commit 11d49e9d089ccec81be87c2386dfdd010d7f7f6e upstream.
we are advancing sg as we go, so the pages we need to drop in
case of error are *before* the current sg.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>