5 #include <linux/blk-mq.h>
8 /* Amount of time in which a process may batch requests */
9 #define BLK_BATCH_TIME (HZ/50UL)
11 /* Number of requests a "batching" process may submit */
12 #define BLK_BATCH_REQ 32
14 /* Max future timer expiry for timeouts */
15 #define BLK_MAX_TIMEOUT (5 * HZ)
17 struct blk_flush_queue
{
18 unsigned int flush_queue_delayed
:1;
19 unsigned int flush_pending_idx
:1;
20 unsigned int flush_running_idx
:1;
21 unsigned long flush_pending_since
;
22 struct list_head flush_queue
[2];
23 struct list_head flush_data_in_flight
;
24 struct request
*flush_rq
;
27 * flush_rq shares tag with this rq, both can't be active
30 struct request
*orig_rq
;
31 spinlock_t mq_flush_lock
;
34 extern struct kmem_cache
*blk_requestq_cachep
;
35 extern struct kmem_cache
*request_cachep
;
36 extern struct kobj_type blk_queue_ktype
;
37 extern struct ida blk_queue_ida
;
39 static inline struct blk_flush_queue
*blk_get_flush_queue(
40 struct request_queue
*q
, struct blk_mq_ctx
*ctx
)
42 struct blk_mq_hw_ctx
*hctx
;
47 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
52 static inline void __blk_get_queue(struct request_queue
*q
)
54 kobject_get(&q
->kobj
);
57 struct blk_flush_queue
*blk_alloc_flush_queue(struct request_queue
*q
,
58 int node
, int cmd_size
);
59 void blk_free_flush_queue(struct blk_flush_queue
*q
);
61 int blk_init_rl(struct request_list
*rl
, struct request_queue
*q
,
63 void blk_exit_rl(struct request_list
*rl
);
64 void init_request_from_bio(struct request
*req
, struct bio
*bio
);
65 void blk_rq_bio_prep(struct request_queue
*q
, struct request
*rq
,
67 int blk_rq_append_bio(struct request_queue
*q
, struct request
*rq
,
69 void blk_queue_bypass_start(struct request_queue
*q
);
70 void blk_queue_bypass_end(struct request_queue
*q
);
71 void blk_dequeue_request(struct request
*rq
);
72 void __blk_queue_free_tags(struct request_queue
*q
);
73 bool __blk_end_bidi_request(struct request
*rq
, int error
,
74 unsigned int nr_bytes
, unsigned int bidi_bytes
);
76 void blk_rq_timed_out_timer(unsigned long data
);
77 unsigned long blk_rq_timeout(unsigned long timeout
);
78 void blk_add_timer(struct request
*req
);
79 void blk_delete_timer(struct request
*);
82 bool bio_attempt_front_merge(struct request_queue
*q
, struct request
*req
,
84 bool bio_attempt_back_merge(struct request_queue
*q
, struct request
*req
,
86 bool blk_attempt_plug_merge(struct request_queue
*q
, struct bio
*bio
,
87 unsigned int *request_count
,
88 struct request
**same_queue_rq
);
90 void blk_account_io_start(struct request
*req
, bool new_io
);
91 void blk_account_io_completion(struct request
*req
, unsigned int bytes
);
92 void blk_account_io_done(struct request
*req
);
95 * Internal atomic flags for request handling
97 enum rq_atomic_flags
{
98 REQ_ATOM_COMPLETE
= 0,
103 * EH timer and IO completion will both attempt to 'grab' the request, make
104 * sure that only one of them succeeds
106 static inline int blk_mark_rq_complete(struct request
*rq
)
108 return test_and_set_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
111 static inline void blk_clear_rq_complete(struct request
*rq
)
113 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
117 * Internal elevator interface
119 #define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
121 void blk_insert_flush(struct request
*rq
);
123 static inline struct request
*__elv_next_request(struct request_queue
*q
)
126 struct blk_flush_queue
*fq
= blk_get_flush_queue(q
, NULL
);
129 if (!list_empty(&q
->queue_head
)) {
130 rq
= list_entry_rq(q
->queue_head
.next
);
135 * Flush request is running and flush request isn't queueable
136 * in the drive, we can hold the queue till flush request is
137 * finished. Even we don't do this, driver can't dispatch next
138 * requests and will requeue them. And this can improve
139 * throughput too. For example, we have request flush1, write1,
140 * flush 2. flush1 is dispatched, then queue is hold, write1
141 * isn't inserted to queue. After flush1 is finished, flush2
142 * will be dispatched. Since disk cache is already clean,
143 * flush2 will be finished very soon, so looks like flush2 is
145 * Since the queue is hold, a flag is set to indicate the queue
146 * should be restarted later. Please see flush_end_io() for
149 if (fq
->flush_pending_idx
