Merge tag 'mm-stable-2025-12-11-11-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull more MM updates from Andrew Morton:

 - "powerpc/pseries/cmm: two smaller fixes" (David Hildenbrand)
   fixes a couple of minor things in ppc land

 - "Improve folio split related functions" (Zi Yan)
   some cleanups and minorish fixes in the folio splitting code

* tag 'mm-stable-2025-12-11-11-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/damon/tests/core-kunit: avoid damos_test_commit stack warning
  mm: vmscan: correct nr_requested tracing in scan_folios
  MAINTAINERS: add idr core-api doc file to XARRAY
  mm/hugetlb: fix incorrect error return from hugetlb_reserve_pages()
  mm: fix CONFIG_STACK_GROWSUP typo in mm.h
  mm/huge_memory: fix folio split stats counting
  mm/huge_memory: make min_order_for_split() always return an order
  mm/huge_memory: replace can_split_folio() with direct refcount calculation
  mm/huge_memory: change folio_split_supported() to folio_check_splittable()
  mm/sparse: fix sparse_vmemmap_init_nid_early definition without CONFIG_SPARSEMEM
  powerpc/pseries/cmm: adjust BALLOON_MIGRATE when migrating pages
  powerpc/pseries/cmm: call balloon_devinfo_init() also without CONFIG_BALLOON_COMPACTION

1 files changed, 18 insertions, 7 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9e7815b4f058..51273baec9e5 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6579,6 +6579,7 @@ long hugetlb_reserve_pages(struct inode *inode,
 	struct resv_map *resv_map;
 	struct hugetlb_cgroup *h_cg = NULL;
 	long gbl_reserve, regions_needed = 0;
+	int err;
 
 	/* This should never happen */
 	if (from > to) {
@@ -6612,8 +6613,10 @@ long hugetlb_reserve_pages(struct inode *inode,
 	} else {
 		/* Private mapping. */
 		resv_map = resv_map_alloc();
-		if (!resv_map)
+		if (!resv_map) {
+			err = -ENOMEM;
 			goto out_err;
+		}
 
 		chg = to - from;
 
@@ -6621,11 +6624,15 @@ long hugetlb_reserve_pages(struct inode *inode,
 		set_vma_desc_resv_flags(desc, HPAGE_RESV_OWNER);
 	}
 
-	if (chg < 0)
+	if (chg < 0) {
+		/* region_chg() above can return -ENOMEM */
+		err = (chg == -ENOMEM) ? -ENOMEM : -EINVAL;
 		goto out_err;
+	}
 
-	if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
-				chg * pages_per_huge_page(h), &h_cg) < 0)
+	err = hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
+				chg * pages_per_huge_page(h), &h_cg);
+	if (err < 0)
 		goto out_err;
 
 	if (desc && !(desc->vm_flags & VM_MAYSHARE) && h_cg) {
@@ -6641,14 +6648,17 @@ long hugetlb_reserve_pages(struct inode *inode,
 	 * reservations already in place (gbl_reserve).
 	 */
 	gbl_reserve = hugepage_subpool_get_pages(spool, chg);
-	if (gbl_reserve < 0)
+	if (gbl_reserve < 0) {
+		err = gbl_reserve;
 		goto out_uncharge_cgroup;
+	}
 
 	/*
 	 * Check enough hugepages are available for the reservation.
 	 * Hand the pages back to the subpool if there are not
 	 */
-	if (hugetlb_acct_memory(h, gbl_reserve) < 0)
+	err = hugetlb_acct_memory(h, gbl_reserve);
+	if (err < 0)
 		goto out_put_pages;
 
 	/*
@@ -6667,6 +6677,7 @@ long hugetlb_reserve_pages(struct inode *inode,
 
 		if (unlikely(add < 0)) {
 			hugetlb_acct_memory(h, -gbl_reserve);
+			err = add;
 			goto out_put_pages;
 		} else if (unlikely(chg > add)) {
 			/*
@@ -6726,7 +6737,7 @@ out_err:
 		kref_put(&resv_map->refs, resv_map_release);
 		set_vma_desc_resv_map(desc, NULL);
 	}
-	return chg < 0 ? chg : add < 0 ? add : -EINVAL;
+	return err;
 }
 
 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,