Commit | Line | Data |
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4f18cd31 AV |
1 | #include <linux/export.h> |
2 | #include <linux/uio.h> | |
3 | #include <linux/pagemap.h> | |
91f79c43 AV |
4 | #include <linux/slab.h> |
5 | #include <linux/vmalloc.h> | |
4f18cd31 | 6 | |
04a31165 AV |
7 | #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ |
8 | size_t left; \ | |
9 | size_t wanted = n; \ | |
10 | __p = i->iov; \ | |
11 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
12 | if (likely(__v.iov_len)) { \ | |
13 | __v.iov_base = __p->iov_base + skip; \ | |
14 | left = (STEP); \ | |
15 | __v.iov_len -= left; \ | |
16 | skip += __v.iov_len; \ | |
17 | n -= __v.iov_len; \ | |
18 | } else { \ | |
19 | left = 0; \ | |
20 | } \ | |
21 | while (unlikely(!left && n)) { \ | |
22 | __p++; \ | |
23 | __v.iov_len = min(n, __p->iov_len); \ | |
24 | if (unlikely(!__v.iov_len)) \ | |
25 | continue; \ | |
26 | __v.iov_base = __p->iov_base; \ | |
27 | left = (STEP); \ | |
28 | __v.iov_len -= left; \ | |
29 | skip = __v.iov_len; \ | |
30 | n -= __v.iov_len; \ | |
31 | } \ | |
32 | n = wanted - n; \ | |
33 | } | |
34 | ||
35 | #define iterate_bvec(i, n, __v, __p, skip, STEP) { \ | |
36 | size_t wanted = n; \ | |
37 | __p = i->bvec; \ | |
38 | __v.bv_len = min_t(size_t, n, __p->bv_len - skip); \ | |
39 | if (likely(__v.bv_len)) { \ | |
40 | __v.bv_page = __p->bv_page; \ | |
41 | __v.bv_offset = __p->bv_offset + skip; \ | |
42 | (void)(STEP); \ | |
43 | skip += __v.bv_len; \ | |
44 | n -= __v.bv_len; \ | |
45 | } \ | |
46 | while (unlikely(n)) { \ | |
47 | __p++; \ | |
48 | __v.bv_len = min_t(size_t, n, __p->bv_len); \ | |
49 | if (unlikely(!__v.bv_len)) \ | |
50 | continue; \ | |
51 | __v.bv_page = __p->bv_page; \ | |
52 | __v.bv_offset = __p->bv_offset; \ | |
53 | (void)(STEP); \ | |
54 | skip = __v.bv_len; \ | |
55 | n -= __v.bv_len; \ | |
56 | } \ | |
57 | n = wanted; \ | |
58 | } | |
59 | ||
60 | #define iterate_all_kinds(i, n, v, I, B) { \ | |
61 | size_t skip = i->iov_offset; \ | |
62 | if (unlikely(i->type & ITER_BVEC)) { \ | |
63 | const struct bio_vec *bvec; \ | |
64 | struct bio_vec v; \ | |
65 | iterate_bvec(i, n, v, bvec, skip, (B)) \ | |
66 | } else { \ | |
67 | const struct iovec *iov; \ | |
68 | struct iovec v; \ | |
69 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
70 | } \ | |
71 | } | |
72 | ||
7ce2a91e AV |
73 | #define iterate_and_advance(i, n, v, I, B) { \ |
74 | size_t skip = i->iov_offset; \ | |
75 | if (unlikely(i->type & ITER_BVEC)) { \ | |
76 | const struct bio_vec *bvec; \ | |
77 | struct bio_vec v; \ | |
78 | iterate_bvec(i, n, v, bvec, skip, (B)) \ | |
79 | if (skip == bvec->bv_len) { \ | |
80 | bvec++; \ | |
81 | skip = 0; \ | |
82 | } \ | |
83 | i->nr_segs -= bvec - i->bvec; \ | |
84 | i->bvec = bvec; \ | |
85 | } else { \ | |
86 | const struct iovec *iov; \ | |
87 | struct iovec v; \ | |
88 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
89 | if (skip == iov->iov_len) { \ | |
90 | iov++; \ | |
91 | skip = 0; \ | |
92 | } \ | |
93 | i->nr_segs -= iov - i->iov; \ | |
94 | i->iov = iov; \ | |
95 | } \ | |
96 | i->count -= n; \ | |
97 | i->iov_offset = skip; \ | |
98 | } | |
99 | ||
c35e0248 MW |
100 | static size_t copy_to_iter_iovec(void *from, size_t bytes, struct iov_iter *i) |
101 | { | |
102 | size_t skip, copy, left, wanted; | |
103 | const struct iovec *iov; | |
104 | char __user *buf; | |
105 | ||
106 | if (unlikely(bytes > i->count)) | |
107 | bytes = i->count; | |
