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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 | ||
a280455f AV |
35 | #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ |
36 | size_t wanted = n; \ | |
37 | __p = i->kvec; \ | |
38 | __v.iov_len = min(n, __p->iov_len - skip); \ | |
39 | if (likely(__v.iov_len)) { \ | |
40 | __v.iov_base = __p->iov_base + skip; \ | |
41 | (void)(STEP); \ | |
42 | skip += __v.iov_len; \ | |
43 | n -= __v.iov_len; \ | |
44 | } \ | |
45 | while (unlikely(n)) { \ | |
46 | __p++; \ | |
47 | __v.iov_len = min(n, __p->iov_len); \ | |
48 | if (unlikely(!__v.iov_len)) \ | |
49 | continue; \ | |
50 | __v.iov_base = __p->iov_base; \ | |
51 | (void)(STEP); \ | |
52 | skip = __v.iov_len; \ | |
53 | n -= __v.iov_len; \ | |
54 | } \ | |
55 | n = wanted; \ | |
56 | } | |
57 | ||
04a31165 AV |
58 | #define iterate_bvec(i, n, __v, __p, skip, STEP) { \ |
59 | size_t wanted = n; \ | |
60 | __p = i->bvec; \ | |
61 | __v.bv_len = min_t(size_t, n, __p->bv_len - skip); \ | |
62 | if (likely(__v.bv_len)) { \ | |
63 | __v.bv_page = __p->bv_page; \ | |
64 | __v.bv_offset = __p->bv_offset + skip; \ | |
65 | (void)(STEP); \ | |
66 | skip += __v.bv_len; \ | |
67 | n -= __v.bv_len; \ | |
68 | } \ | |
69 | while (unlikely(n)) { \ | |
70 | __p++; \ | |
71 | __v.bv_len = min_t(size_t, n, __p->bv_len); \ | |
72 | if (unlikely(!__v.bv_len)) \ | |
73 | continue; \ | |
74 | __v.bv_page = __p->bv_page; \ | |
75 | __v.bv_offset = __p->bv_offset; \ | |
76 | (void)(STEP); \ | |
77 | skip = __v.bv_len; \ | |
78 | n -= __v.bv_len; \ | |
79 | } \ | |
80 | n = wanted; \ | |
81 | } | |
82 | ||
a280455f | 83 | #define iterate_all_kinds(i, n, v, I, B, K) { \ |
04a31165 AV |
84 | size_t skip = i->iov_offset; \ |
85 | if (unlikely(i->type & ITER_BVEC)) { \ | |
86 | const struct bio_vec *bvec; \ | |
87 | struct bio_vec v; \ | |
88 | iterate_bvec(i, n, v, bvec, skip, (B)) \ | |
a280455f AV |
89 | } else if (unlikely(i->type & ITER_KVEC)) { \ |
90 | const struct kvec *kvec; \ | |
91 | struct kvec v; \ | |
92 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
04a31165 AV |
93 | } else { \ |
94 | const struct iovec *iov; \ | |
95 | struct iovec v; \ | |
96 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
97 | } \ | |
98 | } | |
99 | ||
a280455f | 100 | #define iterate_and_advance(i, n, v, I, B, K) { \ |
7ce2a91e AV |
101 | size_t skip = i->iov_offset; \ |
102 | if (unlikely(i->type & ITER_BVEC)) { \ | |
103 | const struct bio_vec *bvec; \ | |
104 | struct bio_vec v; \ | |
105 | iterate_bvec(i, n, v, bvec, skip, (B)) \ | |
106 | if (skip == bvec->bv_len) { \ | |
107 | bvec++; \ | |
108 | skip = 0; \ | |
109 | } \ | |
110 | i->nr_segs -= bvec - i->bvec; \ | |
111 | i->bvec = bvec; \ | |
a280455f AV |
112 | } else if (unlikely(i->type & ITER_KVEC)) { \ |
113 | const struct kvec *kvec; \ | |
114 | struct kvec v; \ | |
115 | iterate_kvec(i, n, v, kvec, skip, (K)) \ | |
116 | if (skip == kvec->iov_len) { \ | |
117 | kvec++; \ | |
118 | skip = 0; \ | |
119 | } \ | |
120 | i->nr_segs -= kvec - i->kvec; \ | |
121 | i->kvec = kvec; \ | |
7ce2a91e AV |
122 | } else { \ |
123 | const struct iovec *iov; \ | |
124 | struct iovec v; \ | |
125 | iterate_iovec(i, n, v, iov, skip, (I)) \ | |
