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> | |
91f79c43 AV |
8 | #include <linux/slab.h> |
9 | #include <linux/vmalloc.h> | |
241699cd | 10 | #include <linux/splice.h> |
bfdc5970 | 11 | #include <linux/compat.h> |
a604ec7e | 12 | #include <net/checksum.h> |
d05f4435 | 13 | #include <linux/scatterlist.h> |
d0ef4c36 | 14 | #include <linux/instrumented.h> |
4f18cd31 | 15 | |
241699cd AV |
16 | #define PIPE_PARANOIA /* for now */ |
17 | ||
04a31165 AV |
18 | #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ |
19 | size_t left; \ | |
20 | size_t wanted = n; \ | |
21 | __p = i->iov; \ | |
22 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
23 | if (likely(__v.iov_len)) { \ | |
24 | __v.iov_base = __p->iov_base + skip; \ | |
25 | left = (STEP); \ | |
26 | __v.iov_len -= left; \ | |
27 | skip += __v.iov_len; \ | |
28 | n -= __v.iov_len; \ | |
29 | } else { \ | |
30 | left = 0; \ | |
31 | } \ | |
32 | while (unlikely(!left && n)) { \ | |
33 | __p++; \ | |
34 | __v.iov_len = min(n, __p->iov_len); \ | |
35 | if (unlikely(!__v.iov_len)) \ | |
36 | continue; \ | |
37 | __v.iov_base = __p->iov_base; \ | |
38 | left = (STEP); \ | |
39 | __v.iov_len -= left; \ | |
40 | skip = __v.iov_len; \ | |
41 | n -= __v.iov_len; \ | |
42 | } \ | |
43 | n = wanted - n; \ | |
44 | } | |
45 | ||
a280455f AV |
46 | #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ |
47 | size_t wanted = n; \ | |
48 | __p = i->kvec; \ | |
49 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
50 | if (likely(__v.iov_len)) { \ | |
51 | __v.iov_base = __p->iov_base + skip; \ | |
52 | (void)(STEP); \ | |
53 | skip += __v.iov_len; \ | |
54 | n -= __v.iov_len; \ | |
55 | } \ | |
56 | while (unlikely(n)) { \ | |
57 | __p++; \ | |
58 | __v.iov_len = min(n, __p->iov_len); \ | |
59 | if (unlikely(!__v.iov_len)) \ | |
60 | continue; \ | |
61 | __v.iov_base = __p->iov_base; \ | |
62 | (void)(STEP); \ | |
63 | skip = __v.iov_len; \ | |
64 | n -= __v.iov_len; \ | |
65 | } \ | |
66 | n = wanted; \ | |
67 | } | |
68 | ||
1bdc76ae ML |
69 | #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ |
70 | struct bvec_iter __start; \ | |
71 | __start.bi_size = n; \ | |
72 | __start.bi_bvec_done = skip; \ | |
73 | __start.bi_idx = 0; \ | |
74 | for_each_bvec(__v, i->bvec, __bi, __start) { \ | |
04a31165 | 75 | (void)(STEP); \ |
04a31165 | 76 | } \ |
04a31165 AV |
77 | } |
78 | ||
7ff50620 DH |
79 | #define iterate_xarray(i, n, __v, skip, STEP) { \ |
80 | struct page *head = NULL; \ | |
81 | size_t wanted = n, seg, offset; \ | |
82 | loff_t start = i->xarray_start + skip; \ | |
83 | pgoff_t index = start >> PAGE_SHIFT; \ | |
84 | int j; \ | |
85 | \ | |
86 | XA_STATE(xas, i->xarray, index); \ | |
87 | \ | |
88 | rcu_read_lock(); \ | |
89 | xas_for_each(&xas, head, ULONG_MAX) { \ | |
90 | if (xas_retry(&xas, head)) \ | |
91 | continue; \ | |
92 | if (WARN_ON(xa_is_value(head))) \ | |
93 | break; \ | |
94 | if (WARN_ON(PageHuge(head))) \ | |
95 | break; \ | |
96 | for (j = (head->index < index) ? index - head->index : 0; \ | |
97 | j < thp_nr_pages(head); j++) { \ | |
98 | __v.bv_page = head + j; \ | |
99 | offset = (i->xarray_start + skip) & ~PAGE_MASK; \ | |
100 | seg = PAGE_SIZE - offset; \ | |
101 | __v.bv_offset = offset; \ | |
102 | __v.bv_len = min(n, seg); \ | |
103 | (void)(STEP); \ | |
104 | n -= __v.bv_len; \ | |
105 | skip += __v.bv_len; \ | |
106 | if (n == 0) \ | |
107 | break; \ | |
108 | } \ | |
109 | if (n == 0) \ | |
110 | break; \ | |
111 | } \ | |
112 | rcu_read_unlock(); \ | |
113 | n = wanted - n; \ | |
114 | } | |
115 | ||
116 | #define iterate_all_kinds(i, n, v, I, B, K, X) { \ | |
33844e66 AV |
117 | if (likely(n)) { \ |
118 | size_t skip = i->iov_offset; \ | |
119 | if (unlikely(i->type & ITER_BVEC)) { \ | |
120 | struct bio_vec v; \ | |
121 | struct bvec_iter __bi; \ | |
122 | iterate_bvec(i, n, v, __bi, skip, (B)) \ | |
123 | } else if (unlikely(i->type & ITER_KVEC)) { \ | |
124 | const struct kvec *kvec; \ | |
125 | struct kvec v; \ | |
126 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
9ea9ce04 | 127 | } else if (unlikely(i->type & ITER_DISCARD)) { \ |
7ff50620 DH |
128 | } else if (unlikely(i->type & ITER_XARRAY)) { \ |
129 | struct bio_vec v; \ | |
130 | iterate_xarray(i, n, v, skip, (X)); \ | |
33844e66 AV |
131 | } else { \ |
132 | const struct iovec *iov; \ | |
133 | struct iovec v; \ | |
134 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
135 | } \ | |
04a31165 AV |
136 | } \ |
137 | } | |
138 | ||
7ff50620 | 139 | #define iterate_and_advance(i, n, v, I, B, K, X) { \ |
dd254f5a AV |
140 | if (unlikely(i->count < n)) \ |
141 | n = i->count; \ | |
19f18459 | 142 | if (i->count) { \ |
dd254f5a AV |
143 | size_t skip = i->iov_offset; \ |
144 | if (unlikely(i->type & ITER_BVEC)) { \ | |
1bdc76ae | 145 | const struct bio_vec *bvec = i->bvec; \ |
dd254f5a | 146 | struct bio_vec v; \ |
1bdc76ae ML |
147 | struct bvec_iter __bi; \ |
148 | iterate_bvec(i, n, v, __bi, skip, (B)) \ | |
149 | i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ | |
150 | i->nr_segs -= i->bvec - bvec; \ | |
151 | skip = __bi.bi_bvec_done; \ | |
dd254f5a AV |
152 | } else if (unlikely(i->type & ITER_KVEC)) { \ |
153 | const struct kvec *kvec; \ | |
154 | struct kvec v; \ | |
155 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
156 | if (skip == kvec->iov_len) { \ | |
157 | kvec++; \ | |
158 | skip = 0; \ | |
159 | } \ | |
160 | i->nr_segs -= kvec - i->kvec; \ | |
161 | i->kvec = kvec; \ | |
9ea9ce04 DH |
162 | } else if (unlikely(i->type & ITER_DISCARD)) { \ |
163 | skip += n; \ | |
7ff50620 DH |
164 | } else if (unlikely(i->type & ITER_XARRAY)) { \ |
165 | struct bio_vec v; \ | |
166 | iterate_xarray(i, n, v, skip, (X)) \ | |
dd254f5a AV |
167 | } else { \ |
168 | const struct iovec *iov; \ | |
169 | struct iovec v; \ | |
170 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
171 | if (skip == iov->iov_len) { \ | |
172 | iov++; \ | |
173 | skip = 0; \ | |
174 | } \ | |
175 | i->nr_segs -= iov - i->iov; \ | |
176 | i->iov = iov; \ | |
7ce2a91e | 177 | } \ |
dd254f5a AV |
178 | i->count -= n; \ |
179 | i->iov_offset = skip; \ | |
7ce2a91e | 180 | } \ |
7ce2a91e AV |
181 | } |
182 | ||
09fc68dc AV |
183 | static int copyout(void __user *to, const void *from, size_t n) |
184 | { | |
4d0e9df5 AL |
185 | if (should_fail_usercopy()) |
186 | return n; | |
96d4f267 | 187 | if (access_ok(to, n)) { |
d0ef4c36 | 188 | instrument_copy_to_user(to, from, n); |
09fc68dc AV |
189 | n = raw_copy_to_user(to, from, n); |
190 | } | |
191 | return n; | |
192 | } | |
193 | ||
194 | static int copyin(void *to, const void __user *from, size_t n) | |
195 | { | |
4d0e9df5 AL |
196 | if (should_fail_usercopy()) |
197 | return n; | |
96d4f267 | 198 | if (access_ok(from, n)) { |
d0ef4c36 | 199 | instrument_copy_from_user(to, from, n); |
09fc68dc AV |
200 | n = raw_copy_from_user(to, from, n); |
201 | } | |
202 | return n; | |
203 | } | |
204 | ||
62a8067a | 205 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
206 | struct iov_iter *i) |
207 | { | |
208 | size_t skip, copy, left, wanted; | |
209 | const struct iovec *iov; | |
210 | char __user *buf; | |
211 | void *kaddr, *from; | |
212 | ||
213 | if (unlikely(bytes > i->count)) | |
214 | bytes = i->count; | |
215 | ||
216 | if (unlikely(!bytes)) | |
217 | return 0; | |
218 | ||
09fc68dc | 219 | might_fault(); |
4f18cd31 AV |
220 | wanted = bytes; |
221 | iov = i->iov; | |
222 | skip = i->iov_offset; | |
223 | buf = iov->iov_base + skip; | |
224 | copy = min(bytes, iov->iov_len - skip); | |
225 | ||
3fa6c507 | 226 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { |
4f18cd31 AV |
227 | kaddr = kmap_atomic(page); |
228 | from = kaddr + offset; | |
229 | ||
230 | /* first chunk, usually the only one */ | |
09fc68dc | 231 | left = copyout(buf, from, copy); |
4f18cd31 AV |
232 | copy -= left; |
233 | skip += copy; | |
234 | from += copy; | |
235 | bytes -= copy; | |
236 | ||
237 | while (unlikely(!left && bytes)) { | |
238 | iov++; | |
239 | buf = iov->iov_base; | |
240 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 241 | left = copyout(buf, from, copy); |
4f18cd31 AV |
242 | copy -= left; |
243 | skip = copy; | |
244 | from += copy; | |
245 | bytes -= copy; | |
246 | } | |
247 | if (likely(!bytes)) { | |
248 | kunmap_atomic(kaddr); | |
249 | goto done; | |
250 | } | |
251 | offset = from - kaddr; | |
252 | buf += copy; | |
253 | kunmap_atomic(kaddr); | |
254 | copy = min(bytes, iov->iov_len - skip); | |
255 | } | |
256 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 257 | |
4f18cd31 AV |
258 | kaddr = kmap(page); |
259 | from = kaddr + offset; | |
09fc68dc | 260 | left = copyout(buf, from, copy); |
4f18cd31 AV |
261 | copy -= left; |
262 | skip += copy; | |
263 | from += copy; | |
264 | bytes -= copy; | |
265 | while (unlikely(!left && bytes)) { | |
266 | iov++; | |
267 | buf = iov->iov_base; | |
268 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 269 | left = copyout(buf, from, copy); |
4f18cd31 AV |
270 | copy -= left; |
271 | skip = copy; | |
272 | from += copy; | |
273 | bytes -= copy; | |
274 | } | |
275 | kunmap(page); | |
3fa6c507 | 276 | |
4f18cd31 | 277 | done: |
81055e58 AV |
278 | if (skip == iov->iov_len) { |
279 | iov++; | |
280 | skip = 0; | |
281 | } | |
4f18cd31 AV |
282 | i->count -= wanted - bytes; |
283 | i->nr_segs -= iov - i->iov; | |
284 | i->iov = iov; | |
285 | i->iov_offset = skip; | |
286 | return wanted - bytes; | |
287 | } | |
4f18cd31 | 288 | |
62a8067a | 289 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
