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 | ||
5c67aa90 | 19 | /* covers iovec and kvec alike */ |
7a1bcb5d AV |
20 | #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ |
21 | size_t left; \ | |
22 | size_t wanted = n; \ | |
7a1bcb5d AV |
23 | do { \ |
24 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
25 | if (likely(__v.iov_len)) { \ | |
26 | __v.iov_base = __p->iov_base + skip; \ | |
27 | left = (STEP); \ | |
28 | __v.iov_len -= left; \ | |
29 | skip += __v.iov_len; \ | |
30 | n -= __v.iov_len; \ | |
31 | if (skip < __p->iov_len) \ | |
32 | break; \ | |
33 | } \ | |
34 | __p++; \ | |
35 | skip = 0; \ | |
36 | } while (n); \ | |
37 | n = wanted - n; \ | |
04a31165 AV |
38 | } |
39 | ||
7491a2bf AV |
40 | #define iterate_bvec(i, n, __v, p, skip, STEP) { \ |
41 | size_t wanted = n; \ | |
42 | while (n) { \ | |
43 | unsigned offset = p->bv_offset + skip; \ | |
1b4fb5ff | 44 | unsigned left; \ |
21b56c84 AV |
45 | void *kaddr = kmap_local_page(p->bv_page + \ |
46 | offset / PAGE_SIZE); \ | |
47 | __v.iov_base = kaddr + offset % PAGE_SIZE; \ | |
48 | __v.iov_len = min(min(n, p->bv_len - skip), \ | |
7491a2bf | 49 | (size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ |
1b4fb5ff | 50 | left = (STEP); \ |
21b56c84 AV |
51 | kunmap_local(kaddr); \ |
52 | __v.iov_len -= left; \ | |
53 | skip += __v.iov_len; \ | |
7491a2bf AV |
54 | if (skip == p->bv_len) { \ |
55 | skip = 0; \ | |
56 | p++; \ | |
57 | } \ | |
21b56c84 | 58 | n -= __v.iov_len; \ |
1b4fb5ff AV |
59 | if (left) \ |
60 | break; \ | |
7491a2bf AV |
61 | } \ |
62 | n = wanted - n; \ | |
04a31165 AV |
63 | } |
64 | ||
7ff50620 | 65 | #define iterate_xarray(i, n, __v, skip, STEP) { \ |
1b4fb5ff | 66 | __label__ __out; \ |
7ff50620 DH |
67 | struct page *head = NULL; \ |
68 | size_t wanted = n, seg, offset; \ | |
69 | loff_t start = i->xarray_start + skip; \ | |
70 | pgoff_t index = start >> PAGE_SHIFT; \ | |
71 | int j; \ | |
72 | \ | |
73 | XA_STATE(xas, i->xarray, index); \ | |
74 | \ | |
75 | rcu_read_lock(); \ | |
76 | xas_for_each(&xas, head, ULONG_MAX) { \ | |
1b4fb5ff | 77 | unsigned left; \ |
7ff50620 DH |
78 | if (xas_retry(&xas, head)) \ |
79 | continue; \ | |
80 | if (WARN_ON(xa_is_value(head))) \ | |
81 | break; \ | |
82 | if (WARN_ON(PageHuge(head))) \ | |
83 | break; \ | |
84 | for (j = (head->index < index) ? index - head->index : 0; \ | |
85 | j < thp_nr_pages(head); j++) { \ | |
21b56c84 AV |
86 | void *kaddr = kmap_local_page(head + j); \ |
87 | offset = (i->xarray_start + skip) % PAGE_SIZE; \ | |
88 | __v.iov_base = kaddr + offset; \ | |
7ff50620 | 89 | seg = PAGE_SIZE - offset; \ |
21b56c84 | 90 | __v.iov_len = min(n, seg); \ |
1b4fb5ff | 91 | left = (STEP); \ |
21b56c84 AV |
92 | kunmap_local(kaddr); \ |
93 | __v.iov_len -= left; \ | |
94 | n -= __v.iov_len; \ | |
95 | skip += __v.iov_len; \ | |
1b4fb5ff AV |
96 | if (left || n == 0) \ |
97 | goto __out; \ | |
7ff50620 | 98 | } \ |
7ff50620 | 99 | } \ |
1b4fb5ff | 100 | __out: \ |
7ff50620 DH |
101 | rcu_read_unlock(); \ |
102 | n = wanted - n; \ | |
103 | } | |
104 | ||
21b56c84 | 105 | #define __iterate_and_advance(i, n, v, I, K) { \ |
dd254f5a AV |
106 | if (unlikely(i->count < n)) \ |
107 | n = i->count; \ | |
f5da8354 | 108 | if (likely(n)) { \ |
dd254f5a | 109 | size_t skip = i->iov_offset; \ |
28f38db7 | 110 | if (likely(iter_is_iovec(i))) { \ |
5c67aa90 | 111 | const struct iovec *iov = i->iov; \ |
28f38db7 AV |
112 | struct iovec v; \ |
113 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
28f38db7 AV |
114 | i->nr_segs -= iov - i->iov; \ |
115 | i->iov = iov; \ | |
116 | } else if (iov_iter_is_bvec(i)) { \ | |
1bdc76ae | 117 | const struct bio_vec *bvec = i->bvec; \ |
21b56c84 AV |
118 | struct kvec v; \ |
119 | iterate_bvec(i, n, v, bvec, skip, (K)) \ | |
7491a2bf AV |
120 | i->nr_segs -= bvec - i->bvec; \ |
121 | i->bvec = bvec; \ | |
28f38db7 | 122 | } else if (iov_iter_is_kvec(i)) { \ |
5c67aa90 | 123 | const struct kvec *kvec = i->kvec; \ |
dd254f5a | 124 | struct kvec v; \ |
1b4fb5ff | 125 | iterate_iovec(i, n, v, kvec, skip, (K)) \ |
dd254f5a AV |
126 | i->nr_segs -= kvec - i->kvec; \ |
127 | i->kvec = kvec; \ | |
28f38db7 | 128 | } else if (iov_iter_is_xarray(i)) { \ |
21b56c84 AV |
129 | struct kvec v; \ |
130 | iterate_xarray(i, n, v, skip, (K)) \ | |
7ce2a91e | 131 | } \ |
dd254f5a AV |
132 | i->count -= n; \ |
133 | i->iov_offset = skip; \ | |
7ce2a91e | 134 | } \ |
7ce2a91e | 135 | } |
21b56c84 AV |
136 | #define iterate_and_advance(i, n, v, I, K) \ |
137 | __iterate_and_advance(i, n, v, I, ((void)(K),0)) | |
7ce2a91e | 138 | |
09fc68dc AV |
139 | static int copyout(void __user *to, const void *from, size_t n) |
140 | { | |
4d0e9df5 AL |
141 | if (should_fail_usercopy()) |
142 | return n; | |
96d4f267 | 143 | if (access_ok(to, n)) { |
d0ef4c36 | 144 | instrument_copy_to_user(to, from, n); |
09fc68dc AV |
145 | n = raw_copy_to_user(to, from, n); |
146 | } | |
147 | return n; | |
148 | } | |
149 | ||
150 | static int copyin(void *to, const void __user *from, size_t n) | |
151 | { | |
4d0e9df5 AL |
152 | if (should_fail_usercopy()) |
153 | return n; | |
96d4f267 | 154 | if (access_ok(from, n)) { |
d0ef4c36 | 155 | instrument_copy_from_user(to, from, n); |
09fc68dc AV |
156 | n = raw_copy_from_user(to, from, n); |
157 | } | |
158 | return n; | |
159 | } | |
160 | ||
62a8067a | 161 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
162 | struct iov_iter *i) |
163 | { | |
164 | size_t skip, copy, left, wanted; | |
165 | const struct iovec *iov; | |
166 | char __user *buf; | |
167 | void *kaddr, *from; | |
168 | ||
169 | if (unlikely(bytes > i->count)) | |
170 | bytes = i->count; | |
171 | ||
172 | if (unlikely(!bytes)) | |
173 | return 0; | |
174 | ||
09fc68dc | 175 | might_fault(); |
4f18cd31 AV |
176 | wanted = bytes; |
177 | iov = i->iov; | |
178 | skip = i->iov_offset; | |
179 | buf = iov->iov_base + skip; | |
180 | copy = min(bytes, iov->iov_len - skip); | |
181 | ||
3fa6c507 | 182 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { |
4f18cd31 AV |
183 | kaddr = kmap_atomic(page); |
184 | from = kaddr + offset; | |
185 | ||
186 | /* first chunk, usually the only one */ | |
09fc68dc | 187 | left = copyout(buf, from, copy); |
4f18cd31 AV |
188 | copy -= left; |
189 | skip += copy; | |
190 | from += copy; | |
191 | bytes -= copy; | |
192 | ||
193 | while (unlikely(!left && bytes)) { | |
194 | iov++; | |
195 | buf = iov->iov_base; | |
196 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 197 | left = copyout(buf, from, copy); |
4f18cd31 AV |
198 | copy -= left; |
199 | skip = copy; | |
200 | from += copy; | |
201 | bytes -= copy; | |
202 | } | |
203 | if (likely(!bytes)) { | |
204 | kunmap_atomic(kaddr); | |
205 | goto done; | |
206 | } | |
207 | offset = from - kaddr; | |
208 | buf += copy; | |
209 | kunmap_atomic(kaddr); | |
210 | copy = min(bytes, iov->iov_len - skip); | |
211 | } | |
212 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 213 | |
4f18cd31 AV |
214 | kaddr = kmap(page); |
215 | from = kaddr + offset; | |
09fc68dc | 216 | left = copyout(buf, from, copy); |
4f18cd31 AV |
217 | copy -= left; |
218 | skip += copy; | |
219 | from += copy; | |
220 | bytes -= copy; | |
221 | while (unlikely(!left && bytes)) { | |
222 | iov++; | |
223 | buf = iov->iov_base; | |
224 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 225 | left = copyout(buf, from, copy); |
4f18cd31 AV |
226 | copy -= left; |
227 | skip = copy; | |
228 | from += copy; | |
229 | bytes -= copy; | |
230 | } | |
231 | kunmap(page); | |
3fa6c507 | 232 | |
4f18cd31 | 233 | done: |
81055e58 AV |
234 | if (skip == iov->iov_len) { |
235 | iov++; | |
236 | skip = 0; | |
237 | } | |
4f18cd31 AV |
238 | i->count -= wanted - bytes; |
239 | i->nr_segs -= iov - i->iov; | |
240 | i->iov = iov; | |
241 | i->iov_offset = skip; | |
242 | return wanted - bytes; | |
243 | } | |
4f18cd31 | 244 | |
62a8067a | 245 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
246 | struct iov_iter *i) |
247 | { | |
248 | size_t skip, copy, left, wanted; | |
249 | const struct iovec *iov; | |
250 | char __user *buf; | |
251 | void *kaddr, *to; | |
252 | ||
253 | if (unlikely(bytes > i->count)) | |
254 | bytes = i->count; | |
255 | ||
256 | if (unlikely(!bytes)) | |
257 | return 0; | |
258 | ||
09fc68dc | 259 | might_fault(); |
f0d1bec9 AV |
260 | wanted = bytes; |
261 | iov = i->iov; | |
262 | skip = i->iov_offset; | |
263 | buf = iov->iov_base + skip; | |
264 | copy = min(bytes, iov->iov_len - skip); | |
265 | ||
3fa6c507 | 266 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { |
f0d1bec9 AV |
267 | kaddr = kmap_atomic(page); |
268 | to = kaddr + offset; | |
269 | ||
270 | /* first chunk, usually the only one */ | |
09fc68dc | 271 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
272 | copy -= left; |
273 | skip += copy; | |
274 | to += copy; | |
275 | bytes -= copy; | |
