blob: a75ea633b5c46e42dfe6758011ad5c9665c3fd31
1 | #include <linux/export.h> |
2 | #include <linux/uio.h> |
3 | #include <linux/pagemap.h> |
4 | #include <linux/slab.h> |
5 | #include <linux/vmalloc.h> |
6 | #include <linux/splice.h> |
7 | #include <net/checksum.h> |
8 | |
9 | #define PIPE_PARANOIA /* for now */ |
10 | |
11 | #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ |
12 | size_t left; \ |
13 | size_t wanted = n; \ |
14 | __p = i->iov; \ |
15 | __v.iov_len = min(n, __p->iov_len - skip); \ |
16 | if (likely(__v.iov_len)) { \ |
17 | __v.iov_base = __p->iov_base + skip; \ |
18 | left = (STEP); \ |
19 | __v.iov_len -= left; \ |
20 | skip += __v.iov_len; \ |
21 | n -= __v.iov_len; \ |
22 | } else { \ |
23 | left = 0; \ |
24 | } \ |
25 | while (unlikely(!left && n)) { \ |
26 | __p++; \ |
27 | __v.iov_len = min(n, __p->iov_len); \ |
28 | if (unlikely(!__v.iov_len)) \ |
29 | continue; \ |
30 | __v.iov_base = __p->iov_base; \ |
31 | left = (STEP); \ |
32 | __v.iov_len -= left; \ |
33 | skip = __v.iov_len; \ |
34 | n -= __v.iov_len; \ |
35 | } \ |
36 | n = wanted - n; \ |
37 | } |
38 | |
39 | #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ |
40 | size_t wanted = n; \ |
41 | __p = i->kvec; \ |
42 | __v.iov_len = min(n, __p->iov_len - skip); \ |
43 | if (likely(__v.iov_len)) { \ |
44 | __v.iov_base = __p->iov_base + skip; \ |
45 | (void)(STEP); \ |
46 | skip += __v.iov_len; \ |
47 | n -= __v.iov_len; \ |
48 | } \ |
49 | while (unlikely(n)) { \ |
50 | __p++; \ |
51 | __v.iov_len = min(n, __p->iov_len); \ |
52 | if (unlikely(!__v.iov_len)) \ |
53 | continue; \ |
54 | __v.iov_base = __p->iov_base; \ |
55 | (void)(STEP); \ |
56 | skip = __v.iov_len; \ |
57 | n -= __v.iov_len; \ |
58 | } \ |
59 | n = wanted; \ |
60 | } |
61 | |
62 | #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ |
63 | struct bvec_iter __start; \ |
64 | __start.bi_size = n; \ |
65 | __start.bi_bvec_done = skip; \ |
66 | __start.bi_idx = 0; \ |
67 | for_each_bvec(__v, i->bvec, __bi, __start) { \ |
68 | if (!__v.bv_len) \ |
69 | continue; \ |
70 | (void)(STEP); \ |
71 | } \ |
72 | } |
73 | |
74 | #define iterate_all_kinds(i, n, v, I, B, K) { \ |
75 | size_t skip = i->iov_offset; \ |
76 | if (unlikely(i->type & ITER_BVEC)) { \ |
77 | struct bio_vec v; \ |
78 | struct bvec_iter __bi; \ |
79 | iterate_bvec(i, n, v, __bi, skip, (B)) \ |
80 | } else if (unlikely(i->type & ITER_KVEC)) { \ |
81 | const struct kvec *kvec; \ |
82 | struct kvec v; \ |
83 | iterate_kvec(i, n, v, kvec, skip, (K)) \ |
84 | } else { \ |
85 | const struct iovec *iov; \ |
86 | struct iovec v; \ |
87 | iterate_iovec(i, n, v, iov, skip, (I)) \ |
88 | } \ |
89 | } |
90 | |
91 | #define iterate_and_advance(i, n, v, I, B, K) { \ |
92 | if (unlikely(i->count < n)) \ |
93 | n = i->count; \ |
94 | if (i->count) { \ |
95 | size_t skip = i->iov_offset; \ |
96 | if (unlikely(i->type & ITER_BVEC)) { \ |
97 | const struct bio_vec *bvec = i->bvec; \ |
98 | struct bio_vec v; \ |
99 | struct bvec_iter __bi; \ |
100 | iterate_bvec(i, n, v, __bi, skip, (B)) \ |
101 | i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ |
102 | i->nr_segs -= i->bvec - bvec; \ |
103 | skip = __bi.bi_bvec_done; \ |
104 | } else if (unlikely(i->type & ITER_KVEC)) { \ |
105 | const struct kvec *kvec; \ |
106 | struct kvec v; \ |
107 | iterate_kvec(i, n, v, kvec, skip, (K)) \ |
108 | if (skip == kvec->iov_len) { \ |
109 | kvec++; \ |
110 | skip = 0; \ |
111 | } \ |
112 | i->nr_segs -= kvec - i->kvec; \ |
113 | i->kvec = kvec; \ |
114 | } else { \ |
115 | const struct iovec *iov; \ |
116 | struct iovec v; \ |
117 | iterate_iovec(i, n, v, iov, skip, (I)) \ |
118 | if (skip == iov->iov_len) { \ |
119 | iov++; \ |
120 | skip = 0; \ |
121 | } \ |
122 | i->nr_segs -= iov - i->iov; \ |
123 | i->iov = iov; \ |
124 | } \ |
125 | i->count -= n; \ |
126 | i->iov_offset = skip; \ |
127 | } \ |
128 | } |
129 | |
130 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
131 | struct iov_iter *i) |
132 | { |
133 | size_t skip, copy, left, wanted; |
134 | const struct iovec *iov; |
135 | char __user *buf; |
136 | void *kaddr, *from; |
137 | |
138 | if (unlikely(bytes > i->count)) |
139 | bytes = i->count; |
140 | |
141 | if (unlikely(!bytes)) |
142 | return 0; |
143 | |
144 | wanted = bytes; |
145 | iov = i->iov; |
146 | skip = i->iov_offset; |
147 | buf = iov->iov_base + skip; |
148 | copy = min(bytes, iov->iov_len - skip); |
149 | |
150 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { |
151 | kaddr = kmap_atomic(page); |
152 | from = kaddr + offset; |
153 | |
154 | /* first chunk, usually the only one */ |
155 | left = __copy_to_user_inatomic(buf, from, copy); |
156 | copy -= left; |
157 | skip += copy; |
158 | from += copy; |
159 | bytes -= copy; |
160 | |
161 | while (unlikely(!left && bytes)) { |
162 | iov++; |
