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1// SPDX-License-Identifier: GPL-2.0-only
2#include <crypto/hash.h>
3#include <linux/export.h>
4#include <linux/bvec.h>
5#include <linux/uio.h>
6#include <linux/pagemap.h>
7#include <linux/slab.h>
8#include <linux/vmalloc.h>
9#include <linux/splice.h>
10#include <net/checksum.h>
11#include <linux/scatterlist.h>
12#include <linux/instrumented.h>
13
14#define PIPE_PARANOIA /* for now */
15
16#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
17 size_t left; \
18 size_t wanted = n; \
19 __p = i->iov; \
20 __v.iov_len = min(n, __p->iov_len - skip); \
21 if (likely(__v.iov_len)) { \
22 __v.iov_base = __p->iov_base + skip; \
23 left = (STEP); \
24 __v.iov_len -= left; \
25 skip += __v.iov_len; \
26 n -= __v.iov_len; \
27 } else { \
28 left = 0; \
29 } \
30 while (unlikely(!left && n)) { \
31 __p++; \
32 __v.iov_len = min(n, __p->iov_len); \
33 if (unlikely(!__v.iov_len)) \
34 continue; \
35 __v.iov_base = __p->iov_base; \
36 left = (STEP); \
37 __v.iov_len -= left; \
38 skip = __v.iov_len; \
39 n -= __v.iov_len; \
40 } \
41 n = wanted - n; \
42}
43
44#define iterate_kvec(i, n, __v, __p, skip, STEP) { \
45 size_t wanted = n; \
46 __p = i->kvec; \
47 __v.iov_len = min(n, __p->iov_len - skip); \
48 if (likely(__v.iov_len)) { \
49 __v.iov_base = __p->iov_base + skip; \
50 (void)(STEP); \
51 skip += __v.iov_len; \
52 n -= __v.iov_len; \
53 } \
54 while (unlikely(n)) { \
55 __p++; \
56 __v.iov_len = min(n, __p->iov_len); \
57 if (unlikely(!__v.iov_len)) \
58 continue; \
59 __v.iov_base = __p->iov_base; \
60 (void)(STEP); \
61 skip = __v.iov_len; \
62 n -= __v.iov_len; \
63 } \
64 n = wanted; \
65}
66
67#define iterate_bvec(i, n, __v, __bi, skip, STEP) { \
68 struct bvec_iter __start; \
69 __start.bi_size = n; \
70 __start.bi_bvec_done = skip; \
71 __start.bi_idx = 0; \
72 for_each_bvec(__v, i->bvec, __bi, __start) { \
73 if (!__v.bv_len) \
74 continue; \
75 (void)(STEP); \
76 } \
77}
78
79#define iterate_all_kinds(i, n, v, I, B, K) { \
80 if (likely(n)) { \
81 size_t skip = i->iov_offset; \
82 if (unlikely(i->type & ITER_BVEC)) { \
83 struct bio_vec v; \
84 struct bvec_iter __bi; \
85 iterate_bvec(i, n, v, __bi, skip, (B)) \
86 } else if (unlikely(i->type & ITER_KVEC)) { \
87 const struct kvec *kvec; \
88 struct kvec v; \
89 iterate_kvec(i, n, v, kvec, skip, (K)) \
90 } else if (unlikely(i->type & ITER_DISCARD)) { \
91 } else { \
92 const struct iovec *iov; \
93 struct iovec v; \
94 iterate_iovec(i, n, v, iov, skip, (I)) \
95 } \
96 } \
97}
98
99#define iterate_and_advance(i, n, v, I, B, K) { \
100 if (unlikely(i->count < n)) \
101 n = i->count; \
102 if (i->count) { \
103 size_t skip = i->iov_offset; \
104 if (unlikely(i->type & ITER_BVEC)) { \
105 const struct bio_vec *bvec = i->bvec; \
106 struct bio_vec v; \
107 struct bvec_iter __bi; \
108 iterate_bvec(i, n, v, __bi, skip, (B)) \
109 i->bvec = __bvec_iter_bvec(i->bvec, __bi); \
110 i->nr_segs -= i->bvec - bvec; \
111 skip = __bi.bi_bvec_done; \
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; \
122 } else if (unlikely(i->type & ITER_DISCARD)) { \
123 skip += n; \
124 } else { \
125 const struct iovec *iov; \
126 struct iovec v; \
127 iterate_iovec(i, n, v, iov, skip, (I)) \
128 if (skip == iov->iov_len) { \
129 iov++; \
130 skip = 0; \
131 } \
132 i->nr_segs -= iov - i->iov; \
133 i->iov = iov; \
134 } \
135 i->count -= n; \
136 i->iov_offset = skip; \
137 } \
138}
139
140static int copyout(void __user *to, const void *from, size_t n)
141{
142 if (access_ok(to, n)) {
143 instrument_copy_to_user(to, from, n);
144 n = raw_copy_to_user(to, from, n);
145 }
146 return n;
147}
148
149static int copyin(void *to, const void __user *from, size_t n)
150{
151 if (access_ok(from, n)) {
152 instrument_copy_from_user(to, from, n);
153 n = raw_copy_from_user(to, from, n);
154 }
155 return n;
156}
157
158static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
159 struct iov_iter *i)
160{
161 size_t skip, copy, left, wanted;
162 const struct iovec *iov;
163 char __user *buf;
164 void *kaddr, *from;
165
166 if (unlikely(bytes > i->count))
167 bytes = i->count;
168
169 if (unlikely(!bytes))
170 return 0;
171
172 might_fault();
173 wanted = bytes;
174 iov = i->iov;
175 skip = i->iov_offset;
176 buf = iov->iov_base + skip;
177 copy = min(bytes, iov->iov_len - skip);
178
179 if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) {
180 kaddr = kmap_atomic(page);
181 from = kaddr + offset;
182
183 /* first chunk, usually the only one */
184 left = copyout(buf, from, copy);
185 copy -= left;
186 skip += copy;
187 from += copy;
188 bytes -= copy;
189
190 while (unlikely(!left && bytes)) {
191 iov++;
192 buf = iov->iov_base;
193 copy = min(bytes, iov->iov_len);
194 left = copyout(buf, from, copy);
195 copy -= left;
196 skip = copy;
197 from += copy;
198 bytes -= copy;
199 }
200 if (likely(!bytes)) {
201 kunmap_atomic(kaddr);
202 goto done;
203 }
204 offset = from - kaddr;
205 buf += copy;
206 kunmap_atomic(kaddr);
207 copy = min(bytes, iov->iov_len - skip);
208 }
209 /* Too bad - revert to non-atomic kmap */
210
211 kaddr = kmap(page);
