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 #define DM_KCOPYD_WRITE_SEQ 2 24 25 struct dm_kcopyd_throttle { 26 unsigned throttle; 27 unsigned num_io_jobs; 28 unsigned io_period; 29 unsigned total_period; 30 unsigned last_jiffies; 31 }; 32 33 /* 34 * kcopyd clients that want to support throttling must pass an initialised 35 * dm_kcopyd_throttle struct into dm_kcopyd_client_create(). 36 * Two or more clients may share the same instance of this struct between 37 * them if they wish to be throttled as a group. 38 * 39 * This macro also creates a corresponding module parameter to configure 40 * the amount of throttling. 41 */ 42 #define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) \ 43 static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \ 44 module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \ 45 MODULE_PARM_DESC(name, description) 46 47 /* 48 * To use kcopyd you must first create a dm_kcopyd_client object. 49 * throttle can be NULL if you don't want any throttling. 50 */ 51 struct dm_kcopyd_client; 52 struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle); 53 void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc); 54 void dm_kcopyd_client_flush(struct dm_kcopyd_client *kc); 55 56 /* 57 * Submit a copy job to kcopyd. This is built on top of the 58 * previous three fns. 59 * 60 * read_err is a boolean, 61 * write_err is a bitset, with 1 bit for each destination region 62 */ 63 typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned long write_err, 64 void *context); 65 66 void dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, 67 unsigned num_dests, struct dm_io_region *dests, 68 unsigned flags, dm_kcopyd_notify_fn fn, void *context); 69 70 /* 71 * Prepare a callback and submit it via the kcopyd thread. 72 * 73 * dm_kcopyd_prepare_callback allocates a callback structure and returns it. 74 * It must not be called from interrupt context. 75 * The returned value should be passed into dm_kcopyd_do_callback. 76 * 77 * dm_kcopyd_do_callback submits the callback. 78 * It may be called from interrupt context. 79 * The callback is issued from the kcopyd thread. 80 */ 81 void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc, 82 dm_kcopyd_notify_fn fn, void *context); 83 void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err); 84 85 void dm_kcopyd_zero(struct dm_kcopyd_client *kc, 86 unsigned num_dests, struct dm_io_region *dests, 87 unsigned flags, dm_kcopyd_notify_fn fn, void *context); 88 89 #endif /* __KERNEL__ */ 90 #endif /* _LINUX_DM_KCOPYD_H */ 91