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 | 15 | |
f62e52d1 DH |
16 | typedef unsigned int __bitwise iov_iter_extraction_t; |
17 | ||
812ed032 JS |
18 | struct kvec { |
19 | void *iov_base; /* and that should *never* hold a userland pointer */ | |
20 | size_t iov_len; | |
21 | }; | |
22 | ||
00e23707 | 23 | enum iter_type { |
875f1d07 | 24 | /* iter types */ |
8cd54c1c AV |
25 | ITER_IOVEC, |
26 | ITER_KVEC, | |
27 | ITER_BVEC, | |
28 | ITER_PIPE, | |
29 | ITER_XARRAY, | |
30 | ITER_DISCARD, | |
fcb14cb1 | 31 | ITER_UBUF, |
62a8067a AV |
32 | }; |
33 | ||
de4eda9d AV |
34 | #define ITER_SOURCE 1 // == WRITE |
35 | #define ITER_DEST 0 // == READ | |
36 | ||
8fb0f47a JA |
37 | struct iov_iter_state { |
38 | size_t iov_offset; | |
39 | size_t count; | |
40 | unsigned long nr_segs; | |
41 | }; | |
42 | ||
92236878 | 43 | struct iov_iter { |
8cd54c1c | 44 | u8 iter_type; |
3337ab08 | 45 | bool nofault; |
8cd54c1c | 46 | bool data_source; |
fcb14cb1 | 47 | bool user_backed; |
10f525a8 AV |
48 | union { |
49 | size_t iov_offset; | |
50 | int last_offset; | |
51 | }; | |
747b1f65 JA |
52 | /* |
53 | * Hack alert: overlay ubuf_iovec with iovec + count, so | |
54 | * that the members resolve correctly regardless of the type | |
55 | * of iterator used. This means that you can use: | |
56 | * | |
57 | * &iter->__ubuf_iovec or iter->__iov | |
58 | * | |
59 | * interchangably for the user_backed cases, hence simplifying | |
60 | * some of the cases that need to deal with both. | |
61 | */ | |
62a8067a | 62 | union { |
747b1f65 JA |
63 | /* |
64 | * This really should be a const, but we cannot do that without | |
65 | * also modifying any of the zero-filling iter init functions. | |
66 | * Leave it non-const for now, but it should be treated as such. | |
67 | */ | |
68 | struct iovec __ubuf_iovec; | |
69 | struct { | |
70 | union { | |
71 | /* use iter_iov() to get the current vec */ | |
72 | const struct iovec *__iov; | |
73 | const struct kvec *kvec; | |
74 | const struct bio_vec *bvec; | |
75 | struct xarray *xarray; | |
76 | struct pipe_inode_info *pipe; | |
77 | void __user *ubuf; | |
78 | }; | |
79 | size_t count; | |
80 | }; | |
241699cd AV |
81 | }; |
82 | union { | |
83 | unsigned long nr_segs; | |
27c0e374 | 84 | struct { |
8cefc107 DH |
85 | unsigned int head; |
86 | unsigned int start_head; | |
27c0e374 | 87 | }; |
7ff50620 | 88 | loff_t xarray_start; |
62a8067a | 89 | }; |
92236878 KO |
90 | }; |
91 | ||
747b1f65 JA |
92 | static inline const struct iovec *iter_iov(const struct iov_iter *iter) |
93 | { | |
94 | if (iter->iter_type == ITER_UBUF) | |
95 | return (const struct iovec *) &iter->__ubuf_iovec; | |
96 | return iter->__iov; | |
97 | } | |
98 | ||
95e49cf8 JA |
99 | #define iter_iov_addr(iter) (iter_iov(iter)->iov_base + (iter)->iov_offset) |
100 | #define iter_iov_len(iter) (iter_iov(iter)->iov_len - (iter)->iov_offset) | |
de4f5fed | 101 | |
00e23707 DH |
102 | static inline enum iter_type iov_iter_type(const struct iov_iter *i) |
103 | { | |
8cd54c1c | 104 | return i->iter_type; |
00e23707 DH |
105 | } |
106 | ||
8fb0f47a JA |
107 | static inline void iov_iter_save_state(struct iov_iter *iter, |
108 | struct iov_iter_state *state) | |
109 | { | |
110 | state->iov_offset = iter->iov_offset; | |
111 | state->count = iter->count; | |
112 | state->nr_segs = iter->nr_segs; | |
113 | } | |
114 | ||
fcb14cb1 AV |
115 | static inline bool iter_is_ubuf(const struct iov_iter *i) |
116 | { | |
117 | return iov_iter_type(i) == ITER_UBUF; | |
118 | } | |
119 | ||
00e23707 DH |
120 | static inline bool iter_is_iovec(const struct iov_iter *i) |
121 | { | |
122 | return iov_iter_type(i) == ITER_IOVEC; | |
123 | } | |
124 | ||
125 | static inline bool iov_iter_is_kvec(const struct iov_iter *i) | |
126 | { | |
127 | return iov_iter_type(i) == ITER_KVEC; | |
128 | } | |
129 | ||
130 | static inline bool iov_iter_is_bvec(const struct iov_iter *i) | |
131 | { | |
132 | return iov_iter_type(i) == ITER_BVEC; | |
133 | } | |
134 | ||
135 | static inline bool iov_iter_is_pipe(const struct iov_iter *i) | |
136 | { | |
