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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 | |
7 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
8 | struct iov_iter *i) |
9 | { |
10 | size_t skip, copy, left, wanted; |
11 | const struct iovec *iov; |
12 | char __user *buf; |
13 | void *kaddr, *from; |
14 | |
15 | if (unlikely(bytes > i->count)) |
16 | bytes = i->count; |
17 | |
18 | if (unlikely(!bytes)) |
19 | return 0; |
20 | |
21 | wanted = bytes; |
22 | iov = i->iov; |
23 | skip = i->iov_offset; |
24 | buf = iov->iov_base + skip; |
25 | copy = min(bytes, iov->iov_len - skip); |
26 | |
27 | if (!fault_in_pages_writeable(buf, copy)) { |
28 | kaddr = kmap_atomic(page); |
29 | from = kaddr + offset; |
30 | |
31 | /* first chunk, usually the only one */ |
32 | left = __copy_to_user_inatomic(buf, from, copy); |
33 | copy -= left; |
34 | skip += copy; |
35 | from += copy; |
36 | bytes -= copy; |
37 | |
38 | while (unlikely(!left && bytes)) { |
39 | iov++; |
40 | buf = iov->iov_base; |
41 | copy = min(bytes, iov->iov_len); |
42 | left = __copy_to_user_inatomic(buf, from, copy); |
43 | copy -= left; |
44 | skip = copy; |
45 | from += copy; |
46 | bytes -= copy; |
47 | } |
48 | if (likely(!bytes)) { |
49 | kunmap_atomic(kaddr); |
50 | goto done; |
51 | } |
52 | offset = from - kaddr; |
53 | buf += copy; |
54 | kunmap_atomic(kaddr); |
55 | copy = min(bytes, iov->iov_len - skip); |
56 | } |
57 | /* Too bad - revert to non-atomic kmap */ |
58 | kaddr = kmap(page); |
59 | from = kaddr + offset; |
60 | left = __copy_to_user(buf, from, copy); |
61 | copy -= left; |
62 | skip += copy; |
63 | from += copy; |
64 | bytes -= copy; |
65 | while (unlikely(!left && bytes)) { |
66 | iov++; |
67 | buf = iov->iov_base; |
68 | copy = min(bytes, iov->iov_len); |
69 | left = __copy_to_user(buf, from, copy); |
70 | copy -= left; |
71 | skip = copy; |
72 | from += copy; |
73 | bytes -= copy; |
74 | } |
75 | kunmap(page); |
76 | done: |
77 | if (skip == iov->iov_len) { |
78 | iov++; |
79 | skip = 0; |
80 | } |
81 | i->count -= wanted - bytes; |
82 | i->nr_segs -= iov - i->iov; |
83 | i->iov = iov; |
84 | i->iov_offset = skip; |
85 | return wanted - bytes; |
86 | } |
87 | |
88 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
89 | struct iov_iter *i) |
90 | { |
91 | size_t skip, copy, left, wanted; |
92 | const struct iovec *iov; |
93 | char __user *buf; |
94 | void *kaddr, *to; |
95 | |
96 | if (unlikely(bytes > i->count)) |
97 | bytes = i->count; |
98 | |
99 | if (unlikely(!bytes)) |
100 | return 0; |
101 | |
102 | wanted = bytes; |
103 | iov = i->iov; |
104 | skip = i->iov_offset; |
105 | buf = iov->iov_base + skip; |
106 | copy = min(bytes, iov->iov_len - skip); |
107 | |
108 | if (!fault_in_pages_readable(buf, copy)) { |
109 | kaddr = kmap_atomic(page); |
110 | to = kaddr + offset; |
111 | |
112 | /* first chunk, usually the only one */ |
113 | left = __copy_from_user_inatomic(to, buf, copy); |
114 | copy -= left; |
115 | skip += copy; |
116 | to += copy; |
117 | bytes -= copy; |
118 | |
119 | while (unlikely(!left && bytes)) { |
120 | iov++; |
