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(); | |
794 | return bytes; | |
795 | } | |
8780356e DW |
796 | }) |
797 | ) | |
798 | ||
799 | return bytes; | |
800 | } | |
ec6347bb DW |
801 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
802 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 803 | |
aa28de27 | 804 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 805 | { |
0dbca9a4 | 806 | char *to = addr; |
00e23707 | 807 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
808 | WARN_ON(1); |
809 | return 0; | |
810 | } | |
09fc68dc AV |
811 | if (iter_is_iovec(i)) |
812 | might_fault(); | |
0dbca9a4 | 813 | iterate_and_advance(i, bytes, v, |
09fc68dc | 814 | copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
0dbca9a4 | 815 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 816 | v.bv_offset, v.bv_len), |
7ff50620 DH |
817 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
818 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
819 | v.bv_offset, v.bv_len) | |
0dbca9a4 AV |
820 | ) |
821 | ||
822 | return bytes; | |
c35e0248 | 823 | } |
aa28de27 | 824 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 825 | |
aa28de27 | 826 | bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) |
cbbd26b8 AV |
827 | { |
828 | char *to = addr; | |
00e23707 | 829 | if (unlikely(iov_iter_is_pipe(i))) { |
cbbd26b8 AV |
830 | WARN_ON(1); |
831 | return false; | |
832 | } | |
33844e66 | 833 | if (unlikely(i->count < bytes)) |
cbbd26b8 AV |
834 | return false; |
835 | ||
09fc68dc AV |
836 | if (iter_is_iovec(i)) |
837 | might_fault(); | |
cbbd26b8 | 838 | iterate_all_kinds(i, bytes, v, ({ |
09fc68dc | 839 | if (copyin((to += v.iov_len) - v.iov_len, |
cbbd26b8 AV |
840 | v.iov_base, v.iov_len)) |
841 | return false; | |
842 | 0;}), | |
843 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
844 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
845 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
846 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
847 | v.bv_offset, v.bv_len) | |
cbbd26b8 AV |
848 | ) |
849 | ||
850 | iov_iter_advance(i, bytes); | |
851 | return true; | |
852 | } | |
aa28de27 | 853 | EXPORT_SYMBOL(_copy_from_iter_full); |
cbbd26b8 | 854 | |
aa28de27 | 855 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 AV |
856 | { |
857 | char *to = addr; | |
00e23707 | 858 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
859 | WARN_ON(1); |
860 | return 0; | |
861 | } | |
aa583096 | 862 | iterate_and_advance(i, bytes, v, |
3f763453 | 863 | __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
aa583096 AV |
864 | v.iov_base, v.iov_len), |
865 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
866 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
867 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
868 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
869 | v.bv_offset, v.bv_len) | |
aa583096 AV |
870 | ) |
871 | ||
872 | return bytes; | |
873 | } | |
aa28de27 | 874 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 875 | |
0aed55af | 876 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
877 | /** |
878 | * _copy_from_iter_flushcache - write destination through cpu cache | |
879 | * @addr: destination kernel address | |
880 | * @bytes: total transfer length | |
881 | * @iter: source iterator | |
882 | * | |
883 | * The pmem driver arranges for filesystem-dax to use this facility via | |
884 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
885 | * are flushed through the CPU cache. It is differentiated from | |
886 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
887 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
888 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
889 | * instructions that strand dirty-data in the cache. | |
890 | */ | |
6a37e940 | 891 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af DW |
892 | { |
893 | char *to = addr; | |
00e23707 | 894 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
895 | WARN_ON(1); |
896 | return 0; | |
897 | } | |
898 | iterate_and_advance(i, bytes, v, | |
899 | __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, | |
900 | v.iov_base, v.iov_len), | |
901 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
902 | v.bv_offset, v.bv_len), | |
903 | memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, | |
7ff50620 DH |
904 | v.iov_len), |
905 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
906 | v.bv_offset, v.bv_len) | |
0aed55af DW |
907 | ) |
908 | ||
909 | return bytes; | |
910 | } | |
6a37e940 | 911 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
912 | #endif |
913 | ||
aa28de27 | 914 | bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) |
cbbd26b8 AV |
915 | { |
916 | char *to = addr; | |
00e23707 | 917 | if (unlikely(iov_iter_is_pipe(i))) { |
cbbd26b8 AV |
918 | WARN_ON(1); |
919 | return false; | |
920 | } | |
33844e66 | 921 | if (unlikely(i->count < bytes)) |
cbbd26b8 AV |
922 | return false; |
923 | iterate_all_kinds(i, bytes, v, ({ | |
3f763453 | 924 | if (__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
cbbd26b8 AV |
925 | v.iov_base, v.iov_len)) |
926 | return false; | |
927 | 0;}), | |
928 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
929 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
930 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
931 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
932 | v.bv_offset, v.bv_len) | |
cbbd26b8 AV |
933 | ) |
934 | ||
935 | iov_iter_advance(i, bytes); | |
936 | return true; | |
937 | } | |
aa28de27 | 938 | EXPORT_SYMBOL(_copy_from_iter_full_nocache); |
cbbd26b8 | 939 | |
72e809ed AV |
940 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
941 | { | |
6daef95b ED |
942 | struct page *head; |
943 | size_t v = n + offset; | |
944 | ||
945 | /* | |
946 | * The general case needs to access the page order in order | |
947 | * to compute the page size. | |
948 | * However, we mostly deal with order-0 pages and thus can | |
949 | * avoid a possible cache line miss for requests that fit all | |
950 | * page orders. | |
