1 #include <linux/export.h>
2 #include <linux/bvec.h>
4 #include <linux/pagemap.h>
5 #include <linux/slab.h>
6 #include <linux/vmalloc.h>
7 #include <linux/splice.h>
8 #include <net/checksum.h>
10 #define PIPE_PARANOIA /* for now */
12 #define iterate_iovec(i, n, __v, __p, skip, STEP) { \
16 __v.iov_len = min(n, __p->iov_len - skip); \
17 if (likely(__v.iov_len)) { \
18 __v.iov_base = __p->iov_base + skip; \
20 __v.iov_len -= left; \
21 skip += __v.iov_len; \
26 while (unlikely(!left && n)) { \
28 __v.iov_len = min(n, __p->iov_len); \
29 if (unlikely(!__v.iov_len)) \
31 __v.iov_base = __p->iov_base; \
33 __v.iov_len -= left; \
40 #define iterate_kvec(i, n, __v, __p, skip, STEP) { \
43 __v.iov_len = min(n, __p->iov_len - skip); \
44 if (likely(__v.iov_len)) { \
45 __v.iov_base = __p->iov_base + skip; \
47 skip += __v.iov_len; \
50 while (unlikely(n)) { \
52 __v.iov_len = min(n, __p->iov_len); \
53 if (unlikely(!__v.iov_len)) \
55 __v.iov_base = __p->iov_base; \
63 #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \
64 struct bvec_iter __start; \
65 __start.bi_size = n; \
66 __start.bi_bvec_done = skip; \
68 for_each_bvec(__v, i->bvec, __bi, __start) { \
75 #define iterate_all_kinds(i, n, v, I, B, K) { \
77 size_t skip = i->iov_offset; \
78 if (unlikely(i->type & ITER_BVEC)) { \
80 struct bvec_iter __bi; \
81 iterate_bvec(i, n, v, __bi, skip, (B)) \
82 } else if (unlikely(i->type & ITER_KVEC)) { \
83 const struct kvec *kvec; \
85 iterate_kvec(i, n, v, kvec, skip, (K)) \
87 const struct iovec *iov; \
89 iterate_iovec(i, n, v, iov, skip, (I)) \
94 #define iterate_and_advance(i, n, v, I, B, K) { \
95 if (unlikely(i->count < n)) \
98 size_t skip = i->iov_offset; \
99 if (unlikely(i->type & ITER_BVEC)) { \
100 const struct bio_vec *bvec = i->bvec; \
102 struct bvec_iter __bi; \
103 iterate_bvec(i, n, v, __bi, skip, (B)) \
104 i->bvec = __bvec_iter_bvec(i->bvec, __bi); \
105 i->nr_segs -= i->bvec - bvec; \
106 skip = __bi.bi_bvec_done; \
107 } else if (unlikely(i->type & ITER_KVEC)) { \
108 const struct kvec *kvec; \
110 iterate_kvec(i, n, v, kvec, skip, (K)) \
111 if (skip == kvec->iov_len) { \
115 i->nr_segs -= kvec - i->kvec; \
118 const struct iovec *iov; \
120 iterate_iovec(i, n, v, iov, skip, (I)) \
121 if (skip == iov->iov_len) { \
125 i->nr_segs -= iov - i->iov; \
129 i->iov_offset = skip; \
133 static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
136 size_t skip, copy, left, wanted;
137 const struct iovec *iov;
141 if (unlikely(bytes > i->count))
144 if (unlikely(!bytes))
149 skip = i->iov_offset;
150 buf = iov->iov_base + skip;
151 copy = min(bytes, iov->iov_len - skip);
153 if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) {
154 kaddr = kmap_atomic(page);
155 from = kaddr + offset;
157 /* first chunk, usually the only one */
158 left = __copy_to_user_inatomic(buf, from, copy);
164 while (unlikely(!left && bytes)) {
167 copy = min(bytes, iov->iov_len);
168 left = __copy_to_user_inatomic(buf, from, copy);
174 if (likely(!bytes)) {
175 kunmap_atomic(kaddr);
178 offset = from - kaddr;
180 kunmap_atomic(kaddr);
181 copy = min(bytes, iov->iov_len - skip);
183 /* Too bad - revert to non-atomic kmap */
186 from = kaddr + offset;
