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; \ | |
44 | __v.bv_offset = offset % PAGE_SIZE; \ | |
45 | __v.bv_page = p->bv_page + offset / PAGE_SIZE; \ | |
46 | __v.bv_len = min(min(n, p->bv_len - skip), \ | |
47 | (size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ | |
48 | (void)(STEP); \ | |
49 | skip += __v.bv_len; \ | |
50 | if (skip == p->bv_len) { \ | |
51 | skip = 0; \ | |
52 | p++; \ | |
53 | } \ | |
54 | n -= __v.bv_len; \ | |
55 | } \ | |
56 | n = wanted - n; \ | |
04a31165 AV |
57 | } |
58 | ||
7ff50620 DH |
59 | #define iterate_xarray(i, n, __v, skip, STEP) { \ |
60 | struct page *head = NULL; \ | |
61 | size_t wanted = n, seg, offset; \ | |
62 | loff_t start = i->xarray_start + skip; \ | |
63 | pgoff_t index = start >> PAGE_SHIFT; \ | |
64 | int j; \ | |
65 | \ | |
66 | XA_STATE(xas, i->xarray, index); \ | |
67 | \ | |
68 | rcu_read_lock(); \ | |
69 | xas_for_each(&xas, head, ULONG_MAX) { \ | |
70 | if (xas_retry(&xas, head)) \ | |
71 | continue; \ | |
72 | if (WARN_ON(xa_is_value(head))) \ | |
73 | break; \ | |
74 | if (WARN_ON(PageHuge(head))) \ | |
75 | break; \ | |
76 | for (j = (head->index < index) ? index - head->index : 0; \ | |
77 | j < thp_nr_pages(head); j++) { \ | |
78 | __v.bv_page = head + j; \ | |
79 | offset = (i->xarray_start + skip) & ~PAGE_MASK; \ | |
80 | seg = PAGE_SIZE - offset; \ | |
81 | __v.bv_offset = offset; \ | |
82 | __v.bv_len = min(n, seg); \ | |
83 | (void)(STEP); \ | |
84 | n -= __v.bv_len; \ | |
85 | skip += __v.bv_len; \ | |
86 | if (n == 0) \ | |
87 | break; \ | |
88 | } \ | |
89 | if (n == 0) \ | |
90 | break; \ | |
91 | } \ | |
92 | rcu_read_unlock(); \ | |
93 | n = wanted - n; \ | |
94 | } | |
95 | ||
7ff50620 | 96 | #define iterate_and_advance(i, n, v, I, B, K, X) { \ |
dd254f5a AV |
97 | if (unlikely(i->count < n)) \ |
98 | n = i->count; \ | |
f5da8354 | 99 | if (likely(n)) { \ |
dd254f5a | 100 | size_t skip = i->iov_offset; \ |
28f38db7 | 101 | if (likely(iter_is_iovec(i))) { \ |
5c67aa90 | 102 | const struct iovec *iov = i->iov; \ |
28f38db7 AV |
103 | struct iovec v; \ |
104 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
28f38db7 AV |
105 | i->nr_segs -= iov - i->iov; \ |
106 | i->iov = iov; \ | |
107 | } else if (iov_iter_is_bvec(i)) { \ | |
1bdc76ae | 108 | const struct bio_vec *bvec = i->bvec; \ |
dd254f5a | 109 | struct bio_vec v; \ |
7491a2bf AV |
110 | iterate_bvec(i, n, v, bvec, skip, (B)) \ |
111 | i->nr_segs -= bvec - i->bvec; \ | |
112 | i->bvec = bvec; \ | |
28f38db7 | 113 | } else if (iov_iter_is_kvec(i)) { \ |
5c67aa90 | 114 | const struct kvec *kvec = i->kvec; \ |
dd254f5a | 115 | struct kvec v; \ |
5c67aa90 AV |
116 | iterate_iovec(i, n, v, kvec, skip, \ |
117 | ((void)(K),0)) \ | |
dd254f5a AV |
118 | i->nr_segs -= kvec - i->kvec; \ |
119 | i->kvec = kvec; \ | |
28f38db7 | 120 | } else if (iov_iter_is_xarray(i)) { \ |
7ff50620 DH |
121 | struct bio_vec v; \ |
122 | iterate_xarray(i, n, v, skip, (X)) \ | |
7ce2a91e | 123 | } \ |
dd254f5a AV |
124 | i->count -= n; \ |
125 | i->iov_offset = skip; \ | |
7ce2a91e | 126 | } \ |
7ce2a91e AV |
127 | } |
128 | ||
09fc68dc AV |
129 | static int copyout(void __user *to, const void *from, size_t n) |
130 | { | |
4d0e9df5 AL |
131 | if (should_fail_usercopy()) |
132 | return n; | |
96d4f267 | 133 | if (access_ok(to, n)) { |
d0ef4c36 | 134 | instrument_copy_to_user(to, from, n); |
09fc68dc AV |
135 | n = raw_copy_to_user(to, from, n); |
136 | } | |
137 | return n; | |
138 | } | |
139 | ||
140 | static int copyin(void *to, const void __user *from, size_t n) | |
141 | { | |
4d0e9df5 AL |
142 | if (should_fail_usercopy()) |
143 | return n; | |
96d4f267 | 144 | if (access_ok(from, n)) { |
d0ef4c36 | 145 | instrument_copy_from_user(to, from, n); |
09fc68dc AV |
146 | n = raw_copy_from_user(to, from, n); |
147 | } | |
148 | return n; | |
149 | } | |
150 | ||
62a8067a | 151 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
152 | struct iov_iter *i) |
153 | { | |
154 | size_t skip, copy, left, wanted; | |
155 | const struct iovec *iov; | |
156 | char __user *buf; | |
157 | void *kaddr, *from; | |
158 | ||
159 | if (unlikely(bytes > i->count)) | |
160 | bytes = i->count; | |
161 | ||
162 | if (unlikely(!bytes)) | |
163 | return 0; | |
164 | ||
09fc68dc | 165 | might_fault(); |
4f18cd31 AV |
166 | wanted = bytes; |
167 | iov = i->iov; | |
168 | skip = i->iov_offset; | |
169 | buf = iov->iov_base + skip; | |
170 | copy = min(bytes, iov->iov_len - skip); | |
171 | ||
3fa6c507 | 172 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { |
4f18cd31 AV |
173 | kaddr = kmap_atomic(page); |
174 | from = kaddr + offset; | |
175 | ||
176 | /* first chunk, usually the only one */ | |
09fc68dc | 177 | left = copyout(buf, from, copy); |
4f18cd31 AV |
178 | copy -= left; |
179 | skip += copy; | |
180 | from += copy; | |
181 | bytes -= copy; | |
182 | ||
183 | while (unlikely(!left && bytes)) { | |
184 | iov++; | |
185 | buf = iov->iov_base; | |
186 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 187 | left = copyout(buf, from, copy); |
4f18cd31 AV |
188 | copy -= left; |
189 | skip = copy; | |
190 | from += copy; | |
191 | bytes -= copy; | |
192 | } | |
193 | if (likely(!bytes)) { | |
194 | kunmap_atomic(kaddr); | |
195 | goto done; | |
196 | } | |
197 | offset = from - kaddr; | |
198 | buf += copy; | |
199 | kunmap_atomic(kaddr); | |
200 | copy = min(bytes, iov->iov_len - skip); | |
201 | } | |
202 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 203 | |
4f18cd31 AV |
204 | kaddr = kmap(page); |
205 | from = kaddr + offset; | |
09fc68dc | 206 | left = copyout(buf, from, copy); |
4f18cd31 AV |
207 | copy -= left; |
208 | skip += copy; | |
209 | from += copy; | |
210 | bytes -= copy; | |
211 | while (unlikely(!left && bytes)) { | |
212 | iov++; | |
213 | buf = iov->iov_base; | |
214 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 215 | left = copyout(buf, from, copy); |
4f18cd31 AV |
216 | copy -= left; |
217 | skip = copy; | |
218 | from += copy; | |
219 | bytes -= copy; | |
220 | } | |
221 | kunmap(page); | |
3fa6c507 | 222 | |
4f18cd31 | 223 | done: |
81055e58 AV |
224 | if (skip == iov->iov_len) { |
225 | iov++; | |
226 | skip = 0; | |
227 | } | |
4f18cd31 AV |
228 | i->count -= wanted - bytes; |
229 | i->nr_segs -= iov - i->iov; | |
230 | i->iov = iov; | |
231 | i->iov_offset = skip; | |
232 | return wanted - bytes; | |
233 | } | |
4f18cd31 | 234 | |
62a8067a | 235 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
236 | struct iov_iter *i) |
237 | { | |
238 | size_t skip, copy, left, wanted; | |
239 | const struct iovec *iov; | |
240 | char __user *buf; | |
241 | void *kaddr, *to; | |
242 | ||
243 | if (unlikely(bytes > i->count)) | |
244 | bytes = i->count; | |
245 | ||
246 | if (unlikely(!bytes)) | |
247 | return 0; | |
248 | ||
09fc68dc | 249 | might_fault(); |
f0d1bec9 AV |
250 | wanted = bytes; |
251 | iov = i->iov; | |
252 | skip = i->iov_offset; | |
253 | buf = iov->iov_base + skip; | |
254 | copy = min(bytes, iov->iov_len - skip); | |
255 | ||
3fa6c507 | 256 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { |
f0d1bec9 AV |
257 | kaddr = kmap_atomic(page); |
258 | to = kaddr + offset; | |
259 | ||
260 | /* first chunk, usually the only one */ | |
09fc68dc | 261 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
262 | copy -= left; |
263 | skip += copy; | |
264 | to += copy; | |
265 | bytes -= copy; | |
266 | ||
267 | while (unlikely(!left && bytes)) { | |
268 | iov++; | |
269 | buf = iov->iov_base; | |
270 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 271 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
272 | copy -= left; |
273 | skip = copy; | |
274 | to += copy; | |
275 | bytes -= copy; | |
276 | } | |
277 | if (likely(!bytes)) { | |
278 | kunmap_atomic(kaddr); | |
279 | goto done; | |
280 | } | |
281 | offset = to - kaddr; | |
282 | buf += copy; | |
283 | kunmap_atomic(kaddr); | |
284 | copy = min(bytes, iov->iov_len - skip); | |
285 | } | |
286 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 287 | |
f0d1bec9 AV |
288 | kaddr = kmap(page); |
289 | to = kaddr + offset; | |
09fc68dc | 290 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
291 | copy -= left; |
292 | skip += copy; | |
293 | to += copy; | |
294 | bytes -= copy; | |
295 | while (unlikely(!left && bytes)) { | |
296 | iov++; | |
297 | buf = iov->iov_base; | |
298 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 299 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
300 | copy -= left; |
301 | skip = copy; | |
302 | to += copy; | |
303 | bytes -= copy; | |
304 | } | |
305 | kunmap(page); | |
3fa6c507 | 306 | |
f0d1bec9 | 307 | done: |
81055e58 AV |
308 | if (skip == iov->iov_len) { |
309 | iov++; | |
310 | skip = 0; | |
311 | } | |
f0d1bec9 AV |
312 | i->count -= wanted - bytes; |
313 | i->nr_segs -= iov - i->iov; | |
314 | i->iov = iov; | |
315 | i->iov_offset = skip; | |
316 | return wanted - bytes; | |
317 | } | |
f0d1bec9 | 318 | |
241699cd AV |
319 | #ifdef PIPE_PARANOIA |
320 | static bool sanity(const struct iov_iter *i) | |
321 | { | |