290 | struct iov_iter *i) |
291 | { | |
292 | size_t skip, copy, left, wanted; | |
293 | const struct iovec *iov; | |
294 | char __user *buf; | |
295 | void *kaddr, *to; | |
296 | ||
297 | if (unlikely(bytes > i->count)) | |
298 | bytes = i->count; | |
299 | ||
300 | if (unlikely(!bytes)) | |
301 | return 0; | |
302 | ||
09fc68dc | 303 | might_fault(); |
f0d1bec9 AV |
304 | wanted = bytes; |
305 | iov = i->iov; | |
306 | skip = i->iov_offset; | |
307 | buf = iov->iov_base + skip; | |
308 | copy = min(bytes, iov->iov_len - skip); | |
309 | ||
3fa6c507 | 310 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { |
f0d1bec9 AV |
311 | kaddr = kmap_atomic(page); |
312 | to = kaddr + offset; | |
313 | ||
314 | /* first chunk, usually the only one */ | |
09fc68dc | 315 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
316 | copy -= left; |
317 | skip += copy; | |
318 | to += copy; | |
319 | bytes -= copy; | |
320 | ||
321 | while (unlikely(!left && bytes)) { | |
322 | iov++; | |
323 | buf = iov->iov_base; | |
324 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 325 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
326 | copy -= left; |
327 | skip = copy; | |
328 | to += copy; | |
329 | bytes -= copy; | |
330 | } | |
331 | if (likely(!bytes)) { | |
332 | kunmap_atomic(kaddr); | |
333 | goto done; | |
334 | } | |
335 | offset = to - kaddr; | |
336 | buf += copy; | |
337 | kunmap_atomic(kaddr); | |
338 | copy = min(bytes, iov->iov_len - skip); | |
339 | } | |
340 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 341 | |
f0d1bec9 AV |
342 | kaddr = kmap(page); |
343 | to = kaddr + offset; | |
09fc68dc | 344 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
345 | copy -= left; |
346 | skip += copy; | |
347 | to += copy; | |
348 | bytes -= copy; | |
349 | while (unlikely(!left && bytes)) { | |
350 | iov++; | |
351 | buf = iov->iov_base; | |
352 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 353 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
354 | copy -= left; |
355 | skip = copy; | |
356 | to += copy; | |
357 | bytes -= copy; | |
358 | } | |
359 | kunmap(page); | |
3fa6c507 | 360 | |
f0d1bec9 | 361 | done: |
81055e58 AV |
362 | if (skip == iov->iov_len) { |
363 | iov++; | |
364 | skip = 0; | |
365 | } | |
f0d1bec9 AV |
366 | i->count -= wanted - bytes; |
367 | i->nr_segs -= iov - i->iov; | |
368 | i->iov = iov; | |
369 | i->iov_offset = skip; | |
370 | return wanted - bytes; | |
371 | } | |
f0d1bec9 | 372 | |
241699cd AV |
373 | #ifdef PIPE_PARANOIA |
374 | static bool sanity(const struct iov_iter *i) | |
375 | { | |
376 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
377 | unsigned int p_head = pipe->head; |
378 | unsigned int p_tail = pipe->tail; | |
379 | unsigned int p_mask = pipe->ring_size - 1; | |
380 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); | |
381 | unsigned int i_head = i->head; | |
382 | unsigned int idx; | |
383 | ||
241699cd AV |
384 | if (i->iov_offset) { |
385 | struct pipe_buffer *p; | |
8cefc107 | 386 | if (unlikely(p_occupancy == 0)) |
241699cd | 387 | goto Bad; // pipe must be non-empty |
8cefc107 | 388 | if (unlikely(i_head != p_head - 1)) |
241699cd AV |
389 | goto Bad; // must be at the last buffer... |
390 | ||
8cefc107 | 391 | p = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
392 | if (unlikely(p->offset + p->len != i->iov_offset)) |
393 | goto Bad; // ... at the end of segment | |
394 | } else { | |
8cefc107 | 395 | if (i_head != p_head) |
241699cd AV |
396 | goto Bad; // must be right after the last buffer |
397 | } | |
398 | return true; | |
399 | Bad: | |
8cefc107 DH |
400 | printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); |
401 | printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", | |
402 | p_head, p_tail, pipe->ring_size); | |
403 | for (idx = 0; idx < pipe->ring_size; idx++) | |
241699cd AV |
404 | printk(KERN_ERR "[%p %p %d %d]\n", |
405 | pipe->bufs[idx].ops, | |
406 | pipe->bufs[idx].page, | |
407 | pipe->bufs[idx].offset, | |
408 | pipe->bufs[idx].len); | |
409 | WARN_ON(1); | |
410 | return false; | |
411 | } | |
412 | #else | |
413 | #define sanity(i) true | |
414 | #endif | |
415 | ||
241699cd AV |
416 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
417 | struct iov_iter *i) | |
418 | { | |
419 | struct pipe_inode_info *pipe = i->pipe; | |
420 | struct pipe_buffer *buf; | |
8cefc107 DH |
421 | unsigned int p_tail = pipe->tail; |
422 | unsigned int p_mask = pipe->ring_size - 1; | |
423 | unsigned int i_head = i->head; | |
241699cd | 424 | size_t off; |
241699cd AV |
425 | |
426 | if (unlikely(bytes > i->count)) | |
427 | bytes = i->count; | |
428 | ||
429 | if (unlikely(!bytes)) | |
430 | return 0; | |
431 | ||
432 | if (!sanity(i)) | |
433 | return 0; | |
434 | ||
435 | off = i->iov_offset; | |
8cefc107 | 436 | buf = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
437 | if (off) { |
438 | if (offset == off && buf->page == page) { | |
439 | /* merge with the last one */ | |
440 | buf->len += bytes; | |
441 | i->iov_offset += bytes; | |
442 | goto out; | |
443 | } | |
8cefc107 DH |
444 | i_head++; |
445 | buf = &pipe->bufs[i_head & p_mask]; | |
241699cd | 446 | } |
6718b6f8 | 447 | if (pipe_full(i_head, p_tail, pipe->max_usage)) |
241699cd | 448 | return 0; |
8cefc107 | 449 | |
241699cd | 450 | buf->ops = &page_cache_pipe_buf_ops; |
8cefc107 DH |
451 | get_page(page); |
452 | buf->page = page; | |
241699cd AV |
453 | buf->offset = offset; |
454 | buf->len = bytes; | |
8cefc107 DH |
455 | |
456 | pipe->head = i_head + 1; | |
241699cd | 457 | i->iov_offset = offset + bytes; |
8cefc107 | 458 | i->head = i_head; |
241699cd AV |
459 | out: |
460 | i->count -= bytes; | |
461 | return bytes; | |
462 | } | |
463 | ||
171a0203 AA |
464 | /* |
465 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of | |
466 | * bytes. For each iovec, fault in each page that constitutes the iovec. | |
467 | * | |
468 | * Return 0 on success, or non-zero if the memory could not be accessed (i.e. | |
469 | * because it is an invalid address). | |
470 | */ | |
d4690f1e | 471 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) |
171a0203 AA |
472 | { |
473 | size_t skip = i->iov_offset; | |
474 | const struct iovec *iov; | |
475 | int err; | |
476 | struct iovec v; | |
477 | ||
478 | if (!(i->type & (ITER_BVEC|ITER_KVEC))) { | |
479 | iterate_iovec(i, bytes, v, iov, skip, ({ | |
4bce9f6e | 480 | err = fault_in_pages_readable(v.iov_base, v.iov_len); |
171a0203 AA |
481 | if (unlikely(err)) |
482 | return err; | |
483 | 0;})) | |
484 | } | |
485 | return 0; | |
486 | } | |
d4690f1e | 487 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
171a0203 | 488 | |
aa563d7b | 489 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
490 | const struct iovec *iov, unsigned long nr_segs, |
491 | size_t count) | |
492 | { | |
aa563d7b DH |
493 | WARN_ON(direction & ~(READ | WRITE)); |
494 | direction &= READ | WRITE; | |
495 | ||
71d8e532 | 496 | /* It will get better. Eventually... */ |
db68ce10 | 497 | if (uaccess_kernel()) { |
aa563d7b | 498 | i->type = ITER_KVEC | direction; |
a280455f AV |
499 | i->kvec = (struct kvec *)iov; |
500 | } else { | |
aa563d7b | 501 | i->type = ITER_IOVEC | direction; |
a280455f AV |
502 | i->iov = iov; |
503 | } | |
71d8e532 AV |
504 | i->nr_segs = nr_segs; |
505 | i->iov_offset = 0; | |
506 | i->count = count; | |
507 | } | |
508 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 509 | |
c35e0248 MW |
510 | static void memzero_page(struct page *page, size_t offset, size_t len) |
511 | { | |
512 | char *addr = kmap_atomic(page); | |
513 | memset(addr + offset, 0, len); | |
514 | kunmap_atomic(addr); | |
515 | } | |
516 | ||
241699cd AV |
517 | static inline bool allocated(struct pipe_buffer *buf) |
518 | { | |
519 | return buf->ops == &default_pipe_buf_ops; | |
520 | } | |
521 | ||
8cefc107 DH |
522 | static inline void data_start(const struct iov_iter *i, |
523 | unsigned int *iter_headp, size_t *offp) | |
241699cd | 524 | { |
8cefc107 DH |
525 | unsigned int p_mask = i->pipe->ring_size - 1; |
526 | unsigned int iter_head = i->head; | |
241699cd | 527 | size_t off = i->iov_offset; |
8cefc107 DH |
528 | |
529 | if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || | |
530 | off == PAGE_SIZE)) { | |
531 | iter_head++; | |
241699cd AV |
532 | off = 0; |
533 | } | |
8cefc107 | 534 | *iter_headp = iter_head; |
241699cd AV |
535 | *offp = off; |
536 | } | |
537 | ||
538 | static size_t push_pipe(struct iov_iter *i, size_t size, | |
8cefc107 | 539 | int *iter_headp, size_t *offp) |
241699cd AV |
540 | { |
541 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
542 | unsigned int p_tail = pipe->tail; |
543 | unsigned int p_mask = pipe->ring_size - 1; | |
544 | unsigned int iter_head; | |
241699cd | 545 | size_t off; |
241699cd AV |
546 | ssize_t left; |
547 | ||
548 | if (unlikely(size > i->count)) | |
549 | size = i->count; | |
550 | if (unlikely(!size)) | |
551 | return 0; | |
552 | ||
553 | left = size; | |
8cefc107 DH |
554 | data_start(i, &iter_head, &off); |
555 | *iter_headp = iter_head; | |
241699cd AV |
556 | *offp = off; |
557 | if (off) { | |
558 | left -= PAGE_SIZE - off; | |
559 | if (left <= 0) { | |
8cefc107 | 560 | pipe->bufs[iter_head & p_mask].len += size; |
241699cd AV |
561 | return size; |
562 | } | |
8cefc107 DH |
563 | pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; |
564 | iter_head++; | |
241699cd | 565 | } |
6718b6f8 | 566 | while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { |
8cefc107 | 567 | struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; |
241699cd AV |
568 | struct page *page = alloc_page(GFP_USER); |
569 | if (!page) | |
570 | break; | |
8cefc107 DH |
571 | |
572 | buf->ops = &default_pipe_buf_ops; | |
573 | buf->page = page; | |
574 | buf->offset = 0; | |
575 | buf->len = min_t(ssize_t, left, PAGE_SIZE); | |
576 | left -= buf->len; | |
577 | iter_head++; | |
578 | pipe->head = iter_head; | |
579 | ||
580 | if (left == 0) | |
241699cd | 581 | return size; |
241699cd AV |
582 | } |
583 | return size - left; | |
584 | } | |
585 | ||
586 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, | |
587 | struct iov_iter *i) | |
588 | { | |
589 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
590 | unsigned int p_mask = pipe->ring_size - 1; |
591 | unsigned int i_head; | |
241699cd | 592 | size_t n, off; |
241699cd AV |
593 | |
594 | if (!sanity(i)) | |
595 | return 0; | |
596 | ||
8cefc107 | 597 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
598 | if (unlikely(!n)) |
599 | return 0; | |
8cefc107 | 600 | do { |
241699cd | 601 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
602 | memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); |
603 | i->head = i_head; | |
241699cd AV |
604 | i->iov_offset = off + chunk; |
605 | n -= chunk; | |
606 | addr += chunk; | |
8cefc107 DH |
607 | off = 0; |
608 | i_head++; | |
609 | } while (n); | |
241699cd AV |
610 | i->count -= bytes; |
611 | return bytes; | |
612 | } | |
613 | ||
f9152895 AV |
614 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
615 | __wsum sum, size_t off) | |
616 | { | |
cc44c17b | 617 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
f9152895 AV |
618 | return csum_block_add(sum, next, off); |
619 | } | |
620 | ||
78e1f386 | 621 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
52cbd23a WB |
622 | struct csum_state *csstate, |
623 | struct iov_iter *i) | |
78e1f386 AV |
624 | { |
625 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 | 626 | unsigned int p_mask = pipe->ring_size - 1; |
52cbd23a WB |
627 | __wsum sum = csstate->csum; |
628 | size_t off = csstate->off; | |
8cefc107 | 629 | unsigned int i_head; |
78e1f386 | 630 | size_t n, r; |
78e1f386 AV |
631 | |
632 | if (!sanity(i)) | |
633 | return 0; | |
634 | ||
8cefc107 | 635 | bytes = n = push_pipe(i, bytes, &i_head, &r); |
78e1f386 AV |
636 | if (unlikely(!n)) |
637 | return 0; | |
8cefc107 | 638 | do { |
78e1f386 | 639 | size_t chunk = min_t(size_t, n, PAGE_SIZE - r); |
8cefc107 | 640 | char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); |
f9152895 | 641 | sum = csum_and_memcpy(p + r, addr, chunk, sum, off); |
78e1f386 | 642 | kunmap_atomic(p); |
8cefc107 | 643 | i->head = i_head; |
78e1f386 AV |
644 | i->iov_offset = r + chunk; |
645 | n -= chunk; | |
646 | off += chunk; | |
647 | addr += chunk; | |
8cefc107 DH |
648 | r = 0; |
649 | i_head++; | |
650 | } while (n); | |
78e1f386 | 651 | i->count -= bytes; |
52cbd23a WB |
652 | csstate->csum = sum; |
653 | csstate->off = off; | |
78e1f386 AV |
654 | return bytes; |
655 | } | |
656 | ||
aa28de27 | 657 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 658 | { |
36f7a8a4 | 659 | const char *from = addr; |
00e23707 | 660 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 661 | return copy_pipe_to_iter(addr, bytes, i); |
09fc68dc AV |
662 | if (iter_is_iovec(i)) |
663 | might_fault(); | |
3d4d3e48 | 664 | iterate_and_advance(i, bytes, v, |
09fc68dc | 665 | copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
3d4d3e48 | 666 | memcpy_to_page(v.bv_page, v.bv_offset, |
a280455f | 667 | (from += v.bv_len) - v.bv_len, v.bv_len), |
7ff50620 DH |
668 | memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
669 | memcpy_to_page(v.bv_page, v.bv_offset, | |
670 | (from += v.bv_len) - v.bv_len, v.bv_len) | |
3d4d3e48 | 671 | ) |
62a8067a | 672 | |
3d4d3e48 | 673 | return bytes; |
c35e0248 | 674 | } |
aa28de27 | 675 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 676 | |
ec6347bb DW |
677 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
678 | static int copyout_mc(void __user *to, const void *from, size_t n) | |
8780356e | 679 | { |
96d4f267 | 680 | if (access_ok(to, n)) { |
d0ef4c36 | 681 | instrument_copy_to_user(to, from, n); |
ec6347bb | 682 | n = copy_mc_to_user((__force void *) to, from, n); |
8780356e DW |
683 | } |
684 | return n; | |
685 | } | |
686 | ||
ec6347bb | 687 | static unsigned long copy_mc_to_page(struct page *page, size_t offset, |
8780356e DW |
688 | const char *from, size_t len) |
689 | { | |
690 | unsigned long ret; | |
691 | char *to; | |
692 | ||
693 | to = kmap_atomic(page); | |
ec6347bb | 694 | ret = copy_mc_to_kernel(to + offset, from, len); |
8780356e DW |
695 | kunmap_atomic(to); |
696 | ||
697 | return ret; | |
698 | } | |
699 | ||
ec6347bb | 700 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
ca146f6f DW |
701 | struct iov_iter *i) |
702 | { | |
703 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
704 | unsigned int p_mask = pipe->ring_size - 1; |
705 | unsigned int i_head; | |
ca146f6f | 706 | size_t n, off, xfer = 0; |
ca146f6f DW |
707 | |
708 | if (!sanity(i)) | |
709 | return 0; | |
710 | ||
8cefc107 | 711 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
ca146f6f DW |
712 | if (unlikely(!n)) |
713 | return 0; | |
8cefc107 | 714 | do { |
ca146f6f DW |
715 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
716 | unsigned long rem; | |
717 | ||
ec6347bb | 718 | rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, |
8cefc107 DH |
719 | off, addr, chunk); |
720 | i->head = i_head; | |
ca146f6f DW |
721 | i->iov_offset = off + chunk - rem; |
722 | xfer += chunk - rem; | |
723 | if (rem) | |
724 | break; | |
725 | n -= chunk; | |
726 | addr += chunk; | |
8cefc107 DH |
727 | off = 0; |
728 | i_head++; | |
729 | } while (n); | |
ca146f6f DW |
730 | i->count -= xfer; |
731 | return xfer; | |
732 | } | |
733 | ||
bf3eeb9b | 734 | /** |
ec6347bb | 735 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
bf3eeb9b DW |
736 | * @addr: source kernel address |
737 | * @bytes: total transfer length | |
738 | * @iter: destination iterator | |
739 | * | |
ec6347bb DW |
740 | * The pmem driver deploys this for the dax operation |
741 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the | |
742 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes | |
743 | * successfully copied. | |
bf3eeb9b | 744 | * |
ec6347bb | 745 | * The main differences between this and typical _copy_to_iter(). |
bf3eeb9b DW |
746 | * |
747 | * * Typical tail/residue handling after a fault retries the copy | |
748 | * byte-by-byte until the fault happens again. Re-triggering machine | |
749 | * checks is potentially fatal so the implementation uses source | |
750 | * alignment and poison alignment assumptions to avoid re-triggering | |
751 | * hardware exceptions. | |
752 | * | |
753 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. | |
754 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return | |
755 | * a short copy. | |
bf3eeb9b | 756 | */ |
ec6347bb | 757 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
8780356e DW |
758 | { |
759 | const char *from = addr; | |
760 | unsigned long rem, curr_addr, s_addr = (unsigned long) addr; | |
761 | ||
00e23707 | 762 | if (unlikely(iov_iter_is_pipe(i))) |
ec6347bb | 763 | return copy_mc_pipe_to_iter(addr, bytes, i); |
8780356e DW |
764 | if (iter_is_iovec(i)) |
765 | might_fault(); | |
766 | iterate_and_advance(i, bytes, v, | |
ec6347bb DW |
767 | copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, |
768 | v.iov_len), | |
8780356e | 769 | ({ |
ec6347bb DW |
770 | rem = copy_mc_to_page(v.bv_page, v.bv_offset, |
771 | (from += v.bv_len) - v.bv_len, v.bv_len); | |
8780356e DW |
772 | if (rem) { |
773 | curr_addr = (unsigned long) from; | |
774 | bytes = curr_addr - s_addr - rem; | |
775 | return bytes; | |
776 | } | |
777 | }), | |
778 | ({ | |
ec6347bb DW |
779 | rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) |
780 | - v.iov_len, v.iov_len); | |
8780356e DW |
781 | if (rem) { |
782 | curr_addr = (unsigned long) from; | |
783 | bytes = curr_addr - s_addr - rem; | |
784 | return bytes; | |
785 | } | |
7ff50620 DH |
786 | }), |
787 | ({ | |
788 | rem = copy_mc_to_page(v.bv_page, v.bv_offset, | |
789 | (from += v.bv_len) - v.bv_len, v.bv_len); | |
790 | if (rem) { | |
791 | curr_addr = (unsigned long) from; | |
792 | bytes = curr_addr - s_addr - rem; | |
793 | rcu_read_unlock(); | |
3d14ec1f DH |
794 | i->iov_offset += bytes; |
795 | i->count -= bytes; | |
7ff50620 DH |
796 | return bytes; |
797 | } | |
8780356e DW |
798 | }) |
799 | ) | |
800 | ||
801 | return bytes; | |
802 | } | |
ec6347bb DW |
803 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
804 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 805 | |
aa28de27 | 806 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 807 | { |
0dbca9a4 | 808 | char *to = addr; |
00e23707 | 809 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
810 | WARN_ON(1); |
811 | return 0; | |
812 | } | |
09fc68dc AV |
813 | if (iter_is_iovec(i)) |
814 | might_fault(); | |
0dbca9a4 | 815 | iterate_and_advance(i, bytes, v, |
09fc68dc | 816 | copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
0dbca9a4 | 817 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 818 | v.bv_offset, v.bv_len), |
7ff50620 DH |
819 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
820 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
821 | v.bv_offset, v.bv_len) | |
0dbca9a4 AV |
822 | ) |
823 | ||