163 | buf = iov->iov_base; |
164 | copy = min(bytes, iov->iov_len); |
165 | left = __copy_to_user_inatomic(buf, from, copy); |
166 | copy -= left; |
167 | skip = copy; |
168 | from += copy; |
169 | bytes -= copy; |
170 | } |
171 | if (likely(!bytes)) { |
172 | kunmap_atomic(kaddr); |
173 | goto done; |
174 | } |
175 | offset = from - kaddr; |
176 | buf += copy; |
177 | kunmap_atomic(kaddr); |
178 | copy = min(bytes, iov->iov_len - skip); |
179 | } |
180 | /* Too bad - revert to non-atomic kmap */ |
181 | |
182 | kaddr = kmap(page); |
183 | from = kaddr + offset; |
184 | left = __copy_to_user(buf, from, copy); |
185 | copy -= left; |
186 | skip += copy; |
187 | from += copy; |
188 | bytes -= copy; |
189 | while (unlikely(!left && bytes)) { |
190 | iov++; |
191 | buf = iov->iov_base; |
192 | copy = min(bytes, iov->iov_len); |
193 | left = __copy_to_user(buf, from, copy); |
194 | copy -= left; |
195 | skip = copy; |
196 | from += copy; |
197 | bytes -= copy; |
198 | } |
199 | kunmap(page); |
200 | |
201 | done: |
202 | if (skip == iov->iov_len) { |
203 | iov++; |
204 | skip = 0; |
205 | } |
206 | i->count -= wanted - bytes; |
207 | i->nr_segs -= iov - i->iov; |
208 | i->iov = iov; |
209 | i->iov_offset = skip; |
210 | return wanted - bytes; |
211 | } |
212 | |
213 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
214 | struct iov_iter *i) |
215 | { |
216 | size_t skip, copy, left, wanted; |
217 | const struct iovec *iov; |
218 | char __user *buf; |
219 | void *kaddr, *to; |
220 | |
221 | if (unlikely(bytes > i->count)) |
222 | bytes = i->count; |
223 | |
224 | if (unlikely(!bytes)) |
225 | return 0; |
226 | |
227 | wanted = bytes; |
228 | iov = i->iov; |
229 | skip = i->iov_offset; |
230 | buf = iov->iov_base + skip; |
231 | copy = min(bytes, iov->iov_len - skip); |
232 | |
233 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { |
234 | kaddr = kmap_atomic(page); |
235 | to = kaddr + offset; |
236 | |
237 | /* first chunk, usually the only one */ |
238 | left = __copy_from_user_inatomic(to, buf, copy); |
239 | copy -= left; |
240 | skip += copy; |
241 | to += copy; |
242 | bytes -= copy; |
243 | |
244 | while (unlikely(!left && bytes)) { |
245 | iov++; |
246 | buf = iov->iov_base; |
247 | copy = min(bytes, iov->iov_len); |
248 | left = __copy_from_user_inatomic(to, buf, copy); |
249 | copy -= left; |
250 | skip = copy; |
251 | to += copy; |
252 | bytes -= copy; |
253 | } |
254 | if (likely(!bytes)) { |
255 | kunmap_atomic(kaddr); |
256 | goto done; |
257 | } |
258 | offset = to - kaddr; |
259 | buf += copy; |
260 | kunmap_atomic(kaddr); |
261 | copy = min(bytes, iov->iov_len - skip); |
262 | } |
263 | /* Too bad - revert to non-atomic kmap */ |
264 | |
265 | kaddr = kmap(page); |
266 | to = kaddr + offset; |
267 | left = __copy_from_user(to, buf, copy); |
268 | copy -= left; |
269 | skip += copy; |
270 | to += copy; |
271 | bytes -= copy; |
272 | while (unlikely(!left && bytes)) { |
273 | iov++; |
274 | buf = iov->iov_base; |
275 | copy = min(bytes, iov->iov_len); |
276 | left = __copy_from_user(to, buf, copy); |
277 | copy -= left; |
278 | skip = copy; |
279 | to += copy; |
280 | bytes -= copy; |
281 | } |
282 | kunmap(page); |
283 | |
284 | done: |
285 | if (skip == iov->iov_len) { |
286 | iov++; |
287 | skip = 0; |
288 | } |
289 | i->count -= wanted - bytes; |
290 | i->nr_segs -= iov - i->iov; |
291 | i->iov = iov; |
292 | i->iov_offset = skip; |
293 | return wanted - bytes; |
294 | } |
295 | |
296 | #ifdef PIPE_PARANOIA |
297 | static bool sanity(const struct iov_iter *i) |
298 | { |
299 | struct pipe_inode_info *pipe = i->pipe; |
300 | int idx = i->idx; |
301 | int next = pipe->curbuf + pipe->nrbufs; |
302 | if (i->iov_offset) { |
303 | struct pipe_buffer *p; |
304 | if (unlikely(!pipe->nrbufs)) |
305 | goto Bad; // pipe must be non-empty |
306 | if (unlikely(idx != ((next - 1) & (pipe->buffers - 1)))) |
307 | goto Bad; // must be at the last buffer... |
308 | |
309 | p = &pipe->bufs[idx]; |
310 | if (unlikely(p->offset + p->len != i->iov_offset)) |
311 | goto Bad; // ... at the end of segment |
312 | } else { |
313 | if (idx != (next & (pipe->buffers - 1))) |
314 | goto Bad; // must be right after the last buffer |
315 | } |
316 | return true; |
317 | Bad: |
318 | printk(KERN_ERR "idx = %d, offset = %zd\n", i->idx, i->iov_offset); |
319 | printk(KERN_ERR "curbuf = %d, nrbufs = %d, buffers = %d\n", |
320 | pipe->curbuf, pipe->nrbufs, pipe->buffers); |
321 | for (idx = 0; idx < pipe->buffers; idx++) |
322 | printk(KERN_ERR "[%p %p %d %d]\n", |
323 | pipe->bufs[idx].ops, |
324 | pipe->bufs[idx].page, |
325 | pipe->bufs[idx].offset, |
326 | pipe->bufs[idx].len); |
327 | WARN_ON(1); |
328 | return false; |
329 | } |
330 | #else |
331 | #define sanity(i) true |
332 | #endif |
333 | |
334 | static inline int next_idx(int idx, struct pipe_inode_info *pipe) |
