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 */ |
a6e4ec7b | 20 | #define iterate_iovec(i, n, base, len, off, __p, STEP) { \ |
7baa5099 | 21 | size_t off = 0; \ |
a6e4ec7b | 22 | size_t skip = i->iov_offset; \ |
7a1bcb5d | 23 | do { \ |
7baa5099 AV |
24 | len = min(n, __p->iov_len - skip); \ |
25 | if (likely(len)) { \ | |
26 | base = __p->iov_base + skip; \ | |
27 | len -= (STEP); \ | |
28 | off += len; \ | |
29 | skip += len; \ | |
30 | n -= len; \ | |
7a1bcb5d AV |
31 | if (skip < __p->iov_len) \ |
32 | break; \ | |
33 | } \ | |
34 | __p++; \ | |
35 | skip = 0; \ | |
36 | } while (n); \ | |
a6e4ec7b | 37 | i->iov_offset = skip; \ |
7baa5099 | 38 | n = off; \ |
04a31165 AV |
39 | } |
40 | ||
a6e4ec7b | 41 | #define iterate_bvec(i, n, base, len, off, p, STEP) { \ |
7baa5099 | 42 | size_t off = 0; \ |
a6e4ec7b | 43 | unsigned skip = i->iov_offset; \ |
7491a2bf AV |
44 | while (n) { \ |
45 | unsigned offset = p->bv_offset + skip; \ | |
1b4fb5ff | 46 | unsigned left; \ |
21b56c84 AV |
47 | void *kaddr = kmap_local_page(p->bv_page + \ |
48 | offset / PAGE_SIZE); \ | |
7baa5099 | 49 | base = kaddr + offset % PAGE_SIZE; \ |
a6e4ec7b | 50 | len = min(min(n, (size_t)(p->bv_len - skip)), \ |
7491a2bf | 51 | (size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ |
1b4fb5ff | 52 | left = (STEP); \ |
21b56c84 | 53 | kunmap_local(kaddr); \ |
7baa5099 AV |
54 | len -= left; \ |
55 | off += len; \ | |
56 | skip += len; \ | |
7491a2bf AV |
57 | if (skip == p->bv_len) { \ |
58 | skip = 0; \ | |
59 | p++; \ | |
60 | } \ | |
7baa5099 | 61 | n -= len; \ |
1b4fb5ff AV |
62 | if (left) \ |
63 | break; \ | |
7491a2bf | 64 | } \ |
a6e4ec7b | 65 | i->iov_offset = skip; \ |
7baa5099 | 66 | n = off; \ |
04a31165 AV |
67 | } |
68 | ||
a6e4ec7b | 69 | #define iterate_xarray(i, n, base, len, __off, STEP) { \ |
1b4fb5ff | 70 | __label__ __out; \ |
622838f3 | 71 | size_t __off = 0; \ |
7ff50620 | 72 | struct page *head = NULL; \ |
a6e4ec7b | 73 | loff_t start = i->xarray_start + i->iov_offset; \ |
4b179e9a AV |
74 | unsigned offset = start % PAGE_SIZE; \ |
75 | pgoff_t index = start / PAGE_SIZE; \ | |
7ff50620 DH |
76 | int j; \ |
77 | \ | |
78 | XA_STATE(xas, i->xarray, index); \ | |
79 | \ | |
7baa5099 AV |
80 | rcu_read_lock(); \ |
81 | xas_for_each(&xas, head, ULONG_MAX) { \ | |
82 | unsigned left; \ | |
83 | if (xas_retry(&xas, head)) \ | |
84 | continue; \ | |
85 | if (WARN_ON(xa_is_value(head))) \ | |
86 | break; \ | |
87 | if (WARN_ON(PageHuge(head))) \ | |
88 | break; \ | |
7ff50620 | 89 | for (j = (head->index < index) ? index - head->index : 0; \ |
7baa5099 | 90 | j < thp_nr_pages(head); j++) { \ |
21b56c84 | 91 | void *kaddr = kmap_local_page(head + j); \ |
7baa5099 AV |
92 | base = kaddr + offset; \ |
93 | len = PAGE_SIZE - offset; \ | |
94 | len = min(n, len); \ | |
95 | left = (STEP); \ | |
96 | kunmap_local(kaddr); \ | |
97 | len -= left; \ | |
98 | __off += len; \ | |
99 | n -= len; \ | |
100 | if (left || n == 0) \ | |
101 | goto __out; \ | |
4b179e9a | 102 | offset = 0; \ |
7baa5099 | 103 | } \ |
7ff50620 | 104 | } \ |
1b4fb5ff | 105 | __out: \ |
7ff50620 | 106 | rcu_read_unlock(); \ |
a6e4ec7b | 107 | i->iov_offset += __off; \ |
622838f3 | 108 | n = __off; \ |
7ff50620 DH |
109 | } |
110 | ||
7baa5099 | 111 | #define __iterate_and_advance(i, n, base, len, off, I, K) { \ |
dd254f5a AV |
112 | if (unlikely(i->count < n)) \ |
113 | n = i->count; \ | |
f5da8354 | 114 | if (likely(n)) { \ |
28f38db7 | 115 | if (likely(iter_is_iovec(i))) { \ |
5c67aa90 | 116 | const struct iovec *iov = i->iov; \ |
7baa5099 AV |
117 | void __user *base; \ |
118 | size_t len; \ | |
119 | iterate_iovec(i, n, base, len, off, \ | |
a6e4ec7b | 120 | iov, (I)) \ |
28f38db7 AV |
121 | i->nr_segs -= iov - i->iov; \ |
122 | i->iov = iov; \ | |
123 | } else if (iov_iter_is_bvec(i)) { \ | |
1bdc76ae | 124 | const struct bio_vec *bvec = i->bvec; \ |
7baa5099 AV |
125 | void *base; \ |
126 | size_t len; \ | |
127 | iterate_bvec(i, n, base, len, off, \ | |
a6e4ec7b | 128 | bvec, (K)) \ |
7491a2bf AV |
129 | i->nr_segs -= bvec - i->bvec; \ |
130 | i->bvec = bvec; \ | |
28f38db7 | 131 | } else if (iov_iter_is_kvec(i)) { \ |
5c67aa90 | 132 | const struct kvec *kvec = i->kvec; \ |
7baa5099 AV |
133 | void *base; \ |
134 | size_t len; \ | |
135 | iterate_iovec(i, n, base, len, off, \ | |
a6e4ec7b | 136 | kvec, (K)) \ |
dd254f5a AV |
137 | i->nr_segs -= kvec - i->kvec; \ |
138 | i->kvec = kvec; \ | |
28f38db7 | 139 | } else if (iov_iter_is_xarray(i)) { \ |
7baa5099 AV |
140 | void *base; \ |
141 | size_t len; \ | |
142 | iterate_xarray(i, n, base, len, off, \ | |
a6e4ec7b | 143 | (K)) \ |
7ce2a91e | 144 | } \ |
dd254f5a | 145 | i->count -= n; \ |
7ce2a91e | 146 | } \ |
7ce2a91e | 147 | } |
7baa5099 AV |
148 | #define iterate_and_advance(i, n, base, len, off, I, K) \ |
149 | __iterate_and_advance(i, n, base, len, off, I, ((void)(K),0)) | |
7ce2a91e | 150 | |
09fc68dc AV |
151 | static int copyout(void __user *to, const void *from, size_t n) |
152 | { | |
4d0e9df5 AL |
153 | if (should_fail_usercopy()) |
154 | return n; | |
96d4f267 | 155 | if (access_ok(to, n)) { |
d0ef4c36 | 156 | instrument_copy_to_user(to, from, n); |
09fc68dc AV |
157 | n = raw_copy_to_user(to, from, n); |
158 | } | |
159 | return n; | |
160 | } | |
161 | ||
162 | static int copyin(void *to, const void __user *from, size_t n) | |
163 | { | |
4d0e9df5 AL |
164 | if (should_fail_usercopy()) |
165 | return n; | |
96d4f267 | 166 | if (access_ok(from, n)) { |
d0ef4c36 | 167 | instrument_copy_from_user(to, from, n); |
09fc68dc AV |
168 | n = raw_copy_from_user(to, from, n); |
169 | } | |
170 | return n; | |
171 | } | |
172 | ||
62a8067a | 173 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
174 | struct iov_iter *i) |
175 | { | |
176 | size_t skip, copy, left, wanted; | |
177 | const struct iovec *iov; | |
178 | char __user *buf; | |
179 | void *kaddr, *from; | |
180 | ||
181 | if (unlikely(bytes > i->count)) | |
182 | bytes = i->count; | |
183 | ||
184 | if (unlikely(!bytes)) | |
185 | return 0; | |
186 | ||
09fc68dc | 187 | might_fault(); |
4f18cd31 AV |
188 | wanted = bytes; |
189 | iov = i->iov; | |
190 | skip = i->iov_offset; | |
191 | buf = iov->iov_base + skip; | |
192 | copy = min(bytes, iov->iov_len - skip); | |
193 | ||
3fa6c507 | 194 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { |
4f18cd31 AV |
195 | kaddr = kmap_atomic(page); |
196 | from = kaddr + offset; | |
197 | ||
198 | /* first chunk, usually the only one */ | |
09fc68dc | 199 | left = copyout(buf, from, copy); |
4f18cd31 AV |
200 | copy -= left; |
201 | skip += copy; | |
202 | from += copy; | |
203 | bytes -= copy; | |
204 | ||
205 | while (unlikely(!left && bytes)) { | |
206 | iov++; | |
207 | buf = iov->iov_base; | |
208 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 209 | left = copyout(buf, from, copy); |
4f18cd31 AV |
210 | copy -= left; |
211 | skip = copy; | |
212 | from += copy; | |
213 | bytes -= copy; | |
214 | } | |
215 | if (likely(!bytes)) { | |
216 | kunmap_atomic(kaddr); | |
217 | goto done; | |
218 | } | |
219 | offset = from - kaddr; | |
220 | buf += copy; | |
221 | kunmap_atomic(kaddr); | |
222 | copy = min(bytes, iov->iov_len - skip); | |
223 | } | |
224 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 225 | |
4f18cd31 AV |
226 | kaddr = kmap(page); |
227 | from = kaddr + offset; | |
09fc68dc | 228 | left = copyout(buf, from, copy); |
4f18cd31 AV |
229 | copy -= left; |
230 | skip += copy; | |
231 | from += copy; | |
232 | bytes -= copy; | |
233 | while (unlikely(!left && bytes)) { | |
234 | iov++; | |
235 | buf = iov->iov_base; | |
236 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 237 | left = copyout(buf, from, copy); |
4f18cd31 AV |
238 | copy -= left; |
239 | skip = copy; | |
240 | from += copy; | |
241 | bytes -= copy; | |
242 | } | |
243 | kunmap(page); | |
3fa6c507 | 244 | |
4f18cd31 | 245 | done: |
81055e58 AV |
246 | if (skip == iov->iov_len) { |
247 | iov++; | |
248 | skip = 0; | |
249 | } | |
4f18cd31 AV |
250 | i->count -= wanted - bytes; |
251 | i->nr_segs -= iov - i->iov; | |
252 | i->iov = iov; | |
253 | i->iov_offset = skip; | |
254 | return wanted - bytes; | |
255 | } | |
4f18cd31 | 256 | |
62a8067a | 257 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
258 | struct iov_iter *i) |
259 | { | |
260 | size_t skip, copy, left, wanted; | |
261 | const struct iovec *iov; | |
262 | char __user *buf; | |
263 | void *kaddr, *to; | |
264 | ||
265 | if (unlikely(bytes > i->count)) | |
266 | bytes = i->count; | |
267 | ||
268 | if (unlikely(!bytes)) | |
269 | return 0; | |
270 | ||
09fc68dc | 271 | might_fault(); |
f0d1bec9 AV |
272 | wanted = bytes; |
273 | iov = i->iov; | |
274 | skip = i->iov_offset; | |
275 | buf = iov->iov_base + skip; | |
276 | copy = min(bytes, iov->iov_len - skip); | |
277 | ||
3fa6c507 | 278 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { |
f0d1bec9 AV |
