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);
89 unsigned int blk_plug_queued_count(struct request_queue *q);
91 void blk_account_io_start(struct request *req, bool new_io);
92 void blk_account_io_completion(struct request *req, unsigned int bytes);
93 void blk_account_io_done(struct request *req);
96 * Internal atomic flags for request handling
98 enum rq_atomic_flags {
99 REQ_ATOM_COMPLETE = 0,
104 * EH timer and IO completion will both attempt to 'grab' the request, make
105 * sure that only one of them succeeds
107 static inline int blk_mark_rq_complete(struct request *rq)
109 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
112 static inline void blk_clear_rq_complete(struct request *rq)
114 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
118 * Internal elevator interface
120 #define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
122 void blk_insert_flush(struct request *rq);
124 static inline struct request *__elv_next_request(struct request_queue *q)
127 struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
130 if (!list_empty(&q->queue_head)) {
131 rq = list_entry_rq(q->queue_head.next);
136 * Flush request is running and flush request isn't queueable
137 * in the drive, we can hold the queue till flush request is
138 * finished. Even we don't do this, driver can't dispatch next
139 * requests and will requeue them. And this can improve
140 * throughput too. For example, we have request flush1, write1,
141 * flush 2. flush1 is dispatched, then queue is hold, write1
142 * isn't inserted to queue. After flush1 is finished, flush2
143 * will be dispatched. Since disk cache is already clean,
144 * flush2 will be finished very soon, so looks like flush2 is
146 * Since the queue is hold, a flag is set to indicate the queue
147 * should be restarted later. Please see flush_end_io() for
150 if (fq->flush_pending_idx != fq->flush_running_idx &&
151 !queue_flush_queueable(q)) {
152 fq->flush_queue_delayed = 1;
155 if (unlikely(blk_queue_bypass(q)) ||
156 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
161 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
163 struct elevator_queue *e = q->elevator;
165 if (e->type->ops.elevator_activate_req_fn)
166 e->type->ops.elevator_activate_req_fn(q, rq);
169 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
171 struct elevator_queue *e = q->elevator;
173 if (e->type->ops.elevator_deactivate_req_fn)
174 e->type->ops.elevator_deactivate_req_fn(q, rq);
177 #ifdef CONFIG_FAIL_IO_TIMEOUT
178 int blk_should_fake_timeout(struct request_queue *);
179 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
180 ssize_t part_timeout_store(struct device *, struct device_attribute *,
181 const char *, size_t);
183 static inline int blk_should_fake_timeout(struct request_queue *q)
189 int ll_back_merge_fn(struct request_queue *q, struct request *req,
191 int ll_front_merge_fn(struct request_queue *q, struct request *req,
193 int attempt_back_merge(struct request_queue *q, struct request *rq);
194 int attempt_front_merge(struct request_queue *q, struct request *rq);
195 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
196 struct request *next);
197 void blk_recalc_rq_segments(struct request *rq);
198 void blk_rq_set_mixed_merge(struct request *rq);
199 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
200 int blk_try_merge(struct request *rq, struct bio *bio);
202 void blk_queue_congestion_threshold(struct request_queue *q);
204 int blk_dev_init(void);
208 * Return the threshold (number of used requests) at which the queue is
209 * considered to be congested. It include a little hysteresis to keep the
210 * context switch rate down.
212 static inline int queue_congestion_on_threshold(struct request_queue *q)
214 return q->nr_congestion_on;
218 * The threshold at which a queue is considered to be uncongested
220 static inline int queue_congestion_off_threshold(struct request_queue *q)
222 return q->nr_congestion_off;
225 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
228 * Contribute to IO statistics IFF:
230 * a) it's attached to a gendisk, and
231 * b) the queue had IO stats enabled when this request was started, and
232 * c) it's a file system request
234 static inline int blk_do_io_stat(struct request *rq)
236 return rq->rq_disk &&
237 (rq->cmd_flags & REQ_IO_STAT) &&
238 (rq->cmd_type == REQ_TYPE_FS);
242 * Internal io_context interface
244 void get_io_context(struct io_context *ioc);
245 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
246 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
248 void ioc_clear_queue(struct request_queue *q);
250 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
253 * create_io_context - try to create task->io_context
254 * @gfp_mask: allocation mask
255 * @node: allocation node
257 * If %current->io_context is %NULL, allocate a new io_context and install
258 * it. Returns the current %current->io_context which may be %NULL if
261 * Note that this function can't be called with IRQ disabled because
262 * task_lock which protects %current->io_context is IRQ-unsafe.
264 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
266 WARN_ON_ONCE(irqs_disabled());
267 if (unlikely(!current->io_context))
268 create_task_io_context(current, gfp_mask, node);
269 return current->io_context;
273 * Internal throttling interface
275 #ifdef CONFIG_BLK_DEV_THROTTLING
276 extern void blk_throtl_drain(struct request_queue *q);
277 extern int blk_throtl_init(struct request_queue *q);
278 extern void blk_throtl_exit(struct request_queue *q);
279 #else /* CONFIG_BLK_DEV_THROTTLING */
280 static inline void blk_throtl_drain(struct request_queue *q) { }
281 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
282 static inline void blk_throtl_exit(struct request_queue *q) { }
283 #endif /* CONFIG_BLK_DEV_THROTTLING */
285 #endif /* BLK_INTERNAL_H */