951 | */ | |
952 | if (n <= v && v <= PAGE_SIZE) | |
953 | return true; | |
954 | ||
955 | head = compound_head(page); | |
956 | v += (page - head) << PAGE_SHIFT; | |
a90bcb86 | 957 | |
a50b854e | 958 | if (likely(n <= v && v <= (page_size(head)))) |
72e809ed AV |
959 | return true; |
960 | WARN_ON(1); | |
961 | return false; | |
962 | } | |
cbbd26b8 | 963 | |
62a8067a AV |
964 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
965 | struct iov_iter *i) | |
966 | { | |
72e809ed AV |
967 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
968 | return 0; | |
7ff50620 | 969 | if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { |
d271524a AV |
970 | void *kaddr = kmap_atomic(page); |
971 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); | |
972 | kunmap_atomic(kaddr); | |
973 | return wanted; | |
9ea9ce04 DH |
974 | } else if (unlikely(iov_iter_is_discard(i))) |
975 | return bytes; | |
976 | else if (likely(!iov_iter_is_pipe(i))) | |
62a8067a | 977 | return copy_page_to_iter_iovec(page, offset, bytes, i); |
241699cd AV |
978 | else |
979 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
62a8067a AV |
980 | } |
981 | EXPORT_SYMBOL(copy_page_to_iter); | |
982 | ||
983 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
984 | struct iov_iter *i) | |
985 | { | |
72e809ed AV |
986 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
987 | return 0; | |
9ea9ce04 | 988 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
989 | WARN_ON(1); |
990 | return 0; | |
991 | } | |
7ff50620 | 992 | if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { |
d271524a | 993 | void *kaddr = kmap_atomic(page); |
aa28de27 | 994 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
d271524a AV |
995 | kunmap_atomic(kaddr); |
996 | return wanted; | |
997 | } else | |
62a8067a AV |
998 | return copy_page_from_iter_iovec(page, offset, bytes, i); |
999 | } | |
1000 | EXPORT_SYMBOL(copy_page_from_iter); | |
1001 | ||
241699cd AV |
1002 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
1003 | { | |
1004 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1005 | unsigned int p_mask = pipe->ring_size - 1; |
1006 | unsigned int i_head; | |
241699cd | 1007 | size_t n, off; |
241699cd AV |
1008 | |
1009 | if (!sanity(i)) | |
1010 | return 0; | |
1011 | ||
8cefc107 | 1012 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
1013 | if (unlikely(!n)) |
1014 | return 0; | |
1015 | ||
8cefc107 | 1016 | do { |
241699cd | 1017 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
1018 | memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); |
1019 | i->head = i_head; | |
241699cd AV |
1020 | i->iov_offset = off + chunk; |
1021 | n -= chunk; | |
8cefc107 DH |
1022 | off = 0; |
1023 | i_head++; | |
1024 | } while (n); | |
241699cd AV |
1025 | i->count -= bytes; |
1026 | return bytes; | |
1027 | } | |
1028 | ||
c35e0248 MW |
1029 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
1030 | { | |
00e23707 | 1031 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1032 | return pipe_zero(bytes, i); |
8442fa46 | 1033 | iterate_and_advance(i, bytes, v, |
09fc68dc | 1034 | clear_user(v.iov_base, v.iov_len), |
a280455f | 1035 | memzero_page(v.bv_page, v.bv_offset, v.bv_len), |
7ff50620 DH |
1036 | memset(v.iov_base, 0, v.iov_len), |
1037 | memzero_page(v.bv_page, v.bv_offset, v.bv_len) | |
8442fa46 AV |
1038 | ) |
1039 | ||
1040 | return bytes; | |
c35e0248 MW |
1041 | } |
1042 | EXPORT_SYMBOL(iov_iter_zero); | |
1043 | ||
62a8067a AV |
1044 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
1045 | struct iov_iter *i, unsigned long offset, size_t bytes) | |
1046 | { | |
04a31165 | 1047 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
1048 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
1049 | kunmap_atomic(kaddr); | |
1050 | return 0; | |
1051 | } | |
9ea9ce04 | 1052 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1053 | kunmap_atomic(kaddr); |
1054 | WARN_ON(1); | |
1055 | return 0; | |
1056 | } | |
04a31165 | 1057 | iterate_all_kinds(i, bytes, v, |
09fc68dc | 1058 | copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
04a31165 | 1059 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 1060 | v.bv_offset, v.bv_len), |
7ff50620 DH |
1061 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
1062 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, | |
1063 | v.bv_offset, v.bv_len) | |
04a31165 AV |
1064 | ) |
1065 | kunmap_atomic(kaddr); | |
1066 | return bytes; | |
62a8067a AV |
1067 | } |
1068 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); | |
1069 | ||
b9dc6f65 AV |
1070 | static inline void pipe_truncate(struct iov_iter *i) |
1071 | { | |
1072 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1073 | unsigned int p_tail = pipe->tail; |
1074 | unsigned int p_head = pipe->head; | |
1075 | unsigned int p_mask = pipe->ring_size - 1; | |
1076 | ||
1077 | if (!pipe_empty(p_head, p_tail)) { | |
1078 | struct pipe_buffer *buf; | |
1079 | unsigned int i_head = i->head; | |
b9dc6f65 | 1080 | size_t off = i->iov_offset; |
8cefc107 | 1081 | |
b9dc6f65 | 1082 | if (off) { |
8cefc107 DH |
1083 | buf = &pipe->bufs[i_head & p_mask]; |
1084 | buf->len = off - buf->offset; | |
1085 | i_head++; | |
b9dc6f65 | 1086 | } |
8cefc107 DH |
1087 | while (p_head != i_head) { |
1088 | p_head--; | |
1089 | pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); | |
b9dc6f65 | 1090 | } |
8cefc107 DH |
1091 | |
1092 | pipe->head = p_head; | |
b9dc6f65 AV |
1093 | } |
1094 | } | |
1095 | ||
241699cd AV |
1096 | static void pipe_advance(struct iov_iter *i, size_t size) |
1097 | { | |
1098 | struct pipe_inode_info *pipe = i->pipe; | |
241699cd AV |
1099 | if (unlikely(i->count < size)) |
1100 | size = i->count; | |
241699cd | 1101 | if (size) { |
b9dc6f65 | 1102 | struct pipe_buffer *buf; |
8cefc107 DH |
1103 | unsigned int p_mask = pipe->ring_size - 1; |
1104 | unsigned int i_head = i->head; | |
b9dc6f65 | 1105 | size_t off = i->iov_offset, left = size; |
8cefc107 | 1106 | |
241699cd | 1107 | if (off) /* make it relative to the beginning of buffer */ |