279 | kaddr = kmap_atomic(page); |
280 | to = kaddr + offset; | |
281 | ||
282 | /* first chunk, usually the only one */ | |
09fc68dc | 283 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
284 | copy -= left; |
285 | skip += copy; | |
286 | to += copy; | |
287 | bytes -= copy; | |
288 | ||
289 | while (unlikely(!left && bytes)) { | |
290 | iov++; | |
291 | buf = iov->iov_base; | |
292 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 293 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
294 | copy -= left; |
295 | skip = copy; | |
296 | to += copy; | |
297 | bytes -= copy; | |
298 | } | |
299 | if (likely(!bytes)) { | |
300 | kunmap_atomic(kaddr); | |
301 | goto done; | |
302 | } | |
303 | offset = to - kaddr; | |
304 | buf += copy; | |
305 | kunmap_atomic(kaddr); | |
306 | copy = min(bytes, iov->iov_len - skip); | |
307 | } | |
308 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 309 | |
f0d1bec9 AV |
310 | kaddr = kmap(page); |
311 | to = kaddr + offset; | |
09fc68dc | 312 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
313 | copy -= left; |
314 | skip += copy; | |
315 | to += copy; | |
316 | bytes -= copy; | |
317 | while (unlikely(!left && bytes)) { | |
318 | iov++; | |
319 | buf = iov->iov_base; | |
320 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 321 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
322 | copy -= left; |
323 | skip = copy; | |
324 | to += copy; | |
325 | bytes -= copy; | |
326 | } | |
327 | kunmap(page); | |
3fa6c507 | 328 | |
f0d1bec9 | 329 | done: |
81055e58 AV |
330 | if (skip == iov->iov_len) { |
331 | iov++; | |
332 | skip = 0; | |
333 | } | |
f0d1bec9 AV |
334 | i->count -= wanted - bytes; |
335 | i->nr_segs -= iov - i->iov; | |
336 | i->iov = iov; | |
337 | i->iov_offset = skip; | |
338 | return wanted - bytes; | |
339 | } | |
f0d1bec9 | 340 | |
241699cd AV |
341 | #ifdef PIPE_PARANOIA |
342 | static bool sanity(const struct iov_iter *i) | |
343 | { | |
344 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
345 | unsigned int p_head = pipe->head; |
346 | unsigned int p_tail = pipe->tail; | |
347 | unsigned int p_mask = pipe->ring_size - 1; | |
348 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); | |
349 | unsigned int i_head = i->head; | |
350 | unsigned int idx; | |
351 | ||
241699cd AV |
352 | if (i->iov_offset) { |
353 | struct pipe_buffer *p; | |
8cefc107 | 354 | if (unlikely(p_occupancy == 0)) |
241699cd | 355 | goto Bad; // pipe must be non-empty |
8cefc107 | 356 | if (unlikely(i_head != p_head - 1)) |
241699cd AV |
357 | goto Bad; // must be at the last buffer... |
358 | ||
8cefc107 | 359 | p = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
360 | if (unlikely(p->offset + p->len != i->iov_offset)) |
361 | goto Bad; // ... at the end of segment | |
362 | } else { | |
8cefc107 | 363 | if (i_head != p_head) |
241699cd AV |
364 | goto Bad; // must be right after the last buffer |
365 | } | |
366 | return true; | |
367 | Bad: | |
8cefc107 DH |
368 | printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); |
369 | printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", | |
370 | p_head, p_tail, pipe->ring_size); | |
371 | for (idx = 0; idx < pipe->ring_size; idx++) | |
241699cd AV |
372 | printk(KERN_ERR "[%p %p %d %d]\n", |
373 | pipe->bufs[idx].ops, | |
374 | pipe->bufs[idx].page, | |
375 | pipe->bufs[idx].offset, | |
376 | pipe->bufs[idx].len); | |
377 | WARN_ON(1); | |
378 | return false; | |
379 | } | |
380 | #else | |
381 | #define sanity(i) true | |
382 | #endif | |
383 | ||
241699cd AV |
384 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
385 | struct iov_iter *i) | |
386 | { | |
387 | struct pipe_inode_info *pipe = i->pipe; | |
388 | struct pipe_buffer *buf; | |
8cefc107 DH |
389 | unsigned int p_tail = pipe->tail; |
390 | unsigned int p_mask = pipe->ring_size - 1; | |
391 | unsigned int i_head = i->head; | |
241699cd | 392 | size_t off; |
241699cd AV |
393 | |
394 | if (unlikely(bytes > i->count)) | |
395 | bytes = i->count; | |
396 | ||
397 | if (unlikely(!bytes)) | |
398 | return 0; | |
399 | ||
400 | if (!sanity(i)) | |
401 | return 0; | |
402 | ||
403 | off = i->iov_offset; | |
8cefc107 | 404 | buf = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
405 | if (off) { |
406 | if (offset == off && buf->page == page) { | |
407 | /* merge with the last one */ | |
408 | buf->len += bytes; | |
409 | i->iov_offset += bytes; | |
410 | goto out; | |
411 | } | |
8cefc107 DH |
412 | i_head++; |
413 | buf = &pipe->bufs[i_head & p_mask]; | |
241699cd | 414 | } |
6718b6f8 | 415 | if (pipe_full(i_head, p_tail, pipe->max_usage)) |
241699cd | 416 | return 0; |
8cefc107 | 417 | |
241699cd | 418 | buf->ops = &page_cache_pipe_buf_ops; |
8cefc107 DH |
419 | get_page(page); |
420 | buf->page = page; | |
241699cd AV |
421 | buf->offset = offset; |
422 | buf->len = bytes; | |
8cefc107 DH |
423 | |
424 | pipe->head = i_head + 1; | |
241699cd | 425 | i->iov_offset = offset + bytes; |
8cefc107 | 426 | i->head = i_head; |
241699cd AV |
427 | out: |
428 | i->count -= bytes; | |
429 | return bytes; | |
430 | } | |
431 | ||
171a0203 AA |
432 | /* |
433 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of | |
434 | * bytes. For each iovec, fault in each page that constitutes the iovec. | |
435 | * | |
436 | * Return 0 on success, or non-zero if the memory could not be accessed (i.e. | |
437 | * because it is an invalid address). | |
438 | */ | |
8409a0d2 | 439 | int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) |
171a0203 | 440 | { |
0e8f0d67 | 441 | if (iter_is_iovec(i)) { |
8409a0d2 AV |
442 | const struct iovec *p; |
443 | size_t skip; | |
444 | ||
445 | if (bytes > i->count) | |
446 | bytes = i->count; | |
447 | for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { | |
448 | size_t len = min(bytes, p->iov_len - skip); | |
449 | int err; | |
450 | ||
451 | if (unlikely(!len)) | |
452 | continue; | |
453 | err = fault_in_pages_readable(p->iov_base + skip, len); | |
171a0203 | 454 | if (unlikely(err)) |
8409a0d2 AV |
455 | return err; |
456 | bytes -= len; | |
457 | } | |
171a0203 AA |
458 | } |
459 | return 0; | |
460 | } | |
d4690f1e | 461 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
171a0203 | 462 | |
aa563d7b | 463 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
464 | const struct iovec *iov, unsigned long nr_segs, |
465 | size_t count) | |
466 | { | |
aa563d7b | 467 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
468 | *i = (struct iov_iter) { |
469 | .iter_type = ITER_IOVEC, | |
470 | .data_source = direction, | |
471 | .iov = iov, | |
472 | .nr_segs = nr_segs, | |
473 | .iov_offset = 0, | |
474 | .count = count | |
475 | }; | |
71d8e532 AV |
476 | } |
477 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 478 | |
241699cd AV |
479 | static inline bool allocated(struct pipe_buffer *buf) |
480 | { | |
481 | return buf->ops == &default_pipe_buf_ops; | |
482 | } | |
483 | ||
8cefc107 DH |
484 | static inline void data_start(const struct iov_iter *i, |
485 | unsigned int *iter_headp, size_t *offp) | |
241699cd | 486 | { |
8cefc107 DH |
487 | unsigned int p_mask = i->pipe->ring_size - 1; |
488 | unsigned int iter_head = i->head; | |
241699cd | 489 | size_t off = i->iov_offset; |
8cefc107 DH |
490 | |
491 | if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || | |
492 | off == PAGE_SIZE)) { | |
493 | iter_head++; | |
241699cd AV |
494 | off = 0; |
495 | } | |
8cefc107 | 496 | *iter_headp = iter_head; |
241699cd AV |
497 | *offp = off; |
498 | } | |
499 | ||
500 | static size_t push_pipe(struct iov_iter *i, size_t size, | |
8cefc107 | 501 | int *iter_headp, size_t *offp) |
241699cd AV |
502 | { |
503 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
504 | unsigned int p_tail = pipe->tail; |
505 | unsigned int p_mask = pipe->ring_size - 1; | |
506 | unsigned int iter_head; | |
241699cd | 507 | size_t off; |
241699cd AV |
508 | ssize_t left; |
509 | ||
510 | if (unlikely(size > i->count)) | |
511 | size = i->count; | |
512 | if (unlikely(!size)) | |
513 | return 0; | |
514 | ||
515 | left = size; | |
8cefc107 DH |
516 | data_start(i, &iter_head, &off); |
517 | *iter_headp = iter_head; | |
241699cd AV |
518 | *offp = off; |
519 | if (off) { | |
520 | left -= PAGE_SIZE - off; | |
521 | if (left <= 0) { | |
8cefc107 | 522 | pipe->bufs[iter_head & p_mask].len += size; |
241699cd AV |
523 | return size; |
524 | } | |
8cefc107 DH |
525 | pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; |
526 | iter_head++; | |
241699cd | 527 | } |
6718b6f8 | 528 | while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { |
8cefc107 | 529 | struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; |
241699cd AV |
530 | struct page *page = alloc_page(GFP_USER); |
531 | if (!page) | |
532 | break; | |
8cefc107 DH |
533 | |
534 | buf->ops = &default_pipe_buf_ops; | |
535 | buf->page = page; | |
536 | buf->offset = 0; | |
537 | buf->len = min_t(ssize_t, left, PAGE_SIZE); | |
