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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
4f18cd31 | 2 | #include <linux/export.h> |
2f8b5444 | 3 | #include <linux/bvec.h> |
4d0e9df5 | 4 | #include <linux/fault-inject-usercopy.h> |
4f18cd31 AV |
5 | #include <linux/uio.h> |
6 | #include <linux/pagemap.h> | |
28961998 | 7 | #include <linux/highmem.h> |
91f79c43 AV |
8 | #include <linux/slab.h> |
9 | #include <linux/vmalloc.h> | |
241699cd | 10 | #include <linux/splice.h> |
bfdc5970 | 11 | #include <linux/compat.h> |
d05f4435 | 12 | #include <linux/scatterlist.h> |
d0ef4c36 | 13 | #include <linux/instrumented.h> |
f1982740 | 14 | #include <linux/iov_iter.h> |
4f18cd31 | 15 | |
f1982740 DH |
16 | static __always_inline |
17 | size_t copy_to_user_iter(void __user *iter_to, size_t progress, | |
18 | size_t len, void *from, void *priv2) | |
09fc68dc | 19 | { |
4d0e9df5 | 20 | if (should_fail_usercopy()) |
f1982740 DH |
21 | return len; |
22 | if (access_ok(iter_to, len)) { | |
23 | from += progress; | |
24 | instrument_copy_to_user(iter_to, from, len); | |
25 | len = raw_copy_to_user(iter_to, from, len); | |
09fc68dc | 26 | } |
f1982740 | 27 | return len; |
09fc68dc AV |
28 | } |
29 | ||
f1982740 DH |
30 | static __always_inline |
31 | size_t copy_to_user_iter_nofault(void __user *iter_to, size_t progress, | |
32 | size_t len, void *from, void *priv2) | |
4f80818b | 33 | { |
f1982740 | 34 | ssize_t res; |
4f80818b LS |
35 | |
36 | if (should_fail_usercopy()) | |
f1982740 | 37 | return len; |
4f80818b | 38 | |
f1982740 DH |
39 | from += progress; |
40 | res = copy_to_user_nofault(iter_to, from, len); | |
41 | return res < 0 ? len : res; | |
4f80818b LS |
42 | } |
43 | ||
f1982740 DH |
44 | static __always_inline |
45 | size_t copy_from_user_iter(void __user *iter_from, size_t progress, | |
46 | size_t len, void *to, void *priv2) | |
09fc68dc | 47 | { |
f1982740 | 48 | size_t res = len; |
33b75c1d | 49 | |
4d0e9df5 | 50 | if (should_fail_usercopy()) |
f1982740 DH |
51 | return len; |
52 | if (access_ok(iter_from, len)) { | |
53 | to += progress; | |
54 | instrument_copy_from_user_before(to, iter_from, len); | |
55 | res = raw_copy_from_user(to, iter_from, len); | |
56 | instrument_copy_from_user_after(to, iter_from, len, res); | |
09fc68dc | 57 | } |
33b75c1d | 58 | return res; |
09fc68dc AV |
59 | } |
60 | ||
f1982740 DH |
61 | static __always_inline |
62 | size_t memcpy_to_iter(void *iter_to, size_t progress, | |
63 | size_t len, void *from, void *priv2) | |
64 | { | |
65 | memcpy(iter_to, from + progress, len); | |
66 | return 0; | |
67 | } | |
68 | ||
69 | static __always_inline | |
70 | size_t memcpy_from_iter(void *iter_from, size_t progress, | |
71 | size_t len, void *to, void *priv2) | |
72 | { | |
73 | memcpy(to + progress, iter_from, len); | |
74 | return 0; | |
75 | } | |
76 | ||
171a0203 | 77 | /* |
a6294593 AG |
78 | * fault_in_iov_iter_readable - fault in iov iterator for reading |
79 | * @i: iterator | |
80 | * @size: maximum length | |
81 | * | |
171a0203 | 82 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of |
a6294593 AG |
83 | * @size. For each iovec, fault in each page that constitutes the iovec. |
84 | * | |
85 | * Returns the number of bytes not faulted in (like copy_to_user() and | |
86 | * copy_from_user()). | |
171a0203 | 87 | * |
a6294593 | 88 | * Always returns 0 for non-userspace iterators. |
171a0203 | 89 | */ |
a6294593 | 90 | size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size) |
171a0203 | 91 | { |
fcb14cb1 AV |
92 | if (iter_is_ubuf(i)) { |
93 | size_t n = min(size, iov_iter_count(i)); | |
94 | n -= fault_in_readable(i->ubuf + i->iov_offset, n); | |
95 | return size - n; | |
96 | } else if (iter_is_iovec(i)) { | |
a6294593 | 97 | size_t count = min(size, iov_iter_count(i)); |
8409a0d2 AV |
98 | const struct iovec *p; |
99 | size_t skip; | |
100 | ||
a6294593 | 101 | size -= count; |
de4f5fed | 102 | for (p = iter_iov(i), skip = i->iov_offset; count; p++, skip = 0) { |
a6294593 AG |
103 | size_t len = min(count, p->iov_len - skip); |
104 | size_t ret; | |
8409a0d2 AV |
105 | |
106 | if (unlikely(!len)) | |
107 | continue; | |
a6294593 AG |
108 | ret = fault_in_readable(p->iov_base + skip, len); |
109 | count -= len - ret; | |
110 | if (ret) | |
111 | break; | |
8409a0d2 | 112 | } |
a6294593 | 113 | return count + size; |
171a0203 AA |
114 | } |
115 | return 0; | |
116 | } | |
a6294593 | 117 | EXPORT_SYMBOL(fault_in_iov_iter_readable); |
171a0203 | 118 | |
cdd591fc AG |
119 | /* |
120 | * fault_in_iov_iter_writeable - fault in iov iterator for writing | |
121 | * @i: iterator | |
122 | * @size: maximum length | |
123 | * | |
124 | * Faults in the iterator using get_user_pages(), i.e., without triggering | |
125 | * hardware page faults. This is primarily useful when we already know that | |
126 | * some or all of the pages in @i aren't in memory. | |
127 | * | |
128 | * Returns the number of bytes not faulted in, like copy_to_user() and | |
129 | * copy_from_user(). | |
130 | * | |
131 | * Always returns 0 for non-user-space iterators. | |
132 | */ | |
133 | size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size) | |
134 | { | |
fcb14cb1 AV |
135 | if (iter_is_ubuf(i)) { |
136 | size_t n = min(size, iov_iter_count(i)); | |
137 | n -= fault_in_safe_writeable(i->ubuf + i->iov_offset, n); | |
138 | return size - n; | |
139 | } else if (iter_is_iovec(i)) { | |
cdd591fc AG |
140 | size_t count = min(size, iov_iter_count(i)); |
141 | const struct iovec *p; | |
142 | size_t skip; | |
143 | ||
144 | size -= count; | |
de4f5fed | 145 | for (p = iter_iov(i), skip = i->iov_offset; count; p++, skip = 0) { |
cdd591fc AG |
146 | size_t len = min(count, p->iov_len - skip); |
147 | size_t ret; | |
148 | ||
149 | if (unlikely(!len)) | |
150 | continue; | |
151 | ret = fault_in_safe_writeable(p->iov_base + skip, len); | |
152 | count -= len - ret; | |
153 | if (ret) | |
154 | break; | |
155 | } | |
156 | return count + size; | |
157 | } | |
158 | return 0; | |
159 | } | |
160 | EXPORT_SYMBOL(fault_in_iov_iter_writeable); | |
161 | ||
aa563d7b | 162 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
163 | const struct iovec *iov, unsigned long nr_segs, |
164 | size_t count) | |
165 | { | |
aa563d7b | 166 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
167 | *i = (struct iov_iter) { |
168 | .iter_type = ITER_IOVEC, | |
3337ab08 | 169 | .nofault = false, |
8cd54c1c | 170 | .data_source = direction, |
de4f5fed | 171 | .__iov = iov, |
8cd54c1c AV |
172 | .nr_segs = nr_segs, |
173 | .iov_offset = 0, | |
174 | .count = count | |
175 | }; | |
71d8e532 AV |
176 | } |
177 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 178 | |
aa28de27 | 179 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 180 | { |
a41dad90 AV |
181 | if (WARN_ON_ONCE(i->data_source)) |
182 | return 0; | |
fcb14cb1 | 183 | if (user_backed_iter(i)) |
09fc68dc | 184 | might_fault(); |
f1982740 DH |
185 | return iterate_and_advance(i, bytes, (void *)addr, |
186 | copy_to_user_iter, memcpy_to_iter); | |
c35e0248 | 187 | } |
aa28de27 | 188 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 189 | |
ec6347bb | 190 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
f1982740 DH |
191 | static __always_inline |
192 | size_t copy_to_user_iter_mc(void __user *iter_to, size_t progress, | |
193 | size_t len, void *from, void *priv2) | |
8780356e | 194 | { |
f1982740 DH |
195 | if (access_ok(iter_to, len)) { |
196 | from += progress; | |
197 | instrument_copy_to_user(iter_to, from, len); | |
198 | len = copy_mc_to_user(iter_to, from, len); | |
8780356e | 199 | } |
f1982740 DH |
200 | return len; |
201 | } | |
202 | ||
203 | static __always_inline | |
204 | size_t memcpy_to_iter_mc(void *iter_to, size_t progress, | |
205 | size_t len, void *from, void *priv2) | |
206 | { | |
207 | return copy_mc_to_kernel(iter_to, from + progress, len); | |
8780356e DW |
208 | } |
209 | ||
bf3eeb9b | 210 | /** |
ec6347bb | 211 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
bf3eeb9b DW |
212 | * @addr: source kernel address |
213 | * @bytes: total transfer length | |
44e55997 | 214 | * @i: destination iterator |
bf3eeb9b | 215 | * |
ec6347bb DW |
216 | * The pmem driver deploys this for the dax operation |
217 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the | |
218 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes | |
219 | * successfully copied. | |
bf3eeb9b | 220 | * |
ec6347bb | 221 | * The main differences between this and typical _copy_to_iter(). |
bf3eeb9b DW |
222 | * |
223 | * * Typical tail/residue handling after a fault retries the copy | |
224 | * byte-by-byte until the fault happens again. Re-triggering machine | |
225 | * checks is potentially fatal so the implementation uses source | |
