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1 #ifndef BLK_INTERNAL_H
2 #define BLK_INTERNAL_H
3 
4 #include <linux/idr.h>
5 #include <linux/blk-mq.h>
6 #include "blk-mq.h"
7 
8 /* Amount of time in which a process may batch requests */
9 #define BLK_BATCH_TIME	(HZ/50UL)
10 
11 /* Number of requests a "batching" process may submit */
12 #define BLK_BATCH_REQ	32
13 
14 /* Max future timer expiry for timeouts */
15 #define BLK_MAX_TIMEOUT		(5 * HZ)
16 
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;
25 
26 	/*
27 	 * flush_rq shares tag with this rq, both can't be active
28 	 * at the same time
29 	 */
30 	struct request		*orig_rq;
31 	spinlock_t		mq_flush_lock;
32 };
33 
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;
38 
blk_get_flush_queue(struct request_queue * q,struct blk_mq_ctx * ctx)39 static inline struct blk_flush_queue *blk_get_flush_queue(
40 		struct request_queue *q, struct blk_mq_ctx *ctx)
41 {
42 	struct blk_mq_hw_ctx *hctx;
43 
44 	if (!q->mq_ops)
45 		return q->fq;
46 
47 	hctx = q->mq_ops->map_queue(q, ctx->cpu);
48 
49 	return hctx->fq;
50 }
51 
__blk_get_queue(struct request_queue * q)52 static inline void __blk_get_queue(struct request_queue *q)
53 {
54 	kobject_get(&q->kobj);
55 }
56 
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);
60 
61 int blk_init_rl(struct request_list *rl, struct request_queue *q,
62 		gfp_t gfp_mask);
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,
66 			struct bio *bio);
67 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
68 		      struct bio *bio);
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);
75 
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 *);
80 
81 
82 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
83 			     struct bio *bio);
84 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
85 			    struct bio *bio);
86 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
87 			    unsigned int *request_count);
88 
89 void blk_account_io_start(struct request *req, bool new_io);
90 void blk_account_io_completion(struct request *req, unsigned int bytes);
91 void blk_account_io_done(struct request *req);
92 
93 /*
94  * Internal atomic flags for request handling
95  */
96 enum rq_atomic_flags {
97 	REQ_ATOM_COMPLETE = 0,
98 	REQ_ATOM_STARTED,
99 };
100 
101 /*
102  * EH timer and IO completion will both attempt to 'grab' the request, make
103  * sure that only one of them succeeds
104  */
blk_mark_rq_complete(struct request * rq)105 static inline int blk_mark_rq_complete(struct request *rq)
106 {
107 	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
108 }
109 
blk_clear_rq_complete(struct request * rq)110 static inline void blk_clear_rq_complete(struct request *rq)
111 {
112 	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
113 }
114 
115 /*
116  * Internal elevator interface
117  */
118 #define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
119 
120 void blk_insert_flush(struct request *rq);
121 
__elv_next_request(struct request_queue * q)122 static inline struct request *__elv_next_request(struct request_queue *q)
123 {
124 	struct request *rq;
125 	struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
126 
127 	while (1) {
128 		if (!list_empty(&q->queue_head)) {
129 			rq = list_entry_rq(q->queue_head.next);
130 			return rq;
131 		}
132 
133 		/*
134 		 * Flush request is running and flush request isn't queueable
135 		 * in the drive, we can hold the queue till flush request is
136 		 * finished. Even we don't do this, driver can't dispatch next
137 		 * requests and will requeue them. And this can improve
138 		 * throughput too. For example, we have request flush1, write1,
139 		 * flush 2. flush1 is dispatched, then queue is hold, write1
140 		 * isn't inserted to queue. After flush1 is finished, flush2
141 		 * will be dispatched. Since disk cache is already clean,
142 		 * flush2 will be finished very soon, so looks like flush2 is
143 		 * folded to flush1.
144 		 * Since the queue is hold, a flag is set to indicate the queue
145 		 * should be restarted later. Please see flush_end_io() for
146 		 * details.
