xref: /linux/block/blk-mq.h (revision 3f374d7972c48bc0824bdabb8f94fe82e54fd07d)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef INT_BLK_MQ_H
3 #define INT_BLK_MQ_H
4 
5 #include "blk-stat.h"
6 #include "blk-mq-tag.h"
7 
8 struct blk_mq_tag_set;
9 
10 struct blk_mq_ctxs {
11 	struct kobject kobj;
12 	struct blk_mq_ctx __percpu	*queue_ctx;
13 };
14 
15 /**
16  * struct blk_mq_ctx - State for a software queue facing the submitting CPUs
17  */
18 struct blk_mq_ctx {
19 	struct {
20 		spinlock_t		lock;
21 		struct list_head	rq_lists[HCTX_MAX_TYPES];
22 	} ____cacheline_aligned_in_smp;
23 
24 	unsigned int		cpu;
25 	unsigned short		index_hw[HCTX_MAX_TYPES];
26 	struct blk_mq_hw_ctx 	*hctxs[HCTX_MAX_TYPES];
27 
28 	struct request_queue	*queue;
29 	struct blk_mq_ctxs      *ctxs;
30 	struct kobject		kobj;
31 } ____cacheline_aligned_in_smp;
32 
33 void blk_mq_submit_bio(struct bio *bio);
34 int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, struct io_comp_batch *iob,
35 		unsigned int flags);
36 void blk_mq_exit_queue(struct request_queue *q);
37 int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr);
38 void blk_mq_wake_waiters(struct request_queue *q);
39 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *,
40 			     unsigned int);
41 void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
42 				bool kick_requeue_list);
43 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list);
44 struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
45 					struct blk_mq_ctx *start);
46 void blk_mq_put_rq_ref(struct request *rq);
47 
48 /*
49  * Internal helpers for allocating/freeing the request map
50  */
51 void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
52 		     unsigned int hctx_idx);
53 void blk_mq_free_rq_map(struct blk_mq_tags *tags);
54 struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
55 				unsigned int hctx_idx, unsigned int depth);
56 void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
57 			     struct blk_mq_tags *tags,
58 			     unsigned int hctx_idx);
59 /*
60  * Internal helpers for request insertion into sw queues
61  */
62 void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
63 				bool at_head);
64 void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
65 				  bool run_queue);
66 void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
67 				struct list_head *list);
68 void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
69 				    struct list_head *list);
70 
71 /*
72  * CPU -> queue mappings
73  */
74 extern int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int);
75 
76 /*
77  * blk_mq_map_queue_type() - map (hctx_type,cpu) to hardware queue
78  * @q: request queue
79  * @type: the hctx type index
80  * @cpu: CPU
81  */
82 static inline struct blk_mq_hw_ctx *blk_mq_map_queue_type(struct request_queue *q,
83 							  enum hctx_type type,
84 							  unsigned int cpu)
85 {
86 	return xa_load(&q->hctx_table, q->tag_set->map[type].mq_map[cpu]);
87 }
88 
89 static inline enum hctx_type blk_mq_get_hctx_type(unsigned int flags)
90 {
91 	enum hctx_type type = HCTX_TYPE_DEFAULT;
92 
93 	/*
94 	 * The caller ensure that if REQ_POLLED, poll must be enabled.
95 	 */
96 	if (flags & REQ_POLLED)
97 		type = HCTX_TYPE_POLL;
98 	else if ((flags & REQ_OP_MASK) == REQ_OP_READ)
99 		type = HCTX_TYPE_READ;
100 	return type;
101 }
102 
103 /*
104  * blk_mq_map_queue() - map (cmd_flags,type) to hardware queue
105  * @q: request queue
106  * @flags: request command flags
107  * @ctx: software queue cpu ctx
108  */
109 static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
110 						     unsigned int flags,
111 						     struct blk_mq_ctx *ctx)
112 {
113 	return ctx->hctxs[blk_mq_get_hctx_type(flags)];
114 }
115 
116 /*
117  * sysfs helpers
118  */
119 extern void blk_mq_sysfs_init(struct request_queue *q);
120 extern void blk_mq_sysfs_deinit(struct request_queue *q);
121 extern int __blk_mq_register_dev(struct device *dev, struct request_queue *q);
122 extern int blk_mq_sysfs_register(struct request_queue *q);
123 extern void blk_mq_sysfs_unregister(struct request_queue *q);
124 extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);
125 void blk_mq_free_plug_rqs(struct blk_plug *plug);
126 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
127 
128 void blk_mq_cancel_work_sync(struct request_queue *q);
129 
130 void blk_mq_release(struct request_queue *q);
131 
132 static inline struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q,
133 					   unsigned int cpu)
134 {
135 	return per_cpu_ptr(q->queue_ctx, cpu);
136 }
137 
138 /*
139  * This assumes per-cpu software queueing queues. They could be per-node
140  * as well, for instance. For now this is hardcoded as-is. Note that we don't
141  * care about preemption, since we know the ctx's are persistent. This does
142  * mean that we can't rely on ctx always matching the currently running CPU.
