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| author |   Al Viro <viro@zeniv.linux.org.uk> | 2022-07-29 12:54:53 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2022-08-08 22:37:26 -0400 |
| commit | c03f05f183cd15f4259684ab658fbc3d23797d99 (patch) | |
| tree | 0913d63d42f83b6fc80113446df4b3891acbcdae /lib/iov_iter.c | |
| parent | hugetlbfs: copy_page_to_iter() can deal with compound pages (diff) | |
| download | linux-dev-c03f05f183cd15f4259684ab658fbc3d23797d99.tar.xz linux-dev-c03f05f183cd15f4259684ab658fbc3d23797d99.zip | |
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: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'lib/iov_iter.c')
| -rw-r--r-- | lib/iov_iter.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 4e3696d349a4..4b7fce72e3e5 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -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, 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); - 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); - 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); |