2005-04-17 05:20:36 +07:00
|
|
|
#ifndef _LINUX_ELEVATOR_H
|
|
|
|
#define _LINUX_ELEVATOR_H
|
|
|
|
|
2006-07-22 20:37:43 +07:00
|
|
|
#include <linux/percpu.h>
|
|
|
|
|
[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-10-01 01:45:40 +07:00
|
|
|
#ifdef CONFIG_BLOCK
|
|
|
|
|
2007-07-24 14:28:11 +07:00
|
|
|
typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
|
2005-04-17 05:20:36 +07:00
|
|
|
struct bio *);
|
|
|
|
|
2007-07-24 14:28:11 +07:00
|
|
|
typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2007-07-24 14:28:11 +07:00
|
|
|
typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2007-07-24 14:28:11 +07:00
|
|
|
typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *);
|
2006-12-20 17:04:12 +07:00
|
|
|
|
2007-07-24 14:28:11 +07:00
|
|
|
typedef int (elevator_dispatch_fn) (struct request_queue *, int);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2007-07-24 14:28:11 +07:00
|
|
|
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);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2007-07-24 14:28:11 +07:00
|
|
|
typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t);
|
2006-12-01 16:42:33 +07:00
|
|
|
typedef void (elevator_put_req_fn) (struct request *);
|
2007-07-24 14:28:11 +07:00
|
|
|
typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
|
|
|
|
typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2007-07-24 14:28:11 +07:00
|
|
|
typedef void *(elevator_init_fn) (struct request_queue *);
|
2005-04-17 05:20:36 +07:00
|
|
|
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;
|
2006-12-20 17:04:12 +07:00
|
|
|
elevator_allow_merge_fn *elevator_allow_merge_fn;
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2005-10-20 21:23:44 +07:00
|
|
|
elevator_dispatch_fn *elevator_dispatch_fn;
|
2005-04-17 05:20:36 +07:00
|
|
|
elevator_add_req_fn *elevator_add_req_fn;
|
2005-10-20 21:23:44 +07:00
|
|
|
elevator_activate_req_fn *elevator_activate_req_fn;
|
2005-04-17 05:20:36 +07:00
|
|
|
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;
|
2006-03-19 01:21:20 +07:00
|
|
|
void (*trim)(struct io_context *);
|
2005-04-17 05:20:36 +07:00
|
|
|
};
|
|
|
|
|
|
|
|
#define ELV_NAME_MAX (16)
|
|
|
|
|
2006-03-19 10:27:18 +07:00
|
|
|
struct elv_fs_entry {
|
|
|
|
struct attribute attr;
|
|
|
|
ssize_t (*show)(elevator_t *, char *);
|
|
|
|
ssize_t (*store)(elevator_t *, const char *, size_t);
|
|
|
|
};
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
/*
|
|
|
|
* identifies an elevator type, such as AS or deadline
|
|
|
|
*/
|
|
|
|
struct elevator_type
|
|
|
|
{
|
|
|
|
struct list_head list;
|
|
|
|
struct elevator_ops ops;
|
2006-03-19 10:27:18 +07:00
|
|
|
struct elv_fs_entry *elevator_attrs;
|
2005-04-17 05:20:36 +07:00
|
|
|
char elevator_name[ELV_NAME_MAX];
|
|
|
|
struct module *elevator_owner;
|
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
2006-01-10 06:09:36 +07:00
|
|
|
* each queue has an elevator_queue associated with it
|
2005-04-17 05:20:36 +07:00
|
|
|
*/
|
|
|
|
struct elevator_queue
|
|
|
|
{
|
|
|
|
struct elevator_ops *ops;
|
|
|
|
void *elevator_data;
|
|
|
|
struct kobject kobj;
|
|
|
|
struct elevator_type *elevator_type;
|
2006-03-19 06:35:43 +07:00
|
|
|
struct mutex sysfs_lock;
|
2006-07-28 14:23:08 +07:00
|
|
|
struct hlist_head *hash;
|
2005-04-17 05:20:36 +07:00
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* block elevator interface
|
|
|
|
*/
|
