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1#ifndef BLK_INTERNAL_H
2#define BLK_INTERNAL_H
3
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4#include <linux/idr.h>
5
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6/* Amount of time in which a process may batch requests */
7#define BLK_BATCH_TIME (HZ/50UL)
8
9/* Number of requests a "batching" process may submit */
10#define BLK_BATCH_REQ 32
11
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12/* Max future timer expiry for timeouts */
13#define BLK_MAX_TIMEOUT (5 * HZ)
14
8324aa91 15extern struct kmem_cache *blk_requestq_cachep;
320ae51f 16extern struct kmem_cache *request_cachep;
8324aa91 17extern struct kobj_type blk_queue_ktype;
a73f730d 18extern struct ida blk_queue_ida;
8324aa91 19
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20static inline void __blk_get_queue(struct request_queue *q)
21{
22 kobject_get(&q->kobj);
23}
24
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25int blk_init_rl(struct request_list *rl, struct request_queue *q,
26 gfp_t gfp_mask);
27void blk_exit_rl(struct request_list *rl);
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28void init_request_from_bio(struct request *req, struct bio *bio);
29void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
30 struct bio *bio);
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31int blk_rq_append_bio(struct request_queue *q, struct request *rq,
32 struct bio *bio);
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33void blk_queue_bypass_start(struct request_queue *q);
34void blk_queue_bypass_end(struct request_queue *q);
9934c8c0 35void blk_dequeue_request(struct request *rq);
8324aa91 36void __blk_queue_free_tags(struct request_queue *q);
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37bool __blk_end_bidi_request(struct request *rq, int error,
38 unsigned int nr_bytes, unsigned int bidi_bytes);
8324aa91 39
242f9dcb 40void blk_rq_timed_out_timer(unsigned long data);
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41void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout,
42 unsigned int *next_set);
0d2602ca 43unsigned long blk_rq_timeout(unsigned long timeout);
87ee7b11 44void blk_add_timer(struct request *req);
242f9dcb 45void blk_delete_timer(struct request *);
242f9dcb 46
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47
48bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
49 struct bio *bio);
50bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
51 struct bio *bio);
52bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
53 unsigned int *request_count);
54
55void blk_account_io_start(struct request *req, bool new_io);
56void blk_account_io_completion(struct request *req, unsigned int bytes);
57void blk_account_io_done(struct request *req);
58
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59/*
60 * Internal atomic flags for request handling
61 */
62enum rq_atomic_flags {
63 REQ_ATOM_COMPLETE = 0,
320ae51f 64 REQ_ATOM_STARTED,
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65};
66
67/*
68 * EH timer and IO completion will both attempt to 'grab' the request, make
25985edc 69 * sure that only one of them succeeds
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70 */
71static inline int blk_mark_rq_complete(struct request *rq)
72{
73 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
74}
75
76static inline void blk_clear_rq_complete(struct request *rq)
77{
78 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
79}
86db1e29 80
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81/*
82 * Internal elevator interface
83 */
360f92c2 84#define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
158dbda0 85
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86void blk_insert_flush(struct request *rq);
87void blk_abort_flushes(struct request_queue *q);
dd831006 88
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89static inline struct request *__elv_next_request(struct request_queue *q)
90{
91 struct request *rq;
92
93 while (1) {
ae1b1539 94 if (!list_empty(&q->queue_head)) {
158dbda0 95 rq = list_entry_rq(q->queue_head.next);
ae1b1539 96 return rq;
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97 }
98
3ac0cc45 99 /*
100 * Flush request is running and flush request isn't queueable
101 * in the drive, we can hold the queue till flush request is
102 * finished. Even we don't do this, driver can't dispatch next
103 * requests and will requeue them. And this can improve
104 * throughput too. For example, we have request flush1, write1,
105 * flush 2. flush1 is dispatched, then queue is hold, write1
106 * isn't inserted to queue. After flush1 is finished, flush2
107 * will be dispatched. Since disk cache is already clean,
108 * flush2 will be finished very soon, so looks like flush2 is
109 * folded to flush1.
110 * Since the queue is hold, a flag is set to indicate the queue
111 * should be restarted later. Please see flush_end_io() for
112 * details.
