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_queue_free_tags(struct request_queue *q);
  68 void blk_freeze_queue(struct request_queue *q);
  69
  70 static inline void blk_queue_enter_live(struct request_queue *q)
  71 {
  72         /*
  73          * Given that running in generic_make_request() context
  74          * guarantees that a live reference against q_usage_counter has
  75          * been established, further references under that same context
  76          * need not check that the queue has been frozen (marked dead).
  77          */
  78         percpu_ref_get(&q->q_usage_counter);
  79 }
  80
  81 #ifdef CONFIG_BLK_DEV_INTEGRITY
  82 void blk_flush_integrity(void);
  83 bool __bio_integrity_endio(struct bio *);
  84 static inline bool bio_integrity_endio(struct bio *bio)
  85 {
  86         if (bio_integrity(bio))
  87                 return __bio_integrity_endio(bio);
  88         return true;
  89 }
  90 #else
  91 static inline void blk_flush_integrity(void)
  92 {
  93 }
  94 static inline bool bio_integrity_endio(struct bio *bio)
  95 {
  96         return true;
  97 }
  98 #endif
  99
 100 void blk_timeout_work(struct work_struct *work);
 101 unsigned long blk_rq_timeout(unsigned long timeout);
 102 void blk_add_timer(struct request *req);
 103 void blk_delete_timer(struct request *);
 104
 105
 106 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
 107                              struct bio *bio);
 108 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
 109                             struct bio *bio);
 110 bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
 111                 struct bio *bio);
 112 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
 113                             unsigned int *request_count,
 114                             struct request **same_queue_rq);
 115 unsigned int blk_plug_queued_count(struct request_queue *q);
 116
 117 void blk_account_io_start(struct request *req, bool new_io);
 118 void blk_account_io_completion(struct request *req, unsigned int bytes);
 119 void blk_account_io_done(struct request *req);
 120
 121 /*
 122  * Internal atomic flags for request handling
 123  */
 124 enum rq_atomic_flags {
 125         REQ_ATOM_COMPLETE = 0,
 126         REQ_ATOM_STARTED,
 127         REQ_ATOM_POLL_SLEPT,
 128 };
 129
 130 /*
 131  * EH timer and IO completion will both attempt to 'grab' the request, make
 132  * sure that only one of them succeeds
 133  */
 134 static inline int blk_mark_rq_complete(struct request *rq)
 135 {
 136         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 137 }
 138
 139 static inline void blk_clear_rq_complete(struct request *rq)
 140 {
 141         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 142 }
 143
 144 /*
 145  * Internal elevator interface
 146  */
 147 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
 148
 149 void blk_insert_flush(struct request *rq);
 150
 151 static inline struct request *__elv_next_request(struct request_queue *q)
 152 {
 153         struct request *rq;
 154         struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
 155
 156         WARN_ON_ONCE(q->mq_ops);
 157
 158         while (1) {
 159                 if (!list_empty(&q->queue_head)) {
 160                         rq = list_entry_rq(q->queue_head.next);
 161                         return rq;
 162                 }
 163
 164                 /*
 165                  * Flush request is running and flush request isn't queueable
 166                  * in the drive, we can hold the queue till flush request is
 167                  * finished. Even we don't do this, driver can't dispatch next
 168                  * requests and will requeue them. And this can improve
 169                  * throughput too. For example, we have request flush1, write1,
 170                  * flush 2. flush1 is dispatched, then queue is hold, write1
 171                  * isn't inserted to queue. After flush1 is finished, flush2
 172                  * will be dispatched. Since disk cache is already clean,
 173                  * flush2 will be finished very soon, so looks like flush2 is
 174                  * folded to flush1.
 175                  * Since the queue is hold, a flag is set to indicate the queue
 176                  * should be restarted later. Please see flush_end_io() for
 177                  * details.
 178                  */
 179                 if (fq->flush_pending_idx != fq->flush_running_idx &&
 180                                 !queue_flush_queueable(q)) {
 181                         fq->flush_queue_delayed = 1;
 182                         return NULL;
 183                 }
 184                 if (unlikely(blk_queue_bypass(q)) ||
 185                     !q->elevator->type->ops.sq.elevator_dispatch_fn(q, 0))
 186                         return NULL;
 187         }
 188 }
 189
 190 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
 191 {
 192         struct elevator_queue *e = q->elevator;
 193
 194         if (e->type->ops.sq.elevator_activate_req_fn)
 195                 e->type->ops.sq.elevator_activate_req_fn(q, rq);
 196 }
 197
 198 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
 199 {
 200         struct elevator_queue *e = q->elevator;
 201
 202         if (e->type->ops.sq.elevator_deactivate_req_fn)
 203                 e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
 204 }
 205
 206 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
 207
 208 #ifdef CONFIG_FAIL_IO_TIMEOUT
 209 int blk_should_fake_timeout(struct request_queue *);
 210 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 211 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 212                                 const char *, size_t);
 213 #else
 214 static inline int blk_should_fake_timeout(struct request_queue *q)
 215 {
 216         return 0;
 217 }
 218 #endif
 219
 220 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 221                      struct bio *bio);
 222 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 223                       struct bio *bio);
 224 struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
 225 struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
 226 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 227                                 struct request *next);
 228 void blk_recalc_rq_segments(struct request *rq);
 229 void blk_rq_set_mixed_merge(struct request *rq);
 230 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 231 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
 232
 233 void blk_queue_congestion_threshold(struct request_queue *q);
 234
 235 int blk_dev_init(void);
 236
 237
 238 /*
 239  * Return the threshold (number of used requests) at which the queue is
 240  * considered to be congested.  It include a little hysteresis to keep the
 241  * context switch rate down.
