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 static inline struct blk_flush_queue *blk_get_flush_queue(
  45                 struct request_queue *q, struct blk_mq_ctx *ctx)
  46 {
  47         if (q->mq_ops)
  48                 return blk_mq_map_queue(q, ctx->cpu)->fq;
  49         return q->fq;
  50 }
  51
  52 static inline void __blk_get_queue(struct request_queue *q)
  53 {
  54         kobject_get(&q->kobj);
  55 }
  56
  57 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
  58                 int node, int cmd_size);
  59 void blk_free_flush_queue(struct blk_flush_queue *q);
  60
  61 int blk_init_rl(struct request_list *rl, struct request_queue *q,
  62                 gfp_t gfp_mask);
  63 void blk_exit_rl(struct request_queue *q, struct request_list *rl);
  64 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
  65                         struct bio *bio);
  66 void blk_queue_bypass_start(struct request_queue *q);
  67 void blk_queue_bypass_end(struct request_queue *q);
  68 void __blk_queue_free_tags(struct request_queue *q);
  69 void blk_freeze_queue(struct request_queue *q);
  70
  71 static inline void blk_queue_enter_live(struct request_queue *q)
  72 {
  73         /*
  74          * Given that running in generic_make_request() context
  75          * guarantees that a live reference against q_usage_counter has
  76          * been established, further references under that same context
  77          * need not check that the queue has been frozen (marked dead).
  78          */
  79         percpu_ref_get(&q->q_usage_counter);
  80 }
  81
  82 #ifdef CONFIG_BLK_DEV_INTEGRITY
  83 void blk_flush_integrity(void);
  84 bool __bio_integrity_endio(struct bio *);
  85 static inline bool bio_integrity_endio(struct bio *bio)
  86 {
  87         if (bio_integrity(bio))
  88                 return __bio_integrity_endio(bio);
  89         return true;
  90 }
  91 #else
  92 static inline void blk_flush_integrity(void)
  93 {
  94 }
  95 static inline bool bio_integrity_endio(struct bio *bio)
  96 {
  97         return true;
  98 }
  99 #endif
 100
 101 void blk_timeout_work(struct work_struct *work);
 102 unsigned long blk_rq_timeout(unsigned long timeout);
 103 void blk_add_timer(struct request *req);
 104 void blk_delete_timer(struct request *);
 105
 106
 107 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
 108                              struct bio *bio);
 109 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
 110                             struct bio *bio);
 111 bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
 112                 struct bio *bio);
 113 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
 114                             unsigned int *request_count,
 115                             struct request **same_queue_rq);
 116 unsigned int blk_plug_queued_count(struct request_queue *q);
 117
 118 void blk_account_io_start(struct request *req, bool new_io);
 119 void blk_account_io_completion(struct request *req, unsigned int bytes);
 120 void blk_account_io_done(struct request *req);
 121
 122 /*
 123  * Internal atomic flags for request handling
 124  */
 125 enum rq_atomic_flags {
 126         /*
 127          * Keep these two bits first - not because we depend on the
 128          * value of them, but we do depend on them being in the same
 129          * byte of storage to ensure ordering on writes. Keeping them
 130          * first will achieve that nicely.
 131          */
 132         REQ_ATOM_COMPLETE = 0,
 133         REQ_ATOM_STARTED,
 134
 135         REQ_ATOM_POLL_SLEPT,
 136 };
 137
 138 /*
 139  * EH timer and IO completion will both attempt to 'grab' the request, make
 140  * sure that only one of them succeeds
 141  */
 142 static inline int blk_mark_rq_complete(struct request *rq)
 143 {
 144         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 145 }
 146
 147 static inline void blk_clear_rq_complete(struct request *rq)
 148 {
 149         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 150 }
 151
 152 /*
 153  * Internal elevator interface
 154  */
 155 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
 156
 157 void blk_insert_flush(struct request *rq);
 158
 159 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
 160 {
 161         struct elevator_queue *e = q->elevator;
 162
 163         if (e->type->ops.sq.elevator_activate_req_fn)
 164                 e->type->ops.sq.elevator_activate_req_fn(q, rq);
 165 }
 166
 167 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
 168 {
 169         struct elevator_queue *e = q->elevator;
 170
 171         if (e->type->ops.sq.elevator_deactivate_req_fn)
 172                 e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
 173 }
 174
 175 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
 176
 177 #ifdef CONFIG_FAIL_IO_TIMEOUT
 178 int blk_should_fake_timeout(struct request_queue *);
 179 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 180 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 181                                 const char *, size_t);
 182 #else
 183 static inline int blk_should_fake_timeout(struct request_queue *q)
 184 {
 185         return 0;
 186 }
 187 #endif
 188
 189 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 190                      struct bio *bio);
 191 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 192                       struct bio *bio);
 193 struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
 194 struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
 195 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 196                                 struct request *next);
 197 void blk_recalc_rq_segments(struct request *rq);
 198 void blk_rq_set_mixed_merge(struct request *rq);
 199 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 200 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
 201
 202 void blk_queue_congestion_threshold(struct request_queue *q);
 203
 204 int blk_dev_init(void);
 205
 206
 207 /*
 208  * Return the threshold (number of used requests) at which the queue is
 209  * considered to be congested.  It include a little hysteresis to keep the
 210  * context switch rate down.
