1 #include <linux/export.h>
3 #include <linux/pagemap.h>
4 #include <linux/slab.h>
5 #include <linux/vmalloc.h>
6 #include <net/checksum.h>
8 #define iterate_iovec(i, n, __v, __p, skip, STEP) { \
12 __v.iov_len = min(n, __p->iov_len - skip); \
13 if (likely(__v.iov_len)) { \
14 __v.iov_base = __p->iov_base + skip; \
16 __v.iov_len -= left; \
17 skip += __v.iov_len; \
22 while (unlikely(!left && n)) { \
24 __v.iov_len = min(n, __p->iov_len); \
25 if (unlikely(!__v.iov_len)) \
27 __v.iov_base = __p->iov_base; \
29 __v.iov_len -= left; \
36 #define iterate_kvec(i, n, __v, __p, skip, STEP) { \
39 __v.iov_len = min(n, __p->iov_len - skip); \
40 if (likely(__v.iov_len)) { \
41 __v.iov_base = __p->iov_base + skip; \
43 skip += __v.iov_len; \
46 while (unlikely(n)) { \
48 __v.iov_len = min(n, __p->iov_len); \
49 if (unlikely(!__v.iov_len)) \
51 __v.iov_base = __p->iov_base; \
59 #define iterate_bvec(i, n, __v, __p, skip, STEP) { \
62 __v.bv_len = min_t(size_t, n, __p->bv_len - skip); \
63 if (likely(__v.bv_len)) { \
64 __v.bv_page = __p->bv_page; \
65 __v.bv_offset = __p->bv_offset + skip; \
70 while (unlikely(n)) { \
72 __v.bv_len = min_t(size_t, n, __p->bv_len); \
73 if (unlikely(!__v.bv_len)) \
75 __v.bv_page = __p->bv_page; \
76 __v.bv_offset = __p->bv_offset; \
84 #define iterate_all_kinds(i, n, v, I, B, K) { \
85 size_t skip = i->iov_offset; \
86 if (unlikely(i->type & ITER_BVEC)) { \
87 const struct bio_vec *bvec; \
89 iterate_bvec(i, n, v, bvec, skip, (B)) \
90 } else if (unlikely(i->type & ITER_KVEC)) { \
91 const struct kvec *kvec; \
93 iterate_kvec(i, n, v, kvec, skip, (K)) \
95 const struct iovec *iov; \
97 iterate_iovec(i, n, v, iov, skip, (I)) \
101 #define iterate_and_advance(i, n, v, I, B, K) { \
102 size_t skip = i->iov_offset; \
103 if (unlikely(i->type & ITER_BVEC)) { \
104 const struct bio_vec *bvec; \
106 iterate_bvec(i, n, v, bvec, skip, (B)) \
107 if (skip == bvec->bv_len) { \
111 i->nr_segs -= bvec - i->bvec; \
113 } else if (unlikely(i->type & ITER_KVEC)) { \
114 const struct kvec *kvec; \
116 iterate_kvec(i, n, v, kvec, skip, (K)) \
117 if (skip == kvec->iov_len) { \
121 i->nr_segs -= kvec - i->kvec; \
124 const struct iovec *iov; \
126 iterate_iovec(i, n, v, iov, skip, (I)) \
127 if (skip == iov->iov_len) { \
131 i->nr_segs -= iov - i->iov; \
135 i->iov_offset = skip; \
138 static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
141 size_t skip, copy, left, wanted;
142 const struct iovec *iov;
146 if (unlikely(bytes > i->count))
149 if (unlikely(!bytes))
154 skip = i->iov_offset;
155 buf = iov->iov_base + skip;
156 copy = min(bytes, iov->iov_len - skip);
158 if (!fault_in_pages_writeable(buf, copy)) {
159 kaddr = kmap_atomic(page);
160 from = kaddr + offset;
162 /* first chunk, usually the only one */
163 left = __copy_to_user_inatomic(buf, from, copy);
169 while (unlikely(!left && bytes)) {
172 copy = min(bytes, iov->iov_len);
173 left = __copy_to_user_inatomic(buf, from, copy);
179 if (likely(!bytes)) {
180 kunmap_atomic(kaddr);
183 offset = from - kaddr;
185 kunmap_atomic(kaddr);
186 copy = min(bytes, iov->iov_len - skip);
188 /* Too bad - revert to non-atomic kmap */
190 from = kaddr + offset;
191 left = __copy_to_user(buf, from, copy);
196 while (unlikely(!left && bytes)) {
199 copy = min(bytes, iov->iov_len);
200 left = __copy_to_user(buf, from, copy);
208 if (skip == iov->iov_len) {
212 i->count -= wanted - bytes;
