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);
321 * Fault in one or more iovecs of the given iov_iter, to a maximum length of
322 * bytes. For each iovec, fault in each page that constitutes the iovec.
324 * Return 0 on success, or non-zero if the memory could not be accessed (i.e.
325 * because it is an invalid address).
327 int iov_iter_fault_in_multipages_readable(struct iov_iter *i, size_t bytes)
329 size_t skip = i->iov_offset;
330 const struct iovec *iov;
334 if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
335 iterate_iovec(i, bytes, v, iov, skip, ({
336 err = fault_in_multipages_readable(v.iov_base,
344 EXPORT_SYMBOL(iov_iter_fault_in_multipages_readable);
346 void iov_iter_init(struct iov_iter *i, int direction,
347 const struct iovec *iov, unsigned long nr_segs,
350 /* It will get better. Eventually... */
351 if (segment_eq(get_fs(), KERNEL_DS)) {
352 direction |= ITER_KVEC;
354 i->kvec = (struct kvec *)iov;
359 i->nr_segs = nr_segs;
363 EXPORT_SYMBOL(iov_iter_init);
365 static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
367 char *from = kmap_atomic(page);
368 memcpy(to, from + offset, len);
372 static void memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len)
374 char *to = kmap_atomic(page);
375 memcpy(to + offset, from, len);
379 static void memzero_page(struct page *page, size_t offset, size_t len)
381 char *addr = kmap_atomic(page);
382 memset(addr + offset, 0, len);
386 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
388 const char *from = addr;
389 if (unlikely(bytes > i->count))
392 if (unlikely(!bytes))
395 iterate_and_advance(i, bytes, v,
396 __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
398 memcpy_to_page(v.bv_page, v.bv_offset,
399 (from += v.bv_len) - v.bv_len, v.bv_len),
400 memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)
405 EXPORT_SYMBOL(copy_to_iter);
407 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
410 if (unlikely(bytes > i->count))
413 if (unlikely(!bytes))
416 iterate_and_advance(i, bytes, v,
417 __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
419 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
420 v.bv_offset, v.bv_len),
421 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
426 EXPORT_SYMBOL(copy_from_iter);
428 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
431 if (unlikely(bytes > i->count))
434 if (unlikely(!bytes))
437 iterate_and_advance(i, bytes, v,
438 __copy_from_user_nocache((to += v.iov_len) - v.iov_len,
439 v.iov_base, v.iov_len),
440 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
441 v.bv_offset, v.bv_len),
442 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
447 EXPORT_SYMBOL(copy_from_iter_nocache);
449 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
452 if (i->type & (ITER_BVEC|ITER_KVEC)) {
453 void *kaddr = kmap_atomic(page);
454 size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
455 kunmap_atomic(kaddr);
458 return copy_page_to_iter_iovec(page, offset, bytes, i);
460 EXPORT_SYMBOL(copy_page_to_iter);
462 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
465 if (i->type & (ITER_BVEC|ITER_KVEC)) {
466 void *kaddr = kmap_atomic(page);
467 size_t wanted = copy_from_iter(kaddr + offset, bytes, i);
468 kunmap_atomic(kaddr);
471 return copy_page_from_iter_iovec(page, offset, bytes, i);
473 EXPORT_SYMBOL(copy_page_from_iter);
475 size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
477 if (unlikely(bytes > i->count))
480 if (unlikely(!bytes))
483 iterate_and_advance(i, bytes, v,
484 __clear_user(v.iov_base, v.iov_len),
485 memzero_page(v.bv_page, v.bv_offset, v.bv_len),
486 memset(v.iov_base, 0, v.iov_len)
491 EXPORT_SYMBOL(iov_iter_zero);
493 size_t iov_iter_copy_from_user_atomic(struct page *page,
494 struct iov_iter *i, unsigned long offset, size_t bytes)
496 char *kaddr = kmap_atomic(page), *p = kaddr + offset;
497 iterate_all_kinds(i, bytes, v,
498 __copy_from_user_inatomic((p += v.iov_len) - v.iov_len,
499 v.iov_base, v.iov_len),
500 memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
501 v.bv_offset, v.bv_len),
502 memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
504 kunmap_atomic(kaddr);
507 EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
509 void iov_iter_advance(struct iov_iter *i, size_t size)
511 iterate_and_advance(i, size, v, 0, 0, 0)
513 EXPORT_SYMBOL(iov_iter_advance);
516 * Return the count of just the current iov_iter segment.
