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_unplug_work(struct work_struct *work);
22void blk_unplug_timeout(unsigned long data);
23void blk_rq_timed_out_timer(unsigned long data);
24void blk_delete_timer(struct request *);
25void blk_add_timer(struct request *);
26void __generic_unplug_device(struct request_queue *);
27
28/*
29 * Internal atomic flags for request handling
30 */
31enum rq_atomic_flags {
32	REQ_ATOM_COMPLETE = 0,
33};
34
35/*
36 * EH timer and IO completion will both attempt to 'grab' the request, make
37 * sure that only one of them suceeds
38 */
39static inline int blk_mark_rq_complete(struct request *rq)
40{
41	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
42}
43
44static inline void blk_clear_rq_complete(struct request *rq)
45{
46	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
47}
48
49/*
50 * Internal elevator interface
51 */
52#define ELV_ON_HASH(rq)		(!hlist_unhashed(&(rq)->hash))
53
54static inline struct request *__elv_next_request(struct request_queue *q)
55{
56	struct request *rq;
57
58	while (1) {
59		while (!list_empty(&q->queue_head)) {
60			rq = list_entry_rq(q->queue_head.next);
61			if (blk_do_ordered(q, &rq))
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);
106void blk_recalc_rq_segments(struct request *rq);
107void blk_rq_set_mixed_merge(struct request *rq);
108
109void blk_queue_congestion_threshold(struct request_queue *q);
110
111int blk_dev_init(void);
112
113void elv_quiesce_start(struct request_queue *q);
114void elv_quiesce_end(struct request_queue *q);
115
116
117/*
118 * Return the threshold (number of used requests) at which the queue is
119 * considered to be congested.  It include a little hysteresis to keep the
120 * context switch rate down.
121 */
122static inline int queue_congestion_on_threshold(struct request_queue *q)
123{
124	return q->nr_congestion_on;
125}
126
127/*
128 * The threshold at which a queue is considered to be uncongested
129 */
130static inline int queue_congestion_off_threshold(struct request_queue *q)
131{
132	return q->nr_congestion_off;
133}
134
135#if defined(CONFIG_BLK_DEV_INTEGRITY)
136
137#define rq_for_each_integrity_segment(bvl, _rq, _iter)		\
138	__rq_for_each_bio(_iter.bio, _rq)			\
139		bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
140
141#endif /* BLK_DEV_INTEGRITY */
142
143static inline int blk_cpu_to_group(int cpu)
144{
145	int group = NR_CPUS;
146#ifdef CONFIG_SCHED_MC
147	const struct cpumask *mask = cpu_coregroup_mask(cpu);
148	group = cpumask_first(mask);
149#elif defined(CONFIG_SCHED_SMT)
150	group = cpumask_first(topology_thread_cpumask(cpu));
151#else
152	return cpu;
153#endif
154	if (likely(group < NR_CPUS))
155		return group;
156	return cpu;
157}
158
159/*
160 * Contribute to IO statistics IFF:
161 *
162 *	a) it's attached to a gendisk, and
163 *	b) the queue had IO stats enabled when this request was started, and
164 *	c) it's a file system request or a discard request
165 */
166static inline int blk_do_io_stat(struct request *rq)
167{
168	return rq->rq_disk &&
169	       (rq->cmd_flags & REQ_IO_STAT) &&
170	       (rq->cmd_type == REQ_TYPE_FS ||
171	        (rq->cmd_flags & REQ_DISCARD));
172}
173
174#endif
175