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1da177e4 LT |
1 | #ifndef _LINUX_ELEVATOR_H |
2 | #define _LINUX_ELEVATOR_H | |
3 | ||
4a893e83 | 4 | #include <linux/percpu.h> |
242d98f0 | 5 | #include <linux/hashtable.h> |
4a893e83 | 6 | |
9361401e DH |
7 | #ifdef CONFIG_BLOCK |
8 | ||
7e5a8794 TH |
9 | struct io_cq; |
10 | ||
165125e1 | 11 | typedef int (elevator_merge_fn) (struct request_queue *, struct request **, |
1da177e4 LT |
12 | struct bio *); |
13 | ||
165125e1 | 14 | typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); |
1da177e4 | 15 | |
165125e1 | 16 | typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); |
1da177e4 | 17 | |
165125e1 | 18 | typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *); |
da775265 | 19 | |
812d4026 DS |
20 | typedef void (elevator_bio_merged_fn) (struct request_queue *, |
21 | struct request *, struct bio *); | |
22 | ||
165125e1 | 23 | typedef int (elevator_dispatch_fn) (struct request_queue *, int); |
1da177e4 | 24 | |
165125e1 | 25 | typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); |
165125e1 JA |
26 | typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *); |
27 | typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *); | |
28 | typedef int (elevator_may_queue_fn) (struct request_queue *, int); | |
1da177e4 | 29 | |
9b84cacd | 30 | typedef void (elevator_init_icq_fn) (struct io_cq *); |
7e5a8794 | 31 | typedef void (elevator_exit_icq_fn) (struct io_cq *); |
852c788f TH |
32 | typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, |
33 | struct bio *, gfp_t); | |
bb37b94c | 34 | typedef void (elevator_put_req_fn) (struct request *); |
165125e1 JA |
35 | typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); |
36 | typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); | |
1da177e4 | 37 | |
b2fab5ac | 38 | typedef int (elevator_init_fn) (struct request_queue *); |
b374d18a | 39 | typedef void (elevator_exit_fn) (struct elevator_queue *); |
1da177e4 LT |
40 | |
41 | struct 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; | |
da775265 | 46 | elevator_allow_merge_fn *elevator_allow_merge_fn; |
812d4026 | 47 | elevator_bio_merged_fn *elevator_bio_merged_fn; |
1da177e4 | 48 | |
8922e16c | 49 | elevator_dispatch_fn *elevator_dispatch_fn; |
1da177e4 | 50 | elevator_add_req_fn *elevator_add_req_fn; |
8922e16c | 51 | elevator_activate_req_fn *elevator_activate_req_fn; |
1da177e4 LT |
52 | elevator_deactivate_req_fn *elevator_deactivate_req_fn; |
53 | ||
1da177e4 LT |
54 | 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 | ||
f1f8cc94 TH |
59 | elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */ |
60 | elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */ | |
7e5a8794 | 61 | |
1da177e4 LT |
62 | 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 | ||
e572ec7e AV |
73 | struct elv_fs_entry { |
74 | struct attribute attr; | |
b374d18a JA |
75 | ssize_t (*show)(struct elevator_queue *, char *); |
76 | ssize_t (*store)(struct elevator_queue *, const char *, size_t); | |
e572ec7e AV |
77 | }; |
78 | ||
1da177e4 LT |
79 | /* |
80 | * identifies an elevator type, such as AS or deadline | |
81 | */ | |
82 | struct elevator_type | |
83 | { | |
3d3c2379 TH |
84 | /* managed by elevator core */ |
85 | struct kmem_cache *icq_cache; | |
86 | ||
87 | /* fields provided by elevator implementation */ | |
1da177e4 | 88 | struct elevator_ops ops; |
f1f8cc94 TH |
89 | size_t icq_size; /* see iocontext.h */ |
90 | size_t icq_align; /* ditto */ | |
e572ec7e | 91 | struct elv_fs_entry *elevator_attrs; |
1da177e4 LT |
92 | char elevator_name[ELV_NAME_MAX]; |
93 | struct module *elevator_owner; | |
3d3c2379 TH |
94 | |
95 | /* managed by elevator core */ | |
96 | char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */ | |
22f746e2 | 97 | struct list_head list; |
1da177e4 LT |
98 | }; |
99 | ||
242d98f0 SL |
100 | #define ELV_HASH_BITS 6 |
101 | ||
1da177e4 | 102 | /* |
54069588 | 103 | * each queue has an elevator_queue associated with it |
1da177e4 LT |
104 | */ |
105 | struct elevator_queue | |
106 | { | |
22f746e2 | 107 | struct elevator_type *type; |
1da177e4 LT |
108 | void *elevator_data; |
109 | struct kobject kobj; | |
3d1ab40f | 110 | struct mutex sysfs_lock; |
430c62fb | 111 | unsigned int registered:1; |
242d98f0 | 112 | DECLARE_HASHTABLE(hash, ELV_HASH_BITS); |
1da177e4 LT |
113 | }; |
114 | ||
115 | /* | |
116 | * block elevator interface | |
117 | */ | |
165125e1 JA |
118 | extern void elv_dispatch_sort(struct request_queue *, struct request *); |