212 from = kaddr + offset;
213 left = copyout(buf, from, copy);
214 copy -= left;
215 skip += copy;
216 from += copy;
217 bytes -= copy;
218 while (unlikely(!left && bytes)) {
219 iov++;
220 buf = iov->iov_base;
221 copy = min(bytes, iov->iov_len);
222 left = copyout(buf, from, copy);
223 copy -= left;
224 skip = copy;
225 from += copy;
226 bytes -= copy;
227 }
228 kunmap(page);
229
230done:
231 if (skip == iov->iov_len) {
232 iov++;
233 skip = 0;
234 }
235 i->count -= wanted - bytes;
236 i->nr_segs -= iov - i->iov;
237 i->iov = iov;
238 i->iov_offset = skip;
239 return wanted - bytes;
240}
241
242static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
243 struct iov_iter *i)
244{
245 size_t skip, copy, left, wanted;
246 const struct iovec *iov;
247 char __user *buf;
248 void *kaddr, *to;
249
250 if (unlikely(bytes > i->count))
251 bytes = i->count;
252
253 if (unlikely(!bytes))
254 return 0;
255
256 might_fault();
257 wanted = bytes;
258 iov = i->iov;
259 skip = i->iov_offset;
260 buf = iov->iov_base + skip;
261 copy = min(bytes, iov->iov_len - skip);
262
263 if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) {
264 kaddr = kmap_atomic(page);
265 to = kaddr + offset;
266
267 /* first chunk, usually the only one */
268 left = copyin(to, buf, copy);
269 copy -= left;
270 skip += copy;
271 to += copy;
272 bytes -= copy;
273
274 while (unlikely(!left && bytes)) {
275 iov++;
276 buf = iov->iov_base;
277 copy = min(bytes, iov->iov_len);
278 left = copyin(to, buf, copy);
279 copy -= left;
280 skip = copy;
281 to += copy;
282 bytes -= copy;
283 }
284 if (likely(!bytes)) {
285 kunmap_atomic(kaddr);
286 goto done;
287 }
288 offset = to - kaddr;
289 buf += copy;
290 kunmap_atomic(kaddr);
291 copy = min(bytes, iov->iov_len - skip);
292 }
293 /* Too bad - revert to non-atomic kmap */
294
295 kaddr = kmap(page);
296 to = kaddr + offset;
297 left = copyin(to, buf, copy);
298 copy -= left;
299 skip += copy;
300 to += copy;
301 bytes -= copy;
302 while (unlikely(!left && bytes)) {
303 iov++;
304 buf = iov->iov_base;
305 copy = min(bytes, iov->iov_len);
306 left = copyin(to, buf, copy);
307 copy -= left;
308 skip = copy;
309 to += copy;
310 bytes -= copy;
311 }
312 kunmap(page);
313
314done:
315 if (skip == iov->iov_len) {
316 iov++;
317 skip = 0;
318 }
319 i->count -= wanted - bytes;
320 i->nr_segs -= iov - i->iov;
321 i->iov = iov;
322 i->iov_offset = skip;
323 return wanted - bytes;
324}
325
326#ifdef PIPE_PARANOIA
327static bool sanity(const struct iov_iter *i)
328{
329 struct pipe_inode_info *pipe = i->pipe;
330 unsigned int p_head = pipe->head;
331 unsigned int p_tail = pipe->tail;
332 unsigned int p_mask = pipe->ring_size - 1;
333 unsigned int p_occupancy = pipe_occupancy(p_head, p_tail);
334 unsigned int i_head = i->head;
335 unsigned int idx;
336
337 if (i->iov_offset) {
338 struct pipe_buffer *p;
339 if (unlikely(p_occupancy == 0))
340 goto Bad; // pipe must be non-empty
341 if (unlikely(i_head != p_head - 1))
342 goto Bad; // must be at the last buffer...
343
344 p = &pipe->bufs[i_head & p_mask];
345 if (unlikely(p->offset + p->len != i->iov_offset))
346 goto Bad; // ... at the end of segment
347 } else {
348 if (i_head != p_head)
349 goto Bad; // must be right after the last buffer
350 }
351 return true;
352Bad:
353 printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset);
354 printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n",
355 p_head, p_tail, pipe->ring_size);
356 for (idx = 0; idx < pipe->ring_size; idx++)
357 printk(KERN_ERR "[%p %p %d %d]\n",
358 pipe->bufs[idx].ops,
359 pipe->bufs[idx].page,
360 pipe->bufs[idx].offset,
361 pipe->bufs[idx].len);
362 WARN_ON(1);
363 return false;
364}
365#else
366#define sanity(i) true
367#endif
368
369static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes,
370 struct iov_iter *i)
371{
372 struct pipe_inode_info *pipe = i->pipe;
373 struct pipe_buffer *buf;
374 unsigned int p_tail = pipe->tail;
375 unsigned int p_mask = pipe->ring_size - 1;
376 unsigned int i_head = i->head;
377 size_t off;
378
379 if (unlikely(bytes > i->count))
380 bytes = i->count;
381
382 if (unlikely(!bytes))
383 return 0;
384
385 if (!sanity(i))
386 return 0;
387
388 off = i->iov_offset;
389 buf = &pipe->bufs[i_head & p_mask];
390 if (off) {
391 if (offset == off && buf->page == page) {
392 /* merge with the last one */
393 buf->len += bytes;
394 i->iov_offset += bytes;
395 goto out;
396 }
397 i_head++;
398 buf = &pipe->bufs[i_head & p_mask];
399 }
400 if (pipe_full(i_head, p_tail, pipe->max_usage))
401 return 0;
402
403 buf->ops = &page_cache_pipe_buf_ops;
404 get_page(page);
405 buf->page = page;
406 buf->offset = offset;
407 buf->len = bytes;
408
409 pipe->head = i_head + 1;
410 i->iov_offset = offset + bytes;
411 i->head = i_head;
412out:
413 i->count -= bytes;
414 return bytes;
415}
416
417/*
418 * Fault in one or more iovecs of the given iov_iter, to a maximum length of
419 * bytes. For each iovec, fault in each page that constitutes the iovec.
420 *
421 * Return 0 on success, or non-zero if the memory could not be accessed (i.e.
422 * because it is an invalid address).
