]>
Commit | Line | Data |
---|---|---|
4f18cd31 | 1 | #include <linux/export.h> |
2f8b5444 | 2 | #include <linux/bvec.h> |
4f18cd31 AV |
3 | #include <linux/uio.h> |
4 | #include <linux/pagemap.h> | |
91f79c43 AV |
5 | #include <linux/slab.h> |
6 | #include <linux/vmalloc.h> | |
241699cd | 7 | #include <linux/splice.h> |
a604ec7e | 8 | #include <net/checksum.h> |
4f18cd31 | 9 | |
241699cd AV |
10 | #define PIPE_PARANOIA /* for now */ |
11 | ||
04a31165 AV |
12 | #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ |
13 | size_t left; \ | |
14 | size_t wanted = n; \ | |
15 | __p = i->iov; \ | |
16 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
17 | if (likely(__v.iov_len)) { \ | |
18 | __v.iov_base = __p->iov_base + skip; \ | |
19 | left = (STEP); \ | |
20 | __v.iov_len -= left; \ | |
21 | skip += __v.iov_len; \ | |
22 | n -= __v.iov_len; \ | |
23 | } else { \ | |
24 | left = 0; \ | |
25 | } \ | |
26 | while (unlikely(!left && n)) { \ | |
27 | __p++; \ | |
28 | __v.iov_len = min(n, __p->iov_len); \ | |
29 | if (unlikely(!__v.iov_len)) \ | |
30 | continue; \ | |
31 | __v.iov_base = __p->iov_base; \ | |
32 | left = (STEP); \ | |
33 | __v.iov_len -= left; \ | |
34 | skip = __v.iov_len; \ | |
35 | n -= __v.iov_len; \ | |
36 | } \ | |
37 | n = wanted - n; \ | |
38 | } | |
39 | ||
a280455f AV |
40 | #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ |
41 | size_t wanted = n; \ | |
42 | __p = i->kvec; \ | |
43 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
44 | if (likely(__v.iov_len)) { \ | |
45 | __v.iov_base = __p->iov_base + skip; \ | |
46 | (void)(STEP); \ | |
47 | skip += __v.iov_len; \ | |
48 | n -= __v.iov_len; \ | |
49 | } \ | |
50 | while (unlikely(n)) { \ | |
51 | __p++; \ | |
52 | __v.iov_len = min(n, __p->iov_len); \ | |
53 | if (unlikely(!__v.iov_len)) \ | |
54 | continue; \ | |
55 | __v.iov_base = __p->iov_base; \ | |
56 | (void)(STEP); \ | |
57 | skip = __v.iov_len; \ | |
58 | n -= __v.iov_len; \ | |
59 | } \ | |
60 | n = wanted; \ | |
61 | } | |
62 | ||
1bdc76ae ML |
63 | #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ |
64 | struct bvec_iter __start; \ | |
65 | __start.bi_size = n; \ | |
66 | __start.bi_bvec_done = skip; \ | |
67 | __start.bi_idx = 0; \ | |
68 | for_each_bvec(__v, i->bvec, __bi, __start) { \ | |
69 | if (!__v.bv_len) \ | |
04a31165 | 70 | continue; \ |
04a31165 | 71 | (void)(STEP); \ |
04a31165 | 72 | } \ |
04a31165 AV |
73 | } |
74 | ||
a280455f | 75 | #define iterate_all_kinds(i, n, v, I, B, K) { \ |
33844e66 AV |
76 | if (likely(n)) { \ |
77 | size_t skip = i->iov_offset; \ | |
78 | if (unlikely(i->type & ITER_BVEC)) { \ | |
79 | struct bio_vec v; \ | |
80 | struct bvec_iter __bi; \ | |
81 | iterate_bvec(i, n, v, __bi, skip, (B)) \ | |
82 | } else if (unlikely(i->type & ITER_KVEC)) { \ | |
83 | const struct kvec *kvec; \ | |
84 | struct kvec v; \ | |
85 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
9ea9ce04 | 86 | } else if (unlikely(i->type & ITER_DISCARD)) { \ |
33844e66 AV |
87 | } else { \ |
88 | const struct iovec *iov; \ | |
89 | struct iovec v; \ | |
90 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
91 | } \ | |
04a31165 AV |
92 | } \ |
93 | } | |
94 | ||
a280455f | 95 | #define iterate_and_advance(i, n, v, I, B, K) { \ |
dd254f5a AV |
96 | if (unlikely(i->count < n)) \ |
97 | n = i->count; \ | |
19f18459 | 98 | if (i->count) { \ |
dd254f5a AV |
99 | size_t skip = i->iov_offset; \ |
100 | if (unlikely(i->type & ITER_BVEC)) { \ | |
1bdc76ae | 101 | const struct bio_vec *bvec = i->bvec; \ |
dd254f5a | 102 | struct bio_vec v; \ |
1bdc76ae ML |
103 | struct bvec_iter __bi; \ |
104 | iterate_bvec(i, n, v, __bi, skip, (B)) \ | |
105 | i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ | |
106 | i->nr_segs -= i->bvec - bvec; \ | |
107 | skip = __bi.bi_bvec_done; \ | |
dd254f5a AV |
108 | } else if (unlikely(i->type & ITER_KVEC)) { \ |
109 | const struct kvec *kvec; \ | |
110 | struct kvec v; \ | |
111 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
112 | if (skip == kvec->iov_len) { \ | |
113 | kvec++; \ | |
114 | skip = 0; \ | |
115 | } \ | |
116 | i->nr_segs -= kvec - i->kvec; \ | |
117 | i->kvec = kvec; \ | |
9ea9ce04 DH |
118 | } else if (unlikely(i->type & ITER_DISCARD)) { \ |
119 | skip += n; \ | |
dd254f5a AV |
120 | } else { \ |
121 | const struct iovec *iov; \ | |
122 | struct iovec v; \ | |
123 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
124 | if (skip == iov->iov_len) { \ | |
125 | iov++; \ | |
126 | skip = 0; \ | |
127 | } \ | |
128 | i->nr_segs -= iov - i->iov; \ | |
129 | i->iov = iov; \ | |
7ce2a91e | 130 | } \ |
dd254f5a AV |
131 | i->count -= n; \ |
132 | i->iov_offset = skip; \ | |
7ce2a91e | 133 | } \ |
7ce2a91e AV |
134 | } |
135 | ||
09fc68dc AV |
136 | static int copyout(void __user *to, const void *from, size_t n) |
137 | { | |
138 | if (access_ok(VERIFY_WRITE, to, n)) { | |
139 | kasan_check_read(from, n); | |
140 | n = raw_copy_to_user(to, from, n); | |
141 | } | |
142 | return n; | |
143 | } | |
144 | ||
145 | static int copyin(void *to, const void __user *from, size_t n) | |
146 | { | |
147 | if (access_ok(VERIFY_READ, from, n)) { | |
148 | kasan_check_write(to, n); | |
149 | n = raw_copy_from_user(to, from, n); | |
150 | } | |
151 | return n; | |
152 | } | |
153 | ||
62a8067a | 154 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
155 | struct iov_iter *i) |
156 | { | |
157 | size_t skip, copy, left, wanted; | |
158 | const struct iovec *iov; | |
159 | char __user *buf; | |
160 | void *kaddr, *from; | |
161 | ||
162 | if (unlikely(bytes > i->count)) | |
163 | bytes = i->count; | |
164 | ||
165 | if (unlikely(!bytes)) | |
166 | return 0; | |
167 | ||
09fc68dc | 168 | might_fault(); |
4f18cd31 AV |
169 | wanted = bytes; |
170 | iov = i->iov; | |
171 | skip = i->iov_offset; | |
172 | buf = iov->iov_base + skip; | |
173 | copy = min(bytes, iov->iov_len - skip); | |
174 | ||
3fa6c507 | 175 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { |
4f18cd31 AV |
176 | kaddr = kmap_atomic(page); |
177 | from = kaddr + offset; | |
178 | ||
179 | /* first chunk, usually the only one */ | |
09fc68dc | 180 | left = copyout(buf, from, copy); |
4f18cd31 AV |
181 | copy -= left; |
182 | skip += copy; | |
183 | from += copy; | |
184 | bytes -= copy; | |
185 | ||
186 | while (unlikely(!left && bytes)) { | |
187 | iov++; | |
188 | buf = iov->iov_base; | |
189 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 190 | left = copyout(buf, from, copy); |
4f18cd31 AV |
191 | copy -= left; |
192 | skip = copy; | |
193 | from += copy; | |
194 | bytes -= copy; | |
195 | } | |
196 | if (likely(!bytes)) { | |
197 | kunmap_atomic(kaddr); | |
198 | goto done; | |
199 | } | |
200 | offset = from - kaddr; | |
201 | buf += copy; | |
202 | kunmap_atomic(kaddr); | |
203 | copy = min(bytes, iov->iov_len - skip); | |
204 | } | |
205 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 206 | |
4f18cd31 AV |
207 | kaddr = kmap(page); |
208 | from = kaddr + offset; | |
09fc68dc | 209 | left = copyout(buf, from, copy); |
4f18cd31 AV |
210 | copy -= left; |
211 | skip += copy; | |
212 | from += copy; | |
213 | bytes -= copy; | |
