/*
* Copyright (C) 2001 - 2003 Sistina Software
* Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.
*
* kcopyd provides a simple interface for copying an area of one
* block-device to one or more other block-devices, either synchronous
* or with an asynchronous completion notification.
*
* This file is released under the GPL.
*/

#ifndef _LINUX_DM_KCOPYD_H
#define _LINUX_DM_KCOPYD_H

#ifdef __KERNEL__

#include <linux/dm-io.h>

/* FIXME: make this configurable */
#define DM_KCOPYD_MAX_REGIONS 8

#define DM_KCOPYD_IGNORE_ERROR 1

struct dm_kcopyd_throttle {
unsigned throttle;
unsigned num_io_jobs;
unsigned io_period;
unsigned total_period;
unsigned last_jiffies;
};

/*
* kcopyd clients that want to support throttling must pass an initialised
* dm_kcopyd_throttle struct into dm_kcopyd_client_create().
* Two or more clients may share the same instance of this struct between
* them if they wish to be throttled as a group.
*
* This macro also creates a corresponding module parameter to configure
* the amount of throttling.
*/
#define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) \
static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \
module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \
MODULE_PARM_DESC(name, description)

/*
* To use kcopyd you must first create a dm_kcopyd_client object.
* throttle can be NULL if you don't want any throttling.
*/
struct dm_kcopyd_client;
struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle);
void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);

/*
* Submit a copy job to kcopyd. This is built on top of the
* previous three fns.
*
* read_err is a boolean,
* write_err is a bitset, with 1 bit for each destination region
*/
typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned long write_err,
void *context);

int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
unsigned num_dests, struct dm_io_region *dests,
unsigned flags, dm_kcopyd_notify_fn fn, void *context);

/*
* Prepare a callback and submit it via the kcopyd thread.
*
* dm_kcopyd_prepare_callback allocates a callback structure and returns it.
* It must not be called from interrupt context.
* The returned value should be passed into dm_kcopyd_do_callback.
*
* dm_kcopyd_do_callback submits the callback.
* It may be called from interrupt context.
* The callback is issued from the kcopyd thread.
*/
void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
dm_kcopyd_notify_fn fn, void *context);
void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err);

int dm_kcopyd_zero(struct dm_kcopyd_client *kc,
unsigned num_dests, struct dm_io_region *dests,
unsigned flags, dm_kcopyd_notify_fn fn, void *context);

#endif /* __KERNEL__ */
#endif /* _LINUX_DM_KCOPYD_H */