mm: hugetlb: move mpol interpretation out of alloc_buddy_hugetlb_folio_with_mpol()

Move memory policy interpretation out of
alloc_buddy_hugetlb_folio_with_mpol() and into alloc_hugetlb_folio() to
separate reading and interpretation of memory policy from actual
allocation.

This will later allow memory policy to be interpreted outside of the
process of allocating a hugetlb folio entirely.  This opens doors for
other callers of the HugeTLB folio allocation function, such as
guest_memfd, where memory may not always be mapped and hence may not have
an associated vma.

Introduce struct mempolicy_interpreted to hold all the components of an
interpreted memory policy.

Rename alloc_buddy_hugetlb_folio_with_mpol() to
alloc_buddy_hugetlb_folio() since the function no longer interprets memory
policy.

No functional change intended.

Link: https://lore.kernel.org/20260702-hugetlb-open-up-v4-2-d53cefcccf34@google.com
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: James Houghton <jthoughton@google.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Yan Zhao <yan.y.zhao@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h
index 6c962d866e86..7f6fc9599693 100644
--- a/include/uapi/linux/mempolicy.h
+++ b/include/uapi/linux/mempolicy.h
@@ -16,7 +16,7 @@
  */
 
 /* Policies */
-enum {
+enum mempolicy_mode {
 	MPOL_DEFAULT,
 	MPOL_PREFERRED,
 	MPOL_BIND,