Edit File: dm-kcopyd.h
/* * 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 */