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 void __generic_unplug_device(struct request_queue *);
  24
  25 /*
  26  * Internal atomic flags for request handling
  27  */
  28 enum rq_atomic_flags {
  29         REQ_ATOM_COMPLETE = 0,
  30 };
  31
  32 /*
  33  * EH timer and IO completion will both attempt to 'grab' the request, make
  34  * sure that only one of them suceeds
  35  */
  36 static inline int blk_mark_rq_complete(struct request *rq)
  37 {
  38         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
  39 }
  40
  41 static inline void blk_clear_rq_complete(struct request *rq)
  42 {
  43         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
  44 }
  45
  46 #ifdef CONFIG_FAIL_IO_TIMEOUT
  47 int blk_should_fake_timeout(struct request_queue *);
  48 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
  49 ssize_t part_timeout_store(struct device *, struct device_attribute *,
  50                                 const char *, size_t);
  51 #else
  52 static inline int blk_should_fake_timeout(struct request_queue *q)
  53 {
  54         return 0;
  55 }
  56 #endif
  57
  58 struct io_context *current_io_context(gfp_t gfp_flags, int node);
  59
  60 int ll_back_merge_fn(struct request_queue *q, struct request *req,
  61                      struct bio *bio);
  62 int ll_front_merge_fn(struct request_queue *q, struct request *req,
  63                       struct bio *bio);
  64 int attempt_back_merge(struct request_queue *q, struct request *rq);
  65 int attempt_front_merge(struct request_queue *q, struct request *rq);
  66 void blk_recalc_rq_segments(struct request *rq);
  67 void blk_recalc_rq_sectors(struct request *rq, int nsect);
  68
  69 void blk_queue_congestion_threshold(struct request_queue *q);
  70
  71 int blk_dev_init(void);
  72
  73 /*
  74  * Return the threshold (number of used requests) at which the queue is
  75  * considered to be congested.  It include a little hysteresis to keep the
  76  * context switch rate down.
  77  */
  78 static inline int queue_congestion_on_threshold(struct request_queue *q)
  79 {
  80         return q->nr_congestion_on;
  81 }
  82
  83 /*
  84  * The threshold at which a queue is considered to be uncongested
  85  */
  86 static inline int queue_congestion_off_threshold(struct request_queue *q)
  87 {
  88         return q->nr_congestion_off;
  89 }
  90
  91 #if defined(CONFIG_BLK_DEV_INTEGRITY)
  92
  93 #define rq_for_each_integrity_segment(bvl, _rq, _iter)          \
  94         __rq_for_each_bio(_iter.bio, _rq)                       \
  95                 bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
  96
  97 #endif /* BLK_DEV_INTEGRITY */
  98
  99 static inline int blk_cpu_to_group(int cpu)
 100 {
 101 #ifdef CONFIG_SCHED_MC
 102         const struct cpumask *mask = cpu_coregroup_mask(cpu);
 103         return cpumask_first(mask);
 104 #elif defined(CONFIG_SCHED_SMT)
 105         return first_cpu(per_cpu(cpu_sibling_map, cpu));
 106 #else
 107         return cpu;
 108 #endif
 109 }
 110
 111 #endif