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 #ifdef CONFIG_DEBUG_FS
18 extern struct dentry
*blk_debugfs_root
;
21 struct blk_flush_queue
{
22 unsigned int flush_queue_delayed
:1;
23 unsigned int flush_pending_idx
:1;
24 unsigned int flush_running_idx
:1;
25 unsigned long flush_pending_since
;
26 struct list_head flush_queue
[2];
27 struct list_head flush_data_in_flight
;
28 struct request
*flush_rq
;
31 * flush_rq shares tag with this rq, both can't be active
34 struct request
*orig_rq
;
35 spinlock_t mq_flush_lock
;
38 extern struct kmem_cache
*blk_requestq_cachep
;
39 extern struct kmem_cache
*request_cachep
;
40 extern struct kobj_type blk_queue_ktype
;
41 extern struct ida blk_queue_ida
;
43 static inline struct blk_flush_queue
*blk_get_flush_queue(
44 struct request_queue
*q
, struct blk_mq_ctx
*ctx
)
47 return blk_mq_map_queue(q
, ctx
->cpu
)->fq
;
51 static inline void __blk_get_queue(struct request_queue
*q
)
53 kobject_get(&q
->kobj
);
56 struct blk_flush_queue
*blk_alloc_flush_queue(struct request_queue
*q
,
57 int node
, int cmd_size
);
58 void blk_free_flush_queue(struct blk_flush_queue
*q
);
60 int blk_init_rl(struct request_list
*rl
, struct request_queue
*q
,
62 void blk_exit_rl(struct request_queue
*q
, struct request_list
*rl
);
63 void blk_rq_bio_prep(struct request_queue
*q
, struct request
*rq
,
65 void blk_queue_bypass_start(struct request_queue
*q
);
66 void blk_queue_bypass_end(struct request_queue
*q
);
67 void blk_dequeue_request(struct request
*rq
);
68 void __blk_queue_free_tags(struct request_queue
*q
);
69 void blk_freeze_queue(struct request_queue
*q
);
71 static inline void blk_queue_enter_live(struct request_queue
*q
)
74 * Given that running in generic_make_request() context
75 * guarantees that a live reference against q_usage_counter has
76 * been established, further references under that same context
77 * need not check that the queue has been frozen (marked dead).
79 percpu_ref_get(&q
->q_usage_counter
);
82 #ifdef CONFIG_BLK_DEV_INTEGRITY
83 void blk_flush_integrity(void);
85 static inline void blk_flush_integrity(void)
90 void blk_timeout_work(struct work_struct
*work
);
91 unsigned long blk_rq_timeout(unsigned long timeout
);
92 void blk_add_timer(struct request
*req
);
93 void blk_delete_timer(struct request
*);
96 bool bio_attempt_front_merge(struct request_queue
*q
, struct request
*req
,
98 bool bio_attempt_back_merge(struct request_queue
*q
, struct request
*req
,
100 bool bio_attempt_discard_merge(struct request_queue
*q
, struct request
*req
,
102 bool blk_attempt_plug_merge(struct request_queue
*q
, struct bio
*bio
,
103 unsigned int *request_count
,
104 struct request
**same_queue_rq
);
105 unsigned int blk_plug_queued_count(struct request_queue
*q
);
107 void blk_account_io_start(struct request
*req
, bool new_io
);
108 void blk_account_io_completion(struct request
*req
, unsigned int bytes
);
109 void blk_account_io_done(struct request
*req
);
112 * Internal atomic flags for request handling
114 enum rq_atomic_flags
{
115 REQ_ATOM_COMPLETE
= 0,
121 * EH timer and IO completion will both attempt to 'grab' the request, make
122 * sure that only one of them succeeds
124 static inline int blk_mark_rq_complete(struct request
*rq
)
126 return test_and_set_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