423 */
424int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
425{
426 size_t skip = i->iov_offset;
427 const struct iovec *iov;
428 int err;
429 struct iovec v;
430
431 if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
432 iterate_iovec(i, bytes, v, iov, skip, ({
433 err = fault_in_pages_readable(v.iov_base, v.iov_len);
434 if (unlikely(err))
435 return err;
436 0;}))
437 }
438 return 0;
439}
440EXPORT_SYMBOL(iov_iter_fault_in_readable);
441
442void iov_iter_init(struct iov_iter *i, unsigned int direction,
443 const struct iovec *iov, unsigned long nr_segs,
444 size_t count)
445{
446 WARN_ON(direction & ~(READ | WRITE));
447 direction &= READ | WRITE;
448
449 /* It will get better. Eventually... */
450 if (uaccess_kernel()) {
451 i->type = ITER_KVEC | direction;
452 i->kvec = (struct kvec *)iov;
453 } else {
454 i->type = ITER_IOVEC | direction;
455 i->iov = iov;
456 }
457 i->nr_segs = nr_segs;
458 i->iov_offset = 0;
459 i->count = count;
460}
461EXPORT_SYMBOL(iov_iter_init);
462
463static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
464{
465 char *from = kmap_atomic(page);
466 memcpy(to, from + offset, len);
467 kunmap_atomic(from);
468}
469
470static void memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len)
471{
472 char *to = kmap_atomic(page);
473 memcpy(to + offset, from, len);
474 kunmap_atomic(to);
475}
476
477static void memzero_page(struct page *page, size_t offset, size_t len)
478{
479 char *addr = kmap_atomic(page);
480 memset(addr + offset, 0, len);
481 kunmap_atomic(addr);
482}
483
484static inline bool allocated(struct pipe_buffer *buf)
485{
486 return buf->ops == &default_pipe_buf_ops;
487}
488
489static inline void data_start(const struct iov_iter *i,
490 unsigned int *iter_headp, size_t *offp)
491{
492 unsigned int p_mask = i->pipe->ring_size - 1;
493 unsigned int iter_head = i->head;
494 size_t off = i->iov_offset;
495
496 if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) ||
497 off == PAGE_SIZE)) {
498 iter_head++;
499 off = 0;
500 }
501 *iter_headp = iter_head;
502 *offp = off;
503}
504
505static size_t push_pipe(struct iov_iter *i, size_t size,
506 int *iter_headp, size_t *offp)
507{
508 struct pipe_inode_info *pipe = i->pipe;
509 unsigned int p_tail = pipe->tail;
510 unsigned int p_mask = pipe->ring_size - 1;
511 unsigned int iter_head;
512 size_t off;
513 ssize_t left;
514
515 if (unlikely(size > i->count))
516 size = i->count;
517 if (unlikely(!size))
518 return 0;
519
520 left = size;
521 data_start(i, &iter_head, &off);
522 *iter_headp = iter_head;
523 *offp = off;
524 if (off) {
525 left -= PAGE_SIZE - off;
526 if (left <= 0) {
527 pipe->bufs[iter_head & p_mask].len += size;
528 return size;
529 }
530 pipe->bufs[iter_head & p_mask].len = PAGE_SIZE;
531 iter_head++;
532 }
533 while (!pipe_full(iter_head, p_tail, pipe->max_usage)) {
534 struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask];
535 struct page *page = alloc_page(GFP_USER);
536 if (!page)
537 break;
538
539 buf->ops = &default_pipe_buf_ops;
540 buf->page = page;
541 buf->offset = 0;
542 buf->len = min_t(ssize_t, left, PAGE_SIZE);
543 left -= buf->len;
544 iter_head++;
545 pipe->head = iter_head;
546
547 if (left == 0)
548 return size;
549 }
550 return size - left;
551}
552
553static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
554 struct iov_iter *i)
555{
556 struct pipe_inode_info *pipe = i->pipe;
557 unsigned int p_mask = pipe->ring_size - 1;
558 unsigned int i_head;
559 size_t n, off;
560
561 if (!sanity(i))
562 return 0;
563
564 bytes = n = push_pipe(i, bytes, &i_head, &off);
565 if (unlikely(!n))
566 return 0;
567 do {
568 size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
569 memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk);
570 i->head = i_head;
571 i->iov_offset = off + chunk;
572 n -= chunk;
573 addr += chunk;
574 off = 0;
575 i_head++;
576 } while (n);
577 i->count -= bytes;
578 return bytes;
579}
580
581static __wsum csum_and_memcpy(void *to, const void *from, size_t len,
582 __wsum sum, size_t off)
583{
584 __wsum next = csum_partial_copy_nocheck(from, to, len, 0);
585 return csum_block_add(sum, next, off);
586}
587
588static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes,
589 __wsum *csum, struct iov_iter *i)
590{
591 struct pipe_inode_info *pipe = i->pipe;
592 unsigned int p_mask = pipe->ring_size - 1;
593 unsigned int i_head;
594 size_t n, r;
595 size_t off = 0;
596 __wsum sum = *csum;
597
598 if (!sanity(i))
599 return 0;
600
601 bytes = n = push_pipe(i, bytes, &i_head, &r);
602 if (unlikely(!n))
603 return 0;
604 do {
605 size_t chunk = min_t(size_t, n, PAGE_SIZE - r);
606 char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page);
607 sum = csum_and_memcpy(p + r, addr, chunk, sum, off);
608 kunmap_atomic(p);
609 i->head = i_head;
610 i->iov_offset = r + chunk;
611 n -= chunk;
612 off += chunk;
613 addr += chunk;
614 r = 0;
615 i_head++;
616 } while (n);
617 i->count -= bytes;
618 *csum = sum;
619 return bytes;
620}
621
622size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
623{
624 const char *from = addr;
625 if (unlikely(iov_iter_is_pipe(i)))
626 return copy_pipe_to_iter(addr, bytes, i);
627 if (iter_is_iovec(i))
628 might_fault();
629 iterate_and_advance(i, bytes, v,
630 copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len),
631 memcpy_to_page(v.bv_page, v.bv_offset,
632 (from += v.bv_len) - v.bv_len, v.bv_len),
633 memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)
634 )
635
636 return bytes;
637}
638EXPORT_SYMBOL(_copy_to_iter);
639
640#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
641static int copyout_mcsafe(void __user *to, const void *from, size_t n)
642{
643 if (access_ok(to, n)) {
644 instrument_copy_to_user(to, from, n);
645 n = copy_to_user_mcsafe((__force void *) to, from, n);
646 }
647 return n;
648}
649
650static unsigned long memcpy_mcsafe_to_page(struct page *page, size_t offset,
651 const char *from, size_t len)
652{
653 unsigned long ret;
654 char *to;
655
656 to = kmap_atomic(page);
657 ret = memcpy_mcsafe(to + offset, from, len);
658 kunmap_atomic(to);
659
660 return ret;
661}
662
663static size_t copy_pipe_to_iter_mcsafe(const void *addr, size_t bytes,
664 struct iov_iter *i)
665{
666 struct pipe_inode_info *pipe = i->pipe;
667 unsigned int p_mask = pipe->ring_size - 1;
668 unsigned int i_head;
669 size_t n, off, xfer = 0;
670
671 if (!sanity(i))
672 return 0;
673
674 bytes = n = push_pipe(i, bytes, &i_head, &off);
675 if (unlikely(!n))
676 return 0;
677 do {
678 size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
679 unsigned long rem;
680
681 rem = memcpy_mcsafe_to_page(pipe->bufs[i_head & p_mask].page,
682 off, addr, chunk);
683 i->head = i_head;
684 i->iov_offset = off + chunk - rem;
685 xfer += chunk - rem;
686 if (rem)
687 break;
688 n -= chunk;
689 addr += chunk;
690 off = 0;
691 i_head++;
692 } while (n);
693 i->count -= xfer;
694 return xfer;
695}
696
697/**
698 * _copy_to_iter_mcsafe - copy to user with source-read error exception handling
699 * @addr: source kernel address
700 * @bytes: total transfer length
701 * @iter: destination iterator
702 *
703 * The pmem driver arranges for filesystem-dax to use this facility via
704 * dax_copy_to_iter() for protecting read/write to persistent memory.
