1 #include <linux/export.h>
3 #include <linux/pagemap.h>
4 #include <linux/slab.h>
5 #include <linux/vmalloc.h>
6 #include <linux/splice.h>
7 #include <net/checksum.h>
9 #define PIPE_PARANOIA /* for now */
11 #define iterate_iovec(i, n, __v, __p, skip, STEP) { \
15 __v.iov_len = min(n, __p->iov_len - skip); \
16 if (likely(__v.iov_len)) { \
17 __v.iov_base = __p->iov_base + skip; \
19 __v.iov_len -= left; \
20 skip += __v.iov_len; \
25 while (unlikely(!left && n)) { \
27 __v.iov_len = min(n, __p->iov_len); \
28 if (unlikely(!__v.iov_len)) \
30 __v.iov_base = __p->iov_base; \
32 __v.iov_len -= left; \
39 #define iterate_kvec(i, n, __v, __p, skip, STEP) { \
42 __v.iov_len = min(n, __p->iov_len - skip); \
43 if (likely(__v.iov_len)) { \
44 __v.iov_base = __p->iov_base + skip; \
46 skip += __v.iov_len; \
49 while (unlikely(n)) { \
51 __v.iov_len = min(n, __p->iov_len); \
52 if (unlikely(!__v.iov_len)) \
54 __v.iov_base = __p->iov_base; \
62 #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \
63 struct bvec_iter __start; \
64 __start.bi_size = n; \
65 __start.bi_bvec_done = skip; \
67 for_each_bvec(__v, i->bvec, __bi, __start) { \
74 #define iterate_all_kinds(i, n, v, I, B, K) { \
75 size_t skip = i->iov_offset; \
76 if (unlikely(i->type & ITER_BVEC)) { \
78 struct bvec_iter __bi; \
79 iterate_bvec(i, n, v, __bi, skip, (B)) \
80 } else if (unlikely(i->type & ITER_KVEC)) { \
81 const struct kvec *kvec; \
83 iterate_kvec(i, n, v, kvec, skip, (K)) \
85 const struct iovec *iov; \
87 iterate_iovec(i, n, v, iov, skip, (I)) \
91 #define iterate_and_advance(i, n, v, I, B, K) { \
92 if (unlikely(i->count < n)) \
95 size_t skip = i->iov_offset; \
96 if (unlikely(i->type & ITER_BVEC)) { \
97 const struct bio_vec *bvec = i->bvec; \
99 struct bvec_iter __bi; \
100 iterate_bvec(i, n, v, __bi, skip, (B)) \
101 i->bvec = __bvec_iter_bvec(i->bvec, __bi); \
102 i->nr_segs -= i->bvec - bvec; \
103 skip = __bi.bi_bvec_done; \
104 } else if (unlikely(i->type & ITER_KVEC)) { \
105 const struct kvec *kvec; \
107 iterate_kvec(i, n, v, kvec, skip, (K)) \
108 if (skip == kvec->iov_len) { \
112 i->nr_segs -= kvec - i->kvec; \
115 const struct iovec *iov; \
117 iterate_iovec(i, n, v, iov, skip, (I)) \
118 if (skip == iov->iov_len) { \
122 i->nr_segs -= iov - i->iov; \
126 i->iov_offset = skip; \
130 static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
133 size_t skip, copy, left, wanted;
134 const struct iovec *iov;
138 if (unlikely(bytes > i->count))
141 if (unlikely(!bytes))
146 skip = i->iov_offset;
147 buf = iov->iov_base + skip;
148 copy = min(bytes, iov->iov_len - skip);
150 if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) {
151 kaddr = kmap_atomic(page);
152 from = kaddr + offset;
154 /* first chunk, usually the only one */
155 left = __copy_to_user_inatomic(buf, from, copy);
161 while (unlikely(!left && bytes)) {
164 copy = min(bytes, iov->iov_len);
165 left = __copy_to_user_inatomic(buf, from, copy);
171 if (likely(!bytes)) {
172 kunmap_atomic(kaddr);
175 offset = from - kaddr;
177 kunmap_atomic(kaddr);
178 copy = min(bytes, iov->iov_len - skip);
180 /* Too bad - revert to non-atomic kmap */
183 from = kaddr + offset;
