1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Berkeley style UIO structures - Alan Cox 1994.
8 #include <linux/kernel.h>
9 #include <linux/thread_info.h>
10 #include <uapi/linux/uio.h>
13 struct pipe_inode_info
;
16 void *iov_base
; /* and that should *never* hold a userland pointer */
36 const struct iovec
*iov
;
37 const struct kvec
*kvec
;
38 const struct bio_vec
*bvec
;
39 struct xarray
*xarray
;
40 struct pipe_inode_info
*pipe
;
43 unsigned long nr_segs
;
46 unsigned int start_head
;
53 static inline enum iter_type
iov_iter_type(const struct iov_iter
*i
)
58 static inline bool iter_is_iovec(const struct iov_iter
*i
)
60 return iov_iter_type(i
) == ITER_IOVEC
;
63 static inline bool iov_iter_is_kvec(const struct iov_iter
*i
)
65 return iov_iter_type(i
) == ITER_KVEC
;
68 static inline bool iov_iter_is_bvec(const struct iov_iter
*i
)
70 return iov_iter_type(i
) == ITER_BVEC
;
73 static inline bool iov_iter_is_pipe(const struct iov_iter
*i
)
75 return iov_iter_type(i
) == ITER_PIPE
;
78 static inline bool iov_iter_is_discard(const struct iov_iter
*i
)
80 return iov_iter_type(i
) == ITER_DISCARD
;
83 static inline bool iov_iter_is_xarray(const struct iov_iter
*i
)
85 return iov_iter_type(i
) == ITER_XARRAY
;
88 static inline unsigned char iov_iter_rw(const struct iov_iter
*i
)
90 return i
->data_source
? WRITE
: READ
;
94 * Total number of bytes covered by an iovec.
96 * NOTE that it is not safe to use this function until all the iovec's
97 * segment lengths have been validated. Because the individual lengths can
98 * overflow a size_t when added together.
100 static inline size_t iov_length(const struct iovec
*iov
, unsigned long nr_segs
)
105 for (seg
= 0; seg
< nr_segs
; seg
++)
106 ret
+= iov
[seg
].iov_len
;
110 static inline struct iovec
iov_iter_iovec(const struct iov_iter
*iter
)
112 return (struct iovec
) {
113 .iov_base
= iter
->iov
->iov_base
+ iter
->iov_offset
,
114 .iov_len
= min(iter
->count
,
115 iter
->iov
->iov_len
- iter
->iov_offset
),
119 size_t copy_page_from_iter_atomic(struct page
*page
, unsigned offset
,
120 size_t bytes
, struct iov_iter
*i
);
121 void iov_iter_advance(struct iov_iter
*i
, size_t bytes
);
122 void iov_iter_revert(struct iov_iter
*i
, size_t bytes
);
123 int iov_iter_fault_in_readable(const struct iov_iter
*i
, size_t bytes
);
124 size_t iov_iter_single_seg_count(const struct iov_iter
*i
);
125 size_t copy_page_to_iter(struct page
*page
, size_t offset
, size_t bytes
,
127 size_t copy_page_from_iter(struct page
*page
, size_t offset
, size_t bytes
,
130 size_t _copy_to_iter(const void *addr
, size_t bytes
, struct iov_iter
*i
);
131 size_t _copy_from_iter(void *addr
, size_t bytes
, struct iov_iter
*i
);
132 size_t _copy_from_iter_nocache(void *addr
, size_t bytes
, struct iov_iter
*i
);
134 static __always_inline __must_check
135 size_t copy_to_iter(const void *addr
, size_t bytes
, struct iov_iter
*i
)
137 if (unlikely(!check_copy_size(addr
, bytes
, true)))
140 return _copy_to_iter(addr
, bytes
, i
);
143 static __always_inline __must_check
144 size_t copy_from_iter(void *addr
, size_t bytes
, struct iov_iter
*i
)
146 if (unlikely(!check_copy_size(addr
, bytes
, false)))
149 return _copy_from_iter(addr
, bytes
, i
);
152 static __always_inline __must_check
153 bool copy_from_iter_full(void *addr
, size_t bytes
, struct iov_iter
*i
)
155 size_t copied
= copy_from_iter(addr
, bytes
, i
);
156 if (likely(copied
== bytes
))
158 iov_iter_revert(i
, copied
);
162 static __always_inline __must_check
163 size_t copy_from_iter_nocache(void *addr
, size_t bytes
, struct iov_iter
*i
)
165 if (unlikely(!check_copy_size(addr
, bytes
, false)))
168 return _copy_from_iter_nocache(addr
, bytes
, i
);
171 static __always_inline __must_check
172 bool copy_from_iter_full_nocache(void *addr
, size_t bytes
, struct iov_iter
*i
)
174 size_t copied
= copy_from_iter_nocache(addr
, bytes
, i
);
175 if (likely(copied
== bytes
))
177 iov_iter_revert(i
, copied
);
181 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
183 * Note, users like pmem that depend on the stricter semantics of
184 * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
185 * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
186 * destination is flushed from the cache on return.