108 | ||
109 | if (unlikely(!bytes)) | |
110 | return 0; | |
111 | ||
112 | wanted = bytes; | |
113 | iov = i->iov; | |
114 | skip = i->iov_offset; | |
115 | buf = iov->iov_base + skip; | |
116 | copy = min(bytes, iov->iov_len - skip); | |
117 | ||
118 | left = __copy_to_user(buf, from, copy); | |
119 | copy -= left; | |
120 | skip += copy; | |
121 | from += copy; | |
122 | bytes -= copy; | |
123 | while (unlikely(!left && bytes)) { | |
124 | iov++; | |
125 | buf = iov->iov_base; | |
126 | copy = min(bytes, iov->iov_len); | |
127 | left = __copy_to_user(buf, from, copy); | |
128 | copy -= left; | |
129 | skip = copy; | |
130 | from += copy; | |
131 | bytes -= copy; | |
132 | } | |
133 | ||
134 | if (skip == iov->iov_len) { | |
135 | iov++; | |
136 | skip = 0; | |
137 | } | |
138 | i->count -= wanted - bytes; | |
139 | i->nr_segs -= iov - i->iov; | |
140 | i->iov = iov; | |
141 | i->iov_offset = skip; | |
142 | return wanted - bytes; | |
143 | } | |
144 | ||
145 | static size_t copy_from_iter_iovec(void *to, size_t bytes, struct iov_iter *i) | |
146 | { | |
147 | size_t skip, copy, left, wanted; | |
148 | const struct iovec *iov; | |
149 | char __user *buf; | |
150 | ||
151 | if (unlikely(bytes > i->count)) | |
152 | bytes = i->count; | |
153 | ||
154 | if (unlikely(!bytes)) | |
155 | return 0; | |
156 | ||
157 | wanted = bytes; | |
158 | iov = i->iov; | |
159 | skip = i->iov_offset; | |
160 | buf = iov->iov_base + skip; | |
161 | copy = min(bytes, iov->iov_len - skip); | |
162 | ||
163 | left = __copy_from_user(to, buf, copy); | |
164 | copy -= left; | |
165 | skip += copy; | |
166 | to += copy; | |
167 | bytes -= copy; | |
168 | while (unlikely(!left && bytes)) { | |
169 | iov++; | |
170 | buf = iov->iov_base; | |
171 | copy = min(bytes, iov->iov_len); | |
172 | left = __copy_from_user(to, buf, copy); | |
173 | copy -= left; | |
174 | skip = copy; | |
175 | to += copy; | |
176 | bytes -= copy; | |
177 | } | |
178 | ||
179 | if (skip == iov->iov_len) { | |
180 | iov++; | |
181 | skip = 0; | |
182 | } | |
183 | i->count -= wanted - bytes; | |
184 | i->nr_segs -= iov - i->iov; | |
185 | i->iov = iov; | |
186 | i->iov_offset = skip; | |
187 | return wanted - bytes; | |
188 | } | |
189 | ||
62a8067a | 190 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
191 | struct iov_iter *i) |
192 | { | |
193 | size_t skip, copy, left, wanted; | |
194 | const struct iovec *iov; | |
195 | char __user *buf; | |
196 | void *kaddr, *from; | |
197 | ||
198 | if (unlikely(bytes > i->count)) | |
199 | bytes = i->count; | |
200 | ||
201 | if (unlikely(!bytes)) | |
202 | return 0; | |
203 | ||
204 | wanted = bytes; | |
205 | iov = i->iov; | |
206 | skip = i->iov_offset; | |
207 | buf = iov->iov_base + skip; | |
208 | copy = min(bytes, iov->iov_len - skip); | |
209 | ||
210 | if (!fault_in_pages_writeable(buf, copy)) { | |
211 | kaddr = kmap_atomic(page); | |
212 | from = kaddr + offset; | |
213 | ||
214 | /* first chunk, usually the only one */ | |
215 | left = __copy_to_user_inatomic(buf, from, copy); | |
216 | copy -= left; | |
217 | skip += copy; | |
218 | from += copy; | |
219 | bytes -= copy; | |
220 | ||
221 | while (unlikely(!left && bytes)) { | |
222 | iov++; | |
223 | buf = iov->iov_base; | |
224 | copy = min(bytes, iov->iov_len); | |
225 | left = __copy_to_user_inatomic(buf, from, copy); | |
226 | copy -= left; | |
227 | skip = copy; | |
228 | from += copy; | |
229 | bytes -= copy; | |
230 | } | |