322 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
323 | unsigned int p_head = pipe->head; |
324 | unsigned int p_tail = pipe->tail; | |
325 | unsigned int p_mask = pipe->ring_size - 1; | |
326 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); | |
327 | unsigned int i_head = i->head; | |
328 | unsigned int idx; | |
329 | ||
241699cd AV |
330 | if (i->iov_offset) { |
331 | struct pipe_buffer *p; | |
8cefc107 | 332 | if (unlikely(p_occupancy == 0)) |
241699cd | 333 | goto Bad; // pipe must be non-empty |
8cefc107 | 334 | if (unlikely(i_head != p_head - 1)) |
241699cd AV |
335 | goto Bad; // must be at the last buffer... |
336 | ||
8cefc107 | 337 | p = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
338 | if (unlikely(p->offset + p->len != i->iov_offset)) |
339 | goto Bad; // ... at the end of segment | |
340 | } else { | |
8cefc107 | 341 | if (i_head != p_head) |
241699cd AV |
342 | goto Bad; // must be right after the last buffer |
343 | } | |
344 | return true; | |
345 | Bad: | |
8cefc107 DH |
346 | printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); |
347 | printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", | |
348 | p_head, p_tail, pipe->ring_size); | |
349 | for (idx = 0; idx < pipe->ring_size; idx++) | |
241699cd AV |
350 | printk(KERN_ERR "[%p %p %d %d]\n", |
351 | pipe->bufs[idx].ops, | |
352 | pipe->bufs[idx].page, | |
353 | pipe->bufs[idx].offset, | |
354 | pipe->bufs[idx].len); | |
355 | WARN_ON(1); | |
356 | return false; | |
357 | } | |
358 | #else | |
359 | #define sanity(i) true | |
360 | #endif | |
361 | ||
241699cd AV |
362 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
363 | struct iov_iter *i) | |
364 | { | |
365 | struct pipe_inode_info *pipe = i->pipe; | |
366 | struct pipe_buffer *buf; | |
8cefc107 DH |
367 | unsigned int p_tail = pipe->tail; |
368 | unsigned int p_mask = pipe->ring_size - 1; | |
369 | unsigned int i_head = i->head; | |
241699cd | 370 | size_t off; |
241699cd AV |
371 | |
372 | if (unlikely(bytes > i->count)) | |
373 | bytes = i->count; | |
374 | ||
375 | if (unlikely(!bytes)) | |
376 | return 0; | |
377 | ||
378 | if (!sanity(i)) | |
379 | return 0; | |
380 | ||
381 | off = i->iov_offset; | |
8cefc107 | 382 | buf = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
383 | if (off) { |
384 | if (offset == off && buf->page == page) { | |
385 | /* merge with the last one */ | |
386 | buf->len += bytes; | |
387 | i->iov_offset += bytes; | |
388 | goto out; | |
389 | } | |
8cefc107 DH |
390 | i_head++; |
391 | buf = &pipe->bufs[i_head & p_mask]; | |
241699cd | 392 | } |
6718b6f8 | 393 | if (pipe_full(i_head, p_tail, pipe->max_usage)) |
241699cd | 394 | return 0; |
8cefc107 | 395 | |
241699cd | 396 | buf->ops = &page_cache_pipe_buf_ops; |
8cefc107 DH |
397 | get_page(page); |
398 | buf->page = page; | |
241699cd AV |
399 | buf->offset = offset; |
400 | buf->len = bytes; | |
8cefc107 DH |
401 | |
402 | pipe->head = i_head + 1; | |
241699cd | 403 | i->iov_offset = offset + bytes; |
8cefc107 | 404 | i->head = i_head; |
241699cd AV |
405 | out: |
406 | i->count -= bytes; | |
407 | return bytes; | |
408 | } | |
409 | ||
171a0203 AA |
410 | /* |
411 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of | |
412 | * bytes. For each iovec, fault in each page that constitutes the iovec. | |
413 | * | |
414 | * Return 0 on success, or non-zero if the memory could not be accessed (i.e. | |
415 | * because it is an invalid address). | |
416 | */ | |
8409a0d2 | 417 | int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) |
171a0203 | 418 | { |
0e8f0d67 | 419 | if (iter_is_iovec(i)) { |
8409a0d2 AV |
420 | const struct iovec *p; |
421 | size_t skip; | |
422 | ||
423 | if (bytes > i->count) | |
424 | bytes = i->count; | |
425 | for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { | |
426 | size_t len = min(bytes, p->iov_len - skip); | |
427 | int err; | |
428 | ||
429 | if (unlikely(!len)) | |
430 | continue; | |
431 | err = fault_in_pages_readable(p->iov_base + skip, len); | |
171a0203 | 432 | if (unlikely(err)) |
8409a0d2 AV |
433 | return err; |
434 | bytes -= len; | |
435 | } | |
171a0203 AA |
436 | } |
437 | return 0; | |
438 | } | |
d4690f1e | 439 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
171a0203 | 440 | |
aa563d7b | 441 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
442 | const struct iovec *iov, unsigned long nr_segs, |
443 | size_t count) | |
444 | { | |
aa563d7b | 445 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
446 | WARN_ON_ONCE(uaccess_kernel()); |
447 | *i = (struct iov_iter) { | |
448 | .iter_type = ITER_IOVEC, | |
449 | .data_source = direction, | |
450 | .iov = iov, | |
451 | .nr_segs = nr_segs, | |
452 | .iov_offset = 0, | |
453 | .count = count | |
454 | }; | |
71d8e532 AV |
455 | } |
456 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 457 | |
241699cd AV |
458 | static inline bool allocated(struct pipe_buffer *buf) |
459 | { | |
460 | return buf->ops == &default_pipe_buf_ops; | |
461 | } | |
462 | ||
8cefc107 DH |
463 | static inline void data_start(const struct iov_iter *i, |
464 | unsigned int *iter_headp, size_t *offp) | |
241699cd | 465 | { |
8cefc107 DH |
466 | unsigned int p_mask = i->pipe->ring_size - 1; |
467 | unsigned int iter_head = i->head; | |
241699cd | 468 | size_t off = i->iov_offset; |
8cefc107 DH |
469 | |
470 | if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || | |
471 | off == PAGE_SIZE)) { | |
472 | iter_head++; | |
241699cd AV |
473 | off = 0; |
474 | } | |
8cefc107 | 475 | *iter_headp = iter_head; |
241699cd AV |
476 | *offp = off; |
477 | } | |
478 | ||
479 | static size_t push_pipe(struct iov_iter *i, size_t size, | |
8cefc107 | 480 | int *iter_headp, size_t *offp) |
241699cd AV |
481 | { |
482 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
483 | unsigned int p_tail = pipe->tail; |
484 | unsigned int p_mask = pipe->ring_size - 1; | |
485 | unsigned int iter_head; | |
241699cd | 486 | size_t off; |
241699cd AV |
487 | ssize_t left; |
488 | ||
489 | if (unlikely(size > i->count)) | |
490 | size = i->count; | |
491 | if (unlikely(!size)) | |
492 | return 0; | |
493 | ||
494 | left = size; | |
8cefc107 DH |
495 | data_start(i, &iter_head, &off); |
496 | *iter_headp = iter_head; | |
241699cd AV |
497 | *offp = off; |
498 | if (off) { | |
499 | left -= PAGE_SIZE - off; | |
500 | if (left <= 0) { | |
8cefc107 | 501 | pipe->bufs[iter_head & p_mask].len += size; |
241699cd AV |
502 | return size; |
503 | } | |
8cefc107 DH |
504 | pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; |
505 | iter_head++; | |
241699cd | 506 | } |
6718b6f8 | 507 | while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { |
8cefc107 | 508 | struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; |
241699cd AV |
509 | struct page *page = alloc_page(GFP_USER); |
510 | if (!page) | |
511 | break; | |
8cefc107 DH |
512 | |
513 | buf->ops = &default_pipe_buf_ops; | |
514 | buf->page = page; | |
515 | buf->offset = 0; | |
516 | buf->len = min_t(ssize_t, left, PAGE_SIZE); | |
517 | left -= buf->len; | |
518 | iter_head++; | |
519 | pipe->head = iter_head; | |
520 | ||
521 | if (left == 0) | |
241699cd | 522 | return size; |
241699cd AV |
523 | } |
524 | return size - left; | |
525 | } | |
526 | ||
527 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, | |
528 | struct iov_iter *i) | |
529 | { | |
530 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
531 | unsigned int p_mask = pipe->ring_size - 1; |
532 | unsigned int i_head; | |
241699cd | 533 | size_t n, off; |
241699cd AV |
534 | |
535 | if (!sanity(i)) | |
536 | return 0; | |
537 | ||
8cefc107 | 538 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
539 | if (unlikely(!n)) |
540 | return 0; | |
8cefc107 | 541 | do { |
241699cd | 542 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
543 | memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); |
544 | i->head = i_head; | |
241699cd AV |
545 | i->iov_offset = off + chunk; |
546 | n -= chunk; | |
547 | addr += chunk; | |
8cefc107 DH |
548 | off = 0; |
549 | i_head++; | |
550 | } while (n); | |
241699cd AV |
551 | i->count -= bytes; |
552 | return bytes; | |
553 | } | |
554 | ||
f9152895 AV |
555 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
556 | __wsum sum, size_t off) | |
557 | { | |
cc44c17b | 558 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
f9152895 AV |
559 | return csum_block_add(sum, next, off); |
560 | } | |
561 | ||
78e1f386 | 562 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
52cbd23a WB |
563 | struct csum_state *csstate, |
564 | struct iov_iter *i) | |
78e1f386 AV |
565 | { |
566 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 | 567 | unsigned int p_mask = pipe->ring_size - 1; |
52cbd23a WB |
568 | __wsum sum = csstate->csum; |
569 | size_t off = csstate->off; | |
8cefc107 | 570 | unsigned int i_head; |
78e1f386 | 571 | size_t n, r; |
78e1f386 AV |
572 | |
573 | if (!sanity(i)) | |
574 | return 0; | |
575 | ||
8cefc107 | 576 | bytes = n = push_pipe(i, bytes, &i_head, &r); |
78e1f386 AV |
577 | if (unlikely(!n)) |
578 | return 0; | |
8cefc107 | 579 | do { |
