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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> |
607ca46e | 10 | #include <uapi/linux/uio.h> |
1da177e4 | 11 | |
92236878 | 12 | struct page; |
241699cd | 13 | struct pipe_inode_info; |
812ed032 JS |
14 | |
15 | struct kvec { | |
16 | void *iov_base; /* and that should *never* hold a userland pointer */ | |
17 | size_t iov_len; | |
18 | }; | |
19 | ||
00e23707 | 20 | enum iter_type { |
875f1d07 JA |
21 | /* iter types */ |
22 | ITER_IOVEC = 4, | |
23 | ITER_KVEC = 8, | |
24 | ITER_BVEC = 16, | |
25 | ITER_PIPE = 32, | |
26 | ITER_DISCARD = 64, | |
7ff50620 | 27 | ITER_XARRAY = 128, |
62a8067a AV |
28 | }; |
29 | ||
92236878 | 30 | struct iov_iter { |
875f1d07 JA |
31 | /* |
32 | * Bit 0 is the read/write bit, set if we're writing. | |
33 | * Bit 1 is the BVEC_FLAG_NO_REF bit, set if type is a bvec and | |
34 | * the caller isn't expecting to drop a page reference when done. | |
35 | */ | |
aa563d7b | 36 | unsigned int type; |
92236878 KO |
37 | size_t iov_offset; |
38 | size_t count; | |
62a8067a AV |
39 | union { |
40 | const struct iovec *iov; | |
a280455f | 41 | const struct kvec *kvec; |
62a8067a | 42 | const struct bio_vec *bvec; |
7ff50620 | 43 | struct xarray *xarray; |
241699cd AV |
44 | struct pipe_inode_info *pipe; |
45 | }; | |
46 | union { | |
47 | unsigned long nr_segs; | |
27c0e374 | 48 | struct { |
8cefc107 DH |
49 | unsigned int head; |
50 | unsigned int start_head; | |
27c0e374 | 51 | }; |
7ff50620 | 52 | loff_t xarray_start; |
62a8067a | 53 | }; |
92236878 KO |
54 | }; |
55 | ||
00e23707 DH |
56 | static inline enum iter_type iov_iter_type(const struct iov_iter *i) |
57 | { | |
b6207430 | 58 | return i->type & ~(READ | WRITE); |
00e23707 DH |
59 | } |
60 | ||
61 | static inline bool iter_is_iovec(const struct iov_iter *i) | |
62 | { | |
63 | return iov_iter_type(i) == ITER_IOVEC; | |
64 | } | |
65 | ||
66 | static inline bool iov_iter_is_kvec(const struct iov_iter *i) | |
67 | { | |
68 | return iov_iter_type(i) == ITER_KVEC; | |
69 | } | |
70 | ||
71 | static inline bool iov_iter_is_bvec(const struct iov_iter *i) | |
72 | { | |
73 | return iov_iter_type(i) == ITER_BVEC; | |
74 | } | |
75 | ||
76 | static inline bool iov_iter_is_pipe(const struct iov_iter *i) | |
77 | { | |
78 | return iov_iter_type(i) == ITER_PIPE; | |
79 | } | |
80 | ||
9ea9ce04 DH |
81 | static inline bool iov_iter_is_discard(const struct iov_iter *i) |
82 | { | |
83 | return iov_iter_type(i) == ITER_DISCARD; | |
84 | } | |
85 | ||
7ff50620 DH |
86 | static inline bool iov_iter_is_xarray(const struct iov_iter *i) |
87 | { | |
88 | return iov_iter_type(i) == ITER_XARRAY; | |
89 | } | |
90 | ||
00e23707 DH |
91 | static inline unsigned char iov_iter_rw(const struct iov_iter *i) |
92 | { | |
93 | return i->type & (READ | WRITE); | |
94 | } | |
95 | ||
1da177e4 LT |
96 | /* |
97 | * Total number of bytes covered by an iovec. | |
98 | * | |
99 | * NOTE that it is not safe to use this function until all the iovec's | |
100 | * segment lengths have been validated. Because the individual lengths can | |
101 | * overflow a size_t when added together. | |
102 | */ | |
103 | static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) | |
104 | { | |
105 | unsigned long seg; | |
106 | size_t ret = 0; | |
107 | ||
108 | for (seg = 0; seg < nr_segs; seg++) | |
109 | ret += iov[seg].iov_len; | |
110 | return ret; | |
111 | } | |
112 | ||
92236878 KO |
113 | static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) |
114 | { | |
115 | return (struct iovec) { | |
116 | .iov_base = iter->iov->iov_base + iter->iov_offset, | |
117 | .iov_len = min(iter->count, | |
118 | iter->iov->iov_len - iter->iov_offset), | |
119 | }; | |
120 | } | |
121 | ||
92236878 KO |
122 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
123 | struct iov_iter *i, unsigned long offset, size_t bytes); | |
92236878 | 124 | void iov_iter_advance(struct iov_iter *i, size_t bytes); |