705 * Unless / until an architecture can guarantee identical performance
706 * between _copy_to_iter_mcsafe() and _copy_to_iter() it would be a
707 * performance regression to switch more users to the mcsafe version.
708 *
709 * Otherwise, the main differences between this and typical _copy_to_iter().
710 *
711 * * Typical tail/residue handling after a fault retries the copy
712 * byte-by-byte until the fault happens again. Re-triggering machine
713 * checks is potentially fatal so the implementation uses source
714 * alignment and poison alignment assumptions to avoid re-triggering
715 * hardware exceptions.
716 *
717 * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies.
718 * Compare to copy_to_iter() where only ITER_IOVEC attempts might return
719 * a short copy.
720 *
721 * See MCSAFE_TEST for self-test.
722 */
723size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i)
724{
725 const char *from = addr;
726 unsigned long rem, curr_addr, s_addr = (unsigned long) addr;
727
728 if (unlikely(iov_iter_is_pipe(i)))
729 return copy_pipe_to_iter_mcsafe(addr, bytes, i);
730 if (iter_is_iovec(i))
731 might_fault();
732 iterate_and_advance(i, bytes, v,
733 copyout_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len),
734 ({
735 rem = memcpy_mcsafe_to_page(v.bv_page, v.bv_offset,
736 (from += v.bv_len) - v.bv_len, v.bv_len);
737 if (rem) {
738 curr_addr = (unsigned long) from;
739 bytes = curr_addr - s_addr - rem;
740 return bytes;
741 }
742 }),
743 ({
744 rem = memcpy_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len,
745 v.iov_len);
746 if (rem) {
747 curr_addr = (unsigned long) from;
748 bytes = curr_addr - s_addr - rem;
749 return bytes;
750 }
751 })
752 )
753
754 return bytes;
755}
756EXPORT_SYMBOL_GPL(_copy_to_iter_mcsafe);
757#endif /* CONFIG_ARCH_HAS_UACCESS_MCSAFE */
758
759size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
760{
761 char *to = addr;
762 if (unlikely(iov_iter_is_pipe(i))) {
763 WARN_ON(1);
764 return 0;
765 }
766 if (iter_is_iovec(i))
767 might_fault();
768 iterate_and_advance(i, bytes, v,
769 copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),
770 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
771 v.bv_offset, v.bv_len),
772 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
773 )
774
775 return bytes;
776}
777EXPORT_SYMBOL(_copy_from_iter);
778
779bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
780{
781 char *to = addr;
782 if (unlikely(iov_iter_is_pipe(i))) {
783 WARN_ON(1);
784 return false;
785 }
786 if (unlikely(i->count < bytes))
787 return false;
788
789 if (iter_is_iovec(i))
790 might_fault();
791 iterate_all_kinds(i, bytes, v, ({
792 if (copyin((to += v.iov_len) - v.iov_len,
793 v.iov_base, v.iov_len))
794 return false;
795 0;}),
796 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
797 v.bv_offset, v.bv_len),
798 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
799 )
800
801 iov_iter_advance(i, bytes);
802 return true;
803}
804EXPORT_SYMBOL(_copy_from_iter_full);
805
806size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
807{
808 char *to = addr;
809 if (unlikely(iov_iter_is_pipe(i))) {
810 WARN_ON(1);
811 return 0;
812 }
813 iterate_and_advance(i, bytes, v,
814 __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len,
815 v.iov_base, v.iov_len),
816 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
817 v.bv_offset, v.bv_len),
818 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
819 )
820
821 return bytes;
822}
823EXPORT_SYMBOL(_copy_from_iter_nocache);
824
825#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
826/**
827 * _copy_from_iter_flushcache - write destination through cpu cache
828 * @addr: destination kernel address
829 * @bytes: total transfer length
830 * @iter: source iterator
831 *
832 * The pmem driver arranges for filesystem-dax to use this facility via
833 * dax_copy_from_iter() for ensuring that writes to persistent memory
834 * are flushed through the CPU cache. It is differentiated from
835 * _copy_from_iter_nocache() in that guarantees all data is flushed for
836 * all iterator types. The _copy_from_iter_nocache() only attempts to
837 * bypass the cache for the ITER_IOVEC case, and on some archs may use
838 * instructions that strand dirty-data in the cache.
839 */
840size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
841{
842 char *to = addr;
843 if (unlikely(iov_iter_is_pipe(i))) {
844 WARN_ON(1);
845 return 0;
846 }
847 iterate_and_advance(i, bytes, v,
848 __copy_from_user_flushcache((to += v.iov_len) - v.iov_len,
849 v.iov_base, v.iov_len),
850 memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page,
851 v.bv_offset, v.bv_len),
852 memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base,
853 v.iov_len)
854 )
855
856 return bytes;
857}
858EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache);
859#endif
860
861bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
862{
863 char *to = addr;
864 if (unlikely(iov_iter_is_pipe(i))) {
865 WARN_ON(1);
866 return false;
867 }
868 if (unlikely(i->count < bytes))
869 return false;
870 iterate_all_kinds(i, bytes, v, ({
871 if (__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len,
872 v.iov_base, v.iov_len))
873 return false;
874 0;}),
875 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
876 v.bv_offset, v.bv_len),
877 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
878 )
879
880 iov_iter_advance(i, bytes);
881 return true;
882}
883EXPORT_SYMBOL(_copy_from_iter_full_nocache);
884
885static inline bool page_copy_sane(struct page *page, size_t offset, size_t n)
886{
887 struct page *head;
888 size_t v = n + offset;
889
890 /*
891 * The general case needs to access the page order in order
892 * to compute the page size.
893 * However, we mostly deal with order-0 pages and thus can
894 * avoid a possible cache line miss for requests that fit all
895 * page orders.