214 | while (unlikely(!left && bytes)) { | |
215 | iov++; | |
216 | buf = iov->iov_base; | |
217 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 218 | left = copyout(buf, from, copy); |
4f18cd31 AV |
219 | copy -= left; |
220 | skip = copy; | |
221 | from += copy; | |
222 | bytes -= copy; | |
223 | } | |
224 | kunmap(page); | |
3fa6c507 | 225 | |
4f18cd31 | 226 | done: |
81055e58 AV |
227 | if (skip == iov->iov_len) { |
228 | iov++; | |
229 | skip = 0; | |
230 | } | |
4f18cd31 AV |
231 | i->count -= wanted - bytes; |
232 | i->nr_segs -= iov - i->iov; | |
233 | i->iov = iov; | |
234 | i->iov_offset = skip; | |
235 | return wanted - bytes; | |
236 | } | |
4f18cd31 | 237 | |
62a8067a | 238 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
239 | struct iov_iter *i) |
240 | { | |
241 | size_t skip, copy, left, wanted; | |
242 | const struct iovec *iov; | |
243 | char __user *buf; | |
244 | void *kaddr, *to; | |
245 | ||
246 | if (unlikely(bytes > i->count)) | |
247 | bytes = i->count; | |
248 | ||
249 | if (unlikely(!bytes)) | |
250 | return 0; | |
251 | ||
09fc68dc | 252 | might_fault(); |
f0d1bec9 AV |
253 | wanted = bytes; |
254 | iov = i->iov; | |
255 | skip = i->iov_offset; | |
256 | buf = iov->iov_base + skip; | |
257 | copy = min(bytes, iov->iov_len - skip); | |
258 | ||
3fa6c507 | 259 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { |
f0d1bec9 AV |
260 | kaddr = kmap_atomic(page); |
261 | to = kaddr + offset; | |
262 | ||
263 | /* first chunk, usually the only one */ | |
09fc68dc | 264 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
265 | copy -= left; |
266 | skip += copy; | |
267 | to += copy; | |
268 | bytes -= copy; | |
269 | ||
270 | while (unlikely(!left && bytes)) { | |
271 | iov++; | |
272 | buf = iov->iov_base; | |
273 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 274 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
275 | copy -= left; |
276 | skip = copy; | |
277 | to += copy; | |
278 | bytes -= copy; | |
279 | } | |
280 | if (likely(!bytes)) { | |
281 | kunmap_atomic(kaddr); | |
282 | goto done; | |
283 | } | |
284 | offset = to - kaddr; | |
285 | buf += copy; | |
286 | kunmap_atomic(kaddr); | |
287 | copy = min(bytes, iov->iov_len - skip); | |
288 | } | |
289 | /* Too bad - revert to non-atomic kmap */ | |
3fa6c507 | 290 | |
f0d1bec9 AV |
291 | kaddr = kmap(page); |
292 | to = kaddr + offset; | |
09fc68dc | 293 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
294 | copy -= left; |
295 | skip += copy; | |
296 | to += copy; | |
297 | bytes -= copy; | |
298 | while (unlikely(!left && bytes)) { | |
299 | iov++; | |
300 | buf = iov->iov_base; | |
301 | copy = min(bytes, iov->iov_len); | |
09fc68dc | 302 | left = copyin(to, buf, copy); |
f0d1bec9 AV |
303 | copy -= left; |
304 | skip = copy; | |
305 | to += copy; | |
306 | bytes -= copy; | |
307 | } | |
308 | kunmap(page); | |
3fa6c507 | 309 | |
f0d1bec9 | 310 | done: |
81055e58 AV |
311 | if (skip == iov->iov_len) { |
312 | iov++; | |
313 | skip = 0; | |
314 | } | |
f0d1bec9 AV |
315 | i->count -= wanted - bytes; |
316 | i->nr_segs -= iov - i->iov; | |
317 | i->iov = iov; | |
318 | i->iov_offset = skip; | |
319 | return wanted - bytes; | |
320 | } | |
f0d1bec9 | 321 | |
241699cd AV |
322 | #ifdef PIPE_PARANOIA |
323 | static bool sanity(const struct iov_iter *i) | |
324 | { | |
325 | struct pipe_inode_info *pipe = i->pipe; | |
326 | int idx = i->idx; | |
327 | int next = pipe->curbuf + pipe->nrbufs; | |
328 | if (i->iov_offset) { | |
329 | struct pipe_buffer *p; | |
330 | if (unlikely(!pipe->nrbufs)) | |
331 | goto Bad; // pipe must be non-empty | |
332 | if (unlikely(idx != ((next - 1) & (pipe->buffers - 1)))) | |
333 | goto Bad; // must be at the last buffer... | |
334 | ||
335 | p = &pipe->bufs[idx]; | |
336 | if (unlikely(p->offset + p->len != i->iov_offset)) | |
337 | goto Bad; // ... at the end of segment | |
338 | } else { | |
339 | if (idx != (next & (pipe->buffers - 1))) | |
340 | goto Bad; // must be right after the last buffer | |
341 | } | |
342 | return true; | |
343 | Bad: | |
344 | printk(KERN_ERR "idx = %d, offset = %zd\n", i->idx, i->iov_offset); | |
345 | printk(KERN_ERR "curbuf = %d, nrbufs = %d, buffers = %d\n", | |
346 | pipe->curbuf, pipe->nrbufs, pipe->buffers); | |
347 | for (idx = 0; idx < pipe->buffers; idx++) | |
348 | printk(KERN_ERR "[%p %p %d %d]\n", | |
349 | pipe->bufs[idx].ops, | |
350 | pipe->bufs[idx].page, | |
351 | pipe->bufs[idx].offset, | |
352 | pipe->bufs[idx].len); | |
353 | WARN_ON(1); | |
354 | return false; | |
355 | } | |
356 | #else | |
357 | #define sanity(i) true | |
358 | #endif | |
359 | ||
360 | static inline int next_idx(int idx, struct pipe_inode_info *pipe) | |
361 | { | |
362 | return (idx + 1) & (pipe->buffers - 1); | |
363 | } | |
364 | ||
365 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, | |
366 | struct iov_iter *i) | |
367 | { | |
368 | struct pipe_inode_info *pipe = i->pipe; | |
369 | struct pipe_buffer *buf; | |
370 | size_t off; | |
371 | int idx; | |
372 | ||
373 | if (unlikely(bytes > i->count)) | |
374 | bytes = i->count; | |
375 | ||
376 | if (unlikely(!bytes)) | |
377 | return 0; | |
378 | ||
379 | if (!sanity(i)) | |
380 | return 0; | |
381 | ||
382 | off = i->iov_offset; | |
383 | idx = i->idx; | |
384 | buf = &pipe->bufs[idx]; | |
385 | if (off) { | |
386 | if (offset == off && buf->page == page) { | |
387 | /* merge with the last one */ | |
388 | buf->len += bytes; | |
389 | i->iov_offset += bytes; | |
390 | goto out; | |
391 | } | |
392 | idx = next_idx(idx, pipe); | |
393 | buf = &pipe->bufs[idx]; | |
394 | } | |
395 | if (idx == pipe->curbuf && pipe->nrbufs) | |
396 | return 0; | |
397 | pipe->nrbufs++; | |
398 | buf->ops = &page_cache_pipe_buf_ops; | |
399 | get_page(buf->page = page); | |
400 | buf->offset = offset; | |
401 | buf->len = bytes; | |
402 | i->iov_offset = offset + bytes; | |
403 | i->idx = idx; | |
404 | out: | |
405 | i->count -= bytes; | |
406 | return bytes; | |
407 | } | |
408 | ||
171a0203 AA |
409 | /* |
410 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of | |
411 | * bytes. For each iovec, fault in each page that constitutes the iovec. | |
412 | * | |
413 | * Return 0 on success, or non-zero if the memory could not be accessed (i.e. | |
414 | * because it is an invalid address). | |
415 | */ | |
d4690f1e | 416 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) |
171a0203 AA |
417 | { |
418 | size_t skip = i->iov_offset; | |
419 | const struct iovec *iov; | |
420 | int err; | |
421 | struct iovec v; | |
422 | ||
423 | if (!(i->type & (ITER_BVEC|ITER_KVEC))) { | |
424 | iterate_iovec(i, bytes, v, iov, skip, ({ | |
4bce9f6e | 425 | err = fault_in_pages_readable(v.iov_base, v.iov_len); |
171a0203 AA |
426 | if (unlikely(err)) |
427 | return err; | |
428 | 0;})) | |
429 | } | |
430 | return 0; | |
431 | } | |
d4690f1e | 432 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
171a0203 | 433 | |
aa563d7b | 434 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
71d8e532 AV |
435 | const struct iovec *iov, unsigned long nr_segs, |
436 | size_t count) | |
437 | { | |
aa563d7b DH |
438 | WARN_ON(direction & ~(READ | WRITE)); |
