7d76345da6
This patch adds the following target interfaces for request-based dm.
map_rq : for mapping a request
rq_end_io : for finishing a request
busy : for avoiding performance regression from bio-based dm.
Target can tell dm core not to map requests now, and
that may help requests in the block layer queue to be
bigger by I/O merging.
In bio-based dm, this behavior is done by device
drivers managing the block layer queue.
But in request-based dm, dm core has to do that
since dm core manages the block layer queue.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
387 lines
9.9 KiB
C
387 lines
9.9 KiB
C
/*
|
|
* Copyright (C) 2001 Sistina Software (UK) Limited.
|
|
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
|
|
*
|
|
* This file is released under the LGPL.
|
|
*/
|
|
|
|
#ifndef _LINUX_DEVICE_MAPPER_H
|
|
#define _LINUX_DEVICE_MAPPER_H
|
|
|
|
#include <linux/bio.h>
|
|
#include <linux/blkdev.h>
|
|
|
|
struct dm_target;
|
|
struct dm_table;
|
|
struct mapped_device;
|
|
struct bio_vec;
|
|
|
|
typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
|
|
|
|
union map_info {
|
|
void *ptr;
|
|
unsigned long long ll;
|
|
};
|
|
|
|
/*
|
|
* In the constructor the target parameter will already have the
|
|
* table, type, begin and len fields filled in.
|
|
*/
|
|
typedef int (*dm_ctr_fn) (struct dm_target *target,
|
|
unsigned int argc, char **argv);
|
|
|
|
/*
|
|
* The destructor doesn't need to free the dm_target, just
|
|
* anything hidden ti->private.
|
|
*/
|
|
typedef void (*dm_dtr_fn) (struct dm_target *ti);
|
|
|
|
/*
|
|
* The map function must return:
|
|
* < 0: error
|
|
* = 0: The target will handle the io by resubmitting it later
|
|
* = 1: simple remap complete
|
|
* = 2: The target wants to push back the io
|
|
*/
|
|
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
|
|
union map_info *map_context);
|
|
typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
|
|
union map_info *map_context);
|
|
|
|
/*
|
|
* Returns:
|
|
* < 0 : error (currently ignored)
|
|
* 0 : ended successfully
|
|
* 1 : for some reason the io has still not completed (eg,
|
|
* multipath target might want to requeue a failed io).
|
|
* 2 : The target wants to push back the io
|
|
*/
|
|
typedef int (*dm_endio_fn) (struct dm_target *ti,
|
|
struct bio *bio, int error,
|
|
union map_info *map_context);
|
|
typedef int (*dm_request_endio_fn) (struct dm_target *ti,
|
|
struct request *clone, int error,
|
|
union map_info *map_context);
|
|
|
|
typedef void (*dm_flush_fn) (struct dm_target *ti);
|
|
typedef void (*dm_presuspend_fn) (struct dm_target *ti);
|
|
typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
|
|
typedef int (*dm_preresume_fn) (struct dm_target *ti);
|
|
typedef void (*dm_resume_fn) (struct dm_target *ti);
|
|
|
|
typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
|
|
char *result, unsigned int maxlen);
|
|
|
|
typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
|
|
|
|
typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
|
|
unsigned long arg);
|
|
|
|
typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
|
|
struct bio_vec *biovec, int max_size);
|
|
|
|
/*
|
|
* Returns:
|
|
* 0: The target can handle the next I/O immediately.
|
|
* 1: The target can't handle the next I/O immediately.
|
|
*/
|
|
typedef int (*dm_busy_fn) (struct dm_target *ti);
|
|
|
|
void dm_error(const char *message);
|
|
|
|
/*
|
|
* Combine device limits.
|
|
*/
|
|
void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
|
|
|
|
struct dm_dev {
|
|
struct block_device *bdev;
|
|
fmode_t mode;
|
|
char name[16];
|
|
};
|
|
|
|
/*
|
|
* Constructors should call these functions to ensure destination devices
|
|
* are opened/closed correctly.
|
|
* FIXME: too many arguments.
