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 /* Max future timer expiry for timeouts */
13 #define BLK_MAX_TIMEOUT (5 * HZ)
15 extern struct kmem_cache
*blk_requestq_cachep
;
16 extern struct kmem_cache
*request_cachep
;
17 extern struct kobj_type blk_queue_ktype
;
18 extern struct ida blk_queue_ida
;
20 static inline void __blk_get_queue(struct request_queue
*q
)
22 kobject_get(&q
->kobj
);
25 int blk_init_rl(struct request_list
*rl
, struct request_queue
*q
,
27 void blk_exit_rl(struct request_list
*rl
);
28 void init_request_from_bio(struct request
*req
, struct bio
*bio
);
29 void blk_rq_bio_prep(struct request_queue
*q
, struct request
*rq
,
31 int blk_rq_append_bio(struct request_queue
*q
, struct request
*rq
,
33 void blk_queue_bypass_start(struct request_queue
*q
);
34 void blk_queue_bypass_end(struct request_queue
*q
);
35 void blk_dequeue_request(struct request
*rq
);
36 void __blk_queue_free_tags(struct request_queue
*q
);
37 bool __blk_end_bidi_request(struct request
*rq
, int error
,
38 unsigned int nr_bytes
, unsigned int bidi_bytes
);
40 void blk_rq_timed_out_timer(unsigned long data
);
41 void blk_rq_check_expired(struct request
*rq
, unsigned long *next_timeout
,
42 unsigned int *next_set
);
43 unsigned long blk_rq_timeout(unsigned long timeout
);
44 void blk_add_timer(struct request
*req
);
45 void blk_delete_timer(struct request
*);
48 bool bio_attempt_front_merge(struct request_queue
*q
, struct request
*req
,
50 bool bio_attempt_back_merge(struct request_queue
*q
, struct request
*req
,
52 bool blk_attempt_plug_merge(struct request_queue
*q
, struct bio
*bio
,
53 unsigned int *request_count
);
55 void blk_account_io_start(struct request
*req
, bool new_io
);
56 void blk_account_io_completion(struct request
*req
, unsigned int bytes
);
57 void blk_account_io_done(struct request
*req
);
60 * Internal atomic flags for request handling
62 enum rq_atomic_flags
{
63 REQ_ATOM_COMPLETE
= 0,
68 * EH timer and IO completion will both attempt to 'grab' the request, make
69 * sure that only one of them succeeds
71 static inline int blk_mark_rq_complete(struct request
*rq
)
73 return test_and_set_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
76 static inline void blk_clear_rq_complete(struct request
*rq
)
78 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
82 * Internal elevator interface
84 #define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
86 void blk_insert_flush(struct request
*rq
);
87 void blk_abort_flushes(struct request_queue
*q
);
89 static inline struct request
*__elv_next_request(struct request_queue
*q
)
94 if (!list_empty(&q
->queue_head
)) {
95 rq
= list_entry_rq(q
->queue_head
.next
);
100 * Flush request is running and flush request isn't queueable
101 * in the drive, we can hold the queue till flush request is
102 * finished. Even we don't do this, driver can't dispatch next
103 * requests and will requeue them. And this can improve
104 * throughput too. For example, we have request flush1, write1,
105 * flush 2. flush1 is dispatched, then queue is hold, write1
106 * isn't inserted to queue. After flush1 is finished, flush2
107 * will be dispatched. Since disk cache is already clean,
108 * flush2 will be finished very soon, so looks like flush2 is
110 * Since the queue is hold, a flag is set to indicate the queue
111 * should be restarted later. Please see flush_end_io() for
114 if (q
->flush_pending_idx
!= q
->flush_running_idx
&&
115 !queue_flush_queueable(q
)) {
116 q
->flush_queue_delayed
= 1;
119 if (unlikely(blk_queue_bypass(q
)) ||
120 !q
->elevator
->type
->ops
.elevator_dispatch_fn(q
, 0))
125 static inline void elv_activate_rq(struct request_queue
*q
, struct request
*rq
)
127 struct elevator_queue
*e
= q
->elevator
;
129 if (e
->type
->ops
.elevator_activate_req_fn
)
130 e
->type
->ops
.elevator_activate_req_fn(q
, rq
);
133 static inline void elv_deactivate_rq(struct request_queue
*q
, struct request
*rq
)
135 struct elevator_queue
