2 * Berkeley style UIO structures - Alan Cox 1994.
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.
12 #include <linux/kernel.h>
13 #include <linux/thread_info.h>
14 #include <crypto/hash.h>
15 #include <uapi/linux/uio.h>
18 struct pipe_inode_info
;
21 void *iov_base
; /* and that should *never* hold a userland pointer */
26 /* set if ITER_BVEC doesn't hold a bv_page ref */
27 ITER_BVEC_FLAG_NO_REF
= 2,
39 * Bit 0 is the read/write bit, set if we're writing.
40 * Bit 1 is the BVEC_FLAG_NO_REF bit, set if type is a bvec and
41 * the caller isn't expecting to drop a page reference when done.
47 const struct iovec
*iov
;
48 const struct kvec
*kvec
;
49 const struct bio_vec
*bvec
;
50 struct pipe_inode_info
*pipe
;
53 unsigned long nr_segs
;
61 static inline enum iter_type
iov_iter_type(const struct iov_iter
*i
)
63 return i
->type
& ~(READ
| WRITE
);
66 static inline bool iter_is_iovec(const struct iov_iter
*i
)
68 return iov_iter_type(i
) == ITER_IOVEC
;
71 static inline bool iov_iter_is_kvec(const struct iov_iter
*i
)
73 return iov_iter_type(i
) == ITER_KVEC
;
76 static inline bool iov_iter_is_bvec(const struct iov_iter
*i
)
78 return iov_iter_type(i
) == ITER_BVEC
;
81 static inline bool iov_iter_is_pipe(const struct iov_iter
*i
)
83 return iov_iter_type(i
) == ITER_PIPE
;
86 static inline bool iov_iter_is_discard(const struct iov_iter
*i
)
88 return iov_iter_type(i
) == ITER_DISCARD
;
91 static inline unsigned char iov_iter_rw(const struct iov_iter
*i
)
93 return i
->type
& (READ
| WRITE
);
96 static inline bool iov_iter_bvec_no_ref(const struct iov_iter
*i
)
98 return (i
->type
& ITER_BVEC_FLAG_NO_REF
) != 0;
102 * Total number of bytes covered by an iovec.
104 * NOTE that it is not safe to use this function until all the iovec's
105 * segment lengths have been validated. Because the individual lengths can
106 * overflow a size_t when added together.
108 static inline size_t iov_length(const struct iovec
*iov
, unsigned long nr_segs
)
113 for (seg
= 0; seg
< nr_segs
; seg
++)
114 ret
+= iov
[seg
].iov_len
;
118 static inline struct iovec
iov_iter_iovec(const struct iov_iter
*iter
)
120 return (struct iovec
) {
121 .iov_base
= iter
->iov
->iov_base
+ iter
->iov_offset
,
122 .iov_len
= min(iter
->count
,
123 iter
->iov
->iov_len
- iter
->iov_offset
),
127 size_t iov_iter_copy_from_user_atomic(struct page
*page
,
128 struct iov_iter
*i
, unsigned long offset
, size_t bytes
);
129 void iov_iter_advance(struct iov_iter
*i
, size_t bytes
);
130 void iov_iter_revert(struct iov_iter
*i
, size_t bytes
);
131 int iov_iter_fault_in_readable(struct iov_iter
*i
, size_t bytes
);
132 size_t iov_iter_single_seg_count(const struct iov_iter
*i
);
133 size_t copy_page_to_iter(struct page
*page
, size_t offset
, size_t bytes
,
135 size_t copy_page_from_iter(struct page
*page
, size_t offset
, size_t bytes
,
138 size_t _copy_to_iter(const void *addr
, size_t bytes
, struct iov_iter
*i
);
139 size_t _copy_from_iter(void *addr
, size_t bytes
, struct iov_iter
*i
);
140 bool _copy_from_iter_full(void *addr
, size_t bytes
, struct iov_iter
*i
);
141 size_t _copy_from_iter_nocache(void *addr
, size_t bytes
, struct iov_iter
*i
);
142 bool _copy_from_iter_full_nocache(void *addr
, size_t bytes
, struct iov_iter
*i
);
144 static __always_inline __must_check
145 size_t copy_to_iter(const void *addr
, size_t bytes
, struct iov_iter
*i
)
147 if (unlikely(!check_copy_size(addr
, bytes
, true)))
150 return _copy_to_iter(addr
, bytes
, i
);
153 static __always_inline __must_check
154 size_t copy_from_iter(void *addr
, size_t bytes
, struct iov_iter
*i
)
156 if (unlikely(!check_copy_size(addr
, bytes
, false)))
159 return _copy_from_iter(addr
, bytes
, i
);
162 static __always_inline __must_check
163 bool copy_from_iter_full(void *addr
, size_t bytes
, struct iov_iter
*i
)
165 if (unlikely(!check_copy_size(addr
, bytes
, false)))
168 return _copy_from_iter_full(addr
, bytes
, i
);
171 static __always_inline __must_check
172 size_t copy_from_iter_nocache(void *addr
, size_t bytes
, struct iov_iter
*i
)
174 if (unlikely(!check_copy_size(addr
, bytes
, false)))
177 return _copy_from_iter_nocache(addr
, bytes
, i
);
180 static __always_inline __must_check
181 bool copy_from_iter_full_nocache(void *addr
, size_t bytes
, struct iov_iter
*i
)
183 if (unlikely(!check_copy_size(addr
, bytes
, false)))
186 return _copy_from_iter_full_nocache(addr
, bytes
, i
);
189 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
191 * Note, users like pmem that depend on the stricter semantics of
192 * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
193 * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
194 * destination is flushed from the cache on return.
