block/blk.h

   1 #ifndef BLK_INTERNAL_H
   2 #define BLK_INTERNAL_H
   3
   4 #include <linux/idr.h>
   5 #include <linux/blk-mq.h>
   6 #include "blk-mq.h"
   7
   8 /* Amount of time in which a process may batch requests */
   9 #define BLK_BATCH_TIME  (HZ/50UL)
  10
  11 /* Number of requests a "batching" process may submit */
  12 #define BLK_BATCH_REQ   32
  13
  14 /* Max future timer expiry for timeouts */
  15 #define BLK_MAX_TIMEOUT         (5 * HZ)
  16
  17 #ifdef CONFIG_DEBUG_FS
  18 extern struct dentry *blk_debugfs_root;
  19 #endif
  20
  21 struct blk_flush_queue {
  22         unsigned int            flush_queue_delayed:1;
  23         unsigned int            flush_pending_idx:1;
  24         unsigned int            flush_running_idx:1;
  25         unsigned long           flush_pending_since;
  26         struct list_head        flush_queue[2];
  27         struct list_head        flush_data_in_flight;
  28         struct request          *flush_rq;
  29
  30         /*
  31          * flush_rq shares tag with this rq, both can't be active
  32          * at the same time
  33          */
  34         struct request          *orig_rq;
  35         spinlock_t              mq_flush_lock;
  36 };
  37
  38 extern struct kmem_cache *blk_requestq_cachep;
  39 extern struct kmem_cache *request_cachep;
  40 extern struct kobj_type blk_queue_ktype;
  41 extern struct ida blk_queue_ida;
  42
  43 static inline struct blk_flush_queue *blk_get_flush_queue(
  44                 struct request_queue *q, struct blk_mq_ctx *ctx)
  45 {
  46         if (q->mq_ops)
  47                 return blk_mq_map_queue(q, ctx->cpu)->fq;
  48         return q->fq;
  49 }
  50
  51 static inline void __blk_get_queue(struct request_queue *q)
  52 {
  53         kobject_get(&q->kobj);
  54 }
  55
  56 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
  57                 int node, int cmd_size);
  58 void blk_free_flush_queue(struct blk_flush_queue *q);
  59
  60 int blk_init_rl(struct request_list *rl, struct request_queue *q,
  61                 gfp_t gfp_mask);
  62 void blk_exit_rl(struct request_queue *q, struct request_list *rl);
  63 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
  64                         struct bio *bio);
  65 void blk_queue_bypass_start(struct request_queue *q);
  66 void blk_queue_bypass_end(struct request_queue *q);
  67 void blk_dequeue_request(struct request *rq);
  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         REQ_ATOM_COMPLETE = 0,
 127         REQ_ATOM_STARTED,
 128         REQ_ATOM_POLL_SLEPT,
 129 };
 130
 131 /*
 132  * EH timer and IO completion will both attempt to 'grab' the request, make
 133  * sure that only one of them succeeds
 134  */
 135 static inline int blk_mark_rq_complete(struct request *rq)
 136 {
 137         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 138 }
 139
 140 static inline void blk_clear_rq_complete(struct request *rq)
 141 {
 142         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 143 }
 144
 145 /*
 146  * Internal elevator interface
 147  */
 148 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
 149
 150 void blk_insert_flush(struct request *rq);
 151
 152 static inline struct request *__elv_next_request(struct request_queue *q)
 153 {
 154         struct request *rq;
 155         struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
 156
 157         WARN_ON_ONCE(q->mq_ops);
 158
 159         while (1) {
 160                 if (!list_empty(&q->queue_head)) {
 161                         rq = list_entry_rq(q->queue_head.next);
 162                         return rq;
 163                 }
 164
 165                 /*
 166                  * Flush request is running and flush request isn't queueable
 167                  * in the drive, we can hold the queue till flush request is
 168                  * finished. Even we don't do this, driver can't dispatch next
 169                  * requests and will requeue them. And this can improve
 170                  * throughput too. For example, we have request flush1, write1,
 171                  * flush 2. flush1 is dispatched, then queue is hold, write1
 172                  * isn't inserted to queue. After flush1 is finished, flush2
 173                  * will be dispatched. Since disk cache is already clean,
 174                  * flush2 will be finished very soon, so looks like flush2 is
 175                  * folded to flush1.
 176                  * Since the queue is hold, a flag is set to indicate the queue
 177                  * should be restarted later. Please see flush_end_io() for
 178                  * details.
