Commit | Line | Data |
---|---|---|
457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
7999096f | 2 | #include <crypto/hash.h> |
4f18cd31 | 3 | #include <linux/export.h> |
2f8b5444 | 4 | #include <linux/bvec.h> |
4d0e9df5 | 5 | #include <linux/fault-inject-usercopy.h> |
4f18cd31 AV |
6 | #include <linux/uio.h> |
7 | #include <linux/pagemap.h> | |
28961998 | 8 | #include <linux/highmem.h> |
91f79c43 AV |
9 | #include <linux/slab.h> |
10 | #include <linux/vmalloc.h> | |
241699cd | 11 | #include <linux/splice.h> |
bfdc5970 | 12 | #include <linux/compat.h> |
a604ec7e | 13 | #include <net/checksum.h> |
d05f4435 | 14 | #include <linux/scatterlist.h> |
d0ef4c36 | 15 | #include <linux/instrumented.h> |
4f18cd31 | 16 | |
241699cd AV |
17 | #define PIPE_PARANOIA /* for now */ |
18 | ||
04a31165 AV |
19 | #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ |
20 | size_t left; \ | |
21 | size_t wanted = n; \ | |
22 | __p = i->iov; \ | |
23 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
24 | if (likely(__v.iov_len)) { \ | |
25 | __v.iov_base = __p->iov_base + skip; \ | |
26 | left = (STEP); \ | |
27 | __v.iov_len -= left; \ | |
28 | skip += __v.iov_len; \ | |
29 | n -= __v.iov_len; \ | |
30 | } else { \ | |
31 | left = 0; \ | |
32 | } \ | |
33 | while (unlikely(!left && n)) { \ | |
34 | __p++; \ | |
35 | __v.iov_len = min(n, __p->iov_len); \ | |
36 | if (unlikely(!__v.iov_len)) \ | |
37 | continue; \ | |
38 | __v.iov_base = __p->iov_base; \ | |
39 | left = (STEP); \ | |
40 | __v.iov_len -= left; \ | |
41 | skip = __v.iov_len; \ | |
42 | n -= __v.iov_len; \ | |
43 | } \ | |
44 | n = wanted - n; \ | |
45 | } | |
46 | ||
a280455f AV |
47 | #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ |
48 | size_t wanted = n; \ | |
49 | __p = i->kvec; \ | |
50 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
51 | if (likely(__v.iov_len)) { \ | |
52 | __v.iov_base = __p->iov_base + skip; \ | |
53 | (void)(STEP); \ | |
54 | skip += __v.iov_len; \ | |
55 | n -= __v.iov_len; \ | |
56 | } \ | |
57 | while (unlikely(n)) { \ | |
58 | __p++; \ | |
59 | __v.iov_len = min(n, __p->iov_len); \ | |
60 | if (unlikely(!__v.iov_len)) \ | |
61 | continue; \ | |
62 | __v.iov_base = __p->iov_base; \ | |
63 | (void)(STEP); \ | |
64 | skip = __v.iov_len; \ | |
65 | n -= __v.iov_len; \ | |
66 | } \ | |
67 | n = wanted; \ | |
68 | } | |
69 | ||
1bdc76ae ML |
70 | #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ |
71 | struct bvec_iter __start; \ | |
72 | __start.bi_size = n; \ | |
73 | __start.bi_bvec_done = skip; \ | |
74 | __start.bi_idx = 0; \ | |
75 | for_each_bvec(__v, i->bvec, __bi, __start) { \ | |
04a31165 | 76 | (void)(STEP); \ |
04a31165 | 77 | } \ |
04a31165 AV |
78 | } |
79 | ||
7ff50620 DH |
80 | #define iterate_xarray(i, n, __v, skip, STEP) { \ |
81 | struct page *head = NULL; \ | |
82 | size_t wanted = n, seg, offset; \ | |
83 | loff_t start = i->xarray_start + skip; \ | |
84 | pgoff_t index = start >> PAGE_SHIFT; \ | |
85 | int j; \ | |
86 | \ | |
87 | XA_STATE(xas, i->xarray, index); \ | |
88 | \ | |
89 | rcu_read_lock(); \ | |
90 | xas_for_each(&xas, head, ULONG_MAX) { \ | |
91 | if (xas_retry(&xas, head)) \ | |
92 | continue; \ | |
93 | if (WARN_ON(xa_is_value(head))) \ | |
94 | break; \ | |
95 | if (WARN_ON(PageHuge(head))) \ | |
96 | break; \ | |
97 | for (j = (head->index < index) ? index - head->index : 0; \ | |
98 | j < thp_nr_pages(head); j++) { \ | |
99 | __v.bv_page = head + j; \ | |
100 | offset = (i->xarray_start + skip) & ~PAGE_MASK; \ | |
101 | seg = PAGE_SIZE - offset; \ | |
102 | __v.bv_offset = offset; \ | |
103 | __v.bv_len = min(n, seg); \ | |
104 | (void)(STEP); \ | |
105 | n -= __v.bv_len; \ | |
106 | skip += __v.bv_len; \ | |
107 | if (n == 0) \ | |
108 | break; \ | |
109 | } \ | |
110 | if (n == 0) \ | |
111 | break; \ | |
112 | } \ | |
113 | rcu_read_unlock(); \ | |
114 | n = wanted - n; \ | |
115 | } | |
116 | ||
117 | #define iterate_all_kinds(i, n, v, I, B, K, X) { \ | |
33844e66 AV |
118 | if (likely(n)) { \ |
119 | size_t skip = i->iov_offset; \ | |
120 | if (unlikely(i->type & ITER_BVEC)) { \ | |
121 | struct bio_vec v; \ | |
122 | struct bvec_iter __bi; \ | |
123 | iterate_bvec(i, n, v, __bi, skip, (B)) \ | |
124 | } else if (unlikely(i->type & ITER_KVEC)) { \ | |
125 | const struct kvec *kvec; \ | |
126 | struct kvec v; \ | |
127 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
9ea9ce04 | 128 | } else if (unlikely(i->type & ITER_DISCARD)) { \ |
7ff50620 DH |
129 | } else if (unlikely(i->type & ITER_XARRAY)) { \ |
130 | struct bio_vec v; \ | |
131 | iterate_xarray(i, n, v, skip, (X)); \ | |
33844e66 AV |
132 | } else { \ |
133 | const struct iovec *iov; \ | |
134 | struct iovec v; \ | |
135 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
136 | } \ | |
04a31165 AV |
137 | } \ |
138 | } | |
139 | ||
7ff50620 | 140 | #define iterate_and_advance(i, n, v, I, B, K, X) { \ |
dd254f5a AV |
141 | if (unlikely(i->count < n)) \ |
142 | n = i->count; \ | |
19f18459 | 143 | if (i->count) { \ |
dd254f5a AV |
144 | size_t skip = i->iov_offset; \ |
145 | if (unlikely(i->type & ITER_BVEC)) { \ | |
1bdc76ae | 146 | const struct bio_vec *bvec = i->bvec; \ |
dd254f5a | 147 | struct bio_vec v; \ |
1bdc76ae ML |
148 | struct bvec_iter __bi; \ |
149 | iterate_bvec(i, n, v, __bi, skip, (B)) \ | |
150 | i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ | |
151 | i->nr_segs -= i->bvec - bvec; \ | |
152 | skip = __bi.bi_bvec_done; \ | |
dd254f5a AV |
153 | } else if (unlikely(i->type & ITER_KVEC)) { \ |
154 | const struct kvec *kvec; \ | |
155 | struct kvec v; \ | |
156 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
157 | if (skip == kvec->iov_len) { \ | |
158 | kvec++; \ | |
159 | skip = 0; \ | |
160 | } \ | |
161 | i->nr_segs -= kvec - i->kvec; \ | |
162 | i->kvec = kvec; \ | |
9ea9ce04 DH |
163 | } else if (unlikely(i->type & ITER_DISCARD)) { \ |
164 | skip += n; \ | |
7ff50620 DH |
165 | } else if (unlikely(i->type & ITER_XARRAY)) { \ |
166 | struct bio_vec v; \ | |
167 | iterate_xarray(i, n, v, skip, (X)) \ | |
dd254f5a AV |
168 | } else { \ |
169 | const struct iovec *iov; \ | |
170 | struct iovec v; \ | |
171 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
172 | if (skip == iov->iov_len) { \ | |
173 | iov++; \ | |
174 | skip = 0; \ | |
175 | } \ | |
176 | i->nr_segs -= iov - i->iov; \ | |
177 | i->iov = iov; \ | |
7ce2a91e | 178 | } \ |
dd254f5a AV |
179 | i->count -= n; \ |
180 | i->iov_offset = skip; \ | |
7ce2a91e | 181 | } \ |
7ce2a91e AV |
182 | } |
183 | ||
09fc68dc AV |
184 | static int copyout(void __user *to, const void *from, size_t n) |
185 | { | |
4d0e9df5 AL |
186 | if (should_fail_usercopy()) |
187 | return n; | |
96d4f267 | 188 | if (access_ok(to, n)) { |
d0ef4c36 | 189 | instrument_copy_to_user(to, from, n); |
09fc68dc AV |
190 | n = raw_copy_to_user(to, from, n); |
191 | } | |
192 | return n; | |
193 | } | |
194 | ||
195 | static int copyin(void *to, const void __user *from, size_t n) | |
196 | { | |
4d0e9df5 AL |
197 | if (should_fail_usercopy()) |
198 | return n; | |
96d4f267 | 199 | if (access_ok(from, n)) { |
d0ef4c36 | 200 | instrument_copy_from_user(to, from, n); |
09fc68dc AV |
201 | n = raw_copy_from_user(to, from, n); |
202 | } | |
203 | return n; | |
204 | } | |
205 | ||
62a8067a | 206 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
207 | struct iov_iter *i) |
208 | { | |
209 | size_t skip, copy, left, wanted; | |
210 | const struct iovec *iov; | |
211 | char __user *buf; | |
212 | void *kaddr, *from; | |
213 | ||
214 | if (unlikely(bytes > i->count)) | |
215 | bytes = i->count; | |
216 | ||
217 | if (unlikely(!bytes)) | |
218 | return 0; | |
219 | ||
09fc68dc | 220 | might_fault(); |
4f18cd31 AV |
221 | wanted = bytes; |
222 | iov = i->iov; | |
223 | skip = i->iov_offset; | |
224 | buf = iov->iov_base + skip; | |
225 | copy = min(bytes, iov->iov_len - skip); | |
226 | ||
3fa6c507 | 227 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { |
4f18cd31 AV |
228 | kaddr = kmap_atomic(page); |
229 | from = kaddr + offset; | |
230 | ||
231 | /* first chunk, usually the only one */ | |
09fc68dc | 232 | left = copyout(buf, from, copy); |
4f18cd31 AV |
233 | copy -= left; |
234 | skip += copy; | |
235 | from += copy; | |
236 | bytes -= copy; | |
237 | ||
238 | while (unlikely(!left && bytes)) { | |
239 | iov++; | |
240 | buf = iov->iov_base; | |
241 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 242 | left = copyout(buf, from, copy); |
4f18cd31 AV |
243 | copy -= left; |
244 | skip = copy; | |
245 | from += copy; | |
246 | bytes -= copy; | |
247 | } | |
248 | if (likely(!bytes)) { | |
249 | kunmap_atomic(kaddr); | |
250 | goto done; | |
251 | } | |
252 | offset = from - kaddr; | |
253 | buf += copy; | |
254 | kunmap_atomic(kaddr); | |
255 | copy = min(bytes, iov->iov_len - skip); | |
256 | } | |
257 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 258 | |
4f18cd31 AV |
259 | kaddr = kmap(page); |
260 | from = kaddr + offset; | |
09fc68dc | 261 | left = copyout(buf, from, copy); |
4f18cd31 AV |
262 | copy -= left; |
263 | skip += copy; | |
264 | from += copy; | |
265 | bytes -= copy; | |
266 | while (unlikely(!left && bytes)) { | |
267 | iov++; | |
268 | buf = iov->iov_base; | |
269 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 270 | left = copyout(buf, from, copy); |
4f18cd31 AV |
271 | copy -= left; |
272 | skip = copy; | |
273 | from += copy; | |
274 | bytes -= copy; | |
275 | } | |
276 | kunmap(page); | |
3fa6c507 | 277 | |
4f18cd31 | 278 | done: |
81055e58 AV |
279 | if (skip == iov->iov_len) { |
280 | iov++; | |