226 | * alignment and poison alignment assumptions to avoid re-triggering | |
227 | * hardware exceptions. | |
228 | * | |
3fc40265 DH |
229 | * * ITER_KVEC and ITER_BVEC can return short copies. Compare to |
230 | * copy_to_iter() where only ITER_IOVEC attempts might return a short copy. | |
44e55997 RD |
231 | * |
232 | * Return: number of bytes copied (may be %0) | |
bf3eeb9b | 233 | */ |
ec6347bb | 234 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
8780356e | 235 | { |
a41dad90 AV |
236 | if (WARN_ON_ONCE(i->data_source)) |
237 | return 0; | |
fcb14cb1 | 238 | if (user_backed_iter(i)) |
8780356e | 239 | might_fault(); |
f1982740 DH |
240 | return iterate_and_advance(i, bytes, (void *)addr, |
241 | copy_to_user_iter_mc, memcpy_to_iter_mc); | |
8780356e | 242 | } |
ec6347bb DW |
243 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
244 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 245 | |
c9eec08b DH |
246 | static __always_inline |
247 | size_t __copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) | |
248 | { | |
c9eec08b DH |
249 | return iterate_and_advance(i, bytes, addr, |
250 | copy_from_user_iter, memcpy_from_iter); | |
245f0922 KW |
251 | } |
252 | ||
aa28de27 | 253 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 254 | { |
a41dad90 | 255 | if (WARN_ON_ONCE(!i->data_source)) |
241699cd | 256 | return 0; |
a41dad90 | 257 | |
fcb14cb1 | 258 | if (user_backed_iter(i)) |
09fc68dc | 259 | might_fault(); |
c9eec08b | 260 | return __copy_from_iter(addr, bytes, i); |
c35e0248 | 261 | } |
aa28de27 | 262 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 263 | |
f1982740 DH |
264 | static __always_inline |
265 | size_t copy_from_user_iter_nocache(void __user *iter_from, size_t progress, | |
266 | size_t len, void *to, void *priv2) | |
267 | { | |
268 | return __copy_from_user_inatomic_nocache(to + progress, iter_from, len); | |
269 | } | |
270 | ||
aa28de27 | 271 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 | 272 | { |
a41dad90 | 273 | if (WARN_ON_ONCE(!i->data_source)) |
241699cd | 274 | return 0; |
a41dad90 | 275 | |
f1982740 DH |
276 | return iterate_and_advance(i, bytes, addr, |
277 | copy_from_user_iter_nocache, | |
278 | memcpy_from_iter); | |
aa583096 | 279 | } |
aa28de27 | 280 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 281 | |
0aed55af | 282 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
f1982740 DH |
283 | static __always_inline |
284 | size_t copy_from_user_iter_flushcache(void __user *iter_from, size_t progress, | |
285 | size_t len, void *to, void *priv2) | |
286 | { | |
287 | return __copy_from_user_flushcache(to + progress, iter_from, len); | |
288 | } | |
289 | ||
290 | static __always_inline | |
291 | size_t memcpy_from_iter_flushcache(void *iter_from, size_t progress, | |
292 | size_t len, void *to, void *priv2) | |
293 | { | |
294 | memcpy_flushcache(to + progress, iter_from, len); | |
295 | return 0; | |
296 | } | |
297 | ||
abd08d7d DW |
298 | /** |
299 | * _copy_from_iter_flushcache - write destination through cpu cache | |
300 | * @addr: destination kernel address | |
301 | * @bytes: total transfer length | |
44e55997 | 302 | * @i: source iterator |
abd08d7d DW |
303 | * |
304 | * The pmem driver arranges for filesystem-dax to use this facility via | |
305 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
306 | * are flushed through the CPU cache. It is differentiated from | |
307 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
308 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
309 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
310 | * instructions that strand dirty-data in the cache. | |
44e55997 RD |
311 | * |
312 | * Return: number of bytes copied (may be %0) | |
abd08d7d | 313 | */ |
6a37e940 | 314 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af | 315 | { |
a41dad90 | 316 | if (WARN_ON_ONCE(!i->data_source)) |
0aed55af | 317 | return 0; |
a41dad90 | 318 | |
f1982740 DH |
319 | return iterate_and_advance(i, bytes, addr, |
320 | copy_from_user_iter_flushcache, | |
321 | memcpy_from_iter_flushcache); | |
0aed55af | 322 | } |
6a37e940 | 323 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
324 | #endif |
325 | ||
72e809ed AV |
326 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
327 | { | |
6daef95b ED |
328 | struct page *head; |
329 | size_t v = n + offset; | |
330 | ||
331 | /* | |
332 | * The general case needs to access the page order in order | |
333 | * to compute the page size. | |
334 | * However, we mostly deal with order-0 pages and thus can | |
335 | * avoid a possible cache line miss for requests that fit all | |
336 | * page orders. | |
337 | */ | |
338 | if (n <= v && v <= PAGE_SIZE) | |
339 | return true; | |
340 | ||
341 | head = compound_head(page); | |
342 | v += (page - head) << PAGE_SHIFT; | |
a90bcb86 | 343 | |
40a86061 AV |
344 | if (WARN_ON(n > v || v > page_size(head))) |
345 | return false; | |
346 | return true; | |
72e809ed | 347 | } |
cbbd26b8 | 348 | |
08aa6479 AV |
349 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
350 | struct iov_iter *i) | |
351 | { | |
352 | size_t res = 0; | |
40a86061 | 353 | if (!page_copy_sane(page, offset, bytes)) |
08aa6479 | 354 | return 0; |
a41dad90 AV |
355 | if (WARN_ON_ONCE(i->data_source)) |
356 | return 0; | |
08aa6479 AV |
357 | page += offset / PAGE_SIZE; // first subpage |
358 | offset %= PAGE_SIZE; | |
359 | while (1) { | |
f0f6b614 AV |
360 | void *kaddr = kmap_local_page(page); |
361 | size_t n = min(bytes, (size_t)PAGE_SIZE - offset); | |
362 | n = _copy_to_iter(kaddr + offset, n, i); | |
363 | kunmap_local(kaddr); | |
08aa6479 AV |
364 | res += n; |
365 | bytes -= n; | |
366 | if (!bytes || !n) | |
367 | break; | |
368 | offset += n; | |
369 | if (offset == PAGE_SIZE) { | |
370 | page++; | |
371 | offset = 0; | |
372 | } | |
373 | } | |
374 | return res; | |
375 | } | |
62a8067a AV |
376 | EXPORT_SYMBOL(copy_page_to_iter); |
377 | ||
4f80818b LS |
378 | size_t copy_page_to_iter_nofault(struct page *page, unsigned offset, size_t bytes, |
379 | struct iov_iter *i) | |
380 | { | |
381 | size_t res = 0; | |
382 | ||
383 | if (!page_copy_sane(page, offset, bytes)) | |
384 | return 0; | |
385 | if (WARN_ON_ONCE(i->data_source)) | |
386 | return 0; | |
4f80818b LS |
387 | page += offset / PAGE_SIZE; // first subpage |
388 | offset %= PAGE_SIZE; | |
389 | while (1) { | |
390 | void *kaddr = kmap_local_page(page); | |
391 | size_t n = min(bytes, (size_t)PAGE_SIZE - offset); | |
392 | ||
fe2c34ba | 393 | n = iterate_and_advance(i, n, kaddr + offset, |
f1982740 DH |
394 | copy_to_user_iter_nofault, |
395 | memcpy_to_iter); | |
4f80818b LS |
396 | kunmap_local(kaddr); |
397 | res += n; | |
398 | bytes -= n; | |
399 | if (!bytes || !n) | |
400 | break; | |
401 | offset += n; | |
402 | if (offset == PAGE_SIZE) { | |
403 | page++; | |
404 | offset = 0; | |
405 | } | |
406 | } | |
407 | return res; | |
408 | } | |
409 | EXPORT_SYMBOL(copy_page_to_iter_nofault); | |
410 | ||
62a8067a AV |
411 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
412 | struct iov_iter *i) | |
413 | { | |
c03f05f1 AV |
414 | size_t res = 0; |
415 | if (!page_copy_sane(page, offset, bytes)) | |
416 | return 0; | |
417 | page += offset / PAGE_SIZE; // first subpage | |
418 | offset %= PAGE_SIZE; | |
419 | while (1) { | |
55ca375c | 420 | void *kaddr = kmap_local_page(page); |
c03f05f1 AV |
421 | size_t n = min(bytes, (size_t)PAGE_SIZE - offset); |
422 | n = _copy_from_iter(kaddr + offset, n, i); | |
55ca375c | 423 | kunmap_local(kaddr); |
c03f05f1 AV |
424 | res += n; |
425 | bytes -= n; | |
426 | if (!bytes || !n) | |
427 | break; | |
428 | offset += n; | |
429 | if (offset == PAGE_SIZE) { | |
430 | page++; | |
431 | offset = 0; | |
432 | } | |
28f38db7 | 433 | } |
c03f05f1 | 434 | return res; |
62a8067a AV |
435 | } |
436 | EXPORT_SYMBOL(copy_page_from_iter); | |
437 | ||
f1982740 DH |
438 | static __always_inline |
439 | size_t zero_to_user_iter(void __user *iter_to, size_t progress, | |
440 | size_t len, void *priv, void *priv2) | |
c35e0248 | 441 | { |
f1982740 DH |
442 | return clear_user(iter_to, len); |
443 | } | |
8442fa46 | 444 | |
f1982740 DH |
445 | static __always_inline |
446 | size_t zero_to_iter(void *iter_to, size_t progress, | |
447 | size_t len, void *priv, void *priv2) | |
448 | { | |
449 | memset(iter_to, 0, len); | |
450 | return 0; | |
451 | } | |
452 | ||
453 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) | |
454 | { | |
455 | return iterate_and_advance(i, bytes, NULL, | |
456 | zero_to_user_iter, zero_to_iter); | |
c35e0248 MW |
457 | } |
458 | EXPORT_SYMBOL(iov_iter_zero); | |
459 | ||
1b030698 | 460 | size_t copy_page_from_iter_atomic(struct page *page, size_t offset, |
908a1ad8 | 461 | size_t bytes, struct iov_iter *i) |