538 | left -= buf->len; | |
539 | iter_head++; | |
540 | pipe->head = iter_head; | |
541 | ||
542 | if (left == 0) | |
241699cd | 543 | return size; |
241699cd AV |
544 | } |
545 | return size - left; | |
546 | } | |
547 | ||
548 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, | |
549 | struct iov_iter *i) | |
550 | { | |
551 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
552 | unsigned int p_mask = pipe->ring_size - 1; |
553 | unsigned int i_head; | |
241699cd | 554 | size_t n, off; |
241699cd AV |
555 | |
556 | if (!sanity(i)) | |
557 | return 0; | |
558 | ||
8cefc107 | 559 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
560 | if (unlikely(!n)) |
561 | return 0; | |
8cefc107 | 562 | do { |
241699cd | 563 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
564 | memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); |
565 | i->head = i_head; | |
241699cd AV |
566 | i->iov_offset = off + chunk; |
567 | n -= chunk; | |
568 | addr += chunk; | |
8cefc107 DH |
569 | off = 0; |
570 | i_head++; | |
571 | } while (n); | |
241699cd AV |
572 | i->count -= bytes; |
573 | return bytes; | |
574 | } | |
575 | ||
f9152895 AV |
576 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
577 | __wsum sum, size_t off) | |
578 | { | |
cc44c17b | 579 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
f9152895 AV |
580 | return csum_block_add(sum, next, off); |
581 | } | |
582 | ||
78e1f386 | 583 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
6852df12 | 584 | struct iov_iter *i, __wsum *sump) |
78e1f386 AV |
585 | { |
586 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 | 587 | unsigned int p_mask = pipe->ring_size - 1; |
6852df12 AV |
588 | __wsum sum = *sump; |
589 | size_t off = 0; | |
8cefc107 | 590 | unsigned int i_head; |
6852df12 | 591 | size_t r; |
78e1f386 AV |
592 | |
593 | if (!sanity(i)) | |
594 | return 0; | |
595 | ||
6852df12 AV |
596 | bytes = push_pipe(i, bytes, &i_head, &r); |
597 | while (bytes) { | |
598 | size_t chunk = min_t(size_t, bytes, PAGE_SIZE - r); | |
2495bdcc | 599 | char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page); |
6852df12 | 600 | sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off); |
2495bdcc | 601 | kunmap_local(p); |
8cefc107 | 602 | i->head = i_head; |
78e1f386 | 603 | i->iov_offset = r + chunk; |
6852df12 | 604 | bytes -= chunk; |
78e1f386 | 605 | off += chunk; |
8cefc107 DH |
606 | r = 0; |
607 | i_head++; | |
6852df12 AV |
608 | } |
609 | *sump = sum; | |
610 | i->count -= off; | |
611 | return off; | |
78e1f386 AV |
612 | } |
613 | ||
aa28de27 | 614 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 615 | { |
00e23707 | 616 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 617 | return copy_pipe_to_iter(addr, bytes, i); |
09fc68dc AV |
618 | if (iter_is_iovec(i)) |
619 | might_fault(); | |
7baa5099 AV |
620 | iterate_and_advance(i, bytes, base, len, off, |
621 | copyout(base, addr + off, len), | |
622 | memcpy(base, addr + off, len) | |
3d4d3e48 | 623 | ) |
62a8067a | 624 | |
3d4d3e48 | 625 | return bytes; |
c35e0248 | 626 | } |
aa28de27 | 627 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 628 | |
ec6347bb DW |
629 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
630 | static int copyout_mc(void __user *to, const void *from, size_t n) | |
8780356e | 631 | { |
96d4f267 | 632 | if (access_ok(to, n)) { |
d0ef4c36 | 633 | instrument_copy_to_user(to, from, n); |
ec6347bb | 634 | n = copy_mc_to_user((__force void *) to, from, n); |
8780356e DW |
635 | } |
636 | return n; | |
637 | } | |
638 | ||
ec6347bb | 639 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
ca146f6f DW |
640 | struct iov_iter *i) |
641 | { | |
642 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
643 | unsigned int p_mask = pipe->ring_size - 1; |
644 | unsigned int i_head; | |
ca146f6f | 645 | size_t n, off, xfer = 0; |
ca146f6f DW |
646 | |
647 | if (!sanity(i)) | |
648 | return 0; | |
649 | ||
2a510a74 AV |
650 | n = push_pipe(i, bytes, &i_head, &off); |
651 | while (n) { | |
ca146f6f | 652 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
2a510a74 | 653 | char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page); |
ca146f6f | 654 | unsigned long rem; |
2a510a74 AV |
655 | rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); |
656 | chunk -= rem; | |
657 | kunmap_local(p); | |
8cefc107 | 658 | i->head = i_head; |
2a510a74 AV |
659 | i->iov_offset = off + chunk; |
660 | xfer += chunk; | |
ca146f6f DW |
661 | if (rem) |
662 | break; | |
663 | n -= chunk; | |
8cefc107 DH |
664 | off = 0; |
665 | i_head++; | |
2a510a74 | 666 | } |
ca146f6f DW |
667 | i->count -= xfer; |
668 | return xfer; | |
669 | } | |
670 | ||
bf3eeb9b | 671 | /** |
ec6347bb | 672 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
bf3eeb9b DW |
673 | * @addr: source kernel address |
674 | * @bytes: total transfer length | |
44e55997 | 675 | * @i: destination iterator |
bf3eeb9b | 676 | * |
ec6347bb DW |
677 | * The pmem driver deploys this for the dax operation |
678 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the | |
679 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes | |
680 | * successfully copied. | |
bf3eeb9b | 681 | * |
ec6347bb | 682 | * The main differences between this and typical _copy_to_iter(). |
bf3eeb9b DW |
683 | * |
684 | * * Typical tail/residue handling after a fault retries the copy | |
685 | * byte-by-byte until the fault happens again. Re-triggering machine | |
686 | * checks is potentially fatal so the implementation uses source | |
687 | * alignment and poison alignment assumptions to avoid re-triggering | |
688 | * hardware exceptions. | |
689 | * | |
690 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. | |
691 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return | |
692 | * a short copy. | |
44e55997 RD |
693 | * |
694 | * Return: number of bytes copied (may be %0) | |
bf3eeb9b | 695 | */ |
ec6347bb | 696 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
8780356e | 697 | { |
00e23707 | 698 | if (unlikely(iov_iter_is_pipe(i))) |
ec6347bb | 699 | return copy_mc_pipe_to_iter(addr, bytes, i); |
8780356e DW |
700 | if (iter_is_iovec(i)) |
701 | might_fault(); | |
7baa5099 AV |
702 | __iterate_and_advance(i, bytes, base, len, off, |
703 | copyout_mc(base, addr + off, len), | |
704 | copy_mc_to_kernel(base, addr + off, len) | |
8780356e DW |
705 | ) |
706 | ||
707 | return bytes; | |
708 | } | |
ec6347bb DW |
709 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
710 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 711 | |
aa28de27 | 712 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 713 | { |
00e23707 | 714 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
715 | WARN_ON(1); |
716 | return 0; | |
717 | } | |
09fc68dc AV |
718 | if (iter_is_iovec(i)) |
719 | might_fault(); | |
7baa5099 AV |
720 | iterate_and_advance(i, bytes, base, len, off, |
721 | copyin(addr + off, base, len), | |
722 | memcpy(addr + off, base, len) | |
0dbca9a4 AV |
723 | ) |
724 | ||
725 | return bytes; | |
c35e0248 | 726 | } |
aa28de27 | 727 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 728 | |
aa28de27 | 729 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 | 730 | { |
00e23707 | 731 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
732 | WARN_ON(1); |
733 | return 0; | |
734 | } | |
7baa5099 AV |
735 | iterate_and_advance(i, bytes, base, len, off, |
736 | __copy_from_user_inatomic_nocache(addr + off, base, len), | |
737 | memcpy(addr + off, base, len) | |
aa583096 AV |
738 | ) |
739 | ||
740 | return bytes; | |
741 | } | |
aa28de27 | 742 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 743 | |
0aed55af | 744 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
745 | /** |
746 | * _copy_from_iter_flushcache - write destination through cpu cache | |
747 | * @addr: destination kernel address | |
748 | * @bytes: total transfer length | |
44e55997 | 749 | * @i: source iterator |
abd08d7d DW |
750 | * |
751 | * The pmem driver arranges for filesystem-dax to use this facility via | |
752 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
753 | * are flushed through the CPU cache. It is differentiated from | |
754 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
755 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
756 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
757 | * instructions that strand dirty-data in the cache. | |
44e55997 RD |
758 | * |
759 | * Return: number of bytes copied (may be %0) | |
abd08d7d | 760 | */ |
6a37e940 | 761 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af | 762 | { |
00e23707 | 763 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
764 | WARN_ON(1); |
765 | return 0; | |
766 | } | |
7baa5099 AV |
767 | iterate_and_advance(i, bytes, base, len, off, |
768 | __copy_from_user_flushcache(addr + off, base, len), | |
769 | memcpy_flushcache(addr + off, base, len) | |