213 i->nr_segs -= iov - i->iov;
215 i->iov_offset = skip;
216 return wanted - bytes;
219 static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
222 size_t skip, copy, left, wanted;
223 const struct iovec *iov;
227 if (unlikely(bytes > i->count))
230 if (unlikely(!bytes))
235 skip = i->iov_offset;
236 buf = iov->iov_base + skip;
237 copy = min(bytes, iov->iov_len - skip);
239 if (!fault_in_pages_readable(buf, copy)) {
240 kaddr = kmap_atomic(page);
243 /* first chunk, usually the only one */
244 left = __copy_from_user_inatomic(to, buf, copy);
250 while (unlikely(!left && bytes)) {
253 copy = min(bytes, iov->iov_len);
254 left = __copy_from_user_inatomic(to, buf, copy);
260 if (likely(!bytes)) {
261 kunmap_atomic(kaddr);
266 kunmap_atomic(kaddr);
267 copy = min(bytes, iov->iov_len - skip);
269 /* Too bad - revert to non-atomic kmap */
272 left = __copy_from_user(to, buf, copy);
277 while (unlikely(!left && bytes)) {
280 copy = min(bytes, iov->iov_len);
281 left = __copy_from_user(to, buf, copy);
289 if (skip == iov->iov_len) {
293 i->count -= wanted - bytes;
294 i->nr_segs -= iov - i->iov;
296 i->iov_offset = skip;
297 return wanted - bytes;
301 * Fault in the first iovec of the given iov_iter, to a maximum length
302 * of bytes. Returns 0 on success, or non-zero if the memory could not be
303 * accessed (ie. because it is an invalid address).
305 * writev-intensive code may want this to prefault several iovecs -- that
306 * would be possible (callers must not rely on the fact that _only_ the
307 * first iovec will be faulted with the current implementation).
309 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
311 if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
312 char __user *buf = i->iov->iov_base + i->iov_offset;
313 bytes = min(bytes, i->iov->iov_len - i->iov_offset);
314 return fault_in_pages_readable(buf, bytes);
318 EXPORT_SYMBOL(iov_iter_fault_in_readable);
320 void iov_iter_init(struct iov_iter *i, int direction,
321 const struct iovec *iov, unsigned long nr_segs,
324 /* It will get better. Eventually... */
325 if (segment_eq(get_fs(), KERNEL_DS)) {
326 direction |= ITER_KVEC;
328 i->kvec = (struct kvec *)iov;
333 i->nr_segs = nr_segs;
337 EXPORT_SYMBOL(iov_iter_init);
339 static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
341 char *from = kmap_atomic(page);
342 memcpy(to, from + offset, len);
346 static void memcpy_to_page(struct page *page, size_t offset, char *from, size_t len)
348 char *to = kmap_atomic(page);
349 memcpy(to + offset, from, len);
353 static void memzero_page(struct page *page, size_t offset, size_t len)
355 char *addr = kmap_atomic(page);
356 memset(addr + offset, 0, len);
360 size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)
363 if (unlikely(bytes > i->count))
366 if (unlikely(!bytes))
369 iterate_and_advance(i, bytes, v,
370 __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
372 memcpy_to_page(v.bv_page, v.bv_offset,
373 (from += v.bv_len) - v.bv_len, v.bv_len),
374 memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)
379 EXPORT_SYMBOL(copy_to_iter);
381 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
384 if (unlikely(bytes > i->count))
387 if (unlikely(!bytes))
390 iterate_and_advance(i, bytes, v,
391 __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
393 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
394 v.bv_offset, v.bv_len),