137 | return iov_iter_type(i) == ITER_PIPE; | |
138 | } | |
139 | ||
9ea9ce04 DH |
140 | static inline bool iov_iter_is_discard(const struct iov_iter *i) |
141 | { | |
142 | return iov_iter_type(i) == ITER_DISCARD; | |
143 | } | |
144 | ||
7ff50620 DH |
145 | static inline bool iov_iter_is_xarray(const struct iov_iter *i) |
146 | { | |
147 | return iov_iter_type(i) == ITER_XARRAY; | |
148 | } | |
149 | ||
00e23707 DH |
150 | static inline unsigned char iov_iter_rw(const struct iov_iter *i) |
151 | { | |
8cd54c1c | 152 | return i->data_source ? WRITE : READ; |
00e23707 DH |
153 | } |
154 | ||
fcb14cb1 AV |
155 | static inline bool user_backed_iter(const struct iov_iter *i) |
156 | { | |
157 | return i->user_backed; | |
158 | } | |
159 | ||
1da177e4 LT |
160 | /* |
161 | * Total number of bytes covered by an iovec. | |
162 | * | |
163 | * NOTE that it is not safe to use this function until all the iovec's | |
164 | * segment lengths have been validated. Because the individual lengths can | |
165 | * overflow a size_t when added together. | |
166 | */ | |
167 | static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) | |
168 | { | |
169 | unsigned long seg; | |
170 | size_t ret = 0; | |
171 | ||
172 | for (seg = 0; seg < nr_segs; seg++) | |
173 | ret += iov[seg].iov_len; | |
174 | return ret; | |
175 | } | |
176 | ||
f0b65f39 AV |
177 | size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, |
178 | size_t bytes, struct iov_iter *i); | |
92236878 | 179 | void iov_iter_advance(struct iov_iter *i, size_t bytes); |
27c0e374 | 180 | void iov_iter_revert(struct iov_iter *i, size_t bytes); |
a6294593 | 181 | size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t bytes); |
cdd591fc | 182 | size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t bytes); |
92236878 | 183 | size_t iov_iter_single_seg_count(const struct iov_iter *i); |
6e58e79d AV |
184 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
185 | struct iov_iter *i); | |
f0d1bec9 AV |
186 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
187 | struct iov_iter *i); | |
aa28de27 AV |
188 | |
189 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i); | |
190 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i); | |
aa28de27 | 191 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i); |
aa28de27 | 192 | |
d9c19d32 MWO |
193 | static inline size_t copy_folio_to_iter(struct folio *folio, size_t offset, |
194 | size_t bytes, struct iov_iter *i) | |
195 | { | |
196 | return copy_page_to_iter(&folio->page, offset, bytes, i); | |
197 | } | |
198 | ||
aa28de27 AV |
199 | static __always_inline __must_check |
200 | size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) | |
201 | { | |
0e3c3b90 | 202 | if (check_copy_size(addr, bytes, true)) |
aa28de27 | 203 | return _copy_to_iter(addr, bytes, i); |
0e3c3b90 | 204 | return 0; |
aa28de27 AV |
205 | } |
206 | ||
207 | static __always_inline __must_check | |
208 | size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) | |
209 | { | |
0e3c3b90 | 210 | if (check_copy_size(addr, bytes, false)) |
aa28de27 | 211 | return _copy_from_iter(addr, bytes, i); |
0e3c3b90 | 212 | return 0; |
aa28de27 AV |
213 | } |
214 | ||
215 | static __always_inline __must_check | |
216 | bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) | |
217 | { | |
4b6c132b AV |
218 | size_t copied = copy_from_iter(addr, bytes, i); |
219 | if (likely(copied == bytes)) | |
220 | return true; | |
221 | iov_iter_revert(i, copied); | |
222 | return false; | |
aa28de27 AV |
223 | } |
224 | ||
225 | static __always_inline __must_check | |
226 | size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
227 | { | |
0e3c3b90 | 228 | if (check_copy_size(addr, bytes, false)) |
aa28de27 | 229 | return _copy_from_iter_nocache(addr, bytes, i); |
0e3c3b90 | 230 | return 0; |
aa28de27 AV |
231 | } |
232 | ||
233 | static __always_inline __must_check | |
234 | bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
235 | { | |
4b6c132b AV |
236 | size_t copied = copy_from_iter_nocache(addr, bytes, i); |
237 | if (likely(copied == bytes)) | |
238 | return true; | |