8cefc107 | 1108 | left += off - pipe->bufs[i_head & p_mask].offset; |
241699cd | 1109 | while (1) { |
8cefc107 | 1110 | buf = &pipe->bufs[i_head & p_mask]; |
b9dc6f65 | 1111 | if (left <= buf->len) |
241699cd | 1112 | break; |
b9dc6f65 | 1113 | left -= buf->len; |
8cefc107 | 1114 | i_head++; |
241699cd | 1115 | } |
8cefc107 | 1116 | i->head = i_head; |
b9dc6f65 | 1117 | i->iov_offset = buf->offset + left; |
241699cd | 1118 | } |
b9dc6f65 AV |
1119 | i->count -= size; |
1120 | /* ... and discard everything past that point */ | |
1121 | pipe_truncate(i); | |
241699cd AV |
1122 | } |
1123 | ||
54c8195b PB |
1124 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
1125 | { | |
1126 | struct bvec_iter bi; | |
1127 | ||
1128 | bi.bi_size = i->count; | |
1129 | bi.bi_bvec_done = i->iov_offset; | |
1130 | bi.bi_idx = 0; | |
1131 | bvec_iter_advance(i->bvec, &bi, size); | |
1132 | ||
1133 | i->bvec += bi.bi_idx; | |
1134 | i->nr_segs -= bi.bi_idx; | |
1135 | i->count = bi.bi_size; | |
1136 | i->iov_offset = bi.bi_bvec_done; | |
1137 | } | |
1138 | ||
62a8067a AV |
1139 | void iov_iter_advance(struct iov_iter *i, size_t size) |
1140 | { | |
00e23707 | 1141 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
1142 | pipe_advance(i, size); |
1143 | return; | |
1144 | } | |
9ea9ce04 DH |
1145 | if (unlikely(iov_iter_is_discard(i))) { |
1146 | i->count -= size; | |
1147 | return; | |
1148 | } | |
7ff50620 DH |
1149 | if (unlikely(iov_iter_is_xarray(i))) { |
1150 | i->iov_offset += size; | |
1151 | i->count -= size; | |
1152 | return; | |
1153 | } | |
54c8195b PB |
1154 | if (iov_iter_is_bvec(i)) { |
1155 | iov_iter_bvec_advance(i, size); | |
1156 | return; | |
1157 | } | |
7ff50620 | 1158 | iterate_and_advance(i, size, v, 0, 0, 0, 0) |
62a8067a AV |
1159 | } |
1160 | EXPORT_SYMBOL(iov_iter_advance); | |
1161 | ||
27c0e374 AV |
1162 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
1163 | { | |
1164 | if (!unroll) | |
1165 | return; | |
5b47d59a AV |
1166 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
1167 | return; | |
27c0e374 | 1168 | i->count += unroll; |
00e23707 | 1169 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 | 1170 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 DH |
1171 | unsigned int p_mask = pipe->ring_size - 1; |
1172 | unsigned int i_head = i->head; | |
27c0e374 AV |
1173 | size_t off = i->iov_offset; |
1174 | while (1) { | |
8cefc107 DH |
1175 | struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; |
1176 | size_t n = off - b->offset; | |
27c0e374 | 1177 | if (unroll < n) { |
4fa55cef | 1178 | off -= unroll; |
27c0e374 AV |
1179 | break; |
1180 | } | |
1181 | unroll -= n; | |
8cefc107 | 1182 | if (!unroll && i_head == i->start_head) { |
27c0e374 AV |
1183 | off = 0; |
1184 | break; | |
1185 | } | |
8cefc107 DH |
1186 | i_head--; |
1187 | b = &pipe->bufs[i_head & p_mask]; | |
1188 | off = b->offset + b->len; | |
27c0e374 AV |
1189 | } |
1190 | i->iov_offset = off; | |
8cefc107 | 1191 | i->head = i_head; |
27c0e374 AV |
1192 | pipe_truncate(i); |
1193 | return; | |
1194 | } | |
9ea9ce04 DH |
1195 | if (unlikely(iov_iter_is_discard(i))) |
1196 | return; | |
27c0e374 AV |
1197 | if (unroll <= i->iov_offset) { |
1198 | i->iov_offset -= unroll; | |
1199 | return; | |
1200 | } | |
1201 | unroll -= i->iov_offset; | |
7ff50620 DH |
1202 | if (iov_iter_is_xarray(i)) { |
1203 | BUG(); /* We should never go beyond the start of the specified | |
1204 | * range since we might then be straying into pages that | |
1205 | * aren't pinned. | |
1206 | */ | |
1207 | } else if (iov_iter_is_bvec(i)) { | |
27c0e374 AV |
1208 | const struct bio_vec *bvec = i->bvec; |
1209 | while (1) { | |
1210 | size_t n = (--bvec)->bv_len; | |
1211 | i->nr_segs++; | |
1212 | if (unroll <= n) { | |
1213 | i->bvec = bvec; | |
1214 | i->iov_offset = n - unroll; | |
1215 | return; | |
1216 | } | |
1217 | unroll -= n; | |
1218 | } | |
1219 | } else { /* same logics for iovec and kvec */ | |
1220 | const struct iovec *iov = i->iov; | |
1221 | while (1) { | |
1222 | size_t n = (--iov)->iov_len; | |
1223 | i->nr_segs++; | |
1224 | if (unroll <= n) { | |
1225 | i->iov = iov; | |
1226 | i->iov_offset = n - unroll; | |
1227 | return; | |
1228 | } | |
1229 | unroll -= n; | |
1230 | } | |
1231 | } | |
1232 | } | |
1233 | EXPORT_SYMBOL(iov_iter_revert); | |
1234 | ||
62a8067a AV |
1235 | /* |
1236 | * Return the count of just the current iov_iter segment. | |
1237 | */ | |
1238 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
1239 | { | |
00e23707 | 1240 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1241 | return i->count; // it is a silly place, anyway |
62a8067a AV |
1242 | if (i->nr_segs == 1) |
1243 | return i->count; | |
7ff50620 | 1244 | if (unlikely(iov_iter_is_discard(i) || iov_iter_is_xarray(i))) |
9ea9ce04 | 1245 | return i->count; |
7ff50620 | 1246 | if (iov_iter_is_bvec(i)) |
62a8067a | 1247 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
ad0eab92 PM |
1248 | else |
1249 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
62a8067a AV |
1250 | } |
1251 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
1252 | ||
aa563d7b | 1253 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 1254 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
1255 | size_t count) |
1256 | { | |
aa563d7b DH |
1257 | WARN_ON(direction & ~(READ | WRITE)); |
1258 | i->type = ITER_KVEC | (direction & (READ | WRITE)); | |
05afcb77 | 1259 | i->kvec = kvec; |
abb78f87 AV |
1260 | i->nr_segs = nr_segs; |
1261 | i->iov_offset = 0; | |
1262 | i->count = count; | |
1263 | } | |
1264 | EXPORT_SYMBOL(iov_iter_kvec); | |
1265 | ||
aa563d7b | 1266 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1267 | const struct bio_vec *bvec, unsigned long nr_segs, |
1268 | size_t count) | |
1269 | { | |
aa563d7b DH |
1270 | WARN_ON(direction & ~(READ | WRITE)); |
1271 | i->type = ITER_BVEC | (direction & (READ | WRITE)); | |
05afcb77 AV |
1272 | i->bvec = bvec; |
1273 | i->nr_segs = nr_segs; | |
1274 | i->iov_offset = 0; | |
1275 | i->count = count; | |
1276 | } | |
1277 | EXPORT_SYMBOL(iov_iter_bvec); | |