184 left = __copy_to_user(buf, from, copy);
189 while (unlikely(!left && bytes)) {
192 copy = min(bytes, iov->iov_len);
193 left = __copy_to_user(buf, from, copy);
202 if (skip == iov->iov_len) {
206 i->count -= wanted - bytes;
207 i->nr_segs -= iov - i->iov;
209 i->iov_offset = skip;
210 return wanted - bytes;
213 static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
216 size_t skip, copy, left, wanted;
217 const struct iovec *iov;
221 if (unlikely(bytes > i->count))
224 if (unlikely(!bytes))
229 skip = i->iov_offset;
230 buf = iov->iov_base + skip;
231 copy = min(bytes, iov->iov_len - skip);
233 if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) {
234 kaddr = kmap_atomic(page);
237 /* first chunk, usually the only one */
238 left = __copy_from_user_inatomic(to, buf, copy);
244 while (unlikely(!left && bytes)) {
247 copy = min(bytes, iov->iov_len);
248 left = __copy_from_user_inatomic(to, buf, copy);
254 if (likely(!bytes)) {
255 kunmap_atomic(kaddr);
260 kunmap_atomic(kaddr);
261 copy = min(bytes, iov->iov_len - skip);
263 /* Too bad - revert to non-atomic kmap */
267 left = __copy_from_user(to, buf, copy);
272 while (unlikely(!left && bytes)) {
275 copy = min(bytes, iov->iov_len);
276 left = __copy_from_user(to, buf, copy);
285 if (skip == iov->iov_len) {
289 i->count -= wanted - bytes;
290 i->nr_segs -= iov - i->iov;
292 i->iov_offset = skip;
293 return wanted - bytes;
297 static bool sanity(const struct iov_iter *i)
299 struct pipe_inode_info *pipe = i->pipe;
301 int next = pipe->curbuf + pipe->nrbufs;
303 struct pipe_buffer *p;
304 if (unlikely(!pipe->nrbufs))
305 goto Bad; // pipe must be non-empty
306 if (unlikely(idx != ((next - 1) & (pipe->buffers - 1))))
307 goto Bad; // must be at the last buffer...
309 p = &pipe->bufs[idx];
310 if (unlikely(p->offset + p->len != i->iov_offset))
311 goto Bad; // ... at the end of segment
313 if (idx != (next & (pipe->buffers - 1)))
314 goto Bad; // must be right after the last buffer
318 printk(KERN_ERR "idx = %d, offset = %zd\n", i->idx, i->iov_offset);
319 printk(KERN_ERR "curbuf = %d, nrbufs = %d, buffers = %d\n",
320 pipe->curbuf, pipe->nrbufs, pipe->buffers);
321 for (idx = 0; idx < pipe->buffers; idx++)
322 printk(KERN_ERR "[%p %p %d %d]\n",
324 pipe->bufs[idx].page,
325 pipe->bufs[idx].offset,
326 pipe->bufs[idx].len);
331 #define sanity(i) true
334 static inline int next_idx(int idx, struct pipe_inode_info *pipe)
336 return (idx + 1) & (pipe->buffers - 1);
339 static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes,
342 struct pipe_inode_info *pipe = i->pipe;
343 struct pipe_buffer *buf;
347 if (unlikely(bytes > i->count))
350 if (unlikely(!bytes))
358 buf = &pipe->bufs[idx];
360 if (offset == off && buf->page == page) {
361 /* merge with the last one */
363 i->iov_offset += bytes;
366 idx = next_idx(idx, pipe);
367 buf = &pipe->bufs[idx];
369 if (idx == pipe->curbuf && pipe->nrbufs)
372 buf->ops = &page_cache_pipe_buf_ops;
373 get_page(buf->page = page);
374 buf->offset = offset;
376 i->iov_offset = offset + bytes;
384 * Fault in one or more iovecs of the given iov_iter, to a maximum length of
385 * bytes. For each iovec, fault in each page that constitutes the iovec.
