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
*);
39 void __generic_unplug_device(struct request_queue
*);
42 * Internal atomic flags for request handling
44 enum rq_atomic_flags
{
45 REQ_ATOM_COMPLETE
= 0,
49 * EH timer and IO completion will both attempt to 'grab' the request, make
50 * sure that only one of them succeeds
52 static inline int blk_mark_rq_complete(struct request
*rq
)
54 return test_and_set_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
57 static inline void blk_clear_rq_complete(struct request
*rq
)
59 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
63 * Internal elevator interface
65 #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
67 void blk_insert_flush(struct request
*rq
);
68 void blk_abort_flushes(struct request_queue
*q
);
70 static inline struct request
*__elv_next_request(struct request_queue
*q
)
75 if (!list_empty(&q
->queue_head
)) {
76 rq
= list_entry_rq(q
->queue_head
.next
);
81 * Flush request is running and flush request isn't queueable
82 * in the drive, we can hold the queue till flush request is
83 * finished. Even we don't do this, driver can't dispatch next
84 * requests and will requeue them. And this can improve
85 * throughput too. For example, we have request flush1, write1,
86 * flush 2. flush1 is dispatched, then queue is hold, write1
87 * isn't inserted to queue. After flush1 is finished, flush2
88 * will be dispatched. Since disk cache is already clean,
89 * flush2 will be finished very soon, so looks like flush2 is
91 * Since the queue is hold, a flag is set to indicate the queue
92 * should be restarted later. Please see flush_end_io() for
95 if (q
->flush_pending_idx
!= q
->flush_running_idx
&&
96 !queue_flush_queueable(q
)) {
97 q
->flush_queue_delayed
= 1;
100 if (unlikely(blk_queue_dead(q
)) ||
101 !q
->elevator
->type
->ops
.elevator_dispatch_fn(q
, 0))
106 static inline void elv_activate_rq(struct request_queue
*q
, struct request
*rq
)
108 struct elevator_queue
*e
= q
->elevator
;
110 if (e
->type
->ops
.elevator_activate_req_fn
)
111 e
->type
->ops
.elevator_activate_req_fn(q
, rq
);
114 static inline void elv_deactivate_rq(struct request_queue
*q
, struct request
*rq
)
116 struct elevator_queue
*e
= q
->elevator
;
118 if (e
->type
->ops
.elevator_deactivate_req_fn
)
119 e
->type
->ops
.elevator_deactivate_req_fn(q
, rq
);
122 #ifdef CONFIG_FAIL_IO_TIMEOUT
123 int blk_should_fake_timeout(struct request_queue
*);
124 ssize_t
part_timeout_show(struct device
*, struct device_attribute
*, char *);
125 ssize_t
part_timeout_store(struct device
*, struct device_attribute
*,
126 const char *, size_t);
128 static inline int blk_should_fake_timeout(struct request_queue
*q
)
134 int ll_back_merge_fn(struct request_queue
*q
, struct request
*req
,
136 int ll_front_merge_fn(struct request_queue
*q
, struct request
*req
,
138 int attempt_back_merge(struct request_queue
*q
, struct request
*rq
);
139 int attempt_front_merge(struct request_queue
*q
, struct request
*rq
);
140 int blk_attempt_req_merge(struct request_queue
*q
, struct request
*rq
,
141 struct request
*next
);
142 void blk_recalc_rq_segments(struct request
*rq
);
143 void blk_rq_set_mixed_merge(struct request
*rq
);
144 bool blk_rq_merge_ok(struct request
*rq
, struct bio
*bio
);
145 int blk_try_merge(struct request
*rq
, struct bio
*bio
);
147 void blk_queue_congestion_threshold(struct request_queue
*q
);
149 int blk_dev_init(void);
153 * Return the threshold (number of used requests) at which the queue is
154 * considered to be congested. It include a little hysteresis to keep the
155 * context switch rate down.
157 static inline int queue_congestion_on_threshold(struct request_queue
*q
)
159 return q
->nr_congestion_on
;
163 * The threshold at which a queue is considered to be uncongested
165 static inline int queue_congestion_off_threshold(struct request_queue
*q
)
167 return q
->nr_congestion_off
;
171 * Contribute to IO statistics IFF:
173 * a) it's attached to a gendisk, and
174 * b) the queue had IO stats enabled when this request was started, and
175 * c) it's a file system request or a discard request
177 static inline int blk_do_io_stat(struct request
*rq
)
179 return rq
->rq_disk
&&
180 (rq
->cmd_flags
& REQ_IO_STAT
) &&
181 (rq
->cmd_type
== REQ_TYPE_FS
||
182 (rq
->cmd_flags
& REQ_DISCARD
));
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 */