126 | if (skip == iov->iov_len) { \ | |
127 | iov++; \ | |
128 | skip = 0; \ | |
129 | } \ | |
130 | i->nr_segs -= iov - i->iov; \ | |
131 | i->iov = iov; \ | |
132 | } \ | |
133 | i->count -= n; \ | |
134 | i->iov_offset = skip; \ | |
135 | } | |
136 | ||
62a8067a | 137 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
4f18cd31 AV |
138 | struct iov_iter *i) |
139 | { | |
140 | size_t skip, copy, left, wanted; | |
141 | const struct iovec *iov; | |
142 | char __user *buf; | |
143 | void *kaddr, *from; | |
144 | ||
145 | if (unlikely(bytes > i->count)) | |
146 | bytes = i->count; | |
147 | ||
148 | if (unlikely(!bytes)) | |
149 | return 0; | |
150 | ||
151 | wanted = bytes; | |
152 | iov = i->iov; | |
153 | skip = i->iov_offset; | |
154 | buf = iov->iov_base + skip; | |
155 | copy = min(bytes, iov->iov_len - skip); | |
156 | ||
157 | if (!fault_in_pages_writeable(buf, copy)) { | |
158 | kaddr = kmap_atomic(page); | |
159 | from = kaddr + offset; | |
160 | ||
161 | /* first chunk, usually the only one */ | |
162 | left = __copy_to_user_inatomic(buf, from, copy); | |
163 | copy -= left; | |
164 | skip += copy; | |
165 | from += copy; | |
166 | bytes -= copy; | |
167 | ||
168 | while (unlikely(!left && bytes)) { | |
169 | iov++; | |
170 | buf = iov->iov_base; | |
171 | copy = min(bytes, iov->iov_len); | |
172 | left = __copy_to_user_inatomic(buf, from, copy); | |
173 | copy -= left; | |
174 | skip = copy; | |
175 | from += copy; | |
176 | bytes -= copy; | |
177 | } | |
178 | if (likely(!bytes)) { | |
179 | kunmap_atomic(kaddr); | |
180 | goto done; | |
181 | } | |
182 | offset = from - kaddr; | |
183 | buf += copy; | |
184 | kunmap_atomic(kaddr); | |
185 | copy = min(bytes, iov->iov_len - skip); | |
186 | } | |
187 | /* Too bad - revert to non-atomic kmap */ | |
188 | kaddr = kmap(page); | |
189 | from = kaddr + offset; | |
190 | left = __copy_to_user(buf, from, copy); | |
191 | copy -= left; | |
192 | skip += copy; | |
193 | from += copy; | |
194 | bytes -= copy; | |
195 | while (unlikely(!left && bytes)) { | |
196 | iov++; | |
197 | buf = iov->iov_base; | |
198 | copy = min(bytes, iov->iov_len); | |
199 | left = __copy_to_user(buf, from, copy); | |
200 | copy -= left; | |
201 | skip = copy; | |
202 | from += copy; | |
203 | bytes -= copy; | |
204 | } | |
205 | kunmap(page); | |
206 | done: | |
81055e58 AV |
207 | if (skip == iov->iov_len) { |
208 | iov++; | |
209 | skip = 0; | |
210 | } | |
4f18cd31 AV |
211 | i->count -= wanted - bytes; |
212 | i->nr_segs -= iov - i->iov; | |
213 | i->iov = iov; | |
214 | i->iov_offset = skip; | |
215 | return wanted - bytes; | |
216 | } | |
4f18cd31 | 217 | |
62a8067a | 218 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
f0d1bec9 AV |
219 | struct iov_iter *i) |
220 | { | |
221 | size_t skip, copy, left, wanted; | |
222 | const struct iovec *iov; | |
223 | char __user *buf; | |
224 | void *kaddr, *to; | |
225 | ||
226 | if (unlikely(bytes > i->count)) | |
227 | bytes = i->count; | |
228 | ||
229 | if (unlikely(!bytes)) | |
230 | return 0; | |
231 | ||
232 | wanted = bytes; | |
233 | iov = i->iov; | |
234 | skip = i->iov_offset; | |
235 | buf = iov->iov_base + skip; | |
236 | copy = min(bytes, iov->iov_len - skip); | |
237 | ||
238 | if (!fault_in_pages_readable(buf, copy)) { | |
