block/blk-mq.h

   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