281 | skip = 0; | |
282 | } | |
4f18cd31 AV |
283 | i->count -= wanted - bytes; |
284 | i->nr_segs -= iov - i->iov; | |
285 | i->iov = iov; | |
286 | i->iov_offset = skip; | |
287 | return wanted - bytes; | |
288 | } | |
4f18cd31 | 289 | |
62a8067a | 290 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
291 | struct iov_iter *i) |
292 | { | |
293 | size_t skip, copy, left, wanted; | |
294 | const struct iovec *iov; | |
295 | char __user *buf; | |
296 | void *kaddr, *to; | |
297 | ||
298 | if (unlikely(bytes > i->count)) | |
299 | bytes = i->count; | |
300 | ||
301 | if (unlikely(!bytes)) | |
302 | return 0; | |
303 | ||
09fc68dc | 304 | might_fault(); |
f0d1bec9 AV |
305 | wanted = bytes; |
306 | iov = i->iov; | |
307 | skip = i->iov_offset; | |
308 | buf = iov->iov_base + skip; | |
309 | copy = min(bytes, iov->iov_len - skip); | |
310 | ||
3fa6c507 | 311 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { |
f0d1bec9 AV |
312 | kaddr = kmap_atomic(page); |
313 | to = kaddr + offset; | |
314 | ||
315 | /* first chunk, usually the only one */ | |
09fc68dc | 316 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
317 | copy -= left; |
318 | skip += copy; | |
319 | to += copy; | |
320 | bytes -= copy; | |
321 | ||
322 | while (unlikely(!left && bytes)) { | |
323 | iov++; | |
324 | buf = iov->iov_base; | |
325 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 326 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
327 | copy -= left; |
328 | skip = copy; | |
329 | to += copy; | |
330 | bytes -= copy; | |
331 | } | |
332 | if (likely(!bytes)) { | |
333 | kunmap_atomic(kaddr); | |
334 | goto done; | |
335 | } | |
336 | offset = to - kaddr; | |
337 | buf += copy; | |
338 | kunmap_atomic(kaddr); | |
339 | copy = min(bytes, iov->iov_len - skip); | |
340 | } | |
341 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 342 | |
f0d1bec9 AV |
343 | kaddr = kmap(page); |
344 | to = kaddr + offset; | |
09fc68dc | 345 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
346 | copy -= left; |
347 | skip += copy; | |
348 | to += copy; | |
349 | bytes -= copy; | |
350 | while (unlikely(!left && bytes)) { | |
351 | iov++; | |
352 | buf = iov->iov_base; | |
353 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 354 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
355 | copy -= left; |
356 | skip = copy; | |
357 | to += copy; | |
358 | bytes -= copy; | |
359 | } | |
360 | kunmap(page); | |
3fa6c507 | 361 | |
f0d1bec9 | 362 | done: |
81055e58 AV |
363 | if (skip == iov->iov_len) { |
364 | iov++; | |
365 | skip = 0; | |
366 | } | |
f0d1bec9 AV |
367 | i->count -= wanted - bytes; |
368 | i->nr_segs -= iov - i->iov; | |
369 | i->iov = iov; | |
370 | i->iov_offset = skip; | |
371 | return wanted - bytes; | |
372 | } | |
f0d1bec9 | 373 | |
241699cd AV |
374 | #ifdef PIPE_PARANOIA |
375 | static bool sanity(const struct iov_iter *i) | |
376 | { | |
377 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
378 | unsigned int p_head = pipe->head; |
379 | unsigned int p_tail = pipe->tail; | |
380 | unsigned int p_mask = pipe->ring_size - 1; | |
381 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); | |
382 | unsigned int i_head = i->head; | |
383 | unsigned int idx; | |
384 | ||
241699cd AV |
385 | if (i->iov_offset) { |
386 | struct pipe_buffer *p; | |
8cefc107 | 387 | if (unlikely(p_occupancy == 0)) |
241699cd | 388 | goto Bad; // pipe must be non-empty |
8cefc107 | 389 | if (unlikely(i_head != p_head - 1)) |
241699cd AV |
390 | goto Bad; // must be at the last buffer... |
391 | ||
8cefc107 | 392 | p = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
393 | if (unlikely(p->offset + p->len != i->iov_offset)) |
394 | goto Bad; // ... at the end of segment | |
395 | } else { | |
8cefc107 | 396 | if (i_head != p_head) |
241699cd AV |
397 | goto Bad; // must be right after the last buffer |
398 | } | |
399 | return true; | |
400 | Bad: | |
8cefc107 DH |
401 | printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); |
402 | printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", | |
403 | p_head, p_tail, pipe->ring_size); | |
404 | for (idx = 0; idx < pipe->ring_size; idx++) | |
241699cd AV |
405 | printk(KERN_ERR "[%p %p %d %d]\n", |
406 | pipe->bufs[idx].ops, | |
407 | pipe->bufs[idx].page, | |
408 | pipe->bufs[idx].offset, | |
409 | pipe->bufs[idx].len); | |
410 | WARN_ON(1); | |
411 | return false; | |
412 | } | |
413 | #else | |
414 | #define sanity(i) true | |
415 | #endif | |
416 | ||
241699cd AV |
417 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
418 | struct iov_iter *i) | |
419 | { | |
420 | struct pipe_inode_info *pipe = i->pipe; | |
421 | struct pipe_buffer *buf; | |
8cefc107 DH |
422 | unsigned int p_tail = pipe->tail; |
423 | unsigned int p_mask = pipe->ring_size - 1; | |
424 | unsigned int i_head = i->head; | |
241699cd | 425 | size_t off; |
241699cd AV |
426 | |
427 | if (unlikely(bytes > i->count)) | |
428 | bytes = i->count; | |
429 | ||
430 | if (unlikely(!bytes)) | |
431 | return 0; | |
432 | ||
433 | if (!sanity(i)) | |
434 | return 0; | |
435 | ||
436 | off = i->iov_offset; | |
8cefc107 | 437 | buf = &pipe->bufs[i_head & p_mask]; |
241699cd AV |
438 | if (off) { |
439 | if (offset == off && buf->page == page) { | |
440 | /* merge with the last one */ | |
441 | buf->len += bytes; | |
442 | i->iov_offset += bytes; | |
443 | goto out; | |
444 | } | |
8cefc107 DH |
445 | i_head++; |
446 | buf = &pipe->bufs[i_head & p_mask]; | |
241699cd | 447 | } |
6718b6f8 | 448 | if (pipe_full(i_head, p_tail, pipe->max_usage)) |
241699cd | 449 | return 0; |
8cefc107 | 450 | |
241699cd | 451 | buf->ops = &page_cache_pipe_buf_ops; |
8cefc107 DH |
452 | get_page(page); |
453 | buf->page = page; | |
241699cd AV |
454 | buf->offset = offset; |
455 | buf->len = bytes; | |
8cefc107 DH |
456 | |
457 | pipe->head = i_head + 1; | |
241699cd | 458 | i->iov_offset = offset + bytes; |
8cefc107 | 459 | i->head = i_head; |
241699cd AV |
460 | out: |
461 | i->count -= bytes; | |
462 | return bytes; | |
463 | } | |
464 | ||
171a0203 AA |
465 | /* |
466 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of | |
467 | * bytes. For each iovec, fault in each page that constitutes the iovec. | |
468 | * | |
469 | * Return 0 on success, or non-zero if the memory could not be accessed (i.e. | |
470 | * because it is an invalid address). | |
471 | */ | |
d4690f1e | 472 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) |
171a0203 AA |
473 | { |
474 | size_t skip = i->iov_offset; | |
475 | const struct iovec *iov; | |
476 | int err; | |
477 | struct iovec v; | |
478 | ||
479 | if (!(i->type & (ITER_BVEC|ITER_KVEC))) { | |
480 | iterate_iovec(i, bytes, v, iov, skip, ({ | |
4bce9f6e | 481 | err = fault_in_pages_readable(v.iov_base, v.iov_len); |
171a0203 AA |
482 | if (unlikely(err)) |
483 | return err; | |
484 | 0;})) | |
485 | } | |
486 | return 0; | |
487 | } | |
d4690f1e | 488 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
171a0203 | 489 | |
aa563d7b | 490 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
491 | const struct iovec *iov, unsigned long nr_segs, |
492 | size_t count) | |
493 | { | |
aa563d7b DH |
494 | WARN_ON(direction & ~(READ | WRITE)); |
495 | direction &= READ | WRITE; | |
496 | ||
71d8e532 | 497 | /* It will get better. Eventually... */ |
db68ce10 | 498 | if (uaccess_kernel()) { |
aa563d7b | 499 | i->type = ITER_KVEC | direction; |
a280455f AV |
500 | i->kvec = (struct kvec *)iov; |
501 | } else { | |
aa563d7b | 502 | i->type = ITER_IOVEC | direction; |
a280455f AV |
503 | i->iov = iov; |
504 | } | |
71d8e532 AV |
505 | i->nr_segs = nr_segs; |
506 | i->iov_offset = 0; | |
507 | i->count = count; | |
508 | } | |
509 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 510 | |
241699cd AV |
511 | static inline bool allocated(struct pipe_buffer *buf) |
512 | { | |
513 | return buf->ops == &default_pipe_buf_ops; | |
514 | } | |
515 | ||
8cefc107 DH |
516 | static inline void data_start(const struct iov_iter *i, |
517 | unsigned int *iter_headp, size_t *offp) | |
241699cd | 518 | { |
8cefc107 DH |
519 | unsigned int p_mask = i->pipe->ring_size - 1; |
520 | unsigned int iter_head = i->head; | |
241699cd | 521 | size_t off = i->iov_offset; |
8cefc107 DH |
522 | |
523 | if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || | |
524 | off == PAGE_SIZE)) { | |
525 | iter_head++; | |
241699cd AV |
526 | off = 0; |
527 | } | |
8cefc107 | 528 | *iter_headp = iter_head; |
241699cd AV |
529 | *offp = off; |
530 | } | |
531 | ||
532 | static size_t push_pipe(struct iov_iter *i, size_t size, | |
8cefc107 | 533 | int *iter_headp, size_t *offp) |
241699cd AV |
534 | { |
535 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
536 | unsigned int p_tail = pipe->tail; |
537 | unsigned int p_mask = pipe->ring_size - 1; | |
538 | unsigned int iter_head; | |
241699cd | 539 | size_t off; |
241699cd AV |
540 | ssize_t left; |
541 | ||
542 | if (unlikely(size > i->count)) | |
543 | size = i->count; | |
544 | if (unlikely(!size)) | |
545 | return 0; | |
546 | ||
547 | left = size; | |
8cefc107 DH |
548 | data_start(i, &iter_head, &off); |
549 | *iter_headp = iter_head; | |
241699cd AV |
550 | *offp = off; |
551 | if (off) { | |
552 | left -= PAGE_SIZE - off; | |
553 | if (left <= 0) { | |
8cefc107 | 554 | pipe->bufs[iter_head & p_mask].len += size; |
241699cd AV |
555 | return size; |
556 | } | |
8cefc107 DH |
557 | pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; |
558 | iter_head++; | |
241699cd | 559 | } |
6718b6f8 | 560 | while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { |
