2 * Berkeley style UIO structures - Alan Cox 1994.
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.
12 #include <linux/kernel.h>
13 #include <uapi/linux/uio.h>
18 void *iov_base
; /* and that should *never* hold a userland pointer */
33 const struct iovec
*iov
;
34 const struct kvec
*kvec
;
35 const struct bio_vec
*bvec
;
37 unsigned long nr_segs
;
41 * Total number of bytes covered by an iovec.
43 * NOTE that it is not safe to use this function until all the iovec's
44 * segment lengths have been validated. Because the individual lengths can
45 * overflow a size_t when added together.
47 static inline size_t iov_length(const struct iovec
*iov
, unsigned long nr_segs
)
52 for (seg
= 0; seg
< nr_segs
; seg
++)
53 ret
+= iov
[seg
].iov_len
;
57 static inline struct iovec
iov_iter_iovec(const struct iov_iter
*iter
)
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
),
66 #define iov_for_each(iov, iter, start) \
67 if (!((start).type & ITER_BVEC)) \
68 for (iter = (start); \
70 ((iov = iov_iter_iovec(&(iter))), 1); \
71 iov_iter_advance(&(iter), (iov).iov_len))
73 unsigned long iov_shorten(struct iovec
*iov
, unsigned long nr_segs
, size_t to
);
75 size_t iov_iter_copy_from_user_atomic(struct page
*page
,
76 struct iov_iter
*i
, unsigned long offset
, size_t bytes
);
77 void iov_iter_advance(struct iov_iter
*i
, size_t bytes
);
78 int iov_iter_fault_in_readable(struct iov_iter
*i
, size_t bytes
);
79 int iov_iter_fault_in_multipages_readable(struct iov_iter
*i
, size_t bytes
);
80 size_t iov_iter_single_seg_count(const struct iov_iter
*i
);
81 size_t copy_page_to_iter(struct page
*page
, size_t offset
, size_t bytes
,
83 size_t copy_page_from_iter(struct page
*page
, size_t offset
, size_t bytes
,
85 size_t copy_to_iter(const void *addr
, size_t bytes
, struct iov_iter
*i
);
86 size_t copy_from_iter(void *addr
, size_t bytes
, struct iov_iter
*i
);
87 size_t copy_from_iter_nocache(void *addr
, size_t bytes
, struct iov_iter
*i
);
88 size_t iov_iter_zero(size_t bytes
, struct iov_iter
*);
89 unsigned long iov_iter_alignment(const struct iov_iter
*i
);
90 void iov_iter_init(struct iov_iter
*i
, int direction
, const struct iovec
*iov
,
91 unsigned long nr_segs
, size_t count
);
92 void iov_iter_kvec(struct iov_iter
*i
, int direction
, const struct kvec
*kvec
,
93 unsigned long nr_segs
, size_t count
);
94 void iov_iter_bvec(struct iov_iter
*i
, int direction
, const struct bio_vec
*bvec
,
95 unsigned long nr_segs
, size_t count
);
96 ssize_t
iov_iter_get_pages(struct iov_iter
*i
, struct page
**pages
,
97 size_t maxsize
, unsigned maxpages
, size_t *start
);
98 ssize_t
iov_iter_get_pages_alloc(struct iov_iter
*i
, struct page
***pages
,
99 size_t maxsize
, size_t *start
);
100 int iov_iter_npages(const struct iov_iter
*i
, int maxpages
);
102 const void *dup_iter(struct iov_iter
*new, struct iov_iter
*old
, gfp_t flags
);
104 static inline size_t iov_iter_count(struct iov_iter
*i
)
109 static inline bool iter_is_iovec(struct iov_iter
*i
)
111 return !(i
->type
& (ITER_BVEC
| ITER_KVEC
));
115 * Get one of READ or WRITE out of iter->type without any other flags OR'd in
118 * The ?: is just for type safety.
120 #define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & RW_MASK)
123 * Cap the iov_iter by given limit; note that the second argument is
124 * *not* the new size - it's upper limit for such. Passing it a value
125 * greater than the amount of data in iov_iter is fine - it'll just do
126 * nothing in that case.
128 static inline void iov_iter_truncate(struct iov_iter
*i
, u64 count
)
131 * count doesn't have to fit in size_t - comparison extends both
132 * operands to u64 here and any value that would be truncated by
133 * conversion in assignement is by definition greater than all
134 * values of size_t, including old i->count.
136 if (i
->count
> count
)
141 * reexpand a previously truncated iterator; count must be no more than how much
144 static inline void iov_iter_reexpand(struct iov_iter
*i
, size_t count
)
148 size_t csum_and_copy_to_iter(const void *addr
, size_t bytes
, __wsum
*csum
, struct iov_iter
*i
);
149 size_t csum_and_copy_from_iter(void *addr
, size_t bytes
, __wsum
*csum
, struct iov_iter
*i
);
151 int import_iovec(int type
, const struct iovec __user
* uvector
,
152 unsigned nr_segs
, unsigned fast_segs
,
153 struct iovec
**iov
, struct iov_iter
*i
);
157 int 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
);
162 int import_single_range(int type
, void __user
*buf
, size_t len
,
163 struct iovec
*iov
, struct iov_iter
*i
);
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