395 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
400 EXPORT_SYMBOL(copy_from_iter);
402 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
405 if (unlikely(bytes > i->count))
408 if (unlikely(!bytes))
411 iterate_and_advance(i, bytes, v,
412 __copy_from_user_nocache((to += v.iov_len) - v.iov_len,
413 v.iov_base, v.iov_len),
414 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
415 v.bv_offset, v.bv_len),
416 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
421 EXPORT_SYMBOL(copy_from_iter_nocache);
423 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
426 if (i->type & (ITER_BVEC|ITER_KVEC)) {
427 void *kaddr = kmap_atomic(page);
428 size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
429 kunmap_atomic(kaddr);
432 return copy_page_to_iter_iovec(page, offset, bytes, i);
434 EXPORT_SYMBOL(copy_page_to_iter);
436 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
439 if (i->type & (ITER_BVEC|ITER_KVEC)) {
440 void *kaddr = kmap_atomic(page);
441 size_t wanted = copy_from_iter(kaddr + offset, bytes, i);
442 kunmap_atomic(kaddr);
445 return copy_page_from_iter_iovec(page, offset, bytes, i);
447 EXPORT_SYMBOL(copy_page_from_iter);
449 size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
451 if (unlikely(bytes > i->count))
454 if (unlikely(!bytes))
457 iterate_and_advance(i, bytes, v,
458 __clear_user(v.iov_base, v.iov_len),
459 memzero_page(v.bv_page, v.bv_offset, v.bv_len),
460 memset(v.iov_base, 0, v.iov_len)
465 EXPORT_SYMBOL(iov_iter_zero);
467 size_t iov_iter_copy_from_user_atomic(struct page *page,
468 struct iov_iter *i, unsigned long offset, size_t bytes)
470 char *kaddr = kmap_atomic(page), *p = kaddr + offset;
471 iterate_all_kinds(i, bytes, v,
472 __copy_from_user_inatomic((p += v.iov_len) - v.iov_len,
473 v.iov_base, v.iov_len),
474 memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
475 v.bv_offset, v.bv_len),
476 memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
478 kunmap_atomic(kaddr);
481 EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
483 void iov_iter_advance(struct iov_iter *i, size_t size)
485 iterate_and_advance(i, size, v, 0, 0, 0)
487 EXPORT_SYMBOL(iov_iter_advance);
490 * Return the count of just the current iov_iter segment.
492 size_t iov_iter_single_seg_count(const struct iov_iter *i)
496 else if (i->type & ITER_BVEC)
497 return min(i->count, i->bvec->bv_len - i->iov_offset);
499 return min(i->count, i->iov->iov_len - i->iov_offset);
501 EXPORT_SYMBOL(iov_iter_single_seg_count);
503 void iov_iter_kvec(struct iov_iter *i, int direction,
504 const struct kvec *kvec, unsigned long nr_segs,
507 BUG_ON(!(direction & ITER_KVEC));
510 i->nr_segs = nr_segs;
514 EXPORT_SYMBOL(iov_iter_kvec);
516 void iov_iter_bvec(struct iov_iter *i, int direction,
517 const struct bio_vec *bvec, unsigned long nr_segs,
520 BUG_ON(!(direction & ITER_BVEC));
523 i->nr_segs = nr_segs;
527 EXPORT_SYMBOL(iov_iter_bvec);
529 unsigned long iov_iter_alignment(const struct iov_iter *i)
531 unsigned long res = 0;
532 size_t size = i->count;
537 iterate_all_kinds(i, size, v,
538 (res |= (unsigned long)v.iov_base | v.iov_len, 0),
539 res |= v.bv_offset | v.bv_len,
540 res |= (unsigned long)v.iov_base | v.iov_len
544 EXPORT_SYMBOL(iov_iter_alignment);
546 ssize_t iov_iter_get_pages(struct iov_iter *i,
547 struct page **pages, size_t maxsize, unsigned maxpages,
550 if (maxsize > i->count)