231 | if (likely(!bytes)) { | |
232 | kunmap_atomic(kaddr); | |
233 | goto done; | |
234 | } | |
235 | offset = from - kaddr; | |
236 | buf += copy; | |
237 | kunmap_atomic(kaddr); | |
238 | copy = min(bytes, iov->iov_len - skip); | |
239 | } | |
240 | /* Too bad - revert to non-atomic kmap */ | |
241 | kaddr = kmap(page); | |
242 | from = kaddr + offset; | |
243 | left = __copy_to_user(buf, from, copy); | |
244 | copy -= left; | |
245 | skip += copy; | |
246 | from += copy; | |
247 | bytes -= copy; | |
248 | while (unlikely(!left && bytes)) { | |
249 | iov++; | |
250 | buf = iov->iov_base; | |
251 | copy = min(bytes, iov->iov_len); | |
252 | left = __copy_to_user(buf, from, copy); | |
253 | copy -= left; | |
254 | skip = copy; | |
255 | from += copy; | |
256 | bytes -= copy; | |
257 | } | |
258 | kunmap(page); | |
259 | done: | |
81055e58 AV |
260 | if (skip == iov->iov_len) { |
261 | iov++; | |
262 | skip = 0; | |
263 | } | |
4f18cd31 AV |
264 | i->count -= wanted - bytes; |
265 | i->nr_segs -= iov - i->iov; | |
266 | i->iov = iov; | |
267 | i->iov_offset = skip; | |
268 | return wanted - bytes; | |
269 | } | |
4f18cd31 | 270 | |
62a8067a | 271 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
272 | struct iov_iter *i) |
273 | { | |
274 | size_t skip, copy, left, wanted; | |
275 | const struct iovec *iov; | |
276 | char __user *buf; | |
277 | void *kaddr, *to; | |
278 | ||
279 | if (unlikely(bytes > i->count)) | |
280 | bytes = i->count; | |
281 | ||
282 | if (unlikely(!bytes)) | |
283 | return 0; | |
284 | ||
285 | wanted = bytes; | |
286 | iov = i->iov; | |
287 | skip = i->iov_offset; | |
288 | buf = iov->iov_base + skip; | |
289 | copy = min(bytes, iov->iov_len - skip); | |
290 | ||
291 | if (!fault_in_pages_readable(buf, copy)) { | |
292 | kaddr = kmap_atomic(page); | |
293 | to = kaddr + offset; | |
294 | ||
295 | /* first chunk, usually the only one */ | |
296 | left = __copy_from_user_inatomic(to, buf, copy); | |
297 | copy -= left; | |
298 | skip += copy; | |
299 | to += copy; | |
300 | bytes -= copy; | |
301 | ||
302 | while (unlikely(!left && bytes)) { | |
303 | iov++; | |
304 | buf = iov->iov_base; | |
305 | copy = min(bytes, iov->iov_len); | |
306 | left = __copy_from_user_inatomic(to, buf, copy); | |
307 | copy -= left; | |
308 | skip = copy; | |
309 | to += copy; | |
310 | bytes -= copy; | |
311 | } | |
312 | if (likely(!bytes)) { | |
313 | kunmap_atomic(kaddr); | |
314 | goto done; | |
315 | } | |
316 | offset = to - kaddr; | |
317 | buf += copy; | |
318 | kunmap_atomic(kaddr); | |
319 | copy = min(bytes, iov->iov_len - skip); | |
320 | } | |
321 | /* Too bad - revert to non-atomic kmap */ | |
322 | kaddr = kmap(page); | |
323 | to = kaddr + offset; | |
324 | left = __copy_from_user(to, buf, copy); | |
325 | copy -= left; | |
326 | skip += copy; | |
327 | to += copy; | |
328 | bytes -= copy; | |
329 | while (unlikely(!left && bytes)) { | |
330 | iov++; | |
331 | buf = iov->iov_base; | |
332 | copy = min(bytes, iov->iov_len); | |
333 | left = __copy_from_user(to, buf, copy); | |
334 | copy -= left; | |
335 | skip = copy; | |
336 | to += copy; | |
337 | bytes -= copy; | |
338 | } | |
339 | kunmap(page); | |
340 | done: | |
81055e58 AV |
341 | if (skip == iov->iov_len) { |
342 | iov++; | |
343 | skip = 0; | |
344 | } | |
f0d1bec9 AV |
345 | i->count -= wanted - bytes; |
346 | i->nr_segs -= iov - i->iov; | |
347 | i->iov = iov; | |
348 | i->iov_offset = skip; | |