335 | { |
336 | return (idx + 1) & (pipe->buffers - 1); |
337 | } |
338 | |
339 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
340 | struct iov_iter *i) |
341 | { |
342 | struct pipe_inode_info *pipe = i->pipe; |
343 | struct pipe_buffer *buf; |
344 | size_t off; |
345 | int idx; |
346 | |
347 | if (unlikely(bytes > i->count)) |
348 | bytes = i->count; |
349 | |
350 | if (unlikely(!bytes)) |
351 | return 0; |
352 | |
353 | if (!sanity(i)) |
354 | return 0; |
355 | |
356 | off = i->iov_offset; |
357 | idx = i->idx; |
358 | buf = &pipe->bufs[idx]; |
359 | if (off) { |
360 | if (offset == off && buf->page == page) { |
361 | /* merge with the last one */ |
362 | buf->len += bytes; |
363 | i->iov_offset += bytes; |
364 | goto out; |
365 | } |
366 | idx = next_idx(idx, pipe); |
367 | buf = &pipe->bufs[idx]; |
368 | } |
369 | if (idx == pipe->curbuf && pipe->nrbufs) |
370 | return 0; |
371 | pipe->nrbufs++; |
372 | buf->ops = &page_cache_pipe_buf_ops; |
373 | get_page(buf->page = page); |
374 | buf->offset = offset; |
375 | buf->len = bytes; |
376 | i->iov_offset = offset + bytes; |
377 | i->idx = idx; |
378 | out: |
379 | i->count -= bytes; |
380 | return bytes; |
381 | } |
382 | |
383 | /* |
384 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of |
385 | * bytes. For each iovec, fault in each page that constitutes the iovec. |
386 | * |
387 | * Return 0 on success, or non-zero if the memory could not be accessed (i.e. |
388 | * because it is an invalid address). |
389 | */ |
390 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) |
391 | { |
392 | size_t skip = i->iov_offset; |
393 | const struct iovec *iov; |
394 | int err; |
395 | struct iovec v; |
396 | |
397 | if (!(i->type & (ITER_BVEC|ITER_KVEC))) { |
398 | iterate_iovec(i, bytes, v, iov, skip, ({ |
399 | err = fault_in_pages_readable(v.iov_base, v.iov_len); |
400 | if (unlikely(err)) |
401 | return err; |
402 | 0;})) |
403 | } |
404 | return 0; |
405 | } |
406 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
407 | |
408 | void iov_iter_init(struct iov_iter *i, int direction, |
409 | const struct iovec *iov, unsigned long nr_segs, |
410 | size_t count) |
411 | { |
412 | /* It will get better. Eventually... */ |
413 | if (segment_eq(get_fs(), KERNEL_DS)) { |
414 | direction |= ITER_KVEC; |
415 | i->type = direction; |
416 | i->kvec = (struct kvec *)iov; |
417 | } else { |
418 | i->type = direction; |
419 | i->iov = iov; |
420 | } |
421 | i->nr_segs = nr_segs; |
422 | i->iov_offset = 0; |
423 | i->count = count; |
424 | } |
425 | EXPORT_SYMBOL(iov_iter_init); |
426 | |
427 | static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len) |
428 | { |
429 | char *from = kmap_atomic(page); |
430 | memcpy(to, from + offset, len); |
431 | kunmap_atomic(from); |
432 | } |
433 | |
434 | static void memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len) |
435 | { |
436 | char *to = kmap_atomic(page); |
437 | memcpy(to + offset, from, len); |
438 | kunmap_atomic(to); |
439 | } |
440 | |
441 | static void memzero_page(struct page *page, size_t offset, size_t len) |
442 | { |
443 | char *addr = kmap_atomic(page); |
444 | memset(addr + offset, 0, len); |
445 | kunmap_atomic(addr); |
446 | } |
447 | |
448 | static inline bool allocated(struct pipe_buffer *buf) |
449 | { |
450 | return buf->ops == &default_pipe_buf_ops; |
451 | } |
452 | |
453 | static inline void data_start(const struct iov_iter *i, int *idxp, size_t *offp) |
454 | { |
455 | size_t off = i->iov_offset; |
456 | int idx = i->idx; |
457 | if (off && (!allocated(&i->pipe->bufs[idx]) || off == PAGE_SIZE)) { |
458 | idx = next_idx(idx, i->pipe); |
459 | off = 0; |
460 | } |
461 | *idxp = idx; |
462 | *offp = off; |
463 | } |
464 | |
465 | static size_t push_pipe(struct iov_iter *i, size_t size, |
466 | int *idxp, size_t *offp) |
467 | { |
468 | struct pipe_inode_info *pipe = i->pipe; |
469 | size_t off; |
470 | int idx; |
471 | ssize_t left; |
472 | |
473 | if (unlikely(size > i->count)) |
474 | size = i->count; |
475 | if (unlikely(!size)) |
476 | return 0; |
477 | |
478 | left = size; |
479 | data_start(i, &idx, &off); |
480 | *idxp = idx; |
481 | *offp = off; |
482 | if (off) { |
483 | left -= PAGE_SIZE - off; |
484 | if (left <= 0) { |
485 | pipe->bufs[idx].len += size; |
486 | return size; |
487 | } |
488 | pipe->bufs[idx].len = PAGE_SIZE; |
489 | idx = next_idx(idx, pipe); |
490 | } |
491 | while (idx != pipe->curbuf || !pipe->nrbufs) { |
492 | struct page *page = alloc_page(GFP_USER); |
493 | if (!page) |
494 | break; |
495 | pipe->nrbufs++; |
496 | pipe->bufs[idx].ops = &default_pipe_buf_ops; |
497 | pipe->bufs[idx].page = page; |
498 | pipe->bufs[idx].offset = 0; |
499 | if (left <= PAGE_SIZE) { |
500 | pipe->bufs[idx].len = left; |
501 | return size; |
502 | } |