187 left = __copy_to_user(buf, from, copy);
192 while (unlikely(!left && bytes)) {
195 copy = min(bytes, iov->iov_len);
196 left = __copy_to_user(buf, from, copy);
205 if (skip == iov->iov_len) {
209 i->count -= wanted - bytes;
210 i->nr_segs -= iov - i->iov;
212 i->iov_offset = skip;
213 return wanted - bytes;
216 static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
219 size_t skip, copy, left, wanted;
220 const struct iovec *iov;
224 if (unlikely(bytes > i->count))
227 if (unlikely(!bytes))
232 skip = i->iov_offset;
233 buf = iov->iov_base + skip;
234 copy = min(bytes, iov->iov_len - skip);
236 if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) {
237 kaddr = kmap_atomic(page);
240 /* first chunk, usually the only one */
241 left = __copy_from_user_inatomic(to, buf, copy);
247 while (unlikely(!left && bytes)) {
250 copy = min(bytes, iov->iov_len);
251 left = __copy_from_user_inatomic(to, buf, copy);
257 if (likely(!bytes)) {
258 kunmap_atomic(kaddr);
263 kunmap_atomic(kaddr);
264 copy = min(bytes, iov->iov_len - skip);
266 /* Too bad - revert to non-atomic kmap */
270 left = __copy_from_user(to, buf, copy);
275 while (unlikely(!left && bytes)) {
278 copy = min(bytes, iov->iov_len);
279 left = __copy_from_user(to, buf, copy);
288 if (skip == iov->iov_len) {
292 i->count -= wanted - bytes;
293 i->nr_segs -= iov - i->iov;
295 i->iov_offset = skip;
296 return wanted - bytes;
300 static bool sanity(const struct iov_iter *i)
302 struct pipe_inode_info *pipe = i->pipe;
304 int next = pipe->curbuf + pipe->nrbufs;
306 struct pipe_buffer *p;
307 if (unlikely(!pipe->nrbufs))
308 goto Bad; // pipe must be non-empty
309 if (unlikely(idx != ((next - 1) & (pipe->buffers - 1))))
310 goto Bad; // must be at the last buffer...
312 p = &pipe->bufs[idx];
313 if (unlikely(p->offset + p->len != i->iov_offset))
314 goto Bad; // ... at the end of segment
316 if (idx != (next & (pipe->buffers - 1)))
317 goto Bad; // must be right after the last buffer
321 printk(KERN_ERR "idx = %d, offset = %zd\n", i->idx, i->iov_offset);
322 printk(KERN_ERR "curbuf = %d, nrbufs = %d, buffers = %d\n",
323 pipe->curbuf, pipe->nrbufs, pipe->buffers);
324 for (idx = 0; idx < pipe->buffers; idx++)
325 printk(KERN_ERR "[%p %p %d %d]\n",
327 pipe->bufs[idx].page,
328 pipe->bufs[idx].offset,
329 pipe->bufs[idx].len);
334 #define sanity(i) true
337 static inline int next_idx(int idx, struct pipe_inode_info *pipe)
339 return (idx + 1) & (pipe->buffers - 1);
342 static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes,
345 struct pipe_inode_info *pipe = i->pipe;
346 struct pipe_buffer *buf;
350 if (unlikely(bytes > i->count))
353 if (unlikely(!bytes))
361 buf = &pipe->bufs[idx];
363 if (offset == off && buf->page == page) {
364 /* merge with the last one */
366 i->iov_offset += bytes;
369 idx = next_idx(idx, pipe);
370 buf = &pipe->bufs[idx];
372 if (idx == pipe->curbuf && pipe->nrbufs)
375 buf->ops = &page_cache_pipe_buf_ops;
376 get_page(buf->page = page);
377 buf->offset = offset;
379 i->iov_offset = offset + bytes;
387 * Fault in one or more iovecs of the given iov_iter, to a maximum length of
388 * bytes. For each iovec, fault in each page that constitutes the iovec.
