Commit | Line | Data |
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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
1da177e4 LT |
2 | /* |
3 | * Berkeley style UIO structures - Alan Cox 1994. | |
1da177e4 | 4 | */ |
607ca46e DH |
5 | #ifndef __LINUX_UIO_H |
6 | #define __LINUX_UIO_H | |
1da177e4 | 7 | |
92236878 | 8 | #include <linux/kernel.h> |
aa28de27 | 9 | #include <linux/thread_info.h> |
d9c19d32 | 10 | #include <linux/mm_types.h> |
607ca46e | 11 | #include <uapi/linux/uio.h> |
1da177e4 | 12 | |
92236878 | 13 | struct page; |
241699cd | 14 | struct pipe_inode_info; |
812ed032 JS |
15 | |
16 | struct kvec { | |
17 | void *iov_base; /* and that should *never* hold a userland pointer */ | |
18 | size_t iov_len; | |
19 | }; | |
20 | ||
00e23707 | 21 | enum iter_type { |
875f1d07 | 22 | /* iter types */ |
8cd54c1c AV |
23 | ITER_IOVEC, |
24 | ITER_KVEC, | |
25 | ITER_BVEC, | |
26 | ITER_PIPE, | |
27 | ITER_XARRAY, | |
28 | ITER_DISCARD, | |
62a8067a AV |
29 | }; |
30 | ||
8fb0f47a JA |
31 | struct iov_iter_state { |
32 | size_t iov_offset; | |
33 | size_t count; | |
34 | unsigned long nr_segs; | |
35 | }; | |
36 | ||
92236878 | 37 | struct iov_iter { |
8cd54c1c | 38 | u8 iter_type; |
3337ab08 | 39 | bool nofault; |
8cd54c1c | 40 | bool data_source; |
92236878 KO |
41 | size_t iov_offset; |
42 | size_t count; | |
62a8067a AV |
43 | union { |
44 | const struct iovec *iov; | |
a280455f | 45 | const struct kvec *kvec; |
62a8067a | 46 | const struct bio_vec *bvec; |
7ff50620 | 47 | struct xarray *xarray; |
241699cd AV |
48 | struct pipe_inode_info *pipe; |
49 | }; | |
50 | union { | |
51 | unsigned long nr_segs; | |
27c0e374 | 52 | struct { |
8cefc107 DH |
53 | unsigned int head; |
54 | unsigned int start_head; | |
27c0e374 | 55 | }; |
7ff50620 | 56 | loff_t xarray_start; |
62a8067a | 57 | }; |
92236878 KO |
58 | }; |
59 | ||
00e23707 DH |
60 | static inline enum iter_type iov_iter_type(const struct iov_iter *i) |
61 | { | |
8cd54c1c | 62 | return i->iter_type; |
00e23707 DH |
63 | } |
64 | ||
8fb0f47a JA |
65 | static inline void iov_iter_save_state(struct iov_iter *iter, |
66 | struct iov_iter_state *state) | |
67 | { | |
68 | state->iov_offset = iter->iov_offset; | |
69 | state->count = iter->count; | |
70 | state->nr_segs = iter->nr_segs; | |
71 | } | |
72 | ||
00e23707 DH |
73 | static inline bool iter_is_iovec(const struct iov_iter *i) |
74 | { | |
75 | return iov_iter_type(i) == ITER_IOVEC; | |
76 | } | |
77 | ||
78 | static inline bool iov_iter_is_kvec(const struct iov_iter *i) | |
79 | { | |
80 | return iov_iter_type(i) == ITER_KVEC; | |
81 | } | |
82 | ||
83 | static inline bool iov_iter_is_bvec(const struct iov_iter *i) | |
84 | { | |
85 | return iov_iter_type(i) == ITER_BVEC; | |
86 | } | |
87 | ||
88 | static inline bool iov_iter_is_pipe(const struct iov_iter *i) | |
89 | { | |
90 | return iov_iter_type(i) == ITER_PIPE; | |
91 | } | |
92 | ||
9ea9ce04 DH |
93 | static inline bool iov_iter_is_discard(const struct iov_iter *i) |
94 | { | |
95 | return iov_iter_type(i) == ITER_DISCARD; | |
96 | } | |
97 | ||
7ff50620 DH |
98 | static inline bool iov_iter_is_xarray(const struct iov_iter *i) |
99 | { | |
100 | return iov_iter_type(i) == ITER_XARRAY; | |
101 | } | |
102 | ||
00e23707 DH |
103 | static inline unsigned char iov_iter_rw(const struct iov_iter *i) |
104 | { | |
8cd54c1c | 105 | return i->data_source ? WRITE : READ; |
00e23707 DH |
106 | } |
107 | ||
1da177e4 LT |
108 | /* |
109 | * Total number of bytes covered by an iovec. | |
110 | * | |
111 | * NOTE that it is not safe to use this function until all the iovec's | |
112 | * segment lengths have been validated. Because the individual lengths can | |
113 | * overflow a size_t when added together. | |
114 | */ | |
115 | static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) | |
116 | { | |
117 | unsigned long seg; | |
118 | size_t ret = 0; | |
119 | ||
120 | for (seg = 0; seg < nr_segs; seg++) | |
121 | ret += iov[seg].iov_len; | |
122 | return ret; | |
123 | } | |
124 | ||
92236878 KO |
125 | static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) |
126 | { | |
127 | return (struct iovec) { | |
128 | .iov_base = iter->iov->iov_base + iter->iov_offset, | |
129 | .iov_len = min(iter->count, | |