121 | buf = iov->iov_base; |
122 | copy = min(bytes, iov->iov_len); |
123 | left = __copy_from_user_inatomic(to, buf, copy); |
124 | copy -= left; |
125 | skip = copy; |
126 | to += copy; |
127 | bytes -= copy; |
128 | } |
129 | if (likely(!bytes)) { |
130 | kunmap_atomic(kaddr); |
131 | goto done; |
132 | } |
133 | offset = to - kaddr; |
134 | buf += copy; |
135 | kunmap_atomic(kaddr); |
136 | copy = min(bytes, iov->iov_len - skip); |
137 | } |
138 | /* Too bad - revert to non-atomic kmap */ |
139 | kaddr = kmap(page); |
140 | to = kaddr + offset; |
141 | left = __copy_from_user(to, buf, copy); |
142 | copy -= left; |
143 | skip += copy; |
144 | to += copy; |
145 | bytes -= copy; |
146 | while (unlikely(!left && bytes)) { |
147 | iov++; |
148 | buf = iov->iov_base; |
149 | copy = min(bytes, iov->iov_len); |
150 | left = __copy_from_user(to, buf, copy); |
151 | copy -= left; |
152 | skip = copy; |
153 | to += copy; |
154 | bytes -= copy; |
155 | } |
156 | kunmap(page); |
157 | done: |
158 | if (skip == iov->iov_len) { |
159 | iov++; |
160 | skip = 0; |
161 | } |
162 | i->count -= wanted - bytes; |
163 | i->nr_segs -= iov - i->iov; |
164 | i->iov = iov; |
165 | i->iov_offset = skip; |
166 | return wanted - bytes; |
167 | } |
168 | |
169 | static size_t __iovec_copy_from_user_inatomic(char *vaddr, |
170 | const struct iovec *iov, size_t base, size_t bytes) |
171 | { |
172 | size_t copied = 0, left = 0; |
173 | |
174 | while (bytes) { |
175 | char __user *buf = iov->iov_base + base; |
176 | int copy = min(bytes, iov->iov_len - base); |
177 | |
178 | base = 0; |
179 | left = __copy_from_user_inatomic(vaddr, buf, copy); |
180 | copied += copy; |
181 | bytes -= copy; |
182 | vaddr += copy; |
183 | iov++; |
184 | |
185 | if (unlikely(left)) |
186 | break; |
187 | } |
188 | return copied - left; |
189 | } |
190 | |
191 | /* |
192 | * Copy as much as we can into the page and return the number of bytes which |
193 | * were successfully copied. If a fault is encountered then return the number of |
194 | * bytes which were copied. |
195 | */ |
196 | static size_t copy_from_user_atomic_iovec(struct page *page, |
197 | struct iov_iter *i, unsigned long offset, size_t bytes) |
198 | { |
199 | char *kaddr; |
200 | size_t copied; |
201 | |
202 | kaddr = kmap_atomic(page); |
203 | if (likely(i->nr_segs == 1)) { |
204 | int left; |
205 | char __user *buf = i->iov->iov_base + i->iov_offset; |
206 | left = __copy_from_user_inatomic(kaddr + offset, buf, bytes); |
207 | copied = bytes - left; |
208 | } else { |
209 | copied = __iovec_copy_from_user_inatomic(kaddr + offset, |
210 | i->iov, i->iov_offset, bytes); |
211 | } |
212 | kunmap_atomic(kaddr); |
213 | |
214 | return copied; |
215 | } |
216 | |
217 | static void advance_iovec(struct iov_iter *i, size_t bytes) |
218 | { |
219 | BUG_ON(i->count < bytes); |
220 | |
221 | if (likely(i->nr_segs == 1)) { |
222 | i->iov_offset += bytes; |
223 | i->count -= bytes; |
224 | } else { |
225 | const struct iovec *iov = i->iov; |
226 | size_t base = i->iov_offset; |
227 | unsigned long nr_segs = i->nr_segs; |
228 | |
229 | /* |
