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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);
Jeff Moyer4853aba2011-08-15 21:37:25 +020020bool __blk_end_bidi_request(struct request *rq, int error,
21 unsigned int nr_bytes, unsigned int bidi_bytes);
Jens Axboe8324aa92008-01-29 14:51:59 +010022
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
Lucas De Marchi25985ed2011-03-30 22:57:33 -030037 * sure that only one of them succeeds
Jens Axboe242f9dc2008-09-14 05:55:09 -070038 */
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
Tejun Heoae1b1532011-01-25 12:43:54 +010054void blk_insert_flush(struct request *rq);
55void blk_abort_flushes(struct request_queue *q);
Tejun Heodd831002010-09-03 11:56:16 +020056
Tejun Heo158dbda2009-04-23 11:05:18 +090057static inline struct request *__elv_next_request(struct request_queue *q)
58{
59 struct request *rq;
60
61 while (1) {
Tejun Heoae1b1532011-01-25 12:43:54 +010062 if (!list_empty(&q->queue_head)) {
Tejun Heo158dbda2009-04-23 11:05:18 +090063 rq = list_entry_rq(q->queue_head.next);
Tejun Heoae1b1532011-01-25 12:43:54 +010064 return rq;
Tejun Heo158dbda2009-04-23 11:05:18 +090065 }
66
shaohua.li@intel.com3ac0cc42011-05-06 11:34:41 -060067 /*
68 * Flush request is running and flush request isn't queueable
69 * in the drive, we can hold the queue till flush request is
70 * finished. Even we don't do this, driver can't dispatch next
71 * requests and will requeue them. And this can improve
72 * throughput too. For example, we have request flush1, write1,
73 * flush 2. flush1 is dispatched, then queue is hold, write1
74 * isn't inserted to queue. After flush1 is finished, flush2
75 * will be dispatched. Since disk cache is already clean,
76 * flush2 will be finished very soon, so looks like flush2 is
77 * folded to flush1.
78 * Since the queue is hold, a flag is set to indicate the queue
79 * should be restarted later. Please see flush_end_io() for
80 * details.
81 */
82 if (q->flush_pending_idx != q->flush_running_idx &&
83 !queue_flush_queueable(q)) {
84 q->flush_queue_delayed = 1;
85 return NULL;
86 }
James Bottomley0a58e072011-05-18 16:20:10 +020087 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
88 !q->elevator->ops->elevator_dispatch_fn(q, 0))
Tejun Heo158dbda2009-04-23 11:05:18 +090089 return NULL;
90 }
91}
92
93static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
94{
95 struct elevator_queue *e = q->elevator;
96
97 if (e->ops->elevator_activate_req_fn)
98 e->ops->elevator_activate_req_fn(q, rq);
99}
100
101static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
102{
103 struct elevator_queue *e = q->elevator;
104
105 if (e->ops->elevator_deactivate_req_fn)
106 e->ops->elevator_deactivate_req_fn(q, rq);
107}
108
Jens Axboe581d4e22008-09-14 05:56:33 -0700109#ifdef CONFIG_FAIL_IO_TIMEOUT
110int blk_should_fake_timeout(struct request_queue *);
111ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
112ssize_t part_timeout_store(struct device *, struct device_attribute *,
113 const char *, size_t);
114#else
115static inline int blk_should_fake_timeout(struct request_queue *q)
116{
117 return 0;
118}
119#endif
120
Jens Axboe86db1e22008-01-29 14:53:40 +0100121struct io_context *current_io_context(gfp_t gfp_flags, int node);
122
Jens Axboed6d48192008-01-29 14:04:06 +0100123int ll_back_merge_fn(struct request_queue *q, struct request *req,
124 struct bio *bio);
125int ll_front_merge_fn(struct request_queue *q, struct request *req,
126 struct bio *bio);
127int attempt_back_merge(struct request_queue *q, struct request *rq);
128int attempt_front_merge(struct request_queue *q, struct request *rq);
Jens Axboe5e84ea32011-03-21 10:14:27 +0100129int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
130 struct request *next);
Jens Axboed6d48192008-01-29 14:04:06 +0100131void blk_recalc_rq_segments(struct request *rq);
Tejun Heo80a761f2009-07-03 17:48:17 +0900132void blk_rq_set_mixed_merge(struct request *rq);
Jens Axboed6d48192008-01-29 14:04:06 +0100133
Jens Axboe8324aa92008-01-29 14:51:59 +0100134void blk_queue_congestion_threshold(struct request_queue *q);
135
Adrian Bunkff889722008-03-04 11:23:45 +0100136int blk_dev_init(void);
137
Jens Axboef253b862010-10-24 22:06:02 +0200138void elv_quiesce_start(struct request_queue *q);
139void elv_quiesce_end(struct request_queue *q);
140
141
Jens Axboe8324aa92008-01-29 14:51:59 +0100142/*
143 * Return the threshold (number of used requests) at which the queue is
144 * considered to be congested. It include a little hysteresis to keep the
145 * context switch rate down.
146 */
147static inline int queue_congestion_on_threshold(struct request_queue *q)
148{
149 return q->nr_congestion_on;
150}
151
152/*
153 * The threshold at which a queue is considered to be uncongested
154 */
155static inline int queue_congestion_off_threshold(struct request_queue *q)
156{
157 return q->nr_congestion_off;
158}
159
Jens Axboec7c22e42008-09-13 20:26:01 +0200160static inline int blk_cpu_to_group(int cpu)
161{
Brian Kingbe14eb62010-09-10 09:03:21 +0200162 int group = NR_CPUS;
Jens Axboec7c22e42008-09-13 20:26:01 +0200163#ifdef CONFIG_SCHED_MC
Rusty Russellbe4d6382008-12-26 22:23:43 +1030164 const struct cpumask *mask = cpu_coregroup_mask(cpu);
Brian Kingbe14eb62010-09-10 09:03:21 +0200165 group = cpumask_first(mask);
Jens Axboec7c22e42008-09-13 20:26:01 +0200166#elif defined(CONFIG_SCHED_SMT)
Brian Kingbe14eb62010-09-10 09:03:21 +0200167 group = cpumask_first(topology_thread_cpumask(cpu));
Jens Axboec7c22e42008-09-13 20:26:01 +0200168#else
169 return cpu;
170#endif
Brian Kingbe14eb62010-09-10 09:03:21 +0200171 if (likely(group < NR_CPUS))
172 return group;
173 return cpu;
Jens Axboec7c22e42008-09-13 20:26:01 +0200174}
175
Jens Axboec2553b52009-04-24 08:10:11 +0200176/*
177 * Contribute to IO statistics IFF:
178 *
179 * a) it's attached to a gendisk, and
180 * b) the queue had IO stats enabled when this request was started, and
Kiyoshi Ueda3c4198e2009-05-27 14:50:02 +0200181 * c) it's a file system request or a discard request
Jens Axboec2553b52009-04-24 08:10:11 +0200182 */
Jerome Marchand26308ea2009-03-27 10:31:51 +0100183static inline int blk_do_io_stat(struct request *rq)
Jens Axboefb8ec182009-02-02 08:42:32 +0100184{
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200185 return rq->rq_disk &&
186 (rq->cmd_flags & REQ_IO_STAT) &&
187 (rq->cmd_type == REQ_TYPE_FS ||
188 (rq->cmd_flags & REQ_DISCARD));
Jens Axboefb8ec182009-02-02 08:42:32 +0100189}
190
Jens Axboe8324aa92008-01-29 14:51:59 +0100191#endif