0aed55af DW |
770 | ) |
771 | ||
772 | return bytes; | |
773 | } | |
6a37e940 | 774 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
775 | #endif |
776 | ||
72e809ed AV |
777 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
778 | { | |
6daef95b ED |
779 | struct page *head; |
780 | size_t v = n + offset; | |
781 | ||
782 | /* | |
783 | * The general case needs to access the page order in order | |
784 | * to compute the page size. | |
785 | * However, we mostly deal with order-0 pages and thus can | |
786 | * avoid a possible cache line miss for requests that fit all | |
787 | * page orders. | |
788 | */ | |
789 | if (n <= v && v <= PAGE_SIZE) | |
790 | return true; | |
791 | ||
792 | head = compound_head(page); | |
793 | v += (page - head) << PAGE_SHIFT; | |
a90bcb86 | 794 | |
a50b854e | 795 | if (likely(n <= v && v <= (page_size(head)))) |
72e809ed AV |
796 | return true; |
797 | WARN_ON(1); | |
798 | return false; | |
799 | } | |
cbbd26b8 | 800 | |
08aa6479 | 801 | static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
62a8067a AV |
802 | struct iov_iter *i) |
803 | { | |
28f38db7 AV |
804 | if (likely(iter_is_iovec(i))) |
805 | return copy_page_to_iter_iovec(page, offset, bytes, i); | |
806 | if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { | |
c1d4d6a9 AV |
807 | void *kaddr = kmap_local_page(page); |
808 | size_t wanted = _copy_to_iter(kaddr + offset, bytes, i); | |
809 | kunmap_local(kaddr); | |
d271524a | 810 | return wanted; |
28f38db7 AV |
811 | } |
812 | if (iov_iter_is_pipe(i)) | |
813 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
814 | if (unlikely(iov_iter_is_discard(i))) { | |
a506abc7 AV |
815 | if (unlikely(i->count < bytes)) |
816 | bytes = i->count; | |
817 | i->count -= bytes; | |
9ea9ce04 | 818 | return bytes; |
28f38db7 AV |
819 | } |
820 | WARN_ON(1); | |
821 | return 0; | |
62a8067a | 822 | } |
08aa6479 AV |
823 | |
824 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, | |
825 | struct iov_iter *i) | |
826 | { | |
827 | size_t res = 0; | |
828 | if (unlikely(!page_copy_sane(page, offset, bytes))) | |
829 | return 0; | |
830 | page += offset / PAGE_SIZE; // first subpage | |
831 | offset %= PAGE_SIZE; | |
832 | while (1) { | |
833 | size_t n = __copy_page_to_iter(page, offset, | |
834 | min(bytes, (size_t)PAGE_SIZE - offset), i); | |
835 | res += n; | |
836 | bytes -= n; | |
837 | if (!bytes || !n) | |
838 | break; | |
839 | offset += n; | |
840 | if (offset == PAGE_SIZE) { | |
841 | page++; | |
842 | offset = 0; | |
843 | } | |
844 | } | |
845 | return res; | |
846 | } | |
62a8067a AV |
847 | EXPORT_SYMBOL(copy_page_to_iter); |
848 | ||
849 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
850 | struct iov_iter *i) | |
851 | { | |
72e809ed AV |
852 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
853 | return 0; | |
28f38db7 AV |
854 | if (likely(iter_is_iovec(i))) |
855 | return copy_page_from_iter_iovec(page, offset, bytes, i); | |
856 | if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { | |
55ca375c | 857 | void *kaddr = kmap_local_page(page); |
aa28de27 | 858 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
55ca375c | 859 | kunmap_local(kaddr); |
d271524a | 860 | return wanted; |
28f38db7 AV |
861 | } |
862 | WARN_ON(1); | |
863 | return 0; | |
62a8067a AV |
864 | } |
865 | EXPORT_SYMBOL(copy_page_from_iter); | |
866 | ||
241699cd AV |
867 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
868 | { | |
869 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
870 | unsigned int p_mask = pipe->ring_size - 1; |
871 | unsigned int i_head; | |
241699cd | 872 | size_t n, off; |
241699cd AV |
873 | |
874 | if (!sanity(i)) | |
875 | return 0; | |
876 | ||
8cefc107 | 877 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
878 | if (unlikely(!n)) |
879 | return 0; | |
880 | ||
8cefc107 | 881 | do { |
241699cd | 882 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
893839fd AV |
883 | char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page); |
884 | memset(p + off, 0, chunk); | |
885 | kunmap_local(p); | |
8cefc107 | 886 | i->head = i_head; |
241699cd AV |
887 | i->iov_offset = off + chunk; |
888 | n -= chunk; | |
8cefc107 DH |
889 | off = 0; |
890 | i_head++; | |
891 | } while (n); | |
241699cd AV |
892 | i->count -= bytes; |
893 | return bytes; | |
894 | } | |
895 | ||
c35e0248 MW |
896 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
897 | { | |
00e23707 | 898 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 899 | return pipe_zero(bytes, i); |
7baa5099 AV |
900 | iterate_and_advance(i, bytes, base, len, count, |
901 | clear_user(base, len), | |
902 | memset(base, 0, len) | |
8442fa46 AV |
903 | ) |
904 | ||
905 | return bytes; | |
c35e0248 MW |
906 | } |
907 | EXPORT_SYMBOL(iov_iter_zero); | |
908 | ||
f0b65f39 AV |
909 | size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, |
910 | struct iov_iter *i) | |
62a8067a | 911 | { |
04a31165 | 912 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
913 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
914 | kunmap_atomic(kaddr); | |
915 | return 0; | |
916 | } | |
9ea9ce04 | 917 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
918 | kunmap_atomic(kaddr); |
919 | WARN_ON(1); | |
920 | return 0; | |
921 | } | |
7baa5099 AV |
922 | iterate_and_advance(i, bytes, base, len, off, |
923 | copyin(p + off, base, len), | |
924 | memcpy(p + off, base, len) | |
04a31165 AV |
925 | ) |
926 | kunmap_atomic(kaddr); | |
927 | return bytes; | |
62a8067a | 928 | } |
f0b65f39 | 929 | EXPORT_SYMBOL(copy_page_from_iter_atomic); |
62a8067a | 930 | |
b9dc6f65 AV |
931 | static inline void pipe_truncate(struct iov_iter *i) |
932 | { | |
933 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
934 | unsigned int p_tail = pipe->tail; |
935 | unsigned int p_head = pipe->head; | |
936 | unsigned int p_mask = pipe->ring_size - 1; | |
937 | ||
938 | if (!pipe_empty(p_head, p_tail)) { | |
939 | struct pipe_buffer *buf; | |
940 | unsigned int i_head = i->head; | |
b9dc6f65 | 941 | size_t off = i->iov_offset; |
8cefc107 | 942 | |
b9dc6f65 | 943 | if (off) { |
8cefc107 DH |
944 | buf = &pipe->bufs[i_head & p_mask]; |
945 | buf->len = off - buf->offset; | |
946 | i_head++; | |
b9dc6f65 | 947 | } |
8cefc107 DH |
948 | while (p_head != i_head) { |
949 | p_head--; | |
950 | pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); | |
b9dc6f65 | 951 | } |
8cefc107 DH |
952 | |
953 | pipe->head = p_head; | |
b9dc6f65 AV |
954 | } |
955 | } | |
956 | ||
241699cd AV |
957 | static void pipe_advance(struct iov_iter *i, size_t size) |
958 | { | |
959 | struct pipe_inode_info *pipe = i->pipe; | |
241699cd | 960 | if (size) { |
b9dc6f65 | 961 | struct pipe_buffer *buf; |
8cefc107 DH |
962 | unsigned int p_mask = pipe->ring_size - 1; |
963 | unsigned int i_head = i->head; | |
b9dc6f65 | 964 | size_t off = i->iov_offset, left = size; |
8cefc107 | 965 | |
241699cd | 966 | if (off) /* make it relative to the beginning of buffer */ |
8cefc107 | 967 | left += off - pipe->bufs[i_head & p_mask].offset; |
241699cd | 968 | while (1) { |
8cefc107 | 969 | buf = &pipe->bufs[i_head & p_mask]; |
b9dc6f65 | 970 | if (left <= buf->len) |
241699cd | 971 | break; |
b9dc6f65 | 972 | left -= buf->len; |
8cefc107 | 973 | i_head++; |
241699cd | 974 | } |
8cefc107 | 975 | i->head = i_head; |
b9dc6f65 | 976 | i->iov_offset = buf->offset + left; |
241699cd | 977 | } |
b9dc6f65 AV |
978 | i->count -= size; |
979 | /* ... and discard everything past that point */ | |
980 | pipe_truncate(i); | |
241699cd AV |
981 | } |
982 | ||
54c8195b PB |
983 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
984 | { | |
985 | struct bvec_iter bi; | |
986 | ||
987 | bi.bi_size = i->count; | |
988 | bi.bi_bvec_done = i->iov_offset; | |
989 | bi.bi_idx = 0; | |
990 | bvec_iter_advance(i->bvec, &bi, size); | |
991 | ||
992 | i->bvec += bi.bi_idx; | |
993 | i->nr_segs -= bi.bi_idx; | |
994 | i->count = bi.bi_size; | |
995 | i->iov_offset = bi.bi_bvec_done; | |
996 | } | |
997 | ||
185ac4d4 AV |
998 | static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) |
999 | { | |
1000 | const struct iovec *iov, *end; | |
1001 | ||
1002 | if (!i->count) | |
1003 | return; | |
1004 | i->count -= size; | |
1005 | ||
1006 | size += i->iov_offset; // from beginning of current segment | |
1007 | for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { | |
1008 | if (likely(size < iov->iov_len)) | |
1009 | break; | |
1010 | size -= iov->iov_len; | |
1011 | } | |
1012 | i->iov_offset = size; | |
1013 | i->nr_segs -= iov - i->iov; | |
1014 | i->iov = iov; | |
1015 | } | |
1016 | ||
62a8067a AV |
1017 | void iov_iter_advance(struct iov_iter *i, size_t size) |
1018 | { | |
3b3fc051 AV |
1019 | if (unlikely(i->count < size)) |
1020 | size = i->count; | |
185ac4d4 AV |
1021 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { |
1022 | /* iovec and kvec have identical layouts */ | |