239 | kaddr = kmap_atomic(page); | |
240 | to = kaddr + offset; | |
241 | ||
242 | /* first chunk, usually the only one */ | |
243 | left = __copy_from_user_inatomic(to, buf, copy); | |
244 | copy -= left; | |
245 | skip += copy; | |
246 | to += copy; | |
247 | bytes -= copy; | |
248 | ||
249 | while (unlikely(!left && bytes)) { | |
250 | iov++; | |
251 | buf = iov->iov_base; | |
252 | copy = min(bytes, iov->iov_len); | |
253 | left = __copy_from_user_inatomic(to, buf, copy); | |
254 | copy -= left; | |
255 | skip = copy; | |
256 | to += copy; | |
257 | bytes -= copy; | |
258 | } | |
259 | if (likely(!bytes)) { | |
260 | kunmap_atomic(kaddr); | |
261 | goto done; | |
262 | } | |
263 | offset = to - kaddr; | |
264 | buf += copy; | |
265 | kunmap_atomic(kaddr); | |
266 | copy = min(bytes, iov->iov_len - skip); | |
267 | } | |
268 | /* Too bad - revert to non-atomic kmap */ | |
269 | kaddr = kmap(page); | |
270 | to = kaddr + offset; | |
271 | left = __copy_from_user(to, buf, copy); | |
272 | copy -= left; | |
273 | skip += copy; | |
274 | to += copy; | |
275 | bytes -= copy; | |
276 | while (unlikely(!left && bytes)) { | |
277 | iov++; | |
278 | buf = iov->iov_base; | |
279 | copy = min(bytes, iov->iov_len); | |
280 | left = __copy_from_user(to, buf, copy); | |
281 | copy -= left; | |
282 | skip = copy; | |
283 | to += copy; | |
284 | bytes -= copy; | |
285 | } | |
286 | kunmap(page); | |
287 | done: | |
81055e58 AV |
288 | if (skip == iov->iov_len) { |
289 | iov++; | |
290 | skip = 0; | |
291 | } | |
f0d1bec9 AV |
292 | i->count -= wanted - bytes; |
293 | i->nr_segs -= iov - i->iov; | |
294 | i->iov = iov; | |
295 | i->iov_offset = skip; | |
296 | return wanted - bytes; | |
297 | } | |
f0d1bec9 | 298 | |
4f18cd31 AV |
299 | /* |
300 | * Fault in the first iovec of the given iov_iter, to a maximum length | |
301 | * of bytes. Returns 0 on success, or non-zero if the memory could not be | |
302 | * accessed (ie. because it is an invalid address). | |
303 | * | |
304 | * writev-intensive code may want this to prefault several iovecs -- that | |
305 | * would be possible (callers must not rely on the fact that _only_ the | |
306 | * first iovec will be faulted with the current implementation). | |
307 | */ | |
308 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) | |
309 | { | |
a280455f | 310 | if (!(i->type & (ITER_BVEC|ITER_KVEC))) { |
62a8067a AV |
311 | char __user *buf = i->iov->iov_base + i->iov_offset; |
312 | bytes = min(bytes, i->iov->iov_len - i->iov_offset); | |
313 | return fault_in_pages_readable(buf, bytes); | |
314 | } | |
315 | return 0; | |
4f18cd31 AV |
316 | } |
317 | EXPORT_SYMBOL(iov_iter_fault_in_readable); | |
318 | ||
71d8e532 AV |
319 | void iov_iter_init(struct iov_iter *i, int direction, |
320 | const struct iovec *iov, unsigned long nr_segs, | |
321 | size_t count) | |
322 | { | |
323 | /* It will get better. Eventually... */ | |
a280455f | 324 | if (segment_eq(get_fs(), KERNEL_DS)) { |
62a8067a | 325 | direction |= ITER_KVEC; |
a280455f AV |
326 | i->type = direction; |
327 | i->kvec = (struct kvec *)iov; | |
328 | } else { | |
329 | i->type = direction; | |
330 | i->iov = iov; | |
331 | } | |
71d8e532 AV |
332 | i->nr_segs = nr_segs; |