78e1f386 | 580 | size_t chunk = min_t(size_t, n, PAGE_SIZE - r); |
8cefc107 | 581 | char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); |
f9152895 | 582 | sum = csum_and_memcpy(p + r, addr, chunk, sum, off); |
78e1f386 | 583 | kunmap_atomic(p); |
8cefc107 | 584 | i->head = i_head; |
78e1f386 AV |
585 | i->iov_offset = r + chunk; |
586 | n -= chunk; | |
587 | off += chunk; | |
588 | addr += chunk; | |
8cefc107 DH |
589 | r = 0; |
590 | i_head++; | |
591 | } while (n); | |
78e1f386 | 592 | i->count -= bytes; |
52cbd23a WB |
593 | csstate->csum = sum; |
594 | csstate->off = off; | |
78e1f386 AV |
595 | return bytes; |
596 | } | |
597 | ||
aa28de27 | 598 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 599 | { |
36f7a8a4 | 600 | const char *from = addr; |
00e23707 | 601 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 602 | return copy_pipe_to_iter(addr, bytes, i); |
09fc68dc AV |
603 | if (iter_is_iovec(i)) |
604 | might_fault(); | |
3d4d3e48 | 605 | iterate_and_advance(i, bytes, v, |
09fc68dc | 606 | copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
3d4d3e48 | 607 | memcpy_to_page(v.bv_page, v.bv_offset, |
a280455f | 608 | (from += v.bv_len) - v.bv_len, v.bv_len), |
7ff50620 DH |
609 | memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
610 | memcpy_to_page(v.bv_page, v.bv_offset, | |
611 | (from += v.bv_len) - v.bv_len, v.bv_len) | |
3d4d3e48 | 612 | ) |
62a8067a | 613 | |
3d4d3e48 | 614 | return bytes; |
c35e0248 | 615 | } |
aa28de27 | 616 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 617 | |
ec6347bb DW |
618 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
619 | static int copyout_mc(void __user *to, const void *from, size_t n) | |
8780356e | 620 | { |
96d4f267 | 621 | if (access_ok(to, n)) { |
d0ef4c36 | 622 | instrument_copy_to_user(to, from, n); |
ec6347bb | 623 | n = copy_mc_to_user((__force void *) to, from, n); |
8780356e DW |
624 | } |
625 | return n; | |
626 | } | |
627 | ||
ec6347bb | 628 | static unsigned long copy_mc_to_page(struct page *page, size_t offset, |
8780356e DW |
629 | const char *from, size_t len) |
630 | { | |
631 | unsigned long ret; | |
632 | char *to; | |
633 | ||
634 | to = kmap_atomic(page); | |
ec6347bb | 635 | ret = copy_mc_to_kernel(to + offset, from, len); |
8780356e DW |
636 | kunmap_atomic(to); |
637 | ||
638 | return ret; | |
639 | } | |
640 | ||
ec6347bb | 641 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
ca146f6f DW |
642 | struct iov_iter *i) |
643 | { | |
644 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
645 | unsigned int p_mask = pipe->ring_size - 1; |
646 | unsigned int i_head; | |
ca146f6f | 647 | size_t n, off, xfer = 0; |
ca146f6f DW |
648 | |
649 | if (!sanity(i)) | |
650 | return 0; | |
651 | ||
8cefc107 | 652 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
ca146f6f DW |
653 | if (unlikely(!n)) |
654 | return 0; | |
8cefc107 | 655 | do { |
ca146f6f DW |
656 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
657 | unsigned long rem; | |
658 | ||
ec6347bb | 659 | rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, |
8cefc107 DH |
660 | off, addr, chunk); |
661 | i->head = i_head; | |
ca146f6f DW |
662 | i->iov_offset = off + chunk - rem; |
663 | xfer += chunk - rem; | |
664 | if (rem) | |
665 | break; | |
666 | n -= chunk; | |
667 | addr += chunk; | |
8cefc107 DH |
668 | off = 0; |
669 | i_head++; | |
670 | } while (n); | |
ca146f6f DW |
671 | i->count -= xfer; |
672 | return xfer; | |
673 | } | |
674 | ||
bf3eeb9b | 675 | /** |
ec6347bb | 676 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
bf3eeb9b DW |
677 | * @addr: source kernel address |
678 | * @bytes: total transfer length | |
679 | * @iter: destination iterator | |
680 | * | |
ec6347bb DW |
681 | * The pmem driver deploys this for the dax operation |
682 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the | |
683 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes | |
684 | * successfully copied. | |
bf3eeb9b | 685 | * |
ec6347bb | 686 | * The main differences between this and typical _copy_to_iter(). |
bf3eeb9b DW |
687 | * |
688 | * * Typical tail/residue handling after a fault retries the copy | |
689 | * byte-by-byte until the fault happens again. Re-triggering machine | |
690 | * checks is potentially fatal so the implementation uses source | |
691 | * alignment and poison alignment assumptions to avoid re-triggering | |
692 | * hardware exceptions. | |
693 | * | |
694 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. | |
695 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return | |
696 | * a short copy. | |
bf3eeb9b | 697 | */ |
ec6347bb | 698 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
8780356e DW |
699 | { |
700 | const char *from = addr; | |
701 | unsigned long rem, curr_addr, s_addr = (unsigned long) addr; | |
702 | ||
00e23707 | 703 | if (unlikely(iov_iter_is_pipe(i))) |
ec6347bb | 704 | return copy_mc_pipe_to_iter(addr, bytes, i); |
8780356e DW |
705 | if (iter_is_iovec(i)) |
706 | might_fault(); | |
707 | iterate_and_advance(i, bytes, v, | |
ec6347bb DW |
708 | copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, |
709 | v.iov_len), | |
8780356e | 710 | ({ |
ec6347bb DW |
711 | rem = copy_mc_to_page(v.bv_page, v.bv_offset, |
712 | (from += v.bv_len) - v.bv_len, v.bv_len); | |
8780356e DW |
713 | if (rem) { |
714 | curr_addr = (unsigned long) from; | |
715 | bytes = curr_addr - s_addr - rem; | |
716 | return bytes; | |
717 | } | |
718 | }), | |
719 | ({ | |
ec6347bb DW |
720 | rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) |
721 | - v.iov_len, v.iov_len); | |
8780356e DW |
722 | if (rem) { |
723 | curr_addr = (unsigned long) from; | |
724 | bytes = curr_addr - s_addr - rem; | |
725 | return bytes; | |
726 | } | |
7ff50620 DH |
727 | }), |
728 | ({ | |
729 | rem = copy_mc_to_page(v.bv_page, v.bv_offset, | |
730 | (from += v.bv_len) - v.bv_len, v.bv_len); | |
731 | if (rem) { | |
732 | curr_addr = (unsigned long) from; | |
733 | bytes = curr_addr - s_addr - rem; | |
734 | rcu_read_unlock(); | |
3d14ec1f DH |
735 | i->iov_offset += bytes; |
736 | i->count -= bytes; | |
7ff50620 DH |
737 | return bytes; |
738 | } | |
8780356e DW |
739 | }) |
740 | ) | |
741 | ||
742 | return bytes; | |
743 | } | |
ec6347bb DW |
744 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
745 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 746 | |
aa28de27 | 747 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 748 | { |
0dbca9a4 | 749 | char *to = addr; |
00e23707 | 750 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
751 | WARN_ON(1); |
752 | return 0; | |
753 | } | |
09fc68dc AV |
754 | if (iter_is_iovec(i)) |
755 | might_fault(); | |
0dbca9a4 | 756 | iterate_and_advance(i, bytes, v, |
09fc68dc | 757 | copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
0dbca9a4 | 758 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 759 | v.bv_offset, v.bv_len), |
7ff50620 DH |
760 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
761 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
762 | v.bv_offset, v.bv_len) | |
0dbca9a4 AV |
763 | ) |
764 | ||
765 | return bytes; | |
c35e0248 | 766 | } |
aa28de27 | 767 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 768 | |
aa28de27 | 769 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 AV |
770 | { |
771 | char *to = addr; | |
00e23707 | 772 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
773 | WARN_ON(1); |
774 | return 0; | |
775 | } | |
aa583096 | 776 | iterate_and_advance(i, bytes, v, |
3f763453 | 777 | __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
aa583096 AV |
778 | v.iov_base, v.iov_len), |
779 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
780 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
781 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
782 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
783 | v.bv_offset, v.bv_len) | |
aa583096 AV |
784 | ) |
785 | ||
786 | return bytes; | |
787 | } | |
aa28de27 | 788 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 789 | |
0aed55af | 790 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
791 | /** |
792 | * _copy_from_iter_flushcache - write destination through cpu cache | |
793 | * @addr: destination kernel address | |
794 | * @bytes: total transfer length | |
795 | * @iter: source iterator | |
796 | * | |
797 | * The pmem driver arranges for filesystem-dax to use this facility via | |
798 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
799 | * are flushed through the CPU cache. It is differentiated from | |
800 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
801 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
802 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
803 | * instructions that strand dirty-data in the cache. | |
804 | */ | |
6a37e940 | 805 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af DW |
806 | { |
807 | char *to = addr; | |
00e23707 | 808 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
809 | WARN_ON(1); |
810 | return 0; | |
811 | } | |
812 | iterate_and_advance(i, bytes, v, | |
