Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
7999096f | 2 | #include <crypto/hash.h> |
4f18cd31 | 3 | #include <linux/export.h> |
2f8b5444 | 4 | #include <linux/bvec.h> |
4d0e9df5 | 5 | #include <linux/fault-inject-usercopy.h> |
4f18cd31 AV |
6 | #include <linux/uio.h> |
7 | #include <linux/pagemap.h> | |
28961998 | 8 | #include <linux/highmem.h> |
91f79c43 AV |
9 | #include <linux/slab.h> |
10 | #include <linux/vmalloc.h> | |
241699cd | 11 | #include <linux/splice.h> |
bfdc5970 | 12 | #include <linux/compat.h> |
a604ec7e | 13 | #include <net/checksum.h> |
d05f4435 | 14 | #include <linux/scatterlist.h> |
d0ef4c36 | 15 | #include <linux/instrumented.h> |
4f18cd31 | 16 | |
241699cd AV |
17 | #define PIPE_PARANOIA /* for now */ |
18 | ||
04a31165 AV |
19 | #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ |
20 | size_t left; \ | |
21 | size_t wanted = n; \ | |
22 | __p = i->iov; \ | |
23 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
24 | if (likely(__v.iov_len)) { \ | |
25 | __v.iov_base = __p->iov_base + skip; \ | |
26 | left = (STEP); \ | |
27 | __v.iov_len -= left; \ | |
28 | skip += __v.iov_len; \ | |
29 | n -= __v.iov_len; \ | |
30 | } else { \ | |
31 | left = 0; \ | |
32 | } \ | |
33 | while (unlikely(!left && n)) { \ | |
34 | __p++; \ | |
35 | __v.iov_len = min(n, __p->iov_len); \ | |
36 | if (unlikely(!__v.iov_len)) \ | |
37 | continue; \ | |
38 | __v.iov_base = __p->iov_base; \ | |
39 | left = (STEP); \ | |
40 | __v.iov_len -= left; \ | |
41 | skip = __v.iov_len; \ | |
42 | n -= __v.iov_len; \ | |
43 | } \ | |
44 | n = wanted - n; \ | |
45 | } | |
46 | ||
a280455f AV |
47 | #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ |
48 | size_t wanted = n; \ | |
49 | __p = i->kvec; \ | |
50 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
51 | if (likely(__v.iov_len)) { \ | |
52 | __v.iov_base = __p->iov_base + skip; \ | |
53 | (void)(STEP); \ | |
54 | skip += __v.iov_len; \ | |
55 | n -= __v.iov_len; \ | |
56 | } \ | |
57 | while (unlikely(n)) { \ | |
58 | __p++; \ | |
59 | __v.iov_len = min(n, __p->iov_len); \ | |
60 | if (unlikely(!__v.iov_len)) \ | |
61 | continue; \ | |
62 | __v.iov_base = __p->iov_base; \ | |
63 | (void)(STEP); \ | |
64 | skip = __v.iov_len; \ | |
65 | n -= __v.iov_len; \ | |
66 | } \ | |
67 | n = wanted; \ | |
68 | } | |
69 | ||
1bdc76ae ML |
70 | #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ |
71 | struct bvec_iter __start; \ | |
72 | __start.bi_size = n; \ | |
73 | __start.bi_bvec_done = skip; \ | |
74 | __start.bi_idx = 0; \ | |
75 | for_each_bvec(__v, i->bvec, __bi, __start) { \ | |
04a31165 | 76 | (void)(STEP); \ |
04a31165 | 77 | } \ |
04a31165 AV |
78 | } |
79 | ||
7ff50620 DH |
80 | #define iterate_xarray(i, n, __v, skip, STEP) { \ |
81 | struct page *head = NULL; \ | |
82 | size_t wanted = n, seg, offset; \ | |
83 | loff_t start = i->xarray_start + skip; \ | |
84 | pgoff_t index = start >> PAGE_SHIFT; \ | |
85 | int j; \ | |
86 | \ | |
87 | XA_STATE(xas, i->xarray, index); \ | |
88 | \ | |
89 | rcu_read_lock(); \ | |
90 | xas_for_each(&xas, head, ULONG_MAX) { \ | |
91 | if (xas_retry(&xas, head)) \ | |
92 | continue; \ | |
93 | if (WARN_ON(xa_is_value(head))) \ | |
94 | break; \ | |
95 | if (WARN_ON(PageHuge(head))) \ | |
96 | break; \ | |
97 | for (j = (head->index < index) ? index - head->index : 0; \ | |
98 | j < thp_nr_pages(head); j++) { \ | |
99 | __v.bv_page = head + j; \ | |
100 | offset = (i->xarray_start + skip) & ~PAGE_MASK; \ | |
101 | seg = PAGE_SIZE - offset; \ | |
102 | __v.bv_offset = offset; \ | |
103 | __v.bv_len = min(n, seg); \ | |
104 | (void)(STEP); \ | |
105 | n -= __v.bv_len; \ | |
106 | skip += __v.bv_len; \ | |
107 | if (n == 0) \ | |
108 | break; \ | |
109 | } \ | |
110 | if (n == 0) \ | |
111 | break; \ | |
112 | } \ | |
113 | rcu_read_unlock(); \ | |
114 | n = wanted - n; \ | |
115 | } | |
116 | ||
117 | #define iterate_all_kinds(i, n, v, I, B, K, X) { \ | |
33844e66 AV |
118 | if (likely(n)) { \ |
119 | size_t skip = i->iov_offset; \ | |
28f38db7 AV |
120 | if (likely(iter_is_iovec(i))) { \ |
121 | const struct iovec *iov; \ | |
122 | struct iovec v; \ | |
123 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
124 | } else if (iov_iter_is_bvec(i)) { \ | |
33844e66 AV |
125 | struct bio_vec v; \ |
126 | struct bvec_iter __bi; \ | |
127 | iterate_bvec(i, n, v, __bi, skip, (B)) \ | |
28f38db7 | 128 | } else if (iov_iter_is_kvec(i)) { \ |
33844e66 AV |
129 | const struct kvec *kvec; \ |
130 | struct kvec v; \ | |
131 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
28f38db7 | 132 | } else if (iov_iter_is_xarray(i)) { \ |
7ff50620 DH |
133 | struct bio_vec v; \ |
134 | iterate_xarray(i, n, v, skip, (X)); \ | |
33844e66 | 135 | } \ |
04a31165 AV |
136 | } \ |
137 | } | |
138 | ||
7ff50620 | 139 | #define iterate_and_advance(i, n, v, I, B, K, X) { \ |
dd254f5a AV |
140 | if (unlikely(i->count < n)) \ |
141 | n = i->count; \ | |
19f18459 | 142 | if (i->count) { \ |
dd254f5a | 143 | size_t skip = i->iov_offset; \ |
28f38db7 AV |
144 | if (likely(iter_is_iovec(i))) { \ |
145 | const struct iovec *iov; \ | |
146 | struct iovec v; \ | |
147 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
148 | if (skip == iov->iov_len) { \ | |
149 | iov++; \ | |
150 | skip = 0; \ | |
151 | } \ | |
152 | i->nr_segs -= iov - i->iov; \ | |
153 | i->iov = iov; \ | |
154 | } else if (iov_iter_is_bvec(i)) { \ | |
1bdc76ae | 155 | const struct bio_vec *bvec = i->bvec; \ |
dd254f5a | 156 | struct bio_vec v; \ |
1bdc76ae ML |
157 | struct bvec_iter __bi; \ |
158 | iterate_bvec(i, n, v, __bi, skip, (B)) \ | |
159 | i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ | |
160 | i->nr_segs -= i->bvec - bvec; \ | |
161 | skip = __bi.bi_bvec_done; \ | |
28f38db7 | 162 | } else if (iov_iter_is_kvec(i)) { \ |
dd254f5a AV |
163 | const struct kvec *kvec; \ |
164 | struct kvec v; \ | |
165 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
166 | if (skip == kvec->iov_len) { \ | |
167 | kvec++; \ | |
168 | skip = 0; \ | |
169 | } \ | |
170 | i->nr_segs -= kvec - i->kvec; \ | |
171 | i->kvec = kvec; \ | |
28f38db7 | 172 | } else if (iov_iter_is_xarray(i)) { \ |
7ff50620 DH |
173 | struct bio_vec v; \ |
174 | iterate_xarray(i, n, v, skip, (X)) \ | |
7ce2a91e | 175 | } \ |
dd254f5a AV |
176 | i->count -= n; \ |
177 | i->iov_offset = skip; \ | |
7ce2a91e | 178 | } \ |
7ce2a91e AV |
179 | } |
180 | ||
09fc68dc AV |
181 | static int copyout(void __user *to, const void *from, size_t n) |
182 | { | |
4d0e9df5 AL |
183 | if (should_fail_usercopy()) |
184 | return n; | |
96d4f267 | 185 | if (access_ok(to, n)) { |
d0ef4c36 | 186 | instrument_copy_to_user(to, from, n); |
09fc68dc AV |
187 | n = raw_copy_to_user(to, from, n); |
188 | } | |
189 | return n; | |
190 | } | |
191 | ||
192 | static int copyin(void *to, const void __user *from, size_t n) | |
193 | { | |
4d0e9df5 AL |
194 | if (should_fail_usercopy()) |
195 | return n; | |
96d4f267 | 196 | if (access_ok(from, n)) { |
d0ef4c36 | 197 | instrument_copy_from_user(to, from, n); |
09fc68dc AV |
198 | n = raw_copy_from_user(to, from, n); |
199 | } | |
200 | return n; | |
201 | } | |
202 | ||
62a8067a | 203 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
204 | struct iov_iter *i) |
205 | { | |
206 | size_t skip, copy, left, wanted; | |
207 | const struct iovec *iov; | |
208 | char __user *buf; | |
209 | void *kaddr, *from; | |
210 | ||
211 | if (unlikely(bytes > i->count)) | |
212 | bytes = i->count; | |
213 | ||
214 | if (unlikely(!bytes)) | |
215 | return 0; | |
216 | ||
09fc68dc | 217 | might_fault(); |
4f18cd31 AV |
218 | wanted = bytes; |
219 | iov = i->iov; | |
220 | skip = i->iov_offset; | |
221 | buf = iov->iov_base + skip; | |
222 | copy = min(bytes, iov->iov_len - skip); | |
223 | ||
3fa6c507 | 224 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { |
4f18cd31 AV |
225 | kaddr = kmap_atomic(page); |
226 | from = kaddr + offset; | |
227 | ||
228 | /* first chunk, usually the only one */ | |
09fc68dc | 229 | left = copyout(buf, from, copy); |
4f18cd31 AV |
230 | copy -= left; |
231 | skip += copy; | |
232 | from += copy; | |
233 | bytes -= copy; | |
234 | ||
235 | while (unlikely(!left && bytes)) { | |
236 | iov++; | |
237 | buf = iov->iov_base; | |
238 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 239 | left = copyout(buf, from, copy); |
4f18cd31 AV |
240 | copy -= left; |
241 | skip = copy; | |
242 | from += copy; | |
243 | bytes -= copy; | |
244 | } | |
245 | if (likely(!bytes)) { | |
246 | kunmap_atomic(kaddr); | |
247 | goto done; | |
248 | } | |
249 | offset = from - kaddr; | |
250 | buf += copy; | |
251 | kunmap_atomic(kaddr); | |
252 | copy = min(bytes, iov->iov_len - skip); | |
253 | } | |
254 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 255 | |
4f18cd31 AV |
256 | kaddr = kmap(page); |
257 | from = kaddr + offset; | |
09fc68dc | 258 | left = copyout(buf, from, copy); |
4f18cd31 AV |
259 | copy -= left; |
260 | skip += copy; | |
261 | from += copy; | |
262 | bytes -= copy; | |
263 | while (unlikely(!left && bytes)) { | |
264 | iov++; | |
265 | buf = iov->iov_base; | |
266 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 267 | left = copyout(buf, from, copy); |
4f18cd31 AV |
268 | copy -= left; |
269 | skip = copy; | |
270 | from += copy; | |
271 | bytes -= copy; | |
272 | } | |
273 | kunmap(page); | |
3fa6c507 | 274 | |
4f18cd31 | 275 | done: |
81055e58 AV |
276 | if (skip == iov->iov_len) { |
277 | iov++; | |
278 | skip = 0; | |
279 | } | |
4f18cd31 AV |
280 | i->count -= wanted - bytes; |