62a8067a | 462 | { |
908a1ad8 | 463 | size_t n, copied = 0; |
f7f9a0c8 MWO |
464 | |
465 | if (!page_copy_sane(page, offset, bytes)) | |
72e809ed | 466 | return 0; |
f7f9a0c8 | 467 | if (WARN_ON_ONCE(!i->data_source)) |
241699cd | 468 | return 0; |
f7f9a0c8 | 469 | |
908a1ad8 MWO |
470 | do { |
471 | char *p; | |
f7f9a0c8 | 472 | |
908a1ad8 MWO |
473 | n = bytes - copied; |
474 | if (PageHighMem(page)) { | |
475 | page += offset / PAGE_SIZE; | |
476 | offset %= PAGE_SIZE; | |
477 | n = min_t(size_t, n, PAGE_SIZE - offset); | |
478 | } | |
479 | ||
480 | p = kmap_atomic(page) + offset; | |
c9eec08b | 481 | n = __copy_from_iter(p, n, i); |
908a1ad8 MWO |
482 | kunmap_atomic(p); |
483 | copied += n; | |
484 | offset += n; | |
485 | } while (PageHighMem(page) && copied != bytes && n > 0); | |
486 | ||
487 | return copied; | |
62a8067a | 488 | } |
f0b65f39 | 489 | EXPORT_SYMBOL(copy_page_from_iter_atomic); |
62a8067a | 490 | |
54c8195b PB |
491 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
492 | { | |
18fa9af7 | 493 | const struct bio_vec *bvec, *end; |
54c8195b | 494 | |
18fa9af7 AV |
495 | if (!i->count) |
496 | return; | |
497 | i->count -= size; | |
498 | ||
499 | size += i->iov_offset; | |
54c8195b | 500 | |
18fa9af7 AV |
501 | for (bvec = i->bvec, end = bvec + i->nr_segs; bvec < end; bvec++) { |
502 | if (likely(size < bvec->bv_len)) | |
503 | break; | |
504 | size -= bvec->bv_len; | |
505 | } | |
506 | i->iov_offset = size; | |
507 | i->nr_segs -= bvec - i->bvec; | |
508 | i->bvec = bvec; | |
54c8195b PB |
509 | } |
510 | ||
185ac4d4 AV |
511 | static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) |
512 | { | |
513 | const struct iovec *iov, *end; | |
514 | ||
515 | if (!i->count) | |
516 | return; | |
517 | i->count -= size; | |
518 | ||
519 | size += i->iov_offset; // from beginning of current segment | |
de4f5fed | 520 | for (iov = iter_iov(i), end = iov + i->nr_segs; iov < end; iov++) { |
185ac4d4 AV |
521 | if (likely(size < iov->iov_len)) |
522 | break; | |
523 | size -= iov->iov_len; | |
524 | } | |
525 | i->iov_offset = size; | |
de4f5fed JA |
526 | i->nr_segs -= iov - iter_iov(i); |
527 | i->__iov = iov; | |
185ac4d4 AV |
528 | } |
529 | ||
db0aa2e9 DH |
530 | static void iov_iter_folioq_advance(struct iov_iter *i, size_t size) |
531 | { | |
532 | const struct folio_queue *folioq = i->folioq; | |
533 | unsigned int slot = i->folioq_slot; | |
534 | ||
535 | if (!i->count) | |
536 | return; | |
537 | i->count -= size; | |
538 | ||
539 | if (slot >= folioq_nr_slots(folioq)) { | |
540 | folioq = folioq->next; | |
541 | slot = 0; | |
542 | } | |
543 | ||
544 | size += i->iov_offset; /* From beginning of current segment. */ | |
545 | do { | |
546 | size_t fsize = folioq_folio_size(folioq, slot); | |
547 | ||
548 | if (likely(size < fsize)) | |
549 | break; | |
550 | size -= fsize; | |
551 | slot++; | |
552 | if (slot >= folioq_nr_slots(folioq) && folioq->next) { | |
553 | folioq = folioq->next; | |
554 | slot = 0; | |
555 | } | |
556 | } while (size); | |
557 | ||
558 | i->iov_offset = size; | |
559 | i->folioq_slot = slot; | |
560 | i->folioq = folioq; | |
561 | } | |
562 | ||
62a8067a AV |
563 | void iov_iter_advance(struct iov_iter *i, size_t size) |
564 | { | |
3b3fc051 AV |
565 | if (unlikely(i->count < size)) |
566 | size = i->count; | |
fcb14cb1 AV |
567 | if (likely(iter_is_ubuf(i)) || unlikely(iov_iter_is_xarray(i))) { |
568 | i->iov_offset += size; | |
569 | i->count -= size; | |
570 | } else if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { | |
185ac4d4 AV |
571 | /* iovec and kvec have identical layouts */ |
572 | iov_iter_iovec_advance(i, size); | |
573 | } else if (iov_iter_is_bvec(i)) { | |
574 | iov_iter_bvec_advance(i, size); | |
db0aa2e9 DH |
575 | } else if (iov_iter_is_folioq(i)) { |
576 | iov_iter_folioq_advance(i, size); | |
185ac4d4 AV |
577 | } else if (iov_iter_is_discard(i)) { |
578 | i->count -= size; | |
54c8195b | 579 | } |
62a8067a AV |
580 | } |
581 | EXPORT_SYMBOL(iov_iter_advance); | |
582 | ||
db0aa2e9 DH |
583 | static void iov_iter_folioq_revert(struct iov_iter *i, size_t unroll) |
584 | { | |
585 | const struct folio_queue *folioq = i->folioq; | |
586 | unsigned int slot = i->folioq_slot; | |
587 | ||
588 | for (;;) { | |
589 | size_t fsize; | |
590 | ||
591 | if (slot == 0) { | |
592 | folioq = folioq->prev; | |
593 | slot = folioq_nr_slots(folioq); | |
594 | } | |
595 | slot--; | |
596 | ||
597 | fsize = folioq_folio_size(folioq, slot); | |
598 | if (unroll <= fsize) { | |
599 | i->iov_offset = fsize - unroll; | |
600 | break; | |
601 | } | |
602 | unroll -= fsize; | |
603 | } | |
604 | ||
605 | i->folioq_slot = slot; | |
606 | i->folioq = folioq; | |
607 | } | |
608 | ||
27c0e374 AV |
609 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
610 | { | |
611 | if (!unroll) | |
612 | return; | |
5b47d59a AV |
613 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
614 | return; | |
27c0e374 | 615 | i->count += unroll; |
9ea9ce04 DH |
616 | if (unlikely(iov_iter_is_discard(i))) |
617 | return; | |
27c0e374 AV |
618 | if (unroll <= i->iov_offset) { |
619 | i->iov_offset -= unroll; | |
620 | return; | |
621 | } | |
622 | unroll -= i->iov_offset; | |
fcb14cb1 | 623 | if (iov_iter_is_xarray(i) || iter_is_ubuf(i)) { |
7ff50620 DH |
624 | BUG(); /* We should never go beyond the start of the specified |
625 | * range since we might then be straying into pages that | |
626 | * aren't pinned. | |
627 | */ | |
628 | } else if (iov_iter_is_bvec(i)) { | |
27c0e374 AV |
629 | const struct bio_vec *bvec = i->bvec; |
630 | while (1) { | |
631 | size_t n = (--bvec)->bv_len; | |
632 | i->nr_segs++; | |
633 | if (unroll <= n) { | |
634 | i->bvec = bvec; | |
635 | i->iov_offset = n - unroll; | |
636 | return; | |
637 | } | |
638 | unroll -= n; | |
639 | } | |
db0aa2e9 DH |
640 | } else if (iov_iter_is_folioq(i)) { |
641 | i->iov_offset = 0; | |
642 | iov_iter_folioq_revert(i, unroll); | |
27c0e374 | 643 | } else { /* same logics for iovec and kvec */ |
de4f5fed | 644 | const struct iovec *iov = iter_iov(i); |
27c0e374 AV |
645 | while (1) { |
646 | size_t n = (--iov)->iov_len; | |
647 | i->nr_segs++; | |
648 | if (unroll <= n) { | |
de4f5fed | 649 | i->__iov = iov; |
27c0e374 AV |
650 | i->iov_offset = n - unroll; |
651 | return; | |
652 | } | |
653 | unroll -= n; | |
654 | } | |
655 | } | |
656 | } | |
657 | EXPORT_SYMBOL(iov_iter_revert); | |
658 | ||
62a8067a AV |
659 | /* |
660 | * Return the count of just the current iov_iter segment. | |
661 | */ | |
662 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
663 | { | |
28f38db7 AV |
664 | if (i->nr_segs > 1) { |
665 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
de4f5fed | 666 | return min(i->count, iter_iov(i)->iov_len - i->iov_offset); |
28f38db7 AV |
667 | if (iov_iter_is_bvec(i)) |
668 | return min(i->count, i->bvec->bv_len - i->iov_offset); | |
669 | } | |
db0aa2e9 DH |
670 | if (unlikely(iov_iter_is_folioq(i))) |
671 | return !i->count ? 0 : | |
672 | umin(folioq_folio_size(i->folioq, i->folioq_slot), i->count); | |
28f38db7 | 673 | return i->count; |
62a8067a AV |
674 | } |
675 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
676 | ||
aa563d7b | 677 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 678 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
679 | size_t count) |
680 | { | |
aa563d7b | 681 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
682 | *i = (struct iov_iter){ |
683 | .iter_type = ITER_KVEC, | |
684 | .data_source = direction, | |
685 | .kvec = kvec, | |
686 | .nr_segs = nr_segs, | |
687 | .iov_offset = 0, | |
688 | .count = count | |
689 | }; | |
abb78f87 AV |
690 | } |
691 | EXPORT_SYMBOL(iov_iter_kvec); | |
692 | ||
aa563d7b | 693 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
694 | const struct bio_vec *bvec, unsigned long nr_segs, |
695 | size_t count) | |
696 | { | |
aa563d7b | 697 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
698 | *i = (struct iov_iter){ |
699 | .iter_type = ITER_BVEC, | |
700 | .data_source = direction, | |
701 | .bvec = bvec, | |
702 | .nr_segs = nr_segs, | |
703 | .iov_offset = 0, | |
704 | .count = count | |
705 | }; | |
05afcb77 AV |
706 | } |
707 | EXPORT_SYMBOL(iov_iter_bvec); | |
708 | ||
db0aa2e9 DH |
709 | /** |
710 | * iov_iter_folio_queue - Initialise an I/O iterator to use the folios in a folio queue | |
711 | * @i: The iterator to initialise. | |
712 | * @direction: The direction of the transfer. | |
713 | * @folioq: The starting point in the folio queue. | |
714 | * @first_slot: The first slot in the folio queue to use | |
715 | * @offset: The offset into the folio in the first slot to start at | |
716 | * @count: The size of the I/O buffer in bytes. | |
717 | * | |
718 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
