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179 lines
5.4 KiB
179 lines
5.4 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef _LINUX_ELEVATOR_H |
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#define _LINUX_ELEVATOR_H |
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#include <linux/percpu.h> |
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#include <linux/hashtable.h> |
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#ifdef CONFIG_BLOCK |
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struct io_cq; |
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struct elevator_type; |
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#ifdef CONFIG_BLK_DEBUG_FS |
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struct blk_mq_debugfs_attr; |
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#endif |
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/* |
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* Return values from elevator merger |
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*/ |
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enum elv_merge { |
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ELEVATOR_NO_MERGE = 0, |
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ELEVATOR_FRONT_MERGE = 1, |
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ELEVATOR_BACK_MERGE = 2, |
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ELEVATOR_DISCARD_MERGE = 3, |
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}; |
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struct blk_mq_alloc_data; |
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struct blk_mq_hw_ctx; |
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struct elevator_mq_ops { |
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int (*init_sched)(struct request_queue *, struct elevator_type *); |
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void (*exit_sched)(struct elevator_queue *); |
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int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int); |
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void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int); |
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void (*depth_updated)(struct blk_mq_hw_ctx *); |
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bool (*allow_merge)(struct request_queue *, struct request *, struct bio *); |
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bool (*bio_merge)(struct request_queue *, struct bio *, unsigned int); |
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int (*request_merge)(struct request_queue *q, struct request **, struct bio *); |
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void (*request_merged)(struct request_queue *, struct request *, enum elv_merge); |
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void (*requests_merged)(struct request_queue *, struct request *, struct request *); |
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void (*limit_depth)(unsigned int, struct blk_mq_alloc_data *); |
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void (*prepare_request)(struct request *); |
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void (*finish_request)(struct request *); |
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void (*insert_requests)(struct blk_mq_hw_ctx *, struct list_head *, bool); |
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struct request *(*dispatch_request)(struct blk_mq_hw_ctx *); |
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bool (*has_work)(struct blk_mq_hw_ctx *); |
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void (*completed_request)(struct request *, u64); |
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void (*requeue_request)(struct request *); |
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struct request *(*former_request)(struct request_queue *, struct request *); |
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struct request *(*next_request)(struct request_queue *, struct request *); |
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void (*init_icq)(struct io_cq *); |
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void (*exit_icq)(struct io_cq *); |
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}; |
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#define ELV_NAME_MAX (16) |
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struct elv_fs_entry { |
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struct attribute attr; |
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ssize_t (*show)(struct elevator_queue *, char *); |
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ssize_t (*store)(struct elevator_queue *, const char *, size_t); |
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}; |
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/* |
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* identifies an elevator type, such as AS or deadline |
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*/ |
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struct elevator_type |
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{ |
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/* managed by elevator core */ |
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struct kmem_cache *icq_cache; |
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/* fields provided by elevator implementation */ |
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struct elevator_mq_ops ops; |
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size_t icq_size; /* see iocontext.h */ |
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size_t icq_align; /* ditto */ |
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struct elv_fs_entry *elevator_attrs; |
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const char *elevator_name; |
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const char *elevator_alias; |
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const unsigned int elevator_features; |
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struct module *elevator_owner; |
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#ifdef CONFIG_BLK_DEBUG_FS |
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const struct blk_mq_debugfs_attr *queue_debugfs_attrs; |
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const struct blk_mq_debugfs_attr *hctx_debugfs_attrs; |
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#endif |
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/* managed by elevator core */ |
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char icq_cache_name[ELV_NAME_MAX + 6]; /* elvname + "_io_cq" */ |
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struct list_head list; |
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}; |
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#define ELV_HASH_BITS 6 |
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void elv_rqhash_del(struct request_queue *q, struct request *rq); |
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void elv_rqhash_add(struct request_queue *q, struct request *rq); |
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void elv_rqhash_reposition(struct request_queue *q, struct request *rq); |
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struct request *elv_rqhash_find(struct request_queue *q, sector_t offset); |
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/* |
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* each queue has an elevator_queue associated with it |
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*/ |
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struct elevator_queue |
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{ |
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struct elevator_type *type; |
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void *elevator_data; |
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struct kobject kobj; |
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struct mutex sysfs_lock; |
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unsigned int registered:1; |
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DECLARE_HASHTABLE(hash, ELV_HASH_BITS); |
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}; |
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/* |
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* block elevator interface |
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*/ |
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extern enum elv_merge elv_merge(struct request_queue *, struct request **, |
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struct bio *); |
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extern void elv_merge_requests(struct request_queue *, struct request *, |
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struct request *); |
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extern void elv_merged_request(struct request_queue *, struct request *, |
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enum elv_merge); |
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extern bool elv_attempt_insert_merge(struct request_queue *, struct request *); |
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extern struct request *elv_former_request(struct request_queue *, struct request *); |
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extern struct request *elv_latter_request(struct request_queue *, struct request *); |
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/* |
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* io scheduler registration |
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*/ |
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extern int elv_register(struct elevator_type *); |
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extern void elv_unregister(struct elevator_type *); |
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/* |
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* io scheduler sysfs switching |
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*/ |
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extern ssize_t elv_iosched_show(struct request_queue *, char *); |
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extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); |
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extern bool elv_bio_merge_ok(struct request *, struct bio *); |
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extern struct elevator_queue *elevator_alloc(struct request_queue *, |
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struct elevator_type *); |
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/* |
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* Helper functions. |
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*/ |
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extern struct request *elv_rb_former_request(struct request_queue *, struct request *); |
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extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); |
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/* |
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* rb support functions. |
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*/ |
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extern void elv_rb_add(struct rb_root *, struct request *); |
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extern void elv_rb_del(struct rb_root *, struct request *); |
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extern struct request *elv_rb_find(struct rb_root *, sector_t); |
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/* |
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* Insertion selection |
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*/ |
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#define ELEVATOR_INSERT_FRONT 1 |
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#define ELEVATOR_INSERT_BACK 2 |
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#define ELEVATOR_INSERT_SORT 3 |
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#define ELEVATOR_INSERT_REQUEUE 4 |
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#define ELEVATOR_INSERT_FLUSH 5 |
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#define ELEVATOR_INSERT_SORT_MERGE 6 |
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#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) |
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#define rb_entry_rq(node) rb_entry((node), struct request, rb_node) |
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#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
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#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist) |
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/* |
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* Elevator features. |
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*/ |
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/* Supports zoned block devices sequential write constraint */ |
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#define ELEVATOR_F_ZBD_SEQ_WRITE (1U << 0) |
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/* Supports scheduling on multiple hardware queues */ |
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#define ELEVATOR_F_MQ_AWARE (1U << 1) |
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#endif /* CONFIG_BLOCK */ |
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#endif
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