143  */
144 static inline struct blk_mq_ctx *blk_mq_get_ctx(struct request_queue *q)
145 {
146 	return __blk_mq_get_ctx(q, raw_smp_processor_id());
147 }
148 
149 struct blk_mq_alloc_data {
150 	/* input parameter */
151 	struct request_queue *q;
152 	blk_mq_req_flags_t flags;
153 	unsigned int shallow_depth;
154 	unsigned int cmd_flags;
155 	req_flags_t rq_flags;
156 
157 	/* allocate multiple requests/tags in one go */
158 	unsigned int nr_tags;
159 	struct request **cached_rq;
160 
161 	/* input & output parameter */
162 	struct blk_mq_ctx *ctx;
163 	struct blk_mq_hw_ctx *hctx;
164 };
165 
166 static inline bool blk_mq_is_shared_tags(unsigned int flags)
167 {
168 	return flags & BLK_MQ_F_TAG_HCTX_SHARED;
169 }
170 
171 static inline struct blk_mq_tags *blk_mq_tags_from_data(struct blk_mq_alloc_data *data)
172 {
173 	if (!(data->rq_flags & RQF_ELV))
174 		return data->hctx->tags;
175 	return data->hctx->sched_tags;
176 }
177 
178 static inline bool blk_mq_hctx_stopped(struct blk_mq_hw_ctx *hctx)
179 {
180 	return test_bit(BLK_MQ_S_STOPPED, &hctx->state);
181 }
182 
183 static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
184 {
185 	return hctx->nr_ctx && hctx->tags;
186 }
187 
188 unsigned int blk_mq_in_flight(struct request_queue *q,
189 		struct block_device *part);
190 void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
191 		unsigned int inflight[2]);
192 
193 static inline void blk_mq_put_dispatch_budget(struct request_queue *q,
194 					      int budget_token)
195 {
196 	if (q->mq_ops->put_budget)
197 		q->mq_ops->put_budget(q, budget_token);
198 }
199 
200 static inline int blk_mq_get_dispatch_budget(struct request_queue *q)
201 {
202 	if (q->mq_ops->get_budget)
203 		return q->mq_ops->get_budget(q);
204 	return 0;
205 }
206 
207 static inline void blk_mq_set_rq_budget_token(struct request *rq, int token)
208 {
209 	if (token < 0)
210 		return;
211 
212 	if (rq->q->mq_ops->set_rq_budget_token)
213 		rq->q->mq_ops->set_rq_budget_token(rq, token);
214 }
215 
216 static inline int blk_mq_get_rq_budget_token(struct request *rq)
217 {
218 	if (rq->q->mq_ops->get_rq_budget_token)
219 		return rq->q->mq_ops->get_rq_budget_token(rq);
220 	return -1;
221 }
222 
223 static inline void __blk_mq_inc_active_requests(struct blk_mq_hw_ctx *hctx)
224 {
225 	if (blk_mq_is_shared_tags(hctx->flags))
226 		atomic_inc(&hctx->queue->nr_active_requests_shared_tags);
227 	else
228 		atomic_inc(&hctx->nr_active);
229 }
230 
231 static inline void __blk_mq_sub_active_requests(struct blk_mq_hw_ctx *hctx,
232 		int val)
233 {
234 	if (blk_mq_is_shared_tags(hctx->flags))
235 		atomic_sub(val, &hctx->queue->nr_active_requests_shared_tags);
236 	else
237 		atomic_sub(val, &hctx->nr_active);
238 }
239 
240 static inline void __blk_mq_dec_active_requests(struct blk_mq_hw_ctx *hctx)
241 {
242 	__blk_mq_sub_active_requests(hctx, 1);
243 }
244 
245 static inline int __blk_mq_active_requests(struct blk_mq_hw_ctx *hctx)
246 {
247 	if (blk_mq_is_shared_tags(hctx->flags))
248 		return atomic_read(&hctx->queue->nr_active_requests_shared_tags);
249 	return atomic_read(&hctx->nr_active);
250 }
251 static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
252 					   struct request *rq)
253 {
254 	blk_mq_put_tag(hctx->tags, rq->mq_ctx, rq->tag);
255 	rq->tag = BLK_MQ_NO_TAG;
256 
257 	if (rq->rq_flags & RQF_MQ_INFLIGHT) {
258 		rq->rq_flags &= ~RQF_MQ_INFLIGHT;
259 		__blk_mq_dec_active_requests(hctx);
260 	}
261 }
262 
263 static inline void blk_mq_put_driver_tag(struct request *rq)
264 {
265 	if (rq->tag == BLK_MQ_NO_TAG || rq->internal_tag == BLK_MQ_NO_TAG)
266 		return;
267 
268 	__blk_mq_put_driver_tag(rq->mq_hctx, rq);
269 }
270 
271 bool __blk_mq_get_driver_tag(struct blk_mq_hw_ctx *hctx, struct request *rq);
272 
273 static inline bool blk_mq_get_driver_tag(struct request *rq)
274 {
275 	struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
276 