!= fq
->flush_running_idx
&&
150 !queue_flush_queueable(q
)) {
151 fq
->flush_queue_delayed
= 1;
154 if (unlikely(blk_queue_bypass(q
)) ||
155 !q
->elevator
->type
->ops
.elevator_dispatch_fn(q
, 0))
160 static inline void elv_activate_rq(struct request_queue
*q
, struct request
*rq
)
162 struct elevator_queue
*e
= q
->elevator
;
164 if (e
->type
->ops
.elevator_activate_req_fn
)
165 e
->type
->ops
.elevator_activate_req_fn(q
, rq
);
168 static inline void elv_deactivate_rq(struct request_queue
*q
, struct request
*rq
)
170 struct elevator_queue
*e
= q
->elevator
;
172 if (e
->type
->ops
.elevator_deactivate_req_fn
)
173 e
->type
->ops
.elevator_deactivate_req_fn(q
, rq
);
176 #ifdef CONFIG_FAIL_IO_TIMEOUT
177 int blk_should_fake_timeout(struct request_queue
*);
178 ssize_t
part_timeout_show(struct device
*, struct device_attribute
*, char *);
179 ssize_t
part_timeout_store(struct device
*, struct device_attribute
*,
180 const char *, size_t);
182 static inline int blk_should_fake_timeout(struct request_queue
*q
)
188 int ll_back_merge_fn(struct request_queue
*q
, struct request
*req
,
190 int ll_front_merge_fn(struct request_queue
*q
, struct request
*req
,
192 int attempt_back_merge(struct request_queue
*q
, struct request
*rq
);
193 int attempt_front_merge(struct request_queue
*q
, struct request
*rq
);
194 int blk_attempt_req_merge(struct request_queue
*q
, struct request
*rq
,
195 struct request
*next
);
196 void blk_recalc_rq_segments(struct request
*rq
);
197 void blk_rq_set_mixed_merge(struct request
*rq
);
198 bool blk_rq_merge_ok(struct request
*rq
, struct bio
*bio
);
199 int blk_try_merge(struct request
*rq
, struct bio
*bio
);
201 void blk_queue_congestion_threshold(struct request_queue
*q
);
203 int blk_dev_init(void);
207 * Return the threshold (number of used requests) at which the queue is
208 * considered to be congested. It include a little hysteresis to keep the
209 * context switch rate down.
211 static inline int queue_congestion_on_threshold(struct request_queue
*q
)
213 return q
->nr_congestion_on
;
217 * The threshold at which a queue is considered to be uncongested
219 static inline int queue_congestion_off_threshold(struct request_queue
*q
)
221 return q
->nr_congestion_off
;
224 extern int blk_update_nr_requests(struct request_queue
*, unsigned int);
227 * Contribute to IO statistics IFF:
229 * a) it's attached to a gendisk, and
230 * b) the queue had IO stats enabled when this request was started, and
231 * c) it's a file system request
233 static inline int blk_do_io_stat(struct request
*rq
)
235 return rq
->rq_disk
&&
236 (rq
->cmd_flags
& REQ_IO_STAT
) &&
237 (rq
->cmd_type
== REQ_TYPE_FS
);
241 * Internal io_context interface
243 void get_io_context(struct io_context
*ioc
);
244 struct io_cq
*ioc_lookup_icq(struct io_context
*ioc
, struct request_queue
*q
);
245 struct io_cq
*ioc_create_icq(struct io_context
*ioc
, struct request_queue
*q
,
247 void ioc_clear_queue(struct request_queue
*q
);
249 int create_task_io_context(struct task_struct
*task
, gfp_t gfp_mask
, int node
);
252 * create_io_context - try to create task->io_context
253 * @gfp_mask: allocation mask
254 * @node: allocation node
256 * If %current->io_context is %NULL, allocate a new io_context and install
257 * it. Returns the current %current->io_context which may be %NULL if
260 * Note that this function can't be called with IRQ disabled because
261 * task_lock which protects %current->io_context is IRQ-unsafe.
263 static inline struct io_context
*create_io_context(gfp_t gfp_mask
, int node
)
265 WARN_ON_ONCE(irqs_disabled());
266 if (unlikely(!current
->io_context
))
267 create_task_io_context(current
, gfp_mask
, node
);
268 return current
->io_context
;
272 * Internal throttling interface
274 #ifdef CONFIG_BLK_DEV_THROTTLING
275 extern void blk_throtl_drain(struct request_queue
*q
);
276 extern int blk_throtl_init(struct request_queue
*q
);
277 extern void blk_throtl_exit(struct request_queue
*q
);
278 #else /* CONFIG_BLK_DEV_THROTTLING */
279 static inline void blk_throtl_drain(struct request_queue
*q
) { }
280 static inline int blk_throtl_init(struct request_queue
*q
) { return 0; }
281 static inline void blk_throtl_exit(struct request_queue
*q
) { }
282 #endif /* CONFIG_BLK_DEV_THROTTLING */
284 #endif /* BLK_INTERNAL_H */