281 | i->nr_segs -= iov - i->iov; | |
282 | i->iov = iov; | |
283 | i->iov_offset = skip; | |
284 | return wanted - bytes; | |
285 | } | |
4f18cd31 | 286 | |
62a8067a | 287 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
288 | struct iov_iter *i) |
289 | { | |
290 | size_t skip, copy, left, wanted; | |
291 | const struct iovec *iov; | |
292 | char __user *buf; | |
293 | void *kaddr, *to; | |
294 | ||
295 | if (unlikely(bytes > i->count)) | |
296 | bytes = i->count; | |
297 | ||
298 | if (unlikely(!bytes)) | |
299 | return 0; | |
300 | ||
09fc68dc | 301 | might_fault(); |
f0d1bec9 AV |
302 | wanted = bytes; |
303 | iov = i->iov; | |
304 | skip = i->iov_offset; | |
305 | buf = iov->iov_base + skip; | |
306 | copy = min(bytes, iov->iov_len - skip); | |
307 | ||
3fa6c507 | 308 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { |
f0d1bec9 AV |
309 | kaddr = kmap_atomic(page); |
310 | to = kaddr + offset; | |
311 | ||
312 | /* first chunk, usually the only one */ | |
09fc68dc | 313 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
314 | copy -= left; |
315 | skip += copy; | |
316 | to += copy; | |
317 | bytes -= copy; | |
318 | ||
319 | while (unlikely(!left && bytes)) { | |
320 | iov++; | |
321 | buf = iov->iov_base; | |
322 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 323 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
324 | copy -= left; |
325 | skip = copy; | |
326 | to += copy; | |
327 | bytes -= copy; | |
328 | } | |
329 | if (likely(!bytes)) { | |
330 | kunmap_atomic(kaddr); | |
331 | goto done; | |
332 | } | |
333 | offset = to - kaddr; | |
334 | buf += copy; | |
335 | kunmap_atomic(kaddr); | |
336 | copy = min(bytes, iov->iov_len - skip); | |
337 | } | |
338 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 339 | |
f0d1bec9 AV |
340 | kaddr = kmap(page); |
341 | to = kaddr + offset; | |
09fc68dc | 342 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
343 | copy -= left; |
344 | skip += copy; | |
345 | to += copy; | |
346 | bytes -= copy; | |
347 | while (unlikely(!left && bytes)) { | |
348 | iov++; | |
349 | buf = iov->iov_base; | |
350 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 351 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
352 | copy -= left; |
353 | skip = copy; | |
354 | to += copy; | |
355 | bytes -= copy; | |
356 | } | |
357 | kunmap(page); | |
3fa6c507 | 358 | |
f0d1bec9 | 359 | done: |
81055e58 AV |
360 | if (skip == iov->iov_len) { |
361 | iov++; | |
362 | skip = 0; | |
363 | } | |
f0d1bec9 AV |
364 | i->count -= wanted - bytes; |
365 | i->nr_segs -= iov - i->iov; | |
366 | i->iov = iov; | |
367 | i->iov_offset = skip; | |
368 | return wanted - bytes; | |
369 | } | |
f0d1bec9 | 370 | |
241699cd AV |
371 | #ifdef PIPE_PARANOIA |
372 | static bool sanity(const struct iov_iter *i) | |
373 | { | |
374 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
375 | unsigned int p_head = pipe->head; |
376 | unsigned int p_tail = pipe->tail; | |
377 | unsigned int p_mask = pipe->ring_size - 1; | |
378 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); | |
379 | unsigned int i_head = i->head; | |
380 | unsigned int idx; | |
381 | ||
241699cd AV |
382 | if (i->iov_offset) { |
383 | struct pipe_buffer *p; | |
8cefc107 | 384 | if (unlikely(p_occupancy == 0)) |
241699cd | 385 | goto Bad; // pipe must be non-empty |
8cefc107 | 386 | if (unlikely(i_head != p_head - 1)) |
241699cd AV |
387 | goto Bad; // must be at the last buffer... |
388 | ||
8cefc107 | 389 | p = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
390 | if (unlikely(p->offset + p->len != i->iov_offset)) |
391 | goto Bad; // ... at the end of segment | |
392 | } else { | |
8cefc107 | 393 | if (i_head != p_head) |
241699cd AV |
394 | goto Bad; // must be right after the last buffer |
395 | } | |
396 | return true; | |
397 | Bad: | |
8cefc107 DH |
398 | printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); |
399 | printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", | |
400 | p_head, p_tail, pipe->ring_size); | |
401 | for (idx = 0; idx < pipe->ring_size; idx++) | |
241699cd AV |
402 | printk(KERN_ERR "[%p %p %d %d]\n", |
403 | pipe->bufs[idx].ops, | |
404 | pipe->bufs[idx].page, | |
405 | pipe->bufs[idx].offset, | |
406 | pipe->bufs[idx].len); | |
407 | WARN_ON(1); | |
408 | return false; | |
409 | } | |
410 | #else | |
411 | #define sanity(i) true | |
412 | #endif | |
413 | ||
241699cd AV |
414 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
415 | struct iov_iter *i) | |
416 | { | |
417 | struct pipe_inode_info *pipe = i->pipe; | |
418 | struct pipe_buffer *buf; | |
8cefc107 DH |
419 | unsigned int p_tail = pipe->tail; |
420 | unsigned int p_mask = pipe->ring_size - 1; | |
421 | unsigned int i_head = i->head; | |
241699cd | 422 | size_t off; |
241699cd AV |
423 | |
424 | if (unlikely(bytes > i->count)) | |
425 | bytes = i->count; | |
426 | ||
427 | if (unlikely(!bytes)) | |
428 | return 0; | |
429 | ||
430 | if (!sanity(i)) | |
431 | return 0; | |
432 | ||
433 | off = i->iov_offset; | |
8cefc107 | 434 | buf = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
435 | if (off) { |
436 | if (offset == off && buf->page == page) { | |
437 | /* merge with the last one */ | |
438 | buf->len += bytes; | |
439 | i->iov_offset += bytes; | |
440 | goto out; | |
441 | } | |
8cefc107 DH |
442 | i_head++; |
443 | buf = &pipe->bufs[i_head & p_mask]; | |
241699cd | 444 | } |
6718b6f8 | 445 | if (pipe_full(i_head, p_tail, pipe->max_usage)) |
241699cd | 446 | return 0; |
8cefc107 | 447 | |
241699cd | 448 | buf->ops = &page_cache_pipe_buf_ops; |
8cefc107 DH |
449 | get_page(page); |
450 | buf->page = page; | |
241699cd AV |
451 | buf->offset = offset; |
452 | buf->len = bytes; | |
8cefc107 DH |
453 | |
454 | pipe->head = i_head + 1; | |
241699cd | 455 | i->iov_offset = offset + bytes; |
8cefc107 | 456 | i->head = i_head; |
241699cd AV |
457 | out: |
458 | i->count -= bytes; | |
459 | return bytes; | |
460 | } | |
461 | ||
171a0203 AA |
462 | /* |
463 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of | |
464 | * bytes. For each iovec, fault in each page that constitutes the iovec. | |
465 | * | |
466 | * Return 0 on success, or non-zero if the memory could not be accessed (i.e. | |
467 | * because it is an invalid address). | |
468 | */ | |
8409a0d2 | 469 | int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) |
171a0203 | 470 | { |
0e8f0d67 | 471 | if (iter_is_iovec(i)) { |
8409a0d2 AV |
472 | const struct iovec *p; |
473 | size_t skip; | |
474 | ||
475 | if (bytes > i->count) | |
476 | bytes = i->count; | |
477 | for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { | |
478 | size_t len = min(bytes, p->iov_len - skip); | |
479 | int err; | |
480 | ||
481 | if (unlikely(!len)) | |
482 | continue; | |
483 | err = fault_in_pages_readable(p->iov_base + skip, len); | |
171a0203 | 484 | if (unlikely(err)) |
8409a0d2 AV |
485 | return err; |
486 | bytes -= len; | |
487 | } | |
171a0203 AA |
488 | } |
489 | return 0; | |
490 | } | |
d4690f1e | 491 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
171a0203 | 492 | |
aa563d7b | 493 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
494 | const struct iovec *iov, unsigned long nr_segs, |
495 | size_t count) | |
496 | { | |
aa563d7b | 497 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
498 | WARN_ON_ONCE(uaccess_kernel()); |
499 | *i = (struct iov_iter) { | |
500 | .iter_type = ITER_IOVEC, | |
501 | .data_source = direction, | |
502 | .iov = iov, | |
503 | .nr_segs = nr_segs, | |
504 | .iov_offset = 0, | |
505 | .count = count | |
506 | }; | |
71d8e532 AV |
507 | } |
508 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 509 | |
241699cd AV |
510 | static inline bool allocated(struct pipe_buffer *buf) |
511 | { | |
512 | return buf->ops == &default_pipe_buf_ops; | |
513 | } | |
514 | ||
8cefc107 DH |
515 | static inline void data_start(const struct iov_iter *i, |
516 | unsigned int *iter_headp, size_t *offp) | |
241699cd | 517 | { |
8cefc107 DH |
518 | unsigned int p_mask = i->pipe->ring_size - 1; |
519 | unsigned int iter_head = i->head; | |
241699cd | 520 | size_t off = i->iov_offset; |
8cefc107 DH |
521 | |
522 | if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || | |
523 | off == PAGE_SIZE)) { | |
524 | iter_head++; | |
241699cd AV |
525 | off = 0; |
526 | } | |
8cefc107 | 527 | *iter_headp = iter_head; |
241699cd AV |
528 | *offp = off; |
529 | } | |
530 | ||
531 | static size_t push_pipe(struct iov_iter *i, size_t size, | |
8cefc107 | 532 | int *iter_headp, size_t *offp) |
241699cd AV |
533 | { |
534 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
535 | unsigned int p_tail = pipe->tail; |
536 | unsigned int p_mask = pipe->ring_size - 1; | |
537 | unsigned int iter_head; | |
241699cd | 538 | size_t off; |
241699cd AV |
539 | ssize_t left; |
540 | ||
541 | if (unlikely(size > i->count)) | |
542 | size = i->count; | |
543 | if (unlikely(!size)) | |
544 | return 0; | |
545 | ||
546 | left = size; | |
8cefc107 DH |
547 | data_start(i, &iter_head, &off); |
548 | *iter_headp = iter_head; | |
241699cd AV |
549 | *offp = off; |
550 | if (off) { | |
551 | left -= PAGE_SIZE - off; | |
552 | if (left <= 0) { | |
8cefc107 | 553 | pipe->bufs[iter_head & p_mask].len += size; |
241699cd AV |
554 | return size; |
555 | } | |
8cefc107 DH |
556 | pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; |
557 | iter_head++; | |
241699cd | 558 | } |
6718b6f8 | 559 | while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { |
