include/linux/blk-mq.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef BLK_MQ_H
   3 #define BLK_MQ_H
   4
   5 #include <linux/blkdev.h>
   6 #include <linux/sbitmap.h>
   7 #include <linux/srcu.h>
   8
   9 struct blk_mq_tags;
  10 struct blk_flush_queue;
  11
  12 /**
  13  * struct blk_mq_hw_ctx - State for a hardware queue facing the hardware block device
  14  */
  15 struct blk_mq_hw_ctx {
  16         struct {
  17                 spinlock_t              lock;
  18                 struct list_head        dispatch;
  19                 unsigned long           state;          /* BLK_MQ_S_* flags */
  20         } ____cacheline_aligned_in_smp;
  21
  22         struct delayed_work     run_work;
  23         cpumask_var_t           cpumask;
  24         int                     next_cpu;
  25         int                     next_cpu_batch;
  26
  27         unsigned long           flags;          /* BLK_MQ_F_* flags */
  28
  29         void                    *sched_data;
  30         struct request_queue    *queue;
  31         struct blk_flush_queue  *fq;
  32
  33         void                    *driver_data;
  34
  35         struct sbitmap          ctx_map;
  36
  37         struct blk_mq_ctx       *dispatch_from;
  38         unsigned int            dispatch_busy;
  39
  40         unsigned short          type;
  41         unsigned short          nr_ctx;
  42         struct blk_mq_ctx       **ctxs;
  43
  44         spinlock_t              dispatch_wait_lock;
  45         wait_queue_entry_t      dispatch_wait;
  46         atomic_t                wait_index;
  47
  48         struct blk_mq_tags      *tags;
  49         struct blk_mq_tags      *sched_tags;
  50
  51         unsigned long           queued;
  52         unsigned long           run;
  53 #define BLK_MQ_MAX_DISPATCH_ORDER       7
  54         unsigned long           dispatched[BLK_MQ_MAX_DISPATCH_ORDER];
  55
  56         unsigned int            numa_node;
  57         unsigned int            queue_num;
  58
  59         atomic_t                nr_active;
  60
  61         struct hlist_node       cpuhp_dead;
  62         struct kobject          kobj;
  63
  64         unsigned long           poll_considered;
  65         unsigned long           poll_invoked;
  66         unsigned long           poll_success;
  67
  68 #ifdef CONFIG_BLK_DEBUG_FS
  69         struct dentry           *debugfs_dir;
  70         struct dentry           *sched_debugfs_dir;
  71 #endif
  72
  73         /* Must be the last member - see also blk_mq_hw_ctx_size(). */
  74         struct srcu_struct      srcu[0];
  75 };
  76
  77 struct blk_mq_queue_map {
  78         unsigned int *mq_map;
  79         unsigned int nr_queues;
  80         unsigned int queue_offset;
  81 };
  82
  83 enum hctx_type {
  84         HCTX_TYPE_DEFAULT,      /* all I/O not otherwise accounted for */
  85         HCTX_TYPE_READ,         /* just for READ I/O */
  86         HCTX_TYPE_POLL,         /* polled I/O of any kind */
  87
  88         HCTX_MAX_TYPES,
  89 };
  90
  91 struct blk_mq_tag_set {
  92         /*
  93          * map[] holds ctx -> hctx mappings, one map exists for each type
  94          * that the driver wishes to support. There are no restrictions
  95          * on maps being of the same size, and it's perfectly legal to
  96          * share maps between types.
  97          */
  98         struct blk_mq_queue_map map[HCTX_MAX_TYPES];
  99         unsigned int            nr_maps;        /* nr entries in map[] */
 100         const struct blk_mq_ops *ops;
 101         unsigned int            nr_hw_queues;   /* nr hw queues across maps */
 102         unsigned int            queue_depth;    /* max hw supported */
 103         unsigned int            reserved_tags;
 104         unsigned int            cmd_size;       /* per-request extra data */
 105         int                     numa_node;
 106         unsigned int            timeout;
 107         unsigned int            flags;          /* BLK_MQ_F_* */
 108         void                    *driver_data;
 109
 110         struct blk_mq_tags      **tags;
 111
 112         struct mutex            tag_list_lock;
 113         struct list_head        tag_list;
 114 };
 115
 116 struct blk_mq_queue_data {
 117         struct request *rq;
 118         bool last;
 119 };
 120
 121 typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *,
 122                 const struct blk_mq_queue_data *);
 123 typedef void (commit_rqs_fn)(struct blk_mq_hw_ctx *);
 124 typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *);
 125 typedef void (put_budget_fn)(struct blk_mq_hw_ctx *);
 126 typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
 127 typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
 128 typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
 129 typedef int (init_request_fn)(struct blk_mq_tag_set *set, struct request *,
 130                 unsigned int, unsigned int);
 131 typedef void (exit_request_fn)(struct blk_mq_tag_set *set, struct request *,
 132                 unsigned int);
 133
 134 typedef bool (busy_iter_fn)(struct blk_mq_hw_ctx *, struct request *, void *,
 135                 bool);
 136 typedef bool (busy_tag_iter_fn)(struct request *, void *, bool);
 137 typedef int (poll_fn)(struct blk_mq_hw_ctx *);
 138 typedef int (map_queues_fn)(struct blk_mq_tag_set *set);
 139 typedef bool (busy_fn)(struct request_queue *);
 140 typedef void (complete_fn)(struct request *);
 141
 142
 143 struct blk_mq_ops {
 144         /*
 145          * Queue request
 146          */
 147         queue_rq_fn             *queue_rq;
 148
 149         /*
 150          * If a driver uses bd->last to judge when to submit requests to
 151          * hardware, it must define this function. In case of errors that
 152          * make us stop issuing further requests, this hook serves the
 153          * purpose of kicking the hardware (which the last request otherwise
 154          * would have done).