1023 | iov_iter_iovec_advance(i, size); | |
1024 | } else if (iov_iter_is_bvec(i)) { | |
1025 | iov_iter_bvec_advance(i, size); | |
1026 | } else if (iov_iter_is_pipe(i)) { | |
241699cd | 1027 | pipe_advance(i, size); |
185ac4d4 | 1028 | } else if (unlikely(iov_iter_is_xarray(i))) { |
7ff50620 DH |
1029 | i->iov_offset += size; |
1030 | i->count -= size; | |
185ac4d4 AV |
1031 | } else if (iov_iter_is_discard(i)) { |
1032 | i->count -= size; | |
54c8195b | 1033 | } |
62a8067a AV |
1034 | } |
1035 | EXPORT_SYMBOL(iov_iter_advance); | |
1036 | ||
27c0e374 AV |
1037 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
1038 | { | |
1039 | if (!unroll) | |
1040 | return; | |
5b47d59a AV |
1041 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
1042 | return; | |
27c0e374 | 1043 | i->count += unroll; |
00e23707 | 1044 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 | 1045 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 DH |
1046 | unsigned int p_mask = pipe->ring_size - 1; |
1047 | unsigned int i_head = i->head; | |
27c0e374 AV |
1048 | size_t off = i->iov_offset; |
1049 | while (1) { | |
8cefc107 DH |
1050 | struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; |
1051 | size_t n = off - b->offset; | |
27c0e374 | 1052 | if (unroll < n) { |
4fa55cef | 1053 | off -= unroll; |
27c0e374 AV |
1054 | break; |
1055 | } | |
1056 | unroll -= n; | |
8cefc107 | 1057 | if (!unroll && i_head == i->start_head) { |
27c0e374 AV |
1058 | off = 0; |
1059 | break; | |
1060 | } | |
8cefc107 DH |
1061 | i_head--; |
1062 | b = &pipe->bufs[i_head & p_mask]; | |
1063 | off = b->offset + b->len; | |
27c0e374 AV |
1064 | } |
1065 | i->iov_offset = off; | |
8cefc107 | 1066 | i->head = i_head; |
27c0e374 AV |
1067 | pipe_truncate(i); |
1068 | return; | |
1069 | } | |
9ea9ce04 DH |
1070 | if (unlikely(iov_iter_is_discard(i))) |
1071 | return; | |
27c0e374 AV |
1072 | if (unroll <= i->iov_offset) { |
1073 | i->iov_offset -= unroll; | |
1074 | return; | |
1075 | } | |
1076 | unroll -= i->iov_offset; | |
7ff50620 DH |
1077 | if (iov_iter_is_xarray(i)) { |
1078 | BUG(); /* We should never go beyond the start of the specified | |
1079 | * range since we might then be straying into pages that | |
1080 | * aren't pinned. | |
1081 | */ | |
1082 | } else if (iov_iter_is_bvec(i)) { | |
27c0e374 AV |
1083 | const struct bio_vec *bvec = i->bvec; |
1084 | while (1) { | |
1085 | size_t n = (--bvec)->bv_len; | |
1086 | i->nr_segs++; | |
1087 | if (unroll <= n) { | |
1088 | i->bvec = bvec; | |
1089 | i->iov_offset = n - unroll; | |
1090 | return; | |
1091 | } | |
1092 | unroll -= n; | |
1093 | } | |
1094 | } else { /* same logics for iovec and kvec */ | |
1095 | const struct iovec *iov = i->iov; | |
1096 | while (1) { | |
1097 | size_t n = (--iov)->iov_len; | |
1098 | i->nr_segs++; | |
1099 | if (unroll <= n) { | |
1100 | i->iov = iov; | |
1101 | i->iov_offset = n - unroll; | |
1102 | return; | |
1103 | } | |
1104 | unroll -= n; | |
1105 | } | |
1106 | } | |
1107 | } | |
1108 | EXPORT_SYMBOL(iov_iter_revert); | |
1109 | ||
62a8067a AV |
1110 | /* |
1111 | * Return the count of just the current iov_iter segment. | |
1112 | */ | |
1113 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
1114 | { | |
28f38db7 AV |
1115 | if (i->nr_segs > 1) { |
1116 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1117 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
1118 | if (iov_iter_is_bvec(i)) | |
1119 | return min(i->count, i->bvec->bv_len - i->iov_offset); | |
1120 | } | |
1121 | return i->count; | |
62a8067a AV |
1122 | } |
1123 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
1124 | ||
aa563d7b | 1125 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 1126 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
1127 | size_t count) |
1128 | { | |
aa563d7b | 1129 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
1130 | *i = (struct iov_iter){ |
1131 | .iter_type = ITER_KVEC, | |
1132 | .data_source = direction, | |
1133 | .kvec = kvec, | |
1134 | .nr_segs = nr_segs, | |
1135 | .iov_offset = 0, | |
1136 | .count = count | |
1137 | }; | |
abb78f87 AV |
1138 | } |
1139 | EXPORT_SYMBOL(iov_iter_kvec); | |
1140 | ||
aa563d7b | 1141 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1142 | const struct bio_vec *bvec, unsigned long nr_segs, |
1143 | size_t count) | |
1144 | { | |
aa563d7b | 1145 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
1146 | *i = (struct iov_iter){ |
1147 | .iter_type = ITER_BVEC, | |
1148 | .data_source = direction, | |
1149 | .bvec = bvec, | |
1150 | .nr_segs = nr_segs, | |
1151 | .iov_offset = 0, | |
1152 | .count = count | |
1153 | }; | |
05afcb77 AV |
1154 | } |
1155 | EXPORT_SYMBOL(iov_iter_bvec); | |
1156 | ||
aa563d7b | 1157 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1158 | struct pipe_inode_info *pipe, |
1159 | size_t count) | |
1160 | { | |
aa563d7b | 1161 | BUG_ON(direction != READ); |
8cefc107 | 1162 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
8cd54c1c AV |
1163 | *i = (struct iov_iter){ |
1164 | .iter_type = ITER_PIPE, | |
1165 | .data_source = false, | |
1166 | .pipe = pipe, | |
1167 | .head = pipe->head, | |
1168 | .start_head = pipe->head, | |
1169 | .iov_offset = 0, | |
1170 | .count = count | |
1171 | }; | |
241699cd AV |
1172 | } |
1173 | EXPORT_SYMBOL(iov_iter_pipe); | |
1174 | ||
7ff50620 DH |
1175 | /** |
1176 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray | |
1177 | * @i: The iterator to initialise. | |
1178 | * @direction: The direction of the transfer. | |
1179 | * @xarray: The xarray to access. | |
1180 | * @start: The start file position. | |
1181 | * @count: The size of the I/O buffer in bytes. | |
1182 | * | |
1183 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
1184 | * inode or to inject data into those pages. The pages *must* be prevented | |
1185 | * from evaporation, either by taking a ref on them or locking them by the | |
1186 | * caller. | |
1187 | */ | |
1188 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, | |
1189 | struct xarray *xarray, loff_t start, size_t count) | |
1190 | { | |
1191 | BUG_ON(direction & ~1); | |
8cd54c1c AV |
1192 | *i = (struct iov_iter) { |
1193 | .iter_type = ITER_XARRAY, | |
1194 | .data_source = direction, | |
1195 | .xarray = xarray, | |
1196 | .xarray_start = start, | |
1197 | .count = count, | |
1198 | .iov_offset = 0 | |
1199 | }; | |
7ff50620 DH |
1200 | } |
1201 | EXPORT_SYMBOL(iov_iter_xarray); | |
1202 | ||
9ea9ce04 DH |
1203 | /** |
1204 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
1205 | * @i: The iterator to initialise. | |
1206 | * @direction: The direction of the transfer. | |
1207 | * @count: The size of the I/O buffer in bytes. | |
1208 | * | |
1209 | * Set up an I/O iterator that just discards everything that's written to it. | |
1210 | * It's only available as a READ iterator. | |
1211 | */ | |
1212 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
1213 | { | |
1214 | BUG_ON(direction != READ); | |
8cd54c1c AV |
1215 | *i = (struct iov_iter){ |
1216 | .iter_type = ITER_DISCARD, | |
1217 | .data_source = false, | |
1218 | .count = count, | |
1219 | .iov_offset = 0 | |
1220 | }; | |
9ea9ce04 DH |
1221 | } |
1222 | EXPORT_SYMBOL(iov_iter_discard); | |
1223 | ||
9221d2e3 | 1224 | static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) |
62a8067a | 1225 | { |
04a31165 AV |
1226 | unsigned long res = 0; |
1227 | size_t size = i->count; | |
9221d2e3 AV |
1228 | size_t skip = i->iov_offset; |
1229 | unsigned k; | |
1230 | ||
1231 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1232 | size_t len = i->iov[k].iov_len - skip; | |
1233 | if (len) { | |
1234 | res |= (unsigned long)i->iov[k].iov_base + skip; | |
1235 | if (len > size) | |
1236 | len = size; | |
1237 | res |= len; | |
1238 | size -= len; | |
1239 | if (!size) | |
1240 | break; | |
1241 | } | |
1242 | } | |
1243 | return res; | |
1244 | } | |
04a31165 | 1245 | |
9221d2e3 AV |
1246 | static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) |
1247 | { | |
1248 | unsigned res = 0; | |
1249 | size_t size = i->count; | |
1250 | unsigned skip = i->iov_offset; | |
1251 | unsigned k; | |
1252 | ||
1253 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1254 | size_t len = i->bvec[k].bv_len - skip; | |
1255 | res |= (unsigned long)i->bvec[k].bv_offset + skip; | |
1256 | if (len > size) | |
1257 | len = size; | |
1258 | res |= len; | |
1259 | size -= len; | |
1260 | if (!size) | |
1261 | break; | |
1262 | } | |
1263 | return res; | |
1264 | } | |
1265 | ||
1266 | unsigned long iov_iter_alignment(const struct iov_iter *i) | |
1267 | { | |
1268 | /* iovec and kvec have identical layouts */ | |
1269 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1270 | return iov_iter_alignment_iovec(i); | |
1271 | ||
1272 | if (iov_iter_is_bvec(i)) | |
1273 | return iov_iter_alignment_bvec(i); | |
1274 | ||
1275 | if (iov_iter_is_pipe(i)) { | |
e0ff126e | 1276 | unsigned int p_mask = i->pipe->ring_size - 1; |