230 | * The !iov->iov_len check ensures we skip over unlikely |
231 | * zero-length segments (without overruning the iovec). |
232 | */ |
233 | while (bytes || unlikely(i->count && !iov->iov_len)) { |
234 | int copy; |
235 | |
236 | copy = min(bytes, iov->iov_len - base); |
237 | BUG_ON(!i->count || i->count < copy); |
238 | i->count -= copy; |
239 | bytes -= copy; |
240 | base += copy; |
241 | if (iov->iov_len == base) { |
242 | iov++; |
243 | nr_segs--; |
244 | base = 0; |
245 | } |
246 | } |
247 | i->iov = iov; |
248 | i->iov_offset = base; |
249 | i->nr_segs = nr_segs; |
250 | } |
251 | } |
252 | |
253 | /* |
254 | * Fault in the first iovec of the given iov_iter, to a maximum length |
255 | * of bytes. Returns 0 on success, or non-zero if the memory could not be |
256 | * accessed (ie. because it is an invalid address). |
257 | * |
258 | * writev-intensive code may want this to prefault several iovecs -- that |
259 | * would be possible (callers must not rely on the fact that _only_ the |
260 | * first iovec will be faulted with the current implementation). |
261 | */ |
262 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) |
263 | { |
264 | if (!(i->type & ITER_BVEC)) { |
265 | char __user *buf = i->iov->iov_base + i->iov_offset; |
266 | bytes = min(bytes, i->iov->iov_len - i->iov_offset); |
267 | return fault_in_pages_readable(buf, bytes); |
268 | } |
269 | return 0; |
270 | } |
271 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
272 | |
273 | static unsigned long alignment_iovec(const struct iov_iter *i) |
274 | { |
275 | const struct iovec *iov = i->iov; |
276 | unsigned long res; |
277 | size_t size = i->count; |
278 | size_t n; |
279 | |
280 | if (!size) |
281 | return 0; |
282 | |
283 | res = (unsigned long)iov->iov_base + i->iov_offset; |
284 | n = iov->iov_len - i->iov_offset; |
285 | if (n >= size) |
286 | return res | size; |
287 | size -= n; |
288 | res |= n; |
289 | while (size > (++iov)->iov_len) { |
290 | res |= (unsigned long)iov->iov_base | iov->iov_len; |
291 | size -= iov->iov_len; |
292 | } |
293 | res |= (unsigned long)iov->iov_base | size; |
294 | return res; |
295 | } |
296 | |
297 | void iov_iter_init(struct iov_iter *i, int direction, |
298 | const struct iovec *iov, unsigned long nr_segs, |
299 | size_t count) |
300 | { |
301 | /* It will get better. Eventually... */ |
302 | if (segment_eq(get_fs(), KERNEL_DS)) |
303 | direction |= ITER_KVEC; |
304 | i->type = direction; |
305 | i->iov = iov; |
306 | i->nr_segs = nr_segs; |
307 | i->iov_offset = 0; |
308 | i->count = count; |
309 | } |
310 | EXPORT_SYMBOL(iov_iter_init); |
311 | |
312 | static ssize_t get_pages_iovec(struct iov_iter *i, |
313 | struct page **pages, size_t maxsize, |
314 | size_t *start) |
315 | { |
316 | size_t offset = i->iov_offset; |
317 | const struct iovec *iov = i->iov; |
318 | size_t len; |
319 | unsigned long addr; |
320 | int n; |
321 | int res; |
322 | |
323 | len = iov->iov_len - offset; |
324 | if (len > i->count) |
325 | len = i->count; |
326 | if (len > maxsize) |
327 | len = maxsize; |
328 | addr = (unsigned long)iov->iov_base + offset; |