239 | iov_iter_revert(i, copied); | |
240 | return false; | |
aa28de27 AV |
241 | } |
242 | ||
0aed55af DW |
243 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
244 | /* | |
245 | * Note, users like pmem that depend on the stricter semantics of | |
e17f7a0b | 246 | * _copy_from_iter_flushcache() than _copy_from_iter_nocache() must check for |
0aed55af DW |
247 | * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the |
248 | * destination is flushed from the cache on return. | |
249 | */ | |
6a37e940 | 250 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i); |
0aed55af | 251 | #else |
6a37e940 LT |
252 | #define _copy_from_iter_flushcache _copy_from_iter_nocache |
253 | #endif | |
254 | ||
ec6347bb DW |
255 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
256 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i); | |
8780356e | 257 | #else |
ec6347bb | 258 | #define _copy_mc_to_iter _copy_to_iter |
8780356e DW |
259 | #endif |
260 | ||
c35e0248 | 261 | size_t iov_iter_zero(size_t bytes, struct iov_iter *); |
cfa320f7 KB |
262 | bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, |
263 | unsigned len_mask); | |
886a3911 | 264 | unsigned long iov_iter_alignment(const struct iov_iter *i); |
357f435d | 265 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i); |
aa563d7b | 266 | void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov, |
71d8e532 | 267 | unsigned long nr_segs, size_t count); |
aa563d7b | 268 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec, |
05afcb77 | 269 | unsigned long nr_segs, size_t count); |
aa563d7b | 270 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec, |
abb78f87 | 271 | unsigned long nr_segs, size_t count); |
aa563d7b | 272 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe, |
241699cd | 273 | size_t count); |
9ea9ce04 | 274 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count); |
7ff50620 DH |
275 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray, |
276 | loff_t start, size_t count); | |
d8207640 LG |
277 | ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, |
278 | size_t maxsize, unsigned maxpages, size_t *start, | |
f62e52d1 | 279 | iov_iter_extraction_t extraction_flags); |
eba2d3d7 | 280 | ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages, |
2c80929c | 281 | size_t maxsize, unsigned maxpages, size_t *start); |
d8207640 LG |
282 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
283 | struct page ***pages, size_t maxsize, size_t *start, | |
f62e52d1 | 284 | iov_iter_extraction_t extraction_flags); |
eba2d3d7 | 285 | ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages, |
91f79c43 | 286 | size_t maxsize, size_t *start); |
f67da30c | 287 | int iov_iter_npages(const struct iov_iter *i, int maxpages); |
8fb0f47a | 288 | void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state); |
92236878 | 289 | |
4b8164b9 AV |
290 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags); |
291 | ||
b57332b4 | 292 | static inline size_t iov_iter_count(const struct iov_iter *i) |
92236878 KO |
293 | { |
294 | return i->count; | |
295 | } | |
296 | ||
0b86dbf6 AV |
297 | /* |
298 | * Cap the iov_iter by given limit; note that the second argument is | |
299 | * *not* the new size - it's upper limit for such. Passing it a value | |
300 | * greater than the amount of data in iov_iter is fine - it'll just do | |
301 | * nothing in that case. | |
302 | */ | |
303 | static inline void iov_iter_truncate(struct iov_iter *i, u64 count) | |
0c949334 | 304 | { |
0b86dbf6 AV |
305 | /* |
306 | * count doesn't have to fit in size_t - comparison extends both | |
307 | * operands to u64 here and any value that would be truncated by | |
308 | * conversion in assignement is by definition greater than all | |
309 | * values of size_t, including old i->count. | |
310 | */ | |
7dedd3e1 | 311 | if (i->count > count) |
0c949334 AV |
312 | i->count = count; |
313 | } | |
314 | ||
b42b15fd AV |
315 | /* |
316 | * reexpand a previously truncated iterator; count must be no more than how much | |
317 | * we had shrunk it. | |
318 | */ | |