813 | __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, | |
814 | v.iov_base, v.iov_len), | |
815 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
816 | v.bv_offset, v.bv_len), | |
817 | memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, | |
7ff50620 DH |
818 | v.iov_len), |
819 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
820 | v.bv_offset, v.bv_len) | |
0aed55af DW |
821 | ) |
822 | ||
823 | return bytes; | |
824 | } | |
6a37e940 | 825 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
826 | #endif |
827 | ||
72e809ed AV |
828 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
829 | { | |
6daef95b ED |
830 | struct page *head; |
831 | size_t v = n + offset; | |
832 | ||
833 | /* | |
834 | * The general case needs to access the page order in order | |
835 | * to compute the page size. | |
836 | * However, we mostly deal with order-0 pages and thus can | |
837 | * avoid a possible cache line miss for requests that fit all | |
838 | * page orders. | |
839 | */ | |
840 | if (n <= v && v <= PAGE_SIZE) | |
841 | return true; | |
842 | ||
843 | head = compound_head(page); | |
844 | v += (page - head) << PAGE_SHIFT; | |
a90bcb86 | 845 | |
a50b854e | 846 | if (likely(n <= v && v <= (page_size(head)))) |
72e809ed AV |
847 | return true; |
848 | WARN_ON(1); | |
849 | return false; | |
850 | } | |
cbbd26b8 | 851 | |
08aa6479 | 852 | static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
62a8067a AV |
853 | struct iov_iter *i) |
854 | { | |
28f38db7 AV |
855 | if (likely(iter_is_iovec(i))) |
856 | return copy_page_to_iter_iovec(page, offset, bytes, i); | |
857 | if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { | |
d271524a AV |
858 | void *kaddr = kmap_atomic(page); |
859 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); | |
860 | kunmap_atomic(kaddr); | |
861 | return wanted; | |
28f38db7 AV |
862 | } |
863 | if (iov_iter_is_pipe(i)) | |
864 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
865 | if (unlikely(iov_iter_is_discard(i))) { | |
a506abc7 AV |
866 | if (unlikely(i->count < bytes)) |
867 | bytes = i->count; | |
868 | i->count -= bytes; | |
9ea9ce04 | 869 | return bytes; |
28f38db7 AV |
870 | } |
871 | WARN_ON(1); | |
872 | return 0; | |
62a8067a | 873 | } |
08aa6479 AV |
874 | |
875 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, | |
876 | struct iov_iter *i) | |
877 | { | |
878 | size_t res = 0; | |
879 | if (unlikely(!page_copy_sane(page, offset, bytes))) | |
880 | return 0; | |
881 | page += offset / PAGE_SIZE; // first subpage | |
882 | offset %= PAGE_SIZE; | |
883 | while (1) { | |
884 | size_t n = __copy_page_to_iter(page, offset, | |
885 | min(bytes, (size_t)PAGE_SIZE - offset), i); | |
886 | res += n; | |
887 | bytes -= n; | |
888 | if (!bytes || !n) | |
889 | break; | |
890 | offset += n; | |
891 | if (offset == PAGE_SIZE) { | |
892 | page++; | |
893 | offset = 0; | |
894 | } | |
895 | } | |
896 | return res; | |
897 | } | |
62a8067a AV |
898 | EXPORT_SYMBOL(copy_page_to_iter); |
899 | ||
900 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
901 | struct iov_iter *i) | |
902 | { | |
72e809ed AV |
903 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
904 | return 0; | |
28f38db7 AV |
905 | if (likely(iter_is_iovec(i))) |
906 | return copy_page_from_iter_iovec(page, offset, bytes, i); | |
907 | if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { | |
d271524a | 908 | void *kaddr = kmap_atomic(page); |
aa28de27 | 909 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
d271524a AV |
910 | kunmap_atomic(kaddr); |
911 | return wanted; | |
28f38db7 AV |
912 | } |
913 | WARN_ON(1); | |
914 | return 0; | |
62a8067a AV |
915 | } |
916 | EXPORT_SYMBOL(copy_page_from_iter); | |
917 | ||
241699cd AV |
918 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
919 | { | |
920 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
921 | unsigned int p_mask = pipe->ring_size - 1; |
922 | unsigned int i_head; | |
241699cd | 923 | size_t n, off; |
241699cd AV |
924 | |
925 | if (!sanity(i)) | |
926 | return 0; | |
927 | ||
8cefc107 | 928 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
929 | if (unlikely(!n)) |
930 | return 0; | |
931 | ||
8cefc107 | 932 | do { |
241699cd | 933 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
934 | memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); |
935 | i->head = i_head; | |
241699cd AV |
936 | i->iov_offset = off + chunk; |
937 | n -= chunk; | |
8cefc107 DH |
938 | off = 0; |
939 | i_head++; | |
940 | } while (n); | |
241699cd AV |
941 | i->count -= bytes; |
942 | return bytes; | |
943 | } | |
944 | ||
c35e0248 MW |
945 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
946 | { | |
00e23707 | 947 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 948 | return pipe_zero(bytes, i); |
8442fa46 | 949 | iterate_and_advance(i, bytes, v, |
09fc68dc | 950 | clear_user(v.iov_base, v.iov_len), |
a280455f | 951 | memzero_page(v.bv_page, v.bv_offset, v.bv_len), |
7ff50620 DH |
952 | memset(v.iov_base, 0, v.iov_len), |
953 | memzero_page(v.bv_page, v.bv_offset, v.bv_len) | |
8442fa46 AV |
954 | ) |
955 | ||
956 | return bytes; | |
c35e0248 MW |
957 | } |
958 | EXPORT_SYMBOL(iov_iter_zero); | |
959 | ||
f0b65f39 AV |
960 | size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, |
961 | struct iov_iter *i) | |
62a8067a | 962 | { |
04a31165 | 963 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
964 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
965 | kunmap_atomic(kaddr); | |
966 | return 0; | |
967 | } | |
9ea9ce04 | 968 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
969 | kunmap_atomic(kaddr); |
970 | WARN_ON(1); | |
971 | return 0; | |
972 | } | |
f0b65f39 | 973 | iterate_and_advance(i, bytes, v, |
09fc68dc | 974 | copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
04a31165 | 975 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 976 | v.bv_offset, v.bv_len), |
7ff50620 DH |
977 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
978 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, | |
979 | v.bv_offset, v.bv_len) | |
04a31165 AV |
980 | ) |
981 | kunmap_atomic(kaddr); | |
982 | return bytes; | |
62a8067a | 983 | } |
f0b65f39 | 984 | EXPORT_SYMBOL(copy_page_from_iter_atomic); |
62a8067a | 985 | |
b9dc6f65 AV |
986 | static inline void pipe_truncate(struct iov_iter *i) |
987 | { | |
988 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
989 | unsigned int p_tail = pipe->tail; |
990 | unsigned int p_head = pipe->head; | |
991 | unsigned int p_mask = pipe->ring_size - 1; | |
992 | ||
993 | if (!pipe_empty(p_head, p_tail)) { | |
994 | struct pipe_buffer *buf; | |
995 | unsigned int i_head = i->head; | |
b9dc6f65 | 996 | size_t off = i->iov_offset; |
8cefc107 | 997 | |
b9dc6f65 | 998 | if (off) { |
8cefc107 DH |
999 | buf = &pipe->bufs[i_head & p_mask]; |
1000 | buf->len = off - buf->offset; | |
1001 | i_head++; | |
b9dc6f65 | 1002 | } |
8cefc107 DH |
1003 | while (p_head != i_head) { |
1004 | p_head--; | |
1005 | pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); | |
b9dc6f65 | 1006 | } |
8cefc107 DH |
1007 | |
1008 | pipe->head = p_head; | |
b9dc6f65 AV |
1009 | } |
1010 | } | |
1011 | ||
241699cd AV |
1012 | static void pipe_advance(struct iov_iter *i, size_t size) |
1013 | { | |
1014 | struct pipe_inode_info *pipe = i->pipe; | |
241699cd | 1015 | if (size) { |
b9dc6f65 | 1016 | struct pipe_buffer *buf; |
8cefc107 DH |
1017 | unsigned int p_mask = pipe->ring_size - 1; |
1018 | unsigned int i_head = i->head; | |
b9dc6f65 | 1019 | size_t off = i->iov_offset, left = size; |
8cefc107 | 1020 | |
241699cd | 1021 | if (off) /* make it relative to the beginning of buffer */ |
8cefc107 | 1022 | left += off - pipe->bufs[i_head & p_mask].offset; |
241699cd | 1023 | while (1) { |
8cefc107 | 1024 | buf = &pipe->bufs[i_head & p_mask]; |
b9dc6f65 | 1025 | if (left <= buf->len) |
241699cd | 1026 | break; |
b9dc6f65 | 1027 | left -= buf->len; |
8cefc107 | 1028 | i_head++; |
241699cd | 1029 | } |
8cefc107 | 1030 | i->head = i_head; |
b9dc6f65 | 1031 | i->iov_offset = buf->offset + left; |
241699cd | 1032 | } |
b9dc6f65 AV |
1033 | i->count -= size; |
1034 | /* ... and discard everything past that point */ | |
1035 | pipe_truncate(i); | |
241699cd AV |
1036 | } |
1037 | ||
54c8195b PB |
1038 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
1039 | { | |
1040 | struct bvec_iter bi; | |
1041 | ||
1042 | bi.bi_size = i->count; | |
1043 | bi.bi_bvec_done = i->iov_offset; | |
1044 | bi.bi_idx = 0; | |
1045 | bvec_iter_advance(i->bvec, &bi, size); | |
1046 | ||
1047 | i->bvec += bi.bi_idx; | |
1048 | i->nr_segs -= bi.bi_idx; | |
1049 | i->count = bi.bi_size; | |
1050 | i->iov_offset = bi.bi_bvec_done; | |
1051 | } | |
1052 | ||
185ac4d4 AV |
1053 | static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) |
1054 | { | |
1055 | const struct iovec *iov, *end; | |
1056 | ||
1057 | if (!i->count) | |
1058 | return; | |
1059 | i->count -= size; | |
1060 | ||
1061 | size += i->iov_offset; // from beginning of current segment | |
1062 | for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { | |
1063 | if (likely(size < iov->iov_len)) | |
1064 | break; | |
1065 | size -= iov->iov_len; | |
1066 | } | |
1067 | i->iov_offset = size; | |
1068 | i->nr_segs -= iov - i->iov; | |
1069 | i->iov = iov; | |
1070 | } | |
1071 | ||
62a8067a AV |
1072 | void iov_iter_advance(struct iov_iter *i, size_t size) |
1073 | { | |
3b3fc051 AV |
1074 | if (unlikely(i->count < size)) |
1075 | size = i->count; | |
185ac4d4 AV |
1076 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { |
1077 | /* iovec and kvec have identical layouts */ | |
1078 | iov_iter_iovec_advance(i, size); | |
1079 | } else if (iov_iter_is_bvec(i)) { | |
1080 | iov_iter_bvec_advance(i, size); | |
1081 | } else if (iov_iter_is_pipe(i)) { | |
241699cd | 1082 | pipe_advance(i, size); |
185ac4d4 | 1083 | } else if (unlikely(iov_iter_is_xarray(i))) { |
7ff50620 DH |
1084 | i->iov_offset += size; |
1085 | i->count -= size; | |
185ac4d4 AV |
1086 | } else if (iov_iter_is_discard(i)) { |
1087 | i->count -= size; | |
54c8195b | 1088 | } |
62a8067a AV |
1089 | } |
1090 | EXPORT_SYMBOL(iov_iter_advance); | |
1091 | ||
27c0e374 AV |
1092 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
1093 | { | |
1094 | if (!unroll) | |
1095 | return; | |
5b47d59a AV |
1096 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
1097 | return; | |
27c0e374 | 1098 | i->count += unroll; |
00e23707 | 1099 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 | 1100 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 DH |
1101 | unsigned int p_mask = pipe->ring_size - 1; |
1102 | unsigned int i_head = i->head; | |
27c0e374 AV |
1103 | size_t off = i->iov_offset; |
1104 | while (1) { | |
8cefc107 DH |
1105 | struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; |
1106 | size_t n = off - b->offset; | |
27c0e374 | 1107 | if (unroll < n) { |
4fa55cef | 1108 | off -= unroll; |
27c0e374 AV |
1109 | break; |
1110 | } | |
1111 | unroll -= n; | |
8cefc107 | 1112 | if (!unroll && i_head == i->start_head) { |
27c0e374 AV |
1113 | off = 0; |
1114 | break; | |
1115 | } | |
8cefc107 DH |
1116 | i_head--; |
1117 | b = &pipe->bufs[i_head & p_mask]; | |
1118 | off = b->offset + b->len; | |
27c0e374 AV |
1119 | } |
1120 | i->iov_offset = off; | |
8cefc107 | 1121 | i->head = i_head; |
27c0e374 AV |
1122 | pipe_truncate(i); |
1123 | return; | |
1124 | } | |
9ea9ce04 DH |
1125 | if (unlikely(iov_iter_is_discard(i))) |
1126 | return; | |
27c0e374 AV |
1127 | if (unroll <= i->iov_offset) { |
1128 | i->iov_offset -= unroll; | |
1129 | return; | |
1130 | } | |
1131 | unroll -= i->iov_offset; | |
7ff50620 DH |
1132 | if (iov_iter_is_xarray(i)) { |
1133 | BUG(); /* We should never go beyond the start of the specified | |
1134 | * range since we might then be straying into pages that | |
1135 | * aren't pinned. | |
1136 | */ | |
1137 | } else if (iov_iter_is_bvec(i)) { | |
27c0e374 AV |
1138 | const struct bio_vec *bvec = i->bvec; |
1139 | while (1) { | |
1140 | size_t n = (--bvec)->bv_len; | |
1141 | i->nr_segs++; | |
1142 | if (unroll <= n) { | |
1143 | i->bvec = bvec; | |
1144 | i->iov_offset = n - unroll; | |
1145 | return; | |
1146 | } | |
1147 | unroll -= n; | |
1148 | } | |
1149 | } else { /* same logics for iovec and kvec */ | |
1150 | const struct iovec *iov = i->iov; | |
1151 | while (1) { | |
1152 | size_t n = (--iov)->iov_len; | |
1153 | i->nr_segs++; | |
1154 | if (unroll <= n) { | |
1155 | i->iov = iov; | |
1156 | i->iov_offset = n - unroll; | |
1157 | return; | |
1158 | } | |
1159 | unroll -= n; | |
1160 | } | |
1161 | } | |
1162 | } | |
1163 | EXPORT_SYMBOL(iov_iter_revert); | |
1164 | ||
62a8067a AV |
1165 | /* |
1166 | * Return the count of just the current iov_iter segment. | |
1167 | */ | |
1168 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
1169 | { | |
28f38db7 AV |
1170 | if (i->nr_segs > 1) { |
1171 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1172 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
1173 | if (iov_iter_is_bvec(i)) | |
1174 | return min(i->count, i->bvec->bv_len - i->iov_offset); | |
1175 | } | |
1176 | return i->count; | |
62a8067a AV |
1177 | } |
1178 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
1179 | ||
aa563d7b | 1180 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 1181 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
1182 | size_t count) |
1183 | { | |
aa563d7b | 1184 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
1185 | *i = (struct iov_iter){ |
1186 | .iter_type = ITER_KVEC, | |
1187 | .data_source = direction, | |
1188 | .kvec = kvec, | |
1189 | .nr_segs = nr_segs, | |
1190 | .iov_offset = 0, | |
1191 | .count = count | |
1192 | }; | |
abb78f87 AV |
1193 | } |
1194 | EXPORT_SYMBOL(iov_iter_kvec); | |
1195 | ||
aa563d7b | 1196 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1197 | const struct bio_vec *bvec, unsigned long nr_segs, |
1198 | size_t count) | |
1199 | { | |
aa563d7b | 1200 | WARN_ON(direction & ~(READ | WRITE)); |
8cd54c1c AV |
1201 | *i = (struct iov_iter){ |
1202 | .iter_type = ITER_BVEC, | |
1203 | .data_source = direction, | |
1204 | .bvec = bvec, | |
1205 | .nr_segs = nr_segs, | |
1206 | .iov_offset = 0, | |
1207 | .count = count | |
1208 | }; | |
05afcb77 AV |
1209 | } |
1210 | EXPORT_SYMBOL(iov_iter_bvec); | |
1211 | ||
aa563d7b | 1212 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1213 | struct pipe_inode_info *pipe, |
1214 | size_t count) | |
1215 | { | |
aa563d7b | 1216 | BUG_ON(direction != READ); |
8cefc107 | 1217 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
8cd54c1c AV |
1218 | *i = (struct iov_iter){ |
1219 | .iter_type = ITER_PIPE, | |
1220 | .data_source = false, | |
1221 | .pipe = pipe, | |
1222 | .head = pipe->head, | |
1223 | .start_head = pipe->head, | |
1224 | .iov_offset = 0, | |
1225 | .count = count | |
1226 | }; | |
241699cd AV |
1227 | } |
1228 | EXPORT_SYMBOL(iov_iter_pipe); | |
1229 | ||
7ff50620 DH |
1230 | /** |
1231 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray | |
1232 | * @i: The iterator to initialise. | |
1233 | * @direction: The direction of the transfer. | |
1234 | * @xarray: The xarray to access. | |
1235 | * @start: The start file position. | |
1236 | * @count: The size of the I/O buffer in bytes. | |
1237 | * | |
1238 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
1239 | * inode or to inject data into those pages. The pages *must* be prevented | |
1240 | * from evaporation, either by taking a ref on them or locking them by the | |
1241 | * caller. | |
1242 | */ | |
1243 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, | |
1244 | struct xarray *xarray, loff_t start, size_t count) | |
1245 | { | |
1246 | BUG_ON(direction & ~1); | |
8cd54c1c AV |
1247 | *i = (struct iov_iter) { |
1248 | .iter_type = ITER_XARRAY, | |
1249 | .data_source = direction, | |
1250 | .xarray = xarray, | |
1251 | .xarray_start = start, | |
1252 | .count = count, | |
1253 | .iov_offset = 0 | |
1254 | }; | |
7ff50620 DH |
1255 | } |
1256 | EXPORT_SYMBOL(iov_iter_xarray); | |
1257 | ||
9ea9ce04 DH |
1258 | /** |
1259 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
1260 | * @i: The iterator to initialise. | |
1261 | * @direction: The direction of the transfer. | |
1262 | * @count: The size of the I/O buffer in bytes. | |
1263 | * | |
1264 | * Set up an I/O iterator that just discards everything that's written to it. | |
1265 | * It's only available as a READ iterator. | |
1266 | */ | |
1267 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
1268 | { | |
1269 | BUG_ON(direction != READ); | |
8cd54c1c AV |
1270 | *i = (struct iov_iter){ |
1271 | .iter_type = ITER_DISCARD, | |
1272 | .data_source = false, | |
1273 | .count = count, | |
1274 | .iov_offset = 0 | |
1275 | }; | |
9ea9ce04 DH |
1276 | } |
1277 | EXPORT_SYMBOL(iov_iter_discard); | |
1278 | ||
9221d2e3 | 1279 | static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) |
62a8067a | 1280 | { |
04a31165 AV |
1281 | unsigned long res = 0; |
1282 | size_t size = i->count; | |
9221d2e3 AV |
1283 | size_t skip = i->iov_offset; |
1284 | unsigned k; | |
1285 | ||
1286 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1287 | size_t len = i->iov[k].iov_len - skip; | |
1288 | if (len) { | |
1289 | res |= (unsigned long)i->iov[k].iov_base + skip; | |
1290 | if (len > size) | |
1291 | len = size; | |
1292 | res |= len; | |
1293 | size -= len; | |
1294 | if (!size) | |
1295 | break; | |
1296 | } | |
1297 | } | |
1298 | return res; | |
1299 | } | |
04a31165 | 1300 | |
9221d2e3 AV |
1301 | static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) |
1302 | { | |
1303 | unsigned res = 0; | |
1304 | size_t size = i->count; | |
1305 | unsigned skip = i->iov_offset; | |
1306 | unsigned k; | |
1307 | ||
1308 | for (k = 0; k < i->nr_segs; k++, skip = 0) { | |
1309 | size_t len = i->bvec[k].bv_len - skip; | |
1310 | res |= (unsigned long)i->bvec[k].bv_offset + skip; | |
1311 | if (len > size) | |
1312 | len = size; | |
1313 | res |= len; | |
1314 | size -= len; | |
1315 | if (!size) | |
1316 | break; | |
1317 | } | |
1318 | return res; | |
1319 | } | |
1320 | ||