333 | i->iov_offset = 0; | |
334 | i->count = count; | |
335 | } | |
336 | EXPORT_SYMBOL(iov_iter_init); | |
7b2c99d1 | 337 | |
62a8067a AV |
338 | static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len) |
339 | { | |
340 | char *from = kmap_atomic(page); | |
341 | memcpy(to, from + offset, len); | |
342 | kunmap_atomic(from); | |
343 | } | |
344 | ||
345 | static void memcpy_to_page(struct page *page, size_t offset, char *from, size_t len) | |
346 | { | |
347 | char *to = kmap_atomic(page); | |
348 | memcpy(to + offset, from, len); | |
349 | kunmap_atomic(to); | |
350 | } | |
351 | ||
c35e0248 MW |
352 | static void memzero_page(struct page *page, size_t offset, size_t len) |
353 | { | |
354 | char *addr = kmap_atomic(page); | |
355 | memset(addr + offset, 0, len); | |
356 | kunmap_atomic(addr); | |
357 | } | |
358 | ||
3d4d3e48 | 359 | size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i) |
62a8067a | 360 | { |
3d4d3e48 | 361 | char *from = addr; |
62a8067a AV |
362 | if (unlikely(bytes > i->count)) |
363 | bytes = i->count; | |
364 | ||
365 | if (unlikely(!bytes)) | |
366 | return 0; | |
367 | ||
3d4d3e48 AV |
368 | iterate_and_advance(i, bytes, v, |
369 | __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len, | |
370 | v.iov_len), | |
371 | memcpy_to_page(v.bv_page, v.bv_offset, | |
a280455f AV |
372 | (from += v.bv_len) - v.bv_len, v.bv_len), |
373 | memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len) | |
3d4d3e48 | 374 | ) |
62a8067a | 375 | |
3d4d3e48 | 376 | return bytes; |
c35e0248 | 377 | } |
d271524a | 378 | EXPORT_SYMBOL(copy_to_iter); |
c35e0248 | 379 | |
d271524a | 380 | size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
c35e0248 | 381 | { |
0dbca9a4 AV |
382 | char *to = addr; |
383 | if (unlikely(bytes > i->count)) | |
384 | bytes = i->count; | |
385 | ||
386 | if (unlikely(!bytes)) | |
387 | return 0; | |
388 | ||
389 | iterate_and_advance(i, bytes, v, | |
390 | __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base, | |
391 | v.iov_len), | |
392 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, | |
a280455f AV |
393 | v.bv_offset, v.bv_len), |
394 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) | |
0dbca9a4 AV |
395 | ) |
396 | ||
397 | return bytes; | |
c35e0248 | 398 | } |
d271524a | 399 | EXPORT_SYMBOL(copy_from_iter); |
c35e0248 | 400 | |
62a8067a AV |
401 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
402 | struct iov_iter *i) | |
403 | { | |
d271524a AV |
404 | if (i->type & (ITER_BVEC|ITER_KVEC)) { |
405 | void *kaddr = kmap_atomic(page); | |
406 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); | |
407 | kunmap_atomic(kaddr); | |
408 | return wanted; | |
409 | } else | |
62a8067a AV |
410 | return copy_page_to_iter_iovec(page, offset, bytes, i); |
411 | } | |
412 | EXPORT_SYMBOL(copy_page_to_iter); | |
413 | ||
414 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, | |
415 | struct iov_iter *i) | |
416 | { | |
a280455f | 417 | if (i->type & (ITER_BVEC|ITER_KVEC)) { |
d271524a AV |
418 | void *kaddr = kmap_atomic(page); |
419 | size_t wanted = copy_from_iter(kaddr + offset, bytes, i); | |
420 | kunmap_atomic(kaddr); | |
421 | return wanted; | |
422 | } else | |
62a8067a AV |
