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 void init_request_from_bio(struct request
*req
, struct bio
*bio
);
17 void blk_rq_bio_prep(struct request_queue
*q
, struct request
*rq
,
19 int blk_rq_append_bio(struct request_queue
*q
, struct request
*rq
,
21 void blk_drain_queue(struct request_queue
*q
, bool drain_all
);
22 void blk_dequeue_request(struct request
*rq
);
23 void __blk_queue_free_tags(struct request_queue
*q
);
24 bool __blk_end_bidi_request(struct request
*rq
, int error
,
25 unsigned int nr_bytes
, unsigned int bidi_bytes
);
27 void blk_rq_timed_out_timer(unsigned long data
);
28 void blk_delete_timer(struct request
*);
29 void blk_add_timer(struct request
*);
30 void __generic_unplug_device(struct request_queue
*);
33 * Internal atomic flags for request handling
35 enum rq_atomic_flags
{
36 REQ_ATOM_COMPLETE
= 0,
40 * EH timer and IO completion will both attempt to 'grab' the request, make
41 * sure that only one of them succeeds
43 static inline int blk_mark_rq_complete(struct request
*rq
)
45 return test_and_set_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
48 static inline void blk_clear_rq_complete(struct request
*rq
)
50 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
54 * Internal elevator interface
56 #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
58 void blk_insert_flush(struct request
*rq
);
59 void blk_abort_flushes(struct request_queue
*q
);
61 static inline struct request
*__elv_next_request(struct request_queue
*q
)
66 if (!list_empty(&q
->queue_head
)) {
67 rq
= list_entry_rq(q
->queue_head
.next
);
72 * Flush request is running and flush request isn't queueable
73 * in the drive, we can hold the queue till flush request is
74 * finished. Even we don't do this, driver can't dispatch next
75 * requests and will requeue them. And this can improve
76 * throughput too. For example, we have request flush1, write1,
77 * flush 2. flush1 is dispatched, then queue is hold, write1
78 * isn't inserted to queue. After flush1 is finished, flush2
79 * will be dispatched. Since disk cache is already clean,
80 * flush2 will be finished very soon, so looks like flush2 is
82 * Since the queue is hold, a flag is set to indicate the queue
83 * should be restarted later. Please see flush_end_io() for
86 if (q
->flush_pending_idx
!= q
->flush_running_idx
&&
87 !queue_flush_queueable(q
)) {
88 q
->flush_queue_delayed
= 1;
91 if (unlikely(blk_queue_dead(q
)) ||
92 !q
->elevator
->ops
->elevator_dispatch_fn(q
, 0))
97 static inline void elv_activate_rq(struct request_queue
*q
, struct request
*rq
)
99 struct elevator_queue
*e
= q
->elevator
;
101 if (e
->ops
->elevator_activate_req_fn
)
102 e
->ops
->elevator_activate_req_fn(q
, rq
);
105 static inline void elv_deactivate_rq(struct request_queue
*q
, struct request
*rq
)
107 struct elevator_queue
*e
= q
->elevator
;
109 if (e
->ops
->elevator_deactivate_req_fn
)
110 e
->ops
->elevator_deactivate_req_fn(q
, rq
);
113 #ifdef CONFIG_FAIL_IO_TIMEOUT
114 int blk_should_fake_timeout(struct request_queue
*);
115 ssize_t
part_timeout_show(struct device
*, struct device_attribute
*, char *);
116 ssize_t
part_timeout_store(struct device
*, struct device_attribute
*,
117 const char *, size_t);
119 static inline int blk_should_fake_timeout(struct request_queue
*q
)
125 struct io_context
*current_io_context(gfp_t gfp_flags
, int node
);
127 int ll_back_merge_fn(struct request_queue
*q
, struct request
*req
,
129 int ll_front_merge_fn(struct request_queue
*q
, struct request
*req
,
131 int attempt_back_merge(struct request_queue
*q
, struct request
*rq
);
132 int attempt_front_merge(struct request_queue
*q
, struct request
*rq
);
133 int blk_attempt_req_merge(struct request_queue
*q
, struct request
*rq
,
134 struct request
*next
);
135 void blk_recalc_rq_segments(struct request
*rq
);
136 void blk_rq_set_mixed_merge(struct request
*rq
);
138 void blk_queue_congestion_threshold(struct request_queue
*q
);
140 int blk_dev_init(void);
142 void elv_quiesce_start(struct request_queue
*q
);
143 void elv_quiesce_end(struct request_queue
*q
);
147 * Return the threshold (number of used requests) at which the queue is
148 * considered to be congested. It include a little hysteresis to keep the
149 * context switch rate down.
151 static inline int queue_congestion_on_threshold(struct request_queue
*q
)
153 return q
->nr_congestion_on
;
157 * The threshold at which a queue is considered to be uncongested
159 static inline int queue_congestion_off_threshold(struct request_queue
*q
)
161 return q
->nr_congestion_off
;
164 static inline int blk_cpu_to_group(int cpu
)
167 #ifdef CONFIG_SCHED_MC
168 const struct cpumask
*mask
= cpu_coregroup_mask(cpu
);
169 group
= cpumask_first(mask
);
170 #elif defined(CONFIG_SCHED_SMT)
171 group
= cpumask_first(topology_thread_cpumask(cpu
));
175 if (likely(group
< NR_CPUS
))
181 * Contribute to IO statistics IFF:
183 * a) it's attached to a gendisk, and
184 * b) the queue had IO stats enabled when this request was started, and
185 * c) it's a file system request or a discard request
187 static inline int blk_do_io_stat(struct request
*rq
)
189 return rq
->rq_disk
&&
190 (rq
->cmd_flags
& REQ_IO_STAT
) &&
191 (rq
->cmd_type
== REQ_TYPE_FS
||
192 (rq
->cmd_flags
& REQ_DISCARD
));
195 #ifdef CONFIG_BLK_DEV_THROTTLING
196 extern bool blk_throtl_bio(struct request_queue
*q
, struct bio
*bio
);
197 extern void blk_throtl_drain(struct request_queue
*q
);
198 extern int blk_throtl_init(struct request_queue
*q
);
199 extern void blk_throtl_exit(struct request_queue
*q
);
200 extern void blk_throtl_release(struct request_queue
*q
);
201 #else /* CONFIG_BLK_DEV_THROTTLING */
202 static inline bool blk_throtl_bio(struct request_queue
*q
, struct bio
*bio
)
206 static inline void blk_throtl_drain(struct request_queue
*q
) { }
207 static inline int blk_throtl_init(struct request_queue
*q
) { return 0; }
208 static inline void blk_throtl_exit(struct request_queue
*q
) { }
209 static inline void blk_throtl_release(struct request_queue
*q
) { }
210 #endif /* CONFIG_BLK_DEV_THROTTLING */
212 #endif /* BLK_INTERNAL_H */