 211  */
 212 static inline int queue_congestion_on_threshold(struct request_queue *q)
 213 {
 214         return q->nr_congestion_on;
 215 }
 216
 217 /*
 218  * The threshold at which a queue is considered to be uncongested
 219  */
 220 static inline int queue_congestion_off_threshold(struct request_queue *q)
 221 {
 222         return q->nr_congestion_off;
 223 }
 224
 225 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
 226
 227 /*
 228  * Contribute to IO statistics IFF:
 229  *
 230  *      a) it's attached to a gendisk, and
 231  *      b) the queue had IO stats enabled when this request was started, and
 232  *      c) it's a file system request
 233  */
 234 static inline int blk_do_io_stat(struct request *rq)
 235 {
 236         return rq->rq_disk &&
 237                (rq->rq_flags & RQF_IO_STAT) &&
 238                 !blk_rq_is_passthrough(rq);
 239 }
 240
 241 static inline void req_set_nomerge(struct request_queue *q, struct request *req)
 242 {
 243         req->cmd_flags |= REQ_NOMERGE;
 244         if (req == q->last_merge)
 245                 q->last_merge = NULL;
 246 }
 247
 248 /*
 249  * Internal io_context interface
 250  */
 251 void get_io_context(struct io_context *ioc);
 252 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
 253 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
 254                              gfp_t gfp_mask);
 255 void ioc_clear_queue(struct request_queue *q);
 256
 257 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
 258
 259 /**
 260  * rq_ioc - determine io_context for request allocation
 261  * @bio: request being allocated is for this bio (can be %NULL)
 262  *
 263  * Determine io_context to use for request allocation for @bio.  May return
 264  * %NULL if %current->io_context doesn't exist.
 265  */
 266 static inline struct io_context *rq_ioc(struct bio *bio)
 267 {
 268 #ifdef CONFIG_BLK_CGROUP
 269         if (bio && bio->bi_ioc)
 270                 return bio->bi_ioc;
 271 #endif
 272         return current->io_context;
 273 }
 274
 275 /**
 276  * create_io_context - try to create task->io_context
 277  * @gfp_mask: allocation mask
 278  * @node: allocation node
 279  *
 280  * If %current->io_context is %NULL, allocate a new io_context and install
 281  * it.  Returns the current %current->io_context which may be %NULL if
 282  * allocation failed.
 283  *
 284  * Note that this function can't be called with IRQ disabled because
 285  * task_lock which protects %current->io_context is IRQ-unsafe.
 286  */
 287 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
 288 {
 289         WARN_ON_ONCE(irqs_disabled());
 290         if (unlikely(!current->io_context))
 291                 create_task_io_context(current, gfp_mask, node);
 292         return current->io_context;
 293 }
 294
 295 /*
 296  * Internal throttling interface
 297  */
 298 #ifdef CONFIG_BLK_DEV_THROTTLING
 299 extern void blk_throtl_drain(struct request_queue *q);
 300 extern int blk_throtl_init(struct request_queue *q);
 301 extern void blk_throtl_exit(struct request_queue *q);
 302 extern void blk_throtl_register_queue(struct request_queue *q);
 303 #else /* CONFIG_BLK_DEV_THROTTLING */
 304 static inline void blk_throtl_drain(struct request_queue *q) { }
 305 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
 306 static inline void blk_throtl_exit(struct request_queue *q) { }
 307 static inline void blk_throtl_register_queue(struct request_queue *q) { }
 308 #endif /* CONFIG_BLK_DEV_THROTTLING */
 309 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 310 extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
 311 extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
 312         const char *page, size_t count);
 313 extern void blk_throtl_bio_endio(struct bio *bio);
 314 extern void blk_throtl_stat_add(struct request *rq, u64 time);
 315 #else
 316 static inline void blk_throtl_bio_endio(struct bio *bio) { }
 317 static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
 318 #endif
 319
 320 #ifdef CONFIG_BOUNCE
 321 extern int init_emergency_isa_pool(void);
 322 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 323 #else
 324 static inline int init_emergency_isa_pool(void)
 325 {
 326         return 0;
 327 }
 328 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 329 {
 330 }
 331 #endif /* CONFIG_BOUNCE */
 332
 333 extern void blk_drain_queue(struct request_queue *q);
 334
 335 #endif /* BLK_INTERNAL_H */