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)
43 return blk_mq_map_queue(q, ctx->cpu)->fq;
47 static inline void __blk_get_queue(struct request_queue *q)
49 kobject_get(&q->kobj);
52 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
53 int node, int cmd_size);
54 void blk_free_flush_queue(struct blk_flush_queue *q);
56 int blk_init_rl(struct request_list *rl, struct request_queue *q,
58 void blk_exit_rl(struct request_list *rl);
59 void init_request_from_bio(struct request *req, struct bio *bio);
60 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
62 void blk_queue_bypass_start(struct request_queue *q);
63 void blk_queue_bypass_end(struct request_queue *q);
64 void blk_dequeue_request(struct request *rq);
65 void __blk_queue_free_tags(struct request_queue *q);
66 bool __blk_end_bidi_request(struct request *rq, int error,
67 unsigned int nr_bytes, unsigned int bidi_bytes);
68 void blk_freeze_queue(struct request_queue *q);
70 static inline void blk_queue_enter_live(struct request_queue *q)
73 * Given that running in generic_make_request() context
74 * guarantees that a live reference against q_usage_counter has
75 * been established, further references under that same context
76 * need not check that the queue has been frozen (marked dead).
78 percpu_ref_get(&q->q_usage_counter);
81 #ifdef CONFIG_BLK_DEV_INTEGRITY
82 void blk_flush_integrity(void);
84 static inline void blk_flush_integrity(void)
89 void blk_timeout_work(struct work_struct *work);
90 unsigned long blk_rq_timeout(unsigned long timeout);
91 void blk_add_timer(struct request *req);
92 void blk_delete_timer(struct request *);
95 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
97 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
99 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
100 unsigned int *request_count,
101 struct request **same_queue_rq);
102 unsigned int blk_plug_queued_count(struct request_queue *q);
104 void blk_account_io_start(struct request *req, bool new_io);
105 void blk_account_io_completion(struct request *req, unsigned int bytes);
106 void blk_account_io_done(struct request *req);
109 * Internal atomic flags for request handling
111 enum rq_atomic_flags {
112 REQ_ATOM_COMPLETE = 0,
118 * EH timer and IO completion will both attempt to 'grab' the request, make
119 * sure that only one of them succeeds
121 static inline int blk_mark_rq_complete(struct request *rq)
123 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
126 static inline void blk_clear_rq_complete(struct request *rq)
128 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
132 * Internal elevator interface
134 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
136 void blk_insert_flush(struct request *rq);
138 static inline struct request *__elv_next_request(struct request_queue *q)
141 struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
144 if (!list_empty(&q->queue_head)) {
145 rq = list_entry_rq(q->queue_head.next);
150 * Flush request is running and flush request isn't queueable
151 * in the drive, we can hold the queue till flush request is
152 * finished. Even we don't do this, driver can't dispatch next
153 * requests and will requeue them. And this can improve
154 * throughput too. For example, we have request flush1, write1,
155 * flush 2. flush1 is dispatched, then queue is hold, write1
156 * isn't inserted to queue. After flush1 is finished, flush2
157 * will be dispatched. Since disk cache is already clean,
158 * flush2 will be finished very soon, so looks like flush2 is
160 * Since the queue is hold, a flag is set to indicate the queue
161 * should be restarted later. Please see flush_end_io() for
164 if (fq->flush_pending_idx != fq->flush_running_idx &&
165 !queue_flush_queueable(q)) {
166 fq->flush_queue_delayed = 1;
169 if (unlikely(blk_queue_bypass(q)) ||
170 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
175 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
177 struct elevator_queue *e = q->elevator;
179 if (e->type->ops.elevator_activate_req_fn)
180 e->type->ops.elevator_activate_req_fn(q, rq);
183 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
185 struct elevator_queue *e = q->elevator;
187 if (e->type->ops.elevator_deactivate_req_fn)
188 e->type->ops.elevator_deactivate_req_fn(q, rq);
191 #ifdef CONFIG_FAIL_IO_TIMEOUT
192 int blk_should_fake_timeout(struct request_queue *);
193 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
194 ssize_t part_timeout_store(struct device *, struct device_attribute *,
195 const char *, size_t);
197 static inline int blk_should_fake_timeout(struct request_queue *q)
203 int ll_back_merge_fn(struct request_queue *q, struct request *req,
205 int ll_front_merge_fn(struct request_queue *q, struct request *req,
207 int attempt_back_merge(struct request_queue *q, struct request *rq);
208 int attempt_front_merge(struct request_queue *q, struct request *rq);
209 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
210 struct request *next);
211 void blk_recalc_rq_segments(struct request *rq);
212 void blk_rq_set_mixed_merge(struct request *rq);
213 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
214 int blk_try_merge(struct request *rq, struct bio *bio);
216 void blk_queue_congestion_threshold(struct request_queue *q);
218 int blk_dev_init(void);
222 * Return the threshold (number of used requests) at which the queue is
223 * considered to be congested. It include a little hysteresis to keep the
224 * context switch rate down.
226 static inline int queue_congestion_on_threshold(struct request_queue *q)
228 return q->nr_congestion_on;
232 * The threshold at which a queue is considered to be uncongested
234 static inline int queue_congestion_off_threshold(struct request_queue *q)
236 return q->nr_congestion_off;
239 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
242 * Contribute to IO statistics IFF:
244 * a) it's attached to a gendisk, and
245 * b) the queue had IO stats enabled when this request was started, and
246 * c) it's a file system request
248 static inline int blk_do_io_stat(struct request *rq)
250 return rq->rq_disk &&
251 (rq->rq_flags & RQF_IO_STAT) &&
252 (rq->cmd_type == REQ_TYPE_FS);
256 * Internal io_context interface
258 void get_io_context(struct io_context *ioc);
259 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
260 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
262 void ioc_clear_queue(struct request_queue *q);
264 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
267 * create_io_context - try to create task->io_context
268 * @gfp_mask: allocation mask
269 * @node: allocation node
271 * If %current->io_context is %NULL, allocate a new io_context and install
272 * it. Returns the current %current->io_context which may be %NULL if
275 * Note that this function can't be called with IRQ disabled because
276 * task_lock which protects %current->io_context is IRQ-unsafe.
278 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
280 WARN_ON_ONCE(irqs_disabled());
281 if (unlikely(!current->io_context))
282 create_task_io_context(current, gfp_mask, node);
283 return current->io_context;
287 * Internal throttling interface
289 #ifdef CONFIG_BLK_DEV_THROTTLING
290 extern void blk_throtl_drain(struct request_queue *q);
291 extern int blk_throtl_init(struct request_queue *q);
292 extern void blk_throtl_exit(struct request_queue *q);
293 #else /* CONFIG_BLK_DEV_THROTTLING */
294 static inline void blk_throtl_drain(struct request_queue *q) { }
295 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
296 static inline void blk_throtl_exit(struct request_queue *q) { }
297 #endif /* CONFIG_BLK_DEV_THROTTLING */
299 #endif /* BLK_INTERNAL_H */