276 | ||
277 | while (unlikely(!left && bytes)) { | |
278 | iov++; | |
279 | buf = iov->iov_base; | |
280 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 281 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
282 | copy -= left; |
283 | skip = copy; | |
284 | to += copy; | |
285 | bytes -= copy; | |
286 | } | |
287 | if (likely(!bytes)) { | |
288 | kunmap_atomic(kaddr); | |
289 | goto done; | |
290 | } | |
291 | offset = to - kaddr; | |
292 | buf += copy; | |
293 | kunmap_atomic(kaddr); | |
294 | copy = min(bytes, iov->iov_len - skip); | |
295 | } | |
296 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 297 | |
f0d1bec9 AV |
298 | kaddr = kmap(page); |
299 | to = kaddr + offset; | |
09fc68dc | 300 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
301 | copy -= left; |
302 | skip += copy; | |
303 | to += copy; | |
304 | bytes -= copy; | |
305 | while (unlikely(!left && bytes)) { | |
306 | iov++; | |
307 | buf = iov->iov_base; | |
308 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 309 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
310 | copy -= left; |
311 | skip = copy; | |
312 | to += copy; | |
313 | bytes -= copy; | |
314 | } | |
315 | kunmap(page); | |
3fa6c507 | 316 | |
f0d1bec9 | 317 | done: |
81055e58 AV |
318 | if (skip == iov->iov_len) { |
319 | iov++; | |
320 | skip = 0; | |
321 | } | |
f0d1bec9 AV |
322 | i->count -= wanted - bytes; |
323 | i->nr_segs -= iov - i->iov; | |
324 | i->iov = iov; | |
325 | i->iov_offset = skip; | |
326 | return wanted - bytes; | |
327 | } | |
f0d1bec9 | 328 | |
241699cd AV |
329 | #ifdef PIPE_PARANOIA |
330 | static bool sanity(const struct iov_iter *i) | |
331 | { | |
332 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
333 | unsigned int p_head = pipe->head; |
334 | unsigned int p_tail = pipe->tail; | |
335 | unsigned int p_mask = pipe->ring_size - 1; | |
336 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); | |
337 | unsigned int i_head = i->head; | |
338 | unsigned int idx; | |
339 | ||
241699cd AV |
340 | if (i->iov_offset) { |
341 | struct pipe_buffer *p; | |
8cefc107 | 342 | if (unlikely(p_occupancy == 0)) |
241699cd | 343 | goto Bad; // pipe must be non-empty |
8cefc107 | 344 | if (unlikely(i_head != p_head - 1)) |
241699cd AV |
345 | goto Bad; // must be at the last buffer... |
346 | ||
8cefc107 | 347 | p = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
348 | if (unlikely(p->offset + p->len != i->iov_offset)) |
349 | goto Bad; // ... at the end of segment | |
350 | } else { | |
8cefc107 | 351 | if (i_head != p_head) |
241699cd AV |
352 | goto Bad; // must be right after the last buffer |
353 | } | |
354 | return true; | |
355 | Bad: | |
8cefc107 DH |
356 | printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); |
357 | printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", | |
358 | p_head, p_tail, pipe->ring_size); | |
359 | for (idx = 0; idx < pipe->ring_size; idx++) | |
241699cd AV |
360 | printk(KERN_ERR "[%p %p %d %d]\n", |
361 | pipe->bufs[idx].ops, | |
362 | pipe->bufs[idx].page, | |
363 | pipe->bufs[idx].offset, | |
364 | pipe->bufs[idx].len); | |
365 | WARN_ON(1); | |
366 | return false; | |
367 | } | |
368 | #else | |
369 | #define sanity(i) true | |
370 | #endif | |
371 | ||
241699cd AV |
372 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
373 | struct iov_iter *i) | |
374 | { | |
375 | struct pipe_inode_info *pipe = i->pipe; | |
376 | struct pipe_buffer *buf; | |
8cefc107 DH |
377 | unsigned int p_tail = pipe->tail; |
378 | unsigned int p_mask = pipe->ring_size - 1; | |
379 | unsigned int i_head = i->head; | |
241699cd | 380 | size_t off; |
241699cd AV |
381 | |
382 | if (unlikely(bytes > i->count)) | |
383 | bytes = i->count; | |
384 | ||
385 | if (unlikely(!bytes)) | |
386 | return 0; | |
387 | ||
388 | if (!sanity(i)) | |
389 | return 0; | |
390 | ||
391 | off = i->iov_offset; | |
8cefc107 | 392 | buf = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
393 | if (off) { |
394 | if (offset == off && buf->page == page) { | |
395 | /* merge with the last one */ | |
396 | buf->len += bytes; | |
397 | i->iov_offset += bytes; | |
398 | goto out; | |
399 | } | |
8cefc107 DH |
400 | i_head++; |
401 | buf = &pipe->bufs[i_head & p_mask]; | |
241699cd | 402 | } |
6718b6f8 | 403 | if (pipe_full(i_head, p_tail, pipe->max_usage)) |
241699cd | 404 | return 0; |
8cefc107 | 405 | |
241699cd | 406 | buf->ops = &page_cache_pipe_buf_ops; |
8cefc107 DH |
407 | get_page(page); |
408 | buf->page = page; | |
241699cd AV |
409 | buf->offset = offset; |
410 | buf->len = bytes; | |
8cefc107 DH |
411 | |
412 | pipe->head = i_head + 1; | |
241699cd | 413 | i->iov_offset = offset + bytes; |
8cefc107 | 414 | i->head = i_head; |
241699cd AV |
415 | out: |
416 | i->count -= bytes; | |
417 | return bytes; | |
418 | } | |
419 | ||
171a0203 AA |
420 | /* |
421 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of | |
422 | * bytes. For each iovec, fault in each page that constitutes the iovec. | |
423 | * | |
424 | * Return 0 on success, or non-zero if the memory could not be accessed (i.e. | |
425 | * because it is an invalid address). | |
426 | */ | |
8409a0d2 | 427 | int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) |
171a0203 | 428 | { |
0e8f0d67 | 429 | if (iter_is_iovec(i)) { |
8409a0d2 AV |
430 | const struct iovec *p; |
431 | size_t skip; | |
432 | ||
433 | if (bytes > i->count) | |
434 | bytes = i->count; | |
435 | for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { | |
436 | size_t len = min(bytes, p->iov_len - skip); | |
437 | int err; | |
438 | ||
439 | if (unlikely(!len)) | |
440 | continue; | |
441 | err = fault_in_pages_readable(p->iov_base + skip, len); | |
171a0203 | 442 | if (unlikely(err)) |
8409a0d2 AV |
443 | return err; |
444 | bytes -= len; | |
445 | } | |
171a0203 AA |
446 | } |
447 | return 0; | |
448 | } | |
d4690f1e | 449 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
171a0203 | 450 | |
aa563d7b | 451 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
452 | const struct iovec *iov, unsigned long nr_segs, |
453 | size_t count) | |
454 | { | |
aa563d7b | 455 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
456 | WARN_ON_ONCE(uaccess_kernel()); |
457 | *i = (struct iov_iter) { | |
458 | .iter_type = ITER_IOVEC, | |
459 | .data_source = direction, | |
460 | .iov = iov, | |
461 | .nr_segs = nr_segs, | |
462 | .iov_offset = 0, | |
463 | .count = count | |
464 | }; | |
71d8e532 AV |
465 | } |
466 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 467 | |
241699cd AV |
468 | static inline bool allocated(struct pipe_buffer *buf) |
469 | { | |
470 | return buf->ops == &default_pipe_buf_ops; | |
471 | } | |
472 | ||
8cefc107 DH |
473 | static inline void data_start(const struct iov_iter *i, |
474 | unsigned int *iter_headp, size_t *offp) | |
241699cd | 475 | { |
8cefc107 DH |
476 | unsigned int p_mask = i->pipe->ring_size - 1; |
477 | unsigned int iter_head = i->head; | |
241699cd | 478 | size_t off = i->iov_offset; |
8cefc107 DH |
479 | |
480 | if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || | |
481 | off == PAGE_SIZE)) { | |
482 | iter_head++; | |
241699cd AV |
483 | off = 0; |
484 | } | |
8cefc107 | 485 | *iter_headp = iter_head; |
241699cd AV |
486 | *offp = off; |
487 | } | |
488 | ||
489 | static size_t push_pipe(struct iov_iter *i, size_t size, | |
8cefc107 | 490 | int *iter_headp, size_t *offp) |
241699cd AV |
491 | { |
492 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
493 | unsigned int p_tail = pipe->tail; |
494 | unsigned int p_mask = pipe->ring_size - 1; | |
495 | unsigned int iter_head; | |
241699cd | 496 | size_t off; |
241699cd AV |
497 | ssize_t left; |
498 | ||
499 | if (unlikely(size > i->count)) | |
500 | size = i->count; | |
501 | if (unlikely(!size)) | |
502 | return 0; | |
503 | ||
504 | left = size; | |
8cefc107 DH |
505 | data_start(i, &iter_head, &off); |
506 | *iter_headp = iter_head; | |
241699cd AV |
507 | *offp = off; |
508 | if (off) { | |
509 | left -= PAGE_SIZE - off; | |
510 | if (left <= 0) { | |
8cefc107 | 511 | pipe->bufs[iter_head & p_mask].len += size; |
241699cd AV |
512 | return size; |
513 | } | |
8cefc107 DH |
514 | pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; |
515 | iter_head++; | |
241699cd | 516 | } |
6718b6f8 | 517 | while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { |
8cefc107 | 518 | struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; |
241699cd AV |
519 | struct page *page = alloc_page(GFP_USER); |
520 | if (!page) | |
521 | break; | |
8cefc107 DH |
522 | |
523 | buf->ops = &default_pipe_buf_ops; | |
524 | buf->page = page; | |
525 | buf->offset = 0; | |
526 | buf->len = min_t(ssize_t, left, PAGE_SIZE); | |
527 | left -= buf->len; | |
528 | iter_head++; | |
529 | pipe->head = iter_head; | |
530 | ||
531 | if (left == 0) | |
241699cd | 532 | return size; |
