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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 Heod7325802012-03-05 13:14:58 -080026void blk_queue_bypass_start(struct request_queue *q);
27void blk_queue_bypass_end(struct request_queue *q);
Tejun Heo9934c8c2009-05-08 11:54:16 +090028void blk_dequeue_request(struct request *rq);
Jens Axboe8324aa92008-01-29 14:51:59 +010029void __blk_queue_free_tags(struct request_queue *q);
Jeff Moyer4853aba2011-08-15 21:37:25 +020030bool __blk_end_bidi_request(struct request *rq, int error,
31 unsigned int nr_bytes, unsigned int bidi_bytes);
Jens Axboe8324aa92008-01-29 14:51:59 +010032
Jens Axboe242f9dc2008-09-14 05:55:09 -070033void blk_rq_timed_out_timer(unsigned long data);
34void blk_delete_timer(struct request *);
35void blk_add_timer(struct request *);
Jens Axboef73e2d12008-10-17 14:03:08 +020036void __generic_unplug_device(struct request_queue *);
Jens Axboe242f9dc2008-09-14 05:55:09 -070037
38/*
39 * Internal atomic flags for request handling
40 */
41enum rq_atomic_flags {
42 REQ_ATOM_COMPLETE = 0,
43};
44
45/*
46 * EH timer and IO completion will both attempt to 'grab' the request, make
Lucas De Marchi25985ed2011-03-30 22:57:33 -030047 * sure that only one of them succeeds
Jens Axboe242f9dc2008-09-14 05:55:09 -070048 */
49static inline int blk_mark_rq_complete(struct request *rq)
50{
51 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
52}
53
54static inline void blk_clear_rq_complete(struct request *rq)
55{
56 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
57}
Jens Axboe86db1e22008-01-29 14:53:40 +010058
Tejun Heo158dbda2009-04-23 11:05:18 +090059/*
60 * Internal elevator interface
61 */
62#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
63
Tejun Heoae1b1532011-01-25 12:43:54 +010064void blk_insert_flush(struct request *rq);
65void blk_abort_flushes(struct request_queue *q);
Tejun Heodd831002010-09-03 11:56:16 +020066
Tejun Heo158dbda2009-04-23 11:05:18 +090067static inline struct request *__elv_next_request(struct request_queue *q)
68{
69 struct request *rq;
70
71 while (1) {
Tejun Heoae1b1532011-01-25 12:43:54 +010072 if (!list_empty(&q->queue_head)) {
Tejun Heo158dbda2009-04-23 11:05:18 +090073 rq = list_entry_rq(q->queue_head.next);
Tejun Heoae1b1532011-01-25 12:43:54 +010074 return rq;
Tejun Heo158dbda2009-04-23 11:05:18 +090075 }
76
shaohua.li@intel.com3ac0cc42011-05-06 11:34:41 -060077 /*
78 * Flush request is running and flush request isn't queueable
79 * in the drive, we can hold the queue till flush request is
80 * finished. Even we don't do this, driver can't dispatch next
81 * requests and will requeue them. And this can improve
82 * throughput too. For example, we have request flush1, write1,
83 * flush 2. flush1 is dispatched, then queue is hold, write1
84 * isn't inserted to queue. After flush1 is finished, flush2
85 * will be dispatched. Since disk cache is already clean,
86 * flush2 will be finished very soon, so looks like flush2 is
87 * folded to flush1.
88 * Since the queue is hold, a flag is set to indicate the queue
89 * should be restarted later. Please see flush_end_io() for
90 * details.
91 */
92 if (q->flush_pending_idx != q->flush_running_idx &&
93 !queue_flush_queueable(q)) {
94 q->flush_queue_delayed = 1;
95 return NULL;
96 }
Tejun Heo34f60552011-12-14 00:33:37 +010097 if (unlikely(blk_queue_dead(q)) ||
Tejun Heo22f746e2011-12-14 00:33:41 +010098 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
Tejun Heo158dbda2009-04-23 11:05:18 +090099 return NULL;
100 }
101}
102
103static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
104{
105 struct elevator_queue *e = q->elevator;
106
Tejun Heo22f746e2011-12-14 00:33:41 +0100107 if (e->type->ops.elevator_activate_req_fn)
108 e->type->ops.elevator_activate_req_fn(q, rq);
Tejun Heo158dbda2009-04-23 11:05:18 +0900109}
110
111static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
112{
113 struct elevator_queue *e = q->elevator;
114
Tejun Heo22f746e2011-12-14 00:33:41 +0100115 if (e->type->ops.elevator_deactivate_req_fn)
116 e->type->ops.elevator_deactivate_req_fn(q, rq);
Tejun Heo158dbda2009-04-23 11:05:18 +0900117}
118
Jens Axboe581d4e22008-09-14 05:56:33 -0700119#ifdef CONFIG_FAIL_IO_TIMEOUT
120int blk_should_fake_timeout(struct request_queue *);
121ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
122ssize_t part_timeout_store(struct device *, struct device_attribute *,
123 const char *, size_t);
124#else
125static inline int blk_should_fake_timeout(struct request_queue *q)
126{
127 return 0;
128}
129#endif
130
Jens Axboed6d48192008-01-29 14:04:06 +0100131int ll_back_merge_fn(struct request_queue *q, struct request *req,
