Linux kernel mirror (for testing)
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1#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
16
17/* A word of warning: Our uio structure will clash with the C library one (which is now obsolete). Remove the C
18 library one from sys/uio.h if you have a very old library set */
19
20struct iovec
21{
22 void __user *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */
23 __kernel_size_t iov_len; /* Must be size_t (1003.1g) */
24};
25
26#ifdef __KERNEL__
27
28struct kvec {
29 void *iov_base; /* and that should *never* hold a userland pointer */
30 size_t iov_len;
31};
32
33#endif
34
35/*
36 * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1)
37 */
38
39#define UIO_FASTIOV 8
40#define UIO_MAXIOV 1024
41#if 0
42#define UIO_MAXIOV 16 /* Maximum iovec's in one operation
43 16 matches BSD */
44 /* Beg pardon: BSD has 1024 --ANK */
45#endif
46
47/*
48 * Total number of bytes covered by an iovec.
49 *
50 * NOTE that it is not safe to use this function until all the iovec's
51 * segment lengths have been validated. Because the individual lengths can
52 * overflow a size_t when added together.
53 */
54static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
55{
56 unsigned long seg;
57 size_t ret = 0;
58
59 for (seg = 0; seg < nr_segs; seg++)
60 ret += iov[seg].iov_len;
61 return ret;
62}
63
64unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
65
66#endif