From 51216825099e36bf9d39de375749d8365556c5fc Mon Sep 17 00:00:00 2001 From: Hongfu Li Date: Wed, 19 Aug 2026 17:51:43 +0800 Subject: [PATCH] mm: use a folio in the softleaf_is_device_private path Use the folio APIs in the device_private migration path of do_swap_page(), replacing four calls to compound_head() with two page_folio() calls. The second one re-fetches the folio from vmf->page after migrate_to_ram(), which might have split the folio. Link: https://lore.kernel.org/20260819095144.45660-1-hongfu.li@linux.dev Signed-off-by: Hongfu Li Signed-off-by: Andrew Morton Suggested-by: David Hildenbrand (Arm) Link: https://lore.kernel.org/all/e20678ed-3fa1-4677-a1d7-e2af481e8302@kernel.org/ Acked-by: David Hildenbrand (Arm) Reviewed-by: Lorenzo Stoakes (ARM) Reviewed-by: Anshuman Khandual Cc: Liam R. Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka --- mm/memory.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 8b0c2c735d3d..9cbce5c90bff 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4926,18 +4926,21 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) goto unlock; /* - * Get a page reference while we know the page can't be - * freed. + * Get a folio reference while we know the folio can't + * be freed. */ - if (trylock_page(vmf->page)) { + folio = page_folio(vmf->page); + if (folio_trylock(folio)) { struct dev_pagemap *pgmap; - get_page(vmf->page); + folio_get(folio); pte_unmap_unlock(vmf->pte, vmf->ptl); pgmap = page_pgmap(vmf->page); ret = pgmap->ops->migrate_to_ram(vmf); - unlock_page(vmf->page); - put_page(vmf->page); + /* migrate_to_ram() might have split the folio. */ + folio = page_folio(vmf->page); + folio_unlock(folio); + folio_put(folio); } else { pte_unmap(vmf->pte); softleaf_entry_wait_on_locked(entry, vmf->ptl);