mm/mempolicy: use policy_node helper with MPOL_PREFERRED_MANY

mainline inclusion
from mainline-v5.17-rc1
commit c0455116
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6I1Z2
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c04551162167368022a61899843821bbf015b473

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

Patch series "mm: add new syscall set_mempolicy_home_node", v6.

This patch (of 3):

A followup patch will enable setting a home node with
MPOL_PREFERRED_MANY memory policy.  To facilitate that switch to using
policy_node helper.  There is no functional change in this patch.

Link: https://lkml.kernel.org/r/20211202123810.267175-1-aneesh.kumar@linux.ibm.com
Link: https://lkml.kernel.org/r/20211202123810.267175-2-aneesh.kumar@linux.ibm.com


Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Ben Widawsky <ben.widawsky@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>