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 #include "blk-mq.h" 8 9 struct io_cq; 10 struct elevator_type; 11 struct blk_mq_debugfs_attr; 12 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 23 struct blk_mq_alloc_data; 24 struct blk_mq_hw_ctx; 25 26 struct elevator_mq_ops { 27 int (*init_sched)(struct request_queue *, struct elevator_type *); 28 void (*exit_sched)(struct elevator_queue *); 29 int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int); 30 void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int); 31 void (*depth_updated)(struct blk_mq_hw_ctx *); 32 33 bool (*allow_merge)(struct request_queue *, struct request *, struct bio *); 34 bool (*bio_merge)(struct request_queue *, struct bio *, unsigned int); 35 int (*request_merge)(struct request_queue *q, struct request **, struct bio *); 36 void (*request_merged)(struct request_queue *, struct request *, enum elv_merge); 37 void (*requests_merged)(struct request_queue *, struct request *, struct request *); 38 void (*limit_depth)(blk_opf_t, struct blk_mq_alloc_data *); 39 void (*prepare_request)(struct request *); 40 void (*finish_request)(struct request *); 41 void (*insert_requests)(struct blk_mq_hw_ctx *hctx, struct list_head *list, 42 blk_insert_t flags); 43 struct request *(*dispatch_request)(struct blk_mq_hw_ctx *); 44 bool (*has_work)(struct blk_mq_hw_ctx *); 45 void (*completed_request)(struct request *, u64); 46 void (*requeue_request)(struct request *); 47 struct request *(*former_request)(struct request_queue *, struct request *); 48 struct request *(*next_request)(struct request_queue *, struct request *); 49 void (*init_icq)(struct io_cq *); 50 void (*exit_icq)(struct io_cq *); 51 }; 52 53 #define ELV_NAME_MAX (16) 54 55 struct elv_fs_entry { 56 struct attribute attr; 57 ssize_t (*show)(struct elevator_queue *, char *); 58 ssize_t (*store)(struct elevator_queue *, const char *, size_t); 59 }; 60 61 /* 62 * identifies an elevator type, such as AS or deadline 63 */ 64 struct elevator_type 65 { 66 /* managed by elevator core */ 67 struct kmem_cache *icq_cache; 68 69 /* fields provided by elevator implementation */ 70 struct elevator_mq_ops ops; 71 72 size_t icq_size; /* see iocontext.h */ 73 size_t icq_align; /* ditto */ 74 struct elv_fs_entry *elevator_attrs; 75 const char *elevator_name; 76 const char *elevator_alias; 77 struct module *elevator_owner; 78 #ifdef CONFIG_BLK_DEBUG_FS 79 const struct blk_mq_debugfs_attr *queue_debugfs_attrs; 80 const struct blk_mq_debugfs_attr *hctx_debugfs_attrs; 81 #endif 82 83 /* managed by elevator core */ 84 char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */ 85 struct list_head list; 86 }; 87 elevator_tryget(struct elevator_type * e)88 static inline bool elevator_tryget(struct elevator_type *e) 89 { 90 return try_module_get(e->elevator_owner); 91 } 92 __elevator_get(struct elevator_type * e)93 static inline void __elevator_get(struct elevator_type *e) 94 { 95 __module_get(e->elevator_owner); 96 } 97 elevator_put(struct elevator_type * e)98 static inline void elevator_put(struct elevator_type *e) 99 { 100 module_put(e->elevator_owner); 101 } 102 103 #define ELV_HASH_BITS 6 104 105 void elv_rqhash_del(struct request_queue *q, struct request *rq); 106 void elv_rqhash_add(struct request_queue *q, struct request *rq); 107 void elv_rqhash_reposition(struct request_queue *q, struct request *rq); 108 struct request *elv_rqhash_find(struct request_queue *q, sector_t offset); 109 110 /* 111 * each queue has an elevator_queue associated with it 112 */ 113 struct elevator_queue 114 { 115 struct elevator_type *type; 116 void *elevator_data; 117 struct kobject kobj; 118 struct mutex sysfs_lock; 119 unsigned long flags; 120 DECLARE_HASHTABLE(hash, ELV_HASH_BITS); 121 }; 122 123 #define ELEVATOR_FLAG_REGISTERED 0 124 #define ELEVATOR_FLAG_DISABLE_WBT 1 125 126 /* 127 * block elevator interface 128 */ 129 extern enum elv_merge elv_merge(struct request_queue *, struct request **, 130 struct bio *); 131 extern void elv_merge_requests(struct request_queue *, struct request *, 132 struct request *); 133 extern void elv_merged_request(struct request_queue *, struct request *, 134 enum elv_merge); 135 extern bool elv_attempt_insert_merge(struct request_queue *, struct request *, 136 struct list_head *); 137 extern struct request *elv_former_request(struct request_queue *, struct request *); 138 extern struct request *elv_latter_request(struct request_queue *, struct request *); 139 void elevator_init_mq(struct request_queue *q); 140 141 /* 142 * io scheduler registration 143 */ 144 extern int elv_register(struct elevator_type *); 145 extern void elv_unregister(struct elevator_type *); 146 147 /* 148 * io scheduler sysfs switching 149 */ 150 ssize_t elv_iosched_show(struct gendisk *disk, char *page); 151 int elv_iosched_load_module(struct gendisk *disk, const char *page, 152 size_t count); 153 ssize_t elv_iosched_store(struct gendisk *disk, const char *page, size_t count); 154 155 extern bool elv_bio_merge_ok(struct request *, struct bio *); 156 extern struct elevator_queue *elevator_alloc(struct request_queue *, 157 struct elevator_type *); 158 159 /* 160 * Helper functions. 161 */ 162 extern struct request *elv_rb_former_request(struct request_queue *, struct request *); 163 extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); 164 165 /* 166 * rb support functions. 167 */ 168 extern void elv_rb_add(struct rb_root *, struct request *); 169 extern void elv_rb_del(struct rb_root *, struct request *); 170 extern struct request *elv_rb_find(struct rb_root *, sector_t); 171 172 /* 173 * Insertion selection 174 */ 175 #define ELEVATOR_INSERT_FRONT 1 176 #define ELEVATOR_INSERT_BACK 2 177 #define ELEVATOR_INSERT_SORT 3 178 #define ELEVATOR_INSERT_REQUEUE 4 179 #define ELEVATOR_INSERT_FLUSH 5 180 #define ELEVATOR_INSERT_SORT_MERGE 6 181 182 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) 183 184 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) 185 #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist) 186 187 #endif /* _ELEVATOR_H */ 188