241699cd AV |
533 | } |
534 | return size - left; | |
535 | } | |
536 | ||
537 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, | |
538 | struct iov_iter *i) | |
539 | { | |
540 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
541 | unsigned int p_mask = pipe->ring_size - 1; |
542 | unsigned int i_head; | |
241699cd | 543 | size_t n, off; |
241699cd AV |
544 | |
545 | if (!sanity(i)) | |
546 | return 0; | |
547 | ||
8cefc107 | 548 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
549 | if (unlikely(!n)) |
550 | return 0; | |
8cefc107 | 551 | do { |
241699cd | 552 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
553 | memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); |
554 | i->head = i_head; | |
241699cd AV |
555 | i->iov_offset = off + chunk; |
556 | n -= chunk; | |
557 | addr += chunk; | |
8cefc107 DH |
558 | off = 0; |
559 | i_head++; | |
560 | } while (n); | |
241699cd AV |
561 | i->count -= bytes; |
562 | return bytes; | |
563 | } | |
564 | ||
f9152895 AV |
565 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
566 | __wsum sum, size_t off) | |
567 | { | |
cc44c17b | 568 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
f9152895 AV |
569 | return csum_block_add(sum, next, off); |
570 | } | |
571 | ||
78e1f386 | 572 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
52cbd23a WB |
573 | struct csum_state *csstate, |
574 | struct iov_iter *i) | |
78e1f386 AV |
575 | { |
576 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 | 577 | unsigned int p_mask = pipe->ring_size - 1; |
52cbd23a WB |
578 | __wsum sum = csstate->csum; |
579 | size_t off = csstate->off; | |
8cefc107 | 580 | unsigned int i_head; |
78e1f386 | 581 | size_t n, r; |
78e1f386 AV |
582 | |
583 | if (!sanity(i)) | |
584 | return 0; | |
585 | ||
8cefc107 | 586 | bytes = n = push_pipe(i, bytes, &i_head, &r); |
78e1f386 AV |
587 | if (unlikely(!n)) |
588 | return 0; | |
8cefc107 | 589 | do { |
78e1f386 | 590 | size_t chunk = min_t(size_t, n, PAGE_SIZE - r); |
8cefc107 | 591 | char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); |
f9152895 | 592 | sum = csum_and_memcpy(p + r, addr, chunk, sum, off); |
78e1f386 | 593 | kunmap_atomic(p); |
8cefc107 | 594 | i->head = i_head; |
78e1f386 AV |
595 | i->iov_offset = r + chunk; |
596 | n -= chunk; | |
597 | off += chunk; | |
598 | addr += chunk; | |
8cefc107 DH |
599 | r = 0; |
600 | i_head++; | |
601 | } while (n); | |
78e1f386 | 602 | i->count -= bytes; |
52cbd23a WB |
603 | csstate->csum = sum; |
604 | csstate->off = off; | |
78e1f386 AV |
605 | return bytes; |
606 | } | |
607 | ||
aa28de27 | 608 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 609 | { |
36f7a8a4 | 610 | const char *from = addr; |
00e23707 | 611 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 612 | return copy_pipe_to_iter(addr, bytes, i); |
09fc68dc AV |
613 | if (iter_is_iovec(i)) |
614 | might_fault(); | |
3d4d3e48 | 615 | iterate_and_advance(i, bytes, v, |
09fc68dc | 616 | copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
21b56c84 | 617 | memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len) |
3d4d3e48 | 618 | ) |
62a8067a | 619 | |
3d4d3e48 | 620 | return bytes; |
c35e0248 | 621 | } |
aa28de27 | 622 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 623 | |
ec6347bb DW |
624 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
625 | static int copyout_mc(void __user *to, const void *from, size_t n) | |
8780356e | 626 | { |
96d4f267 | 627 | if (access_ok(to, n)) { |
d0ef4c36 | 628 | instrument_copy_to_user(to, from, n); |
ec6347bb | 629 | n = copy_mc_to_user((__force void *) to, from, n); |
8780356e DW |
630 | } |
631 | return n; | |
632 | } | |
633 | ||
ec6347bb | 634 | static unsigned long copy_mc_to_page(struct page *page, size_t offset, |
8780356e DW |
635 | const char *from, size_t len) |
636 | { | |
637 | unsigned long ret; | |
638 | char *to; | |
639 | ||
640 | to = kmap_atomic(page); | |
ec6347bb | 641 | ret = copy_mc_to_kernel(to + offset, from, len); |
8780356e DW |
642 | kunmap_atomic(to); |
643 | ||
644 | return ret; | |
645 | } | |
646 | ||
ec6347bb | 647 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
ca146f6f DW |
648 | struct iov_iter *i) |
649 | { | |
650 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
651 | unsigned int p_mask = pipe->ring_size - 1; |
652 | unsigned int i_head; | |
ca146f6f | 653 | size_t n, off, xfer = 0; |
ca146f6f DW |
654 | |
655 | if (!sanity(i)) | |
656 | return 0; | |
657 | ||
8cefc107 | 658 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
ca146f6f DW |
659 | if (unlikely(!n)) |
660 | return 0; | |
8cefc107 | 661 | do { |
ca146f6f DW |
662 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
663 | unsigned long rem; | |
664 | ||
ec6347bb | 665 | rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, |
8cefc107 DH |
666 | off, addr, chunk); |
667 | i->head = i_head; | |
ca146f6f DW |
668 | i->iov_offset = off + chunk - rem; |
669 | xfer += chunk - rem; | |
670 | if (rem) | |
671 | break; | |
672 | n -= chunk; | |
673 | addr += chunk; | |
8cefc107 DH |
674 | off = 0; |
675 | i_head++; | |
676 | } while (n); | |
ca146f6f DW |
677 | i->count -= xfer; |
678 | return xfer; | |
679 | } | |
680 | ||
bf3eeb9b | 681 | /** |
ec6347bb | 682 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
bf3eeb9b DW |
683 | * @addr: source kernel address |
684 | * @bytes: total transfer length | |
685 | * @iter: destination iterator | |
686 | * | |
ec6347bb DW |
687 | * The pmem driver deploys this for the dax operation |
688 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the | |
689 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes | |
690 | * successfully copied. | |
bf3eeb9b | 691 | * |
ec6347bb | 692 | * The main differences between this and typical _copy_to_iter(). |
bf3eeb9b DW |
693 | * |
694 | * * Typical tail/residue handling after a fault retries the copy | |
695 | * byte-by-byte until the fault happens again. Re-triggering machine | |
696 | * checks is potentially fatal so the implementation uses source | |
697 | * alignment and poison alignment assumptions to avoid re-triggering | |
698 | * hardware exceptions. | |
699 | * | |
700 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. | |
701 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return | |
702 | * a short copy. | |
bf3eeb9b | 703 | */ |
ec6347bb | 704 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
8780356e DW |
705 | { |
706 | const char *from = addr; | |
8780356e | 707 | |
00e23707 | 708 | if (unlikely(iov_iter_is_pipe(i))) |
ec6347bb | 709 | return copy_mc_pipe_to_iter(addr, bytes, i); |
8780356e DW |
710 | if (iter_is_iovec(i)) |
711 | might_fault(); | |
1b4fb5ff | 712 | __iterate_and_advance(i, bytes, v, |
ec6347bb DW |
713 | copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, |
714 | v.iov_len), | |
1b4fb5ff | 715 | copy_mc_to_kernel(v.iov_base, (from += v.iov_len) |
21b56c84 | 716 | - v.iov_len, v.iov_len) |
8780356e DW |
717 | ) |
718 | ||
719 | return bytes; | |
720 | } | |
ec6347bb DW |
721 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
722 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 723 | |
aa28de27 | 724 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 725 | { |
0dbca9a4 | 726 | char *to = addr; |
00e23707 | 727 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
728 | WARN_ON(1); |
729 | return 0; | |
730 | } | |
09fc68dc AV |
731 | if (iter_is_iovec(i)) |
732 | might_fault(); | |
0dbca9a4 | 733 | iterate_and_advance(i, bytes, v, |
09fc68dc | 734 | copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
21b56c84 | 735 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
0dbca9a4 AV |
736 | ) |
737 | ||
738 | return bytes; | |
c35e0248 | 739 | } |
aa28de27 | 740 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 741 | |
aa28de27 | 742 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 AV |
743 | { |
744 | char *to = addr; | |
00e23707 | 745 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
746 | WARN_ON(1); |
747 | return 0; | |
748 | } | |
aa583096 | 749 | iterate_and_advance(i, bytes, v, |
3f763453 | 750 | __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
aa583096 | 751 | v.iov_base, v.iov_len), |
21b56c84 | 752 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
aa583096 AV |
753 | ) |
754 | ||
755 | return bytes; | |
756 | } | |
aa28de27 | 757 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 758 | |
0aed55af | 759 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
760 | /** |
761 | * _copy_from_iter_flushcache - write destination through cpu cache | |
762 | * @addr: destination kernel address | |
763 | * @bytes: total transfer length | |
764 | * @iter: source iterator | |
765 | * | |
766 | * The pmem driver arranges for filesystem-dax to use this facility via | |
767 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