130 | iter->iov->iov_len - iter->iov_offset), | |
131 | }; | |
132 | } | |
133 | ||
f0b65f39 AV |
134 | size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, |
135 | size_t bytes, struct iov_iter *i); | |
92236878 | 136 | void iov_iter_advance(struct iov_iter *i, size_t bytes); |
27c0e374 | 137 | void iov_iter_revert(struct iov_iter *i, size_t bytes); |
a6294593 | 138 | size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t bytes); |
cdd591fc | 139 | size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t bytes); |
92236878 | 140 | size_t iov_iter_single_seg_count(const struct iov_iter *i); |
6e58e79d AV |
141 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
142 | struct iov_iter *i); | |
f0d1bec9 AV |
143 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
144 | struct iov_iter *i); | |
aa28de27 AV |
145 | |
146 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i); | |
147 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i); | |
aa28de27 | 148 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i); |
aa28de27 | 149 | |
d9c19d32 MWO |
150 | static inline size_t copy_folio_to_iter(struct folio *folio, size_t offset, |
151 | size_t bytes, struct iov_iter *i) | |
152 | { | |
153 | return copy_page_to_iter(&folio->page, offset, bytes, i); | |
154 | } | |
155 | ||
aa28de27 AV |
156 | static __always_inline __must_check |
157 | size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) | |
158 | { | |
159 | if (unlikely(!check_copy_size(addr, bytes, true))) | |
c43aeb19 | 160 | return 0; |
aa28de27 AV |
161 | else |
162 | return _copy_to_iter(addr, bytes, i); | |
163 | } | |
164 | ||
165 | static __always_inline __must_check | |
166 | size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) | |
167 | { | |
168 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
c43aeb19 | 169 | return 0; |
aa28de27 AV |
170 | else |
171 | return _copy_from_iter(addr, bytes, i); | |
172 | } | |
173 | ||
174 | static __always_inline __must_check | |
175 | bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) | |
176 | { | |
4b6c132b AV |
177 | size_t copied = copy_from_iter(addr, bytes, i); |
178 | if (likely(copied == bytes)) | |
179 | return true; | |
180 | iov_iter_revert(i, copied); | |
181 | return false; | |
aa28de27 AV |
182 | } |
183 | ||
184 | static __always_inline __must_check | |
185 | size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
186 | { | |
187 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
c43aeb19 | 188 | return 0; |
aa28de27 AV |
189 | else |
190 | return _copy_from_iter_nocache(addr, bytes, i); | |
191 | } | |
192 | ||
193 | static __always_inline __must_check | |
194 | bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
195 | { | |
4b6c132b AV |
196 | size_t copied = copy_from_iter_nocache(addr, bytes, i); |
197 | if (likely(copied == bytes)) | |
198 | return true; | |
199 | iov_iter_revert(i, copied); | |
200 | return false; | |
aa28de27 AV |
201 | } |
202 | ||
0aed55af DW |
203 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
204 | /* | |
205 | * Note, users like pmem that depend on the stricter semantics of | |
e17f7a0b | 206 | * _copy_from_iter_flushcache() than _copy_from_iter_nocache() must check for |
0aed55af DW |
207 | * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the |
208 | * destination is flushed from the cache on return. | |
209 | */ | |
6a37e940 | 210 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i); |
0aed55af | 211 | #else |
6a37e940 LT |
212 | #define _copy_from_iter_flushcache _copy_from_iter_nocache |
213 | #endif | |
214 | ||
ec6347bb DW |
215 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
216 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i); | |
8780356e | 217 | #else |
ec6347bb | 218 | #define _copy_mc_to_iter _copy_to_iter |
8780356e DW |
219 | #endif |
220 | ||
c35e0248 | 221 | size_t iov_iter_zero(size_t bytes, struct iov_iter *); |
886a3911 | 222 | unsigned long iov_iter_alignment(const struct iov_iter *i); |
357f435d | 223 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i); |
aa563d7b | 224 | void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov, |
71d8e532 | 225 | unsigned long nr_segs, size_t count); |
aa563d7b | 226 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec, |
