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 */
29 struct iov_iter_state {
32 unsigned long nr_segs;
37 * Bit 0 is the read/write bit, set if we're writing.
38 * Bit 1 is the BVEC_FLAG_NO_REF bit, set if type is a bvec and
39 * the caller isn't expecting to drop a page reference when done.
45 const struct iovec *iov;
46 const struct kvec *kvec;
47 const struct bio_vec *bvec;
48 struct pipe_inode_info *pipe;
51 unsigned long nr_segs;
54 unsigned int start_head;
59 static inline enum iter_type iov_iter_type(const struct iov_iter *i)
61 return i->type & ~(READ | WRITE);
64 static inline void iov_iter_save_state(struct iov_iter *iter,
65 struct iov_iter_state *state)
67 state->iov_offset = iter->iov_offset;
68 state->count = iter->count;
69 state->nr_segs = iter->nr_segs;
72 static inline bool iter_is_iovec(const struct iov_iter *i)
74 return iov_iter_type(i) == ITER_IOVEC;
77 static inline bool iov_iter_is_kvec(const struct iov_iter *i)
79 return iov_iter_type(i) == ITER_KVEC;
82 static inline bool iov_iter_is_bvec(const struct iov_iter *i)
84 return iov_iter_type(i) == ITER_BVEC;
87 static inline bool iov_iter_is_pipe(const struct iov_iter *i)
89 return iov_iter_type(i) == ITER_PIPE;
92 static inline bool iov_iter_is_discard(const struct iov_iter *i)
94 return iov_iter_type(i) == ITER_DISCARD;
97 static inline unsigned char iov_iter_rw(const struct iov_iter *i)
99 return i->type & (READ | WRITE);
103 * Total number of bytes covered by an iovec.
105 * NOTE that it is not safe to use this function until all the iovec's
106 * segment lengths have been validated. Because the individual lengths can
107 * overflow a size_t when added together.
109 static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
114 for (seg = 0; seg < nr_segs; seg++)
115 ret += iov[seg].iov_len;
119 static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
121 return (struct iovec) {
122 .iov_base = iter->iov->iov_base + iter->iov_offset,
123 .iov_len = min(iter->count,
124 iter->iov->iov_len - iter->iov_offset),
128 size_t iov_iter_copy_from_user_atomic(struct page *page,
129 struct iov_iter *i, unsigned long offset, size_t bytes);
130 void iov_iter_advance(struct iov_iter *i, size_t bytes);
131 void iov_iter_revert(struct iov_iter *i, size_t bytes);
132 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
133 size_t iov_iter_single_seg_count(const struct iov_iter *i);
134 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
136 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
139 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
140 size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
141 bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
142 size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
143 bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);
145 static __always_inline __must_check
146 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
148 if (unlikely(!check_copy_size(addr, bytes, true)))
151 return _copy_to_iter(addr, bytes, i);
154 static __always_inline __must_check
155 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
157 if (unlikely(!check_copy_size(addr, bytes, false)))
160 return _copy_from_iter(addr, bytes, i);
163 static __always_inline __must_check
164 bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
166 if (unlikely(!check_copy_size(addr, bytes, false)))
169 return _copy_from_iter_full(addr, bytes, i);
172 static __always_inline __must_check
173 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
175 if (unlikely(!check_copy_size(addr, bytes, false)))
178 return _copy_from_iter_nocache(addr, bytes, i);
181 static __always_inline __must_check
182 bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
184 if (unlikely(!check_copy_size(addr, bytes, false)))
187 return _copy_from_iter_full_nocache(addr, bytes, i);
190 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
192 * Note, users like pmem that depend on the stricter semantics of
193 * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
194 * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
195 * destination is flushed from the cache on return.
197 size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i);
199 #define _copy_from_iter_flushcache _copy_from_iter_nocache
202 #ifdef CONFIG_ARCH_HAS_COPY_MC
203 size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
205 #define _copy_mc_to_iter _copy_to_iter
208 static __always_inline __must_check
209 size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
211 if (unlikely(!check_copy_size(addr, bytes, false)))
214 return _copy_from_iter_flushcache(addr, bytes, i);
217 static __always_inline __must_check
218 size_t copy_mc_to_iter(void *addr, size_t bytes, struct iov_iter *i)
220 if (unlikely(!check_copy_size(addr, bytes, true)))
223 return _copy_mc_to_iter(addr, bytes, i);
226 size_t iov_iter_zero(size_t bytes, struct iov_iter *);
227 unsigned long iov_iter_alignment(const struct iov_iter *i);
228 unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
229 void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov,
230 unsigned long nr_segs, size_t count);
231 void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec,
232 unsigned long nr_segs, size_t count);
233 void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec,
234 unsigned long nr_segs, size_t count);
235 void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe,
237 void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
238 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
239 size_t maxsize, unsigned maxpages, size_t *start);
240 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
241 size_t maxsize, size_t *start);
242 int iov_iter_npages(const struct iov_iter *i, int maxpages);
243 void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state);
245 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
247 static inline size_t iov_iter_count(const struct iov_iter *i)
253 * Cap the iov_iter by given limit; note that the second argument is
254 * *not* the new size - it's upper limit for such. Passing it a value
255 * greater than the amount of data in iov_iter is fine - it'll just do
256 * nothing in that case.
258 static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
261 * count doesn't have to fit in size_t - comparison extends both
262 * operands to u64 here and any value that would be truncated by
263 * conversion in assignement is by definition greater than all
264 * values of size_t, including old i->count.
266 if (i->count > count)
271 * reexpand a previously truncated iterator; count must be no more than how much
274 static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
284 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i);
285 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
286 bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
287 size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
290 struct iovec *iovec_from_user(const struct iovec __user *uvector,
291 unsigned long nr_segs, unsigned long fast_segs,
292 struct iovec *fast_iov, bool compat);
293 ssize_t import_iovec(int type, const struct iovec __user *uvec,
294 unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
296 ssize_t __import_iovec(int type, const struct iovec __user *uvec,
297 unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
298 struct iov_iter *i, bool compat);
299 int import_single_range(int type, void __user *buf, size_t len,
300 struct iovec *iov, struct iov_iter *i);
302 int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
303 int (*f)(struct kvec *vec, void *context),