719 | * inode or to inject data into those pages. The pages *must* be prevented | |
720 | * from evaporation, either by taking a ref on them or locking them by the | |
721 | * caller. | |
722 | */ | |
723 | void iov_iter_folio_queue(struct iov_iter *i, unsigned int direction, | |
724 | const struct folio_queue *folioq, unsigned int first_slot, | |
725 | unsigned int offset, size_t count) | |
726 | { | |
727 | BUG_ON(direction & ~1); | |
728 | *i = (struct iov_iter) { | |
729 | .iter_type = ITER_FOLIOQ, | |
730 | .data_source = direction, | |
731 | .folioq = folioq, | |
732 | .folioq_slot = first_slot, | |
733 | .count = count, | |
734 | .iov_offset = offset, | |
735 | }; | |
736 | } | |
737 | EXPORT_SYMBOL(iov_iter_folio_queue); | |
738 | ||
7ff50620 DH |
739 | /** |
740 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray | |
741 | * @i: The iterator to initialise. | |
742 | * @direction: The direction of the transfer. | |
743 | * @xarray: The xarray to access. | |
744 | * @start: The start file position. | |
745 | * @count: The size of the I/O buffer in bytes. | |
746 | * | |
747 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
748 | * inode or to inject data into those pages. The pages *must* be prevented | |
749 | * from evaporation, either by taking a ref on them or locking them by the | |
750 | * caller. | |
751 | */ | |
752 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, | |
753 | struct xarray *xarray, loff_t start, size_t count) | |
754 | { | |
755 | BUG_ON(direction & ~1); | |
8cd54c1c AV |
756 | *i = (struct iov_iter) { |
757 | .iter_type = ITER_XARRAY, | |
758 | .data_source = direction, | |
759 | .xarray = xarray, | |
760 | .xarray_start = start, | |
761 | .count = count, | |
762 | .iov_offset = 0 | |
763 | }; | |
7ff50620 DH |
764 | } |
765 | EXPORT_SYMBOL(iov_iter_xarray); | |
766 | ||
9ea9ce04 DH |
767 | /** |
768 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
769 | * @i: The iterator to initialise. | |
770 | * @direction: The direction of the transfer. | |
771 | * @count: The size of the I/O buffer in bytes. | |
772 | * | |
773 | * Set up an I/O iterator that just discards everything that's written to it. | |
774 | * It's only available as a READ iterator. | |
775 | */ | |
776 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
777 | { | |
778 | BUG_ON(direction != READ); | |
8cd54c1c AV |
779 | *i = (struct iov_iter){ |
780 | .iter_type = ITER_DISCARD, | |
781 | .data_source = false, | |
782 | .count = count, | |
783 | .iov_offset = 0 | |
784 | }; | |
9ea9ce04 DH |
785 | } |
786 | EXPORT_SYMBOL(iov_iter_discard); | |
787 | ||
cfa320f7 KB |
788 | static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask, |
789 | unsigned len_mask) | |
790 | { | |
2263639f | 791 | const struct iovec *iov = iter_iov(i); |
cfa320f7 KB |
792 | size_t size = i->count; |
793 | size_t skip = i->iov_offset; | |
cfa320f7 | 794 | |
2263639f | 795 | do { |
de4f5fed | 796 | size_t len = iov->iov_len - skip; |
cfa320f7 KB |
797 | |
798 | if (len > size) | |
799 | len = size; | |
800 | if (len & len_mask) | |
801 | return false; | |
de4f5fed | 802 | if ((unsigned long)(iov->iov_base + skip) & addr_mask) |
cfa320f7 KB |
803 | return false; |
804 | ||
2263639f | 805 | iov++; |
cfa320f7 | 806 | size -= len; |
2263639f JA |
807 | skip = 0; |
808 | } while (size); | |
809 | ||
cfa320f7 KB |
810 | return true; |
811 | } | |
812 | ||
813 | static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask, | |
814 | unsigned len_mask) | |
815 | { | |
2263639f | 816 | const struct bio_vec *bvec = i->bvec; |
cfa320f7 | 817 | unsigned skip = i->iov_offset; |
2263639f | 818 | size_t size = i->count; |
cfa320f7 | 819 | |
2263639f JA |
820 | do { |
821 | size_t len = bvec->bv_len; | |
cfa320f7 KB |
822 | |
823 | if (len > size) | |
824 | len = size; | |
825 | if (len & len_mask) | |
826 | return false; | |
2263639f | 827 | if ((unsigned long)(bvec->bv_offset + skip) & addr_mask) |
cfa320f7 KB |
828 | return false; |
829 | ||
2263639f | 830 | bvec++; |
cfa320f7 | 831 | size -= len; |
2263639f JA |
832 | skip = 0; |
833 | } while (size); | |
834 | ||
cfa320f7 KB |
835 | return true; |
836 | } | |
837 | ||
838 | /** | |
839 | * iov_iter_is_aligned() - Check if the addresses and lengths of each segments | |
840 | * are aligned to the parameters. | |
841 | * | |
842 | * @i: &struct iov_iter to restore | |
843 | * @addr_mask: bit mask to check against the iov element's addresses | |
844 | * @len_mask: bit mask to check against the iov element's lengths | |
845 | * | |
846 | * Return: false if any addresses or lengths intersect with the provided masks | |
847 | */ | |
848 | bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, | |
849 | unsigned len_mask) | |
850 | { | |
fcb14cb1 AV |
851 | if (likely(iter_is_ubuf(i))) { |
852 | if (i->count & len_mask) | |
853 | return false; | |
854 | if ((unsigned long)(i->ubuf + i->iov_offset) & addr_mask) | |
855 | return false; | |
856 | return true; | |
857 | } | |
858 | ||
cfa320f7 KB |
859 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) |
860 | return iov_iter_aligned_iovec(i, addr_mask, len_mask); | |
861 | ||
862 | if (iov_iter_is_bvec(i)) | |
863 | return iov_iter_aligned_bvec(i, addr_mask, len_mask); | |
864 | ||
db0aa2e9 | 865 | /* With both xarray and folioq types, we're dealing with whole folios. */ |
cfa320f7 KB |
866 | if (iov_iter_is_xarray(i)) { |
867 | if (i->count & len_mask) | |
868 | return false; | |
869 | if ((i->xarray_start + i->iov_offset) & addr_mask) | |
870 | return false; | |
871 | } | |
db0aa2e9 DH |
872 | if (iov_iter_is_folioq(i)) { |
873 | if (i->count & len_mask) | |
874 | return false; | |
875 | if (i->iov_offset & addr_mask) | |
876 | return false; | |
877 | } | |
cfa320f7 KB |
878 | |
879 | return true; | |
880 | } | |
881 | EXPORT_SYMBOL_GPL(iov_iter_is_aligned); | |
882 | ||
9221d2e3 | 883 | static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) |
62a8067a | 884 | { |
2263639f | 885 | const struct iovec *iov = iter_iov(i); |
04a31165 AV |
886 | unsigned long res = 0; |
887 | size_t size = i->count; | |
9221d2e3 | 888 | size_t skip = i->iov_offset; |
9221d2e3 | 889 | |
2263639f | 890 | do { |
de4f5fed | 891 | size_t len = iov->iov_len - skip; |
9221d2e3 | 892 | if (len) { |
de4f5fed | 893 | res |= (unsigned long)iov->iov_base + skip; |
9221d2e3 AV |
894 | if (len > size) |
895 | len = size; | |
896 | res |= len; | |
897 | size -= len; | |
9221d2e3 | 898 | } |
2263639f JA |
899 | iov++; |
900 | skip = 0; | |
901 | } while (size); | |
9221d2e3 AV |
902 | return res; |
903 | } | |
04a31165 | 904 | |
9221d2e3 AV |
905 | static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) |
906 | { | |
2263639f | 907 | const struct bio_vec *bvec = i->bvec; |
9221d2e3 AV |
908 | unsigned res = 0; |
909 | size_t size = i->count; | |
910 | unsigned skip = i->iov_offset; | |
9221d2e3 | 911 | |
2263639f JA |
912 | do { |
913 | size_t len = bvec->bv_len - skip; | |
914 | res |= (unsigned long)bvec->bv_offset + skip; | |
9221d2e3 AV |
915 | if (len > size) |
916 | len = size; | |
917 | res |= len; | |
2263639f | 918 | bvec++; |
9221d2e3 | 919 | size -= len; |
2263639f JA |
920 | skip = 0; |
921 | } while (size); | |
922 | ||
9221d2e3 AV |
923 | return res; |
924 | } | |
925 | ||
926 | unsigned long iov_iter_alignment(const struct iov_iter *i) | |
927 | { | |
fcb14cb1 AV |
928 | if (likely(iter_is_ubuf(i))) { |
929 | size_t size = i->count; | |
930 | if (size) | |
931 | return ((unsigned long)i->ubuf + i->iov_offset) | size; | |
932 | return 0; | |
933 | } | |
934 | ||
9221d2e3 AV |
935 | /* iovec and kvec have identical layouts */ |
936 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
937 | return iov_iter_alignment_iovec(i); | |
938 | ||
939 | if (iov_iter_is_bvec(i)) | |
940 | return iov_iter_alignment_bvec(i); | |
941 | ||
db0aa2e9 DH |
942 | /* With both xarray and folioq types, we're dealing with whole folios. */ |
943 | if (iov_iter_is_folioq(i)) | |
944 | return i->iov_offset | i->count; | |
9221d2e3 | 945 | if (iov_iter_is_xarray(i)) |
3d14ec1f | 946 | return (i->xarray_start + i->iov_offset) | i->count; |
9221d2e3 AV |
947 | |
948 | return 0; | |
62a8067a AV |
949 | } |
950 | EXPORT_SYMBOL(iov_iter_alignment); | |
951 | ||
357f435d AV |
952 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
953 | { | |
33844e66 | 954 | unsigned long res = 0; |
610c7a71 | 955 | unsigned long v = 0; |
357f435d | 956 | size_t size = i->count; |
610c7a71 | 957 | unsigned k; |
357f435d | 958 | |
fcb14cb1 AV |
959 | if (iter_is_ubuf(i)) |
960 | return 0; | |
961 | ||
610c7a71 | 962 | if (WARN_ON(!iter_is_iovec(i))) |
241699cd | 963 | return ~0U; |
241699cd | 964 | |
610c7a71 | 965 | for (k = 0; k < i->nr_segs; k++) { |
de4f5fed JA |
966 | const struct iovec *iov = iter_iov(i) + k; |