*e
= q
->elevator
;
137 if (e
->type
->ops
.elevator_deactivate_req_fn
)
138 e
->type
->ops
.elevator_deactivate_req_fn(q
, rq
);
141 #ifdef CONFIG_FAIL_IO_TIMEOUT
142 int blk_should_fake_timeout(struct request_queue
*);
143 ssize_t
part_timeout_show(struct device
*, struct device_attribute
*, char *);
144 ssize_t
part_timeout_store(struct device
*, struct device_attribute
*,
145 const char *, size_t);
147 static inline int blk_should_fake_timeout(struct request_queue
*q
)
153 int ll_back_merge_fn(struct request_queue
*q
, struct request
*req
,
155 int ll_front_merge_fn(struct request_queue
*q
, struct request
*req
,
157 int attempt_back_merge(struct request_queue
*q
, struct request
*rq
);
158 int attempt_front_merge(struct request_queue
*q
, struct request
*rq
);
159 int blk_attempt_req_merge(struct request_queue
*q
, struct request
*rq
,
160 struct request
*next
);
161 void blk_recalc_rq_segments(struct request
*rq
);
162 void blk_rq_set_mixed_merge(struct request
*rq
);
163 bool blk_rq_merge_ok(struct request
*rq
, struct bio
*bio
);
164 int blk_try_merge(struct request
*rq
, struct bio
*bio
);
166 void blk_queue_congestion_threshold(struct request_queue
*q
);
168 void __blk_run_queue_uncond(struct request_queue
*q
);
170 int blk_dev_init(void);
174 * Return the threshold (number of used requests) at which the queue is
175 * considered to be congested. It include a little hysteresis to keep the
176 * context switch rate down.
178 static inline int queue_congestion_on_threshold(struct request_queue
*q
)
180 return q
->nr_congestion_on
;
184 * The threshold at which a queue is considered to be uncongested
186 static inline int queue_congestion_off_threshold(struct request_queue
*q
)
188 return q
->nr_congestion_off
;
191 extern int blk_update_nr_requests(struct request_queue
*, unsigned int);
194 * Contribute to IO statistics IFF:
196 * a) it's attached to a gendisk, and
197 * b) the queue had IO stats enabled when this request was started, and
198 * c) it's a file system request
200 static inline int blk_do_io_stat(struct request
*rq
)
202 return rq
->rq_disk
&&
203 (rq
->cmd_flags
& REQ_IO_STAT
) &&
204 (rq
->cmd_type
== REQ_TYPE_FS
);
208 * Internal io_context interface
210 void get_io_context(struct io_context
*ioc
);
211 struct io_cq
*ioc_lookup_icq(struct io_context
*ioc
, struct request_queue
*q
);
212 struct io_cq
*ioc_create_icq(struct io_context
*ioc
, struct request_queue
*q
,
214 void ioc_clear_queue(struct request_queue
*q
);
216 int create_task_io_context(struct task_struct
*task
, gfp_t gfp_mask
, int node
);
219 * create_io_context - try to create task->io_context
220 * @gfp_mask: allocation mask
221 * @node: allocation node
223 * If %current->io_context is %NULL, allocate a new io_context and install
224 * it. Returns the current %current->io_context which may be %NULL if
227 * Note that this function can't be called with IRQ disabled because
228 * task_lock which protects %current->io_context is IRQ-unsafe.
230 static inline struct io_context
*create_io_context(gfp_t gfp_mask
, int node
)
232 WARN_ON_ONCE(irqs_disabled());
233 if (unlikely(!current
->io_context
))
234 create_task_io_context(current
, gfp_mask
, node
);
235 return current
->io_context
;
239 * Internal throttling interface
241 #ifdef CONFIG_BLK_DEV_THROTTLING
242 extern bool blk_throtl_bio(struct request_queue
*q
, struct bio
*bio
);
243 extern void blk_throtl_drain(struct request_queue
*q
);
244 extern int blk_throtl_init(struct request_queue
*q
);
245 extern void blk_throtl_exit(struct request_queue
*q
);
246 #else /* CONFIG_BLK_DEV_THROTTLING */
247 static inline bool blk_throtl_bio(struct request_queue
*q
, struct bio
*bio
)
251 static inline void blk_throtl_drain(struct request_queue
*q
) { }
252 static inline int blk_throtl_init(struct request_queue
*q
) { return 0; }
253 static inline void blk_throtl_exit(struct request_queue
*q
) { }
254 #endif /* CONFIG_BLK_DEV_THROTTLING */
256 #endif /* BLK_INTERNAL_H */