768 | * are flushed through the CPU cache. It is differentiated from | |
769 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
770 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
771 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
772 | * instructions that strand dirty-data in the cache. | |
773 | */ | |
6a37e940 | 774 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af DW |
775 | { |
776 | char *to = addr; | |
00e23707 | 777 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
778 | WARN_ON(1); |
779 | return 0; | |
780 | } | |
781 | iterate_and_advance(i, bytes, v, | |
782 | __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, | |
783 | v.iov_base, v.iov_len), | |
0aed55af | 784 | memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, |
21b56c84 | 785 | v.iov_len) |
0aed55af DW |
786 | ) |
787 | ||
788 | return bytes; | |
789 | } | |
6a37e940 | 790 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
791 | #endif |
792 | ||
72e809ed AV |
793 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
794 | { | |
6daef95b ED |
795 | struct page *head; |
796 | size_t v = n + offset; | |
797 | ||
798 | /* | |
799 | * The general case needs to access the page order in order | |
800 | * to compute the page size. | |
801 | * However, we mostly deal with order-0 pages and thus can | |
802 | * avoid a possible cache line miss for requests that fit all | |
803 | * page orders. | |
804 | */ | |
805 | if (n <= v && v <= PAGE_SIZE) | |
806 | return true; | |
807 | ||
808 | head = compound_head(page); | |
809 | v += (page - head) << PAGE_SHIFT; | |
a90bcb86 | 810 | |
a50b854e | 811 | if (likely(n <= v && v <= (page_size(head)))) |
72e809ed AV |
812 | return true; |
813 | WARN_ON(1); | |
814 | return false; | |
815 | } | |
cbbd26b8 | 816 | |
08aa6479 | 817 | static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
62a8067a AV |
818 | struct iov_iter *i) |
819 | { | |
28f38db7 AV |
820 | if (likely(iter_is_iovec(i))) |
821 | return copy_page_to_iter_iovec(page, offset, bytes, i); | |
822 | if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { | |
d271524a AV |
823 | void *kaddr = kmap_atomic(page); |
824 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); | |
825 | kunmap_atomic(kaddr); | |
826 | return wanted; | |
28f38db7 AV |
827 | } |
828 | if (iov_iter_is_pipe(i)) | |
829 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
830 | if (unlikely(iov_iter_is_discard(i))) { | |
a506abc7 AV |
831 | if (unlikely(i->count < bytes)) |
832 | bytes = i->count; | |
833 | i->count -= bytes; | |
9ea9ce04 | 834 | return bytes; |
28f38db7 AV |
835 | } |
836 | WARN_ON(1); | |
837 | return 0; | |
62a8067a | 838 | } |
08aa6479 AV |
839 | |
840 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, | |
841 | struct iov_iter *i) | |
842 | { | |
843 | size_t res = 0; | |
844 | if (unlikely(!page_copy_sane(page, offset, bytes))) | |
845 | return 0; | |
846 | page += offset / PAGE_SIZE; // first subpage | |
847 | offset %= PAGE_SIZE; | |
848 | while (1) { | |
849 | size_t n = __copy_page_to_iter(page, offset, | |
850 | min(bytes, (size_t)PAGE_SIZE - offset), i); | |
851 | res += n; | |
852 | bytes -= n; | |
853 | if (!bytes || !n) | |
854 | break; | |
855 | offset += n; | |
856 | if (offset == PAGE_SIZE) { | |
857 | page++; | |
858 | offset = 0; | |
859 | } | |
860 | } | |
861 | return res; | |
862 | } | |
62a8067a AV |
863 | EXPORT_SYMBOL(copy_page_to_iter); |
864 | ||
865 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
866 | struct iov_iter *i) | |
867 | { | |
72e809ed AV |
868 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
869 | return 0; | |
28f38db7 AV |
870 | if (likely(iter_is_iovec(i))) |
871 | return copy_page_from_iter_iovec(page, offset, bytes, i); | |
872 | if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { | |
d271524a | 873 | void *kaddr = kmap_atomic(page); |
aa28de27 | 874 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
d271524a AV |
875 | kunmap_atomic(kaddr); |
876 | return wanted; | |
28f38db7 AV |
877 | } |
878 | WARN_ON(1); | |
879 | return 0; | |
62a8067a AV |
880 | } |
881 | EXPORT_SYMBOL(copy_page_from_iter); | |
882 | ||
241699cd AV |
883 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
884 | { | |
885 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
886 | unsigned int p_mask = pipe->ring_size - 1; |
887 | unsigned int i_head; | |
241699cd | 888 | size_t n, off; |
241699cd AV |
889 | |
890 | if (!sanity(i)) | |
891 | return 0; | |
892 | ||
8cefc107 | 893 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
894 | if (unlikely(!n)) |
895 | return 0; | |
896 | ||
8cefc107 | 897 | do { |
241699cd | 898 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
899 | memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); |
900 | i->head = i_head; | |
241699cd AV |
901 | i->iov_offset = off + chunk; |
902 | n -= chunk; | |
8cefc107 DH |
903 | off = 0; |
904 | i_head++; | |
905 | } while (n); | |
241699cd AV |
906 | i->count -= bytes; |
907 | return bytes; | |
908 | } | |
909 | ||
c35e0248 MW |
910 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
911 | { | |
00e23707 | 912 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 913 | return pipe_zero(bytes, i); |
8442fa46 | 914 | iterate_and_advance(i, bytes, v, |
09fc68dc | 915 | clear_user(v.iov_base, v.iov_len), |
21b56c84 | 916 | memset(v.iov_base, 0, v.iov_len) |
8442fa46 AV |
917 | ) |
918 | ||
919 | return bytes; | |
c35e0248 MW |
920 | } |
921 | EXPORT_SYMBOL(iov_iter_zero); | |
922 | ||
f0b65f39 AV |
923 | size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, |
924 | struct iov_iter *i) | |
62a8067a | 925 | { |
04a31165 | 926 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
927 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
928 | kunmap_atomic(kaddr); | |
929 | return 0; | |
930 | } | |
9ea9ce04 | 931 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
932 | kunmap_atomic(kaddr); |
933 | WARN_ON(1); | |
934 | return 0; | |
935 | } | |
f0b65f39 | 936 | iterate_and_advance(i, bytes, v, |
09fc68dc | 937 | copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
21b56c84 | 938 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
04a31165 AV |
939 | ) |
940 | kunmap_atomic(kaddr); | |
941 | return bytes; | |
62a8067a | 942 | } |
f0b65f39 | 943 | EXPORT_SYMBOL(copy_page_from_iter_atomic); |
62a8067a | 944 | |
b9dc6f65 AV |
945 | static inline void pipe_truncate(struct iov_iter *i) |
946 | { | |
947 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
948 | unsigned int p_tail = pipe->tail; |
949 | unsigned int p_head = pipe->head; | |
950 | unsigned int p_mask = pipe->ring_size - 1; | |
951 | ||
952 | if (!pipe_empty(p_head, p_tail)) { | |
953 | struct pipe_buffer *buf; | |
954 | unsigned int i_head = i->head; | |
b9dc6f65 | 955 | size_t off = i->iov_offset; |
8cefc107 | 956 | |
b9dc6f65 | 957 | if (off) { |
8cefc107 DH |
958 | buf = &pipe->bufs[i_head & p_mask]; |
959 | buf->len = off - buf->offset; | |
960 | i_head++; | |
b9dc6f65 | 961 | } |
8cefc107 DH |
962 | while (p_head != i_head) { |
963 | p_head--; | |
964 | pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); | |
b9dc6f65 | 965 | } |
8cefc107 DH |
966 | |
967 | pipe->head = p_head; | |
b9dc6f65 AV |
968 | } |
969 | } | |
970 | ||
241699cd AV |
971 | static void pipe_advance(struct iov_iter *i, size_t size) |
972 | { | |
973 | struct pipe_inode_info *pipe = i->pipe; | |
241699cd | 974 | if (size) { |
b9dc6f65 | 975 | struct pipe_buffer *buf; |
8cefc107 DH |
976 | unsigned int p_mask = pipe->ring_size - 1; |
977 | unsigned int i_head = i->head; | |
b9dc6f65 | 978 | size_t off = i->iov_offset, left = size; |
8cefc107 | 979 | |
241699cd | 980 | if (off) /* make it relative to the beginning of buffer */ |
8cefc107 | 981 | left += off - pipe->bufs[i_head & p_mask].offset; |
241699cd | 982 | while (1) { |
8cefc107 | 983 | buf = &pipe->bufs[i_head & p_mask]; |
b9dc6f65 | 984 | if (left <= buf->len) |
241699cd | 985 | break; |
b9dc6f65 | 986 | left -= buf->len; |
8cefc107 | 987 | i_head++; |
241699cd | 988 | } |
8cefc107 | 989 | i->head = i_head; |
b9dc6f65 | 990 | i->iov_offset = buf->offset + left; |
241699cd | 991 | } |
b9dc6f65 AV |
992 | i->count -= size; |
993 | /* ... and discard everything past that point */ | |
994 | pipe_truncate(i); | |
241699cd AV |
995 | } |
996 | ||
54c8195b PB |
997 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
998 | { | |
999 | struct bvec_iter bi; | |
1000 | ||
1001 | bi.bi_size = i->count; | |
1002 | bi.bi_bvec_done = i->iov_offset; | |
1003 | bi.bi_idx = 0; | |
1004 | bvec_iter_advance(i->bvec, &bi, size); | |
1005 | ||
1006 | i->bvec += bi.bi_idx; | |
1007 | i->nr_segs -= bi.bi_idx; | |
1008 | i->count = bi.bi_size; | |
1009 | i->iov_offset = bi.bi_bvec_done; | |
1010 | } | |
1011 | ||
185ac4d4 AV |
1012 | static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) |
1013 | { | |
