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 KO |
22 | struct iov_iter { |
23 | const struct iovec *iov; | |
24 | unsigned long nr_segs; | |
25 | size_t iov_offset; | |
26 | size_t count; | |
27 | }; | |
28 | ||
1da177e4 LT |
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 | */ | |
36 | static 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 | ||
92236878 KO |
46 | static 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 | ||
1da177e4 | 61 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to); |
d2f83e90 | 62 | |
92236878 KO |
63 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
64 | struct iov_iter *i, unsigned long offset, size_t bytes); | |
65 | size_t iov_iter_copy_from_user(struct page *page, | |
66 | struct iov_iter *i, unsigned long offset, size_t bytes); | |
67 | void iov_iter_advance(struct iov_iter *i, size_t bytes); | |
68 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes); | |
69 | size_t iov_iter_single_seg_count(const struct iov_iter *i); | |
70 | ||
71 | static inline void iov_iter_init(struct iov_iter *i, | |
72 | const struct iovec *iov, unsigned long nr_segs, | |
73 | size_t count, size_t written) | |
74 | { | |
75 | i->iov = iov; | |
76 | i->nr_segs = nr_segs; | |
77 | i->iov_offset = 0; | |
78 | i->count = count + written; | |
79 | ||
80 | iov_iter_advance(i, written); | |
81 | } | |
82 | ||
83 | static inline size_t iov_iter_count(struct iov_iter *i) | |
84 | { | |
85 | return i->count; | |
86 | } | |
87 | ||
d2f83e90 RR |
88 | int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len); |
89 | int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len); | |
92236878 | 90 | |
812ed032 | 91 | #endif |