896 */
897 if (n <= v && v <= PAGE_SIZE)
898 return true;
899
900 head = compound_head(page);
901 v += (page - head) << PAGE_SHIFT;
902
903 if (likely(n <= v && v <= (page_size(head))))
904 return true;
905 WARN_ON(1);
906 return false;
907}
908
909size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
910 struct iov_iter *i)
911{
912 if (unlikely(!page_copy_sane(page, offset, bytes)))
913 return 0;
914 if (i->type & (ITER_BVEC|ITER_KVEC)) {
915 void *kaddr = kmap_atomic(page);
916 size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
917 kunmap_atomic(kaddr);
918 return wanted;
919 } else if (unlikely(iov_iter_is_discard(i)))
920 return bytes;
921 else if (likely(!iov_iter_is_pipe(i)))
922 return copy_page_to_iter_iovec(page, offset, bytes, i);
923 else
924 return copy_page_to_iter_pipe(page, offset, bytes, i);
925}
926EXPORT_SYMBOL(copy_page_to_iter);
927
928size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
929 struct iov_iter *i)
930{
931 if (unlikely(!page_copy_sane(page, offset, bytes)))
932 return 0;
933 if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
934 WARN_ON(1);
935 return 0;
936 }
937 if (i->type & (ITER_BVEC|ITER_KVEC)) {
938 void *kaddr = kmap_atomic(page);
939 size_t wanted = _copy_from_iter(kaddr + offset, bytes, i);
940 kunmap_atomic(kaddr);
941 return wanted;
942 } else
943 return copy_page_from_iter_iovec(page, offset, bytes, i);
944}
945EXPORT_SYMBOL(copy_page_from_iter);
946
947static size_t pipe_zero(size_t bytes, struct iov_iter *i)
948{
949 struct pipe_inode_info *pipe = i->pipe;
950 unsigned int p_mask = pipe->ring_size - 1;
951 unsigned int i_head;
952 size_t n, off;
953
954 if (!sanity(i))
955 return 0;
956
957 bytes = n = push_pipe(i, bytes, &i_head, &off);
958 if (unlikely(!n))
959 return 0;
960
961 do {
962 size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
963 memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk);
964 i->head = i_head;
965 i->iov_offset = off + chunk;
966 n -= chunk;
967 off = 0;
968 i_head++;
969 } while (n);
970 i->count -= bytes;
971 return bytes;
972}
973
974size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
975{
976 if (unlikely(iov_iter_is_pipe(i)))
977 return pipe_zero(bytes, i);
978 iterate_and_advance(i, bytes, v,
979 clear_user(v.iov_base, v.iov_len),
980 memzero_page(v.bv_page, v.bv_offset, v.bv_len),
981 memset(v.iov_base, 0, v.iov_len)
982 )
983
984 return bytes;
985}
986EXPORT_SYMBOL(iov_iter_zero);
987
988size_t iov_iter_copy_from_user_atomic(struct page *page,
989 struct iov_iter *i, unsigned long offset, size_t bytes)
990{
991 char *kaddr = kmap_atomic(page), *p = kaddr + offset;
992 if (unlikely(!page_copy_sane(page, offset, bytes))) {
993 kunmap_atomic(kaddr);
994 return 0;
995 }
996 if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
997 kunmap_atomic(kaddr);
998 WARN_ON(1);
999 return 0;
1000 }
1001 iterate_all_kinds(i, bytes, v,
1002 copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),
1003 memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
1004 v.bv_offset, v.bv_len),
1005 memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
1006 )
1007 kunmap_atomic(kaddr);
1008 return bytes;
1009}
1010EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
1011
1012static inline void pipe_truncate(struct iov_iter *i)
1013{
1014 struct pipe_inode_info *pipe = i->pipe;
1015 unsigned int p_tail = pipe->tail;
1016 unsigned int p_head = pipe->head;
1017 unsigned int p_mask = pipe->ring_size - 1;
1018
1019 if (!pipe_empty(p_head, p_tail)) {
1020 struct pipe_buffer *buf;
1021 unsigned int i_head = i->head;
1022 size_t off = i->iov_offset;
1023
1024 if (off) {
1025 buf = &pipe->bufs[i_head & p_mask];
1026 buf->len = off - buf->offset;
1027 i_head++;
1028 }
1029 while (p_head != i_head) {
1030 p_head--;
1031 pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]);
1032 }
1033
1034 pipe->head = p_head;
1035 }
1036}
1037
1038static void pipe_advance(struct iov_iter *i, size_t size)
1039{
1040 struct pipe_inode_info *pipe = i->pipe;
1041 if (unlikely(i->count < size))
1042 size = i->count;
1043 if (size) {
1044 struct pipe_buffer *buf;
1045 unsigned int p_mask = pipe->ring_size - 1;
1046 unsigned int i_head = i->head;
1047 size_t off = i->iov_offset, left = size;
1048
1049 if (off) /* make it relative to the beginning of buffer */
1050 left += off - pipe->bufs[i_head & p_mask].offset;
1051 while (1) {
1052 buf = &pipe->bufs[i_head & p_mask];
1053 if (left <= buf->len)
1054 break;
1055 left -= buf->len;
1056 i_head++;
1057 }
1058 i->head = i_head;
1059 i->iov_offset = buf->offset + left;
1060 }
1061 i->count -= size;
1062 /* ... and discard everything past that point */
1063 pipe_truncate(i);
1064}
1065
1066void iov_iter_advance(struct iov_iter *i, size_t size)
1067{
1068 if (unlikely(iov_iter_is_pipe(i))) {
1069 pipe_advance(i, size);
1070 return;
1071 }
1072 if (unlikely(iov_iter_is_discard(i))) {
1073 i->count -= size;
1074 return;
1075 }
1076 iterate_and_advance(i, size, v, 0, 0, 0)
1077}
1078EXPORT_SYMBOL(iov_iter_advance);
1079
1080void iov_iter_revert(struct iov_iter *i, size_t unroll)
1081{
1082 if (!unroll)
1083 return;
1084 if (WARN_ON(unroll > MAX_RW_COUNT))
1085 return;
1086 i->count += unroll;
1087 if (unlikely(iov_iter_is_pipe(i))) {
1088 struct pipe_inode_info *pipe = i->pipe;
1089 unsigned int p_mask = pipe->ring_size - 1;
1090 unsigned int i_head = i->head;
1091 size_t off = i->iov_offset;
1092 while (1) {
1093 struct pipe_buffer *b = &pipe->bufs[i_head & p_mask];
1094 size_t n = off - b->offset;
1095 if (unroll < n) {
1096 off -= unroll;
1097 break;
1098 }
1099 unroll -= n;
1100 if (!unroll && i_head == i->start_head) {
1101 off = 0;
1102 break;
1103 }
1104 i_head--;
1105 b = &pipe->bufs[i_head & p_mask];
1106 off = b->offset + b->len;
1107 }
1108 i->iov_offset = off;
1109 i->head = i_head;
1110 pipe_truncate(i);
1111 return;
1112 }
1113 if (unlikely(iov_iter_is_discard(i)))
1114 return;
1115 if (unroll <= i->iov_offset) {
1116 i->iov_offset -= unroll;
1117 return;
1118 }
1119 unroll -= i->iov_offset;
1120 if (iov_iter_is_bvec(i)) {
1121 const struct bio_vec *bvec = i->bvec;
1122 while (1) {
1123 size_t n = (--bvec)->bv_len;
1124 i->nr_segs++;
1125 if (unroll <= n) {
1126 i->bvec = bvec;
1127 i->iov_offset = n - unroll;
1128 return;
1129 }
1130 unroll -= n;
1131 }
1132 } else { /* same logics for iovec and kvec */
1133 const struct iovec *iov = i->iov;
1134 while (1) {
1135 size_t n = (--iov)->iov_len;
1136 i->nr_segs++;
1137 if (unroll <= n) {
1138 i->iov = iov;
1139 i->iov_offset = n - unroll;
1140 return;
1141 }
1142 unroll -= n;
1143 }
1144 }
1145}
1146EXPORT_SYMBOL(iov_iter_revert);
1147
1148/*
1149 * Return the count of just the current iov_iter segment.