967 | if (iov->iov_len) { | |
968 | unsigned long base = (unsigned long)iov->iov_base; | |
610c7a71 AV |
969 | if (v) // if not the first one |
970 | res |= base | v; // this start | previous end | |
de4f5fed JA |
971 | v = base + iov->iov_len; |
972 | if (size <= iov->iov_len) | |
610c7a71 | 973 | break; |
de4f5fed | 974 | size -= iov->iov_len; |
610c7a71 AV |
975 | } |
976 | } | |
33844e66 | 977 | return res; |
357f435d AV |
978 | } |
979 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
980 | ||
3cf42da3 AV |
981 | static int want_pages_array(struct page ***res, size_t size, |
982 | size_t start, unsigned int maxpages) | |
acbdeb83 | 983 | { |
3cf42da3 AV |
984 | unsigned int count = DIV_ROUND_UP(size + start, PAGE_SIZE); |
985 | ||
986 | if (count > maxpages) | |
987 | count = maxpages; | |
988 | WARN_ON(!count); // caller should've prevented that | |
989 | if (!*res) { | |
990 | *res = kvmalloc_array(count, sizeof(struct page *), GFP_KERNEL); | |
991 | if (!*res) | |
992 | return 0; | |
993 | } | |
994 | return count; | |
acbdeb83 AV |
995 | } |
996 | ||
db0aa2e9 DH |
997 | static ssize_t iter_folioq_get_pages(struct iov_iter *iter, |
998 | struct page ***ppages, size_t maxsize, | |
999 | unsigned maxpages, size_t *_start_offset) | |
1000 | { | |
1001 | const struct folio_queue *folioq = iter->folioq; | |
1002 | struct page **pages; | |
1003 | unsigned int slot = iter->folioq_slot; | |
1004 | size_t extracted = 0, count = iter->count, iov_offset = iter->iov_offset; | |
1005 | ||
1006 | if (slot >= folioq_nr_slots(folioq)) { | |
1007 | folioq = folioq->next; | |
1008 | slot = 0; | |
1009 | if (WARN_ON(iov_offset != 0)) | |
1010 | return -EIO; | |
1011 | } | |
1012 | ||
1013 | maxpages = want_pages_array(ppages, maxsize, iov_offset & ~PAGE_MASK, maxpages); | |
1014 | if (!maxpages) | |
1015 | return -ENOMEM; | |
1016 | *_start_offset = iov_offset & ~PAGE_MASK; | |
1017 | pages = *ppages; | |
1018 | ||
1019 | for (;;) { | |
1020 | struct folio *folio = folioq_folio(folioq, slot); | |
1021 | size_t offset = iov_offset, fsize = folioq_folio_size(folioq, slot); | |
1022 | size_t part = PAGE_SIZE - offset % PAGE_SIZE; | |
1023 | ||
1024 | part = umin(part, umin(maxsize - extracted, fsize - offset)); | |
1025 | count -= part; | |
1026 | iov_offset += part; | |
1027 | extracted += part; | |
1028 | ||
1029 | *pages = folio_page(folio, offset / PAGE_SIZE); | |
1030 | get_page(*pages); | |
1031 | pages++; | |
1032 | maxpages--; | |
1033 | if (maxpages == 0 || extracted >= maxsize) | |
1034 | break; | |
1035 | ||
1036 | if (offset >= fsize) { | |
1037 | iov_offset = 0; | |
1038 | slot++; | |
1039 | if (slot == folioq_nr_slots(folioq) && folioq->next) { | |
1040 | folioq = folioq->next; | |
1041 | slot = 0; | |
1042 | } | |
1043 | } | |
1044 | } | |
1045 | ||
1046 | iter->count = count; | |
1047 | iter->iov_offset = iov_offset; | |
1048 | iter->folioq = folioq; | |
1049 | iter->folioq_slot = slot; | |
1050 | return extracted; | |
1051 | } | |
1052 | ||
7ff50620 DH |
1053 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
1054 | pgoff_t index, unsigned int nr_pages) | |
1055 | { | |
1056 | XA_STATE(xas, xa, index); | |
1057 | struct page *page; | |
1058 | unsigned int ret = 0; | |
1059 | ||
1060 | rcu_read_lock(); | |
1061 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1062 | if (xas_retry(&xas, page)) | |
1063 | continue; | |
1064 | ||
1065 | /* Has the page moved or been split? */ | |
1066 | if (unlikely(page != xas_reload(&xas))) { | |
1067 | xas_reset(&xas); | |
1068 | continue; | |
1069 | } | |
1070 | ||
1071 | pages[ret] = find_subpage(page, xas.xa_index); | |
1072 | get_page(pages[ret]); | |
1073 | if (++ret == nr_pages) | |
1074 | break; | |
1075 | } | |
1076 | rcu_read_unlock(); | |
1077 | return ret; | |
1078 | } | |
1079 | ||
1080 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, | |
68fe506f | 1081 | struct page ***pages, size_t maxsize, |
7ff50620 DH |
1082 | unsigned maxpages, size_t *_start_offset) |
1083 | { | |
3cf42da3 AV |
1084 | unsigned nr, offset, count; |
1085 | pgoff_t index; | |
7ff50620 DH |
1086 | loff_t pos; |
1087 | ||
7ff50620 DH |
1088 | pos = i->xarray_start + i->iov_offset; |
1089 | index = pos >> PAGE_SHIFT; | |
1090 | offset = pos & ~PAGE_MASK; | |
1091 | *_start_offset = offset; | |
1092 | ||
3cf42da3 AV |
1093 | count = want_pages_array(pages, maxsize, offset, maxpages); |
1094 | if (!count) | |
1095 | return -ENOMEM; | |
68fe506f | 1096 | nr = iter_xarray_populate_pages(*pages, i->xarray, index, count); |
7ff50620 DH |
1097 | if (nr == 0) |
1098 | return 0; | |
1099 | ||
eba2d3d7 | 1100 | maxsize = min_t(size_t, nr * PAGE_SIZE - offset, maxsize); |
310d9d5a AV |
1101 | i->iov_offset += maxsize; |
1102 | i->count -= maxsize; | |
eba2d3d7 | 1103 | return maxsize; |
7ff50620 DH |
1104 | } |
1105 | ||
fcb14cb1 | 1106 | /* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ |
dd45ab9d | 1107 | static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size) |
3d671ca6 AV |
1108 | { |
1109 | size_t skip; | |
1110 | long k; | |
1111 | ||
fcb14cb1 AV |
1112 | if (iter_is_ubuf(i)) |
1113 | return (unsigned long)i->ubuf + i->iov_offset; | |
1114 | ||
3d671ca6 | 1115 | for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { |
de4f5fed JA |
1116 | const struct iovec *iov = iter_iov(i) + k; |
1117 | size_t len = iov->iov_len - skip; | |
3d671ca6 AV |
1118 | |
1119 | if (unlikely(!len)) | |
1120 | continue; | |
59dbd7d0 AV |
1121 | if (*size > len) |
1122 | *size = len; | |
de4f5fed | 1123 | return (unsigned long)iov->iov_base + skip; |
3d671ca6 AV |
1124 | } |
1125 | BUG(); // if it had been empty, we wouldn't get called | |
1126 | } | |
1127 | ||
1128 | /* must be done on non-empty ITER_BVEC one */ | |
1129 | static struct page *first_bvec_segment(const struct iov_iter *i, | |
59dbd7d0 | 1130 | size_t *size, size_t *start) |
3d671ca6 AV |
1131 | { |
1132 | struct page *page; | |
1133 | size_t skip = i->iov_offset, len; | |
1134 | ||
1135 | len = i->bvec->bv_len - skip; | |
59dbd7d0 AV |
1136 | if (*size > len) |
1137 | *size = len; | |
3d671ca6 AV |
1138 | skip += i->bvec->bv_offset; |
1139 | page = i->bvec->bv_page + skip / PAGE_SIZE; | |
dda8e5d1 | 1140 | *start = skip % PAGE_SIZE; |
3d671ca6 AV |
1141 | return page; |
1142 | } | |
1143 | ||
451c0ba9 AV |
1144 | static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, |
1145 | struct page ***pages, size_t maxsize, | |
84bd06c6 | 1146 | unsigned int maxpages, size_t *start) |
62a8067a | 1147 | { |
f62e52d1 | 1148 | unsigned int n, gup_flags = 0; |
3d671ca6 | 1149 | |
e5393fae AV |
1150 | if (maxsize > i->count) |
1151 | maxsize = i->count; | |
451c0ba9 | 1152 | if (!maxsize) |
3d671ca6 | 1153 | return 0; |
7392ed17 AV |
1154 | if (maxsize > MAX_RW_COUNT) |
1155 | maxsize = MAX_RW_COUNT; | |
e5393fae | 1156 | |
fcb14cb1 | 1157 | if (likely(user_backed_iter(i))) { |
3d671ca6 | 1158 | unsigned long addr; |
3cf42da3 | 1159 | int res; |
e5393fae | 1160 | |
3337ab08 AG |
1161 | if (iov_iter_rw(i) != WRITE) |
1162 | gup_flags |= FOLL_WRITE; | |
1163 | if (i->nofault) | |
1164 | gup_flags |= FOLL_NOFAULT; | |
1165 | ||
dd45ab9d AV |
1166 | addr = first_iovec_segment(i, &maxsize); |
1167 | *start = addr % PAGE_SIZE; | |
1168 | addr &= PAGE_MASK; | |
3cf42da3 AV |
1169 | n = want_pages_array(pages, maxsize, *start, maxpages); |
1170 | if (!n) | |
1171 | return -ENOMEM; | |
451c0ba9 | 1172 | res = get_user_pages_fast(addr, n, gup_flags, *pages); |
814a6674 | 1173 | if (unlikely(res <= 0)) |
e5393fae | 1174 | return res; |
eba2d3d7 AV |
1175 | maxsize = min_t(size_t, maxsize, res * PAGE_SIZE - *start); |
1176 | iov_iter_advance(i, maxsize); | |
1177 | return maxsize; | |
3d671ca6 AV |
1178 | } |
1179 | if (iov_iter_is_bvec(i)) { | |
451c0ba9 | 1180 | struct page **p; |
3d671ca6 AV |
1181 | struct page *page; |
1182 | ||
59dbd7d0 | 1183 | page = first_bvec_segment(i, &maxsize, start); |
3cf42da3 AV |
1184 | n = want_pages_array(pages, maxsize, *start, maxpages); |
1185 | if (!n) | |
1186 | return -ENOMEM; | |
451c0ba9 | 1187 | p = *pages; |
dda8e5d1 | 1188 | for (int k = 0; k < n; k++) |
eba2d3d7 AV |
1189 | get_page(p[k] = page + k); |
1190 | maxsize = min_t(size_t, maxsize, n * PAGE_SIZE - *start); | |
310d9d5a AV |
1191 | i->count -= maxsize; |
1192 | i->iov_offset += maxsize; | |
1193 | if (i->iov_offset == i->bvec->bv_len) { | |
1194 | i->iov_offset = 0; | |
1195 | i->bvec++; | |
1196 | i->nr_segs--; | |
1197 | } | |
eba2d3d7 | 1198 | return maxsize; |
3d671ca6 | 1199 | } |
db0aa2e9 DH |
1200 | if (iov_iter_is_folioq(i)) |
1201 | return iter_folioq_get_pages(i, pages, maxsize, maxpages, start); | |
3d671ca6 | 1202 | if (iov_iter_is_xarray(i)) |
451c0ba9 | 1203 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); |