1321 | unsigned long iov_iter_alignment(const struct iov_iter *i) | |
1322 | { | |
1323 | /* iovec and kvec have identical layouts */ | |
1324 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1325 | return iov_iter_alignment_iovec(i); | |
1326 | ||
1327 | if (iov_iter_is_bvec(i)) | |
1328 | return iov_iter_alignment_bvec(i); | |
1329 | ||
1330 | if (iov_iter_is_pipe(i)) { | |
e0ff126e | 1331 | unsigned int p_mask = i->pipe->ring_size - 1; |
9221d2e3 | 1332 | size_t size = i->count; |
e0ff126e | 1333 | |
8cefc107 | 1334 | if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) |
241699cd AV |
1335 | return size | i->iov_offset; |
1336 | return size; | |
1337 | } | |
9221d2e3 AV |
1338 | |
1339 | if (iov_iter_is_xarray(i)) | |
3d14ec1f | 1340 | return (i->xarray_start + i->iov_offset) | i->count; |
9221d2e3 AV |
1341 | |
1342 | return 0; | |
62a8067a AV |
1343 | } |
1344 | EXPORT_SYMBOL(iov_iter_alignment); | |
1345 | ||
357f435d AV |
1346 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1347 | { | |
33844e66 | 1348 | unsigned long res = 0; |
610c7a71 | 1349 | unsigned long v = 0; |
357f435d | 1350 | size_t size = i->count; |
610c7a71 | 1351 | unsigned k; |
357f435d | 1352 | |
610c7a71 | 1353 | if (WARN_ON(!iter_is_iovec(i))) |
241699cd | 1354 | return ~0U; |
241699cd | 1355 | |
610c7a71 AV |
1356 | for (k = 0; k < i->nr_segs; k++) { |
1357 | if (i->iov[k].iov_len) { | |
1358 | unsigned long base = (unsigned long)i->iov[k].iov_base; | |
1359 | if (v) // if not the first one | |
1360 | res |= base | v; // this start | previous end | |
1361 | v = base + i->iov[k].iov_len; | |
1362 | if (size <= i->iov[k].iov_len) | |
1363 | break; | |
1364 | size -= i->iov[k].iov_len; | |
1365 | } | |
1366 | } | |
33844e66 | 1367 | return res; |
357f435d AV |
1368 | } |
1369 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1370 | ||
e76b6312 | 1371 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
241699cd AV |
1372 | size_t maxsize, |
1373 | struct page **pages, | |
8cefc107 | 1374 | int iter_head, |
241699cd AV |
1375 | size_t *start) |
1376 | { | |
1377 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1378 | unsigned int p_mask = pipe->ring_size - 1; |
1379 | ssize_t n = push_pipe(i, maxsize, &iter_head, start); | |
241699cd AV |
1380 | if (!n) |
1381 | return -EFAULT; | |
1382 | ||
1383 | maxsize = n; | |
1384 | n += *start; | |
1689c73a | 1385 | while (n > 0) { |
8cefc107 DH |
1386 | get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); |
1387 | iter_head++; | |
241699cd AV |
1388 | n -= PAGE_SIZE; |
1389 | } | |
1390 | ||
1391 | return maxsize; | |
1392 | } | |
1393 | ||
1394 | static ssize_t pipe_get_pages(struct iov_iter *i, | |
1395 | struct page **pages, size_t maxsize, unsigned maxpages, | |
1396 | size_t *start) | |
1397 | { | |
8cefc107 | 1398 | unsigned int iter_head, npages; |
241699cd | 1399 | size_t capacity; |
241699cd AV |
1400 | |
1401 | if (!sanity(i)) | |
1402 | return -EFAULT; | |
1403 | ||
8cefc107 DH |
1404 | data_start(i, &iter_head, start); |
1405 | /* Amount of free space: some of this one + all after this one */ | |
1406 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
1407 | capacity = min(npages, maxpages) * PAGE_SIZE - *start; | |
241699cd | 1408 | |
8cefc107 | 1409 | return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); |
241699cd AV |
1410 | } |
1411 | ||
7ff50620 DH |
1412 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
1413 | pgoff_t index, unsigned int nr_pages) | |
1414 | { | |
1415 | XA_STATE(xas, xa, index); | |
1416 | struct page *page; | |
1417 | unsigned int ret = 0; | |
1418 | ||
1419 | rcu_read_lock(); | |
1420 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1421 | if (xas_retry(&xas, page)) | |
1422 | continue; | |
1423 | ||
1424 | /* Has the page moved or been split? */ | |
1425 | if (unlikely(page != xas_reload(&xas))) { | |
1426 | xas_reset(&xas); | |
1427 | continue; | |
1428 | } | |
1429 | ||
1430 | pages[ret] = find_subpage(page, xas.xa_index); | |
1431 | get_page(pages[ret]); | |
1432 | if (++ret == nr_pages) | |
1433 | break; | |
1434 | } | |
1435 | rcu_read_unlock(); | |
1436 | return ret; | |
1437 | } | |
1438 | ||
1439 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, | |
1440 | struct page **pages, size_t maxsize, | |
1441 | unsigned maxpages, size_t *_start_offset) | |
1442 | { | |
1443 | unsigned nr, offset; | |
1444 | pgoff_t index, count; | |
1445 | size_t size = maxsize, actual; | |
1446 | loff_t pos; | |
1447 | ||
1448 | if (!size || !maxpages) | |
1449 | return 0; | |
1450 | ||
1451 | pos = i->xarray_start + i->iov_offset; | |
1452 | index = pos >> PAGE_SHIFT; | |
1453 | offset = pos & ~PAGE_MASK; | |
1454 | *_start_offset = offset; | |
1455 | ||
1456 | count = 1; | |
1457 | if (size > PAGE_SIZE - offset) { | |
1458 | size -= PAGE_SIZE - offset; | |
1459 | count += size >> PAGE_SHIFT; | |
1460 | size &= ~PAGE_MASK; | |
1461 | if (size) | |
1462 | count++; | |
1463 | } | |
1464 | ||
1465 | if (count > maxpages) | |
1466 | count = maxpages; | |
1467 | ||
1468 | nr = iter_xarray_populate_pages(pages, i->xarray, index, count); | |
1469 | if (nr == 0) | |
1470 | return 0; | |
1471 | ||
1472 | actual = PAGE_SIZE * nr; | |
1473 | actual -= offset; | |
1474 | if (nr == count && size > 0) { | |
1475 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1476 | actual -= PAGE_SIZE - (last_offset + size); | |
1477 | } | |
1478 | return actual; | |
1479 | } | |
1480 | ||
3d671ca6 AV |
1481 | /* must be done on non-empty ITER_IOVEC one */ |
1482 | static unsigned long first_iovec_segment(const struct iov_iter *i, | |
1483 | size_t *size, size_t *start, | |
1484 | size_t maxsize, unsigned maxpages) | |
1485 | { | |
1486 | size_t skip; | |
1487 | long k; | |
1488 | ||
1489 | for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { | |
1490 | unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; | |
1491 | size_t len = i->iov[k].iov_len - skip; | |
1492 | ||
1493 | if (unlikely(!len)) | |
1494 | continue; | |
1495 | if (len > maxsize) | |
1496 | len = maxsize; | |
1497 | len += (*start = addr % PAGE_SIZE); | |
1498 | if (len > maxpages * PAGE_SIZE) | |
1499 | len = maxpages * PAGE_SIZE; | |
1500 | *size = len; | |
1501 | return addr & PAGE_MASK; | |
1502 | } | |
1503 | BUG(); // if it had been empty, we wouldn't get called | |
1504 | } | |
1505 | ||
1506 | /* must be done on non-empty ITER_BVEC one */ | |
1507 | static struct page *first_bvec_segment(const struct iov_iter *i, | |
1508 | size_t *size, size_t *start, | |
1509 | size_t maxsize, unsigned maxpages) | |
1510 | { | |
1511 | struct page *page; | |
1512 | size_t skip = i->iov_offset, len; | |
1513 | ||
1514 | len = i->bvec->bv_len - skip; | |
1515 | if (len > maxsize) | |
1516 | len = maxsize; | |
1517 | skip += i->bvec->bv_offset; | |
1518 | page = i->bvec->bv_page + skip / PAGE_SIZE; | |
1519 | len += (*start = skip % PAGE_SIZE); | |
1520 | if (len > maxpages * PAGE_SIZE) | |
1521 | len = maxpages * PAGE_SIZE; | |
1522 | *size = len; | |
1523 | return page; | |
1524 | } | |
1525 | ||
62a8067a | 1526 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
2c80929c | 1527 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
1528 | size_t *start) |
1529 | { | |
3d671ca6 AV |
1530 | size_t len; |
1531 | int n, res; | |
1532 | ||
e5393fae AV |
1533 | if (maxsize > i->count) |
1534 | maxsize = i->count; | |
3d671ca6 AV |
1535 | if (!maxsize) |
1536 | return 0; | |
e5393fae | 1537 | |
3d671ca6 AV |
1538 | if (likely(iter_is_iovec(i))) { |
1539 | unsigned long addr; | |
e5393fae | 1540 | |
3d671ca6 | 1541 | addr = first_iovec_segment(i, &len, start, maxsize, maxpages); |
e5393fae | 1542 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
73b0140b IW |
1543 | res = get_user_pages_fast(addr, n, |
1544 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, | |
1545 | pages); | |
e5393fae AV |
1546 | if (unlikely(res < 0)) |
1547 | return res; | |
1548 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
3d671ca6 AV |
1549 | } |
1550 | if (iov_iter_is_bvec(i)) { | |
1551 | struct page *page; | |
1552 | ||
1553 | page = first_bvec_segment(i, &len, start, maxsize, maxpages); | |
1554 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1555 | while (n--) | |
1556 | get_page(*pages++ = page++); | |
1557 | return len - *start; | |
1558 | } | |
1559 | if (iov_iter_is_pipe(i)) | |
1560 | return pipe_get_pages(i, pages, maxsize, maxpages, start); | |
1561 | if (iov_iter_is_xarray(i)) | |
1562 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); | |
1563 | return -EFAULT; | |
62a8067a AV |
1564 | } |
1565 | EXPORT_SYMBOL(iov_iter_get_pages); | |
1566 | ||
1b17f1f2 AV |
1567 | static struct page **get_pages_array(size_t n) |
1568 | { | |
752ade68 | 1569 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); |
1b17f1f2 AV |
1570 | } |
1571 | ||
241699cd AV |
1572 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
1573 | struct page ***pages, size_t maxsize, | |
1574 | size_t *start) | |
1575 | { | |
1576 | struct page **p; | |
8cefc107 | 1577 | unsigned int iter_head, npages; |
d7760d63 | 1578 | ssize_t n; |