1150 */
1151size_t iov_iter_single_seg_count(const struct iov_iter *i)
1152{
1153 if (unlikely(iov_iter_is_pipe(i)))
1154 return i->count; // it is a silly place, anyway
1155 if (i->nr_segs == 1)
1156 return i->count;
1157 if (unlikely(iov_iter_is_discard(i)))
1158 return i->count;
1159 else if (iov_iter_is_bvec(i))
1160 return min(i->count, i->bvec->bv_len - i->iov_offset);
1161 else
1162 return min(i->count, i->iov->iov_len - i->iov_offset);
1163}
1164EXPORT_SYMBOL(iov_iter_single_seg_count);
1165
1166void iov_iter_kvec(struct iov_iter *i, unsigned int direction,
1167 const struct kvec *kvec, unsigned long nr_segs,
1168 size_t count)
1169{
1170 WARN_ON(direction & ~(READ | WRITE));
1171 i->type = ITER_KVEC | (direction & (READ | WRITE));
1172 i->kvec = kvec;
1173 i->nr_segs = nr_segs;
1174 i->iov_offset = 0;
1175 i->count = count;
1176}
1177EXPORT_SYMBOL(iov_iter_kvec);
1178
1179void iov_iter_bvec(struct iov_iter *i, unsigned int direction,
1180 const struct bio_vec *bvec, unsigned long nr_segs,
1181 size_t count)
1182{
1183 WARN_ON(direction & ~(READ | WRITE));
1184 i->type = ITER_BVEC | (direction & (READ | WRITE));
1185 i->bvec = bvec;
1186 i->nr_segs = nr_segs;
1187 i->iov_offset = 0;
1188 i->count = count;
1189}
1190EXPORT_SYMBOL(iov_iter_bvec);
1191
1192void iov_iter_pipe(struct iov_iter *i, unsigned int direction,
1193 struct pipe_inode_info *pipe,
1194 size_t count)
1195{
1196 BUG_ON(direction != READ);
1197 WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size));
1198 i->type = ITER_PIPE | READ;
1199 i->pipe = pipe;
1200 i->head = pipe->head;
1201 i->iov_offset = 0;
1202 i->count = count;
1203 i->start_head = i->head;
1204}
1205EXPORT_SYMBOL(iov_iter_pipe);
1206
1207/**
1208 * iov_iter_discard - Initialise an I/O iterator that discards data
1209 * @i: The iterator to initialise.
1210 * @direction: The direction of the transfer.
1211 * @count: The size of the I/O buffer in bytes.
1212 *
1213 * Set up an I/O iterator that just discards everything that's written to it.
1214 * It's only available as a READ iterator.
1215 */
1216void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count)
1217{
1218 BUG_ON(direction != READ);
1219 i->type = ITER_DISCARD | READ;
1220 i->count = count;
1221 i->iov_offset = 0;
1222}
1223EXPORT_SYMBOL(iov_iter_discard);
1224
1225unsigned long iov_iter_alignment(const struct iov_iter *i)
1226{
1227 unsigned long res = 0;
1228 size_t size = i->count;
1229
1230 if (unlikely(iov_iter_is_pipe(i))) {
1231 unsigned int p_mask = i->pipe->ring_size - 1;
1232
1233 if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask]))
1234 return size | i->iov_offset;
1235 return size;
1236 }
1237 iterate_all_kinds(i, size, v,
1238 (res |= (unsigned long)v.iov_base | v.iov_len, 0),
1239 res |= v.bv_offset | v.bv_len,
1240 res |= (unsigned long)v.iov_base | v.iov_len
1241 )
1242 return res;
1243}
1244EXPORT_SYMBOL(iov_iter_alignment);
1245
1246unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
1247{
1248 unsigned long res = 0;
1249 size_t size = i->count;
1250
1251 if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
1252 WARN_ON(1);
1253 return ~0U;
1254 }
1255
1256 iterate_all_kinds(i, size, v,
1257 (res |= (!res ? 0 : (unsigned long)v.iov_base) |
1258 (size != v.iov_len ? size : 0), 0),
1259 (res |= (!res ? 0 : (unsigned long)v.bv_offset) |
1260 (size != v.bv_len ? size : 0)),
1261 (res |= (!res ? 0 : (unsigned long)v.iov_base) |
1262 (size != v.iov_len ? size : 0))
1263 );
1264 return res;
1265}
1266EXPORT_SYMBOL(iov_iter_gap_alignment);
1267
1268static inline ssize_t __pipe_get_pages(struct iov_iter *i,
1269 size_t maxsize,
1270 struct page **pages,
1271 int iter_head,
1272 size_t *start)
1273{
1274 struct pipe_inode_info *pipe = i->pipe;
1275 unsigned int p_mask = pipe->ring_size - 1;
1276 ssize_t n = push_pipe(i, maxsize, &iter_head, start);
1277 if (!n)
1278 return -EFAULT;
1279
1280 maxsize = n;
1281 n += *start;
1282 while (n > 0) {
1283 get_page(*pages++ = pipe->bufs[iter_head & p_mask].page);
1284 iter_head++;
1285 n -= PAGE_SIZE;
1286 }
1287
1288 return maxsize;
1289}
1290
1291static ssize_t pipe_get_pages(struct iov_iter *i,
1292 struct page **pages, size_t maxsize, unsigned maxpages,
1293 size_t *start)
1294{
1295 unsigned int iter_head, npages;
1296 size_t capacity;
1297
1298 if (!maxsize)
1299 return 0;
1300
1301 if (!sanity(i))
1302 return -EFAULT;
1303
1304 data_start(i, &iter_head, start);
1305 /* Amount of free space: some of this one + all after this one */
1306 npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe);
1307 capacity = min(npages, maxpages) * PAGE_SIZE - *start;
1308
1309 return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start);
1310}
1311
1312ssize_t iov_iter_get_pages(struct iov_iter *i,
1313 struct page **pages, size_t maxsize, unsigned maxpages,
1314 size_t *start)
1315{
1316 if (maxsize > i->count)
1317 maxsize = i->count;
1318
1319 if (unlikely(iov_iter_is_pipe(i)))
1320 return pipe_get_pages(i, pages, maxsize, maxpages, start);
1321 if (unlikely(iov_iter_is_discard(i)))
1322 return -EFAULT;
1323
1324 iterate_all_kinds(i, maxsize, v, ({
1325 unsigned long addr = (unsigned long)v.iov_base;
1326 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
1327 int n;
1328 int res;
1329
1330 if (len > maxpages * PAGE_SIZE)
1331 len = maxpages * PAGE_SIZE;
1332 addr &= ~(PAGE_SIZE - 1);
1333 n = DIV_ROUND_UP(len, PAGE_SIZE);
1334 res = get_user_pages_fast(addr, n,
1335 iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0,
1336 pages);
1337 if (unlikely(res < 0))
1338 return res;