503 | pipe->bufs[idx].len = PAGE_SIZE; |
504 | left -= PAGE_SIZE; |
505 | idx = next_idx(idx, pipe); |
506 | } |
507 | return size - left; |
508 | } |
509 | |
510 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, |
511 | struct iov_iter *i) |
512 | { |
513 | struct pipe_inode_info *pipe = i->pipe; |
514 | size_t n, off; |
515 | int idx; |
516 | |
517 | if (!sanity(i)) |
518 | return 0; |
519 | |
520 | bytes = n = push_pipe(i, bytes, &idx, &off); |
521 | if (unlikely(!n)) |
522 | return 0; |
523 | for ( ; n; idx = next_idx(idx, pipe), off = 0) { |
524 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
525 | memcpy_to_page(pipe->bufs[idx].page, off, addr, chunk); |
526 | i->idx = idx; |
527 | i->iov_offset = off + chunk; |
528 | n -= chunk; |
529 | addr += chunk; |
530 | } |
531 | i->count -= bytes; |
532 | return bytes; |
533 | } |
534 | |
535 | size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
536 | { |
537 | const char *from = addr; |
538 | if (unlikely(i->type & ITER_PIPE)) |
539 | return copy_pipe_to_iter(addr, bytes, i); |
540 | iterate_and_advance(i, bytes, v, |
541 | __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len, |
542 | v.iov_len), |
543 | memcpy_to_page(v.bv_page, v.bv_offset, |
544 | (from += v.bv_len) - v.bv_len, v.bv_len), |
545 | memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len) |
546 | ) |
547 | |
548 | return bytes; |
549 | } |
550 | EXPORT_SYMBOL(copy_to_iter); |
551 | |
552 | size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
553 | { |
554 | char *to = addr; |
555 | if (unlikely(i->type & ITER_PIPE)) { |
556 | WARN_ON(1); |
557 | return 0; |
558 | } |
559 | iterate_and_advance(i, bytes, v, |
560 | __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base, |
561 | v.iov_len), |
562 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
563 | v.bv_offset, v.bv_len), |
564 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
565 | ) |
566 | |
567 | return bytes; |
568 | } |
569 | EXPORT_SYMBOL(copy_from_iter); |
570 | |
571 | size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
572 | { |
573 | char *to = addr; |
574 | if (unlikely(i->type & ITER_PIPE)) { |
575 | WARN_ON(1); |
576 | return 0; |
577 | } |
578 | iterate_and_advance(i, bytes, v, |
579 | __copy_from_user_nocache((to += v.iov_len) - v.iov_len, |
580 | v.iov_base, v.iov_len), |
581 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
582 | v.bv_offset, v.bv_len), |
583 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
584 | ) |
585 | |
586 | return bytes; |
587 | } |
588 | EXPORT_SYMBOL(copy_from_iter_nocache); |
589 | |
590 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
591 | struct iov_iter *i) |
592 | { |
593 | if (i->type & (ITER_BVEC|ITER_KVEC)) { |
594 | void *kaddr = kmap_atomic(page); |
595 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); |
596 | kunmap_atomic(kaddr); |
597 | return wanted; |
598 | } else if (likely(!(i->type & ITER_PIPE))) |
599 | return copy_page_to_iter_iovec(page, offset, bytes, i); |
600 | else |
601 | return copy_page_to_iter_pipe(page, offset, bytes, i); |
602 | } |
603 | EXPORT_SYMBOL(copy_page_to_iter); |
604 | |
605 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
606 | struct iov_iter *i) |
607 | { |
608 | if (unlikely(i->type & ITER_PIPE)) { |
609 | WARN_ON(1); |
610 | return 0; |
611 | } |
612 | if (i->type & (ITER_BVEC|ITER_KVEC)) { |
613 | void *kaddr = kmap_atomic(page); |
614 | size_t wanted = copy_from_iter(kaddr + offset, bytes, i); |
615 | kunmap_atomic(kaddr); |
616 | return wanted; |
617 | } else |
618 | return copy_page_from_iter_iovec(page, offset, bytes, i); |
619 | } |
620 | EXPORT_SYMBOL(copy_page_from_iter); |
621 | |
622 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
623 | { |
624 | struct pipe_inode_info *pipe = i->pipe; |
625 | size_t n, off; |
626 | int idx; |
627 | |
628 | if (!sanity(i)) |
629 | return 0; |
630 | |
631 | bytes = n = push_pipe(i, bytes, &idx, &off); |
632 | if (unlikely(!n)) |
633 | return 0; |
634 | |
635 | for ( ; n; idx = next_idx(idx, pipe), off = 0) { |
636 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
637 | memzero_page(pipe->bufs[idx].page, off, chunk); |
638 | i->idx = idx; |
639 | i->iov_offset = off + chunk; |
640 | n -= chunk; |
641 | } |
642 | i->count -= bytes; |
643 | return bytes; |
644 | } |
645 | |
646 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
647 | { |
648 | if (unlikely(i->type & ITER_PIPE)) |
649 | return pipe_zero(bytes, i); |
650 | iterate_and_advance(i, bytes, v, |
651 | __clear_user(v.iov_base, v.iov_len), |
652 | memzero_page(v.bv_page, v.bv_offset, v.bv_len), |
653 | memset(v.iov_base, 0, v.iov_len) |
654 | ) |
655 | |
656 | return bytes; |
657 | } |
658 | EXPORT_SYMBOL(iov_iter_zero); |
659 | |
660 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