3d671ca6 | 1204 | return -EFAULT; |
62a8067a | 1205 | } |
62a8067a | 1206 | |
84bd06c6 CH |
1207 | ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages, |
1208 | size_t maxsize, unsigned maxpages, size_t *start) | |
62a8067a | 1209 | { |
451c0ba9 | 1210 | if (!maxpages) |
3d671ca6 | 1211 | return 0; |
451c0ba9 | 1212 | BUG_ON(!pages); |
3d671ca6 | 1213 | |
84bd06c6 | 1214 | return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start); |
62a8067a | 1215 | } |
eba2d3d7 | 1216 | EXPORT_SYMBOL(iov_iter_get_pages2); |
91329559 | 1217 | |
84bd06c6 CH |
1218 | ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, |
1219 | struct page ***pages, size_t maxsize, size_t *start) | |
91329559 AV |
1220 | { |
1221 | ssize_t len; | |
1222 | ||
1223 | *pages = NULL; | |
1224 | ||
84bd06c6 | 1225 | len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start); |
91329559 AV |
1226 | if (len <= 0) { |
1227 | kvfree(*pages); | |
1228 | *pages = NULL; | |
1229 | } | |
1230 | return len; | |
1231 | } | |
eba2d3d7 | 1232 | EXPORT_SYMBOL(iov_iter_get_pages_alloc2); |
62a8067a | 1233 | |
66531c65 | 1234 | static int iov_npages(const struct iov_iter *i, int maxpages) |
62a8067a | 1235 | { |
66531c65 AV |
1236 | size_t skip = i->iov_offset, size = i->count; |
1237 | const struct iovec *p; | |
e0f2dc40 AV |
1238 | int npages = 0; |
1239 | ||
de4f5fed | 1240 | for (p = iter_iov(i); size; skip = 0, p++) { |
66531c65 AV |
1241 | unsigned offs = offset_in_page(p->iov_base + skip); |
1242 | size_t len = min(p->iov_len - skip, size); | |
e0f2dc40 | 1243 | |
66531c65 AV |
1244 | if (len) { |
1245 | size -= len; | |
1246 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1247 | if (unlikely(npages > maxpages)) | |
1248 | return maxpages; | |
1249 | } | |
1250 | } | |
1251 | return npages; | |
1252 | } | |
1253 | ||
1254 | static int bvec_npages(const struct iov_iter *i, int maxpages) | |
1255 | { | |
1256 | size_t skip = i->iov_offset, size = i->count; | |
1257 | const struct bio_vec *p; | |
1258 | int npages = 0; | |
1259 | ||
1260 | for (p = i->bvec; size; skip = 0, p++) { | |
1261 | unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; | |
1262 | size_t len = min(p->bv_len - skip, size); | |
1263 | ||
1264 | size -= len; | |
1265 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1266 | if (unlikely(npages > maxpages)) | |
1267 | return maxpages; | |
1268 | } | |
1269 | return npages; | |
1270 | } | |
1271 | ||
1272 | int iov_iter_npages(const struct iov_iter *i, int maxpages) | |
1273 | { | |
1274 | if (unlikely(!i->count)) | |
1275 | return 0; | |
fcb14cb1 AV |
1276 | if (likely(iter_is_ubuf(i))) { |
1277 | unsigned offs = offset_in_page(i->ubuf + i->iov_offset); | |
1278 | int npages = DIV_ROUND_UP(offs + i->count, PAGE_SIZE); | |
1279 | return min(npages, maxpages); | |
1280 | } | |
66531c65 AV |
1281 | /* iovec and kvec have identical layouts */ |
1282 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1283 | return iov_npages(i, maxpages); | |
1284 | if (iov_iter_is_bvec(i)) | |
1285 | return bvec_npages(i, maxpages); | |
db0aa2e9 DH |
1286 | if (iov_iter_is_folioq(i)) { |
1287 | unsigned offset = i->iov_offset % PAGE_SIZE; | |
1288 | int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); | |
1289 | return min(npages, maxpages); | |
1290 | } | |
66531c65 | 1291 | if (iov_iter_is_xarray(i)) { |
e4f8df86 AV |
1292 | unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; |
1293 | int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); | |
66531c65 AV |
1294 | return min(npages, maxpages); |
1295 | } | |
1296 | return 0; | |
62a8067a | 1297 | } |
f67da30c | 1298 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1299 | |
1300 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1301 | { | |
1302 | *new = *old; | |
00e23707 | 1303 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1304 | return new->bvec = kmemdup(new->bvec, |
1305 | new->nr_segs * sizeof(struct bio_vec), | |
1306 | flags); | |
fcb14cb1 | 1307 | else if (iov_iter_is_kvec(new) || iter_is_iovec(new)) |
4b8164b9 | 1308 | /* iovec and kvec have identical layout */ |
de4f5fed | 1309 | return new->__iov = kmemdup(new->__iov, |
4b8164b9 AV |
1310 | new->nr_segs * sizeof(struct iovec), |
1311 | flags); | |
fcb14cb1 | 1312 | return NULL; |
4b8164b9 AV |
1313 | } |
1314 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1315 | |
50f9a76e | 1316 | static __noclone int copy_compat_iovec_from_user(struct iovec *iov, |
bd8c239c | 1317 | const struct iovec __user *uvec, u32 nr_segs) |
bfdc5970 CH |
1318 | { |
1319 | const struct compat_iovec __user *uiov = | |
1320 | (const struct compat_iovec __user *)uvec; | |
bd8c239c KC |
1321 | int ret = -EFAULT; |
1322 | u32 i; | |
bfdc5970 | 1323 | |
a959a978 | 1324 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
1325 | return -EFAULT; |
1326 | ||
1327 | for (i = 0; i < nr_segs; i++) { | |
1328 | compat_uptr_t buf; | |
1329 | compat_ssize_t len; | |
1330 | ||
1331 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); | |
1332 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); | |
1333 | ||
1334 | /* check for compat_size_t not fitting in compat_ssize_t .. */ | |
1335 | if (len < 0) { | |
1336 | ret = -EINVAL; | |
1337 | goto uaccess_end; | |
1338 | } | |
1339 | iov[i].iov_base = compat_ptr(buf); | |
1340 | iov[i].iov_len = len; | |
1341 | } | |
1342 | ||
1343 | ret = 0; | |
1344 | uaccess_end: | |
1345 | user_access_end(); | |
1346 | return ret; | |
1347 | } | |
1348 | ||
719a937b | 1349 | static __noclone int copy_iovec_from_user(struct iovec *iov, |
487c20b0 | 1350 | const struct iovec __user *uiov, unsigned long nr_segs) |
fb041b59 | 1351 | { |
487c20b0 | 1352 | int ret = -EFAULT; |
fb041b59 | 1353 | |
487c20b0 | 1354 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 | 1355 | return -EFAULT; |
fb041b59 | 1356 | |
487c20b0 LT |
1357 | do { |
1358 | void __user *buf; | |
1359 | ssize_t len; | |
1360 | ||
1361 | unsafe_get_user(len, &uiov->iov_len, uaccess_end); | |
1362 | unsafe_get_user(buf, &uiov->iov_base, uaccess_end); | |
1363 | ||
1364 | /* check for size_t not fitting in ssize_t .. */ | |
1365 | if (unlikely(len < 0)) { | |
1366 | ret = -EINVAL; | |
1367 | goto uaccess_end; | |
1368 | } | |
1369 | iov->iov_base = buf; | |
1370 | iov->iov_len = len; | |
1371 | ||
1372 | uiov++; iov++; | |
1373 | } while (--nr_segs); | |
1374 | ||
1375 | ret = 0; | |
1376 | uaccess_end: | |
1377 | user_access_end(); | |
1378 | return ret; | |
bfdc5970 CH |
1379 | } |
1380 | ||
1381 | struct iovec *iovec_from_user(const struct iovec __user *uvec, | |
1382 | unsigned long nr_segs, unsigned long fast_segs, | |
1383 | struct iovec *fast_iov, bool compat) | |
1384 | { | |
1385 | struct iovec *iov = fast_iov; | |
1386 | int ret; | |
1387 | ||
fb041b59 | 1388 | /* |
bfdc5970 CH |
1389 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
1390 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
1391 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 1392 | */ |
bfdc5970 CH |
1393 | if (nr_segs == 0) |
1394 | return iov; | |
1395 | if (nr_segs > UIO_MAXIOV) | |
1396 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
1397 | if (nr_segs > fast_segs) { |
1398 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
1399 | if (!iov) |
1400 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 1401 | } |
bfdc5970 | 1402 | |
487c20b0 | 1403 | if (unlikely(compat)) |
bfdc5970 CH |
1404 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); |
1405 | else | |
1406 | ret = copy_iovec_from_user(iov, uvec, nr_segs); | |
1407 | if (ret) { | |
1408 | if (iov != fast_iov) | |
1409 | kfree(iov); | |
1410 | return ERR_PTR(ret); | |
1411 | } | |
1412 | ||
1413 | return iov; | |
1414 | } | |
1415 | ||
3b2deb0e JA |
1416 | /* |
1417 | * Single segment iovec supplied by the user, import it as ITER_UBUF. | |
1418 | */ | |
1419 | static ssize_t __import_iovec_ubuf(int type, const struct iovec __user *uvec, | |
1420 | struct iovec **iovp, struct iov_iter *i, | |
1421 | bool compat) | |
1422 | { | |
1423 | struct iovec *iov = *iovp; | |
1424 | ssize_t ret; | |
1425 | ||
1426 | if (compat) | |
1427 | ret = copy_compat_iovec_from_user(iov, uvec, 1); | |
1428 | else | |
1429 | ret = copy_iovec_from_user(iov, uvec, 1); | |
1430 | if (unlikely(ret)) | |
1431 | return ret; | |
1432 | ||
1433 | ret = import_ubuf(type, iov->iov_base, iov->iov_len, i); | |
1434 | if (unlikely(ret)) | |
1435 | return ret; | |
1436 | *iovp = NULL; | |
1437 | return i->count; | |
1438 | } | |
1439 | ||
bfdc5970 CH |
1440 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, |
1441 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
1442 | struct iov_iter *i, bool compat) | |
1443 | { | |
1444 | ssize_t total_len = 0; | |
1445 | unsigned long seg; | |
1446 | struct iovec *iov; | |