1278 | ||
aa563d7b | 1279 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1280 | struct pipe_inode_info *pipe, |
1281 | size_t count) | |
1282 | { | |
aa563d7b | 1283 | BUG_ON(direction != READ); |
8cefc107 | 1284 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
aa563d7b | 1285 | i->type = ITER_PIPE | READ; |
241699cd | 1286 | i->pipe = pipe; |
8cefc107 | 1287 | i->head = pipe->head; |
241699cd AV |
1288 | i->iov_offset = 0; |
1289 | i->count = count; | |
8cefc107 | 1290 | i->start_head = i->head; |
241699cd AV |
1291 | } |
1292 | EXPORT_SYMBOL(iov_iter_pipe); | |
1293 | ||
7ff50620 DH |
1294 | /** |
1295 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray | |
1296 | * @i: The iterator to initialise. | |
1297 | * @direction: The direction of the transfer. | |
1298 | * @xarray: The xarray to access. | |
1299 | * @start: The start file position. | |
1300 | * @count: The size of the I/O buffer in bytes. | |
1301 | * | |
1302 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
1303 | * inode or to inject data into those pages. The pages *must* be prevented | |
1304 | * from evaporation, either by taking a ref on them or locking them by the | |
1305 | * caller. | |
1306 | */ | |
1307 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, | |
1308 | struct xarray *xarray, loff_t start, size_t count) | |
1309 | { | |
1310 | BUG_ON(direction & ~1); | |
1311 | i->type = ITER_XARRAY | (direction & (READ | WRITE)); | |
1312 | i->xarray = xarray; | |
1313 | i->xarray_start = start; | |
1314 | i->count = count; | |
1315 | i->iov_offset = 0; | |
1316 | } | |
1317 | EXPORT_SYMBOL(iov_iter_xarray); | |
1318 | ||
9ea9ce04 DH |
1319 | /** |
1320 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
1321 | * @i: The iterator to initialise. | |
1322 | * @direction: The direction of the transfer. | |
1323 | * @count: The size of the I/O buffer in bytes. | |
1324 | * | |
1325 | * Set up an I/O iterator that just discards everything that's written to it. | |
1326 | * It's only available as a READ iterator. | |
1327 | */ | |
1328 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
1329 | { | |
1330 | BUG_ON(direction != READ); | |
1331 | i->type = ITER_DISCARD | READ; | |
1332 | i->count = count; | |
1333 | i->iov_offset = 0; | |
1334 | } | |
1335 | EXPORT_SYMBOL(iov_iter_discard); | |
1336 | ||
62a8067a AV |
1337 | unsigned long iov_iter_alignment(const struct iov_iter *i) |
1338 | { | |
04a31165 AV |
1339 | unsigned long res = 0; |
1340 | size_t size = i->count; | |
1341 | ||
00e23707 | 1342 | if (unlikely(iov_iter_is_pipe(i))) { |
e0ff126e JK |
1343 | unsigned int p_mask = i->pipe->ring_size - 1; |
1344 | ||
8cefc107 | 1345 | if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) |
241699cd AV |
1346 | return size | i->iov_offset; |
1347 | return size; | |
1348 | } | |
04a31165 AV |
1349 | iterate_all_kinds(i, size, v, |
1350 | (res |= (unsigned long)v.iov_base | v.iov_len, 0), | |
a280455f | 1351 | res |= v.bv_offset | v.bv_len, |
7ff50620 DH |
1352 | res |= (unsigned long)v.iov_base | v.iov_len, |
1353 | res |= v.bv_offset | v.bv_len | |
04a31165 AV |
1354 | ) |
1355 | return res; | |
62a8067a AV |
1356 | } |
1357 | EXPORT_SYMBOL(iov_iter_alignment); | |
1358 | ||
357f435d AV |
1359 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1360 | { | |
33844e66 | 1361 | unsigned long res = 0; |
357f435d | 1362 | size_t size = i->count; |
357f435d | 1363 | |
9ea9ce04 | 1364 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1365 | WARN_ON(1); |
1366 | return ~0U; | |
1367 | } | |
1368 | ||
357f435d AV |
1369 | iterate_all_kinds(i, size, v, |
1370 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | | |
1371 | (size != v.iov_len ? size : 0), 0), | |
1372 | (res |= (!res ? 0 : (unsigned long)v.bv_offset) | | |
1373 | (size != v.bv_len ? size : 0)), | |
1374 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | | |
7ff50620 DH |
1375 | (size != v.iov_len ? size : 0)), |
1376 | (res |= (!res ? 0 : (unsigned long)v.bv_offset) | | |
1377 | (size != v.bv_len ? size : 0)) | |
357f435d | 1378 | ); |
33844e66 | 1379 | return res; |
357f435d AV |
1380 | } |
1381 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1382 | ||
e76b6312 | 1383 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
241699cd AV |
1384 | size_t maxsize, |
1385 | struct page **pages, | |
8cefc107 | 1386 | int iter_head, |
241699cd AV |
1387 | size_t *start) |
1388 | { | |
1389 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1390 | unsigned int p_mask = pipe->ring_size - 1; |
1391 | ssize_t n = push_pipe(i, maxsize, &iter_head, start); | |
241699cd AV |
1392 | if (!n) |
1393 | return -EFAULT; | |
1394 | ||
1395 | maxsize = n; | |
1396 | n += *start; | |
1689c73a | 1397 | while (n > 0) { |
8cefc107 DH |
1398 | get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); |
1399 | iter_head++; | |
241699cd AV |
1400 | n -= PAGE_SIZE; |
1401 | } | |
1402 | ||
1403 | return maxsize; | |
1404 | } | |
1405 | ||
1406 | static ssize_t pipe_get_pages(struct iov_iter *i, | |
1407 | struct page **pages, size_t maxsize, unsigned maxpages, | |
1408 | size_t *start) | |
1409 | { | |
8cefc107 | 1410 | unsigned int iter_head, npages; |
241699cd | 1411 | size_t capacity; |
241699cd | 1412 | |
33844e66 AV |
1413 | if (!maxsize) |
1414 | return 0; | |
1415 | ||
241699cd AV |
1416 | if (!sanity(i)) |
1417 | return -EFAULT; | |
1418 | ||
8cefc107 DH |
1419 | data_start(i, &iter_head, start); |
1420 | /* Amount of free space: some of this one + all after this one */ | |
1421 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
1422 | capacity = min(npages, maxpages) * PAGE_SIZE - *start; | |
241699cd | 1423 | |
8cefc107 | 1424 | return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); |
241699cd AV |
1425 | } |
1426 | ||
7ff50620 DH |
1427 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
1428 | pgoff_t index, unsigned int nr_pages) | |
1429 | { | |
1430 | XA_STATE(xas, xa, index); | |
1431 | struct page *page; | |
1432 | unsigned int ret = 0; | |
1433 | ||
1434 | rcu_read_lock(); | |