661 | struct iov_iter *i, unsigned long offset, size_t bytes) |
662 | { |
663 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
664 | if (unlikely(i->type & ITER_PIPE)) { |
665 | kunmap_atomic(kaddr); |
666 | WARN_ON(1); |
667 | return 0; |
668 | } |
669 | iterate_all_kinds(i, bytes, v, |
670 | __copy_from_user_inatomic((p += v.iov_len) - v.iov_len, |
671 | v.iov_base, v.iov_len), |
672 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, |
673 | v.bv_offset, v.bv_len), |
674 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
675 | ) |
676 | kunmap_atomic(kaddr); |
677 | return bytes; |
678 | } |
679 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); |
680 | |
681 | static inline void pipe_truncate(struct iov_iter *i) |
682 | { |
683 | struct pipe_inode_info *pipe = i->pipe; |
684 | if (pipe->nrbufs) { |
685 | size_t off = i->iov_offset; |
686 | int idx = i->idx; |
687 | int nrbufs = (idx - pipe->curbuf) & (pipe->buffers - 1); |
688 | if (off) { |
689 | pipe->bufs[idx].len = off - pipe->bufs[idx].offset; |
690 | idx = next_idx(idx, pipe); |
691 | nrbufs++; |
692 | } |
693 | while (pipe->nrbufs > nrbufs) { |
694 | pipe_buf_release(pipe, &pipe->bufs[idx]); |
695 | idx = next_idx(idx, pipe); |
696 | pipe->nrbufs--; |
697 | } |
698 | } |
699 | } |
700 | |
701 | static void pipe_advance(struct iov_iter *i, size_t size) |
702 | { |
703 | struct pipe_inode_info *pipe = i->pipe; |
704 | if (unlikely(i->count < size)) |
705 | size = i->count; |
706 | if (size) { |
707 | struct pipe_buffer *buf; |
708 | size_t off = i->iov_offset, left = size; |
709 | int idx = i->idx; |
710 | if (off) /* make it relative to the beginning of buffer */ |
711 | left += off - pipe->bufs[idx].offset; |
712 | while (1) { |
713 | buf = &pipe->bufs[idx]; |
714 | if (left <= buf->len) |
715 | break; |
716 | left -= buf->len; |
717 | idx = next_idx(idx, pipe); |
718 | } |
719 | i->idx = idx; |
720 | i->iov_offset = buf->offset + left; |
721 | } |
722 | i->count -= size; |
723 | /* ... and discard everything past that point */ |
724 | pipe_truncate(i); |
725 | } |
726 | |
727 | void iov_iter_advance(struct iov_iter *i, size_t size) |
728 | { |
729 | if (unlikely(i->type & ITER_PIPE)) { |
730 | pipe_advance(i, size); |
731 | return; |
732 | } |
733 | iterate_and_advance(i, size, v, 0, 0, 0) |
734 | } |
735 | EXPORT_SYMBOL(iov_iter_advance); |
736 | |
737 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
738 | { |
739 | if (!unroll) |
740 | return; |
741 | i->count += unroll; |
742 | if (unlikely(i->type & ITER_PIPE)) { |
743 | struct pipe_inode_info *pipe = i->pipe; |
744 | int idx = i->idx; |
745 | size_t off = i->iov_offset; |
746 | while (1) { |
747 | size_t n = off - pipe->bufs[idx].offset; |
748 | if (unroll < n) { |
749 | off -= (n - unroll); |
750 | break; |
751 | } |
752 | unroll -= n; |
753 | if (!unroll && idx == i->start_idx) { |
754 | off = 0; |
755 | break; |
756 | } |
757 | if (!idx--) |
758 | idx = pipe->buffers - 1; |
759 | off = pipe->bufs[idx].offset + pipe->bufs[idx].len; |
760 | } |
761 | i->iov_offset = off; |
762 | i->idx = idx; |
763 | pipe_truncate(i); |
764 | return; |
765 | } |
766 | if (unroll <= i->iov_offset) { |
767 | i->iov_offset -= unroll; |
768 | return; |
769 | } |
770 | unroll -= i->iov_offset; |
771 | if (i->type & ITER_BVEC) { |
772 | const struct bio_vec *bvec = i->bvec; |
773 | while (1) { |
774 | size_t n = (--bvec)->bv_len; |
775 | i->nr_segs++; |
776 | if (unroll <= n) { |
777 | i->bvec = bvec; |
778 | i->iov_offset = n - unroll; |
779 | return; |
780 | } |
781 | unroll -= n; |
782 | } |
783 | } else { /* same logics for iovec and kvec */ |
784 | const struct iovec *iov = i->iov; |
785 | while (1) { |
786 | size_t n = (--iov)->iov_len; |
787 | i->nr_segs++; |
788 | if (unroll <= n) { |
789 | i->iov = iov; |
790 | i->iov_offset = n - unroll; |
791 | return; |
792 | } |
793 | unroll -= n; |
794 | } |
795 | } |
796 | } |
797 | EXPORT_SYMBOL(iov_iter_revert); |
798 | |
799 | /* |
800 | * Return the count of just the current iov_iter segment. |
801 | */ |
802 | size_t iov_iter_single_seg_count(const struct iov_iter *i) |
803 | { |
804 | if (unlikely(i->type & ITER_PIPE)) |
805 | return i->count; // it is a silly place, anyway |
806 | if (i->nr_segs == 1) |
807 | return i->count; |
808 | else if (i->type & ITER_BVEC) |
809 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
810 | else |
811 | return min(i->count, i->iov->iov_len - i->iov_offset); |
812 | } |
813 | EXPORT_SYMBOL(iov_iter_single_seg_count); |
814 | |
815 | void iov_iter_kvec(struct iov_iter *i, int direction, |
816 | const struct kvec *kvec, unsigned long nr_segs, |
817 | size_t count) |
818 | { |
819 | BUG_ON(!(direction & ITER_KVEC)); |
820 | i->type = direction; |
821 | i->kvec = kvec; |
822 | i->nr_segs = nr_segs; |