1014 | const struct iovec *iov, *end; | |
1015 | ||
1016 | if (!i->count) | |
1017 | return; | |
1018 | i->count -= size; | |
1019 | ||
1020 | size += i->iov_offset; // from beginning of current segment | |
1021 | for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { | |
1022 | if (likely(size < iov->iov_len)) | |
1023 | break; | |
1024 | size -= iov->iov_len; | |
1025 | } | |
1026 | i->iov_offset = size; | |
1027 | i->nr_segs -= iov - i->iov; | |
1028 | i->iov = iov; | |
1029 | } | |
1030 | ||
62a8067a AV |
1031 | void iov_iter_advance(struct iov_iter *i, size_t size) |
1032 | { | |
3b3fc051 AV |
1033 | if (unlikely(i->count < size)) |
1034 | size = i->count; | |
185ac4d4 AV |
1035 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { |
1036 | /* iovec and kvec have identical layouts */ | |
1037 | iov_iter_iovec_advance(i, size); | |
1038 | } else if (iov_iter_is_bvec(i)) { | |
1039 | iov_iter_bvec_advance(i, size); | |
1040 | } else if (iov_iter_is_pipe(i)) { | |
241699cd | 1041 | pipe_advance(i, size); |
185ac4d4 | 1042 | } else if (unlikely(iov_iter_is_xarray(i))) { |
7ff50620 DH |
1043 | i->iov_offset += size; |
1044 | i->count -= size; | |
185ac4d4 AV |
1045 | } else if (iov_iter_is_discard(i)) { |
1046 | i->count -= size; | |
54c8195b | 1047 | } |
62a8067a AV |
1048 | } |
1049 | EXPORT_SYMBOL(iov_iter_advance); | |
1050 | ||
27c0e374 AV |
1051 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
1052 | { | |
1053 | if (!unroll) | |
1054 | return; | |
5b47d59a AV |
1055 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
1056 | return; | |
27c0e374 | 1057 | i->count += unroll; |
00e23707 | 1058 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 | 1059 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 DH |
1060 | unsigned int p_mask = pipe->ring_size - 1; |
1061 | unsigned int i_head = i->head; | |
27c0e374 AV |
1062 | size_t off = i->iov_offset; |
1063 | while (1) { | |
8cefc107 DH |
1064 | struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; |
1065 | size_t n = off - b->offset; | |
27c0e374 | 1066 | if (unroll < n) { |
4fa55cef | 1067 | off -= unroll; |
27c0e374 AV |
1068 | break; |
1069 | } | |
1070 | unroll -= n; | |
8cefc107 | 1071 | if (!unroll && i_head == i->start_head) { |
27c0e374 AV |
1072 | off = 0; |
1073 | break; | |
1074 | } | |
8cefc107 DH |
1075 | i_head--; |
1076 | b = &pipe->bufs[i_head & p_mask]; | |
1077 | off = b->offset + b->len; | |
27c0e374 AV |
1078 | } |
1079 | i->iov_offset = off; | |
8cefc107 | 1080 | i->head = i_head; |
27c0e374 AV |
1081 | pipe_truncate(i); |
1082 | return; | |
1083 | } | |
9ea9ce04 DH |
1084 | if (unlikely(iov_iter_is_discard(i))) |
1085 | return; | |
27c0e374 AV |
1086 | if (unroll <= i->iov_offset) { |
1087 | i->iov_offset -= unroll; | |
1088 | return; | |
1089 | } | |
1090 | unroll -= i->iov_offset; | |
7ff50620 DH |
1091 | if (iov_iter_is_xarray(i)) { |
1092 | BUG(); /* We should never go beyond the start of the specified | |
1093 | * range since we might then be straying into pages that | |
1094 | * aren't pinned. | |
1095 | */ | |
1096 | } else if (iov_iter_is_bvec(i)) { | |
27c0e374 AV |
1097 | const struct bio_vec *bvec = i->bvec; |
1098 | while (1) { | |
1099 | size_t n = (--bvec)->bv_len; | |
1100 | i->nr_segs++; | |
1101 | if (unroll <= n) { | |
1102 | i->bvec = bvec; | |
1103 | i->iov_offset = n - unroll; | |
1104 | return; | |
1105 | } | |
1106 | unroll -= n; | |
1107 | } | |
1108 | } else { /* same logics for iovec and kvec */ | |
1109 | const struct iovec *iov = i->iov; | |
1110 | while (1) { | |
1111 | size_t n = (--iov)->iov_len; | |
1112 | i->nr_segs++; | |
1113 | if (unroll <= n) { | |
1114 | i->iov = iov; | |
1115 | i->iov_offset = n - unroll; | |
1116 | return; | |
1117 | } | |
1118 | unroll -= n; | |
1119 | } | |
1120 | } | |
1121 | } | |
1122 | EXPORT_SYMBOL(iov_iter_revert); | |
1123 | ||
62a8067a AV |
1124 | /* |
1125 | * Return the count of just the current iov_iter segment. | |
1126 | */ | |
1127 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
1128 | { | |
28f38db7 AV |
1129 | if (i->nr_segs > 1) { |
1130 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1131 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
1132 | if (iov_iter_is_bvec(i)) | |
1133 | return min(i->count, i->bvec->bv_len - i->iov_offset); | |
1134 | } | |
1135 | return i->count; | |
62a8067a AV |
1136 | } |
1137 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
1138 | ||
aa563d7b | 1139 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 1140 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
1141 | size_t count) |
1142 | { | |
aa563d7b | 1143 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
1144 | *i = (struct iov_iter){ |
1145 | .iter_type = ITER_KVEC, | |
1146 | .data_source = direction, | |
1147 | .kvec = kvec, | |
1148 | .nr_segs = nr_segs, | |
1149 | .iov_offset = 0, | |
1150 | .count = count | |
1151 | }; | |
abb78f87 AV |
1152 | } |
1153 | EXPORT_SYMBOL(iov_iter_kvec); | |
1154 | ||
aa563d7b | 1155 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1156 | const struct bio_vec *bvec, unsigned long nr_segs, |
1157 | size_t count) | |
1158 | { | |
aa563d7b | 1159 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
1160 | *i = (struct iov_iter){ |
1161 | .iter_type = ITER_BVEC, | |
1162 | .data_source = direction, | |
1163 | .bvec = bvec, | |
1164 | .nr_segs = nr_segs, | |
1165 | .iov_offset = 0, | |
1166 | .count = count | |
1167 | }; | |
05afcb77 AV |
1168 | } |
1169 | EXPORT_SYMBOL(iov_iter_bvec); | |
1170 | ||
aa563d7b | 1171 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1172 | struct pipe_inode_info *pipe, |
1173 | size_t count) | |
1174 | { | |
aa563d7b | 1175 | BUG_ON(direction != READ); |
8cefc107 | 1176 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
8cd54c1c AV |
1177 | *i = (struct iov_iter){ |
1178 | .iter_type = ITER_PIPE, | |
1179 | .data_source = false, | |
1180 | .pipe = pipe, | |
1181 | .head = pipe->head, | |
1182 | .start_head = pipe->head, | |
1183 | .iov_offset = 0, | |
1184 | .count = count | |
1185 | }; | |
241699cd AV |
1186 | } |
1187 | EXPORT_SYMBOL(iov_iter_pipe); | |
1188 | ||
7ff50620 DH |
1189 | /** |
1190 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray | |
1191 | * @i: The iterator to initialise. | |
1192 | * @direction: The direction of the transfer. | |
1193 | * @xarray: The xarray to access. | |
1194 | * @start: The start file position. | |
1195 | * @count: The size of the I/O buffer in bytes. | |
1196 | * | |
1197 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
1198 | * inode or to inject data into those pages. The pages *must* be prevented | |
1199 | * from evaporation, either by taking a ref on them or locking them by the | |
1200 | * caller. | |
1201 | */ | |
1202 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, | |
1203 | struct xarray *xarray, loff_t start, size_t count) | |
1204 | { | |
1205 | BUG_ON(direction & ~1); | |
8cd54c1c AV |
1206 | *i = (struct iov_iter) { |
1207 | .iter_type = ITER_XARRAY, | |
1208 | .data_source = direction, | |
1209 | .xarray = xarray, | |
1210 | .xarray_start = start, | |
1211 | .count = count, | |
1212 | .iov_offset = 0 | |
1213 | }; | |
7ff50620 DH |
1214 | } |
1215 | EXPORT_SYMBOL(iov_iter_xarray); | |
1216 | ||
9ea9ce04 DH |
1217 | /** |
1218 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
1219 | * @i: The iterator to initialise. | |
1220 | * @direction: The direction of the transfer. | |
1221 | * @count: The size of the I/O buffer in bytes. | |
1222 | * | |
1223 | * Set up an I/O iterator that just discards everything that's written to it. | |
1224 | * It's only available as a READ iterator. | |
1225 | */ | |
1226 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
1227 | { | |
1228 | BUG_ON(direction != READ); | |
8cd54c1c AV |
1229 | *i = (struct iov_iter){ |
1230 | .iter_type = ITER_DISCARD, | |
1231 | .data_source = false, | |
1232 | .count = count, | |
1233 | .iov_offset = 0 | |
1234 | }; | |
9ea9ce04 DH |
1235 | } |
1236 | EXPORT_SYMBOL(iov_iter_discard); | |
1237 | ||
9221d2e3 | 1238 | static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) |
62a8067a | 1239 | { |
04a31165 AV |
1240 | unsigned long res = 0; |
1241 | size_t size = i->count; | |
9221d2e3 AV |
1242 | size_t skip = i->iov_offset; |
1243 | unsigned k; | |
1244 | ||
1245 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1246 | size_t len = i->iov[k].iov_len - skip; | |
1247 | if (len) { | |
1248 | res |= (unsigned long)i->iov[k].iov_base + skip; | |
1249 | if (len > size) | |
1250 | len = size; | |
1251 | res |= len; | |
1252 | size -= len; | |
1253 | if (!size) | |
1254 | break; | |
1255 | } | |
1256 | } | |
1257 | return res; | |
1258 | } | |
04a31165 | 1259 | |
9221d2e3 AV |
1260 | static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) |
1261 | { | |
1262 | unsigned res = 0; | |
1263 | size_t size = i->count; | |