9221d2e3 | 1277 | size_t size = i->count; |
e0ff126e | 1278 | |
8cefc107 | 1279 | if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) |
241699cd AV |
1280 | return size | i->iov_offset; |
1281 | return size; | |
1282 | } | |
9221d2e3 AV |
1283 | |
1284 | if (iov_iter_is_xarray(i)) | |
3d14ec1f | 1285 | return (i->xarray_start + i->iov_offset) | i->count; |
9221d2e3 AV |
1286 | |
1287 | return 0; | |
62a8067a AV |
1288 | } |
1289 | EXPORT_SYMBOL(iov_iter_alignment); | |
1290 | ||
357f435d AV |
1291 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1292 | { | |
33844e66 | 1293 | unsigned long res = 0; |
610c7a71 | 1294 | unsigned long v = 0; |
357f435d | 1295 | size_t size = i->count; |
610c7a71 | 1296 | unsigned k; |
357f435d | 1297 | |
610c7a71 | 1298 | if (WARN_ON(!iter_is_iovec(i))) |
241699cd | 1299 | return ~0U; |
241699cd | 1300 | |
610c7a71 AV |
1301 | for (k = 0; k < i->nr_segs; k++) { |
1302 | if (i->iov[k].iov_len) { | |
1303 | unsigned long base = (unsigned long)i->iov[k].iov_base; | |
1304 | if (v) // if not the first one | |
1305 | res |= base | v; // this start | previous end | |
1306 | v = base + i->iov[k].iov_len; | |
1307 | if (size <= i->iov[k].iov_len) | |
1308 | break; | |
1309 | size -= i->iov[k].iov_len; | |
1310 | } | |
1311 | } | |
33844e66 | 1312 | return res; |
357f435d AV |
1313 | } |
1314 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1315 | ||
e76b6312 | 1316 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
241699cd AV |
1317 | size_t maxsize, |
1318 | struct page **pages, | |
8cefc107 | 1319 | int iter_head, |
241699cd AV |
1320 | size_t *start) |
1321 | { | |
1322 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1323 | unsigned int p_mask = pipe->ring_size - 1; |
1324 | ssize_t n = push_pipe(i, maxsize, &iter_head, start); | |
241699cd AV |
1325 | if (!n) |
1326 | return -EFAULT; | |
1327 | ||
1328 | maxsize = n; | |
1329 | n += *start; | |
1689c73a | 1330 | while (n > 0) { |
8cefc107 DH |
1331 | get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); |
1332 | iter_head++; | |
241699cd AV |
1333 | n -= PAGE_SIZE; |
1334 | } | |
1335 | ||
1336 | return maxsize; | |
1337 | } | |
1338 | ||
1339 | static ssize_t pipe_get_pages(struct iov_iter *i, | |
1340 | struct page **pages, size_t maxsize, unsigned maxpages, | |
1341 | size_t *start) | |
1342 | { | |
8cefc107 | 1343 | unsigned int iter_head, npages; |
241699cd | 1344 | size_t capacity; |
241699cd AV |
1345 | |
1346 | if (!sanity(i)) | |
1347 | return -EFAULT; | |
1348 | ||
8cefc107 DH |
1349 | data_start(i, &iter_head, start); |
1350 | /* Amount of free space: some of this one + all after this one */ | |
1351 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
1352 | capacity = min(npages, maxpages) * PAGE_SIZE - *start; | |
241699cd | 1353 | |
8cefc107 | 1354 | return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); |
241699cd AV |
1355 | } |
1356 | ||
7ff50620 DH |
1357 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
1358 | pgoff_t index, unsigned int nr_pages) | |
1359 | { | |
1360 | XA_STATE(xas, xa, index); | |
1361 | struct page *page; | |
1362 | unsigned int ret = 0; | |
1363 | ||
1364 | rcu_read_lock(); | |
1365 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1366 | if (xas_retry(&xas, page)) | |
1367 | continue; | |
1368 | ||
1369 | /* Has the page moved or been split? */ | |
1370 | if (unlikely(page != xas_reload(&xas))) { | |
1371 | xas_reset(&xas); | |
1372 | continue; | |
1373 | } | |
1374 | ||
1375 | pages[ret] = find_subpage(page, xas.xa_index); | |
1376 | get_page(pages[ret]); | |
1377 | if (++ret == nr_pages) | |
1378 | break; | |
1379 | } | |
1380 | rcu_read_unlock(); | |
1381 | return ret; | |
1382 | } | |
1383 | ||
1384 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, | |
1385 | struct page **pages, size_t maxsize, | |
1386 | unsigned maxpages, size_t *_start_offset) | |
1387 | { | |
1388 | unsigned nr, offset; | |
1389 | pgoff_t index, count; | |
1390 | size_t size = maxsize, actual; | |
1391 | loff_t pos; | |
1392 | ||
1393 | if (!size || !maxpages) | |
1394 | return 0; | |
1395 | ||
1396 | pos = i->xarray_start + i->iov_offset; | |
1397 | index = pos >> PAGE_SHIFT; | |
1398 | offset = pos & ~PAGE_MASK; | |
1399 | *_start_offset = offset; | |
1400 | ||
1401 | count = 1; | |
1402 | if (size > PAGE_SIZE - offset) { | |
1403 | size -= PAGE_SIZE - offset; | |
1404 | count += size >> PAGE_SHIFT; | |
1405 | size &= ~PAGE_MASK; | |
1406 | if (size) | |
1407 | count++; | |
1408 | } | |
1409 | ||
1410 | if (count > maxpages) | |
1411 | count = maxpages; | |
1412 | ||
1413 | nr = iter_xarray_populate_pages(pages, i->xarray, index, count); | |
1414 | if (nr == 0) | |
1415 | return 0; | |
1416 | ||
1417 | actual = PAGE_SIZE * nr; | |
1418 | actual -= offset; | |
1419 | if (nr == count && size > 0) { | |
1420 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1421 | actual -= PAGE_SIZE - (last_offset + size); | |
1422 | } | |
1423 | return actual; | |
1424 | } | |
1425 | ||
3d671ca6 AV |
1426 | /* must be done on non-empty ITER_IOVEC one */ |
1427 | static unsigned long first_iovec_segment(const struct iov_iter *i, | |
1428 | size_t *size, size_t *start, | |
1429 | size_t maxsize, unsigned maxpages) | |
1430 | { | |
1431 | size_t skip; | |
1432 | long k; | |
1433 | ||
1434 | for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { | |
1435 | unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; | |
1436 | size_t len = i->iov[k].iov_len - skip; | |
1437 | ||
1438 | if (unlikely(!len)) | |
1439 | continue; | |
1440 | if (len > maxsize) | |
1441 | len = maxsize; | |
1442 | len += (*start = addr % PAGE_SIZE); | |
1443 | if (len > maxpages * PAGE_SIZE) | |
1444 | len = maxpages * PAGE_SIZE; | |
1445 | *size = len; | |
1446 | return addr & PAGE_MASK; | |
1447 | } | |
1448 | BUG(); // if it had been empty, we wouldn't get called | |
1449 | } | |
1450 | ||
1451 | /* must be done on non-empty ITER_BVEC one */ | |
1452 | static struct page *first_bvec_segment(const struct iov_iter *i, | |
1453 | size_t *size, size_t *start, | |
1454 | size_t maxsize, unsigned maxpages) | |
1455 | { | |
1456 | struct page *page; | |
1457 | size_t skip = i->iov_offset, len; | |
1458 | ||
1459 | len = i->bvec->bv_len - skip; | |
1460 | if (len > maxsize) | |
1461 | len = maxsize; | |
1462 | skip += i->bvec->bv_offset; | |
1463 | page = i->bvec->bv_page + skip / PAGE_SIZE; | |
1464 | len += (*start = skip % PAGE_SIZE); | |
1465 | if (len > maxpages * PAGE_SIZE) | |
1466 | len = maxpages * PAGE_SIZE; | |
1467 | *size = len; | |
1468 | return page; | |
1469 | } | |
1470 | ||
62a8067a | 1471 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
2c80929c | 1472 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
1473 | size_t *start) |
1474 | { | |
3d671ca6 AV |
1475 | size_t len; |
1476 | int n, res; | |
1477 | ||
e5393fae AV |
1478 | if (maxsize > i->count) |
1479 | maxsize = i->count; | |
3d671ca6 AV |
1480 | if (!maxsize) |
1481 | return 0; | |
e5393fae | 1482 | |
3d671ca6 AV |
1483 | if (likely(iter_is_iovec(i))) { |
1484 | unsigned long addr; | |
e5393fae | 1485 | |
3d671ca6 | 1486 | addr = first_iovec_segment(i, &len, start, maxsize, maxpages); |
e5393fae | 1487 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
73b0140b IW |
1488 | res = get_user_pages_fast(addr, n, |
1489 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, | |
1490 | pages); | |
e5393fae AV |
1491 | if (unlikely(res < 0)) |
1492 | return res; | |
1493 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
3d671ca6 AV |
1494 | } |
1495 | if (iov_iter_is_bvec(i)) { | |
1496 | struct page *page; | |
1497 | ||
1498 | page = first_bvec_segment(i, &len, start, maxsize, maxpages); | |
1499 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1500 | while (n--) | |
1501 | get_page(*pages++ = page++); | |
1502 | return len - *start; | |
1503 | } | |
1504 | if (iov_iter_is_pipe(i)) | |
1505 | return pipe_get_pages(i, pages, maxsize, maxpages, start); | |
1506 | if (iov_iter_is_xarray(i)) | |
1507 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); | |
1508 | return -EFAULT; | |
62a8067a AV |
1509 | } |
1510 | EXPORT_SYMBOL(iov_iter_get_pages); | |
1511 | ||
1b17f1f2 AV |
1512 | static struct page **get_pages_array(size_t n) |
1513 | { | |
752ade68 | 1514 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); |
1b17f1f2 AV |
1515 | } |
1516 | ||
241699cd AV |
1517 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
1518 | struct page ***pages, size_t maxsize, | |
1519 | size_t *start) | |
1520 | { | |
1521 | struct page **p; | |
8cefc107 | 1522 | unsigned int iter_head, npages; |
d7760d63 | 1523 | ssize_t n; |
241699cd AV |
1524 | |
1525 | if (!sanity(i)) | |
1526 | return -EFAULT; | |
1527 | ||
8cefc107 DH |
1528 | data_start(i, &iter_head, start); |
1529 | /* Amount of free space: some of this one + all after this one */ | |
