Commit | Line | Data |
---|---|---|
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 | }; | |
92236878 | 52 | size_t count; |
62a8067a | 53 | union { |
de4f5fed JA |
54 | /* use iter_iov() to get the current vec */ |
55 | const struct iovec *__iov; | |
a280455f | 56 | const struct kvec *kvec; |
62a8067a | 57 | const struct bio_vec *bvec; |
7ff50620 | 58 | struct xarray *xarray; |
241699cd | 59 | struct pipe_inode_info *pipe; |
fcb14cb1 | 60 | void __user *ubuf; |
241699cd AV |
61 | }; |
62 | union { | |
63 | unsigned long nr_segs; | |
27c0e374 | 64 | struct { |
8cefc107 DH |
65 | unsigned int head; |
66 | unsigned int start_head; | |
27c0e374 | 67 | }; |
7ff50620 | 68 | loff_t xarray_start; |
62a8067a | 69 | }; |
92236878 KO |
70 | }; |
71 | ||
de4f5fed JA |
72 | #define iter_iov(iter) (iter)->__iov |
73 | ||
00e23707 DH |
74 | static inline enum iter_type iov_iter_type(const struct iov_iter *i) |
75 | { | |
8cd54c1c | 76 | return i->iter_type; |
00e23707 DH |
77 | } |
78 | ||
8fb0f47a JA |
79 | static inline void iov_iter_save_state(struct iov_iter *iter, |
80 | struct iov_iter_state *state) | |
81 | { | |
82 | state->iov_offset = iter->iov_offset; | |
83 | state->count = iter->count; | |
84 | state->nr_segs = iter->nr_segs; | |
85 | } | |
86 | ||
fcb14cb1 AV |
87 | static inline bool iter_is_ubuf(const struct iov_iter *i) |
88 | { | |
89 | return iov_iter_type(i) == ITER_UBUF; | |
90 | } | |
91 | ||
00e23707 DH |
92 | static inline bool iter_is_iovec(const struct iov_iter *i) |
93 | { | |
94 | return iov_iter_type(i) == ITER_IOVEC; | |
95 | } | |
96 | ||
97 | static inline bool iov_iter_is_kvec(const struct iov_iter *i) | |
98 | { | |
99 | return iov_iter_type(i) == ITER_KVEC; | |
100 | } | |
101 | ||
102 | static inline bool iov_iter_is_bvec(const struct iov_iter *i) | |
103 | { | |
104 | return iov_iter_type(i) == ITER_BVEC; | |
105 | } | |
106 | ||
107 | static inline bool iov_iter_is_pipe(const struct iov_iter *i) | |
108 | { | |
109 | return iov_iter_type(i) == ITER_PIPE; | |
110 | } | |
111 | ||
9ea9ce04 DH |
112 | static inline bool iov_iter_is_discard(const struct iov_iter *i) |
113 | { | |
114 | return iov_iter_type(i) == ITER_DISCARD; | |
115 | } | |
116 | ||
7ff50620 DH |
117 | static inline bool iov_iter_is_xarray(const struct iov_iter *i) |
118 | { | |
119 | return iov_iter_type(i) == ITER_XARRAY; | |
120 | } | |
121 | ||
00e23707 DH |
122 | static inline unsigned char iov_iter_rw(const struct iov_iter *i) |
123 | { | |
8cd54c1c | 124 | return i->data_source ? WRITE : READ; |
00e23707 DH |
125 | } |
126 | ||
fcb14cb1 AV |
127 | static inline bool user_backed_iter(const struct iov_iter *i) |
128 | { | |
129 | return i->user_backed; | |
130 | } | |
131 | ||
1da177e4 LT |
132 | /* |
133 | * Total number of bytes covered by an iovec. | |
134 | * | |
135 | * NOTE that it is not safe to use this function until all the iovec's | |
136 | * segment lengths have been validated. Because the individual lengths can | |
137 | * overflow a size_t when added together. | |
138 | */ | |
139 | static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) | |
140 | { | |
141 | unsigned long seg; | |
142 | size_t ret = 0; | |
143 | ||
144 | for (seg = 0; seg < nr_segs; seg++) | |
145 | ret += iov[seg].iov_len; | |
146 | return ret; | |
147 | } | |
148 | ||
92236878 KO |
149 | static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) |
150 | { | |
151 | return (struct iovec) { | |
de4f5fed | 152 | .iov_base = iter_iov(iter)->iov_base + iter->iov_offset, |
92236878 | 153 | .iov_len = min(iter->count, |
de4f5fed | 154 | iter_iov(iter)->iov_len - iter->iov_offset), |
92236878 KO |