319 | static inline void iov_iter_reexpand(struct iov_iter *i, size_t count) | |
320 | { | |
321 | i->count = count; | |
322 | } | |
52cbd23a | 323 | |
b93235e6 JK |
324 | static inline int |
325 | iov_iter_npages_cap(struct iov_iter *i, int maxpages, size_t max_bytes) | |
326 | { | |
327 | size_t shorted = 0; | |
328 | int npages; | |
329 | ||
330 | if (iov_iter_count(i) > max_bytes) { | |
331 | shorted = iov_iter_count(i) - max_bytes; | |
332 | iov_iter_truncate(i, max_bytes); | |
333 | } | |
7187440d | 334 | npages = iov_iter_npages(i, maxpages); |
b93235e6 JK |
335 | if (shorted) |
336 | iov_iter_reexpand(i, iov_iter_count(i) + shorted); | |
337 | ||
338 | return npages; | |
339 | } | |
340 | ||
52cbd23a WB |
341 | struct csum_state { |
342 | __wsum csum; | |
343 | size_t off; | |
344 | }; | |
345 | ||
346 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i); | |
a604ec7e | 347 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i); |
4b6c132b AV |
348 | |
349 | static __always_inline __must_check | |
350 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, | |
351 | __wsum *csum, struct iov_iter *i) | |
352 | { | |
353 | size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i); | |
354 | if (likely(copied == bytes)) | |
355 | return true; | |
356 | iov_iter_revert(i, copied); | |
357 | return false; | |
358 | } | |
d05f4435 SG |
359 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
360 | struct iov_iter *i); | |
b42b15fd | 361 | |
bfdc5970 CH |
362 | struct iovec *iovec_from_user(const struct iovec __user *uvector, |
363 | unsigned long nr_segs, unsigned long fast_segs, | |
364 | struct iovec *fast_iov, bool compat); | |
365 | ssize_t import_iovec(int type, const struct iovec __user *uvec, | |
366 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
367 | struct iov_iter *i); | |
368 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
369 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
370 | struct iov_iter *i, bool compat); | |
bc917be8 AV |
371 | int import_single_range(int type, void __user *buf, size_t len, |
372 | struct iovec *iov, struct iov_iter *i); | |
2ad9bd83 | 373 | int import_ubuf(int type, void __user *buf, size_t len, struct iov_iter *i); |
bc917be8 | 374 | |
fcb14cb1 AV |
375 | static inline void iov_iter_ubuf(struct iov_iter *i, unsigned int direction, |
376 | void __user *buf, size_t count) | |
377 | { | |
378 | WARN_ON(direction & ~(READ | WRITE)); | |
379 | *i = (struct iov_iter) { | |
380 | .iter_type = ITER_UBUF, | |
381 | .user_backed = true, | |
382 | .data_source = direction, | |
383 | .ubuf = buf, | |
cd0bd57a JA |
384 | .count = count, |
385 | .nr_segs = 1 | |
fcb14cb1 AV |
386 | }; |
387 | } | |
f62e52d1 DH |
388 | /* Flags for iov_iter_get/extract_pages*() */ |
389 | /* Allow P2PDMA on the extracted pages */ | |
390 | #define ITER_ALLOW_P2PDMA ((__force iov_iter_extraction_t)0x01) | |
391 | ||
7d58fe73 DH |
392 | ssize_t iov_iter_extract_pages(struct iov_iter *i, struct page ***pages, |
393 | size_t maxsize, unsigned int maxpages, | |
394 | iov_iter_extraction_t extraction_flags, | |
395 | size_t *offset0); | |
396 | ||
397 | /** | |
398 | * iov_iter_extract_will_pin - Indicate how pages from the iterator will be retained | |
399 | * @iter: The iterator | |
400 | * | |
401 | * Examine the iterator and indicate by returning true or false as to how, if | |
402 | * at all, pages extracted from the iterator will be retained by the extraction | |
403 | * function. | |
404 | * | |
405 | * %true indicates that the pages will have a pin placed in them that the | |
406 | * caller must unpin. This is must be done for DMA/async DIO to force fork() | |
407 | * to forcibly copy a page for the child (the parent must retain the original | |
408 | * page). | |
409 | * | |
410 | * %false indicates that no measures are taken and that it's up to the caller | |
411 | * to retain the pages. | |
412 | */ | |
413 | static inline bool iov_iter_extract_will_pin(const struct iov_iter *iter) | |
414 | { | |
415 | return user_backed_iter(iter); | |
416 | } | |
fcb14cb1 | 417 | |
812ed032 | 418 | #endif |