439 | direction &= READ | WRITE; | |
440 | ||
71d8e532 | 441 | /* It will get better. Eventually... */ |
db68ce10 | 442 | if (uaccess_kernel()) { |
aa563d7b | 443 | i->type = ITER_KVEC | direction; |
a280455f AV |
444 | i->kvec = (struct kvec *)iov; |
445 | } else { | |
aa563d7b | 446 | i->type = ITER_IOVEC | direction; |
a280455f AV |
447 | i->iov = iov; |
448 | } | |
71d8e532 AV |
449 | i->nr_segs = nr_segs; |
450 | i->iov_offset = 0; | |
451 | i->count = count; | |
452 | } | |
453 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 454 | |
62a8067a AV |
455 | static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len) |
456 | { | |
457 | char *from = kmap_atomic(page); | |
458 | memcpy(to, from + offset, len); | |
459 | kunmap_atomic(from); | |
460 | } | |
461 | ||
36f7a8a4 | 462 | static void memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len) |
62a8067a AV |
463 | { |
464 | char *to = kmap_atomic(page); | |
465 | memcpy(to + offset, from, len); | |
466 | kunmap_atomic(to); | |
467 | } | |
468 | ||
c35e0248 MW |
469 | static void memzero_page(struct page *page, size_t offset, size_t len) |
470 | { | |
471 | char *addr = kmap_atomic(page); | |
472 | memset(addr + offset, 0, len); | |
473 | kunmap_atomic(addr); | |
474 | } | |
475 | ||
241699cd AV |
476 | static inline bool allocated(struct pipe_buffer *buf) |
477 | { | |
478 | return buf->ops == &default_pipe_buf_ops; | |
479 | } | |
480 | ||
481 | static inline void data_start(const struct iov_iter *i, int *idxp, size_t *offp) | |
482 | { | |
483 | size_t off = i->iov_offset; | |
484 | int idx = i->idx; | |
485 | if (off && (!allocated(&i->pipe->bufs[idx]) || off == PAGE_SIZE)) { | |
486 | idx = next_idx(idx, i->pipe); | |
487 | off = 0; | |
488 | } | |
489 | *idxp = idx; | |
490 | *offp = off; | |
491 | } | |
492 | ||
493 | static size_t push_pipe(struct iov_iter *i, size_t size, | |
494 | int *idxp, size_t *offp) | |
495 | { | |
496 | struct pipe_inode_info *pipe = i->pipe; | |
497 | size_t off; | |
498 | int idx; | |
499 | ssize_t left; | |
500 | ||
501 | if (unlikely(size > i->count)) | |
502 | size = i->count; | |
503 | if (unlikely(!size)) | |
504 | return 0; | |
505 | ||
506 | left = size; | |
507 | data_start(i, &idx, &off); | |
508 | *idxp = idx; | |
509 | *offp = off; | |
510 | if (off) { | |
511 | left -= PAGE_SIZE - off; | |
512 | if (left <= 0) { | |
513 | pipe->bufs[idx].len += size; | |
514 | return size; | |
515 | } | |
516 | pipe->bufs[idx].len = PAGE_SIZE; | |
517 | idx = next_idx(idx, pipe); | |
518 | } | |
519 | while (idx != pipe->curbuf || !pipe->nrbufs) { | |
520 | struct page *page = alloc_page(GFP_USER); | |
521 | if (!page) | |
522 | break; | |
523 | pipe->nrbufs++; | |
524 | pipe->bufs[idx].ops = &default_pipe_buf_ops; | |
525 | pipe->bufs[idx].page = page; | |
526 | pipe->bufs[idx].offset = 0; | |
527 | if (left <= PAGE_SIZE) { | |
528 | pipe->bufs[idx].len = left; | |
529 | return size; | |
530 | } | |
531 | pipe->bufs[idx].len = PAGE_SIZE; | |
532 | left -= PAGE_SIZE; | |
533 | idx = next_idx(idx, pipe); | |
534 | } | |
535 | return size - left; | |
536 | } | |
537 | ||
538 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, | |
539 | struct iov_iter *i) | |
540 | { | |
541 | struct pipe_inode_info *pipe = i->pipe; | |
542 | size_t n, off; | |
543 | int idx; | |
544 | ||
545 | if (!sanity(i)) | |
546 | return 0; | |
547 | ||
548 | bytes = n = push_pipe(i, bytes, &idx, &off); | |
549 | if (unlikely(!n)) | |
550 | return 0; | |
551 | for ( ; n; idx = next_idx(idx, pipe), off = 0) { | |
552 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); | |
553 | memcpy_to_page(pipe->bufs[idx].page, off, addr, chunk); | |
554 | i->idx = idx; | |
555 | i->iov_offset = off + chunk; | |
556 | n -= chunk; | |
557 | addr += chunk; | |
558 | } | |
559 | i->count -= bytes; | |
560 | return bytes; | |
561 | } | |
562 | ||
aa28de27 | 563 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 564 | { |
36f7a8a4 | 565 | const char *from = addr; |
00e23707 | 566 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 567 | return copy_pipe_to_iter(addr, bytes, i); |
09fc68dc AV |
568 | if (iter_is_iovec(i)) |
569 | might_fault(); | |
3d4d3e48 | 570 | iterate_and_advance(i, bytes, v, |
09fc68dc | 571 | copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
3d4d3e48 | 572 | memcpy_to_page(v.bv_page, v.bv_offset, |
a280455f AV |
573 | (from += v.bv_len) - v.bv_len, v.bv_len), |
574 | memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len) | |
3d4d3e48 | 575 | ) |
62a8067a | 576 | |
3d4d3e48 | 577 | return bytes; |
c35e0248 | 578 | } |
aa28de27 | 579 | EXPORT_SYMBOL(_copy_to_iter); |
c35e0248 | 580 | |
8780356e DW |
581 | #ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE |
582 | static int copyout_mcsafe(void __user *to, const void *from, size_t n) | |
583 | { | |
584 | if (access_ok(VERIFY_WRITE, to, n)) { | |
585 | kasan_check_read(from, n); | |
586 | n = copy_to_user_mcsafe((__force void *) to, from, n); | |
587 | } | |
588 | return n; | |
589 | } | |
590 | ||
591 | static unsigned long memcpy_mcsafe_to_page(struct page *page, size_t offset, | |
592 | const char *from, size_t len) | |
593 | { | |
594 | unsigned long ret; | |
595 | char *to; | |
596 | ||
597 | to = kmap_atomic(page); | |
598 | ret = memcpy_mcsafe(to + offset, from, len); | |
599 | kunmap_atomic(to); | |
600 | ||
601 | return ret; | |
602 | } | |
603 | ||
ca146f6f DW |
604 | static size_t copy_pipe_to_iter_mcsafe(const void *addr, size_t bytes, |
605 | struct iov_iter *i) | |
606 | { | |
607 | struct pipe_inode_info *pipe = i->pipe; | |
608 | size_t n, off, xfer = 0; | |
609 | int idx; | |
610 | ||
611 | if (!sanity(i)) | |
612 | return 0; | |
613 | ||
614 | bytes = n = push_pipe(i, bytes, &idx, &off); | |
615 | if (unlikely(!n)) | |
616 | return 0; | |
617 | for ( ; n; idx = next_idx(idx, pipe), off = 0) { | |
618 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); | |
619 | unsigned long rem; | |
620 | ||
621 | rem = memcpy_mcsafe_to_page(pipe->bufs[idx].page, off, addr, | |
622 | chunk); | |
623 | i->idx = idx; | |
624 | i->iov_offset = off + chunk - rem; | |
625 | xfer += chunk - rem; | |
626 | if (rem) | |
627 | break; | |
628 | n -= chunk; | |
629 | addr += chunk; | |
630 | } | |
631 | i->count -= xfer; | |
632 | return xfer; | |
633 | } | |
634 | ||
bf3eeb9b DW |
635 | /** |
636 | * _copy_to_iter_mcsafe - copy to user with source-read error exception handling | |
637 | * @addr: source kernel address | |
638 | * @bytes: total transfer length | |
639 | * @iter: destination iterator | |
640 | * | |
641 | * The pmem driver arranges for filesystem-dax to use this facility via | |
642 | * dax_copy_to_iter() for protecting read/write to persistent memory. | |
643 | * Unless / until an architecture can guarantee identical performance | |
644 | * between _copy_to_iter_mcsafe() and _copy_to_iter() it would be a | |
645 | * performance regression to switch more users to the mcsafe version. | |
646 | * | |
647 | * Otherwise, the main differences between this and typical _copy_to_iter(). | |
648 | * | |
649 | * * Typical tail/residue handling after a fault retries the copy | |