 155          */
 156         commit_rqs_fn           *commit_rqs;
 157
 158         /*
 159          * Reserve budget before queue request, once .queue_rq is
 160          * run, it is driver's responsibility to release the
 161          * reserved budget. Also we have to handle failure case
 162          * of .get_budget for avoiding I/O deadlock.
 163          */
 164         get_budget_fn           *get_budget;
 165         put_budget_fn           *put_budget;
 166
 167         /*
 168          * Called on request timeout
 169          */
 170         timeout_fn              *timeout;
 171
 172         /*
 173          * Called to poll for completion of a specific tag.
 174          */
 175         poll_fn                 *poll;
 176
 177         complete_fn             *complete;
 178
 179         /*
 180          * Called when the block layer side of a hardware queue has been
 181          * set up, allowing the driver to allocate/init matching structures.
 182          * Ditto for exit/teardown.
 183          */
 184         init_hctx_fn            *init_hctx;
 185         exit_hctx_fn            *exit_hctx;
 186
 187         /*
 188          * Called for every command allocated by the block layer to allow
 189          * the driver to set up driver specific data.
 190          *
 191          * Tag greater than or equal to queue_depth is for setting up
 192          * flush request.
 193          *
 194          * Ditto for exit/teardown.
 195          */
 196         init_request_fn         *init_request;
 197         exit_request_fn         *exit_request;
 198         /* Called from inside blk_get_request() */
 199         void (*initialize_rq_fn)(struct request *rq);
 200
 201         /*
 202          * If set, returns whether or not this queue currently is busy
 203          */
 204         busy_fn                 *busy;
 205
 206         map_queues_fn           *map_queues;
 207
 208 #ifdef CONFIG_BLK_DEBUG_FS
 209         /*
 210          * Used by the debugfs implementation to show driver-specific
 211          * information about a request.
 212          */
 213         void (*show_rq)(struct seq_file *m, struct request *rq);
 214 #endif
 215 };
 216
 217 enum {
 218         BLK_MQ_F_SHOULD_MERGE   = 1 << 0,
 219         BLK_MQ_F_TAG_SHARED     = 1 << 1,
 220         BLK_MQ_F_BLOCKING       = 1 << 5,
 221         BLK_MQ_F_NO_SCHED       = 1 << 6,
 222         BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
 223         BLK_MQ_F_ALLOC_POLICY_BITS = 1,
 224
 225         BLK_MQ_S_STOPPED        = 0,
 226         BLK_MQ_S_TAG_ACTIVE     = 1,
 227         BLK_MQ_S_SCHED_RESTART  = 2,
 228
 229         BLK_MQ_MAX_DEPTH        = 10240,
 230
 231         BLK_MQ_CPU_WORK_BATCH   = 8,
 232 };
 233 #define BLK_MQ_FLAG_TO_ALLOC_POLICY(flags) \
 234         ((flags >> BLK_MQ_F_ALLOC_POLICY_START_BIT) & \
 235                 ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1))
 236 #define BLK_ALLOC_POLICY_TO_MQ_FLAG(policy) \
 237         ((policy & ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1)) \
 238                 << BLK_MQ_F_ALLOC_POLICY_START_BIT)
 239
 240 struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *);
 241 struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
 242                                                   struct request_queue *q);
 243 struct request_queue *blk_mq_init_sq_queue(struct blk_mq_tag_set *set,
 244                                                 const struct blk_mq_ops *ops,
 245                                                 unsigned int queue_depth,
 246                                                 unsigned int set_flags);
 247 int blk_mq_register_dev(struct device *, struct request_queue *);
 248 void blk_mq_unregister_dev(struct device *, struct request_queue *);
 249
 250 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set);
 251 void blk_mq_free_tag_set(struct blk_mq_tag_set *set);
 252
 253 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
 254
 255 void blk_mq_free_request(struct request *rq);
 256 bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
 257
 258 bool blk_mq_queue_inflight(struct request_queue *q);
 259
 260 enum {
 261         /* return when out of requests */
 262         BLK_MQ_REQ_NOWAIT       = (__force blk_mq_req_flags_t)(1 << 0),
 263         /* allocate from reserved pool */
 264         BLK_MQ_REQ_RESERVED     = (__force blk_mq_req_flags_t)(1 << 1),
 265         /* allocate internal/sched tag */