129 static inline void blk_clear_rq_complete(struct request
*rq
)
131 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
135 * Internal elevator interface
137 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
139 void blk_insert_flush(struct request
*rq
);
141 static inline struct request
*__elv_next_request(struct request_queue
*q
)
144 struct blk_flush_queue
*fq
= blk_get_flush_queue(q
, NULL
);
146 WARN_ON_ONCE(q
->mq_ops
);
149 if (!list_empty(&q
->queue_head
)) {
150 rq
= list_entry_rq(q
->queue_head
.next
);
155 * Flush request is running and flush request isn't queueable
156 * in the drive, we can hold the queue till flush request is
157 * finished. Even we don't do this, driver can't dispatch next
158 * requests and will requeue them. And this can improve
159 * throughput too. For example, we have request flush1, write1,
160 * flush 2. flush1 is dispatched, then queue is hold, write1
161 * isn't inserted to queue. After flush1 is finished, flush2
162 * will be dispatched. Since disk cache is already clean,
163 * flush2 will be finished very soon, so looks like flush2 is
165 * Since the queue is hold, a flag is set to indicate the queue
166 * should be restarted later. Please see flush_end_io() for
169 if (fq
->flush_pending_idx
!= fq
->flush_running_idx
&&
170 !queue_flush_queueable(q
)) {
171 fq
->flush_queue_delayed
= 1;
174 if (unlikely(blk_queue_bypass(q
)) ||
175 !q
->elevator
->type
->ops
.sq
.elevator_dispatch_fn(q
, 0))
180 static inline void elv_activate_rq(struct request_queue
*q
, struct request
*rq
)
182 struct elevator_queue
*e
= q
->elevator
;
184 if (e
->type
->ops
.sq
.elevator_activate_req_fn
)
185 e
->type
->ops
.sq
.elevator_activate_req_fn(q
, rq
);
188 static inline void elv_deactivate_rq(struct request_queue
*q
, struct request
*rq
)
190 struct elevator_queue
*e
= q
->elevator
;
192 if (e
->type
->ops
.sq
.elevator_deactivate_req_fn
)
193 e
->type
->ops
.sq
.elevator_deactivate_req_fn(q
, rq
);
196 #ifdef CONFIG_FAIL_IO_TIMEOUT
197 int blk_should_fake_timeout(struct request_queue
*);
198 ssize_t
part_timeout_show(struct device
*, struct device_attribute
*, char *);
199 ssize_t
part_timeout_store(struct device
*, struct device_attribute
*,
200 const char *, size_t);
202 static inline int blk_should_fake_timeout(struct request_queue
*q
)
208 int ll_back_merge_fn(struct request_queue
*q
, struct request
*req
,
210 int ll_front_merge_fn(struct request_queue
*q
, struct request
*req
,
212 struct request
*attempt_back_merge(struct request_queue
*q
, struct request
*rq
);
213 struct request
*attempt_front_merge(struct request_queue
*q
, struct request
*rq
);
214 int blk_attempt_req_merge(struct request_queue
*q
, struct request
*rq
,
215 struct request
*next
);
216 void blk_recalc_rq_segments(struct request
*rq
);
217 void blk_rq_set_mixed_merge(struct request
*rq
);
218 bool blk_rq_merge_ok(struct request
*rq
, struct bio
*bio
);
219 enum elv_merge
blk_try_merge(struct request
*rq
, struct bio
*bio
);
221 void blk_queue_congestion_threshold(struct request_queue
*q
);
223 int blk_dev_init(void);
227 * Return the threshold (number of used requests) at which the queue is
228 * considered to be congested. It include a little hysteresis to keep the
229 * context switch rate down.