390 * Return 0 on success, or non-zero if the memory could not be accessed (i.e.
391 * because it is an invalid address).
393 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
395 size_t skip = i->iov_offset;
396 const struct iovec *iov;
400 if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
401 iterate_iovec(i, bytes, v, iov, skip, ({
402 err = fault_in_pages_readable(v.iov_base, v.iov_len);
409 EXPORT_SYMBOL(iov_iter_fault_in_readable);
411 void iov_iter_init(struct iov_iter *i, int direction,
412 const struct iovec *iov, unsigned long nr_segs,
415 /* It will get better. Eventually... */
416 if (segment_eq(get_fs(), KERNEL_DS)) {
417 direction |= ITER_KVEC;
419 i->kvec = (struct kvec *)iov;
424 i->nr_segs = nr_segs;
428 EXPORT_SYMBOL(iov_iter_init);
430 static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
432 char *from = kmap_atomic(page);
433 memcpy(to, from + offset, len);
437 static void memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len)
439 char *to = kmap_atomic(page);
440 memcpy(to + offset, from, len);
444 static void memzero_page(struct page *page, size_t offset, size_t len)
446 char *addr = kmap_atomic(page);
447 memset(addr + offset, 0, len);
451 static inline bool allocated(struct pipe_buffer *buf)
453 return buf->ops == &default_pipe_buf_ops;
456 static inline void data_start(const struct iov_iter *i, int *idxp, size_t *offp)
458 size_t off = i->iov_offset;
460 if (off && (!allocated(&i->pipe->bufs[idx]) || off == PAGE_SIZE)) {
461 idx = next_idx(idx, i->pipe);
468 static size_t push_pipe(struct iov_iter *i, size_t size,
469 int *idxp, size_t *offp)
471 struct pipe_inode_info *pipe = i->pipe;
476 if (unlikely(size > i->count))
482 data_start(i, &idx, &off);
486 left -= PAGE_SIZE - off;
488 pipe->bufs[idx].len += size;
491 pipe->bufs[idx].len = PAGE_SIZE;
492 idx = next_idx(idx, pipe);
494 while (idx != pipe->curbuf || !pipe->nrbufs) {
495 struct page *page = alloc_page(GFP_USER);
499 pipe->bufs[idx].ops = &default_pipe_buf_ops;
500 pipe->bufs[idx].page = page;
501 pipe->bufs[idx].offset = 0;
502 if (left <= PAGE_SIZE) {
503 pipe->bufs[idx].len = left;
506 pipe->bufs[idx].len = PAGE_SIZE;
508 idx = next_idx(idx, pipe);
513 static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
516 struct pipe_inode_info *pipe = i->pipe;
523 bytes = n = push_pipe(i, bytes, &idx, &off);
526 for ( ; n; idx = next_idx(idx, pipe), off = 0) {
527 size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
528 memcpy_to_page(pipe->bufs[idx].page, off, addr, chunk);
530 i->iov_offset = off + chunk;
538 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
540 const char *from = addr;
541 if (unlikely(i->type & ITER_PIPE))
542 return copy_pipe_to_iter(addr, bytes, i);
543 iterate_and_advance(i, bytes, v,
544 __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
546 memcpy_to_page(v.bv_page, v.bv_offset,
547 (from += v.bv_len) - v.bv_len, v.bv_len),
548 memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)
553 EXPORT_SYMBOL(copy_to_iter);
555 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
558 if (unlikely(i->type & ITER_PIPE)) {
562 iterate_and_advance(i, bytes, v,
563 __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
565 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
566 v.bv_offset, v.bv_len),
567 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
572 EXPORT_SYMBOL(copy_from_iter);
574 bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
577 if (unlikely(i->type & ITER_PIPE)) {
581 if (unlikely(i->count < bytes))
584 iterate_all_kinds(i, bytes, v, ({
585 if (__copy_from_user((to += v.iov_len) - v.iov_len,
586 v.iov_base, v.iov_len))
589 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
590 v.bv_offset, v.bv_len),
591 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
594 iov_iter_advance(i, bytes);
597 EXPORT_SYMBOL(copy_from_iter_full);
599 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
