block/blk.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef BLK_INTERNAL_H
   3 #define BLK_INTERNAL_H
   4
   5 #include <linux/idr.h>
   6 #include <linux/blk-mq.h>
   7 #include "blk-mq.h"
   8
   9 /* Amount of time in which a process may batch requests */
  10 #define BLK_BATCH_TIME  (HZ/50UL)
  11
  12 /* Number of requests a "batching" process may submit */
  13 #define BLK_BATCH_REQ   32
  14
  15 /* Max future timer expiry for timeouts */
  16 #define BLK_MAX_TIMEOUT         (5 * HZ)
  17
  18 #ifdef CONFIG_DEBUG_FS
  19 extern struct dentry *blk_debugfs_root;
  20 #endif
  21
  22 struct blk_flush_queue {
  23         unsigned int            flush_queue_delayed:1;
  24         unsigned int            flush_pending_idx:1;
  25         unsigned int            flush_running_idx:1;
  26         unsigned long           flush_pending_since;
  27         struct list_head        flush_queue[2];
  28         struct list_head        flush_data_in_flight;
  29         struct request          *flush_rq;
  30
  31         /*
  32          * flush_rq shares tag with this rq, both can't be active
  33          * at the same time
  34          */
  35         struct request          *orig_rq;
  36         spinlock_t              mq_flush_lock;
  37 };
  38
  39 extern struct kmem_cache *blk_requestq_cachep;
  40 extern struct kmem_cache *request_cachep;
  41 extern struct kobj_type blk_queue_ktype;
  42 extern struct ida blk_queue_ida;
  43
  44 /*
  45  * @q->queue_lock is set while a queue is being initialized. Since we know
  46  * that no other threads access the queue object before @q->queue_lock has
  47  * been set, it is safe to manipulate queue flags without holding the
  48  * queue_lock if @q->queue_lock == NULL. See also blk_alloc_queue_node() and
  49  * blk_init_allocated_queue().
  50  */
  51 static inline void queue_lockdep_assert_held(struct request_queue *q)
  52 {
  53         if (q->queue_lock)
  54                 lockdep_assert_held(q->queue_lock);
  55 }
  56
  57 static inline void queue_flag_set_unlocked(unsigned int flag,
  58                                            struct request_queue *q)
  59 {
  60         if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
  61             kref_read(&q->kobj.kref))
  62                 lockdep_assert_held(q->queue_lock);
  63         __set_bit(flag, &q->queue_flags);
  64 }
  65
  66 static inline void queue_flag_clear_unlocked(unsigned int flag,
  67                                              struct request_queue *q)
  68 {
  69         if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
  70             kref_read(&q->kobj.kref))
  71                 lockdep_assert_held(q->queue_lock);
  72         __clear_bit(flag, &q->queue_flags);
  73 }
  74
  75 static inline int queue_flag_test_and_clear(unsigned int flag,
  76                                             struct request_queue *q)
  77 {
  78         queue_lockdep_assert_held(q);
  79
  80         if (test_bit(flag, &q->queue_flags)) {
  81                 __clear_bit(flag, &q->queue_flags);
  82                 return 1;
  83         }
  84
  85         return 0;
  86 }
  87
  88 static inline int queue_flag_test_and_set(unsigned int flag,
  89                                           struct request_queue *q)
  90 {
  91         queue_lockdep_assert_held(q);
  92
  93         if (!test_bit(flag, &q->queue_flags)) {
  94                 __set_bit(flag, &q->queue_flags);
  95                 return 0;
  96         }
  97
  98         return 1;
  99 }
 100
 101 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 102 {
 103         queue_lockdep_assert_held(q);
 104         __set_bit(flag, &q->queue_flags);
 105 }
 106
 107 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 108 {
 109         queue_lockdep_assert_held(q);
 110         __clear_bit(flag, &q->queue_flags);
 111 }
 112
 113 static inline struct blk_flush_queue *blk_get_flush_queue(
 114                 struct request_queue *q, struct blk_mq_ctx *ctx)
 115 {
 116         if (q->mq_ops)
 117                 return blk_mq_map_queue(q, ctx->cpu)->fq;
 118         return q->fq;
 119 }
 120
 121 static inline void __blk_get_queue(struct request_queue *q)
 122 {
 123         kobject_get(&q->kobj);
 124 }
 125
 126 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
 127                 int node, int cmd_size);
 128 void blk_free_flush_queue(struct blk_flush_queue *q);
 129
 130 int blk_init_rl(struct request_list *rl, struct request_queue *q,
 131                 gfp_t gfp_mask);
 132 void blk_exit_rl(struct request_queue *q, struct request_list *rl);
 133 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
 134                         struct bio *bio);
 135 void blk_queue_bypass_start(struct request_queue *q);
 136 void blk_queue_bypass_end(struct request_queue *q);
 137 void __blk_queue_free_tags(struct request_queue *q);
 138 void blk_freeze_queue(struct request_queue *q);
 139
 140 static inline void blk_queue_enter_live(struct request_queue *q)
 141 {
 142         /*
 143          * Given that running in generic_make_request() context
 144          * guarantees that a live reference against q_usage_counter has
 145          * been established, further references under that same context
 146          * need not check that the queue has been frozen (marked dead).
