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422 | giacomo | 1 | #ifndef __LINUX_UIO_H |
2 | #define __LINUX_UIO_H |
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3 | |||
4 | #include <linux/compiler.h> |
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5 | #include <linux/types.h> |
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6 | |||
7 | /* |
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8 | * Berkeley style UIO structures - Alan Cox 1994. |
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9 | * |
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10 | * This program is free software; you can redistribute it and/or |
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11 | * modify it under the terms of the GNU General Public License |
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12 | * as published by the Free Software Foundation; either version |
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13 | * 2 of the License, or (at your option) any later version. |
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14 | */ |
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15 | |||
16 | |||
17 | /* A word of warning: Our uio structure will clash with the C library one (which is now obsolete). Remove the C |
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18 | library one from sys/uio.h if you have a very old library set */ |
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19 | |||
20 | struct iovec |
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21 | { |
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22 | void __user *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */ |
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23 | __kernel_size_t iov_len; /* Must be size_t (1003.1g) */ |
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24 | }; |
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25 | |||
26 | /* |
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27 | * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1) |
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28 | */ |
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29 | |||
30 | #define UIO_FASTIOV 8 |
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31 | #define UIO_MAXIOV 1024 |
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32 | #if 0 |
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33 | #define UIO_MAXIOV 16 /* Maximum iovec's in one operation |
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34 | 16 matches BSD */ |
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35 | /* Beg pardon: BSD has 1024 --ANK */ |
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36 | #endif |
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37 | |||
38 | /* |
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39 | * Total number of bytes covered by an iovec. |
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40 | * |
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41 | * NOTE that it is not safe to use this function until all the iovec's |
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42 | * segment lengths have been validated. Because the individual lengths can |
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43 | * overflow a size_t when added together. |
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44 | */ |
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45 | static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) |
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46 | { |
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47 | unsigned long seg; |
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48 | size_t ret = 0; |
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49 | |||
50 | for (seg = 0; seg < nr_segs; seg++) |
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51 | ret += iov[seg].iov_len; |
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52 | return ret; |
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53 | } |
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54 | |||
55 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to); |
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56 | |||
57 | #endif |