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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 | 9 | struct io_cq; |
d50235b7 | 10 | struct elevator_type; |
7e5a8794 | 11 | |
165125e1 | 12 | typedef int (elevator_merge_fn) (struct request_queue *, struct request **, |
1da177e4 LT |
13 | struct bio *); |
14 | ||
165125e1 | 15 | typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); |
1da177e4 | 16 | |
165125e1 | 17 | typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); |
1da177e4 | 18 | |
72ef799b TE |
19 | typedef int (elevator_allow_bio_merge_fn) (struct request_queue *, |
20 | struct request *, struct bio *); | |
21 | ||
22 | typedef int (elevator_allow_rq_merge_fn) (struct request_queue *, | |
23 | struct request *, struct request *); | |
da775265 | 24 | |
812d4026 DS |
25 | typedef void (elevator_bio_merged_fn) (struct request_queue *, |
26 | struct request *, struct bio *); | |
27 | ||
165125e1 | 28 | typedef int (elevator_dispatch_fn) (struct request_queue *, int); |
1da177e4 | 29 | |
165125e1 | 30 | typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); |
165125e1 JA |
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 *); | |
ba568ea0 | 33 | typedef int (elevator_may_queue_fn) (struct request_queue *, int, int); |
1da177e4 | 34 | |
9b84cacd | 35 | typedef void (elevator_init_icq_fn) (struct io_cq *); |
7e5a8794 | 36 | typedef void (elevator_exit_icq_fn) (struct io_cq *); |
852c788f TH |
37 | typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, |
38 | struct bio *, gfp_t); | |
bb37b94c | 39 | typedef void (elevator_put_req_fn) (struct request *); |
165125e1 JA |
40 | typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); |
41 | typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); | |
1da177e4 | 42 | |
d50235b7 JM |
43 | typedef int (elevator_init_fn) (struct request_queue *, |
44 | struct elevator_type *e); | |
b374d18a | 45 | typedef void (elevator_exit_fn) (struct elevator_queue *); |
0bb97947 | 46 | typedef void (elevator_registered_fn) (struct request_queue *); |
1da177e4 LT |
47 | |
48 | struct elevator_ops | |
49 | { | |
50 | elevator_merge_fn *elevator_merge_fn; | |
51 | elevator_merged_fn *elevator_merged_fn; | |
52 | elevator_merge_req_fn *elevator_merge_req_fn; | |
72ef799b TE |
53 | elevator_allow_bio_merge_fn *elevator_allow_bio_merge_fn; |
54 | elevator_allow_rq_merge_fn *elevator_allow_rq_merge_fn; | |
812d4026 | 55 | elevator_bio_merged_fn *elevator_bio_merged_fn; |
1da177e4 | 56 | |
8922e16c | 57 | elevator_dispatch_fn *elevator_dispatch_fn; |
1da177e4 | 58 | elevator_add_req_fn *elevator_add_req_fn; |
8922e16c | 59 | elevator_activate_req_fn *elevator_activate_req_fn; |
1da177e4 LT |
60 | elevator_deactivate_req_fn *elevator_deactivate_req_fn; |
61 | ||
1da177e4 LT |
62 | elevator_completed_req_fn *elevator_completed_req_fn; |
63 | ||
64 | elevator_request_list_fn *elevator_former_req_fn; | |
65 | elevator_request_list_fn *elevator_latter_req_fn; | |
66 | ||
f1f8cc94 TH |
67 | elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */ |
68 | elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */ | |
7e5a8794 | 69 | |
1da177e4 LT |
70 | elevator_set_req_fn *elevator_set_req_fn; |
71 | elevator_put_req_fn *elevator_put_req_fn; | |
72 | ||
73 | elevator_may_queue_fn *elevator_may_queue_fn; | |
74 | ||
75 | elevator_init_fn *elevator_init_fn; | |
76 | elevator_exit_fn *elevator_exit_fn; | |
0bb97947 | 77 | elevator_registered_fn *elevator_registered_fn; |
1da177e4 LT |
78 | }; |
79 | ||
80 | #define ELV_NAME_MAX (16) | |
81 | ||
e572ec7e AV |
82 | struct elv_fs_entry { |
83 | struct attribute attr; | |
b374d18a JA |
84 | ssize_t (*show)(struct elevator_queue *, char *); |
85 | ssize_t (*store)(struct elevator_queue *, const char *, size_t); | |
e572ec7e AV |
86 | }; |
87 | ||
1da177e4 LT |
88 | /* |
89 | * identifies an elevator type, such as AS or deadline | |
90 | */ | |
91 | struct elevator_type | |
92 | { | |
3d3c2379 TH |
93 | /* managed by elevator core */ |
94 | struct kmem_cache *icq_cache; | |
95 | ||
96 | /* fields provided by elevator implementation */ | |
1da177e4 | 97 | struct elevator_ops ops; |
f1f8cc94 TH |
98 | size_t icq_size; /* see iocontext.h */ |
99 | size_t icq_align; /* ditto */ | |
e572ec7e | 100 | struct elv_fs_entry *elevator_attrs; |
1da177e4 LT |
101 | char elevator_name[ELV_NAME_MAX]; |
102 | struct module *elevator_owner; | |
3d3c2379 TH |
103 | |
104 | /* managed by elevator core */ | |
105 | char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */ | |
22f746e2 | 106 | struct list_head list; |
1da177e4 LT |
107 | }; |
108 | ||
242d98f0 SL |
109 | #define ELV_HASH_BITS 6 |
110 | ||
1da177e4 | 111 | /* |
54069588 | 112 | * each queue has an elevator_queue associated with it |
1da177e4 LT |
113 | */ |
114 | struct elevator_queue | |
115 | { | |
22f746e2 | 116 | struct elevator_type *type; |
1da177e4 LT |
