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