147 		 */
148 		if (fq->flush_pending_idx != fq->flush_running_idx &&
149 				!queue_flush_queueable(q)) {
150 			fq->flush_queue_delayed = 1;
151 			return NULL;
152 		}
153 		if (unlikely(blk_queue_bypass(q)) ||
154 		    !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
155 			return NULL;
156 	}
157 }
158 
elv_activate_rq(struct request_queue * q,struct request * rq)159 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
160 {
161 	struct elevator_queue *e = q->elevator;
162 
163 	if (e->type->ops.elevator_activate_req_fn)
164 		e->type->ops.elevator_activate_req_fn(q, rq);
165 }
166 
elv_deactivate_rq(struct request_queue * q,struct request * rq)167 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
168 {
169 	struct elevator_queue *e = q->elevator;
170 
171 	if (e->type->ops.elevator_deactivate_req_fn)
172 		e->type->ops.elevator_deactivate_req_fn(q, rq);
173 }
174 
175 #ifdef CONFIG_FAIL_IO_TIMEOUT
176 int blk_should_fake_timeout(struct request_queue *);
177 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
178 ssize_t part_timeout_store(struct device *, struct device_attribute *,
179 				const char *, size_t);
180 #else
blk_should_fake_timeout(struct request_queue * q)181 static inline int blk_should_fake_timeout(struct request_queue *q)
182 {
183 	return 0;
184 }
185 #endif
186 
187 int ll_back_merge_fn(struct request_queue *q, struct request *req,
188 		     struct bio *bio);
189 int ll_front_merge_fn(struct request_queue *q, struct request *req,
190 		      struct bio *bio);
191 int attempt_back_merge(struct request_queue *q, struct request *rq);
192 int attempt_front_merge(struct request_queue *q, struct request *rq);
193 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
194 				struct request *next);
195 void blk_recalc_rq_segments(struct request *rq);
196 void blk_rq_set_mixed_merge(struct request *rq);
197 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
198 int blk_try_merge(struct request *rq, struct bio *bio);
199 
200 void blk_queue_congestion_threshold(struct request_queue *q);
201 
202 void __blk_run_queue_uncond(struct request_queue *q);
203 
204 int blk_dev_init(void);
205 
206 
207 /*
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.
211  */
queue_congestion_on_threshold(struct request_queue * q)212 static inline int queue_congestion_on_threshold(struct request_queue *q)
213 {
214 	return q->nr_congestion_on;
215 }
216 
217 /*
218  * The threshold at which a queue is considered to be uncongested
219  */
queue_congestion_off_threshold(struct request_queue * q)220 static inline int queue_congestion_off_threshold(struct request_queue *q)
221 {
222 	return q->nr_congestion_off;
223 }
224 
225 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
226 
227 /*
228  * Contribute to IO statistics IFF:
229  *
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
233  */
blk_do_io_stat(struct request * rq)234 static inline int blk_do_io_stat(struct request *rq)
235 {
236 	return rq->rq_disk &&
237 	       (rq->cmd_flags & REQ_IO_STAT) &&
238 		(rq->cmd_type == REQ_TYPE_FS);
239 }
240 
241 /*
242  * Internal io_context interface
243  */
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,
247 			     gfp_t gfp_mask);
248 void ioc_clear_queue(struct request_queue *q);
249 
250 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
251 
252 /**
253  * create_io_context - try to create task->io_context
254  * @gfp_mask: allocation mask
255  * @node: allocation node
256  *
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
259  * allocation failed.
260  *
261  * Note that this function can't be called with IRQ disabled because
262  * task_lock which protects %current->io_context is IRQ-unsafe.
263  */
create_io_context(gfp_t gfp_mask,int node)264 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
265 {
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;
270 }
271 
272 /*
273  * Internal throttling interface
274  */
275 #ifdef CONFIG_BLK_DEV_THROTTLING
276 extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
277 extern void blk_throtl_drain(struct request_queue *q);
278 extern int blk_throtl_init(struct request_queue *q);
279 extern void blk_throtl_exit(struct request_queue *q);
280 #else /* CONFIG_BLK_DEV_THROTTLING */
blk_throtl_bio(struct request_queue * q,struct bio * bio)281 static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
282 {
283 	return false;
284 }
blk_throtl_drain(struct request_queue * q)285 static inline void blk_throtl_drain(struct request_queue *q) { }
blk_throtl_init(struct request_queue * q)286 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
blk_throtl_exit(struct request_queue * q)287 static inline void blk_throtl_exit(struct request_queue *q) { }
288 #endif /* CONFIG_BLK_DEV_THROTTLING */
289 
290 #endif /* BLK_INTERNAL_H */
291