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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;
19 size_t iov_len;
20};
21
22enum {
23 ITER_IOVEC = 0,
24 ITER_KVEC = 2,
25 ITER_BVEC = 4,
26};
27
28struct iov_iter {
29 int type;
30 size_t iov_offset;
31 size_t count;
32 union {
33 const struct iovec *iov;
34 const struct kvec *kvec;
35 const struct bio_vec *bvec;
36 };
37 unsigned long nr_segs;
38};
39
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45
46
47static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
48{
49 unsigned long seg;
50 size_t ret = 0;
51
52 for (seg = 0; seg < nr_segs; seg++)
53 ret += iov[seg].iov_len;
54 return ret;
55}
56
57static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
58{
59 return (struct iovec) {
60 .iov_base = iter->iov->iov_base + iter->iov_offset,
61 .iov_len = min(iter->count,
62 iter->iov->iov_len - iter->iov_offset),
63 };
64}
65
66#define iov_for_each(iov, iter, start) \
67 if (!((start).type & ITER_BVEC)) \
68 for (iter = (start); \
69 (iter).count && \
70 ((iov = iov_iter_iovec(&(iter))), 1); \
71 iov_iter_advance(&(iter), (iov).iov_len))
72
73unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
74
75size_t iov_iter_copy_from_user_atomic(struct page *page,
76 struct iov_iter *i, unsigned long offset, size_t bytes);
77void iov_iter_advance(struct iov_iter *i, size_t bytes);
78int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
79int iov_iter_fault_in_multipages_readable(struct iov_iter *i, size_t bytes);
80size_t iov_iter_single_seg_count(const struct iov_iter *i);
81size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
82 struct iov_iter *i);
83size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
84 struct iov_iter *i);
85size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i);
86size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
87size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
88size_t iov_iter_zero(size_t bytes, struct iov_iter *);
89unsigned long iov_iter_alignment(const struct iov_iter *i);
90void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
91 unsigned long nr_segs, size_t count);
92void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec,
93 unsigned long nr_segs, size_t count);
94void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec,
95 unsigned long nr_segs, size_t count);
96ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
97 size_t maxsize, unsigned maxpages, size_t *start);
98ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
99 size_t maxsize, size_t *start);
100int iov_iter_npages(const struct iov_iter *i, int maxpages);
101
102const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
103
104static inline size_t iov_iter_count(struct iov_iter *i)
105{
106 return i->count;
107}
108
109static inline bool iter_is_iovec(struct iov_iter *i)
110{
111 return !(i->type & (ITER_BVEC | ITER_KVEC));
112}
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120#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & RW_MASK)
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128static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
129{
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136 if (i->count > count)
137 i->count = count;
138}
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144static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
145{
146 i->count = count;
147}
148size_t csum_and_copy_to_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
149size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
150
151int import_iovec(int type, const struct iovec __user * uvector,
152 unsigned nr_segs, unsigned fast_segs,
153 struct iovec **iov, struct iov_iter *i);
154
155#ifdef CONFIG_COMPAT
156struct compat_iovec;
157int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
158 unsigned nr_segs, unsigned fast_segs,
159 struct iovec **iov, struct iov_iter *i);
160#endif
161
162int import_single_range(int type, void __user *buf, size_t len,
163 struct iovec *iov, struct iov_iter *i);
164
165#endif
166