8cefc107 | 560 | struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; |
241699cd AV |
561 | struct page *page = alloc_page(GFP_USER); |
562 | if (!page) | |
563 | break; | |
8cefc107 DH |
564 | |
565 | buf->ops = &default_pipe_buf_ops; | |
566 | buf->page = page; | |
567 | buf->offset = 0; | |
568 | buf->len = min_t(ssize_t, left, PAGE_SIZE); | |
569 | left -= buf->len; | |
570 | iter_head++; | |
571 | pipe->head = iter_head; | |
572 | ||
573 | if (left == 0) | |
241699cd | 574 | return size; |
241699cd AV |
575 | } |
576 | return size - left; | |
577 | } | |
578 | ||
579 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, | |
580 | struct iov_iter *i) | |
581 | { | |
582 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
583 | unsigned int p_mask = pipe->ring_size - 1; |
584 | unsigned int i_head; | |
241699cd | 585 | size_t n, off; |
241699cd AV |
586 | |
587 | if (!sanity(i)) | |
588 | return 0; | |
589 | ||
8cefc107 | 590 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
591 | if (unlikely(!n)) |
592 | return 0; | |
8cefc107 | 593 | do { |
241699cd | 594 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
595 | memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); |
596 | i->head = i_head; | |
241699cd AV |
597 | i->iov_offset = off + chunk; |
598 | n -= chunk; | |
599 | addr += chunk; | |
8cefc107 DH |
600 | off = 0; |
601 | i_head++; | |
602 | } while (n); | |
241699cd AV |
603 | i->count -= bytes; |
604 | return bytes; | |
605 | } | |
606 | ||
f9152895 AV |
607 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
608 | __wsum sum, size_t off) | |
609 | { | |
cc44c17b | 610 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
f9152895 AV |
611 | return csum_block_add(sum, next, off); |
612 | } | |
613 | ||
78e1f386 | 614 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
52cbd23a WB |
615 | struct csum_state *csstate, |
616 | struct iov_iter *i) | |
78e1f386 AV |
617 | { |
618 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 | 619 | unsigned int p_mask = pipe->ring_size - 1; |
52cbd23a WB |
620 | __wsum sum = csstate->csum; |
621 | size_t off = csstate->off; | |
8cefc107 | 622 | unsigned int i_head; |
78e1f386 | 623 | size_t n, r; |
78e1f386 AV |
624 | |
625 | if (!sanity(i)) | |
626 | return 0; | |
627 | ||
8cefc107 | 628 | bytes = n = push_pipe(i, bytes, &i_head, &r); |
78e1f386 AV |
629 | if (unlikely(!n)) |
630 | return 0; | |
8cefc107 | 631 | do { |
78e1f386 | 632 | size_t chunk = min_t(size_t, n, PAGE_SIZE - r); |
8cefc107 | 633 | char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); |
f9152895 | 634 | sum = csum_and_memcpy(p + r, addr, chunk, sum, off); |
78e1f386 | 635 | kunmap_atomic(p); |
8cefc107 | 636 | i->head = i_head; |
78e1f386 AV |
637 | i->iov_offset = r + chunk; |
638 | n -= chunk; | |
639 | off += chunk; | |
640 | addr += chunk; | |
8cefc107 DH |
641 | r = 0; |
642 | i_head++; | |
643 | } while (n); | |
78e1f386 | 644 | i->count -= bytes; |
52cbd23a WB |
645 | csstate->csum = sum; |
646 | csstate->off = off; | |
78e1f386 AV |
647 | return bytes; |
648 | } | |
649 | ||
aa28de27 | 650 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 651 | { |
36f7a8a4 | 652 | const char *from = addr; |
00e23707 | 653 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 654 | return copy_pipe_to_iter(addr, bytes, i); |
09fc68dc AV |
655 | if (iter_is_iovec(i)) |
656 | might_fault(); | |
3d4d3e48 | 657 | iterate_and_advance(i, bytes, v, |
09fc68dc | 658 | copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
3d4d3e48 | 659 | memcpy_to_page(v.bv_page, v.bv_offset, |
a280455f | 660 | (from += v.bv_len) - v.bv_len, v.bv_len), |
7ff50620 DH |
661 | memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
662 | memcpy_to_page(v.bv_page, v.bv_offset, | |
663 | (from += v.bv_len) - v.bv_len, v.bv_len) | |
3d4d3e48 | 664 | ) |
62a8067a | 665 | |
3d4d3e48 | 666 | return bytes; |
c35e0248 | 667 | } |
aa28de27 | 668 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 669 | |
ec6347bb DW |
670 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
671 | static int copyout_mc(void __user *to, const void *from, size_t n) | |
8780356e | 672 | { |
96d4f267 | 673 | if (access_ok(to, n)) { |
d0ef4c36 | 674 | instrument_copy_to_user(to, from, n); |
ec6347bb | 675 | n = copy_mc_to_user((__force void *) to, from, n); |
8780356e DW |
676 | } |
677 | return n; | |
678 | } | |
679 | ||
ec6347bb | 680 | static unsigned long copy_mc_to_page(struct page *page, size_t offset, |
8780356e DW |
681 | const char *from, size_t len) |
682 | { | |
683 | unsigned long ret; | |
684 | char *to; | |
685 | ||
686 | to = kmap_atomic(page); | |
ec6347bb | 687 | ret = copy_mc_to_kernel(to + offset, from, len); |
8780356e DW |
688 | kunmap_atomic(to); |
689 | ||
690 | return ret; | |
691 | } | |
692 | ||
ec6347bb | 693 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
ca146f6f DW |
694 | struct iov_iter *i) |
695 | { | |
696 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
697 | unsigned int p_mask = pipe->ring_size - 1; |
698 | unsigned int i_head; | |
ca146f6f | 699 | size_t n, off, xfer = 0; |
ca146f6f DW |
700 | |
701 | if (!sanity(i)) | |
702 | return 0; | |
703 | ||
8cefc107 | 704 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
ca146f6f DW |
705 | if (unlikely(!n)) |
706 | return 0; | |
8cefc107 | 707 | do { |
ca146f6f DW |
708 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
709 | unsigned long rem; | |
710 | ||
ec6347bb | 711 | rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, |
8cefc107 DH |
712 | off, addr, chunk); |
713 | i->head = i_head; | |
ca146f6f DW |
714 | i->iov_offset = off + chunk - rem; |
715 | xfer += chunk - rem; | |
716 | if (rem) | |
717 | break; | |
718 | n -= chunk; | |
719 | addr += chunk; | |
8cefc107 DH |
720 | off = 0; |
721 | i_head++; | |
722 | } while (n); | |
ca146f6f DW |
723 | i->count -= xfer; |
724 | return xfer; | |
725 | } | |
726 | ||
bf3eeb9b | 727 | /** |
ec6347bb | 728 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
bf3eeb9b DW |
729 | * @addr: source kernel address |
730 | * @bytes: total transfer length | |
731 | * @iter: destination iterator | |
732 | * | |
ec6347bb DW |
733 | * The pmem driver deploys this for the dax operation |
734 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the | |
735 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes | |
736 | * successfully copied. | |
bf3eeb9b | 737 | * |
ec6347bb | 738 | * The main differences between this and typical _copy_to_iter(). |
bf3eeb9b DW |
739 | * |
740 | * * Typical tail/residue handling after a fault retries the copy | |
741 | * byte-by-byte until the fault happens again. Re-triggering machine | |
742 | * checks is potentially fatal so the implementation uses source | |
743 | * alignment and poison alignment assumptions to avoid re-triggering | |
744 | * hardware exceptions. | |
745 | * | |
746 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. | |
747 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return | |
748 | * a short copy. | |
bf3eeb9b | 749 | */ |
ec6347bb | 750 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
8780356e DW |
751 | { |
752 | const char *from = addr; | |
753 | unsigned long rem, curr_addr, s_addr = (unsigned long) addr; | |
754 | ||
00e23707 | 755 | if (unlikely(iov_iter_is_pipe(i))) |
ec6347bb | 756 | return copy_mc_pipe_to_iter(addr, bytes, i); |
8780356e DW |
757 | if (iter_is_iovec(i)) |
758 | might_fault(); | |
759 | iterate_and_advance(i, bytes, v, | |
ec6347bb DW |
760 | copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, |
761 | v.iov_len), | |
8780356e | 762 | ({ |
ec6347bb DW |
763 | rem = copy_mc_to_page(v.bv_page, v.bv_offset, |
764 | (from += v.bv_len) - v.bv_len, v.bv_len); | |
8780356e DW |
765 | if (rem) { |
766 | curr_addr = (unsigned long) from; | |
767 | bytes = curr_addr - s_addr - rem; | |
768 | return bytes; | |
769 | } | |
770 | }), | |
771 | ({ | |
ec6347bb DW |
772 | rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) |
773 | - v.iov_len, v.iov_len); | |
8780356e DW |
774 | if (rem) { |
775 | curr_addr = (unsigned long) from; | |
776 | bytes = curr_addr - s_addr - rem; | |
777 | return bytes; | |
778 | } | |
7ff50620 DH |
779 | }), |
780 | ({ | |
781 | rem = copy_mc_to_page(v.bv_page, v.bv_offset, | |
782 | (from += v.bv_len) - v.bv_len, v.bv_len); | |
783 | if (rem) { | |
784 | curr_addr = (unsigned long) from; | |
785 | bytes = curr_addr - s_addr - rem; | |
786 | rcu_read_unlock(); | |
3d14ec1f DH |
787 | i->iov_offset += bytes; |
788 | i->count -= bytes; | |
7ff50620 DH |
789 | return bytes; |
790 | } | |
8780356e DW |
791 | }) |
792 | ) | |
793 | ||
794 | return bytes; | |
795 | } | |
ec6347bb DW |
796 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
797 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 798 | |
aa28de27 | 799 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 800 | { |
0dbca9a4 | 801 | char *to = addr; |
00e23707 | 802 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
803 | WARN_ON(1); |
804 | return 0; | |
805 | } | |
09fc68dc AV |
806 | if (iter_is_iovec(i)) |
807 | might_fault(); | |
0dbca9a4 | 808 | iterate_and_advance(i, bytes, v, |
09fc68dc | 809 | copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
0dbca9a4 | 810 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 811 | v.bv_offset, v.bv_len), |
7ff50620 DH |
812 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
813 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
814 | v.bv_offset, v.bv_len) | |
0dbca9a4 AV |
815 | ) |
816 | ||
817 | return bytes; | |