155 | }; |
156 | } | |
157 | ||
f0b65f39 AV |
158 | size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, |
159 | size_t bytes, struct iov_iter *i); | |
92236878 | 160 | void iov_iter_advance(struct iov_iter *i, size_t bytes); |
27c0e374 | 161 | void iov_iter_revert(struct iov_iter *i, size_t bytes); |
a6294593 | 162 | size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t bytes); |
cdd591fc | 163 | size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t bytes); |
92236878 | 164 | size_t iov_iter_single_seg_count(const struct iov_iter *i); |
6e58e79d AV |
165 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
166 | struct iov_iter *i); | |
f0d1bec9 AV |
167 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
168 | struct iov_iter *i); | |
aa28de27 AV |
169 | |
170 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i); | |
171 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i); | |
aa28de27 | 172 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i); |
aa28de27 | 173 | |
d9c19d32 MWO |
174 | static inline size_t copy_folio_to_iter(struct folio *folio, size_t offset, |
175 | size_t bytes, struct iov_iter *i) | |
176 | { | |
177 | return copy_page_to_iter(&folio->page, offset, bytes, i); | |
178 | } | |
179 | ||
aa28de27 AV |
180 | static __always_inline __must_check |
181 | size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) | |
182 | { | |
0e3c3b90 | 183 | if (check_copy_size(addr, bytes, true)) |
aa28de27 | 184 | return _copy_to_iter(addr, bytes, i); |
0e3c3b90 | 185 | return 0; |
aa28de27 AV |
186 | } |
187 | ||
188 | static __always_inline __must_check | |
189 | size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) | |
190 | { | |
0e3c3b90 | 191 | if (check_copy_size(addr, bytes, false)) |
aa28de27 | 192 | return _copy_from_iter(addr, bytes, i); |
0e3c3b90 | 193 | return 0; |
aa28de27 AV |
194 | } |
195 | ||
196 | static __always_inline __must_check | |
197 | bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) | |
198 | { | |
4b6c132b AV |
199 | size_t copied = copy_from_iter(addr, bytes, i); |
200 | if (likely(copied == bytes)) | |
201 | return true; | |
202 | iov_iter_revert(i, copied); | |
203 | return false; | |
aa28de27 AV |
204 | } |
205 | ||
206 | static __always_inline __must_check | |
207 | size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
208 | { | |
0e3c3b90 | 209 | if (check_copy_size(addr, bytes, false)) |
aa28de27 | 210 | return _copy_from_iter_nocache(addr, bytes, i); |
0e3c3b90 | 211 | return 0; |
aa28de27 AV |
212 | } |
213 | ||
214 | static __always_inline __must_check | |
215 | bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
216 | { | |
4b6c132b AV |
217 | size_t copied = copy_from_iter_nocache(addr, bytes, i); |
218 | if (likely(copied == bytes)) | |
219 | return true; | |
220 | iov_iter_revert(i, copied); | |
221 | return false; | |
aa28de27 AV |
222 | } |
223 | ||
0aed55af DW |
224 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
225 | /* | |
226 | * Note, users like pmem that depend on the stricter semantics of | |
e17f7a0b | 227 | * _copy_from_iter_flushcache() than _copy_from_iter_nocache() must check for |
0aed55af DW |
228 | * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the |
229 | * destination is flushed from the cache on return. | |
230 | */ | |
6a37e940 | 231 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i); |
0aed55af | 232 | #else |
6a37e940 LT |
233 | #define _copy_from_iter_flushcache _copy_from_iter_nocache |
234 | #endif | |
235 | ||
ec6347bb DW |
236 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
237 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i); | |