387 * Return 0 on success, or non-zero if the memory could not be accessed (i.e.
388 * because it is an invalid address).
390 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
392 size_t skip = i->iov_offset;
393 const struct iovec *iov;
397 if (iter_is_iovec(i)) {
398 iterate_iovec(i, bytes, v, iov, skip, ({
399 err = fault_in_pages_readable(v.iov_base, v.iov_len);
406 EXPORT_SYMBOL(iov_iter_fault_in_readable);
408 void iov_iter_init(struct iov_iter *i, int direction,
409 const struct iovec *iov, unsigned long nr_segs,
412 /* It will get better. Eventually... */
413 if (segment_eq(get_fs(), KERNEL_DS)) {
414 direction |= ITER_KVEC;
416 i->kvec = (struct kvec *)iov;
421 i->nr_segs = nr_segs;
425 EXPORT_SYMBOL(iov_iter_init);
427 static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
429 char *from = kmap_atomic(page);
430 memcpy(to, from + offset, len);
434 static void memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len)
436 char *to = kmap_atomic(page);
437 memcpy(to + offset, from, len);
441 static void memzero_page(struct page *page, size_t offset, size_t len)
443 char *addr = kmap_atomic(page);
444 memset(addr + offset, 0, len);
448 static inline bool allocated(struct pipe_buffer *buf)
450 return buf->ops == &default_pipe_buf_ops;
453 static inline void data_start(const struct iov_iter *i, int *idxp, size_t *offp)
455 size_t off = i->iov_offset;
457 if (off && (!allocated(&i->pipe->bufs[idx]) || off == PAGE_SIZE)) {
458 idx = next_idx(idx, i->pipe);
465 static size_t push_pipe(struct iov_iter *i, size_t size,
466 int *idxp, size_t *offp)
468 struct pipe_inode_info *pipe = i->pipe;
473 if (unlikely(size > i->count))
479 data_start(i, &idx, &off);
483 left -= PAGE_SIZE - off;
485 pipe->bufs[idx].len += size;
488 pipe->bufs[idx].len = PAGE_SIZE;
489 idx = next_idx(idx, pipe);
491 while (idx != pipe->curbuf || !pipe->nrbufs) {
492 struct page *page = alloc_page(GFP_USER);
496 pipe->bufs[idx].ops = &default_pipe_buf_ops;
497 pipe->bufs[idx].page = page;
498 pipe->bufs[idx].offset = 0;
499 if (left <= PAGE_SIZE) {
500 pipe->bufs[idx].len = left;
503 pipe->bufs[idx].len = PAGE_SIZE;
505 idx = next_idx(idx, pipe);
510 static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
513 struct pipe_inode_info *pipe = i->pipe;
520 bytes = n = push_pipe(i, bytes, &idx, &off);
523 for ( ; n; idx = next_idx(idx, pipe), off = 0) {
524 size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
525 memcpy_to_page(pipe->bufs[idx].page, off, addr, chunk);
527 i->iov_offset = off + chunk;
535 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
537 const char *from = addr;
538 if (unlikely(i->type & ITER_PIPE))
539 return copy_pipe_to_iter(addr, bytes, i);
540 iterate_and_advance(i, bytes, v,
541 __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
543 memcpy_to_page(v.bv_page, v.bv_offset,
544 (from += v.bv_len) - v.bv_len, v.bv_len),
545 memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)
550 EXPORT_SYMBOL(copy_to_iter);
552 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
555 if (unlikely(i->type & ITER_PIPE)) {
559 iterate_and_advance(i, bytes, v,
560 __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
562 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
563 v.bv_offset, v.bv_len),
564 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
569 EXPORT_SYMBOL(copy_from_iter);
571 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
574 if (unlikely(i->type & ITER_PIPE)) {
578 iterate_and_advance(i, bytes, v,
579 __copy_from_user_nocache((to += v.iov_len) - v.iov_len,
580 v.iov_base, v.iov_len),
581 memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
582 v.bv_offset, v.bv_len),
583 memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
588 EXPORT_SYMBOL(copy_from_iter_nocache);
590 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
593 if (i->type & (ITER_BVEC|ITER_KVEC)) {
594 void *kaddr = kmap_atomic(page);