1264 | unsigned skip = i->iov_offset; | |
1265 | unsigned k; | |
1266 | ||
1267 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1268 | size_t len = i->bvec[k].bv_len - skip; | |
1269 | res |= (unsigned long)i->bvec[k].bv_offset + skip; | |
1270 | if (len > size) | |
1271 | len = size; | |
1272 | res |= len; | |
1273 | size -= len; | |
1274 | if (!size) | |
1275 | break; | |
1276 | } | |
1277 | return res; | |
1278 | } | |
1279 | ||
1280 | unsigned long iov_iter_alignment(const struct iov_iter *i) | |
1281 | { | |
1282 | /* iovec and kvec have identical layouts */ | |
1283 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1284 | return iov_iter_alignment_iovec(i); | |
1285 | ||
1286 | if (iov_iter_is_bvec(i)) | |
1287 | return iov_iter_alignment_bvec(i); | |
1288 | ||
1289 | if (iov_iter_is_pipe(i)) { | |
e0ff126e | 1290 | unsigned int p_mask = i->pipe->ring_size - 1; |
9221d2e3 | 1291 | size_t size = i->count; |
e0ff126e | 1292 | |
8cefc107 | 1293 | if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) |
241699cd AV |
1294 | return size | i->iov_offset; |
1295 | return size; | |
1296 | } | |
9221d2e3 AV |
1297 | |
1298 | if (iov_iter_is_xarray(i)) | |
3d14ec1f | 1299 | return (i->xarray_start + i->iov_offset) | i->count; |
9221d2e3 AV |
1300 | |
1301 | return 0; | |
62a8067a AV |
1302 | } |
1303 | EXPORT_SYMBOL(iov_iter_alignment); | |
1304 | ||
357f435d AV |
1305 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1306 | { | |
33844e66 | 1307 | unsigned long res = 0; |
610c7a71 | 1308 | unsigned long v = 0; |
357f435d | 1309 | size_t size = i->count; |
610c7a71 | 1310 | unsigned k; |
357f435d | 1311 | |
610c7a71 | 1312 | if (WARN_ON(!iter_is_iovec(i))) |
241699cd | 1313 | return ~0U; |
241699cd | 1314 | |
610c7a71 AV |
1315 | for (k = 0; k < i->nr_segs; k++) { |
1316 | if (i->iov[k].iov_len) { | |
1317 | unsigned long base = (unsigned long)i->iov[k].iov_base; | |
1318 | if (v) // if not the first one | |
1319 | res |= base | v; // this start | previous end | |
1320 | v = base + i->iov[k].iov_len; | |
1321 | if (size <= i->iov[k].iov_len) | |
1322 | break; | |
1323 | size -= i->iov[k].iov_len; | |
1324 | } | |
1325 | } | |
33844e66 | 1326 | return res; |
357f435d AV |
1327 | } |
1328 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1329 | ||
e76b6312 | 1330 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
241699cd AV |
1331 | size_t maxsize, |
1332 | struct page **pages, | |
8cefc107 | 1333 | int iter_head, |
241699cd AV |
1334 | size_t *start) |
1335 | { | |
1336 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1337 | unsigned int p_mask = pipe->ring_size - 1; |
1338 | ssize_t n = push_pipe(i, maxsize, &iter_head, start); | |
241699cd AV |
1339 | if (!n) |
1340 | return -EFAULT; | |
1341 | ||
1342 | maxsize = n; | |
1343 | n += *start; | |
1689c73a | 1344 | while (n > 0) { |
8cefc107 DH |
1345 | get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); |
1346 | iter_head++; | |
241699cd AV |
1347 | n -= PAGE_SIZE; |
1348 | } | |
1349 | ||
1350 | return maxsize; | |
1351 | } | |
1352 | ||
1353 | static ssize_t pipe_get_pages(struct iov_iter *i, | |
1354 | struct page **pages, size_t maxsize, unsigned maxpages, | |
1355 | size_t *start) | |
1356 | { | |
8cefc107 | 1357 | unsigned int iter_head, npages; |
241699cd | 1358 | size_t capacity; |
241699cd AV |
1359 | |
1360 | if (!sanity(i)) | |
1361 | return -EFAULT; | |
1362 | ||
8cefc107 DH |
1363 | data_start(i, &iter_head, start); |
1364 | /* Amount of free space: some of this one + all after this one */ | |
1365 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
1366 | capacity = min(npages, maxpages) * PAGE_SIZE - *start; | |
241699cd | 1367 | |
8cefc107 | 1368 | return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); |
241699cd AV |
1369 | } |
1370 | ||
7ff50620 DH |
1371 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
1372 | pgoff_t index, unsigned int nr_pages) | |
1373 | { | |
1374 | XA_STATE(xas, xa, index); | |
1375 | struct page *page; | |
1376 | unsigned int ret = 0; | |
1377 | ||
1378 | rcu_read_lock(); | |
1379 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1380 | if (xas_retry(&xas, page)) | |
1381 | continue; | |
1382 | ||
1383 | /* Has the page moved or been split? */ | |
1384 | if (unlikely(page != xas_reload(&xas))) { | |
1385 | xas_reset(&xas); | |
1386 | continue; | |
1387 | } | |
1388 | ||
1389 | pages[ret] = find_subpage(page, xas.xa_index); | |
1390 | get_page(pages[ret]); | |
1391 | if (++ret == nr_pages) | |
1392 | break; | |
1393 | } | |
1394 | rcu_read_unlock(); | |
1395 | return ret; | |
1396 | } | |
1397 | ||
1398 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, | |
1399 | struct page **pages, size_t maxsize, | |
1400 | unsigned maxpages, size_t *_start_offset) | |
1401 | { | |
1402 | unsigned nr, offset; | |
1403 | pgoff_t index, count; | |
1404 | size_t size = maxsize, actual; | |
1405 | loff_t pos; | |
1406 | ||
1407 | if (!size || !maxpages) | |
1408 | return 0; | |
1409 | ||
1410 | pos = i->xarray_start + i->iov_offset; | |
1411 | index = pos >> PAGE_SHIFT; | |
1412 | offset = pos & ~PAGE_MASK; | |
1413 | *_start_offset = offset; | |
1414 | ||
1415 | count = 1; | |
1416 | if (size > PAGE_SIZE - offset) { | |
1417 | size -= PAGE_SIZE - offset; | |
1418 | count += size >> PAGE_SHIFT; | |
1419 | size &= ~PAGE_MASK; | |
1420 | if (size) | |
1421 | count++; | |
1422 | } | |
1423 | ||
1424 | if (count > maxpages) | |
1425 | count = maxpages; | |
1426 | ||
1427 | nr = iter_xarray_populate_pages(pages, i->xarray, index, count); | |
1428 | if (nr == 0) | |
1429 | return 0; | |
1430 | ||
1431 | actual = PAGE_SIZE * nr; | |
1432 | actual -= offset; | |
1433 | if (nr == count && size > 0) { | |
1434 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1435 | actual -= PAGE_SIZE - (last_offset + size); | |
1436 | } | |
1437 | return actual; | |
1438 | } | |
1439 | ||
3d671ca6 AV |
1440 | /* must be done on non-empty ITER_IOVEC one */ |
1441 | static unsigned long first_iovec_segment(const struct iov_iter *i, | |
1442 | size_t *size, size_t *start, | |
1443 | size_t maxsize, unsigned maxpages) | |
1444 | { | |
1445 | size_t skip; | |
1446 | long k; | |
1447 | ||
1448 | for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { | |
1449 | unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; | |
1450 | size_t len = i->iov[k].iov_len - skip; | |
1451 | ||
1452 | if (unlikely(!len)) | |
1453 | continue; | |
1454 | if (len > maxsize) | |
1455 | len = maxsize; | |
1456 | len += (*start = addr % PAGE_SIZE); | |
1457 | if (len > maxpages * PAGE_SIZE) | |
1458 | len = maxpages * PAGE_SIZE; | |
1459 | *size = len; | |
1460 | return addr & PAGE_MASK; | |
1461 | } | |
1462 | BUG(); // if it had been empty, we wouldn't get called | |
1463 | } | |
1464 | ||
1465 | /* must be done on non-empty ITER_BVEC one */ | |
1466 | static struct page *first_bvec_segment(const struct iov_iter *i, | |
1467 | size_t *size, size_t *start, | |
1468 | size_t maxsize, unsigned maxpages) | |
1469 | { | |
1470 | struct page *page; | |
1471 | size_t skip = i->iov_offset, len; | |
1472 | ||
1473 | len = i->bvec->bv_len - skip; | |
1474 | if (len > maxsize) | |
1475 | len = maxsize; | |
1476 | skip += i->bvec->bv_offset; | |
1477 | page = i->bvec->bv_page + skip / PAGE_SIZE; | |
1478 | len += (*start = skip % PAGE_SIZE); | |
1479 | if (len > maxpages * PAGE_SIZE) | |
1480 | len = maxpages * PAGE_SIZE; | |
1481 | *size = len; | |
1482 | return page; | |
1483 | } | |
1484 | ||
62a8067a | 1485 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
2c80929c | 1486 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
1487 | size_t *start) |
1488 | { | |
3d671ca6 AV |
1489 | size_t len; |
1490 | int n, res; | |
1491 | ||
e5393fae AV |
1492 | if (maxsize > i->count) |
1493 | maxsize = i->count; | |
3d671ca6 AV |
1494 | if (!maxsize) |
1495 | return 0; | |
e5393fae | 1496 | |
3d671ca6 AV |
1497 | if (likely(iter_is_iovec(i))) { |
1498 | unsigned long addr; | |
e5393fae | 1499 | |
3d671ca6 | 1500 | addr = first_iovec_segment(i, &len, start, maxsize, maxpages); |
e5393fae | 1501 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
73b0140b IW |
1502 | res = get_user_pages_fast(addr, n, |
1503 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, | |
1504 | pages); | |
e5393fae AV |
1505 | if (unlikely(res < 0)) |
1506 | return res; | |
1507 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
3d671ca6 AV |
1508 | } |
1509 | if (iov_iter_is_bvec(i)) { | |
1510 | struct page *page; | |
1511 | ||
1512 | page = first_bvec_segment(i, &len, start, maxsize, maxpages); | |
1513 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1514 | while (n--) | |
1515 | get_page(*pages++ = page++); | |
1516 | return len - *start; | |
1517 | } | |
1518 | if (iov_iter_is_pipe(i)) | |
1519 | return pipe_get_pages(i, pages, maxsize, maxpages, start); | |
