| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.13 036/800] copy_page_to_iter(): fix ITER_DISCARD case | Date | Mon, 12 Jul 2021 08:00:59 +0200 |
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From: Al Viro <viro@zeniv.linux.org.uk>
commit a506abc7b644d71966a75337d5a534f531b3cdc4 upstream.
we need to advance the iterator...
Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- lib/iov_iter.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -967,9 +967,12 @@ size_t copy_page_to_iter(struct page *pa size_t wanted = copy_to_iter(kaddr + offset, bytes, i); kunmap_atomic(kaddr); return wanted; - } else if (unlikely(iov_iter_is_discard(i))) + } else if (unlikely(iov_iter_is_discard(i))) { + if (unlikely(i->count < bytes)) + bytes = i->count; + i->count -= bytes; return bytes; - else if (likely(!iov_iter_is_pipe(i))) + } else if (likely(!iov_iter_is_pipe(i))) return copy_page_to_iter_iovec(page, offset, bytes, i); else return copy_page_to_iter_pipe(page, offset, bytes, i);
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