132 struct bio *bio);
133int ll_front_merge_fn(struct request_queue *q, struct request *req,
134 struct bio *bio);
135int attempt_back_merge(struct request_queue *q, struct request *rq);
136int attempt_front_merge(struct request_queue *q, struct request *rq);
Jens Axboe5e84ea32011-03-21 10:14:27 +0100137int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
138 struct request *next);
Jens Axboed6d48192008-01-29 14:04:06 +0100139void blk_recalc_rq_segments(struct request *rq);
Tejun Heo80a761f2009-07-03 17:48:17 +0900140void blk_rq_set_mixed_merge(struct request *rq);
Tejun Heo050c8ea2012-02-08 09:19:38 +0100141bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
142int blk_try_merge(struct request *rq, struct bio *bio);
Jens Axboed6d48192008-01-29 14:04:06 +0100143
Jens Axboe8324aa92008-01-29 14:51:59 +0100144void blk_queue_congestion_threshold(struct request_queue *q);
145
Adrian Bunkff889722008-03-04 11:23:45 +0100146int blk_dev_init(void);
147
Jens Axboef253b862010-10-24 22:06:02 +0200148
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 Axboec2553b52009-04-24 08:10:11 +0200167/*
168 * Contribute to IO statistics IFF:
169 *
170 * a) it's attached to a gendisk, and
171 * b) the queue had IO stats enabled when this request was started, and
Kiyoshi Ueda3c4198e2009-05-27 14:50:02 +0200172 * c) it's a file system request or a discard request
Jens Axboec2553b52009-04-24 08:10:11 +0200173 */
Jerome Marchand26308ea2009-03-27 10:31:51 +0100174static inline int blk_do_io_stat(struct request *rq)
Jens Axboefb8ec182009-02-02 08:42:32 +0100175{
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200176 return rq->rq_disk &&
177 (rq->cmd_flags & REQ_IO_STAT) &&
178 (rq->cmd_type == REQ_TYPE_FS ||
179 (rq->cmd_flags & REQ_DISCARD));
Jens Axboefb8ec182009-02-02 08:42:32 +0100180}
181
Tejun Heof2dbd762011-12-14 00:33:40 +0100182/*
183 * Internal io_context interface
184 */
185void get_io_context(struct io_context *ioc);
Tejun Heo47fdd4c2011-12-14 00:33:42 +0100186struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
Tejun Heo24acfc32012-03-05 13:15:24 -0800187struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
188 gfp_t gfp_mask);
Tejun Heo7e5a8792011-12-14 00:33:42 +0100189void ioc_clear_queue(struct request_queue *q);
Tejun Heof2dbd762011-12-14 00:33:40 +0100190
Tejun Heo24acfc32012-03-05 13:15:24 -0800191int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
Tejun Heof2dbd762011-12-14 00:33:40 +0100192
193/**
194 * create_io_context - try to create task->io_context
Tejun Heof2dbd762011-12-14 00:33:40 +0100195 * @gfp_mask: allocation mask
196 * @node: allocation node
197 *
Tejun Heo24acfc32012-03-05 13:15:24 -0800198 * If %current->io_context is %NULL, allocate a new io_context and install
199 * it. Returns the current %current->io_context which may be %NULL if
200 * allocation failed.
Tejun Heof2dbd762011-12-14 00:33:40 +0100201 *
202 * Note that this function can't be called with IRQ disabled because
Tejun Heo24acfc32012-03-05 13:15:24 -0800203 * task_lock which protects %current->io_context is IRQ-unsafe.
Tejun Heof2dbd762011-12-14 00:33:40 +0100204 */
Tejun Heo24acfc32012-03-05 13:15:24 -0800205static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
Tejun Heof2dbd762011-12-14 00:33:40 +0100206{
207 WARN_ON_ONCE(irqs_disabled());
Tejun Heo24acfc32012-03-05 13:15:24 -0800208 if (unlikely(!current->io_context))
209 create_task_io_context(current, gfp_mask, node);
210 return current->io_context;
Tejun Heof2dbd762011-12-14 00:33:40 +0100211}
212
213/*
214 * Internal throttling interface
215 */
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200216#ifdef CONFIG_BLK_DEV_THROTTLING
Tejun Heobc16a4f2011-10-19 14:33:01 +0200217extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
Tejun Heoc9a929d2011-10-19 14:42:16 +0200218extern void blk_throtl_drain(struct request_queue *q);
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200219extern int blk_throtl_init(struct request_queue *q);
220extern void blk_throtl_exit(struct request_queue *q);
221#else /* CONFIG_BLK_DEV_THROTTLING */
Tejun Heobc16a4f2011-10-19 14:33:01 +0200222static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200223{
Tejun Heobc16a4f2011-10-19 14:33:01 +0200224 return false;
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200225}
Tejun Heoc9a929d2011-10-19 14:42:16 +0200226static inline void blk_throtl_drain(struct request_queue *q) { }
Tejun Heobc9fcbf2011-10-19 14:31:18 +0200227static inline int blk_throtl_init(struct request_queue *q) { return 0; }
228static inline void blk_throtl_exit(struct request_queue *q) { }
229#endif /* CONFIG_BLK_DEV_THROTTLING */
230
231#endif /* BLK_INTERNAL_H */