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 /*
  47  * Internal elevator interface
  48  */
  49 #define ELV_ON_HASH(rq)         (!hlist_unhashed(&(rq)->hash))
  50
  51 static inline struct request *__elv_next_request(struct request_queue *q)
  52 {
  53         struct request *rq;
  54
  55         while (1) {
  56                 while (!list_empty(&q->queue_head)) {
  57                         rq = list_entry_rq(q->queue_head.next);
  58                         if (blk_do_ordered(q, &rq))
  59                                 return rq;
  60                 }
  61
  62                 if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
  63                         return NULL;
  64         }
  65 }
  66
  67 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
  68 {
  69         struct elevator_queue *e = q->elevator;
  70
  71         if (e->ops->elevator_activate_req_fn)
  72                 e->ops->elevator_activate_req_fn(q, rq);
  73 }
  74
  75 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
  76 {
  77         struct elevator_queue *e = q->elevator;
  78
  79         if (e->ops->elevator_deactivate_req_fn)
  80                 e->ops->elevator_deactivate_req_fn(q, rq);
  81 }
  82
  83 #ifdef CONFIG_FAIL_IO_TIMEOUT
  84 int blk_should_fake_timeout(struct request_queue *);
  85 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
  86 ssize_t part_timeout_store(struct device *, struct device_attribute *,
  87                                 const char *, size_t);
  88 #else
  89 static inline int blk_should_fake_timeout(struct request_queue *q)
  90 {
  91         return 0;
  92 }
  93 #endif
  94
  95 struct io_context *current_io_context(gfp_t gfp_flags, int node);
  96
  97 int ll_back_merge_fn(struct request_queue *q, struct request *req,
  98                      struct bio *bio);
  99 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 100                       struct bio *bio);
 101 int attempt_back_merge(struct request_queue *q, struct request *rq);
 102 int attempt_front_merge(struct request_queue *q, struct request *rq);
 103 void blk_recalc_rq_segments(struct request *rq);
 104
 105 void blk_queue_congestion_threshold(struct request_queue *q);
 106
 107 int blk_dev_init(void);
 108
 109 void elv_quiesce_start(struct request_queue *q);
 110 void elv_quiesce_end(struct request_queue *q);
 111
 112
 113 /*
 114  * Return the threshold (number of used requests) at which the queue is
 115  * considered to be congested.  It include a little hysteresis to keep the
 116  * context switch rate down.
 117  */
 118 static inline int queue_congestion_on_threshold(struct request_queue *q)
 119 {
 120         return q->nr_congestion_on;
 121 }
 122
 123 /*
 124  * The threshold at which a queue is considered to be uncongested
 125  */
 126 static inline int queue_congestion_off_threshold(struct request_queue *q)
 127 {
 128         return q->nr_congestion_off;
 129 }
 130
 131 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 132
 133 #define rq_for_each_integrity_segment(bvl, _rq, _iter)          \
 134         __rq_for_each_bio(_iter.bio, _rq)                       \
 135                 bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
 136
 137 #endif /* BLK_DEV_INTEGRITY */
 138
 139 static inline int blk_cpu_to_group(int cpu)
 140 {
 141 #ifdef CONFIG_SCHED_MC
 142         const struct cpumask *mask = cpu_coregroup_mask(cpu);
 143         return cpumask_first(mask);
 144 #elif defined(CONFIG_SCHED_SMT)
 145         return cpumask_first(topology_thread_cpumask(cpu));
 146 #else
 147         return cpu;
 148 #endif
 149 }
 150
 151 /*
 152  * Contribute to IO statistics IFF:
 153  *
 154  *      a) it's attached to a gendisk, and
 155  *      b) the queue had IO stats enabled when this request was started, and
 156  *      c) it's a file system request
 157  */
 158 static inline int blk_do_io_stat(struct request *rq)
 159 {
 160         return rq->rq_disk && blk_rq_io_stat(rq) && blk_fs_request(rq) &&
 161                 blk_discard_rq(rq);
 162 }
 163
 164 #endif