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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef __LINUX_UIO_H
2#define __LINUX_UIO_H
3
4#include <linux/compiler.h>
5#include <linux/types.h>
6
7/*
8 * Berkeley style UIO structures - Alan Cox 1994.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
Linus Torvalds1da177e2005-04-16 15:20:36 -070016struct iovec
17{
18 void __user *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */
19 __kernel_size_t iov_len; /* Must be size_t (1003.1g) */
20};
21
Linus Torvalds1da177e2005-04-16 15:20:36 -070022/*
23 * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1)
24 */
25
26#define UIO_FASTIOV 8
27#define UIO_MAXIOV 1024
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
Jiri Slaby812ed032009-07-29 15:04:19 -070029#ifdef __KERNEL__
30
31struct kvec {
32 void *iov_base; /* and that should *never* hold a userland pointer */
33 size_t iov_len;
34};
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036/*
37 * Total number of bytes covered by an iovec.
38 *
39 * NOTE that it is not safe to use this function until all the iovec's
40 * segment lengths have been validated. Because the individual lengths can
41 * overflow a size_t when added together.
42 */
43static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
44{
45 unsigned long seg;
46 size_t ret = 0;
47
48 for (seg = 0; seg < nr_segs; seg++)
49 ret += iov[seg].iov_len;
50 return ret;
51}
52
53unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
Jiri Slaby812ed032009-07-29 15:04:19 -070054#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
56#endif