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 <uapi/linux/uio.h>
13 struct pipe_inode_info;
16 void *iov_base; /* and that should *never* hold a userland pointer */
30 struct iov_iter_state {
33 unsigned long nr_segs;
42 const struct iovec *iov;
43 const struct kvec *kvec;
44 const struct bio_vec *bvec;
45 struct xarray *xarray;
46 struct pipe_inode_info *pipe;
49 unsigned long nr_segs;
52 unsigned int start_head;
58 static inline enum iter_type iov_iter_type(const struct iov_iter *i)
63 static inline void iov_iter_save_state(struct iov_iter *iter,
64 struct iov_iter_state *state)
66 state->iov_offset = iter->iov_offset;
67 state->count = iter->count;
68 state->nr_segs = iter->nr_segs;
71 static inline bool iter_is_iovec(const struct iov_iter *i)
73 return iov_iter_type(i) == ITER_IOVEC;
76 static inline bool iov_iter_is_kvec(const struct iov_iter *i)
78 return iov_iter_type(i) == ITER_KVEC;
81 static inline bool iov_iter_is_bvec(const struct iov_iter *i)
83 return iov_iter_type(i) == ITER_BVEC;
86 static inline bool iov_iter_is_pipe(const struct iov_iter *i)
88 return iov_iter_type(i) == ITER_PIPE;
91 static inline bool iov_iter_is_discard(const struct iov_iter *i)
93 return iov_iter_type(i) == ITER_DISCARD;
96 static inline bool iov_iter_is_xarray(const struct iov_iter *i)
98 return iov_iter_type(i) == ITER_XARRAY;
101 static inline unsigned char iov_iter_rw(const struct iov_iter *i)
103 return i->data_source ? WRITE : READ;
107 * Total number of bytes covered by an iovec.
109 * NOTE that it is not safe to use this function until all the iovec's
110 * segment lengths have been validated. Because the individual lengths can
111 * overflow a size_t when added together.
113 static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
118 for (seg = 0; seg < nr_segs; seg++)
119 ret += iov[seg].iov_len;
123 static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
125 return (struct iovec) {
126 .iov_base = iter->iov->iov_base + iter->iov_offset,
127 .iov_len = min(iter->count,
128 iter->iov->iov_len - iter->iov_offset),
132 size_t copy_page_from_iter_atomic(struct page *page, unsigned offset,
133 size_t bytes, struct iov_iter *i);
134 void iov_iter_advance(struct iov_iter *i, size_t bytes);
135 void iov_iter_revert(struct iov_iter *i, size_t bytes);
136 int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes);
137 size_t iov_iter_single_seg_count(const struct iov_iter *i);
138 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
140 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
143 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
144 size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
145 size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
147 static __always_inline __must_check
148 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
150 if (unlikely(!check_copy_size(addr, bytes, true)))
153 return _copy_to_iter(addr, bytes, i);
156 static __always_inline __must_check
157 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
159 if (unlikely(!check_copy_size(addr, bytes, false)))
162 return _copy_from_iter(addr, bytes, i);
165 static __always_inline __must_check
166 bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
168 size_t copied = copy_from_iter(addr, bytes, i);
169 if (likely(copied == bytes))
171 iov_iter_revert(i, copied);
175 static __always_inline __must_check
176 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
178 if (unlikely(!check_copy_size(addr, bytes, false)))
181 return _copy_from_iter_nocache(addr, bytes, i);
184 static __always_inline __must_check
185 bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
187 size_t copied = copy_from_iter_nocache(addr, bytes, i);
188 if (likely(copied == bytes))
190 iov_iter_revert(i, copied);
194 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
196 * Note, users like pmem that depend on the stricter semantics of
197 * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
198 * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
199 * destination is flushed from the cache on return.
201 size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i);
203 #define _copy_from_iter_flushcache _copy_from_iter_nocache
206 #ifdef CONFIG_ARCH_HAS_COPY_MC
207 size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
209 #define _copy_mc_to_iter _copy_to_iter
212 static __always_inline __must_check
213 size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
215 if (unlikely(!check_copy_size(addr, bytes, false)))
218 return _copy_from_iter_flushcache(addr, bytes, i);
221 static __always_inline __must_check
222 size_t copy_mc_to_iter(void *addr, size_t bytes, struct iov_iter *i)
224 if (unlikely(!check_copy_size(addr, bytes, true)))
227 return _copy_mc_to_iter(addr, bytes, i);
230 size_t iov_iter_zero(size_t bytes, struct iov_iter *);
231 unsigned long iov_iter_alignment(const struct iov_iter *i);
232 unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
233 void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov,
234 unsigned long nr_segs, size_t count);
235 void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec,
236 unsigned long nr_segs, size_t count);
237 void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec,
238 unsigned long nr_segs, size_t count);
239 void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe,
241 void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
242 void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray,
243 loff_t start, size_t count);
244 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
245 size_t maxsize, unsigned maxpages, size_t *start);
246 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
247 size_t maxsize, size_t *start);
248 int iov_iter_npages(const struct iov_iter *i, int maxpages);
249 void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state);
251 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
253 static inline size_t iov_iter_count(const struct iov_iter *i)
259 * Cap the iov_iter by given limit; note that the second argument is
260 * *not* the new size - it's upper limit for such. Passing it a value
261 * greater than the amount of data in iov_iter is fine - it'll just do
262 * nothing in that case.
264 static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
267 * count doesn't have to fit in size_t - comparison extends both
268 * operands to u64 here and any value that would be truncated by
269 * conversion in assignement is by definition greater than all
270 * values of size_t, including old i->count.
272 if (i->count > count)
277 * reexpand a previously truncated iterator; count must be no more than how much
280 static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
290 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i);
291 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
293 static __always_inline __must_check
294 bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
295 __wsum *csum, struct iov_iter *i)
297 size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i);
298 if (likely(copied == bytes))
300 iov_iter_revert(i, copied);
303 size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
306 struct iovec *iovec_from_user(const struct iovec __user *uvector,
307 unsigned long nr_segs, unsigned long fast_segs,
308 struct iovec *fast_iov, bool compat);
309 ssize_t import_iovec(int type, const struct iovec __user *uvec,
310 unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
312 ssize_t __import_iovec(int type, const struct iovec __user *uvec,
313 unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
314 struct iov_iter *i, bool compat);
315 int import_single_range(int type, void __user *buf, size_t len,
316 struct iovec *iov, struct iov_iter *i);