595 size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
596 kunmap_atomic(kaddr);
598 } else if (likely(!(i->type & ITER_PIPE)))
599 return copy_page_to_iter_iovec(page, offset, bytes, i);
601 return copy_page_to_iter_pipe(page, offset, bytes, i);
603 EXPORT_SYMBOL(copy_page_to_iter);
605 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
608 if (unlikely(i->type & ITER_PIPE)) {
612 if (i->type & (ITER_BVEC|ITER_KVEC)) {
613 void *kaddr = kmap_atomic(page);
614 size_t wanted = copy_from_iter(kaddr + offset, bytes, i);
615 kunmap_atomic(kaddr);
618 return copy_page_from_iter_iovec(page, offset, bytes, i);
620 EXPORT_SYMBOL(copy_page_from_iter);
622 static size_t pipe_zero(size_t bytes, struct iov_iter *i)
624 struct pipe_inode_info *pipe = i->pipe;
631 bytes = n = push_pipe(i, bytes, &idx, &off);
635 for ( ; n; idx = next_idx(idx, pipe), off = 0) {
636 size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
637 memzero_page(pipe->bufs[idx].page, off, chunk);
639 i->iov_offset = off + chunk;
646 size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
648 if (unlikely(i->type & ITER_PIPE))
649 return pipe_zero(bytes, i);
650 iterate_and_advance(i, bytes, v,
651 __clear_user(v.iov_base, v.iov_len),
652 memzero_page(v.bv_page, v.bv_offset, v.bv_len),
653 memset(v.iov_base, 0, v.iov_len)
658 EXPORT_SYMBOL(iov_iter_zero);
660 size_t iov_iter_copy_from_user_atomic(struct page *page,
661 struct iov_iter *i, unsigned long offset, size_t bytes)
663 char *kaddr = kmap_atomic(page), *p = kaddr + offset;
664 if (unlikely(i->type & ITER_PIPE)) {
665 kunmap_atomic(kaddr);
669 iterate_all_kinds(i, bytes, v,
670 __copy_from_user_inatomic((p += v.iov_len) - v.iov_len,
671 v.iov_base, v.iov_len),
672 memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
673 v.bv_offset, v.bv_len),
674 memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
676 kunmap_atomic(kaddr);
679 EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
681 static inline void pipe_truncate(struct iov_iter *i)
683 struct pipe_inode_info *pipe = i->pipe;
685 size_t off = i->iov_offset;
687 int nrbufs = (idx - pipe->curbuf) & (pipe->buffers - 1);
689 pipe->bufs[idx].len = off - pipe->bufs[idx].offset;
690 idx = next_idx(idx, pipe);
693 while (pipe->nrbufs > nrbufs) {
694 pipe_buf_release(pipe, &pipe->bufs[idx]);
695 idx = next_idx(idx, pipe);
701 static void pipe_advance(struct iov_iter *i, size_t size)
703 struct pipe_inode_info *pipe = i->pipe;
704 if (unlikely(i->count < size))
707 struct pipe_buffer *buf;
708 size_t off = i->iov_offset, left = size;
710 if (off) /* make it relative to the beginning of buffer */
711 left += off - pipe->bufs[idx].offset;
713 buf = &pipe->bufs[idx];
714 if (left <= buf->len)
717 idx = next_idx(idx, pipe);
720 i->iov_offset = buf->offset + left;
723 /* ... and discard everything past that point */
727 void iov_iter_advance(struct iov_iter *i, size_t size)
729 if (unlikely(i->type & ITER_PIPE)) {
730 pipe_advance(i, size);
733 iterate_and_advance(i, size, v, 0, 0, 0)
735 EXPORT_SYMBOL(iov_iter_advance);
737 void iov_iter_revert(struct iov_iter *i, size_t unroll)
742 if (unlikely(i->type & ITER_PIPE)) {
743 struct pipe_inode_info *pipe = i->pipe;
745 size_t off = i->iov_offset;
747 size_t n = off - pipe->bufs[idx].offset;
753 if (!unroll && idx == i->start_idx) {
758 idx = pipe->buffers - 1;
759 off = pipe->bufs[idx].offset + pipe->bufs[idx].len;
766 if (unroll <= i->iov_offset) {
767 i->iov_offset -= unroll;
770 unroll -= i->iov_offset;
771 if (i->type & ITER_BVEC) {
772 const struct bio_vec *bvec = i->bvec;
774 size_t n = (--bvec)->bv_len;
778 i->iov_offset = n - unroll;
783 } else { /* same logics for iovec and kvec */
784 const struct iovec *iov = i->iov;
786 size_t n = (--iov)->iov_len;
790 i->iov_offset = n - unroll;
797 EXPORT_SYMBOL(iov_iter_revert);
800 * Return the count of just the current iov_iter segment.