241699cd AV |
1579 | |
1580 | if (!sanity(i)) | |
1581 | return -EFAULT; | |
1582 | ||
8cefc107 DH |
1583 | data_start(i, &iter_head, start); |
1584 | /* Amount of free space: some of this one + all after this one */ | |
1585 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
241699cd AV |
1586 | n = npages * PAGE_SIZE - *start; |
1587 | if (maxsize > n) | |
1588 | maxsize = n; | |
1589 | else | |
1590 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); | |
1591 | p = get_pages_array(npages); | |
1592 | if (!p) | |
1593 | return -ENOMEM; | |
8cefc107 | 1594 | n = __pipe_get_pages(i, maxsize, p, iter_head, start); |
241699cd AV |
1595 | if (n > 0) |
1596 | *pages = p; | |
1597 | else | |
1598 | kvfree(p); | |
1599 | return n; | |
1600 | } | |
1601 | ||
7ff50620 DH |
1602 | static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, |
1603 | struct page ***pages, size_t maxsize, | |
1604 | size_t *_start_offset) | |
1605 | { | |
1606 | struct page **p; | |
1607 | unsigned nr, offset; | |
1608 | pgoff_t index, count; | |
1609 | size_t size = maxsize, actual; | |
1610 | loff_t pos; | |
1611 | ||
1612 | if (!size) | |
1613 | return 0; | |
1614 | ||
1615 | pos = i->xarray_start + i->iov_offset; | |
1616 | index = pos >> PAGE_SHIFT; | |
1617 | offset = pos & ~PAGE_MASK; | |
1618 | *_start_offset = offset; | |
1619 | ||
1620 | count = 1; | |
1621 | if (size > PAGE_SIZE - offset) { | |
1622 | size -= PAGE_SIZE - offset; | |
1623 | count += size >> PAGE_SHIFT; | |
1624 | size &= ~PAGE_MASK; | |
1625 | if (size) | |
1626 | count++; | |
1627 | } | |
1628 | ||
1629 | p = get_pages_array(count); | |
1630 | if (!p) | |
1631 | return -ENOMEM; | |
1632 | *pages = p; | |
1633 | ||
1634 | nr = iter_xarray_populate_pages(p, i->xarray, index, count); | |
1635 | if (nr == 0) | |
1636 | return 0; | |
1637 | ||
1638 | actual = PAGE_SIZE * nr; | |
1639 | actual -= offset; | |
1640 | if (nr == count && size > 0) { | |
1641 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1642 | actual -= PAGE_SIZE - (last_offset + size); | |
1643 | } | |
1644 | return actual; | |
1645 | } | |
1646 | ||
62a8067a AV |
1647 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
1648 | struct page ***pages, size_t maxsize, | |
1649 | size_t *start) | |
1650 | { | |
1b17f1f2 | 1651 | struct page **p; |
3d671ca6 AV |
1652 | size_t len; |
1653 | int n, res; | |
1b17f1f2 AV |
1654 | |
1655 | if (maxsize > i->count) | |
1656 | maxsize = i->count; | |
3d671ca6 AV |
1657 | if (!maxsize) |
1658 | return 0; | |
1b17f1f2 | 1659 | |
3d671ca6 AV |
1660 | if (likely(iter_is_iovec(i))) { |
1661 | unsigned long addr; | |
1b17f1f2 | 1662 | |
3d671ca6 | 1663 | addr = first_iovec_segment(i, &len, start, maxsize, ~0U); |
1b17f1f2 AV |
1664 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
1665 | p = get_pages_array(n); | |
1666 | if (!p) | |
1667 | return -ENOMEM; | |
73b0140b IW |
1668 | res = get_user_pages_fast(addr, n, |
1669 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); | |
1b17f1f2 AV |
1670 | if (unlikely(res < 0)) { |
1671 | kvfree(p); | |
1672 | return res; | |
1673 | } | |
1674 | *pages = p; | |
1675 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
3d671ca6 AV |
1676 | } |
1677 | if (iov_iter_is_bvec(i)) { | |
1678 | struct page *page; | |
1679 | ||
1680 | page = first_bvec_segment(i, &len, start, maxsize, ~0U); | |
1681 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1682 | *pages = p = get_pages_array(n); | |
1b17f1f2 AV |
1683 | if (!p) |
1684 | return -ENOMEM; | |
3d671ca6 AV |
1685 | while (n--) |
1686 | get_page(*p++ = page++); | |
1687 | return len - *start; | |
1688 | } | |
1689 | if (iov_iter_is_pipe(i)) | |
1690 | return pipe_get_pages_alloc(i, pages, maxsize, start); | |
1691 | if (iov_iter_is_xarray(i)) | |
1692 | return iter_xarray_get_pages_alloc(i, pages, maxsize, start); | |
1693 | return -EFAULT; | |
62a8067a AV |
1694 | } |
1695 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
1696 | ||
a604ec7e AV |
1697 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1698 | struct iov_iter *i) | |
1699 | { | |
1700 | char *to = addr; | |
1701 | __wsum sum, next; | |
1702 | size_t off = 0; | |
a604ec7e | 1703 | sum = *csum; |
9ea9ce04 | 1704 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1705 | WARN_ON(1); |
1706 | return 0; | |
1707 | } | |
a604ec7e | 1708 | iterate_and_advance(i, bytes, v, ({ |
cbbd26b8 | 1709 | next = csum_and_copy_from_user(v.iov_base, |
a604ec7e | 1710 | (to += v.iov_len) - v.iov_len, |
c693cc46 AV |
1711 | v.iov_len); |
1712 | if (next) { | |
a604ec7e AV |
1713 | sum = csum_block_add(sum, next, off); |
1714 | off += v.iov_len; | |
1715 | } | |
c693cc46 | 1716 | next ? 0 : v.iov_len; |
a604ec7e AV |
1717 | }), ({ |
1718 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1719 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
1720 | p + v.bv_offset, v.bv_len, | |
1721 | sum, off); | |
a604ec7e | 1722 | kunmap_atomic(p); |
a604ec7e AV |
1723 | off += v.bv_len; |
1724 | }),({ | |
f9152895 AV |
1725 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
1726 | v.iov_base, v.iov_len, | |
1727 | sum, off); | |
a604ec7e | 1728 | off += v.iov_len; |
7ff50620 DH |
1729 | }), ({ |
1730 | char *p = kmap_atomic(v.bv_page); | |
1731 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, | |
1732 | p + v.bv_offset, v.bv_len, | |
1733 | sum, off); | |
1734 | kunmap_atomic(p); | |
1735 | off += v.bv_len; | |
a604ec7e AV |
1736 | }) |
1737 | ) | |
1738 | *csum = sum; | |
1739 | return bytes; | |
1740 | } | |
1741 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1742 | ||
52cbd23a | 1743 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
a604ec7e AV |
1744 | struct iov_iter *i) |
1745 | { | |
52cbd23a | 1746 | struct csum_state *csstate = _csstate; |
36f7a8a4 | 1747 | const char *from = addr; |
a604ec7e | 1748 | __wsum sum, next; |
52cbd23a | 1749 | size_t off; |
78e1f386 AV |
1750 | |
1751 | if (unlikely(iov_iter_is_pipe(i))) | |
52cbd23a | 1752 | return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); |
78e1f386 | 1753 | |
594e450b AV |
1754 | sum = csum_shift(csstate->csum, csstate->off); |
1755 | off = 0; | |
78e1f386 | 1756 | if (unlikely(iov_iter_is_discard(i))) { |
241699cd AV |
1757 | WARN_ON(1); /* for now */ |
1758 | return 0; | |
1759 | } | |
a604ec7e | 1760 | iterate_and_advance(i, bytes, v, ({ |
a604ec7e | 1761 | next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, |
cbbd26b8 | 1762 | v.iov_base, |
c693cc46 AV |
1763 | v.iov_len); |
1764 | if (next) { | |
a604ec7e AV |
1765 | sum = csum_block_add(sum, next, off); |
1766 | off += v.iov_len; | |
1767 | } | |
c693cc46 | 1768 | next ? 0 : v.iov_len; |
a604ec7e AV |
1769 | }), ({ |
1770 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1771 | sum = csum_and_memcpy(p + v.bv_offset, |
1772 | (from += v.bv_len) - v.bv_len, | |
1773 | v.bv_len, sum, off); | |
a604ec7e | 1774 | kunmap_atomic(p); |
a604ec7e AV |
1775 | off += v.bv_len; |
1776 | }),({ | |
f9152895 AV |
1777 | sum = csum_and_memcpy(v.iov_base, |
1778 | (from += v.iov_len) - v.iov_len, | |
1779 | v.iov_len, sum, off); | |
a604ec7e | 1780 | off += v.iov_len; |
7ff50620 DH |
1781 | }), ({ |
1782 | char *p = kmap_atomic(v.bv_page); | |
1783 | sum = csum_and_memcpy(p + v.bv_offset, | |
1784 | (from += v.bv_len) - v.bv_len, | |
1785 | v.bv_len, sum, off); | |
1786 | kunmap_atomic(p); | |
1787 | off += v.bv_len; | |
a604ec7e AV |
1788 | }) |
1789 | ) | |
594e450b AV |
1790 | csstate->csum = csum_shift(sum, csstate->off); |
1791 | csstate->off += bytes; | |
a604ec7e AV |
1792 | return bytes; |
1793 | } | |
1794 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1795 | ||
d05f4435 SG |
1796 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
1797 | struct iov_iter *i) | |
1798 | { | |
7999096f | 1799 | #ifdef CONFIG_CRYPTO_HASH |
d05f4435 SG |
1800 | struct ahash_request *hash = hashp; |
1801 | struct scatterlist sg; | |
1802 | size_t copied; | |
1803 | ||
1804 | copied = copy_to_iter(addr, bytes, i); | |
1805 | sg_init_one(&sg, addr, copied); | |
1806 | ahash_request_set_crypt(hash, &sg, NULL, copied); | |
1807 | crypto_ahash_update(hash); | |
1808 | return copied; | |
27fad74a Y |
1809 | #else |
1810 | return 0; | |
1811 | #endif | |
d05f4435 SG |
1812 | } |
1813 | EXPORT_SYMBOL(hash_and_copy_to_iter); | |
1814 | ||
66531c65 | 1815 | static int iov_npages(const struct iov_iter *i, int maxpages) |
62a8067a | 1816 | { |
66531c65 AV |
1817 | size_t skip = i->iov_offset, size = i->count; |
1818 | const struct iovec *p; | |
e0f2dc40 AV |
1819 | int npages = 0; |
1820 | ||
66531c65 AV |
1821 | for (p = i->iov; size; skip = 0, p++) { |
1822 | unsigned offs = offset_in_page(p->iov_base + skip); | |
1823 | size_t len = min(p->iov_len - skip, size); | |
e0f2dc40 | 1824 | |
66531c65 AV |
1825 | if (len) { |
1826 | size -= len; | |
1827 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1828 | if (unlikely(npages > maxpages)) | |
1829 | return maxpages; | |
1830 | } | |
1831 | } | |
1832 | return npages; | |
1833 | } | |
1834 | ||
1835 | static int bvec_npages(const struct iov_iter *i, int maxpages) | |
