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 @@ -922,9 +922,12 @@ 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);