824 | return bytes; | |
c35e0248 | 825 | } |
aa28de27 | 826 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 827 | |
aa28de27 | 828 | bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) |
cbbd26b8 AV |
829 | { |
830 | char *to = addr; | |
00e23707 | 831 | if (unlikely(iov_iter_is_pipe(i))) { |
cbbd26b8 AV |
832 | WARN_ON(1); |
833 | return false; | |
834 | } | |
33844e66 | 835 | if (unlikely(i->count < bytes)) |
cbbd26b8 AV |
836 | return false; |
837 | ||
09fc68dc AV |
838 | if (iter_is_iovec(i)) |
839 | might_fault(); | |
cbbd26b8 | 840 | iterate_all_kinds(i, bytes, v, ({ |
09fc68dc | 841 | if (copyin((to += v.iov_len) - v.iov_len, |
cbbd26b8 AV |
842 | v.iov_base, v.iov_len)) |
843 | return false; | |
844 | 0;}), | |
845 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
846 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
847 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
848 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
849 | v.bv_offset, v.bv_len) | |
cbbd26b8 AV |
850 | ) |
851 | ||
852 | iov_iter_advance(i, bytes); | |
853 | return true; | |
854 | } | |
aa28de27 | 855 | EXPORT_SYMBOL(_copy_from_iter_full); |
cbbd26b8 | 856 | |
aa28de27 | 857 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 AV |
858 | { |
859 | char *to = addr; | |
00e23707 | 860 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
861 | WARN_ON(1); |
862 | return 0; | |
863 | } | |
aa583096 | 864 | iterate_and_advance(i, bytes, v, |
3f763453 | 865 | __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
aa583096 AV |
866 | v.iov_base, v.iov_len), |
867 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
868 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
869 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
870 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
871 | v.bv_offset, v.bv_len) | |
aa583096 AV |
872 | ) |
873 | ||
874 | return bytes; | |
875 | } | |
aa28de27 | 876 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 877 | |
0aed55af | 878 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
879 | /** |
880 | * _copy_from_iter_flushcache - write destination through cpu cache | |
881 | * @addr: destination kernel address | |
882 | * @bytes: total transfer length | |
883 | * @iter: source iterator | |
884 | * | |
885 | * The pmem driver arranges for filesystem-dax to use this facility via | |
886 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
887 | * are flushed through the CPU cache. It is differentiated from | |
888 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
889 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
890 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
891 | * instructions that strand dirty-data in the cache. | |
892 | */ | |
6a37e940 | 893 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af DW |
894 | { |
895 | char *to = addr; | |
00e23707 | 896 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
897 | WARN_ON(1); |
898 | return 0; | |
899 | } | |
900 | iterate_and_advance(i, bytes, v, | |
901 | __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, | |
902 | v.iov_base, v.iov_len), | |
903 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
904 | v.bv_offset, v.bv_len), | |
905 | memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, | |
7ff50620 DH |
906 | v.iov_len), |
907 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
908 | v.bv_offset, v.bv_len) | |
0aed55af DW |
909 | ) |
910 | ||
911 | return bytes; | |
912 | } | |
6a37e940 | 913 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
914 | #endif |
915 | ||
aa28de27 | 916 | bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) |
cbbd26b8 AV |
917 | { |
918 | char *to = addr; | |
00e23707 | 919 | if (unlikely(iov_iter_is_pipe(i))) { |
cbbd26b8 AV |
920 | WARN_ON(1); |
921 | return false; | |
922 | } | |
33844e66 | 923 | if (unlikely(i->count < bytes)) |
cbbd26b8 AV |
924 | return false; |
925 | iterate_all_kinds(i, bytes, v, ({ | |
3f763453 | 926 | if (__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
cbbd26b8 AV |
927 | v.iov_base, v.iov_len)) |
928 | return false; | |
929 | 0;}), | |
930 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
931 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
932 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
933 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
934 | v.bv_offset, v.bv_len) | |
cbbd26b8 AV |
935 | ) |
936 | ||
937 | iov_iter_advance(i, bytes); | |
938 | return true; | |
939 | } | |
aa28de27 | 940 | EXPORT_SYMBOL(_copy_from_iter_full_nocache); |
cbbd26b8 | 941 | |
72e809ed AV |
942 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
943 | { | |
6daef95b ED |
944 | struct page *head; |
945 | size_t v = n + offset; | |
946 | ||
947 | /* | |
948 | * The general case needs to access the page order in order | |
949 | * to compute the page size. | |
950 | * However, we mostly deal with order-0 pages and thus can | |
951 | * avoid a possible cache line miss for requests that fit all | |
952 | * page orders. | |
953 | */ | |
954 | if (n <= v && v <= PAGE_SIZE) | |
955 | return true; | |
956 | ||
957 | head = compound_head(page); | |
958 | v += (page - head) << PAGE_SHIFT; | |
a90bcb86 | 959 | |
a50b854e | 960 | if (likely(n <= v && v <= (page_size(head)))) |
72e809ed AV |
961 | return true; |
962 | WARN_ON(1); | |
963 | return false; | |
964 | } | |
cbbd26b8 | 965 | |
62a8067a AV |
966 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
967 | struct iov_iter *i) | |
968 | { | |
72e809ed AV |
969 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
970 | return 0; | |
7ff50620 | 971 | if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { |
d271524a AV |
972 | void *kaddr = kmap_atomic(page); |
973 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); | |
974 | kunmap_atomic(kaddr); | |
975 | return wanted; | |
9ea9ce04 DH |
976 | } else if (unlikely(iov_iter_is_discard(i))) |
977 | return bytes; | |
978 | else if (likely(!iov_iter_is_pipe(i))) | |
62a8067a | 979 | return copy_page_to_iter_iovec(page, offset, bytes, i); |
241699cd AV |
980 | else |
981 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
62a8067a AV |
982 | } |
983 | EXPORT_SYMBOL(copy_page_to_iter); | |
984 | ||
985 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
986 | struct iov_iter *i) | |
987 | { | |
72e809ed AV |
988 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
989 | return 0; | |
9ea9ce04 | 990 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
991 | WARN_ON(1); |
992 | return 0; | |
993 | } | |
7ff50620 | 994 | if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { |
d271524a | 995 | void *kaddr = kmap_atomic(page); |
aa28de27 | 996 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
d271524a AV |
997 | kunmap_atomic(kaddr); |
998 | return wanted; | |
999 | } else | |
62a8067a AV |
1000 | return copy_page_from_iter_iovec(page, offset, bytes, i); |
1001 | } | |
1002 | EXPORT_SYMBOL(copy_page_from_iter); | |
1003 | ||
241699cd AV |
1004 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
1005 | { | |
1006 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1007 | unsigned int p_mask = pipe->ring_size - 1; |
1008 | unsigned int i_head; | |
241699cd | 1009 | size_t n, off; |
241699cd AV |
1010 | |
1011 | if (!sanity(i)) | |
1012 | return 0; | |
1013 | ||
8cefc107 | 1014 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
1015 | if (unlikely(!n)) |
1016 | return 0; | |
1017 | ||
8cefc107 | 1018 | do { |
241699cd | 1019 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
1020 | memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); |
1021 | i->head = i_head; | |
241699cd AV |
1022 | i->iov_offset = off + chunk; |
1023 | n -= chunk; | |
8cefc107 DH |
1024 | off = 0; |
1025 | i_head++; | |
1026 | } while (n); | |
241699cd AV |
1027 | i->count -= bytes; |
1028 | return bytes; | |
1029 | } | |
1030 | ||
c35e0248 MW |
1031 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
1032 | { | |
00e23707 | 1033 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1034 | return pipe_zero(bytes, i); |
8442fa46 | 1035 | iterate_and_advance(i, bytes, v, |
09fc68dc | 1036 | clear_user(v.iov_base, v.iov_len), |
a280455f | 1037 | memzero_page(v.bv_page, v.bv_offset, v.bv_len), |
7ff50620 DH |
1038 | memset(v.iov_base, 0, v.iov_len), |
1039 | memzero_page(v.bv_page, v.bv_offset, v.bv_len) | |
8442fa46 AV |
1040 | ) |
1041 | ||
1042 | return bytes; | |
c35e0248 MW |
1043 | } |
1044 | EXPORT_SYMBOL(iov_iter_zero); | |
1045 | ||
62a8067a AV |
1046 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
1047 | struct iov_iter *i, unsigned long offset, size_t bytes) | |
1048 | { | |
04a31165 | 1049 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
1050 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
1051 | kunmap_atomic(kaddr); | |
1052 | return 0; | |
1053 | } | |
9ea9ce04 | 1054 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1055 | kunmap_atomic(kaddr); |
1056 | WARN_ON(1); | |
1057 | return 0; | |
1058 | } | |
04a31165 | 1059 | iterate_all_kinds(i, bytes, v, |
09fc68dc | 1060 | copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
04a31165 | 1061 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 1062 | v.bv_offset, v.bv_len), |
7ff50620 DH |
1063 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
1064 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, | |
1065 | v.bv_offset, v.bv_len) | |
04a31165 AV |
1066 | ) |
1067 | kunmap_atomic(kaddr); | |
1068 | return bytes; | |
62a8067a AV |
1069 | } |
1070 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); | |