349 | return wanted - bytes; | |
350 | } | |
f0d1bec9 | 351 | |
c35e0248 MW |
352 | static size_t zero_iovec(size_t bytes, struct iov_iter *i) |
353 | { | |
354 | size_t skip, copy, left, wanted; | |
355 | const struct iovec *iov; | |
356 | char __user *buf; | |
357 | ||
358 | if (unlikely(bytes > i->count)) | |
359 | bytes = i->count; | |
360 | ||
361 | if (unlikely(!bytes)) | |
362 | return 0; | |
363 | ||
364 | wanted = bytes; | |
365 | iov = i->iov; | |
366 | skip = i->iov_offset; | |
367 | buf = iov->iov_base + skip; | |
368 | copy = min(bytes, iov->iov_len - skip); | |
369 | ||
370 | left = __clear_user(buf, copy); | |
371 | copy -= left; | |
372 | skip += copy; | |
373 | bytes -= copy; | |
374 | ||
375 | while (unlikely(!left && bytes)) { | |
376 | iov++; | |
377 | buf = iov->iov_base; | |
378 | copy = min(bytes, iov->iov_len); | |
379 | left = __clear_user(buf, copy); | |
380 | copy -= left; | |
381 | skip = copy; | |
382 | bytes -= copy; | |
383 | } | |
384 | ||
385 | if (skip == iov->iov_len) { | |
386 | iov++; | |
387 | skip = 0; | |
388 | } | |
389 | i->count -= wanted - bytes; | |
390 | i->nr_segs -= iov - i->iov; | |
391 | i->iov = iov; | |
392 | i->iov_offset = skip; | |
393 | return wanted - bytes; | |
394 | } | |
395 | ||
4f18cd31 AV |
396 | /* |
397 | * Fault in the first iovec of the given iov_iter, to a maximum length | |
398 | * of bytes. Returns 0 on success, or non-zero if the memory could not be | |
399 | * accessed (ie. because it is an invalid address). | |
400 | * | |
401 | * writev-intensive code may want this to prefault several iovecs -- that | |
402 | * would be possible (callers must not rely on the fact that _only_ the | |
403 | * first iovec will be faulted with the current implementation). | |
404 | */ | |
405 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) | |
406 | { | |
62a8067a AV |
407 | if (!(i->type & ITER_BVEC)) { |
408 | char __user *buf = i->iov->iov_base + i->iov_offset; | |
409 | bytes = min(bytes, i->iov->iov_len - i->iov_offset); | |
410 | return fault_in_pages_readable(buf, bytes); | |
411 | } | |
412 | return 0; | |
4f18cd31 AV |
413 | } |
414 | EXPORT_SYMBOL(iov_iter_fault_in_readable); | |
415 | ||
71d8e532 AV |
416 | void iov_iter_init(struct iov_iter *i, int direction, |
417 | const struct iovec *iov, unsigned long nr_segs, | |
418 | size_t count) | |
419 | { | |
420 | /* It will get better. Eventually... */ | |
421 | if (segment_eq(get_fs(), KERNEL_DS)) | |
62a8067a | 422 | direction |= ITER_KVEC; |
71d8e532 AV |
423 | i->type = direction; |
424 | i->iov = iov; | |
425 | i->nr_segs = nr_segs; | |
426 | i->iov_offset = 0; | |
427 | i->count = count; | |
428 | } | |
429 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 430 | |
62a8067a | 431 | static ssize_t get_pages_iovec(struct iov_iter *i, |
2c80929c | 432 | struct page **pages, size_t maxsize, unsigned maxpages, |
7b2c99d1 AV |
433 | size_t *start) |
434 | { | |
435 | size_t offset = i->iov_offset; | |
436 | const struct iovec *iov = i->iov; | |
437 | size_t len; | |
438 | unsigned long addr; | |
439 | int n; | |
440 | int res; | |
441 | ||
442 | len = iov->iov_len - offset; | |
443 | if (len > i->count) | |
444 | len = i->count; | |
2c80929c MS |
445 | if (len > maxsize) |
446 | len = maxsize; | |
7b2c99d1 AV |
447 | addr = (unsigned long)iov->iov_base + offset; |
448 | len += *start = addr & (PAGE_SIZE - 1); | |
c7f3888a AV |
449 | if (len > maxpages * PAGE_SIZE) |
450 | len = maxpages * PAGE_SIZE; | |
