Line data Source code
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 : /*
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
28 :
29 : #ifdef __KERNEL__
30 :
31 : struct kvec {
32 : void *iov_base; /* and that should *never* hold a userland pointer */
33 : size_t iov_len;
34 : };
35 :
36 : /*
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 : */
43 : static 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 :
53 : unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
54 1 : #endif
55 3 :
56 : #endif
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