blk.h 6.4 KB

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  1. #ifndef BLK_INTERNAL_H
  2. #define BLK_INTERNAL_H
  3. #include <linux/idr.h>
  4. /* Amount of time in which a process may batch requests */
  5. #define BLK_BATCH_TIME (HZ/50UL)
  6. /* Number of requests a "batching" process may submit */
  7. #define BLK_BATCH_REQ 32
  8. extern struct kmem_cache *blk_requestq_cachep;
  9. extern struct kobj_type blk_queue_ktype;
  10. extern struct ida blk_queue_ida;
  11. void init_request_from_bio(struct request *req, struct bio *bio);
  12. void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
  13. struct bio *bio);
  14. int blk_rq_append_bio(struct request_queue *q, struct request *rq,
  15. struct bio *bio);
  16. void blk_drain_queue(struct request_queue *q, bool drain_all);
  17. void blk_dequeue_request(struct request *rq);
  18. void __blk_queue_free_tags(struct request_queue *q);
  19. bool __blk_end_bidi_request(struct request *rq, int error,
  20. unsigned int nr_bytes, unsigned int bidi_bytes);
  21. void blk_rq_timed_out_timer(unsigned long data);
  22. void blk_delete_timer(struct request *);
  23. void blk_add_timer(struct request *);
  24. void __generic_unplug_device(struct request_queue *);
  25. /*
  26. * Internal atomic flags for request handling
  27. */
  28. enum rq_atomic_flags {
  29. REQ_ATOM_COMPLETE = 0,
  30. };
  31. /*
  32. * EH timer and IO completion will both attempt to 'grab' the request, make
  33. * sure that only one of them succeeds
  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. static inline void blk_clear_rq_complete(struct request *rq)
  40. {
  41. clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
  42. }
  43. /*
  44. * Internal elevator interface
  45. */
  46. #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
  47. void blk_insert_flush(struct request *rq);
  48. void blk_abort_flushes(struct request_queue *q);
  49. static inline struct request *__elv_next_request(struct request_queue *q)
  50. {
  51. struct request *rq;
  52. while (1) {
  53. if (!list_empty(&q->queue_head)) {
  54. rq = list_entry_rq(q->queue_head.next);
  55. return rq;
  56. }
  57. /*
  58. * Flush request is running and flush request isn't queueable
  59. * in the drive, we can hold the queue till flush request is
  60. * finished. Even we don't do this, driver can't dispatch next
  61. * requests and will requeue them. And this can improve
  62. * throughput too. For example, we have request flush1, write1,
  63. * flush 2. flush1 is dispatched, then queue is hold, write1
  64. * isn't inserted to queue. After flush1 is finished, flush2
  65. * will be dispatched. Since disk cache is already clean,
  66. * flush2 will be finished very soon, so looks like flush2 is
  67. * folded to flush1.
  68. * Since the queue is hold, a flag is set to indicate the queue
  69. * should be restarted later. Please see flush_end_io() for
  70. * details.
  71. */
  72. if (q->flush_pending_idx != q->flush_running_idx &&
  73. !queue_flush_queueable(q)) {
  74. q->flush_queue_delayed = 1;
  75. return NULL;
  76. }
  77. if (unlikely(blk_queue_dead(q)) ||
  78. !q->elevator->ops->elevator_dispatch_fn(q, 0))
  79. return NULL;
  80. }
  81. }
  82. static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
  83. {
  84. struct elevator_queue *e = q->elevator;
  85. if (e->ops->elevator_activate_req_fn)
  86. e->ops->elevator_activate_req_fn(q, rq);
  87. }
  88. static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
  89. {
  90. struct elevator_queue *e = q->elevator;
  91. if (e->ops->elevator_deactivate_req_fn)
  92. e->ops->elevator_deactivate_req_fn(q, rq);
  93. }
  94. #ifdef CONFIG_FAIL_IO_TIMEOUT
  95. int blk_should_fake_timeout(struct request_queue *);
  96. ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
  97. ssize_t part_timeout_store(struct device *, struct device_attribute *,
  98. const char *, size_t);
  99. #else
  100. static inline int blk_should_fake_timeout(struct request_queue *q)
  101. {
  102. return 0;
  103. }
  104. #endif
  105. struct io_context *current_io_context(gfp_t gfp_flags, int node);
  106. int ll_back_merge_fn(struct request_queue *q, struct request *req,
  107. struct bio *bio);
  108. int ll_front_merge_fn(struct request_queue *q, struct request *req,
  109. struct bio *bio);
  110. int attempt_back_merge(struct request_queue *q, struct request *rq);
  111. int attempt_front_merge(struct request_queue *q, struct request *rq);
  112. int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
  113. struct request *next);
  114. void blk_recalc_rq_segments(struct request *rq);
  115. void blk_rq_set_mixed_merge(struct request *rq);
  116. void blk_queue_congestion_threshold(struct request_queue *q);
  117. int blk_dev_init(void);
  118. void elv_quiesce_start(struct request_queue *q);
  119. void elv_quiesce_end(struct request_queue *q);
  120. /*
  121. * Return the threshold (number of used requests) at which the queue is
  122. * considered to be congested. It include a little hysteresis to keep the
  123. * context switch rate down.
  124. */
  125. static inline int queue_congestion_on_threshold(struct request_queue *q)
  126. {
  127. return q->nr_congestion_on;
  128. }
  129. /*
  130. * The threshold at which a queue is considered to be uncongested
  131. */
  132. static inline int queue_congestion_off_threshold(struct request_queue *q)
  133. {
  134. return q->nr_congestion_off;
  135. }
  136. static inline int blk_cpu_to_group(int cpu)
  137. {
  138. int group = NR_CPUS;
  139. #ifdef CONFIG_SCHED_MC
  140. const struct cpumask *mask = cpu_coregroup_mask(cpu);
  141. group = cpumask_first(mask);
  142. #elif defined(CONFIG_SCHED_SMT)
  143. group = cpumask_first(topology_thread_cpumask(cpu));
  144. #else
  145. return cpu;
  146. #endif
  147. if (likely(group < NR_CPUS))
  148. return group;
  149. return cpu;
  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 or a discard request
  157. */
  158. static inline int blk_do_io_stat(struct request *rq)
  159. {
  160. return rq->rq_disk &&
  161. (rq->cmd_flags & REQ_IO_STAT) &&
  162. (rq->cmd_type == REQ_TYPE_FS ||
  163. (rq->cmd_flags & REQ_DISCARD));
  164. }
  165. #ifdef CONFIG_BLK_DEV_THROTTLING
  166. extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
  167. extern void blk_throtl_drain(struct request_queue *q);
  168. extern int blk_throtl_init(struct request_queue *q);
  169. extern void blk_throtl_exit(struct request_queue *q);
  170. extern void blk_throtl_release(struct request_queue *q);
  171. #else /* CONFIG_BLK_DEV_THROTTLING */
  172. static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
  173. {
  174. return false;
  175. }
  176. static inline void blk_throtl_drain(struct request_queue *q) { }
  177. static inline int blk_throtl_init(struct request_queue *q) { return 0; }
  178. static inline void blk_throtl_exit(struct request_queue *q) { }
  179. static inline void blk_throtl_release(struct request_queue *q) { }
  180. #endif /* CONFIG_BLK_DEV_THROTTLING */
  181. #endif /* BLK_INTERNAL_H */