277 	if (rq->tag != BLK_MQ_NO_TAG &&
278 	    !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
279 		hctx->tags->rqs[rq->tag] = rq;
280 		return true;
281 	}
282 
283 	return __blk_mq_get_driver_tag(hctx, rq);
284 }
285 
286 static inline void blk_mq_clear_mq_map(struct blk_mq_queue_map *qmap)
287 {
288 	int cpu;
289 
290 	for_each_possible_cpu(cpu)
291 		qmap->mq_map[cpu] = 0;
292 }
293 
294 /*
295  * blk_mq_plug() - Get caller context plug
296  * @q: request queue
297  * @bio : the bio being submitted by the caller context
298  *
299  * Plugging, by design, may delay the insertion of BIOs into the elevator in
300  * order to increase BIO merging opportunities. This however can cause BIO
301  * insertion order to change from the order in which submit_bio() is being
302  * executed in the case of multiple contexts concurrently issuing BIOs to a
303  * device, even if these context are synchronized to tightly control BIO issuing
304  * order. While this is not a problem with regular block devices, this ordering
305  * change can cause write BIO failures with zoned block devices as these
306  * require sequential write patterns to zones. Prevent this from happening by
307  * ignoring the plug state of a BIO issuing context if the target request queue
308  * is for a zoned block device and the BIO to plug is a write operation.
309  *
310  * Return current->plug if the bio can be plugged and NULL otherwise
311  */
312 static inline struct blk_plug *blk_mq_plug(struct request_queue *q,
313 					   struct bio *bio)
314 {
315 	/*
316 	 * For regular block devices or read operations, use the context plug
317 	 * which may be NULL if blk_start_plug() was not executed.
318 	 */
319 	if (!blk_queue_is_zoned(q) || !op_is_write(bio_op(bio)))
320 		return current->plug;
321 
322 	/* Zoned block device write operation case: do not plug the BIO */
323 	return NULL;
324 }
325 
326 /* Free all requests on the list */
327 static inline void blk_mq_free_requests(struct list_head *list)
328 {
329 	while (!list_empty(list)) {
330 		struct request *rq = list_entry_rq(list->next);
331 
332 		list_del_init(&rq->queuelist);
333 		blk_mq_free_request(rq);
334 	}
335 }
336 
337 /*
338  * For shared tag users, we track the number of currently active users
339  * and attempt to provide a fair share of the tag depth for each of them.
340  */
341 static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
342 				  struct sbitmap_queue *bt)
343 {
344 	unsigned int depth, users;
345 
346 	if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED))
347 		return true;
348 
349 	/*
350 	 * Don't try dividing an ant
351 	 */
352 	if (bt->sb.depth == 1)
353 		return true;
354 
355 	if (blk_mq_is_shared_tags(hctx->flags)) {
356 		struct request_queue *q = hctx->queue;
357 
358 		if (!test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags))
359 			return true;
360 	} else {
361 		if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
362 			return true;
363 	}
364 
365 	users = atomic_read(&hctx->tags->active_queues);
366 
367 	if (!users)
368 		return true;
369 
370 	/*
371 	 * Allow at least some tags
372 	 */
373 	depth = max((bt->sb.depth + users - 1) / users, 4U);
374 	return __blk_mq_active_requests(hctx) < depth;
375 }
376 
377 /* run the code block in @dispatch_ops with rcu/srcu read lock held */
378 #define __blk_mq_run_dispatch_ops(q, check_sleep, dispatch_ops)	\
379 do {								\
380 	if (!blk_queue_has_srcu(q)) {				\
381 		rcu_read_lock();				\
382 		(dispatch_ops);					\
383 		rcu_read_unlock();				\
384 	} else {						\
385 		int srcu_idx;					\
386 								\
387 		might_sleep_if(check_sleep);			\
388 		srcu_idx = srcu_read_lock((q)->srcu);		\
389 		(dispatch_ops);					\
390 		srcu_read_unlock((q)->srcu, srcu_idx);		\
391 	}							\
392 } while (0)
393 
394 #define blk_mq_run_dispatch_ops(q, dispatch_ops)		\
395 	__blk_mq_run_dispatch_ops(q, true, dispatch_ops)	\
396 
397 #endif
398