802 size_t iov_iter_single_seg_count(const struct iov_iter *i)
804 if (unlikely(i->type & ITER_PIPE))
805 return i->count; // it is a silly place, anyway
808 else if (i->type & ITER_BVEC)
809 return min(i->count, i->bvec->bv_len - i->iov_offset);
811 return min(i->count, i->iov->iov_len - i->iov_offset);
813 EXPORT_SYMBOL(iov_iter_single_seg_count);
815 void iov_iter_kvec(struct iov_iter *i, int direction,
816 const struct kvec *kvec, unsigned long nr_segs,
819 BUG_ON(!(direction & ITER_KVEC));
822 i->nr_segs = nr_segs;
826 EXPORT_SYMBOL(iov_iter_kvec);
828 void iov_iter_bvec(struct iov_iter *i, int direction,
829 const struct bio_vec *bvec, unsigned long nr_segs,
832 BUG_ON(!(direction & ITER_BVEC));
835 i->nr_segs = nr_segs;
839 EXPORT_SYMBOL(iov_iter_bvec);
841 void iov_iter_pipe(struct iov_iter *i, int direction,
842 struct pipe_inode_info *pipe,
845 BUG_ON(direction != ITER_PIPE);
846 WARN_ON(pipe->nrbufs == pipe->buffers);
849 i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
852 i->start_idx = i->idx;
854 EXPORT_SYMBOL(iov_iter_pipe);
856 unsigned long iov_iter_alignment(const struct iov_iter *i)
858 unsigned long res = 0;
859 size_t size = i->count;
864 if (unlikely(i->type & ITER_PIPE)) {
865 if (i->iov_offset && allocated(&i->pipe->bufs[i->idx]))
866 return size | i->iov_offset;
869 iterate_all_kinds(i, size, v,
870 (res |= (unsigned long)v.iov_base | v.iov_len, 0),
871 res |= v.bv_offset | v.bv_len,
872 res |= (unsigned long)v.iov_base | v.iov_len
876 EXPORT_SYMBOL(iov_iter_alignment);
878 unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
880 unsigned long res = 0;
881 size_t size = i->count;
885 if (unlikely(i->type & ITER_PIPE)) {
890 iterate_all_kinds(i, size, v,
891 (res |= (!res ? 0 : (unsigned long)v.iov_base) |
892 (size != v.iov_len ? size : 0), 0),
893 (res |= (!res ? 0 : (unsigned long)v.bv_offset) |
894 (size != v.bv_len ? size : 0)),
895 (res |= (!res ? 0 : (unsigned long)v.iov_base) |
896 (size != v.iov_len ? size : 0))
900 EXPORT_SYMBOL(iov_iter_gap_alignment);
902 static inline size_t __pipe_get_pages(struct iov_iter *i,
908 struct pipe_inode_info *pipe = i->pipe;
909 ssize_t n = push_pipe(i, maxsize, &idx, start);
916 get_page(*pages++ = pipe->bufs[idx].page);
917 idx = next_idx(idx, pipe);
924 static ssize_t pipe_get_pages(struct iov_iter *i,
925 struct page **pages, size_t maxsize, unsigned maxpages,
935 data_start(i, &idx, start);
936 /* some of this one + all after this one */
937 npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1;
938 capacity = min(npages,maxpages) * PAGE_SIZE - *start;
940 return __pipe_get_pages(i, min(maxsize, capacity), pages, idx, start);
943 ssize_t iov_iter_get_pages(struct iov_iter *i,
944 struct page **pages, size_t maxsize, unsigned maxpages,
947 if (maxsize > i->count)
953 if (unlikely(i->type & ITER_PIPE))
954 return pipe_get_pages(i, pages, maxsize, maxpages, start);
955 iterate_all_kinds(i, maxsize, v, ({
956 unsigned long addr = (unsigned long)v.iov_base;
957 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
961 if (len > maxpages * PAGE_SIZE)
962 len = maxpages * PAGE_SIZE;