1447 | ||
3b2deb0e JA |
1448 | if (nr_segs == 1) |
1449 | return __import_iovec_ubuf(type, uvec, iovp, i, compat); | |
1450 | ||
bfdc5970 CH |
1451 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); |
1452 | if (IS_ERR(iov)) { | |
1453 | *iovp = NULL; | |
1454 | return PTR_ERR(iov); | |
fb041b59 DL |
1455 | } |
1456 | ||
1457 | /* | |
bfdc5970 CH |
1458 | * According to the Single Unix Specification we should return EINVAL if |
1459 | * an element length is < 0 when cast to ssize_t or if the total length | |
1460 | * would overflow the ssize_t return value of the system call. | |
fb041b59 DL |
1461 | * |
1462 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
1463 | * overflow case. | |
1464 | */ | |
fb041b59 | 1465 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
1466 | ssize_t len = (ssize_t)iov[seg].iov_len; |
1467 | ||
bfdc5970 CH |
1468 | if (!access_ok(iov[seg].iov_base, len)) { |
1469 | if (iov != *iovp) | |
1470 | kfree(iov); | |
1471 | *iovp = NULL; | |
1472 | return -EFAULT; | |
fb041b59 | 1473 | } |
bfdc5970 CH |
1474 | |
1475 | if (len > MAX_RW_COUNT - total_len) { | |
1476 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
1477 | iov[seg].iov_len = len; |
1478 | } | |
bfdc5970 | 1479 | total_len += len; |
fb041b59 | 1480 | } |
bfdc5970 CH |
1481 | |
1482 | iov_iter_init(i, type, iov, nr_segs, total_len); | |
1483 | if (iov == *iovp) | |
1484 | *iovp = NULL; | |
1485 | else | |
1486 | *iovp = iov; | |
1487 | return total_len; | |
fb041b59 DL |
1488 | } |
1489 | ||
ffecee4f VN |
1490 | /** |
1491 | * import_iovec() - Copy an array of &struct iovec from userspace | |
1492 | * into the kernel, check that it is valid, and initialize a new | |
1493 | * &struct iov_iter iterator to access it. | |
1494 | * | |
1495 | * @type: One of %READ or %WRITE. | |
bfdc5970 | 1496 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
1497 | * @nr_segs: Number of elements in userspace array. |
1498 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 1499 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
1500 | * on-stack) kernel array. |
1501 | * @i: Pointer to iterator that will be initialized on success. | |
1502 | * | |
1503 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
1504 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
1505 | * array will be allocated and the result placed in *@iov. This means that | |
1506 | * the caller may call kfree() on *@iov regardless of whether the small | |
1507 | * on-stack array was used or not (and regardless of whether this function | |
1508 | * returns an error or not). | |
1509 | * | |
87e5e6da | 1510 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 1511 | */ |
bfdc5970 | 1512 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 1513 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 1514 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 1515 | { |
89cd35c5 CH |
1516 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
1517 | in_compat_syscall()); | |
bc917be8 AV |
1518 | } |
1519 | EXPORT_SYMBOL(import_iovec); | |
1520 | ||
2ad9bd83 JA |
1521 | int import_ubuf(int rw, void __user *buf, size_t len, struct iov_iter *i) |
1522 | { | |
1523 | if (len > MAX_RW_COUNT) | |
1524 | len = MAX_RW_COUNT; | |
1525 | if (unlikely(!access_ok(buf, len))) | |
1526 | return -EFAULT; | |
1527 | ||
1528 | iov_iter_ubuf(i, rw, buf, len); | |
1529 | return 0; | |
1530 | } | |
70e969eb | 1531 | EXPORT_SYMBOL_GPL(import_ubuf); |
2ad9bd83 | 1532 | |
8fb0f47a JA |
1533 | /** |
1534 | * iov_iter_restore() - Restore a &struct iov_iter to the same state as when | |
1535 | * iov_iter_save_state() was called. | |
1536 | * | |
1537 | * @i: &struct iov_iter to restore | |
1538 | * @state: state to restore from | |
1539 | * | |
1540 | * Used after iov_iter_save_state() to bring restore @i, if operations may | |
1541 | * have advanced it. | |
1542 | * | |
1543 | * Note: only works on ITER_IOVEC, ITER_BVEC, and ITER_KVEC | |
1544 | */ | |
1545 | void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) | |
1546 | { | |
4397a17c KB |
1547 | if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i) && |
1548 | !iter_is_ubuf(i)) && !iov_iter_is_kvec(i)) | |
8fb0f47a JA |
1549 | return; |
1550 | i->iov_offset = state->iov_offset; | |
1551 | i->count = state->count; | |
fcb14cb1 AV |
1552 | if (iter_is_ubuf(i)) |
1553 | return; | |
8fb0f47a JA |
1554 | /* |
1555 | * For the *vec iters, nr_segs + iov is constant - if we increment | |
1556 | * the vec, then we also decrement the nr_segs count. Hence we don't | |
1557 | * need to track both of these, just one is enough and we can deduct | |
1558 | * the other from that. ITER_KVEC and ITER_IOVEC are the same struct | |
1559 | * size, so we can just increment the iov pointer as they are unionzed. | |
1560 | * ITER_BVEC _may_ be the same size on some archs, but on others it is | |
1561 | * not. Be safe and handle it separately. | |
1562 | */ | |
1563 | BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); | |
1564 | if (iov_iter_is_bvec(i)) | |
1565 | i->bvec -= state->nr_segs - i->nr_segs; | |
1566 | else | |
de4f5fed | 1567 | i->__iov -= state->nr_segs - i->nr_segs; |
8fb0f47a JA |
1568 | i->nr_segs = state->nr_segs; |
1569 | } | |
7d58fe73 | 1570 | |
db0aa2e9 DH |
1571 | /* |
1572 | * Extract a list of contiguous pages from an ITER_FOLIOQ iterator. This does | |
1573 | * not get references on the pages, nor does it get a pin on them. | |
1574 | */ | |
1575 | static ssize_t iov_iter_extract_folioq_pages(struct iov_iter *i, | |
1576 | struct page ***pages, size_t maxsize, | |
1577 | unsigned int maxpages, | |
1578 | iov_iter_extraction_t extraction_flags, | |
1579 | size_t *offset0) | |
1580 | { | |
1581 | const struct folio_queue *folioq = i->folioq; | |
1582 | struct page **p; | |
1583 | unsigned int nr = 0; | |
1584 | size_t extracted = 0, offset, slot = i->folioq_slot; | |
1585 | ||
1586 | if (slot >= folioq_nr_slots(folioq)) { | |
1587 | folioq = folioq->next; | |
1588 | slot = 0; | |
1589 | if (WARN_ON(i->iov_offset != 0)) | |
1590 | return -EIO; | |
1591 | } | |
1592 | ||
1593 | offset = i->iov_offset & ~PAGE_MASK; | |
1594 | *offset0 = offset; | |
1595 | ||
1596 | maxpages = want_pages_array(pages, maxsize, offset, maxpages); | |
1597 | if (!maxpages) | |
1598 | return -ENOMEM; | |
1599 | p = *pages; | |
1600 | ||
1601 | for (;;) { | |
1602 | struct folio *folio = folioq_folio(folioq, slot); | |
1603 | size_t offset = i->iov_offset, fsize = folioq_folio_size(folioq, slot); | |
1604 | size_t part = PAGE_SIZE - offset % PAGE_SIZE; | |
1605 | ||
1606 | if (offset < fsize) { | |
1607 | part = umin(part, umin(maxsize - extracted, fsize - offset)); | |
1608 | i->count -= part; | |
1609 | i->iov_offset += part; | |
1610 | extracted += part; | |
1611 | ||
1612 | p[nr++] = folio_page(folio, offset / PAGE_SIZE); | |
1613 | } | |
1614 | ||
1615 | if (nr >= maxpages || extracted >= maxsize) | |
1616 | break; | |
1617 | ||
1618 | if (i->iov_offset >= fsize) { | |
1619 | i->iov_offset = 0; | |
1620 | slot++; | |
1621 | if (slot == folioq_nr_slots(folioq) && folioq->next) { | |
1622 | folioq = folioq->next; | |
1623 | slot = 0; | |
1624 | } | |
1625 | } | |
1626 | } | |
1627 | ||
1628 | i->folioq = folioq; | |
1629 | i->folioq_slot = slot; | |
1630 | return extracted; | |
1631 | } | |
1632 | ||
7d58fe73 DH |
1633 | /* |
1634 | * Extract a list of contiguous pages from an ITER_XARRAY iterator. This does not | |
1635 | * get references on the pages, nor does it get a pin on them. | |
1636 | */ | |
1637 | static ssize_t iov_iter_extract_xarray_pages(struct iov_iter *i, | |
1638 | struct page ***pages, size_t maxsize, | |
1639 | unsigned int maxpages, | |
1640 | iov_iter_extraction_t extraction_flags, | |
1641 | size_t *offset0) | |
1642 | { | |
1643 | struct page *page, **p; | |
1644 | unsigned int nr = 0, offset; | |
1645 | loff_t pos = i->xarray_start + i->iov_offset; | |
1646 | pgoff_t index = pos >> PAGE_SHIFT; | |
1647 | XA_STATE(xas, i->xarray, index); | |
1648 | ||
1649 | offset = pos & ~PAGE_MASK; | |
1650 | *offset0 = offset; | |
1651 | ||
1652 | maxpages = want_pages_array(pages, maxsize, offset, maxpages); | |
1653 | if (!maxpages) | |
1654 | return -ENOMEM; | |
1655 | p = *pages; | |
1656 | ||
1657 | rcu_read_lock(); | |
1658 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1659 | if (xas_retry(&xas, page)) | |
1660 | continue; | |
1661 | ||
1662 | /* Has the page moved or been split? */ | |
1663 | if (unlikely(page != xas_reload(&xas))) { | |
1664 | xas_reset(&xas); | |
1665 | continue; | |
1666 | } | |
1667 | ||
1668 | p[nr++] = find_subpage(page, xas.xa_index); | |
1669 | if (nr == maxpages) | |
1670 | break; | |
1671 | } | |
1672 | rcu_read_unlock(); | |
1673 | ||
1674 | maxsize = min_t(size_t, nr * PAGE_SIZE - offset, maxsize); | |
