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 request_queue *, struct list_head *, bool);
  44 void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
  45                                 bool kick_requeue_list);
  46 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list);
  47 bool blk_mq_get_driver_tag(struct request *rq);
  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);
  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 int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
  62                      unsigned int hctx_idx, unsigned int depth);
  63
  64 /*
  65  * Internal helpers for request insertion into sw queues
  66  */
  67 void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
  68                                 bool at_head);
  69 void blk_mq_request_bypass_insert(struct request *rq, bool run_queue);
  70 void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
  71                                 struct list_head *list);
  72
  73 /* Used by blk_insert_cloned_request() to issue request directly */
  74 blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last);
  75 void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
  76                                     struct list_head *list);
  77
  78 /*
  79  * CPU -> queue mappings
  80  */
  81 extern int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int);
  82
  83 /*
  84  * blk_mq_map_queue_type() - map (hctx_type,cpu) to hardware queue
  85  * @q: request queue
  86  * @type: the hctx type index
  87  * @cpu: CPU
  88  */
  89 static inline struct blk_mq_hw_ctx *blk_mq_map_queue_type(struct request_queue *q,
  90                                                           enum hctx_type type,
  91                                                           unsigned int cpu)
  92 {
  93         return q->queue_hw_ctx[q->tag_set->map[type].mq_map[cpu]];
  94 }
  95
  96 /*
  97  * blk_mq_map_queue() - map (cmd_flags,type) to hardware queue
  98  * @q: request queue
  99  * @flags: request command flags
 100  * @cpu: cpu ctx
 101  */
 102 static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
 103                                                      unsigned int flags,
 104                                                      struct blk_mq_ctx *ctx)
 105 {
 106         enum hctx_type type = HCTX_TYPE_DEFAULT;
 107
 108         /*
 109          * The caller ensure that if REQ_HIPRI, poll must be enabled.
 110          */
 111         if (flags & REQ_HIPRI)
 112                 type = HCTX_TYPE_POLL;
 113         else if ((flags & REQ_OP_MASK) == REQ_OP_READ)
 114                 type = HCTX_TYPE_READ;
 115
 116         return ctx->hctxs[type];
 117 }
 118
 119 /*
 120  * sysfs helpers
 121  */
 122 extern void blk_mq_sysfs_init(struct request_queue *q);
 123 extern void blk_mq_sysfs_deinit(struct request_queue *q);
 124 extern int __blk_mq_register_dev(struct device *dev, struct request_queue *q);
 125 extern int blk_mq_sysfs_register(struct request_queue *q);
 126 extern void blk_mq_sysfs_unregister(struct request_queue *q);
 127 extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);
 128
 129 void blk_mq_release(struct request_queue *q);
 130
 131 /**
 132  * blk_mq_rq_state() - read the current MQ_RQ_* state of a request
 133  * @rq: target request.
 134  */
 135 static inline enum mq_rq_state blk_mq_rq_state(struct request *rq)
 136 {
 137         return READ_ONCE(rq->state);
 138 }
 139
 140 static inline struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q,
 141                                            unsigned int cpu)
 142 {
 143         return per_cpu_ptr(q->queue_ctx, cpu);
 144 }
 145
 146 /*
 147  * This assumes per-cpu software queueing queues. They could be per-node
 148  * as well, for instance. For now this is hardcoded as-is. Note that we don't
 149  * care about preemption, since we know the ctx's are persistent. This does
 150  * mean that we can't rely on ctx always matching the currently running CPU.