 242  */
 243 static inline int queue_congestion_on_threshold(struct request_queue *q)
 244 {
 245         return q->nr_congestion_on;
 246 }
 247
 248 /*
 249  * The threshold at which a queue is considered to be uncongested
 250  */
 251 static inline int queue_congestion_off_threshold(struct request_queue *q)
 252 {
 253         return q->nr_congestion_off;
 254 }
 255
 256 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
 257
 258 /*
 259  * Contribute to IO statistics IFF:
 260  *
 261  *      a) it's attached to a gendisk, and
 262  *      b) the queue had IO stats enabled when this request was started, and
 263  *      c) it's a file system request
 264  */
 265 static inline int blk_do_io_stat(struct request *rq)
 266 {
 267         return rq->rq_disk &&
 268                (rq->rq_flags & RQF_IO_STAT) &&
 269                 !blk_rq_is_passthrough(rq);
 270 }
 271
 272 static inline void req_set_nomerge(struct request_queue *q, struct request *req)
 273 {
 274         req->cmd_flags |= REQ_NOMERGE;
 275         if (req == q->last_merge)
 276                 q->last_merge = NULL;
 277 }
 278
 279 /*
 280  * Internal io_context interface
 281  */
 282 void get_io_context(struct io_context *ioc);
 283 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
 284 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
 285                              gfp_t gfp_mask);
 286 void ioc_clear_queue(struct request_queue *q);
 287
 288 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
 289
 290 /**
 291  * rq_ioc - determine io_context for request allocation
 292  * @bio: request being allocated is for this bio (can be %NULL)
 293  *
 294  * Determine io_context to use for request allocation for @bio.  May return
 295  * %NULL if %current->io_context doesn't exist.
 296  */
 297 static inline struct io_context *rq_ioc(struct bio *bio)
 298 {
 299 #ifdef CONFIG_BLK_CGROUP
 300         if (bio && bio->bi_ioc)
 301                 return bio->bi_ioc;
 302 #endif
 303         return current->io_context;
 304 }
 305
 306 /**
 307  * create_io_context - try to create task->io_context
 308  * @gfp_mask: allocation mask
 309  * @node: allocation node
 310  *
 311  * If %current->io_context is %NULL, allocate a new io_context and install
 312  * it.  Returns the current %current->io_context which may be %NULL if
 313  * allocation failed.
 314  *
 315  * Note that this function can't be called with IRQ disabled because
 316  * task_lock which protects %current->io_context is IRQ-unsafe.
 317  */
 318 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
 319 {
 320         WARN_ON_ONCE(irqs_disabled());
 321         if (unlikely(!current->io_context))
 322                 create_task_io_context(current, gfp_mask, node);
 323         return current->io_context;
 324 }
 325
 326 /*
 327  * Internal throttling interface
 328  */
 329 #ifdef CONFIG_BLK_DEV_THROTTLING
 330 extern void blk_throtl_drain(struct request_queue *q);
 331 extern int blk_throtl_init(struct request_queue *q);
 332 extern void blk_throtl_exit(struct request_queue *q);
 333 extern void blk_throtl_register_queue(struct request_queue *q);
 334 #else /* CONFIG_BLK_DEV_THROTTLING */
 335 static inline void blk_throtl_drain(struct request_queue *q) { }
 336 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
 337 static inline void blk_throtl_exit(struct request_queue *q) { }
 338 static inline void blk_throtl_register_queue(struct request_queue *q) { }
 339 #endif /* CONFIG_BLK_DEV_THROTTLING */
 340 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 341 extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
 342 extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
 343         const char *page, size_t count);
 344 extern void blk_throtl_bio_endio(struct bio *bio);
 345 extern void blk_throtl_stat_add(struct request *rq, u64 time);
 346 #else
 347 static inline void blk_throtl_bio_endio(struct bio *bio) { }
 348 static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
 349 #endif
 350
 351 #ifdef CONFIG_BOUNCE
 352 extern int init_emergency_isa_pool(void);
 353 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 354 #else
 355 static inline int init_emergency_isa_pool(void)
 356 {
 357         return 0;
 358 }
 359 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 360 {
 361 }
 362 #endif /* CONFIG_BOUNCE */
 363
 364 #endif /* BLK_INTERNAL_H */