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