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