4 /* Amount of time in which a process may batch requests */
5 #define BLK_BATCH_TIME (HZ/50UL)
7 /* Number of requests a "batching" process may submit */
8 #define BLK_BATCH_REQ 32
10 extern struct kmem_cache *blk_requestq_cachep;
11 extern struct kobj_type blk_queue_ktype;
13 void init_request_from_bio(struct request *req, struct bio *bio);
14 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
16 void blk_dequeue_request(struct request *rq);
17 void __blk_queue_free_tags(struct request_queue *q);
19 void blk_unplug_work(struct work_struct *work);
20 void blk_unplug_timeout(unsigned long data);
21 void blk_rq_timed_out_timer(unsigned long data);
22 void blk_delete_timer(struct request *);
23 void blk_add_timer(struct request *);
24 void __generic_unplug_device(struct request_queue *);
27 * Internal atomic flags for request handling
29 enum rq_atomic_flags {
30 REQ_ATOM_COMPLETE = 0,
34 * EH timer and IO completion will both attempt to 'grab' the request, make
35 * sure that only one of them suceeds
37 static inline int blk_mark_rq_complete(struct request *rq)
39 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
42 static inline void blk_clear_rq_complete(struct request *rq)
44 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
48 * Internal elevator interface
50 #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
52 static inline struct request *__elv_next_request(struct request_queue *q)
57 while (!list_empty(&q->queue_head)) {
58 rq = list_entry_rq(q->queue_head.next);
59 if (blk_do_ordered(q, &rq))
63 if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
68 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
70 struct elevator_queue *e = q->elevator;
72 if (e->ops->elevator_activate_req_fn)
73 e->ops->elevator_activate_req_fn(q, rq);
76 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
78 struct elevator_queue *e = q->elevator;
80 if (e->ops->elevator_deactivate_req_fn)
81 e->ops->elevator_deactivate_req_fn(q, rq);
84 #ifdef CONFIG_FAIL_IO_TIMEOUT
85 int blk_should_fake_timeout(struct request_queue *);
86 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
87 ssize_t part_timeout_store(struct device *, struct device_attribute *,
88 const char *, size_t);
90 static inline int blk_should_fake_timeout(struct request_queue *q)
96 struct io_context *current_io_context(gfp_t gfp_flags, int node);
98 int ll_back_merge_fn(struct request_queue *q, struct request *req,
100 int ll_front_merge_fn(struct request_queue *q, struct request *req,
102 int attempt_back_merge(struct request_queue *q, struct request *rq);
103 int attempt_front_merge(struct request_queue *q, struct request *rq);
104 void blk_recalc_rq_segments(struct request *rq);
106 void blk_queue_congestion_threshold(struct request_queue *q);
108 int blk_dev_init(void);
110 void elv_quiesce_start(struct request_queue *q);
111 void elv_quiesce_end(struct request_queue *q);
115 * Return the threshold (number of used requests) at which the queue is
116 * considered to be congested. It include a little hysteresis to keep the
117 * context switch rate down.
119 static inline int queue_congestion_on_threshold(struct request_queue *q)
121 return q->nr_congestion_on;
125 * The threshold at which a queue is considered to be uncongested
127 static inline int queue_congestion_off_threshold(struct request_queue *q)
129 return q->nr_congestion_off;
132 #if defined(CONFIG_BLK_DEV_INTEGRITY)
134 #define rq_for_each_integrity_segment(bvl, _rq, _iter) \
135 __rq_for_each_bio(_iter.bio, _rq) \
136 bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
138 #endif /* BLK_DEV_INTEGRITY */
140 static inline int blk_cpu_to_group(int cpu)
142 #ifdef CONFIG_SCHED_MC
143 const struct cpumask *mask = cpu_coregroup_mask(cpu);
144 return cpumask_first(mask);
145 #elif defined(CONFIG_SCHED_SMT)
146 return cpumask_first(topology_thread_cpumask(cpu));
153 * Contribute to IO statistics IFF:
155 * a) it's attached to a gendisk, and
156 * b) the queue had IO stats enabled when this request was started, and
157 * c) it's a file system request
159 static inline int blk_do_io_stat(struct request *rq)
161 return rq->rq_disk && blk_rq_io_stat(rq) && blk_fs_request(rq) &&