7b2c99d1 AV |
451 | addr &= ~(PAGE_SIZE - 1); |
452 | n = (len + PAGE_SIZE - 1) / PAGE_SIZE; | |
453 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages); | |
454 | if (unlikely(res < 0)) | |
455 | return res; | |
456 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
457 | } | |
f67da30c | 458 | |
62a8067a | 459 | static ssize_t get_pages_alloc_iovec(struct iov_iter *i, |
91f79c43 AV |
460 | struct page ***pages, size_t maxsize, |
461 | size_t *start) | |
462 | { | |
463 | size_t offset = i->iov_offset; | |
464 | const struct iovec *iov = i->iov; | |
465 | size_t len; | |
466 | unsigned long addr; | |
467 | void *p; | |
468 | int n; | |
469 | int res; | |
470 | ||
471 | len = iov->iov_len - offset; | |
472 | if (len > i->count) | |
473 | len = i->count; | |
474 | if (len > maxsize) | |
475 | len = maxsize; | |
476 | addr = (unsigned long)iov->iov_base + offset; | |
477 | len += *start = addr & (PAGE_SIZE - 1); | |
478 | addr &= ~(PAGE_SIZE - 1); | |
479 | n = (len + PAGE_SIZE - 1) / PAGE_SIZE; | |
480 | ||
481 | p = kmalloc(n * sizeof(struct page *), GFP_KERNEL); | |
482 | if (!p) | |
483 | p = vmalloc(n * sizeof(struct page *)); | |
484 | if (!p) | |
485 | return -ENOMEM; | |
486 | ||
487 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p); | |
488 | if (unlikely(res < 0)) { | |
489 | kvfree(p); | |
490 | return res; | |
491 | } | |
492 | *pages = p; | |
493 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
494 | } | |
91f79c43 | 495 | |
62a8067a | 496 | static int iov_iter_npages_iovec(const struct iov_iter *i, int maxpages) |
f67da30c AV |
497 | { |
498 | size_t offset = i->iov_offset; | |
499 | size_t size = i->count; | |
500 | const struct iovec *iov = i->iov; | |
501 | int npages = 0; | |
502 | int n; | |
503 | ||
504 | for (n = 0; size && n < i->nr_segs; n++, iov++) { | |
505 | unsigned long addr = (unsigned long)iov->iov_base + offset; | |
506 | size_t len = iov->iov_len - offset; | |
507 | offset = 0; | |
508 | if (unlikely(!len)) /* empty segment */ | |
509 | continue; | |
510 | if (len > size) | |
511 | len = size; | |
512 | npages += (addr + len + PAGE_SIZE - 1) / PAGE_SIZE | |
513 | - addr / PAGE_SIZE; | |
514 | if (npages >= maxpages) /* don't bother going further */ | |
515 | return maxpages; | |
516 | size -= len; | |
517 | offset = 0; | |
518 | } | |
519 | return min(npages, maxpages); | |
520 | } | |
62a8067a AV |
521 | |
522 | static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len) | |
523 | { | |
524 | char *from = kmap_atomic(page); | |
525 | memcpy(to, from + offset, len); | |
526 | kunmap_atomic(from); | |
527 | } | |
528 | ||
529 | static void memcpy_to_page(struct page *page, size_t offset, char *from, size_t len) | |
530 | { | |
531 | char *to = kmap_atomic(page); | |
532 | memcpy(to + offset, from, len); | |
533 | kunmap_atomic(to); | |
534 | } | |
535 | ||
c35e0248 MW |
536 | static void memzero_page(struct page *page, size_t offset, size_t len) |
537 | { | |
538 | char *addr = kmap_atomic(page); | |
539 | memset(addr + offset, 0, len); | |
540 | kunmap_atomic(addr); | |
541 | } | |
542 | ||
543 | static size_t copy_to_iter_bvec(void *from, size_t bytes, struct iov_iter *i) | |
62a8067a AV |
544 | { |
545 | size_t skip, copy, wanted; | |
546 | const struct bio_vec *bvec; | |
62a8067a AV |
547 | |
548 | if (unlikely(bytes > i->count)) | |
549 | bytes = i->count; | |
550 | ||
551 | if (unlikely(!bytes)) | |
552 | return 0; | |
553 | ||
