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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Berkeley style UIO structures - Alan Cox 1994. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | */ | |
607ca46e DH |
9 | #ifndef __LINUX_UIO_H |
10 | #define __LINUX_UIO_H | |
1da177e4 | 11 | |
92236878 | 12 | #include <linux/kernel.h> |
aa28de27 | 13 | #include <linux/thread_info.h> |
607ca46e | 14 | #include <uapi/linux/uio.h> |
1da177e4 | 15 | |
92236878 | 16 | struct page; |
241699cd | 17 | struct pipe_inode_info; |
812ed032 JS |
18 | |
19 | struct kvec { | |
20 | void *iov_base; /* and that should *never* hold a userland pointer */ | |
21 | size_t iov_len; | |
22 | }; | |
23 | ||
62a8067a AV |
24 | enum { |
25 | ITER_IOVEC = 0, | |
26 | ITER_KVEC = 2, | |
27 | ITER_BVEC = 4, | |
241699cd | 28 | ITER_PIPE = 8, |
62a8067a AV |
29 | }; |
30 | ||
92236878 | 31 | struct iov_iter { |
71d8e532 | 32 | int type; |
92236878 KO |
33 | size_t iov_offset; |
34 | size_t count; | |
62a8067a AV |
35 | union { |
36 | const struct iovec *iov; | |
a280455f | 37 | const struct kvec *kvec; |
62a8067a | 38 | const struct bio_vec *bvec; |
241699cd AV |
39 | struct pipe_inode_info *pipe; |
40 | }; | |
41 | union { | |
42 | unsigned long nr_segs; | |
27c0e374 AV |
43 | struct { |
44 | int idx; | |
45 | int start_idx; | |
46 | }; | |
62a8067a | 47 | }; |
92236878 KO |
48 | }; |
49 | ||
1da177e4 LT |
50 | /* |
51 | * Total number of bytes covered by an iovec. | |
52 | * | |
53 | * NOTE that it is not safe to use this function until all the iovec's | |
54 | * segment lengths have been validated. Because the individual lengths can | |
55 | * overflow a size_t when added together. | |
56 | */ | |
57 | static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) | |
58 | { | |
59 | unsigned long seg; | |
60 | size_t ret = 0; | |
61 | ||
62 | for (seg = 0; seg < nr_segs; seg++) | |
63 | ret += iov[seg].iov_len; | |
64 | return ret; | |
65 | } | |
66 | ||
92236878 KO |
67 | static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) |
68 | { | |
69 | return (struct iovec) { | |
70 | .iov_base = iter->iov->iov_base + iter->iov_offset, | |
71 | .iov_len = min(iter->count, | |
72 | iter->iov->iov_len - iter->iov_offset), | |
73 | }; | |
74 | } | |
75 | ||
76 | #define iov_for_each(iov, iter, start) \ | |
241699cd | 77 | if (!((start).type & (ITER_BVEC | ITER_PIPE))) \ |
92236878 KO |
78 | for (iter = (start); \ |
79 | (iter).count && \ | |
80 | ((iov = iov_iter_iovec(&(iter))), 1); \ | |
81 | iov_iter_advance(&(iter), (iov).iov_len)) | |
82 | ||
92236878 KO |
83 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
84 | struct iov_iter *i, unsigned long offset, size_t bytes); | |
92236878 | 85 | void iov_iter_advance(struct iov_iter *i, size_t bytes); |
27c0e374 | 86 | void iov_iter_revert(struct iov_iter *i, size_t bytes); |
92236878 KO |
87 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes); |
88 | size_t iov_iter_single_seg_count(const struct iov_iter *i); | |
6e58e79d AV |
89 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
90 | struct iov_iter *i); | |
f0d1bec9 AV |
91 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
92 | struct iov_iter *i); | |
aa28de27 AV |
93 | |
94 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i); | |
95 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i); | |
96 | bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i); | |
97 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i); | |
98 | bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i); | |
99 | ||
100 | static __always_inline __must_check | |
101 | size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) | |
102 | { | |
103 | if (unlikely(!check_copy_size(addr, bytes, true))) | |
c43aeb19 | 104 | return 0; |
aa28de27 AV |
105 | else |
106 | return _copy_to_iter(addr, bytes, i); | |
107 | } | |
108 | ||
109 | static __always_inline __must_check | |
110 | size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) | |
111 | { | |
112 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
c43aeb19 | 113 | return 0; |
aa28de27 AV |
114 | else |
115 | return _copy_from_iter(addr, bytes, i); | |
116 | } | |
117 | ||
118 | static __always_inline __must_check | |
119 | bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) | |
120 | { | |
121 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
122 | return false; | |
123 | else | |
124 | return _copy_from_iter_full(addr, bytes, i); | |
125 | } | |
126 | ||
127 | static __always_inline __must_check | |
128 | size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
129 | { | |
130 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
c43aeb19 | 131 | return 0; |
aa28de27 AV |
132 | else |
133 | return _copy_from_iter_nocache(addr, bytes, i); | |
134 | } | |
135 | ||
136 | static __always_inline __must_check | |
137 | bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) | |
138 | { | |
139 | if (unlikely(!check_copy_size(addr, bytes, false))) | |
140 | return false; | |
141 | else | |
