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>
16 struct pipe_inode_info;
19 void *iov_base; /* and that should *never* hold a userland pointer */
35 const struct iovec *iov;
36 const struct kvec *kvec;
37 const struct bio_vec *bvec;
38 struct pipe_inode_info *pipe;
41 unsigned long nr_segs;
50 * Total number of bytes covered by an iovec.
52 * NOTE that it is not safe to use this function until all the iovec's
53 * segment lengths have been validated. Because the individual lengths can
54 * overflow a size_t when added together.
56 static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
61 for (seg = 0; seg < nr_segs; seg++)
62 ret += iov[seg].iov_len;
66 static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
68 return (struct iovec) {
69 .iov_base = iter->iov->iov_base + iter->iov_offset,
70 .iov_len = min(iter->count,
71 iter->iov->iov_len - iter->iov_offset),
75 #define iov_for_each(iov, iter, start) \
76 if (!((start).type & (ITER_BVEC | ITER_PIPE))) \
77 for (iter = (start); \
79 ((iov = iov_iter_iovec(&(iter))), 1); \
80 iov_iter_advance(&(iter), (iov).iov_len))
82 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
84 size_t iov_iter_copy_from_user_atomic(struct page *page,
85 struct iov_iter *i, unsigned long offset, size_t bytes);
86 void iov_iter_advance(struct iov_iter *i, size_t bytes);
87 void iov_iter_revert(struct iov_iter *i, size_t bytes);
88 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
89 size_t iov_iter_single_seg_count(const struct iov_iter *i);
90 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
92 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
94 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
95 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
96 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
97 size_t iov_iter_zero(size_t bytes, struct iov_iter *);
98 unsigned long iov_iter_alignment(const struct iov_iter *i);
99 unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
100 void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
101 unsigned long nr_segs, size_t count);
102 void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec,
103 unsigned long nr_segs, size_t count);
104 void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec,
105 unsigned long nr_segs, size_t count);
106 void iov_iter_pipe(struct iov_iter *i, int direction, struct pipe_inode_info *pipe,
108 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
109 size_t maxsize, unsigned maxpages, size_t *start);
110 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
111 size_t maxsize, size_t *start);
112 int iov_iter_npages(const struct iov_iter *i, int maxpages);
114 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
116 static inline size_t iov_iter_count(const struct iov_iter *i)
121 static inline bool iter_is_iovec(const struct iov_iter *i)
123 return !(i->type & (ITER_BVEC | ITER_KVEC | ITER_PIPE));
127 * Get one of READ or WRITE out of iter->type without any other flags OR'd in
130 * The ?: is just for type safety.
132 #define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & RW_MASK)
135 * Cap the iov_iter by given limit; note that the second argument is
136 * *not* the new size - it's upper limit for such. Passing it a value
137 * greater than the amount of data in iov_iter is fine - it'll just do
138 * nothing in that case.
140 static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
143 * count doesn't have to fit in size_t - comparison extends both
144 * operands to u64 here and any value that would be truncated by
145 * conversion in assignement is by definition greater than all
146 * values of size_t, including old i->count.
148 if (i->count > count)
153 * reexpand a previously truncated iterator; count must be no more than how much
156 static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
160 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
161 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
163 int import_iovec(int type, const struct iovec __user * uvector,
164 unsigned nr_segs, unsigned fast_segs,
165 struct iovec **iov, struct iov_iter *i);
169 int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
170 unsigned nr_segs, unsigned fast_segs,
171 struct iovec **iov, struct iov_iter *i);
174 int import_single_range(int type, void __user *buf, size_t len,
175 struct iovec *iov, struct iov_iter *i);