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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 struct 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
24 struct 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
37
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 */
45 static 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
55 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
56
57 #endif