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 | ||
62a8067a | 145 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
146 | struct iov_iter *i) |
147 | { | |
148 | size_t skip, copy, left, wanted; | |
149 | const struct iovec *iov; | |
150 | char __user *buf; | |
151 | void *kaddr, *from; | |
152 | ||
153 | if (unlikely(bytes > i->count)) | |
154 | bytes = i->count; | |
155 | ||
156 | if (unlikely(!bytes)) | |
157 | return 0; | |
158 | ||
159 | wanted = bytes; | |
160 | iov = i->iov; | |
161 | skip = i->iov_offset; | |
162 | buf = iov->iov_base + skip; | |
163 | copy = min(bytes, iov->iov_len - skip); | |
164 | ||
165 | if (!fault_in_pages_writeable(buf, copy)) { | |
166 | kaddr = kmap_atomic(page); | |
167 | from = kaddr + offset; | |
168 | ||
169 | /* first chunk, usually the only one */ | |
170 | left = __copy_to_user_inatomic(buf, from, copy); | |
171 | copy -= left; | |
172 | skip += copy; | |
173 | from += copy; | |
174 | bytes -= copy; | |
175 | ||
176 | while (unlikely(!left && bytes)) { | |
177 | iov++; | |
178 | buf = iov->iov_base; | |
179 | copy = min(bytes, iov->iov_len); | |
180 | left = __copy_to_user_inatomic(buf, from, copy); | |
181 | copy -= left; | |
182 | skip = copy; | |
183 | from += copy; | |
184 | bytes -= copy; | |
185 | } | |
186 | if (likely(!bytes)) { | |
187 | kunmap_atomic(kaddr); | |
188 | goto done; | |
189 | } | |
190 | offset = from - kaddr; | |
191 | buf += copy; | |
192 | kunmap_atomic(kaddr); | |
193 | copy = min(bytes, iov->iov_len - skip); | |
194 | } | |
195 | /* Too bad - revert to non-atomic kmap */ | |
196 | kaddr = kmap(page); | |
197 | from = kaddr + offset; | |
198 | left = __copy_to_user(buf, from, copy); | |
199 | copy -= left; | |
200 | skip += copy; | |
201 | from += copy; | |
202 | bytes -= copy; | |
203 | while (unlikely(!left && bytes)) { | |
204 | iov++; | |
205 | buf = iov->iov_base; | |
206 | copy = min(bytes, iov->iov_len); | |
207 | left = __copy_to_user(buf, from, copy); | |
208 | copy -= left; | |
209 | skip = copy; | |
210 | from += copy; | |
211 | bytes -= copy; | |
212 | } | |
213 | kunmap(page); | |
214 | done: | |
81055e58 AV |
215 | if (skip == iov->iov_len) { |
216 | iov++; | |
217 | skip = 0; | |
218 | } | |
4f18cd31 AV |
219 | i->count -= wanted - bytes; |
220 | i->nr_segs -= iov - i->iov; | |
221 | i->iov = iov; | |
222 | i->iov_offset = skip; | |
223 | return wanted - bytes; | |
224 | } | |
4f18cd31 | 225 | |
62a8067a | 226 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
227 | struct iov_iter *i) |
228 | { | |
229 | size_t skip, copy, left, wanted; | |
230 | const struct iovec *iov; | |
231 | char __user *buf; | |
232 | void *kaddr, *to; | |
233 | ||
234 | if (unlikely(bytes > i->count)) | |
235 | bytes = i->count; | |
236 | ||
237 | if (unlikely(!bytes)) | |
238 | return 0; | |
239 | ||
240 | wanted = bytes; | |
241 | iov = i->iov; | |
242 | skip = i->iov_offset; | |
243 | buf = iov->iov_base + skip; | |
244 | copy = min(bytes, iov->iov_len - skip); | |
245 | ||
246 | if (!fault_in_pages_readable(buf, copy)) { | |
247 | kaddr = kmap_atomic(page); | |
248 | to = kaddr + offset; | |
249 | ||
250 | /* first chunk, usually the only one */ | |
251 | left = __copy_from_user_inatomic(to, buf, copy); | |
252 | copy -= left; | |
253 | skip += copy; | |
254 | to += copy; | |
255 | bytes -= copy; | |
256 | ||
257 | while (unlikely(!left && bytes)) { | |
258 | iov++; | |
259 | buf = iov->iov_base; | |
260 | copy = min(bytes, iov->iov_len); | |
261 | left = __copy_from_user_inatomic(to, buf, copy); | |
262 | copy -= left; | |
263 | skip = copy; | |
264 | to += copy; | |
265 | bytes -= copy; | |
266 | } | |
267 | if (likely(!bytes)) { | |
268 | kunmap_atomic(kaddr); | |
269 | goto done; | |
270 | } | |
271 | offset = to - kaddr; | |
272 | buf += copy; | |
273 | kunmap_atomic(kaddr); | |
274 | copy = min(bytes, iov->iov_len - skip); | |
275 | } | |
276 | /* Too bad - revert to non-atomic kmap */ | |
277 | kaddr = kmap(page); | |
