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