 147          */
 148         percpu_ref_get(&q->q_usage_counter);
 149 }
 150
 151 #ifdef CONFIG_BLK_DEV_INTEGRITY
 152 void blk_flush_integrity(void);
 153 bool __bio_integrity_endio(struct bio *);
 154 static inline bool bio_integrity_endio(struct bio *bio)
 155 {
 156         if (bio_integrity(bio))
 157                 return __bio_integrity_endio(bio);
 158         return true;
 159 }
 160 #else
 161 static inline void blk_flush_integrity(void)
 162 {
 163 }
 164 static inline bool bio_integrity_endio(struct bio *bio)
 165 {
 166         return true;
 167 }
 168 #endif
 169
 170 void blk_timeout_work(struct work_struct *work);
 171 unsigned long blk_rq_timeout(unsigned long timeout);
 172 void blk_add_timer(struct request *req);
 173 void blk_delete_timer(struct request *);
 174
 175
 176 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
 177                              struct bio *bio);
 178 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
 179                             struct bio *bio);
 180 bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
 181                 struct bio *bio);
 182 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
 183                             unsigned int *request_count,
 184                             struct request **same_queue_rq);
 185 unsigned int blk_plug_queued_count(struct request_queue *q);
 186
 187 void blk_account_io_start(struct request *req, bool new_io);
 188 void blk_account_io_completion(struct request *req, unsigned int bytes);
 189 void blk_account_io_done(struct request *req, u64 now);
 190
 191 /*
 192  * EH timer and IO completion will both attempt to 'grab' the request, make
 193  * sure that only one of them succeeds. Steal the bottom bit of the
 194  * __deadline field for this.
 195  */
 196 static inline int blk_mark_rq_complete(struct request *rq)
 197 {
 198         return test_and_set_bit(0, &rq->__deadline);
 199 }
 200
 201 static inline void blk_clear_rq_complete(struct request *rq)
 202 {
 203         clear_bit(0, &rq->__deadline);
 204 }
 205
 206 static inline bool blk_rq_is_complete(struct request *rq)
 207 {
 208         return test_bit(0, &rq->__deadline);
 209 }
 210
 211 /*
 212  * Internal elevator interface
 213  */
 214 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
 215
 216 void blk_insert_flush(struct request *rq);
 217
 218 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
 219 {
 220         struct elevator_queue *e = q->elevator;
 221
 222         if (e->type->ops.sq.elevator_activate_req_fn)
 223                 e->type->ops.sq.elevator_activate_req_fn(q, rq);
 224 }
 225
 226 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
 227 {
 228         struct elevator_queue *e = q->elevator;
 229
 230         if (e->type->ops.sq.elevator_deactivate_req_fn)
 231                 e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
 232 }
 233
 234 int elevator_init(struct request_queue *);
 235 int elevator_init_mq(struct request_queue *q);
 236 void elevator_exit(struct request_queue *, struct elevator_queue *);
 237 int elv_register_queue(struct request_queue *q);
 238 void elv_unregister_queue(struct request_queue *q);
 239
 240 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
 241
 242 #ifdef CONFIG_FAIL_IO_TIMEOUT
 243 int blk_should_fake_timeout(struct request_queue *);
 244 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 245 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 246                                 const char *, size_t);
 247 #else
 248 static inline int blk_should_fake_timeout(struct request_queue *q)
 249 {
 250         return 0;
 251 }
 252 #endif
 253
 254 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 255                      struct bio *bio);
 256 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 257                       struct bio *bio);
 258 struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
 259 struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
 260 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 261                                 struct request *next);
 262 void blk_recalc_rq_segments(struct request *rq);
 263 void blk_rq_set_mixed_merge(struct request *rq);
 264 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 265 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
 266
 267 void blk_queue_congestion_threshold(struct request_queue *q);
 268
 269 int blk_dev_init(void);
 270
 271
 272 /*
 273  * Return the threshold (number of used requests) at which the queue is
 274  * considered to be congested.  It include a little hysteresis to keep the
 275  * context switch rate down.