1435 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1436 | if (xas_retry(&xas, page)) | |
1437 | continue; | |
1438 | ||
1439 | /* Has the page moved or been split? */ | |
1440 | if (unlikely(page != xas_reload(&xas))) { | |
1441 | xas_reset(&xas); | |
1442 | continue; | |
1443 | } | |
1444 | ||
1445 | pages[ret] = find_subpage(page, xas.xa_index); | |
1446 | get_page(pages[ret]); | |
1447 | if (++ret == nr_pages) | |
1448 | break; | |
1449 | } | |
1450 | rcu_read_unlock(); | |
1451 | return ret; | |
1452 | } | |
1453 | ||
1454 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, | |
1455 | struct page **pages, size_t maxsize, | |
1456 | unsigned maxpages, size_t *_start_offset) | |
1457 | { | |
1458 | unsigned nr, offset; | |
1459 | pgoff_t index, count; | |
1460 | size_t size = maxsize, actual; | |
1461 | loff_t pos; | |
1462 | ||
1463 | if (!size || !maxpages) | |
1464 | return 0; | |
1465 | ||
1466 | pos = i->xarray_start + i->iov_offset; | |
1467 | index = pos >> PAGE_SHIFT; | |
1468 | offset = pos & ~PAGE_MASK; | |
1469 | *_start_offset = offset; | |
1470 | ||
1471 | count = 1; | |
1472 | if (size > PAGE_SIZE - offset) { | |
1473 | size -= PAGE_SIZE - offset; | |
1474 | count += size >> PAGE_SHIFT; | |
1475 | size &= ~PAGE_MASK; | |
1476 | if (size) | |
1477 | count++; | |
1478 | } | |
1479 | ||
1480 | if (count > maxpages) | |
1481 | count = maxpages; | |
1482 | ||
1483 | nr = iter_xarray_populate_pages(pages, i->xarray, index, count); | |
1484 | if (nr == 0) | |
1485 | return 0; | |
1486 | ||
1487 | actual = PAGE_SIZE * nr; | |
1488 | actual -= offset; | |
1489 | if (nr == count && size > 0) { | |
1490 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1491 | actual -= PAGE_SIZE - (last_offset + size); | |
1492 | } | |
1493 | return actual; | |
1494 | } | |
1495 | ||
62a8067a | 1496 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
2c80929c | 1497 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
1498 | size_t *start) |
1499 | { | |
e5393fae AV |
1500 | if (maxsize > i->count) |
1501 | maxsize = i->count; | |
1502 | ||
00e23707 | 1503 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1504 | return pipe_get_pages(i, pages, maxsize, maxpages, start); |
7ff50620 DH |
1505 | if (unlikely(iov_iter_is_xarray(i))) |
1506 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); | |
9ea9ce04 DH |
1507 | if (unlikely(iov_iter_is_discard(i))) |
1508 | return -EFAULT; | |
1509 | ||
e5393fae AV |
1510 | iterate_all_kinds(i, maxsize, v, ({ |
1511 | unsigned long addr = (unsigned long)v.iov_base; | |
1512 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
1513 | int n; | |
1514 | int res; | |
1515 | ||
1516 | if (len > maxpages * PAGE_SIZE) | |
1517 | len = maxpages * PAGE_SIZE; | |
1518 | addr &= ~(PAGE_SIZE - 1); | |
1519 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
73b0140b IW |
1520 | res = get_user_pages_fast(addr, n, |
1521 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, | |
1522 | pages); | |
e5393fae AV |
1523 | if (unlikely(res < 0)) |
1524 | return res; | |
1525 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
1526 | 0;}),({ | |
1527 | /* can't be more than PAGE_SIZE */ | |
1528 | *start = v.bv_offset; | |
1529 | get_page(*pages = v.bv_page); | |
1530 | return v.bv_len; | |
a280455f AV |
1531 | }),({ |
1532 | return -EFAULT; | |
7ff50620 DH |
1533 | }), |
1534 | 0 | |
e5393fae AV |
1535 | ) |
1536 | return 0; | |
62a8067a AV |
1537 | } |
1538 | EXPORT_SYMBOL(iov_iter_get_pages); | |
1539 | ||
1b17f1f2 AV |
1540 | static struct page **get_pages_array(size_t n) |
1541 | { | |
752ade68 | 1542 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); |
1b17f1f2 AV |
1543 | } |
1544 | ||
241699cd AV |
1545 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
1546 | struct page ***pages, size_t maxsize, | |
1547 | size_t *start) | |
1548 | { | |
1549 | struct page **p; | |
8cefc107 | 1550 | unsigned int iter_head, npages; |
d7760d63 | 1551 | ssize_t n; |
241699cd | 1552 | |
33844e66 AV |
1553 | if (!maxsize) |
1554 | return 0; | |
1555 | ||
241699cd AV |
1556 | if (!sanity(i)) |
1557 | return -EFAULT; | |
1558 | ||
8cefc107 DH |
1559 | data_start(i, &iter_head, start); |
1560 | /* Amount of free space: some of this one + all after this one */ | |
1561 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
241699cd AV |
1562 | n = npages * PAGE_SIZE - *start; |
1563 | if (maxsize > n) | |
1564 | maxsize = n; | |
1565 | else | |
1566 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); | |
1567 | p = get_pages_array(npages); | |
1568 | if (!p) | |
1569 | return -ENOMEM; | |
8cefc107 | 1570 | n = __pipe_get_pages(i, maxsize, p, iter_head, start); |
241699cd AV |
1571 | if (n > 0) |
1572 | *pages = p; | |
1573 | else | |
1574 | kvfree(p); | |
1575 | return n; | |
1576 | } | |
1577 | ||
7ff50620 DH |
1578 | static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, |
1579 | struct page ***pages, size_t maxsize, | |
1580 | size_t *_start_offset) | |
1581 | { | |
1582 | struct page **p; | |
1583 | unsigned nr, offset; | |
1584 | pgoff_t index, count; | |
1585 | size_t size = maxsize, actual; | |
1586 | loff_t pos; | |
1587 | ||
1588 | if (!size) | |
1589 | return 0; | |
1590 | ||
1591 | pos = i->xarray_start + i->iov_offset; | |
1592 | index = pos >> PAGE_SHIFT; | |
1593 | offset = pos & ~PAGE_MASK; | |
1594 | *_start_offset = offset; | |
1595 | ||
1596 | count = 1; | |
1597 | if (size > PAGE_SIZE - offset) { | |
1598 | size -= PAGE_SIZE - offset; | |
1599 | count += size >> PAGE_SHIFT; | |
1600 | size &= ~PAGE_MASK; | |
1601 | if (size) | |
1602 | count++; | |
1603 | } | |
1604 | ||
1605 | p = get_pages_array(count); | |
1606 | if (!p) | |
1607 | return -ENOMEM; | |
1608 | *pages = p; | |
1609 | ||
1610 | nr = iter_xarray_populate_pages(p, i->xarray, index, count); | |
1611 | if (nr == 0) | |
1612 | return 0; | |
1613 | ||
1614 | actual = PAGE_SIZE * nr; | |
1615 | actual -= offset; | |
1616 | if (nr == count && size > 0) { | |
1617 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1618 | actual -= PAGE_SIZE - (last_offset + size); | |
