ascend inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4M23J
CVE: NA

-------------------------------------------------

Don't use the spa's va_start if the spa is not valid.
Signed-off-by: NDing Tianhong <dingtianhong@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>