 276  */
 277 static inline int queue_congestion_on_threshold(struct request_queue *q)
 278 {
 279         return q->nr_congestion_on;
 280 }
 281
 282 /*
 283  * The threshold at which a queue is considered to be uncongested
 284  */
 285 static inline int queue_congestion_off_threshold(struct request_queue *q)
 286 {
 287         return q->nr_congestion_off;
 288 }
 289
 290 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
 291
 292 /*
 293  * Contribute to IO statistics IFF:
 294  *
 295  *      a) it's attached to a gendisk, and
 296  *      b) the queue had IO stats enabled when this request was started, and
 297  *      c) it's a file system request
 298  */
 299 static inline int blk_do_io_stat(struct request *rq)
 300 {
 301         return rq->rq_disk &&
 302                (rq->rq_flags & RQF_IO_STAT) &&
 303                 !blk_rq_is_passthrough(rq);
 304 }
 305
 306 static inline void req_set_nomerge(struct request_queue *q, struct request *req)
 307 {
 308         req->cmd_flags |= REQ_NOMERGE;
 309         if (req == q->last_merge)
 310                 q->last_merge = NULL;
 311 }
 312
 313 /*
 314  * Steal a bit from this field for legacy IO path atomic IO marking. Note that
 315  * setting the deadline clears the bottom bit, potentially clearing the
 316  * completed bit. The user has to be OK with this (current ones are fine).
 317  */
 318 static inline void blk_rq_set_deadline(struct request *rq, unsigned long time)
 319 {
 320         rq->__deadline = time & ~0x1UL;
 321 }
 322
 323 static inline unsigned long blk_rq_deadline(struct request *rq)
 324 {
 325         return rq->__deadline & ~0x1UL;
 326 }
 327
 328 /*
 329  * Internal io_context interface
 330  */
 331 void get_io_context(struct io_context *ioc);
 332 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
 333 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
 334                              gfp_t gfp_mask);
 335 void ioc_clear_queue(struct request_queue *q);
 336
 337 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
 338
 339 /**
 340  * rq_ioc - determine io_context for request allocation
 341  * @bio: request being allocated is for this bio (can be %NULL)
 342  *
 343  * Determine io_context to use for request allocation for @bio.  May return
 344  * %NULL if %current->io_context doesn't exist.
 345  */
 346 static inline struct io_context *rq_ioc(struct bio *bio)
 347 {
 348 #ifdef CONFIG_BLK_CGROUP
 349         if (bio && bio->bi_ioc)
 350                 return bio->bi_ioc;
 351 #endif
 352         return current->io_context;
 353 }
 354
 355 /**
 356  * create_io_context - try to create task->io_context
 357  * @gfp_mask: allocation mask
 358  * @node: allocation node
 359  *
 360  * If %current->io_context is %NULL, allocate a new io_context and install
 361  * it.  Returns the current %current->io_context which may be %NULL if
 362  * allocation failed.
 363  *
 364  * Note that this function can't be called with IRQ disabled because
 365  * task_lock which protects %current->io_context is IRQ-unsafe.
 366  */
 367 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
 368 {
 369         WARN_ON_ONCE(irqs_disabled());
 370         if (unlikely(!current->io_context))
 371                 create_task_io_context(current, gfp_mask, node);
 372         return current->io_context;
 373 }
 374
 375 /*
 376  * Internal throttling interface
 377  */
 378 #ifdef CONFIG_BLK_DEV_THROTTLING
 379 extern void blk_throtl_drain(struct request_queue *q);
 380 extern int blk_throtl_init(struct request_queue *q);
 381 extern void blk_throtl_exit(struct request_queue *q);
 382 extern void blk_throtl_register_queue(struct request_queue *q);
 383 #else /* CONFIG_BLK_DEV_THROTTLING */
 384 static inline void blk_throtl_drain(struct request_queue *q) { }
 385 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
 386 static inline void blk_throtl_exit(struct request_queue *q) { }
 387 static inline void blk_throtl_register_queue(struct request_queue *q) { }
 388 #endif /* CONFIG_BLK_DEV_THROTTLING */
 389 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 390 extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
 391 extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
 392         const char *page, size_t count);
 393 extern void blk_throtl_bio_endio(struct bio *bio);
 394 extern void blk_throtl_stat_add(struct request *rq, u64 time);
 395 #else
 396 static inline void blk_throtl_bio_endio(struct bio *bio) { }
 397 static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
 398 #endif
 399
 400 #ifdef CONFIG_BOUNCE
 401 extern int init_emergency_isa_pool(void);
 402 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 403 #else
 404 static inline int init_emergency_isa_pool(void)
 405 {
 406         return 0;
 407 }
 408 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 409 {
 410 }
 411 #endif /* CONFIG_BOUNCE */
 412
 413 extern void blk_drain_queue(struct request_queue *q);
 414
 415 #endif /* BLK_INTERNAL_H */