963 addr &= ~(PAGE_SIZE - 1);
964 n = DIV_ROUND_UP(len, PAGE_SIZE);
965 res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
966 if (unlikely(res < 0))
968 return (res == n ? len : res * PAGE_SIZE) - *start;
970 /* can't be more than PAGE_SIZE */
971 *start = v.bv_offset;
972 get_page(*pages = v.bv_page);
980 EXPORT_SYMBOL(iov_iter_get_pages);
982 static struct page **get_pages_array(size_t n)
984 struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
986 p = vmalloc(n * sizeof(struct page *));
990 static ssize_t pipe_get_pages_alloc(struct iov_iter *i,
991 struct page ***pages, size_t maxsize,
1002 data_start(i, &idx, start);
1003 /* some of this one + all after this one */
1004 npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1;
1005 n = npages * PAGE_SIZE - *start;
1009 npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
1010 p = get_pages_array(npages);
1013 n = __pipe_get_pages(i, maxsize, p, idx, start);
1021 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
1022 struct page ***pages, size_t maxsize,
1027 if (maxsize > i->count)
1033 if (unlikely(i->type & ITER_PIPE))
1034 return pipe_get_pages_alloc(i, pages, maxsize, start);
1035 iterate_all_kinds(i, maxsize, v, ({
1036 unsigned long addr = (unsigned long)v.iov_base;
1037 size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
1041 addr &= ~(PAGE_SIZE - 1);
1042 n = DIV_ROUND_UP(len, PAGE_SIZE);
1043 p = get_pages_array(n);
1046 res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
1047 if (unlikely(res < 0)) {
1052 return (res == n ? len : res * PAGE_SIZE) - *start;
1054 /* can't be more than PAGE_SIZE */
1055 *start = v.bv_offset;
1056 *pages = p = get_pages_array(1);
1059 get_page(*p = v.bv_page);
1067 EXPORT_SYMBOL(iov_iter_get_pages_alloc);
1069 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
1076 if (unlikely(i->type & ITER_PIPE)) {
1080 iterate_and_advance(i, bytes, v, ({
1082 next = csum_and_copy_from_user(v.iov_base,
1083 (to += v.iov_len) - v.iov_len,
1084 v.iov_len, 0, &err);
1086 sum = csum_block_add(sum, next, off);
1089 err ? v.iov_len : 0;
1091 char *p = kmap_atomic(v.bv_page);
1092 next = csum_partial_copy_nocheck(p + v.bv_offset,
1093 (to += v.bv_len) - v.bv_len,
1096 sum = csum_block_add(sum, next, off);
1099 next = csum_partial_copy_nocheck(v.iov_base,
1100 (to += v.iov_len) - v.iov_len,
1102 sum = csum_block_add(sum, next, off);
1109 EXPORT_SYMBOL(csum_and_copy_from_iter);
1111 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
1114 const char *from = addr;
1118 if (unlikely(i->type & ITER_PIPE)) {
1119 WARN_ON(1); /* for now */
1122 iterate_and_advance(i, bytes, v, ({
1124 next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
1126 v.iov_len, 0, &err);
1128 sum = csum_block_add(sum, next, off);
1131 err ? v.iov_len : 0;
1133 char *p = kmap_atomic(v.bv_page);
1134 next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len,
1138 sum = csum_block_add(sum, next, off);
1141 next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len,
1144 sum = csum_block_add(sum, next, off);
1151 EXPORT_SYMBOL(csum_and_copy_to_iter);