554 | wanted = bytes; | |
555 | bvec = i->bvec; | |
556 | skip = i->iov_offset; | |
557 | copy = min_t(size_t, bytes, bvec->bv_len - skip); | |
558 | ||
62a8067a AV |
559 | memcpy_to_page(bvec->bv_page, skip + bvec->bv_offset, from, copy); |
560 | skip += copy; | |
561 | from += copy; | |
562 | bytes -= copy; | |
563 | while (bytes) { | |
564 | bvec++; | |
565 | copy = min(bytes, (size_t)bvec->bv_len); | |
566 | memcpy_to_page(bvec->bv_page, bvec->bv_offset, from, copy); | |
567 | skip = copy; | |
568 | from += copy; | |
569 | bytes -= copy; | |
570 | } | |
62a8067a AV |
571 | if (skip == bvec->bv_len) { |
572 | bvec++; | |
573 | skip = 0; | |
574 | } | |
575 | i->count -= wanted - bytes; | |
576 | i->nr_segs -= bvec - i->bvec; | |
577 | i->bvec = bvec; | |
578 | i->iov_offset = skip; | |
579 | return wanted - bytes; | |
580 | } | |
581 | ||
c35e0248 | 582 | static size_t copy_from_iter_bvec(void *to, size_t bytes, struct iov_iter *i) |
62a8067a AV |
583 | { |
584 | size_t skip, copy, wanted; | |
585 | const struct bio_vec *bvec; | |
62a8067a AV |
586 | |
587 | if (unlikely(bytes > i->count)) | |
588 | bytes = i->count; | |
589 | ||
590 | if (unlikely(!bytes)) | |
591 | return 0; | |
592 | ||
593 | wanted = bytes; | |
594 | bvec = i->bvec; | |
595 | skip = i->iov_offset; | |
596 | ||
62a8067a AV |
597 | copy = min(bytes, bvec->bv_len - skip); |
598 | ||
599 | memcpy_from_page(to, bvec->bv_page, bvec->bv_offset + skip, copy); | |
600 | ||
601 | to += copy; | |
602 | skip += copy; | |
603 | bytes -= copy; | |
604 | ||
605 | while (bytes) { | |
606 | bvec++; | |
607 | copy = min(bytes, (size_t)bvec->bv_len); | |
608 | memcpy_from_page(to, bvec->bv_page, bvec->bv_offset, copy); | |
609 | skip = copy; | |
610 | to += copy; | |
611 | bytes -= copy; | |
612 | } | |
62a8067a AV |
613 | if (skip == bvec->bv_len) { |
614 | bvec++; | |
615 | skip = 0; | |
616 | } | |
617 | i->count -= wanted; | |
618 | i->nr_segs -= bvec - i->bvec; | |
619 | i->bvec = bvec; | |
620 | i->iov_offset = skip; | |
621 | return wanted; | |
622 | } | |
623 | ||
c35e0248 MW |
624 | static size_t copy_page_to_iter_bvec(struct page *page, size_t offset, |
625 | size_t bytes, struct iov_iter *i) | |
626 | { | |
627 | void *kaddr = kmap_atomic(page); | |
628 | size_t wanted = copy_to_iter_bvec(kaddr + offset, bytes, i); | |
629 | kunmap_atomic(kaddr); | |
630 | return wanted; | |
631 | } | |
632 | ||
633 | static size_t copy_page_from_iter_bvec(struct page *page, size_t offset, | |
634 | size_t bytes, struct iov_iter *i) | |
635 | { | |
636 | void *kaddr = kmap_atomic(page); | |
637 | size_t wanted = copy_from_iter_bvec(kaddr + offset, bytes, i); | |
638 | kunmap_atomic(kaddr); | |
639 | return wanted; | |
640 | } | |
641 | ||
642 | static size_t zero_bvec(size_t bytes, struct iov_iter *i) | |
643 | { | |
644 | size_t skip, copy, wanted; | |
645 | const struct bio_vec *bvec; | |
646 | ||
647 | if (unlikely(bytes > i->count)) | |
648 | bytes = i->count; | |
649 | ||
650 | if (unlikely(!bytes)) | |
651 | return 0; | |
652 | ||
653 | wanted = bytes; | |
654 | bvec = i->bvec; | |
655 | skip = i->iov_offset; | |
656 | copy = min_t(size_t, bytes, bvec->bv_len - skip); | |
657 | ||
658 | memzero_page(bvec->bv_page, skip + bvec->bv_offset, copy); | |
659 | skip += copy; | |
660 | bytes -= copy; | |
661 | while (bytes) { | |
662 | bvec++; | |
663 | copy = min(bytes, (size_t)bvec->bv_len); | |
664 | memzero_page(bvec->bv_page, bvec->bv_offset, copy); | |
