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1#ifndef BLK_INTERNAL_H
2#define BLK_INTERNAL_H
3
4/* Amount of time in which a process may batch requests */
5#define BLK_BATCH_TIME (HZ/50UL)
6
7/* Number of requests a "batching" process may submit */
8#define BLK_BATCH_REQ 32
9
10extern struct kmem_cache *blk_requestq_cachep;
11extern struct kobj_type blk_queue_ktype;
12
13void init_request_from_bio(struct request *req, struct bio *bio);
14void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
15 struct bio *bio);
16int blk_rq_append_bio(struct request_queue *q, struct request *rq,
17 struct bio *bio);
18void blk_dequeue_request(struct request *rq);
19void __blk_queue_free_tags(struct request_queue *q);
20
21void blk_rq_timed_out_timer(unsigned long data);
22void blk_delete_timer(struct request *);
23void blk_add_timer(struct request *);
24void __generic_unplug_device(struct request_queue *);
25
26/*
27 * Internal atomic flags for request handling
28 */
29enum rq_atomic_flags {
30 REQ_ATOM_COMPLETE = 0,
31};
32
33/*
34 * EH timer and IO completion will both attempt to 'grab' the request, make
35 * sure that only one of them succeeds
36 */
37static inline int blk_mark_rq_complete(struct request *rq)
38{
39 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
40}
41
42static inline void blk_clear_rq_complete(struct request *rq)
43{
44 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
45}
46
47/*
48 * Internal elevator interface
49 */
50#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
51
52void blk_insert_flush(struct request *rq);
53void blk_abort_flushes(struct request_queue *q);
54
55static inline struct request *__elv_next_request(struct request_queue *q)
56{
57 struct request *rq;
58
59 while (1) {
60 if (!list_empty(&q->queue_head)) {
61 rq = list_entry_rq(q->queue_head.next);
62 return rq;
63 }
64
65 if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
66 return NULL;
67 }
68}
69
70static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
71{
72 struct elevator_queue *e = q->elevator;
73
74 if (e->ops->elevator_activate_req_fn)
75 e->ops->elevator_activate_req_fn(q, rq);
76}
77
78static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
79{
80 struct elevator_queue *e = q->elevator;
81
82 if (e->ops->elevator_deactivate_req_fn)
83 e->ops->elevator_deactivate_req_fn(q, rq);
84}
85
86#ifdef CONFIG_FAIL_IO_TIMEOUT
87int blk_should_fake_timeout(struct request_queue *);
88ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
89ssize_t part_timeout_store(struct device *, struct device_attribute *,
90 const char *, size_t);
91#else
92static inline int blk_should_fake_timeout(struct request_queue *q)
93{
94 return 0;
95}
96#endif
97
98struct io_context *current_io_context(gfp_t gfp_flags, int node);
99
100int ll_back_merge_fn(struct request_queue *q, struct request *req,
101 struct bio *bio);
102int ll_front_merge_fn(struct request_queue *q, struct request *req,
103 struct bio *bio);
104int attempt_back_merge(struct request_queue *q, struct request *rq);
105int attempt_front_merge(struct request_queue *q, struct request *rq);
106int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
107 struct request *next);
108void blk_recalc_rq_segments(struct request *rq);
109void blk_rq_set_mixed_merge(struct request *rq);
110
111void blk_queue_congestion_threshold(struct request_queue *q);
112
113int blk_dev_init(void);
114
115void elv_quiesce_start(struct request_queue *q);
116void elv_quiesce_end(struct request_queue *q);
117
118
119/*
120 * Return the threshold (number of used requests) at which the queue is
121 * considered to be congested. It include a little hysteresis to keep the
122 * context switch rate down.
123 */
124static inline int queue_congestion_on_threshold(struct request_queue *q)
125{
126 return q->nr_congestion_on;
127}
128
129/*
130 * The threshold at which a queue is considered to be uncongested
131 */
132static inline int queue_congestion_off_threshold(struct request_queue *q)
133{
134 return q->nr_congestion_off;
135}
136
137static inline int blk_cpu_to_group(int cpu)
138{
139 int group = NR_CPUS;
140#ifdef CONFIG_SCHED_MC
141 const struct cpumask *mask = cpu_coregroup_mask(cpu);
142 group = cpumask_first(mask);
143#elif defined(CONFIG_SCHED_SMT)
144 group = cpumask_first(topology_thread_cpumask(cpu));
145#else
146 return cpu;
147#endif
148 if (likely(group < NR_CPUS))
149 return group;
150 return cpu;
151}
152
153/*
154 * Contribute to IO statistics IFF:
155 *
156 * a) it's attached to a gendisk, and
157 * b) the queue had IO stats enabled when this request was started, and
158 * c) it's a file system request or a discard request
159 */
160static inline int blk_do_io_stat(struct request *rq)
161{
162 return rq->rq_disk &&
163 (rq->cmd_flags & REQ_IO_STAT) &&
164 (rq->cmd_type == REQ_TYPE_FS ||
165 (rq->cmd_flags & REQ_DISCARD));
166}
167
168#endif