1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ELEVATOR_H 3 #define _ELEVATOR_H 4 5 #include <linux/percpu.h> 6 #include <linux/hashtable.h> 7 8 struct io_cq; 9 struct elevator_type; 10 struct blk_mq_debugfs_attr; 11 12 /* 13 * Return values from elevator merger 14 */ 15 enum elv_merge { 16 ELEVATOR_NO_MERGE = 0, 17 ELEVATOR_FRONT_MERGE = 1, 18 ELEVATOR_BACK_MERGE = 2, 19 ELEVATOR_DISCARD_MERGE = 3, 20 }; 21 22 struct blk_mq_alloc_data; 23 struct blk_mq_hw_ctx; 24 25 struct elevator_mq_ops { 26 int (*init_sched)(struct request_queue *, struct elevator_type *); 27 void (*exit_sched)(struct elevator_queue *); 28 int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int); 29 void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int); 30 void (*depth_updated)(struct blk_mq_hw_ctx *); 31 32 bool (*allow_merge)(struct request_queue *, struct request *, struct bio *); 33 bool (*bio_merge)(struct request_queue *, struct bio *, unsigned int); 34 int (*request_merge)(struct request_queue *q, struct request **, struct bio *); 35 void (*request_merged)(struct request_queue *, struct request *, enum elv_merge); 36 void (*requests_merged)(struct request_queue *, struct request *, struct request *); 37 void (*limit_depth)(blk_opf_t, struct blk_mq_alloc_data *); 38 void (*prepare_request)(struct request *); 39 void (*finish_request)(struct request *); 40 void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool); 41 struct request *(*dispatch_request)(struct blk_mq_hw_ctx *); 42 bool (*has_work)(struct blk_mq_hw_ctx *); 43 void (*completed_request)(struct request *, u64); 44 void (*requeue_request)(struct request *); 45 struct request *(*former_request)(struct request_queue *, struct request *); 46 struct request *(*next_request)(struct request_queue *, struct request *); 47 void (*init_icq)(struct io_cq *); 48 void (*exit_icq)(struct io_cq *); 49 }; 50 51 #define ELV_NAME_MAX (16) 52 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 /* 60 * identifies an elevator type, such as AS or deadline 61 */ 62 struct elevator_type 63 { 64 /* managed by elevator core */ 65 struct kmem_cache *icq_cache; 66 67 /* fields provided by elevator implementation */ 68 struct elevator_mq_ops ops; 69 70 size_t icq_size; /* see iocontext.h */ 71 size_t icq_align; /* ditto */ 72 struct elv_fs_entry *elevator_attrs; 73 const char *elevator_name; 74 const char *elevator_alias; 75 const unsigned int elevator_features; 76 struct module *elevator_owner; 77 #ifdef CONFIG_BLK_DEBUG_FS 78 const struct blk_mq_debugfs_attr *queue_debugfs_attrs; 79 const struct blk_mq_debugfs_attr *hctx_debugfs_attrs; 80 #endif 81 82 /* managed by elevator core */ 83 char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */ 84 struct list_head list; 85 }; 86 87 #define ELV_HASH_BITS 6 88 89 void elv_rqhash_del(struct request_queue *q, struct request *rq); 90 void elv_rqhash_add(struct request_queue *q, struct request *rq); 91 void elv_rqhash_reposition(struct request_queue *q, struct request *rq); 92 struct request *elv_rqhash_find(struct request_queue *q, sector_t offset); 93 94 /* 95 * each queue has an elevator_queue associated with it 96 */ 97 struct elevator_queue 98 { 99 struct elevator_type *type; 100 void *elevator_data; 101 struct kobject kobj; 102 struct mutex sysfs_lock; 103 unsigned int registered:1; 104 DECLARE_HASHTABLE(hash, ELV_HASH_BITS); 105 }; 106 107 /* 108 * block elevator interface 109 */ 110 extern enum elv_merge elv_merge(struct request_queue *, struct request **, 111 struct bio *); 112 extern void elv_merge_requests(struct request_queue *, struct request *, 113 struct request *); 114 extern void elv_merged_request(struct request_queue *, struct request *, 115 enum elv_merge); 116 extern bool elv_attempt_insert_merge(struct request_queue *, struct request *, 117 struct list_head *); 118 extern struct request *elv_former_request(struct request_queue *, struct request *); 119 extern struct request *elv_latter_request(struct request_queue *, struct request *); 120 void elevator_init_mq(struct request_queue *q); 121 122 /* 123 * io scheduler registration 124 */ 125 extern int elv_register(struct elevator_type *); 126 extern void elv_unregister(struct elevator_type *); 127 128 /* 129 * io scheduler sysfs switching 130 */ 131 extern ssize_t elv_iosched_show(struct request_queue *, char *); 132 extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); 133 134 extern bool elv_bio_merge_ok(struct request *, struct bio *); 135 extern struct elevator_queue *elevator_alloc(struct request_queue *, 136 struct elevator_type *); 137 138 /* 139 * Helper functions. 140 */ 141 extern struct request *elv_rb_former_request(struct request_queue *, struct request *); 142 extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); 143 144 /* 145 * rb support functions. 146 */ 147 extern void elv_rb_add(struct rb_root *, struct request *); 148 extern void elv_rb_del(struct rb_root *, struct request *); 149 extern struct request *elv_rb_find(struct rb_root *, sector_t); 150 151 /* 152 * Insertion selection 153 */ 154 #define ELEVATOR_INSERT_FRONT 1 155 #define ELEVATOR_INSERT_BACK 2 156 #define ELEVATOR_INSERT_SORT 3 157 #define ELEVATOR_INSERT_REQUEUE 4 158 #define ELEVATOR_INSERT_FLUSH 5 159 #define ELEVATOR_INSERT_SORT_MERGE 6 160 161 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) 162 163 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) 164 #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist) 165 166 #endif /* _ELEVATOR_H */ 167