 151  */
 152 static inline struct blk_mq_ctx *blk_mq_get_ctx(struct request_queue *q)
 153 {
 154         return __blk_mq_get_ctx(q, raw_smp_processor_id());
 155 }
 156
 157 struct blk_mq_alloc_data {
 158         /* input parameter */
 159         struct request_queue *q;
 160         blk_mq_req_flags_t flags;
 161         unsigned int shallow_depth;
 162         unsigned int cmd_flags;
 163
 164         /* input & output parameter */
 165         struct blk_mq_ctx *ctx;
 166         struct blk_mq_hw_ctx *hctx;
 167 };
 168
 169 static inline struct blk_mq_tags *blk_mq_tags_from_data(struct blk_mq_alloc_data *data)
 170 {
 171         if (data->flags & BLK_MQ_REQ_INTERNAL)
 172                 return data->hctx->sched_tags;
 173
 174         return data->hctx->tags;
 175 }
 176
 177 static inline bool blk_mq_hctx_stopped(struct blk_mq_hw_ctx *hctx)
 178 {
 179         return test_bit(BLK_MQ_S_STOPPED, &hctx->state);
 180 }
 181
 182 static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
 183 {
 184         return hctx->nr_ctx && hctx->tags;
 185 }
 186
 187 unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part);
 188 void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part,
 189                          unsigned int inflight[2]);
 190
 191 static inline void blk_mq_put_dispatch_budget(struct blk_mq_hw_ctx *hctx)
 192 {
 193         struct request_queue *q = hctx->queue;
 194
 195         if (q->mq_ops->put_budget)
 196                 q->mq_ops->put_budget(hctx);
 197 }
 198
 199 static inline bool blk_mq_get_dispatch_budget(struct blk_mq_hw_ctx *hctx)
 200 {
 201         struct request_queue *q = hctx->queue;
 202
 203         if (q->mq_ops->get_budget)
 204                 return q->mq_ops->get_budget(hctx);
 205         return true;
 206 }
 207
 208 static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
 209                                            struct request *rq)
 210 {
 211         blk_mq_put_tag(hctx, hctx->tags, rq->mq_ctx, rq->tag);
 212         rq->tag = -1;
 213
 214         if (rq->rq_flags & RQF_MQ_INFLIGHT) {
 215                 rq->rq_flags &= ~RQF_MQ_INFLIGHT;
 216                 atomic_dec(&hctx->nr_active);
 217         }
 218 }
 219
 220 static inline void blk_mq_put_driver_tag(struct request *rq)
 221 {
 222         if (rq->tag == -1 || rq->internal_tag == -1)
 223                 return;
 224
 225         __blk_mq_put_driver_tag(rq->mq_hctx, rq);
 226 }
 227
 228 static inline void blk_mq_clear_mq_map(struct blk_mq_queue_map *qmap)
 229 {
 230         int cpu;
 231
 232         for_each_possible_cpu(cpu)
 233                 qmap->mq_map[cpu] = 0;
 234 }
 235
 236 /*
 237  * blk_mq_plug() - Get caller context plug
 238  * @q: request queue
 239  * @bio : the bio being submitted by the caller context
 240  *
 241  * Plugging, by design, may delay the insertion of BIOs into the elevator in
 242  * order to increase BIO merging opportunities. This however can cause BIO
 243  * insertion order to change from the order in which submit_bio() is being
 244  * executed in the case of multiple contexts concurrently issuing BIOs to a
 245  * device, even if these context are synchronized to tightly control BIO issuing
 246  * order. While this is not a problem with regular block devices, this ordering
 247  * change can cause write BIO failures with zoned block devices as these
 248  * require sequential write patterns to zones. Prevent this from happening by
 249  * ignoring the plug state of a BIO issuing context if the target request queue
 250  * is for a zoned block device and the BIO to plug is a write operation.
 251  *
 252  * Return current->plug if the bio can be plugged and NULL otherwise
 253  */
 254 static inline struct blk_plug *blk_mq_plug(struct request_queue *q,
 255                                            struct bio *bio)
 256 {
 257         /*
 258          * For regular block devices or read operations, use the context plug
 259          * which may be NULL if blk_start_plug() was not executed.
 260          */
 261         if (!blk_queue_is_zoned(q) || !op_is_write(bio_op(bio)))
 262                 return current->plug;
 263
 264         /* Zoned block device write operation case: do not plug the BIO */
 265         return NULL;
 266 }
 267
 268 #endif