665 | skip = copy; | |
666 | bytes -= copy; | |
667 | } | |
668 | if (skip == bvec->bv_len) { | |
669 | bvec++; | |
670 | skip = 0; | |
671 | } | |
672 | i->count -= wanted - bytes; | |
673 | i->nr_segs -= bvec - i->bvec; | |
674 | i->bvec = bvec; | |
675 | i->iov_offset = skip; | |
676 | return wanted - bytes; | |
677 | } | |
678 | ||
62a8067a | 679 | static ssize_t get_pages_bvec(struct iov_iter *i, |
2c80929c | 680 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
681 | size_t *start) |
682 | { | |
683 | const struct bio_vec *bvec = i->bvec; | |
684 | size_t len = bvec->bv_len - i->iov_offset; | |
685 | if (len > i->count) | |
686 | len = i->count; | |
2c80929c MS |
687 | if (len > maxsize) |
688 | len = maxsize; | |
c7f3888a | 689 | /* can't be more than PAGE_SIZE */ |
62a8067a AV |
690 | *start = bvec->bv_offset + i->iov_offset; |
691 | ||
692 | get_page(*pages = bvec->bv_page); | |
693 | ||
694 | return len; | |
695 | } | |
696 | ||
697 | static ssize_t get_pages_alloc_bvec(struct iov_iter *i, | |
698 | struct page ***pages, size_t maxsize, | |
699 | size_t *start) | |
700 | { | |
701 | const struct bio_vec *bvec = i->bvec; | |
702 | size_t len = bvec->bv_len - i->iov_offset; | |
703 | if (len > i->count) | |
704 | len = i->count; | |
705 | if (len > maxsize) | |
706 | len = maxsize; | |
707 | *start = bvec->bv_offset + i->iov_offset; | |
708 | ||
709 | *pages = kmalloc(sizeof(struct page *), GFP_KERNEL); | |
710 | if (!*pages) | |
711 | return -ENOMEM; | |
712 | ||
713 | get_page(**pages = bvec->bv_page); | |
714 | ||
715 | return len; | |
716 | } | |
717 | ||
718 | static int iov_iter_npages_bvec(const struct iov_iter *i, int maxpages) | |
719 | { | |
720 | size_t offset = i->iov_offset; | |
721 | size_t size = i->count; | |
722 | const struct bio_vec *bvec = i->bvec; | |
723 | int npages = 0; | |
724 | int n; | |
725 | ||
726 | for (n = 0; size && n < i->nr_segs; n++, bvec++) { | |
727 | size_t len = bvec->bv_len - offset; | |
728 | offset = 0; | |
729 | if (unlikely(!len)) /* empty segment */ | |
730 | continue; | |
731 | if (len > size) | |
732 | len = size; | |
733 | npages++; | |
734 | if (npages >= maxpages) /* don't bother going further */ | |
735 | return maxpages; | |
736 | size -= len; | |
737 | offset = 0; | |
738 | } | |
739 | return min(npages, maxpages); | |
740 | } | |
741 | ||
742 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, | |
743 | struct iov_iter *i) | |
744 | { | |
745 | if (i->type & ITER_BVEC) | |
746 | return copy_page_to_iter_bvec(page, offset, bytes, i); | |
747 | else | |
748 | return copy_page_to_iter_iovec(page, offset, bytes, i); | |
749 | } | |
750 | EXPORT_SYMBOL(copy_page_to_iter); | |
751 | ||
752 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
753 | struct iov_iter *i) | |
754 | { | |
755 | if (i->type & ITER_BVEC) | |
756 | return copy_page_from_iter_bvec(page, offset, bytes, i); | |
757 | else | |
758 | return copy_page_from_iter_iovec(page, offset, bytes, i); | |
759 | } | |
760 | EXPORT_SYMBOL(copy_page_from_iter); | |
761 | ||
c35e0248 MW |
762 | size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i) |
763 | { | |
764 | if (i->type & ITER_BVEC) | |
765 | return copy_to_iter_bvec(addr, bytes, i); | |
766 | else | |
767 | return copy_to_iter_iovec(addr, bytes, i); | |
768 | } | |
769 | EXPORT_SYMBOL(copy_to_iter); | |
770 | ||
771 | size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) | |
772 | { | |