650 | * byte-by-byte until the fault happens again. Re-triggering machine | |
651 | * checks is potentially fatal so the implementation uses source | |
652 | * alignment and poison alignment assumptions to avoid re-triggering | |
653 | * hardware exceptions. | |
654 | * | |
655 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. | |
656 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return | |
657 | * a short copy. | |
658 | * | |
659 | * See MCSAFE_TEST for self-test. | |
660 | */ | |
8780356e DW |
661 | size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i) |
662 | { | |
663 | const char *from = addr; | |
664 | unsigned long rem, curr_addr, s_addr = (unsigned long) addr; | |
665 | ||
00e23707 | 666 | if (unlikely(iov_iter_is_pipe(i))) |
ca146f6f | 667 | return copy_pipe_to_iter_mcsafe(addr, bytes, i); |
8780356e DW |
668 | if (iter_is_iovec(i)) |
669 | might_fault(); | |
670 | iterate_and_advance(i, bytes, v, | |
671 | copyout_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), | |
672 | ({ | |
673 | rem = memcpy_mcsafe_to_page(v.bv_page, v.bv_offset, | |
674 | (from += v.bv_len) - v.bv_len, v.bv_len); | |
675 | if (rem) { | |
676 | curr_addr = (unsigned long) from; | |
677 | bytes = curr_addr - s_addr - rem; | |
678 | return bytes; | |
679 | } | |
680 | }), | |
681 | ({ | |
682 | rem = memcpy_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len, | |
683 | v.iov_len); | |
684 | if (rem) { | |
685 | curr_addr = (unsigned long) from; | |
686 | bytes = curr_addr - s_addr - rem; | |
687 | return bytes; | |
688 | } | |
689 | }) | |
690 | ) | |
691 | ||
692 | return bytes; | |
693 | } | |
694 | EXPORT_SYMBOL_GPL(_copy_to_iter_mcsafe); | |
695 | #endif /* CONFIG_ARCH_HAS_UACCESS_MCSAFE */ | |
696 | ||
aa28de27 | 697 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 698 | { |
0dbca9a4 | 699 | char *to = addr; |
00e23707 | 700 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
701 | WARN_ON(1); |
702 | return 0; | |
703 | } | |
09fc68dc AV |
704 | if (iter_is_iovec(i)) |
705 | might_fault(); | |
0dbca9a4 | 706 | iterate_and_advance(i, bytes, v, |
09fc68dc | 707 | copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
0dbca9a4 | 708 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
a280455f AV |
709 | v.bv_offset, v.bv_len), |
710 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) | |
0dbca9a4 AV |
711 | ) |
712 | ||
713 | return bytes; | |
c35e0248 | 714 | } |
aa28de27 | 715 | EXPORT_SYMBOL(_copy_from_iter); |
c35e0248 | 716 | |
aa28de27 | 717 | bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) |
cbbd26b8 AV |
718 | { |
719 | char *to = addr; | |
00e23707 | 720 | if (unlikely(iov_iter_is_pipe(i))) { |
cbbd26b8 AV |
721 | WARN_ON(1); |
722 | return false; | |
723 | } | |
33844e66 | 724 | if (unlikely(i->count < bytes)) |
cbbd26b8 AV |
725 | return false; |
726 | ||
09fc68dc AV |
727 | if (iter_is_iovec(i)) |
728 | might_fault(); | |
cbbd26b8 | 729 | iterate_all_kinds(i, bytes, v, ({ |
09fc68dc | 730 | if (copyin((to += v.iov_len) - v.iov_len, |
cbbd26b8 AV |
731 | v.iov_base, v.iov_len)) |
732 | return false; | |
733 | 0;}), | |
734 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
735 | v.bv_offset, v.bv_len), | |
736 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) | |
737 | ) | |
738 | ||
739 | iov_iter_advance(i, bytes); | |
740 | return true; | |
741 | } | |
aa28de27 | 742 | EXPORT_SYMBOL(_copy_from_iter_full); |
cbbd26b8 | 743 | |
aa28de27 | 744 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
aa583096 AV |
745 | { |
746 | char *to = addr; | |
00e23707 | 747 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
748 | WARN_ON(1); |
749 | return 0; | |
750 | } | |
aa583096 | 751 | iterate_and_advance(i, bytes, v, |
3f763453 | 752 | __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
aa583096 AV |
753 | v.iov_base, v.iov_len), |
754 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
755 | v.bv_offset, v.bv_len), | |
756 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) | |
757 | ) | |
758 | ||
759 | return bytes; | |
760 | } | |
aa28de27 | 761 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
aa583096 | 762 | |
0aed55af | 763 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
abd08d7d DW |
764 | /** |
765 | * _copy_from_iter_flushcache - write destination through cpu cache | |
766 | * @addr: destination kernel address | |
767 | * @bytes: total transfer length | |
768 | * @iter: source iterator | |
769 | * | |
770 | * The pmem driver arranges for filesystem-dax to use this facility via | |
771 | * dax_copy_from_iter() for ensuring that writes to persistent memory | |
772 | * are flushed through the CPU cache. It is differentiated from | |
773 | * _copy_from_iter_nocache() in that guarantees all data is flushed for | |
774 | * all iterator types. The _copy_from_iter_nocache() only attempts to | |
775 | * bypass the cache for the ITER_IOVEC case, and on some archs may use | |
776 | * instructions that strand dirty-data in the cache. | |
777 | */ | |
6a37e940 | 778 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
0aed55af DW |
779 | { |
780 | char *to = addr; | |
00e23707 | 781 | if (unlikely(iov_iter_is_pipe(i))) { |
0aed55af DW |
782 | WARN_ON(1); |
783 | return 0; | |
784 | } | |
785 | iterate_and_advance(i, bytes, v, | |
786 | __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, | |
787 | v.iov_base, v.iov_len), | |
788 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, | |
789 | v.bv_offset, v.bv_len), | |
790 | memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, | |
791 | v.iov_len) | |
792 | ) | |
793 | ||
794 | return bytes; | |
795 | } | |
6a37e940 | 796 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
0aed55af DW |
797 | #endif |
798 | ||
aa28de27 | 799 | bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) |
cbbd26b8 AV |
800 | { |
801 | char *to = addr; | |
00e23707 | 802 | if (unlikely(iov_iter_is_pipe(i))) { |
cbbd26b8 AV |
803 | WARN_ON(1); |
804 | return false; | |
805 | } | |
33844e66 | 806 | if (unlikely(i->count < bytes)) |
cbbd26b8 AV |
807 | return false; |
808 | iterate_all_kinds(i, bytes, v, ({ | |
3f763453 | 809 | if (__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
cbbd26b8 AV |
810 | v.iov_base, v.iov_len)) |
811 | return false; | |
812 | 0;}), | |
813 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
814 | v.bv_offset, v.bv_len), | |
815 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) | |
816 | ) | |
817 | ||
818 | iov_iter_advance(i, bytes); | |
819 | return true; | |
820 | } | |
aa28de27 | 821 | EXPORT_SYMBOL(_copy_from_iter_full_nocache); |
cbbd26b8 | 822 | |
72e809ed AV |
823 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
824 | { | |
a90bcb86 PP |
825 | struct page *head = compound_head(page); |
826 | size_t v = n + offset + page_address(page) - page_address(head); | |
827 | ||
828 | if (likely(n <= v && v <= (PAGE_SIZE << compound_order(head)))) | |
72e809ed AV |
829 | return true; |
830 | WARN_ON(1); | |
831 | return false; | |
832 | } | |
cbbd26b8 | 833 | |
62a8067a AV |
834 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
835 | struct iov_iter *i) | |
836 | { | |
72e809ed AV |
