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         unsigned int            nr_expired;
  61
  62         struct hlist_node       cpuhp_dead;
  63         struct kobject          kobj;
  64
  65         unsigned long           poll_considered;
  66         unsigned long           poll_invoked;
  67         unsigned long           poll_success;
  68
  69 #ifdef CONFIG_BLK_DEBUG_FS
  70         struct dentry           *debugfs_dir;
  71         struct dentry           *sched_debugfs_dir;
  72 #endif
  73
  74         /* Must be the last member - see also blk_mq_hw_ctx_size(). */
  75         struct srcu_struct      srcu[0];
  76 };
  77
  78 struct blk_mq_queue_map {
  79         unsigned int *mq_map;
  80         unsigned int nr_queues;
  81         unsigned int queue_offset;
  82 };
  83
  84 enum hctx_type {
  85         HCTX_TYPE_DEFAULT,      /* all I/O not otherwise accounted for */
  86         HCTX_TYPE_READ,         /* just for READ I/O */
  87         HCTX_TYPE_POLL,         /* polled I/O of any kind */
  88
  89         HCTX_MAX_TYPES,
  90 };
  91
  92 struct blk_mq_tag_set {
  93         /*
  94          * map[] holds ctx -> hctx mappings, one map exists for each type
  95          * that the driver wishes to support. There are no restrictions
  96          * on maps being of the same size, and it's perfectly legal to
  97          * share maps between types.
  98          */
  99         struct blk_mq_queue_map map[HCTX_MAX_TYPES];
 100         unsigned int            nr_maps;        /* nr entries in map[] */
 101         const struct blk_mq_ops *ops;
 102         unsigned int            nr_hw_queues;   /* nr hw queues across maps */
 103         unsigned int            queue_depth;    /* max hw supported */
 104         unsigned int            reserved_tags;
 105         unsigned int            cmd_size;       /* per-request extra data */
 106         int                     numa_node;
 107         unsigned int            timeout;
 108         unsigned int            flags;          /* BLK_MQ_F_* */
 109         void                    *driver_data;
 110
 111         struct blk_mq_tags      **tags;
 112
 113         struct mutex            tag_list_lock;
 114         struct list_head        tag_list;
 115 };
 116
 117 struct blk_mq_queue_data {
 118         struct request *rq;
 119         bool last;
 120 };
 121
 122 typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *,
 123                 const struct blk_mq_queue_data *);
 124 typedef void (commit_rqs_fn)(struct blk_mq_hw_ctx *);
 125 typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *);
 126 typedef void (put_budget_fn)(struct blk_mq_hw_ctx *);
 127 typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
 128 typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
 129 typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
 130 typedef int (init_request_fn)(struct blk_mq_tag_set *set, struct request *,
 131                 unsigned int, unsigned int);
 132 typedef void (exit_request_fn)(struct blk_mq_tag_set *set, struct request *,
 133                 unsigned int);
 134
 135 typedef bool (busy_iter_fn)(struct blk_mq_hw_ctx *, struct request *, void *,
 136                 bool);
 137 typedef bool (busy_tag_iter_fn)(struct request *, void *, bool);
 138 typedef int (poll_fn)(struct blk_mq_hw_ctx *);
 139 typedef int (map_queues_fn)(struct blk_mq_tag_set *set);
 140 typedef bool (busy_fn)(struct request_queue *);
 141 typedef void (complete_fn)(struct request *);
 142
 143
 144 struct blk_mq_ops {
 145         /*
 146          * Queue request
 147          */
 148         queue_rq_fn             *queue_rq;
 149
 150         /*
 151          * If a driver uses bd->last to judge when to submit requests to
 152          * hardware, it must define this function. In case of errors that
 153          * make us stop issuing further requests, this hook serves the
 154          * purpose of kicking the hardware (which the last request otherwise
 155          * would have done).
 156          */
 157         commit_rqs_fn           *commit_rqs;
 158
 159         /*
 160          * Reserve budget before queue request, once .queue_rq is
 161          * run, it is driver's responsibility to release the
 162          * reserved budget. Also we have to handle failure case
 163          * of .get_budget for avoiding I/O deadlock.