c35e0248 | 818 | } |
aa28de27 | 819 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 820 | |
aa28de27 | 821 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 AV |
822 | { |
823 | char *to = addr; | |
00e23707 | 824 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
825 | WARN_ON(1); |
826 | return 0; | |
827 | } | |
aa583096 | 828 | iterate_and_advance(i, bytes, v, |
3f763453 | 829 | __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
aa583096 AV |
830 | v.iov_base, v.iov_len), |
831 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
832 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
833 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
834 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
835 | v.bv_offset, v.bv_len) | |
aa583096 AV |
836 | ) |
837 | ||
838 | return bytes; | |
839 | } | |
aa28de27 | 840 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 841 | |
0aed55af | 842 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
843 | /** |
844 | * _copy_from_iter_flushcache - write destination through cpu cache | |
845 | * @addr: destination kernel address | |
846 | * @bytes: total transfer length | |
847 | * @iter: source iterator | |
848 | * | |
849 | * The pmem driver arranges for filesystem-dax to use this facility via | |
850 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
851 | * are flushed through the CPU cache. It is differentiated from | |
852 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
853 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
854 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
855 | * instructions that strand dirty-data in the cache. | |
856 | */ | |
6a37e940 | 857 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af DW |
858 | { |
859 | char *to = addr; | |
00e23707 | 860 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
861 | WARN_ON(1); |
862 | return 0; | |
863 | } | |
864 | iterate_and_advance(i, bytes, v, | |
865 | __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, | |
866 | v.iov_base, v.iov_len), | |
867 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
868 | v.bv_offset, v.bv_len), | |
869 | memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, | |
7ff50620 DH |
870 | v.iov_len), |
871 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
872 | v.bv_offset, v.bv_len) | |
0aed55af DW |
873 | ) |
874 | ||
875 | return bytes; | |
876 | } | |
6a37e940 | 877 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
878 | #endif |
879 | ||
72e809ed AV |
880 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
881 | { | |
6daef95b ED |
882 | struct page *head; |
883 | size_t v = n + offset; | |
884 | ||
885 | /* | |
886 | * The general case needs to access the page order in order | |
887 | * to compute the page size. | |
888 | * However, we mostly deal with order-0 pages and thus can | |
889 | * avoid a possible cache line miss for requests that fit all | |
890 | * page orders. | |
891 | */ | |
892 | if (n <= v && v <= PAGE_SIZE) | |
893 | return true; | |
894 | ||
895 | head = compound_head(page); | |
896 | v += (page - head) << PAGE_SHIFT; | |
a90bcb86 | 897 | |
a50b854e | 898 | if (likely(n <= v && v <= (page_size(head)))) |
72e809ed AV |
899 | return true; |
900 | WARN_ON(1); | |
901 | return false; | |
902 | } | |
cbbd26b8 | 903 | |
08aa6479 | 904 | static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
62a8067a AV |
905 | struct iov_iter *i) |
906 | { | |
28f38db7 AV |
907 | if (likely(iter_is_iovec(i))) |
908 | return copy_page_to_iter_iovec(page, offset, bytes, i); | |
909 | if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { | |
d271524a AV |
910 | void *kaddr = kmap_atomic(page); |
911 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); | |
912 | kunmap_atomic(kaddr); | |
913 | return wanted; | |
28f38db7 AV |
914 | } |
915 | if (iov_iter_is_pipe(i)) | |
916 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
917 | if (unlikely(iov_iter_is_discard(i))) { | |
a506abc7 AV |
918 | if (unlikely(i->count < bytes)) |
919 | bytes = i->count; | |
920 | i->count -= bytes; | |
9ea9ce04 | 921 | return bytes; |
28f38db7 AV |
922 | } |
923 | WARN_ON(1); | |
924 | return 0; | |
62a8067a | 925 | } |
08aa6479 AV |
926 | |
927 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, | |
928 | struct iov_iter *i) | |
929 | { | |
930 | size_t res = 0; | |
931 | if (unlikely(!page_copy_sane(page, offset, bytes))) | |
932 | return 0; | |
933 | page += offset / PAGE_SIZE; // first subpage | |
934 | offset %= PAGE_SIZE; | |
935 | while (1) { | |
936 | size_t n = __copy_page_to_iter(page, offset, | |
937 | min(bytes, (size_t)PAGE_SIZE - offset), i); | |
938 | res += n; | |
939 | bytes -= n; | |
940 | if (!bytes || !n) | |
941 | break; | |
942 | offset += n; | |
943 | if (offset == PAGE_SIZE) { | |
944 | page++; | |
945 | offset = 0; | |
946 | } | |
947 | } | |
948 | return res; | |
949 | } | |
62a8067a AV |
950 | EXPORT_SYMBOL(copy_page_to_iter); |
951 | ||
952 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
953 | struct iov_iter *i) | |
954 | { | |
72e809ed AV |
955 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
956 | return 0; | |
28f38db7 AV |
957 | if (likely(iter_is_iovec(i))) |
958 | return copy_page_from_iter_iovec(page, offset, bytes, i); | |
959 | if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { | |
d271524a | 960 | void *kaddr = kmap_atomic(page); |
aa28de27 | 961 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
d271524a AV |
962 | kunmap_atomic(kaddr); |
963 | return wanted; | |
28f38db7 AV |
964 | } |
965 | WARN_ON(1); | |
966 | return 0; | |
62a8067a AV |
967 | } |
968 | EXPORT_SYMBOL(copy_page_from_iter); | |
969 | ||
241699cd AV |
970 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
971 | { | |
972 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
973 | unsigned int p_mask = pipe->ring_size - 1; |
974 | unsigned int i_head; | |
241699cd | 975 | size_t n, off; |
241699cd AV |
976 | |
977 | if (!sanity(i)) | |
978 | return 0; | |
979 | ||
8cefc107 | 980 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
981 | if (unlikely(!n)) |
982 | return 0; | |
983 | ||
8cefc107 | 984 | do { |
241699cd | 985 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
986 | memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); |
987 | i->head = i_head; | |
241699cd AV |
988 | i->iov_offset = off + chunk; |
989 | n -= chunk; | |
8cefc107 DH |
990 | off = 0; |
991 | i_head++; | |
992 | } while (n); | |
241699cd AV |
993 | i->count -= bytes; |
994 | return bytes; | |
995 | } | |
996 | ||
c35e0248 MW |
997 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
998 | { | |
00e23707 | 999 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1000 | return pipe_zero(bytes, i); |
8442fa46 | 1001 | iterate_and_advance(i, bytes, v, |
09fc68dc | 1002 | clear_user(v.iov_base, v.iov_len), |
a280455f | 1003 | memzero_page(v.bv_page, v.bv_offset, v.bv_len), |
7ff50620 DH |
1004 | memset(v.iov_base, 0, v.iov_len), |
1005 | memzero_page(v.bv_page, v.bv_offset, v.bv_len) | |
8442fa46 AV |
1006 | ) |
1007 | ||
1008 | return bytes; | |
c35e0248 MW |
1009 | } |
1010 | EXPORT_SYMBOL(iov_iter_zero); | |
1011 | ||
62a8067a AV |
1012 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
1013 | struct iov_iter *i, unsigned long offset, size_t bytes) | |
1014 | { | |
04a31165 | 1015 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
1016 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
1017 | kunmap_atomic(kaddr); | |
1018 | return 0; | |
1019 | } | |
9ea9ce04 | 1020 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1021 | kunmap_atomic(kaddr); |
1022 | WARN_ON(1); | |
1023 | return 0; | |
1024 | } | |
04a31165 | 1025 | iterate_all_kinds(i, bytes, v, |
09fc68dc | 1026 | copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
04a31165 | 1027 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 1028 | v.bv_offset, v.bv_len), |
7ff50620 DH |
1029 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
1030 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, | |
1031 | v.bv_offset, v.bv_len) | |
04a31165 AV |
1032 | ) |
1033 | kunmap_atomic(kaddr); | |
1034 | return bytes; | |
62a8067a AV |
1035 | } |
1036 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); | |
1037 | ||
b9dc6f65 AV |
1038 | static inline void pipe_truncate(struct iov_iter *i) |
1039 | { | |
1040 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1041 | unsigned int p_tail = pipe->tail; |
1042 | unsigned int p_head = pipe->head; | |
1043 | unsigned int p_mask = pipe->ring_size - 1; | |
1044 | ||
1045 | if (!pipe_empty(p_head, p_tail)) { | |
1046 | struct pipe_buffer *buf; | |
1047 | unsigned int i_head = i->head; | |
b9dc6f65 | 1048 | size_t off = i->iov_offset; |
8cefc107 | 1049 | |
b9dc6f65 | 1050 | if (off) { |
8cefc107 DH |
1051 | buf = &pipe->bufs[i_head & p_mask]; |
1052 | buf->len = off - buf->offset; | |
1053 | i_head++; | |
b9dc6f65 | 1054 | } |
8cefc107 DH |
1055 | while (p_head != i_head) { |
1056 | p_head--; | |
1057 | pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); | |
b9dc6f65 | 1058 | } |
8cefc107 DH |
1059 | |
1060 | pipe->head = p_head; | |
b9dc6f65 AV |
1061 | } |
1062 | } | |
1063 | ||
241699cd AV |
1064 | static void pipe_advance(struct iov_iter *i, size_t size) |
1065 | { | |
1066 | struct pipe_inode_info *pipe = i->pipe; | |
241699cd | 1067 | if (size) { |
b9dc6f65 | 1068 | struct pipe_buffer *buf; |
8cefc107 DH |
1069 | unsigned int p_mask = pipe->ring_size - 1; |
1070 | unsigned int i_head = i->head; | |