188 size_t _copy_from_iter_flushcache(void *addr
, size_t bytes
, struct iov_iter
*i
);
190 #define _copy_from_iter_flushcache _copy_from_iter_nocache
193 #ifdef CONFIG_ARCH_HAS_COPY_MC
194 size_t _copy_mc_to_iter(const void *addr
, size_t bytes
, struct iov_iter
*i
);
196 #define _copy_mc_to_iter _copy_to_iter
199 static __always_inline __must_check
200 size_t copy_from_iter_flushcache(void *addr
, size_t bytes
, struct iov_iter
*i
)
202 if (unlikely(!check_copy_size(addr
, bytes
, false)))
205 return _copy_from_iter_flushcache(addr
, bytes
, i
);
208 static __always_inline __must_check
209 size_t copy_mc_to_iter(void *addr
, size_t bytes
, struct iov_iter
*i
)
211 if (unlikely(!check_copy_size(addr
, bytes
, true)))
214 return _copy_mc_to_iter(addr
, bytes
, i
);
217 size_t iov_iter_zero(size_t bytes
, struct iov_iter
*);
218 unsigned long iov_iter_alignment(const struct iov_iter
*i
);
219 unsigned long iov_iter_gap_alignment(const struct iov_iter
*i
);
220 void iov_iter_init(struct iov_iter
*i
, unsigned int direction
, const struct iovec
*iov
,
221 unsigned long nr_segs
, size_t count
);
222 void iov_iter_kvec(struct iov_iter
*i
, unsigned int direction
, const struct kvec
*kvec
,
223 unsigned long nr_segs
, size_t count
);
224 void iov_iter_bvec(struct iov_iter
*i
, unsigned int direction
, const struct bio_vec
*bvec
,
225 unsigned long nr_segs
, size_t count
);
226 void iov_iter_pipe(struct iov_iter
*i
, unsigned int direction
, struct pipe_inode_info
*pipe
,
228 void iov_iter_discard(struct iov_iter
*i
, unsigned int direction
, size_t count
);
229 void iov_iter_xarray(struct iov_iter
*i
, unsigned int direction
, struct xarray
*xarray
,
230 loff_t start
, size_t count
);
231 ssize_t
iov_iter_get_pages(struct iov_iter
*i
, struct page
**pages
,
232 size_t maxsize
, unsigned maxpages
, size_t *start
);
233 ssize_t
iov_iter_get_pages_alloc(struct iov_iter
*i
, struct page
***pages
,
234 size_t maxsize
, size_t *start
);
235 int iov_iter_npages(const struct iov_iter
*i
, int maxpages
);
237 const void *dup_iter(struct iov_iter
*new, struct iov_iter
*old
, gfp_t flags
);
239 static inline size_t iov_iter_count(const struct iov_iter
*i
)
245 * Cap the iov_iter by given limit; note that the second argument is
246 * *not* the new size - it's upper limit for such. Passing it a value
247 * greater than the amount of data in iov_iter is fine - it'll just do
248 * nothing in that case.
250 static inline void iov_iter_truncate(struct iov_iter
*i
, u64 count
)
253 * count doesn't have to fit in size_t - comparison extends both
254 * operands to u64 here and any value that would be truncated by
255 * conversion in assignement is by definition greater than all
256 * values of size_t, including old i->count.
258 if (i
->count
> count
) {
259 i
->truncated
+= i
->count
- count
;
265 * reexpand a previously truncated iterator; count must be no more than how much
268 static inline void iov_iter_reexpand(struct iov_iter
*i
, size_t count
)
270 i
->truncated
-= count
- i
->count
;
279 size_t csum_and_copy_to_iter(const void *addr
, size_t bytes
, void *csstate
, struct iov_iter
*i
);
280 size_t csum_and_copy_from_iter(void *addr
, size_t bytes
, __wsum
*csum
, struct iov_iter
*i
);
282 static __always_inline __must_check
283 bool csum_and_copy_from_iter_full(void *addr
, size_t bytes
,
284 __wsum
*csum
, struct iov_iter
*i
)
286 size_t copied
= csum_and_copy_from_iter(addr
, bytes
, csum
, i
);
287 if (likely(copied
== bytes
))
289 iov_iter_revert(i
, copied
);
292 size_t hash_and_copy_to_iter(const void *addr
, size_t bytes
, void *hashp
,
295 struct iovec
*iovec_from_user(const struct iovec __user
*uvector
,
296 unsigned long nr_segs
, unsigned long fast_segs
,
297 struct iovec
*fast_iov
, bool compat
);
298 ssize_t
import_iovec(int type
, const struct iovec __user
*uvec
,
299 unsigned nr_segs
, unsigned fast_segs
, struct iovec
**iovp
,
301 ssize_t
__import_iovec(int type
, const struct iovec __user
*uvec
,
302 unsigned nr_segs
, unsigned fast_segs
, struct iovec
**iovp
,
303 struct iov_iter
*i
, bool compat
);
304 int import_single_range(int type
, void __user
*buf
, size_t len
,
305 struct iovec
*iov
, struct iov_iter
*i
);