602 if (unlikely(i->type & ITER_PIPE)) {
606 iterate_and_advance(i, bytes, v,
607 __copy_from_user_nocache((to += v.iov_len) - v.iov_len,
608 v.iov_base, v.iov_len),
609 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
610 v.bv_offset, v.bv_len),
611 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
616 EXPORT_SYMBOL(copy_from_iter_nocache);
618 bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
621 if (unlikely(i->type & ITER_PIPE)) {
625 if (unlikely(i->count < bytes))
627 iterate_all_kinds(i, bytes, v, ({
628 if (__copy_from_user_nocache((to += v.iov_len) - v.iov_len,
629 v.iov_base, v.iov_len))
632 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
633 v.bv_offset, v.bv_len),
634 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
637 iov_iter_advance(i, bytes);
640 EXPORT_SYMBOL(copy_from_iter_full_nocache);
642 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
645 if (i->type & (ITER_BVEC|ITER_KVEC)) {
646 void *kaddr = kmap_atomic(page);
647 size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
648 kunmap_atomic(kaddr);
650 } else if (likely(!(i->type & ITER_PIPE)))
651 return copy_page_to_iter_iovec(page, offset, bytes, i);
653 return copy_page_to_iter_pipe(page, offset, bytes, i);
655 EXPORT_SYMBOL(copy_page_to_iter);
657 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
660 if (unlikely(i->type & ITER_PIPE)) {
664 if (i->type & (ITER_BVEC|ITER_KVEC)) {
665 void *kaddr = kmap_atomic(page);
666 size_t wanted = copy_from_iter(kaddr + offset, bytes, i);
667 kunmap_atomic(kaddr);
670 return copy_page_from_iter_iovec(page, offset, bytes, i);
672 EXPORT_SYMBOL(copy_page_from_iter);
674 static size_t pipe_zero(size_t bytes, struct iov_iter *i)
676 struct pipe_inode_info *pipe = i->pipe;
683 bytes = n = push_pipe(i, bytes, &idx, &off);
687 for ( ; n; idx = next_idx(idx, pipe), off = 0) {
688 size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
689 memzero_page(pipe->bufs[idx].page, off, chunk);
691 i->iov_offset = off + chunk;
698 size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
700 if (unlikely(i->type & ITER_PIPE))
701 return pipe_zero(bytes, i);
702 iterate_and_advance(i, bytes, v,
703 __clear_user(v.iov_base, v.iov_len),
704 memzero_page(v.bv_page, v.bv_offset, v.bv_len),
705 memset(v.iov_base, 0, v.iov_len)
710 EXPORT_SYMBOL(iov_iter_zero);
712 size_t iov_iter_copy_from_user_atomic(struct page *page,
713 struct iov_iter *i, unsigned long offset, size_t bytes)
715 char *kaddr = kmap_atomic(page), *p = kaddr + offset;
716 if (unlikely(i->type & ITER_PIPE)) {
717 kunmap_atomic(kaddr);
721 iterate_all_kinds(i, bytes, v,
722 __copy_from_user_inatomic((p += v.iov_len) - v.iov_len,
723 v.iov_base, v.iov_len),
724 memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
725 v.bv_offset, v.bv_len),
726 memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
728 kunmap_atomic(kaddr);
731 EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
733 static void pipe_advance(struct iov_iter *i, size_t size)
735 struct pipe_inode_info *pipe = i->pipe;
736 struct pipe_buffer *buf;
738 size_t off = i->iov_offset, orig_sz;
740 if (unlikely(i->count < size))
745 if (off) /* make it relative to the beginning of buffer */
746 size += off - pipe->bufs[idx].offset;
748 buf = &pipe->bufs[idx];
749 if (size <= buf->len)
752 idx = next_idx(idx, pipe);
756 off = i->iov_offset = buf->offset + size;
759 idx = next_idx(idx, pipe);
761 int unused = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
762 /* [curbuf,unused) is in use. Free [idx,unused) */
763 while (idx != unused) {
764 pipe_buf_release(pipe, &pipe->bufs[idx]);
765 idx = next_idx(idx, pipe);
772 void iov_iter_advance(struct iov_iter *i, size_t size)
774 if (unlikely(i->type & ITER_PIPE)) {
775 pipe_advance(i, size);
778 iterate_and_advance(i, size, v, 0, 0, 0)
780 EXPORT_SYMBOL(iov_iter_advance);
783 * Return the count of just the current iov_iter segment.