837 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
838 | return 0; | |
d271524a AV |
839 | if (i->type & (ITER_BVEC|ITER_KVEC)) { |
840 | void *kaddr = kmap_atomic(page); | |
841 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); | |
842 | kunmap_atomic(kaddr); | |
843 | return wanted; | |
9ea9ce04 DH |
844 | } else if (unlikely(iov_iter_is_discard(i))) |
845 | return bytes; | |
846 | else if (likely(!iov_iter_is_pipe(i))) | |
62a8067a | 847 | return copy_page_to_iter_iovec(page, offset, bytes, i); |
241699cd AV |
848 | else |
849 | return copy_page_to_iter_pipe(page, offset, bytes, i); | |
62a8067a AV |
850 | } |
851 | EXPORT_SYMBOL(copy_page_to_iter); | |
852 | ||
853 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
854 | struct iov_iter *i) | |
855 | { | |
72e809ed AV |
856 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
857 | return 0; | |
9ea9ce04 | 858 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
859 | WARN_ON(1); |
860 | return 0; | |
861 | } | |
a280455f | 862 | if (i->type & (ITER_BVEC|ITER_KVEC)) { |
d271524a | 863 | void *kaddr = kmap_atomic(page); |
aa28de27 | 864 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
d271524a AV |
865 | kunmap_atomic(kaddr); |
866 | return wanted; | |
867 | } else | |
62a8067a AV |
868 | return copy_page_from_iter_iovec(page, offset, bytes, i); |
869 | } | |
870 | EXPORT_SYMBOL(copy_page_from_iter); | |
871 | ||
241699cd AV |
872 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
873 | { | |
874 | struct pipe_inode_info *pipe = i->pipe; | |
875 | size_t n, off; | |
876 | int idx; | |
877 | ||
878 | if (!sanity(i)) | |
879 | return 0; | |
880 | ||
881 | bytes = n = push_pipe(i, bytes, &idx, &off); | |
882 | if (unlikely(!n)) | |
883 | return 0; | |
884 | ||
885 | for ( ; n; idx = next_idx(idx, pipe), off = 0) { | |
886 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); | |
887 | memzero_page(pipe->bufs[idx].page, off, chunk); | |
888 | i->idx = idx; | |
889 | i->iov_offset = off + chunk; | |
890 | n -= chunk; | |
891 | } | |
892 | i->count -= bytes; | |
893 | return bytes; | |
894 | } | |
895 | ||
c35e0248 MW |
896 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
897 | { | |
00e23707 | 898 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 899 | return pipe_zero(bytes, i); |
8442fa46 | 900 | iterate_and_advance(i, bytes, v, |
09fc68dc | 901 | clear_user(v.iov_base, v.iov_len), |
a280455f AV |
902 | memzero_page(v.bv_page, v.bv_offset, v.bv_len), |
903 | memset(v.iov_base, 0, v.iov_len) | |
8442fa46 AV |
904 | ) |
905 | ||
906 | return bytes; | |
c35e0248 MW |
907 | } |
908 | EXPORT_SYMBOL(iov_iter_zero); | |
909 | ||
62a8067a AV |
910 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
911 | struct iov_iter *i, unsigned long offset, size_t bytes) | |
912 | { | |
04a31165 | 913 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
72e809ed AV |
914 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
915 | kunmap_atomic(kaddr); | |
916 | return 0; | |
917 | } | |
9ea9ce04 | 918 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
919 | kunmap_atomic(kaddr); |
920 | WARN_ON(1); | |
921 | return 0; | |
922 | } | |
04a31165 | 923 | iterate_all_kinds(i, bytes, v, |
09fc68dc | 924 | copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
04a31165 | 925 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, |
a280455f AV |
926 | v.bv_offset, v.bv_len), |
927 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) | |
04a31165 AV |
928 | ) |
929 | kunmap_atomic(kaddr); | |
930 | return bytes; | |
62a8067a AV |
931 | } |
932 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); | |
933 | ||
b9dc6f65 AV |
934 | static inline void pipe_truncate(struct iov_iter *i) |
935 | { | |
936 | struct pipe_inode_info *pipe = i->pipe; | |
937 | if (pipe->nrbufs) { | |
938 | size_t off = i->iov_offset; | |
939 | int idx = i->idx; | |
940 | int nrbufs = (idx - pipe->curbuf) & (pipe->buffers - 1); | |
941 | if (off) { | |
942 | pipe->bufs[idx].len = off - pipe->bufs[idx].offset; | |
943 | idx = next_idx(idx, pipe); | |
944 | nrbufs++; | |
945 | } | |
946 | while (pipe->nrbufs > nrbufs) { | |
947 | pipe_buf_release(pipe, &pipe->bufs[idx]); | |
948 | idx = next_idx(idx, pipe); | |
949 | pipe->nrbufs--; | |
950 | } | |
951 | } | |
952 | } | |
953 | ||
241699cd AV |
954 | static void pipe_advance(struct iov_iter *i, size_t size) |
955 | { | |
956 | struct pipe_inode_info *pipe = i->pipe; | |
241699cd AV |
957 | if (unlikely(i->count < size)) |
958 | size = i->count; | |
241699cd | 959 | if (size) { |
b9dc6f65 AV |
960 | struct pipe_buffer *buf; |
961 | size_t off = i->iov_offset, left = size; | |
962 | int idx = i->idx; | |
241699cd | 963 | if (off) /* make it relative to the beginning of buffer */ |
b9dc6f65 | 964 | left += off - pipe->bufs[idx].offset; |
241699cd AV |
965 | while (1) { |
966 | buf = &pipe->bufs[idx]; | |
b9dc6f65 | 967 | if (left <= buf->len) |
241699cd | 968 | break; |
b9dc6f65 | 969 | left -= buf->len; |
241699cd AV |
970 | idx = next_idx(idx, pipe); |
971 | } | |
241699cd | 972 | i->idx = idx; |
b9dc6f65 | 973 | i->iov_offset = buf->offset + left; |
241699cd | 974 | } |
b9dc6f65 AV |
975 | i->count -= size; |
976 | /* ... and discard everything past that point */ | |
977 | pipe_truncate(i); | |
241699cd AV |
978 | } |
979 | ||
62a8067a AV |
980 | void iov_iter_advance(struct iov_iter *i, size_t size) |
981 | { | |
00e23707 | 982 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
983 | pipe_advance(i, size); |
984 | return; | |
985 | } | |
9ea9ce04 DH |
986 | if (unlikely(iov_iter_is_discard(i))) { |
987 | i->count -= size; | |
988 | return; | |
989 | } | |
a280455f | 990 | iterate_and_advance(i, size, v, 0, 0, 0) |
62a8067a AV |
991 | } |
992 | EXPORT_SYMBOL(iov_iter_advance); | |
993 | ||
27c0e374 AV |
994 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
995 | { | |
996 | if (!unroll) | |
997 | return; | |
5b47d59a AV |
998 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
999 | return; | |
27c0e374 | 1000 | i->count += unroll; |
00e23707 | 1001 | if (unlikely(iov_iter_is_pipe(i))) { |
27c0e374 AV |
1002 | struct pipe_inode_info *pipe = i->pipe; |
1003 | int idx = i->idx; | |
1004 | size_t off = i->iov_offset; | |
1005 | while (1) { | |
1006 | size_t n = off - pipe->bufs[idx].offset; | |
1007 | if (unroll < n) { | |
4fa55cef | 1008 | off -= unroll; |
27c0e374 AV |
1009 | break; |
1010 | } | |
1011 | unroll -= n; | |
1012 | if (!unroll && idx == i->start_idx) { | |
1013 | off = 0; | |
1014 | break; | |
1015 | } | |
1016 | if (!idx--) | |
1017 | idx = pipe->buffers - 1; | |
1018 | off = pipe->bufs[idx].offset + pipe->bufs[idx].len; | |
1019 | } | |
1020 | i->iov_offset = off; | |
1021 | i->idx = idx; | |
1022 | pipe_truncate(i); | |
1023 | return; | |
1024 | } | |
9ea9ce04 DH |
1025 | if (unlikely(iov_iter_is_discard(i))) |
1026 | return; | |
27c0e374 AV |
1027 | if (unroll <= i->iov_offset) { |
1028 | i->iov_offset -= unroll; | |
1029 | return; | |
1030 | } | |
1031 | unroll -= i->iov_offset; | |
00e23707 | 1032 | if (iov_iter_is_bvec(i)) { |
27c0e374 AV |
1033 | const struct bio_vec *bvec = i->bvec; |
1034 | while (1) { | |