27c0e374 | 125 | void iov_iter_revert(struct iov_iter *i, size_t bytes); |
92236878 KO |
126 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes); |
127 | size_t iov_iter_single_seg_count(const struct iov_iter *i); | |
6e58e79d AV |
128 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
129 | struct iov_iter *i); | |
f0d1bec9 AV |
130 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
131 | struct iov_iter *i); | |
aa28de27 AV |
132 | |
133 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i); | |
134 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i); | |
135 | bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i); | |
136 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i); | |
137 | bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i); | |
138 | ||
139 | static __always_inline __must_check | |
140 | size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) | |
141 | { | |
142 | if (unlikely(!check_copy_size(addr, bytes, true))) | |
c43aeb19 | 143 | return 0; |
aa28de27 AV |
144 | else |
145 | return _copy_to_iter(addr, bytes, i); | |
146 | } | |
147 | ||
148 | static __always_inline __must_check | |
149 | size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) | |
150 | { | |
151 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
c43aeb19 | 152 | return 0; |
aa28de27 AV |
153 | else |
154 | return _copy_from_iter(addr, bytes, i); | |
155 | } | |
156 | ||
157 | static __always_inline __must_check | |
158 | bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) | |
159 | { | |
160 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
161 | return false; | |
162 | else | |
163 | return _copy_from_iter_full(addr, bytes, i); | |
164 | } | |
165 | ||
166 | static __always_inline __must_check | |
167 | size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
168 | { | |
169 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
c43aeb19 | 170 | return 0; |
aa28de27 AV |
171 | else |
172 | return _copy_from_iter_nocache(addr, bytes, i); | |
173 | } | |
174 | ||
175 | static __always_inline __must_check | |
176 | bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
177 | { | |
178 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
179 | return false; | |
180 | else | |
181 | return _copy_from_iter_full_nocache(addr, bytes, i); | |
182 | } | |
183 | ||
0aed55af DW |
184 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
185 | /* | |
186 | * Note, users like pmem that depend on the stricter semantics of | |
187 | * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for | |
188 | * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the | |
189 | * destination is flushed from the cache on return. | |
190 | */ | |
6a37e940 | 191 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i); |
0aed55af | 192 | #else |
6a37e940 LT |
193 | #define _copy_from_iter_flushcache _copy_from_iter_nocache |
194 | #endif | |
195 | ||
ec6347bb DW |
196 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
197 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i); | |
8780356e | 198 | #else |
ec6347bb | 199 | #define _copy_mc_to_iter _copy_to_iter |
8780356e DW |
200 | #endif |
201 | ||
6a37e940 LT |
202 | static __always_inline __must_check |
203 | size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) | |
0aed55af | 204 | { |
6a37e940 | 205 | if (unlikely(!check_copy_size(addr, bytes, false))) |
c43aeb19 | 206 | return 0; |
6a37e940 LT |
207 | else |
208 | return _copy_from_iter_flushcache(addr, bytes, i); | |
0aed55af | 209 | } |
6a37e940 | 210 | |
8780356e | 211 | static __always_inline __must_check |
ec6347bb | 212 | size_t copy_mc_to_iter(void *addr, size_t bytes, struct iov_iter *i) |
8780356e | 213 | { |
dfb06cba | 214 | if (unlikely(!check_copy_size(addr, bytes, true))) |
8780356e DW |
215 | return 0; |
216 | else | |
ec6347bb | 217 | return _copy_mc_to_iter(addr, bytes, i); |
8780356e DW |
218 | } |
219 | ||
