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Jens Axboe8324aa92008-01-29 14:51:59 +01001#ifndef BLK_INTERNAL_H
2#define BLK_INTERNAL_H
3
Tejun Heoa73f7302011-12-14 00:33:37 +01004#include <linux/idr.h>
5
Jens Axboe86db1e22008-01-29 14:53:40 +01006/* Amount of time in which a process may batch requests */
7#define BLK_BATCH_TIME (HZ/50UL)
8
9/* Number of requests a "batching" process may submit */
10#define BLK_BATCH_REQ 32
11
Jens Axboe8324aa92008-01-29 14:51:59 +010012extern struct kmem_cache *blk_requestq_cachep;
13extern struct kobj_type blk_queue_ktype;
Tejun Heoa73f7302011-12-14 00:33:37 +010014extern struct ida blk_queue_ida;
Jens Axboe8324aa92008-01-29 14:51:59 +010015
Tejun Heo09ac46c2011-12-14 00:33:38 +010016static inline void __blk_get_queue(struct request_queue *q)
17{
18 kobject_get(&q->kobj);
19}
20
Jens Axboe86db1e22008-01-29 14:53:40 +010021void init_request_from_bio(struct request *req, struct bio *bio);
22void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
23 struct bio *bio);
Boaz Harrosha411f4b2009-05-17 19:00:01 +030024int blk_rq_append_bio(struct request_queue *q, struct request *rq,
25 struct bio *bio);
Tejun Heoc9a929d2011-10-19 14:42:16 +020026void blk_drain_queue(struct request_queue *q, bool drain_all);
Tejun Heo9934c8c2009-05-08 11:54:16 +090027void blk_dequeue_request(struct request *rq);
Jens Axboe8324aa92008-01-29 14:51:59 +010028void __blk_queue_free_tags(struct request_queue *q);
Jeff Moyer4853aba2011-08-15 21:37:25 +020029bool __blk_end_bidi_request(struct request *rq, int error,
30 unsigned int nr_bytes, unsigned int bidi_bytes);
Jens Axboe8324aa92008-01-29 14:51:59 +010031
Jens Axboe242f9dc2008-09-14 05:55:09 -070032void blk_rq_timed_out_timer(unsigned long data);
33void blk_delete_timer(struct request *);
34void blk_add_timer(struct request *);
Jens Axboef73e2d12008-10-17 14:03:08 +020035void __generic_unplug_device(struct request_queue *);
Jens Axboe242f9dc2008-09-14 05:55:09 -070036
37/*
38 * Internal atomic flags for request handling
39 */
40enum rq_atomic_flags {
41 REQ_ATOM_COMPLETE = 0,
42};
43
44/*
45 * EH timer and IO completion will both attempt to 'grab' the request, make
Lucas De Marchi25985ed2011-03-30 22:57:33 -030046 * sure that only one of them succeeds
Jens Axboe242f9dc2008-09-14 05:55:09 -070047 */
48static inline int blk_mark_rq_complete(struct request *rq)
49{
50 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
51}
52
53static inline void blk_clear_rq_complete(struct request *rq)
54{
55 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
56}
Jens Axboe86db1e22008-01-29 14:53:40 +010057
Tejun Heo158dbda2009-04-23 11:05:18 +090058/*
59 * Internal elevator interface
60 */
61#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
62
Tejun Heoae1b1532011-01-25 12:43:54 +010063void blk_insert_flush(struct request *rq);
64void blk_abort_flushes(struct request_queue *q);
Tejun Heodd831002010-09-03 11:56:16 +020065
Tejun Heo158dbda2009-04-23 11:05:18 +090066static inline struct request *__elv_next_request(struct request_queue *q)
67{
68 struct request *rq;
69
70 while (1) {
Tejun Heoae1b1532011-01-25 12:43:54 +010071 if (!list_empty(&q->queue_head)) {
Tejun Heo158dbda2009-04-23 11:05:18 +090072 rq = list_entry_rq(q->queue_head.next);
Tejun Heoae1b1532011-01-25 12:43:54 +010073 return rq;
Tejun Heo158dbda2009-04-23 11:05:18 +090074 }
75
shaohua.li@intel.com3ac0cc42011-05-06 11:34:41 -060076 /*
77 * Flush request is running and flush request isn't queueable
78 * in the drive, we can hold the queue till flush request is
79 * finished. Even we don't do this, driver can't dispatch next
80 * requests and will requeue them. And this can improve
81 * throughput too. For example, we have request flush1, write1,
82 * flush 2. flush1 is dispatched, then queue is hold, write1
83 * isn't inserted to queue. After flush1 is finished, flush2
84 * will be dispatched. Since disk cache is already clean,
85 * flush2 will be finished very soon, so looks like flush2 is
86 * folded to flush1.
