Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * Berkeley style UIO structures - Alan Cox 1994.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9#ifndef __LINUX_UIO_H
10#define __LINUX_UIO_H
11
12#include <linux/kernel.h>
13#include <uapi/linux/uio.h>
14
15struct page;
16
17struct kvec {
18 void *iov_base; /* and that should *never* hold a userland pointer */
19 size_t iov_len;
20};
21
22struct iov_iter {
23 const struct iovec *iov;
24 unsigned long nr_segs;
25 size_t iov_offset;
26 size_t count;
27};
28
29/*
30 * Total number of bytes covered by an iovec.
31 *
32 * NOTE that it is not safe to use this function until all the iovec's
33 * segment lengths have been validated. Because the individual lengths can
34 * overflow a size_t when added together.
35 */
36static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
37{
38 unsigned long seg;
39 size_t ret = 0;
40
41 for (seg = 0; seg < nr_segs; seg++)
42 ret += iov[seg].iov_len;
43 return ret;
44}
45
46static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
47{
48 return (struct iovec) {
49 .iov_base = iter->iov->iov_base + iter->iov_offset,
50 .iov_len = min(iter->count,
51 iter->iov->iov_len - iter->iov_offset),
52 };
53}
54
55#define iov_for_each(iov, iter, start) \
56 for (iter = (start); \
57 (iter).count && \
58 ((iov = iov_iter_iovec(&(iter))), 1); \
59 iov_iter_advance(&(iter), (iov).iov_len))
60
61unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
62
63size_t iov_iter_copy_from_user_atomic(struct page *page,
64 struct iov_iter *i, unsigned long offset, size_t bytes);
65size_t iov_iter_copy_from_user(struct page *page,
66 struct iov_iter *i, unsigned long offset, size_t bytes);
67void iov_iter_advance(struct iov_iter *i, size_t bytes);
68int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
69size_t iov_iter_single_seg_count(const struct iov_iter *i);
70size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
71 struct iov_iter *i);
72
73static inline void iov_iter_init(struct iov_iter *i,
74 const struct iovec *iov, unsigned long nr_segs,
75 size_t count, size_t written)
76{
77 i->iov = iov;
78 i->nr_segs = nr_segs;
79 i->iov_offset = 0;
80 i->count = count + written;
81
82 iov_iter_advance(i, written);
83}
84
85static inline size_t iov_iter_count(struct iov_iter *i)
86{
87 return i->count;
88}
89
90int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
91int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len);
92
93#endif