1619 | } | |
1620 | return actual; | |
1621 | } | |
1622 | ||
62a8067a AV |
1623 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
1624 | struct page ***pages, size_t maxsize, | |
1625 | size_t *start) | |
1626 | { | |
1b17f1f2 AV |
1627 | struct page **p; |
1628 | ||
1629 | if (maxsize > i->count) | |
1630 | maxsize = i->count; | |
1631 | ||
00e23707 | 1632 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1633 | return pipe_get_pages_alloc(i, pages, maxsize, start); |
7ff50620 DH |
1634 | if (unlikely(iov_iter_is_xarray(i))) |
1635 | return iter_xarray_get_pages_alloc(i, pages, maxsize, start); | |
9ea9ce04 DH |
1636 | if (unlikely(iov_iter_is_discard(i))) |
1637 | return -EFAULT; | |
1638 | ||
1b17f1f2 AV |
1639 | iterate_all_kinds(i, maxsize, v, ({ |
1640 | unsigned long addr = (unsigned long)v.iov_base; | |
1641 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
1642 | int n; | |
1643 | int res; | |
1644 | ||
1645 | addr &= ~(PAGE_SIZE - 1); | |
1646 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1647 | p = get_pages_array(n); | |
1648 | if (!p) | |
1649 | return -ENOMEM; | |
73b0140b IW |
1650 | res = get_user_pages_fast(addr, n, |
1651 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); | |
1b17f1f2 AV |
1652 | if (unlikely(res < 0)) { |
1653 | kvfree(p); | |
1654 | return res; | |
1655 | } | |
1656 | *pages = p; | |
1657 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
1658 | 0;}),({ | |
1659 | /* can't be more than PAGE_SIZE */ | |
1660 | *start = v.bv_offset; | |
1661 | *pages = p = get_pages_array(1); | |
1662 | if (!p) | |
1663 | return -ENOMEM; | |
1664 | get_page(*p = v.bv_page); | |
1665 | return v.bv_len; | |
a280455f AV |
1666 | }),({ |
1667 | return -EFAULT; | |
7ff50620 | 1668 | }), 0 |
1b17f1f2 AV |
1669 | ) |
1670 | return 0; | |
62a8067a AV |
1671 | } |
1672 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
1673 | ||
a604ec7e AV |
1674 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1675 | struct iov_iter *i) | |
1676 | { | |
1677 | char *to = addr; | |
1678 | __wsum sum, next; | |
1679 | size_t off = 0; | |
a604ec7e | 1680 | sum = *csum; |
9ea9ce04 | 1681 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1682 | WARN_ON(1); |
1683 | return 0; | |
1684 | } | |
a604ec7e | 1685 | iterate_and_advance(i, bytes, v, ({ |
cbbd26b8 | 1686 | next = csum_and_copy_from_user(v.iov_base, |
a604ec7e | 1687 | (to += v.iov_len) - v.iov_len, |
c693cc46 AV |
1688 | v.iov_len); |
1689 | if (next) { | |
a604ec7e AV |
1690 | sum = csum_block_add(sum, next, off); |
1691 | off += v.iov_len; | |
1692 | } | |
c693cc46 | 1693 | next ? 0 : v.iov_len; |
a604ec7e AV |
1694 | }), ({ |
1695 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1696 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
1697 | p + v.bv_offset, v.bv_len, | |
1698 | sum, off); | |
a604ec7e | 1699 | kunmap_atomic(p); |
a604ec7e AV |
1700 | off += v.bv_len; |
1701 | }),({ | |
f9152895 AV |
1702 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
1703 | v.iov_base, v.iov_len, | |
1704 | sum, off); | |
a604ec7e | 1705 | off += v.iov_len; |
7ff50620 DH |
1706 | }), ({ |
1707 | char *p = kmap_atomic(v.bv_page); | |
1708 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, | |
1709 | p + v.bv_offset, v.bv_len, | |
1710 | sum, off); | |
1711 | kunmap_atomic(p); | |
1712 | off += v.bv_len; | |
a604ec7e AV |
1713 | }) |
1714 | ) | |
1715 | *csum = sum; | |
1716 | return bytes; | |
1717 | } | |
1718 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1719 | ||
cbbd26b8 AV |
1720 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, |
1721 | struct iov_iter *i) | |
1722 | { | |
1723 | char *to = addr; | |
1724 | __wsum sum, next; | |
1725 | size_t off = 0; | |
1726 | sum = *csum; | |
9ea9ce04 | 1727 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
cbbd26b8 AV |
1728 | WARN_ON(1); |
1729 | return false; | |
1730 | } | |
1731 | if (unlikely(i->count < bytes)) | |
1732 | return false; | |
1733 | iterate_all_kinds(i, bytes, v, ({ | |
cbbd26b8 AV |
1734 | next = csum_and_copy_from_user(v.iov_base, |
1735 | (to += v.iov_len) - v.iov_len, | |
c693cc46 AV |
1736 | v.iov_len); |
1737 | if (!next) | |
cbbd26b8 AV |
1738 | return false; |
1739 | sum = csum_block_add(sum, next, off); | |
1740 | off += v.iov_len; | |
1741 | 0; | |
1742 | }), ({ | |
1743 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1744 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
1745 | p + v.bv_offset, v.bv_len, | |
1746 | sum, off); | |
cbbd26b8 | 1747 | kunmap_atomic(p); |
cbbd26b8 AV |
1748 | off += v.bv_len; |
1749 | }),({ | |
f9152895 AV |
1750 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
1751 | v.iov_base, v.iov_len, | |
1752 | sum, off); | |
cbbd26b8 | 1753 | off += v.iov_len; |
7ff50620 DH |
1754 | }), ({ |
1755 | char *p = kmap_atomic(v.bv_page); | |
1756 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, | |
1757 | p + v.bv_offset, v.bv_len, | |
1758 | sum, off); | |
1759 | kunmap_atomic(p); | |
1760 | off += v.bv_len; | |
cbbd26b8 AV |
1761 | }) |
1762 | ) | |
1763 | *csum = sum; | |
1764 | iov_iter_advance(i, bytes); | |
1765 | return true; | |
1766 | } | |
1767 | EXPORT_SYMBOL(csum_and_copy_from_iter_full); | |
1768 | ||
52cbd23a | 1769 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
a604ec7e AV |
1770 | struct iov_iter *i) |
1771 | { | |
52cbd23a | 1772 | struct csum_state *csstate = _csstate; |
36f7a8a4 | 1773 | const char *from = addr; |
a604ec7e | 1774 | __wsum sum, next; |
52cbd23a | 1775 | size_t off; |
78e1f386 AV |
1776 | |
1777 | if (unlikely(iov_iter_is_pipe(i))) | |
52cbd23a | 1778 | return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); |
78e1f386 | 1779 | |
52cbd23a WB |
1780 | sum = csstate->csum; |
1781 | off = csstate->off; | |
78e1f386 | 1782 | if (unlikely(iov_iter_is_discard(i))) { |
241699cd AV |
1783 | WARN_ON(1); /* for now */ |
1784 | return 0; | |
1785 | } | |
a604ec7e | 1786 | iterate_and_advance(i, bytes, v, ({ |
a604ec7e | 1787 | next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, |
cbbd26b8 | 1788 | v.iov_base, |