8780356e | 238 | #else |
ec6347bb | 239 | #define _copy_mc_to_iter _copy_to_iter |
8780356e DW |
240 | #endif |
241 | ||
c35e0248 | 242 | size_t iov_iter_zero(size_t bytes, struct iov_iter *); |
cfa320f7 KB |
243 | bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, |
244 | unsigned len_mask); | |
886a3911 | 245 | unsigned long iov_iter_alignment(const struct iov_iter *i); |
357f435d | 246 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i); |
aa563d7b | 247 | void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov, |
71d8e532 | 248 | unsigned long nr_segs, size_t count); |
aa563d7b | 249 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec, |
05afcb77 | 250 | unsigned long nr_segs, size_t count); |
aa563d7b | 251 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec, |
abb78f87 | 252 | unsigned long nr_segs, size_t count); |
aa563d7b | 253 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe, |
241699cd | 254 | size_t count); |
9ea9ce04 | 255 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count); |
7ff50620 DH |
256 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray, |
257 | loff_t start, size_t count); | |
d8207640 LG |
258 | ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, |
259 | size_t maxsize, unsigned maxpages, size_t *start, | |
f62e52d1 | 260 | iov_iter_extraction_t extraction_flags); |
eba2d3d7 | 261 | ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages, |
2c80929c | 262 | size_t maxsize, unsigned maxpages, size_t *start); |
d8207640 LG |
263 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
264 | struct page ***pages, size_t maxsize, size_t *start, | |
f62e52d1 | 265 | iov_iter_extraction_t extraction_flags); |
eba2d3d7 | 266 | ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages, |
91f79c43 | 267 | size_t maxsize, size_t *start); |
f67da30c | 268 | int iov_iter_npages(const struct iov_iter *i, int maxpages); |
8fb0f47a | 269 | void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state); |
92236878 | 270 | |
4b8164b9 AV |
271 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags); |
272 | ||
b57332b4 | 273 | static inline size_t iov_iter_count(const struct iov_iter *i) |
92236878 KO |
274 | { |
275 | return i->count; | |
276 | } | |
277 | ||
0b86dbf6 AV |
278 | /* |
279 | * Cap the iov_iter by given limit; note that the second argument is | |
280 | * *not* the new size - it's upper limit for such. Passing it a value | |
281 | * greater than the amount of data in iov_iter is fine - it'll just do | |
282 | * nothing in that case. | |
283 | */ | |
284 | static inline void iov_iter_truncate(struct iov_iter *i, u64 count) | |
0c949334 | 285 | { |
0b86dbf6 AV |
286 | /* |
287 | * count doesn't have to fit in size_t - comparison extends both | |
288 | * operands to u64 here and any value that would be truncated by | |
289 | * conversion in assignement is by definition greater than all | |
290 | * values of size_t, including old i->count. | |
291 | */ | |
7dedd3e1 | 292 | if (i->count > count) |
0c949334 AV |
293 | i->count = count; |
294 | } | |
295 | ||
b42b15fd AV |
296 | /* |
297 | * reexpand a previously truncated iterator; count must be no more than how much | |
298 | * we had shrunk it. | |
299 | */ | |
300 | static inline void iov_iter_reexpand(struct iov_iter *i, size_t count) | |
301 | { | |
302 | i->count = count; | |
303 | } | |
52cbd23a | 304 | |
b93235e6 JK |
305 | static inline int |
306 | iov_iter_npages_cap(struct iov_iter *i, int maxpages, size_t max_bytes) | |
307 | { | |
308 | size_t shorted = 0; | |
309 | int npages; | |
310 | ||
311 | if (iov_iter_count(i) > max_bytes) { | |
