1 ======
2 kcopyd
3 ======
4
5 Kcopyd provides the ability to copy a range of
6 to one or more other block-devices, with an as
7 notification. It is used by dm-snapshot and dm
8
9 Users of kcopyd must first create a client and
10 to set aside for their copy jobs. This is done
11 kcopyd_client_create()::
12
13 int kcopyd_client_create(unsigned int num_p
14 struct kcopyd_clie
15
16 To start a copy job, the user must set up io_r
17 the source and destinations of the copy. Each
18 block-device along with the starting sector an
19 of the copy is given as one io_region structur
20 copy are given as an array of io_region struct
21
22 struct io_region {
23 struct block_device *bdev;
24 sector_t sector;
25 sector_t count;
26 };
27
28 To start the copy, the user calls kcopyd_copy(
29 pointer, pointers to the source and destinatio
30 completion callback routine, and a pointer to
31
32 int kcopyd_copy(struct kcopyd_client *kc, s
33 unsigned int num_dests, str
34 unsigned int flags, kcopyd_
35
36 typedef void (*kcopyd_notify_fn)(int read_e
37 void *cont
38
39 When the copy completes, kcopyd will call the
40 passing back the user's context pointer. It wi
41 write error occurred during the copy.
42
43 When a user is done with all their copy jobs,
44 kcopyd_client_destroy() to delete the kcopyd c
45 associated memory pages::
46
47 void kcopyd_client_destroy(struct kcopyd_cl
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.