05afcb77 | 227 | unsigned long nr_segs, size_t count); |
aa563d7b | 228 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec, |
abb78f87 | 229 | unsigned long nr_segs, size_t count); |
aa563d7b | 230 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe, |
241699cd | 231 | size_t count); |
9ea9ce04 | 232 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count); |
7ff50620 DH |
233 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray, |
234 | loff_t start, size_t count); | |
7b2c99d1 | 235 | ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, |
2c80929c | 236 | size_t maxsize, unsigned maxpages, size_t *start); |
91f79c43 AV |
237 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, |
238 | size_t maxsize, size_t *start); | |
f67da30c | 239 | int iov_iter_npages(const struct iov_iter *i, int maxpages); |
8fb0f47a | 240 | void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state); |
92236878 | 241 | |
4b8164b9 AV |
242 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags); |
243 | ||
b57332b4 | 244 | static inline size_t iov_iter_count(const struct iov_iter *i) |
92236878 KO |
245 | { |
246 | return i->count; | |
247 | } | |
248 | ||
0b86dbf6 AV |
249 | /* |
250 | * Cap the iov_iter by given limit; note that the second argument is | |
251 | * *not* the new size - it's upper limit for such. Passing it a value | |
252 | * greater than the amount of data in iov_iter is fine - it'll just do | |
253 | * nothing in that case. | |
254 | */ | |
255 | static inline void iov_iter_truncate(struct iov_iter *i, u64 count) | |
0c949334 | 256 | { |
0b86dbf6 AV |
257 | /* |
258 | * count doesn't have to fit in size_t - comparison extends both | |
259 | * operands to u64 here and any value that would be truncated by | |
260 | * conversion in assignement is by definition greater than all | |
261 | * values of size_t, including old i->count. | |
262 | */ | |
7dedd3e1 | 263 | if (i->count > count) |
0c949334 AV |
264 | i->count = count; |
265 | } | |
266 | ||
b42b15fd AV |
267 | /* |
268 | * reexpand a previously truncated iterator; count must be no more than how much | |
269 | * we had shrunk it. | |
270 | */ | |
271 | static inline void iov_iter_reexpand(struct iov_iter *i, size_t count) | |
272 | { | |
273 | i->count = count; | |
274 | } | |
52cbd23a | 275 | |
b93235e6 JK |
276 | static inline int |
277 | iov_iter_npages_cap(struct iov_iter *i, int maxpages, size_t max_bytes) | |
278 | { | |
279 | size_t shorted = 0; | |
280 | int npages; | |
281 | ||
282 | if (iov_iter_count(i) > max_bytes) { | |
283 | shorted = iov_iter_count(i) - max_bytes; | |
284 | iov_iter_truncate(i, max_bytes); | |
285 | } | |
286 | npages = iov_iter_npages(i, INT_MAX); | |
287 | if (shorted) | |
288 | iov_iter_reexpand(i, iov_iter_count(i) + shorted); | |
289 | ||
290 | return npages; | |
291 | } | |
292 | ||
52cbd23a WB |
293 | struct csum_state { |
294 | __wsum csum; | |
295 | size_t off; | |
296 | }; | |
297 | ||
298 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i); | |
a604ec7e | 299 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i); |
4b6c132b AV |
300 | |
301 | static __always_inline __must_check | |
302 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, | |
303 | __wsum *csum, struct iov_iter *i) | |
304 | { | |
305 | size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i); | |
306 | if (likely(copied == bytes)) | |
307 | return true; | |
308 | iov_iter_revert(i, copied); | |
309 | return false; | |
310 | } | |
d05f4435 SG |
311 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
312 | struct iov_iter *i); | |
b42b15fd | 313 | |
bfdc5970 CH |
314 | struct iovec *iovec_from_user(const struct iovec __user *uvector, |
315 | unsigned long nr_segs, unsigned long fast_segs, | |
316 | struct iovec *fast_iov, bool compat); | |
317 | ssize_t import_iovec(int type, const struct iovec __user *uvec, | |
318 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
319 | struct iov_iter *i); | |
320 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
321 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
322 | struct iov_iter *i, bool compat); | |
bc917be8 AV |
323 | int import_single_range(int type, void __user *buf, size_t len, |
324 | struct iovec *iov, struct iov_iter *i); | |
325 | ||
812ed032 | 326 | #endif |