329 | len += *start = addr & (PAGE_SIZE - 1); |
330 | addr &= ~(PAGE_SIZE - 1); |
331 | n = (len + PAGE_SIZE - 1) / PAGE_SIZE; |
332 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages); |
333 | if (unlikely(res < 0)) |
334 | return res; |
335 | return (res == n ? len : res * PAGE_SIZE) - *start; |
336 | } |
337 | |
338 | static ssize_t get_pages_alloc_iovec(struct iov_iter *i, |
339 | struct page ***pages, size_t maxsize, |
340 | size_t *start) |
341 | { |
342 | size_t offset = i->iov_offset; |
343 | const struct iovec *iov = i->iov; |
344 | size_t len; |
345 | unsigned long addr; |
346 | void *p; |
347 | int n; |
348 | int res; |
349 | |
350 | len = iov->iov_len - offset; |
351 | if (len > i->count) |
352 | len = i->count; |
353 | if (len > maxsize) |
354 | len = maxsize; |
355 | addr = (unsigned long)iov->iov_base + offset; |
356 | len += *start = addr & (PAGE_SIZE - 1); |
357 | addr &= ~(PAGE_SIZE - 1); |
358 | n = (len + PAGE_SIZE - 1) / PAGE_SIZE; |
359 | |
360 | p = kmalloc(n * sizeof(struct page *), GFP_KERNEL); |
361 | if (!p) |
362 | p = vmalloc(n * sizeof(struct page *)); |
363 | if (!p) |
364 | return -ENOMEM; |
365 | |
366 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p); |
367 | if (unlikely(res < 0)) { |
368 | kvfree(p); |
369 | return res; |
370 | } |
371 | *pages = p; |
372 | return (res == n ? len : res * PAGE_SIZE) - *start; |
373 | } |
374 | |
375 | static int iov_iter_npages_iovec(const struct iov_iter *i, int maxpages) |
376 | { |
377 | size_t offset = i->iov_offset; |
378 | size_t size = i->count; |
379 | const struct iovec *iov = i->iov; |
380 | int npages = 0; |
381 | int n; |
382 | |
383 | for (n = 0; size && n < i->nr_segs; n++, iov++) { |
384 | unsigned long addr = (unsigned long)iov->iov_base + offset; |
385 | size_t len = iov->iov_len - offset; |
386 | offset = 0; |
387 | if (unlikely(!len)) /* empty segment */ |
388 | continue; |
389 | if (len > size) |
390 | len = size; |
391 | npages += (addr + len + PAGE_SIZE - 1) / PAGE_SIZE |
392 | - addr / PAGE_SIZE; |
393 | if (npages >= maxpages) /* don't bother going further */ |
394 | return maxpages; |
395 | size -= len; |
396 | offset = 0; |
397 | } |
398 | return min(npages, maxpages); |
399 | } |
400 | |
401 | static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len) |
402 | { |
403 | char *from = kmap_atomic(page); |
404 | memcpy(to, from + offset, len); |
405 | kunmap_atomic(from); |
406 | } |
407 | |
408 | static void memcpy_to_page(struct page *page, size_t offset, char *from, size_t len) |
409 | { |
410 | char *to = kmap_atomic(page); |
411 | memcpy(to + offset, from, len); |
412 | kunmap_atomic(to); |
413 | } |
414 | |
415 | static size_t copy_page_to_iter_bvec(struct page *page, size_t offset, size_t bytes, |
416 | struct iov_iter *i) |
417 | { |
418 | size_t skip, copy, wanted; |
419 | const struct bio_vec *bvec; |
420 | void *kaddr, *from; |
421 | |
422 | if (unlikely(bytes > i->count)) |
423 | bytes = i->count; |
424 | |
425 | if (unlikely(!bytes)) |
426 | return 0; |
427 | |
428 | wanted = bytes; |
429 | bvec = i->bvec; |
430 | skip = i->iov_offset; |
