7f06965390
This patch introduces dm_kcopyd_zero() to make it easy to use kcopyd to write zeros into the requested areas instead instead of copying. It is implemented by passing a NULL copying source to dm_kcopyd_copy(). The forthcoming thin provisioning target uses this. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
65 lines
2 KiB
C
65 lines
2 KiB
C
/*
|
|
* 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
|
|
|
|
/*
|
|
* To use kcopyd you must first create a dm_kcopyd_client object.
|
|
*/
|
|
struct dm_kcopyd_client;
|
|
struct dm_kcopyd_client *dm_kcopyd_client_create(void);
|
|
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 */
|