87 * Since the queue is hold, a flag is set to indicate the queue
88 * should be restarted later. Please see flush_end_io() for
89 * details.
90 */
91 if (q->flush_pending_idx != q->flush_running_idx &&
92 !queue_flush_queueable(q)) {
93 q->flush_queue_delayed = 1;
94 return NULL;
95 }
Tejun Heo34f60552011-12-14 00:33:37 +010096 if (unlikely(blk_queue_dead(q)) ||
Tejun Heo22f746e2011-12-14 00:33:41 +010097 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
Tejun Heo158dbda2009-04-23 11:05:18 +090098 return NULL;
99 }
100}
101
102static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
103{
104 struct elevator_queue *e = q->elevator;
105
Tejun Heo22f746e2011-12-14 00:33:41 +0100106 if (e->type->ops.elevator_activate_req_fn)
107 e->type->ops.elevator_activate_req_fn(q, rq);
Tejun Heo158dbda2009-04-23 11:05:18 +0900108}
109
110static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
111{
112 struct elevator_queue *e = q->elevator;
113
Tejun Heo22f746e2011-12-14 00:33:41 +0100114 if (e->type->ops.elevator_deactivate_req_fn)
115 e->type->ops.elevator_deactivate_req_fn(q, rq);
Tejun Heo158dbda2009-04-23 11:05:18 +0900116}
117
Jens Axboe581d4e22008-09-14 05:56:33 -0700118#ifdef CONFIG_FAIL_IO_TIMEOUT
119int blk_should_fake_timeout(struct request_queue *);
120ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
121ssize_t part_timeout_store(struct device *, struct device_attribute *,
122 const char *, size_t);
123#else
124static inline int blk_should_fake_timeout(struct request_queue *q)
125{
126 return 0;
127}
128#endif
129
Jens Axboed6d48192008-01-29 14:04:06 +0100130int ll_back_merge_fn(struct request_queue *q, struct request *req,
131 struct bio *bio);
132int ll_front_merge_fn(struct request_queue *q, struct request *req,
133 struct bio *bio);
134int attempt_back_merge(struct request_queue *q, struct request *rq);
135int attempt_front_merge(struct request_queue *q, struct request *rq);
Jens Axboe5e84ea32011-03-21 10:14:27 +0100136int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
137 struct request *next);
Jens Axboed6d48192008-01-29 14:04:06 +0100138void blk_recalc_rq_segments(struct request *rq);
Tejun Heo80a761f2009-07-03 17:48:17 +0900139void blk_rq_set_mixed_merge(struct request *rq);
Jens Axboed6d48192008-01-29 14:04:06 +0100140
Jens Axboe8324aa92008-01-29 14:51:59 +0100141void blk_queue_congestion_threshold(struct request_queue *q);
142
Adrian Bunkff889722008-03-04 11:23:45 +0100143int blk_dev_init(void);
144
Jens Axboef253b862010-10-24 22:06:02 +0200145void elv_quiesce_start(struct request_queue *q);
146void elv_quiesce_end(struct request_queue *q);
147
148
Jens Axboe8324aa92008-01-29 14:51:59 +0100149/*
150 * Return the threshold (number of used requests) at which the queue is
151 * considered to be congested. It include a little hysteresis to keep the
152 * context switch rate down.