823 | i->iov_offset = 0; |
824 | i->count = count; |
825 | } |
826 | EXPORT_SYMBOL(iov_iter_kvec); |
827 | |
828 | void iov_iter_bvec(struct iov_iter *i, int direction, |
829 | const struct bio_vec *bvec, unsigned long nr_segs, |
830 | size_t count) |
831 | { |
832 | BUG_ON(!(direction & ITER_BVEC)); |
833 | i->type = direction; |
834 | i->bvec = bvec; |
835 | i->nr_segs = nr_segs; |
836 | i->iov_offset = 0; |
837 | i->count = count; |
838 | } |
839 | EXPORT_SYMBOL(iov_iter_bvec); |
840 | |
841 | void iov_iter_pipe(struct iov_iter *i, int direction, |
842 | struct pipe_inode_info *pipe, |
843 | size_t count) |
844 | { |
845 | BUG_ON(direction != ITER_PIPE); |
846 | WARN_ON(pipe->nrbufs == pipe->buffers); |
847 | i->type = direction; |
848 | i->pipe = pipe; |
849 | i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); |
850 | i->iov_offset = 0; |
851 | i->count = count; |
852 | i->start_idx = i->idx; |
853 | } |
854 | EXPORT_SYMBOL(iov_iter_pipe); |
855 | |
856 | unsigned long iov_iter_alignment(const struct iov_iter *i) |
857 | { |
858 | unsigned long res = 0; |
859 | size_t size = i->count; |
860 | |
861 | if (!size) |
862 | return 0; |
863 | |
864 | if (unlikely(i->type & ITER_PIPE)) { |
865 | if (i->iov_offset && allocated(&i->pipe->bufs[i->idx])) |
866 | return size | i->iov_offset; |
867 | return size; |
868 | } |
869 | iterate_all_kinds(i, size, v, |
870 | (res |= (unsigned long)v.iov_base | v.iov_len, 0), |
871 | res |= v.bv_offset | v.bv_len, |
872 | res |= (unsigned long)v.iov_base | v.iov_len |
873 | ) |
874 | return res; |
875 | } |
876 | EXPORT_SYMBOL(iov_iter_alignment); |
877 | |
878 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
879 | { |
880 | unsigned long res = 0; |
881 | size_t size = i->count; |
882 | if (!size) |
883 | return 0; |
884 | |
885 | if (unlikely(i->type & ITER_PIPE)) { |
886 | WARN_ON(1); |
887 | return ~0U; |
888 | } |
889 | |
890 | iterate_all_kinds(i, size, v, |
891 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | |
892 | (size != v.iov_len ? size : 0), 0), |
893 | (res |= (!res ? 0 : (unsigned long)v.bv_offset) | |
894 | (size != v.bv_len ? size : 0)), |
895 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | |
896 | (size != v.iov_len ? size : 0)) |
897 | ); |
898 | return res; |
899 | } |
900 | EXPORT_SYMBOL(iov_iter_gap_alignment); |
901 | |
902 | static inline size_t __pipe_get_pages(struct iov_iter *i, |
903 | size_t maxsize, |
904 | struct page **pages, |
905 | int idx, |
906 | size_t *start) |
907 | { |
908 | struct pipe_inode_info *pipe = i->pipe; |
909 | ssize_t n = push_pipe(i, maxsize, &idx, start); |
910 | if (!n) |
911 | return -EFAULT; |
912 | |
913 | maxsize = n; |
914 | n += *start; |
915 | while (n > 0) { |
916 | get_page(*pages++ = pipe->bufs[idx].page); |
917 | idx = next_idx(idx, pipe); |
918 | n -= PAGE_SIZE; |
919 | } |
920 | |
921 | return maxsize; |
922 | } |
923 | |
924 | static ssize_t pipe_get_pages(struct iov_iter *i, |
925 | struct page **pages, size_t maxsize, unsigned maxpages, |
926 | size_t *start) |
927 | { |
928 | unsigned npages; |
929 | size_t capacity; |
930 | int idx; |
931 | |
932 | if (!sanity(i)) |
933 | return -EFAULT; |
934 | |
935 | data_start(i, &idx, start); |
936 | /* some of this one + all after this one */ |
937 | npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1; |
938 | capacity = min(npages,maxpages) * PAGE_SIZE - *start; |
939 | |
940 | return __pipe_get_pages(i, min(maxsize, capacity), pages, idx, start); |
941 | } |
942 | |
943 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
944 | struct page **pages, size_t maxsize, unsigned maxpages, |
945 | size_t *start) |
946 | { |
947 | if (maxsize > i->count) |
948 | maxsize = i->count; |
949 | |
950 | if (!maxsize) |
951 | return 0; |
952 | |
953 | if (unlikely(i->type & ITER_PIPE)) |
954 | return pipe_get_pages(i, pages, maxsize, maxpages, start); |
955 | iterate_all_kinds(i, maxsize, v, ({ |
956 | unsigned long addr = (unsigned long)v.iov_base; |
957 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); |
958 | int n; |
959 | int res; |
960 | |
961 | if (len > maxpages * PAGE_SIZE) |
962 | len = maxpages * PAGE_SIZE; |
963 | addr &= ~(PAGE_SIZE - 1); |
964 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
965 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages); |
966 | if (unlikely(res < 0)) |
967 | return res; |
968 | return (res == n ? len : res * PAGE_SIZE) - *start; |
969 | 0;}),({ |
970 | /* can't be more than PAGE_SIZE */ |
971 | *start = v.bv_offset; |
972 | get_page(*pages = v.bv_page); |
973 | return v.bv_len; |
974 | }),({ |
975 | return -EFAULT; |
976 | }) |
977 | ) |
978 | return 0; |
979 | } |
980 | EXPORT_SYMBOL(iov_iter_get_pages); |
981 | |
982 | static struct page **get_pages_array(size_t n) |
983 | { |