8cefc107 | 561 | struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; |
241699cd AV |
562 | struct page *page = alloc_page(GFP_USER); |
563 | if (!page) | |
564 | break; | |
8cefc107 DH |
565 | |
566 | buf->ops = &default_pipe_buf_ops; | |
567 | buf->page = page; | |
568 | buf->offset = 0; | |
569 | buf->len = min_t(ssize_t, left, PAGE_SIZE); | |
570 | left -= buf->len; | |
571 | iter_head++; | |
572 | pipe->head = iter_head; | |
573 | ||
574 | if (left == 0) | |
241699cd | 575 | return size; |
241699cd AV |
576 | } |
577 | return size - left; | |
578 | } | |
579 | ||
580 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, | |
581 | struct iov_iter *i) | |
582 | { | |
583 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
584 | unsigned int p_mask = pipe->ring_size - 1; |
585 | unsigned int i_head; | |
241699cd | 586 | size_t n, off; |
241699cd AV |
587 | |
588 | if (!sanity(i)) | |
589 | return 0; | |
590 | ||
8cefc107 | 591 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
592 | if (unlikely(!n)) |
593 | return 0; | |
8cefc107 | 594 | do { |
241699cd | 595 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
596 | memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); |
597 | i->head = i_head; | |
241699cd AV |
598 | i->iov_offset = off + chunk; |
599 | n -= chunk; | |
600 | addr += chunk; | |
8cefc107 DH |
601 | off = 0; |
602 | i_head++; | |
603 | } while (n); | |
241699cd AV |
604 | i->count -= bytes; |
605 | return bytes; | |
606 | } | |
607 | ||
f9152895 AV |
608 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
609 | __wsum sum, size_t off) | |
610 | { | |
cc44c17b | 611 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
f9152895 AV |
612 | return csum_block_add(sum, next, off); |
613 | } | |
614 | ||
78e1f386 | 615 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
52cbd23a WB |
616 | struct csum_state *csstate, |
617 | struct iov_iter *i) | |
78e1f386 AV |
618 | { |
619 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 | 620 | unsigned int p_mask = pipe->ring_size - 1; |
52cbd23a WB |
621 | __wsum sum = csstate->csum; |
622 | size_t off = csstate->off; | |
8cefc107 | 623 | unsigned int i_head; |
78e1f386 | 624 | size_t n, r; |
78e1f386 AV |
625 | |
626 | if (!sanity(i)) | |
627 | return 0; | |
628 | ||
8cefc107 | 629 | bytes = n = push_pipe(i, bytes, &i_head, &r); |
78e1f386 AV |
630 | if (unlikely(!n)) |
631 | return 0; | |
8cefc107 | 632 | do { |
78e1f386 | 633 | size_t chunk = min_t(size_t, n, PAGE_SIZE - r); |
8cefc107 | 634 | char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); |
f9152895 | 635 | sum = csum_and_memcpy(p + r, addr, chunk, sum, off); |
78e1f386 | 636 | kunmap_atomic(p); |
8cefc107 | 637 | i->head = i_head; |
78e1f386 AV |
638 | i->iov_offset = r + chunk; |
639 | n -= chunk; | |
640 | off += chunk; | |
641 | addr += chunk; | |
8cefc107 DH |
642 | r = 0; |
643 | i_head++; | |
644 | } while (n); | |
78e1f386 | 645 | i->count -= bytes; |
52cbd23a WB |
646 | csstate->csum = sum; |
647 | csstate->off = off; | |
78e1f386 AV |
648 | return bytes; |
649 | } | |
650 | ||
aa28de27 | 651 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 652 | { |
36f7a8a4 | 653 | const char *from = addr; |
00e23707 | 654 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 655 | return copy_pipe_to_iter(addr, bytes, i); |
09fc68dc AV |
656 | if (iter_is_iovec(i)) |
657 | might_fault(); | |
3d4d3e48 | 658 | iterate_and_advance(i, bytes, v, |
09fc68dc | 659 | copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
3d4d3e48 | 660 | memcpy_to_page(v.bv_page, v.bv_offset, |
a280455f | 661 | (from += v.bv_len) - v.bv_len, v.bv_len), |
7ff50620 DH |
662 | memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
663 | memcpy_to_page(v.bv_page, v.bv_offset, | |
664 | (from += v.bv_len) - v.bv_len, v.bv_len) | |
3d4d3e48 | 665 | ) |
62a8067a | 666 | |
3d4d3e48 | 667 | return bytes; |
c35e0248 | 668 | } |
aa28de27 | 669 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 670 | |
ec6347bb DW |
671 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
672 | static int copyout_mc(void __user *to, const void *from, size_t n) | |
8780356e | 673 | { |
96d4f267 | 674 | if (access_ok(to, n)) { |
d0ef4c36 | 675 | instrument_copy_to_user(to, from, n); |
ec6347bb | 676 | n = copy_mc_to_user((__force void *) to, from, n); |
8780356e DW |
677 | } |
678 | return n; | |
679 | } | |
680 | ||
ec6347bb | 681 | static unsigned long copy_mc_to_page(struct page *page, size_t offset, |
8780356e DW |
682 | const char *from, size_t len) |
683 | { | |
684 | unsigned long ret; | |
685 | char *to; | |
686 | ||
687 | to = kmap_atomic(page); | |
ec6347bb | 688 | ret = copy_mc_to_kernel(to + offset, from, len); |
8780356e DW |
689 | kunmap_atomic(to); |
690 | ||
691 | return ret; | |
692 | } | |
693 | ||
ec6347bb | 694 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
ca146f6f DW |
695 | struct iov_iter *i) |
696 | { | |
697 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
698 | unsigned int p_mask = pipe->ring_size - 1; |
699 | unsigned int i_head; | |
ca146f6f | 700 | size_t n, off, xfer = 0; |
ca146f6f DW |
701 | |
702 | if (!sanity(i)) | |
703 | return 0; | |
704 | ||
8cefc107 | 705 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
ca146f6f DW |
706 | if (unlikely(!n)) |
707 | return 0; | |
8cefc107 | 708 | do { |
ca146f6f DW |
709 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
710 | unsigned long rem; | |
711 | ||
ec6347bb | 712 | rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, |
8cefc107 DH |
713 | off, addr, chunk); |
714 | i->head = i_head; | |
ca146f6f DW |
715 | i->iov_offset = off + chunk - rem; |
716 | xfer += chunk - rem; | |
717 | if (rem) | |
718 | break; | |
719 | n -= chunk; | |
720 | addr += chunk; | |
8cefc107 DH |
721 | off = 0; |
722 | i_head++; | |
723 | } while (n); | |
ca146f6f DW |
724 | i->count -= xfer; |
725 | return xfer; | |
726 | } | |
727 | ||
bf3eeb9b | 728 | /** |
ec6347bb | 729 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
bf3eeb9b DW |
730 | * @addr: source kernel address |
731 | * @bytes: total transfer length | |
732 | * @iter: destination iterator | |
733 | * | |
ec6347bb DW |
734 | * The pmem driver deploys this for the dax operation |
735 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the | |
736 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes | |
737 | * successfully copied. | |
bf3eeb9b | 738 | * |
ec6347bb | 739 | * The main differences between this and typical _copy_to_iter(). |
bf3eeb9b DW |
740 | * |
741 | * * Typical tail/residue handling after a fault retries the copy | |
742 | * byte-by-byte until the fault happens again. Re-triggering machine | |
743 | * checks is potentially fatal so the implementation uses source | |
744 | * alignment and poison alignment assumptions to avoid re-triggering | |
745 | * hardware exceptions. | |
746 | * | |
747 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. | |
748 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return | |
749 | * a short copy. | |
bf3eeb9b | 750 | */ |
ec6347bb | 751 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
8780356e DW |
752 | { |
753 | const char *from = addr; | |
754 | unsigned long rem, curr_addr, s_addr = (unsigned long) addr; | |
755 | ||
00e23707 | 756 | if (unlikely(iov_iter_is_pipe(i))) |
ec6347bb | 757 | return copy_mc_pipe_to_iter(addr, bytes, i); |
8780356e DW |
758 | if (iter_is_iovec(i)) |
759 | might_fault(); | |
760 | iterate_and_advance(i, bytes, v, | |
ec6347bb DW |
761 | copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, |
762 | v.iov_len), | |
8780356e | 763 | ({ |
ec6347bb DW |
764 | rem = copy_mc_to_page(v.bv_page, v.bv_offset, |
765 | (from += v.bv_len) - v.bv_len, v.bv_len); | |
8780356e DW |
766 | if (rem) { |
767 | curr_addr = (unsigned long) from; | |
768 | bytes = curr_addr - s_addr - rem; | |
769 | return bytes; | |
770 | } | |
771 | }), | |
772 | ({ | |
ec6347bb DW |
773 | rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) |
774 | - v.iov_len, v.iov_len); | |
8780356e DW |
775 | if (rem) { |
776 | curr_addr = (unsigned long) from; | |
777 | bytes = curr_addr - s_addr - rem; | |
778 | return bytes; | |
779 | } | |
7ff50620 DH |
780 | }), |
781 | ({ | |
782 | rem = copy_mc_to_page(v.bv_page, v.bv_offset, | |
783 | (from += v.bv_len) - v.bv_len, v.bv_len); | |
784 | if (rem) { | |
785 | curr_addr = (unsigned long) from; | |
786 | bytes = curr_addr - s_addr - rem; | |
787 | rcu_read_unlock(); | |
3d14ec1f DH |
788 | i->iov_offset += bytes; |
789 | i->count -= bytes; | |
7ff50620 DH |
790 | return bytes; |
791 | } | |
8780356e DW |
792 | }) |
793 | ) | |
794 | ||
795 | return bytes; | |
796 | } | |
ec6347bb DW |
797 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
798 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ | |
8780356e | 799 | |
aa28de27 | 800 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 801 | { |
0dbca9a4 | 802 | char *to = addr; |
00e23707 | 803 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
804 | WARN_ON(1); |
805 | return 0; | |
806 | } | |
09fc68dc AV |
807 | if (iter_is_iovec(i)) |
808 | might_fault(); | |
0dbca9a4 | 809 | iterate_and_advance(i, bytes, v, |
09fc68dc | 810 | copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
0dbca9a4 | 811 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 812 | v.bv_offset, v.bv_len), |
7ff50620 DH |
813 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
814 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
815 | v.bv_offset, v.bv_len) | |
0dbca9a4 AV |
816 | ) |
817 | ||
818 | return bytes; | |