278 | to = kaddr + offset; | |
279 | left = __copy_from_user(to, buf, copy); | |
280 | copy -= left; | |
281 | skip += copy; | |
282 | to += copy; | |
283 | bytes -= copy; | |
284 | while (unlikely(!left && bytes)) { | |
285 | iov++; | |
286 | buf = iov->iov_base; | |
287 | copy = min(bytes, iov->iov_len); | |
288 | left = __copy_from_user(to, buf, copy); | |
289 | copy -= left; | |
290 | skip = copy; | |
291 | to += copy; | |
292 | bytes -= copy; | |
293 | } | |
294 | kunmap(page); | |
295 | done: | |
81055e58 AV |
296 | if (skip == iov->iov_len) { |
297 | iov++; | |
298 | skip = 0; | |
299 | } | |
f0d1bec9 AV |
300 | i->count -= wanted - bytes; |
301 | i->nr_segs -= iov - i->iov; | |
302 | i->iov = iov; | |
303 | i->iov_offset = skip; | |
304 | return wanted - bytes; | |
305 | } | |
f0d1bec9 | 306 | |
4f18cd31 AV |
307 | /* |
308 | * Fault in the first iovec of the given iov_iter, to a maximum length | |
309 | * of bytes. Returns 0 on success, or non-zero if the memory could not be | |
310 | * accessed (ie. because it is an invalid address). | |
311 | * | |
312 | * writev-intensive code may want this to prefault several iovecs -- that | |
313 | * would be possible (callers must not rely on the fact that _only_ the | |
314 | * first iovec will be faulted with the current implementation). | |
315 | */ | |
316 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) | |
317 | { | |
62a8067a AV |
318 | if (!(i->type & ITER_BVEC)) { |
319 | char __user *buf = i->iov->iov_base + i->iov_offset; | |
320 | bytes = min(bytes, i->iov->iov_len - i->iov_offset); | |
321 | return fault_in_pages_readable(buf, bytes); | |
322 | } | |
323 | return 0; | |
4f18cd31 AV |
324 | } |
325 | EXPORT_SYMBOL(iov_iter_fault_in_readable); | |
326 | ||
71d8e532 AV |
327 | void iov_iter_init(struct iov_iter *i, int direction, |
328 | const struct iovec *iov, unsigned long nr_segs, | |
329 | size_t count) | |
330 | { | |
331 | /* It will get better. Eventually... */ | |
332 | if (segment_eq(get_fs(), KERNEL_DS)) | |
62a8067a | 333 | direction |= ITER_KVEC; |
71d8e532 AV |
334 | i->type = direction; |
335 | i->iov = iov; | |
336 | i->nr_segs = nr_segs; | |
337 | i->iov_offset = 0; | |
338 | i->count = count; | |
339 | } | |
340 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 341 | |
62a8067a AV |
342 | static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len) |
343 | { | |
344 | char *from = kmap_atomic(page); | |
345 | memcpy(to, from + offset, len); | |
346 | kunmap_atomic(from); | |
347 | } | |
348 | ||
349 | static void memcpy_to_page(struct page *page, size_t offset, char *from, size_t len) | |
350 | { | |
351 | char *to = kmap_atomic(page); | |
352 | memcpy(to + offset, from, len); | |
353 | kunmap_atomic(to); | |
354 | } | |
355 | ||
c35e0248 MW |
356 | static void memzero_page(struct page *page, size_t offset, size_t len) |
357 | { | |
358 | char *addr = kmap_atomic(page); | |
359 | memset(addr + offset, 0, len); | |
360 | kunmap_atomic(addr); | |
361 | } | |
362 | ||
363 | static size_t copy_to_iter_bvec(void *from, size_t bytes, struct iov_iter *i) | |
62a8067a AV |
364 | { |
365 | size_t skip, copy, wanted; | |
366 | const struct bio_vec *bvec; | |
62a8067a AV |
367 | |
368 | if (unlikely(bytes > i->count)) | |
369 | bytes = i->count; | |
370 | ||
371 | if (unlikely(!bytes)) | |
372 | return 0; | |
373 | ||
374 | wanted = bytes; | |
375 | bvec = i->bvec; | |
376 | skip = i->iov_offset; | |
377 | copy = min_t(size_t, bytes, bvec->bv_len - skip); | |
378 | ||
62a8067a AV |
379 | memcpy_to_page(bvec->bv_page, skip + bvec->bv_offset, from, copy); |
380 | skip += copy; | |
381 | from += copy; | |
382 | bytes -= copy; | |
383 | while (bytes) { | |
384 | bvec++; | |
385 | copy = min(bytes, (size_t)bvec->bv_len); | |
386 | memcpy_to_page(bvec->bv_page, bvec->bv_offset, from, copy); | |
387 | skip = copy; | |
388 | from += copy; | |
389 | bytes -= copy; | |
390 | } | |
62a8067a AV |
