Buggy client might pass zero nlimbs which is meaningless.
Added check for zero length.
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Reviewed-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NJames Morris <jmorris@namei.org>