block/blk.h

   1 #ifndef BLK_INTERNAL_H
   2 #define BLK_INTERNAL_H
   3
   4 /* Amount of time in which a process may batch requests */
   5 #define BLK_BATCH_TIME  (HZ/50UL)
   6
   7 /* Number of requests a "batching" process may submit */
   8 #define BLK_BATCH_REQ   32
   9
  10 extern struct kmem_cache *blk_requestq_cachep;
  11 extern struct kobj_type blk_queue_ktype;
  12
  13 void init_request_from_bio(struct request *req, struct bio *bio);
  14 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
  15                         struct bio *bio);
  16 void __blk_queue_free_tags(struct request_queue *q);
  17
  18 void blk_unplug_work(struct work_struct *work);
  19 void blk_unplug_timeout(unsigned long data);
  20 void blk_rq_timed_out_timer(unsigned long data);
  21 void blk_delete_timer(struct request *);
  22 void blk_add_timer(struct request *);
  23
  24 /*
  25  * Internal atomic flags for request handling
  26  */
  27 enum rq_atomic_flags {
  28         REQ_ATOM_COMPLETE = 0,
  29 };
  30
  31 /*
  32  * EH timer and IO completion will both attempt to 'grab' the request, make
  33  * sure that only one of them suceeds
  34  */
  35 static inline int blk_mark_rq_complete(struct request *rq)
  36 {
  37         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
  38 }
  39
  40 static inline void blk_clear_rq_complete(struct request *rq)
  41 {
  42         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
  43 }
  44
  45 #ifdef CONFIG_FAIL_IO_TIMEOUT
  46 int blk_should_fake_timeout(struct request_queue *);
  47 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
  48 ssize_t part_timeout_store(struct device *, struct device_attribute *,
  49                                 const char *, size_t);
  50 #else
  51 static inline int blk_should_fake_timeout(struct request_queue *q)
  52 {
  53         return 0;
  54 }
  55 #endif
  56
  57 struct io_context *current_io_context(gfp_t gfp_flags, int node);
  58
  59 int ll_back_merge_fn(struct request_queue *q, struct request *req,
  60                      struct bio *bio);
  61 int ll_front_merge_fn(struct request_queue *q, struct request *req,
  62                       struct bio *bio);
  63 int attempt_back_merge(struct request_queue *q, struct request *rq);
  64 int attempt_front_merge(struct request_queue *q, struct request *rq);
  65 void blk_recalc_rq_segments(struct request *rq);
  66 void blk_recalc_rq_sectors(struct request *rq, int nsect);
  67
  68 void blk_queue_congestion_threshold(struct request_queue *q);
  69
  70 int blk_dev_init(void);
  71
  72 /*
  73  * Return the threshold (number of used requests) at which the queue is
  74  * considered to be congested.  It include a little hysteresis to keep the
  75  * context switch rate down.
  76  */
  77 static inline int queue_congestion_on_threshold(struct request_queue *q)
  78 {
  79         return q->nr_congestion_on;
  80 }
  81
  82 /*
  83  * The threshold at which a queue is considered to be uncongested
  84  */
  85 static inline int queue_congestion_off_threshold(struct request_queue *q)
  86 {
  87         return q->nr_congestion_off;
  88 }
  89
  90 #if defined(CONFIG_BLK_DEV_INTEGRITY)
  91
  92 #define rq_for_each_integrity_segment(bvl, _rq, _iter)          \
  93         __rq_for_each_bio(_iter.bio, _rq)                       \
  94                 bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
  95
  96 #endif /* BLK_DEV_INTEGRITY */
  97
  98 static inline int blk_cpu_to_group(int cpu)
  99 {
 100 #ifdef CONFIG_SCHED_MC
 101         cpumask_t mask = cpu_coregroup_map(cpu);
 102         return first_cpu(mask);
 103 #elif defined(CONFIG_SCHED_SMT)
 104         return first_cpu(per_cpu(cpu_sibling_map, cpu));
 105 #else
 106         return cpu;
 107 #endif
 108 }
 109
 110 #endif