b9dc6f65 | 1071 | size_t off = i->iov_offset, left = size; |
8cefc107 | 1072 | |
241699cd | 1073 | if (off) /* make it relative to the beginning of buffer */ |
8cefc107 | 1074 | left += off - pipe->bufs[i_head & p_mask].offset; |
241699cd | 1075 | while (1) { |
8cefc107 | 1076 | buf = &pipe->bufs[i_head & p_mask]; |
b9dc6f65 | 1077 | if (left <= buf->len) |
241699cd | 1078 | break; |
b9dc6f65 | 1079 | left -= buf->len; |
8cefc107 | 1080 | i_head++; |
241699cd | 1081 | } |
8cefc107 | 1082 | i->head = i_head; |
b9dc6f65 | 1083 | i->iov_offset = buf->offset + left; |
241699cd | 1084 | } |
b9dc6f65 AV |
1085 | i->count -= size; |
1086 | /* ... and discard everything past that point */ | |
1087 | pipe_truncate(i); | |
241699cd AV |
1088 | } |
1089 | ||
54c8195b PB |
1090 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
1091 | { | |
1092 | struct bvec_iter bi; | |
1093 | ||
1094 | bi.bi_size = i->count; | |
1095 | bi.bi_bvec_done = i->iov_offset; | |
1096 | bi.bi_idx = 0; | |
1097 | bvec_iter_advance(i->bvec, &bi, size); | |
1098 | ||
1099 | i->bvec += bi.bi_idx; | |
1100 | i->nr_segs -= bi.bi_idx; | |
1101 | i->count = bi.bi_size; | |
1102 | i->iov_offset = bi.bi_bvec_done; | |
1103 | } | |
1104 | ||
185ac4d4 AV |
1105 | static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) |
1106 | { | |
1107 | const struct iovec *iov, *end; | |
1108 | ||
1109 | if (!i->count) | |
1110 | return; | |
1111 | i->count -= size; | |
1112 | ||
1113 | size += i->iov_offset; // from beginning of current segment | |
1114 | for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { | |
1115 | if (likely(size < iov->iov_len)) | |
1116 | break; | |
1117 | size -= iov->iov_len; | |
1118 | } | |
1119 | i->iov_offset = size; | |
1120 | i->nr_segs -= iov - i->iov; | |
1121 | i->iov = iov; | |
1122 | } | |
1123 | ||
62a8067a AV |
1124 | void iov_iter_advance(struct iov_iter *i, size_t size) |
1125 | { | |
3b3fc051 AV |
1126 | if (unlikely(i->count < size)) |
1127 | size = i->count; | |
185ac4d4 AV |
1128 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { |
1129 | /* iovec and kvec have identical layouts */ | |
1130 | iov_iter_iovec_advance(i, size); | |
1131 | } else if (iov_iter_is_bvec(i)) { | |
1132 | iov_iter_bvec_advance(i, size); | |
1133 | } else if (iov_iter_is_pipe(i)) { | |
241699cd | 1134 | pipe_advance(i, size); |
185ac4d4 | 1135 | } else if (unlikely(iov_iter_is_xarray(i))) { |
7ff50620 DH |
1136 | i->iov_offset += size; |
1137 | i->count -= size; | |
185ac4d4 AV |
1138 | } else if (iov_iter_is_discard(i)) { |
1139 | i->count -= size; | |
54c8195b | 1140 | } |
62a8067a AV |
1141 | } |
1142 | EXPORT_SYMBOL(iov_iter_advance); | |
1143 | ||
27c0e374 AV |
1144 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
1145 | { | |
1146 | if (!unroll) | |
1147 | return; | |
5b47d59a AV |
1148 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
1149 | return; | |
27c0e374 | 1150 | i->count += unroll; |
00e23707 | 1151 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 | 1152 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 DH |
1153 | unsigned int p_mask = pipe->ring_size - 1; |
1154 | unsigned int i_head = i->head; | |
27c0e374 AV |
1155 | size_t off = i->iov_offset; |
1156 | while (1) { | |
8cefc107 DH |
1157 | struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; |
1158 | size_t n = off - b->offset; | |
27c0e374 | 1159 | if (unroll < n) { |
4fa55cef | 1160 | off -= unroll; |
27c0e374 AV |
1161 | break; |
1162 | } | |
1163 | unroll -= n; | |
8cefc107 | 1164 | if (!unroll && i_head == i->start_head) { |
27c0e374 AV |
1165 | off = 0; |
1166 | break; | |
1167 | } | |
8cefc107 DH |
1168 | i_head--; |
1169 | b = &pipe->bufs[i_head & p_mask]; | |
1170 | off = b->offset + b->len; | |
27c0e374 AV |
1171 | } |
1172 | i->iov_offset = off; | |
8cefc107 | 1173 | i->head = i_head; |
27c0e374 AV |
1174 | pipe_truncate(i); |
1175 | return; | |
1176 | } | |
9ea9ce04 DH |
1177 | if (unlikely(iov_iter_is_discard(i))) |
1178 | return; | |
27c0e374 AV |
1179 | if (unroll <= i->iov_offset) { |
1180 | i->iov_offset -= unroll; | |
1181 | return; | |
1182 | } | |
1183 | unroll -= i->iov_offset; | |
7ff50620 DH |
1184 | if (iov_iter_is_xarray(i)) { |
1185 | BUG(); /* We should never go beyond the start of the specified | |
1186 | * range since we might then be straying into pages that | |
1187 | * aren't pinned. | |
1188 | */ | |
1189 | } else if (iov_iter_is_bvec(i)) { | |
27c0e374 AV |
1190 | const struct bio_vec *bvec = i->bvec; |
1191 | while (1) { | |
1192 | size_t n = (--bvec)->bv_len; | |
1193 | i->nr_segs++; | |
1194 | if (unroll <= n) { | |
1195 | i->bvec = bvec; | |
1196 | i->iov_offset = n - unroll; | |
1197 | return; | |
1198 | } | |
1199 | unroll -= n; | |
1200 | } | |
1201 | } else { /* same logics for iovec and kvec */ | |
1202 | const struct iovec *iov = i->iov; | |
1203 | while (1) { | |
1204 | size_t n = (--iov)->iov_len; | |
1205 | i->nr_segs++; | |
1206 | if (unroll <= n) { | |
1207 | i->iov = iov; | |
1208 | i->iov_offset = n - unroll; | |
1209 | return; | |
1210 | } | |
1211 | unroll -= n; | |
1212 | } | |
1213 | } | |
1214 | } | |
1215 | EXPORT_SYMBOL(iov_iter_revert); | |
1216 | ||
62a8067a AV |
1217 | /* |
1218 | * Return the count of just the current iov_iter segment. | |
1219 | */ | |
1220 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
1221 | { | |
28f38db7 AV |
1222 | if (i->nr_segs > 1) { |
1223 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1224 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
1225 | if (iov_iter_is_bvec(i)) | |
1226 | return min(i->count, i->bvec->bv_len - i->iov_offset); | |
1227 | } | |
1228 | return i->count; | |
62a8067a AV |
1229 | } |
1230 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
1231 | ||
aa563d7b | 1232 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 1233 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
1234 | size_t count) |
1235 | { | |
aa563d7b | 1236 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
1237 | *i = (struct iov_iter){ |
1238 | .iter_type = ITER_KVEC, | |
1239 | .data_source = direction, | |
1240 | .kvec = kvec, | |
1241 | .nr_segs = nr_segs, | |
1242 | .iov_offset = 0, | |
1243 | .count = count | |
1244 | }; | |
abb78f87 AV |
1245 | } |
1246 | EXPORT_SYMBOL(iov_iter_kvec); | |
1247 | ||
aa563d7b | 1248 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1249 | const struct bio_vec *bvec, unsigned long nr_segs, |
1250 | size_t count) | |
1251 | { | |
aa563d7b | 1252 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
1253 | *i = (struct iov_iter){ |
1254 | .iter_type = ITER_BVEC, | |
1255 | .data_source = direction, | |
1256 | .bvec = bvec, | |
1257 | .nr_segs = nr_segs, | |
1258 | .iov_offset = 0, | |
1259 | .count = count | |
1260 | }; | |
05afcb77 AV |
1261 | } |
1262 | EXPORT_SYMBOL(iov_iter_bvec); | |
1263 | ||
aa563d7b | 1264 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1265 | struct pipe_inode_info *pipe, |
1266 | size_t count) | |
1267 | { | |
aa563d7b | 1268 | BUG_ON(direction != READ); |
8cefc107 | 1269 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
8cd54c1c AV |
1270 | *i = (struct iov_iter){ |
1271 | .iter_type = ITER_PIPE, | |
1272 | .data_source = false, | |
1273 | .pipe = pipe, | |
1274 | .head = pipe->head, | |
1275 | .start_head = pipe->head, | |
1276 | .iov_offset = 0, | |
1277 | .count = count | |
1278 | }; | |
241699cd AV |
1279 | } |
1280 | EXPORT_SYMBOL(iov_iter_pipe); | |
1281 | ||
7ff50620 DH |
1282 | /** |
1283 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray | |
1284 | * @i: The iterator to initialise. | |
1285 | * @direction: The direction of the transfer. | |
1286 | * @xarray: The xarray to access. | |
1287 | * @start: The start file position. | |
1288 | * @count: The size of the I/O buffer in bytes. | |
1289 | * | |
1290 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
1291 | * inode or to inject data into those pages. The pages *must* be prevented | |
1292 | * from evaporation, either by taking a ref on them or locking them by the | |
1293 | * caller. | |
1294 | */ | |
1295 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, | |
1296 | struct xarray *xarray, loff_t start, size_t count) | |
1297 | { | |
1298 | BUG_ON(direction & ~1); | |
8cd54c1c AV |
1299 | *i = (struct iov_iter) { |
1300 | .iter_type = ITER_XARRAY, | |
1301 | .data_source = direction, | |
1302 | .xarray = xarray, | |
1303 | .xarray_start = start, | |
1304 | .count = count, | |
1305 | .iov_offset = 0 | |
1306 | }; | |
7ff50620 DH |
1307 | } |
1308 | EXPORT_SYMBOL(iov_iter_xarray); | |
1309 | ||
9ea9ce04 DH |
1310 | /** |
1311 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
1312 | * @i: The iterator to initialise. | |
1313 | * @direction: The direction of the transfer. | |
1314 | * @count: The size of the I/O buffer in bytes. | |
1315 | * | |
1316 | * Set up an I/O iterator that just discards everything that's written to it. | |
1317 | * It's only available as a READ iterator. | |
1318 | */ | |
1319 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
1320 | { | |
1321 | BUG_ON(direction != READ); | |
8cd54c1c AV |
1322 | *i = (struct iov_iter){ |
1323 | .iter_type = ITER_DISCARD, | |
1324 | .data_source = false, | |
1325 | .count = count, | |
1326 | .iov_offset = 0 | |
1327 | }; | |
9ea9ce04 DH |
1328 | } |
1329 | EXPORT_SYMBOL(iov_iter_discard); | |
1330 | ||
9221d2e3 | 1331 | static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) |
62a8067a | 1332 | { |
04a31165 AV |
1333 | unsigned long res = 0; |
1334 | size_t size = i->count; | |