1071 | ||
b9dc6f65 AV |
1072 | static inline void pipe_truncate(struct iov_iter *i) |
1073 | { | |
1074 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1075 | unsigned int p_tail = pipe->tail; |
1076 | unsigned int p_head = pipe->head; | |
1077 | unsigned int p_mask = pipe->ring_size - 1; | |
1078 | ||
1079 | if (!pipe_empty(p_head, p_tail)) { | |
1080 | struct pipe_buffer *buf; | |
1081 | unsigned int i_head = i->head; | |
b9dc6f65 | 1082 | size_t off = i->iov_offset; |
8cefc107 | 1083 | |
b9dc6f65 | 1084 | if (off) { |
8cefc107 DH |
1085 | buf = &pipe->bufs[i_head & p_mask]; |
1086 | buf->len = off - buf->offset; | |
1087 | i_head++; | |
b9dc6f65 | 1088 | } |
8cefc107 DH |
1089 | while (p_head != i_head) { |
1090 | p_head--; | |
1091 | pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); | |
b9dc6f65 | 1092 | } |
8cefc107 DH |
1093 | |
1094 | pipe->head = p_head; | |
b9dc6f65 AV |
1095 | } |
1096 | } | |
1097 | ||
241699cd AV |
1098 | static void pipe_advance(struct iov_iter *i, size_t size) |
1099 | { | |
1100 | struct pipe_inode_info *pipe = i->pipe; | |
241699cd AV |
1101 | if (unlikely(i->count < size)) |
1102 | size = i->count; | |
241699cd | 1103 | if (size) { |
b9dc6f65 | 1104 | struct pipe_buffer *buf; |
8cefc107 DH |
1105 | unsigned int p_mask = pipe->ring_size - 1; |
1106 | unsigned int i_head = i->head; | |
b9dc6f65 | 1107 | size_t off = i->iov_offset, left = size; |
8cefc107 | 1108 | |
241699cd | 1109 | if (off) /* make it relative to the beginning of buffer */ |
8cefc107 | 1110 | left += off - pipe->bufs[i_head & p_mask].offset; |
241699cd | 1111 | while (1) { |
8cefc107 | 1112 | buf = &pipe->bufs[i_head & p_mask]; |
b9dc6f65 | 1113 | if (left <= buf->len) |
241699cd | 1114 | break; |
b9dc6f65 | 1115 | left -= buf->len; |
8cefc107 | 1116 | i_head++; |
241699cd | 1117 | } |
8cefc107 | 1118 | i->head = i_head; |
b9dc6f65 | 1119 | i->iov_offset = buf->offset + left; |
241699cd | 1120 | } |
b9dc6f65 AV |
1121 | i->count -= size; |
1122 | /* ... and discard everything past that point */ | |
1123 | pipe_truncate(i); | |
241699cd AV |
1124 | } |
1125 | ||
54c8195b PB |
1126 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
1127 | { | |
1128 | struct bvec_iter bi; | |
1129 | ||
1130 | bi.bi_size = i->count; | |
1131 | bi.bi_bvec_done = i->iov_offset; | |
1132 | bi.bi_idx = 0; | |
1133 | bvec_iter_advance(i->bvec, &bi, size); | |
1134 | ||
1135 | i->bvec += bi.bi_idx; | |
1136 | i->nr_segs -= bi.bi_idx; | |
1137 | i->count = bi.bi_size; | |
1138 | i->iov_offset = bi.bi_bvec_done; | |
1139 | } | |
1140 | ||
62a8067a AV |
1141 | void iov_iter_advance(struct iov_iter *i, size_t size) |
1142 | { | |
00e23707 | 1143 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
1144 | pipe_advance(i, size); |
1145 | return; | |
1146 | } | |
9ea9ce04 DH |
1147 | if (unlikely(iov_iter_is_discard(i))) { |
1148 | i->count -= size; | |
1149 | return; | |
1150 | } | |
7ff50620 | 1151 | if (unlikely(iov_iter_is_xarray(i))) { |
3d14ec1f | 1152 | size = min(size, i->count); |
7ff50620 DH |
1153 | i->iov_offset += size; |
1154 | i->count -= size; | |
1155 | return; | |
1156 | } | |
54c8195b PB |
1157 | if (iov_iter_is_bvec(i)) { |
1158 | iov_iter_bvec_advance(i, size); | |
1159 | return; | |
1160 | } | |
7ff50620 | 1161 | iterate_and_advance(i, size, v, 0, 0, 0, 0) |
62a8067a AV |
1162 | } |
1163 | EXPORT_SYMBOL(iov_iter_advance); | |
1164 | ||
27c0e374 AV |
1165 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
1166 | { | |
1167 | if (!unroll) | |
1168 | return; | |
5b47d59a AV |
1169 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
1170 | return; | |
27c0e374 | 1171 | i->count += unroll; |
00e23707 | 1172 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 | 1173 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 DH |
1174 | unsigned int p_mask = pipe->ring_size - 1; |
1175 | unsigned int i_head = i->head; | |
27c0e374 AV |
1176 | size_t off = i->iov_offset; |
1177 | while (1) { | |
8cefc107 DH |
1178 | struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; |
1179 | size_t n = off - b->offset; | |
27c0e374 | 1180 | if (unroll < n) { |
4fa55cef | 1181 | off -= unroll; |
27c0e374 AV |
1182 | break; |
1183 | } | |
1184 | unroll -= n; | |
8cefc107 | 1185 | if (!unroll && i_head == i->start_head) { |
27c0e374 AV |
1186 | off = 0; |
1187 | break; | |
1188 | } | |
8cefc107 DH |
1189 | i_head--; |
1190 | b = &pipe->bufs[i_head & p_mask]; | |
1191 | off = b->offset + b->len; | |
27c0e374 AV |
1192 | } |
1193 | i->iov_offset = off; | |
8cefc107 | 1194 | i->head = i_head; |
27c0e374 AV |
1195 | pipe_truncate(i); |
1196 | return; | |
1197 | } | |
9ea9ce04 DH |
1198 | if (unlikely(iov_iter_is_discard(i))) |
1199 | return; | |
27c0e374 AV |
1200 | if (unroll <= i->iov_offset) { |
1201 | i->iov_offset -= unroll; | |
1202 | return; | |
1203 | } | |
1204 | unroll -= i->iov_offset; | |
7ff50620 DH |
1205 | if (iov_iter_is_xarray(i)) { |
1206 | BUG(); /* We should never go beyond the start of the specified | |
1207 | * range since we might then be straying into pages that | |
1208 | * aren't pinned. | |
1209 | */ | |
1210 | } else if (iov_iter_is_bvec(i)) { | |
27c0e374 AV |
1211 | const struct bio_vec *bvec = i->bvec; |
1212 | while (1) { | |
1213 | size_t n = (--bvec)->bv_len; | |
1214 | i->nr_segs++; | |
1215 | if (unroll <= n) { | |
1216 | i->bvec = bvec; | |
1217 | i->iov_offset = n - unroll; | |
1218 | return; | |
1219 | } | |
1220 | unroll -= n; | |
1221 | } | |
1222 | } else { /* same logics for iovec and kvec */ | |
1223 | const struct iovec *iov = i->iov; | |
1224 | while (1) { | |
1225 | size_t n = (--iov)->iov_len; | |
1226 | i->nr_segs++; | |
1227 | if (unroll <= n) { | |
1228 | i->iov = iov; | |
1229 | i->iov_offset = n - unroll; | |
1230 | return; | |
1231 | } | |
1232 | unroll -= n; | |
1233 | } | |
1234 | } | |
1235 | } | |
1236 | EXPORT_SYMBOL(iov_iter_revert); | |
1237 | ||
62a8067a AV |
1238 | /* |
1239 | * Return the count of just the current iov_iter segment. | |
1240 | */ | |
1241 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
1242 | { | |
00e23707 | 1243 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1244 | return i->count; // it is a silly place, anyway |
62a8067a AV |
1245 | if (i->nr_segs == 1) |
1246 | return i->count; | |
7ff50620 | 1247 | if (unlikely(iov_iter_is_discard(i) || iov_iter_is_xarray(i))) |
9ea9ce04 | 1248 | return i->count; |
7ff50620 | 1249 | if (iov_iter_is_bvec(i)) |
62a8067a | 1250 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
ad0eab92 PM |
1251 | else |
1252 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
62a8067a AV |
1253 | } |
1254 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
1255 | ||
aa563d7b | 1256 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 1257 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
1258 | size_t count) |
1259 | { | |
aa563d7b DH |
1260 | WARN_ON(direction & ~(READ | WRITE)); |
1261 | i->type = ITER_KVEC | (direction & (READ | WRITE)); | |
05afcb77 | 1262 | i->kvec = kvec; |
abb78f87 AV |
1263 | i->nr_segs = nr_segs; |
1264 | i->iov_offset = 0; | |
1265 | i->count = count; | |
1266 | } | |
1267 | EXPORT_SYMBOL(iov_iter_kvec); | |
1268 | ||
aa563d7b | 1269 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1270 | const struct bio_vec *bvec, unsigned long nr_segs, |
1271 | size_t count) | |
1272 | { | |
aa563d7b DH |
1273 | WARN_ON(direction & ~(READ | WRITE)); |
1274 | i->type = ITER_BVEC | (direction & (READ | WRITE)); | |
05afcb77 AV |
1275 | i->bvec = bvec; |
1276 | i->nr_segs = nr_segs; | |
1277 | i->iov_offset = 0; | |
1278 | i->count = count; | |
1279 | } | |
1280 | EXPORT_SYMBOL(iov_iter_bvec); | |
1281 | ||
aa563d7b | 1282 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1283 | struct pipe_inode_info *pipe, |
1284 | size_t count) | |
1285 | { | |
aa563d7b | 1286 | BUG_ON(direction != READ); |
8cefc107 | 1287 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
aa563d7b | 1288 | i->type = ITER_PIPE | READ; |
241699cd | 1289 | i->pipe = pipe; |
8cefc107 | 1290 | i->head = pipe->head; |
241699cd AV |
1291 | i->iov_offset = 0; |
1292 | i->count = count; | |
8cefc107 | 1293 | i->start_head = i->head; |
241699cd AV |
1294 | } |
1295 | EXPORT_SYMBOL(iov_iter_pipe); | |
1296 | ||
7ff50620 DH |
1297 | /** |
1298 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray | |
1299 | * @i: The iterator to initialise. | |
1300 | * @direction: The direction of the transfer. | |
1301 | * @xarray: The xarray to access. | |
1302 | * @start: The start file position. | |
1303 | * @count: The size of the I/O buffer in bytes. | |
1304 | * | |
1305 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
1306 | * inode or to inject data into those pages. The pages *must* be prevented | |
1307 | * from evaporation, either by taking a ref on them or locking them by the | |
1308 | * caller. | |
1309 | */ | |
1310 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, | |
1311 | struct xarray *xarray, loff_t start, size_t count) | |
1312 | { | |
1313 | BUG_ON(direction & ~1); | |
1314 | i->type = ITER_XARRAY | (direction & (READ | WRITE)); | |
1315 | i->xarray = xarray; | |
1316 | i->xarray_start = start; | |
1317 | i->count = count; | |
1318 | i->iov_offset = 0; | |
1319 | } | |
1320 | EXPORT_SYMBOL(iov_iter_xarray); | |
1321 | ||
9ea9ce04 DH |
1322 | /** |
1323 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
1324 | * @i: The iterator to initialise. | |
1325 | * @direction: The direction of the transfer. | |