518 size_t iov_iter_single_seg_count(const struct iov_iter *i)
522 else if (i->type & ITER_BVEC)
523 return min(i->count, i->bvec->bv_len - i->iov_offset);
525 return min(i->count, i->iov->iov_len - i->iov_offset);
527 EXPORT_SYMBOL(iov_iter_single_seg_count);
529 void iov_iter_kvec(struct iov_iter *i, int direction,
530 const struct kvec *kvec, unsigned long nr_segs,
533 BUG_ON(!(direction & ITER_KVEC));
536 i->nr_segs = nr_segs;
540 EXPORT_SYMBOL(iov_iter_kvec);
542 void iov_iter_bvec(struct iov_iter *i, int direction,
543 const struct bio_vec *bvec, unsigned long nr_segs,
546 BUG_ON(!(direction & ITER_BVEC));
549 i->nr_segs = nr_segs;
553 EXPORT_SYMBOL(iov_iter_bvec);
555 unsigned long iov_iter_alignment(const struct iov_iter *i)
557 unsigned long res = 0;
558 size_t size = i->count;
563 iterate_all_kinds(i, size, v,
564 (res |= (unsigned long)v.iov_base | v.iov_len, 0),
565 res |= v.bv_offset | v.bv_len,
566 res |= (unsigned long)v.iov_base | v.iov_len
570 EXPORT_SYMBOL(iov_iter_alignment);
572 unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
574 unsigned long res = 0;
575 size_t size = i->count;
579 iterate_all_kinds(i, size, v,
580 (res |= (!res ? 0 : (unsigned long)v.iov_base) |
581 (size != v.iov_len ? size : 0), 0),
582 (res |= (!res ? 0 : (unsigned long)v.bv_offset) |
583 (size != v.bv_len ? size : 0)),
584 (res |= (!res ? 0 : (unsigned long)v.iov_base) |
585 (size != v.iov_len ? size : 0))
589 EXPORT_SYMBOL(iov_iter_gap_alignment);
591 ssize_t iov_iter_get_pages(struct iov_iter *i,
592 struct page **pages, size_t maxsize, unsigned maxpages,
595 if (maxsize > i->count)
601 iterate_all_kinds(i, maxsize, v, ({
602 unsigned long addr = (unsigned long)v.iov_base;
603 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
607 if (len > maxpages * PAGE_SIZE)
608 len = maxpages * PAGE_SIZE;
609 addr &= ~(PAGE_SIZE - 1);
610 n = DIV_ROUND_UP(len, PAGE_SIZE);
611 res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
612 if (unlikely(res < 0))
614 return (res == n ? len : res * PAGE_SIZE) - *start;
616 /* can't be more than PAGE_SIZE */
617 *start = v.bv_offset;
618 get_page(*pages = v.bv_page);
626 EXPORT_SYMBOL(iov_iter_get_pages);
628 static struct page **get_pages_array(size_t n)
630 struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
632 p = vmalloc(n * sizeof(struct page *));
636 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
637 struct page ***pages, size_t maxsize,
642 if (maxsize > i->count)
648 iterate_all_kinds(i, maxsize, v, ({
649 unsigned long addr = (unsigned long)v.iov_base;
650 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
654 addr &= ~(PAGE_SIZE - 1);
655 n = DIV_ROUND_UP(len, PAGE_SIZE);
656 p = get_pages_array(n);
659 res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
660 if (unlikely(res < 0)) {
665 return (res == n ? len : res * PAGE_SIZE) - *start;
667 /* can't be more than PAGE_SIZE */
668 *start = v.bv_offset;
669 *pages = p = get_pages_array(1);
672 get_page(*p = v.bv_page);
680 EXPORT_SYMBOL(iov_iter_get_pages_alloc);
682 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
688 if (unlikely(bytes > i->count))
691 if (unlikely(!bytes))
695 iterate_and_advance(i, bytes, v, ({
697 next = csum_and_copy_from_user(v.iov_base,
698 (to += v.iov_len) - v.iov_len,
701 sum = csum_block_add(sum, next, off);
706 char *p = kmap_atomic(v.bv_page);
707 next = csum_partial_copy_nocheck(p + v.bv_offset,
708 (to += v.bv_len) - v.bv_len,
711 sum = csum_block_add(sum, next, off);
714 next = csum_partial_copy_nocheck(v.iov_base,
715 (to += v.iov_len) - v.iov_len,
717 sum = csum_block_add(sum, next, off);
724 EXPORT_SYMBOL(csum_and_copy_from_iter);
726 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
729 const char *from = addr;
732 if (unlikely(bytes > i->count))
735 if (unlikely(!bytes))
739 iterate_and_advance(i, bytes, v, ({
741 next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
745 sum = csum_block_add(sum, next, off);
750 char *p = kmap_atomic(v.bv_page);
751 next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len,
755 sum = csum_block_add(sum, next, off);
758 next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len,
761 sum = csum_block_add(sum, next, off);
768 EXPORT_SYMBOL(csum_and_copy_to_iter);
770 int iov_iter_npages(const struct iov_iter *i, int maxpages)
772 size_t size = i->count;
778 iterate_all_kinds(i, size, v, ({
779 unsigned long p = (unsigned long)v.iov_base;
780 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
782 if (npages >= maxpages)
786 if (npages >= maxpages)
789 unsigned long p = (unsigned long)v.iov_base;
790 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
792 if (npages >= maxpages)
798 EXPORT_SYMBOL(iov_iter_npages);
800 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
803 if (new->type & ITER_BVEC)
804 return new->bvec = kmemdup(new->bvec,
805 new->nr_segs * sizeof(struct bio_vec),
808 /* iovec and kvec have identical layout */
809 return new->iov = kmemdup(new->iov,
810 new->nr_segs * sizeof(struct iovec),
813 EXPORT_SYMBOL(dup_iter);
815 int import_iovec(int type, const struct iovec __user * uvector,
816 unsigned nr_segs, unsigned fast_segs,
817 struct iovec **iov, struct iov_iter *i)
821 n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
829 iov_iter_init(i, type, p, nr_segs, n);
830 *iov = p == *iov ? NULL : p;
833 EXPORT_SYMBOL(import_iovec);
836 #include <linux/compat.h>
838 int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
839 unsigned nr_segs, unsigned fast_segs,
840 struct iovec **iov, struct iov_iter *i)
844 n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
852 iov_iter_init(i, type, p, nr_segs, n);
853 *iov = p == *iov ? NULL : p;
858 int import_single_range(int rw, void __user *buf, size_t len,
859 struct iovec *iov, struct iov_iter *i)
861 if (len > MAX_RW_COUNT)
863 if (unlikely(!access_ok(!rw, buf, len)))
868 iov_iter_init(i, rw, iov, 1, len);
871 EXPORT_SYMBOL(import_single_range);