 266         BLK_MQ_REQ_INTERNAL     = (__force blk_mq_req_flags_t)(1 << 2),
 267         /* set RQF_PREEMPT */
 268         BLK_MQ_REQ_PREEMPT      = (__force blk_mq_req_flags_t)(1 << 3),
 269 };
 270
 271 struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
 272                 blk_mq_req_flags_t flags);
 273 struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
 274                 unsigned int op, blk_mq_req_flags_t flags,
 275                 unsigned int hctx_idx);
 276 struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag);
 277
 278 enum {
 279         BLK_MQ_UNIQUE_TAG_BITS = 16,
 280         BLK_MQ_UNIQUE_TAG_MASK = (1 << BLK_MQ_UNIQUE_TAG_BITS) - 1,
 281 };
 282
 283 u32 blk_mq_unique_tag(struct request *rq);
 284
 285 static inline u16 blk_mq_unique_tag_to_hwq(u32 unique_tag)
 286 {
 287         return unique_tag >> BLK_MQ_UNIQUE_TAG_BITS;
 288 }
 289
 290 static inline u16 blk_mq_unique_tag_to_tag(u32 unique_tag)
 291 {
 292         return unique_tag & BLK_MQ_UNIQUE_TAG_MASK;
 293 }
 294
 295
 296 int blk_mq_request_started(struct request *rq);
 297 void blk_mq_start_request(struct request *rq);
 298 void blk_mq_end_request(struct request *rq, blk_status_t error);
 299 void __blk_mq_end_request(struct request *rq, blk_status_t error);
 300
 301 void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list);
 302 void blk_mq_kick_requeue_list(struct request_queue *q);
 303 void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs);
 304 bool blk_mq_complete_request(struct request *rq);
 305 void blk_mq_complete_request_sync(struct request *rq);
 306 bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list,
 307                            struct bio *bio);
 308 bool blk_mq_queue_stopped(struct request_queue *q);
 309 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);
 310 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx);
 311 void blk_mq_stop_hw_queues(struct request_queue *q);
 312 void blk_mq_start_hw_queues(struct request_queue *q);
 313 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
 314 void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async);
 315 void blk_mq_quiesce_queue(struct request_queue *q);
 316 void blk_mq_unquiesce_queue(struct request_queue *q);
 317 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs);
 318 bool blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
 319 void blk_mq_run_hw_queues(struct request_queue *q, bool async);
 320 void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
 321                 busy_tag_iter_fn *fn, void *priv);
 322 void blk_mq_freeze_queue(struct request_queue *q);
 323 void blk_mq_unfreeze_queue(struct request_queue *q);
 324 void blk_freeze_queue_start(struct request_queue *q);
 325 void blk_mq_freeze_queue_wait(struct request_queue *q);
 326 int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
 327                                      unsigned long timeout);
 328
 329 int blk_mq_map_queues(struct blk_mq_queue_map *qmap);
 330 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
 331
 332 void blk_mq_quiesce_queue_nowait(struct request_queue *q);
 333
 334 unsigned int blk_mq_rq_cpu(struct request *rq);
 335
 336 /*
 337  * Driver command data is immediately after the request. So subtract request
 338  * size to get back to the original request, add request size to get the PDU.
 339  */
 340 static inline struct request *blk_mq_rq_from_pdu(void *pdu)
 341 {
 342         return pdu - sizeof(struct request);
 343 }
 344 static inline void *blk_mq_rq_to_pdu(struct request *rq)
 345 {
 346         return rq + 1;
 347 }
 348
 349 #define queue_for_each_hw_ctx(q, hctx, i)                               \
 350         for ((i) = 0; (i) < (q)->nr_hw_queues &&                        \
 351              ({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++)
 352
 353 #define hctx_for_each_ctx(hctx, ctx, i)                                 \
 354         for ((i) = 0; (i) < (hctx)->nr_ctx &&                           \
 355              ({ ctx = (hctx)->ctxs[(i)]; 1; }); (i)++)
 356
 357 static inline blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx,
 358                 struct request *rq)
 359 {
 360         if (rq->tag != -1)
 361                 return rq->tag | (hctx->queue_num << BLK_QC_T_SHIFT);
 362
 363         return rq->internal_tag | (hctx->queue_num << BLK_QC_T_SHIFT) |
 364                         BLK_QC_T_INTERNAL;
 365 }
 366
 367 #endif