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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 Heoc9a929d2011-10-19 14:42:16 +020018void blk_drain_queue(struct request_queue *q, bool drain_all);
Tejun Heo9934c8c2009-05-08 11:54:16 +090019void blk_dequeue_request(struct request *rq);
Jens Axboe8324aa92008-01-29 14:51:59 +010020void __blk_queue_free_tags(struct request_queue *q);
Jeff Moyer4853aba2011-08-15 21:37:25 +020021bool __blk_end_bidi_request(struct request *rq, int error,
22 unsigned int nr_bytes, unsigned int bidi_bytes);
Jens Axboe8324aa92008-01-29 14:51:59 +010023
Jens Axboe242f9dc2008-09-14 05:55:09 -070024void blk_rq_timed_out_timer(unsigned long data);
25void blk_delete_timer(struct request *);
26void blk_add_timer(struct request *);
Jens Axboef73e2d12008-10-17 14:03:08 +020027void __generic_unplug_device(struct request_queue *);
Jens Axboe242f9dc2008-09-14 05:55:09 -070028
29/*
30 * Internal atomic flags for request handling
31 */
32enum rq_atomic_flags {
33 REQ_ATOM_COMPLETE = 0,
34};
35
36/*
37 * EH timer and IO completion will both attempt to 'grab' the request, make
Lucas De Marchi25985ed2011-03-30 22:57:33 -030038 * sure that only one of them succeeds
Jens Axboe242f9dc2008-09-14 05:55:09 -070039 */
40static inline int blk_mark_rq_complete(struct request *rq)
41{
42 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
43}
44
45static inline void blk_clear_rq_complete(struct request *rq)
46{
47 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
48}
Jens Axboe86db1e22008-01-29 14:53:40 +010049
Tejun Heo158dbda2009-04-23 11:05:18 +090050/*
51 * Internal elevator interface
52 */
53#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
54
Tejun Heoae1b1532011-01-25 12:43:54 +010055void blk_insert_flush(struct request *rq);
56void blk_abort_flushes(struct request_queue *q);
Tejun Heodd831002010-09-03 11:56:16 +020057
Tejun Heo158dbda2009-04-23 11:05:18 +090058static inline struct request *__elv_next_request(struct request_queue *q)
59{
60 struct request *rq;
61
62 while (1) {
Tejun Heoae1b1532011-01-25 12:43:54 +010063 if (!list_empty(&q->queue_head)) {
Tejun Heo158dbda2009-04-23 11:05:18 +090064 rq = list_entry_rq(q->queue_head.next);
Tejun Heoae1b1532011-01-25 12:43:54 +010065 return rq;
Tejun Heo158dbda2009-04-23 11:05:18 +090066 }
67
shaohua.li@intel.com3ac0cc42011-05-06 11:34:41 -060068 /*
69 * Flush request is running and flush request isn't queueable
70 * in the drive, we can hold the queue till flush request is
71 * finished. Even we don't do this, driver can't dispatch next
72 * requests and will requeue them. And this can improve
73 * throughput too. For example, we have request flush1, write1,
74 * flush 2. flush1 is dispatched, then queue is hold, write1
75 * isn't inserted to queue. After flush1 is finished, flush2
76 * will be dispatched. Since disk cache is already clean,
77 * flush2 will be finished very soon, so looks like flush2 is
78 * folded to flush1.
79 * Since the queue is hold, a flag is set to indicate the queue
80 * should be restarted later. Please see flush_end_io() for
81 * details.
82 */
83 if (q->flush_pending_idx != q->flush_running_idx &&
84 !queue_flush_queueable(q)) {
85 q->flush_queue_delayed = 1;
86 return NULL;
87 }
James Bottomley0a58e072011-05-18 16:20:10 +020088 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
89 !q->elevator->ops->elevator_dispatch_fn(q, 0))
Tejun Heo158dbda2009-04-23 11:05:18 +090090 return NULL;
91 }
92}
93
94static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
95{
96 struct elevator_queue *e = q->elevator;
97
98 if (e->ops->elevator_activate_req_fn)
99 e->ops->elevator_activate_req_fn(q, rq);
100}
101
102static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
103{
104 struct elevator_queue *e = q->elevator;
105
106 if (e->ops->elevator_deactivate_req_fn)
107 e->ops->elevator_deactivate_req_fn(q, rq);
108}
109
Jens Axboe581d4e22008-09-14 05:56:33 -0700110#ifdef CONFIG_FAIL_IO_TIMEOUT
111int blk_should_fake_timeout(struct request_queue *);
112ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
113ssize_t part_timeout_store(struct device *, struct device_attribute *,
114 const char *, size_t);
115#else
116static inline int blk_should_fake_timeout(struct request_queue *q)
117{
118 return 0;
119}
120#endif
121
Jens Axboe86db1e22008-01-29 14:53:40 +0100122struct io_context *current_io_context(gfp_t gfp_flags, int node);
123
Jens Axboed6d48192008-01-29 14:04:06 +0100124int ll_back_merge_fn(struct request_queue *q, struct request *req,
125 struct bio *bio);
126int ll_front_merge_fn(struct request_queue *q, struct request *req,
127 struct bio *bio);
128int attempt_back_merge(struct request_queue *q, struct request *rq);
129int attempt_front_merge(struct request_queue *q, struct request *rq);
Jens Axboe5e84ea32011-03-21 10:14:27 +0100130int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
131 struct request *next);
Jens Axboed6d48192008-01-29 14:04:06 +0100132void blk_recalc_rq_segments(struct request *rq);
Tejun Heo80a761f2009-07-03 17:48:17 +0900133void blk_rq_set_mixed_merge(struct request *rq);
Jens Axboed6d48192008-01-29 14:04:06 +0100134
Jens Axboe8324aa92008-01-29 14:51:59 +0100135void blk_queue_congestion_threshold(struct request_queue *q);
136
Adrian Bunkff889722008-03-04 11:23:45 +0100137int blk_dev_init(void);
138
Jens Axboef253b862010-10-24 22:06:02 +0200139void elv_quiesce_start(struct request_queue *q);
140void elv_quiesce_end(struct request_queue *q);
141
142
Jens Axboe8324aa92008-01-29 14:51:59 +0100143/*
144 * Return the threshold (number of used requests) at which the queue is
145 * considered to be congested. It include a little hysteresis to keep the
146 * context switch rate down.