1035 | size_t n = (--bvec)->bv_len; | |
1036 | i->nr_segs++; | |
1037 | if (unroll <= n) { | |
1038 | i->bvec = bvec; | |
1039 | i->iov_offset = n - unroll; | |
1040 | return; | |
1041 | } | |
1042 | unroll -= n; | |
1043 | } | |
1044 | } else { /* same logics for iovec and kvec */ | |
1045 | const struct iovec *iov = i->iov; | |
1046 | while (1) { | |
1047 | size_t n = (--iov)->iov_len; | |
1048 | i->nr_segs++; | |
1049 | if (unroll <= n) { | |
1050 | i->iov = iov; | |
1051 | i->iov_offset = n - unroll; | |
1052 | return; | |
1053 | } | |
1054 | unroll -= n; | |
1055 | } | |
1056 | } | |
1057 | } | |
1058 | EXPORT_SYMBOL(iov_iter_revert); | |
1059 | ||
62a8067a AV |
1060 | /* |
1061 | * Return the count of just the current iov_iter segment. | |
1062 | */ | |
1063 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
1064 | { | |
00e23707 | 1065 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1066 | return i->count; // it is a silly place, anyway |
62a8067a AV |
1067 | if (i->nr_segs == 1) |
1068 | return i->count; | |
9ea9ce04 DH |
1069 | if (unlikely(iov_iter_is_discard(i))) |
1070 | return i->count; | |
00e23707 | 1071 | else if (iov_iter_is_bvec(i)) |
62a8067a | 1072 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
ad0eab92 PM |
1073 | else |
1074 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
62a8067a AV |
1075 | } |
1076 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
1077 | ||
aa563d7b | 1078 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
05afcb77 | 1079 | const struct kvec *kvec, unsigned long nr_segs, |
abb78f87 AV |
1080 | size_t count) |
1081 | { | |
aa563d7b DH |
1082 | WARN_ON(direction & ~(READ | WRITE)); |
1083 | i->type = ITER_KVEC | (direction & (READ | WRITE)); | |
05afcb77 | 1084 | i->kvec = kvec; |
abb78f87 AV |
1085 | i->nr_segs = nr_segs; |
1086 | i->iov_offset = 0; | |
1087 | i->count = count; | |
1088 | } | |
1089 | EXPORT_SYMBOL(iov_iter_kvec); | |
1090 | ||
aa563d7b | 1091 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
05afcb77 AV |
1092 | const struct bio_vec *bvec, unsigned long nr_segs, |
1093 | size_t count) | |
1094 | { | |
aa563d7b DH |
1095 | WARN_ON(direction & ~(READ | WRITE)); |
1096 | i->type = ITER_BVEC | (direction & (READ | WRITE)); | |
05afcb77 AV |
1097 | i->bvec = bvec; |
1098 | i->nr_segs = nr_segs; | |
1099 | i->iov_offset = 0; | |
1100 | i->count = count; | |
1101 | } | |
1102 | EXPORT_SYMBOL(iov_iter_bvec); | |
1103 | ||
aa563d7b | 1104 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
241699cd AV |
1105 | struct pipe_inode_info *pipe, |
1106 | size_t count) | |
1107 | { | |
aa563d7b | 1108 | BUG_ON(direction != READ); |
b9dc6f65 | 1109 | WARN_ON(pipe->nrbufs == pipe->buffers); |
aa563d7b | 1110 | i->type = ITER_PIPE | READ; |
241699cd AV |
1111 | i->pipe = pipe; |
1112 | i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); | |
1113 | i->iov_offset = 0; | |
1114 | i->count = count; | |
27c0e374 | 1115 | i->start_idx = i->idx; |
241699cd AV |
1116 | } |
1117 | EXPORT_SYMBOL(iov_iter_pipe); | |
1118 | ||
9ea9ce04 DH |
1119 | /** |
1120 | * iov_iter_discard - Initialise an I/O iterator that discards data | |
1121 | * @i: The iterator to initialise. | |
1122 | * @direction: The direction of the transfer. | |
1123 | * @count: The size of the I/O buffer in bytes. | |
1124 | * | |
1125 | * Set up an I/O iterator that just discards everything that's written to it. | |
1126 | * It's only available as a READ iterator. | |
1127 | */ | |
1128 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) | |
1129 | { | |
1130 | BUG_ON(direction != READ); | |
1131 | i->type = ITER_DISCARD | READ; | |
1132 | i->count = count; | |
1133 | i->iov_offset = 0; | |
1134 | } | |
1135 | EXPORT_SYMBOL(iov_iter_discard); | |
1136 | ||
62a8067a AV |
1137 | unsigned long iov_iter_alignment(const struct iov_iter *i) |
1138 | { | |
04a31165 AV |
1139 | unsigned long res = 0; |
1140 | size_t size = i->count; | |
1141 | ||
00e23707 | 1142 | if (unlikely(iov_iter_is_pipe(i))) { |
33844e66 | 1143 | if (size && i->iov_offset && allocated(&i->pipe->bufs[i->idx])) |
241699cd AV |
1144 | return size | i->iov_offset; |
1145 | return size; | |
1146 | } | |
04a31165 AV |
1147 | iterate_all_kinds(i, size, v, |
1148 | (res |= (unsigned long)v.iov_base | v.iov_len, 0), | |
a280455f AV |
1149 | res |= v.bv_offset | v.bv_len, |
1150 | res |= (unsigned long)v.iov_base | v.iov_len | |
04a31165 AV |
1151 | ) |
1152 | return res; | |
62a8067a AV |
1153 | } |
1154 | EXPORT_SYMBOL(iov_iter_alignment); | |
1155 | ||
357f435d AV |
1156 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
1157 | { | |
33844e66 | 1158 | unsigned long res = 0; |
357f435d | 1159 | size_t size = i->count; |
357f435d | 1160 | |
9ea9ce04 | 1161 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1162 | WARN_ON(1); |
1163 | return ~0U; | |
1164 | } | |
1165 | ||
357f435d AV |
1166 | iterate_all_kinds(i, size, v, |
1167 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | | |
1168 | (size != v.iov_len ? size : 0), 0), | |
1169 | (res |= (!res ? 0 : (unsigned long)v.bv_offset) | | |
1170 | (size != v.bv_len ? size : 0)), | |
1171 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | | |
1172 | (size != v.iov_len ? size : 0)) | |
1173 | ); | |
33844e66 | 1174 | return res; |
357f435d AV |
1175 | } |
1176 | EXPORT_SYMBOL(iov_iter_gap_alignment); | |
1177 | ||
e76b6312 | 1178 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
241699cd AV |
1179 | size_t maxsize, |
1180 | struct page **pages, | |
1181 | int idx, | |
1182 | size_t *start) | |
1183 | { | |
1184 | struct pipe_inode_info *pipe = i->pipe; | |
1689c73a | 1185 | ssize_t n = push_pipe(i, maxsize, &idx, start); |
241699cd AV |
1186 | if (!n) |
1187 | return -EFAULT; | |
1188 | ||
1189 | maxsize = n; | |
1190 | n += *start; | |
1689c73a | 1191 | while (n > 0) { |
241699cd AV |
1192 | get_page(*pages++ = pipe->bufs[idx].page); |
1193 | idx = next_idx(idx, pipe); | |
1194 | n -= PAGE_SIZE; | |
1195 | } | |
1196 | ||
1197 | return maxsize; | |
1198 | } | |
1199 | ||
1200 | static ssize_t pipe_get_pages(struct iov_iter *i, | |
1201 | struct page **pages, size_t maxsize, unsigned maxpages, | |
1202 | size_t *start) | |
1203 | { | |
1204 | unsigned npages; | |
1205 | size_t capacity; | |
1206 | int idx; | |
1207 | ||
33844e66 AV |
1208 | if (!maxsize) |
1209 | return 0; | |
1210 | ||
241699cd AV |
1211 | if (!sanity(i)) |
1212 | return -EFAULT; | |
1213 | ||
1214 | data_start(i, &idx, start); | |
1215 | /* some of this one + all after this one */ | |
1216 | npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1; | |
1217 | capacity = min(npages,maxpages) * PAGE_SIZE - *start; | |
1218 | ||
1219 | return __pipe_get_pages(i, min(maxsize, capacity), pages, idx, start); | |
1220 | } | |
1221 | ||
62a8067a | 1222 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
2c80929c | 1223 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
1224 | size_t *start) |
1225 | { | |
e5393fae AV |
1226 | if (maxsize > i->count) |
1227 | maxsize = i->count; | |
1228 | ||
00e23707 | 1229 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1230 | return pipe_get_pages(i, pages, maxsize, maxpages, start); |