231 static inline int queue_congestion_on_threshold(struct request_queue
*q
)
233 return q
->nr_congestion_on
;
237 * The threshold at which a queue is considered to be uncongested
239 static inline int queue_congestion_off_threshold(struct request_queue
*q
)
241 return q
->nr_congestion_off
;
244 extern int blk_update_nr_requests(struct request_queue
*, unsigned int);
247 * Contribute to IO statistics IFF:
249 * a) it's attached to a gendisk, and
250 * b) the queue had IO stats enabled when this request was started, and
251 * c) it's a file system request
253 static inline int blk_do_io_stat(struct request
*rq
)
255 return rq
->rq_disk
&&
256 (rq
->rq_flags
& RQF_IO_STAT
) &&
257 !blk_rq_is_passthrough(rq
);
260 static inline void req_set_nomerge(struct request_queue
*q
, struct request
*req
)
262 req
->cmd_flags
|= REQ_NOMERGE
;
263 if (req
== q
->last_merge
)
264 q
->last_merge
= NULL
;
268 * Internal io_context interface
270 void get_io_context(struct io_context
*ioc
);
271 struct io_cq
*ioc_lookup_icq(struct io_context
*ioc
, struct request_queue
*q
);
272 struct io_cq
*ioc_create_icq(struct io_context
*ioc
, struct request_queue
*q
,
274 void ioc_clear_queue(struct request_queue
*q
);
276 int create_task_io_context(struct task_struct
*task
, gfp_t gfp_mask
, int node
);
279 * rq_ioc - determine io_context for request allocation
280 * @bio: request being allocated is for this bio (can be %NULL)
282 * Determine io_context to use for request allocation for @bio. May return
283 * %NULL if %current->io_context doesn't exist.
285 static inline struct io_context
*rq_ioc(struct bio
*bio
)
287 #ifdef CONFIG_BLK_CGROUP
288 if (bio
&& bio
->bi_ioc
)
291 return current
->io_context
;
295 * create_io_context - try to create task->io_context
296 * @gfp_mask: allocation mask
297 * @node: allocation node
299 * If %current->io_context is %NULL, allocate a new io_context and install
300 * it. Returns the current %current->io_context which may be %NULL if
303 * Note that this function can't be called with IRQ disabled because
304 * task_lock which protects %current->io_context is IRQ-unsafe.
306 static inline struct io_context
*create_io_context(gfp_t gfp_mask
, int node
)
308 WARN_ON_ONCE(irqs_disabled());
309 if (unlikely(!current
->io_context
))
310 create_task_io_context(current
, gfp_mask
, node
);
311 return current
->io_context
;
315 * Internal throttling interface
317 #ifdef CONFIG_BLK_DEV_THROTTLING
318 extern void blk_throtl_drain(struct request_queue
*q
);
319 extern int blk_throtl_init(struct request_queue
*q
);
320 extern void blk_throtl_exit(struct request_queue
*q
);
321 extern void blk_throtl_register_queue(struct request_queue
*q
);
322 #else /* CONFIG_BLK_DEV_THROTTLING */
323 static inline void blk_throtl_drain(struct request_queue
*q
) { }
324 static inline int blk_throtl_init(struct request_queue
*q
) { return 0; }
325 static inline void blk_throtl_exit(struct request_queue
*q
) { }
326 static inline void blk_throtl_register_queue(struct request_queue
*q
) { }
327 #endif /* CONFIG_BLK_DEV_THROTTLING */
328 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
329 extern ssize_t
blk_throtl_sample_time_show(struct request_queue
*q
, char *page
);
330 extern ssize_t
blk_throtl_sample_time_store(struct request_queue
*q
,
331 const char *page
, size_t count
);
332 extern void blk_throtl_bio_endio(struct bio
*bio
);
333 extern void blk_throtl_stat_add(struct request
*rq
, u64 time
);
335 static inline void blk_throtl_bio_endio(struct bio
*bio
) { }
336 static inline void blk_throtl_stat_add(struct request
*rq
, u64 time
) { }
340 extern int init_emergency_isa_pool(void);
341 extern void blk_queue_bounce(struct request_queue
*q
, struct bio
**bio
);
343 static inline int init_emergency_isa_pool(void)
347 static inline void blk_queue_bounce(struct request_queue
*q
, struct bio
**bio
)
350 #endif /* CONFIG_BOUNCE */
352 #endif /* BLK_INTERNAL_H */