1520 | if (iov_iter_is_xarray(i)) | |
1521 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); | |
1522 | return -EFAULT; | |
62a8067a AV |
1523 | } |
1524 | EXPORT_SYMBOL(iov_iter_get_pages); | |
1525 | ||
1b17f1f2 AV |
1526 | static struct page **get_pages_array(size_t n) |
1527 | { | |
752ade68 | 1528 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); |
1b17f1f2 AV |
1529 | } |
1530 | ||
241699cd AV |
1531 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
1532 | struct page ***pages, size_t maxsize, | |
1533 | size_t *start) | |
1534 | { | |
1535 | struct page **p; | |
8cefc107 | 1536 | unsigned int iter_head, npages; |
d7760d63 | 1537 | ssize_t n; |
241699cd AV |
1538 | |
1539 | if (!sanity(i)) | |
1540 | return -EFAULT; | |
1541 | ||
8cefc107 DH |
1542 | data_start(i, &iter_head, start); |
1543 | /* Amount of free space: some of this one + all after this one */ | |
1544 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
241699cd AV |
1545 | n = npages * PAGE_SIZE - *start; |
1546 | if (maxsize > n) | |
1547 | maxsize = n; | |
1548 | else | |
1549 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); | |
1550 | p = get_pages_array(npages); | |
1551 | if (!p) | |
1552 | return -ENOMEM; | |
8cefc107 | 1553 | n = __pipe_get_pages(i, maxsize, p, iter_head, start); |
241699cd AV |
1554 | if (n > 0) |
1555 | *pages = p; | |
1556 | else | |
1557 | kvfree(p); | |
1558 | return n; | |
1559 | } | |
1560 | ||
7ff50620 DH |
1561 | static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, |
1562 | struct page ***pages, size_t maxsize, | |
1563 | size_t *_start_offset) | |
1564 | { | |
1565 | struct page **p; | |
1566 | unsigned nr, offset; | |
1567 | pgoff_t index, count; | |
1568 | size_t size = maxsize, actual; | |
1569 | loff_t pos; | |
1570 | ||
1571 | if (!size) | |
1572 | return 0; | |
1573 | ||
1574 | pos = i->xarray_start + i->iov_offset; | |
1575 | index = pos >> PAGE_SHIFT; | |
1576 | offset = pos & ~PAGE_MASK; | |
1577 | *_start_offset = offset; | |
1578 | ||
1579 | count = 1; | |
1580 | if (size > PAGE_SIZE - offset) { | |
1581 | size -= PAGE_SIZE - offset; | |
1582 | count += size >> PAGE_SHIFT; | |
1583 | size &= ~PAGE_MASK; | |
1584 | if (size) | |
1585 | count++; | |
1586 | } | |
1587 | ||
1588 | p = get_pages_array(count); | |
1589 | if (!p) | |
1590 | return -ENOMEM; | |
1591 | *pages = p; | |
1592 | ||
1593 | nr = iter_xarray_populate_pages(p, i->xarray, index, count); | |
1594 | if (nr == 0) | |
1595 | return 0; | |
1596 | ||
1597 | actual = PAGE_SIZE * nr; | |
1598 | actual -= offset; | |
1599 | if (nr == count && size > 0) { | |
1600 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1601 | actual -= PAGE_SIZE - (last_offset + size); | |
1602 | } | |
1603 | return actual; | |
1604 | } | |
1605 | ||
62a8067a AV |
1606 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
1607 | struct page ***pages, size_t maxsize, | |
1608 | size_t *start) | |
1609 | { | |
1b17f1f2 | 1610 | struct page **p; |
3d671ca6 AV |
1611 | size_t len; |
1612 | int n, res; | |
1b17f1f2 AV |
1613 | |
1614 | if (maxsize > i->count) | |
1615 | maxsize = i->count; | |
3d671ca6 AV |
1616 | if (!maxsize) |
1617 | return 0; | |
1b17f1f2 | 1618 | |
3d671ca6 AV |
1619 | if (likely(iter_is_iovec(i))) { |
1620 | unsigned long addr; | |
1b17f1f2 | 1621 | |
3d671ca6 | 1622 | addr = first_iovec_segment(i, &len, start, maxsize, ~0U); |
1b17f1f2 AV |
1623 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
1624 | p = get_pages_array(n); | |
1625 | if (!p) | |
1626 | return -ENOMEM; | |
73b0140b IW |
1627 | res = get_user_pages_fast(addr, n, |
1628 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); | |
1b17f1f2 AV |
1629 | if (unlikely(res < 0)) { |
1630 | kvfree(p); | |
1631 | return res; | |
1632 | } | |
1633 | *pages = p; | |
1634 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
3d671ca6 AV |
1635 | } |
1636 | if (iov_iter_is_bvec(i)) { | |
1637 | struct page *page; | |
1638 | ||
1639 | page = first_bvec_segment(i, &len, start, maxsize, ~0U); | |
1640 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1641 | *pages = p = get_pages_array(n); | |
1b17f1f2 AV |
1642 | if (!p) |
1643 | return -ENOMEM; | |
3d671ca6 AV |
1644 | while (n--) |
1645 | get_page(*p++ = page++); | |
1646 | return len - *start; | |
1647 | } | |
1648 | if (iov_iter_is_pipe(i)) | |
1649 | return pipe_get_pages_alloc(i, pages, maxsize, start); | |
1650 | if (iov_iter_is_xarray(i)) | |
1651 | return iter_xarray_get_pages_alloc(i, pages, maxsize, start); | |
1652 | return -EFAULT; | |
62a8067a AV |
1653 | } |
1654 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
1655 | ||
a604ec7e AV |
1656 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1657 | struct iov_iter *i) | |
1658 | { | |
1659 | char *to = addr; | |
1660 | __wsum sum, next; | |
1661 | size_t off = 0; | |
a604ec7e | 1662 | sum = *csum; |
9ea9ce04 | 1663 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1664 | WARN_ON(1); |
1665 | return 0; | |
1666 | } | |
a604ec7e | 1667 | iterate_and_advance(i, bytes, v, ({ |
cbbd26b8 | 1668 | next = csum_and_copy_from_user(v.iov_base, |
a604ec7e | 1669 | (to += v.iov_len) - v.iov_len, |
c693cc46 AV |
1670 | v.iov_len); |
1671 | if (next) { | |
a604ec7e AV |
1672 | sum = csum_block_add(sum, next, off); |
1673 | off += v.iov_len; | |
1674 | } | |
c693cc46 | 1675 | next ? 0 : v.iov_len; |
a604ec7e | 1676 | }), ({ |
f9152895 AV |
1677 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
1678 | v.iov_base, v.iov_len, | |
1679 | sum, off); | |
a604ec7e AV |
1680 | off += v.iov_len; |
1681 | }) | |
1682 | ) | |
1683 | *csum = sum; | |
1684 | return bytes; | |
1685 | } | |
1686 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1687 | ||
52cbd23a | 1688 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
a604ec7e AV |
1689 | struct iov_iter *i) |
1690 | { | |
52cbd23a | 1691 | struct csum_state *csstate = _csstate; |
36f7a8a4 | 1692 | const char *from = addr; |
a604ec7e | 1693 | __wsum sum, next; |
52cbd23a | 1694 | size_t off; |
78e1f386 AV |
1695 | |
1696 | if (unlikely(iov_iter_is_pipe(i))) | |
52cbd23a | 1697 | return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); |
78e1f386 | 1698 | |
594e450b AV |
1699 | sum = csum_shift(csstate->csum, csstate->off); |
1700 | off = 0; | |
78e1f386 | 1701 | if (unlikely(iov_iter_is_discard(i))) { |
241699cd AV |
1702 | WARN_ON(1); /* for now */ |
1703 | return 0; | |
1704 | } | |
a604ec7e | 1705 | iterate_and_advance(i, bytes, v, ({ |
a604ec7e | 1706 | next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, |
cbbd26b8 | 1707 | v.iov_base, |
c693cc46 AV |
1708 | v.iov_len); |
1709 | if (next) { | |
a604ec7e AV |
1710 | sum = csum_block_add(sum, next, off); |
1711 | off += v.iov_len; | |
1712 | } | |
c693cc46 | 1713 | next ? 0 : v.iov_len; |
a604ec7e | 1714 | }), ({ |
f9152895 AV |
1715 | sum = csum_and_memcpy(v.iov_base, |
1716 | (from += v.iov_len) - v.iov_len, | |
1717 | v.iov_len, sum, off); | |
a604ec7e AV |
1718 | off += v.iov_len; |
1719 | }) | |
1720 | ) | |
594e450b AV |
1721 | csstate->csum = csum_shift(sum, csstate->off); |
1722 | csstate->off += bytes; | |
a604ec7e AV |
1723 | return bytes; |
1724 | } | |
1725 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1726 | ||
d05f4435 SG |
1727 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
1728 | struct iov_iter *i) | |
1729 | { | |
7999096f | 1730 | #ifdef CONFIG_CRYPTO_HASH |
d05f4435 SG |
1731 | struct ahash_request *hash = hashp; |
1732 | struct scatterlist sg; | |
1733 | size_t copied; | |
1734 | ||
1735 | copied = copy_to_iter(addr, bytes, i); | |
1736 | sg_init_one(&sg, addr, copied); | |
1737 | ahash_request_set_crypt(hash, &sg, NULL, copied); | |
1738 | crypto_ahash_update(hash); | |
1739 | return copied; | |
27fad74a Y |
1740 | #else |
1741 | return 0; | |
1742 | #endif | |
d05f4435 SG |
1743 | } |
1744 | EXPORT_SYMBOL(hash_and_copy_to_iter); | |
1745 | ||
66531c65 | 1746 | static int iov_npages(const struct iov_iter *i, int maxpages) |
62a8067a | 1747 | { |
66531c65 AV |
1748 | size_t skip = i->iov_offset, size = i->count; |
1749 | const struct iovec *p; | |
e0f2dc40 AV |
1750 | int npages = 0; |
1751 | ||
66531c65 AV |
1752 | for (p = i->iov; size; skip = 0, p++) { |
1753 | unsigned offs = offset_in_page(p->iov_base + skip); | |
1754 | size_t len = min(p->iov_len - skip, size); | |
e0f2dc40 | 1755 | |
66531c65 AV |
1756 | if (len) { |
1757 | size -= len; | |
1758 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1759 | if (unlikely(npages > maxpages)) | |
1760 | return maxpages; | |
1761 | } | |
1762 | } | |
1763 | return npages; | |
1764 | } | |
1765 | ||
1766 | static int bvec_npages(const struct iov_iter *i, int maxpages) | |
1767 | { | |
1768 | size_t skip = i->iov_offset, size = i->count; | |
1769 | const struct bio_vec *p; | |
1770 | int npages = 0; | |
1771 | ||
