ascend inclusion
category: Feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4NDAW
CVE: NA

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

This is a simple wrap of walk_page_range() to get all the pages of a
spa. It doesn't support holes.
Signed-off-by: NWang Wensheng <wangwensheng4@huawei.com>
Signed-off-by: NTang Yizhou <tangyizhou@huawei.com>
Reviewed-by: Kefeng Wang<wangkefeng.wang@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>