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 <linux/thread_info.h>
14 #include <crypto/hash.h>
15 #include <uapi/linux/uio.h>
18 struct pipe_inode_info;
21 void *iov_base; /* and that should *never* hold a userland pointer */
38 const struct iovec *iov;
39 const struct kvec *kvec;
40 const struct bio_vec *bvec;
41 struct pipe_inode_info *pipe;
44 unsigned long nr_segs;
52 static inline enum iter_type iov_iter_type(const struct iov_iter *i)
54 return i->type & ~(READ | WRITE);
57 static inline bool iter_is_iovec(const struct iov_iter *i)
59 return iov_iter_type(i) == ITER_IOVEC;
62 static inline bool iov_iter_is_kvec(const struct iov_iter *i)
64 return iov_iter_type(i) == ITER_KVEC;
67 static inline bool iov_iter_is_bvec(const struct iov_iter *i)
69 return iov_iter_type(i) == ITER_BVEC;
72 static inline bool iov_iter_is_pipe(const struct iov_iter *i)
74 return iov_iter_type(i) == ITER_PIPE;
77 static inline bool iov_iter_is_discard(const struct iov_iter *i)
79 return iov_iter_type(i) == ITER_DISCARD;
82 static inline unsigned char iov_iter_rw(const struct iov_iter *i)
84 return i->type & (READ | WRITE);
88 * Total number of bytes covered by an iovec.
90 * NOTE that it is not safe to use this function until all the iovec's
91 * segment lengths have been validated. Because the individual lengths can
92 * overflow a size_t when added together.
94 static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
99 for (seg = 0; seg < nr_segs; seg++)
100 ret += iov[seg].iov_len;
104 static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
106 return (struct iovec) {
107 .iov_base = iter->iov->iov_base + iter->iov_offset,
108 .iov_len = min(iter->count,
109 iter->iov->iov_len - iter->iov_offset),
113 #define iov_for_each(iov, iter, start) \
114 if (iov_iter_type(start) == ITER_IOVEC || \
115 iov_iter_type(start) == ITER_KVEC) \
116 for (iter = (start); \
118 ((iov = iov_iter_iovec(&(iter))), 1); \
119 iov_iter_advance(&(iter), (iov).iov_len))
121 size_t iov_iter_copy_from_user_atomic(struct page *page,
122 struct iov_iter *i, unsigned long offset, size_t bytes);
123 void iov_iter_advance(struct iov_iter *i, size_t bytes);
124 void iov_iter_revert(struct iov_iter *i, size_t bytes);
125 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
126 size_t iov_iter_single_seg_count(const struct iov_iter *i);
127 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
129 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
132 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
133 size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
134 bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
135 size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
136 bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);
138 static __always_inline __must_check
139 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
141 if (unlikely(!check_copy_size(addr, bytes, true)))
144 return _copy_to_iter(addr, bytes, i);
147 static __always_inline __must_check
148 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
150 if (unlikely(!check_copy_size(addr, bytes, false)))
153 return _copy_from_iter(addr, bytes, i);
156 static __always_inline __must_check
157 bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
159 if (unlikely(!check_copy_size(addr, bytes, false)))
162 return _copy_from_iter_full(addr, bytes, i);
165 static __always_inline __must_check
166 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
168 if (unlikely(!check_copy_size(addr, bytes, false)))
171 return _copy_from_iter_nocache(addr, bytes, i);
174 static __always_inline __must_check
175 bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
177 if (unlikely(!check_copy_size(addr, bytes, false)))
180 return _copy_from_iter_full_nocache(addr, bytes, i);
183 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
185 * Note, users like pmem that depend on the stricter semantics of
186 * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
187 * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
188 * destination is flushed from the cache on return.
190 size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i);
192 #define _copy_from_iter_flushcache _copy_from_iter_nocache
195 #ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
196 size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i);
198 #define _copy_to_iter_mcsafe _copy_to_iter
201 static __always_inline __must_check
202 size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
204 if (unlikely(!check_copy_size(addr, bytes, false)))
207 return _copy_from_iter_flushcache(addr, bytes, i);
210 static __always_inline __must_check
211 size_t copy_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i)
213 if (unlikely(!check_copy_size(addr, bytes, true)))
216 return _copy_to_iter_mcsafe(addr, bytes, i);
219 size_t iov_iter_zero(size_t bytes, struct iov_iter *);
220 unsigned long iov_iter_alignment(const struct iov_iter *i);
221 unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
222 void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov,
223 unsigned long nr_segs, size_t count);
224 void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec,
225 unsigned long nr_segs, size_t count);
226 void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec,
227 unsigned long nr_segs, size_t count);
228 void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe,
230 void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
231 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
232 size_t maxsize, unsigned maxpages, size_t *start);
233 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
234 size_t maxsize, size_t *start);
235 int iov_iter_npages(const struct iov_iter *i, int maxpages);
237 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
239 static inline size_t iov_iter_count(const struct iov_iter *i)
245 * Cap the iov_iter by given limit; note that the second argument is
246 * *not* the new size - it's upper limit for such. Passing it a value
247 * greater than the amount of data in iov_iter is fine - it'll just do
248 * nothing in that case.
250 static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
253 * count doesn't have to fit in size_t - comparison extends both
254 * operands to u64 here and any value that would be truncated by
255 * conversion in assignement is by definition greater than all
256 * values of size_t, including old i->count.
258 if (i->count > count)
263 * reexpand a previously truncated iterator; count must be no more than how much
266 static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
270 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump, struct iov_iter *i);
271 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
272 bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
273 size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
276 int import_iovec(int type, const struct iovec __user * uvector,
277 unsigned nr_segs, unsigned fast_segs,
278 struct iovec **iov, struct iov_iter *i);
282 int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
283 unsigned nr_segs, unsigned fast_segs,
284 struct iovec **iov, struct iov_iter *i);
287 int import_single_range(int type, void __user *buf, size_t len,
288 struct iovec *iov, struct iov_iter *i);
290 int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
291 int (*f)(struct kvec *vec, void *context),