984 | struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL); |
985 | if (!p) |
986 | p = vmalloc(n * sizeof(struct page *)); |
987 | return p; |
988 | } |
989 | |
990 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
991 | struct page ***pages, size_t maxsize, |
992 | size_t *start) |
993 | { |
994 | struct page **p; |
995 | size_t n; |
996 | int idx; |
997 | int npages; |
998 | |
999 | if (!sanity(i)) |
1000 | return -EFAULT; |
1001 | |
1002 | data_start(i, &idx, start); |
1003 | /* some of this one + all after this one */ |
1004 | npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1; |
1005 | n = npages * PAGE_SIZE - *start; |
1006 | if (maxsize > n) |
1007 | maxsize = n; |
1008 | else |
1009 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); |
1010 | p = get_pages_array(npages); |
1011 | if (!p) |
1012 | return -ENOMEM; |
1013 | n = __pipe_get_pages(i, maxsize, p, idx, start); |
1014 | if (n > 0) |
1015 | *pages = p; |
1016 | else |
1017 | kvfree(p); |
1018 | return n; |
1019 | } |
1020 | |
1021 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
1022 | struct page ***pages, size_t maxsize, |
1023 | size_t *start) |
1024 | { |
1025 | struct page **p; |
1026 | |
1027 | if (maxsize > i->count) |
1028 | maxsize = i->count; |
1029 | |
1030 | if (!maxsize) |
1031 | return 0; |
1032 | |
1033 | if (unlikely(i->type & ITER_PIPE)) |
1034 | return pipe_get_pages_alloc(i, pages, maxsize, start); |
1035 | iterate_all_kinds(i, maxsize, v, ({ |
1036 | unsigned long addr = (unsigned long)v.iov_base; |
1037 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); |
1038 | int n; |
1039 | int res; |
1040 | |
1041 | addr &= ~(PAGE_SIZE - 1); |
1042 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
1043 | p = get_pages_array(n); |
1044 | if (!p) |
1045 | return -ENOMEM; |
1046 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p); |
1047 | if (unlikely(res < 0)) { |
1048 | kvfree(p); |
1049 | return res; |
1050 | } |
1051 | *pages = p; |
1052 | return (res == n ? len : res * PAGE_SIZE) - *start; |
1053 | 0;}),({ |
1054 | /* can't be more than PAGE_SIZE */ |
1055 | *start = v.bv_offset; |
1056 | *pages = p = get_pages_array(1); |
1057 | if (!p) |
1058 | return -ENOMEM; |
1059 | get_page(*p = v.bv_page); |
1060 | return v.bv_len; |
1061 | }),({ |
1062 | return -EFAULT; |
1063 | }) |
1064 | ) |
1065 | return 0; |
1066 | } |
1067 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); |
1068 | |
1069 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
1070 | struct iov_iter *i) |
1071 | { |
1072 | char *to = addr; |
1073 | __wsum sum, next; |
1074 | size_t off = 0; |
1075 | sum = *csum; |
1076 | if (unlikely(i->type & ITER_PIPE)) { |
1077 | WARN_ON(1); |
1078 | return 0; |
1079 | } |
1080 | iterate_and_advance(i, bytes, v, ({ |
1081 | int err = 0; |
1082 | next = csum_and_copy_from_user(v.iov_base, |
1083 | (to += v.iov_len) - v.iov_len, |
1084 | v.iov_len, 0, &err); |
1085 | if (!err) { |
1086 | sum = csum_block_add(sum, next, off); |
1087 | off += v.iov_len; |
1088 | } |
1089 | err ? v.iov_len : 0; |
1090 | }), ({ |
1091 | char *p = kmap_atomic(v.bv_page); |
1092 | next = csum_partial_copy_nocheck(p + v.bv_offset, |
1093 | (to += v.bv_len) - v.bv_len, |
1094 | v.bv_len, 0); |
1095 | kunmap_atomic(p); |
1096 | sum = csum_block_add(sum, next, off); |
1097 | off += v.bv_len; |
1098 | }),({ |
1099 | next = csum_partial_copy_nocheck(v.iov_base, |
1100 | (to += v.iov_len) - v.iov_len, |
1101 | v.iov_len, 0); |
1102 | sum = csum_block_add(sum, next, off); |
1103 | off += v.iov_len; |
1104 | }) |
1105 | ) |
1106 | *csum = sum; |
1107 | return bytes; |
1108 | } |
1109 | EXPORT_SYMBOL(csum_and_copy_from_iter); |
1110 | |
1111 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, |
1112 | struct iov_iter *i) |
1113 | { |
1114 | const char *from = addr; |
1115 | __wsum sum, next; |
1116 | size_t off = 0; |
1117 | sum = *csum; |
1118 | if (unlikely(i->type & ITER_PIPE)) { |
1119 | WARN_ON(1); /* for now */ |
1120 | return 0; |
1121 | } |
1122 | iterate_and_advance(i, bytes, v, ({ |
1123 | int err = 0; |
1124 | next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, |
1125 | v.iov_base, |
1126 | v.iov_len, 0, &err); |
1127 | if (!err) { |
1128 | sum = csum_block_add(sum, next, off); |
1129 | off += v.iov_len; |
1130 | } |
1131 | err ? v.iov_len : 0; |
1132 | }), ({ |
1133 | char *p = kmap_atomic(v.bv_page); |
1134 | next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len, |
1135 | p + v.bv_offset, |
1136 | v.bv_len, 0); |
1137 | kunmap_atomic(p); |
1138 | sum = csum_block_add(sum, next, off); |
1139 | off += v.bv_len; |
1140 | }),({ |
1141 | next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len, |
1142 | v.iov_base, |
1143 | v.iov_len, 0); |
1144 | sum = csum_block_add(sum, next, off); |
1145 | off += v.iov_len; |
1146 | }) |
1147 | ) |