556 iterate_all_kinds(i, maxsize, v, ({
557 unsigned long addr = (unsigned long)v.iov_base;
558 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
562 if (len > maxpages * PAGE_SIZE)
563 len = maxpages * PAGE_SIZE;
564 addr &= ~(PAGE_SIZE - 1);
565 n = DIV_ROUND_UP(len, PAGE_SIZE);
566 res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
567 if (unlikely(res < 0))
569 return (res == n ? len : res * PAGE_SIZE) - *start;
571 /* can't be more than PAGE_SIZE */
572 *start = v.bv_offset;
573 get_page(*pages = v.bv_page);
581 EXPORT_SYMBOL(iov_iter_get_pages);
583 static struct page **get_pages_array(size_t n)
585 struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
587 p = vmalloc(n * sizeof(struct page *));
591 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
592 struct page ***pages, size_t maxsize,
597 if (maxsize > i->count)
603 iterate_all_kinds(i, maxsize, v, ({
604 unsigned long addr = (unsigned long)v.iov_base;
605 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
609 addr &= ~(PAGE_SIZE - 1);
610 n = DIV_ROUND_UP(len, PAGE_SIZE);
611 p = get_pages_array(n);
614 res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
615 if (unlikely(res < 0)) {
620 return (res == n ? len : res * PAGE_SIZE) - *start;
622 /* can't be more than PAGE_SIZE */
623 *start = v.bv_offset;
624 *pages = p = get_pages_array(1);
627 get_page(*p = v.bv_page);
635 EXPORT_SYMBOL(iov_iter_get_pages_alloc);
637 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
643 if (unlikely(bytes > i->count))
646 if (unlikely(!bytes))
650 iterate_and_advance(i, bytes, v, ({
652 next = csum_and_copy_from_user(v.iov_base,
653 (to += v.iov_len) - v.iov_len,
656 sum = csum_block_add(sum, next, off);
661 char *p = kmap_atomic(v.bv_page);
662 next = csum_partial_copy_nocheck(p + v.bv_offset,
663 (to += v.bv_len) - v.bv_len,
666 sum = csum_block_add(sum, next, off);
669 next = csum_partial_copy_nocheck(v.iov_base,
670 (to += v.iov_len) - v.iov_len,
672 sum = csum_block_add(sum, next, off);
679 EXPORT_SYMBOL(csum_and_copy_from_iter);
681 size_t csum_and_copy_to_iter(void *addr, size_t bytes, __wsum *csum,
687 if (unlikely(bytes > i->count))
690 if (unlikely(!bytes))
694 iterate_and_advance(i, bytes, v, ({
696 next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
700 sum = csum_block_add(sum, next, off);
705 char *p = kmap_atomic(v.bv_page);
706 next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len,
710 sum = csum_block_add(sum, next, off);
713 next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len,
716 sum = csum_block_add(sum, next, off);
723 EXPORT_SYMBOL(csum_and_copy_to_iter);
725 int iov_iter_npages(const struct iov_iter *i, int maxpages)
727 size_t size = i->count;
733 iterate_all_kinds(i, size, v, ({
734 unsigned long p = (unsigned long)v.iov_base;
735 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
737 if (npages >= maxpages)
741 if (npages >= maxpages)
744 unsigned long p = (unsigned long)v.iov_base;
745 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
747 if (npages >= maxpages)
753 EXPORT_SYMBOL(iov_iter_npages);
755 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
758 if (new->type & ITER_BVEC)
759 return new->bvec = kmemdup(new->bvec,
760 new->nr_segs * sizeof(struct bio_vec),
763 /* iovec and kvec have identical layout */
764 return new->iov = kmemdup(new->iov,
765 new->nr_segs * sizeof(struct iovec),
768 EXPORT_SYMBOL(dup_iter);