391 | if (skip == bvec->bv_len) { |
392 | bvec++; | |
393 | skip = 0; | |
394 | } | |
395 | i->count -= wanted - bytes; | |
396 | i->nr_segs -= bvec - i->bvec; | |
397 | i->bvec = bvec; | |
398 | i->iov_offset = skip; | |
399 | return wanted - bytes; | |
400 | } | |
401 | ||
d271524a | 402 | size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 403 | { |
d271524a AV |
404 | if (i->type & ITER_BVEC) |
405 | return copy_to_iter_bvec(addr, bytes, i); | |
406 | else | |
407 | return copy_to_iter_iovec(addr, bytes, i); | |
c35e0248 | 408 | } |
d271524a | 409 | EXPORT_SYMBOL(copy_to_iter); |
c35e0248 | 410 | |
d271524a | 411 | size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 412 | { |
0dbca9a4 AV |
413 | char *to = addr; |
414 | if (unlikely(bytes > i->count)) | |
415 | bytes = i->count; | |
416 | ||
417 | if (unlikely(!bytes)) | |
418 | return 0; | |
419 | ||
420 | iterate_and_advance(i, bytes, v, | |
421 | __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base, | |
422 | v.iov_len), | |
423 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
424 | v.bv_offset, v.bv_len) | |
425 | ) | |
426 | ||
427 | return bytes; | |
c35e0248 | 428 | } |
d271524a | 429 | EXPORT_SYMBOL(copy_from_iter); |
c35e0248 | 430 | |
62a8067a AV |
431 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
432 | struct iov_iter *i) | |
433 | { | |
d271524a AV |
434 | if (i->type & (ITER_BVEC|ITER_KVEC)) { |
435 | void *kaddr = kmap_atomic(page); | |
436 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); | |
437 | kunmap_atomic(kaddr); | |
438 | return wanted; | |
439 | } else | |
62a8067a AV |
440 | return copy_page_to_iter_iovec(page, offset, bytes, i); |
441 | } | |
442 | EXPORT_SYMBOL(copy_page_to_iter); | |
443 | ||
444 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
445 | struct iov_iter *i) | |
446 | { | |
d271524a AV |
447 | if (i->type & ITER_BVEC) { |
448 | void *kaddr = kmap_atomic(page); | |
449 | size_t wanted = copy_from_iter(kaddr + offset, bytes, i); | |
450 | kunmap_atomic(kaddr); | |
451 | return wanted; | |
452 | } else | |
62a8067a AV |
453 | return copy_page_from_iter_iovec(page, offset, bytes, i); |
454 | } | |
455 | EXPORT_SYMBOL(copy_page_from_iter); | |
456 | ||
c35e0248 MW |
457 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
458 | { | |
8442fa46 AV |
459 | if (unlikely(bytes > i->count)) |
460 | bytes = i->count; | |
461 | ||
462 | if (unlikely(!bytes)) | |
463 | return 0; | |
464 | ||
465 | iterate_and_advance(i, bytes, v, | |
466 | __clear_user(v.iov_base, v.iov_len), | |
467 | memzero_page(v.bv_page, v.bv_offset, v.bv_len) | |
468 | ) | |
469 | ||
470 | return bytes; | |
c35e0248 MW |
471 | } |
472 | EXPORT_SYMBOL(iov_iter_zero); | |
473 | ||
62a8067a AV |
474 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
475 | struct iov_iter *i, unsigned long offset, size_t bytes) | |
476 | { | |
04a31165 AV |
477 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
478 | iterate_all_kinds(i, bytes, v, | |
479 | __copy_from_user_inatomic((p += v.iov_len) - v.iov_len, | |
480 | v.iov_base, v.iov_len), | |
481 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, | |
482 | v.bv_offset, v.bv_len) | |
483 | ) | |
484 | kunmap_atomic(kaddr); | |
485 | return bytes; | |
62a8067a AV |
486 | } |
487 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); | |
488 | ||
489 | void iov_iter_advance(struct iov_iter *i, size_t size) | |
490 | { | |
7ce2a91e | 491 | iterate_and_advance(i, size, v, 0, 0) |
62a8067a AV |
492 | } |
493 | EXPORT_SYMBOL(iov_iter_advance); | |
494 | ||
495 | /* | |
496 | * Return the count of just the current iov_iter segment. | |
497 | */ | |
498 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
499 | { | |
500 | if (i->nr_segs == 1) | |
501 | return i->count; | |
502 | else if (i->type & ITER_BVEC) | |
62a8067a | 503 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
ad0eab92 PM |
504 | else |
505 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
62a8067a AV |