c693cc46 AV |
1789 | v.iov_len); |
1790 | if (next) { | |
a604ec7e AV |
1791 | sum = csum_block_add(sum, next, off); |
1792 | off += v.iov_len; | |
1793 | } | |
c693cc46 | 1794 | next ? 0 : v.iov_len; |
a604ec7e AV |
1795 | }), ({ |
1796 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1797 | sum = csum_and_memcpy(p + v.bv_offset, |
1798 | (from += v.bv_len) - v.bv_len, | |
1799 | v.bv_len, sum, off); | |
a604ec7e | 1800 | kunmap_atomic(p); |
a604ec7e AV |
1801 | off += v.bv_len; |
1802 | }),({ | |
f9152895 AV |
1803 | sum = csum_and_memcpy(v.iov_base, |
1804 | (from += v.iov_len) - v.iov_len, | |
1805 | v.iov_len, sum, off); | |
a604ec7e | 1806 | off += v.iov_len; |
7ff50620 DH |
1807 | }), ({ |
1808 | char *p = kmap_atomic(v.bv_page); | |
1809 | sum = csum_and_memcpy(p + v.bv_offset, | |
1810 | (from += v.bv_len) - v.bv_len, | |
1811 | v.bv_len, sum, off); | |
1812 | kunmap_atomic(p); | |
1813 | off += v.bv_len; | |
a604ec7e AV |
1814 | }) |
1815 | ) | |
52cbd23a WB |
1816 | csstate->csum = sum; |
1817 | csstate->off = off; | |
a604ec7e AV |
1818 | return bytes; |
1819 | } | |
1820 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1821 | ||
d05f4435 SG |
1822 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
1823 | struct iov_iter *i) | |
1824 | { | |
7999096f | 1825 | #ifdef CONFIG_CRYPTO_HASH |
d05f4435 SG |
1826 | struct ahash_request *hash = hashp; |
1827 | struct scatterlist sg; | |
1828 | size_t copied; | |
1829 | ||
1830 | copied = copy_to_iter(addr, bytes, i); | |
1831 | sg_init_one(&sg, addr, copied); | |
1832 | ahash_request_set_crypt(hash, &sg, NULL, copied); | |
1833 | crypto_ahash_update(hash); | |
1834 | return copied; | |
27fad74a Y |
1835 | #else |
1836 | return 0; | |
1837 | #endif | |
d05f4435 SG |
1838 | } |
1839 | EXPORT_SYMBOL(hash_and_copy_to_iter); | |
1840 | ||
62a8067a AV |
1841 | int iov_iter_npages(const struct iov_iter *i, int maxpages) |
1842 | { | |
e0f2dc40 AV |
1843 | size_t size = i->count; |
1844 | int npages = 0; | |
1845 | ||
1846 | if (!size) | |
1847 | return 0; | |
9ea9ce04 DH |
1848 | if (unlikely(iov_iter_is_discard(i))) |
1849 | return 0; | |
e0f2dc40 | 1850 | |
00e23707 | 1851 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd | 1852 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 | 1853 | unsigned int iter_head; |
241699cd | 1854 | size_t off; |
241699cd AV |
1855 | |
1856 | if (!sanity(i)) | |
1857 | return 0; | |
1858 | ||
8cefc107 | 1859 | data_start(i, &iter_head, &off); |
241699cd | 1860 | /* some of this one + all after this one */ |
8cefc107 | 1861 | npages = pipe_space_for_user(iter_head, pipe->tail, pipe); |
241699cd AV |
1862 | if (npages >= maxpages) |
1863 | return maxpages; | |
7ff50620 DH |
1864 | } else if (unlikely(iov_iter_is_xarray(i))) { |
1865 | unsigned offset; | |
1866 | ||
1867 | offset = (i->xarray_start + i->iov_offset) & ~PAGE_MASK; | |
1868 | ||
1869 | npages = 1; | |
1870 | if (size > PAGE_SIZE - offset) { | |
1871 | size -= PAGE_SIZE - offset; | |
1872 | npages += size >> PAGE_SHIFT; | |
1873 | size &= ~PAGE_MASK; | |
1874 | if (size) | |
1875 | npages++; | |
1876 | } | |
1877 | if (npages >= maxpages) | |
1878 | return maxpages; | |
241699cd | 1879 | } else iterate_all_kinds(i, size, v, ({ |
e0f2dc40 AV |
1880 | unsigned long p = (unsigned long)v.iov_base; |
1881 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
1882 | - p / PAGE_SIZE; | |
1883 | if (npages >= maxpages) | |
1884 | return maxpages; | |
1885 | 0;}),({ | |
1886 | npages++; | |
1887 | if (npages >= maxpages) | |
1888 | return maxpages; | |
a280455f AV |
1889 | }),({ |
1890 | unsigned long p = (unsigned long)v.iov_base; | |
1891 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
1892 | - p / PAGE_SIZE; | |
1893 | if (npages >= maxpages) | |
1894 | return maxpages; | |
7ff50620 DH |
1895 | }), |
1896 | 0 | |
e0f2dc40 AV |
1897 | ) |
1898 | return npages; | |
62a8067a | 1899 | } |
f67da30c | 1900 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1901 | |
1902 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1903 | { | |
1904 | *new = *old; | |
00e23707 | 1905 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1906 | WARN_ON(1); |
1907 | return NULL; | |
1908 | } | |
7ff50620 | 1909 | if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) |
9ea9ce04 | 1910 | return NULL; |
00e23707 | 1911 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1912 | return new->bvec = kmemdup(new->bvec, |
1913 | new->nr_segs * sizeof(struct bio_vec), | |
1914 | flags); | |
1915 | else | |
1916 | /* iovec and kvec have identical layout */ | |
1917 | return new->iov = kmemdup(new->iov, | |
1918 | new->nr_segs * sizeof(struct iovec), | |
1919 | flags); | |
1920 | } | |
1921 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1922 | |
bfdc5970 CH |
1923 | static int copy_compat_iovec_from_user(struct iovec *iov, |
1924 | const struct iovec __user *uvec, unsigned long nr_segs) | |
1925 | { | |
1926 | const struct compat_iovec __user *uiov = | |
1927 | (const struct compat_iovec __user *)uvec; | |
1928 | int ret = -EFAULT, i; | |
1929 | ||
a959a978 | 1930 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
1931 | return -EFAULT; |
1932 | ||
1933 | for (i = 0; i < nr_segs; i++) { | |
1934 | compat_uptr_t buf; | |
1935 | compat_ssize_t len; | |
1936 | ||
1937 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); | |
1938 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); | |
1939 | ||
1940 | /* check for compat_size_t not fitting in compat_ssize_t .. */ | |
1941 | if (len < 0) { | |
1942 | ret = -EINVAL; | |
1943 | goto uaccess_end; | |
1944 | } | |
1945 | iov[i].iov_base = compat_ptr(buf); | |
1946 | iov[i].iov_len = len; | |
1947 | } | |
1948 | ||
1949 | ret = 0; | |
1950 | uaccess_end: | |
1951 | user_access_end(); | |
1952 | return ret; | |
1953 | } | |
1954 | ||
1955 | static int copy_iovec_from_user(struct iovec *iov, | |
1956 | const struct iovec __user *uvec, unsigned long nr_segs) | |
fb041b59 DL |
1957 | { |
1958 | unsigned long seg; | |
fb041b59 | 1959 | |
bfdc5970 CH |