 179                  */
 180                 if (fq->flush_pending_idx != fq->flush_running_idx &&
 181                                 !queue_flush_queueable(q)) {
 182                         fq->flush_queue_delayed = 1;
 183                         return NULL;
 184                 }
 185                 if (unlikely(blk_queue_bypass(q)) ||
 186                     !q->elevator->type->ops.sq.elevator_dispatch_fn(q, 0))
 187                         return NULL;
 188         }
 189 }
 190
 191 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
 192 {
 193         struct elevator_queue *e = q->elevator;
 194
 195         if (e->type->ops.sq.elevator_activate_req_fn)
 196                 e->type->ops.sq.elevator_activate_req_fn(q, rq);
 197 }
 198
 199 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
 200 {
 201         struct elevator_queue *e = q->elevator;
 202
 203         if (e->type->ops.sq.elevator_deactivate_req_fn)
 204                 e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
 205 }
 206
 207 #ifdef CONFIG_FAIL_IO_TIMEOUT
 208 int blk_should_fake_timeout(struct request_queue *);
 209 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 210 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 211                                 const char *, size_t);
 212 #else
 213 static inline int blk_should_fake_timeout(struct request_queue *q)
 214 {
 215         return 0;
 216 }
 217 #endif
 218
 219 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 220                      struct bio *bio);
 221 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 222                       struct bio *bio);
 223 struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
 224 struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
 225 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 226                                 struct request *next);
 227 void blk_recalc_rq_segments(struct request *rq);
 228 void blk_rq_set_mixed_merge(struct request *rq);
 229 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 230 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
 231
 232 void blk_queue_congestion_threshold(struct request_queue *q);
 233
 234 int blk_dev_init(void);
 235
 236
 237 /*
 238  * Return the threshold (number of used requests) at which the queue is
 239  * considered to be congested.  It include a little hysteresis to keep the
 240  * context switch rate down.
 241  */
 242 static inline int queue_congestion_on_threshold(struct request_queue *q)
 243 {
 244         return q->nr_congestion_on;
 245 }
 246
 247 /*
 248  * The threshold at which a queue is considered to be uncongested
 249  */
 250 static inline int queue_congestion_off_threshold(struct request_queue *q)
 251 {
 252         return q->nr_congestion_off;
 253 }
 254
 255 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
 256
 257 /*
 258  * Contribute to IO statistics IFF:
 259  *
 260  *      a) it's attached to a gendisk, and
 261  *      b) the queue had IO stats enabled when this request was started, and
 262  *      c) it's a file system request
 263  */
 264 static inline int blk_do_io_stat(struct request *rq)
 265 {
 266         return rq->rq_disk &&
 267                (rq->rq_flags & RQF_IO_STAT) &&
 268                 !blk_rq_is_passthrough(rq);
 269 }
 270
 271 static inline void req_set_nomerge(struct request_queue *q, struct request *req)
 272 {
 273         req->cmd_flags |= REQ_NOMERGE;
 274         if (req == q->last_merge)
 275                 q->last_merge = NULL;
 276 }
 277
 278 /*
 279  * Internal io_context interface
 280  */
 281 void get_io_context(struct io_context *ioc);
 282 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
 283 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
 284                              gfp_t gfp_mask);
 285 void ioc_clear_queue(struct request_queue *q);
 286
 287 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
 288
 289 /**
 290  * rq_ioc - determine io_context for request allocation
 291  * @bio: request being allocated is for this bio (can be %NULL)
 292  *
 293  * Determine io_context to use for request allocation for @bio.  May return
 294  * %NULL if %current->io_context doesn't exist.
 295  */
 296 static inline struct io_context *rq_ioc(struct bio *bio)
 297 {
 298 #ifdef CONFIG_BLK_CGROUP
 299         if (bio && bio->bi_ioc)
 300                 return bio->bi_ioc;
 301 #endif
 302         return current->io_context;
 303 }
 304
 305 /**
 306  * create_io_context - try to create task->io_context
 307  * @gfp_mask: allocation mask
 308  * @node: allocation node
 309  *
 310  * If %current->io_context is %NULL, allocate a new io_context and install
 311  * it.  Returns the current %current->io_context which may be %NULL if
 312  * allocation failed.
 313  *
 314  * Note that this function can't be called with IRQ disabled because
 315  * task_lock which protects %current->io_context is IRQ-unsafe.
 316  */
 317 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
 318 {
 319         WARN_ON_ONCE(irqs_disabled());
 320         if (unlikely(!current->io_context))
 321                 create_task_io_context(current, gfp_mask, node);
 322         return current->io_context;
 323 }
 324
 325 /*
 326  * Internal throttling interface
 327  */
 328 #ifdef CONFIG_BLK_DEV_THROTTLING
 329 extern void blk_throtl_drain(struct request_queue *q);
 330 extern int blk_throtl_init(struct request_queue *q);
 331 extern void blk_throtl_exit(struct request_queue *q);
 332 extern void blk_throtl_register_queue(struct request_queue *q);
 333 #else /* CONFIG_BLK_DEV_THROTTLING */
 334 static inline void blk_throtl_drain(struct request_queue *q) { }
 335 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
 336 static inline void blk_throtl_exit(struct request_queue *q) { }
 337 static inline void blk_throtl_register_queue(struct request_queue *q) { }
 338 #endif /* CONFIG_BLK_DEV_THROTTLING */
 339 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 340 extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
 341 extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
 342         const char *page, size_t count);
 343 extern void blk_throtl_bio_endio(struct bio *bio);
 344 extern void blk_throtl_stat_add(struct request *rq, u64 time);
 345 #else
 346 static inline void blk_throtl_bio_endio(struct bio *bio) { }
 347 static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
 348 #endif
 349
 350 #ifdef CONFIG_BOUNCE
 351 extern int init_emergency_isa_pool(void);
 352 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 353 #else
 354 static inline int init_emergency_isa_pool(void)
 355 {
 356         return 0;
 357 }
 358 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 359 {
 360 }
 361 #endif /* CONFIG_BOUNCE */
 362
 363 #endif /* BLK_INTERNAL_H */