1675 | iov_iter_advance(i, maxsize); | |
1676 | return maxsize; | |
1677 | } | |
1678 | ||
1679 | /* | |
1680 | * Extract a list of contiguous pages from an ITER_BVEC iterator. This does | |
1681 | * not get references on the pages, nor does it get a pin on them. | |
1682 | */ | |
1683 | static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i, | |
1684 | struct page ***pages, size_t maxsize, | |
1685 | unsigned int maxpages, | |
1686 | iov_iter_extraction_t extraction_flags, | |
1687 | size_t *offset0) | |
1688 | { | |
1689 | struct page **p, *page; | |
f741bd71 | 1690 | size_t skip = i->iov_offset, offset, size; |
7d58fe73 DH |
1691 | int k; |
1692 | ||
1693 | for (;;) { | |
1694 | if (i->nr_segs == 0) | |
1695 | return 0; | |
f741bd71 DH |
1696 | size = min(maxsize, i->bvec->bv_len - skip); |
1697 | if (size) | |
7d58fe73 DH |
1698 | break; |
1699 | i->iov_offset = 0; | |
1700 | i->nr_segs--; | |
1701 | i->bvec++; | |
1702 | skip = 0; | |
1703 | } | |
1704 | ||
1705 | skip += i->bvec->bv_offset; | |
1706 | page = i->bvec->bv_page + skip / PAGE_SIZE; | |
1707 | offset = skip % PAGE_SIZE; | |
1708 | *offset0 = offset; | |
1709 | ||
f741bd71 | 1710 | maxpages = want_pages_array(pages, size, offset, maxpages); |
7d58fe73 DH |
1711 | if (!maxpages) |
1712 | return -ENOMEM; | |
1713 | p = *pages; | |
1714 | for (k = 0; k < maxpages; k++) | |
1715 | p[k] = page + k; | |
1716 | ||
f741bd71 DH |
1717 | size = min_t(size_t, size, maxpages * PAGE_SIZE - offset); |
1718 | iov_iter_advance(i, size); | |
1719 | return size; | |
7d58fe73 DH |
1720 | } |
1721 | ||
1722 | /* | |
1723 | * Extract a list of virtually contiguous pages from an ITER_KVEC iterator. | |
1724 | * This does not get references on the pages, nor does it get a pin on them. | |
1725 | */ | |
1726 | static ssize_t iov_iter_extract_kvec_pages(struct iov_iter *i, | |
1727 | struct page ***pages, size_t maxsize, | |
1728 | unsigned int maxpages, | |
1729 | iov_iter_extraction_t extraction_flags, | |
1730 | size_t *offset0) | |
1731 | { | |
1732 | struct page **p, *page; | |
1733 | const void *kaddr; | |
f741bd71 | 1734 | size_t skip = i->iov_offset, offset, len, size; |
7d58fe73 DH |
1735 | int k; |
1736 | ||
1737 | for (;;) { | |
1738 | if (i->nr_segs == 0) | |
1739 | return 0; | |
f741bd71 DH |
1740 | size = min(maxsize, i->kvec->iov_len - skip); |
1741 | if (size) | |
7d58fe73 DH |
1742 | break; |
1743 | i->iov_offset = 0; | |
1744 | i->nr_segs--; | |
1745 | i->kvec++; | |
1746 | skip = 0; | |
1747 | } | |
1748 | ||
1749 | kaddr = i->kvec->iov_base + skip; | |
1750 | offset = (unsigned long)kaddr & ~PAGE_MASK; | |
1751 | *offset0 = offset; | |
1752 | ||
f741bd71 | 1753 | maxpages = want_pages_array(pages, size, offset, maxpages); |
7d58fe73 DH |
1754 | if (!maxpages) |
1755 | return -ENOMEM; | |
1756 | p = *pages; | |
1757 | ||
1758 | kaddr -= offset; | |
f741bd71 | 1759 | len = offset + size; |
7d58fe73 DH |
1760 | for (k = 0; k < maxpages; k++) { |
1761 | size_t seg = min_t(size_t, len, PAGE_SIZE); | |
1762 | ||
1763 | if (is_vmalloc_or_module_addr(kaddr)) | |
1764 | page = vmalloc_to_page(kaddr); | |
1765 | else | |
1766 | page = virt_to_page(kaddr); | |
1767 | ||
1768 | p[k] = page; | |
1769 | len -= seg; | |
1770 | kaddr += PAGE_SIZE; | |
1771 | } | |
1772 | ||
f741bd71 DH |
1773 | size = min_t(size_t, size, maxpages * PAGE_SIZE - offset); |
1774 | iov_iter_advance(i, size); | |
1775 | return size; | |
7d58fe73 DH |
1776 | } |
1777 | ||
1778 | /* | |
1779 | * Extract a list of contiguous pages from a user iterator and get a pin on | |
1780 | * each of them. This should only be used if the iterator is user-backed | |
1781 | * (IOBUF/UBUF). | |
1782 | * | |
1783 | * It does not get refs on the pages, but the pages must be unpinned by the | |
1784 | * caller once the transfer is complete. | |
1785 | * | |
1786 | * This is safe to be used where background IO/DMA *is* going to be modifying | |
1787 | * the buffer; using a pin rather than a ref makes forces fork() to give the | |
1788 | * child a copy of the page. | |
1789 | */ | |
1790 | static ssize_t iov_iter_extract_user_pages(struct iov_iter *i, | |
1791 | struct page ***pages, | |
1792 | size_t maxsize, | |
1793 | unsigned int maxpages, | |
1794 | iov_iter_extraction_t extraction_flags, | |
1795 | size_t *offset0) | |
1796 | { | |
1797 | unsigned long addr; | |
1798 | unsigned int gup_flags = 0; | |
1799 | size_t offset; | |
1800 | int res; | |
1801 | ||
1802 | if (i->data_source == ITER_DEST) | |
1803 | gup_flags |= FOLL_WRITE; | |
1804 | if (extraction_flags & ITER_ALLOW_P2PDMA) | |
1805 | gup_flags |= FOLL_PCI_P2PDMA; | |
1806 | if (i->nofault) | |
1807 | gup_flags |= FOLL_NOFAULT; | |
1808 | ||
1809 | addr = first_iovec_segment(i, &maxsize); | |
1810 | *offset0 = offset = addr % PAGE_SIZE; | |
1811 | addr &= PAGE_MASK; | |
1812 | maxpages = want_pages_array(pages, maxsize, offset, maxpages); | |
1813 | if (!maxpages) | |
1814 | return -ENOMEM; | |
1815 | res = pin_user_pages_fast(addr, maxpages, gup_flags, *pages); | |
1816 | if (unlikely(res <= 0)) | |
1817 | return res; | |
1818 | maxsize = min_t(size_t, maxsize, res * PAGE_SIZE - offset); | |
1819 | iov_iter_advance(i, maxsize); | |
1820 | return maxsize; | |
1821 | } | |
1822 | ||
1823 | /** | |
1824 | * iov_iter_extract_pages - Extract a list of contiguous pages from an iterator | |
1825 | * @i: The iterator to extract from | |
1826 | * @pages: Where to return the list of pages | |
1827 | * @maxsize: The maximum amount of iterator to extract | |
1828 | * @maxpages: The maximum size of the list of pages | |
1829 | * @extraction_flags: Flags to qualify request | |
1830 | * @offset0: Where to return the starting offset into (*@pages)[0] | |
1831 | * | |
1832 | * Extract a list of contiguous pages from the current point of the iterator, | |
1833 | * advancing the iterator. The maximum number of pages and the maximum amount | |
1834 | * of page contents can be set. | |
1835 | * | |
1836 | * If *@pages is NULL, a page list will be allocated to the required size and | |
1837 | * *@pages will be set to its base. If *@pages is not NULL, it will be assumed | |
1838 | * that the caller allocated a page list at least @maxpages in size and this | |
1839 | * will be filled in. | |
1840 | * | |
1841 | * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA | |
1842 | * be allowed on the pages extracted. | |
1843 | * | |
1844 | * The iov_iter_extract_will_pin() function can be used to query how cleanup | |
1845 | * should be performed. | |
1846 | * | |
1847 | * Extra refs or pins on the pages may be obtained as follows: | |
1848 | * | |
1849 | * (*) If the iterator is user-backed (ITER_IOVEC/ITER_UBUF), pins will be | |
1850 | * added to the pages, but refs will not be taken. | |
1851 | * iov_iter_extract_will_pin() will return true. | |
1852 | * | |
db0aa2e9 DH |
1853 | * (*) If the iterator is ITER_KVEC, ITER_BVEC, ITER_FOLIOQ or ITER_XARRAY, the |
1854 | * pages are merely listed; no extra refs or pins are obtained. | |
7d58fe73 DH |
1855 | * iov_iter_extract_will_pin() will return 0. |
1856 | * | |
1857 | * Note also: | |
1858 | * | |
1859 | * (*) Use with ITER_DISCARD is not supported as that has no content. | |
1860 | * | |
1861 | * On success, the function sets *@pages to the new pagelist, if allocated, and | |
1862 | * sets *offset0 to the offset into the first page. | |
1863 | * | |
1864 | * It may also return -ENOMEM and -EFAULT. | |
1865 | */ | |
1866 | ssize_t iov_iter_extract_pages(struct iov_iter *i, | |
1867 | struct page ***pages, | |
1868 | size_t maxsize, | |
1869 | unsigned int maxpages, | |
1870 | iov_iter_extraction_t extraction_flags, | |
1871 | size_t *offset0) | |
1872 | { | |
1873 | maxsize = min_t(size_t, min_t(size_t, maxsize, i->count), MAX_RW_COUNT); | |
1874 | if (!maxsize) | |
1875 | return 0; | |
1876 | ||
1877 | if (likely(user_backed_iter(i))) | |
1878 | return iov_iter_extract_user_pages(i, pages, maxsize, | |
1879 | maxpages, extraction_flags, | |
1880 | offset0); | |
1881 | if (iov_iter_is_kvec(i)) | |
1882 | return iov_iter_extract_kvec_pages(i, pages, maxsize, | |
1883 | maxpages, extraction_flags, | |
1884 | offset0); | |
1885 | if (iov_iter_is_bvec(i)) | |
1886 | return iov_iter_extract_bvec_pages(i, pages, maxsize, | |
1887 | maxpages, extraction_flags, | |
1888 | offset0); | |
db0aa2e9 DH |
1889 | if (iov_iter_is_folioq(i)) |
1890 | return iov_iter_extract_folioq_pages(i, pages, maxsize, | |
1891 | maxpages, extraction_flags, | |
1892 | offset0); | |
7d58fe73 DH |
1893 | if (iov_iter_is_xarray(i)) |
1894 | return iov_iter_extract_xarray_pages(i, pages, maxsize, | |
1895 | maxpages, extraction_flags, | |
1896 | offset0); | |
1897 | return -EFAULT; | |
1898 | } | |
1899 | EXPORT_SYMBOL_GPL(iov_iter_extract_pages); |