c35e0248 | 819 | } |
aa28de27 | 820 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 821 | |
aa28de27 | 822 | bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) |
cbbd26b8 AV |
823 | { |
824 | char *to = addr; | |
00e23707 | 825 | if (unlikely(iov_iter_is_pipe(i))) { |
cbbd26b8 AV |
826 | WARN_ON(1); |
827 | return false; | |
828 | } | |
33844e66 | 829 | if (unlikely(i->count < bytes)) |
cbbd26b8 AV |
830 | return false; |
831 | ||
09fc68dc AV |
832 | if (iter_is_iovec(i)) |
833 | might_fault(); | |
cbbd26b8 | 834 | iterate_all_kinds(i, bytes, v, ({ |
09fc68dc | 835 | if (copyin((to += v.iov_len) - v.iov_len, |
cbbd26b8 AV |
836 | v.iov_base, v.iov_len)) |
837 | return false; | |
838 | 0;}), | |
839 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
840 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
841 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
842 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
843 | v.bv_offset, v.bv_len) | |
cbbd26b8 AV |
844 | ) |
845 | ||
846 | iov_iter_advance(i, bytes); | |
847 | return true; | |
848 | } | |
aa28de27 | 849 | EXPORT_SYMBOL(_copy_from_iter_full); |
cbbd26b8 | 850 | |
aa28de27 | 851 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 AV |
852 | { |
853 | char *to = addr; | |
00e23707 | 854 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
855 | WARN_ON(1); |
856 | return 0; | |
857 | } | |
aa583096 | 858 | iterate_and_advance(i, bytes, v, |
3f763453 | 859 | __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
aa583096 AV |
860 | v.iov_base, v.iov_len), |
861 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
862 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
863 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
864 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
865 | v.bv_offset, v.bv_len) | |
aa583096 AV |
866 | ) |
867 | ||
868 | return bytes; | |
869 | } | |
aa28de27 | 870 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 871 | |
0aed55af | 872 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
873 | /** |
874 | * _copy_from_iter_flushcache - write destination through cpu cache | |
875 | * @addr: destination kernel address | |
876 | * @bytes: total transfer length | |
877 | * @iter: source iterator | |
878 | * | |
879 | * The pmem driver arranges for filesystem-dax to use this facility via | |
880 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
881 | * are flushed through the CPU cache. It is differentiated from | |
882 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
883 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
884 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
885 | * instructions that strand dirty-data in the cache. | |
886 | */ | |
6a37e940 | 887 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af DW |
888 | { |
889 | char *to = addr; | |
00e23707 | 890 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
891 | WARN_ON(1); |
892 | return 0; | |
893 | } | |
894 | iterate_and_advance(i, bytes, v, | |
895 | __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, | |
896 | v.iov_base, v.iov_len), | |
897 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
898 | v.bv_offset, v.bv_len), | |
899 | memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, | |
7ff50620 DH |
900 | v.iov_len), |
901 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
902 | v.bv_offset, v.bv_len) | |
0aed55af DW |
903 | ) |
904 | ||
905 | return bytes; | |
906 | } | |
6a37e940 | 907 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
908 | #endif |
909 | ||
aa28de27 | 910 | bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) |
cbbd26b8 AV |
911 | { |
912 | char *to = addr; | |
00e23707 | 913 | if (unlikely(iov_iter_is_pipe(i))) { |
cbbd26b8 AV |
914 | WARN_ON(1); |
915 | return false; | |
916 | } | |
33844e66 | 917 | if (unlikely(i->count < bytes)) |
cbbd26b8 AV |
918 | return false; |
919 | iterate_all_kinds(i, bytes, v, ({ | |
3f763453 | 920 | if (__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
cbbd26b8 AV |
921 | v.iov_base, v.iov_len)) |
922 | return false; | |
923 | 0;}), | |
924 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
925 | v.bv_offset, v.bv_len), | |
7ff50620 DH |
926 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
927 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
928 | v.bv_offset, v.bv_len) | |
cbbd26b8 AV |
929 | ) |
930 | ||
931 | iov_iter_advance(i, bytes); | |
932 | return true; | |
933 | } | |
aa28de27 | 934 | EXPORT_SYMBOL(_copy_from_iter_full_nocache); |
cbbd26b8 | 935 | |
72e809ed AV |
936 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
937 | { | |
6daef95b ED |
938 | struct page *head; |
939 | size_t v = n + offset; | |
940 | ||
941 | /* | |
942 | * The general case needs to access the page order in order | |
943 | * to compute the page size. | |
944 | * However, we mostly deal with order-0 pages and thus can | |
945 | * avoid a possible cache line miss for requests that fit all | |
946 | * page orders. | |
947 | */ | |
948 | if (n <= v && v <= PAGE_SIZE) | |
949 | return true; | |
950 | ||
951 | head = compound_head(page); | |
952 | v += (page - head) << PAGE_SHIFT; | |
a90bcb86 | 953 | |
a50b854e | 954 | if (likely(n <= v && v <= (page_size(head)))) |
72e809ed AV |
955 | return true; |
956 | WARN_ON(1); | |
957 | return false; | |
958 | } | |
cbbd26b8 | 959 | |
62a8067a AV |
960 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
961 | struct iov_iter *i) | |
962 | { | |
72e809ed AV |
963 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
964 | return 0; | |
7ff50620 | 965 | if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { |
d271524a AV |
966 | void *kaddr = kmap_atomic(page); |
967 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); | |
968 | kunmap_atomic(kaddr); | |
969 | return wanted; | |
9ea9ce04 DH |
970 | } else if (unlikely(iov_iter_is_discard(i))) |
971 | return bytes; | |
972 | else if (likely(!iov_iter_is_pipe(i))) | |
62a8067a | 973 | return copy_page_to_iter_iovec(page, offset, bytes, i); |
241699cd AV |
974 | else |
975 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
62a8067a AV |
976 | } |
977 | EXPORT_SYMBOL(copy_page_to_iter); | |
978 | ||
979 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
980 | struct iov_iter *i) | |
981 | { | |
72e809ed AV |
982 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
983 | return 0; | |
9ea9ce04 | 984 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
985 | WARN_ON(1); |
986 | return 0; | |
987 | } | |
7ff50620 | 988 | if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { |
d271524a | 989 | void *kaddr = kmap_atomic(page); |
aa28de27 | 990 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
d271524a AV |
991 | kunmap_atomic(kaddr); |
992 | return wanted; | |
993 | } else | |
62a8067a AV |
994 | return copy_page_from_iter_iovec(page, offset, bytes, i); |
995 | } | |
996 | EXPORT_SYMBOL(copy_page_from_iter); | |
997 | ||
241699cd AV |
998 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
999 | { | |
1000 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1001 | unsigned int p_mask = pipe->ring_size - 1; |
1002 | unsigned int i_head; | |
241699cd | 1003 | size_t n, off; |
241699cd AV |
1004 | |
1005 | if (!sanity(i)) | |
1006 | return 0; | |
1007 | ||
8cefc107 | 1008 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
241699cd AV |
1009 | if (unlikely(!n)) |
1010 | return 0; | |
1011 | ||
8cefc107 | 1012 | do { |
241699cd | 1013 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
8cefc107 DH |
1014 | memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); |
1015 | i->head = i_head; | |
241699cd AV |
1016 | i->iov_offset = off + chunk; |
1017 | n -= chunk; | |
8cefc107 DH |
1018 | off = 0; |
1019 | i_head++; | |
1020 | } while (n); | |
241699cd AV |
1021 | i->count -= bytes; |
1022 | return bytes; | |
1023 | } | |
1024 | ||
c35e0248 MW |
1025 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
1026 | { | |
00e23707 | 1027 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1028 | return pipe_zero(bytes, i); |
8442fa46 | 1029 | iterate_and_advance(i, bytes, v, |
09fc68dc | 1030 | clear_user(v.iov_base, v.iov_len), |
a280455f | 1031 | memzero_page(v.bv_page, v.bv_offset, v.bv_len), |
7ff50620 DH |
1032 | memset(v.iov_base, 0, v.iov_len), |
1033 | memzero_page(v.bv_page, v.bv_offset, v.bv_len) | |
8442fa46 AV |
1034 | ) |
1035 | ||
1036 | return bytes; | |
c35e0248 MW |
1037 | } |
1038 | EXPORT_SYMBOL(iov_iter_zero); | |
1039 | ||
62a8067a AV |
1040 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
1041 | struct iov_iter *i, unsigned long offset, size_t bytes) | |
1042 | { | |
04a31165 | 1043 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
1044 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
1045 | kunmap_atomic(kaddr); | |
1046 | return 0; | |
1047 | } | |
9ea9ce04 | 1048 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1049 | kunmap_atomic(kaddr); |
1050 | WARN_ON(1); | |
1051 | return 0; | |
1052 | } | |
04a31165 | 1053 | iterate_all_kinds(i, bytes, v, |
09fc68dc | 1054 | copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
04a31165 | 1055 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, |
a280455f | 1056 | v.bv_offset, v.bv_len), |
7ff50620 DH |
1057 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
1058 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, | |
1059 | v.bv_offset, v.bv_len) | |
04a31165 AV |
1060 | ) |
1061 | kunmap_atomic(kaddr); | |
1062 | return bytes; | |
62a8067a AV |
1063 | } |
1064 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); | |