785 size_t iov_iter_single_seg_count(const struct iov_iter *i)
787 if (unlikely(i->type & ITER_PIPE))
788 return i->count; // it is a silly place, anyway
791 else if (i->type & ITER_BVEC)
792 return min(i->count, i->bvec->bv_len - i->iov_offset);
794 return min(i->count, i->iov->iov_len - i->iov_offset);
796 EXPORT_SYMBOL(iov_iter_single_seg_count);
798 void iov_iter_kvec(struct iov_iter *i, int direction,
799 const struct kvec *kvec, unsigned long nr_segs,
802 BUG_ON(!(direction & ITER_KVEC));
805 i->nr_segs = nr_segs;
809 EXPORT_SYMBOL(iov_iter_kvec);
811 void iov_iter_bvec(struct iov_iter *i, int direction,
812 const struct bio_vec *bvec, unsigned long nr_segs,
815 BUG_ON(!(direction & ITER_BVEC));
818 i->nr_segs = nr_segs;
822 EXPORT_SYMBOL(iov_iter_bvec);
824 void iov_iter_pipe(struct iov_iter *i, int direction,
825 struct pipe_inode_info *pipe,
828 BUG_ON(direction != ITER_PIPE);
831 i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
835 EXPORT_SYMBOL(iov_iter_pipe);
837 unsigned long iov_iter_alignment(const struct iov_iter *i)
839 unsigned long res = 0;
840 size_t size = i->count;
842 if (unlikely(i->type & ITER_PIPE)) {
843 if (size && i->iov_offset && allocated(&i->pipe->bufs[i->idx]))
844 return size | i->iov_offset;
847 iterate_all_kinds(i, size, v,
848 (res |= (unsigned long)v.iov_base | v.iov_len, 0),
849 res |= v.bv_offset | v.bv_len,
850 res |= (unsigned long)v.iov_base | v.iov_len
854 EXPORT_SYMBOL(iov_iter_alignment);
856 unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
858 unsigned long res = 0;
859 size_t size = i->count;
861 if (unlikely(i->type & ITER_PIPE)) {
866 iterate_all_kinds(i, size, v,
867 (res |= (!res ? 0 : (unsigned long)v.iov_base) |
868 (size != v.iov_len ? size : 0), 0),
869 (res |= (!res ? 0 : (unsigned long)v.bv_offset) |
870 (size != v.bv_len ? size : 0)),
871 (res |= (!res ? 0 : (unsigned long)v.iov_base) |
872 (size != v.iov_len ? size : 0))
876 EXPORT_SYMBOL(iov_iter_gap_alignment);
878 static inline size_t __pipe_get_pages(struct iov_iter *i,
884 struct pipe_inode_info *pipe = i->pipe;
885 ssize_t n = push_pipe(i, maxsize, &idx, start);
892 get_page(*pages++ = pipe->bufs[idx].page);
893 idx = next_idx(idx, pipe);
900 static ssize_t pipe_get_pages(struct iov_iter *i,
901 struct page **pages, size_t maxsize, unsigned maxpages,
914 data_start(i, &idx, start);
915 /* some of this one + all after this one */
916 npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1;
917 capacity = min(npages,maxpages) * PAGE_SIZE - *start;
919 return __pipe_get_pages(i, min(maxsize, capacity), pages, idx, start);
922 ssize_t iov_iter_get_pages(struct iov_iter *i,
923 struct page **pages, size_t maxsize, unsigned maxpages,
926 if (maxsize > i->count)
929 if (unlikely(i->type & ITER_PIPE))
930 return pipe_get_pages(i, pages, maxsize, maxpages, start);
931 iterate_all_kinds(i, maxsize, v, ({
932 unsigned long addr = (unsigned long)v.iov_base;
933 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
937 if (len > maxpages * PAGE_SIZE)
938 len = maxpages * PAGE_SIZE;
939 addr &= ~(PAGE_SIZE - 1);
940 n = DIV_ROUND_UP(len, PAGE_SIZE);
941 res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
942 if (unlikely(res < 0))
944 return (res == n ? len : res * PAGE_SIZE) - *start;
946 /* can't be more than PAGE_SIZE */
947 *start = v.bv_offset;