|
|
*/
|
|
int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
|
|
sector_t len, fmode_t mode, struct dm_dev **result);
|
|
void dm_put_device(struct dm_target *ti, struct dm_dev *d);
|
|
|
|
/*
|
|
* Information about a target type
|
|
*/
|
|
struct target_type {
|
|
const char *name;
|
|
struct module *module;
|
|
unsigned version[3];
|
|
dm_ctr_fn ctr;
|
|
dm_dtr_fn dtr;
|
|
dm_map_fn map;
|
|
dm_map_request_fn map_rq;
|
|
dm_endio_fn end_io;
|
|
dm_request_endio_fn rq_end_io;
|
|
dm_flush_fn flush;
|
|
dm_presuspend_fn presuspend;
|
|
dm_postsuspend_fn postsuspend;
|
|
dm_preresume_fn preresume;
|
|
dm_resume_fn resume;
|
|
dm_status_fn status;
|
|
dm_message_fn message;
|
|
dm_ioctl_fn ioctl;
|
|
dm_merge_fn merge;
|
|
dm_busy_fn busy;
|
|
};
|
|
|
|
struct io_restrictions {
|
|
unsigned long bounce_pfn;
|
|
unsigned long seg_boundary_mask;
|
|
unsigned max_hw_sectors;
|
|
unsigned max_sectors;
|
|
unsigned max_segment_size;
|
|
unsigned short hardsect_size;
|
|
unsigned short max_hw_segments;
|
|
unsigned short max_phys_segments;
|
|
unsigned char no_cluster; /* inverted so that 0 is default */
|
|
};
|
|
|
|
struct dm_target {
|
|
struct dm_table *table;
|
|
struct target_type *type;
|
|
|
|
/* target limits */
|
|
sector_t begin;
|
|
sector_t len;
|
|
|
|
/* FIXME: turn this into a mask, and merge with io_restrictions */
|
|
/* Always a power of 2 */
|
|
sector_t split_io;
|
|
|
|
/*
|
|
* These are automatically filled in by
|
|
* dm_table_get_device.
|
|
*/
|
|
struct io_restrictions limits;
|
|
|
|
/* target specific data */
|
|
void *private;
|
|
|
|
/* Used to provide an error string from the ctr */
|
|
char *error;
|
|
};
|
|
|
|
int dm_register_target(struct target_type *t);
|
|
void dm_unregister_target(struct target_type *t);
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Functions for creating and manipulating mapped devices.
|
|
* Drop the reference with dm_put when you finish with the object.
|
|
*---------------------------------------------------------------*/
|
|
|
|
/*
|
|
* DM_ANY_MINOR chooses the next available minor number.
|
|
*/
|
|
#define DM_ANY_MINOR (-1)
|
|
int dm_create(int minor, struct mapped_device **md);
|
|
|
|
/*
|
|
* Reference counting for md.
|
|
*/
|
|
struct mapped_device *dm_get_md(dev_t dev);
|
|
void dm_get(struct mapped_device *md);
|
|
void dm_put(struct mapped_device *md);
|
|
|
|
/*
|
|
* An arbitrary pointer may be stored alongside a mapped device.
|
|
*/
|
|
void dm_set_mdptr(struct mapped_device *md, void *ptr);
|
|
void *dm_get_mdptr(struct mapped_device *md);
|
|
|
|
/*
|
|
* A device can still be used while suspended, but I/O is deferred.
|
|
*/
|
|
int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
|
|
int dm_resume(struct mapped_device *md);
|
|
|
|
/*
|
|
* Event functions.
|
|
*/
|
|
uint32_t dm_get_event_nr(struct mapped_device *md);
|
|
int dm_wait_event(struct mapped_device *md, int event_nr);
|
|
uint32_t dm_next_uevent_seq(struct mapped_device *md);
|
|
void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
|
|
|
|
/*
|
|
* Info functions.
|
|
*/
|
|
const char *dm_device_name(struct mapped_device *md);
|
|
int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
|
|
struct gendisk *dm_disk(struct mapped_device *md);
|
|
int dm_suspended(struct mapped_device *md);
|
|
int dm_noflush_suspending(struct dm_target *ti);
|
|
union map_info *dm_get_mapinfo(struct bio *bio);
|
|
|
|
/*
|
|
* Geometry functions.
|
|
*/
|
|
int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
|
|
int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
|
|
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Functions for manipulating device-mapper tables.
|
|
*---------------------------------------------------------------*/
|
|
|
|
/*
|
|
* First create an empty table.
|
|
*/
|
|
int dm_table_create(struct dm_table **result, fmode_t mode,
|
|
unsigned num_targets, struct mapped_device *md);
|
|
|
|
/*
|
|
* Then call this once for each target.
|
|
*/
|
|
int dm_table_add_target(struct dm_table *t, const char *type,
|
|
sector_t start, sector_t len, char *params);
|
|
|
|
/*
|
|
* Finally call this to make the table ready for use.
