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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - include/linux/uio.h
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 */
24 const struct iovec
*iov
;
25 unsigned long nr_segs
;
31 * Total number of bytes covered by an iovec.
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.
37 static inline size_t iov_length(const struct iovec
*iov
, unsigned long nr_segs
)
42 for (seg
= 0; seg
< nr_segs
; seg
++)
43 ret
+= iov
[seg
].iov_len
;
47 static inline struct iovec
iov_iter_iovec(const struct iov_iter
*iter
)
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
),
56 #define iov_for_each(iov, iter, start) \
57 for (iter = (start); \
59 ((iov = iov_iter_iovec(&(iter))), 1); \
60 iov_iter_advance(&(iter), (iov).iov_len))
62 unsigned long iov_shorten(struct iovec
*iov
, unsigned long nr_segs
, size_t to
);
64 size_t iov_iter_copy_from_user_atomic(struct page
*page
,
65 struct iov_iter
*i
, unsigned long offset
, size_t bytes
);
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
);
69 size_t copy_page_to_iter(struct page
*page
, size_t offset
, size_t bytes
,
71 unsigned long iov_iter_alignment(const struct iov_iter
*i
);
72 void iov_iter_init(struct iov_iter
*i
, int direction
, const struct iovec
*iov
,
73 unsigned long nr_segs
, size_t count
);
74 ssize_t
iov_iter_get_pages(struct iov_iter
*i
, struct page
**pages
,
75 size_t maxsize
, size_t *start
);
77 static inline size_t iov_iter_count(struct iov_iter
*i
)
82 int memcpy_fromiovec(unsigned char *kdata
, struct iovec
*iov
, int len
);
83 int memcpy_toiovec(struct iovec
*iov
, unsigned char *kdata
, int len
);