elevator.h 5.6 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #ifndef _LINUX_ELEVATOR_H
  3. #define _LINUX_ELEVATOR_H
  4. #include <linux/percpu.h>
  5. #include <linux/hashtable.h>
  6. #include <linux/android_kabi.h>
  7. #ifdef CONFIG_BLOCK
  8. struct io_cq;
  9. struct elevator_type;
  10. #ifdef CONFIG_BLK_DEBUG_FS
  11. struct blk_mq_debugfs_attr;
  12. #endif
  13. /*
  14. * Return values from elevator merger
  15. */
  16. enum elv_merge {
  17. ELEVATOR_NO_MERGE = 0,
  18. ELEVATOR_FRONT_MERGE = 1,
  19. ELEVATOR_BACK_MERGE = 2,
  20. ELEVATOR_DISCARD_MERGE = 3,
  21. };
  22. struct blk_mq_alloc_data;
  23. struct blk_mq_hw_ctx;
  24. struct elevator_mq_ops {
  25. int (*init_sched)(struct request_queue *, struct elevator_type *);
  26. void (*exit_sched)(struct elevator_queue *);
  27. int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int);
  28. void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int);
  29. void (*depth_updated)(struct blk_mq_hw_ctx *);
  30. bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);
  31. bool (*bio_merge)(struct request_queue *, struct bio *, unsigned int);
  32. int (*request_merge)(struct request_queue *q, struct request **, struct bio *);
  33. void (*request_merged)(struct request_queue *, struct request *, enum elv_merge);
  34. void (*requests_merged)(struct request_queue *, struct request *, struct request *);
  35. void (*limit_depth)(unsigned int, struct blk_mq_alloc_data *);
  36. void (*prepare_request)(struct request *);
  37. void (*finish_request)(struct request *);
  38. void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool);
  39. struct request *(*dispatch_request)(struct blk_mq_hw_ctx *);
  40. bool (*has_work)(struct blk_mq_hw_ctx *);
  41. void (*completed_request)(struct request *, u64);
  42. void (*requeue_request)(struct request *);
  43. struct request *(*former_request)(struct request_queue *, struct request *);
  44. struct request *(*next_request)(struct request_queue *, struct request *);
  45. void (*init_icq)(struct io_cq *);
  46. void (*exit_icq)(struct io_cq *);
  47. ANDROID_KABI_RESERVE(1);
  48. ANDROID_KABI_RESERVE(2);
  49. ANDROID_KABI_RESERVE(3);
  50. ANDROID_KABI_RESERVE(4);
  51. };
  52. #define ELV_NAME_MAX (16)
  53. struct elv_fs_entry {
  54. struct attribute attr;
  55. ssize_t (*show)(struct elevator_queue *, char *);
  56. ssize_t (*store)(struct elevator_queue *, const char *, size_t);
  57. };
  58. /*
  59. * identifies an elevator type, such as AS or deadline
  60. */
  61. struct elevator_type
  62. {
  63. /* managed by elevator core */
  64. struct kmem_cache *icq_cache;
  65. /* fields provided by elevator implementation */
  66. struct elevator_mq_ops ops;
  67. size_t icq_size; /* see iocontext.h */
  68. size_t icq_align; /* ditto */
  69. struct elv_fs_entry *elevator_attrs;
  70. const char *elevator_name;
  71. const char *elevator_alias;
  72. const unsigned int elevator_features;
  73. struct module *elevator_owner;
  74. #ifdef CONFIG_BLK_DEBUG_FS
  75. const struct blk_mq_debugfs_attr *queue_debugfs_attrs;
  76. const struct blk_mq_debugfs_attr *hctx_debugfs_attrs;
  77. #endif
  78. /* managed by elevator core */
  79. char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */
  80. struct list_head list;
  81. ANDROID_KABI_RESERVE(1);
  82. ANDROID_KABI_RESERVE(2);
  83. };
  84. #define ELV_HASH_BITS 6
  85. void elv_rqhash_del(struct request_queue *q, struct request *rq);
  86. void elv_rqhash_add(struct request_queue *q, struct request *rq);
  87. void elv_rqhash_reposition(struct request_queue *q, struct request *rq);
  88. struct request *elv_rqhash_find(struct request_queue *q, sector_t offset);
  89. /*
  90. * each queue has an elevator_queue associated with it
  91. */
  92. struct elevator_queue
  93. {
  94. struct elevator_type *type;
  95. void *elevator_data;
  96. struct kobject kobj;
  97. struct mutex sysfs_lock;
  98. unsigned int registered:1;
  99. DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
  100. };
  101. /*
  102. * block elevator interface
  103. */
  104. extern enum elv_merge elv_merge(struct request_queue *, struct request **,
  105. struct bio *);
  106. extern void elv_merge_requests(struct request_queue *, struct request *,
  107. struct request *);
  108. extern void elv_merged_request(struct request_queue *, struct request *,
  109. enum elv_merge);
  110. extern bool elv_attempt_insert_merge(struct request_queue *, struct request *);
  111. extern struct request *elv_former_request(struct request_queue *, struct request *);
  112. extern struct request *elv_latter_request(struct request_queue *, struct request *);
  113. /*
  114. * io scheduler registration
  115. */
  116. extern int elv_register(struct elevator_type *);
  117. extern void elv_unregister(struct elevator_type *);
  118. /*
  119. * io scheduler sysfs switching
  120. */
  121. extern ssize_t elv_iosched_show(struct request_queue *, char *);
  122. extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
  123. extern bool elv_bio_merge_ok(struct request *, struct bio *);
  124. extern struct elevator_queue *elevator_alloc(struct request_queue *,
  125. struct elevator_type *);
  126. /*
  127. * Helper functions.
  128. */
  129. extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
  130. extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
  131. /*
  132. * rb support functions.
  133. */
  134. extern void elv_rb_add(struct rb_root *, struct request *);
  135. extern void elv_rb_del(struct rb_root *, struct request *);
  136. extern struct request *elv_rb_find(struct rb_root *, sector_t);
  137. /*
  138. * Insertion selection
  139. */
  140. #define ELEVATOR_INSERT_FRONT 1
  141. #define ELEVATOR_INSERT_BACK 2
  142. #define ELEVATOR_INSERT_SORT 3
  143. #define ELEVATOR_INSERT_REQUEUE 4
  144. #define ELEVATOR_INSERT_FLUSH 5
  145. #define ELEVATOR_INSERT_SORT_MERGE 6
  146. #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
  147. #define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
  148. #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
  149. #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
  150. /*
  151. * Elevator features.
  152. */
  153. /* Supports zoned block devices sequential write constraint */
  154. #define ELEVATOR_F_ZBD_SEQ_WRITE (1U << 0)
  155. /* Supports scheduling on multiple hardware queues */
  156. #define ELEVATOR_F_MQ_AWARE (1U << 1)
  157. #endif /* CONFIG_BLOCK */
  158. #endif