1339 return (res == n ? len : res * PAGE_SIZE) - *start;
1340 0;}),({
1341 /* can't be more than PAGE_SIZE */
1342 *start = v.bv_offset;
1343 get_page(*pages = v.bv_page);
1344 return v.bv_len;
1345 }),({
1346 return -EFAULT;
1347 })
1348 )
1349 return 0;
1350}
1351EXPORT_SYMBOL(iov_iter_get_pages);
1352
1353static struct page **get_pages_array(size_t n)
1354{
1355 return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL);
1356}
1357
1358static ssize_t pipe_get_pages_alloc(struct iov_iter *i,
1359 struct page ***pages, size_t maxsize,
1360 size_t *start)
1361{
1362 struct page **p;
1363 unsigned int iter_head, npages;
1364 ssize_t n;
1365
1366 if (!maxsize)
1367 return 0;
1368
1369 if (!sanity(i))
1370 return -EFAULT;
1371
1372 data_start(i, &iter_head, start);
1373 /* Amount of free space: some of this one + all after this one */
1374 npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe);
1375 n = npages * PAGE_SIZE - *start;
1376 if (maxsize > n)
1377 maxsize = n;
1378 else
1379 npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
1380 p = get_pages_array(npages);
1381 if (!p)
1382 return -ENOMEM;
1383 n = __pipe_get_pages(i, maxsize, p, iter_head, start);
1384 if (n > 0)
1385 *pages = p;
1386 else
1387 kvfree(p);
1388 return n;
1389}
1390
1391ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
1392 struct page ***pages, size_t maxsize,
1393 size_t *start)
1394{
1395 struct page **p;
1396
1397 if (maxsize > i->count)
1398 maxsize = i->count;
1399
1400 if (unlikely(iov_iter_is_pipe(i)))
1401 return pipe_get_pages_alloc(i, pages, maxsize, start);
1402 if (unlikely(iov_iter_is_discard(i)))
1403 return -EFAULT;
1404
1405 iterate_all_kinds(i, maxsize, v, ({
1406 unsigned long addr = (unsigned long)v.iov_base;
1407 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
1408 int n;
1409 int res;
1410
1411 addr &= ~(PAGE_SIZE - 1);
1412 n = DIV_ROUND_UP(len, PAGE_SIZE);
1413 p = get_pages_array(n);
1414 if (!p)
1415 return -ENOMEM;
1416 res = get_user_pages_fast(addr, n,
1417 iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p);
1418 if (unlikely(res < 0)) {
1419 kvfree(p);
1420 return res;
1421 }
1422 *pages = p;
1423 return (res == n ? len : res * PAGE_SIZE) - *start;
1424 0;}),({
1425 /* can't be more than PAGE_SIZE */
1426 *start = v.bv_offset;
1427 *pages = p = get_pages_array(1);
1428 if (!p)
1429 return -ENOMEM;
1430 get_page(*p = v.bv_page);
1431 return v.bv_len;
1432 }),({
1433 return -EFAULT;
1434 })
1435 )
1436 return 0;
1437}
1438EXPORT_SYMBOL(iov_iter_get_pages_alloc);
1439
1440size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
1441 struct iov_iter *i)
1442{
1443 char *to = addr;
1444 __wsum sum, next;
1445 size_t off = 0;
1446 sum = *csum;
1447 if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
1448 WARN_ON(1);
1449 return 0;
1450 }
1451 iterate_and_advance(i, bytes, v, ({
1452 int err = 0;
1453 next = csum_and_copy_from_user(v.iov_base,
1454 (to += v.iov_len) - v.iov_len,
1455 v.iov_len, 0, &err);
1456 if (!err) {
1457 sum = csum_block_add(sum, next, off);
1458 off += v.iov_len;
1459 }
1460 err ? v.iov_len : 0;
1461 }), ({
1462 char *p = kmap_atomic(v.bv_page);
1463 sum = csum_and_memcpy((to += v.bv_len) - v.bv_len,
1464 p + v.bv_offset, v.bv_len,
1465 sum, off);
1466 kunmap_atomic(p);
1467 off += v.bv_len;
1468 }),({
1469 sum = csum_and_memcpy((to += v.iov_len) - v.iov_len,
1470 v.iov_base, v.iov_len,
1471 sum, off);
1472 off += v.iov_len;
1473 })
1474 )
1475 *csum = sum;
1476 return bytes;
1477}
1478EXPORT_SYMBOL(csum_and_copy_from_iter);
1479
1480bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
1481 struct iov_iter *i)
1482{
1483 char *to = addr;
1484 __wsum sum, next;
1485 size_t off = 0;
1486 sum = *csum;
1487 if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
1488 WARN_ON(1);
1489 return false;
1490 }
1491 if (unlikely(i->count < bytes))
1492 return false;
1493 iterate_all_kinds(i, bytes, v, ({
1494 int err = 0;
1495 next = csum_and_copy_from_user(v.iov_base,
1496 (to += v.iov_len) - v.iov_len,
1497 v.iov_len, 0, &err);
1498 if (err)
1499 return false;
1500 sum = csum_block_add(sum, next, off);
1501 off += v.iov_len;
1502 0;
1503 }), ({
1504 char *p = kmap_atomic(v.bv_page);
1505 sum = csum_and_memcpy((to += v.bv_len) - v.bv_len,
1506 p + v.bv_offset, v.bv_len,
1507 sum, off);
1508 kunmap_atomic(p);
1509 off += v.bv_len;
1510 }),({
1511 sum = csum_and_memcpy((to += v.iov_len) - v.iov_len,
1512 v.iov_base, v.iov_len,
1513 sum, off);
1514 off += v.iov_len;
1515 })
1516 )
1517 *csum = sum;
1518 iov_iter_advance(i, bytes);
1519 return true;
1520}
1521EXPORT_SYMBOL(csum_and_copy_from_iter_full);
1522
1523size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump,
1524 struct iov_iter *i)
1525{
1526 const char *from = addr;
1527 __wsum *csum = csump;
1528 __wsum sum, next;
1529 size_t off = 0;
1530
1531 if (unlikely(iov_iter_is_pipe(i)))
1532 return csum_and_copy_to_pipe_iter(addr, bytes, csum, i);
1533
1534 sum = *csum;
1535 if (unlikely(iov_iter_is_discard(i))) {
1536 WARN_ON(1); /* for now */
1537 return 0;
1538 }
1539 iterate_and_advance(i, bytes, v, ({
1540 int err = 0;
1541 next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
1542 v.iov_base,
1543 v.iov_len, 0, &err);
1544 if (!err) {
1545 sum = csum_block_add(sum, next, off);
1546 off += v.iov_len;
1547 }
1548 err ? v.iov_len : 0;
1549 }), ({
1550 char *p = kmap_atomic(v.bv_page);
1551 sum = csum_and_memcpy(p + v.bv_offset,
1552 (from += v.bv_len) - v.bv_len,
1553 v.bv_len, sum, off);
1554 kunmap_atomic(p);
1555 off += v.bv_len;
1556 }),({