2007-07-24 14:28:11 +07:00
|
|
|
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 *,
|
2005-04-17 05:20:36 +07:00
|
|
|
struct request *);
|
2007-07-24 14:28:11 +07:00
|
|
|
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 *);
|
2005-04-17 05:20:36 +07:00
|
|
|
extern struct request *elv_next_request(struct request_queue *q);
|
2007-07-24 14:28:11 +07:00
|
|
|
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);
|
2008-09-14 01:31:27 +07:00
|
|
|
extern void elv_abort_queue(struct request_queue *);
|
2007-07-24 14:28:11 +07:00
|
|
|
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 *);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
|
|
|
/*
|
|
|
|
* io scheduler registration
|
|
|
|
*/
|
2007-12-13 00:51:56 +07:00
|
|
|
extern void elv_register(struct elevator_type *);
|
2005-04-17 05:20:36 +07:00
|
|
|
extern void elv_unregister(struct elevator_type *);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* io scheduler sysfs switching
|
|
|
|
*/
|
2007-07-24 14:28:11 +07:00
|
|
|
extern ssize_t elv_iosched_show(struct request_queue *, char *);
|
|
|
|
extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2007-07-24 14:28:11 +07:00
|
|
|
extern int elevator_init(struct request_queue *, char *);
|
2005-04-17 05:20:36 +07:00
|
|
|
extern void elevator_exit(elevator_t *);
|
|
|
|
extern int elv_rq_merge_ok(struct request *, struct bio *);
|
|
|
|
|
2006-07-13 16:55:04 +07:00
|
|
|
/*
|
|
|
|
* Helper functions.
|
|
|
|
*/
|
2007-07-24 14:28:11 +07:00
|
|
|
extern struct request *elv_rb_former_request(struct request_queue *, struct request *);
|
|
|
|
extern struct request *elv_rb_latter_request(struct request_queue *, struct request *);
|
2006-07-13 16:55:04 +07:00
|
|
|
|
|
|
|
/*
|
|
|
|
* 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);
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
/*
|
|
|
|
* 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
|
2006-01-06 15:51:03 +07:00
|
|
|
#define ELEVATOR_INSERT_REQUEUE 4
|
2005-04-17 05:20:36 +07:00
|
|
|
|
|
|
|
/*
|
|
|
|
* return values from elevator_may_queue_fn
|
|
|
|
*/
|
|
|
|
enum {
|
|
|
|
ELV_MQUEUE_MAY,
|
|
|
|
ELV_MQUEUE_NO,
|
|
|
|
ELV_MQUEUE_MUST,
|
|
|
|
};
|
|
|
|
|
2005-10-20 21:37:00 +07:00
|
|
|
#define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
|
2006-07-13 16:55:04 +07:00
|
|
|
#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
|
2005-10-20 21:37:00 +07:00
|
|
|
|
2006-07-12 02:49:15 +07:00
|
|
|
/*
|
2008-09-14 01:26:01 +07:00
|
|
|
* Hack to reuse the csd.list list_head as the fifo time holder while
|
2006-07-12 02:49:15 +07:00
|
|
|
* the request is in the io scheduler. Saves an unsigned long in rq.
|
|
|
|
*/
|
2008-09-14 01:26:01 +07:00
|
|
|
#define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
|
|
|
|
#define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
|
2006-07-12 02:49:15 +07:00
|
|
|
#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
|
|
|
|
#define rq_fifo_clear(rq) do { \
|
|
|
|
list_del_init(&(rq)->queuelist); \
|
2008-09-14 01:26:01 +07:00
|
|
|
INIT_LIST_HEAD(&(rq)->csd.list); \
|
2006-07-12 02:49:15 +07:00
|
|
|
} while (0)
|
|
|
|
|
2006-07-22 20:37:43 +07:00
|
|
|
/*
|
|
|
|
* 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; \
|
|
|
|
})
|
|
|
|
|
[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-10-01 01:45:40 +07:00
|
|
|
#endif /* CONFIG_BLOCK */
|
2005-04-17 05:20:36 +07:00
|
|
|
#endif
|