1836 | { | |
1837 | size_t skip = i->iov_offset, size = i->count; | |
1838 | const struct bio_vec *p; | |
1839 | int npages = 0; | |
1840 | ||
1841 | for (p = i->bvec; size; skip = 0, p++) { | |
1842 | unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; | |
1843 | size_t len = min(p->bv_len - skip, size); | |
1844 | ||
1845 | size -= len; | |
1846 | npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); | |
1847 | if (unlikely(npages > maxpages)) | |
1848 | return maxpages; | |
1849 | } | |
1850 | return npages; | |
1851 | } | |
1852 | ||
1853 | int iov_iter_npages(const struct iov_iter *i, int maxpages) | |
1854 | { | |
1855 | if (unlikely(!i->count)) | |
1856 | return 0; | |
1857 | /* iovec and kvec have identical layouts */ | |
1858 | if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) | |
1859 | return iov_npages(i, maxpages); | |
1860 | if (iov_iter_is_bvec(i)) | |
1861 | return bvec_npages(i, maxpages); | |
1862 | if (iov_iter_is_pipe(i)) { | |
8cefc107 | 1863 | unsigned int iter_head; |
66531c65 | 1864 | int npages; |
241699cd | 1865 | size_t off; |
241699cd AV |
1866 | |
1867 | if (!sanity(i)) | |
1868 | return 0; | |
1869 | ||
8cefc107 | 1870 | data_start(i, &iter_head, &off); |
241699cd | 1871 | /* some of this one + all after this one */ |
66531c65 AV |
1872 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); |
1873 | return min(npages, maxpages); | |
1874 | } | |
1875 | if (iov_iter_is_xarray(i)) { | |
e4f8df86 AV |
1876 | unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; |
1877 | int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); | |
66531c65 AV |
1878 | return min(npages, maxpages); |
1879 | } | |
1880 | return 0; | |
62a8067a | 1881 | } |
f67da30c | 1882 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1883 | |
1884 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1885 | { | |
1886 | *new = *old; | |
00e23707 | 1887 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1888 | WARN_ON(1); |
1889 | return NULL; | |
1890 | } | |
7ff50620 | 1891 | if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) |
9ea9ce04 | 1892 | return NULL; |
00e23707 | 1893 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1894 | return new->bvec = kmemdup(new->bvec, |
1895 | new->nr_segs * sizeof(struct bio_vec), | |
1896 | flags); | |
1897 | else | |
1898 | /* iovec and kvec have identical layout */ | |
1899 | return new->iov = kmemdup(new->iov, | |
1900 | new->nr_segs * sizeof(struct iovec), | |
1901 | flags); | |
1902 | } | |
1903 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1904 | |
bfdc5970 CH |
1905 | static int copy_compat_iovec_from_user(struct iovec *iov, |
1906 | const struct iovec __user *uvec, unsigned long nr_segs) | |
1907 | { | |
1908 | const struct compat_iovec __user *uiov = | |
1909 | (const struct compat_iovec __user *)uvec; | |
1910 | int ret = -EFAULT, i; | |
1911 | ||
a959a978 | 1912 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
1913 | return -EFAULT; |
1914 | ||
1915 | for (i = 0; i < nr_segs; i++) { | |
1916 | compat_uptr_t buf; | |
1917 | compat_ssize_t len; | |
1918 | ||
1919 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); | |
1920 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); | |
1921 | ||
1922 | /* check for compat_size_t not fitting in compat_ssize_t .. */ | |
1923 | if (len < 0) { | |
1924 | ret = -EINVAL; | |
1925 | goto uaccess_end; | |
1926 | } | |
1927 | iov[i].iov_base = compat_ptr(buf); | |
1928 | iov[i].iov_len = len; | |
1929 | } | |
1930 | ||
1931 | ret = 0; | |
1932 | uaccess_end: | |
1933 | user_access_end(); | |
1934 | return ret; | |
1935 | } | |
1936 | ||
1937 | static int copy_iovec_from_user(struct iovec *iov, | |
1938 | const struct iovec __user *uvec, unsigned long nr_segs) | |
fb041b59 DL |
1939 | { |
1940 | unsigned long seg; | |
fb041b59 | 1941 | |
bfdc5970 CH |
1942 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
1943 | return -EFAULT; | |
1944 | for (seg = 0; seg < nr_segs; seg++) { | |
1945 | if ((ssize_t)iov[seg].iov_len < 0) | |
1946 | return -EINVAL; | |
fb041b59 DL |
1947 | } |
1948 | ||
bfdc5970 CH |
1949 | return 0; |
1950 | } | |
1951 | ||
1952 | struct iovec *iovec_from_user(const struct iovec __user *uvec, | |
1953 | unsigned long nr_segs, unsigned long fast_segs, | |
1954 | struct iovec *fast_iov, bool compat) | |
1955 | { | |
1956 | struct iovec *iov = fast_iov; | |
1957 | int ret; | |
1958 | ||
fb041b59 | 1959 | /* |
bfdc5970 CH |
1960 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
1961 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
1962 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 1963 | */ |
bfdc5970 CH |
1964 | if (nr_segs == 0) |
1965 | return iov; | |
1966 | if (nr_segs > UIO_MAXIOV) | |
1967 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
1968 | if (nr_segs > fast_segs) { |
1969 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
1970 | if (!iov) |
1971 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 1972 | } |
bfdc5970 CH |
1973 | |
1974 | if (compat) | |
1975 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); | |
1976 | else | |
1977 | ret = copy_iovec_from_user(iov, uvec, nr_segs); | |
1978 | if (ret) { | |
1979 | if (iov != fast_iov) | |
1980 | kfree(iov); | |
1981 | return ERR_PTR(ret); | |
1982 | } | |
1983 | ||
1984 | return iov; | |
1985 | } | |
1986 | ||
1987 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
1988 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
1989 | struct iov_iter *i, bool compat) | |
1990 | { | |
1991 | ssize_t total_len = 0; | |
1992 | unsigned long seg; | |
1993 | struct iovec *iov; | |
1994 | ||
1995 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); | |
1996 | if (IS_ERR(iov)) { | |
1997 | *iovp = NULL; | |
1998 | return PTR_ERR(iov); | |
fb041b59 DL |
1999 | } |
2000 | ||
2001 | /* | |
bfdc5970 CH |
2002 | * According to the Single Unix Specification we should return EINVAL if |
2003 | * an element length is < 0 when cast to ssize_t or if the total length | |
2004 | * would overflow the ssize_t return value of the system call. | |
fb041b59 DL |
2005 | * |
2006 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
2007 | * overflow case. | |
2008 | */ | |
fb041b59 | 2009 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
2010 | ssize_t len = (ssize_t)iov[seg].iov_len; |
2011 | ||
bfdc5970 CH |
2012 | if (!access_ok(iov[seg].iov_base, len)) { |
2013 | if (iov != *iovp) | |
2014 | kfree(iov); | |
2015 | *iovp = NULL; | |
2016 | return -EFAULT; | |
fb041b59 | 2017 | } |
bfdc5970 CH |
2018 | |
2019 | if (len > MAX_RW_COUNT - total_len) { | |
2020 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
2021 | iov[seg].iov_len = len; |
2022 | } | |
bfdc5970 | 2023 | total_len += len; |
fb041b59 | 2024 | } |
bfdc5970 CH |
2025 | |
2026 | iov_iter_init(i, type, iov, nr_segs, total_len); | |
2027 | if (iov == *iovp) | |
2028 | *iovp = NULL; | |
2029 | else | |
2030 | *iovp = iov; | |
2031 | return total_len; | |
fb041b59 DL |
2032 | } |
2033 | ||
ffecee4f VN |
2034 | /** |
2035 | * import_iovec() - Copy an array of &struct iovec from userspace | |
2036 | * into the kernel, check that it is valid, and initialize a new | |
2037 | * &struct iov_iter iterator to access it. | |
2038 | * | |
2039 | * @type: One of %READ or %WRITE. | |
bfdc5970 | 2040 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
2041 | * @nr_segs: Number of elements in userspace array. |
2042 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 2043 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
2044 | * on-stack) kernel array. |
2045 | * @i: Pointer to iterator that will be initialized on success. | |
2046 | * | |
2047 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
2048 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
2049 | * array will be allocated and the result placed in *@iov. This means that | |
2050 | * the caller may call kfree() on *@iov regardless of whether the small | |
2051 | * on-stack array was used or not (and regardless of whether this function | |
2052 | * returns an error or not). | |
2053 | * | |
87e5e6da | 2054 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 2055 | */ |
bfdc5970 | 2056 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 2057 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 2058 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 2059 | { |
89cd35c5 CH |
2060 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
2061 | in_compat_syscall()); | |
bc917be8 AV |
2062 | } |
2063 | EXPORT_SYMBOL(import_iovec); | |
2064 | ||
bc917be8 AV |
2065 | int import_single_range(int rw, void __user *buf, size_t len, |
2066 | struct iovec *iov, struct iov_iter *i) | |
2067 | { | |
2068 | if (len > MAX_RW_COUNT) | |
2069 | len = MAX_RW_COUNT; | |
96d4f267 | 2070 | if (unlikely(!access_ok(buf, len))) |
bc917be8 AV |
2071 | return -EFAULT; |
2072 | ||
2073 | iov->iov_base = buf; | |
2074 | iov->iov_len = len; | |
2075 | iov_iter_init(i, rw, iov, 1, len); | |
2076 | return 0; | |
2077 | } | |
e1267585 | 2078 | EXPORT_SYMBOL(import_single_range); |