67 lines
1.6 KiB
C
67 lines
1.6 KiB
C
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#ifndef __LINUX_UIO_H
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#define __LINUX_UIO_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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/*
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* Berkeley style UIO structures - Alan Cox 1994.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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/* 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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library one from sys/uio.h if you have a very old library set */
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struct iovec
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{
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void __user *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */
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__kernel_size_t iov_len; /* Must be size_t (1003.1g) */
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};
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#ifdef __KERNEL__
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struct kvec {
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void *iov_base; /* and that should *never* hold a userland pointer */
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size_t iov_len;
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};
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#endif
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/*
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* UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1)
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*/
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#define UIO_FASTIOV 8
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#define UIO_MAXIOV 1024
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#if 0
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#define UIO_MAXIOV 16 /* Maximum iovec's in one operation
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16 matches BSD */
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/* Beg pardon: BSD has 1024 --ANK */
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#endif
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/*
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* Total number of bytes covered by an iovec.
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*
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* NOTE that it is not safe to use this function until all the iovec's
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* segment lengths have been validated. Because the individual lengths can
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* overflow a size_t when added together.
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*/
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static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
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{
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unsigned long seg;
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size_t ret = 0;
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for (seg = 0; seg < nr_segs; seg++)
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ret += iov[seg].iov_len;
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return ret;
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}
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unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
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#endif
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