773 | if (i->type & ITER_BVEC) | |
774 | return copy_from_iter_bvec(addr, bytes, i); | |
775 | else | |
776 | return copy_from_iter_iovec(addr, bytes, i); | |
777 | } | |
778 | EXPORT_SYMBOL(copy_from_iter); | |
779 | ||
780 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) | |
781 | { | |
782 | if (i->type & ITER_BVEC) { | |
783 | return zero_bvec(bytes, i); | |
784 | } else { | |
785 | return zero_iovec(bytes, i); | |
786 | } | |
787 | } | |
788 | EXPORT_SYMBOL(iov_iter_zero); | |
789 | ||
62a8067a AV |
790 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
791 | struct iov_iter *i, unsigned long offset, size_t bytes) | |
792 | { | |
04a31165 AV |
793 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
794 | iterate_all_kinds(i, bytes, v, | |
795 | __copy_from_user_inatomic((p += v.iov_len) - v.iov_len, | |
796 | v.iov_base, v.iov_len), | |
797 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, | |
798 | v.bv_offset, v.bv_len) | |
799 | ) | |
800 | kunmap_atomic(kaddr); | |
801 | return bytes; | |
62a8067a AV |
802 | } |
803 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); | |
804 | ||
805 | void iov_iter_advance(struct iov_iter *i, size_t size) | |
806 | { | |
7ce2a91e | 807 | iterate_and_advance(i, size, v, 0, 0) |
62a8067a AV |
808 | } |
809 | EXPORT_SYMBOL(iov_iter_advance); | |
810 | ||
811 | /* | |
812 | * Return the count of just the current iov_iter segment. | |
813 | */ | |
814 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
815 | { | |
816 | if (i->nr_segs == 1) | |
817 | return i->count; | |
818 | else if (i->type & ITER_BVEC) | |
62a8067a | 819 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
ad0eab92 PM |
820 | else |
821 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
62a8067a AV |
822 | } |
823 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
824 | ||
825 | unsigned long iov_iter_alignment(const struct iov_iter *i) | |
826 | { | |
04a31165 AV |
827 | unsigned long res = 0; |
828 | size_t size = i->count; | |
829 | ||
830 | if (!size) | |
831 | return 0; | |
832 | ||
833 | iterate_all_kinds(i, size, v, | |
834 | (res |= (unsigned long)v.iov_base | v.iov_len, 0), | |
835 | res |= v.bv_offset | v.bv_len | |
836 | ) | |
837 | return res; | |
62a8067a AV |
838 | } |
839 | EXPORT_SYMBOL(iov_iter_alignment); | |
840 | ||
841 | ssize_t iov_iter_get_pages(struct iov_iter *i, | |
2c80929c | 842 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
843 | size_t *start) |
844 | { | |
845 | if (i->type & ITER_BVEC) | |
2c80929c | 846 | return get_pages_bvec(i, pages, maxsize, maxpages, start); |
62a8067a | 847 | else |
2c80929c | 848 | return get_pages_iovec(i, pages, maxsize, maxpages, start); |
62a8067a AV |
849 | } |
850 | EXPORT_SYMBOL(iov_iter_get_pages); | |
851 | ||
852 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, | |
853 | struct page ***pages, size_t maxsize, | |
854 | size_t *start) | |
855 | { | |
856 | if (i->type & ITER_BVEC) | |
857 | return get_pages_alloc_bvec(i, pages, maxsize, start); | |
858 | else | |
859 | return get_pages_alloc_iovec(i, pages, maxsize, start); | |
860 | } | |
861 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
862 | ||
863 | int iov_iter_npages(const struct iov_iter *i, int maxpages) | |
864 | { | |
865 | if (i->type & ITER_BVEC) | |
866 | return iov_iter_npages_bvec(i, maxpages); | |
867 | else | |
868 | return iov_iter_npages_iovec(i, maxpages); | |
869 | } | |
f67da30c | 870 | EXPORT_SYMBOL(iov_iter_npages); |