117 | void *elevator_data; |
118 | struct kobject kobj; | |
3d1ab40f | 119 | struct mutex sysfs_lock; |
430c62fb | 120 | unsigned int registered:1; |
242d98f0 | 121 | DECLARE_HASHTABLE(hash, ELV_HASH_BITS); |
1da177e4 LT |
122 | }; |
123 | ||
124 | /* | |
125 | * block elevator interface | |
126 | */ | |
165125e1 JA |
127 | extern void elv_dispatch_sort(struct request_queue *, struct request *); |
128 | extern void elv_dispatch_add_tail(struct request_queue *, struct request *); | |
7eaceacc JA |
129 | extern void elv_add_request(struct request_queue *, struct request *, int); |
130 | extern void __elv_add_request(struct request_queue *, struct request *, int); | |
165125e1 JA |
131 | extern int elv_merge(struct request_queue *, struct request **, struct bio *); |
132 | extern void elv_merge_requests(struct request_queue *, struct request *, | |
1da177e4 | 133 | struct request *); |
165125e1 | 134 | extern void elv_merged_request(struct request_queue *, struct request *, int); |
812d4026 DS |
135 | extern void elv_bio_merged(struct request_queue *q, struct request *, |
136 | struct bio *); | |
165125e1 | 137 | extern void elv_requeue_request(struct request_queue *, struct request *); |
165125e1 JA |
138 | extern struct request *elv_former_request(struct request_queue *, struct request *); |
139 | extern struct request *elv_latter_request(struct request_queue *, struct request *); | |
140 | extern int elv_register_queue(struct request_queue *q); | |
141 | extern void elv_unregister_queue(struct request_queue *q); | |
ba568ea0 | 142 | extern int elv_may_queue(struct request_queue *, int, int); |
165125e1 | 143 | extern void elv_completed_request(struct request_queue *, struct request *); |
852c788f TH |
144 | extern int elv_set_request(struct request_queue *q, struct request *rq, |
145 | struct bio *bio, gfp_t gfp_mask); | |
165125e1 | 146 | extern void elv_put_request(struct request_queue *, struct request *); |
26308eab | 147 | extern void elv_drain_elevator(struct request_queue *); |
1da177e4 LT |
148 | |
149 | /* | |
150 | * io scheduler registration | |
151 | */ | |
bb813f4c | 152 | extern void __init load_default_elevator_module(void); |
e567bf71 | 153 | extern int elv_register(struct elevator_type *); |
1da177e4 LT |
154 | extern void elv_unregister(struct elevator_type *); |
155 | ||
156 | /* | |
157 | * io scheduler sysfs switching | |
158 | */ | |
165125e1 JA |
159 | extern ssize_t elv_iosched_show(struct request_queue *, char *); |
160 | extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); | |
1da177e4 | 161 | |
165125e1 | 162 | extern int elevator_init(struct request_queue *, char *); |
b374d18a | 163 | extern void elevator_exit(struct elevator_queue *); |
5dd531a0 | 164 | extern int elevator_change(struct request_queue *, const char *); |
72ef799b | 165 | extern bool elv_bio_merge_ok(struct request *, struct bio *); |
d50235b7 JM |
166 | extern struct elevator_queue *elevator_alloc(struct request_queue *, |
167 | struct elevator_type *); | |
1da177e4 | 168 | |
2e662b65 JA |
169 | /* |
170 | * Helper functions. | |
171 | */ | |
165125e1 JA |
172 | extern struct request *elv_rb_former_request(struct request_queue *, struct request *); |
173 | extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); | |
2e662b65 JA |
174 | |
175 | /* | |
176 | * rb support functions. | |
177 | */ | |
796d5116 | 178 | extern void elv_rb_add(struct rb_root *, struct request *); |
2e662b65 JA |
179 | extern void elv_rb_del(struct rb_root *, struct request *); |
180 | extern struct request *elv_rb_find(struct rb_root *, sector_t); | |
181 | ||
1da177e4 LT |
182 | /* |
183 | * Return values from elevator merger | |
184 | */ | |
185 | #define ELEVATOR_NO_MERGE 0 | |
186 | #define ELEVATOR_FRONT_MERGE 1 | |
187 | #define ELEVATOR_BACK_MERGE 2 | |
188 | ||
189 | /* | |
190 | * Insertion selection | |
191 | */ | |
192 | #define ELEVATOR_INSERT_FRONT 1 | |
193 | #define ELEVATOR_INSERT_BACK 2 | |
194 | #define ELEVATOR_INSERT_SORT 3 | |
797e7dbb | 195 | #define ELEVATOR_INSERT_REQUEUE 4 |
ae1b1539 | 196 | #define ELEVATOR_INSERT_FLUSH 5 |
5e84ea3a | 197 | #define ELEVATOR_INSERT_SORT_MERGE 6 |
1da177e4 LT |
198 | |
199 | /* | |
200 | * return values from elevator_may_queue_fn | |
201 | */ | |
202 | enum { | |
203 | ELV_MQUEUE_MAY, | |
204 | ELV_MQUEUE_NO, | |
205 | ELV_MQUEUE_MUST, | |
206 | }; | |
207 | ||
2e46e8b2 | 208 | #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) |
2e662b65 | 209 | #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) |
1b47f531 | 210 | |
1fbfdfcd | 211 | #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
d9a74df5 | 212 | #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist) |
1fbfdfcd | 213 | |
bb813f4c TH |
214 | #else /* CONFIG_BLOCK */ |
215 | ||
216 | static inline void load_default_elevator_module(void) { } | |
217 | ||
9361401e | 218 | #endif /* CONFIG_BLOCK */ |
1da177e4 | 219 | #endif |