9221d2e3 AV |
1335 | size_t skip = i->iov_offset; |
1336 | unsigned k; | |
1337 | ||
1338 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1339 | size_t len = i->iov[k].iov_len - skip; | |
1340 | if (len) { | |
1341 | res |= (unsigned long)i->iov[k].iov_base + skip; | |
1342 | if (len > size) | |
1343 | len = size; | |
1344 | res |= len; | |
1345 | size -= len; | |
1346 | if (!size) | |
1347 | break; | |
1348 | } | |
1349 | } | |
1350 | return res; | |
1351 | } | |
04a31165 | 1352 | |
9221d2e3 AV |
1353 | static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) |
1354 | { | |
1355 | unsigned res = 0; | |
1356 | size_t size = i->count; | |
1357 | unsigned skip = i->iov_offset; | |
1358 | unsigned k; | |
1359 | ||
1360 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1361 | size_t len = i->bvec[k].bv_len - skip; | |
1362 | res |= (unsigned long)i->bvec[k].bv_offset + skip; | |
1363 | if (len > size) | |
1364 | len = size; | |
1365 | res |= len; | |
1366 | size -= len; | |
1367 | if (!size) | |
1368 | break; | |
1369 | } | |
1370 | return res; | |
1371 | } | |
1372 | ||
1373 | unsigned long iov_iter_alignment(const struct iov_iter *i) | |
1374 | { | |
1375 | /* iovec and kvec have identical layouts */ | |
1376 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1377 | return iov_iter_alignment_iovec(i); | |
1378 | ||
1379 | if (iov_iter_is_bvec(i)) | |
1380 | return iov_iter_alignment_bvec(i); | |
1381 | ||
1382 | if (iov_iter_is_pipe(i)) { | |
e0ff126e | 1383 | unsigned int p_mask = i->pipe->ring_size - 1; |
9221d2e3 | 1384 | size_t size = i->count; |
e0ff126e | 1385 | |
8cefc107 | 1386 | if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) |
241699cd AV |
1387 | return size | i->iov_offset; |
1388 | return size; | |
1389 | } | |
9221d2e3 AV |
1390 | |
1391 | if (iov_iter_is_xarray(i)) | |
3d14ec1f | 1392 | return (i->xarray_start + i->iov_offset) | i->count; |
9221d2e3 AV |
1393 | |
1394 | return 0; | |
62a8067a AV |
1395 | } |
1396 | EXPORT_SYMBOL(iov_iter_alignment); | |
1397 | ||
357f435d AV |
1398 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1399 | { | |
33844e66 | 1400 | unsigned long res = 0; |
610c7a71 | 1401 | unsigned long v = 0; |
357f435d | 1402 | size_t size = i->count; |
610c7a71 | 1403 | unsigned k; |
357f435d | 1404 | |
610c7a71 | 1405 | if (WARN_ON(!iter_is_iovec(i))) |
241699cd | 1406 | return ~0U; |
241699cd | 1407 | |
610c7a71 AV |
1408 | for (k = 0; k < i->nr_segs; k++) { |
1409 | if (i->iov[k].iov_len) { | |
1410 | unsigned long base = (unsigned long)i->iov[k].iov_base; | |
1411 | if (v) // if not the first one | |
1412 | res |= base | v; // this start | previous end | |
1413 | v = base + i->iov[k].iov_len; | |
1414 | if (size <= i->iov[k].iov_len) | |
1415 | break; | |
1416 | size -= i->iov[k].iov_len; | |
1417 | } | |
1418 | } | |
33844e66 | 1419 | return res; |
357f435d AV |
1420 | } |
1421 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1422 | ||
e76b6312 | 1423 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
241699cd AV |
1424 | size_t maxsize, |
1425 | struct page **pages, | |
8cefc107 | 1426 | int iter_head, |
241699cd AV |
1427 | size_t *start) |
1428 | { | |
1429 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1430 | unsigned int p_mask = pipe->ring_size - 1; |
1431 | ssize_t n = push_pipe(i, maxsize, &iter_head, start); | |
241699cd AV |
1432 | if (!n) |
1433 | return -EFAULT; | |
1434 | ||
1435 | maxsize = n; | |
1436 | n += *start; | |
1689c73a | 1437 | while (n > 0) { |
8cefc107 DH |
1438 | get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); |
1439 | iter_head++; | |
241699cd AV |
1440 | n -= PAGE_SIZE; |
1441 | } | |
1442 | ||
1443 | return maxsize; | |
1444 | } | |
1445 | ||
1446 | static ssize_t pipe_get_pages(struct iov_iter *i, | |
1447 | struct page **pages, size_t maxsize, unsigned maxpages, | |
1448 | size_t *start) | |
1449 | { | |
8cefc107 | 1450 | unsigned int iter_head, npages; |
241699cd | 1451 | size_t capacity; |
241699cd AV |
1452 | |
1453 | if (!sanity(i)) | |
1454 | return -EFAULT; | |
1455 | ||
8cefc107 DH |
1456 | data_start(i, &iter_head, start); |
1457 | /* Amount of free space: some of this one + all after this one */ | |
1458 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
1459 | capacity = min(npages, maxpages) * PAGE_SIZE - *start; | |
241699cd | 1460 | |
8cefc107 | 1461 | return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); |
241699cd AV |
1462 | } |
1463 | ||
7ff50620 DH |
1464 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
1465 | pgoff_t index, unsigned int nr_pages) | |
1466 | { | |
1467 | XA_STATE(xas, xa, index); | |
1468 | struct page *page; | |
1469 | unsigned int ret = 0; | |
1470 | ||
1471 | rcu_read_lock(); | |
1472 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1473 | if (xas_retry(&xas, page)) | |
1474 | continue; | |
1475 | ||
1476 | /* Has the page moved or been split? */ | |
1477 | if (unlikely(page != xas_reload(&xas))) { | |
1478 | xas_reset(&xas); | |
1479 | continue; | |
1480 | } | |
1481 | ||
1482 | pages[ret] = find_subpage(page, xas.xa_index); | |
1483 | get_page(pages[ret]); | |
1484 | if (++ret == nr_pages) | |
1485 | break; | |
1486 | } | |
1487 | rcu_read_unlock(); | |
1488 | return ret; | |
1489 | } | |
1490 | ||
1491 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, | |
1492 | struct page **pages, size_t maxsize, | |
1493 | unsigned maxpages, size_t *_start_offset) | |
1494 | { | |
1495 | unsigned nr, offset; | |
1496 | pgoff_t index, count; | |
1497 | size_t size = maxsize, actual; | |
1498 | loff_t pos; | |
1499 | ||
1500 | if (!size || !maxpages) | |
1501 | return 0; | |
1502 | ||
1503 | pos = i->xarray_start + i->iov_offset; | |
1504 | index = pos >> PAGE_SHIFT; | |
1505 | offset = pos & ~PAGE_MASK; | |
1506 | *_start_offset = offset; | |
1507 | ||
1508 | count = 1; | |
1509 | if (size > PAGE_SIZE - offset) { | |
1510 | size -= PAGE_SIZE - offset; | |
1511 | count += size >> PAGE_SHIFT; | |
1512 | size &= ~PAGE_MASK; | |
1513 | if (size) | |
1514 | count++; | |
1515 | } | |
1516 | ||
1517 | if (count > maxpages) | |
1518 | count = maxpages; | |
1519 | ||
1520 | nr = iter_xarray_populate_pages(pages, i->xarray, index, count); | |
1521 | if (nr == 0) | |
1522 | return 0; | |
1523 | ||
1524 | actual = PAGE_SIZE * nr; | |
1525 | actual -= offset; | |
1526 | if (nr == count && size > 0) { | |
1527 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1528 | actual -= PAGE_SIZE - (last_offset + size); | |
1529 | } | |
1530 | return actual; | |
1531 | } | |
1532 | ||
3d671ca6 AV |
1533 | /* must be done on non-empty ITER_IOVEC one */ |
1534 | static unsigned long first_iovec_segment(const struct iov_iter *i, | |
1535 | size_t *size, size_t *start, | |
1536 | size_t maxsize, unsigned maxpages) | |
1537 | { | |
1538 | size_t skip; | |
1539 | long k; | |
1540 | ||
1541 | for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { | |
1542 | unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; | |
1543 | size_t len = i->iov[k].iov_len - skip; | |
1544 | ||
1545 | if (unlikely(!len)) | |
1546 | continue; | |
1547 | if (len > maxsize) | |
1548 | len = maxsize; | |
1549 | len += (*start = addr % PAGE_SIZE); | |
1550 | if (len > maxpages * PAGE_SIZE) | |
1551 | len = maxpages * PAGE_SIZE; | |
1552 | *size = len; | |
1553 | return addr & PAGE_MASK; | |
1554 | } | |
1555 | BUG(); // if it had been empty, we wouldn't get called | |
1556 | } | |
1557 | ||
1558 | /* must be done on non-empty ITER_BVEC one */ | |
1559 | static struct page *first_bvec_segment(const struct iov_iter *i, | |
1560 | size_t *size, size_t *start, | |
1561 | size_t maxsize, unsigned maxpages) | |
1562 | { | |
1563 | struct page *page; | |
1564 | size_t skip = i->iov_offset, len; | |
1565 | ||
1566 | len = i->bvec->bv_len - skip; | |
1567 | if (len > maxsize) | |
1568 | len = maxsize; | |
1569 | skip += i->bvec->bv_offset; | |
1570 | page = i->bvec->bv_page + skip / PAGE_SIZE; | |
1571 | len += (*start = skip % PAGE_SIZE); | |
1572 | if (len > maxpages * PAGE_SIZE) | |
1573 | len = maxpages * PAGE_SIZE; | |
1574 | *size = len; | |
1575 | return page; | |
1576 | } | |
1577 | ||
62a8067a | 1578 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
2c80929c | 1579 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
1580 | size_t *start) |
1581 | { | |
3d671ca6 AV |
1582 | size_t len; |
1583 | int n, res; | |
1584 | ||
e5393fae AV |
1585 | if (maxsize > i->count) |
1586 | maxsize = i->count; | |
3d671ca6 AV |
1587 | if (!maxsize) |
1588 | return 0; | |
e5393fae | 1589 | |
3d671ca6 AV |
1590 | if (likely(iter_is_iovec(i))) { |
1591 | unsigned long addr; | |
e5393fae | 1592 | |
3d671ca6 | 1593 | addr = first_iovec_segment(i, &len, start, maxsize, maxpages); |
e5393fae | 1594 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
73b0140b IW |
1595 | res = get_user_pages_fast(addr, n, |
1596 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, | |
1597 | pages); | |
e5393fae AV |
1598 | if (unlikely(res < 0)) |
1599 | return res; | |
1600 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
3d671ca6 AV |
1601 | } |
1602 | if (iov_iter_is_bvec(i)) { | |
1603 | struct page *page; | |
1604 | ||
1605 | page = first_bvec_segment(i, &len, start, maxsize, maxpages); | |
1606 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1607 | while (n--) | |
1608 | get_page(*pages++ = page++); | |
1609 | return len - *start; | |
1610 | } | |
1611 | if (iov_iter_is_pipe(i)) | |
1612 | return pipe_get_pages(i, pages, maxsize, maxpages, start); | |
