6 /* Amount of time in which a process may batch requests */
7 #define BLK_BATCH_TIME (HZ/50UL)
9 /* Number of requests a "batching" process may submit */
10 #define BLK_BATCH_REQ 32
12 extern struct kmem_cache *blk_requestq_cachep;
13 extern struct kobj_type blk_queue_ktype;
14 extern struct ida blk_queue_ida;
16 static inline void __blk_get_queue(struct request_queue *q)
18 kobject_get(&q->kobj);
21 int blk_init_rl(struct request_list *rl, struct request_queue *q,
23 void blk_exit_rl(struct request_list *rl);
24 void init_request_from_bio(struct request *req, struct bio *bio);
25 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
27 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
29 void blk_queue_bypass_start(struct request_queue *q);
30 void blk_queue_bypass_end(struct request_queue *q);
31 void blk_dequeue_request(struct request *rq);
32 void __blk_queue_free_tags(struct request_queue *q);
33 bool __blk_end_bidi_request(struct request *rq, int error,
34 unsigned int nr_bytes, unsigned int bidi_bytes);
36 void blk_rq_timed_out_timer(unsigned long data);
37 void blk_delete_timer(struct request *);
38 void blk_add_timer(struct request *);
41 * Internal atomic flags for request handling
43 enum rq_atomic_flags {
44 REQ_ATOM_COMPLETE = 0,
48 * EH timer and IO completion will both attempt to 'grab' the request, make
49 * sure that only one of them succeeds
51 static inline int blk_mark_rq_complete(struct request *rq)
53 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
56 static inline void blk_clear_rq_complete(struct request *rq)
58 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
62 * Internal elevator interface
64 #define ELV_ON_HASH(rq) hash_hashed(&(rq)->hash)
66 void blk_insert_flush(struct request *rq);
67 void blk_abort_flushes(struct request_queue *q);
69 static inline struct request *__elv_next_request(struct request_queue *q)
74 if (!list_empty(&q->queue_head)) {
75 rq = list_entry_rq(q->queue_head.next);
80 * Flush request is running and flush request isn't queueable
81 * in the drive, we can hold the queue till flush request is
82 * finished. Even we don't do this, driver can't dispatch next
83 * requests and will requeue them. And this can improve
84 * throughput too. For example, we have request flush1, write1,
85 * flush 2. flush1 is dispatched, then queue is hold, write1
86 * isn't inserted to queue. After flush1 is finished, flush2
87 * will be dispatched. Since disk cache is already clean,
88 * flush2 will be finished very soon, so looks like flush2 is
90 * Since the queue is hold, a flag is set to indicate the queue
91 * should be restarted later. Please see flush_end_io() for
94 if (q->flush_pending_idx != q->flush_running_idx &&
95 !queue_flush_queueable(q)) {
96 q->flush_queue_delayed = 1;
99 if (unlikely(blk_queue_bypass(q)) ||
100 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
105 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
107 struct elevator_queue *e = q->elevator;
109 if (e->type->ops.elevator_activate_req_fn)
110 e->type->ops.elevator_activate_req_fn(q, rq);
113 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
115 struct elevator_queue *e = q->elevator;
117 if (e->type->ops.elevator_deactivate_req_fn)
118 e->type->ops.elevator_deactivate_req_fn(q, rq);
121 #ifdef CONFIG_FAIL_IO_TIMEOUT
122 int blk_should_fake_timeout(struct request_queue *);
123 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
124 ssize_t part_timeout_store(struct device *, struct device_attribute *,
125 const char *, size_t);
127 static inline int blk_should_fake_timeout(struct request_queue *q)
133 int ll_back_merge_fn(struct request_queue *q, struct request *req,
135 int ll_front_merge_fn(struct request_queue *q, struct request *req,
137 int attempt_back_merge(struct request_queue *q, struct request *rq);
138 int attempt_front_merge(struct request_queue *q, struct request *rq);
139 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
140 struct request *next);
141 void blk_recalc_rq_segments(struct request *rq);
142 void blk_rq_set_mixed_merge(struct request *rq);
143 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
144 int blk_try_merge(struct request *rq, struct bio *bio);
146 void blk_queue_congestion_threshold(struct request_queue *q);
148 void __blk_run_queue_uncond(struct request_queue *q);
150 int blk_dev_init(void);
154 * Return the threshold (number of used requests) at which the queue is
155 * considered to be congested. It include a little hysteresis to keep the
156 * context switch rate down.
158 static inline int queue_congestion_on_threshold(struct request_queue *q)
160 return q->nr_congestion_on;
164 * The threshold at which a queue is considered to be uncongested
166 static inline int queue_congestion_off_threshold(struct request_queue *q)
168 return q->nr_congestion_off;
172 * Contribute to IO statistics IFF:
174 * a) it's attached to a gendisk, and
175 * b) the queue had IO stats enabled when this request was started, and
176 * c) it's a file system request
178 static inline int blk_do_io_stat(struct request *rq)
180 return rq->rq_disk &&
181 (rq->cmd_flags & REQ_IO_STAT) &&
182 (rq->cmd_type == REQ_TYPE_FS);
186 * Internal io_context interface
188 void get_io_context(struct io_context *ioc);
189 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
190 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
192 void ioc_clear_queue(struct request_queue *q);
194 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
197 * create_io_context - try to create task->io_context
198 * @gfp_mask: allocation mask
199 * @node: allocation node
201 * If %current->io_context is %NULL, allocate a new io_context and install
202 * it. Returns the current %current->io_context which may be %NULL if
205 * Note that this function can't be called with IRQ disabled because
206 * task_lock which protects %current->io_context is IRQ-unsafe.
208 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
210 WARN_ON_ONCE(irqs_disabled());
211 if (unlikely(!current->io_context))
212 create_task_io_context(current, gfp_mask, node);
213 return current->io_context;
217 * Internal throttling interface
219 #ifdef CONFIG_BLK_DEV_THROTTLING
220 extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
221 extern void blk_throtl_drain(struct request_queue *q);
222 extern int blk_throtl_init(struct request_queue *q);
223 extern void blk_throtl_exit(struct request_queue *q);
224 #else /* CONFIG_BLK_DEV_THROTTLING */
225 static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
229 static inline void blk_throtl_drain(struct request_queue *q) { }
230 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
231 static inline void blk_throtl_exit(struct request_queue *q) { }
232 #endif /* CONFIG_BLK_DEV_THROTTLING */
234 #endif /* BLK_INTERNAL_H */