948 get_page(*pages = v.bv_page);
956 EXPORT_SYMBOL(iov_iter_get_pages);
958 static struct page **get_pages_array(size_t n)
960 struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
962 p = vmalloc(n * sizeof(struct page *));
966 static ssize_t pipe_get_pages_alloc(struct iov_iter *i,
967 struct page ***pages, size_t maxsize,
981 data_start(i, &idx, start);
982 /* some of this one + all after this one */
983 npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1;
984 n = npages * PAGE_SIZE - *start;
988 npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
989 p = get_pages_array(npages);
992 n = __pipe_get_pages(i, maxsize, p, idx, start);
1000 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
1001 struct page ***pages, size_t maxsize,
1006 if (maxsize > i->count)
1009 if (unlikely(i->type & ITER_PIPE))
1010 return pipe_get_pages_alloc(i, pages, maxsize, start);
1011 iterate_all_kinds(i, maxsize, v, ({
1012 unsigned long addr = (unsigned long)v.iov_base;
1013 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
1017 addr &= ~(PAGE_SIZE - 1);
1018 n = DIV_ROUND_UP(len, PAGE_SIZE);
1019 p = get_pages_array(n);
1022 res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
1023 if (unlikely(res < 0)) {
1028 return (res == n ? len : res * PAGE_SIZE) - *start;
1030 /* can't be more than PAGE_SIZE */
1031 *start = v.bv_offset;
1032 *pages = p = get_pages_array(1);
1035 get_page(*p = v.bv_page);
1043 EXPORT_SYMBOL(iov_iter_get_pages_alloc);
1045 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
1052 if (unlikely(i->type & ITER_PIPE)) {
1056 iterate_and_advance(i, bytes, v, ({
1058 next = csum_and_copy_from_user(v.iov_base,
1059 (to += v.iov_len) - v.iov_len,
1060 v.iov_len, 0, &err);
1062 sum = csum_block_add(sum, next, off);
1065 err ? v.iov_len : 0;
1067 char *p = kmap_atomic(v.bv_page);
1068 next = csum_partial_copy_nocheck(p + v.bv_offset,
1069 (to += v.bv_len) - v.bv_len,
1072 sum = csum_block_add(sum, next, off);
1075 next = csum_partial_copy_nocheck(v.iov_base,
1076 (to += v.iov_len) - v.iov_len,
1078 sum = csum_block_add(sum, next, off);
1085 EXPORT_SYMBOL(csum_and_copy_from_iter);
1087 bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
1094 if (unlikely(i->type & ITER_PIPE)) {
1098 if (unlikely(i->count < bytes))
1100 iterate_all_kinds(i, bytes, v, ({
1102 next = csum_and_copy_from_user(v.iov_base,
1103 (to += v.iov_len) - v.iov_len,
1104 v.iov_len, 0, &err);
1107 sum = csum_block_add(sum, next, off);
1111 char *p = kmap_atomic(v.bv_page);
1112 next = csum_partial_copy_nocheck(p + v.bv_offset,
1113 (to += v.bv_len) - v.bv_len,
1116 sum = csum_block_add(sum, next, off);
1119 next = csum_partial_copy_nocheck(v.iov_base,
1120 (to += v.iov_len) - v.iov_len,
1122 sum = csum_block_add(sum, next, off);
1127 iov_iter_advance(i, bytes);
1130 EXPORT_SYMBOL(csum_and_copy_from_iter_full);
1132 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
1135 const char *from = addr;
1139 if (unlikely(i->type & ITER_PIPE)) {
1140 WARN_ON(1); /* for now */
1143 iterate_and_advance(i, bytes, v, ({
1145 next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
1147 v.iov_len, 0, &err);
1149 sum = csum_block_add(sum, next, off);
1152 err ? v.iov_len : 0;
1154 char *p = kmap_atomic(v.bv_page);
1155 next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len,