1326 | * @count: The size of the I/O buffer in bytes. | |
1327 | * | |
1328 | * Set up an I/O iterator that just discards everything that's written to it. | |
1329 | * It's only available as a READ iterator. | |
1330 | */ | |
1331 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
1332 | { | |
1333 | BUG_ON(direction != READ); | |
1334 | i->type = ITER_DISCARD | READ; | |
1335 | i->count = count; | |
1336 | i->iov_offset = 0; | |
1337 | } | |
1338 | EXPORT_SYMBOL(iov_iter_discard); | |
1339 | ||
62a8067a AV |
1340 | unsigned long iov_iter_alignment(const struct iov_iter *i) |
1341 | { | |
04a31165 AV |
1342 | unsigned long res = 0; |
1343 | size_t size = i->count; | |
1344 | ||
00e23707 | 1345 | if (unlikely(iov_iter_is_pipe(i))) { |
e0ff126e JK |
1346 | unsigned int p_mask = i->pipe->ring_size - 1; |
1347 | ||
8cefc107 | 1348 | if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) |
241699cd AV |
1349 | return size | i->iov_offset; |
1350 | return size; | |
1351 | } | |
3d14ec1f DH |
1352 | if (unlikely(iov_iter_is_xarray(i))) |
1353 | return (i->xarray_start + i->iov_offset) | i->count; | |
04a31165 AV |
1354 | iterate_all_kinds(i, size, v, |
1355 | (res |= (unsigned long)v.iov_base | v.iov_len, 0), | |
a280455f | 1356 | res |= v.bv_offset | v.bv_len, |
7ff50620 DH |
1357 | res |= (unsigned long)v.iov_base | v.iov_len, |
1358 | res |= v.bv_offset | v.bv_len | |
04a31165 AV |
1359 | ) |
1360 | return res; | |
62a8067a AV |
1361 | } |
1362 | EXPORT_SYMBOL(iov_iter_alignment); | |
1363 | ||
357f435d AV |
1364 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1365 | { | |
33844e66 | 1366 | unsigned long res = 0; |
357f435d | 1367 | size_t size = i->count; |
357f435d | 1368 | |
9ea9ce04 | 1369 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1370 | WARN_ON(1); |
1371 | return ~0U; | |
1372 | } | |
1373 | ||
357f435d AV |
1374 | iterate_all_kinds(i, size, v, |
1375 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | | |
1376 | (size != v.iov_len ? size : 0), 0), | |
1377 | (res |= (!res ? 0 : (unsigned long)v.bv_offset) | | |
1378 | (size != v.bv_len ? size : 0)), | |
1379 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | | |
7ff50620 DH |
1380 | (size != v.iov_len ? size : 0)), |
1381 | (res |= (!res ? 0 : (unsigned long)v.bv_offset) | | |
1382 | (size != v.bv_len ? size : 0)) | |
357f435d | 1383 | ); |
33844e66 | 1384 | return res; |
357f435d AV |
1385 | } |
1386 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1387 | ||
e76b6312 | 1388 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
241699cd AV |
1389 | size_t maxsize, |
1390 | struct page **pages, | |
8cefc107 | 1391 | int iter_head, |
241699cd AV |
1392 | size_t *start) |
1393 | { | |
1394 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1395 | unsigned int p_mask = pipe->ring_size - 1; |
1396 | ssize_t n = push_pipe(i, maxsize, &iter_head, start); | |
241699cd AV |
1397 | if (!n) |
1398 | return -EFAULT; | |
1399 | ||
1400 | maxsize = n; | |
1401 | n += *start; | |
1689c73a | 1402 | while (n > 0) { |
8cefc107 DH |
1403 | get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); |
1404 | iter_head++; | |
241699cd AV |
1405 | n -= PAGE_SIZE; |
1406 | } | |
1407 | ||
1408 | return maxsize; | |
1409 | } | |
1410 | ||
1411 | static ssize_t pipe_get_pages(struct iov_iter *i, | |
1412 | struct page **pages, size_t maxsize, unsigned maxpages, | |
1413 | size_t *start) | |
1414 | { | |
8cefc107 | 1415 | unsigned int iter_head, npages; |
241699cd | 1416 | size_t capacity; |
241699cd | 1417 | |
33844e66 AV |
1418 | if (!maxsize) |
1419 | return 0; | |
1420 | ||
241699cd AV |
1421 | if (!sanity(i)) |
1422 | return -EFAULT; | |
1423 | ||
8cefc107 DH |
1424 | data_start(i, &iter_head, start); |
1425 | /* Amount of free space: some of this one + all after this one */ | |
1426 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
1427 | capacity = min(npages, maxpages) * PAGE_SIZE - *start; | |
241699cd | 1428 | |
8cefc107 | 1429 | return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); |
241699cd AV |
1430 | } |
1431 | ||
7ff50620 DH |
1432 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
1433 | pgoff_t index, unsigned int nr_pages) | |
1434 | { | |
1435 | XA_STATE(xas, xa, index); | |
1436 | struct page *page; | |
1437 | unsigned int ret = 0; | |
1438 | ||
1439 | rcu_read_lock(); | |
1440 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1441 | if (xas_retry(&xas, page)) | |
1442 | continue; | |
1443 | ||
1444 | /* Has the page moved or been split? */ | |
1445 | if (unlikely(page != xas_reload(&xas))) { | |
1446 | xas_reset(&xas); | |
1447 | continue; | |
1448 | } | |
1449 | ||
1450 | pages[ret] = find_subpage(page, xas.xa_index); | |
1451 | get_page(pages[ret]); | |
1452 | if (++ret == nr_pages) | |
1453 | break; | |
1454 | } | |
1455 | rcu_read_unlock(); | |
1456 | return ret; | |
1457 | } | |
1458 | ||
1459 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, | |
1460 | struct page **pages, size_t maxsize, | |
1461 | unsigned maxpages, size_t *_start_offset) | |
1462 | { | |
1463 | unsigned nr, offset; | |
1464 | pgoff_t index, count; | |
1465 | size_t size = maxsize, actual; | |
1466 | loff_t pos; | |
1467 | ||
1468 | if (!size || !maxpages) | |
1469 | return 0; | |
1470 | ||
1471 | pos = i->xarray_start + i->iov_offset; | |
1472 | index = pos >> PAGE_SHIFT; | |
1473 | offset = pos & ~PAGE_MASK; | |
1474 | *_start_offset = offset; | |
1475 | ||
1476 | count = 1; | |
1477 | if (size > PAGE_SIZE - offset) { | |
1478 | size -= PAGE_SIZE - offset; | |
1479 | count += size >> PAGE_SHIFT; | |
1480 | size &= ~PAGE_MASK; | |
1481 | if (size) | |
1482 | count++; | |
1483 | } | |
1484 | ||
1485 | if (count > maxpages) | |
1486 | count = maxpages; | |
1487 | ||
1488 | nr = iter_xarray_populate_pages(pages, i->xarray, index, count); | |
1489 | if (nr == 0) | |
1490 | return 0; | |
1491 | ||
1492 | actual = PAGE_SIZE * nr; | |
1493 | actual -= offset; | |
1494 | if (nr == count && size > 0) { | |
1495 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1496 | actual -= PAGE_SIZE - (last_offset + size); | |
1497 | } | |
1498 | return actual; | |
1499 | } | |
1500 | ||
62a8067a | 1501 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
2c80929c | 1502 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
1503 | size_t *start) |
1504 | { | |
e5393fae AV |
1505 | if (maxsize > i->count) |
1506 | maxsize = i->count; | |
1507 | ||
00e23707 | 1508 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1509 | return pipe_get_pages(i, pages, maxsize, maxpages, start); |
7ff50620 DH |
1510 | if (unlikely(iov_iter_is_xarray(i))) |
1511 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); | |
9ea9ce04 DH |
1512 | if (unlikely(iov_iter_is_discard(i))) |
1513 | return -EFAULT; | |
1514 | ||
e5393fae AV |
1515 | iterate_all_kinds(i, maxsize, v, ({ |
1516 | unsigned long addr = (unsigned long)v.iov_base; | |
1517 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
1518 | int n; | |
1519 | int res; | |
1520 | ||
1521 | if (len > maxpages * PAGE_SIZE) | |
1522 | len = maxpages * PAGE_SIZE; | |
1523 | addr &= ~(PAGE_SIZE - 1); | |
1524 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
73b0140b IW |
1525 | res = get_user_pages_fast(addr, n, |
1526 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, | |
1527 | pages); | |
e5393fae AV |
1528 | if (unlikely(res < 0)) |
1529 | return res; | |
1530 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
1531 | 0;}),({ | |
1532 | /* can't be more than PAGE_SIZE */ | |
1533 | *start = v.bv_offset; | |
1534 | get_page(*pages = v.bv_page); | |
1535 | return v.bv_len; | |
a280455f AV |
1536 | }),({ |
1537 | return -EFAULT; | |
7ff50620 DH |
1538 | }), |
1539 | 0 | |
e5393fae AV |
1540 | ) |
1541 | return 0; | |
62a8067a AV |
1542 | } |
1543 | EXPORT_SYMBOL(iov_iter_get_pages); | |
1544 | ||
1b17f1f2 AV |
1545 | static struct page **get_pages_array(size_t n) |
1546 | { | |
752ade68 | 1547 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); |
1b17f1f2 AV |
1548 | } |
1549 | ||
241699cd AV |
1550 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
1551 | struct page ***pages, size_t maxsize, | |
1552 | size_t *start) | |
1553 | { | |
1554 | struct page **p; | |
8cefc107 | 1555 | unsigned int iter_head, npages; |
d7760d63 | 1556 | ssize_t n; |
241699cd | 1557 | |
33844e66 AV |
1558 | if (!maxsize) |
1559 | return 0; | |
1560 | ||
241699cd AV |
1561 | if (!sanity(i)) |
1562 | return -EFAULT; | |
1563 | ||
8cefc107 DH |
1564 | data_start(i, &iter_head, start); |
1565 | /* Amount of free space: some of this one + all after this one */ | |
1566 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
241699cd AV |
1567 | n = npages * PAGE_SIZE - *start; |
1568 | if (maxsize > n) | |
1569 | maxsize = n; | |
1570 | else | |
1571 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); | |
1572 | p = get_pages_array(npages); | |
1573 | if (!p) | |
1574 | return -ENOMEM; | |
8cefc107 | 1575 | n = __pipe_get_pages(i, maxsize, p, iter_head, start); |
241699cd AV |
1576 | if (n > 0) |
1577 | *pages = p; | |
1578 | else | |
1579 | kvfree(p); | |
1580 | return n; | |
1581 | } | |
1582 | ||
7ff50620 DH |
1583 | static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, |
1584 | struct page ***pages, size_t maxsize, | |
1585 | size_t *_start_offset) | |
1586 | { | |
1587 | struct page **p; | |
1588 | unsigned nr, offset; | |
1589 | pgoff_t index, count; | |
1590 | size_t size = maxsize, actual; | |
1591 | loff_t pos; | |
1592 | ||
1593 | if (!size) | |
1594 | return 0; | |
1595 | ||