1557 sum = csum_and_memcpy(v.iov_base,
1558 (from += v.iov_len) - v.iov_len,
1559 v.iov_len, sum, off);
1560 off += v.iov_len;
1561 })
1562 )
1563 *csum = sum;
1564 return bytes;
1565}
1566EXPORT_SYMBOL(csum_and_copy_to_iter);
1567
1568size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
1569 struct iov_iter *i)
1570{
1571#ifdef CONFIG_CRYPTO_HASH
1572 struct ahash_request *hash = hashp;
1573 struct scatterlist sg;
1574 size_t copied;
1575
1576 copied = copy_to_iter(addr, bytes, i);
1577 sg_init_one(&sg, addr, copied);
1578 ahash_request_set_crypt(hash, &sg, NULL, copied);
1579 crypto_ahash_update(hash);
1580 return copied;
1581#else
1582 return 0;
1583#endif
1584}
1585EXPORT_SYMBOL(hash_and_copy_to_iter);
1586
1587int iov_iter_npages(const struct iov_iter *i, int maxpages)
1588{
1589 size_t size = i->count;
1590 int npages = 0;
1591
1592 if (!size)
1593 return 0;
1594 if (unlikely(iov_iter_is_discard(i)))
1595 return 0;
1596
1597 if (unlikely(iov_iter_is_pipe(i))) {
1598 struct pipe_inode_info *pipe = i->pipe;
1599 unsigned int iter_head;
1600 size_t off;
1601
1602 if (!sanity(i))
1603 return 0;
1604
1605 data_start(i, &iter_head, &off);
1606 /* some of this one + all after this one */
1607 npages = pipe_space_for_user(iter_head, pipe->tail, pipe);
1608 if (npages >= maxpages)
1609 return maxpages;
1610 } else iterate_all_kinds(i, size, v, ({
1611 unsigned long p = (unsigned long)v.iov_base;
1612 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
1613 - p / PAGE_SIZE;
1614 if (npages >= maxpages)
1615 return maxpages;
1616 0;}),({
1617 npages++;
1618 if (npages >= maxpages)
1619 return maxpages;
1620 }),({
1621 unsigned long p = (unsigned long)v.iov_base;
1622 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
1623 - p / PAGE_SIZE;
1624 if (npages >= maxpages)
1625 return maxpages;
1626 })
1627 )
1628 return npages;
1629}
1630EXPORT_SYMBOL(iov_iter_npages);
1631
1632const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
1633{
1634 *new = *old;
1635 if (unlikely(iov_iter_is_pipe(new))) {
1636 WARN_ON(1);
1637 return NULL;
1638 }
1639 if (unlikely(iov_iter_is_discard(new)))
1640 return NULL;
1641 if (iov_iter_is_bvec(new))
1642 return new->bvec = kmemdup(new->bvec,
1643 new->nr_segs * sizeof(struct bio_vec),
1644 flags);
1645 else
1646 /* iovec and kvec have identical layout */
1647 return new->iov = kmemdup(new->iov,
1648 new->nr_segs * sizeof(struct iovec),
1649 flags);
1650}
1651EXPORT_SYMBOL(dup_iter);
1652
1653/**
1654 * import_iovec() - Copy an array of &struct iovec from userspace
1655 * into the kernel, check that it is valid, and initialize a new
1656 * &struct iov_iter iterator to access it.
1657 *
1658 * @type: One of %READ or %WRITE.
1659 * @uvector: Pointer to the userspace array.
1660 * @nr_segs: Number of elements in userspace array.
1661 * @fast_segs: Number of elements in @iov.
1662 * @iov: (input and output parameter) Pointer to pointer to (usually small
1663 * on-stack) kernel array.
1664 * @i: Pointer to iterator that will be initialized on success.
1665 *
1666 * If the array pointed to by *@iov is large enough to hold all @nr_segs,
1667 * then this function places %NULL in *@iov on return. Otherwise, a new
1668 * array will be allocated and the result placed in *@iov. This means that
1669 * the caller may call kfree() on *@iov regardless of whether the small
1670 * on-stack array was used or not (and regardless of whether this function
1671 * returns an error or not).
1672 *
1673 * Return: Negative error code on error, bytes imported on success
1674 */
1675ssize_t import_iovec(int type, const struct iovec __user * uvector,
1676 unsigned nr_segs, unsigned fast_segs,
1677 struct iovec **iov, struct iov_iter *i)
1678{
1679 ssize_t n;
1680 struct iovec *p;
1681 n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
1682 *iov, &p);
1683 if (n < 0) {
1684 if (p != *iov)
1685 kfree(p);
1686 *iov = NULL;
1687 return n;
1688 }
1689 iov_iter_init(i, type, p, nr_segs, n);
1690 *iov = p == *iov ? NULL : p;
1691 return n;
1692}
1693EXPORT_SYMBOL(import_iovec);
1694
1695#ifdef CONFIG_COMPAT
1696#include <linux/compat.h>
1697
1698ssize_t compat_import_iovec(int type,
1699 const struct compat_iovec __user * uvector,
1700 unsigned nr_segs, unsigned fast_segs,
1701 struct iovec **iov, struct iov_iter *i)
1702{
1703 ssize_t n;
1704 struct iovec *p;
1705 n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
1706 *iov, &p);
1707 if (n < 0) {
1708 if (p != *iov)
1709 kfree(p);
1710 *iov = NULL;
1711 return n;
1712 }
1713 iov_iter_init(i, type, p, nr_segs, n);
1714 *iov = p == *iov ? NULL : p;
1715 return n;
1716}
1717EXPORT_SYMBOL(compat_import_iovec);
1718#endif
1719
1720int import_single_range(int rw, void __user *buf, size_t len,
1721 struct iovec *iov, struct iov_iter *i)
1722{
1723 if (len > MAX_RW_COUNT)
1724 len = MAX_RW_COUNT;
1725 if (unlikely(!access_ok(buf, len)))
1726 return -EFAULT;
1727
1728 iov->iov_base = buf;
1729 iov->iov_len = len;
1730 iov_iter_init(i, rw, iov, 1, len);
1731 return 0;
1732}
1733EXPORT_SYMBOL(import_single_range);
1734
1735int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
1736 int (*f)(struct kvec *vec, void *context),
1737 void *context)
1738{
1739 struct kvec w;
1740 int err = -EINVAL;
1741 if (!bytes)
1742 return 0;
1743
1744 iterate_all_kinds(i, bytes, v, -EINVAL, ({
1745 w.iov_base = kmap(v.bv_page) + v.bv_offset;
1746 w.iov_len = v.bv_len;
1747 err = f(&w, context);
1748 kunmap(v.bv_page);
1749 err;}), ({
1750 w = v;
1751 err = f(&w, context);})
1752 )
1753 return err;
1754}
1755EXPORT_SYMBOL(iov_iter_for_each_range);