119 | extern void elv_dispatch_add_tail(struct request_queue *, struct request *); | |
7eaceacc JA |
120 | extern void elv_add_request(struct request_queue *, struct request *, int); |
121 | extern void __elv_add_request(struct request_queue *, struct request *, int); | |
165125e1 JA |
122 | extern int elv_merge(struct request_queue *, struct request **, struct bio *); |
123 | extern void elv_merge_requests(struct request_queue *, struct request *, | |
1da177e4 | 124 | struct request *); |
165125e1 | 125 | extern void elv_merged_request(struct request_queue *, struct request *, int); |
812d4026 DS |
126 | extern void elv_bio_merged(struct request_queue *q, struct request *, |
127 | struct bio *); | |
165125e1 | 128 | extern void elv_requeue_request(struct request_queue *, struct request *); |
165125e1 JA |
129 | extern struct request *elv_former_request(struct request_queue *, struct request *); |
130 | extern struct request *elv_latter_request(struct request_queue *, struct request *); | |
131 | extern int elv_register_queue(struct request_queue *q); | |
132 | extern void elv_unregister_queue(struct request_queue *q); | |
133 | extern int elv_may_queue(struct request_queue *, int); | |
11914a53 | 134 | extern void elv_abort_queue(struct request_queue *); |
165125e1 | 135 | extern void elv_completed_request(struct request_queue *, struct request *); |
852c788f TH |
136 | extern int elv_set_request(struct request_queue *q, struct request *rq, |
137 | struct bio *bio, gfp_t gfp_mask); | |
165125e1 | 138 | extern void elv_put_request(struct request_queue *, struct request *); |
26308eab | 139 | extern void elv_drain_elevator(struct request_queue *); |
1da177e4 LT |
140 | |
141 | /* | |
142 | * io scheduler registration | |
143 | */ | |
bb813f4c | 144 | extern void __init load_default_elevator_module(void); |
3d3c2379 | 145 | extern int elv_register(struct elevator_type *); |
1da177e4 LT |
146 | extern void elv_unregister(struct elevator_type *); |
147 | ||
148 | /* | |
149 | * io scheduler sysfs switching | |
150 | */ | |
165125e1 JA |
151 | extern ssize_t elv_iosched_show(struct request_queue *, char *); |
152 | extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); | |
1da177e4 | 153 | |
165125e1 | 154 | extern int elevator_init(struct request_queue *, char *); |
b374d18a | 155 | extern void elevator_exit(struct elevator_queue *); |
5dd531a0 | 156 | extern int elevator_change(struct request_queue *, const char *); |
050c8ea8 | 157 | extern bool elv_rq_merge_ok(struct request *, struct bio *); |
1da177e4 | 158 | |
2e662b65 JA |
159 | /* |
160 | * Helper functions. | |
161 | */ | |
165125e1 JA |
162 | extern struct request *elv_rb_former_request(struct request_queue *, struct request *); |
163 | extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); | |
2e662b65 JA |
164 | |
165 | /* | |
166 | * rb support functions. | |
167 | */ | |
796d5116 | 168 | extern void elv_rb_add(struct rb_root *, struct request *); |
2e662b65 JA |
169 | extern void elv_rb_del(struct rb_root *, struct request *); |
170 | extern struct request *elv_rb_find(struct rb_root *, sector_t); | |
171 | ||
1da177e4 LT |
172 | /* |
173 | * 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 | |
797e7dbb | 185 | #define ELEVATOR_INSERT_REQUEUE 4 |
ae1b1539 | 186 | #define ELEVATOR_INSERT_FLUSH 5 |
5e84ea3a | 187 | #define ELEVATOR_INSERT_SORT_MERGE 6 |
1da177e4 LT |
188 | |
189 | /* | |
190 | * return values from elevator_may_queue_fn | |
191 | */ | |
192 | enum { | |
193 | ELV_MQUEUE_MAY, | |
194 | ELV_MQUEUE_NO, | |
195 | ELV_MQUEUE_MUST, | |
196 | }; | |
197 | ||
2e46e8b2 | 198 | #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) |
2e662b65 | 199 | #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) |
1b47f531 | 200 | |
1fbfdfcd | 201 | /* |
c7c22e4d | 202 | * Hack to reuse the csd.list list_head as the fifo time holder while |
1fbfdfcd JA |
203 | * the request is in the io scheduler. Saves an unsigned long in rq. |
204 | */ | |
c7c22e4d JA |
205 | #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)) | |
1fbfdfcd JA |
207 | #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
208 | #define rq_fifo_clear(rq) do { \ | |
209 | list_del_init(&(rq)->queuelist); \ | |
c7c22e4d | 210 | INIT_LIST_HEAD(&(rq)->csd.list); \ |
1fbfdfcd JA |
211 | } while (0) |
212 | ||
bb813f4c TH |
213 | #else /* CONFIG_BLOCK */ |
214 | ||
215 | static inline void load_default_elevator_module(void) { } | |
216 | ||
9361401e | 217 | #endif /* CONFIG_BLOCK */ |
1da177e4 | 218 | #endif |