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_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);
147 if (!list_empty(&q->queue_head)) {
148 rq = list_entry_rq(q->queue_head.next);
153 * Flush request is running and flush request isn't queueable
154 * in the drive, we can hold the queue till flush request is
155 * finished. Even we don't do this, driver can't dispatch next
156 * requests and will requeue them. And this can improve
157 * throughput too. For example, we have request flush1, write1,
158 * flush 2. flush1 is dispatched, then queue is hold, write1
159 * isn't inserted to queue. After flush1 is finished, flush2
160 * will be dispatched. Since disk cache is already clean,
161 * flush2 will be finished very soon, so looks like flush2 is
163 * Since the queue is hold, a flag is set to indicate the queue
164 * should be restarted later. Please see flush_end_io() for
167 if (fq->flush_pending_idx != fq->flush_running_idx &&
168 !queue_flush_queueable(q)) {
169 fq->flush_queue_delayed = 1;
172 if (unlikely(blk_queue_bypass(q)) ||
173 !q->elevator->type->ops.sq.elevator_dispatch_fn(q, 0))
178 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
180 struct elevator_queue *e = q->elevator;
182 if (e->type->ops.sq.elevator_activate_req_fn)
183 e->type->ops.sq.elevator_activate_req_fn(q, rq);
186 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
188 struct elevator_queue *e = q->elevator;
190 if (e->type->ops.sq.elevator_deactivate_req_fn)
191 e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
194 #ifdef CONFIG_FAIL_IO_TIMEOUT
195 int blk_should_fake_timeout(struct request_queue *);
196 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
197 ssize_t part_timeout_store(struct device *, struct device_attribute *,
198 const char *, size_t);
200 static inline int blk_should_fake_timeout(struct request_queue *q)
206 int ll_back_merge_fn(struct request_queue *q, struct request *req,
208 int ll_front_merge_fn(struct request_queue *q, struct request *req,
210 struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
211 struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
212 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
213 struct request *next);
214 void blk_recalc_rq_segments(struct request *rq);
215 void blk_rq_set_mixed_merge(struct request *rq);
216 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
217 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
219 void blk_queue_congestion_threshold(struct request_queue *q);
221 int blk_dev_init(void);
225 * Return the threshold (number of used requests) at which the queue is
226 * considered to be congested. It include a little hysteresis to keep the
227 * context switch rate down.
229 static inline int queue_congestion_on_threshold(struct request_queue *q)
231 return q->nr_congestion_on;
235 * The threshold at which a queue is considered to be uncongested
237 static inline int queue_congestion_off_threshold(struct request_queue *q)
239 return q->nr_congestion_off;
242 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
245 * Contribute to IO statistics IFF:
247 * a) it's attached to a gendisk, and
248 * b) the queue had IO stats enabled when this request was started, and
249 * c) it's a file system request
251 static inline int blk_do_io_stat(struct request *rq)
253 return rq->rq_disk &&
254 (rq->rq_flags & RQF_IO_STAT) &&
255 !blk_rq_is_passthrough(rq);
258 static inline void req_set_nomerge(struct request_queue *q, struct request *req)
260 req->cmd_flags |= REQ_NOMERGE;
261 if (req == q->last_merge)
262 q->last_merge = NULL;
266 * Internal io_context interface
268 void get_io_context(struct io_context *ioc);
269 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
270 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
272 void ioc_clear_queue(struct request_queue *q);
274 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
277 * rq_ioc - determine io_context for request allocation
278 * @bio: request being allocated is for this bio (can be %NULL)
280 * Determine io_context to use for request allocation for @bio. May return
281 * %NULL if %current->io_context doesn't exist.
283 static inline struct io_context *rq_ioc(struct bio *bio)
285 #ifdef CONFIG_BLK_CGROUP
286 if (bio && bio->bi_ioc)
289 return current->io_context;
293 * create_io_context - try to create task->io_context
294 * @gfp_mask: allocation mask
295 * @node: allocation node
297 * If %current->io_context is %NULL, allocate a new io_context and install
298 * it. Returns the current %current->io_context which may be %NULL if
301 * Note that this function can't be called with IRQ disabled because
302 * task_lock which protects %current->io_context is IRQ-unsafe.
304 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
306 WARN_ON_ONCE(irqs_disabled());
307 if (unlikely(!current->io_context))
308 create_task_io_context(current, gfp_mask, node);
309 return current->io_context;
313 * Internal throttling interface
315 #ifdef CONFIG_BLK_DEV_THROTTLING
316 extern void blk_throtl_drain(struct request_queue *q);
317 extern int blk_throtl_init(struct request_queue *q);
318 extern void blk_throtl_exit(struct request_queue *q);
319 extern void blk_throtl_register_queue(struct request_queue *q);
320 #else /* CONFIG_BLK_DEV_THROTTLING */
321 static inline void blk_throtl_drain(struct request_queue *q) { }
322 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
323 static inline void blk_throtl_exit(struct request_queue *q) { }
324 static inline void blk_throtl_register_queue(struct request_queue *q) { }
325 #endif /* CONFIG_BLK_DEV_THROTTLING */
326 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
327 extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
328 extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
329 const char *page, size_t count);
330 extern void blk_throtl_bio_endio(struct bio *bio);
331 extern void blk_throtl_stat_add(struct request *rq, u64 time);
333 static inline void blk_throtl_bio_endio(struct bio *bio) { }
334 static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
337 #endif /* BLK_INTERNAL_H */