#ifndef _LINUX_ELEVATOR_H #define _LINUX_ELEVATOR_H #include <linux/percpu.h> #ifdef CONFIG_BLOCK typedef int (elevator_merge_fn) (struct request_queue *, struct request **, struct bio *); typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *); typedef int (elevator_dispatch_fn) (struct request_queue *, int); typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); typedef int (elevator_queue_empty_fn) (struct request_queue *); typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *); typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *); typedef int (elevator_may_queue_fn) (struct request_queue *, int); typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t); typedef void (elevator_put_req_fn) (struct request *); typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); typedef void *(elevator_init_fn) (struct request_queue *); typedef void (elevator_exit_fn) (elevator_t *); struct elevator_ops { elevator_merge_fn *elevator_merge_fn; elevator_merged_fn *elevator_merged_fn; elevator_merge_req_fn *elevator_merge_req_fn; elevator_allow_merge_fn *elevator_allow_merge_fn; elevator_dispatch_fn *elevator_dispatch_fn; elevator_add_req_fn *elevator_add_req_fn; elevator_activate_req_fn *elevator_activate_req_fn; elevator_deactivate_req_fn *elevator_deactivate_req_fn; elevator_queue_empty_fn *elevator_queue_empty_fn; elevator_completed_req_fn *elevator_completed_req_fn; elevator_request_list_fn *elevator_former_req_fn; elevator_request_list_fn *elevator_latter_req_fn; elevator_set_req_fn *elevator_set_req_fn; elevator_put_req_fn *elevator_put_req_fn; elevator_may_queue_fn *elevator_may_queue_fn; elevator_init_fn *elevator_init_fn; elevator_exit_fn *elevator_exit_fn; void (*trim)(struct io_context *); }; #define ELV_NAME_MAX (16) struct elv_fs_entry { struct attribute attr; ssize_t (*show)(elevator_t *, char *); ssize_t (*store)(elevator_t *, const char *, size_t); }; /* * identifies an elevator type, such as AS or deadline */ struct elevator_type { struct list_head list; struct elevator_ops ops; struct elv_fs_entry *elevator_attrs; char elevator_name[ELV_NAME_MAX]; struct module *elevator_owner; }; /* * each queue has an elevator_queue associated with it */ struct elevator_queue { struct elevator_ops *ops; void *elevator_data; struct kobject kobj; struct elevator_type *elevator_type; struct mutex sysfs_lock; struct hlist_head *hash; }; /* * block elevator interface */ extern void elv_dispatch_sort(struct request_queue *, struct request *); extern void elv_dispatch_add_tail(struct request_queue *, struct request *); extern void elv_add_request(struct request_queue *, struct request *, int, int); extern void __elv_add_request(struct request_queue *, struct request *, int, int); extern void elv_insert(struct request_queue *, struct request *, int); extern int elv_merge(struct request_queue *, struct request **, struct bio *); extern void elv_merge_requests(struct request_queue *, struct request *, struct request *); extern void elv_merged_request(struct request_queue *, struct request *, int); extern void elv_dequeue_request(struct request_queue *, struct request *); extern void elv_requeue_request(struct request_queue *, struct request *); extern int elv_queue_empty(struct request_queue *); extern struct request *elv_next_request(struct request_queue *q); extern struct request *elv_former_request(struct request_queue *, struct request *); extern struct request *elv_latter_request(struct request_queue *, struct request *); extern int elv_register_queue(struct request_queue *q); extern void elv_unregister_queue(struct request_queue *q); extern int elv_may_queue(struct request_queue *, int); extern void elv_completed_request(struct request_queue *, struct request *); extern int elv_set_request(struct request_queue *, struct request *, gfp_t); extern void elv_put_request(struct request_queue *, struct request *); /* * io scheduler registration */ extern int elv_register(struct elevator_type *); extern void elv_unregister(struct elevator_type *); /* * io scheduler sysfs switching */ extern ssize_t elv_iosched_show(struct request_queue *, char *); extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); extern int elevator_init(struct request_queue *, char *); extern void elevator_exit(elevator_t *); extern int elv_rq_merge_ok(struct request *, struct bio *); /* * Helper functions. */ extern struct request *elv_rb_former_request(struct request_queue *, struct request *); extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); /* * rb support functions. */ extern struct request *elv_rb_add(struct rb_root *, struct request *); extern void elv_rb_del(struct rb_root *, struct request *); extern struct request *elv_rb_find(struct rb_root *, sector_t); /* * Return values from elevator merger */ #define ELEVATOR_NO_MERGE 0 #define ELEVATOR_FRONT_MERGE 1 #define ELEVATOR_BACK_MERGE 2 /* * Insertion selection */ #define ELEVATOR_INSERT_FRONT 1 #define ELEVATOR_INSERT_BACK 2 #define ELEVATOR_INSERT_SORT 3 #define ELEVATOR_INSERT_REQUEUE 4 /* * return values from elevator_may_queue_fn */ enum { ELV_MQUEUE_MAY, ELV_MQUEUE_NO, ELV_MQUEUE_MUST, }; #define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors) #define rb_entry_rq(node) rb_entry((node), struct request, rb_node) /* * Hack to reuse the donelist list_head as the fifo time holder while * the request is in the io scheduler. Saves an unsigned long in rq. */ #define rq_fifo_time(rq) ((unsigned long) (rq)->donelist.next) #define rq_set_fifo_time(rq,exp) ((rq)->donelist.next = (void *) (exp)) #define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) #define rq_fifo_clear(rq) do { \ list_del_init(&(rq)->queuelist); \ INIT_LIST_HEAD(&(rq)->donelist); \ } while (0) /* * io context count accounting */ #define elv_ioc_count_mod(name, __val) \ do { \ preempt_disable(); \ __get_cpu_var(name) += (__val); \ preempt_enable(); \ } while (0) #define elv_ioc_count_inc(name) elv_ioc_count_mod(name, 1) #define elv_ioc_count_dec(name) elv_ioc_count_mod(name, -1) #define elv_ioc_count_read(name) \ ({ \ unsigned long __val = 0; \ int __cpu; \ smp_wmb(); \ for_each_possible_cpu(__cpu) \ __val += per_cpu(name, __cpu); \ __val; \ }) #endif /* CONFIG_BLOCK */ #endif