153 */
154static inline int queue_congestion_on_threshold(struct request_queue *q)
155{
156 return q->nr_congestion_on;
157}
158
159/*
160 * The threshold at which a queue is considered to be uncongested
161 */
162static inline int queue_congestion_off_threshold(struct request_queue *q)
163{
164 return q->nr_congestion_off;
165}
166
Jens Axboec7c22e42008-09-13 20:26:01 +0200167static inline int blk_cpu_to_group(int cpu)
168{
Brian Kingbe14eb62010-09-10 09:03:21 +0200169 int group = NR_CPUS;
Jens Axboec7c22e42008-09-13 20:26:01 +0200170#ifdef CONFIG_SCHED_MC
Rusty Russellbe4d6382008-12-26 22:23:43 +1030171 const struct cpumask *mask = cpu_coregroup_mask(cpu);
Brian Kingbe14eb62010-09-10 09:03:21 +0200172 group = cpumask_first(mask);
Jens Axboec7c22e42008-09-13 20:26:01 +0200173#elif defined(CONFIG_SCHED_SMT)
Brian Kingbe14eb62010-09-10 09:03:21 +0200174 group = cpumask_first(topology_thread_cpumask(cpu));
Jens Axboec7c22e42008-09-13 20:26:01 +0200175#else
176 return cpu;
177#endif
Brian Kingbe14eb62010-09-10 09:03:21 +0200178 if (likely(group < NR_CPUS))
179 return group;
180 return cpu;
Jens Axboec7c22e42008-09-13 20:26:01 +0200181}
182
Jens Axboec2553b52009-04-24 08:10:11 +0200183/*
184 * Contribute to IO statistics IFF:
185 *
186 * a) it's attached to a gendisk, and
187 * b) the queue had IO stats enabled when this request was started, and
Kiyoshi Ueda3c4198e2009-05-27 14:50:02 +0200188 * c) it's a file system request or a discard request
Jens Axboec2553b52009-04-24 08:10:11 +0200189 */
Jerome Marchand26308ea2009-03-27 10:31:51 +0100190static inline int blk_do_io_stat(struct request *rq)
Jens Axboefb8ec182009-02-02 08:42:32 +0100191{
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200192 return rq->rq_disk &&
193 (rq->cmd_flags & REQ_IO_STAT) &&
194 (rq->cmd_type == REQ_TYPE_FS ||
195 (rq->cmd_flags & REQ_DISCARD));
Jens Axboefb8ec182009-02-02 08:42:32 +0100196}
197
Tejun Heof2dbd762011-12-14 00:33:40 +0100198/*
199 * Internal io_context interface
200 */
201void get_io_context(struct io_context *ioc);
202
203void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_mask,
204 int node);
205
206/**
207 * create_io_context - try to create task->io_context
208 * @task: target task
209 * @gfp_mask: allocation mask
210 * @node: allocation node
211 *
212 * If @task->io_context is %NULL, allocate a new io_context and install it.
213 * Returns the current @task->io_context which may be %NULL if allocation
214 * failed.
215 *
216 * Note that this function can't be called with IRQ disabled because
217 * task_lock which protects @task->io_context is IRQ-unsafe.
218 */
219static inline struct io_context *create_io_context(struct task_struct *task,
220 gfp_t gfp_mask, int node)
221{
222 WARN_ON_ONCE(irqs_disabled());
223 if (unlikely(!task->io_context))
224 create_io_context_slowpath(task, gfp_mask, node);
225 return task->io_context;
226}
227
228/*
229 * Internal throttling interface
230 */
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200231#ifdef CONFIG_BLK_DEV_THROTTLING
Tejun Heobc16a4f2011-10-19 14:33:01 +0200232extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
Tejun Heoc9a929d2011-10-19 14:42:16 +0200233extern void blk_throtl_drain(struct request_queue *q);
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200234extern int blk_throtl_init(struct request_queue *q);
235extern void blk_throtl_exit(struct request_queue *q);
Tejun Heoc9a929d2011-10-19 14:42:16 +0200236extern void blk_throtl_release(struct request_queue *q);
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200237#else /* CONFIG_BLK_DEV_THROTTLING */
Tejun Heobc16a4f2011-10-19 14:33:01 +0200238static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200239{
Tejun Heobc16a4f2011-10-19 14:33:01 +0200240 return false;
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200241}
Tejun Heoc9a929d2011-10-19 14:42:16 +0200242static inline void blk_throtl_drain(struct request_queue *q) { }
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200243static inline int blk_throtl_init(struct request_queue *q) { return 0; }
244static inline void blk_throtl_exit(struct request_queue *q) { }
Tejun Heoc9a929d2011-10-19 14:42:16 +0200245static inline void blk_throtl_release(struct request_queue *q) { }
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200246#endif /* CONFIG_BLK_DEV_THROTTLING */
247
248#endif /* BLK_INTERNAL_H */