142 | return _copy_from_iter_full_nocache(addr, bytes, i); | |
143 | } | |
144 | ||
0aed55af DW |
145 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
146 | /* | |
147 | * Note, users like pmem that depend on the stricter semantics of | |
148 | * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for | |
149 | * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the | |
150 | * destination is flushed from the cache on return. | |
151 | */ | |
6a37e940 | 152 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i); |
0aed55af | 153 | #else |
6a37e940 LT |
154 | #define _copy_from_iter_flushcache _copy_from_iter_nocache |
155 | #endif | |
156 | ||
157 | static __always_inline __must_check | |
158 | size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) | |
0aed55af | 159 | { |
6a37e940 | 160 | if (unlikely(!check_copy_size(addr, bytes, false))) |
c43aeb19 | 161 | return 0; |
6a37e940 LT |
162 | else |
163 | return _copy_from_iter_flushcache(addr, bytes, i); | |
0aed55af | 164 | } |
6a37e940 | 165 | |
c35e0248 | 166 | size_t iov_iter_zero(size_t bytes, struct iov_iter *); |
886a3911 | 167 | unsigned long iov_iter_alignment(const struct iov_iter *i); |
357f435d | 168 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i); |
71d8e532 AV |
169 | void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov, |
170 | unsigned long nr_segs, size_t count); | |
05afcb77 AV |
171 | void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec, |
172 | unsigned long nr_segs, size_t count); | |
173 | void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec, | |
abb78f87 | 174 | unsigned long nr_segs, size_t count); |
241699cd AV |
175 | void iov_iter_pipe(struct iov_iter *i, int direction, struct pipe_inode_info *pipe, |
176 | size_t count); | |
7b2c99d1 | 177 | ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, |
2c80929c | 178 | size_t maxsize, unsigned maxpages, size_t *start); |
91f79c43 AV |
179 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, |
180 | size_t maxsize, size_t *start); | |
f67da30c | 181 | int iov_iter_npages(const struct iov_iter *i, int maxpages); |
92236878 | 182 | |
4b8164b9 AV |
183 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags); |
184 | ||
b57332b4 | 185 | static inline size_t iov_iter_count(const struct iov_iter *i) |
92236878 KO |
186 | { |
187 | return i->count; | |
188 | } | |
189 | ||
b57332b4 | 190 | static inline bool iter_is_iovec(const struct iov_iter *i) |
777eda2c | 191 | { |
241699cd | 192 | return !(i->type & (ITER_BVEC | ITER_KVEC | ITER_PIPE)); |
777eda2c AV |
193 | } |
194 | ||
bd8e0ff9 OS |
195 | /* |
196 | * Get one of READ or WRITE out of iter->type without any other flags OR'd in | |
197 | * with it. | |
198 | * | |
199 | * The ?: is just for type safety. | |
200 | */ | |
d3849953 | 201 | #define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & (READ | WRITE)) |
bd8e0ff9 | 202 | |
0b86dbf6 AV |
203 | /* |
204 | * Cap the iov_iter by given limit; note that the second argument is | |
205 | * *not* the new size - it's upper limit for such. Passing it a value | |
206 | * greater than the amount of data in iov_iter is fine - it'll just do | |
207 | * nothing in that case. | |
208 | */ | |
209 | static inline void iov_iter_truncate(struct iov_iter *i, u64 count) | |
0c949334 | 210 | { |
0b86dbf6 AV |
211 | /* |
212 | * count doesn't have to fit in size_t - comparison extends both | |
213 | * operands to u64 here and any value that would be truncated by | |
214 | * conversion in assignement is by definition greater than all | |
215 | * values of size_t, including old i->count. | |
216 | */ | |
0c949334 AV |
217 | if (i->count > count) |
218 | i->count = count; | |
219 | } | |
220 | ||
b42b15fd AV |
221 | /* |
222 | * reexpand a previously truncated iterator; count must be no more than how much | |
223 | * we had shrunk it. | |
224 | */ | |
225 | static inline void iov_iter_reexpand(struct iov_iter *i, size_t count) | |
226 | { | |
227 | i->count = count; | |
228 | } | |
36f7a8a4 | 229 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, struct iov_iter *i); |
a604ec7e | 230 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i); |
cbbd26b8 | 231 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i); |
b42b15fd | 232 | |
bc917be8 AV |
233 | int import_iovec(int type, const struct iovec __user * uvector, |
234 | unsigned nr_segs, unsigned fast_segs, | |
235 | struct iovec **iov, struct iov_iter *i); | |
236 | ||
237 | #ifdef CONFIG_COMPAT | |
238 | struct compat_iovec; | |
239 | int compat_import_iovec(int type, const struct compat_iovec __user * uvector, | |
240 | unsigned nr_segs, unsigned fast_segs, | |
241 | struct iovec **iov, struct iov_iter *i); | |
242 | #endif | |
243 | ||
244 | int import_single_range(int type, void __user *buf, size_t len, | |
245 | struct iovec *iov, struct iov_iter *i); | |
246 | ||
09cf698a AV |
247 | int iov_iter_for_each_range(struct iov_iter *i, size_t bytes, |
248 | int (*f)(struct kvec *vec, void *context), | |
249 | void *context); | |
250 | ||
812ed032 | 251 | #endif |