struct request *);
218 extern void elv_rb_del(struct rb_root *, struct request *);
219 extern struct request *elv_rb_find(struct rb_root *, sector_t);
222 * Return values from elevator merger
224 #define ELEVATOR_NO_MERGE 0
225 #define ELEVATOR_FRONT_MERGE 1
226 #define ELEVATOR_BACK_MERGE 2
229 * Insertion selection
231 #define ELEVATOR_INSERT_FRONT 1
232 #define ELEVATOR_INSERT_BACK 2
233 #define ELEVATOR_INSERT_SORT 3
234 #define ELEVATOR_INSERT_REQUEUE 4
235 #define ELEVATOR_INSERT_FLUSH 5
236 #define ELEVATOR_INSERT_SORT_MERGE 6
239 * return values from elevator_may_queue_fn
247 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
248 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
250 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
251 #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
253 #else /* CONFIG_BLOCK */
255 static inline void load_default_elevator_module(void) { }
257 #endif /* CONFIG_BLOCK */