1065 | ||
b9dc6f65 AV |
1066 | static inline void pipe_truncate(struct iov_iter *i) |
1067 | { | |
1068 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1069 | unsigned int p_tail = pipe->tail; |
1070 | unsigned int p_head = pipe->head; | |
1071 | unsigned int p_mask = pipe->ring_size - 1; | |
1072 | ||
1073 | if (!pipe_empty(p_head, p_tail)) { | |
1074 | struct pipe_buffer *buf; | |
1075 | unsigned int i_head = i->head; | |
b9dc6f65 | 1076 | size_t off = i->iov_offset; |
8cefc107 | 1077 | |
b9dc6f65 | 1078 | if (off) { |
8cefc107 DH |
1079 | buf = &pipe->bufs[i_head & p_mask]; |
1080 | buf->len = off - buf->offset; | |
1081 | i_head++; | |
b9dc6f65 | 1082 | } |
8cefc107 DH |
1083 | while (p_head != i_head) { |
1084 | p_head--; | |
1085 | pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); | |
b9dc6f65 | 1086 | } |
8cefc107 DH |
1087 | |
1088 | pipe->head = p_head; | |
b9dc6f65 AV |
1089 | } |
1090 | } | |
1091 | ||
241699cd AV |
1092 | static void pipe_advance(struct iov_iter *i, size_t size) |
1093 | { | |
1094 | struct pipe_inode_info *pipe = i->pipe; | |
241699cd AV |
1095 | if (unlikely(i->count < size)) |
1096 | size = i->count; | |
241699cd | 1097 | if (size) { |
b9dc6f65 | 1098 | struct pipe_buffer *buf; |
8cefc107 DH |
1099 | unsigned int p_mask = pipe->ring_size - 1; |
1100 | unsigned int i_head = i->head; | |
b9dc6f65 | 1101 | size_t off = i->iov_offset, left = size; |
8cefc107 | 1102 | |
241699cd | 1103 | if (off) /* make it relative to the beginning of buffer */ |
8cefc107 | 1104 | left += off - pipe->bufs[i_head & p_mask].offset; |
241699cd | 1105 | while (1) { |
8cefc107 | 1106 | buf = &pipe->bufs[i_head & p_mask]; |
b9dc6f65 | 1107 | if (left <= buf->len) |
241699cd | 1108 | break; |
b9dc6f65 | 1109 | left -= buf->len; |
8cefc107 | 1110 | i_head++; |
241699cd | 1111 | } |
8cefc107 | 1112 | i->head = i_head; |
b9dc6f65 | 1113 | i->iov_offset = buf->offset + left; |
241699cd | 1114 | } |
b9dc6f65 AV |
1115 | i->count -= size; |
1116 | /* ... and discard everything past that point */ | |
1117 | pipe_truncate(i); | |
241699cd AV |
1118 | } |
1119 | ||
54c8195b PB |
1120 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
1121 | { | |
1122 | struct bvec_iter bi; | |
1123 | ||
1124 | bi.bi_size = i->count; | |
1125 | bi.bi_bvec_done = i->iov_offset; | |
1126 | bi.bi_idx = 0; | |
1127 | bvec_iter_advance(i->bvec, &bi, size); | |
1128 | ||
1129 | i->bvec += bi.bi_idx; | |
1130 | i->nr_segs -= bi.bi_idx; | |
1131 | i->count = bi.bi_size; | |
1132 | i->iov_offset = bi.bi_bvec_done; | |
1133 | } | |
1134 | ||
62a8067a AV |
1135 | void iov_iter_advance(struct iov_iter *i, size_t size) |
1136 | { | |
00e23707 | 1137 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
1138 | pipe_advance(i, size); |
1139 | return; | |
1140 | } | |
9ea9ce04 DH |
1141 | if (unlikely(iov_iter_is_discard(i))) { |
1142 | i->count -= size; | |
1143 | return; | |
1144 | } | |
7ff50620 | 1145 | if (unlikely(iov_iter_is_xarray(i))) { |
3d14ec1f | 1146 | size = min(size, i->count); |
7ff50620 DH |
1147 | i->iov_offset += size; |
1148 | i->count -= size; | |
1149 | return; | |
1150 | } | |
54c8195b PB |
1151 | if (iov_iter_is_bvec(i)) { |
1152 | iov_iter_bvec_advance(i, size); | |
1153 | return; | |
1154 | } | |
7ff50620 | 1155 | iterate_and_advance(i, size, v, 0, 0, 0, 0) |
62a8067a AV |
1156 | } |
1157 | EXPORT_SYMBOL(iov_iter_advance); | |
1158 | ||
27c0e374 AV |
1159 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
1160 | { | |
1161 | if (!unroll) | |
1162 | return; | |
5b47d59a AV |
1163 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
1164 | return; | |
27c0e374 | 1165 | i->count += unroll; |
00e23707 | 1166 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 | 1167 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 DH |
1168 | unsigned int p_mask = pipe->ring_size - 1; |
1169 | unsigned int i_head = i->head; | |
27c0e374 AV |
1170 | size_t off = i->iov_offset; |
1171 | while (1) { | |
8cefc107 DH |
1172 | struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; |
1173 | size_t n = off - b->offset; | |
27c0e374 | 1174 | if (unroll < n) { |
4fa55cef | 1175 | off -= unroll; |
27c0e374 AV |
1176 | break; |
1177 | } | |
1178 | unroll -= n; | |
8cefc107 | 1179 | if (!unroll && i_head == i->start_head) { |
27c0e374 AV |
1180 | off = 0; |
1181 | break; | |
1182 | } | |
8cefc107 DH |
1183 | i_head--; |
1184 | b = &pipe->bufs[i_head & p_mask]; | |
1185 | off = b->offset + b->len; | |
27c0e374 AV |
1186 | } |
1187 | i->iov_offset = off; | |
8cefc107 | 1188 | i->head = i_head; |
27c0e374 AV |
1189 | pipe_truncate(i); |
1190 | return; | |
1191 | } | |
9ea9ce04 DH |
1192 | if (unlikely(iov_iter_is_discard(i))) |
1193 | return; | |
27c0e374 AV |
1194 | if (unroll <= i->iov_offset) { |
1195 | i->iov_offset -= unroll; | |
1196 | return; | |
1197 | } | |
1198 | unroll -= i->iov_offset; | |
7ff50620 DH |
1199 | if (iov_iter_is_xarray(i)) { |
1200 | BUG(); /* We should never go beyond the start of the specified | |
1201 | * range since we might then be straying into pages that | |
1202 | * aren't pinned. | |
1203 | */ | |
1204 | } else if (iov_iter_is_bvec(i)) { | |
27c0e374 AV |
1205 | const struct bio_vec *bvec = i->bvec; |
1206 | while (1) { | |
1207 | size_t n = (--bvec)->bv_len; | |
1208 | i->nr_segs++; | |
1209 | if (unroll <= n) { | |
1210 | i->bvec = bvec; | |
1211 | i->iov_offset = n - unroll; | |
1212 | return; | |
1213 | } | |
1214 | unroll -= n; | |
1215 | } | |
1216 | } else { /* same logics for iovec and kvec */ | |
1217 | const struct iovec *iov = i->iov; | |
1218 | while (1) { | |
1219 | size_t n = (--iov)->iov_len; | |
1220 | i->nr_segs++; | |
1221 | if (unroll <= n) { | |
1222 | i->iov = iov; | |
1223 | i->iov_offset = n - unroll; | |
1224 | return; | |
1225 | } | |
1226 | unroll -= n; | |
1227 | } | |
1228 | } | |
1229 | } | |
1230 | EXPORT_SYMBOL(iov_iter_revert); | |
1231 | ||
62a8067a AV |
1232 | /* |
1233 | * Return the count of just the current iov_iter segment. | |
1234 | */ | |
1235 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
1236 | { | |
00e23707 | 1237 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1238 | return i->count; // it is a silly place, anyway |
62a8067a AV |
1239 | if (i->nr_segs == 1) |
1240 | return i->count; | |
7ff50620 | 1241 | if (unlikely(iov_iter_is_discard(i) || iov_iter_is_xarray(i))) |
9ea9ce04 | 1242 | return i->count; |
7ff50620 | 1243 | if (iov_iter_is_bvec(i)) |
62a8067a | 1244 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
ad0eab92 PM |
1245 | else |
1246 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
62a8067a AV |
1247 | } |
1248 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
1249 | ||
aa563d7b | 1250 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 1251 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
1252 | size_t count) |
1253 | { | |
aa563d7b DH |
1254 | WARN_ON(direction & ~(READ | WRITE)); |
1255 | i->type = ITER_KVEC | (direction & (READ | WRITE)); | |
05afcb77 | 1256 | i->kvec = kvec; |
abb78f87 AV |
1257 | i->nr_segs = nr_segs; |
1258 | i->iov_offset = 0; | |
1259 | i->count = count; | |
1260 | } | |
1261 | EXPORT_SYMBOL(iov_iter_kvec); | |
1262 | ||
aa563d7b | 1263 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1264 | const struct bio_vec *bvec, unsigned long nr_segs, |
1265 | size_t count) | |
1266 | { | |
aa563d7b DH |
1267 | WARN_ON(direction & ~(READ | WRITE)); |
1268 | i->type = ITER_BVEC | (direction & (READ | WRITE)); | |
05afcb77 AV |
1269 | i->bvec = bvec; |
1270 | i->nr_segs = nr_segs; | |
1271 | i->iov_offset = 0; | |
1272 | i->count = count; | |
1273 | } | |
1274 | EXPORT_SYMBOL(iov_iter_bvec); | |
1275 | ||
aa563d7b | 1276 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1277 | struct pipe_inode_info *pipe, |
1278 | size_t count) | |
1279 | { | |
aa563d7b | 1280 | BUG_ON(direction != READ); |
8cefc107 | 1281 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
aa563d7b | 1282 | i->type = ITER_PIPE | READ; |
241699cd | 1283 | i->pipe = pipe; |
8cefc107 | 1284 | i->head = pipe->head; |
241699cd AV |
1285 | i->iov_offset = 0; |
1286 | i->count = count; | |
8cefc107 | 1287 | i->start_head = i->head; |
241699cd AV |
1288 | } |
1289 | EXPORT_SYMBOL(iov_iter_pipe); | |
1290 | ||
7ff50620 DH |
1291 | /** |
1292 | * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray | |
1293 | * @i: The iterator to initialise. | |
1294 | * @direction: The direction of the transfer. | |
1295 | * @xarray: The xarray to access. | |
1296 | * @start: The start file position. | |
1297 | * @count: The size of the I/O buffer in bytes. | |
1298 | * | |
1299 | * Set up an I/O iterator to either draw data out of the pages attached to an | |
1300 | * inode or to inject data into those pages. The pages *must* be prevented | |
1301 | * from evaporation, either by taking a ref on them or locking them by the | |
1302 | * caller. | |
1303 | */ | |
1304 | void iov_iter_xarray(struct iov_iter *i, unsigned int direction, | |
1305 | struct xarray *xarray, loff_t start, size_t count) | |
1306 | { | |
1307 | BUG_ON(direction & ~1); | |
1308 | i->type = ITER_XARRAY | (direction & (READ | WRITE)); | |
1309 | i->xarray = xarray; | |
1310 | i->xarray_start = start; | |
1311 | i->count = count; | |
1312 | i->iov_offset = 0; | |
1313 | } | |
1314 | EXPORT_SYMBOL(iov_iter_xarray); | |
1315 | ||
9ea9ce04 DH |
1316 | /** |
1317 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
1318 | * @i: The iterator to initialise. | |
1319 | * @direction: The direction of the transfer. | |
1320 | * @count: The size of the I/O buffer in bytes. | |
