xref: /openbmc/linux/block/blk.h (revision d7a3d85e)
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 	spinlock_t		mq_flush_lock;
26 };
27 
28 extern struct kmem_cache *blk_requestq_cachep;
29 extern struct kmem_cache *request_cachep;
30 extern struct kobj_type blk_queue_ktype;
31 extern struct ida blk_queue_ida;
32 
33 static inline struct blk_flush_queue *blk_get_flush_queue(
34 		struct request_queue *q, struct blk_mq_ctx *ctx)
35 {
36 	struct blk_mq_hw_ctx *hctx;
37 
38 	if (!q->mq_ops)
39 		return q->fq;
40 
41 	hctx = q->mq_ops->map_queue(q, ctx->cpu);
42 
43 	return hctx->fq;
44 }
45 
46 static inline void __blk_get_queue(struct request_queue *q)
47 {
48 	kobject_get(&q->kobj);
49 }
50 
51 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
52 		int node, int cmd_size);
53 void blk_free_flush_queue(struct blk_flush_queue *q);
54 
55 int blk_init_rl(struct request_list *rl, struct request_queue *q,
56 		gfp_t gfp_mask);
57 void blk_exit_rl(struct request_list *rl);
58 void init_request_from_bio(struct request *req, struct bio *bio);
59 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
60 			struct bio *bio);
61 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
62 		      struct bio *bio);
63 void blk_queue_bypass_start(struct request_queue *q);
64 void blk_queue_bypass_end(struct request_queue *q);
65 void blk_dequeue_request(struct request *rq);
66 void __blk_queue_free_tags(struct request_queue *q);
67 bool __blk_end_bidi_request(struct request *rq, int error,
68 			    unsigned int nr_bytes, unsigned int bidi_bytes);
69 
70 void blk_rq_timed_out_timer(unsigned long data);
71 unsigned long blk_rq_timeout(unsigned long timeout);
72 void blk_add_timer(struct request *req);
73 void blk_delete_timer(struct request *);
74 
75 
76 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
77 			     struct bio *bio);
78 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
79 			    struct bio *bio);
80 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
81 			    unsigned int *request_count);
82 
83 void blk_account_io_start(struct request *req, bool new_io);
84 void blk_account_io_completion(struct request *req, unsigned int bytes);
85 void blk_account_io_done(struct request *req);
86 
87 /*
88  * Internal atomic flags for request handling
89  */
90 enum rq_atomic_flags {
91 	REQ_ATOM_COMPLETE = 0,
92 	REQ_ATOM_STARTED,
93 };
94 
95 /*
96  * EH timer and IO completion will both attempt to 'grab' the request, make
97  * sure that only one of them succeeds
98  */
99 static inline int blk_mark_rq_complete(struct request *rq)
100 {
101 	return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
102 }
103 
104 static inline void blk_clear_rq_complete(struct request *rq)
105 {
106 	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
107 }
108 
109 /*
110  * Internal elevator interface
111  */
112 #define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
113 
114 void blk_insert_flush(struct request *rq);
115 
116 static inline struct request *__elv_next_request(struct request_queue *q)
117 {
118 	struct request *rq;
119 	struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
120 
121 	while (1) {
122 		if (!list_empty(&q->queue_head)) {
123 			rq = list_entry_rq(q->queue_head.next);
124 			return rq;
125 		}
126 
127 		/*
128 		 * Flush request is running and flush request isn't queueable
129 		 * in the drive, we can hold the queue till flush request is
130 		 * finished. Even we don't do this, driver can't dispatch next
131 		 * requests and will requeue them. And this can improve
132 		 * throughput too. For example, we have request flush1, write1,
133 		 * flush 2. flush1 is dispatched, then queue is hold, write1
134 		 * isn't inserted to queue. After flush1 is finished, flush2
135 		 * will be dispatched. Since disk cache is already clean,
136 		 * flush2 will be finished very soon, so looks like flush2 is
137 		 * folded to flush1.
138 		 * Since the queue is hold, a flag is set to indicate the queue
139 		 * should be restarted later. Please see flush_end_io() for
140 		 * details.