1530 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
241699cd AV |
1531 | n = npages * PAGE_SIZE - *start; |
1532 | if (maxsize > n) | |
1533 | maxsize = n; | |
1534 | else | |
1535 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); | |
1536 | p = get_pages_array(npages); | |
1537 | if (!p) | |
1538 | return -ENOMEM; | |
8cefc107 | 1539 | n = __pipe_get_pages(i, maxsize, p, iter_head, start); |
241699cd AV |
1540 | if (n > 0) |
1541 | *pages = p; | |
1542 | else | |
1543 | kvfree(p); | |
1544 | return n; | |
1545 | } | |
1546 | ||
7ff50620 DH |
1547 | static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, |
1548 | struct page ***pages, size_t maxsize, | |
1549 | size_t *_start_offset) | |
1550 | { | |
1551 | struct page **p; | |
1552 | unsigned nr, offset; | |
1553 | pgoff_t index, count; | |
1554 | size_t size = maxsize, actual; | |
1555 | loff_t pos; | |
1556 | ||
1557 | if (!size) | |
1558 | return 0; | |
1559 | ||
1560 | pos = i->xarray_start + i->iov_offset; | |
1561 | index = pos >> PAGE_SHIFT; | |
1562 | offset = pos & ~PAGE_MASK; | |
1563 | *_start_offset = offset; | |
1564 | ||
1565 | count = 1; | |
1566 | if (size > PAGE_SIZE - offset) { | |
1567 | size -= PAGE_SIZE - offset; | |
1568 | count += size >> PAGE_SHIFT; | |
1569 | size &= ~PAGE_MASK; | |
1570 | if (size) | |
1571 | count++; | |
1572 | } | |
1573 | ||
1574 | p = get_pages_array(count); | |
1575 | if (!p) | |
1576 | return -ENOMEM; | |
1577 | *pages = p; | |
1578 | ||
1579 | nr = iter_xarray_populate_pages(p, i->xarray, index, count); | |
1580 | if (nr == 0) | |
1581 | return 0; | |
1582 | ||
1583 | actual = PAGE_SIZE * nr; | |
1584 | actual -= offset; | |
1585 | if (nr == count && size > 0) { | |
1586 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1587 | actual -= PAGE_SIZE - (last_offset + size); | |
1588 | } | |
1589 | return actual; | |
1590 | } | |
1591 | ||
62a8067a AV |
1592 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
1593 | struct page ***pages, size_t maxsize, | |
1594 | size_t *start) | |
1595 | { | |
1b17f1f2 | 1596 | struct page **p; |
3d671ca6 AV |
1597 | size_t len; |
1598 | int n, res; | |
1b17f1f2 AV |
1599 | |
1600 | if (maxsize > i->count) | |
1601 | maxsize = i->count; | |
3d671ca6 AV |
1602 | if (!maxsize) |
1603 | return 0; | |
1b17f1f2 | 1604 | |
3d671ca6 AV |
1605 | if (likely(iter_is_iovec(i))) { |
1606 | unsigned long addr; | |
1b17f1f2 | 1607 | |
3d671ca6 | 1608 | addr = first_iovec_segment(i, &len, start, maxsize, ~0U); |
1b17f1f2 AV |
1609 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
1610 | p = get_pages_array(n); | |
1611 | if (!p) | |
1612 | return -ENOMEM; | |
73b0140b IW |
1613 | res = get_user_pages_fast(addr, n, |
1614 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); | |
1b17f1f2 AV |
1615 | if (unlikely(res < 0)) { |
1616 | kvfree(p); | |
1617 | return res; | |
1618 | } | |
1619 | *pages = p; | |
1620 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
3d671ca6 AV |
1621 | } |
1622 | if (iov_iter_is_bvec(i)) { | |
1623 | struct page *page; | |
1624 | ||
1625 | page = first_bvec_segment(i, &len, start, maxsize, ~0U); | |
1626 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1627 | *pages = p = get_pages_array(n); | |
1b17f1f2 AV |
1628 | if (!p) |
1629 | return -ENOMEM; | |
3d671ca6 AV |
1630 | while (n--) |
1631 | get_page(*p++ = page++); | |
1632 | return len - *start; | |
1633 | } | |
1634 | if (iov_iter_is_pipe(i)) | |
1635 | return pipe_get_pages_alloc(i, pages, maxsize, start); | |
1636 | if (iov_iter_is_xarray(i)) | |
1637 | return iter_xarray_get_pages_alloc(i, pages, maxsize, start); | |
1638 | return -EFAULT; | |
62a8067a AV |
1639 | } |
1640 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
1641 | ||
a604ec7e AV |
1642 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1643 | struct iov_iter *i) | |
1644 | { | |
a604ec7e | 1645 | __wsum sum, next; |
a604ec7e | 1646 | sum = *csum; |
9ea9ce04 | 1647 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1648 | WARN_ON(1); |
1649 | return 0; | |
1650 | } | |
7baa5099 AV |
1651 | iterate_and_advance(i, bytes, base, len, off, ({ |
1652 | next = csum_and_copy_from_user(base, addr + off, len); | |
2495bdcc | 1653 | sum = csum_block_add(sum, next, off); |
7baa5099 | 1654 | next ? 0 : len; |
a604ec7e | 1655 | }), ({ |
7baa5099 | 1656 | sum = csum_and_memcpy(addr + off, base, len, sum, off); |
a604ec7e AV |
1657 | }) |
1658 | ) | |
1659 | *csum = sum; | |
1660 | return bytes; | |
1661 | } | |
1662 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1663 | ||
52cbd23a | 1664 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
a604ec7e AV |
1665 | struct iov_iter *i) |
1666 | { | |
52cbd23a | 1667 | struct csum_state *csstate = _csstate; |
a604ec7e | 1668 | __wsum sum, next; |
78e1f386 | 1669 | |
78e1f386 | 1670 | if (unlikely(iov_iter_is_discard(i))) { |
241699cd AV |
1671 | WARN_ON(1); /* for now */ |
1672 | return 0; | |
1673 | } | |
6852df12 AV |
1674 | |
1675 | sum = csum_shift(csstate->csum, csstate->off); | |
1676 | if (unlikely(iov_iter_is_pipe(i))) | |
1677 | bytes = csum_and_copy_to_pipe_iter(addr, bytes, i, &sum); | |
1678 | else iterate_and_advance(i, bytes, base, len, off, ({ | |
7baa5099 | 1679 | next = csum_and_copy_to_user(addr + off, base, len); |
2495bdcc | 1680 | sum = csum_block_add(sum, next, off); |
7baa5099 | 1681 | next ? 0 : len; |
a604ec7e | 1682 | }), ({ |
7baa5099 | 1683 | sum = csum_and_memcpy(base, addr + off, len, sum, off); |
a604ec7e AV |
1684 | }) |
1685 | ) | |
594e450b AV |
1686 | csstate->csum = csum_shift(sum, csstate->off); |
1687 | csstate->off += bytes; | |
a604ec7e AV |
1688 | return bytes; |
1689 | } | |
1690 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1691 | ||
d05f4435 SG |
1692 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
1693 | struct iov_iter *i) | |
1694 | { | |
7999096f | 1695 | #ifdef CONFIG_CRYPTO_HASH |
d05f4435 SG |
1696 | struct ahash_request *hash = hashp; |
1697 | struct scatterlist sg; | |
1698 | size_t copied; | |
1699 | ||
1700 | copied = copy_to_iter(addr, bytes, i); | |
1701 | sg_init_one(&sg, addr, copied); | |
1702 | ahash_request_set_crypt(hash, &sg, NULL, copied); | |
1703 | crypto_ahash_update(hash); | |
1704 | return copied; | |
27fad74a Y |
1705 | #else |
1706 | return 0; | |
1707 | #endif | |
d05f4435 SG |
1708 | } |
1709 | EXPORT_SYMBOL(hash_and_copy_to_iter); | |
1710 | ||
66531c65 | 1711 | static int iov_npages(const struct iov_iter *i, int maxpages) |
62a8067a | 1712 | { |
66531c65 AV |
1713 | size_t skip = i->iov_offset, size = i->count; |
1714 | const struct iovec *p; | |
e0f2dc40 AV |
1715 | int npages = 0; |
1716 | ||
66531c65 AV |
1717 | for (p = i->iov; size; skip = 0, p++) { |
1718 | unsigned offs = offset_in_page(p->iov_base + skip); | |
1719 | size_t len = min(p->iov_len - skip, size); | |
e0f2dc40 | 1720 | |
66531c65 AV |
1721 | if (len) { |
1722 | size -= len; | |
1723 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1724 | if (unlikely(npages > maxpages)) | |
1725 | return maxpages; | |
1726 | } | |
1727 | } | |
1728 | return npages; | |
1729 | } | |
1730 | ||
1731 | static int bvec_npages(const struct iov_iter *i, int maxpages) | |
1732 | { | |
1733 | size_t skip = i->iov_offset, size = i->count; | |
1734 | const struct bio_vec *p; | |
1735 | int npages = 0; | |
1736 | ||
1737 | for (p = i->bvec; size; skip = 0, p++) { | |
1738 | unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; | |
1739 | size_t len = min(p->bv_len - skip, size); | |
1740 | ||
1741 | size -= len; | |
1742 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1743 | if (unlikely(npages > maxpages)) | |
1744 | return maxpages; | |
1745 | } | |
1746 | return npages; | |
1747 | } | |
1748 | ||
1749 | int iov_iter_npages(const struct iov_iter *i, int maxpages) | |
1750 | { | |
1751 | if (unlikely(!i->count)) | |
1752 | return 0; | |
1753 | /* iovec and kvec have identical layouts */ | |
1754 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1755 | return iov_npages(i, maxpages); | |
1756 | if (iov_iter_is_bvec(i)) | |
1757 | return bvec_npages(i, maxpages); | |
1758 | if (iov_iter_is_pipe(i)) { | |
8cefc107 | 1759 | unsigned int iter_head; |
66531c65 | 1760 | int npages; |
241699cd | 1761 | size_t off; |
241699cd AV |
1762 | |
1763 | if (!sanity(i)) | |
1764 | return 0; | |
1765 | ||
8cefc107 | 1766 | data_start(i, &iter_head, &off); |
241699cd | 1767 | /* some of this one + all after this one */ |
66531c65 AV |
1768 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); |
1769 | return min(npages, maxpages); | |
1770 | } | |
1771 | if (iov_iter_is_xarray(i)) { | |
e4f8df86 AV |
1772 | unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; |
1773 | int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); | |
66531c65 AV |
1774 | return min(npages, maxpages); |
1775 | } | |
1776 | return 0; | |
62a8067a | 1777 | } |
f67da30c | 1778 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1779 | |