1321 | * | |
1322 | * Set up an I/O iterator that just discards everything that's written to it. | |
1323 | * It's only available as a READ iterator. | |
1324 | */ | |
1325 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
1326 | { | |
1327 | BUG_ON(direction != READ); | |
1328 | i->type = ITER_DISCARD | READ; | |
1329 | i->count = count; | |
1330 | i->iov_offset = 0; | |
1331 | } | |
1332 | EXPORT_SYMBOL(iov_iter_discard); | |
1333 | ||
62a8067a AV |
1334 | unsigned long iov_iter_alignment(const struct iov_iter *i) |
1335 | { | |
04a31165 AV |
1336 | unsigned long res = 0; |
1337 | size_t size = i->count; | |
1338 | ||
00e23707 | 1339 | if (unlikely(iov_iter_is_pipe(i))) { |
e0ff126e JK |
1340 | unsigned int p_mask = i->pipe->ring_size - 1; |
1341 | ||
8cefc107 | 1342 | if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) |
241699cd AV |
1343 | return size | i->iov_offset; |
1344 | return size; | |
1345 | } | |
3d14ec1f DH |
1346 | if (unlikely(iov_iter_is_xarray(i))) |
1347 | return (i->xarray_start + i->iov_offset) | i->count; | |
04a31165 AV |
1348 | iterate_all_kinds(i, size, v, |
1349 | (res |= (unsigned long)v.iov_base | v.iov_len, 0), | |
a280455f | 1350 | res |= v.bv_offset | v.bv_len, |
7ff50620 DH |
1351 | res |= (unsigned long)v.iov_base | v.iov_len, |
1352 | res |= v.bv_offset | v.bv_len | |
04a31165 AV |
1353 | ) |
1354 | return res; | |
62a8067a AV |
1355 | } |
1356 | EXPORT_SYMBOL(iov_iter_alignment); | |
1357 | ||
357f435d AV |
1358 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1359 | { | |
33844e66 | 1360 | unsigned long res = 0; |
357f435d | 1361 | size_t size = i->count; |
357f435d | 1362 | |
9ea9ce04 | 1363 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1364 | WARN_ON(1); |
1365 | return ~0U; | |
1366 | } | |
1367 | ||
357f435d AV |
1368 | iterate_all_kinds(i, size, v, |
1369 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | | |
1370 | (size != v.iov_len ? size : 0), 0), | |
1371 | (res |= (!res ? 0 : (unsigned long)v.bv_offset) | | |
1372 | (size != v.bv_len ? size : 0)), | |
1373 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | | |
7ff50620 DH |
1374 | (size != v.iov_len ? size : 0)), |
1375 | (res |= (!res ? 0 : (unsigned long)v.bv_offset) | | |
1376 | (size != v.bv_len ? size : 0)) | |
357f435d | 1377 | ); |
33844e66 | 1378 | return res; |
357f435d AV |
1379 | } |
1380 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1381 | ||
e76b6312 | 1382 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
241699cd AV |
1383 | size_t maxsize, |
1384 | struct page **pages, | |
8cefc107 | 1385 | int iter_head, |
241699cd AV |
1386 | size_t *start) |
1387 | { | |
1388 | struct pipe_inode_info *pipe = i->pipe; | |
8cefc107 DH |
1389 | unsigned int p_mask = pipe->ring_size - 1; |
1390 | ssize_t n = push_pipe(i, maxsize, &iter_head, start); | |
241699cd AV |
1391 | if (!n) |
1392 | return -EFAULT; | |
1393 | ||
1394 | maxsize = n; | |
1395 | n += *start; | |
1689c73a | 1396 | while (n > 0) { |
8cefc107 DH |
1397 | get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); |
1398 | iter_head++; | |
241699cd AV |
1399 | n -= PAGE_SIZE; |
1400 | } | |
1401 | ||
1402 | return maxsize; | |
1403 | } | |
1404 | ||
1405 | static ssize_t pipe_get_pages(struct iov_iter *i, | |
1406 | struct page **pages, size_t maxsize, unsigned maxpages, | |
1407 | size_t *start) | |
1408 | { | |
8cefc107 | 1409 | unsigned int iter_head, npages; |
241699cd | 1410 | size_t capacity; |
241699cd | 1411 | |
33844e66 AV |
1412 | if (!maxsize) |
1413 | return 0; | |
1414 | ||
241699cd AV |
1415 | if (!sanity(i)) |
1416 | return -EFAULT; | |
1417 | ||
8cefc107 DH |
1418 | data_start(i, &iter_head, start); |
1419 | /* Amount of free space: some of this one + all after this one */ | |
1420 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
1421 | capacity = min(npages, maxpages) * PAGE_SIZE - *start; | |
241699cd | 1422 | |
8cefc107 | 1423 | return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); |
241699cd AV |
1424 | } |
1425 | ||
7ff50620 DH |
1426 | static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, |
1427 | pgoff_t index, unsigned int nr_pages) | |
1428 | { | |
1429 | XA_STATE(xas, xa, index); | |
1430 | struct page *page; | |
1431 | unsigned int ret = 0; | |
1432 | ||
1433 | rcu_read_lock(); | |
1434 | for (page = xas_load(&xas); page; page = xas_next(&xas)) { | |
1435 | if (xas_retry(&xas, page)) | |
1436 | continue; | |
1437 | ||
1438 | /* Has the page moved or been split? */ | |
1439 | if (unlikely(page != xas_reload(&xas))) { | |
1440 | xas_reset(&xas); | |
1441 | continue; | |
1442 | } | |
1443 | ||
1444 | pages[ret] = find_subpage(page, xas.xa_index); | |
1445 | get_page(pages[ret]); | |
1446 | if (++ret == nr_pages) | |
1447 | break; | |
1448 | } | |
1449 | rcu_read_unlock(); | |
1450 | return ret; | |
1451 | } | |
1452 | ||
1453 | static ssize_t iter_xarray_get_pages(struct iov_iter *i, | |
1454 | struct page **pages, size_t maxsize, | |
1455 | unsigned maxpages, size_t *_start_offset) | |
1456 | { | |
1457 | unsigned nr, offset; | |
1458 | pgoff_t index, count; | |
1459 | size_t size = maxsize, actual; | |
1460 | loff_t pos; | |
1461 | ||
1462 | if (!size || !maxpages) | |
1463 | return 0; | |
1464 | ||
1465 | pos = i->xarray_start + i->iov_offset; | |
1466 | index = pos >> PAGE_SHIFT; | |
1467 | offset = pos & ~PAGE_MASK; | |
1468 | *_start_offset = offset; | |
1469 | ||
1470 | count = 1; | |
1471 | if (size > PAGE_SIZE - offset) { | |
1472 | size -= PAGE_SIZE - offset; | |
1473 | count += size >> PAGE_SHIFT; | |
1474 | size &= ~PAGE_MASK; | |
1475 | if (size) | |
1476 | count++; | |
1477 | } | |
1478 | ||
1479 | if (count > maxpages) | |
1480 | count = maxpages; | |
1481 | ||
1482 | nr = iter_xarray_populate_pages(pages, i->xarray, index, count); | |
1483 | if (nr == 0) | |
1484 | return 0; | |
1485 | ||
1486 | actual = PAGE_SIZE * nr; | |
1487 | actual -= offset; | |
1488 | if (nr == count && size > 0) { | |
1489 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1490 | actual -= PAGE_SIZE - (last_offset + size); | |
1491 | } | |
1492 | return actual; | |
1493 | } | |
1494 | ||
62a8067a | 1495 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
2c80929c | 1496 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
1497 | size_t *start) |
1498 | { | |
e5393fae AV |
1499 | if (maxsize > i->count) |
1500 | maxsize = i->count; | |
1501 | ||
00e23707 | 1502 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1503 | return pipe_get_pages(i, pages, maxsize, maxpages, start); |
7ff50620 DH |
1504 | if (unlikely(iov_iter_is_xarray(i))) |
1505 | return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); | |
9ea9ce04 DH |
1506 | if (unlikely(iov_iter_is_discard(i))) |
1507 | return -EFAULT; | |
1508 | ||
e5393fae AV |
1509 | iterate_all_kinds(i, maxsize, v, ({ |
1510 | unsigned long addr = (unsigned long)v.iov_base; | |
1511 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
1512 | int n; | |
1513 | int res; | |
1514 | ||
1515 | if (len > maxpages * PAGE_SIZE) | |
1516 | len = maxpages * PAGE_SIZE; | |
1517 | addr &= ~(PAGE_SIZE - 1); | |
1518 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
73b0140b IW |
1519 | res = get_user_pages_fast(addr, n, |
1520 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, | |
1521 | pages); | |
e5393fae AV |
1522 | if (unlikely(res < 0)) |
1523 | return res; | |
1524 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
1525 | 0;}),({ | |
1526 | /* can't be more than PAGE_SIZE */ | |
1527 | *start = v.bv_offset; | |
1528 | get_page(*pages = v.bv_page); | |
1529 | return v.bv_len; | |
a280455f AV |
1530 | }),({ |
1531 | return -EFAULT; | |
7ff50620 DH |
1532 | }), |
1533 | 0 | |
e5393fae AV |
1534 | ) |
1535 | return 0; | |
62a8067a AV |
1536 | } |
1537 | EXPORT_SYMBOL(iov_iter_get_pages); | |
1538 | ||
1b17f1f2 AV |
1539 | static struct page **get_pages_array(size_t n) |
1540 | { | |
752ade68 | 1541 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); |
1b17f1f2 AV |
1542 | } |
1543 | ||
241699cd AV |
1544 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
1545 | struct page ***pages, size_t maxsize, | |
1546 | size_t *start) | |
1547 | { | |
1548 | struct page **p; | |
8cefc107 | 1549 | unsigned int iter_head, npages; |
d7760d63 | 1550 | ssize_t n; |
241699cd | 1551 | |
33844e66 AV |
1552 | if (!maxsize) |
1553 | return 0; | |
1554 | ||
241699cd AV |
1555 | if (!sanity(i)) |
1556 | return -EFAULT; | |
1557 | ||
8cefc107 DH |
1558 | data_start(i, &iter_head, start); |
1559 | /* Amount of free space: some of this one + all after this one */ | |
1560 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); | |
241699cd AV |
1561 | n = npages * PAGE_SIZE - *start; |
1562 | if (maxsize > n) | |
1563 | maxsize = n; | |
1564 | else | |
1565 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); | |
1566 | p = get_pages_array(npages); | |
1567 | if (!p) | |
1568 | return -ENOMEM; | |
8cefc107 | 1569 | n = __pipe_get_pages(i, maxsize, p, iter_head, start); |
241699cd AV |
1570 | if (n > 0) |
1571 | *pages = p; | |
1572 | else | |
1573 | kvfree(p); | |
1574 | return n; | |
1575 | } | |
1576 | ||
7ff50620 DH |
1577 | static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, |
1578 | struct page ***pages, size_t maxsize, | |
1579 | size_t *_start_offset) | |
1580 | { | |
1581 | struct page **p; | |
1582 | unsigned nr, offset; | |
1583 | pgoff_t index, count; | |
1584 | size_t size = maxsize, actual; | |
1585 | loff_t pos; | |
1586 | ||
1587 | if (!size) | |
1588 | return 0; | |
1589 | ||
