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 elv_register_queue(struct request_queue *q);
 235 void elv_unregister_queue(struct request_queue *q);
 236
 237 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
 238
 239 #ifdef CONFIG_FAIL_IO_TIMEOUT
 240 int blk_should_fake_timeout(struct request_queue *);
 241 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 242 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 243                                 const char *, size_t);
 244 #else
 245 static inline int blk_should_fake_timeout(struct request_queue *q)
 246 {
 247         return 0;
 248 }
 249 #endif
 250
 251 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 252                      struct bio *bio);
 253 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 254                       struct bio *bio);
 255 struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
 256 struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
 257 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 258                                 struct request *next);
 259 void blk_recalc_rq_segments(struct request *rq);
 260 void blk_rq_set_mixed_merge(struct request *rq);
 261 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 262 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
 263
 264 void blk_queue_congestion_threshold(struct request_queue *q);
 265
 266 int blk_dev_init(void);
 267
 268
 269 /*
 270  * Return the threshold (number of used requests) at which the queue is
 271  * considered to be congested.  It include a little hysteresis to keep the
 272  * context switch rate down.
 273  */
 274 static inline int queue_congestion_on_threshold(struct request_queue *q)
 275 {
 276         return q->nr_congestion_on;
 277 }
 278
 279 /*
 280  * The threshold at which a queue is considered to be uncongested
 281  */
 282 static inline int queue_congestion_off_threshold(struct request_queue *q)
 283 {
 284         return q->nr_congestion_off;
 285 }
 286
 287 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
 288
 289 /*
 290  * Contribute to IO statistics IFF:
 291  *
 292  *      a) it's attached to a gendisk, and
 293  *      b) the queue had IO stats enabled when this request was started, and
 294  *      c) it's a file system request
 295  */
 296 static inline int blk_do_io_stat(struct request *rq)
 297 {
 298         return rq->rq_disk &&
 299                (rq->rq_flags & RQF_IO_STAT) &&
 300                 !blk_rq_is_passthrough(rq);
 301 }
 302
 303 static inline void req_set_nomerge(struct request_queue *q, struct request *req)
 304 {
 305         req->cmd_flags |= REQ_NOMERGE;
 306         if (req == q->last_merge)
 307                 q->last_merge = NULL;
 308 }
 309
 310 /*
 311  * Steal a bit from this field for legacy IO path atomic IO marking. Note that
 312  * setting the deadline clears the bottom bit, potentially clearing the
 313  * completed bit. The user has to be OK with this (current ones are fine).
 314  */
 315 static inline void blk_rq_set_deadline(struct request *rq, unsigned long time)
 316 {
 317         rq->__deadline = time & ~0x1UL;
 318 }
 319
 320 static inline unsigned long blk_rq_deadline(struct request *rq)
 321 {
 322         return rq->__deadline & ~0x1UL;
 323 }
 324
 325 /*
 326  * Internal io_context interface
 327  */
 328 void get_io_context(struct io_context *ioc);
 329 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
 330 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
 331                              gfp_t gfp_mask);
 332 void ioc_clear_queue(struct request_queue *q);
 333
 334 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
 335
 336 /**
 337  * rq_ioc - determine io_context for request allocation
 338  * @bio: request being allocated is for this bio (can be %NULL)
 339  *
 340  * Determine io_context to use for request allocation for @bio.  May return
 341  * %NULL if %current->io_context doesn't exist.
 342  */
 343 static inline struct io_context *rq_ioc(struct bio *bio)
 344 {
 345 #ifdef CONFIG_BLK_CGROUP
 346         if (bio && bio->bi_ioc)
 347                 return bio->bi_ioc;
 348 #endif
 349         return current->io_context;
 350 }
 351
 352 /**
 353  * create_io_context - try to create task->io_context
 354  * @gfp_mask: allocation mask
 355  * @node: allocation node
 356  *
 357  * If %current->io_context is %NULL, allocate a new io_context and install
 358  * it.  Returns the current %current->io_context which may be %NULL if
 359  * allocation failed.
 360  *
 361  * Note that this function can't be called with IRQ disabled because
 362  * task_lock which protects %current->io_context is IRQ-unsafe.
 363  */
 364 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
 365 {
 366         WARN_ON_ONCE(irqs_disabled());
 367         if (unlikely(!current->io_context))
 368                 create_task_io_context(current, gfp_mask, node);
 369         return current->io_context;
 370 }
 371
 372 /*
 373  * Internal throttling interface
 374  */
 375 #ifdef CONFIG_BLK_DEV_THROTTLING
 376 extern void blk_throtl_drain(struct request_queue *q);
 377 extern int blk_throtl_init(struct request_queue *q);
 378 extern void blk_throtl_exit(struct request_queue *q);
 379 extern void blk_throtl_register_queue(struct request_queue *q);
 380 #else /* CONFIG_BLK_DEV_THROTTLING */
 381 static inline void blk_throtl_drain(struct request_queue *q) { }
 382 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
 383 static inline void blk_throtl_exit(struct request_queue *q) { }
 384 static inline void blk_throtl_register_queue(struct request_queue *q) { }
 385 #endif /* CONFIG_BLK_DEV_THROTTLING */
 386 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 387 extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
 388 extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
 389         const char *page, size_t count);
 390 extern void blk_throtl_bio_endio(struct bio *bio);
 391 extern void blk_throtl_stat_add(struct request *rq, u64 time);
 392 #else
 393 static inline void blk_throtl_bio_endio(struct bio *bio) { }
 394 static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
 395 #endif
 396
 397 #ifdef CONFIG_BOUNCE
 398 extern int init_emergency_isa_pool(void);
 399 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 400 #else
 401 static inline int init_emergency_isa_pool(void)
 402 {
 403         return 0;
 404 }
 405 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 406 {
 407 }
 408 #endif /* CONFIG_BOUNCE */
 409
 410 extern void blk_drain_queue(struct request_queue *q);
 411
 412 #endif /* BLK_INTERNAL_H */