Commit | Line | Data |
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1da177e4 LT |
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 | */ | |
607ca46e DH |
9 | #ifndef __LINUX_UIO_H |
10 | #define __LINUX_UIO_H | |
1da177e4 | 11 | |
92236878 | 12 | #include <linux/kernel.h> |
607ca46e | 13 | #include <uapi/linux/uio.h> |
1da177e4 | 14 | |
92236878 | 15 | struct page; |
812ed032 JS |
16 | |
17 | struct kvec { | |
18 | void *iov_base; /* and that should *never* hold a userland pointer */ | |
19 | size_t iov_len; | |
20 | }; | |
21 | ||
92236878 | 22 | struct iov_iter { |
71d8e532 | 23 | int type; |
92236878 KO |
24 | const struct iovec *iov; |
25 | unsigned long nr_segs; | |
26 | size_t iov_offset; | |
27 | size_t count; | |
28 | }; | |
29 | ||
1da177e4 LT |
30 | /* |
31 | * Total number of bytes covered by an iovec. | |
32 | * | |
33 | * NOTE that it is not safe to use this function until all the iovec's | |
34 | * segment lengths have been validated. Because the individual lengths can | |
35 | * overflow a size_t when added together. | |
36 | */ | |
37 | static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) | |
38 | { | |
39 | unsigned long seg; | |
40 | size_t ret = 0; | |
41 | ||
42 | for (seg = 0; seg < nr_segs; seg++) | |
43 | ret += iov[seg].iov_len; | |
44 | return ret; | |
45 | } | |
46 | ||
92236878 KO |
47 | static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) |
48 | { | |
49 | return (struct iovec) { | |
50 | .iov_base = iter->iov->iov_base + iter->iov_offset, | |
51 | .iov_len = min(iter->count, | |
52 | iter->iov->iov_len - iter->iov_offset), | |
53 | }; | |
54 | } | |
55 | ||
56 | #define iov_for_each(iov, iter, start) \ | |
57 | for (iter = (start); \ | |
58 | (iter).count && \ | |
59 | ((iov = iov_iter_iovec(&(iter))), 1); \ | |
60 | iov_iter_advance(&(iter), (iov).iov_len)) | |
61 | ||
1da177e4 | 62 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to); |
d2f83e90 | 63 | |
92236878 KO |
64 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
65 | struct iov_iter *i, unsigned long offset, size_t bytes); | |
92236878 KO |
66 | void iov_iter_advance(struct iov_iter *i, size_t bytes); |
67 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes); | |
68 | size_t iov_iter_single_seg_count(const struct iov_iter *i); | |
6e58e79d AV |
69 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
70 | struct iov_iter *i); | |
886a3911 | 71 | unsigned long iov_iter_alignment(const struct iov_iter *i); |
71d8e532 AV |
72 | void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov, |
73 | unsigned long nr_segs, size_t count); | |
7b2c99d1 AV |
74 | ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, |
75 | size_t maxsize, size_t *start); | |
92236878 KO |
76 | |
77 | static inline size_t iov_iter_count(struct iov_iter *i) | |
78 | { | |
79 | return i->count; | |
80 | } | |
81 | ||
d2f83e90 RR |
82 | int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len); |
83 | int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len); | |
92236878 | 84 | |
886a3911 | 85 | |
812ed032 | 86 | #endif |