1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Berkeley style UIO structures - Alan Cox 1994.
8 #include <linux/kernel.h>
9 #include <linux/thread_info.h>
10 #include <crypto/hash.h>
11 #include <uapi/linux/uio.h>
14 struct pipe_inode_info;
17 void *iov_base; /* and that should *never* hold a userland pointer */
32 * Bit 0 is the read/write bit, set if we're writing.
33 * Bit 1 is the BVEC_FLAG_NO_REF bit, set if type is a bvec and
34 * the caller isn't expecting to drop a page reference when done.
40 const struct iovec *iov;
41 const struct kvec *kvec;
42 const struct bio_vec *bvec;
43 struct pipe_inode_info *pipe;
46 unsigned long nr_segs;
49 unsigned int start_head;
54 static inline enum iter_type iov_iter_type(const struct iov_iter *i)
56 return i->type & ~(READ | WRITE);
59 static inline bool iter_is_iovec(const struct iov_iter *i)
61 return iov_iter_type(i) == ITER_IOVEC;
64 static inline bool iov_iter_is_kvec(const struct iov_iter *i)
66 return iov_iter_type(i) == ITER_KVEC;
69 static inline bool iov_iter_is_bvec(const struct iov_iter *i)
71 return iov_iter_type(i) == ITER_BVEC;
74 static inline bool iov_iter_is_pipe(const struct iov_iter *i)
76 return iov_iter_type(i) == ITER_PIPE;
79 static inline bool iov_iter_is_discard(const struct iov_iter *i)
81 return iov_iter_type(i) == ITER_DISCARD;
84 static inline unsigned char iov_iter_rw(const struct iov_iter *i)
86 return i->type & (READ | WRITE);
90 * Total number of bytes covered by an iovec.
92 * NOTE that it is not safe to use this function until all the iovec's
93 * segment lengths have been validated. Because the individual lengths can
94 * overflow a size_t when added together.
96 static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
101 for (seg = 0; seg < nr_segs; seg++)
102 ret += iov[seg].iov_len;
106 static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
108 return (struct iovec) {
109 .iov_base = iter->iov->iov_base + iter->iov_offset,
110 .iov_len = min(iter->count,
111 iter->iov->iov_len - iter->iov_offset),
115 size_t iov_iter_copy_from_user_atomic(struct page *page,
116 struct iov_iter *i, unsigned long offset, size_t bytes);
117 void iov_iter_advance(struct iov_iter *i, size_t bytes);
118 void iov_iter_revert(struct iov_iter *i, size_t bytes);
119 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
120 size_t iov_iter_single_seg_count(const struct iov_iter *i);
121 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
123 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
126 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
127 size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
128 bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
129 size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
130 bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);
132 static __always_inline __must_check
133 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
135 if (unlikely(!check_copy_size(addr, bytes, true)))
138 return _copy_to_iter(addr, bytes, i);
141 static __always_inline __must_check
142 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
144 if (unlikely(!check_copy_size(addr, bytes, false)))
147 return _copy_from_iter(addr, bytes, i);
150 static __always_inline __must_check
151 bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
153 if (unlikely(!check_copy_size(addr, bytes, false)))
156 return _copy_from_iter_full(addr, bytes, i);
159 static __always_inline __must_check
160 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
162 if (unlikely(!check_copy_size(addr, bytes, false)))
165 return _copy_from_iter_nocache(addr, bytes, i);
168 static __always_inline __must_check
169 bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
171 if (unlikely(!check_copy_size(addr, bytes, false)))
174 return _copy_from_iter_full_nocache(addr, bytes, i);
177 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
179 * Note, users like pmem that depend on the stricter semantics of
180 * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
181 * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
182 * destination is flushed from the cache on return.
184 size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i);
186 #define _copy_from_iter_flushcache _copy_from_iter_nocache
189 #ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
190 size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i);
192 #define _copy_to_iter_mcsafe _copy_to_iter
195 static __always_inline __must_check
196 size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
198 if (unlikely(!check_copy_size(addr, bytes, false)))
201 return _copy_from_iter_flushcache(addr, bytes, i);
204 static __always_inline __must_check
205 size_t copy_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i)
207 if (unlikely(!check_copy_size(addr, bytes, true)))
210 return _copy_to_iter_mcsafe(addr, bytes, i);
213 size_t iov_iter_zero(size_t bytes, struct iov_iter *);
214 unsigned long iov_iter_alignment(const struct iov_iter *i);
215 unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
216 void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov,
217 unsigned long nr_segs, size_t count);
218 void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec,
219 unsigned long nr_segs, size_t count);
220 void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec,
221 unsigned long nr_segs, size_t count);
222 void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe,
224 void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
225 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
226 size_t maxsize, unsigned maxpages, size_t *start);
227 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
228 size_t maxsize, size_t *start);
229 int iov_iter_npages(const struct iov_iter *i, int maxpages);
231 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
233 static inline size_t iov_iter_count(const struct iov_iter *i)
239 * Cap the iov_iter by given limit; note that the second argument is
240 * *not* the new size - it's upper limit for such. Passing it a value
241 * greater than the amount of data in iov_iter is fine - it'll just do
242 * nothing in that case.
244 static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
247 * count doesn't have to fit in size_t - comparison extends both
248 * operands to u64 here and any value that would be truncated by
249 * conversion in assignement is by definition greater than all
250 * values of size_t, including old i->count.
252 if (i->count > count)
257 * reexpand a previously truncated iterator; count must be no more than how much
260 static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
264 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump, struct iov_iter *i);
265 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
266 bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
267 size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
270 ssize_t import_iovec(int type, const struct iovec __user * uvector,
271 unsigned nr_segs, unsigned fast_segs,
272 struct iovec **iov, struct iov_iter *i);
276 ssize_t compat_import_iovec(int type, const struct compat_iovec __user * uvector,
277 unsigned nr_segs, unsigned fast_segs,
278 struct iovec **iov, struct iov_iter *i);
281 int import_single_range(int type, void __user *buf, size_t len,
282 struct iovec *iov, struct iov_iter *i);
284 int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
285 int (*f)(struct kvec *vec, void *context),