312 | shorted = iov_iter_count(i) - max_bytes; | |
313 | iov_iter_truncate(i, max_bytes); | |
314 | } | |
7187440d | 315 | npages = iov_iter_npages(i, maxpages); |
b93235e6 JK |
316 | if (shorted) |
317 | iov_iter_reexpand(i, iov_iter_count(i) + shorted); | |
318 | ||
319 | return npages; | |
320 | } | |
321 | ||
52cbd23a WB |
322 | struct csum_state { |
323 | __wsum csum; | |
324 | size_t off; | |
325 | }; | |
326 | ||
327 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i); | |
a604ec7e | 328 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i); |
4b6c132b AV |
329 | |
330 | static __always_inline __must_check | |
331 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, | |
332 | __wsum *csum, struct iov_iter *i) | |
333 | { | |
334 | size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i); | |
335 | if (likely(copied == bytes)) | |
336 | return true; | |
337 | iov_iter_revert(i, copied); | |
338 | return false; | |
339 | } | |
d05f4435 SG |
340 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
341 | struct iov_iter *i); | |
b42b15fd | 342 | |
bfdc5970 CH |
343 | struct iovec *iovec_from_user(const struct iovec __user *uvector, |
344 | unsigned long nr_segs, unsigned long fast_segs, | |
345 | struct iovec *fast_iov, bool compat); | |
346 | ssize_t import_iovec(int type, const struct iovec __user *uvec, | |
347 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
348 | struct iov_iter *i); | |
349 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
350 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
351 | struct iov_iter *i, bool compat); | |
bc917be8 AV |
352 | int import_single_range(int type, void __user *buf, size_t len, |
353 | struct iovec *iov, struct iov_iter *i); | |
2ad9bd83 | 354 | int import_ubuf(int type, void __user *buf, size_t len, struct iov_iter *i); |
bc917be8 | 355 | |
fcb14cb1 AV |
356 | static inline void iov_iter_ubuf(struct iov_iter *i, unsigned int direction, |
357 | void __user *buf, size_t count) | |
358 | { | |
359 | WARN_ON(direction & ~(READ | WRITE)); | |
360 | *i = (struct iov_iter) { | |
361 | .iter_type = ITER_UBUF, | |
362 | .user_backed = true, | |
363 | .data_source = direction, | |
364 | .ubuf = buf, | |
365 | .count = count | |
366 | }; | |
367 | } | |
f62e52d1 DH |
368 | /* Flags for iov_iter_get/extract_pages*() */ |
369 | /* Allow P2PDMA on the extracted pages */ | |
370 | #define ITER_ALLOW_P2PDMA ((__force iov_iter_extraction_t)0x01) | |
371 | ||
7d58fe73 DH |
372 | ssize_t iov_iter_extract_pages(struct iov_iter *i, struct page ***pages, |
373 | size_t maxsize, unsigned int maxpages, | |
374 | iov_iter_extraction_t extraction_flags, | |
375 | size_t *offset0); | |
376 | ||
377 | /** | |
378 | * iov_iter_extract_will_pin - Indicate how pages from the iterator will be retained | |
379 | * @iter: The iterator | |
380 | * | |
381 | * Examine the iterator and indicate by returning true or false as to how, if | |
382 | * at all, pages extracted from the iterator will be retained by the extraction | |
383 | * function. | |
384 | * | |
385 | * %true indicates that the pages will have a pin placed in them that the | |
386 | * caller must unpin. This is must be done for DMA/async DIO to force fork() | |
387 | * to forcibly copy a page for the child (the parent must retain the original | |
388 | * page). | |
389 | * | |
390 | * %false indicates that no measures are taken and that it's up to the caller | |
391 | * to retain the pages. | |
392 | */ | |
393 | static inline bool iov_iter_extract_will_pin(const struct iov_iter *iter) | |
394 | { | |
395 | return user_backed_iter(iter); | |
396 | } | |
fcb14cb1 | 397 | |
812ed032 | 398 | #endif |