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 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
  17                       struct bio *bio);
  18 void blk_dequeue_request(struct request *rq);
  19 void __blk_queue_free_tags(struct request_queue *q);
  20
  21 void blk_unplug_work(struct work_struct *work);
  22 void blk_unplug_timeout(unsigned long data);
  23 void blk_rq_timed_out_timer(unsigned long data);
  24 void blk_delete_timer(struct request *);
  25 void blk_add_timer(struct request *);
  26 void __generic_unplug_device(struct request_queue *);
  27
  28 /*
  29  * Internal atomic flags for request handling
  30  */
  31 enum rq_atomic_flags {
  32         REQ_ATOM_COMPLETE = 0,
  33 };
  34
  35 /*
  36  * EH timer and IO completion will both attempt to 'grab' the request, make
  37  * sure that only one of them suceeds
  38  */
  39 static inline int blk_mark_rq_complete(struct request *rq)
  40 {
  41         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
  42 }
  43
  44 static inline void blk_clear_rq_complete(struct request *rq)
  45 {
  46         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
  47 }
  48
  49 /*
  50  * Internal elevator interface
  51  */
  52 #define ELV_ON_HASH(rq)         (!hlist_unhashed(&(rq)->hash))
  53
  54 static inline struct request *__elv_next_request(struct request_queue *q)
  55 {
  56         struct request *rq;
  57
  58         while (1) {
  59                 while (!list_empty(&q->queue_head)) {
  60                         rq = list_entry_rq(q->queue_head.next);
  61                         if (blk_do_ordered(q, &rq))
  62                                 return rq;
  63                 }
  64
  65                 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
  66                     !q->elevator->ops->elevator_dispatch_fn(q, 0))
  67                         return NULL;
  68         }
  69 }
  70
  71 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
  72 {
  73         struct elevator_queue *e = q->elevator;
  74
  75         if (e->ops->elevator_activate_req_fn)
  76                 e->ops->elevator_activate_req_fn(q, rq);
  77 }
  78
  79 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
  80 {
  81         struct elevator_queue *e = q->elevator;
  82
  83         if (e->ops->elevator_deactivate_req_fn)
  84                 e->ops->elevator_deactivate_req_fn(q, rq);
  85 }
  86
  87 #ifdef CONFIG_FAIL_IO_TIMEOUT
  88 int blk_should_fake_timeout(struct request_queue *);
  89 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
  90 ssize_t part_timeout_store(struct device *, struct device_attribute *,
  91                                 const char *, size_t);
  92 #else
  93 static inline int blk_should_fake_timeout(struct request_queue *q)
  94 {
  95         return 0;
  96 }
  97 #endif
  98
  99 struct io_context *current_io_context(gfp_t gfp_flags, int node);
 100
 101 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 102                      struct bio *bio);
 103 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 104                       struct bio *bio);
 105 int attempt_back_merge(struct request_queue *q, struct request *rq);
 106 int attempt_front_merge(struct request_queue *q, struct request *rq);
 107 void blk_recalc_rq_segments(struct request *rq);
 108 void blk_rq_set_mixed_merge(struct request *rq);
 109
 110 void blk_queue_congestion_threshold(struct request_queue *q);
 111
 112 int blk_dev_init(void);
 113
 114 void elv_quiesce_start(struct request_queue *q);
 115 void elv_quiesce_end(struct request_queue *q);
 116
 117
 118 /*
 119  * Return the threshold (number of used requests) at which the queue is
 120  * considered to be congested.  It include a little hysteresis to keep the
 121  * context switch rate down.
 122  */
 123 static inline int queue_congestion_on_threshold(struct request_queue *q)
 124 {
 125         return q->nr_congestion_on;
 126 }
 127
 128 /*
 129  * The threshold at which a queue is considered to be uncongested
 130  */
 131 static inline int queue_congestion_off_threshold(struct request_queue *q)
 132 {
 133         return q->nr_congestion_off;
 134 }
 135
 136 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 137
 138 #define rq_for_each_integrity_segment(bvl, _rq, _iter)          \
 139         __rq_for_each_bio(_iter.bio, _rq)                       \
 140                 bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
 141
 142 #endif /* BLK_DEV_INTEGRITY */
 143
 144 static inline int blk_cpu_to_group(int cpu)
 145 {
 146 #ifdef CONFIG_SCHED_MC
 147         const struct cpumask *mask = cpu_coregroup_mask(cpu);
 148         return cpumask_first(mask);
 149 #elif defined(CONFIG_SCHED_SMT)
 150         return cpumask_first(topology_thread_cpumask(cpu));
 151 #else
 152         return cpu;
 153 #endif
 154 }
 155
 156 /*
 157  * Contribute to IO statistics IFF:
 158  *
 159  *      a) it's attached to a gendisk, and
 160  *      b) the queue had IO stats enabled when this request was started, and
 161  *      c) it's a file system request or a discard request
 162  */
 163 static inline int blk_do_io_stat(struct request *rq)
 164 {
 165         return rq->rq_disk && blk_rq_io_stat(rq) &&
 166                (blk_fs_request(rq) || blk_discard_rq(rq));
 167 }
 168
 169 #endif