[PATCH v5 05/17] mm/hugetlb: use direct assignment instead of folio_change_private()

[Zi Yan <ziy@nvidia.com>]

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
To: Muchun Song <muchun.song@linux.dev>
To: Oscar Salvador <osalvador@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.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>
Signed-off-by: Zi Yan <ziy@nvidia.com>
---
 mm/hugetlb.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 2003439ea13c6..7b27c3c5c3e58 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1446,11 +1446,8 @@ void add_hugetlb_folio(struct hstate *h, struct folio *folio,
 	}
 
 	__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);

-- 
2.53.0