1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_ELEVATOR_H 3 #define _LINUX_ELEVATOR_H 4 5 #include <linux/percpu.h> 6 #include <linux/hashtable.h> 7 #include <linux/android_kabi.h> 8 9 #ifdef CONFIG_BLOCK 10 11 struct io_cq; 12 struct elevator_type; 13 #ifdef CONFIG_BLK_DEBUG_FS 14 struct blk_mq_debugfs_attr; 15 #endif 16 17 /* 18 * Return values from elevator merger 19 */ 20 enum elv_merge { 21 ELEVATOR_NO_MERGE = 0, 22 ELEVATOR_FRONT_MERGE = 1, 23 ELEVATOR_BACK_MERGE = 2, 24 ELEVATOR_DISCARD_MERGE = 3, 25 }; 26 27 struct blk_mq_alloc_data; 28 struct blk_mq_hw_ctx; 29 30 struct elevator_mq_ops { 31 int (*init_sched)(struct request_queue *, struct elevator_type *); 32 void (*exit_sched)(struct elevator_queue *); 33 int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int); 34 void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int); 35 void (*depth_updated)(struct blk_mq_hw_ctx *); 36 37 bool (*allow_merge)(struct request_queue *, struct request *, struct bio *); 38 /* 39 * CRC "preservation" hack 40 * 41 * This is due to efed9a3337e3 ("kyber: fix out of bounds access when * preempted") 42 * showing up in 5.4.120. It does not actually change anything relevant, but 43 * the CRC check goes crazy because of it, so paper over it by keeping the old 44 * signature for when we do the check. 45 */ 46 #ifdef __GENKSYMS__ 47 bool (*bio_merge)(struct blk_mq_hw_ctx *, struct bio *, unsigned int); 48 #else 49 bool (*bio_merge)(struct request_queue *, struct bio *, unsigned int); 50 #endif 51 int (*request_merge)(struct request_queue *q, struct request **, struct bio *); 52 void (*request_merged)(struct request_queue *, struct request *, enum elv_merge); 53 void (*requests_merged)(struct request_queue *, struct request *, struct request *); 54 void (*limit_depth)(unsigned int, struct blk_mq_alloc_data *); 55 void (*prepare_request)(struct request *, struct bio *bio); 56 void (*finish_request)(struct request *); 57 void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool); 58 struct request *(*dispatch_request)(struct blk_mq_hw_ctx *); 59 bool (*has_work)(struct blk_mq_hw_ctx *); 60 void (*completed_request)(struct request *, u64); 61 void (*requeue_request)(struct request *); 62 struct request *(*former_request)(struct request_queue *, struct request *); 63 struct request *(*next_request)(struct request_queue *, struct request *); 64 void (*init_icq)(struct io_cq *); 65 void (*exit_icq)(struct io_cq *); 66 67 ANDROID_KABI_RESERVE(1); 68 ANDROID_KABI_RESERVE(2); 69 ANDROID_KABI_RESERVE(3); 70 ANDROID_KABI_RESERVE(4); 71 }; 72 73 #define ELV_NAME_MAX (16) 74 75 struct elv_fs_entry { 76 struct attribute attr; 77 ssize_t (*show)(struct elevator_queue *, char *); 78 ssize_t (*store)(struct elevator_queue *, const char *, size_t); 79 }; 80 81 /* 82 * identifies an elevator type, such as AS or deadline 83 */ 84 struct elevator_type 85 { 86 /* managed by elevator core */ 87 struct kmem_cache *icq_cache; 88 89 /* fields provided by elevator implementation */ 90 struct elevator_mq_ops ops; 91 92 size_t icq_size; /* see iocontext.h */ 93 size_t icq_align; /* ditto */ 94 struct elv_fs_entry *elevator_attrs; 95 const char *elevator_name; 96 const char *elevator_alias; 97 const unsigned int elevator_features; 98 struct module *elevator_owner; 99 #ifdef CONFIG_BLK_DEBUG_FS 100 const struct blk_mq_debugfs_attr *queue_debugfs_attrs; 101 const struct blk_mq_debugfs_attr *hctx_debugfs_attrs; 102 #endif 103 104 /* managed by elevator core */ 105 char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */ 106 struct list_head list; 107 108 ANDROID_KABI_RESERVE(1); 109 ANDROID_KABI_RESERVE(2); 110 }; 111 112 #define ELV_HASH_BITS 6 113 114 void elv_rqhash_del(struct request_queue *q, struct request *rq); 115 void elv_rqhash_add(struct request_queue *q, struct request *rq); 116 void elv_rqhash_reposition(struct request_queue *q, struct request *rq); 117 struct request *elv_rqhash_find(struct request_queue *q, sector_t offset); 118 119 /* 120 * each queue has an elevator_queue associated with it 121 */ 122 struct elevator_queue 123 { 124 struct elevator_type *type; 125 void *elevator_data; 126 struct kobject kobj; 127 struct mutex sysfs_lock; 128 unsigned int registered:1; 129 DECLARE_HASHTABLE(hash, ELV_HASH_BITS); 130 }; 131 132 /* 133 * block elevator interface 134 */ 135 extern enum elv_merge elv_merge(struct request_queue *, struct request **, 136 struct bio *); 137 extern void elv_merge_requests(struct request_queue *, struct request *, 138 struct request *); 139 extern void elv_merged_request(struct request_queue *, struct request *, 140 enum elv_merge); 141 extern bool elv_attempt_insert_merge(struct request_queue *, struct request *); 142 extern struct request *elv_former_request(struct request_queue *, struct request *); 143 extern struct request *elv_latter_request(struct request_queue *, struct request *); 144 145 /* 146 * io scheduler registration 147 */ 148 extern int elv_register(struct elevator_type *); 149 extern void elv_unregister(struct elevator_type *); 150 151 /* 152 * io scheduler sysfs switching 153 */ 154 extern ssize_t elv_iosched_show(struct request_queue *, char *); 155 extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); 156 157 extern bool elv_bio_merge_ok(struct request *, struct bio *); 158 extern struct elevator_queue *elevator_alloc(struct request_queue *, 159 struct elevator_type *); 160 161 /* 162 * Helper functions. 163 */ 164 extern struct request *elv_rb_former_request(struct request_queue *, struct request *); 165 extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); 166 167 /* 168 * rb support functions. 169 */ 170 extern void elv_rb_add(struct rb_root *, struct request *); 171 extern void elv_rb_del(struct rb_root *, struct request *); 172 extern struct request *elv_rb_find(struct rb_root *, sector_t); 173 174 /* 175 * Insertion selection 176 */ 177 #define ELEVATOR_INSERT_FRONT 1 178 #define ELEVATOR_INSERT_BACK 2 179 #define ELEVATOR_INSERT_SORT 3 180 #define ELEVATOR_INSERT_REQUEUE 4 181 #define ELEVATOR_INSERT_FLUSH 5 182 #define ELEVATOR_INSERT_SORT_MERGE 6 183 184 #define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) 185 #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) 186 187 #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) 188 #define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist) 189 190 /* 191 * Elevator features. 192 */ 193 194 /* Supports zoned block devices sequential write constraint */ 195 #define ELEVATOR_F_ZBD_SEQ_WRITE (1U << 0) 196 197 #endif /* CONFIG_BLOCK */ 198 #endif 199