506 | } |
507 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
508 | ||
509 | unsigned long iov_iter_alignment(const struct iov_iter *i) | |
510 | { | |
04a31165 AV |
511 | unsigned long res = 0; |
512 | size_t size = i->count; | |
513 | ||
514 | if (!size) | |
515 | return 0; | |
516 | ||
517 | iterate_all_kinds(i, size, v, | |
518 | (res |= (unsigned long)v.iov_base | v.iov_len, 0), | |
519 | res |= v.bv_offset | v.bv_len | |
520 | ) | |
521 | return res; | |
62a8067a AV |
522 | } |
523 | EXPORT_SYMBOL(iov_iter_alignment); | |
524 | ||
525 | ssize_t iov_iter_get_pages(struct iov_iter *i, | |
2c80929c | 526 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
527 | size_t *start) |
528 | { | |
e5393fae AV |
529 | if (maxsize > i->count) |
530 | maxsize = i->count; | |
531 | ||
532 | if (!maxsize) | |
533 | return 0; | |
534 | ||
535 | iterate_all_kinds(i, maxsize, v, ({ | |
536 | unsigned long addr = (unsigned long)v.iov_base; | |
537 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
538 | int n; | |
539 | int res; | |
540 | ||
541 | if (len > maxpages * PAGE_SIZE) | |
542 | len = maxpages * PAGE_SIZE; | |
543 | addr &= ~(PAGE_SIZE - 1); | |
544 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
545 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages); | |
546 | if (unlikely(res < 0)) | |
547 | return res; | |
548 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
549 | 0;}),({ | |
550 | /* can't be more than PAGE_SIZE */ | |
551 | *start = v.bv_offset; | |
552 | get_page(*pages = v.bv_page); | |
553 | return v.bv_len; | |
554 | }) | |
555 | ) | |
556 | return 0; | |
62a8067a AV |
557 | } |
558 | EXPORT_SYMBOL(iov_iter_get_pages); | |
559 | ||
1b17f1f2 AV |
560 | static struct page **get_pages_array(size_t n) |
561 | { | |
562 | struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL); | |
563 | if (!p) | |
564 | p = vmalloc(n * sizeof(struct page *)); | |
565 | return p; | |
566 | } | |
567 | ||
62a8067a AV |
568 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
569 | struct page ***pages, size_t maxsize, | |
570 | size_t *start) | |
571 | { | |
1b17f1f2 AV |
572 | struct page **p; |
573 | ||
574 | if (maxsize > i->count) | |
575 | maxsize = i->count; | |
576 | ||
577 | if (!maxsize) | |
578 | return 0; | |
579 | ||
580 | iterate_all_kinds(i, maxsize, v, ({ | |
581 | unsigned long addr = (unsigned long)v.iov_base; | |
582 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
583 | int n; | |
584 | int res; | |
585 | ||
586 | addr &= ~(PAGE_SIZE - 1); | |
587 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
588 | p = get_pages_array(n); | |
589 | if (!p) | |
590 | return -ENOMEM; | |
591 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p); | |
592 | if (unlikely(res < 0)) { | |
593 | kvfree(p); | |
594 | return res; | |
595 | } | |
596 | *pages = p; | |
597 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
598 | 0;}),({ | |
599 | /* can't be more than PAGE_SIZE */ | |
600 | *start = v.bv_offset; | |
601 | *pages = p = get_pages_array(1); | |
602 | if (!p) | |
603 | return -ENOMEM; | |
604 | get_page(*p = v.bv_page); | |
605 | return v.bv_len; | |
606 | }) | |
607 | ) | |
608 | return 0; | |
62a8067a AV |
609 | } |
610 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
611 | ||
612 | int iov_iter_npages(const struct iov_iter *i, int maxpages) | |
613 | { | |
e0f2dc40 AV |
614 | size_t size = i->count; |
615 | int npages = 0; | |
616 | ||
617 | if (!size) | |
618 | return 0; | |
619 | ||
620 | iterate_all_kinds(i, size, v, ({ | |
621 | unsigned long p = (unsigned long)v.iov_base; | |
622 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
623 | - p / PAGE_SIZE; | |
624 | if (npages >= maxpages) | |
625 | return maxpages; | |
626 | 0;}),({ | |
627 | npages++; | |
628 | if (npages >= maxpages) | |
629 | return maxpages; | |
630 | }) | |
631 | ) | |
632 | return npages; | |
62a8067a | 633 | } |
f67da30c | 634 | EXPORT_SYMBOL(iov_iter_npages); |