1590 | pos = i->xarray_start + i->iov_offset; | |
1591 | index = pos >> PAGE_SHIFT; | |
1592 | offset = pos & ~PAGE_MASK; | |
1593 | *_start_offset = offset; | |
1594 | ||
1595 | count = 1; | |
1596 | if (size > PAGE_SIZE - offset) { | |
1597 | size -= PAGE_SIZE - offset; | |
1598 | count += size >> PAGE_SHIFT; | |
1599 | size &= ~PAGE_MASK; | |
1600 | if (size) | |
1601 | count++; | |
1602 | } | |
1603 | ||
1604 | p = get_pages_array(count); | |
1605 | if (!p) | |
1606 | return -ENOMEM; | |
1607 | *pages = p; | |
1608 | ||
1609 | nr = iter_xarray_populate_pages(p, i->xarray, index, count); | |
1610 | if (nr == 0) | |
1611 | return 0; | |
1612 | ||
1613 | actual = PAGE_SIZE * nr; | |
1614 | actual -= offset; | |
1615 | if (nr == count && size > 0) { | |
1616 | unsigned last_offset = (nr > 1) ? 0 : offset; | |
1617 | actual -= PAGE_SIZE - (last_offset + size); | |
1618 | } | |
1619 | return actual; | |
1620 | } | |
1621 | ||
62a8067a AV |
1622 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
1623 | struct page ***pages, size_t maxsize, | |
1624 | size_t *start) | |
1625 | { | |
1b17f1f2 AV |
1626 | struct page **p; |
1627 | ||
1628 | if (maxsize > i->count) | |
1629 | maxsize = i->count; | |
1630 | ||
00e23707 | 1631 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1632 | return pipe_get_pages_alloc(i, pages, maxsize, start); |
7ff50620 DH |
1633 | if (unlikely(iov_iter_is_xarray(i))) |
1634 | return iter_xarray_get_pages_alloc(i, pages, maxsize, start); | |
9ea9ce04 DH |
1635 | if (unlikely(iov_iter_is_discard(i))) |
1636 | return -EFAULT; | |
1637 | ||
1b17f1f2 AV |
1638 | iterate_all_kinds(i, maxsize, v, ({ |
1639 | unsigned long addr = (unsigned long)v.iov_base; | |
1640 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
1641 | int n; | |
1642 | int res; | |
1643 | ||
1644 | addr &= ~(PAGE_SIZE - 1); | |
1645 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1646 | p = get_pages_array(n); | |
1647 | if (!p) | |
1648 | return -ENOMEM; | |
73b0140b IW |
1649 | res = get_user_pages_fast(addr, n, |
1650 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); | |
1b17f1f2 AV |
1651 | if (unlikely(res < 0)) { |
1652 | kvfree(p); | |
1653 | return res; | |
1654 | } | |
1655 | *pages = p; | |
1656 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
1657 | 0;}),({ | |
1658 | /* can't be more than PAGE_SIZE */ | |
1659 | *start = v.bv_offset; | |
1660 | *pages = p = get_pages_array(1); | |
1661 | if (!p) | |
1662 | return -ENOMEM; | |
1663 | get_page(*p = v.bv_page); | |
1664 | return v.bv_len; | |
a280455f AV |
1665 | }),({ |
1666 | return -EFAULT; | |
7ff50620 | 1667 | }), 0 |
1b17f1f2 AV |
1668 | ) |
1669 | return 0; | |
62a8067a AV |
1670 | } |
1671 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
1672 | ||
a604ec7e AV |
1673 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1674 | struct iov_iter *i) | |
1675 | { | |
1676 | char *to = addr; | |
1677 | __wsum sum, next; | |
1678 | size_t off = 0; | |
a604ec7e | 1679 | sum = *csum; |
9ea9ce04 | 1680 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1681 | WARN_ON(1); |
1682 | return 0; | |
1683 | } | |
a604ec7e | 1684 | iterate_and_advance(i, bytes, v, ({ |
cbbd26b8 | 1685 | next = csum_and_copy_from_user(v.iov_base, |
a604ec7e | 1686 | (to += v.iov_len) - v.iov_len, |
c693cc46 AV |
1687 | v.iov_len); |
1688 | if (next) { | |
a604ec7e AV |
1689 | sum = csum_block_add(sum, next, off); |
1690 | off += v.iov_len; | |
1691 | } | |
c693cc46 | 1692 | next ? 0 : v.iov_len; |
a604ec7e AV |
1693 | }), ({ |
1694 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1695 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
1696 | p + v.bv_offset, v.bv_len, | |
1697 | sum, off); | |
a604ec7e | 1698 | kunmap_atomic(p); |
a604ec7e AV |
1699 | off += v.bv_len; |
1700 | }),({ | |
f9152895 AV |
1701 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
1702 | v.iov_base, v.iov_len, | |
1703 | sum, off); | |
a604ec7e | 1704 | off += v.iov_len; |
7ff50620 DH |
1705 | }), ({ |
1706 | char *p = kmap_atomic(v.bv_page); | |
1707 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, | |
1708 | p + v.bv_offset, v.bv_len, | |
1709 | sum, off); | |
1710 | kunmap_atomic(p); | |
1711 | off += v.bv_len; | |
a604ec7e AV |
1712 | }) |
1713 | ) | |
1714 | *csum = sum; | |
1715 | return bytes; | |
1716 | } | |
1717 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1718 | ||
cbbd26b8 AV |
1719 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, |
1720 | struct iov_iter *i) | |
1721 | { | |
1722 | char *to = addr; | |
1723 | __wsum sum, next; | |
1724 | size_t off = 0; | |
1725 | sum = *csum; | |
9ea9ce04 | 1726 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
cbbd26b8 AV |
1727 | WARN_ON(1); |
1728 | return false; | |
1729 | } | |
1730 | if (unlikely(i->count < bytes)) | |
1731 | return false; | |
1732 | iterate_all_kinds(i, bytes, v, ({ | |
cbbd26b8 AV |
1733 | next = csum_and_copy_from_user(v.iov_base, |
1734 | (to += v.iov_len) - v.iov_len, | |
c693cc46 AV |
1735 | v.iov_len); |
1736 | if (!next) | |
cbbd26b8 AV |
1737 | return false; |
1738 | sum = csum_block_add(sum, next, off); | |
1739 | off += v.iov_len; | |
1740 | 0; | |
1741 | }), ({ | |
1742 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1743 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
1744 | p + v.bv_offset, v.bv_len, | |
1745 | sum, off); | |
cbbd26b8 | 1746 | kunmap_atomic(p); |
cbbd26b8 AV |
1747 | off += v.bv_len; |
1748 | }),({ | |
f9152895 AV |
1749 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
1750 | v.iov_base, v.iov_len, | |
1751 | sum, off); | |
cbbd26b8 | 1752 | off += v.iov_len; |
7ff50620 DH |
1753 | }), ({ |
1754 | char *p = kmap_atomic(v.bv_page); | |
1755 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, | |
1756 | p + v.bv_offset, v.bv_len, | |
1757 | sum, off); | |
1758 | kunmap_atomic(p); | |
1759 | off += v.bv_len; | |
cbbd26b8 AV |
1760 | }) |
1761 | ) | |
1762 | *csum = sum; | |
1763 | iov_iter_advance(i, bytes); | |
1764 | return true; | |
1765 | } | |
1766 | EXPORT_SYMBOL(csum_and_copy_from_iter_full); | |
1767 | ||
52cbd23a | 1768 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
a604ec7e AV |
1769 | struct iov_iter *i) |
1770 | { | |
52cbd23a | 1771 | struct csum_state *csstate = _csstate; |
36f7a8a4 | 1772 | const char *from = addr; |
a604ec7e | 1773 | __wsum sum, next; |
52cbd23a | 1774 | size_t off; |
78e1f386 AV |
1775 | |
1776 | if (unlikely(iov_iter_is_pipe(i))) | |
52cbd23a | 1777 | return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); |
78e1f386 | 1778 | |
52cbd23a WB |
1779 | sum = csstate->csum; |
1780 | off = csstate->off; | |
78e1f386 | 1781 | if (unlikely(iov_iter_is_discard(i))) { |
241699cd AV |
1782 | WARN_ON(1); /* for now */ |
1783 | return 0; | |
1784 | } | |
a604ec7e | 1785 | iterate_and_advance(i, bytes, v, ({ |
a604ec7e | 1786 | next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, |
cbbd26b8 | 1787 | v.iov_base, |
c693cc46 AV |
1788 | v.iov_len); |
1789 | if (next) { | |
a604ec7e AV |
1790 | sum = csum_block_add(sum, next, off); |
1791 | off += v.iov_len; | |
1792 | } | |
c693cc46 | 1793 | next ? 0 : v.iov_len; |
a604ec7e AV |
1794 | }), ({ |
1795 | char *p = kmap_atomic(v.bv_page); | |
f9152895 AV |
1796 | sum = csum_and_memcpy(p + v.bv_offset, |
1797 | (from += v.bv_len) - v.bv_len, | |
1798 | v.bv_len, sum, off); | |
a604ec7e | 1799 | kunmap_atomic(p); |
a604ec7e AV |
1800 | off += v.bv_len; |
1801 | }),({ | |
f9152895 AV |
1802 | sum = csum_and_memcpy(v.iov_base, |
1803 | (from += v.iov_len) - v.iov_len, | |
1804 | v.iov_len, sum, off); | |
a604ec7e | 1805 | off += v.iov_len; |
7ff50620 DH |
1806 | }), ({ |
1807 | char *p = kmap_atomic(v.bv_page); | |
1808 | sum = csum_and_memcpy(p + v.bv_offset, | |
1809 | (from += v.bv_len) - v.bv_len, | |
1810 | v.bv_len, sum, off); | |
1811 | kunmap_atomic(p); | |
1812 | off += v.bv_len; | |
a604ec7e AV |
1813 | }) |
1814 | ) | |
52cbd23a WB |
1815 | csstate->csum = sum; |
1816 | csstate->off = off; | |
a604ec7e AV |
1817 | return bytes; |
1818 | } | |
1819 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1820 | ||
d05f4435 SG |
1821 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
1822 | struct iov_iter *i) | |
1823 | { | |
7999096f | 1824 | #ifdef CONFIG_CRYPTO_HASH |
d05f4435 SG |
1825 | struct ahash_request *hash = hashp; |
1826 | struct scatterlist sg; | |
1827 | size_t copied; | |
1828 | ||
1829 | copied = copy_to_iter(addr, bytes, i); | |
1830 | sg_init_one(&sg, addr, copied); | |
1831 | ahash_request_set_crypt(hash, &sg, NULL, copied); | |
1832 | crypto_ahash_update(hash); | |
1833 | return copied; | |
27fad74a Y |
1834 | #else |
1835 | return 0; | |
1836 | #endif | |
d05f4435 SG |
1837 | } |
1838 | EXPORT_SYMBOL(hash_and_copy_to_iter); | |
1839 | ||
62a8067a AV |
1840 | int iov_iter_npages(const struct iov_iter *i, int maxpages) |
1841 | { | |
e0f2dc40 AV |
1842 | size_t size = i->count; |
1843 | int npages = 0; | |
1844 | ||
1845 | if (!size) | |
1846 | return 0; | |
9ea9ce04 DH |
1847 | if (unlikely(iov_iter_is_discard(i))) |
1848 | return 0; | |
e0f2dc40 | 1849 | |
00e23707 | 1850 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd | 1851 | struct pipe_inode_info *pipe = i->pipe; |
8cefc107 | 1852 | unsigned int iter_head; |
241699cd | 1853 | size_t off; |
241699cd AV |
1854 | |
1855 | if (!sanity(i)) | |
1856 | return 0; | |
1857 | ||
8cefc107 | 1858 | data_start(i, &iter_head, &off); |
241699cd | 1859 | /* some of this one + all after this one */ |
8cefc107 | 1860 | npages = pipe_space_for_user(iter_head, pipe->tail, pipe); |
241699cd AV |
