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
10 extern struct kmem_cache *blk_requestq_cachep;
11 extern struct kobj_type blk_queue_ktype;
12
13 void init_request_from_bio(struct request *req, struct bio *bio);
14 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
15 struct bio *bio);
16 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
17 struct bio *bio);
18 void blk_dequeue_request(struct request *rq);
19 void __blk_queue_free_tags(struct request_queue *q);
20
21 void blk_unplug_work(struct work_struct *work);
22 void blk_unplug_timeout(unsigned long data);
23 void blk_rq_timed_out_timer(unsigned long data);
24 void blk_delete_timer(struct request *);
25 void blk_add_timer(struct request *);
26 void __generic_unplug_device(struct request_queue *);
27
28 /*
29 * Internal atomic flags for request handling
30 */
31 enum 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 */
39 static inline int blk_mark_rq_complete(struct request *rq)
40 {
41 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
42 }
43
44 static 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
54 static 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
70 static 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
78 static 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
87 int blk_should_fake_timeout(struct request_queue *);
88 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
89 ssize_t part_timeout_store(struct device *, struct device_attribute *,
90 const char *, size_t);
91 #else
92 static inline int blk_should_fake_timeout(struct request_queue *q)
93 {
94 return 0;
95 }
96 #endif
97
98 struct io_context *current_io_context(gfp_t gfp_flags, int node);
99
100 int ll_back_merge_fn(struct request_queue *q, struct request *req,
101 struct bio *bio);
102 int ll_front_merge_fn(struct request_queue *q, struct request *req,
103 struct bio *bio);
104 int attempt_back_merge(struct request_queue *q, struct request *rq);
105 int attempt_front_merge(struct request_queue *q, struct request *rq);
106 void blk_recalc_rq_segments(struct request *rq);
107
108 void blk_queue_congestion_threshold(struct request_queue *q);
109
110 int blk_dev_init(void);
111
112 void elv_quiesce_start(struct request_queue *q);
113 void elv_quiesce_end(struct request_queue *q);
114
115
116 /*
117 * Return the threshold (number of used requests) at which the queue is
118 * considered to be congested. It include a little hysteresis to keep the
119 * context switch rate down.
120 */
121 static inline int queue_congestion_on_threshold(struct request_queue *q)
122 {
123 return q->nr_congestion_on;
124 }
125
126 /*
127 * The threshold at which a queue is considered to be uncongested
128 */
129 static inline int queue_congestion_off_threshold(struct request_queue *q)
130 {
131 return q->nr_congestion_off;
132 }
133
134 #if defined(CONFIG_BLK_DEV_INTEGRITY)
135
136 #define rq_for_each_integrity_segment(bvl, _rq, _iter) \
137 __rq_for_each_bio(_iter.bio, _rq) \
138 bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
139
140 #endif /* BLK_DEV_INTEGRITY */
141
142 static inline int blk_cpu_to_group(int cpu)
143 {
144 #ifdef CONFIG_SCHED_MC
145 const struct cpumask *mask = cpu_coregroup_mask(cpu);
146 return cpumask_first(mask);
147 #elif defined(CONFIG_SCHED_SMT)
148 return cpumask_first(topology_thread_cpumask(cpu));
149 #else
150 return cpu;
151 #endif
152 }
153
154 /*
155 * Contribute to IO statistics IFF:
156 *
157 * a) it's attached to a gendisk, and
158 * b) the queue had IO stats enabled when this request was started, and
159 * c) it's a file system request or a discard request
160 */
161 static inline int blk_do_io_stat(struct request *rq)
162 {
163 return rq->rq_disk && blk_rq_io_stat(rq) &&
164 (blk_fs_request(rq) || blk_discard_rq(rq));
165 }
166
167 #endif
168
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