|
|
*/
|
|
int dm_table_complete(struct dm_table *t);
|
|
|
|
/*
|
|
* Unplug all devices in a table.
|
|
*/
|
|
void dm_table_unplug_all(struct dm_table *t);
|
|
|
|
/*
|
|
* Table reference counting.
|
|
*/
|
|
struct dm_table *dm_get_table(struct mapped_device *md);
|
|
void dm_table_get(struct dm_table *t);
|
|
void dm_table_put(struct dm_table *t);
|
|
|
|
/*
|
|
* Queries
|
|
*/
|
|
sector_t dm_table_get_size(struct dm_table *t);
|
|
unsigned int dm_table_get_num_targets(struct dm_table *t);
|
|
fmode_t dm_table_get_mode(struct dm_table *t);
|
|
struct mapped_device *dm_table_get_md(struct dm_table *t);
|
|
|
|
/*
|
|
* Trigger an event.
|
|
*/
|
|
void dm_table_event(struct dm_table *t);
|
|
|
|
/*
|
|
* The device must be suspended before calling this method.
|
|
*/
|
|
int dm_swap_table(struct mapped_device *md, struct dm_table *t);
|
|
|
|
/*
|
|
* A wrapper around vmalloc.
|
|
*/
|
|
void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Macros.
|
|
*---------------------------------------------------------------*/
|
|
#define DM_NAME "device-mapper"
|
|
|
|
#define DMCRIT(f, arg...) \
|
|
printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
|
|
|
|
#define DMERR(f, arg...) \
|
|
printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
|
|
#define DMERR_LIMIT(f, arg...) \
|
|
do { \
|
|
if (printk_ratelimit()) \
|
|
printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
|
|
f "\n", ## arg); \
|
|
} while (0)
|
|
|
|
#define DMWARN(f, arg...) \
|
|
printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
|
|
#define DMWARN_LIMIT(f, arg...) \
|
|
do { \
|
|
if (printk_ratelimit()) \
|
|
printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
|
|
f "\n", ## arg); \
|
|
} while (0)
|
|
|
|
#define DMINFO(f, arg...) \
|
|
printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
|
|
#define DMINFO_LIMIT(f, arg...) \
|
|
do { \
|
|
if (printk_ratelimit()) \
|
|
printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
|
|
"\n", ## arg); \
|
|
} while (0)
|
|
|
|
#ifdef CONFIG_DM_DEBUG
|
|
# define DMDEBUG(f, arg...) \
|
|
printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
|
|
# define DMDEBUG_LIMIT(f, arg...) \
|
|
do { \
|
|
if (printk_ratelimit()) \
|
|
printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
|
|
"\n", ## arg); \
|
|
} while (0)
|
|
#else
|
|
# define DMDEBUG(f, arg...) do {} while (0)
|
|
# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
|
|
#endif
|
|
|
|
#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
|
|
0 : scnprintf(result + sz, maxlen - sz, x))
|
|
|
|
#define SECTOR_SHIFT 9
|
|
|
|
/*
|
|
* Definitions of return values from target end_io function.
|
|
*/
|
|
#define DM_ENDIO_INCOMPLETE 1
|
|
#define DM_ENDIO_REQUEUE 2
|
|
|
|
/*
|
|
* Definitions of return values from target map function.
|
|
*/
|
|
#define DM_MAPIO_SUBMITTED 0
|
|
#define DM_MAPIO_REMAPPED 1
|
|
#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
|
|
|
|
/*
|
|
* Ceiling(n / sz)
|
|
*/
|
|
#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
|
|
|
|
#define dm_sector_div_up(n, sz) ( \
|
|
{ \
|
|
sector_t _r = ((n) + (sz) - 1); \
|
|
sector_div(_r, (sz)); \
|
|
_r; \
|
|
} \
|
|
)
|
|
|
|
/*
|
|
* ceiling(n / size) * size
|
|
*/
|
|
#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
|
|
|
|
#define dm_array_too_big(fixed, obj, num) \
|
|
((num) > (UINT_MAX - (fixed)) / (obj))
|
|
|
|
static inline sector_t to_sector(unsigned long n)
|
|
{
|
|
return (n >> SECTOR_SHIFT);
|
|
}
|
|
|
|
static inline unsigned long to_bytes(sector_t n)
|
|
{
|
|
return (n << SECTOR_SHIFT);
|
|
}
|
|
|
|
#endif /* _LINUX_DEVICE_MAPPER_H */
|