1613 | if (iov_iter_is_xarray(i)) | |
1614 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); | |
1615 | return -EFAULT; | |
62a8067a AV |
1616 | } |
1617 | EXPORT_SYMBOL(iov_iter_get_pages); | |
1618 | ||
1b17f1f2 AV |
1619 | static struct page **get_pages_array(size_t n) |
1620 | { | |
752ade68 | 1621 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); |
1b17f1f2 AV |
1622 | } |
1623 | ||
241699cd AV |
1624 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
1625 | struct page ***pages, size_t maxsize, | |
1626 | size_t *start) | |
1627 | { | |
1628 | struct page **p; | |
8cefc107 | 1629 | unsigned int iter_head, npages; |
d7760d63 | 1630 | ssize_t n; |
241699cd AV |
1631 | |
1632 | if (!sanity(i)) | |
1633 | return -EFAULT; | |
1634 | ||
8cefc107 DH |
1635 | data_start(i, &iter_head, start); |
1636 | /* Amount of free space: some of this one + all after this one */ | |
1637 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
241699cd AV |
1638 | n = npages * PAGE_SIZE - *start; |
1639 | if (maxsize > n) | |
1640 | maxsize = n; | |
1641 | else | |
1642 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); | |
1643 | p = get_pages_array(npages); | |
1644 | if (!p) | |
1645 | return -ENOMEM; | |
8cefc107 | 1646 | n = __pipe_get_pages(i, maxsize, p, iter_head, start); |
241699cd AV |
1647 | if (n > 0) |
1648 | *pages = p; | |
1649 | else | |
1650 | kvfree(p); | |
1651 | return n; | |
1652 | } | |
1653 | ||
7ff50620 DH |
1654 | static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, |
1655 | struct page ***pages, size_t maxsize, | |
1656 | size_t *_start_offset) | |
1657 | { | |
1658 | struct page **p; | |
1659 | unsigned nr, offset; | |
1660 | pgoff_t index, count; | |
1661 | size_t size = maxsize, actual; | |
1662 | loff_t pos; | |
1663 | ||
1664 | if (!size) | |
1665 | return 0; | |
1666 | ||
1667 | pos = i->xarray_start + i->iov_offset; | |
1668 | index = pos >> PAGE_SHIFT; | |
1669 | offset = pos & ~PAGE_MASK; | |
1670 | *_start_offset = offset; | |
1671 | ||
1672 | count = 1; | |
1673 | if (size > PAGE_SIZE - offset) { | |
1674 | size -= PAGE_SIZE - offset; | |
1675 | count += size >> PAGE_SHIFT; | |
1676 | size &= ~PAGE_MASK; | |
1677 | if (size) | |
1678 | count++; | |
1679 | } | |
1680 | ||
1681 | p = get_pages_array(count); | |
1682 | if (!p) | |
1683 | return -ENOMEM; | |
1684 | *pages = p; | |
1685 | ||
1686 | nr = iter_xarray_populate_pages(p, i->xarray, index, count); | |
1687 | if (nr == 0) | |
1688 | return 0; | |
1689 | ||
1690 | actual = PAGE_SIZE * nr; | |
1691 | actual -= offset; | |
1692 | if (nr == count && size > 0) { | |
1693 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1694 | actual -= PAGE_SIZE - (last_offset + size); | |
1695 | } | |
1696 | return actual; | |
1697 | } | |
1698 | ||
62a8067a AV |
1699 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
1700 | struct page ***pages, size_t maxsize, | |
1701 | size_t *start) | |
1702 | { | |
1b17f1f2 | 1703 | struct page **p; |
3d671ca6 AV |
1704 | size_t len; |
1705 | int n, res; | |
1b17f1f2 AV |
1706 | |
1707 | if (maxsize > i->count) | |
1708 | maxsize = i->count; | |
3d671ca6 AV |
1709 | if (!maxsize) |
1710 | return 0; | |
1b17f1f2 | 1711 | |
3d671ca6 AV |
1712 | if (likely(iter_is_iovec(i))) { |
1713 | unsigned long addr; | |
1b17f1f2 | 1714 | |
3d671ca6 | 1715 | addr = first_iovec_segment(i, &len, start, maxsize, ~0U); |
1b17f1f2 AV |
1716 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
1717 | p = get_pages_array(n); | |
1718 | if (!p) | |
1719 | return -ENOMEM; | |
73b0140b IW |
1720 | res = get_user_pages_fast(addr, n, |
1721 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); | |
1b17f1f2 AV |
1722 | if (unlikely(res < 0)) { |
1723 | kvfree(p); | |
1724 | return res; | |
1725 | } | |
1726 | *pages = p; | |
1727 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
3d671ca6 AV |
1728 | } |
1729 | if (iov_iter_is_bvec(i)) { | |
1730 | struct page *page; | |
1731 | ||
1732 | page = first_bvec_segment(i, &len, start, maxsize, ~0U); | |
1733 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1734 | *pages = p = get_pages_array(n); | |
1b17f1f2 AV |
1735 | if (!p) |
1736 | return -ENOMEM; | |
3d671ca6 AV |
1737 | while (n--) |
1738 | get_page(*p++ = page++); | |
1739 | return len - *start; | |
1740 | } | |
1741 | if (iov_iter_is_pipe(i)) | |
1742 | return pipe_get_pages_alloc(i, pages, maxsize, start); | |
1743 | if (iov_iter_is_xarray(i)) | |
1744 | return iter_xarray_get_pages_alloc(i, pages, maxsize, start); | |
1745 | return -EFAULT; | |
62a8067a AV |
1746 | } |
1747 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
1748 | ||
a604ec7e AV |
1749 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1750 | struct iov_iter *i) | |
1751 | { | |
1752 | char *to = addr; | |
1753 | __wsum sum, next; | |
1754 | size_t off = 0; | |
a604ec7e | 1755 | sum = *csum; |
9ea9ce04 | 1756 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1757 | WARN_ON(1); |
1758 | return 0; | |
1759 | } | |
a604ec7e | 1760 | iterate_and_advance(i, bytes, v, ({ |
cbbd26b8 | 1761 | next = csum_and_copy_from_user(v.iov_base, |
a604ec7e | 1762 | (to += v.iov_len) - v.iov_len, |
c693cc46 AV |
1763 | v.iov_len); |
1764 | if (next) { | |
a604ec7e AV |
1765 | sum = csum_block_add(sum, next, off); |
1766 | off += v.iov_len; | |
1767 | } | |
c693cc46 | 1768 | next ? 0 : v.iov_len; |
a604ec7e AV |
1769 | }), ({ |
1770 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1771 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
1772 | p + v.bv_offset, v.bv_len, | |
1773 | sum, off); | |
a604ec7e | 1774 | kunmap_atomic(p); |
a604ec7e AV |
1775 | off += v.bv_len; |
1776 | }),({ | |
f9152895 AV |
1777 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
1778 | v.iov_base, v.iov_len, | |
1779 | sum, off); | |
a604ec7e | 1780 | off += v.iov_len; |
7ff50620 DH |
1781 | }), ({ |
1782 | char *p = kmap_atomic(v.bv_page); | |
1783 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, | |
1784 | p + v.bv_offset, v.bv_len, | |
1785 | sum, off); | |
1786 | kunmap_atomic(p); | |
1787 | off += v.bv_len; | |
a604ec7e AV |
1788 | }) |
1789 | ) | |
1790 | *csum = sum; | |
1791 | return bytes; | |
1792 | } | |
1793 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1794 | ||
52cbd23a | 1795 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
a604ec7e AV |
1796 | struct iov_iter *i) |
1797 | { | |
52cbd23a | 1798 | struct csum_state *csstate = _csstate; |
36f7a8a4 | 1799 | const char *from = addr; |
a604ec7e | 1800 | __wsum sum, next; |
52cbd23a | 1801 | size_t off; |
78e1f386 AV |
1802 | |
1803 | if (unlikely(iov_iter_is_pipe(i))) | |
52cbd23a | 1804 | return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); |
78e1f386 | 1805 | |
52cbd23a WB |
1806 | sum = csstate->csum; |
1807 | off = csstate->off; | |
78e1f386 | 1808 | if (unlikely(iov_iter_is_discard(i))) { |
241699cd AV |
1809 | WARN_ON(1); /* for now */ |
1810 | return 0; | |
1811 | } | |
a604ec7e | 1812 | iterate_and_advance(i, bytes, v, ({ |
a604ec7e | 1813 | next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, |
cbbd26b8 | 1814 | v.iov_base, |
c693cc46 AV |
1815 | v.iov_len); |
1816 | if (next) { | |
a604ec7e AV |
1817 | sum = csum_block_add(sum, next, off); |
1818 | off += v.iov_len; | |
1819 | } | |
c693cc46 | 1820 | next ? 0 : v.iov_len; |
a604ec7e AV |
1821 | }), ({ |
1822 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1823 | sum = csum_and_memcpy(p + v.bv_offset, |
1824 | (from += v.bv_len) - v.bv_len, | |
1825 | v.bv_len, sum, off); | |
a604ec7e | 1826 | kunmap_atomic(p); |
a604ec7e AV |
1827 | off += v.bv_len; |
1828 | }),({ | |
f9152895 AV |
1829 | sum = csum_and_memcpy(v.iov_base, |
1830 | (from += v.iov_len) - v.iov_len, | |
1831 | v.iov_len, sum, off); | |
a604ec7e | 1832 | off += v.iov_len; |
7ff50620 DH |
1833 | }), ({ |
1834 | char *p = kmap_atomic(v.bv_page); | |
1835 | sum = csum_and_memcpy(p + v.bv_offset, | |
1836 | (from += v.bv_len) - v.bv_len, | |
1837 | v.bv_len, sum, off); | |
1838 | kunmap_atomic(p); | |
1839 | off += v.bv_len; | |
a604ec7e AV |
1840 | }) |
1841 | ) | |
52cbd23a WB |
1842 | csstate->csum = sum; |
1843 | csstate->off = off; | |
a604ec7e AV |
1844 | return bytes; |
1845 | } | |
1846 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1847 | ||
d05f4435 SG |
1848 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
1849 | struct iov_iter *i) | |
1850 | { | |
7999096f | 1851 | #ifdef CONFIG_CRYPTO_HASH |
d05f4435 SG |
1852 | struct ahash_request *hash = hashp; |
1853 | struct scatterlist sg; | |
1854 | size_t copied; | |
1855 | ||
1856 | copied = copy_to_iter(addr, bytes, i); | |
1857 | sg_init_one(&sg, addr, copied); | |
1858 | ahash_request_set_crypt(hash, &sg, NULL, copied); | |
1859 | crypto_ahash_update(hash); | |
1860 | return copied; | |
27fad74a Y |
1861 | #else |
1862 | return 0; | |
1863 | #endif | |
d05f4435 SG |
1864 | } |
1865 | EXPORT_SYMBOL(hash_and_copy_to_iter); | |
1866 | ||
66531c65 | 1867 | static int iov_npages(const struct iov_iter *i, int maxpages) |
62a8067a | 1868 | { |
66531c65 AV |
1869 | size_t skip = i->iov_offset, size = i->count; |
1870 | const struct iovec *p; | |
e0f2dc40 AV |
1871 | int npages = 0; |
1872 | ||
66531c65 AV |
1873 | for (p = i->iov; size; skip = 0, p++) { |
1874 | unsigned offs = offset_in_page(p->iov_base + skip); | |
1875 | size_t len = min(p->iov_len - skip, size); | |
e0f2dc40 | 1876 | |
66531c65 AV |
1877 | if (len) { |
1878 | size -= len; | |
1879 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1880 | if (unlikely(npages > maxpages)) | |