147 */
148static inline int queue_congestion_on_threshold(struct request_queue *q)
149{
150 return q->nr_congestion_on;
151}
152
153/*
154 * The threshold at which a queue is considered to be uncongested
155 */
156static inline int queue_congestion_off_threshold(struct request_queue *q)
157{
158 return q->nr_congestion_off;
159}
160
Jens Axboec7c22e42008-09-13 20:26:01 +0200161static inline int blk_cpu_to_group(int cpu)
162{
Brian Kingbe14eb62010-09-10 09:03:21 +0200163 int group = NR_CPUS;
Jens Axboec7c22e42008-09-13 20:26:01 +0200164#ifdef CONFIG_SCHED_MC
Rusty Russellbe4d6382008-12-26 22:23:43 +1030165 const struct cpumask *mask = cpu_coregroup_mask(cpu);
Brian Kingbe14eb62010-09-10 09:03:21 +0200166 group = cpumask_first(mask);
Jens Axboec7c22e42008-09-13 20:26:01 +0200167#elif defined(CONFIG_SCHED_SMT)
Brian Kingbe14eb62010-09-10 09:03:21 +0200168 group = cpumask_first(topology_thread_cpumask(cpu));
Jens Axboec7c22e42008-09-13 20:26:01 +0200169#else
170 return cpu;
171#endif
Brian Kingbe14eb62010-09-10 09:03:21 +0200172 if (likely(group < NR_CPUS))
173 return group;
174 return cpu;
Jens Axboec7c22e42008-09-13 20:26:01 +0200175}
176
Jens Axboec2553b52009-04-24 08:10:11 +0200177/*
178 * Contribute to IO statistics IFF:
179 *
180 * a) it's attached to a gendisk, and
181 * b) the queue had IO stats enabled when this request was started, and
Kiyoshi Ueda3c4198e2009-05-27 14:50:02 +0200182 * c) it's a file system request or a discard request
Jens Axboec2553b52009-04-24 08:10:11 +0200183 */
Jerome Marchand26308ea2009-03-27 10:31:51 +0100184static inline int blk_do_io_stat(struct request *rq)
Jens Axboefb8ec182009-02-02 08:42:32 +0100185{
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200186 return rq->rq_disk &&
187 (rq->cmd_flags & REQ_IO_STAT) &&
188 (rq->cmd_type == REQ_TYPE_FS ||
189 (rq->cmd_flags & REQ_DISCARD));
Jens Axboefb8ec182009-02-02 08:42:32 +0100190}
191
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200192#ifdef CONFIG_BLK_DEV_THROTTLING
Tejun Heobc16a4f2011-10-19 14:33:01 +0200193extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
Tejun Heoc9a929d2011-10-19 14:42:16 +0200194extern void blk_throtl_drain(struct request_queue *q);
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200195extern int blk_throtl_init(struct request_queue *q);
196extern void blk_throtl_exit(struct request_queue *q);
Tejun Heoc9a929d2011-10-19 14:42:16 +0200197extern void blk_throtl_release(struct request_queue *q);
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200198#else /* CONFIG_BLK_DEV_THROTTLING */
Tejun Heobc16a4f2011-10-19 14:33:01 +0200199static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200200{
Tejun Heobc16a4f2011-10-19 14:33:01 +0200201 return false;
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200202}
Tejun Heoc9a929d2011-10-19 14:42:16 +0200203static inline void blk_throtl_drain(struct request_queue *q) { }
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200204static inline int blk_throtl_init(struct request_queue *q) { return 0; }
205static inline void blk_throtl_exit(struct request_queue *q) { }
Tejun Heoc9a929d2011-10-19 14:42:16 +0200206static inline void blk_throtl_release(struct request_queue *q) { }
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200207#endif /* CONFIG_BLK_DEV_THROTTLING */
208
209#endif /* BLK_INTERNAL_H */