141 		 */
142 		if (fq->flush_pending_idx != fq->flush_running_idx &&
143 				!queue_flush_queueable(q)) {
144 			fq->flush_queue_delayed = 1;
145 			return NULL;
146 		}
147 		if (unlikely(blk_queue_bypass(q)) ||
148 		    !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
149 			return NULL;
150 	}
151 }
152 
153 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
154 {
155 	struct elevator_queue *e = q->elevator;
156 
157 	if (e->type->ops.elevator_activate_req_fn)
158 		e->type->ops.elevator_activate_req_fn(q, rq);
159 }
160 
161 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
162 {
163 	struct elevator_queue *e = q->elevator;
164 
165 	if (e->type->ops.elevator_deactivate_req_fn)
166 		e->type->ops.elevator_deactivate_req_fn(q, rq);
167 }
168 
169 #ifdef CONFIG_FAIL_IO_TIMEOUT
170 int blk_should_fake_timeout(struct request_queue *);
171 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
172 ssize_t part_timeout_store(struct device *, struct device_attribute *,
173 				const char *, size_t);
174 #else
175 static inline int blk_should_fake_timeout(struct request_queue *q)
176 {
177 	return 0;
178 }
179 #endif
180 
181 int ll_back_merge_fn(struct request_queue *q, struct request *req,
182 		     struct bio *bio);
183 int ll_front_merge_fn(struct request_queue *q, struct request *req,
184 		      struct bio *bio);
185 int attempt_back_merge(struct request_queue *q, struct request *rq);
186 int attempt_front_merge(struct request_queue *q, struct request *rq);
187 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
188 				struct request *next);
189 void blk_recalc_rq_segments(struct request *rq);
190 void blk_rq_set_mixed_merge(struct request *rq);
191 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
192 int blk_try_merge(struct request *rq, struct bio *bio);
193 
194 void blk_queue_congestion_threshold(struct request_queue *q);
195 
196 void __blk_run_queue_uncond(struct request_queue *q);
197 
198 int blk_dev_init(void);
199 
200 
201 /*
202  * Return the threshold (number of used requests) at which the queue is
203  * considered to be congested.  It include a little hysteresis to keep the
204  * context switch rate down.
205  */
206 static inline int queue_congestion_on_threshold(struct request_queue *q)
207 {
208 	return q->nr_congestion_on;
209 }
210 
211 /*
212  * The threshold at which a queue is considered to be uncongested
213  */
214 static inline int queue_congestion_off_threshold(struct request_queue *q)
215 {
216 	return q->nr_congestion_off;
217 }
218 
219 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
220 
221 /*
222  * Contribute to IO statistics IFF:
223  *
224  *	a) it's attached to a gendisk, and
225  *	b) the queue had IO stats enabled when this request was started, and
226  *	c) it's a file system request
227  */
228 static inline int blk_do_io_stat(struct request *rq)
229 {
230 	return rq->rq_disk &&
231 	       (rq->cmd_flags & REQ_IO_STAT) &&
232 		(rq->cmd_type == REQ_TYPE_FS);
233 }
234 
235 /*
236  * Internal io_context interface
237  */
238 void get_io_context(struct io_context *ioc);
239 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
240 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
241 			     gfp_t gfp_mask);
242 void ioc_clear_queue(struct request_queue *q);
243 
244 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
245 
246 /**
247  * create_io_context - try to create task->io_context
248  * @gfp_mask: allocation mask
249  * @node: allocation node
250  *
251  * If %current->io_context is %NULL, allocate a new io_context and install
252  * it.  Returns the current %current->io_context which may be %NULL if
253  * allocation failed.
254  *
255  * Note that this function can't be called with IRQ disabled because
256  * task_lock which protects %current->io_context is IRQ-unsafe.
257  */
258 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
259 {
260 	WARN_ON_ONCE(irqs_disabled());
261 	if (unlikely(!current->io_context))
262 		create_task_io_context(current, gfp_mask, node);
263 	return current->io_context;
264 }
265 
266 /*
267  * Internal throttling interface
268  */
269 #ifdef CONFIG_BLK_DEV_THROTTLING
270 extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
271 extern void blk_throtl_drain(struct request_queue *q);
272 extern int blk_throtl_init(struct request_queue *q);
273 extern void blk_throtl_exit(struct request_queue *q);
274 #else /* CONFIG_BLK_DEV_THROTTLING */
275 static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
276 {
277 	return false;
278 }
279 static inline void blk_throtl_drain(struct request_queue *q) { }
280 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
281 static inline void blk_throtl_exit(struct request_queue *q) { }
282 #endif /* CONFIG_BLK_DEV_THROTTLING */
283 
284 #endif /* BLK_INTERNAL_H */
285