Commit c03f05f1 authored by Al Viro's avatar Al Viro
Browse files

fix copy_page_from_iter() for compound destinations 



had been broken for ITER_BVEC et.al. since ever (OK, v3.17 when
ITER_BVEC had first appeared)...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c7d57ab1

lib/iov_iter.c

+18 −4
Original line number Original line Diff line number Diff line
@@ -738,13 +738,27 @@ EXPORT_SYMBOL(copy_page_to_iter); 
size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,

size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,

			 struct iov_iter *i)

			 struct iov_iter *i)

{

{

	if (page_copy_sane(page, offset, bytes)) {

	size_t res = 0;

	if (!page_copy_sane(page, offset, bytes))

		return 0;

	page += offset / PAGE_SIZE; // first subpage

	offset %= PAGE_SIZE;

	while (1) {

		void *kaddr = kmap_local_page(page);

		void *kaddr = kmap_local_page(page);

		size_t wanted = _copy_from_iter(kaddr + offset, bytes, i);

		size_t n = min(bytes, (size_t)PAGE_SIZE - offset);

		n = _copy_from_iter(kaddr + offset, n, i);

		kunmap_local(kaddr);

		kunmap_local(kaddr);

		return wanted;

		res += n;

		bytes -= n;

		if (!bytes || !n)

			break;

		offset += n;

		if (offset == PAGE_SIZE) {

			page++;

			offset = 0;

		}

		}

	return 0;

	}

	return res;

}

}

EXPORT_SYMBOL(copy_page_from_iter);

EXPORT_SYMBOL(copy_page_from_iter);