431 | copy = min_t(size_t, bytes, bvec->bv_len - skip); |
432 | |
433 | kaddr = kmap_atomic(page); |
434 | from = kaddr + offset; |
435 | memcpy_to_page(bvec->bv_page, skip + bvec->bv_offset, from, copy); |
436 | skip += copy; |
437 | from += copy; |
438 | bytes -= copy; |
439 | while (bytes) { |
440 | bvec++; |
441 | copy = min(bytes, (size_t)bvec->bv_len); |
442 | memcpy_to_page(bvec->bv_page, bvec->bv_offset, from, copy); |
443 | skip = copy; |
444 | from += copy; |
445 | bytes -= copy; |
446 | } |
447 | kunmap_atomic(kaddr); |
448 | if (skip == bvec->bv_len) { |
449 | bvec++; |
450 | skip = 0; |
451 | } |
452 | i->count -= wanted - bytes; |
453 | i->nr_segs -= bvec - i->bvec; |
454 | i->bvec = bvec; |
455 | i->iov_offset = skip; |
456 | return wanted - bytes; |
457 | } |
458 | |
459 | static size_t copy_page_from_iter_bvec(struct page *page, size_t offset, size_t bytes, |
460 | struct iov_iter *i) |
461 | { |
462 | size_t skip, copy, wanted; |
463 | const struct bio_vec *bvec; |
464 | void *kaddr, *to; |
465 | |
466 | if (unlikely(bytes > i->count)) |
467 | bytes = i->count; |
468 | |
469 | if (unlikely(!bytes)) |
470 | return 0; |
471 | |
472 | wanted = bytes; |
473 | bvec = i->bvec; |
474 | skip = i->iov_offset; |
475 | |
476 | kaddr = kmap_atomic(page); |
477 | |
478 | to = kaddr + offset; |
479 | |
480 | copy = min(bytes, bvec->bv_len - skip); |
481 | |
482 | memcpy_from_page(to, bvec->bv_page, bvec->bv_offset + skip, copy); |
483 | |
484 | to += copy; |
485 | skip += copy; |
486 | bytes -= copy; |
487 | |
488 | while (bytes) { |
489 | bvec++; |
490 | copy = min(bytes, (size_t)bvec->bv_len); |
491 | memcpy_from_page(to, bvec->bv_page, bvec->bv_offset, copy); |
492 | skip = copy; |
493 | to += copy; |
494 | bytes -= copy; |
495 | } |
496 | kunmap_atomic(kaddr); |
497 | if (skip == bvec->bv_len) { |
498 | bvec++; |
499 | skip = 0; |
500 | } |
501 | i->count -= wanted; |
502 | i->nr_segs -= bvec - i->bvec; |
503 | i->bvec = bvec; |
504 | i->iov_offset = skip; |
505 | return wanted; |
506 | } |
507 | |
508 | static size_t copy_from_user_bvec(struct page *page, |
509 | struct iov_iter *i, unsigned long offset, size_t bytes) |
510 | { |
511 | char *kaddr; |
512 | size_t left; |
513 | const struct bio_vec *bvec; |
514 | size_t base = i->iov_offset; |
515 | |
516 | kaddr = kmap_atomic(page); |
517 | for (left = bytes, bvec = i->bvec; left; bvec++, base = 0) { |
518 | size_t copy = min(left, bvec->bv_len - base); |
519 | if (!bvec->bv_len) |
520 | continue; |
521 | memcpy_from_page(kaddr + offset, bvec->bv_page, |
522 | bvec->bv_offset + base, copy); |
523 | offset += copy; |
524 | left -= copy; |
525 | } |
526 | kunmap_atomic(kaddr); |
527 | return bytes; |
528 | } |
529 | |
530 | static void advance_bvec(struct iov_iter *i, size_t bytes) |
531 | { |
532 | BUG_ON(i->count < bytes); |
533 | |
534 | if (likely(i->nr_segs == 1)) { |
535 | i->iov_offset += bytes; |
536 | i->count -= bytes; |
537 | } else { |
538 | const struct bio_vec *bvec = i->bvec; |
539 | size_t base = i->iov_offset; |
540 | unsigned long nr_segs = i->nr_segs; |
541 | |
542 | /* |