9ea9ce04 DH |
1231 | if (unlikely(iov_iter_is_discard(i))) |
1232 | return -EFAULT; | |
1233 | ||
e5393fae AV |
1234 | iterate_all_kinds(i, maxsize, v, ({ |
1235 | unsigned long addr = (unsigned long)v.iov_base; | |
1236 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
1237 | int n; | |
1238 | int res; | |
1239 | ||
1240 | if (len > maxpages * PAGE_SIZE) | |
1241 | len = maxpages * PAGE_SIZE; | |
1242 | addr &= ~(PAGE_SIZE - 1); | |
1243 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
00e23707 | 1244 | res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, pages); |
e5393fae AV |
1245 | if (unlikely(res < 0)) |
1246 | return res; | |
1247 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
1248 | 0;}),({ | |
1249 | /* can't be more than PAGE_SIZE */ | |
1250 | *start = v.bv_offset; | |
1251 | get_page(*pages = v.bv_page); | |
1252 | return v.bv_len; | |
a280455f AV |
1253 | }),({ |
1254 | return -EFAULT; | |
e5393fae AV |
1255 | }) |
1256 | ) | |
1257 | return 0; | |
62a8067a AV |
1258 | } |
1259 | EXPORT_SYMBOL(iov_iter_get_pages); | |
1260 | ||
1b17f1f2 AV |
1261 | static struct page **get_pages_array(size_t n) |
1262 | { | |
752ade68 | 1263 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); |
1b17f1f2 AV |
1264 | } |
1265 | ||
241699cd AV |
1266 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
1267 | struct page ***pages, size_t maxsize, | |
1268 | size_t *start) | |
1269 | { | |
1270 | struct page **p; | |
d7760d63 | 1271 | ssize_t n; |
241699cd AV |
1272 | int idx; |
1273 | int npages; | |
1274 | ||
33844e66 AV |
1275 | if (!maxsize) |
1276 | return 0; | |
1277 | ||
241699cd AV |
1278 | if (!sanity(i)) |
1279 | return -EFAULT; | |
1280 | ||
1281 | data_start(i, &idx, start); | |
1282 | /* some of this one + all after this one */ | |
1283 | npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1; | |
1284 | n = npages * PAGE_SIZE - *start; | |
1285 | if (maxsize > n) | |
1286 | maxsize = n; | |
1287 | else | |
1288 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); | |
1289 | p = get_pages_array(npages); | |
1290 | if (!p) | |
1291 | return -ENOMEM; | |
1292 | n = __pipe_get_pages(i, maxsize, p, idx, start); | |
1293 | if (n > 0) | |
1294 | *pages = p; | |
1295 | else | |
1296 | kvfree(p); | |
1297 | return n; | |
1298 | } | |
1299 | ||
62a8067a AV |
1300 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
1301 | struct page ***pages, size_t maxsize, | |
1302 | size_t *start) | |
1303 | { | |
1b17f1f2 AV |
1304 | struct page **p; |
1305 | ||
1306 | if (maxsize > i->count) | |
1307 | maxsize = i->count; | |
1308 | ||
00e23707 | 1309 | if (unlikely(iov_iter_is_pipe(i))) |
241699cd | 1310 | return pipe_get_pages_alloc(i, pages, maxsize, start); |
9ea9ce04 DH |
1311 | if (unlikely(iov_iter_is_discard(i))) |
1312 | return -EFAULT; | |
1313 | ||
1b17f1f2 AV |
1314 | iterate_all_kinds(i, maxsize, v, ({ |
1315 | unsigned long addr = (unsigned long)v.iov_base; | |
1316 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
1317 | int n; | |
1318 | int res; | |
1319 | ||
1320 | addr &= ~(PAGE_SIZE - 1); | |
1321 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
1322 | p = get_pages_array(n); | |
1323 | if (!p) | |
1324 | return -ENOMEM; | |
00e23707 | 1325 | res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, p); |
1b17f1f2 AV |
1326 | if (unlikely(res < 0)) { |
1327 | kvfree(p); | |
1328 | return res; | |
1329 | } | |
1330 | *pages = p; | |
1331 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
1332 | 0;}),({ | |
1333 | /* can't be more than PAGE_SIZE */ | |
1334 | *start = v.bv_offset; | |
1335 | *pages = p = get_pages_array(1); | |
1336 | if (!p) | |
1337 | return -ENOMEM; | |
1338 | get_page(*p = v.bv_page); | |
1339 | return v.bv_len; | |
a280455f AV |
1340 | }),({ |
1341 | return -EFAULT; | |
1b17f1f2 AV |
1342 | }) |
1343 | ) | |
1344 | return 0; | |
62a8067a AV |
1345 | } |
1346 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
1347 | ||
a604ec7e AV |
1348 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1349 | struct iov_iter *i) | |
1350 | { | |
1351 | char *to = addr; | |
1352 | __wsum sum, next; | |
1353 | size_t off = 0; | |
a604ec7e | 1354 | sum = *csum; |
9ea9ce04 | 1355 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1356 | WARN_ON(1); |
1357 | return 0; | |
1358 | } | |
a604ec7e AV |
1359 | iterate_and_advance(i, bytes, v, ({ |
1360 | int err = 0; | |
cbbd26b8 | 1361 | next = csum_and_copy_from_user(v.iov_base, |
a604ec7e AV |
1362 | (to += v.iov_len) - v.iov_len, |
1363 | v.iov_len, 0, &err); | |
1364 | if (!err) { | |
1365 | sum = csum_block_add(sum, next, off); | |
1366 | off += v.iov_len; | |
1367 | } | |
1368 | err ? v.iov_len : 0; | |
1369 | }), ({ | |
1370 | char *p = kmap_atomic(v.bv_page); | |
1371 | next = csum_partial_copy_nocheck(p + v.bv_offset, | |
1372 | (to += v.bv_len) - v.bv_len, | |
1373 | v.bv_len, 0); | |
1374 | kunmap_atomic(p); | |
1375 | sum = csum_block_add(sum, next, off); | |
1376 | off += v.bv_len; | |
1377 | }),({ | |
1378 | next = csum_partial_copy_nocheck(v.iov_base, | |
1379 | (to += v.iov_len) - v.iov_len, | |
1380 | v.iov_len, 0); | |
1381 | sum = csum_block_add(sum, next, off); | |
1382 | off += v.iov_len; | |
1383 | }) | |
1384 | ) | |
1385 | *csum = sum; | |
1386 | return bytes; | |
1387 | } | |
1388 | EXPORT_SYMBOL(csum_and_copy_from_iter); | |
1389 | ||
cbbd26b8 AV |
1390 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, |
1391 | struct iov_iter *i) | |
1392 | { | |
1393 | char *to = addr; | |
1394 | __wsum sum, next; | |
1395 | size_t off = 0; | |
1396 | sum = *csum; | |
9ea9ce04 | 1397 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
cbbd26b8 AV |
1398 | WARN_ON(1); |
1399 | return false; | |
1400 | } | |
1401 | if (unlikely(i->count < bytes)) | |
1402 | return false; | |
1403 | iterate_all_kinds(i, bytes, v, ({ | |
1404 | int err = 0; | |
1405 | next = csum_and_copy_from_user(v.iov_base, | |
1406 | (to += v.iov_len) - v.iov_len, | |
1407 | v.iov_len, 0, &err); | |
1408 | if (err) | |
1409 | return false; | |
1410 | sum = csum_block_add(sum, next, off); | |
1411 | off += v.iov_len; | |
1412 | 0; | |
1413 | }), ({ | |
1414 | char *p = kmap_atomic(v.bv_page); | |
1415 | next = csum_partial_copy_nocheck(p + v.bv_offset, | |
1416 | (to += v.bv_len) - v.bv_len, | |
1417 | v.bv_len, 0); | |
1418 | kunmap_atomic(p); | |
1419 | sum = csum_block_add(sum, next, off); | |
1420 | off += v.bv_len; | |
1421 | }),({ | |
1422 | next = csum_partial_copy_nocheck(v.iov_base, | |
1423 | (to += v.iov_len) - v.iov_len, | |
1424 | v.iov_len, 0); | |
1425 | sum = csum_block_add(sum, next, off); | |
1426 | off += v.iov_len; | |
1427 | }) | |
1428 | ) | |
1429 | *csum = sum; | |
1430 | iov_iter_advance(i, bytes); | |
1431 | return true; | |
1432 | } | |
1433 | EXPORT_SYMBOL(csum_and_copy_from_iter_full); | |
1434 | ||
36f7a8a4 | 1435 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, |
a604ec7e AV |
1436 | struct iov_iter *i) |
1437 | { | |
36f7a8a4 | 1438 | const char *from = addr; |
a604ec7e AV |
1439 | __wsum sum, next; |
1440 | size_t off = 0; | |
a604ec7e | 1441 | sum = *csum; |
9ea9ce04 | 1442 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