113 */
114 if (q->flush_pending_idx != q->flush_running_idx &&
115 !queue_flush_queueable(q)) {
116 q->flush_queue_delayed = 1;
117 return NULL;
118 }
556ee818 119 if (unlikely(blk_queue_bypass(q)) ||
22f746e2 120 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
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121 return NULL;
122 }
123}
124
125static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
126{
127 struct elevator_queue *e = q->elevator;
128
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129 if (e->type->ops.elevator_activate_req_fn)
130 e->type->ops.elevator_activate_req_fn(q, rq);
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131}
132
133static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
134{
135 struct elevator_queue *e = q->elevator;
136
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137 if (e->type->ops.elevator_deactivate_req_fn)
138 e->type->ops.elevator_deactivate_req_fn(q, rq);
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139}
140
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141#ifdef CONFIG_FAIL_IO_TIMEOUT
142int blk_should_fake_timeout(struct request_queue *);
143ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
144ssize_t part_timeout_store(struct device *, struct device_attribute *,
145 const char *, size_t);
146#else
147static inline int blk_should_fake_timeout(struct request_queue *q)
148{
149 return 0;
150}
151#endif
152
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153int ll_back_merge_fn(struct request_queue *q, struct request *req,
154 struct bio *bio);
155int ll_front_merge_fn(struct request_queue *q, struct request *req,
156 struct bio *bio);
157int attempt_back_merge(struct request_queue *q, struct request *rq);
158int attempt_front_merge(struct request_queue *q, struct request *rq);
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159int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
160 struct request *next);
d6d48196 161void blk_recalc_rq_segments(struct request *rq);
80a761fd 162void blk_rq_set_mixed_merge(struct request *rq);
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163bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
164int blk_try_merge(struct request *rq, struct bio *bio);
d6d48196 165
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166void blk_queue_congestion_threshold(struct request_queue *q);
167
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168void __blk_run_queue_uncond(struct request_queue *q);
169
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170int blk_dev_init(void);
171
f253b86b 172
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173/*
174 * Return the threshold (number of used requests) at which the queue is
175 * considered to be congested. It include a little hysteresis to keep the
176 * context switch rate down.
177 */
178static inline int queue_congestion_on_threshold(struct request_queue *q)
179{
180 return q->nr_congestion_on;
181}
182
183/*
184 * The threshold at which a queue is considered to be uncongested
185 */
186static inline int queue_congestion_off_threshold(struct request_queue *q)
187{
188 return q->nr_congestion_off;
189}
190
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191extern int blk_update_nr_requests(struct request_queue *, unsigned int);
192
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193/*
194 * Contribute to IO statistics IFF:
195 *
196 * a) it's attached to a gendisk, and
197 * b) the queue had IO stats enabled when this request was started, and
e2a60da7 198 * c) it's a file system request
c2553b58 199 */
26308eab 200static inline int blk_do_io_stat(struct request *rq)
fb8ec18c 201{
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202 return rq->rq_disk &&
203 (rq->cmd_flags & REQ_IO_STAT) &&
e2a60da7 204 (rq->cmd_type == REQ_TYPE_FS);
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205}
206
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207/*
208 * Internal io_context interface
209 */
210void get_io_context(struct io_context *ioc);
47fdd4ca 211struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
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212struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
213 gfp_t gfp_mask);
7e5a8794 214void ioc_clear_queue(struct request_queue *q);
f2dbd76a 215
24acfc34 216int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
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217
218/**
219 * create_io_context - try to create task->io_context
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220 * @gfp_mask: allocation mask
221 * @node: allocation node
222 *
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223 * If %current->io_context is %NULL, allocate a new io_context and install
224 * it. Returns the current %current->io_context which may be %NULL if
225 * allocation failed.
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226 *
227 * Note that this function can't be called with IRQ disabled because
24acfc34 228 * task_lock which protects %current->io_context is IRQ-unsafe.
f2dbd76a 229 */
24acfc34 230static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
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231{
232 WARN_ON_ONCE(irqs_disabled());
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233 if (unlikely(!current->io_context))
234 create_task_io_context(current, gfp_mask, node);
235 return current->io_context;
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236}
237
238/*
239 * Internal throttling interface
240 */
bc9fcbf9 241#ifdef CONFIG_BLK_DEV_THROTTLING
bc16a4f9 242extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
c9a929dd 243extern void blk_throtl_drain(struct request_queue *q);
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244extern int blk_throtl_init(struct request_queue *q);
245extern void blk_throtl_exit(struct request_queue *q);
246#else /* CONFIG_BLK_DEV_THROTTLING */
bc16a4f9 247static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
bc9fcbf9 248{
bc16a4f9 249 return false;
bc9fcbf9 250}
c9a929dd 251static inline void blk_throtl_drain(struct request_queue *q) { }
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252static inline int blk_throtl_init(struct request_queue *q) { return 0; }
253static inline void blk_throtl_exit(struct request_queue *q) { }
254#endif /* CONFIG_BLK_DEV_THROTTLING */
255
256#endif /* BLK_INTERNAL_H */