543 | * The !iov->iov_len check ensures we skip over unlikely |
544 | * zero-length segments (without overruning the iovec). |
545 | */ |
546 | while (bytes || unlikely(i->count && !bvec->bv_len)) { |
547 | int copy; |
548 | |
549 | copy = min(bytes, bvec->bv_len - base); |
550 | BUG_ON(!i->count || i->count < copy); |
551 | i->count -= copy; |
552 | bytes -= copy; |
553 | base += copy; |
554 | if (bvec->bv_len == base) { |
555 | bvec++; |
556 | nr_segs--; |
557 | base = 0; |
558 | } |
559 | } |
560 | i->bvec = bvec; |
561 | i->iov_offset = base; |
562 | i->nr_segs = nr_segs; |
563 | } |
564 | } |
565 | |
566 | static unsigned long alignment_bvec(const struct iov_iter *i) |
567 | { |
568 | const struct bio_vec *bvec = i->bvec; |
569 | unsigned long res; |
570 | size_t size = i->count; |
571 | size_t n; |
572 | |
573 | if (!size) |
574 | return 0; |
575 | |
576 | res = bvec->bv_offset + i->iov_offset; |
577 | n = bvec->bv_len - i->iov_offset; |
578 | if (n >= size) |
579 | return res | size; |
580 | size -= n; |
581 | res |= n; |
582 | while (size > (++bvec)->bv_len) { |
583 | res |= bvec->bv_offset | bvec->bv_len; |
584 | size -= bvec->bv_len; |
585 | } |
586 | res |= bvec->bv_offset | size; |
587 | return res; |
588 | } |
589 | |
590 | static ssize_t get_pages_bvec(struct iov_iter *i, |
591 | struct page **pages, size_t maxsize, |
592 | size_t *start) |
593 | { |
594 | const struct bio_vec *bvec = i->bvec; |
595 | size_t len = bvec->bv_len - i->iov_offset; |
596 | if (len > i->count) |
597 | len = i->count; |
598 | if (len > maxsize) |
599 | len = maxsize; |
600 | *start = bvec->bv_offset + i->iov_offset; |
601 | |
602 | get_page(*pages = bvec->bv_page); |
603 | |
604 | return len; |
605 | } |
606 | |
607 | static ssize_t get_pages_alloc_bvec(struct iov_iter *i, |
608 | struct page ***pages, size_t maxsize, |
609 | size_t *start) |
610 | { |
611 | const struct bio_vec *bvec = i->bvec; |
612 | size_t len = bvec->bv_len - i->iov_offset; |
613 | if (len > i->count) |
614 | len = i->count; |
615 | if (len > maxsize) |
616 | len = maxsize; |
617 | *start = bvec->bv_offset + i->iov_offset; |
618 | |
619 | *pages = kmalloc(sizeof(struct page *), GFP_KERNEL); |
620 | if (!*pages) |
621 | return -ENOMEM; |
622 | |
623 | get_page(**pages = bvec->bv_page); |
624 | |
625 | return len; |
626 | } |
627 | |
628 | static int iov_iter_npages_bvec(const struct iov_iter *i, int maxpages) |
629 | { |
630 | size_t offset = i->iov_offset; |
631 | size_t size = i->count; |
632 | const struct bio_vec *bvec = i->bvec; |
633 | int npages = 0; |
634 | int n; |
635 | |
636 | for (n = 0; size && n < i->nr_segs; n++, bvec++) { |
637 | size_t len = bvec->bv_len - offset; |
638 | offset = 0; |
639 | if (unlikely(!len)) /* empty segment */ |
640 | continue; |
641 | if (len > size) |
642 | len = size; |
643 | npages++; |
644 | if (npages >= maxpages) /* don't bother going further */ |
645 | return maxpages; |
646 | size -= len; |
647 | offset = 0; |
648 | } |
649 | return min(npages, maxpages); |
650 | } |
651 | |
652 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
653 | struct iov_iter *i) |