196 size_t _copy_from_iter_flushcache(void *addr
, size_t bytes
, struct iov_iter
*i
);
198 #define _copy_from_iter_flushcache _copy_from_iter_nocache
201 #ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
202 size_t _copy_to_iter_mcsafe(const void *addr
, size_t bytes
, struct iov_iter
*i
);
204 #define _copy_to_iter_mcsafe _copy_to_iter
207 static __always_inline __must_check
208 size_t copy_from_iter_flushcache(void *addr
, size_t bytes
, struct iov_iter
*i
)
210 if (unlikely(!check_copy_size(addr
, bytes
, false)))
213 return _copy_from_iter_flushcache(addr
, bytes
, i
);
216 static __always_inline __must_check
217 size_t copy_to_iter_mcsafe(void *addr
, size_t bytes
, struct iov_iter
*i
)
219 if (unlikely(!check_copy_size(addr
, bytes
, true)))
222 return _copy_to_iter_mcsafe(addr
, bytes
, i
);
225 size_t iov_iter_zero(size_t bytes
, struct iov_iter
*);
226 unsigned long iov_iter_alignment(const struct iov_iter
*i
);
227 unsigned long iov_iter_gap_alignment(const struct iov_iter
*i
);
228 void iov_iter_init(struct iov_iter
*i
, unsigned int direction
, const struct iovec
*iov
,
229 unsigned long nr_segs
, size_t count
);
230 void iov_iter_kvec(struct iov_iter
*i
, unsigned int direction
, const struct kvec
*kvec
,
231 unsigned long nr_segs
, size_t count
);
232 void iov_iter_bvec(struct iov_iter
*i
, unsigned int direction
, const struct bio_vec
*bvec
,
233 unsigned long nr_segs
, size_t count
);
234 void iov_iter_pipe(struct iov_iter
*i
, unsigned int direction
, struct pipe_inode_info
*pipe
,
236 void iov_iter_discard(struct iov_iter
*i
, unsigned int direction
, size_t count
);
237 ssize_t
iov_iter_get_pages(struct iov_iter
*i
, struct page
**pages
,
238 size_t maxsize
, unsigned maxpages
, size_t *start
);
239 ssize_t
iov_iter_get_pages_alloc(struct iov_iter
*i
, struct page
***pages
,
240 size_t maxsize
, size_t *start
);
241 int iov_iter_npages(const struct iov_iter
*i
, int maxpages
);
243 const void *dup_iter(struct iov_iter
*new, struct iov_iter
*old
, gfp_t flags
);
245 static inline size_t iov_iter_count(const struct iov_iter
*i
)
251 * Cap the iov_iter by given limit; note that the second argument is
252 * *not* the new size - it's upper limit for such. Passing it a value
253 * greater than the amount of data in iov_iter is fine - it'll just do
254 * nothing in that case.
256 static inline void iov_iter_truncate(struct iov_iter
*i
, u64 count
)
259 * count doesn't have to fit in size_t - comparison extends both
260 * operands to u64 here and any value that would be truncated by
261 * conversion in assignement is by definition greater than all
262 * values of size_t, including old i->count.
264 if (i
->count
> count
)
269 * reexpand a previously truncated iterator; count must be no more than how much
272 static inline void iov_iter_reexpand(struct iov_iter
*i
, size_t count
)
276 size_t csum_and_copy_to_iter(const void *addr
, size_t bytes
, void *csump
, struct iov_iter
*i
);
277 size_t csum_and_copy_from_iter(void *addr
, size_t bytes
, __wsum
*csum
, struct iov_iter
*i
);
278 bool csum_and_copy_from_iter_full(void *addr
, size_t bytes
, __wsum
*csum
, struct iov_iter
*i
);
279 size_t hash_and_copy_to_iter(const void *addr
, size_t bytes
, void *hashp
,
282 int import_iovec(int type
, const struct iovec __user
* uvector
,
283 unsigned nr_segs
, unsigned fast_segs
,
284 struct iovec
**iov
, struct iov_iter
*i
);
288 int compat_import_iovec(int type
, const struct compat_iovec __user
* uvector
,
289 unsigned nr_segs
, unsigned fast_segs
,
290 struct iovec
**iov
, struct iov_iter
*i
);
293 int import_single_range(int type
, void __user
*buf
, size_t len
,
294 struct iovec
*iov
, struct iov_iter
*i
);
296 int iov_iter_for_each_range(struct iov_iter
*i
, size_t bytes
,
297 int (*f
)(struct kvec
*vec
, void *context
),