1780 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1781 | { | |
1782 | *new = *old; | |
00e23707 | 1783 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1784 | WARN_ON(1); |
1785 | return NULL; | |
1786 | } | |
7ff50620 | 1787 | if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) |
9ea9ce04 | 1788 | return NULL; |
00e23707 | 1789 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1790 | return new->bvec = kmemdup(new->bvec, |
1791 | new->nr_segs * sizeof(struct bio_vec), | |
1792 | flags); | |
1793 | else | |
1794 | /* iovec and kvec have identical layout */ | |
1795 | return new->iov = kmemdup(new->iov, | |
1796 | new->nr_segs * sizeof(struct iovec), | |
1797 | flags); | |
1798 | } | |
1799 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1800 | |
bfdc5970 CH |
1801 | static int copy_compat_iovec_from_user(struct iovec *iov, |
1802 | const struct iovec __user *uvec, unsigned long nr_segs) | |
1803 | { | |
1804 | const struct compat_iovec __user *uiov = | |
1805 | (const struct compat_iovec __user *)uvec; | |
1806 | int ret = -EFAULT, i; | |
1807 | ||
a959a978 | 1808 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
1809 | return -EFAULT; |
1810 | ||
1811 | for (i = 0; i < nr_segs; i++) { | |
1812 | compat_uptr_t buf; | |
1813 | compat_ssize_t len; | |
1814 | ||
1815 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); | |
1816 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); | |
1817 | ||
1818 | /* check for compat_size_t not fitting in compat_ssize_t .. */ | |
1819 | if (len < 0) { | |
1820 | ret = -EINVAL; | |
1821 | goto uaccess_end; | |
1822 | } | |
1823 | iov[i].iov_base = compat_ptr(buf); | |
1824 | iov[i].iov_len = len; | |
1825 | } | |
1826 | ||
1827 | ret = 0; | |
1828 | uaccess_end: | |
1829 | user_access_end(); | |
1830 | return ret; | |
1831 | } | |
1832 | ||
1833 | static int copy_iovec_from_user(struct iovec *iov, | |
1834 | const struct iovec __user *uvec, unsigned long nr_segs) | |
fb041b59 DL |
1835 | { |
1836 | unsigned long seg; | |
fb041b59 | 1837 | |
bfdc5970 CH |
1838 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
1839 | return -EFAULT; | |
1840 | for (seg = 0; seg < nr_segs; seg++) { | |
1841 | if ((ssize_t)iov[seg].iov_len < 0) | |
1842 | return -EINVAL; | |
fb041b59 DL |
1843 | } |
1844 | ||
bfdc5970 CH |
1845 | return 0; |
1846 | } | |
1847 | ||
1848 | struct iovec *iovec_from_user(const struct iovec __user *uvec, | |
1849 | unsigned long nr_segs, unsigned long fast_segs, | |
1850 | struct iovec *fast_iov, bool compat) | |
1851 | { | |
1852 | struct iovec *iov = fast_iov; | |
1853 | int ret; | |
1854 | ||
fb041b59 | 1855 | /* |
bfdc5970 CH |
1856 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
1857 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
1858 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 1859 | */ |
bfdc5970 CH |
1860 | if (nr_segs == 0) |
1861 | return iov; | |
1862 | if (nr_segs > UIO_MAXIOV) | |
1863 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
1864 | if (nr_segs > fast_segs) { |
1865 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
1866 | if (!iov) |
1867 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 1868 | } |
bfdc5970 CH |
1869 | |
1870 | if (compat) | |
1871 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); | |
1872 | else | |
1873 | ret = copy_iovec_from_user(iov, uvec, nr_segs); | |
1874 | if (ret) { | |
1875 | if (iov != fast_iov) | |
1876 | kfree(iov); | |
1877 | return ERR_PTR(ret); | |
1878 | } | |
1879 | ||
1880 | return iov; | |
1881 | } | |
1882 | ||
1883 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
1884 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
1885 | struct iov_iter *i, bool compat) | |
1886 | { | |
1887 | ssize_t total_len = 0; | |
1888 | unsigned long seg; | |
1889 | struct iovec *iov; | |
1890 | ||
1891 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); | |
1892 | if (IS_ERR(iov)) { | |
1893 | *iovp = NULL; | |
1894 | return PTR_ERR(iov); | |
fb041b59 DL |
1895 | } |
1896 | ||
1897 | /* | |
bfdc5970 CH |
1898 | * According to the Single Unix Specification we should return EINVAL if |
1899 | * an element length is < 0 when cast to ssize_t or if the total length | |
1900 | * would overflow the ssize_t return value of the system call. | |
fb041b59 DL |
1901 | * |
1902 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
1903 | * overflow case. | |
1904 | */ | |
fb041b59 | 1905 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
1906 | ssize_t len = (ssize_t)iov[seg].iov_len; |
1907 | ||
bfdc5970 CH |
1908 | if (!access_ok(iov[seg].iov_base, len)) { |
1909 | if (iov != *iovp) | |
1910 | kfree(iov); | |
1911 | *iovp = NULL; | |
1912 | return -EFAULT; | |
fb041b59 | 1913 | } |
bfdc5970 CH |
1914 | |
1915 | if (len > MAX_RW_COUNT - total_len) { | |
1916 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
1917 | iov[seg].iov_len = len; |
1918 | } | |
bfdc5970 | 1919 | total_len += len; |
fb041b59 | 1920 | } |
bfdc5970 CH |
1921 | |
1922 | iov_iter_init(i, type, iov, nr_segs, total_len); | |
1923 | if (iov == *iovp) | |
1924 | *iovp = NULL; | |
1925 | else | |
1926 | *iovp = iov; | |
1927 | return total_len; | |
fb041b59 DL |
1928 | } |
1929 | ||
ffecee4f VN |
1930 | /** |
1931 | * import_iovec() - Copy an array of &struct iovec from userspace | |
1932 | * into the kernel, check that it is valid, and initialize a new | |
1933 | * &struct iov_iter iterator to access it. | |
1934 | * | |
1935 | * @type: One of %READ or %WRITE. | |
bfdc5970 | 1936 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
1937 | * @nr_segs: Number of elements in userspace array. |
1938 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 1939 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
1940 | * on-stack) kernel array. |
1941 | * @i: Pointer to iterator that will be initialized on success. | |
1942 | * | |
1943 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
1944 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
1945 | * array will be allocated and the result placed in *@iov. This means that | |
1946 | * the caller may call kfree() on *@iov regardless of whether the small | |
1947 | * on-stack array was used or not (and regardless of whether this function | |
1948 | * returns an error or not). | |
1949 | * | |
87e5e6da | 1950 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 1951 | */ |
bfdc5970 | 1952 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 1953 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 1954 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 1955 | { |
89cd35c5 CH |
1956 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
1957 | in_compat_syscall()); | |
bc917be8 AV |
1958 | } |
1959 | EXPORT_SYMBOL(import_iovec); | |
1960 | ||
bc917be8 AV |
1961 | int import_single_range(int rw, void __user *buf, size_t len, |
1962 | struct iovec *iov, struct iov_iter *i) | |
1963 | { | |
1964 | if (len > MAX_RW_COUNT) | |
1965 | len = MAX_RW_COUNT; | |
96d4f267 | 1966 | if (unlikely(!access_ok(buf, len))) |
bc917be8 AV |
1967 | return -EFAULT; |
1968 | ||
1969 | iov->iov_base = buf; | |
1970 | iov->iov_len = len; | |
1971 | iov_iter_init(i, rw, iov, 1, len); | |
1972 | return 0; | |
1973 | } | |
e1267585 | 1974 | EXPORT_SYMBOL(import_single_range); |
8fb0f47a JA |
1975 | |
1976 | /** | |
1977 | * iov_iter_restore() - Restore a &struct iov_iter to the same state as when | |
1978 | * iov_iter_save_state() was called. | |
1979 | * | |
1980 | * @i: &struct iov_iter to restore | |
1981 | * @state: state to restore from | |
1982 | * | |
1983 | * Used after iov_iter_save_state() to bring restore @i, if operations may | |
1984 | * have advanced it. | |
1985 | * | |
1986 | * Note: only works on ITER_IOVEC, ITER_BVEC, and ITER_KVEC | |
1987 | */ | |
1988 | void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) | |
1989 | { | |
1990 | if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i)) && | |
1991 | !iov_iter_is_kvec(i)) | |
1992 | return; | |
1993 | i->iov_offset = state->iov_offset; | |
1994 | i->count = state->count; | |
1995 | /* | |
1996 | * For the *vec iters, nr_segs + iov is constant - if we increment | |
1997 | * the vec, then we also decrement the nr_segs count. Hence we don't | |
1998 | * need to track both of these, just one is enough and we can deduct | |
1999 | * the other from that. ITER_KVEC and ITER_IOVEC are the same struct | |
2000 | * size, so we can just increment the iov pointer as they are unionzed. | |
2001 | * ITER_BVEC _may_ be the same size on some archs, but on others it is | |
2002 | * not. Be safe and handle it separately. | |
2003 | */ | |
2004 | BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); | |
2005 | if (iov_iter_is_bvec(i)) | |
2006 | i->bvec -= state->nr_segs - i->nr_segs; | |
2007 | else | |
2008 | i->iov -= state->nr_segs - i->nr_segs; | |
2009 | i->nr_segs = state->nr_segs; | |
2010 | } |