1772 | for (p = i->bvec; size; skip = 0, p++) { | |
1773 | unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; | |
1774 | size_t len = min(p->bv_len - skip, size); | |
1775 | ||
1776 | size -= len; | |
1777 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1778 | if (unlikely(npages > maxpages)) | |
1779 | return maxpages; | |
1780 | } | |
1781 | return npages; | |
1782 | } | |
1783 | ||
1784 | int iov_iter_npages(const struct iov_iter *i, int maxpages) | |
1785 | { | |
1786 | if (unlikely(!i->count)) | |
1787 | return 0; | |
1788 | /* iovec and kvec have identical layouts */ | |
1789 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1790 | return iov_npages(i, maxpages); | |
1791 | if (iov_iter_is_bvec(i)) | |
1792 | return bvec_npages(i, maxpages); | |
1793 | if (iov_iter_is_pipe(i)) { | |
8cefc107 | 1794 | unsigned int iter_head; |
66531c65 | 1795 | int npages; |
241699cd | 1796 | size_t off; |
241699cd AV |
1797 | |
1798 | if (!sanity(i)) | |
1799 | return 0; | |
1800 | ||
8cefc107 | 1801 | data_start(i, &iter_head, &off); |
241699cd | 1802 | /* some of this one + all after this one */ |
66531c65 AV |
1803 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); |
1804 | return min(npages, maxpages); | |
1805 | } | |
1806 | if (iov_iter_is_xarray(i)) { | |
e4f8df86 AV |
1807 | unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; |
1808 | int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); | |
66531c65 AV |
1809 | return min(npages, maxpages); |
1810 | } | |
1811 | return 0; | |
62a8067a | 1812 | } |
f67da30c | 1813 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1814 | |
1815 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1816 | { | |
1817 | *new = *old; | |
00e23707 | 1818 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1819 | WARN_ON(1); |
1820 | return NULL; | |
1821 | } | |
7ff50620 | 1822 | if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) |
9ea9ce04 | 1823 | return NULL; |
00e23707 | 1824 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1825 | return new->bvec = kmemdup(new->bvec, |
1826 | new->nr_segs * sizeof(struct bio_vec), | |
1827 | flags); | |
1828 | else | |
1829 | /* iovec and kvec have identical layout */ | |
1830 | return new->iov = kmemdup(new->iov, | |
1831 | new->nr_segs * sizeof(struct iovec), | |
1832 | flags); | |
1833 | } | |
1834 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1835 | |
bfdc5970 CH |
1836 | static int copy_compat_iovec_from_user(struct iovec *iov, |
1837 | const struct iovec __user *uvec, unsigned long nr_segs) | |
1838 | { | |
1839 | const struct compat_iovec __user *uiov = | |
1840 | (const struct compat_iovec __user *)uvec; | |
1841 | int ret = -EFAULT, i; | |
1842 | ||
a959a978 | 1843 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
1844 | return -EFAULT; |
1845 | ||
1846 | for (i = 0; i < nr_segs; i++) { | |
1847 | compat_uptr_t buf; | |
1848 | compat_ssize_t len; | |
1849 | ||
1850 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); | |
1851 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); | |
1852 | ||
1853 | /* check for compat_size_t not fitting in compat_ssize_t .. */ | |
1854 | if (len < 0) { | |
1855 | ret = -EINVAL; | |
1856 | goto uaccess_end; | |
1857 | } | |
1858 | iov[i].iov_base = compat_ptr(buf); | |
1859 | iov[i].iov_len = len; | |
1860 | } | |
1861 | ||
1862 | ret = 0; | |
1863 | uaccess_end: | |
1864 | user_access_end(); | |
1865 | return ret; | |
1866 | } | |
1867 | ||
1868 | static int copy_iovec_from_user(struct iovec *iov, | |
1869 | const struct iovec __user *uvec, unsigned long nr_segs) | |
fb041b59 DL |
1870 | { |
1871 | unsigned long seg; | |
fb041b59 | 1872 | |
bfdc5970 CH |
1873 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
1874 | return -EFAULT; | |
1875 | for (seg = 0; seg < nr_segs; seg++) { | |
1876 | if ((ssize_t)iov[seg].iov_len < 0) | |
1877 | return -EINVAL; | |
fb041b59 DL |
1878 | } |
1879 | ||
bfdc5970 CH |
1880 | return 0; |
1881 | } | |
1882 | ||
1883 | struct iovec *iovec_from_user(const struct iovec __user *uvec, | |
1884 | unsigned long nr_segs, unsigned long fast_segs, | |
1885 | struct iovec *fast_iov, bool compat) | |
1886 | { | |
1887 | struct iovec *iov = fast_iov; | |
1888 | int ret; | |
1889 | ||
fb041b59 | 1890 | /* |
bfdc5970 CH |
1891 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
1892 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
1893 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 1894 | */ |
bfdc5970 CH |
1895 | if (nr_segs == 0) |
1896 | return iov; | |
1897 | if (nr_segs > UIO_MAXIOV) | |
1898 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
1899 | if (nr_segs > fast_segs) { |
1900 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
1901 | if (!iov) |
1902 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 1903 | } |
bfdc5970 CH |
1904 | |
1905 | if (compat) | |
1906 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); | |
1907 | else | |
1908 | ret = copy_iovec_from_user(iov, uvec, nr_segs); | |
1909 | if (ret) { | |
1910 | if (iov != fast_iov) | |
1911 | kfree(iov); | |
1912 | return ERR_PTR(ret); | |
1913 | } | |
1914 | ||
1915 | return iov; | |
1916 | } | |
1917 | ||
1918 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
1919 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
1920 | struct iov_iter *i, bool compat) | |
1921 | { | |
1922 | ssize_t total_len = 0; | |
1923 | unsigned long seg; | |
1924 | struct iovec *iov; | |
1925 | ||
1926 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); | |
1927 | if (IS_ERR(iov)) { | |
1928 | *iovp = NULL; | |
1929 | return PTR_ERR(iov); | |
fb041b59 DL |
1930 | } |
1931 | ||
1932 | /* | |
bfdc5970 CH |
1933 | * According to the Single Unix Specification we should return EINVAL if |
1934 | * an element length is < 0 when cast to ssize_t or if the total length | |
1935 | * would overflow the ssize_t return value of the system call. | |
fb041b59 DL |
1936 | * |
1937 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
1938 | * overflow case. | |
1939 | */ | |
fb041b59 | 1940 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
1941 | ssize_t len = (ssize_t)iov[seg].iov_len; |
1942 | ||
bfdc5970 CH |
1943 | if (!access_ok(iov[seg].iov_base, len)) { |
1944 | if (iov != *iovp) | |
1945 | kfree(iov); | |
1946 | *iovp = NULL; | |
1947 | return -EFAULT; | |
fb041b59 | 1948 | } |
bfdc5970 CH |
1949 | |
1950 | if (len > MAX_RW_COUNT - total_len) { | |
1951 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
1952 | iov[seg].iov_len = len; |
1953 | } | |
bfdc5970 | 1954 | total_len += len; |
fb041b59 | 1955 | } |
bfdc5970 CH |
1956 | |
1957 | iov_iter_init(i, type, iov, nr_segs, total_len); | |
1958 | if (iov == *iovp) | |
1959 | *iovp = NULL; | |
1960 | else | |
1961 | *iovp = iov; | |
1962 | return total_len; | |
fb041b59 DL |
1963 | } |
1964 | ||
ffecee4f VN |
1965 | /** |
1966 | * import_iovec() - Copy an array of &struct iovec from userspace | |
1967 | * into the kernel, check that it is valid, and initialize a new | |
1968 | * &struct iov_iter iterator to access it. | |
1969 | * | |
1970 | * @type: One of %READ or %WRITE. | |
bfdc5970 | 1971 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
1972 | * @nr_segs: Number of elements in userspace array. |
1973 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 1974 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
1975 | * on-stack) kernel array. |
1976 | * @i: Pointer to iterator that will be initialized on success. | |
1977 | * | |
1978 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
1979 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
1980 | * array will be allocated and the result placed in *@iov. This means that | |
1981 | * the caller may call kfree() on *@iov regardless of whether the small | |
1982 | * on-stack array was used or not (and regardless of whether this function | |
1983 | * returns an error or not). | |
1984 | * | |
87e5e6da | 1985 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 1986 | */ |
bfdc5970 | 1987 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 1988 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 1989 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 1990 | { |
89cd35c5 CH |
1991 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
1992 | in_compat_syscall()); | |
bc917be8 AV |
1993 | } |
1994 | EXPORT_SYMBOL(import_iovec); | |
1995 | ||
bc917be8 AV |
1996 | int import_single_range(int rw, void __user *buf, size_t len, |
1997 | struct iovec *iov, struct iov_iter *i) | |
1998 | { | |
1999 | if (len > MAX_RW_COUNT) | |
2000 | len = MAX_RW_COUNT; | |
96d4f267 | 2001 | if (unlikely(!access_ok(buf, len))) |
bc917be8 AV |
2002 | return -EFAULT; |
2003 | ||
2004 | iov->iov_base = buf; | |
2005 | iov->iov_len = len; | |
2006 | iov_iter_init(i, rw, iov, 1, len); | |
2007 | return 0; | |
2008 | } | |
e1267585 | 2009 | EXPORT_SYMBOL(import_single_range); |