423 | return copy_page_from_iter_iovec(page, offset, bytes, i); |
424 | } | |
425 | EXPORT_SYMBOL(copy_page_from_iter); | |
426 | ||
c35e0248 MW |
427 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
428 | { | |
8442fa46 AV |
429 | if (unlikely(bytes > i->count)) |
430 | bytes = i->count; | |
431 | ||
432 | if (unlikely(!bytes)) | |
433 | return 0; | |
434 | ||
435 | iterate_and_advance(i, bytes, v, | |
436 | __clear_user(v.iov_base, v.iov_len), | |
a280455f AV |
437 | memzero_page(v.bv_page, v.bv_offset, v.bv_len), |
438 | memset(v.iov_base, 0, v.iov_len) | |
8442fa46 AV |
439 | ) |
440 | ||
441 | return bytes; | |
c35e0248 MW |
442 | } |
443 | EXPORT_SYMBOL(iov_iter_zero); | |
444 | ||
62a8067a AV |
445 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
446 | struct iov_iter *i, unsigned long offset, size_t bytes) | |
447 | { | |
04a31165 AV |
448 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
449 | iterate_all_kinds(i, bytes, v, | |
450 | __copy_from_user_inatomic((p += v.iov_len) - v.iov_len, | |
451 | v.iov_base, v.iov_len), | |
452 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, | |
a280455f AV |
453 | v.bv_offset, v.bv_len), |
454 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) | |
04a31165 AV |
455 | ) |
456 | kunmap_atomic(kaddr); | |
457 | return bytes; | |
62a8067a AV |
458 | } |
459 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); | |
460 | ||
461 | void iov_iter_advance(struct iov_iter *i, size_t size) | |
462 | { | |
a280455f | 463 | iterate_and_advance(i, size, v, 0, 0, 0) |
62a8067a AV |
464 | } |
465 | EXPORT_SYMBOL(iov_iter_advance); | |
466 | ||
467 | /* | |
468 | * Return the count of just the current iov_iter segment. | |
469 | */ | |
470 | size_t iov_iter_single_seg_count(const struct iov_iter *i) | |
471 | { | |
472 | if (i->nr_segs == 1) | |
473 | return i->count; | |
474 | else if (i->type & ITER_BVEC) | |
62a8067a | 475 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
ad0eab92 PM |
476 | else |
477 | return min(i->count, i->iov->iov_len - i->iov_offset); | |
62a8067a AV |
478 | } |
479 | EXPORT_SYMBOL(iov_iter_single_seg_count); | |
480 | ||
481 | unsigned long iov_iter_alignment(const struct iov_iter *i) | |
482 | { | |
04a31165 AV |
483 | unsigned long res = 0; |
484 | size_t size = i->count; | |
485 | ||
486 | if (!size) | |
487 | return 0; | |
488 | ||
489 | iterate_all_kinds(i, size, v, | |
490 | (res |= (unsigned long)v.iov_base | v.iov_len, 0), | |
a280455f AV |
491 | res |= v.bv_offset | v.bv_len, |
492 | res |= (unsigned long)v.iov_base | v.iov_len | |
04a31165 AV |
493 | ) |
494 | return res; | |
62a8067a AV |
495 | } |
496 | EXPORT_SYMBOL(iov_iter_alignment); | |
497 | ||
498 | ssize_t iov_iter_get_pages(struct iov_iter *i, | |
2c80929c | 499 | struct page **pages, size_t maxsize, unsigned maxpages, |
62a8067a AV |
500 | size_t *start) |
501 | { | |
e5393fae AV |
502 | if (maxsize > i->count) |
503 | maxsize = i->count; | |
504 | ||
505 | if (!maxsize) | |
506 | return 0; | |
507 | ||
508 | iterate_all_kinds(i, maxsize, v, ({ | |
509 | unsigned long addr = (unsigned long)v.iov_base; | |
510 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
511 | int n; | |
512 | int res; | |
513 | ||
514 | if (len > maxpages * PAGE_SIZE) | |
