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 bio_vec
*bvec
;
36 unsigned long nr_segs
;
40 * Total number of bytes covered by an iovec.
42 * NOTE that it is not safe to use this function until all the iovec's
43 * segment lengths have been validated. Because the individual lengths can
44 * overflow a size_t when added together.
46 static inline size_t iov_length(const struct iovec
*iov
, unsigned long nr_segs
)
51 for (seg
= 0; seg
< nr_segs
; seg
++)
52 ret
+= iov
[seg
].iov_len
;
56 static inline struct iovec
iov_iter_iovec(const struct iov_iter
*iter
)
58 return (struct iovec
) {
59 .iov_base
= iter
->iov
->iov_base
+ iter
->iov_offset
,
60 .iov_len
= min(iter
->count
,
61 iter
->iov
->iov_len
- iter
->iov_offset
),
65 #define iov_for_each(iov, iter, start) \
66 if (!((start).type & ITER_BVEC)) \
67 for (iter = (start); \
69 ((iov = iov_iter_iovec(&(iter))), 1); \
70 iov_iter_advance(&(iter), (iov).iov_len))
72 unsigned long iov_shorten(struct iovec
*iov
, unsigned long nr_segs
, size_t to
);
74 size_t iov_iter_copy_from_user_atomic(struct page
*page
,
75 struct iov_iter
*i
, unsigned long offset
, size_t bytes
);
76 void iov_iter_advance(struct iov_iter
*i
, size_t bytes
);
77 int iov_iter_fault_in_readable(struct iov_iter
*i
, size_t bytes
);
78 size_t iov_iter_single_seg_count(const struct iov_iter
*i
);
79 size_t copy_page_to_iter(struct page
*page
, size_t offset
, size_t bytes
,
81 size_t copy_page_from_iter(struct page
*page
, size_t offset
, size_t bytes
,
83 unsigned long iov_iter_alignment(const struct iov_iter
*i
);
84 void iov_iter_init(struct iov_iter
*i
, int direction
, const struct iovec
*iov
,
85 unsigned long nr_segs
, size_t count
);
86 ssize_t
iov_iter_get_pages(struct iov_iter
*i
, struct page
**pages
,
87 unsigned maxpages
, size_t *start
);
88 ssize_t
iov_iter_get_pages_alloc(struct iov_iter
*i
, struct page
***pages
,
89 size_t maxsize
, size_t *start
);
90 int iov_iter_npages(const struct iov_iter
*i
, int maxpages
);
92 static inline size_t iov_iter_count(struct iov_iter
*i
)
98 * Cap the iov_iter by given limit; note that the second argument is
99 * *not* the new size - it's upper limit for such. Passing it a value
100 * greater than the amount of data in iov_iter is fine - it'll just do
101 * nothing in that case.
103 static inline void iov_iter_truncate(struct iov_iter
*i
, u64 count
)
106 * count doesn't have to fit in size_t - comparison extends both
107 * operands to u64 here and any value that would be truncated by
108 * conversion in assignement is by definition greater than all
109 * values of size_t, including old i->count.
111 if (i
->count
> count
)
116 * reexpand a previously truncated iterator; count must be no more than how much
119 static inline void iov_iter_reexpand(struct iov_iter
*i
, size_t count
)
124 int memcpy_fromiovec(unsigned char *kdata
, struct iovec
*iov
, int len
);
125 int memcpy_toiovec(struct iovec
*iov
, unsigned char *kdata
, int len
);
126 int memcpy_fromiovecend(unsigned char *kdata
, const struct iovec
*iov
,
127 int offset
, int len
);
128 int memcpy_toiovecend(const struct iovec
*v
, unsigned char *kdata
,
129 int offset
, int len
);