 164          */
 165         get_budget_fn           *get_budget;
 166         put_budget_fn           *put_budget;
 167
 168         /*
 169          * Called on request timeout
 170          */
 171         timeout_fn              *timeout;
 172
 173         /*
 174          * Called to poll for completion of a specific tag.
 175          */
 176         poll_fn                 *poll;
 177
 178         complete_fn             *complete;
 179
 180         /*
 181          * Called when the block layer side of a hardware queue has been
 182          * set up, allowing the driver to allocate/init matching structures.
 183          * Ditto for exit/teardown.
 184          */
 185         init_hctx_fn            *init_hctx;
 186         exit_hctx_fn            *exit_hctx;
 187
 188         /*
 189          * Called for every command allocated by the block layer to allow
 190          * the driver to set up driver specific data.
 191          *
 192          * Tag greater than or equal to queue_depth is for setting up
 193          * flush request.
 194          *
 195          * Ditto for exit/teardown.
 196          */
 197         init_request_fn         *init_request;
 198         exit_request_fn         *exit_request;
 199         /* Called from inside blk_get_request() */
 200         void (*initialize_rq_fn)(struct request *rq);
 201
 202         /*
 203          * If set, returns whether or not this queue currently is busy
 204          */
 205         busy_fn                 *busy;
 206
 207         map_queues_fn           *map_queues;
 208
 209 #ifdef CONFIG_BLK_DEBUG_FS
 210         /*
 211          * Used by the debugfs implementation to show driver-specific
 212          * information about a request.
 213          */
 214         void (*show_rq)(struct seq_file *m, struct request *rq);
 215 #endif
 216 };
 217
 218 enum {
 219         BLK_MQ_F_SHOULD_MERGE   = 1 << 0,
 220         BLK_MQ_F_TAG_SHARED     = 1 << 1,
 221         BLK_MQ_F_SG_MERGE       = 1 << 2,
 222         BLK_MQ_F_BLOCKING       = 1 << 5,
 223         BLK_MQ_F_NO_SCHED       = 1 << 6,
 224         BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
 225         BLK_MQ_F_ALLOC_POLICY_BITS = 1,
 226
 227         BLK_MQ_S_STOPPED        = 0,
 228         BLK_MQ_S_TAG_ACTIVE     = 1,
 229         BLK_MQ_S_SCHED_RESTART  = 2,
 230
 231         BLK_MQ_MAX_DEPTH        = 10240,
 232
 233         BLK_MQ_CPU_WORK_BATCH   = 8,
 234 };
 235 #define BLK_MQ_FLAG_TO_ALLOC_POLICY(flags) \
 236         ((flags >> BLK_MQ_F_ALLOC_POLICY_START_BIT) & \
 237                 ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1))
 238 #define BLK_ALLOC_POLICY_TO_MQ_FLAG(policy) \
 239         ((policy & ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1)) \
 240                 << BLK_MQ_F_ALLOC_POLICY_START_BIT)
 241
 242 struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *);
 243 struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
 244                                                   struct request_queue *q);
 245 struct request_queue *blk_mq_init_sq_queue(struct blk_mq_tag_set *set,
 246                                                 const struct blk_mq_ops *ops,
 247                                                 unsigned int queue_depth,
 248                                                 unsigned int set_flags);
 249 int blk_mq_register_dev(struct device *, struct request_queue *);
 250 void blk_mq_unregister_dev(struct device *, struct request_queue *);
 251
 252 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set);
 253 void blk_mq_free_tag_set(struct blk_mq_tag_set *set);
 254
 255 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
 256
 257 void blk_mq_free_request(struct request *rq);
 258 bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
 259
 260 bool blk_mq_queue_inflight(struct request_queue *q);
 261
 262 enum {
 263         /* return when out of requests */
 264         BLK_MQ_REQ_NOWAIT       = (__force blk_mq_req_flags_t)(1 << 0),
 265         /* allocate from reserved pool */
 266         BLK_MQ_REQ_RESERVED     = (__force blk_mq_req_flags_t)(1 << 1),
 267         /* allocate internal/sched tag */
 268         BLK_MQ_REQ_INTERNAL     = (__force blk_mq_req_flags_t)(1 << 2),
 269         /* set RQF_PREEMPT */
 270         BLK_MQ_REQ_PREEMPT      = (__force blk_mq_req_flags_t)(1 << 3),
