1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2001 - 2003 Sistina Software 4 * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved. 5 * 6 * kcopyd provides a simple interface for copying an area of one 7 * block-device to one or more other block-devices, either synchronous 8 * or with an asynchronous completion notification. 9 * 10 * This file is released under the GPL. 11 */ 12 13 #ifndef _LINUX_DM_KCOPYD_H 14 #define _LINUX_DM_KCOPYD_H 15 16 #ifdef __KERNEL__ 17 18 #include <linux/dm-io.h> 19 20 /* FIXME: make this configurable */ 21 #define DM_KCOPYD_MAX_REGIONS 8 22 23 #define DM_KCOPYD_IGNORE_ERROR 1 24 #define DM_KCOPYD_WRITE_SEQ 2 25 26 struct dm_kcopyd_throttle { 27 unsigned int throttle; 28 unsigned int num_io_jobs; 29 unsigned int io_period; 30 unsigned int total_period; 31 unsigned int last_jiffies; 32 }; 33 34 /* 35 * kcopyd clients that want to support throttling must pass an initialised 36 * dm_kcopyd_throttle struct into dm_kcopyd_client_create(). 37 * Two or more clients may share the same instance of this struct between 38 * them if they wish to be throttled as a group. 39 * 40 * This macro also creates a corresponding module parameter to configure 41 * the amount of throttling. 42 */ 43 #define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) \ 44 static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \ 45 module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \ 46 MODULE_PARM_DESC(name, description) 47 48 /* 49 * To use kcopyd you must first create a dm_kcopyd_client object. 50 * throttle can be NULL if you don't want any throttling. 51 */ 52 struct dm_kcopyd_client; 53 struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle); 54 void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc); 55 void dm_kcopyd_client_flush(struct dm_kcopyd_client *kc); 56 57 /* 58 * Submit a copy job to kcopyd. This is built on top of the 59 * previous three fns. 60 * 61 * read_err is a boolean, 62 * write_err is a bitset, with 1 bit for each destination region 63 */ 64 typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned int long write_err, 65 void *context); 66 67 void dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, 68 unsigned int num_dests, struct dm_io_region *dests, 69 unsigned int flags, dm_kcopyd_notify_fn fn, void *context); 70 71 /* 72 * Prepare a callback and submit it via the kcopyd thread. 73 * 74 * dm_kcopyd_prepare_callback allocates a callback structure and returns it. 75 * It must not be called from interrupt context. 76 * The returned value should be passed into dm_kcopyd_do_callback. 77 * 78 * dm_kcopyd_do_callback submits the callback. 79 * It may be called from interrupt context. 80 * The callback is issued from the kcopyd thread. 81 */ 82 void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc, 83 dm_kcopyd_notify_fn fn, void *context); 84 void dm_kcopyd_do_callback(void *job, int read_err, unsigned int long write_err); 85 86 void dm_kcopyd_zero(struct dm_kcopyd_client *kc, 87 unsigned int num_dests, struct dm_io_region *dests, 88 unsigned int flags, dm_kcopyd_notify_fn fn, void *context); 89 90 #endif /* __KERNEL__ */ 91 #endif /* _LINUX_DM_KCOPYD_H */ 92