+ mm-hugetlb-use-direct-assignment-instead-of-folio_change_private.patch added to mm-unstable branch

+ mm-hugetlb-use-direct-assignment-instead-of-folio_change_private.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/hugetlb: use direct assignment instead of folio_change_private()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-hugetlb-use-direct-assignment-instead-of-folio_change_private.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb-use-direct-assignment-instead-of-folio_change_private.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Zi Yan <ziy@nvidia.com>
Subject: mm/hugetlb: use direct assignment instead of folio_change_private()
Date: Sun, 20 Sep 2026 22:28:01 -0400

folio_change_private() should be used along with folio_attach_private() and
folio_detach_private(), where adding and remove ->private content requires
folio refcount change. add_hugetlb_folio() simply sets folio->private to
NULL without refcount manipulation. Change it to direct assignment to avoid
semantic confusion.

It prepares for a future commit that remove PG_private.

No functional change intended.

Assisted-by: LLM
Link: https://lore.kernel.org/20260920-remove-pg_private-v5-5-bb68b6a21869@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Usama Arif <usama.arif@linux.dev>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
---

 mm/hugetlb.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

--- a/mm/hugetlb.c~mm-hugetlb-use-direct-assignment-instead-of-folio_change_private
+++ a/mm/hugetlb.c
@@ -1446,11 +1446,8 @@ void add_hugetlb_folio(struct hstate *h,
 	}
 
 	__folio_set_hugetlb(folio);
-	folio_change_private(folio, NULL);
-	/*
-	 * We have to set hugetlb_vmemmap_optimized again as above
-	 * folio_change_private(folio, NULL) cleared it.
-	 */
+	/* Clear all folio->private flags except hugetlb_vmemmap_optimized. */
+	folio->private = NULL;
 	folio_set_hugetlb_vmemmap_optimized(folio);
 
 	arch_clear_hugetlb_flags(folio);
_

Patches currently in -mm which might be from ziy@nvidia.com are

mm-zsmalloc-replace-pg_private-with-pointer-comparison.patch
perf-ring_buffer-stop-using-pg_private-as-aux-page-high-order-marker.patch
xen-grant-table-stop-setting-pg_private-on-pages-for-grant-mapping.patch
fscrypt-stop-setting-pg_private-on-bounce-page.patch
mm-hugetlb-use-direct-assignment-instead-of-folio_change_private.patch
f2fs-stop-using-pg_private.patch
f2fs-convert-the-private-flag-helpers-to-folio-only.patch
erofs-mm-pagemap-add-readahead_folio_last-to-avoid-folio-private.patch
erofs-use-folio_attach-detach_private-instead-of-direct-assignment.patch
mm-page-flags-check-page-folio-private-instead-of-pg_private.patch
treewide-remove-folio_set-clear_private-usage.patch
ceph-replace-pageprivate-with-page_private.patch
treewide-remove-pageprivate-and-pg_private-from-comments-and-docs.patch
mm-page-flags-remove-pg_private.patch
usb-gadgetfs-do-not-warn-about-excessively-large-memory-allocations.patch