1153 int iov_iter_npages(const struct iov_iter *i, int maxpages)
1155 size_t size = i->count;
1161 if (unlikely(i->type & ITER_PIPE)) {
1162 struct pipe_inode_info *pipe = i->pipe;
1169 data_start(i, &idx, &off);
1170 /* some of this one + all after this one */
1171 npages = ((pipe->curbuf - idx - 1) & (pipe->buffers - 1)) + 1;
1172 if (npages >= maxpages)
1174 } else iterate_all_kinds(i, size, v, ({
1175 unsigned long p = (unsigned long)v.iov_base;
1176 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
1178 if (npages >= maxpages)
1182 if (npages >= maxpages)
1185 unsigned long p = (unsigned long)v.iov_base;
1186 npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
1188 if (npages >= maxpages)
1194 EXPORT_SYMBOL(iov_iter_npages);
1196 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
1199 if (unlikely(new->type & ITER_PIPE)) {
1203 if (new->type & ITER_BVEC)
1204 return new->bvec = kmemdup(new->bvec,
1205 new->nr_segs * sizeof(struct bio_vec),
1208 /* iovec and kvec have identical layout */
1209 return new->iov = kmemdup(new->iov,
1210 new->nr_segs * sizeof(struct iovec),
1213 EXPORT_SYMBOL(dup_iter);
1216 * import_iovec() - Copy an array of &struct iovec from userspace
1217 * into the kernel, check that it is valid, and initialize a new
1218 * &struct iov_iter iterator to access it.
1220 * @type: One of %READ or %WRITE.
1221 * @uvector: Pointer to the userspace array.
1222 * @nr_segs: Number of elements in userspace array.
1223 * @fast_segs: Number of elements in @iov.
1224 * @iov: (input and output parameter) Pointer to pointer to (usually small
1225 * on-stack) kernel array.
1226 * @i: Pointer to iterator that will be initialized on success.
1228 * If the array pointed to by *@iov is large enough to hold all @nr_segs,
1229 * then this function places %NULL in *@iov on return. Otherwise, a new
1230 * array will be allocated and the result placed in *@iov. This means that
1231 * the caller may call kfree() on *@iov regardless of whether the small
1232 * on-stack array was used or not (and regardless of whether this function
1233 * returns an error or not).
1235 * Return: 0 on success or negative error code on error.
1237 int import_iovec(int type, const struct iovec __user * uvector,
1238 unsigned nr_segs, unsigned fast_segs,
1239 struct iovec **iov, struct iov_iter *i)
1243 n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
1251 iov_iter_init(i, type, p, nr_segs, n);
1252 *iov = p == *iov ? NULL : p;
1255 EXPORT_SYMBOL(import_iovec);
1257 #ifdef CONFIG_COMPAT
1258 #include <linux/compat.h>
1260 int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
1261 unsigned nr_segs, unsigned fast_segs,
1262 struct iovec **iov, struct iov_iter *i)
1266 n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
1274 iov_iter_init(i, type, p, nr_segs, n);
1275 *iov = p == *iov ? NULL : p;
1280 int import_single_range(int rw, void __user *buf, size_t len,
1281 struct iovec *iov, struct iov_iter *i)
1283 if (len > MAX_RW_COUNT)
1285 if (unlikely(!access_ok(!rw, buf, len)))
1288 iov->iov_base = buf;
1290 iov_iter_init(i, rw, iov, 1, len);
1293 EXPORT_SYMBOL(import_single_range);