515 | len = maxpages * PAGE_SIZE; | |
516 | addr &= ~(PAGE_SIZE - 1); | |
517 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
518 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages); | |
519 | if (unlikely(res < 0)) | |
520 | return res; | |
521 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
522 | 0;}),({ | |
523 | /* can't be more than PAGE_SIZE */ | |
524 | *start = v.bv_offset; | |
525 | get_page(*pages = v.bv_page); | |
526 | return v.bv_len; | |
a280455f AV |
527 | }),({ |
528 | return -EFAULT; | |
e5393fae AV |
529 | }) |
530 | ) | |
531 | return 0; | |
62a8067a AV |
532 | } |
533 | EXPORT_SYMBOL(iov_iter_get_pages); | |
534 | ||
1b17f1f2 AV |
535 | static struct page **get_pages_array(size_t n) |
536 | { | |
537 | struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL); | |
538 | if (!p) | |
539 | p = vmalloc(n * sizeof(struct page *)); | |
540 | return p; | |
541 | } | |
542 | ||
62a8067a AV |
543 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
544 | struct page ***pages, size_t maxsize, | |
545 | size_t *start) | |
546 | { | |
1b17f1f2 AV |
547 | struct page **p; |
548 | ||
549 | if (maxsize > i->count) | |
550 | maxsize = i->count; | |
551 | ||
552 | if (!maxsize) | |
553 | return 0; | |
554 | ||
555 | iterate_all_kinds(i, maxsize, v, ({ | |
556 | unsigned long addr = (unsigned long)v.iov_base; | |
557 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); | |
558 | int n; | |
559 | int res; | |
560 | ||
561 | addr &= ~(PAGE_SIZE - 1); | |
562 | n = DIV_ROUND_UP(len, PAGE_SIZE); | |
563 | p = get_pages_array(n); | |
564 | if (!p) | |
565 | return -ENOMEM; | |
566 | res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p); | |
567 | if (unlikely(res < 0)) { | |
568 | kvfree(p); | |
569 | return res; | |
570 | } | |
571 | *pages = p; | |
572 | return (res == n ? len : res * PAGE_SIZE) - *start; | |
573 | 0;}),({ | |
574 | /* can't be more than PAGE_SIZE */ | |
575 | *start = v.bv_offset; | |
576 | *pages = p = get_pages_array(1); | |
577 | if (!p) | |
578 | return -ENOMEM; | |
579 | get_page(*p = v.bv_page); | |
580 | return v.bv_len; | |
a280455f AV |
581 | }),({ |
582 | return -EFAULT; | |
1b17f1f2 AV |
583 | }) |
584 | ) | |
585 | return 0; | |
62a8067a AV |
586 | } |
587 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); | |
588 | ||
589 | int iov_iter_npages(const struct iov_iter *i, int maxpages) | |
590 | { | |
e0f2dc40 AV |
591 | size_t size = i->count; |
592 | int npages = 0; | |
593 | ||
594 | if (!size) | |
595 | return 0; | |
596 | ||
597 | iterate_all_kinds(i, size, v, ({ | |
598 | unsigned long p = (unsigned long)v.iov_base; | |
599 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
600 | - p / PAGE_SIZE; | |
601 | if (npages >= maxpages) | |
602 | return maxpages; | |
603 | 0;}),({ | |
604 | npages++; | |
605 | if (npages >= maxpages) | |
606 | return maxpages; | |
a280455f AV |
607 | }),({ |
608 | unsigned long p = (unsigned long)v.iov_base; | |
609 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) | |
610 | - p / PAGE_SIZE; | |
611 | if (npages >= maxpages) | |
612 | return maxpages; | |
e0f2dc40 AV |
613 | }) |
614 | ) | |
615 | return npages; | |
62a8067a | 616 | } |
f67da30c | 617 | EXPORT_SYMBOL(iov_iter_npages); |