1881 | return maxpages; | |
1882 | } | |
1883 | } | |
1884 | return npages; | |
1885 | } | |
1886 | ||
1887 | static int bvec_npages(const struct iov_iter *i, int maxpages) | |
1888 | { | |
1889 | size_t skip = i->iov_offset, size = i->count; | |
1890 | const struct bio_vec *p; | |
1891 | int npages = 0; | |
1892 | ||
1893 | for (p = i->bvec; size; skip = 0, p++) { | |
1894 | unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; | |
1895 | size_t len = min(p->bv_len - skip, size); | |
1896 | ||
1897 | size -= len; | |
1898 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1899 | if (unlikely(npages > maxpages)) | |
1900 | return maxpages; | |
1901 | } | |
1902 | return npages; | |
1903 | } | |
1904 | ||
1905 | int iov_iter_npages(const struct iov_iter *i, int maxpages) | |
1906 | { | |
1907 | if (unlikely(!i->count)) | |
1908 | return 0; | |
1909 | /* iovec and kvec have identical layouts */ | |
1910 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1911 | return iov_npages(i, maxpages); | |
1912 | if (iov_iter_is_bvec(i)) | |
1913 | return bvec_npages(i, maxpages); | |
1914 | if (iov_iter_is_pipe(i)) { | |
8cefc107 | 1915 | unsigned int iter_head; |
66531c65 | 1916 | int npages; |
241699cd | 1917 | size_t off; |
241699cd AV |
1918 | |
1919 | if (!sanity(i)) | |
1920 | return 0; | |
1921 | ||
8cefc107 | 1922 | data_start(i, &iter_head, &off); |
241699cd | 1923 | /* some of this one + all after this one */ |
66531c65 AV |
1924 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); |
1925 | return min(npages, maxpages); | |
1926 | } | |
1927 | if (iov_iter_is_xarray(i)) { | |
1928 | size_t size = i->count; | |
7ff50620 | 1929 | unsigned offset; |
66531c65 | 1930 | int npages; |
7ff50620 DH |
1931 | |
1932 | offset = (i->xarray_start + i->iov_offset) & ~PAGE_MASK; | |
1933 | ||
1934 | npages = 1; | |
1935 | if (size > PAGE_SIZE - offset) { | |
1936 | size -= PAGE_SIZE - offset; | |
1937 | npages += size >> PAGE_SHIFT; | |
1938 | size &= ~PAGE_MASK; | |
1939 | if (size) | |
1940 | npages++; | |
1941 | } | |
66531c65 AV |
1942 | return min(npages, maxpages); |
1943 | } | |
1944 | return 0; | |
62a8067a | 1945 | } |
f67da30c | 1946 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1947 | |
1948 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1949 | { | |
1950 | *new = *old; | |
00e23707 | 1951 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1952 | WARN_ON(1); |
1953 | return NULL; | |
1954 | } | |
7ff50620 | 1955 | if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) |
9ea9ce04 | 1956 | return NULL; |
00e23707 | 1957 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1958 | return new->bvec = kmemdup(new->bvec, |
1959 | new->nr_segs * sizeof(struct bio_vec), | |
1960 | flags); | |
1961 | else | |
1962 | /* iovec and kvec have identical layout */ | |
1963 | return new->iov = kmemdup(new->iov, | |
1964 | new->nr_segs * sizeof(struct iovec), | |
1965 | flags); | |
1966 | } | |
1967 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1968 | |
bfdc5970 CH |
1969 | static int copy_compat_iovec_from_user(struct iovec *iov, |
1970 | const struct iovec __user *uvec, unsigned long nr_segs) | |
1971 | { | |
1972 | const struct compat_iovec __user *uiov = | |
1973 | (const struct compat_iovec __user *)uvec; | |
1974 | int ret = -EFAULT, i; | |
1975 | ||
a959a978 | 1976 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
1977 | return -EFAULT; |
1978 | ||
1979 | for (i = 0; i < nr_segs; i++) { | |
1980 | compat_uptr_t buf; | |
1981 | compat_ssize_t len; | |
1982 | ||
1983 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); | |
1984 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); | |
1985 | ||
1986 | /* check for compat_size_t not fitting in compat_ssize_t .. */ | |
1987 | if (len < 0) { | |
1988 | ret = -EINVAL; | |
1989 | goto uaccess_end; | |
1990 | } | |
1991 | iov[i].iov_base = compat_ptr(buf); | |
1992 | iov[i].iov_len = len; | |
1993 | } | |
1994 | ||
1995 | ret = 0; | |
1996 | uaccess_end: | |
1997 | user_access_end(); | |
1998 | return ret; | |
1999 | } | |
2000 | ||
2001 | static int copy_iovec_from_user(struct iovec *iov, | |
2002 | const struct iovec __user *uvec, unsigned long nr_segs) | |
fb041b59 DL |
2003 | { |
2004 | unsigned long seg; | |
fb041b59 | 2005 | |
bfdc5970 CH |
2006 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
2007 | return -EFAULT; | |
2008 | for (seg = 0; seg < nr_segs; seg++) { | |
2009 | if ((ssize_t)iov[seg].iov_len < 0) | |
2010 | return -EINVAL; | |
fb041b59 DL |
2011 | } |
2012 | ||
bfdc5970 CH |
2013 | return 0; |
2014 | } | |
2015 | ||
2016 | struct iovec *iovec_from_user(const struct iovec __user *uvec, | |
2017 | unsigned long nr_segs, unsigned long fast_segs, | |
2018 | struct iovec *fast_iov, bool compat) | |
2019 | { | |
2020 | struct iovec *iov = fast_iov; | |
2021 | int ret; | |
2022 | ||
fb041b59 | 2023 | /* |
bfdc5970 CH |
2024 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
2025 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
2026 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 2027 | */ |
bfdc5970 CH |
2028 | if (nr_segs == 0) |
2029 | return iov; | |
2030 | if (nr_segs > UIO_MAXIOV) | |
2031 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
2032 | if (nr_segs > fast_segs) { |
2033 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
2034 | if (!iov) |
2035 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 2036 | } |
bfdc5970 CH |
2037 | |
2038 | if (compat) | |
2039 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); | |
2040 | else | |
2041 | ret = copy_iovec_from_user(iov, uvec, nr_segs); | |
2042 | if (ret) { | |
2043 | if (iov != fast_iov) | |
2044 | kfree(iov); | |
2045 | return ERR_PTR(ret); | |
2046 | } | |
2047 | ||
2048 | return iov; | |
2049 | } | |
2050 | ||
2051 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
2052 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
2053 | struct iov_iter *i, bool compat) | |
2054 | { | |
2055 | ssize_t total_len = 0; | |
2056 | unsigned long seg; | |
2057 | struct iovec *iov; | |
2058 | ||
2059 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); | |
2060 | if (IS_ERR(iov)) { | |
2061 | *iovp = NULL; | |
2062 | return PTR_ERR(iov); | |
fb041b59 DL |
2063 | } |
2064 | ||
2065 | /* | |
bfdc5970 CH |
2066 | * According to the Single Unix Specification we should return EINVAL if |
2067 | * an element length is < 0 when cast to ssize_t or if the total length | |
2068 | * would overflow the ssize_t return value of the system call. | |
fb041b59 DL |
2069 | * |
2070 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
2071 | * overflow case. | |
2072 | */ | |
fb041b59 | 2073 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
2074 | ssize_t len = (ssize_t)iov[seg].iov_len; |
2075 | ||
bfdc5970 CH |
2076 | if (!access_ok(iov[seg].iov_base, len)) { |
2077 | if (iov != *iovp) | |
2078 | kfree(iov); | |
2079 | *iovp = NULL; | |
2080 | return -EFAULT; | |
fb041b59 | 2081 | } |
bfdc5970 CH |
2082 | |
2083 | if (len > MAX_RW_COUNT - total_len) { | |
2084 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
2085 | iov[seg].iov_len = len; |
2086 | } | |
bfdc5970 | 2087 | total_len += len; |
fb041b59 | 2088 | } |
bfdc5970 CH |
2089 | |
2090 | iov_iter_init(i, type, iov, nr_segs, total_len); | |
2091 | if (iov == *iovp) | |
2092 | *iovp = NULL; | |
2093 | else | |
2094 | *iovp = iov; | |
2095 | return total_len; | |
fb041b59 DL |
2096 | } |
2097 | ||
ffecee4f VN |
2098 | /** |
2099 | * import_iovec() - Copy an array of &struct iovec from userspace | |
2100 | * into the kernel, check that it is valid, and initialize a new | |
2101 | * &struct iov_iter iterator to access it. | |
2102 | * | |
2103 | * @type: One of %READ or %WRITE. | |
bfdc5970 | 2104 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
2105 | * @nr_segs: Number of elements in userspace array. |
2106 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 2107 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
2108 | * on-stack) kernel array. |
2109 | * @i: Pointer to iterator that will be initialized on success. | |
2110 | * | |
2111 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
2112 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
2113 | * array will be allocated and the result placed in *@iov. This means that | |
2114 | * the caller may call kfree() on *@iov regardless of whether the small | |
2115 | * on-stack array was used or not (and regardless of whether this function | |
2116 | * returns an error or not). | |
2117 | * | |
87e5e6da | 2118 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 2119 | */ |
bfdc5970 | 2120 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 2121 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 2122 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 2123 | { |
89cd35c5 CH |
2124 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
2125 | in_compat_syscall()); | |
bc917be8 AV |
2126 | } |
2127 | EXPORT_SYMBOL(import_iovec); | |
2128 | ||
bc917be8 AV |
2129 | int import_single_range(int rw, void __user *buf, size_t len, |
2130 | struct iovec *iov, struct iov_iter *i) | |
2131 | { | |
2132 | if (len > MAX_RW_COUNT) | |
2133 | len = MAX_RW_COUNT; | |
96d4f267 | 2134 | if (unlikely(!access_ok(buf, len))) |
bc917be8 AV |
2135 | return -EFAULT; |
2136 | ||
2137 | iov->iov_base = buf; | |
2138 | iov->iov_len = len; | |
2139 | iov_iter_init(i, rw, iov, 1, len); | |
2140 | return 0; | |
2141 | } | |
e1267585 | 2142 | EXPORT_SYMBOL(import_single_range); |