 271 };
 272
 273 struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
 274                 blk_mq_req_flags_t flags);
 275 struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
 276                 unsigned int op, blk_mq_req_flags_t flags,
 277                 unsigned int hctx_idx);
 278 struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag);
 279
 280 enum {
 281         BLK_MQ_UNIQUE_TAG_BITS = 16,
 282         BLK_MQ_UNIQUE_TAG_MASK = (1 << BLK_MQ_UNIQUE_TAG_BITS) - 1,
 283 };
 284
 285 u32 blk_mq_unique_tag(struct request *rq);
 286
 287 static inline u16 blk_mq_unique_tag_to_hwq(u32 unique_tag)
 288 {
 289         return unique_tag >> BLK_MQ_UNIQUE_TAG_BITS;
 290 }
 291
 292 static inline u16 blk_mq_unique_tag_to_tag(u32 unique_tag)
 293 {
 294         return unique_tag & BLK_MQ_UNIQUE_TAG_MASK;
 295 }
 296
 297
 298 int blk_mq_request_started(struct request *rq);
 299 void blk_mq_start_request(struct request *rq);
 300 void blk_mq_end_request(struct request *rq, blk_status_t error);
 301 void __blk_mq_end_request(struct request *rq, blk_status_t error);
 302
 303 void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list);
 304 void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
 305                                 bool kick_requeue_list);
 306 void blk_mq_kick_requeue_list(struct request_queue *q);
 307 void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs);
 308 bool blk_mq_complete_request(struct request *rq);
 309 bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list,
 310                            struct bio *bio);
 311 bool blk_mq_queue_stopped(struct request_queue *q);
 312 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);
 313 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx);
 314 void blk_mq_stop_hw_queues(struct request_queue *q);
 315 void blk_mq_start_hw_queues(struct request_queue *q);
 316 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
 317 void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async);
 318 void blk_mq_quiesce_queue(struct request_queue *q);
 319 void blk_mq_unquiesce_queue(struct request_queue *q);
 320 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs);
 321 bool blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
 322 void blk_mq_run_hw_queues(struct request_queue *q, bool async);
 323 void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
 324                 busy_tag_iter_fn *fn, void *priv);
 325 void blk_mq_freeze_queue(struct request_queue *q);
 326 void blk_mq_unfreeze_queue(struct request_queue *q);
 327 void blk_freeze_queue_start(struct request_queue *q);
 328 void blk_mq_freeze_queue_wait(struct request_queue *q);
 329 int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
 330                                      unsigned long timeout);
 331
 332 int blk_mq_map_queues(struct blk_mq_queue_map *qmap);
 333 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
 334
 335 void blk_mq_quiesce_queue_nowait(struct request_queue *q);
 336
 337 unsigned int blk_mq_rq_cpu(struct request *rq);
 338
 339 /*
 340  * Driver command data is immediately after the request. So subtract request
 341  * size to get back to the original request, add request size to get the PDU.
 342  */
 343 static inline struct request *blk_mq_rq_from_pdu(void *pdu)
 344 {
 345         return pdu - sizeof(struct request);
 346 }
 347 static inline void *blk_mq_rq_to_pdu(struct request *rq)
 348 {
 349         return rq + 1;
 350 }
 351
 352 #define queue_for_each_hw_ctx(q, hctx, i)                               \
 353         for ((i) = 0; (i) < (q)->nr_hw_queues &&                        \
 354              ({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++)
 355
 356 #define hctx_for_each_ctx(hctx, ctx, i)                                 \
 357         for ((i) = 0; (i) < (hctx)->nr_ctx &&                           \
 358              ({ ctx = (hctx)->ctxs[(i)]; 1; }); (i)++)
 359
 360 static inline blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx,
 361                 struct request *rq)
 362 {
 363         if (rq->tag != -1)
 364                 return rq->tag | (hctx->queue_num << BLK_QC_T_SHIFT);
 365
 366         return rq->internal_tag | (hctx->queue_num << BLK_QC_T_SHIFT) |
 367                         BLK_QC_T_INTERNAL;
 368 }
 369
 370 #endif