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Jens Axboe8324aa92008-01-29 14:51:59 +01001#ifndef BLK_INTERNAL_H
2#define BLK_INTERNAL_H
3
Jens Axboe86db1e22008-01-29 14:53:40 +01004/* 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
Jens Axboe8324aa92008-01-29 14:51:59 +010010extern struct kmem_cache *blk_requestq_cachep;
11extern struct kobj_type blk_queue_ktype;
12
Jens Axboe86db1e22008-01-29 14:53:40 +010013void 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);
Boaz Harrosha411f4b2009-05-17 19:00:01 +030016int blk_rq_append_bio(struct request_queue *q, struct request *rq,
17 struct bio *bio);
Tejun Heo9934c8c2009-05-08 11:54:16 +090018void blk_dequeue_request(struct request *rq);
Jens Axboe8324aa92008-01-29 14:51:59 +010019void __blk_queue_free_tags(struct request_queue *q);
20
Jens Axboe86db1e22008-01-29 14:53:40 +010021void blk_unplug_work(struct work_struct *work);
22void blk_unplug_timeout(unsigned long data);
Jens Axboe242f9dc2008-09-14 05:55:09 -070023void blk_rq_timed_out_timer(unsigned long data);
24void blk_delete_timer(struct request *);
25void blk_add_timer(struct request *);
Jens Axboef73e2d12008-10-17 14:03:08 +020026void __generic_unplug_device(struct request_queue *);
Jens Axboe242f9dc2008-09-14 05:55:09 -070027
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}
Jens Axboe86db1e22008-01-29 14:53:40 +010048
Tejun Heo158dbda2009-04-23 11:05:18 +090049/*
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
Jens Axboe581d4e22008-09-14 05:56:33 -070086#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
Jens Axboe86db1e22008-01-29 14:53:40 +010098struct io_context *current_io_context(gfp_t gfp_flags, int node);
99
Jens Axboed6d48192008-01-29 14:04:06 +0100100int 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);
Tejun Heo80a761f2009-07-03 17:48:17 +0900107void blk_rq_set_mixed_merge(struct request *rq);
Jens Axboed6d48192008-01-29 14:04:06 +0100108
Jens Axboe8324aa92008-01-29 14:51:59 +0100109void blk_queue_congestion_threshold(struct request_queue *q);
110
Adrian Bunkff889722008-03-04 11:23:45 +0100111int blk_dev_init(void);
112
Jens Axboef600abe2009-04-08 14:22:01 +0200113void elv_quiesce_start(struct request_queue *q);
114void elv_quiesce_end(struct request_queue *q);
Jens Axboe6c7e8ce2009-03-27 10:30:47 +0100115
116
Jens Axboe8324aa92008-01-29 14:51:59 +0100117/*
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
Jens Axboec7c22e42008-09-13 20:26:01 +0200135static inline int blk_cpu_to_group(int cpu)
136{
137#ifdef CONFIG_SCHED_MC
Rusty Russellbe4d6382008-12-26 22:23:43 +1030138 const struct cpumask *mask = cpu_coregroup_mask(cpu);
139 return cpumask_first(mask);
Jens Axboec7c22e42008-09-13 20:26:01 +0200140#elif defined(CONFIG_SCHED_SMT)
Rusty Russellc69fc562009-03-13 14:49:46 +1030141 return cpumask_first(topology_thread_cpumask(cpu));
Jens Axboec7c22e42008-09-13 20:26:01 +0200142#else
143 return cpu;
144#endif
145}
146
Jens Axboec2553b52009-04-24 08:10:11 +0200147/*
148 * Contribute to IO statistics IFF:
149 *
150 * a) it's attached to a gendisk, and
151 * b) the queue had IO stats enabled when this request was started, and
Kiyoshi Ueda3c4198e2009-05-27 14:50:02 +0200152 * c) it's a file system request or a discard request
Jens Axboec2553b52009-04-24 08:10:11 +0200153 */
Jerome Marchand26308ea2009-03-27 10:31:51 +0100154static inline int blk_do_io_stat(struct request *rq)
Jens Axboefb8ec182009-02-02 08:42:32 +0100155{
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200156 return rq->rq_disk &&
157 (rq->cmd_flags & REQ_IO_STAT) &&
158 (rq->cmd_type == REQ_TYPE_FS ||
159 (rq->cmd_flags & REQ_DISCARD));
Jens Axboefb8ec182009-02-02 08:42:32 +0100160}
161
Jens Axboe8324aa92008-01-29 14:51:59 +0100162#endif