1960 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
1961 | return -EFAULT; | |
1962 | for (seg = 0; seg < nr_segs; seg++) { | |
1963 | if ((ssize_t)iov[seg].iov_len < 0) | |
1964 | return -EINVAL; | |
fb041b59 DL |
1965 | } |
1966 | ||
bfdc5970 CH |
1967 | return 0; |
1968 | } | |
1969 | ||
1970 | struct iovec *iovec_from_user(const struct iovec __user *uvec, | |
1971 | unsigned long nr_segs, unsigned long fast_segs, | |
1972 | struct iovec *fast_iov, bool compat) | |
1973 | { | |
1974 | struct iovec *iov = fast_iov; | |
1975 | int ret; | |
1976 | ||
fb041b59 | 1977 | /* |
bfdc5970 CH |
1978 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
1979 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
1980 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 1981 | */ |
bfdc5970 CH |
1982 | if (nr_segs == 0) |
1983 | return iov; | |
1984 | if (nr_segs > UIO_MAXIOV) | |
1985 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
1986 | if (nr_segs > fast_segs) { |
1987 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
1988 | if (!iov) |
1989 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 1990 | } |
bfdc5970 CH |
1991 | |
1992 | if (compat) | |
1993 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); | |
1994 | else | |
1995 | ret = copy_iovec_from_user(iov, uvec, nr_segs); | |
1996 | if (ret) { | |
1997 | if (iov != fast_iov) | |
1998 | kfree(iov); | |
1999 | return ERR_PTR(ret); | |
2000 | } | |
2001 | ||
2002 | return iov; | |
2003 | } | |
2004 | ||
2005 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
2006 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
2007 | struct iov_iter *i, bool compat) | |
2008 | { | |
2009 | ssize_t total_len = 0; | |
2010 | unsigned long seg; | |
2011 | struct iovec *iov; | |
2012 | ||
2013 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); | |
2014 | if (IS_ERR(iov)) { | |
2015 | *iovp = NULL; | |
2016 | return PTR_ERR(iov); | |
fb041b59 DL |
2017 | } |
2018 | ||
2019 | /* | |
bfdc5970 CH |
2020 | * According to the Single Unix Specification we should return EINVAL if |
2021 | * an element length is < 0 when cast to ssize_t or if the total length | |
2022 | * would overflow the ssize_t return value of the system call. | |
fb041b59 DL |
2023 | * |
2024 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
2025 | * overflow case. | |
2026 | */ | |
fb041b59 | 2027 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
2028 | ssize_t len = (ssize_t)iov[seg].iov_len; |
2029 | ||
bfdc5970 CH |
2030 | if (!access_ok(iov[seg].iov_base, len)) { |
2031 | if (iov != *iovp) | |
2032 | kfree(iov); | |
2033 | *iovp = NULL; | |
2034 | return -EFAULT; | |
fb041b59 | 2035 | } |
bfdc5970 CH |
2036 | |
2037 | if (len > MAX_RW_COUNT - total_len) { | |
2038 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
2039 | iov[seg].iov_len = len; |
2040 | } | |
bfdc5970 | 2041 | total_len += len; |
fb041b59 | 2042 | } |
bfdc5970 CH |
2043 | |
2044 | iov_iter_init(i, type, iov, nr_segs, total_len); | |
2045 | if (iov == *iovp) | |
2046 | *iovp = NULL; | |
2047 | else | |
2048 | *iovp = iov; | |
2049 | return total_len; | |
fb041b59 DL |
2050 | } |
2051 | ||
ffecee4f VN |
2052 | /** |
2053 | * import_iovec() - Copy an array of &struct iovec from userspace | |
2054 | * into the kernel, check that it is valid, and initialize a new | |
2055 | * &struct iov_iter iterator to access it. | |
2056 | * | |
2057 | * @type: One of %READ or %WRITE. | |
bfdc5970 | 2058 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
2059 | * @nr_segs: Number of elements in userspace array. |
2060 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 2061 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
2062 | * on-stack) kernel array. |
2063 | * @i: Pointer to iterator that will be initialized on success. | |
2064 | * | |
2065 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
2066 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
2067 | * array will be allocated and the result placed in *@iov. This means that | |
2068 | * the caller may call kfree() on *@iov regardless of whether the small | |
2069 | * on-stack array was used or not (and regardless of whether this function | |
2070 | * returns an error or not). | |
2071 | * | |
87e5e6da | 2072 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 2073 | */ |
bfdc5970 | 2074 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 2075 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 2076 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 2077 | { |
89cd35c5 CH |
2078 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
2079 | in_compat_syscall()); | |
bc917be8 AV |
2080 | } |
2081 | EXPORT_SYMBOL(import_iovec); | |
2082 | ||
bc917be8 AV |
2083 | int import_single_range(int rw, void __user *buf, size_t len, |
2084 | struct iovec *iov, struct iov_iter *i) | |
2085 | { | |
2086 | if (len > MAX_RW_COUNT) | |
2087 | len = MAX_RW_COUNT; | |
96d4f267 | 2088 | if (unlikely(!access_ok(buf, len))) |
bc917be8 AV |
2089 | return -EFAULT; |
2090 | ||
2091 | iov->iov_base = buf; | |
2092 | iov->iov_len = len; | |
2093 | iov_iter_init(i, rw, iov, 1, len); | |
2094 | return 0; | |
2095 | } | |
e1267585 | 2096 | EXPORT_SYMBOL(import_single_range); |
09cf698a AV |
2097 | |
2098 | int iov_iter_for_each_range(struct iov_iter *i, size_t bytes, | |
2099 | int (*f)(struct kvec *vec, void *context), | |
2100 | void *context) | |
2101 | { | |
2102 | struct kvec w; | |
2103 | int err = -EINVAL; | |
2104 | if (!bytes) | |
2105 | return 0; | |
2106 | ||
2107 | iterate_all_kinds(i, bytes, v, -EINVAL, ({ | |
2108 | w.iov_base = kmap(v.bv_page) + v.bv_offset; | |
2109 | w.iov_len = v.bv_len; | |
2110 | err = f(&w, context); | |
2111 | kunmap(v.bv_page); | |
2112 | err;}), ({ | |
2113 | w = v; | |
7ff50620 DH |
2114 | err = f(&w, context);}), ({ |
2115 | w.iov_base = kmap(v.bv_page) + v.bv_offset; | |
2116 | w.iov_len = v.bv_len; | |
2117 | err = f(&w, context); | |
2118 | kunmap(v.bv_page); | |
2119 | err;}) | |
09cf698a AV |
2120 | ) |
2121 | return err; | |
2122 | } | |
2123 | EXPORT_SYMBOL(iov_iter_for_each_range); |