1596 | pos = i->xarray_start + i->iov_offset; | |
1597 | index = pos >> PAGE_SHIFT; | |
1598 | offset = pos & ~PAGE_MASK; | |
1599 | *_start_offset = offset; | |
1600 | ||
1601 | count = 1; | |
1602 | if (size > PAGE_SIZE - offset) { | |
1603 | size -= PAGE_SIZE - offset; | |
1604 | count += size >> PAGE_SHIFT; | |
1605 | size &= ~PAGE_MASK; | |
1606 | if (size) | |
1607 | count++; | |
1608 | } | |
1609 | ||
1610 | p = get_pages_array(count); | |
1611 | if (!p) | |
1612 | return -ENOMEM; | |
1613 | *pages = p; | |
1614 | ||
1615 | nr = iter_xarray_populate_pages(p, i->xarray, index, count); | |
1616 | if (nr == 0) | |
1617 | return 0; | |
1618 | ||
1619 | actual = PAGE_SIZE * nr; | |
1620 | actual -= offset; | |
1621 | if (nr == count && size > 0) { | |
1622 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1623 | actual -= PAGE_SIZE - (last_offset + size); | |
1624 | } | |
1625 | return actual; | |
1626 | } | |
1627 | ||
62a8067a AV |
1628 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
1629 | struct page ***pages, size_t maxsize, | |
1630 | size_t *start) | |
1631 | { | |
1b17f1f2 AV |
1632 | struct page **p; |
1633 | ||
1634 | if (maxsize > i->count) | |
1635 | maxsize = i->count; | |
1636 | ||
00e23707 | 1637 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1638 | return pipe_get_pages_alloc(i, pages, maxsize, start); |
7ff50620 DH |
1639 | if (unlikely(iov_iter_is_xarray(i))) |
1640 | return iter_xarray_get_pages_alloc(i, pages, maxsize, start); | |
9ea9ce04 DH |
1641 | if (unlikely(iov_iter_is_discard(i))) |
1642 | return -EFAULT; | |
1643 | ||
1b17f1f2 AV |
1644 | iterate_all_kinds(i, maxsize, v, ({ |
1645 | unsigned long addr = (unsigned long)v.iov_base; | |
1646 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
1647 | int n; | |
1648 | int res; | |
1649 | ||
1650 | addr &= ~(PAGE_SIZE - 1); | |
1651 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1652 | p = get_pages_array(n); | |
1653 | if (!p) | |
1654 | return -ENOMEM; | |
73b0140b IW |
1655 | res = get_user_pages_fast(addr, n, |
1656 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); | |
1b17f1f2 AV |
1657 | if (unlikely(res < 0)) { |
1658 | kvfree(p); | |
1659 | return res; | |
1660 | } | |
1661 | *pages = p; | |
1662 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
1663 | 0;}),({ | |
1664 | /* can't be more than PAGE_SIZE */ | |
1665 | *start = v.bv_offset; | |
1666 | *pages = p = get_pages_array(1); | |
1667 | if (!p) | |
1668 | return -ENOMEM; | |
1669 | get_page(*p = v.bv_page); | |
1670 | return v.bv_len; | |
a280455f AV |
1671 | }),({ |
1672 | return -EFAULT; | |
7ff50620 | 1673 | }), 0 |
1b17f1f2 AV |
1674 | ) |
1675 | return 0; | |
62a8067a AV |
1676 | } |
1677 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
1678 | ||
a604ec7e AV |
1679 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1680 | struct iov_iter *i) | |
1681 | { | |
1682 | char *to = addr; | |
1683 | __wsum sum, next; | |
1684 | size_t off = 0; | |
a604ec7e | 1685 | sum = *csum; |
9ea9ce04 | 1686 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1687 | WARN_ON(1); |
1688 | return 0; | |
1689 | } | |
a604ec7e | 1690 | iterate_and_advance(i, bytes, v, ({ |
cbbd26b8 | 1691 | next = csum_and_copy_from_user(v.iov_base, |
a604ec7e | 1692 | (to += v.iov_len) - v.iov_len, |
c693cc46 AV |
1693 | v.iov_len); |
1694 | if (next) { | |
a604ec7e AV |
1695 | sum = csum_block_add(sum, next, off); |
1696 | off += v.iov_len; | |
1697 | } | |
c693cc46 | 1698 | next ? 0 : v.iov_len; |
a604ec7e AV |
1699 | }), ({ |
1700 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1701 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
1702 | p + v.bv_offset, v.bv_len, | |
1703 | sum, off); | |
a604ec7e | 1704 | kunmap_atomic(p); |
a604ec7e AV |
1705 | off += v.bv_len; |
1706 | }),({ | |
f9152895 AV |
1707 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
1708 | v.iov_base, v.iov_len, | |
1709 | sum, off); | |
a604ec7e | 1710 | off += v.iov_len; |
7ff50620 DH |
1711 | }), ({ |
1712 | char *p = kmap_atomic(v.bv_page); | |
1713 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, | |
1714 | p + v.bv_offset, v.bv_len, | |
1715 | sum, off); | |
1716 | kunmap_atomic(p); | |
1717 | off += v.bv_len; | |
a604ec7e AV |
1718 | }) |
1719 | ) | |
1720 | *csum = sum; | |
1721 | return bytes; | |
1722 | } | |
1723 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1724 | ||
cbbd26b8 AV |
1725 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, |
1726 | struct iov_iter *i) | |
1727 | { | |
1728 | char *to = addr; | |
1729 | __wsum sum, next; | |
1730 | size_t off = 0; | |
1731 | sum = *csum; | |
9ea9ce04 | 1732 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
cbbd26b8 AV |
1733 | WARN_ON(1); |
1734 | return false; | |
1735 | } | |
1736 | if (unlikely(i->count < bytes)) | |
1737 | return false; | |
1738 | iterate_all_kinds(i, bytes, v, ({ | |
cbbd26b8 AV |
1739 | next = csum_and_copy_from_user(v.iov_base, |
1740 | (to += v.iov_len) - v.iov_len, | |
c693cc46 AV |
1741 | v.iov_len); |
1742 | if (!next) | |
cbbd26b8 AV |
1743 | return false; |
1744 | sum = csum_block_add(sum, next, off); | |
1745 | off += v.iov_len; | |
1746 | 0; | |
1747 | }), ({ | |
1748 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1749 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
1750 | p + v.bv_offset, v.bv_len, | |
1751 | sum, off); | |
cbbd26b8 | 1752 | kunmap_atomic(p); |
cbbd26b8 AV |
1753 | off += v.bv_len; |
1754 | }),({ | |
f9152895 AV |
1755 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
1756 | v.iov_base, v.iov_len, | |
1757 | sum, off); | |
cbbd26b8 | 1758 | off += v.iov_len; |
7ff50620 DH |
1759 | }), ({ |
1760 | char *p = kmap_atomic(v.bv_page); | |
1761 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, | |
1762 | p + v.bv_offset, v.bv_len, | |
1763 | sum, off); | |
1764 | kunmap_atomic(p); | |
1765 | off += v.bv_len; | |
cbbd26b8 AV |
1766 | }) |
1767 | ) | |
1768 | *csum = sum; | |
1769 | iov_iter_advance(i, bytes); | |
1770 | return true; | |
1771 | } | |
1772 | EXPORT_SYMBOL(csum_and_copy_from_iter_full); | |
1773 | ||
52cbd23a | 1774 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
a604ec7e AV |
1775 | struct iov_iter *i) |
1776 | { | |
52cbd23a | 1777 | struct csum_state *csstate = _csstate; |
36f7a8a4 | 1778 | const char *from = addr; |
a604ec7e | 1779 | __wsum sum, next; |
52cbd23a | 1780 | size_t off; |
78e1f386 AV |
1781 | |
1782 | if (unlikely(iov_iter_is_pipe(i))) | |
52cbd23a | 1783 | return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); |
78e1f386 | 1784 | |
52cbd23a WB |
1785 | sum = csstate->csum; |
1786 | off = csstate->off; | |
78e1f386 | 1787 | if (unlikely(iov_iter_is_discard(i))) { |
241699cd AV |
1788 | WARN_ON(1); /* for now */ |
1789 | return 0; | |
1790 | } | |
a604ec7e | 1791 | iterate_and_advance(i, bytes, v, ({ |
a604ec7e | 1792 | next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, |
cbbd26b8 | 1793 | v.iov_base, |
c693cc46 AV |
1794 | v.iov_len); |
1795 | if (next) { | |
a604ec7e AV |
1796 | sum = csum_block_add(sum, next, off); |
1797 | off += v.iov_len; | |
1798 | } | |
c693cc46 | 1799 | next ? 0 : v.iov_len; |
a604ec7e AV |
1800 | }), ({ |
1801 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1802 | sum = csum_and_memcpy(p + v.bv_offset, |
1803 | (from += v.bv_len) - v.bv_len, | |
1804 | v.bv_len, sum, off); | |
a604ec7e | 1805 | kunmap_atomic(p); |
a604ec7e AV |
1806 | off += v.bv_len; |
1807 | }),({ | |
f9152895 AV |
1808 | sum = csum_and_memcpy(v.iov_base, |
1809 | (from += v.iov_len) - v.iov_len, | |
1810 | v.iov_len, sum, off); | |
a604ec7e | 1811 | off += v.iov_len; |
7ff50620 DH |
1812 | }), ({ |
1813 | char *p = kmap_atomic(v.bv_page); | |
1814 | sum = csum_and_memcpy(p + v.bv_offset, | |
1815 | (from += v.bv_len) - v.bv_len, | |
1816 | v.bv_len, sum, off); | |
1817 | kunmap_atomic(p); | |
1818 | off += v.bv_len; | |
a604ec7e AV |
1819 | }) |
1820 | ) | |
52cbd23a WB |
1821 | csstate->csum = sum; |
1822 | csstate->off = off; | |
a604ec7e AV |
1823 | return bytes; |
1824 | } | |
1825 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1826 | ||
d05f4435 SG |
1827 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
1828 | struct iov_iter *i) | |
1829 | { | |
7999096f | 1830 | #ifdef CONFIG_CRYPTO_HASH |
d05f4435 SG |
1831 | struct ahash_request *hash = hashp; |
1832 | struct scatterlist sg; | |
1833 | size_t copied; | |
1834 | ||
1835 | copied = copy_to_iter(addr, bytes, i); | |
1836 | sg_init_one(&sg, addr, copied); | |
1837 | ahash_request_set_crypt(hash, &sg, NULL, copied); | |
1838 | crypto_ahash_update(hash); | |
1839 | return copied; | |
27fad74a Y |
1840 | #else |
1841 | return 0; | |
1842 | #endif | |
d05f4435 SG |
1843 | } |
1844 | EXPORT_SYMBOL(hash_and_copy_to_iter); | |
1845 | ||
62a8067a AV |
1846 | int iov_iter_npages(const struct iov_iter *i, int maxpages) |
1847 | { | |
e0f2dc40 AV |
1848 | size_t size = i->count; |
1849 | int npages = 0; | |
1850 | ||
1851 | if (!size) | |
1852 | return 0; | |
9ea9ce04 DH |
1853 | if (unlikely(iov_iter_is_discard(i))) |
1854 | return 0; | |
e0f2dc40 | 1855 | |
00e23707 | 1856 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd | 1857 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 | 1858 | unsigned int iter_head; |
241699cd | 1859 | size_t off; |
241699cd AV |
1860 | |
1861 | if (!sanity(i)) | |
1862 | return 0; | |
1863 | ||
8cefc107 | 1864 | data_start(i, &iter_head, &off); |
241699cd | 1865 | /* some of this one + all after this one */ |
8cefc107 | 1866 | npages = pipe_space_for_user(iter_head, pipe->tail, pipe); |
