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         /*
 126          * Keep these two bits first - not because we depend on the
 127          * value of them, but we do depend on them being in the same
 128          * byte of storage to ensure ordering on writes. Keeping them
 129          * first will achieve that nicely.
 130          */
 131         REQ_ATOM_COMPLETE = 0,
 132         REQ_ATOM_STARTED,
 133
 134         REQ_ATOM_POLL_SLEPT,
 135 };
 136
 137 /*
 138  * EH timer and IO completion will both attempt to 'grab' the request, make
 139  * sure that only one of them succeeds
 140  */
 141 static inline int blk_mark_rq_complete(struct request *rq)
 142 {
 143         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 144 }
 145
 146 static inline void blk_clear_rq_complete(struct request *rq)
 147 {
 148         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 149 }
 150
 151 /*
 152  * Internal elevator interface
 153  */
 154 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
 155
 156 void blk_insert_flush(struct request *rq);
 157
 158 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
 159 {
 160         struct elevator_queue *e = q->elevator;
 161
 162         if (e->type->ops.sq.elevator_activate_req_fn)
 163                 e->type->ops.sq.elevator_activate_req_fn(q, rq);
 164 }
 165
 166 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
 167 {
 168         struct elevator_queue *e = q->elevator;
 169
 170         if (e->type->ops.sq.elevator_deactivate_req_fn)
 171                 e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
 172 }
 173
 174 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
 175
 176 #ifdef CONFIG_FAIL_IO_TIMEOUT
 177 int blk_should_fake_timeout(struct request_queue *);
 178 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 179 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 180                                 const char *, size_t);
 181 #else
 182 static inline int blk_should_fake_timeout(struct request_queue *q)
 183 {
 184         return 0;
 185 }
 186 #endif
 187
 188 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 189                      struct bio *bio);
 190 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 191                       struct bio *bio);
 192 struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
 193 struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
 194 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 195                                 struct request *next);
 196 void blk_recalc_rq_segments(struct request *rq);
 197 void blk_rq_set_mixed_merge(struct request *rq);
 198 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 199 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
 200
 201 void blk_queue_congestion_threshold(struct request_queue *q);
 202
 203 int blk_dev_init(void);
 204
 205
 206 /*
 207  * Return the threshold (number of used requests) at which the queue is
 208  * considered to be congested.  It include a little hysteresis to keep the
 209  * context switch rate down.
 210  */
 211 static inline int queue_congestion_on_threshold(struct request_queue *q)
 212 {
 213         return q->nr_congestion_on;
 214 }
 215
 216 /*
 217  * The threshold at which a queue is considered to be uncongested
 218  */
 219 static inline int queue_congestion_off_threshold(struct request_queue *q)
 220 {
 221         return q->nr_congestion_off;
 222 }
 223
 224 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
 225
 226 /*
 227  * Contribute to IO statistics IFF:
 228  *
 229  *      a) it's attached to a gendisk, and
 230  *      b) the queue had IO stats enabled when this request was started, and
 231  *      c) it's a file system request
 232  */
 233 static inline int blk_do_io_stat(struct request *rq)
 234 {
 235         return rq->rq_disk &&
 236                (rq->rq_flags & RQF_IO_STAT) &&
 237                 !blk_rq_is_passthrough(rq);
 238 }
 239
 240 static inline void req_set_nomerge(struct request_queue *q, struct request *req)
 241 {
 242         req->cmd_flags |= REQ_NOMERGE;
 243         if (req == q->last_merge)
 244                 q->last_merge = NULL;
 245 }
 246
 247 /*
 248  * Internal io_context interface
 249  */
 250 void get_io_context(struct io_context *ioc);
 251 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
 252 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
 253                              gfp_t gfp_mask);
 254 void ioc_clear_queue(struct request_queue *q);
 255
 256 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
 257
 258 /**
 259  * rq_ioc - determine io_context for request allocation
 260  * @bio: request being allocated is for this bio (can be %NULL)
 261  *
 262  * Determine io_context to use for request allocation for @bio.  May return
 263  * %NULL if %current->io_context doesn't exist.
 264  */
 265 static inline struct io_context *rq_ioc(struct bio *bio)
 266 {
 267 #ifdef CONFIG_BLK_CGROUP
 268         if (bio && bio->bi_ioc)
 269                 return bio->bi_ioc;
 270 #endif
 271         return current->io_context;
 272 }
 273
 274 /**
 275  * create_io_context - try to create task->io_context
 276  * @gfp_mask: allocation mask
 277  * @node: allocation node
 278  *
 279  * If %current->io_context is %NULL, allocate a new io_context and install
 280  * it.  Returns the current %current->io_context which may be %NULL if
 281  * allocation failed.
 282  *
 283  * Note that this function can't be called with IRQ disabled because
 284  * task_lock which protects %current->io_context is IRQ-unsafe.
 285  */
 286 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
 287 {
 288         WARN_ON_ONCE(irqs_disabled());
 289         if (unlikely(!current->io_context))
 290                 create_task_io_context(current, gfp_mask, node);
 291         return current->io_context;
 292 }
 293
 294 /*
 295  * Internal throttling interface
 296  */
 297 #ifdef CONFIG_BLK_DEV_THROTTLING
 298 extern void blk_throtl_drain(struct request_queue *q);
 299 extern int blk_throtl_init(struct request_queue *q);
 300 extern void blk_throtl_exit(struct request_queue *q);
 301 extern void blk_throtl_register_queue(struct request_queue *q);
 302 #else /* CONFIG_BLK_DEV_THROTTLING */
 303 static inline void blk_throtl_drain(struct request_queue *q) { }
 304 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
 305 static inline void blk_throtl_exit(struct request_queue *q) { }
 306 static inline void blk_throtl_register_queue(struct request_queue *q) { }
 307 #endif /* CONFIG_BLK_DEV_THROTTLING */
 308 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 309 extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
 310 extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
 311         const char *page, size_t count);
 312 extern void blk_throtl_bio_endio(struct bio *bio);
 313 extern void blk_throtl_stat_add(struct request *rq, u64 time);
 314 #else
 315 static inline void blk_throtl_bio_endio(struct bio *bio) { }
 316 static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
 317 #endif
 318
 319 #ifdef CONFIG_BOUNCE
 320 extern int init_emergency_isa_pool(void);
 321 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 322 #else
 323 static inline int init_emergency_isa_pool(void)
 324 {
 325         return 0;
 326 }
 327 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 328 {
 329 }
 330 #endif /* CONFIG_BOUNCE */
 331
 332 #endif /* BLK_INTERNAL_H */