1159 sum = csum_block_add(sum, next, off);
1162 next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len,
1165 sum = csum_block_add(sum, next, off);
1172 EXPORT_SYMBOL(csum_and_copy_to_iter);
1174 int iov_iter_npages(const struct iov_iter *i, int maxpages)
1176 size_t size = i->count;
1182 if (unlikely(i->type & ITER_PIPE)) {
1183 struct pipe_inode_info *pipe = i->pipe;
1190 data_start(i, &idx, &off);
1191 /* some of this one + all after this one */
1192 npages = ((pipe->curbuf - idx - 1) & (pipe->buffers - 1)) + 1;
1193 if (npages >= maxpages)
1195 } else iterate_all_kinds(i, size, v, ({
1196 unsigned long p = (unsigned long)v.iov_base;
1197 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
1199 if (npages >= maxpages)
1203 if (npages >= maxpages)
1206 unsigned long p = (unsigned long)v.iov_base;
1207 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
1209 if (npages >= maxpages)
1215 EXPORT_SYMBOL(iov_iter_npages);
1217 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
1220 if (unlikely(new->type & ITER_PIPE)) {
1224 if (new->type & ITER_BVEC)
1225 return new->bvec = kmemdup(new->bvec,
1226 new->nr_segs * sizeof(struct bio_vec),
1229 /* iovec and kvec have identical layout */
1230 return new->iov = kmemdup(new->iov,
1231 new->nr_segs * sizeof(struct iovec),
1234 EXPORT_SYMBOL(dup_iter);
1237 * import_iovec() - Copy an array of &struct iovec from userspace
1238 * into the kernel, check that it is valid, and initialize a new
1239 * &struct iov_iter iterator to access it.
1241 * @type: One of %READ or %WRITE.
1242 * @uvector: Pointer to the userspace array.
1243 * @nr_segs: Number of elements in userspace array.
1244 * @fast_segs: Number of elements in @iov.
1245 * @iov: (input and output parameter) Pointer to pointer to (usually small
1246 * on-stack) kernel array.
1247 * @i: Pointer to iterator that will be initialized on success.
1249 * If the array pointed to by *@iov is large enough to hold all @nr_segs,
1250 * then this function places %NULL in *@iov on return. Otherwise, a new
1251 * array will be allocated and the result placed in *@iov. This means that
1252 * the caller may call kfree() on *@iov regardless of whether the small
1253 * on-stack array was used or not (and regardless of whether this function
1254 * returns an error or not).
1256 * Return: 0 on success or negative error code on error.
1258 int import_iovec(int type, const struct iovec __user * uvector,
1259 unsigned nr_segs, unsigned fast_segs,
1260 struct iovec **iov, struct iov_iter *i)
1264 n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
1272 iov_iter_init(i, type, p, nr_segs, n);
1273 *iov = p == *iov ? NULL : p;
1276 EXPORT_SYMBOL(import_iovec);
1278 #ifdef CONFIG_COMPAT
1279 #include <linux/compat.h>
1281 int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
1282 unsigned nr_segs, unsigned fast_segs,
1283 struct iovec **iov, struct iov_iter *i)
1287 n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
1295 iov_iter_init(i, type, p, nr_segs, n);
1296 *iov = p == *iov ? NULL : p;
1301 int import_single_range(int rw, void __user *buf, size_t len,
1302 struct iovec *iov, struct iov_iter *i)
1304 if (len > MAX_RW_COUNT)
1306 if (unlikely(!access_ok(!rw, buf, len)))
1309 iov->iov_base = buf;
1311 iov_iter_init(i, rw, iov, 1, len);
1314 EXPORT_SYMBOL(import_single_range);