Use IS_ERR() and PTR_ERR() instead of PTR_ZRR_OR_ZERO()
to simplify code, avoid redundant paramenter definitions
and judgements.
Signed-off-by: NZhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: NTang Bin <tangbin@cmss.chinamobile.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>