654 | { |
655 | if (i->type & ITER_BVEC) |
656 | return copy_page_to_iter_bvec(page, offset, bytes, i); |
657 | else |
658 | return copy_page_to_iter_iovec(page, offset, bytes, i); |
659 | } |
660 | EXPORT_SYMBOL(copy_page_to_iter); |
661 | |
662 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
663 | struct iov_iter *i) |
664 | { |
665 | if (i->type & ITER_BVEC) |
666 | return copy_page_from_iter_bvec(page, offset, bytes, i); |
667 | else |
668 | return copy_page_from_iter_iovec(page, offset, bytes, i); |
669 | } |
670 | EXPORT_SYMBOL(copy_page_from_iter); |
671 | |
672 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
673 | struct iov_iter *i, unsigned long offset, size_t bytes) |
674 | { |
675 | if (i->type & ITER_BVEC) |
676 | return copy_from_user_bvec(page, i, offset, bytes); |
677 | else |
678 | return copy_from_user_atomic_iovec(page, i, offset, bytes); |
679 | } |
680 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); |
681 | |
682 | void iov_iter_advance(struct iov_iter *i, size_t size) |
683 | { |
684 | if (i->type & ITER_BVEC) |
685 | advance_bvec(i, size); |
686 | else |
687 | advance_iovec(i, size); |
688 | } |
689 | EXPORT_SYMBOL(iov_iter_advance); |
690 | |
691 | /* |
692 | * Return the count of just the current iov_iter segment. |
693 | */ |
694 | size_t iov_iter_single_seg_count(const struct iov_iter *i) |
695 | { |
696 | if (i->nr_segs == 1) |
697 | return i->count; |
698 | else if (i->type & ITER_BVEC) |
699 | return min(i->count, i->iov->iov_len - i->iov_offset); |
700 | else |
701 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
702 | } |
703 | EXPORT_SYMBOL(iov_iter_single_seg_count); |
704 | |
705 | unsigned long iov_iter_alignment(const struct iov_iter *i) |
706 | { |
707 | if (i->type & ITER_BVEC) |
708 | return alignment_bvec(i); |
709 | else |
710 | return alignment_iovec(i); |
711 | } |
712 | EXPORT_SYMBOL(iov_iter_alignment); |
713 | |
714 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
715 | struct page **pages, size_t maxsize, |
716 | size_t *start) |
717 | { |
718 | if (i->type & ITER_BVEC) |
719 | return get_pages_bvec(i, pages, maxsize, start); |
720 | else |
721 | return get_pages_iovec(i, pages, maxsize, start); |
722 | } |
723 | EXPORT_SYMBOL(iov_iter_get_pages); |
724 | |
725 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
726 | struct page ***pages, size_t maxsize, |
727 | size_t *start) |
728 | { |
729 | if (i->type & ITER_BVEC) |
730 | return get_pages_alloc_bvec(i, pages, maxsize, start); |
731 | else |
732 | return get_pages_alloc_iovec(i, pages, maxsize, start); |
733 | } |
734 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); |
735 | |
736 | int iov_iter_npages(const struct iov_iter *i, int maxpages) |
737 | { |
738 | if (i->type & ITER_BVEC) |
739 | return iov_iter_npages_bvec(i, maxpages); |
740 | else |
741 | return iov_iter_npages_iovec(i, maxpages); |
742 | } |
743 | EXPORT_SYMBOL(iov_iter_npages); |
744 |
Branches:
ben-wpan
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javiroman/ks7010
jz-2.6.34
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9