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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
22#ifdef __KERNEL__
23
24struct kvec {
25 void *iov_base; /* and that should *never* hold a userland pointer */
26 size_t iov_len;
27};
28
29#endif
30
31/*
32 * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1)
33 */
34
35#define UIO_FASTIOV 8
36#define UIO_MAXIOV 1024
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38/*
39 * Total number of bytes covered by an iovec.
40 *
41 * NOTE that it is not safe to use this function until all the iovec's
42 * segment lengths have been validated. Because the individual lengths can
43 * overflow a size_t when added together.
44 */
45static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
46{
47 unsigned long seg;
48 size_t ret = 0;
49
50 for (seg = 0; seg < nr_segs; seg++)
51 ret += iov[seg].iov_len;
52 return ret;
53}
54
55unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
56
57#endif