1148 | *csum = sum; |
1149 | return bytes; |
1150 | } |
1151 | EXPORT_SYMBOL(csum_and_copy_to_iter); |
1152 | |
1153 | int iov_iter_npages(const struct iov_iter *i, int maxpages) |
1154 | { |
1155 | size_t size = i->count; |
1156 | int npages = 0; |
1157 | |
1158 | if (!size) |
1159 | return 0; |
1160 | |
1161 | if (unlikely(i->type & ITER_PIPE)) { |
1162 | struct pipe_inode_info *pipe = i->pipe; |
1163 | size_t off; |
1164 | int idx; |
1165 | |
1166 | if (!sanity(i)) |
1167 | return 0; |
1168 | |
1169 | data_start(i, &idx, &off); |
1170 | /* some of this one + all after this one */ |
1171 | npages = ((pipe->curbuf - idx - 1) & (pipe->buffers - 1)) + 1; |
1172 | if (npages >= maxpages) |
1173 | return maxpages; |
1174 | } else iterate_all_kinds(i, size, v, ({ |
1175 | unsigned long p = (unsigned long)v.iov_base; |
1176 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) |
1177 | - p / PAGE_SIZE; |
1178 | if (npages >= maxpages) |
1179 | return maxpages; |
1180 | 0;}),({ |
1181 | npages++; |
1182 | if (npages >= maxpages) |
1183 | return maxpages; |
1184 | }),({ |
1185 | unsigned long p = (unsigned long)v.iov_base; |
1186 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) |
1187 | - p / PAGE_SIZE; |
1188 | if (npages >= maxpages) |
1189 | return maxpages; |
1190 | }) |
1191 | ) |
1192 | return npages; |
1193 | } |
1194 | EXPORT_SYMBOL(iov_iter_npages); |
1195 | |
1196 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) |
1197 | { |
1198 | *new = *old; |
1199 | if (unlikely(new->type & ITER_PIPE)) { |
1200 | WARN_ON(1); |
1201 | return NULL; |
1202 | } |
1203 | if (new->type & ITER_BVEC) |
1204 | return new->bvec = kmemdup(new->bvec, |
1205 | new->nr_segs * sizeof(struct bio_vec), |
1206 | flags); |
1207 | else |
1208 | /* iovec and kvec have identical layout */ |
1209 | return new->iov = kmemdup(new->iov, |
1210 | new->nr_segs * sizeof(struct iovec), |
1211 | flags); |
1212 | } |
1213 | EXPORT_SYMBOL(dup_iter); |
1214 | |
1215 | /** |
1216 | * import_iovec() - Copy an array of &struct iovec from userspace |
1217 | * into the kernel, check that it is valid, and initialize a new |
1218 | * &struct iov_iter iterator to access it. |
1219 | * |
1220 | * @type: One of %READ or %WRITE. |
1221 | * @uvector: Pointer to the userspace array. |
1222 | * @nr_segs: Number of elements in userspace array. |
1223 | * @fast_segs: Number of elements in @iov. |
1224 | * @iov: (input and output parameter) Pointer to pointer to (usually small |
1225 | * on-stack) kernel array. |
1226 | * @i: Pointer to iterator that will be initialized on success. |
1227 | * |
1228 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, |
1229 | * then this function places %NULL in *@iov on return. Otherwise, a new |
1230 | * array will be allocated and the result placed in *@iov. This means that |
1231 | * the caller may call kfree() on *@iov regardless of whether the small |
1232 | * on-stack array was used or not (and regardless of whether this function |
1233 | * returns an error or not). |
1234 | * |
1235 | * Return: 0 on success or negative error code on error. |
1236 | */ |
1237 | int import_iovec(int type, const struct iovec __user * uvector, |
1238 | unsigned nr_segs, unsigned fast_segs, |
1239 | struct iovec **iov, struct iov_iter *i) |
1240 | { |
1241 | ssize_t n; |
1242 | struct iovec *p; |
1243 | n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs, |
1244 | *iov, &p); |
1245 | if (n < 0) { |
1246 | if (p != *iov) |
1247 | kfree(p); |
1248 | *iov = NULL; |
1249 | return n; |
1250 | } |
1251 | iov_iter_init(i, type, p, nr_segs, n); |
1252 | *iov = p == *iov ? NULL : p; |
1253 | return 0; |
1254 | } |
1255 | EXPORT_SYMBOL(import_iovec); |
1256 | |
1257 | #ifdef CONFIG_COMPAT |
1258 | #include <linux/compat.h> |
1259 | |
1260 | int compat_import_iovec(int type, const struct compat_iovec __user * uvector, |
1261 | unsigned nr_segs, unsigned fast_segs, |
1262 | struct iovec **iov, struct iov_iter *i) |
1263 | { |
1264 | ssize_t n; |
1265 | struct iovec *p; |
1266 | n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs, |
1267 | *iov, &p); |
1268 | if (n < 0) { |
1269 | if (p != *iov) |
1270 | kfree(p); |
1271 | *iov = NULL; |
1272 | return n; |
1273 | } |
1274 | iov_iter_init(i, type, p, nr_segs, n); |
1275 | *iov = p == *iov ? NULL : p; |
1276 | return 0; |
1277 | } |
1278 | #endif |
1279 | |
1280 | int import_single_range(int rw, void __user *buf, size_t len, |
1281 | struct iovec *iov, struct iov_iter *i) |
1282 | { |
1283 | if (len > MAX_RW_COUNT) |
1284 | len = MAX_RW_COUNT; |
1285 | if (unlikely(!access_ok(!rw, buf, len))) |
1286 | return -EFAULT; |
1287 | |
1288 | iov->iov_base = buf; |
1289 | iov->iov_len = len; |
1290 | iov_iter_init(i, rw, iov, 1, len); |
1291 | return 0; |
1292 | } |
1293 | EXPORT_SYMBOL(import_single_range); |
1294 |