241699cd AV |
1443 | WARN_ON(1); /* for now */ |
1444 | return 0; | |
1445 | } | |
a604ec7e AV |
1446 | iterate_and_advance(i, bytes, v, ({ |
1447 | int err = 0; | |
1448 | next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, | |
cbbd26b8 | 1449 | v.iov_base, |
a604ec7e AV |
1450 | v.iov_len, 0, &err); |
1451 | if (!err) { | |
1452 | sum = csum_block_add(sum, next, off); | |
1453 | off += v.iov_len; | |
1454 | } | |
1455 | err ? v.iov_len : 0; | |
1456 | }), ({ | |
1457 | char *p = kmap_atomic(v.bv_page); | |
1458 | next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len, | |
1459 | p + v.bv_offset, | |
1460 | v.bv_len, 0); | |
1461 | kunmap_atomic(p); | |
1462 | sum = csum_block_add(sum, next, off); | |
1463 | off += v.bv_len; | |
1464 | }),({ | |
1465 | next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len, | |
1466 | v.iov_base, | |
1467 | v.iov_len, 0); | |
1468 | sum = csum_block_add(sum, next, off); | |
1469 | off += v.iov_len; | |
1470 | }) | |
1471 | ) | |
1472 | *csum = sum; | |
1473 | return bytes; | |
1474 | } | |
1475 | EXPORT_SYMBOL(csum_and_copy_to_iter); | |
1476 | ||
62a8067a AV |
1477 | int iov_iter_npages(const struct iov_iter *i, int maxpages) |
1478 | { | |
e0f2dc40 AV |
1479 | size_t size = i->count; |
1480 | int npages = 0; | |
1481 | ||
1482 | if (!size) | |
1483 | return 0; | |
9ea9ce04 DH |
1484 | if (unlikely(iov_iter_is_discard(i))) |
1485 | return 0; | |
e0f2dc40 | 1486 | |
00e23707 | 1487 | if (unlikely(iov_iter_is_pipe(i))) { |
241699cd AV |
1488 | struct pipe_inode_info *pipe = i->pipe; |
1489 | size_t off; | |
1490 | int idx; | |
1491 | ||
1492 | if (!sanity(i)) | |
1493 | return 0; | |
1494 | ||
1495 | data_start(i, &idx, &off); | |
1496 | /* some of this one + all after this one */ | |
1497 | npages = ((pipe->curbuf - idx - 1) & (pipe->buffers - 1)) + 1; | |
1498 | if (npages >= maxpages) | |
1499 | return maxpages; | |
1500 | } else iterate_all_kinds(i, size, v, ({ | |
e0f2dc40 AV |
1501 | unsigned long p = (unsigned long)v.iov_base; |
1502 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
1503 | - p / PAGE_SIZE; | |
1504 | if (npages >= maxpages) | |
1505 | return maxpages; | |
1506 | 0;}),({ | |
1507 | npages++; | |
1508 | if (npages >= maxpages) | |
1509 | return maxpages; | |
a280455f AV |
1510 | }),({ |
1511 | unsigned long p = (unsigned long)v.iov_base; | |
1512 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
1513 | - p / PAGE_SIZE; | |
1514 | if (npages >= maxpages) | |
1515 | return maxpages; | |
e0f2dc40 AV |
1516 | }) |
1517 | ) | |
1518 | return npages; | |
62a8067a | 1519 | } |
f67da30c | 1520 | EXPORT_SYMBOL(iov_iter_npages); |
4b8164b9 AV |
1521 | |
1522 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) | |
1523 | { | |
1524 | *new = *old; | |
00e23707 | 1525 | if (unlikely(iov_iter_is_pipe(new))) { |
241699cd AV |
1526 | WARN_ON(1); |
1527 | return NULL; | |
1528 | } | |
9ea9ce04 DH |
1529 | if (unlikely(iov_iter_is_discard(new))) |
1530 | return NULL; | |
00e23707 | 1531 | if (iov_iter_is_bvec(new)) |
4b8164b9 AV |
1532 | return new->bvec = kmemdup(new->bvec, |
1533 | new->nr_segs * sizeof(struct bio_vec), | |
1534 | flags); | |
1535 | else | |
1536 | /* iovec and kvec have identical layout */ | |
1537 | return new->iov = kmemdup(new->iov, | |
1538 | new->nr_segs * sizeof(struct iovec), | |
1539 | flags); | |
1540 | } | |
1541 | EXPORT_SYMBOL(dup_iter); | |
bc917be8 | 1542 | |
ffecee4f VN |
1543 | /** |
1544 | * import_iovec() - Copy an array of &struct iovec from userspace | |
1545 | * into the kernel, check that it is valid, and initialize a new | |
1546 | * &struct iov_iter iterator to access it. | |
1547 | * | |
1548 | * @type: One of %READ or %WRITE. | |
1549 | * @uvector: Pointer to the userspace array. | |
1550 | * @nr_segs: Number of elements in userspace array. | |
1551 | * @fast_segs: Number of elements in @iov. | |
1552 | * @iov: (input and output parameter) Pointer to pointer to (usually small | |
1553 | * on-stack) kernel array. | |
1554 | * @i: Pointer to iterator that will be initialized on success. | |
1555 | * | |
1556 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, | |
1557 | * then this function places %NULL in *@iov on return. Otherwise, a new | |
1558 | * array will be allocated and the result placed in *@iov. This means that | |
1559 | * the caller may call kfree() on *@iov regardless of whether the small | |
1560 | * on-stack array was used or not (and regardless of whether this function | |
1561 | * returns an error or not). | |
1562 | * | |
1563 | * Return: 0 on success or negative error code on error. | |
1564 | */ | |
bc917be8 AV |
1565 | int import_iovec(int type, const struct iovec __user * uvector, |
1566 | unsigned nr_segs, unsigned fast_segs, | |
1567 | struct iovec **iov, struct iov_iter *i) | |
1568 | { | |
1569 | ssize_t n; | |
1570 | struct iovec *p; | |
1571 | n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs, | |
1572 | *iov, &p); | |
1573 | if (n < 0) { | |
1574 | if (p != *iov) | |
1575 | kfree(p); | |
1576 | *iov = NULL; | |
1577 | return n; | |
1578 | } | |
1579 | iov_iter_init(i, type, p, nr_segs, n); | |
1580 | *iov = p == *iov ? NULL : p; | |
1581 | return 0; | |
1582 | } | |
1583 | EXPORT_SYMBOL(import_iovec); | |
1584 | ||
1585 | #ifdef CONFIG_COMPAT | |
1586 | #include <linux/compat.h> | |
1587 | ||
1588 | int compat_import_iovec(int type, const struct compat_iovec __user * uvector, | |
1589 | unsigned nr_segs, unsigned fast_segs, | |
1590 | struct iovec **iov, struct iov_iter *i) | |
1591 | { | |
1592 | ssize_t n; | |
1593 | struct iovec *p; | |
1594 | n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs, | |
1595 | *iov, &p); | |
1596 | if (n < 0) { | |
1597 | if (p != *iov) | |
1598 | kfree(p); | |
1599 | *iov = NULL; | |
1600 | return n; | |
1601 | } | |
1602 | iov_iter_init(i, type, p, nr_segs, n); | |
1603 | *iov = p == *iov ? NULL : p; | |
1604 | return 0; | |
1605 | } | |
1606 | #endif | |
1607 | ||
1608 | int import_single_range(int rw, void __user *buf, size_t len, | |
1609 | struct iovec *iov, struct iov_iter *i) | |
1610 | { | |
1611 | if (len > MAX_RW_COUNT) | |
1612 | len = MAX_RW_COUNT; | |
1613 | if (unlikely(!access_ok(!rw, buf, len))) | |
1614 | return -EFAULT; | |
1615 | ||
1616 | iov->iov_base = buf; | |
1617 | iov->iov_len = len; | |
1618 | iov_iter_init(i, rw, iov, 1, len); | |
1619 | return 0; | |
1620 | } | |
e1267585 | 1621 | EXPORT_SYMBOL(import_single_range); |
09cf698a AV |
1622 | |
1623 | int iov_iter_for_each_range(struct iov_iter *i, size_t bytes, | |
1624 | int (*f)(struct kvec *vec, void *context), | |
1625 | void *context) | |
1626 | { | |
1627 | struct kvec w; | |
1628 | int err = -EINVAL; | |
1629 | if (!bytes) | |
1630 | return 0; | |
1631 | ||
1632 | iterate_all_kinds(i, bytes, v, -EINVAL, ({ | |
1633 | w.iov_base = kmap(v.bv_page) + v.bv_offset; | |
1634 | w.iov_len = v.bv_len; | |
1635 | err = f(&w, context); | |
1636 | kunmap(v.bv_page); | |
1637 | err;}), ({ | |
1638 | w = v; | |
1639 | err = f(&w, context);}) | |
1640 | ) | |
1641 | return err; | |
1642 | } | |
1643 | EXPORT_SYMBOL(iov_iter_for_each_range); |