241699cd AV |
1867 | if (npages >= maxpages) |
1868 | return maxpages; | |
7ff50620 DH |
1869 | } else if (unlikely(iov_iter_is_xarray(i))) { |
1870 | unsigned offset; | |
1871 | ||
1872 | offset = (i->xarray_start + i->iov_offset) & ~PAGE_MASK; | |
1873 | ||
1874 | npages = 1; | |
1875 | if (size > PAGE_SIZE - offset) { | |
1876 | size -= PAGE_SIZE - offset; | |
1877 | npages += size >> PAGE_SHIFT; | |
1878 | size &= ~PAGE_MASK; | |
1879 | if (size) | |
1880 | npages++; | |
1881 | } | |
1882 | if (npages >= maxpages) | |
1883 | return maxpages; | |
241699cd | 1884 | } else iterate_all_kinds(i, size, v, ({ |
e0f2dc40 AV |
1885 | unsigned long p = (unsigned long)v.iov_base; |
1886 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
1887 | - p / PAGE_SIZE; | |
1888 | if (npages >= maxpages) | |
1889 | return maxpages; | |
1890 | 0;}),({ | |
1891 | npages++; | |
1892 | if (npages >= maxpages) | |
1893 | return maxpages; | |
a280455f AV |
1894 | }),({ |
1895 | unsigned long p = (unsigned long)v.iov_base; | |
1896 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
1897 | - p / PAGE_SIZE; | |
1898 | if (npages >= maxpages) | |
1899 | return maxpages; | |
7ff50620 DH |
1900 | }), |
1901 | 0 | |
e0f2dc40 AV |
1902 | ) |
1903 | return npages; | |
62a8067a | 1904 | } |
f67da30c | 1905 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1906 | |
1907 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1908 | { | |
1909 | *new = *old; | |
00e23707 | 1910 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1911 | WARN_ON(1); |
1912 | return NULL; | |
1913 | } | |
7ff50620 | 1914 | if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) |
9ea9ce04 | 1915 | return NULL; |
00e23707 | 1916 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1917 | return new->bvec = kmemdup(new->bvec, |
1918 | new->nr_segs * sizeof(struct bio_vec), | |
1919 | flags); | |
1920 | else | |
1921 | /* iovec and kvec have identical layout */ | |
1922 | return new->iov = kmemdup(new->iov, | |
1923 | new->nr_segs * sizeof(struct iovec), | |
1924 | flags); | |
1925 | } | |
1926 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1927 | |
bfdc5970 CH |
1928 | static int copy_compat_iovec_from_user(struct iovec *iov, |
1929 | const struct iovec __user *uvec, unsigned long nr_segs) | |
1930 | { | |
1931 | const struct compat_iovec __user *uiov = | |
1932 | (const struct compat_iovec __user *)uvec; | |
1933 | int ret = -EFAULT, i; | |
1934 | ||
a959a978 | 1935 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
1936 | return -EFAULT; |
1937 | ||
1938 | for (i = 0; i < nr_segs; i++) { | |
1939 | compat_uptr_t buf; | |
1940 | compat_ssize_t len; | |
1941 | ||
1942 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); | |
1943 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); | |
1944 | ||
1945 | /* check for compat_size_t not fitting in compat_ssize_t .. */ | |
1946 | if (len < 0) { | |
1947 | ret = -EINVAL; | |
1948 | goto uaccess_end; | |
1949 | } | |
1950 | iov[i].iov_base = compat_ptr(buf); | |
1951 | iov[i].iov_len = len; | |
1952 | } | |
1953 | ||
1954 | ret = 0; | |
1955 | uaccess_end: | |
1956 | user_access_end(); | |
1957 | return ret; | |
1958 | } | |
1959 | ||
1960 | static int copy_iovec_from_user(struct iovec *iov, | |
1961 | const struct iovec __user *uvec, unsigned long nr_segs) | |
fb041b59 DL |
1962 | { |
1963 | unsigned long seg; | |
fb041b59 | 1964 | |
bfdc5970 CH |
1965 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
1966 | return -EFAULT; | |
1967 | for (seg = 0; seg < nr_segs; seg++) { | |
1968 | if ((ssize_t)iov[seg].iov_len < 0) | |
1969 | return -EINVAL; | |
fb041b59 DL |
1970 | } |
1971 | ||
bfdc5970 CH |
1972 | return 0; |
1973 | } | |
1974 | ||
1975 | struct iovec *iovec_from_user(const struct iovec __user *uvec, | |
1976 | unsigned long nr_segs, unsigned long fast_segs, | |
1977 | struct iovec *fast_iov, bool compat) | |
1978 | { | |
1979 | struct iovec *iov = fast_iov; | |
1980 | int ret; | |
1981 | ||
fb041b59 | 1982 | /* |
bfdc5970 CH |
1983 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
1984 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
1985 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 1986 | */ |
bfdc5970 CH |
1987 | if (nr_segs == 0) |
1988 | return iov; | |
1989 | if (nr_segs > UIO_MAXIOV) | |
1990 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
1991 | if (nr_segs > fast_segs) { |
1992 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
1993 | if (!iov) |
1994 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 1995 | } |
bfdc5970 CH |
1996 | |
1997 | if (compat) | |
1998 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); | |
1999 | else | |
2000 | ret = copy_iovec_from_user(iov, uvec, nr_segs); | |
2001 | if (ret) { | |
2002 | if (iov != fast_iov) | |
2003 | kfree(iov); | |
2004 | return ERR_PTR(ret); | |
2005 | } | |
2006 | ||
2007 | return iov; | |
2008 | } | |
2009 | ||
2010 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
2011 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
2012 | struct iov_iter *i, bool compat) | |
2013 | { | |
2014 | ssize_t total_len = 0; | |
2015 | unsigned long seg; | |
2016 | struct iovec *iov; | |
2017 | ||
2018 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); | |
2019 | if (IS_ERR(iov)) { | |
2020 | *iovp = NULL; | |
2021 | return PTR_ERR(iov); | |
fb041b59 DL |
2022 | } |
2023 | ||
2024 | /* | |
bfdc5970 CH |
2025 | * According to the Single Unix Specification we should return EINVAL if |
2026 | * an element length is < 0 when cast to ssize_t or if the total length | |
2027 | * would overflow the ssize_t return value of the system call. | |
fb041b59 DL |
2028 | * |
2029 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
2030 | * overflow case. | |
2031 | */ | |
fb041b59 | 2032 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
2033 | ssize_t len = (ssize_t)iov[seg].iov_len; |
2034 | ||
bfdc5970 CH |
2035 | if (!access_ok(iov[seg].iov_base, len)) { |
2036 | if (iov != *iovp) | |
2037 | kfree(iov); | |
2038 | *iovp = NULL; | |
2039 | return -EFAULT; | |
fb041b59 | 2040 | } |
bfdc5970 CH |
2041 | |
2042 | if (len > MAX_RW_COUNT - total_len) { | |
2043 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
2044 | iov[seg].iov_len = len; |
2045 | } | |
bfdc5970 | 2046 | total_len += len; |
fb041b59 | 2047 | } |
bfdc5970 CH |
2048 | |
2049 | iov_iter_init(i, type, iov, nr_segs, total_len); | |
2050 | if (iov == *iovp) | |
2051 | *iovp = NULL; | |
2052 | else | |
2053 | *iovp = iov; | |
2054 | return total_len; | |
fb041b59 DL |
2055 | } |
2056 | ||
ffecee4f VN |
2057 | /** |
2058 | * import_iovec() - Copy an array of &struct iovec from userspace | |
2059 | * into the kernel, check that it is valid, and initialize a new | |
2060 | * &struct iov_iter iterator to access it. | |
2061 | * | |
2062 | * @type: One of %READ or %WRITE. | |
bfdc5970 | 2063 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
2064 | * @nr_segs: Number of elements in userspace array. |
2065 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 2066 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
2067 | * on-stack) kernel array. |
2068 | * @i: Pointer to iterator that will be initialized on success. | |
2069 | * | |
2070 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
2071 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
2072 | * array will be allocated and the result placed in *@iov. This means that | |
2073 | * the caller may call kfree() on *@iov regardless of whether the small | |
2074 | * on-stack array was used or not (and regardless of whether this function | |
2075 | * returns an error or not). | |
2076 | * | |
87e5e6da | 2077 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 2078 | */ |
bfdc5970 | 2079 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 2080 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 2081 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 2082 | { |
89cd35c5 CH |
2083 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
2084 | in_compat_syscall()); | |
bc917be8 AV |
2085 | } |
2086 | EXPORT_SYMBOL(import_iovec); | |
2087 | ||
bc917be8 AV |
2088 | int import_single_range(int rw, void __user *buf, size_t len, |
2089 | struct iovec *iov, struct iov_iter *i) | |
2090 | { | |
2091 | if (len > MAX_RW_COUNT) | |
2092 | len = MAX_RW_COUNT; | |
96d4f267 | 2093 | if (unlikely(!access_ok(buf, len))) |
bc917be8 AV |
2094 | return -EFAULT; |
2095 | ||
2096 | iov->iov_base = buf; | |
2097 | iov->iov_len = len; | |
2098 | iov_iter_init(i, rw, iov, 1, len); | |
2099 | return 0; | |
2100 | } | |
e1267585 | 2101 | EXPORT_SYMBOL(import_single_range); |
09cf698a AV |
2102 | |
2103 | int iov_iter_for_each_range(struct iov_iter *i, size_t bytes, | |
2104 | int (*f)(struct kvec *vec, void *context), | |
2105 | void *context) | |
2106 | { | |
2107 | struct kvec w; | |
2108 | int err = -EINVAL; | |
2109 | if (!bytes) | |
2110 | return 0; | |
2111 | ||
2112 | iterate_all_kinds(i, bytes, v, -EINVAL, ({ | |
2113 | w.iov_base = kmap(v.bv_page) + v.bv_offset; | |
2114 | w.iov_len = v.bv_len; | |
2115 | err = f(&w, context); | |
2116 | kunmap(v.bv_page); | |
2117 | err;}), ({ | |
2118 | w = v; | |
7ff50620 DH |
2119 | err = f(&w, context);}), ({ |
2120 | w.iov_base = kmap(v.bv_page) + v.bv_offset; | |
2121 | w.iov_len = v.bv_len; | |
2122 | err = f(&w, context); | |
2123 | kunmap(v.bv_page); | |
2124 | err;}) | |
09cf698a AV |
2125 | ) |
2126 | return err; | |
2127 | } | |
2128 | EXPORT_SYMBOL(iov_iter_for_each_range); |