1861 | if (npages >= maxpages) |
1862 | return maxpages; | |
7ff50620 DH |
1863 | } else if (unlikely(iov_iter_is_xarray(i))) { |
1864 | unsigned offset; | |
1865 | ||
1866 | offset = (i->xarray_start + i->iov_offset) & ~PAGE_MASK; | |
1867 | ||
1868 | npages = 1; | |
1869 | if (size > PAGE_SIZE - offset) { | |
1870 | size -= PAGE_SIZE - offset; | |
1871 | npages += size >> PAGE_SHIFT; | |
1872 | size &= ~PAGE_MASK; | |
1873 | if (size) | |
1874 | npages++; | |
1875 | } | |
1876 | if (npages >= maxpages) | |
1877 | return maxpages; | |
241699cd | 1878 | } else iterate_all_kinds(i, size, v, ({ |
e0f2dc40 AV |
1879 | unsigned long p = (unsigned long)v.iov_base; |
1880 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
1881 | - p / PAGE_SIZE; | |
1882 | if (npages >= maxpages) | |
1883 | return maxpages; | |
1884 | 0;}),({ | |
1885 | npages++; | |
1886 | if (npages >= maxpages) | |
1887 | return maxpages; | |
a280455f AV |
1888 | }),({ |
1889 | unsigned long p = (unsigned long)v.iov_base; | |
1890 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
1891 | - p / PAGE_SIZE; | |
1892 | if (npages >= maxpages) | |
1893 | return maxpages; | |
7ff50620 DH |
1894 | }), |
1895 | 0 | |
e0f2dc40 AV |
1896 | ) |
1897 | return npages; | |
62a8067a | 1898 | } |
f67da30c | 1899 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1900 | |
1901 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1902 | { | |
1903 | *new = *old; | |
00e23707 | 1904 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1905 | WARN_ON(1); |
1906 | return NULL; | |
1907 | } | |
7ff50620 | 1908 | if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) |
9ea9ce04 | 1909 | return NULL; |
00e23707 | 1910 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1911 | return new->bvec = kmemdup(new->bvec, |
1912 | new->nr_segs * sizeof(struct bio_vec), | |
1913 | flags); | |
1914 | else | |
1915 | /* iovec and kvec have identical layout */ | |
1916 | return new->iov = kmemdup(new->iov, | |
1917 | new->nr_segs * sizeof(struct iovec), | |
1918 | flags); | |
1919 | } | |
1920 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1921 | |
bfdc5970 CH |
1922 | static int copy_compat_iovec_from_user(struct iovec *iov, |
1923 | const struct iovec __user *uvec, unsigned long nr_segs) | |
1924 | { | |
1925 | const struct compat_iovec __user *uiov = | |
1926 | (const struct compat_iovec __user *)uvec; | |
1927 | int ret = -EFAULT, i; | |
1928 | ||
a959a978 | 1929 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
bfdc5970 CH |
1930 | return -EFAULT; |
1931 | ||
1932 | for (i = 0; i < nr_segs; i++) { | |
1933 | compat_uptr_t buf; | |
1934 | compat_ssize_t len; | |
1935 | ||
1936 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); | |
1937 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); | |
1938 | ||
1939 | /* check for compat_size_t not fitting in compat_ssize_t .. */ | |
1940 | if (len < 0) { | |
1941 | ret = -EINVAL; | |
1942 | goto uaccess_end; | |
1943 | } | |
1944 | iov[i].iov_base = compat_ptr(buf); | |
1945 | iov[i].iov_len = len; | |
1946 | } | |
1947 | ||
1948 | ret = 0; | |
1949 | uaccess_end: | |
1950 | user_access_end(); | |
1951 | return ret; | |
1952 | } | |
1953 | ||
1954 | static int copy_iovec_from_user(struct iovec *iov, | |
1955 | const struct iovec __user *uvec, unsigned long nr_segs) | |
fb041b59 DL |
1956 | { |
1957 | unsigned long seg; | |
fb041b59 | 1958 | |
bfdc5970 CH |
1959 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
1960 | return -EFAULT; | |
1961 | for (seg = 0; seg < nr_segs; seg++) { | |
1962 | if ((ssize_t)iov[seg].iov_len < 0) | |
1963 | return -EINVAL; | |
fb041b59 DL |
1964 | } |
1965 | ||
bfdc5970 CH |
1966 | return 0; |
1967 | } | |
1968 | ||
1969 | struct iovec *iovec_from_user(const struct iovec __user *uvec, | |
1970 | unsigned long nr_segs, unsigned long fast_segs, | |
1971 | struct iovec *fast_iov, bool compat) | |
1972 | { | |
1973 | struct iovec *iov = fast_iov; | |
1974 | int ret; | |
1975 | ||
fb041b59 | 1976 | /* |
bfdc5970 CH |
1977 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
1978 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
1979 | * traditionally returned zero for zero segments, so... | |
fb041b59 | 1980 | */ |
bfdc5970 CH |
1981 | if (nr_segs == 0) |
1982 | return iov; | |
1983 | if (nr_segs > UIO_MAXIOV) | |
1984 | return ERR_PTR(-EINVAL); | |
fb041b59 DL |
1985 | if (nr_segs > fast_segs) { |
1986 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); | |
bfdc5970 CH |
1987 | if (!iov) |
1988 | return ERR_PTR(-ENOMEM); | |
fb041b59 | 1989 | } |
bfdc5970 CH |
1990 | |
1991 | if (compat) | |
1992 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); | |
1993 | else | |
1994 | ret = copy_iovec_from_user(iov, uvec, nr_segs); | |
1995 | if (ret) { | |
1996 | if (iov != fast_iov) | |
1997 | kfree(iov); | |
1998 | return ERR_PTR(ret); | |
1999 | } | |
2000 | ||
2001 | return iov; | |
2002 | } | |
2003 | ||
2004 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, | |
2005 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, | |
2006 | struct iov_iter *i, bool compat) | |
2007 | { | |
2008 | ssize_t total_len = 0; | |
2009 | unsigned long seg; | |
2010 | struct iovec *iov; | |
2011 | ||
2012 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); | |
2013 | if (IS_ERR(iov)) { | |
2014 | *iovp = NULL; | |
2015 | return PTR_ERR(iov); | |
fb041b59 DL |
2016 | } |
2017 | ||
2018 | /* | |
bfdc5970 CH |
2019 | * According to the Single Unix Specification we should return EINVAL if |
2020 | * an element length is < 0 when cast to ssize_t or if the total length | |
2021 | * would overflow the ssize_t return value of the system call. | |
fb041b59 DL |
2022 | * |
2023 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
2024 | * overflow case. | |
2025 | */ | |
fb041b59 | 2026 | for (seg = 0; seg < nr_segs; seg++) { |
fb041b59 DL |
2027 | ssize_t len = (ssize_t)iov[seg].iov_len; |
2028 | ||
bfdc5970 CH |
2029 | if (!access_ok(iov[seg].iov_base, len)) { |
2030 | if (iov != *iovp) | |
2031 | kfree(iov); | |
2032 | *iovp = NULL; | |
2033 | return -EFAULT; | |
fb041b59 | 2034 | } |
bfdc5970 CH |
2035 | |
2036 | if (len > MAX_RW_COUNT - total_len) { | |
2037 | len = MAX_RW_COUNT - total_len; | |
fb041b59 DL |
2038 | iov[seg].iov_len = len; |
2039 | } | |
bfdc5970 | 2040 | total_len += len; |
fb041b59 | 2041 | } |
bfdc5970 CH |
2042 | |
2043 | iov_iter_init(i, type, iov, nr_segs, total_len); | |
2044 | if (iov == *iovp) | |
2045 | *iovp = NULL; | |
2046 | else | |
2047 | *iovp = iov; | |
2048 | return total_len; | |
fb041b59 DL |
2049 | } |
2050 | ||
ffecee4f VN |
2051 | /** |
2052 | * import_iovec() - Copy an array of &struct iovec from userspace | |
2053 | * into the kernel, check that it is valid, and initialize a new | |
2054 | * &struct iov_iter iterator to access it. | |
2055 | * | |
2056 | * @type: One of %READ or %WRITE. | |
bfdc5970 | 2057 | * @uvec: Pointer to the userspace array. |
ffecee4f VN |
2058 | * @nr_segs: Number of elements in userspace array. |
2059 | * @fast_segs: Number of elements in @iov. | |
bfdc5970 | 2060 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
ffecee4f VN |
2061 | * on-stack) kernel array. |
2062 | * @i: Pointer to iterator that will be initialized on success. | |
2063 | * | |
2064 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
2065 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
2066 | * array will be allocated and the result placed in *@iov. This means that | |
2067 | * the caller may call kfree() on *@iov regardless of whether the small | |
2068 | * on-stack array was used or not (and regardless of whether this function | |
2069 | * returns an error or not). | |
2070 | * | |
87e5e6da | 2071 | * Return: Negative error code on error, bytes imported on success |
ffecee4f | 2072 | */ |
bfdc5970 | 2073 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
bc917be8 | 2074 | unsigned nr_segs, unsigned fast_segs, |
bfdc5970 | 2075 | struct iovec **iovp, struct iov_iter *i) |
bc917be8 | 2076 | { |
89cd35c5 CH |
2077 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
2078 | in_compat_syscall()); | |
bc917be8 AV |
2079 | } |
2080 | EXPORT_SYMBOL(import_iovec); | |
2081 | ||
bc917be8 AV |
2082 | int import_single_range(int rw, void __user *buf, size_t len, |
2083 | struct iovec *iov, struct iov_iter *i) | |
2084 | { | |
2085 | if (len > MAX_RW_COUNT) | |
2086 | len = MAX_RW_COUNT; | |
96d4f267 | 2087 | if (unlikely(!access_ok(buf, len))) |
bc917be8 AV |
2088 | return -EFAULT; |
2089 | ||
2090 | iov->iov_base = buf; | |
2091 | iov->iov_len = len; | |
2092 | iov_iter_init(i, rw, iov, 1, len); | |
2093 | return 0; | |
2094 | } | |
e1267585 | 2095 | EXPORT_SYMBOL(import_single_range); |
09cf698a AV |
2096 | |
2097 | int iov_iter_for_each_range(struct iov_iter *i, size_t bytes, | |
2098 | int (*f)(struct kvec *vec, void *context), | |
2099 | void *context) | |
2100 | { | |
2101 | struct kvec w; | |
2102 | int err = -EINVAL; | |
2103 | if (!bytes) | |
2104 | return 0; | |
2105 | ||
2106 | iterate_all_kinds(i, bytes, v, -EINVAL, ({ | |
2107 | w.iov_base = kmap(v.bv_page) + v.bv_offset; | |
2108 | w.iov_len = v.bv_len; | |
2109 | err = f(&w, context); | |
2110 | kunmap(v.bv_page); | |
2111 | err;}), ({ | |
2112 | w = v; | |
7ff50620 DH |
2113 | err = f(&w, context);}), ({ |
2114 | w.iov_base = kmap(v.bv_page) + v.bv_offset; | |
2115 | w.iov_len = v.bv_len; | |
2116 | err = f(&w, context); | |
2117 | kunmap(v.bv_page); | |
2118 | err;}) | |
09cf698a AV |
2119 | ) |
2120 | return err; | |
2121 | } | |
2122 | EXPORT_SYMBOL(iov_iter_for_each_range); |