c35e0248 | 220 | size_t iov_iter_zero(size_t bytes, struct iov_iter *); |
886a3911 | 221 | unsigned long iov_iter_alignment(const struct iov_iter *i); |
357f435d | 222 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i); |
aa563d7b | 223 | void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov, |
71d8e532 | 224 | unsigned long nr_segs, size_t count); |
aa563d7b | 225 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec, |
05afcb77 | 226 | unsigned long nr_segs, size_t count); |
aa563d7b | 227 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec, |
abb78f87 | 228 | unsigned long nr_segs, size_t count); |
aa563d7b | 229 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe, |
241699cd | 230 | size_t count); |
9ea9ce04 | 231 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count); |
7ff50620 DH |
232 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray, |
233 | loff_t start, size_t count); | |
7b2c99d1 | 234 | ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, |
2c80929c | 235 | size_t maxsize, unsigned maxpages, size_t *start); |
91f79c43 AV |
236 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, |
237 | size_t maxsize, size_t *start); | |
f67da30c | 238 | int iov_iter_npages(const struct iov_iter *i, int maxpages); |
92236878 | 239 | |
4b8164b9 AV |
240 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags); |
241 | ||
b57332b4 | 242 | static inline size_t iov_iter_count(const struct iov_iter *i) |
92236878 KO |
243 | { |
244 | return i->count; | |
245 | } | |
246 | ||
0b86dbf6 AV |
247 | /* |
248 | * Cap the iov_iter by given limit; note that the second argument is | |
249 | * *not* the new size - it's upper limit for such. Passing it a value | |
250 | * greater than the amount of data in iov_iter is fine - it'll just do | |
251 | * nothing in that case. | |
252 | */ | |
253 | static inline void iov_iter_truncate(struct iov_iter *i, u64 count) | |
0c949334 | 254 | { |
0b86dbf6 AV |
255 | /* |
256 | * count doesn't have to fit in size_t - comparison extends both | |
257 | * operands to u64 here and any value that would be truncated by | |
258 | * conversion in assignement is by definition greater than all | |
259 | * values of size_t, including old i->count. | |
260 | */ | |
0c949334 AV |
261 | if (i->count > count) |
262 | i->count = count; | |
263 | } | |
264 | ||
b42b15fd AV |
265 | /* |
266 | * reexpand a previously truncated iterator; count must be no more than how much | |
267 | * we had shrunk it. | |
268 | */ | |
269 | static inline void iov_iter_reexpand(struct iov_iter *i, size_t count) | |
270 | { | |
271 | i->count = count; | |
272 | } | |
52cbd23a WB |
273 | |
274 | struct csum_state { | |
275 | __wsum csum; | |
276 | size_t off; | |
277 | }; | |
278 | ||
279 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i); | |
a604ec7e | 280 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i); |
cbbd26b8 | 281 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i); |
d05f4435 SG |
282 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
283 | struct iov_iter *i); | |
b42b15fd | 284 | |
bfdc5970 CH |
285 | struct iovec *iovec_from_user(const struct iovec __user *uvector, |
286 | unsigned long nr_segs, unsigned long fast_segs, | |
287 | struct iovec *fast_iov, bool compat); | |
288 | ssize_t import_iovec(int type, const struct iovec __user *uvec, | |
289 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
290 | struct iov_iter *i); | |
291 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
292 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
293 | struct iov_iter *i, bool compat); | |
bc917be8 AV |
294 | int import_single_range(int type, void __user *buf, size_t len, |
295 | struct iovec *iov, struct iov_iter *i); | |
296 | ||
09cf698a AV |
297 | int iov_iter_for_each_range(struct iov_iter *i, size_t bytes, |
298 | int (*f)(struct kvec *vec, void *context), | |
299 | void *context); | |
300 | ||
812ed032 | 301 | #endif |